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photo | Are there any techniques to aid/improve reverse macro photography | I recently started playing with reverse macro with my canon 50mm f1.8. A couple things I noticed immediately is:
Shallow depth of field
No control over aperture
difficult to shoot handheld
I believe these are the common problems with this type of shooting
Are there any techniques that I can use to improve/help with Reverse Macro shooting besides buying a Macro lens as they are kind of expensive.
Here is what I've tried so far
ps. I have read Are there macro focusing techniques for handheld shots? but focusing isn't really a problem.
| VQAonline_00049038.png | I've faced similar problems and also was able to overcome a few of them. A few techniques that has proved to be efficient for me are:
Focus changes even if you move a millimeter. I tried so hard to keep my body as stiff as possible but that did NOT work. So, I just let it go. I start by looking at the blur image through the viewfinder, slowly move forward and start shooting as soon as the image looks clearer, keep shooting and moving all the way upto the point the image becomes blurry again. Do NOT move using your whole body/waist, instead try inhaling and exhaling slowly.
I always shoot in continuous mode which enables me to increase the chance of getting a better focused shot.
IS wont work, nor will aperture control. So, you'll need to set the aperture before detaching the lens. I usually use higher than normal ISO to be able to use a higher shutter speed, thus remove any chance of shake blur.
Not sure if you're using a reverse mount ring, if not, get one asap. It helps a lot and you can concentrate on things other than keeping your lens safe from falling.
DOF stacking is another technique you can apply. Its true I wasn't able to plan and execute DOF stacking yet, but if you take a lot of pictures of the same subject, chances are you'll find a couple or two which you can use to stack and gain greater DOF.
Use of external flash is also very helpful and let you use smaller aperture as well as higher shutter speed while keeping the ISO low. Generally you'd like to use a diffuser along with it. Use this link to get an idea about how to make your own DIY lighting setup for better macro shooting.
| https://photo.stackexchange.com/questions/20937 |
photo | Dust-like speck visible every few pictures — is it dust, or worse? | I seem to have to dust-like speck on my Sony Cybershot S950's lens, but it appears randomly every few pictures. Could something be going bad internally?
| VQAonline_00048955.png | That sure looks like sensor dust, for which I'd recommend seeing the answers in the Best way to clean a DSLR sensor thread. The spot may appear "randomly" because it only appears when you're using a narrow aperture.
That said, it seems you don't have a dSLR, thus no interchangeable lenses which are what usually causes the situation where dust can get inside the camera body. I suppose it's possible that dust got inside the camera through some other way although I think that's a fairly rare occurrence.
If the camera is still under warranty, it's worth a call to the manufacturer.
| https://photo.stackexchange.com/questions/11215 |
photo | What is this red dot on the T6 camera body? | What is this red dot next to the viewfinder and live view button on the Canon EOS Rebel T6 (1300D)? I have been unable to find a reference to it online or in the basic or full instruction manuals.
| VQAonline_00049452.png |
What is this red dot next to the viewfinder and live view button on the Canon EOS Rebel T6 (1300D)?
A red dot is a common symbol for the record function, and as on other EOS bodies that button serves the dual purpose of starting Live View mode and starting and stopping movie recording. The icon on the button itself is the Live View icon, and I think the red dot next to the button just reminds you of its alternate function in movie mode.
You'll see a similar red dot on the display when the camera is recording a movie.
| https://photo.stackexchange.com/questions/77875 |
photo | What could I do to take a better picture of this outdoor fountain at night? | I was practicing with long exposure on this water fountain and here is what I got.
I would like to know what mistakes do you see I have made and how to improve such a shot? In this location if it were you what would you have done? So I can learn something new to improve.
I had a 24-70mm lens to use on a Nikon D610.
| VQAonline_00049315.png | You wanted to use the effect of long exposures.
What effects of long exposure are visible in your image?
Lights are blown out.
For the street lamp on the right, it seems to be ok.
But the neon sign is rather ugly. The name of the restaurant is hard to read.
So the long exposure doesn't work on lights close to you.
The fountain becomes a closed curtain, which is interesting.
There aren't many parts that are affected by long exposure and on some parts it even has an unpleasant effect.
What other things are in the image that could be interesting, beautiful, ...?
There's a statue on the fountain which looks good with the highlights on the dark material.
There's a symmetry to the basin of the fountain, but with the neon lights and the bright ugly building in the back, it will be hard to incorporate it into the image.
You can blur out the background, but it will still be visible.
What other image could be taken at this fountain that uses effects of long exposure?
Get closer. Most of the surroundings should not be part of the image
as they tend to look ugly under these circumstances. Getting closer to the fountain will show less of those surroundings. Place the camera on the edge of the basin. Pointing up, framing the statue and filling the bottom of the image with the curtain of water. The background should be mostly night sky, which is nice and neutral.
If the angles work out, you can try and get the street light in your shot as well, acting as a wrong sun in the background, giving the statue a nice side/back light.
Edit:
What mode&settings can be used for the fountain shot?
S is good as it let's you choose a shutter speed (a long one), right? Well, yes, it adjusts the aperture (and maybe even iso) so the exposure is "right". But the problem is that a "right" exposure for a camera means a grey one (not too dark, not too bright). Say there's a lot of black night sky in your image. The camera will try to find the average grey exposure and as a result it will probably over expose the rest of the image.
This will also brighten up the sky and it will look mushy from all the surrounding lights from the city.
In your case, a "right" exposure could be an image consisting of a lot of pure black and that's not what the camera is looking for.
In manual mode, you are in control of all the settings. This however requires a bit of knowledge about what those settings do. You say "S prevented me from picking f2.8". This implies that you want to use f2.8 on this shot. This won't work, because f2.8 means the aperture is wide open (probably as wide as your lens can go), which means a lot of light can go through the lens. With that much light, it won't take long before enough light reached the sensor for a good exposure, but you want a long one. That's why the automatic S mode picked f22, which means the aperture is closed and only a bit of light goes through the lens. So the camera takes quite a while untile enough light is captured -> this allows for a long shutter speed.
If this is new to you, it is a great opportunity to learn.
Go ahead and use Aperture priority mode and dial in the f2.8 that you apparently want to use and see what your camera picks as a shutter speed, it will not be a long exposure.
Now dial in f22 and see how much the shutter speed changes.
Both: Long shutter speeds and small f-numbers will make the image brighter, you need something to balance. that's what the S mode did by dialing in f22.
If you want to use f2.8 anyway, you have to darken the image by some other means. Often an ND filter is used to reduce the amount of light, but this is a story for another day.
This is a good stationary subject to experiment with all this. Set up the tripod. Keep two values constant (aperture and iso, for example) and play with the other one. Don't be surprised to see all white or all black images, just keep going until something shows up. You will get a feel for what these values do.
Good luck and have fun
| https://photo.stackexchange.com/questions/59364 |
physics | Why does a perpendicular force not change speed? | I have been taught that a perpendicular force acting on an object will only change the direction of its velocity, not its magnitude. The explanation that was provided to me is that because there no force in the direction of its velocity, there must be no work done and thus change in the object's kinetic energy. However, I have also studied the vectorial form of the equations of motion
$$\vec v_f = \vec v_i + \vec a\cdot t$$
So I assume that the velocity after a constant force has acted on it for a period of time is simply the vector sum of $\vec v_i $ and $\vec a \cdot t$, which I just assume is the acceleration vector (determined by the force) scaled up by a factor of the time the force acts.Diagrammatically, I took the sum as
It is obviously clear from the diagram that the new speed (which is the length of the $\vec v_f$ vector) is bigger than the previous speed.
This can be confirmed by Pythagoras's theorem, the magnitude of the $\vec v_f$ vector is
$$ |\vec v_f|=\sqrt{|\vec v_i|^2 + |\vec a|^2 \cdot t^2} $$
which is very clearly not equal to $|\vec v_i| $
So, I conclude that the speed of the object has changed even though the force acting on it was perpendicular to its velocity. So my question is, what have I missed?
Is my assumption that the final velocity is the vector sum of the initial velocity and the product of acceleration and time incorrect?
Or have I made a mistake somewhere else?
Thank you in advance for your help.
| VQAonline_00050524.png | In drawing your triangle, you assume that the object has already moved in the direction of your force (maybe just a little bit). In doing so, you forget that the force then stops being perpendicular.
What you have (re)discovered is simply that a force which is constant throughout space cannot remain perpendicular to the motion of a free particle if it lasts a finite amount of time: the particle will simply start to move in the direction of the force, picking up velocity as it starts moving in that direction.
However, if $\vec{F}$ is not of the same magnitude and direction everywhere, one can produce a force that remains perpendicular. The canonical example is that of a body exerting gravity. The direction of the force is always towards the particle (i.e. not the same everywhere). It also decreases with distance, but that's really not an essential point here. Now, if a test particle at a distance $d$ moves past the other body with the right velocity, this force will always remain perpendicular. Can you guess what kind of shape the trajectory of the test particle will trace out? Hint: think about the symmetry of the problem.
| https://physics.stackexchange.com/questions/113102 |
physics | Derivation of operator version of the classical wave equation | I have the following summarised derivation for the operator version of the classical wave equation for massless and material particle.
My question is about the statement:
However, a problem is that in the probabilistic interpretation of its solution as representing a single particle.
Difficulty comes from the two possible signs of the square root operations: $E=±\sqrt{\left(pc\right)^2+\left(mc^2\right)^2}$.
This can be shown to give rise to antiparticles which must be included for self-consistency.
Wouldn't the same problem occur for massless particles as well as it is still to the $E^2$?
| VQAonline_00053450.png | There is no unique choice of $\hat{E}$ in the first place.
You are correct in that there is a flaw in the argument from the very beginning as follows:
We know the solution for monochromatic electromagnetic plane waves as $\sim \exp(\pm i(\omega t - kx))$, not only $\sim \exp(- i(\omega t - kx))$! Furthermore, from the photoelectric effect we know that $E = \hbar \omega$. That means that we might try to define the energy operator as $\hat{E} = \pm i \hbar \partial_t$.
However, there is a problem with both of these signs from the very beginning, since we deal with real waves in electromagnetism. By choosing one fixed sign for $\hat{E}$ (and thus also $\hat{p}$), a real plane wave $\sim \exp(i(\omega t - kx)) + \exp(-i(\omega t - kx))$ would be interpreted as a superposition of particles with both positive and negative energies. Consequently, for any sign choice of $\hat{E}=\pm i \hbar \partial_t$, every real wave has zero energy!!! That is obviously unacceptable, since we derived the form of the operator from observations about real waves (the photoelectric effect).
But notice the following. If we apply $\hat{E}^2 = -\hbar^2 \partial_t^2$, it does give the right answer for a real wave. In other words, we seem to know what $\hat{E}^2$ should be, but we have no idea what $\hat{E}$ should be from the very beginning.
That is, the excerpt in the OP is misleading in omitting that the choice for the unsquared energy operator is simply unknown at the outset, be it for massive or massless particles.
Negative mass-energy currents - the historical misunderstanding
This being said, the real problem with massive particles as compared to massless ones was the following. For electromagnetism, it was kind of obvious that the $T^{00}$ component of the EM stress-energy tensor
\begin{align}
T^{00} = \frac{1}{\mu_0} \left(F^{0\kappa}F^0{}_\kappa + F^{\mu\nu}F_{\mu\nu} \right) \propto E^2 + B^2
\end{align}
is somehow proportional to the total energy density of the photons and it automatically stays positive definite. This also has a nice conservation law $T^{0\mu}{}_{,\mu} = 0$, i.e., $T^{00}$ is the zeroth component of a conserved current.
However, people were used to the complex Schrödinger equation for massive particles. In fact, they knew that the complex nature of this equation is what makes it possible to express the dynamics of, e.g., an electron in the Hydrogen atom. However, if you try to find a conserved current for the equation $(\hbar^2 \Box + m^2)\phi =0$ that reduces to the conserved matter-density current, you would only find a current that exhibited both positive and negative matter densities!
Now in retrospect we know that the conserved "matter-density current" of the Schrödinger equation is in fact the non-relativistic limit of a charge-density current. Since in the non-relativistic limit, the energies of motion are such that a single electron always stays a single electron, the charge per mass $m_e/e$ always stays the same. So we were able to multiply the charge current with $m_e/e$ and simply use it as an equivalent of a density current. However, in the relativistic case the electron can in principle be superposed with positrons, which have opposite charge $-e$. By multiplying the conserved charge current by $m_e/e$, we then got seemingly negative mass (or probability-of-occurence) densities. There is, however, a stress-energy tensor of the scalar field $T^{\mu\nu}$ which does have a (classically) positive-definite $T^{00}$ with the meaning of mass-energy density and that has been ignored because it would not correspond as easily to the Schrödinger-equation current.
So that is the whole deal with massive particles.
(P.S.: I kind of skip the part where electrons have spin and their Schrödinger equation is the non-relativistic limit of the Dirac equation. But the gist is the same.)
| https://physics.stackexchange.com/questions/607101 |
physics | Cyclist's electrical tingling under power lines | It's been happening to me for years. I finally decided to ask users who are better with "practical physics" when I was told that my experience – that I am going to describe momentarily – prove that I am a diviner, a psychic, a "sensibil" as we call it. The right explanation clearly needs some electrodynamics although it's "everyday electrodynamics" and theoretical physicists are not trained to quickly answer such questions although each of us has probably solved many exercises that depend on the same principles.
When I am biking under the power lines – which probably have a high voltage in them – I feel a clear tingling shocks near my buttocks and related parts of the body for a second or so when I am under a critical point of the power lines. It is a strong feeling, not a marginal one: it feels like a dozen of ants that are stinging me at the same moment. It seems almost clear that some currents are running through my skins at 50 Hz. I would like to know the estimate (and calculation or justification) of the voltage, currents etc. that are going through my skin and some comparison with the shock one gets when he touches the power outlet.
Now,
my bike that makes this effect particularly strong is a mountain bike, Merida;
the speed is about 20 km/h and the velocity is perpendicular to the direction of the current in the power line;
the seat has a hole in it and there is some metal – probably a conducting one – just a few centimeters away from the center of my buttocks. It's plausible that I am in touch with the metal – or near touch;
my skin is kind of sweating during these events and the liquid isn't pure water so it's probably much more conductive than pure water;
the temperature was 22 °C today, the humidity around 35%, clear skies, 10 km/h wind;
the power lines may be between 22 kV and 1 MV and at 50 Hz, the altitude is tens of meters but I don't really know exactly.
What kind of approximation for the electromagnetic waves are relevant? What is the strength? How high currents one needs?
Does one need some amplification from interference etc. (special places) to make the effect detectable? (I only remember experiencing this effect at two places around Pilsen; the most frequent place where I feel it is near Druztová, Greater Pilsen, Czechia.)
Is the motion of the wheels or even its frequency important? Is there some resonance?
Does the hole in the seat and the metal play any role? Just if you think that I am crazy, other people are experience the effect (although with different body parts), see e.g. here and here. This PDF file seems to suggest that the metals and electromagnetic induction is essential for the effect but the presentation looks neither particularly comprehensive nor impartial enough.
An extra blog discussion on this topic is here:
http://motls.blogspot.com/2012/05/electric-shocks-under-high-voltage.html
| VQAonline_00049982.png | First, Field strength.
This calculation is strictly an electric potential calculation; radiation and induction are safely ignored at 50Hz.*
For a 200kV transmission line 20m above ground, the max electric field at ground level is about 1.2 kV/m.** This number is reduced from the naive 200kV/20m=10 kV/m calculation by two effects:
1) The ~1/r variation in the electric field (reduction to 3 kV/m). I used the method of images to calculate this field, with a 10 cm conductor diameter to keep the peak field below the 1MV/m breakdown field.
2) Cancellation from the other two power lines in this 3-phase system, which are at +/-120 degree electrical phases with respect to the first, and are physically offset in a horizontal line per the photo. I estimated 7m spacings between adjacent lines. The maximum E-field actually occurs roughly twice as far out as the outermost line; the field under the center conductor is lower.
Next, Can you feel it?
1) The human body circuit model for electrostatic discharge is 100pF+1.5kohm; that's a gross simplification but better than nothing. If one imagined a 2m high network, the applied voltage results in a 50Hz current of about 70uA ($C \omega V$). Very small.
2) There will be an AC voltage difference between the (insulated) human and (insulated) bicycle. A 1m vertical separation between their centers of gravity would yield roughly 1200V. This voltage is rather small compared to some car-door-type static discharges, but it would still be sufficient to break down a short air gap (but not a couple cm), and would repeat at 100Hz. I imagine it would be noticeable in a sensitive part of the anatomy.
If the transmission voltage is actually 400 kV, all the field strengths and voltages would of course double.
(*) In response to a comment, here's an estimate of the neglected induction and radiation effects, courtesy of Maxwell 4 and 3:
Induction: Suppose a power line is carrying a healthy 1000A AC current (f=50 Hz). Then by Ampere's law, there is a circumferential AC magnetic field; at the wire-to-ground distance of 20 meters that field's amplitude is $10 \mu T$. (Compare with the earth's DC field of approximately 0.5 gauss, or $50 \mu T$.)
The flux of this magnetic field through a $1 m^2$ area loop (with normal parallel to the ground and perpendicular to the wire) is $\Phi = 10 \mu Wb$ AC. Then from Faraday's law, the voltage around the loop is $d \Phi /dt = 2 \pi f \Phi = 3 mV$ (millivolts). So much for induction.
One can also estimate the magnetic field resulting from the $1200 V/m$ ground-level AC electric field, which has an electric flux density $D =\epsilon_0 E = 10.6 nC/m^2$ and a displacement current density $\partial D / \partial t = 2 \pi f D = 3.3 \mu A/m^2$. The flux of this field through a $1 m$ square loop (parallel to the ground) is $3.3 \mu A$, so the average magnetic field around the square is $0.8 \mu A/m$, for a ridiculously small magnetic flux density of $1 pT$.
(**) 1 Sep 2014 update. Dmytry very astutely points out in a comment that there will be local electric field intensification effects from conductive irregularities in the otherwise flat ground surface, such as our cyclist (who, being somewhat sweaty, will have a conductive surface). The same principle applies to lightning rods.
For the proverbial spherical cyclist, the local field will be increased by a factor of 3, independent of the sphere's size, as long as it's much less than the distance to the power line. It turns out that it doesn't matter whether the sphere is grounded or insulated, since its total charge remains 0.
For more elongated shapes the intensification can be much higher: for a grounded prolate spheroid with 10:1 dimensions, the multiplication factor is 50. This intensification of course enhances any sensation one might feel.
| https://physics.stackexchange.com/questions/29016 |
physics | Why don't we consider both the forces while calculating the magnitude of stress in an elastic body? | Consider a wire being stretched from two ends with equal forces. We know that both of these forces collectively participate in elongating the wire; had there been one force the wire would have accelerated in the direction of force. Why can't then the stress be calculated using the two forces (knowing that the vector resultant of the two forces would come out to be zero)?
| VQAonline_00050690.png | Tricky question. Basically you would think the total force is 0 on any plane intersecting the cylinder at right angles, hence there would be no pressure, right? Well, the first point (0 net force) is correct, second is not.
Imagine being physically pulled by two equally strong friends in opposite directions. Total force is 0 so you remain standing where you are, but you will feel a stress (pressure) in your body from your pulling friends.
It helps to think of the situation from a different perspective: One force is trying to pull out (extend) the cylinder, and is therefore providing a pressure/stress on the cylinder, of magnitude P=F/A. But the cylinder is not moving, so there must be an opposite force of equal magnitude, which maintains the cohesion of the cylinder. At some level of external force this cohesion is no longer strong enough, so the external force will rip the cylinder apart.
You can think of the cohesive force as a sort of reaction (or supportive, passive) force, and the pulling as an "active" force.
| https://physics.stackexchange.com/questions/138828 |
physics | How does a canvas water bag cool water? | I was reading about this water bottle by Botl that behaves like a canvas water bags to keep water cool. I found out that this idea is an old idea and cars would drive with water bags in front as shown below.
Here is what I found out about them: it seeps water through the bag and evaporates, causing the water to cool inside. Here is where I need some help:
Why does the water seep through the bag? Is it because the water molecules have a Maxwell speed distribution and only the fastest molecules seep out?
What mechanism is occurring for heat being removed from the water to evaporate the water on the bag’s surface? Doesn't radiation also contribute here?
Why does moving increases the cooling effect faster?
| VQAonline_00050407.png | As far as I understand the idea is very simple:
as the bottle is covered in a film of water (due to a leakage of the container), this can evaporate. Due to the Boltzman distribution this will also happen well below $100°C$. The process of evaporating though takes energy from the system (called latent heat). This cools down the bottle.
If the surrounding air is "filled with water" it is harder for the liquid to evaporate and thus slowing the process, so always bringing fresh air to the system helps.
This is basically the concept of sweating as well, where you can immediately feel the effect of wind blowing on your moist skin.
Hope this helps and I didn't miss something.
| https://physics.stackexchange.com/questions/97959 |
physics | A question regarding Newton's Third Law for torques | I was trying to prove why, if two objects are rotating around some axis, and are interacting, then the sum of the torques produced on both objects via the mutual interactions will be zero. However, I am having a confusion as to how the forces are being applied. I will use a diagram to make thinks clear.
Consider the following diagram:
Here , there are two particles, $A$ and $B$, which are rotating about an axis, which is the center of this circle. Let $B$ exert a force on $A$, which I have denoted by a vector. The torque produced on $A$ is thus magnitude of the force times the perpendicular distance from the axis, which again I have shown. By Newton's third law, an equal and opposite force acts on $B$, which I have denoted by a vector, equal in magnitude but opposite in direction. Now here is my confusion: If Newton's law says that there is an equal and opposite force along the same line of action, then the torques cancel each other. But, if that is the case, then $B$ isn't lying on the line of action, so how would it experience the force? If I draw an equal and opposite vector through $B$, then the torques don't cancel each other.
Note that the force vector on $A$ is any general force, not necessarily lying on the line segment joining $A$ and $B$. What is wrong here?
| VQAonline_00051983.png | You're right; the torques only cancel out if and only if the forces are applied along the line connecting the particles. Here's the proof: Let $\vec{F}_{AB}$ be the force on $A$ due to $B$, and define $\vec{F}_{BA}$ similarly. The torque on $A$ due to $B$ is then
$$
\vec{\tau}_{AB} = \vec{r}_A \times \vec{F}_{AB}
$$
and the torque on $B$ due to $A$ is then
$$
\vec{\tau}_{BA} = \vec{r}_B \times \vec{F}_{BA}.
$$
The net torque is then
$$
\vec{\tau}_\text{net} = \vec{r}_A \times \vec{F}_{AB} + \vec{r}_B \times \vec{F}_{BA}.
$$
But by Newton's Third Law, $\vec{F}_{BA} = - \vec{F}_{AB}$, which allows us to simplify this to
$$
\vec{\tau}_\text{net} = (\vec{r}_A - \vec{r}_B) \times \vec{F}_{AB}.
$$
Note that $\vec{r}_A - \vec{r}_B$ is a vector pointing from $B$ to $A$; note also the cross product of two non-zero vectors vanishes if and only if they are parallel. We conclude that $\vec{\tau}_\text{net} = 0$ if and only if the force between the two particles acts along the line connecting them.
What this means is that in your diagram, if $A$ and $B$ are really exerting forces on each other in this way, then the net torque they exert on each other will not in fact be zero. The net torque will only be zero if the particles interact with each other via a central force, which is a fancy way of saying that the force is parallel to the line connecting the particles.
| https://physics.stackexchange.com/questions/354520 |
physics | Would like to experiment with a safe sized leyden jar | I would like to experiment with leyden jars, but do not want to mess with anything big enough to kill me should I get zapped.
What are some good guidelines as far as size when making homemade Leyden Jars?
Here is a picture of one I created, could it carry a lethal charge?
Thanks!
Ben
| VQAonline_00051812.png | The safety considerations for Leyden jars are the same as for any capacitor; these depend on how you intend to use the device and how much energy you put into it. Leyden jars have small capacitances, but they can withstand very high voltages, which means that they can store a great deal of energy, e.g. if you charge them with a Van de Graaff generator, for example.
Estimate, or better, measure the device's capacitance with an LCR meter or impedance meter.
You should measure the capacitance and check that it agrees with the estimate. A good estimate will be gotten from the formula (which you can derive from the integral form of Gauss's law):
$$C = \frac{\epsilon\,A}{d}$$
where $A$ is the surface area covered by the foil on one side of the jar, $\epsilon$ the low frequency dielectric constant of the glass (can be up to 10, considerably more than the square of the optical frequency dielectric constant) and $d$ the thickness of the glass (distance between the two foils). For 1mm thick glass, you'll get a figure of the order of $10^{-8}{\rm F}$ - about ten nanofarad.
The glass dielectric has a very high breakdown or dielectric strength; typically this is ten to thirty MV per meter, meaning that the device can withstand ten to twenty thousand volts across its electrodes. At that degree of charging, you have stored $\frac{1}{2}\,C\,V^2$ or of the order of one to ten joules. You're unlikely to get to this, but you could approach it if you charged the device with a Van de Graaff generator and this is approaching the realm of defibrillator level energies.
In short it is unlikely to be lethal, but it could be if misused. You need to plan what you want to do with it. You could try measuring the voltage across it in its charged state in a typical experiment with a high impedance voltmeter, and work out the energy stored in it with the formula $\frac{1}{2}\,C\,V^2$ with $C$ set to ten nanofarads. If you come up with a figure of more than a few millijoules, then you're in danger territory.
For example, with $A=0.05{\rm m^2}$ (wine or 1 liter softdrink bottle size), $d=1{\rm mm}$ and a relative permeability of glass, I get a capacitance of $4.4{\rm nF}$. To limit this device's energy to $0.001{\rm J}$, therefore, you need to limit the charging voltage to about $660{\rm V}$. In this state it would still deliver quite a whack to your hand. I would check these figures with a capacitance measurement for your actual device; some plastics can have rather large permeabilities.
| https://physics.stackexchange.com/questions/320472 |
pm | Can separate roles in DSDM Atern be handled by the same person? | In the DSDM Atern project delivery framework roles fit into the following three categories:
Project Level
Solution Development Team, and
Other
The diagram below shows how an Atern team is structure:
For example, in the Solution Development Team we have the roles of the Business Ambassador and the Business Analyst(s).
I appreciate that the Business Ambassador's role is more focused on the day-to-day communication between the project and the business whereas the Business Analyst role facilitates the communication between the developers (technical roles) and other business roles.
There are many organisations that insist on assigning these roles to two different people. However, in smaller organisations where the resources are limited in all categories -i.e., there is no enough people to fulfil every business role; could the same person be assigned to both roles?
What are the risks or limitations of merging these two roles?
Are there any (other) roles that lend themselves to being covered by the same people?
Are there any that definitely shouldn't be covered by the same person?
| VQAonline_00054215.png | Actually, the Business Sponsor and the Business Visionary could be the same person, in some organisations.
DSDM states that a role can be shared between more than one person, or one person may have more than one role.
Example 1- you could have several people fulflling Business Advisor role, each with their own area of specialism.
Example 2 - on a small simple project, one person could fulfil the Project Manager and Team Leader role.
We would normally only expect a single Business Visionary (rather than several Visionaries, which could add confusion) - i.e. having one Visionary is "normal", but having more than one could happen in exceptional circumstances
We expect only one Business Sponsor. (I have never ever had a project with more than one Sponsor in 18 years of doing DSDM!!)
There is no rule that says a Business Analyst and a Business Ambassador cannot be the same person. It is simply that this is an unlikely combination, since a Business Ambassador, with all their business experience, is less likely to have the analysis skills. But a good analyst / programmer might well fulfil the Business Analyst role AND the Solution Developer role (in an organisation where there are no Business Analysts)
Hope this helps
| https://pm.stackexchange.com/questions/6021 |
pm | Getting estimated working time from MS Project | Our company has just recently started using MS Project Professional 2010 and we plan to eventually have a Project Server installation. I've created a few projects so far, but still claim to be a complete novice.
A customer has just requested a quote for some work, so I've created a project plan for the proposed work, however I'd like MS Project to tell me how much working time I've allocated in the plan I've created.
The only information MS Project seems to offer is the difference between the start and end date of the project (9.38 days), but what I want is the time my staff will be working on the project, which shouldn't include lag time or times outside the calendar that I've created. I've calculated this as being 36 hours from the non-summary tasks in the example below (apologies for having to blur the task names).
Whilst this example is only tiny, I want to know how to get MS Project to calculate this for me in future on much bigger projects. Can anyone point me in the right direction or tell me what I'm doing wrong?
Update: I've found that if I allocate a new 'test' staff resource rate of £1/hour for simplicity, I can see a cost of £36, which matches the 36h I'm expecting to see.
| VQAonline_00054223.png | There are two easy ways of doing this:
Go to the "Resource Usage" view. Go you get there differs slightly depending on which version of Project you are using, but look for a Views menu or on Project 2010, look at the leftmost button on the Task tab (by default) for your Views selection. This will give you the actual time allocated for each resource in the plan broken down by task and totalled at a resource level.
Show the "Work" column in the Gantt Chart (right-click the column headings on the left side of the Gantt Chart, select "Insert Colum", add 'Work'). This will show you the actual amount of work specified for each task irrespective of the type and nature of the resources assigned to that task.
Which method you use depends on what you are comfortable with and what kind of breakdown you want to get out of it.
| https://pm.stackexchange.com/questions/10209 |
pm | How to arrange tasks around a fixed milestone? | i am tasked to take over a project that has recently taken off the ground. However, there has been no project plan and we need to create one now. Due to circumstances, I can only fix the next milestone in time and need to arrange tasks around that milestone.
This is fine for future tasks, but current tasks don't align so that they culminate into the milestone, even if they are assigned as predecessors to the milestone. If I assign the the previous tasks to the milestone as predecessors, the milestone is moved.
How can I arrange all the tasks around the milestone?
| VQAonline_00054226.png | The problem looks to be that you are scheduling the very first task from "today"... If you link them nose-to-tail the entire project will schedule from "today" and the milestone must move to accommodate that.
If you set the start date of the first task sufficiently far in the past that there is enough time to fit all the first tasks in before the milestone then all will be well. This might mean you have to set the Project Start Date in the past too.
Once you have done all that:
Fix the start of the milestone by making it a "Must start on..." or "Start no later than..."
Make the milestone a dependant of the last task in the first section (i.e. make the final previous task a predecessor of the milestone).
Make all the prior tasks "Finish as late as possible"
Hope that helps.
| https://pm.stackexchange.com/questions/14258 |
pm | Why in JIRA my field Resolution is labeled as Unresolved, when status is Resolved? | Question is pretty simple, I've a Kanban project, with a personal workflow that provides different statuses, as Resolved.
When I drag and drop to this last one through the lanes, or when I set it manually to Resolved status, the Resolution fields is still Unresolved, and one of my widget - Created VS Resolved chart - is not working properly.
Any idea?
Thanks in advance
| VQAonline_00054238.png | In JIRA, an issue is only considered resolved if it has a value in the RESOLUTION field.
The status of the issue doesn't actually matter. For example, it could have a status of RESOLVED or CLOSED but would still be considered as unresolved by JIRA if the RESOLUTION field was empty.
So, the trick to resolving issues is to ensure that you have setup your workflow correctly. Make sure that the final transition in your workflow includes the resolve issue screen.
This screen is where you set the RESOLUTION. For example, you might have a RESOLUTION of "done", "duplicate", "won't fix", etc.
| https://pm.stackexchange.com/questions/22987 |
pm | Start and End node in Critical Path Calculation | I have to calculate the critical path for a project, where activity A and C can start in parallel. Please see the image below
Since I had two activities that could start in parallel (A and C), I also used the dummy start node. Similarly, since my project had 2 nodes at the end (B and D), I added the dummy end node. Please tell me if my approach is correct.
| VQAonline_00054245.png |
Yes, adding start and finish milestones to the network is correct. (Calling them "dummy nodes" is unconventional, as that term is usually reserved for activity-on-arrow diagrams.)
You might want to double-check your calculations. Conventional terminology starts the project on Day 1, not Day 0. In addition, your start and finish days are not consistent with the durations shown.
| https://pm.stackexchange.com/questions/25710 |
pm | What is part of the Customer Relations team in Scrum@Scale | The Scrum@Scale guide documents a Customer Relations team as a separate entity, but does not specify what it entails.
Customer Relations, Legal / Compliance, and People Operations are
included here since they are necessary parts of organizations and will
exist as independent Scrum teams on their own, which all of the others
may rely upon.
https://www.scrumatscale.com/wp-content/uploads/Scrum@Scale-Guide.pdf @Page 16
What are the common roles/responsibilities of a CR team in Scrum@Scale? e.g. would CR also contain a sales like activity?
Why is this team not near the pentagon they relate to? As an independent Support/Implementation/Sales/Customer team, with a PO which feeds its local MetaScrum.
I guess my question really is why is it specially named and not part of the normal scaling organisation? It makes me feel you can handle it with a small team 3-9 people and does not need to scale ever.
| VQAonline_00054241.png | Customer relations typically includes everything needed to maintain relationships with existing customers and reach new customers. It tends to be focused on communication - answering questions, resolving issues or complaints, and similar types of work. It may includes sales and marketing, as well as social media and others. The exact definition varies by organization, but the Scrum @ Scale guide is showing how common functions integrate with the product development Scrum Teams at the Executive Meta Scrum / EAT level.
In Scrum @ Scale, Customer Relations (along with Legal / Compliance and HR / People Ops) are their own Scrum Teams. If you are scaling your product development teams with Scrum @ Scale, then you will likely also scale these other teams with Scrum @ Scale. All of the different team types (Product Development, Customer Relations, Legal / Compliance, and HR / People Ops) all converge at the Executive Meta Scrum and EAT levels.
Within these teams, you would continue to have a Scrum Master, a Product Owner (who wouldn't be managing a Product, but the Services provided by these organizations - perhaps it should be called a Service Owner), and a Development Team that carries out the work. If necessary, they would have Scrum of Scrums and Meta Scrum and Scrum of Scrum of Scrums and so on. However, all aspects of the organization come together at the Executive Meta Scrum and EAT.
| https://pm.stackexchange.com/questions/24526 |
pm | How can I visually represent interdependant resources? | This one may be tricky to explain, but here's the use case. Our organization aims to reduce the amount of "time-stealing" by other staff. We want to eventually see this visual indicator show less intersects, with each resource keeping as much of their available working time free from interactions with other people as possible. For example:
Person A's total available working time as a circle.
Person B who requires some of that person's time per month, so both
circles intersect the amount of time they interact.
Person C then requires a big slice of Person A and B's time.
Person D requires only a little of Person A and B's time.
How could I simply and visually represent such interconnected resource usage? I really can't think of how to visualize this, so am open to any ideas, even 3D if required.
EDIT:
Thank you for the feedback so far.
I could agree to not calling it "waste", but perhaps "shared time". Let's assume my organization is full of really capable people, who if left alone, are super-producers (ignoring reality for a while).
I played with this visualisation, which is getting closer to what I'm hoping for:
As shown, each person has their own colour (the outer line colour. The amount of time shared with another person is always of equal amount on each person's bar, represented by a fill of the shared person's colour.
Everyone has a finite amount of time, so over-sharing can be quickly spotted by those who's boxes are filled up more and the most time demanding people can be seen by their color being in most people's boxes.
This could just as easily be pie-charts, I guess. For our company's purposes, we can limit the total amount of pie or bar charts to around 15, which would still give an at-a-glance feel for the information.
| VQAonline_00054222.png | Your Question, Rephrased
Your question, as phrased, seems non-trivial. You seem to be asking how to represent process dependencies within a single infographic. There are various charts and graphs one might use to show dependencies, but if you dig a bit deeper, that's not the real underlying information that you're trying to represent here.
The information that you seem to need is one of either:
Consumption of available time by "waste" attributable to other people.
Some kind of organizational capacity chart that breaks out waste and available capacity.
Possible Representations
The number of possible graphical representations of any given data set are largely limited by your imagination. What is "best" is not answerable. However, I can certainly share some insight into what data you might need to track to represent your informational objective.
If you're looking to break out consumption, pie or donut charts are an obvious choice. Trying to pack it all into one pie chart will probably lead to information overload if you are charting more than a few people, but it's technically possible.
Consider an exploded pie chart based on the following metrics:
Resource | Available Man-Hours | Waste by A | Waste by B | Waste by C | Waste by D
Person A 40 8 18 2 5
Person B 35 6 2 1 7
Person C 38 0 6 7 7
Person D 53 1 1 1 7
The idea is that the whole pie represents the total team capacity for a given interval, while each exploded slice represents the percentage of total team man-hours attributable to each person. Each exploded slice is then sub-divided into color-coded slices attributable to waste by some other person in the data set.
If you want to show total productive/wasted hours, rather than percentages of a whole, then a stacked bar chart might be a better option. Again, the choice of format is only bounded by your communications intent.
Why You May Not Want to Do This
Processes are performed by people. It is worth considering whether interruptions or "time-stealing" are truly wasteful interactions, or whether they represent undocumented processes and procedures within your organization. Mapping undocumented processes that operate pervasively throughout an organization is a non-trivial exercise, but there are certainly practices such as value-stream mapping that may make the task manageable.
Even if you decide that the interactions truly are wasteful, you need to consider the process overhead of tracking all that information with any accuracy or for any given granularity. At one organization, I once determined that the requirement for team members to accurately track time allocations in 15-minute intervals consumed almost 50% of team capacity. Is that worth it for your use case?
You might cut down on this overhead by replacing accurate and continuous journaling with guesstimates, or by assigning values based on simplistic calculations like Waste = Wall Time - Ideal Hours to Complete. However, the Garbage In, Garbage Out principle would certainly apply.
Generally, if you want to track waste, the metrics are more meaningful at the process or project levels rather than at the individual level. However, organizational circumstances may certainly vary.
| https://pm.stackexchange.com/questions/8656 |
poker | Confusion about two pair rule in poker, can someone help me who will win |
Hello guys please help here. i think it is a draw what do you say?
| VQAonline_00054278.png | A poker hand is built with 5 cards (and no more than 5). There is no limit to how many of those cards come from your hole cards, and how many of those come from the table (community cards)
For instance, if the board comes 23456, and your hole cards are A9, you will build your hand using all 5 community cards, getting a straight.
In the situation your present, both players would get a QQJJ8 as their hand (the pair of 3's is irrelevant since any 5-card combination cointaining threes would be worse than QQJJ8). The pot is therefore split
| https://poker.stackexchange.com/questions/10603 |
poker | C Net Adjusted, What does it mean? Should it be low or high? | I am still pretty fuzzy on this concept of C Net Adjusted. The answers I read are vague and I'm just looking for a simple answer.
If C Net Adjusted is lower than C Net Won (Actual), am I doing better than I should, or worse?
As far as my understanding, if C Net Adjusted is lower than C Net Won, then you are running good. And this should be a marginal difference.
If my assumption is correct, am I also correct in assuming the stats from this run of tourny's (see image) are indicitive of a rigged poker site due to the extremely large margin between C Net Won and C Net Adjusted ?
Thanks for any help!
9 Player $5 + $0.50 NLTH (Some are regular and some are turbo.. so 10 mins blinds and 5 min blinds)
| VQAonline_00054267.png | It seems the "Adjusted" description relates to a calculation involving ICM.
Ripped direct from the PT4 forums, posted by the mod WhiteRider: (See the whole thread here)
"My C" means "My Currency", and implies a monetary stat.
"My C Net Adjusted" is your expected winnings based on the difference
in ICM values between your actual chip stack at the end of a
hand and the all-in equity adjusted chip stack you "should have had"
at the end of the hand; for all all-in hands in a tournament. This
calculation uses every all-in hand in a STT and final table hands from
MTTs where we know the complete payout structure.
With regard to your graph, this means that eventually the two lines will converge. In the short term, it's an indication of how above, or below average, your luck is.
This is as comprehensive an explanation of what it means as you'll find I believe. Direct from the developer.
| https://poker.stackexchange.com/questions/6057 |
poker | Why did i win a portion of pot in this hand? | I am the player with the hand Q♠T⋄. After the turn, I was thinking that anyone with a 4 would win the full pot. I am surprised that I won 286 of the pot. Can someone please explain how this works? I searched online, but couldn't find any explanation for this.
| VQAonline_00054270.png | TL;DR A side pot is a pot when certain players have no participation due to lacking the required amount of chips. It is the way to accept bets when players have different chips amounts. This situation can only occur when involved active players are all-in or under special circumstances in the table rules or online poker services.
Disclaimer: With such screenshot we are unable to see the whole hand history. The only possibility for you to win a pot like that is that the pot you won is a side pot. A side pot is a pot in which a player who went all-in could not participate due to not having enough chips to call an all-in bet. Take this example:
Player A bets 100 chips.
Player B calls 100 chips.
Player C wants to participate but can only call with their all-in, which is 70 chips only.
In this case, players A B C make a main pot from the lower amount of each bet: 70, 70, 70 (210 total pot). The remaining players make an additional pot for the remaining quantities: players A B make a side pot (a pot which is not the main, where every active player has equal participation) of 30 30 (60 total pot).
In the case player C wins, will only win 210 chips, and players A B will dispute their hands for the A B pot: who will win the remaining 60.
This case could also arise:
Player A bets 100 chips.
Player B calls all-in with 90 chips.
Player C calls all-in with 60 chips.
Pots: A B C (60 60 60 = 180 chips), Sidepot A B (30 30 = 60 chips), Sidepot A (10 chips, returned immediately to A after the hand resolves).
Either case, you seem to be the player A (notice how C is all-in).
| https://poker.stackexchange.com/questions/6999 |
poker | What hand is this? | I've been starting to learn poker recently (as a reference, I tend to use this list of hands). I was watching a tournament and this hand showed up.
One player has a 99, the other a JJ. I understand the JJ wins, but why does the dealer raise the K, Q & 7?
Thanks]2
| VQAonline_00054279.png | A poker hand is 5 cards, so the dealer is showing that the winning hand is JJKQ7. If, instead, the winning hand had been AhKh for a flush, the dealer instead would have raised the Qh 4h and 7h.
| https://poker.stackexchange.com/questions/10623 |
poker | Advanced Poker Calculator | Does anyone know of an advanced poker calculator for Windows?
Or for Universal Windows Platform (runs on Windows and smart phone)?
I found this for Mac Poker Cruncher. I am looking for a tool exactly like that but for Windows. I know you can use tools to host a Mac application in Windows. I am looking for a native Windows application.
Not talking about basic statistics on you versus a known hand or random hand. A tool where you can put in a range for your opponent and get an equity.
Turns out there is Equilab and Flopzilla. Toby answered in Chat.
I decided to write one. Will not have the features of Flopzilla but I want to write a phone application and this seems like good application for practice. Clearly it is not done.
| VQAonline_00054271.png | Toby Booth answered in chat
Equilab and Flopzilla
| https://poker.stackexchange.com/questions/8112 |
poker | How to count the number of starting hands in Texas Hold 'em | I'm revisiting the excellent book by Tony Guerrera, Killer Poker by the Numbers. In the first chapter he goes over how to count the number of possible starting hands but leaves, as an exercise for the reader, counting the number of starting hands that are unpaired and unsuited. He does show the probability of being dealt 2 unsuited unpaired cards as 1/110.5.
My calculation seems to be wrong and I can't figure out where I'm missing.
If you select any one of 52 cards, then there remains 36 cards left that are not of that suit or that rank. And there are 52*51 permutations of 2-card hands available.
This gives me 52*36/52*51 = 1872 / 2652 = 70.5%
I'm obviously way off here but I can't tell what I'm doing wrong.
| VQAonline_00054275.png | Probability of a pair is 3/51, because the first card dealt does not matter. Any card can pair up. The second card needs to be of the same rank as the first card. There are 3 cards left that satisfy this condition, but because one card is already dealt there are 51 cards left. Therefore the answer is 52/52 * 3/51 which is just 3/51.
Probability of no pair is 48/51. Similarly the first card does not matter, but the second card needs to not pair, which are all remaining card minus three, which is 48/51.
Probability of a suited hand is 12/51, since there are 13 cards of each suit in a deck of cards. The first card you get does not matter, but the second card needs to be of the same suit, which are 12 cards.
Probability of a non suited hand is 39/51. Same as the previous example, but now you need to essentially dodge 12 cards from the remaining 51 cards. 51 - 12 = 39.
Probability of a non suited non pair hand is 36/51, which indeed rougly equals 70.5%. Just like the previous example, but now you also need to not pair. Since these three cards are all different suits than the original cards we are not counting any cards twice, just substract three more.
Now we understand this logic we can tackle your problem. So we need to get dealt J9o. This means our first card has to be a jack or a nine, which are 8 cards total. Since there are 52 cards in a deck odds of this happening is 8/52. Now after that we need to hit the other card. There are 3 cards left that will get the job done, because suits need to be different. Odds of this happening therefore is 3/51. To calculate the odds of both these events occuring we need to multiply both numbers. We get 8/52 * 3/51 = 24/2652. We can simplify this to 1/110.5.
| https://poker.stackexchange.com/questions/9520 |
poker | What is top N% of hands in PokerStove? | In PokerStove FAQ;
The slider interface for setting the top N% of hands orders the hands
according to their preflop all-in equity versus three random hands.
This rather arbitrary selection was picked because it balances the
value of high cards with the value of drawing cards. It is not an
absolute ordering, and depending on the specific situation you may
want to edit that range of hands when doing equity calculations.
So, what is exactly N% ? Is it equal to VPIP/PFR ? How can I calculate this statistic healthy?
| VQAonline_00054264.png | To answer the question, "What is exactly N% of top hands?", there really is no correct answer as it depends on the stage of play (i.e. Preflop, Postflop) that's currently occuring. Specifically, it isn't VPIP/PFR.
Making use of these programs and hand-rankings is a matter of hand reading skill. The hand-rankings are a generalization of how a player should enumerate the plausible combinations in their opponents range according to the situation at hand.
Just as the Pokerstove FAQ mentions, hand-ranking systems are arbitrary because the nature of the game will rarely, if ever, present players with situations that conform to linear orderings of hand equity match-ups. To put it another way that's well known, "it depends"!
Looking a little deeper, there have been a number of methods used to rank hand match-ups according to differing scenarios, preflop and postflop.
Pokerstove uses, as they mention, an arbitrary measure of All-In equity vs. Three random hands. What is commonly called hot-and-cold equity, as it relates to showdown equities without any extra raises or folds involved, from any street onward. The full equity breakdown is found in a zip file through this page here: Holdem Preflop Match-Ups.
Other hand-ranking systems such as Sklansky-Karlson (aka. Sklansky-Chubukov), the inception of which is here: The Sklansky-Karlson All In No Limit Holdem Rankings I believe relate to a limited game of SB vs. BB dynamics and specifically push-fold ranges, more suited to tournament scenarios.
PokerProTools uses an "evolutionary computer simulation, whereby the set of "good hands" is gradually refined, and hands are ranked against other "good hands"". It's based on a scientific papers findings (The Challenge of Poker, Billings et al.). I've skimmed, and read over this paper a few times and, as you'd expect, it's a dense scientific piece of writing but still carries lots of insight in plain English about determining relative hand strength. This is where I found it some time ago: Towards a Meaningful Ordering of Hands
I'm sure there are more rankings systems than these, as I can recall a few being mentioned on Poker.SE already, but these are probably the most referenced versions.
I came to realise that good observation of your opponents tendencies should cause you to create detailed individualised hand-rankings based on your opponents play, and that these systems are good as starting points, but won't ever be definitive examinations of what your opponents are doing in real time.
| https://poker.stackexchange.com/questions/993 |
politics | How much "Russian money" have Russian oligarchs injected into the UK's economy and contributed to UK politicians? | The following compares statements by two very disparate British commentators, Christopher Steele and the fictional reporter Johnathan Pie.
Steele
The notes below Sky News' April 1, 2022 Beth Rigby Interviews... : Ex British spy says he can't see a way back for Putin say that "Christopher Steele ran the Russia desk at MI6". After about 08:13 Sky News' political editor Beth Rigby asks him about prominent Russians active in London's political and business scene:
Rigby: And on the issue of how the west has acted to Putin, I want to ask you a bit about the relationship between the UK and Russia. And about Oligarchs and money - Russian money in London.
In the UK for years, you were monitoring Russia and the misdeeds of its spies like murdering people in the UK. And yet you also saw politicians and businessmen; they'd go into parties and holidaying with oligarchs. Do you think that the establishment here let themselves get seduced?
Steele: Absolutely. I think there were two things going on there. One is an element of naivety, because many of the Russians who come to London are very urbane, very convincing, very sort-of westernized. They don't represent the "real Russia" if you like. There is a dark side to Russia which not many people understand. Sadly I've been studying it for the last 20 years.
But I also think in addition to that, Russian money -- a wall of money that hit London; it wasn't just Russian but it was Russian money first I think -- sort-of set up a lobby, a group of interests who serviced this elite, who... the lawyers, the estate agents, the PR firms, and so on. And it became a pretty important part of our economy. And I suspect, also in terms of investment and so on, particularly after Brexit and what have you when we were looking for other forms of investment in the country.
This golden visa scheme which is now so controversial and in retrospect was such a bad mistake, grows out of that problem.
and in response to Rigby's questions about Evgeny Lebedev being "nominated for a life peerage by UK prime minister Boris Johnson" and and about other prominent Russian business people operating in London:
Steele: ...this is such a controversial appointment, and the story out there is that it was against the advice of the security services, so I think it's a pretty exceptional case. And there was a debate in Parliament the other day and I think probably the outcome of that should be more transparency.
Rigby: You have some experience, would you think that that has credibility; that the security services would have been anxious about this appointment?
Steele: I think any sort-of family member of a former KGB officer or a KGB agent -- and actually Lebedev is not the only one, there are quite a few former KGB officers who are quite prominent in Britain and in business here who need to be very closely looked at. And certainly it's surprising to me that the've managed to operate in the country in the way that they have.
Pie
From the New York Times; March 11, 2022 Opinion video Jonathan Pie: How Putin Weaponized London’s Greed | NYT Opinion after 00:26:
Pie: I don't really know what to say. For the first time in my career, there are no words or explitives that can do this situation justice.
and that not being very likely, he goes on to say
Here in the UK, we don't have quite the same problem. Only five percent of our gas comes from Russia. Here we're reliant on something far more precious -- Russian money.
For 20 years, Putin has been using illicit money to fund an oligarchy of billionaires to keep his corrupt regime in power. And for 20 years, those Kremlin-approved oligarchs have been coming here to "invest" their ill-gotten gains via a loophole that allows people to buy property in the UK anonymously.
[...] Welcome to Londongrad, Moscoow-on-Thaimes. Eighty-seven thousand homes in Britain were bought through off-shore companies by anonymous millionaires. At least 1.5 billion1 pounds' worth of those are owned by Russians with direct links to the Kremlin.
[...] We have let it happen for years, because it's because it's how the UK makes its money. It's the only industry we have left.
[...] Speaking of Boris Johnson, he's up to his (ears) in it as well. Since he became prime minister, Tories have accepted 2 million pounds in Russian donations. I know in American terms, 2 million is the political donation equivalent of tipping the bellboy, but here we're much more strict. We put a limit on the amount of dirty, illegal, kleptocratic money that our main political parties can take, which has an upside for Putin because it means British politicians are incredibly cheap to buy.
In 2020, 14 members of Johnson's government received Russian cash. The Tory party chairman even runs a luxury concierge service that helps oligarchs buy property in London.
Question:
How much "Russian money" have Russian oligarchs injected into the UK's economy and contributed to UK politicians? Pie offers some bits and pieces but at this point in time surely some authoritative source has compiled at least a rough enumeration.
1"billion pounds" Somebody help me here; is that one thousand million or one million million? update: comment suggest one thousand million.
| VQAonline_00054445.png | It's very difficult to put an absolute figure on this. Firstly, it's important to differentiate between Russian investment in the UK & Russian donations to politicians. In the first case, Walker's character appears to be referencing a February 2022 report by anti-corruption organisation Transparency International, which presents the £1.5 billion figure, based on figures from June 2021:
£1.5 billion worth of property was bought by Russians accused of corruption or links to the Kremlin.
Nearly £430 million worth (28.3% by value) is in the City of Westminster, while £283 million (18.8%) is in Kensington and Chelsea. A more detailed breakdown can be found below.
Analysis of how this £1.5 billion is owned reveals £830 million worth (55% by value) is held by companies in Britain’s Overseas Territories and Crown Dependencies. The secrecy provided by these offshore financial centres is often used by those seeking to hide their ownership of assets.
It's not clear that this represents the whole picture, however. The House of Commons Library's April 1st 2022 report, Countering Russian influence in the UK, notes that putting an exact figure on the amount of Russian investment in the UK is impossible due to "the difficulty in tracing the beneficial (ultimate) owners of some assets", but estimates that it totals "tens of billions". Vladimir Ashurkov of the Anti-Corruption Foundation told the Foreign Affairs Select Committee in 2018 (Question 98) that "there have been some estimates of money coming from Russia to Britain over the last 20 years—100 billion is probably a good number. Most of that money is legitimate; I think only a fraction of that is the proceeds of corruption and crime."
This is borne out by the number of investor visas issued to Russian applicants - the Tier 1 investment visa granted permission to stay in the UK for up to 5 years in return for a minimum investment of £2 million until it was ended in February 2022. The Commons Library report gives a figure of over 2,500 of these visas having been issued to Russian applicants, representing at least £5 billion of investment. The report by the Intelligence and Security Committee on Russia gave the following explanation for the Government's promotion of the scheme:
The UK welcomed Russian money, and few questions – if any – were asked about the provenance of this considerable wealth. It appears that the UK Government at the time held the belief (more perhaps in hope than expectation) that developing links with major Russian companies would promote good governance by encouraging ethical and transparent practices, and the adoption of a law-based commercial environment.
As far as direct donations to politicians and political parties go, however, it's possible to be a little more precise. The figure that has been reported in the last few weeks, ~£2.3 million in donations to the Conservative Party since Boris Johnson became leader, is based on calculations made on figures published by the Electoral Commission - predominantly donations made by Lubov Chernukhin, Alexander Temerko, and Mohamed Amersi, of £700,000, £357,000 and £258,000 respectively. On the other hand, the Labour party has received more than £1 million from financier Martin Taylor, whose Nevsky Fund has major investments in Russia.
Under UK law, all donations must be reported to the Electoral Commission and all donations to candidates over the sum of £50 must come from an individual on the UK electoral register - essentially, if you can vote for a party, you are eligible to donate to it. The argument that has been put forward by the recipients of these donations is that if a voter is on the electoral register, they can hardly be described as a 'Russian oligarch'. It's almost impossible, however, to definitively determine the ultimate source of money donated, even if the last stop is a permissible source. The result is often spurious but eye-catching headline figures obtained by journalists scouring the register for donations made by British individuals with Russian-sounding names, and it remains incredibly difficult to accurately trace the initial source of any donated wealth.
| https://politics.stackexchange.com/questions/72297 |
politics | Lawful for some English public hospitals to stock more kinds of medications than others? | Left to right – Guy's, Cambridgeshire, Salisbury, Oxford.
How's it legal for NHS trusts to have different formularies?
Assume you live in Cambridge, but your migraine can be only treated with a triptan on Oxford's formulary, but not Cambridgeshire's, like Eletriptan. What do you do? Must you go to a NHS hospital in Oxford?
I don't want to cram too many pics in the collage, but Southampton has Almotriptan, Sumatriptan and Zolmitriptan, but Herefordshire just the latter two.
| VQAonline_00054389.png | There is no legislative requirement for individual hospitals, primary care facilities or secondary care facilities to provide the same treatments or specific level of care across NHS England, but there are legislative requirements to reduce the inequalities in healthcare across the NHS.
The Health and Social Care Act 2012 introduced general legislation requiring the NHS to reduce the effects of healthcare inequality, but it does not go into specifics such as requiring all hospitals to fund the same treatments.
As a result, patients have a legal right to choose where to receive treatment in secondary care facilities (ie, hospitals) once they have a referral, but no specific right to choose any GP they wish (GP surgeries have specific catchment areas, outside of which they can refuse you as a patient - hospitals in England have no such limitations and can only refuse you if they do not provide the treatment you are seeking).
Part of the point of splitting up NHS England into various Clinical Commissioning Groups (the descendant of Primary Care Trusts, which ceased to exist in 2013) is that healthcare requirements are not the same across the country, and some areas need more funding in certain healthcare areas than others. Requiring the same level of care for all healthcare issues across the board all over the country would mean some areas are underfunded for some outcomes and overfunded for others.
In short, you need a referral to a specialist from your GP, and then you can choose to go to a hospital in a CCG which funds the treatment you are seeking. This may not always work, as the treating CCG can request the referring CCG to fund the work and thus you may be rejected anyway. You also have the option of funding the drugs yourself.
| https://politics.stackexchange.com/questions/47864 |
politics | Today, 6 Jan 2021, Twitter deleted three tweets by Donald Trump. What did they say? | What did the three tweets say?
| VQAonline_00054422.png | All of Donald Trump's deleted tweets and retweets can be found here on factba.se, which is a site that tracks what Trump and other political figures say or tweet.
You can see screenshots of the original tweets on that site. Here are the transcripts of the regular tweets:
Mike Pence didn't have the courage to do what should have been done to protect our Country and our Constitution, giving States a chance to certify a corrected set of facts, not the fraudulent or inaccurate ones which they were asked to previously certify. USA demands the truth!
These are the things and events that happen when a sacred landlside election victory is so unceremoniously & viciously stripped away from great patriots who have been badly & unfairly treated for so long. Go home with love & in peace. Remember this day forever!
And the transcript of the video he posted:
I know your pain. I know you’re hurt. We had an election that was stolen from us. It was a landslide election, and everyone knows it, especially the other side, but you have to go home now. We have to have peace. We have to have law and order. We have to respect our great people in law and order. We don’t want anybody hurt. It’s a very tough period of time. There’s never been a time like this where such a thing happened, where they could take it away from all of us, from me, from you, from our country. This was a fraudulent election, but we can’t play into the hands of these people. We have to have peace. So go home. We love you. You’re very special. You’ve seen what happens. You see the way others are treated that are so bad and so evil. I know how you feel. But go home and go home at peace.
Twitter's TwitterSafety account stated that they removed these tweets for repeated violations of their policies that went above their usual public-interest policy which allowed other violations to go undeleted. His account is locked until the tweets are deleted, with a minimum 12-hour suspension, and it may be suspended if he continues to break their policies.
| https://politics.stackexchange.com/questions/61468 |
politics | Can a President mandate Upvotes? | This image is from when Barack Obama (the then serving president) thanked Reddit for helping protect the open internet.
Thanks Redditors! Wish I could upvote every one of you for helping
keep the internet open and free!
My question, if this was taken at face-value, and the President really wanted to force a private company to help him apply a blanket Upvote to everybody on Reddit, why could/can't he, and what would he have to do to accomplish this?
I'm pretty sure this isn't allowed by Reddit's policies given it's a form of "vote cheating" (albeit the rules are oddly shaky for a blanket Upvote).
I know realistically nothing about the extent of power a President has over the functions of a private company, so I was hoping someone could break down the various methods the President could go about giving an Upvote to every user on Reddit.
I would prefer answers that avoided simply asking nicely (given not every President has had the same rapport with the company behind Reddit so lets assume they don't want this to happen) and instead focused on the steps and barriers the President would face before being provided with a hopefully enormous glorious green button. Or, if such an mandate is actually legally impossible given the checks and balances I've heard about.
| VQAonline_00054347.png | A president has the power, under the general terms of Article 2, to instruct the various federal agencies how to act, and how to spend the money that they already have. Any such order is then subject to scrutiny by Congress and the SCOTUS.
The ability of the President to instruct a private company is limited. In 1952, with a steel strike threatened, President Truman signed an order renationalising the steel mills. This was overturned by the Supreme Court (Youngstown Sheet & Tube Co. v. Sawyer), who ruled that even though the President had legitimate national security concerns (steel was essential for the Korean war effort), he lacked the authority to do so. The court decided that there are limits to what the constitution calls "executive power", and that seizing property is beyond that limit.
In this case of upvoting all redditors, the president is not attempting to take complete control of a private company, but he is attempting to exert authority over a company to act in a way other than what they see as their best business practice. And the indication of Youngstown Sheet & Tube Co. v. Sawyer is that the President lacks this power.
However, the president would be free to create a Department of Reddit Upvoting and get federal employees to log onto Reddit and start upvoting everyone. That would be the President directing the executive how to act. Congress would be able to review this and prevent it by refusing to fund such a department, or simply overruling the order.
The President also has various tools that he could use to put pressure on a private company. He can make business difficult for a company while "asking nicely": "Give a upvote to everyone and I won't send the IRS round to audit your books every Monday" but probably less crude. The president has a lot of soft power so a bit of carrot and stick might well be the best strategy.
| https://politics.stackexchange.com/questions/26027 |
politics | Can a country withdraw from a free trade agreement (NAFTA)? | The North American Free Trade Agreement (NAFTA) was established in 1994, with support from the national governments of Canada, the United States, and Mexico.
If one of these governments suddenly wanted to, could they withdraw from NAFTA? Or could they force a member of NAFTA, perhaps Mexico, to leave?
| VQAonline_00054306.png | Each free trade agreement sets the terms, so the answer will vary by FTA. In the case of NAFTA, the terms of withdrawal are dictated in Article 2205. Specifically:
Article 2205: Withdrawal
A Party may withdraw from this Agreement six months after it provides written notice of withdrawal to the other Parties. If a Party withdraws, the Agreement shall remain in force for the remaining Parties.
The 6 month written notification is fairly standard for most international agreements, free trade or otherwise.
Article 2205 also answers whether or not a country can force another out: No.
If one country were to leave NAFTA, the others would still have the agreement, at least nominally, but if that country were the U.S., Mexico and Canada would have a hard time making NAFTA worthwhile.
The U.S. could, in theory, agree to leave NAFTA at the same time as Canada, and then immediately resign an identical treaty with Canada, which would have the effect of kicking Mexico out. The realities of politics in both countries make such a course of action unlikely, as once the treaty is open for renegotiation, then interest groups in both countries would want to seek better terms than they got 20 years ago.
| https://politics.stackexchange.com/questions/10739 |
politics | In CBC's poll tracker, why do the probabilities of winning not add up to 100%? | In CBC's poll tracker at: https://newsinteractives.cbc.ca/elections/poll-tracker/canada/, probabilities of winning the 2019 Canadian federal election are provided.
Currently, these are 11% Liberal majority, 39% Liberal minority, 42% Conservative minority, and 6% Conservative majority. By my count, these probabilities add up to 98%. Shouldn't this be 100%?
| VQAonline_00054386.png | I don't see any explanation on their Full Methodology Info page, but when percentages don't add up to 100%, the usual answer is that it's due to rounding, so 11% might actually be 11.4%, which was rounded down to 11. Among 4 options, rounding could explain almost all of the missing 2%.
Another possibility, is that these 4 options don't represent all possibilities. For example, it's possible that the Liberals and Conservatives get equal numbers of seats, but neither has a majority (due to seats gained by other parties)
| https://politics.stackexchange.com/questions/46667 |
politics | How do I interpret this table of the number of UK bills for the session 2016-2017? | Does the following table mean that 6 of 33 bills that were passed in that year, originated in the House of Lords?
Source.
| VQAonline_00054351.png | Yes.
As noted here:
Bills are introduced in either the House of Commons or House of Lords for examination, discussion and amendment.
Although most government bills are introduced in the House of Commons (HoC), parliamentary time is a scarce resource, and for reasons of scheduling bills are sometimes introduced in the House of Lords (HoL) instead. The bill must still be debated in and passed by the HoC at a later stage.
For example, scrolling down past the first page of the document in the OP, we can see one of the 6 bills introduced in the Lords was the Bus Services Bill, which eventually became the Bus Services Act 2017.
The government must be able to command a majority in the HoC; but it also has a presence in the HoL, through members of the HoL who are affiliated to the governing party or parties. The Leader of the Lords is a Cabinet minister specifically responsible for managing government business in the HoL. (He or she has a counterpart in the HoC, who surprisingly enough is known as the Leader of the Commons.)
| https://politics.stackexchange.com/questions/26398 |
portuguese | "Nós ossos que aqui estamos pelos vossos esperamos" - não deveria ter uma vírgula? | Na entrada da Capela dos Ossos, em Portugal, há a seguinte frase:
Nos ossos qve aqvi estamos pelos vossos esperamos
Para dar mais contexto à mensagem, aqui está uma breve explicação encontrada na Wikipédia:
Foi construída no século XVII por iniciativa de três monges franciscanos que, dentro do espírito da altura (contra-reforma religiosa, de acordo com as normativas do Concílio de Trento), pretendeu transmitir a mensagem da transitoriedade da vida, tal como se depreende do célebre aviso à entrada: "Nós ossos que aqui estamos pelos vossos esperamos".
Ler essa frase me parece estranho, sinto a falta de uma vírgula (ou duas). O português mudou bastante do século XVII para cá, e por isso estou em dúvida se isso é apenas uma variação da língua ao longo do tempo. Imagino que a frase pudesse ser escrita das seguintes maneiras:
Nós ossos que aqui estamos, pelos vossos esperamos.
Nós, ossos que aqui estamos, pelos vossos esperamos.
Realmente faltam vírgulas na frase original? Se sim, ambas opções acima seriam corretas? E, como bônus, essa necessidade da vírgula é realmente recente ou não se encontra na entrada por outros motivos?
| VQAonline_00054482.png |
Realmente faltam vírgulas na frase original? Se sim, ambas opções acima seriam corretas?
Se considerarmos
"ossos que aqui estamos" como um aposto explicativo, deve estar separado por pontuação do restante da frase, portanto opção 2 é a correta.
"nós ossos" como o sujeito e "que aqui estamos" como uma oração subordinada adjetiva explicativa, deve estar separada por vírgulas do restante da frase, portanto a opção 2 é a correta.
"nós ossos" como o sujeito e "que aqui estamos" como uma oração subordinada adjetiva restritiva, não pode ser separada por vírgulas do restante da frase, portanto está correta a frase original.
As três interpretações são aceitáveis a meu ver, então concluo que, haja vista a última interpretação, não deveria ter uma vírgula obrigatòriamente, embora a opção 2 também seja aceitável.
| https://portuguese.stackexchange.com/questions/8953 |
portuguese | Qual é o nome dumas saliências transversais nas lombadas de alguns livros de capa de couro? | Muitos livros antigos encadernados a couro têm umas coisas salientes atravessadas nas lombadas, que eu assinalei na figura abaixo. Aquilo é os fios que unem as folhas que passam por baixo daquilo. Mas qual é o nome daquilo?
| VQAonline_00054472.png | Um termo que encontrei foi nervura:
Segundo a Infopedia: saliência transversal na lombada dos livros encadernados
Neste artigo é mencionando, na página 4 do PDF, vários significados de "nervura", entre eles: Na tipografia, "nervura" se refere à saliência transversal das lombadas dos livros encadernados.
No livro intitulado "Livro" (Michel Melot), há também uma referência ao termo nervo:
No passado, as encadernações dos livros eram mantidas por um sistema complicado de fios cosidos sobre os cadernos, o que os deixava salientes no dorso. Estas saliências dos nervos marcavam linhas horizontais paralelas, deixando-as bem visíveis sob a cobertura do couro. As técnicas de encadernação há muito tornaram desnecessárias estas saliências, as quais, entretanto, continuam marcadas por aquilo que os encadernadores chamam de "falsos nervos".
| https://portuguese.stackexchange.com/questions/4708 |
portuguese | "Cada empresa tem o valor que merece ser negociado" - isto está correto? | Estou lendo um livro e achei a frase:
Cada empresa tem o valor que merece ser negociado.
Eu escreveria:
Cada empresa tem o valor que merece ser negociada.
em concordância com "cada empresa".
Fiz uma pesquisa rápida no Google, e não achei nada. Apesar de adorar português, sempre erro algo, aqui, ali!
Estaria o livro correto?
==
Completo
Fonte: https://www.amazon.com.br/Valuation-Precificar-A%C3%A7%C3%B5es-Alexandre-P%C3%B3voa/dp/8535253750
| VQAonline_00054483.png | A frase está gramaticalmente correta. Se faz sentido no contexto, é que eu não posso dizer, porque não tenho o contexto. Uma maneira intuitiva de desmontar a frase é assim:
Cada empresa tem o valor.
Qual valor?
O valor que merece ser negociado.
O constituinte que merece ser negociado é uma oração subordinada adjetiva restritiva que modifica o nome valor, e o valor que merece ser negociado é o complemento direto de tem.
A alternativa que tu propões ― “cada empresa tem o valor que merece ser negociada” ― é que é muito estranha; por duas razões. Nesse caso, a empresa é que merece ser negociada, mas a ordem dos termos é estranhíssima, porque a oração subordinada (a negrito) fica separada do nome que modifica; o normal seria:
Cada empresa que merece ser negociada tem o valor
Depois, a empresa tem o valor? Qual valor? Na frase original, nós sabemos que é o valor que merece ser negociado.
Há casos em que a tua questão realmente se põe. Por exemplo, as duas frases seguintes estão corretas:
(a) Comprei um banco de madeira muito rara.
(b) Comprei um banco de madeira muito raro.
Em (a), a madeira é que é rara (à parte disso, o banco pode nem ter interesse; podemos querer desmontá-lo e aproveitar a madeira para outra coisa); em (b) o banco, que até pode ser de madeira barata, é que é raro. Repara que, ao contrário da tua alternativa, muito raro/a fica em qualquer dos casos junto ao nome que modifica, só madeira em (a), banco de madeira em (b).
| https://portuguese.stackexchange.com/questions/9331 |
portuguese | Regência do verbo lembrar - comentando um post na rede social Linkedin | Vi a frase a seguir na rede social Linkedin.
Quando fui fazer um comentário e fiquei com dúvida na regência do verbo lembrar.
Exemplo:
I) Tem razão, é bom lembrar-se dessa liberdade :). Para nos fazer esquecê-la existem muitas pessoas.
II) Tem razão, é bom lembrar dessa liberdade :). Para nos fazer esquecê-la existem muitas pessoas.
III) Tem razão, é bom nos lembrar dessa liberdade :). Para nos fazer esquecê-la existem muitas pessoas.
IV) Tem razão, é bom lembrar essa liberdade :). Para nos fazer esquecê-la existem muitas pessoas.
Qual seria a melhor opção? Por quê?
| VQAonline_00054470.png | Lembrar tem muitas regências possíveis. As regências ideais dependem do que queres dizer exatamente. Apresento aqui as que me parecem relevantes para a tua pergunta.
1. ‘manter na memória, pensar em’―lembrar algo:
(IV) é bom lembrar essa liberdade
é bom lembrarmos essa liberdade
Portanto aqui estarias dizer, por exemplo, que as pessoas que mantêm na sua mente a liberdade tiram daí prazer, ou que é bom para a sociedade que nós mantenhamos a liberdade nas nossas mentes, ou até que é um dever nosso manter a liberdade nas nossa mentes.
Encontramos esta regência para este sentido em vários dicionários:
lembrar bons momentos/a infância (Aulete 1)
Lembrou o tempo em que vivia no Rio (Michaelis 2)
lembravam a figura do João com saudade (Houaiss, Lisboa, 2003)
2. Parecido com o anterior, mas com mais ênfase em ‘não esquecer’ ou em ‘trazer à ideia, à atenção consciente’―lembrar-se de algo:
é bom nos lembrarmos dessa liberdade / é bom lembrarmo-nos dessa liberdade
É também possível é bom lembrar-se dessa liberdade para dar um conselho a alguém:
(I) é bom [você/o senhor] lembrar-se dessa liberdade
Exemplos com esta regência e sentido:
já não se lembrava de onde tinha posto a chave (Aulete 1)
Como vai a senhora, dona Alice? Lembra-se de mim? (Michaelis 2)
Eu encontro com este sentido no Google Books lembrar de algo (II, “é bom lembrar dessa liberdade”). A mim soa-me estranho, porque é uma regência que não se ouve em Portugal. Também não a encontro nos dicionários. Poderá ser uma regência que seja aceite apenas coloquialmente no Brasil.
3. ‘chamar a atenção a alguém para’―lembrar a alguém algo ou lembrar alguém de algo:
é bom [você] nos lembrar essa liberdade
(III) é bom [você] nos lembrar dessa liberdade
Lembrar alguém e lembrar a alguém ficam iguais quando o alguém somos “nós”. Aqui estarias a dizer que foi bom que a pessoa que postou a mensagem nos tivesse lembrado a/da liberdade. A minha primeira impressão foi que não era este o sentido que pretendias, pois a frase não me soava muito bem sem explicitar o sujeito que lembra. Mas vendo melhor o contexto, provavelmente até é mesmo isto que queres.
Já temos uma pergunta sobre a regência nesta aceção: lembrei ao João o seu dever / lembrei o João do seu dever. Exemplos das duas regências neste sentido:
lembrar a alguém algo
O rapaz lembrou ao pai o trato que haviam feito (Michaelis 1)
lembrou ao marido que a conta de luz tinha que ser paga (Aulete 4)
lembrar alguém de algo
Lembrou o empregado de suas obrigações (Aulete 3)
Lembrei-o do documento que tinha que assinar (Aulete 4)
Eu foquei aqui apenas as aceções que me parecem relevantes para os teus exemplos e contexto. Lembrar pode ser usado com várias outras conotações. Nesta pergunta sobre lembrar vs recordar encontras uma discussão mais abrangente, mas naturalmente não dirigida à tua pergunta em particular.
| https://portuguese.stackexchange.com/questions/4391 |
portuguese | What does "CONCOC" stand for? | I wanted to check if "Concoc" was already a word or a brand name for anything, and it seems it is used in Brazillian videos, but I can't find it in a Portuguese dictionary.
Does CONCOC mean anything?
I don't speak any Portuguese so I can't deduce the meaning from context.
| VQAonline_00054474.png | Concoc is a brand in Brazil. They are schools around the country. Usually, they give scholarship, so, these videos are tips to the test for scholarship.
Here part of a news about it:
O aulão CONCOC ocorre no Cinesystem do Shopping Iguatemi, em
Florianópolis, das 8h às 12h. Das 14h às 17h, do mesmo dia, será
aplicada uma prova de conhecimentos gerais, na sede do COC, para os
alunos concorrerem a bolsas de estudo na unidade. Todos os
participantes da prova ganharão descontos na mensalidade do ensino
médio.
In a quick and free translate: A class preparation for scholarship happened.
Source: AO VIVO: assista ao Aulão CONCOC em parceria com DC neste sábado
| https://portuguese.stackexchange.com/questions/5673 |
portuguese | Como se chama a parte da lata que serve para a abrir? | “Todas” as latas de refrigerante têm uma certa parte, no topo, que server para empurrar a aba, e abrir a lata. Como se chama essa parte?
| VQAonline_00054455.png | Em Portugal o nome dado a essa parte da lata é anilha de lata.
| https://portuguese.stackexchange.com/questions/277 |
portuguese | Qual é a diferença entre «símbolo» e «emblema»? | Estava a falar sobre futebol e disse:
...já para não falar do símbolo do Benfica1, que monocromático fica
feio.
E alguém me veio corrigir:
Símbolo não, emblema. Os símbolos são Coluna, Eusébio, Bento,
Chalana,...
Pelo que pesquisei parece que são sinónimos, mas na priberam não faz nenhuma referência a isso.
Será um regionalismo? São sinónimos ou são diferentes?
1 - Imagem do Simbolo/Emblema do SLBenfica
| VQAonline_00054475.png | "Símbolo" é um termo mais amplo - por exemplo, não apenas o emblema, mas também seu uniforme é um símbolo do clube.
"Emblema" é o símbolo oficial do time, sua insígnia, divisa, marca, distintivo, mas apenas um dos símbolos do clube, como fica claro em sua página:
O Emblema do Benfica é, sem dúvida alguma, a sua imagem de marca. Tal como a maior parte das tradições e símbolos do Clube, o emblema foi elaborado entre 13 de dezembro de 1903, quando surgiu a ideia de criar o Clube e a data da sua fundação, a 28 de fevereiro de 1904.
Nesse sentido, "símbolo" não é incorreto, mas "emblema" de fato pode ser preferível por ser mais específico.
| https://portuguese.stackexchange.com/questions/6012 |
puzzling | Rosetta Stone puzzle | The answer to this puzzle is one word.
| VQAonline_00055659.png | The first line shows
lots of threes.
The second says
$\left(\frac{2838}{43\cdot\sqrt{36}}\right)^3-\frac{23}{360}\cdot\left(\frac{238}{34}\right)!$
in
$\left(\frac{\textrm{Greek}}{\textrm{Khmer}\cdot\sqrt{\textrm{Armenian}}}\right)^?-\frac{\textrm{modern Western}}{\textrm{Chinese}}\cdot\left(\frac{\textrm{Hebrew}}{\textrm{Indian}}\right)!$ numerals
yielding
1009
which
in Roman numerals, which we haven't used yet, gives MIX.
Confessions:
I don't know what the ? is, but it's clearly 3 (1) just from looking at it and (2) because it appears on the first line, which is all threes. I'm not sure whether "Armenian" is right. The thing I've labelled as Khmer seems like the first figure is Khmer and the second is Thai. I am not an expert on any of this stuff.
| https://puzzling.stackexchange.com/questions/72638 |
puzzling | The Tripan Balance |
The tripan balance is used for comparing different weights. For example, when the pans carries 7 balls,5 balls and one is empty. The heaviest tilt to lowest level while the empty pan is at the highest level. In case of the same number of balls on two pans, both pans tilts to same level.
Twelve solid balls looks identical but two of them is either lighter or heavier (say 1% different to normal balls). Trying the tripan balance, how much checkings will it takes to find out the odd balls?
| VQAonline_00055967.png |
It's easy to do in 3 weighings. Just put 4 balls on each plate to start. If all three plates are at different heights, then you know the top plate has the light ball and the bottom plate has the heavy ball. Take the 4 in the top plate and put 3 of them individually into a plate. If one plate is light, there is the light ball. If not, it's the one you left out. Do the same for the heavy ball, and you're done in 3 weighings (4x4x4, 1x1x1, 1x1x1).
Otherwise,
the plates will be at the same height after the first weighing. This means that the heavy and light ball are together. Note which group each ball was in (mark them with 3 colors, for example), and rearrange them into 4 groups of 3, with each new group containing one ball from each of the original groups. Now put 3 of the new groups on plates. We know that the light and heavy ball are split up, so the plates cannot be at the same height. If one plate is light, then the light ball is there and the heavy ball is on the table. If one plate is heavy, then the heavy ball is there and the light ball is on the table. If the plates are all different heights, then you know where the light and heavy ball are.
In any event,
we now know which group of 3 has the light ball, and which has the heavy ball. Pick one of those groups (say the heavy group) and put each of its balls on a plate. This will give you the heavy one, but also the light one - it's just the ball in the light group that has the same marking as the heavy ball. 3 weighings total (4x4x4, 3x3x3, 1x1x1).
| https://puzzling.stackexchange.com/questions/87174 |
puzzling | Do your best! (I can't really say no pressure) | FROM:
(-)(- -)(> • -)(- • - •)(- - - - -)(- - - - - -)(> • - - - - -)(- - - - - - - -)(- - - - - - - - -)(> • - - - - - - - •)
6 4 2 1 3 5
TO:
What's the answer to this puzzle?
Note: The brackets are just there to seperate them from each other... they're not needed once you realize what this puzzle is about.
| VQAonline_00056742.png | The upper diagram
is, once line breaks are introduced in the obvious places, an upper portion of Pascal's triangle. Each "•" represents one number from the triangle; each ">•" represents two numbers, the first always being a 1, concatenated to form a 2-digit number in base 10. Reading these in order of the numbers below them, we get PASCAL.
The lower diagram is
is simply a triangle, so to get FROM the upper TO the lower we need to remove PASCAL. So perhaps the title shouldn't say "no pressure" after all. (The pascal is the SI unit of pressure.)
It's not quite clear to me whether
"the answer" is meant to be PASCAL or NO PASCAL or even NO PRESSURE. :-)
| https://puzzling.stackexchange.com/questions/118068 |
puzzling | 4x4 grid equations | Can you place all numbers from 1 to 16 into cells, such that the following 8 equations hold? Note that the operator "/" only works for non-remainder division, i.e. you can have "8 / 4" but not "8 / 3". As usual multiplication and division are performed before addition and subtraction. Good luck!
| VQAonline_00056366.png | I think the answer is
$$\begin{array}{ccccccc}9 & + & 16 & \div & 8 & = & 11 \\+&&-&&-&&+\\6 & \div & 3 & + & 12 & = & 14 \\\times&&\times&&\div&&\div\\1 & + & 2 & + & 4 & = & 7 \\=&&=&&=&&=\\15 & - & 10 & \div & 5 & = & 13\end{array}$$
(Partial) Explanation:
Let's label the grid as follows:
$$\begin{array}{ccccccc}A & + & B & \div & C & = & D \\+&&-&&-&&+\\E & \div & F & + & G & = & H \\\times&&\times&&\div&&\div\\I & + & J & + & K & = & L \\=&&=&&=&&=\\M & - & N & \div & O & = & P\end{array}$$
Observe that there are five divisions, none of which share any number. Since all numbers are distinct, the ratios must be at least 2, and therefore the divisors cannot exceed 8. The positions for divisors are $C, F, K, L, O$. Also since $I+J+K=L$, it follows that all of $I,J,K$ are less than $L$, and therefore they cannot exceed 8 either. So far, we've identified seven cells that cannot exceed 8: $C, F, I, J, K, L, O$. Also, if you're familiar with Kakuro, you can notice that 1 must be one of $I,J,K$ from $I+J+K=L \le 8$.
Now consider the two prime numbers 11 and 13. They cannot be a part of division (neither dividend nor divisor): They cannot divide anything else and they cannot be divided by anything else other than 1. The only place where 1 can divide something is $G \div K$, but then $C$ becomes too high. Therefore, 11 and 13 must be placed in $ADPM$.
Also note that $A \rightarrow D \rightarrow P \rightarrow M$ forms a strictly increasing sequence with gaps of at least 2, since the quotients are at least 2 and
$$\begin{align}A + B \div C &= D \\D + H \div L &= P \\P + N \div O &= M\end{align}$$
So 11 and 13 must be adjacent in the sequence. If they're assigned to $AD$, $M$ gets too large, so the only options are $D=11, P=13$ or $P=11, M=13$.
At this point, combined with the information that $HL$ can only be one of $(12,6),(14,7),(16,8)$, I started brute-forcing the cells, and I was lucky that I guessed the 3rd row and 4th column correctly early on.
As a bonus, a computer-based proof that the solution is unique (Python + Z3Py):
import z3
solver = z3.SolverFor('QF_FD')
varlist = [z3.Int(var) for var in 'abcdefghijklmnop']
for var in varlist:
solver += 0 < var
solver += var <= 16
solver += z3.Distinct(varlist)
a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p = varlist
solver += b == c * (d - a)
solver += e == f * (h - g)
solver += l == i + (j + k)
solver += n == o * (m - p)
solver += m == a + (e * i)
solver += n == b - (f * j)
solver += g == k * (c - o)
solver += h == l * (p - d)
assert solver.check() != z3.unsat
model = solver.model()
for var in varlist:
print(model.eval(var), end=' ')
print()
solver += z3.Or(*[var != model.eval(var) for var in varlist])
assert solver.check() == z3.unsat
print('No more solutions')
Output:
9 16 8 11 6 3 12 14 1 2 4 7 15 10 5 13
No more solutions
| https://puzzling.stackexchange.com/questions/102658 |
puzzling | A circle touches two sides of a triangle and two of its medians | A circle touches two sides of a triangle and two of its medians. Prove that the triangle is isosceles.
This problem came from the Mathematical Digest issue 62 (Jan 1986) which in turn cited a Russian mag called KVANT (meaning "Quantum").
| VQAonline_00056479.png |
As the triangles ADC and BEC have the same incircle and their areas are equal (half that of ABC), so are their perimeters
DC+DA+AC = EC+EB+BC
or, subtracting from both sides CD+CE+DA+EB
AE-EB = BD-DA.
This means that D and E lie on the same pair of hyperbolas with foci A and B. Since they also have the same distance to the base AB (half that of C) the triangle must be isosceles by symmetry.
| https://puzzling.stackexchange.com/questions/107801 |
puzzling | A Chess Lock Puzzle? | I was recently talking to one of my friends who played chess (much better than me, I'll admit). He said he had a different kind of chess problem, one that may be a little easier, or that may be a little bit harder than usual. He said it was a chess lock puzzle.
He then grabbed two(!) chess sets and set up the following position:
He challenged me to find the least number of moves to capture the black king, using the following rules:
White gets an infinite number of moves.
White may only capture undefended pieces, and the black king (checkmate isn't a thing, just capture the black king)
Rooks are the only keys that work. You must capture the black king with a rook.
He said his best was to do it in 17 moves. Can you do it quicker?
| VQAonline_00055702.png | I think there's a quicker way to do it.
Rb2 Nb1 Rd2 Bd1 Rf2 B3e2 Rf4 Bgf3 Rg4 Rxg7 Rg8 Rxa8
for 12 moves.
| https://puzzling.stackexchange.com/questions/74522 |
puzzling | Puzzling Pieces of Pumpkin Pi |
You bake a nice, delicious-looking pumpkin $\pi$, cut it into 6 slices and serve it on your table. As a fan of numbers, you label each slice with numbers from 1 to 6.
Feeling very pleased and satisfied, you go back into your kitchen to grab a glass of water. Once you get back to your table, instead of finding your pumpkin $\pi$, you find a piece of paper with a pumpkin $\pi$ drawn on it, with the numbers you'd labelled it with replaced by letters (as shown above).
Oh no - that's not good news.
You look at the back of the paper and find a message that reads:
"Har har... want to get your pumkpin $\pi$ back? Not until you tell me the numbers labelled on your $\pi$."
Bummer! Having a terrible memory, you have absolutely no idea how you labelled your $\pi$.
You continue reading the message:
"Don't worry! Just in case you forgot, I left a liiiiiiitle bit of a clue on 6 separate pieces of paper. But mind you... I'm not always honest..."
Surprisingly, you find 6 pieces of paper under your table:
"1---- is adjacent to 4; is adjacent to 3"
"2---- is adjacent to 4; is opposite 6"
"3---- is opposite 4; is adjacent to 5"
"4---- is adjacent to 6; is not adjacent to 5"
"5---- is adjacent to 3; is not adjacent to 6"
"6---- is not opposite 3; is not adjacent to 1"
Each piece of paper contains 2 pieces of information about how your numbers are labelled. You also know that on every paper, one piece of information is true while the other is false.
Can you deduce the numbers labelled on your pumpkin $\pi$?
(Note: Please don't answer YES.)
(Note 2: If 2 slices are next to each other, then they are adjacent. e.g. A and B. If 2 slices have 2 other slices between them, then they are opposite to each other. e.g. A and D.)
| VQAonline_00054876.png | From (5) we know that 5 is either adjacent to 3 and 6, or adjacent to neither of them. Assume it is adjacent to both:
3 5 6 _ _ _
From (6), since 6 is not opposite of 3, it must be adjacent to 1:
3 5 6 1 _ _
From (1), since 1 is not adjacent to 3, it must be adjacent to 4, and then the last remaining spot must be filled by 2:
3 5 6 1 4 2
But this makes both of the claims in (2) true, which is a contradiction. So our original assumption is false, and we conclude that 5 is not adjacent to 3 or 6. From (3), this means that 3 is opposite of 4, and the only way that works is if 4 is adjacent to 5:
5 4 _ _ 3 _
From (4) we know that 4 is adjacent to 6:
5 4 6 _ 3 _
From (6) we know that 6 is adjacent to 1, and the last remaining spot is filled by 2:
5 4 6 1 3 2
This satisfies all the conditions of the problem.
| https://puzzling.stackexchange.com/questions/31145 |
quant | Computing T-Bill Yield across leap year boundary | Consider this T-Bill (912796TE9) that was purchased on 2019-10-30 and matures on 2020-02-06:
I'm trying to work through some of the basics of the yield calculation.
The days until maturity is 99. (2020-02-06 minus 2019-10-30). That's easy enough.
The price is 99.563575. That's equal to 100 - ((discount) * (99/360)). Again, pretty straightforward.
Where I'm running into trouble is the yield. According to this page we should compute:
yield = ((100-price)/price) * (365/daysLeft)
By my calculations, that generates a yield of around 1.616095%. But as you can see from the screenshot, the actual yield is 1.620522%. So I'm off.
Now it turns out, if I plug 366 into the equation instead of 365, I get the correct result. Why is that? Presumably it has something to do with 2020 being a leap year. But a good fraction of the holding period takes place in 2019 which is not a leap year. What's the rule on this? If any fraction of the holding period until maturity touches a leap year then 366 shall be used?
| VQAonline_00056973.png | Due to the leap year 366 days need to be used here to match UST conventions (which is ACT/ACT). In this case it doesn't matter whether your interest period extends to only 1 day after the 29th of February or, e.g., 200. In fact if you look at the daycount description of the bill it says:
"the day count basis for price and yield calculations is 365 depending on the number of actual days in year counting forward from the Original Issue Date. The basis will usually be 365 but if the year following the issue date includes February 29th then it's 366".
| https://quant.stackexchange.com/questions/49469 |
quant | EUR/CHF fx rate drop on the 15th of January 2015 | I was playing around with some fx rates and what caught my attention was the sudden drop of the fx rate EUR/CHF at the 15th of January 2015 4:00 - 5:00 am EST. What really happened that day? Was there any prior information directed towards traders and market makers in the context of qualitative risk management to avoid heavy looses?
Is there any paper that describes the situation and how biased the volatility forecasts can be from the outliers pollution ?
| VQAonline_00056882.png | What happened was totally unexpected end of peg against the euro @ 1.2CHF regime that Swiss central bank aborted. See some articles about it. As far as I know nobody in the markets knew, there was no indication whatsoever..
In terms of management, I'm afraid lots of people got heavy losses, particularly banks (Austria, Poland, Hungary) - lots of Swiss loans that got shockingly higher instalments overnight (by 20%) caused serious stress to portfolios of banks.
See for instance this good article. or google around this, to get more info - you can set google to look for content only at the beginning of 2015.
Regarding academia, there does not seem to be anything particularly interesting:
https://scholar.google.com/scholar?as_ylo=2015&q=swiss+franc+unpegging&hl=cs&as_sdt=0,5
Regarding volatility forecasting, this would depend on your model, so hard to give a specific answer to that..
| https://quant.stackexchange.com/questions/29694 |
quant | Linear combination of Payoffs using Black-Scholes | Write the payoffs in Figure 3.8 as linear combination of call options and derive a closed form formula for the Black-Scholes price, the Delta, and the Gamma of them. All the Greeks of the option are also linear combination of these call option Greeks. For instance, $$\Delta(t,S) = \Phi(d_1(\tau,K_1,S)) - \Phi(d_1(\tau,K_2,S)) - \Phi(d_1(\tau,K_3,S)) + \Phi(d_1(\tau,K_4,S))$$
Partial Solution: For the strangle we have a pay off of $$(K - S_T)_{+} + (S_T - K)_{+}$$ Therefore the closed form solution of B-S price of option is $$V(\tau,S) = P(\tau,K,S) + C(\tau,K,S)$$ and the delta of the position is $$\Delta(\tau,S) = -\Phi(-d_1(\tau,K,S)) + \Phi(d_1(\tau,K,S))$$ Finally our gamma for this position is $$\Gamma(\tau,S) = \frac{\Phi'(d_1(\tau,K,S)) + \Phi'(d_1(\tau,K,S))}{S\sigma \sqrt{\tau}}$$
I guess my professor made a mistake in regards to the B-S closed form price: for the strange it is $$V(\tau,S) = (-S_0\Phi(-d_1) + e^{-rT}K\Phi(-d_2)) + (S_0\Phi(d_1) - e^{-rT}K\Phi(d_2))$$ and similar for the straddle
where $\tau = T - t$ not sure why we use $\tau$ any explanation of that would be great.
| VQAonline_00056855.png | To express such payoff in mathematical form, it is better to use indicator functions. I assume that the bottom of graphs (i.e., the vertex for the left one and the bottom segment for the right side one) represents zero.
For the left-hand one, the payoff is given by
\begin{align*}
(K-S_T)\pmb{1}_{S_T \le K} + (S_T-K)\pmb{1}_{S_T \ge K} = (K-S_T)^+ + (S_T-K)^+,
\end{align*}
that is, a straddle that involves both a European call and put with the same strike price and maturity date.
For the right-hand one, the payoff is given by
\begin{align*}
(K_1-S_T)\pmb{1}_{S_T \le K_1} + (S_T-K_2)\pmb{1}_{S_T \ge K_2} = (K_1-S_T)^+ + (S_T-K_2)^+,\tag{1}
\end{align*}
that is, a strangle that involves both a European call and put with the same maturity date, but different strikes.
For valuation, as an example, let's consider (1). According to the Black-Scholes' formula, the value of Payoff (1) is given by
\begin{align*}
V=\Big[K_1 e^{-rT} \Phi(-d_2^1) - S_0 \Phi(-d_1^1)\Big] + \Big[S_0 \Phi(d_1^2) - K_2 e^{-rT} \Phi(d_2^2)\Big],
\end{align*}
where the first term is the value of the put option payoff $(K_1-S_T)^+$ and the second is the value of the call option payoff $(S_T-K_2)^+$. Here,
\begin{align*}
d_1^1 &= \frac{\ln \frac{S_0}{K_1} + (r+\frac{1}{2}\sigma^2)T}{\sigma \sqrt{T}},\\
d_2^1 &= d_1^1 - \sigma \sqrt{T},\\
d_1^2 &= \frac{\ln \frac{S_0}{K_2} + (r+\frac{1}{2}\sigma^2)T}{\sigma \sqrt{T}},\\
d_2^2 &= d_1^2 - \sigma \sqrt{T}.\\
\end{align*}
The delta hedge ratio is the sum of deltas of the first put option and the second call options, that is,
\begin{align*}
\frac{\partial V}{\partial S_0} &= -\Phi(-d_1^1) + \Phi(d_1^2)\\
&=\Phi(d_1^1) + \Phi(d_1^2) - 1,
\end{align*}
and the gamma hedge ratio is the sum of gammas of the first put option and the second call options, that is,
\begin{align*}
\frac{\partial^2 V}{\partial S_0^2} &= \frac{\Phi'(d_1^1)}{S_0\sigma \sqrt{T}}+ \frac{\Phi'(d_1^2)}{S_0\sigma \sqrt{T}}\\
&=\frac{\Phi'(d_1^1) + \Phi'(d_1^2)}{S_0\sigma \sqrt{T}}.
\end{align*}
| https://quant.stackexchange.com/questions/24927 |
quant | Struggling with tau in Black-Litterman | According to the omega formula in B-L tau is used in the Omega estimation to determine the degree of uncertainty given to views of the investor:
So, if tau is given a low value then the inverse of omega will be large and therefore suppose a lot of uncertainty in the investors view and so giving more importance to implicit returns in contrast to investors.
In short, and based on this assumption (don't hesitate in correct it) tau can be used to calibrate the importance I give to investors views in opposition to implicit returns and vice versa.
Supposing the above statement is correct, according to
Thomas M. Idzorek paper on B-L model
regarding page 15 he comments that
"When the covariance matrix
of the error term (
Ω
) is calculated using this method,
the actual value
of the scalar (
τ
) becomes irrelevant because only the ratio
τ
ω
/
enters
the model. For example, changing the assumed value of the scalar (
τ
) from 0.025 to 15
dramatically changes the value
of the diagonal elements of
Ω
, but the new Combined
Return Vector (
]
[
R
E
) is unaffected. "
I have made some calculations assigning tau a 0.025 and a 1 and the new Combined Return Vector is unaffected
Then I understand that there is no way I can assign investors views a degree of uncertainty because it does not matter the value I assign to tau, that the return vector will be the same.
Therefore, my questions are:
Are my statements above correct?
If so , whats the point of the existence of tau?
Are there alternative methods to determine investors uncertainty / weights given to implicit or investor returns ?
Thank you in advance for taking your time reading my post.
| VQAonline_00056937.png | Your statement about the properties of $\tau$ is correct. $\tau$ is a measure of uncertainty. I think the problem you are having is because in most practical situations nobody really knows what values should be used for $\tau$ and/or $\Omega$.
There is plenty of practical advice out there, and some of it is very confusing! For example, Jay Walters has written an entire paper on $\tau$ (see https://papers.ssrn.com/sol3/papers.cfm?abstract_id=1701467). That paper discusses the origin of $\tau$ as a measure of an investors uncertainty in their prior returns. Unfortunately, this does not translate into practical advice and it refers to different papers giving different values for $\tau$ (0.05 in one paper and 1.0 in another).
Nobody really knows what $\Omega$ should be either because that would require them to have an estimate of the uncertainty of the views. Most human-generated forecasts don’t come with an associated covariance matrix. Hence, most people use an $\Omega$ that is derived from their estimate of the variance matrix. So, for example, Idzorek’s formula for $\Omega$ assumes that the forecasts are independent when they are not likely to be in practice.
Idzorek’s formula has rolled $\tau$ in to the estimate of $\Omega$. That inclusion means that the effect of $\tau$ is cancelled out in the Combined Return Vector. Hence, as you have noticed, you cannot use $\tau$ as a single scalar to alter the weight of the prior in the final Combined Return Vector if you use Idzorek’s formula. Including $\tau$ has the advantage of giving one single result, but that is not necessarily what you need.
A simple modification to Idzorek’s formula would be to set $\Omega = diag(P\Sigma P’)$. The Combined Return Vector would then change as $\tau$ changes.
Another popular choice for $\Omega$ is given in chapter 9 of Meucci’s Risk And Asset Allocation (and also discussed at Black-Litterman, how to choose the uncertainty in the views $\Omega$ for smooth transitions form prior to posterior). Meucci suggests that people use:
$\Omega = (\frac{1}{c} -1) P\Sigma P’$
| https://quant.stackexchange.com/questions/40820 |
quant | conditional expectation formula of default in CVA | Here is the formula of CVA in page 74 in book Modern Derivatives Pricing and Credit Exposure Analysis.
Here $t_0 = t<t_1<\cdots<t_n = T;$ $\tau$ is the default; $X(t)$ is any value.
I don't much understand how we get the second equation:
$$E^Q[\mathbb{1}_{\tau>t_i}X(t_{i-1})|\mathcal{F}_t] = E^Q\Big[E^Q[\mathbb{1}_{\tau>t_i}]X(t_{i-1})|\mathcal{F}_t\Big]$$
It hints that
This is possible for the expectations containing $X(t_i)$ and $X(t_{i−1})$ since these are both $\mathcal{F}(t_i)$-measurable; apply the tower law of conditional expectations.
Does that mean
$$E^Q[\mathbb{1}_{\tau>t_i}X(t_{i-1})|\mathcal{F}_t] = E^Q\Big[E^Q[\mathbb{1}_{\tau>t_i}X(t_{i-1})|\mathcal{F}_{t_{i-1}}]|\mathcal{F}_t\Big]=E^Q\Big[E^Q[\mathbb{1}_{\tau>t_i}|\mathcal{F}_{t_{i-1}}]X(t_{i-1})|\mathcal{F}_t\Big].$$
But how to convert $E^Q[\mathbb{1}_{\tau>t_i}|\mathcal{F}_{t_{i-1}}]$ to $E^Q[\mathbb{1}_{\tau>t_i}]?$
| VQAonline_00057044.png | Note that, for any $u > 0$,
\begin{align*}
E^Q(1_{\tau > u} \mid \mathscr{F}_u) = e^{-\int_0^u \lambda(s)ds}.
\end{align*}
For example, given $\lambda$, we can define the default time $\tau$ as
\begin{align*}
\tau = \inf\left\{t \in \mathbb{R}_+: e^{-\int_0^t \lambda_s ds} \le \xi \right\},
\end{align*}
where $\xi$ is independent of $\mathscr{F}_{\infty}$ and is uniformly distributed over $(0, 1)$.
Then
\begin{align*}
E^Q\left(1_{\tau>t_i} X(t_{i-1}) \mid \mathscr{F}_t \right) &= E^Q\left(X(t_{i-1})E^Q(1_{\tau>t_i} \mid \mathscr{F}_{t_i}\big) \mid \mathscr{F}_t \right)\\
&=E^Q\left(X(t_{i-1}) e^{-\int_0^{t_i} \lambda(s)ds} \mid \mathscr{F}_t \right).
\end{align*}
Similarly,
\begin{align*}
E^Q\left(1_{\tau>t_i} X(t_i) \mid \mathscr{F}_t \right) &= E^Q\left(X(t_i)E^Q(1_{\tau>t_i} \mid \mathscr{F}_{t_i}\big) \mid \mathscr{F}_t \right)\\
&=E^Q\left(X(t_i) e^{-\int_0^{t_i} \lambda(s)ds} \mid \mathscr{F}_t \right).
\end{align*}
| https://quant.stackexchange.com/questions/68425 |
quant | Why is there a stong intraday-correlation between spot and vol? |
Fig.1 shows an intraday scatterplot of the DAX future against its volatility index VDAX on 6-Jan-2016.
The data suggest a strong negative correlation between the two.
There are various models available that "describe" this effect: For example stochastic vol-models such as the Heston model. However these models only describe but do not explain the effect.
Since prices are the result of trading and market-making, a plausible explanation could be that market participants are buying put-option when the market goes down in order to protect their (long) position thereby driving the vol up; and re-selling them when the market goes up (driving the vol down).
However it is easy to convince oneself that the correlation persists at time-scales that correspond to vol moves that make it difficult to trade out of the bid-offer spread of the option (at the ODAX-exchange). If it was only to reduce the downside risk (in a down move) it would be much cheaper to reduce ones long-position temporarily instead. Clearly options exhibit "gamma", but (as mentioned above) the cost of gamma seems too high given the bid-offer spread of the options.
So I do not really understand which market factors cause this intraday phenomenon of negative correlation between vol and spot moves.
Can anyone suggest an answer?
| VQAonline_00056843.png | This effect is coming from the supply and demand in the options markets. Many portfolio managers want (or need) to buy out of the money put options, and many are willing to sell out of the money call options (thereby funding the purchase of put options). Now, when the market goes down, dealers find themselves short vol and they need to buy options to cover (hence vol goes up). Likewise, when the market goes up, dealers find themselves long vol and they need to sell (thus vol goes down). That's the effect you observe. The timeframe for this effect is almost continuous - many dealers recalculate their positions multiple times intraday.
Yes, there is a skew whereby out of the money puts are more expensive than ATMs and out of the money calls are cheaper. You can think of this as compensation for the expected hedging loss if you are using a simple Black Scholes model. However, many dealers would use a model that anticipates the vol change for the given market move. This model would price the puts and calls closer to the market skew. It would also reduce the losses from flattening the vol position after a market move. As for the question about bid-offers, it is an issue, but in practice a dealer won't just lift and hit in the market. They will rather work to buy and sell close to mid market, which they can probably do using their network of clients.
| https://quant.stackexchange.com/questions/22614 |
quant | Relationship between hike in interest rate and drop in treasuries yields | How does a hike in interest rate results in drop in yields of treasuries?
My understanding was that when interest rate rises, investors would sell-off bonds, which would result in increase in yields.
| VQAonline_00056898.png | What happened was that the Fed indeed hiked by 25bp (as expected) but also conveyed the message that future hikes would be quite gradual (this was not expected). The market therefore altered its expected path of Fed funds downwards and hence the yield of Treasuties downwards. It's all about what happened versus previous expectations.
| https://quant.stackexchange.com/questions/33052 |
rpg | Do Arcane Caster Levels Count as Cleric Levels for Turning/Rebuking Checks? | If I am a Wizard, with no levels of Cleric, and I gain a domain power (through a prestige class1) that Turns X-Creatures as a Cleric Turns Undead; does my arcane caster level equal Cleric levels for that purpose?
Example (Arachnomancer)
1st Level: Poison Save Bonus, Handle Spiders, Spider Domain
Spider Domain: Rebuke or command spiders as an evil cleric rebukes or commands undead. You can use this abilities a number of times per day equal to 3 + your Cha modifier.
Cleric level seems important due to the following table:
If I have no "cleric level" is the Rebuke or Command Spiders essentially doomed as ineffective?
1Earthshaker (Dragon Magazine) gets Earth Domain, which grants Rebuking/Commanding Earth Creatures.
| VQAonline_00057134.png |
The prestige class arachnomancer (Drow of the Underdark 65-8) says
You gain access to the Spider domain and the granted power associated with the domain (rebuke spiders as an evil cleric rebukes undead, a number of times per day equal to 3 + your Cha modifier). (65)
Hence a level 1 arachnomancer rebukes spiders like a level 1 cleric rebukes undead—no matter what other abilities the arachnomancer possesses—, and that's terrible.
The prestige class earthshaker (Dragon #314 57-9) says that the creature
gains the Earth domain's granted power, substituting his earthshaker levels for cleric levels. (58)
And, yes, that's also terrible, but it's worse because while expected entry into the prestige class arachnomancer is at about character level 5, expected entry into the prestige class earthshaker is at about character level 9. Your granted power isn't just bringing almost nothing to the table, it's actually insulting.
Extra domains in general
Although earthshaker predates Complete Divine, that version of the arachnomancer was released long after Complete Divine.1 Both, however, seem to follow similarly the Complete Divine's vague rules on Extra Domains which, in part, says
If a noncleric enters a prestige class that allows access to a domain, the character still gains access to the domain. She can use the granted power bestowed by the domain normally. (20)
Complete Divine, of course, doesn't actually say what normally means here, but, apparently, based on the anecdotal evidence from the above two classes, the game takes normally to mean here that the creature treats its levels in the prestige class as cleric levels, combining with nothing unless the text indicates otherwise. Which, let me say again, is terrible.
Negotiate with the DM
I suggest asking the DM to allow the arachnomancer to rebuke spiders like an evil cleric of twice the creature's arachnomancer level. While that's still terrible, it does sort incentivize staying in arachnomancer, because it (ahem) bugs some DMs when players have a bunch of a different classes on their character sheets. Creatures likely enter earthshaker too late for this quick-and-dirty fix to do any good, and thrice (maximum 20th) earthshaker level might be overreaching, but it couldn't hurt to ask.
1 The original arachnomancer was, confusingly enough, introduced in Underdark, an early but still 3.5 product.
| https://rpg.stackexchange.com/questions/73968 |
rpg | What is the correct term for the die with multiples of ten written on it? | What is the correct term for this die? It is a standard die in any 7 dice set.
It has multiples of ten from 10 to 00 written on it (10, 20, 30, 40, 50, 60, 70, 80, 90, (1)00).
I seem to think that it is called a 'percentile die', is this correct?
| VQAonline_00057136.png | The two ten-sided dice used together to generate a number in the range 1-100 (or 0-99) are percentile dice (plural). The same term is applies to a pair of twenty-sided dice, each marked 0-9 twice, used for the same purpose.
Back in the Before Time, dice sets didn't include a die marked with double-digits; you would just roll different-colored dice, having declared one of them the "tens". I think that sometimes the specific die you are asking about is called the tens die; Chessex calls it a "Tens 10" on their website.
| https://rpg.stackexchange.com/questions/75705 |
rpg | Who is pictured on the cover of Dragonlance Adventures? | Who are the characters depicted on the cover of the Dragonlance Adventures hardcover?
The painting was done by Jeff Easley, and I'm pretty sure it's depicting Tanis taking the crown from Emperor Ariakas. But who is the undead guy in the back? I think it might be Lord Soth, but I don't think I've ever seen him depicted without his trademark bucket helmet.
| VQAonline_00057200.png | You correctly identified the characters depicted in the image: indeed they are
Lord Ariakas (the dying man): the commander of the Dragon Army
Tanis Half-Elven (the standing one with a sword and a crown): one of the protagonists of Dragonlance Saga
Lord Soth (the undead): a Death Knight, whose is an ally of Kitiara, one of the Dragon Highlords
This drawing refers to the moment where Tanis went to pledge allegiance to Ariakan, but instead of putting his sword at the Lord Commander's feet the half elf struck a fatal blow (with the aid of Raistlin Majere). The Crown of Power felt off from Ariakan's head, and since "Whoever holds the Crown, rules!" Tanis went to catch the crown. As soon as Kitiara had understood what was going on, she ordered Lord Soth to catch the crown for herself:
There was uneasy silence in the Hall of Audience as Ariakas’s body tumbled to the floor. The Crown of Power fell from his head with a clatter and lay within a tangle of blood and thick, black hair.
Who would claim it?
There was a piercing scream. Kitiara called out a name, called to someone.
Tanis could not understand. He didn’t care anyway. He stretched out his hand for the Crown.
Suddenly a figure in black armor materialized before him.
Lord Soth!
The above quotes are taken from Dragons of Spring Dawning, Book 3, Chapter 9, Horns of Doom.
| https://rpg.stackexchange.com/questions/140411 |
rpg | Can characters escape from Death House through this method? | I will be DMing the Death House adventure very soon. Because I have players that tend to exploit every little loophole, I am wondering the following:
Once the party refused to sacrifice someone and have to escape, would there be an easy escape route by climbing up through the trap door opening in the basement, then going through the wall near the exit and then getting out through the front gate?
To illustrate what I mean, here is a map with the escape route I'm thinking of:
As written, once you re-enter the house, all doors will become scythes and all windows will become bricks and inner walls will become brittle and turn into rat swarms. But, there is nothing written about the front gate and whether the wall next to it, is considered an outer wall.
In someone's notes, I read that the only valid escape would be
from the balcony.
Is that really true?
I mean, of course it would be up to me to decide and most likely it would be too easy to just shortcut in the first floor, but I think it still could be argued nonetheless and I want to be sure I didn't overlook anything.
| VQAonline_00057214.png | That's a valid route.
But it's still not easy. You've got to get from location 38 to location 32 in the basement (assuming you even know location 32 exists). Once you're there it's clear from the text that the trapdoor is intended to allow movement from the basement into the house proper.
Then when you're up in the house you're in a poisonous-smoke filled room whose walls will burst with rats when you try to hack through them. It's a shortcut, but no cake-walk.
Welcome to Barovia.
| https://rpg.stackexchange.com/questions/149128 |
rpg | Is this attack type chart correct? | I am wondering if this chart showing the types of attacks in 5e-dnd and what things they can count towards is correct:
(source1)
The chart works by listing on the y-axis different ways of making an attack and then along the x-axis it lists different phrases features throughout the books use. If something on the y-axis satisfies that condition on the x-axis their box is green, if not, the box is red. Several have descriptions explaining their content as I felt it might be necessary/helpful. The two Yellow boxes are yellow because the answer is conditional (not simply yes or no).
I have chosen to avoid talking about spells in this chart mostly because they would take up quite a few columns/rows, and also because they do not seem to cause people nearly as much confusion as the other types of attacks.
For the purposes of this I would like three things to be assumed. This is so I can know if the main part of the chart is correct and not the sections that have been put up to debate previously on this Stack:
That using a weapon to make an improvised attack removes all of its properties including melee/ranged. Thus throwing a bow at somebody would not be considered an attack with a ranged weapon, because the bow has lost that property, similarly throwing a mace at somebody would not be considered an attack with a melee weapon.
From the same question as above, that improvised attacks transform whatever is being used to make them into weapons for the purpose of that attack. Thus using a table-leg or shield in an improvised attack would momentarily make each of them count as a weapon.
That you cannot use a weapon for a shove or grapple so they do not qualify as attacks with weapons. (A question where the answer was iffy)
1 - Note that the source may change after this posting as it is a Google Doc. For the sake of this question, use the image I have embedded here.
| VQAonline_00057217.png | Yes
This table appears to be correct, although the presence of rows 8 and 9 are not necessary since the data is covered by the previous rows.
For your third assumption, I would like to clarify that you wouldn't have to drop your weapon to make a shove attack. You could still use the weapon to push someone for example, but it would not qualify as a "weapon attack" at all - e.g. the Great Weapon Master feat would not apply. This is because grapple specifically states that you must have at least one free hand, whereas the shove action says nothing on the matter.
Using at least one free hand, you try to seize the target by making a grapple check instead of an attack roll [...]
| https://rpg.stackexchange.com/questions/149651 |
rpg | Can a flying character can use Ant Haul to carry another character? | One of my player is a level 8 Oracle of Flame and she has the revelation Wings of Fire.
She is not strong enough to lift someone while flying. She would like to. She plays a Peri Aasimar with a strong angelic savior behavior.
As an Oracle, she could learn Ant Haul.
The target’s carrying capacity triples. This does not affect the creature’s actual Strength in any way, merely the amount of material it can carry while benefiting from this spell. It also has no effect on encumbrance due to armor. If the creature wears armor it still takes the normal penalties for doing so regardless of how much weight the spell allows it to carry.
As DM, I plan to allow it. Now, I would like to know if it not a big deal if I consider that the amount of material includes a living being.
| VQAonline_00057212.png | Yes, they can
Ant Haul says that "the target’s carrying capacity triples", meaning that her carrying capacity, assuming that if it's triple is enough to carry all their gear plus the carried creature and their gear too, shouldn't be affected by the fact that she is flying, other than reducing her speed and increasing her armor check penalty.
If three times her carrying capacity is still not enough to put her under Heavy Load, then she cannot freely move while carrying that weight, and should probably fall (GM Fiat) or drag the creature at 5 feet per round (see Lifting and Dragging). If she has 10 Str for instance, her maximum load is 100 lbs (~45Kg), or 300 lbs (~136Kg) under Ant Haul, which should be enough to carry someone else.
| https://rpg.stackexchange.com/questions/148760 |
rpg | Is this d15 verifiably fair? | Following off of a question asking for how to make a d150 in which this d15 was mentioned in an answer, I was wondering if this d15 is fair (gives an equal distribution of results over its range). Is it?
Fifteen-sided d15 die. This design is based on spacing points as equally as possible on a sphere and then cutting planar slices perpendicular to those directions. [...] Note that this design is not isohedral.
| VQAonline_00057207.png | Based on the description, this die is most likely not perfectly fair
The important parts of the description are:
This design is based on spacing points as equally as possible on a sphere and then cutting planar slices perpendicular to those directions. [...] Note that this design is not isohedral.
Isohedral means that all faces of the die are identical. The fact that this d15 is not isohedral means that the different faces have different shapes. Furthermore, the method of construction described in the first sentence will not result in a fair die. Note that the points are spaced "as equally as possible". It is not possible to space 15 points out on a spherical surface exactly equally; this is only possible for 4, 6, 8, 12, and 20, which is why those dice are the only completely symmetrical ones. Hence, when the 15 faces are cut, some of them will be more distant from their neighbors than others, which gives those faces a higher chance of being rolled. In theory, it might be possible to counteract this by varying the sizes of the faces, but this would be a difficult optimization problem since shrinking one face not only reduces the probability of rolling that face, but it also makes the neighboring faces more likely to be rolled and affects the overall center of gravity of the die, which in turn changes the probabilities of every face. Realistically, the only way to get this right would be through empirical testing and iteration. That is, building some dice, testing them, making adjustments, and repeating until the dice is empirically determined to be fair to within detectable limits.
Given the amount of work that would be required to design a fair die, there's no way they would do all the work to to make a fair die and then fail to mention that in the description. From that, we can conclude that the die is almost certainly not fair.
In fact, there are other dice where the process of making them as fair as possible is described in detail, such as the d30. The fact that no such description is provided for the d15 or any of the other non-isohedral dice is further evidence that they are no more fair than the non-uniform arrangement of faces would imply.
How fair do you need it to be?
However, it's probably pretty close to fair. And if the designers are smart, they will have placed the numbers on the die in such a way as to minimize the unfairness by ensuring that the most and least likely faces are spread equally throughout the range of the die instead of clustered together in a small range. Given that, it's likely fair enough for many purposes. For example, if the arrangement of faces has any kind of symmetry to it, they could use that to make the distribution of rolls symmetric, such that the average roll is exactly 8 (i.e. the average of all faces), and that the probability of rolling over 8 is the same as the probability of rolling below 8. But if you need something truly and precisely uniform, this isn't it.
| https://rpg.stackexchange.com/questions/147221 |
rus | "Авторство статей принадлежит ведущим специалистам, каждого в своём вопросе" - можно? |
Уникальное издание, чья дальнейшая судьба пока неизвестна. Первый том
вышел в 2000 году. “С самого начала энциклопедия планировалась как
издание, далеко выходящее за рамки православного мира: в нём должны
были быть представлены основные сведения по всем христианским
конфессиям и иным вероисповеданиям, значительные материалы из области
философии, морали, этики, искусства, музыки”. Авторство статей
принадлежит ведущим специалистам, каждого в своём вопросе. В работе
по созданию энциклопедии участвуют: Московская духовная академия,
институты Российской академии наук, Московский, Санкт-Петербургский и
ряд других крупнейших региональных университетов, синодальные комиссии
и отделы Московской Патриархии, РАН, а также научные центры США,
Греции и Италии. В настоящее время выпущено 40 томов (с учётом
неалфавитного тома — 41-го). В частности: "Православная энциклопедия. Том
XXVIII". Всё об искусстве Италии. Коротко и с последними датировками.
Пожалуйста, увидите ошибки - свистните!
| VQAonline_00057329.png | Авторство статей принадлежит ведущим специалистам, (специализация) каждого в своей области.
Или: Авторство статей принадлежит ведущим специалистам — каждого в своей области.
Тире чётко обозначает присоединение, но не смотрится в этом тексте. В то же время читать предложение (при постановке запятой или тире) надо с подчеркнутой паузой.
Пояснение
1) Обособленный оборот похож на присоединительную конструкцию, тогда согласование в падеже не требуется. А при согласовании теряется смысл, тогда оборот действительно лучше убрать. Оставить — "ведущим специалистам в соответствующих вопросах/областях".
2) Сочетание "специалист в своем вопросе" как-то мало употребляется, обычно — в своей области, в своем деле, в области чего-то.
| https://rus.stackexchange.com/questions/436519 |
rus | Каждый месяц Facebook использует (или "используют") 1,8 миллиарда человек | В одном фейсбучном сообществе людей позабавило такое сообщение:
Можно представить, что это платформа Facebook использует людей, а не они используют платформу Facebook.
Я заглянул на сайт gramota.ru:
Согласование сказуемого со словами «тысяча, миллион, миллиард»
Сказуемое при словах тысяча, миллион, миллиард обычно принимает форму подлежащего (единственное число, женский или мужской род). Тысяча человек каждый год отдыхает в этом санатории. Миллион тюльпанов посажен на клумбе.
Но, с другой стороны:
Согласование по смыслу предпочтительно:
3) если нужно подчеркнуть раздельность действий каждого действующего лица, называемого подлежащим, а также подчеркнуть активность действующих лиц: Ряд сотрудников нашей организации выступили с инициативой; ср.: В прошлом году было построено множество дорог.
Насколько я понял, "использует" не является ошибкой, но всё-таки предпочтительнее писать "используют"?
| VQAonline_00057320.png | Как уже было сказано, написанное не является ошибкой. Боюсь, нет объективного ответа на вопрос, что предпочтительно в данном случае.
Аргументы в пользу единственного числа: желание обратить внимание на количество, а не на активность действующих лиц, наличие слова "более" (обозначение приблизительного количества). В пользу множественного числа - только устранение двусмысленности (кто кого использует), но, на мой взгляд, этот аргумент важнее остальных.
А еще замечу, что двусмысленность можно устранить, употребив прямой порядок слов: "Каждый месяц более 1.8 миллиарда человек использует Facebook". И волки сыты, и овцы целы.
Дополнение
А вообще-то Фейсбук не используют, им пользуются. Так что рекламу эту нужно менять.
| https://rus.stackexchange.com/questions/431813 |
rus | Как склоняется и какого рода слово "нод(а)"? | Нода - это заимствование от слова node (узел). Из викисловаря, узнал, что это слово женского рода (вроде как). Используется в компьютерных приложениях для обозначения блока программы, который соединяется с другими нодами и образует сложную структуру:
Также используется для обозначения компьютера в специфических сетях
Кое-что очевидно и используется повсеместно:
Нодовый редактор
Ноды
Группа нодов
Кое-что неочевидно, и примеров использования не найти. Например, каким образом склонять это слово, особенно во фразах:
Использовать активную нод(у)
Выделенных нод(ов)
Цвет ноды(?)
Добавить к ноде(у)
Точно ли это слово женского рода?
Есть варианты использования как мужского рода:
Исправляем это недоразумение используя нод Hue/Saturation/Value.
https://pikabu.ru/story/vozmozhnosti_sovremennoy_kompyuternoy_grafiki_4291152
так и женского:
Нода Copy. Наследование трансформаций и атрибутов. Техника Copy
Stamping.
http://vfxlaboratory.ru/kurs/houdini-artist-101
| VQAonline_00057339.png | В сфере IT работаю уже почти 30 лет. По рабочим вопросам общаюсь с огромным количеством коллег и всегда слово "нода" было женского рода. Иногда доводилось слышать применение этого слова в мужском роде от начинающих IT-шников, но обычно старшие товарищи рано или поздно объясняли им, как должно быть правильно, и они исправлялись ;)
И кстати, это не единственный парадокс, доставшийся нам со времен ФИДО. Два наиболее значимых термина там имеют совершенно нелогичный род. Кроме ноды, которая в оригинале "node" (узел), и поэтому, по идее, должна была бы быть мужского рода, есть еще поинт, который имеет мужской род, хотя в оригинале он point ("точка"), и должен был бы иметь женский род.
Что же касается примеров неправильного применения рода этих слов на некоторых ресурсах - то тут, по-видимому, виновато слишком быстрое расширение круга энтузиастов, которые не сразу успевают ознакомиться с традиционной терминологией. Но они тоже исправятся, поверьте :)
| https://rus.stackexchange.com/questions/447681 |
rus | Словари не хотят водных часов, только водяные, - как быть? |
У меня:
В садах на вилле Боргезе есть водные часы, чуть ли не барочные.
Надо повнимательнее почитать про их устройство.
| VQAonline_00057351.png | Общепринятое название — водяные часы, что соответствует одному из значений суффикса ЯН в словаре Ефремовой: работающий на том, что названо мотивирующим словом (ветряной, водяной, торфяной).
Иногда встречается название водные часы, например: Маленький гений / Научный набор. Водные часы. https://www.wildberries.ru/catalog/3108786/detail.aspx
Но в этом случае вода не является непосредственно рабочей жидкостью: на воде работают батарейки, а часы получаются электрические. Здесь используется суффикс относительного прилагательного Н с общим значением.
Поэтому водные часы — это скорее авторское название (возможно, допускается как упрощенный вариант).
| https://rus.stackexchange.com/questions/450608 |
rus | Ключи от обеих ворот? | На Авито продают гараж с таким описанием:
Есть ключи от обеих ворот или от обоих ворот? Или следует писать так: имеются ключи от обеих створок ворот?
| VQAonline_00057338.png |
Есть ключи от обеих ворот или от обоих ворот?
Оба варианта ненормативны.
Или следует писать так: имеются ключи от обеих створок ворот?
Да, в случае, если речь идет именно о "створках". Но вообще-то у ворот не створки, а створы. Поэтому лучше будет "Имеются ключи от обоих створов ворот".
Другой вопрос, если мы имеем двое ворот.
Вроде бы, коль скоро ворот двое, то и обоих (обе формы - м. р.). Но вот тут возникают сложности.
Во-первых, сама такая форма "двое ворот" несвободна, хотя в современном языке признается почти всеми.
В некоторых случаях для обозначения количества используются, наряду с
количественными числительными, также числительные собирательные (двое,
трое, четверо, пятеро, шестеро, семеро, восьмеро, девятеро). Двумя
последними числительными мы практически не пользуемся. Собирательные
числительные используются используются ограниченно, а именно:
...
б) с существительными, имеющими формы только множественного числа: двое ножниц,
трое суток;
http://gramma.ru/RUS/?id=2.13
А во-вторых, в отличие от "двое" форма "оба"/"обе" в именительном падеже совершено не вяжется с множественным числом даже в просторечии.
При употреблении собирательного числительного оба - обе в сочетаниях с
существительными женского рода в косвенных падежах используются формы
обеих, обеими, обеим и т. д. Эти числительные не употребляются с
существительными, не имеющими формы единственного числа, так как у них
отсутствует категория рода. Нельзя сказать у обоих ворот (нет формы
именительного падежа: оба - обе ворота), можно: у тех и у других
ворот.
(там же, курсив мой - b-s)
Видимо, и косвенные падежи ("обоих"/"обеих") тут неприменимы, хотя они и меньше режут слух, чем именительный.
Так что фразу в любом случае надо править.
Или "от обоих створов" или "от тех и (от) других ворот".
| https://rus.stackexchange.com/questions/444752 |
rus | Кресло или стул? |
Что это, компьютерный стул или компьютерное кресло? Отчего сходные по форме предметы мебели могут обозначаться различно? Проведите, пожалуйста, границу между понятиями "Кресло" и "Стул". На каком существенном основании мы имеем право их разделять?
| VQAonline_00057354.png | В настоящее время выпускается большое количество предметов мебели для сидения. К ним относятся стулья, кресла, полукресла.
Основной признак для различения — высота сиденья.
Функция стула — придать телу человека удобное положение за обеденным или рабочим столом, поэтому сиденье находится на расстоянии 45—50 см от поверхности пола.
В случае кресла этот параметр ниже и составляет 40—42 см.
Стул имеет неглубокое (50—55 см) и узкое (43 см) сиденье, спинка обычно зафиксирована в одном положении. Ее высота находится в пределах от 40 до 45 см.
Но существуют модели для работы, которые предоставляют возможность регулировать угол наклона спинки, высоту, а также ширину и глубину сиденья — это позволяет создать комфортные условия. Такой вид мебели называют офисными креслами, но по своей сути они все равно считаются стульями, несмотря на различные функции и дополнительные конструкционные элементы (подлокотники, подголовник, подколенники).
Кресло обладает большими размерами. Глубина изделия, предназначенного для отдыха, составляет от 45 до 60 см, а ширина от 48 до 60 см.
В стационарных моделях наклон спинки находится в интервале от 110 до 125°. Существуют конструкции, позволяющие регулировать это значение, что дает возможность принять расслабляющую позу.
Многие считают, что разница между стулом и креслом заключается в наличии подлокотников. Дизайнеры называют стул с подлокотниками полукреслом, хотя суть предмета от этого не меняется. Есть модели кресел, в которых подлокотников вообще нет.
Жесткость — не показатель. Современные кресла выполняются из натурального дерева, металла, стекла, пластика и могут не иметь мягкой обивки. Для создания необходимого комфорта их дополняют подушками или съемными покрытиями.
Итак, если предмет мебели дает возможность удобно расположиться за столом во время работы или приема пищи, то это привычный стул. (Подлокотники и мягкость сиденья не являются определяющими характеристиками.) А вот кресло дает возможность расслабиться после трудового дня, занять самую удобную позу и совершенно не располагает к трудовым подвигам.
Чем отличается стул от кресла?
| https://rus.stackexchange.com/questions/452785 |
rus | Матушка-земля (-природа, -Россия, -Волга), но матушка государыня (игуменья, настоятельница, царица), - почему? | Почему "матушка" то с дефисом, то без? Есть ли правило?
Словарь себе противоречит (см. матушка-Русь - матушка Россия):
| VQAonline_00057357.png | Слово матушка может использоваться как обращение и как приложение. Также это слово может относиться к нарицательному и собственному имени. Все эти варианты надо различать.
По общим правилам Розенталя обращение пишется раздельно (сравнить: товарищ, гражданин, госпожа и т.д.).
Написание приложения зависит от позиции для имен собственных: раздельно перед именем собственным и через дефис после него.
Приложения, отнесенные к нарицательному существительному, пишутся через дефис в любой позиции, но раздельное написание как исключение для приложений с качественным (определительным) значением (красавица невеста), в ПАС этого исключения нет.
И что мы тогда имеем:
матушка Россия, матушка Русь, Россия-матушка, Русь-матушка, Волга-матушка;
лень-матушка, матушка-природа, земля-матушка, матушка-земля, деревня-матушка;
матушка царица, матушка игуменья (обращения), у матушки царицы (определительное значение приложения);
Розенталь допускает написание матушка-Русь как устойчивое. http://old-rozental.ru/punctuatio.php?sid=111#pp111
При наличии определения возможно дефисное написание: наша матушка-Россия.
Примеры:
Ох, ты Русь-матушка… И впрямь ― умом тебя понять невозможно. [«Криминальная хроника», 2003.07.24]
Люди были Неясны самим себе. Ах ты, матушка Россия, что ты делаешь со мной? То ли все вокруг смурные? То ли я один смурной? [Василий Аксенов. Таинственная страсть (2007)]
А прирост населения в полтора раза увеличился. Опять отдувается деревня-матушка. Не хотим мы рожать в городе, и всё тут. [Василий Шукшин. Печки-лавочки (1970-1972)]
Он улыбнулся. ― Подождите, война кончится победой, и тогда интернационалисты объявят: " Наша матушка-Россия всему свету голова". [Василий Гроссман. Жизнь и судьба, ч. 1 (1960)]
Сами поверили в свой титанизм. Ты же угодлива, ты и завистлива, матушка Русь. Сложный характер. В такой дихотомии вся ее сласть. [Леонид Зорин. Глас народа (2007-2008) // «Знамя», 2008]
| https://rus.stackexchange.com/questions/455807 |
russian | What is the difference between "Куда ты идёшь?" and "Куда ты собрался?" | I recently learned that
Куда ты собрался?
usually gets translated as
Where are you going?
Or, at least it does on Reverso.
This raised at least a couple of questions for me. The first is the title of this post — What is the difference between
Kуда ты идёшь?
and
Куда ты собрался?
The second thing that piqued my curiosity is the fact that "собрался" is past tense perfective. If one makes the decision to use собраться, why not use a future tense form of it? But, as you can see from the Google Ngram below, "Куда ты соберёшься?" doesn't even make the cut:
I am also curious about the frequency of past tense perfective verbs being translated as present tense verbs in English. Does this happen with great frequency? Are there certain types of verbs that tend to do this? Is "собираться" one of them, and, if so, does this group of verbs have a category with a name? And, finally, is there a particular name for when a verb is past tense in the original language, but present tense in the translated language?
If you want more context, this whole inquiry came about after a learning session in which one of my Russian tutors on iTalki is helping me understand the dialog in this short film:
Ночь
The phrase in question is found just shortly after minute 1:20, and conjugated for a female obviously (собралась vs. собрался).
I didn't realize I had so many questions about this phrase until after the session ended, but that's okay because somebody else might be curious about this, too.
| VQAonline_00057436.png | This depends on context — particularly whether the question is posed while the person addressed is preparing to leave, or in the process of actually leaving.
While preparing to leave (e.g. ironing their clothes):
Kуда ты идёшь? - Appropriate;
Куда ты собрался? - Not appropriate because preparations to leave are not yet concluded;
Куда ты собираешься? (Where are you preparing to go?) - Appropriate, because the question is about an ongoing process;
After preparations are concluded, but before starting off (e.g. the person addressed has put on new clothes, but hasn't walked out the door):
Kуда ты идёшь? - Appropriate;
Куда ты собрался? - Appropriate. It may imply disapproval — particularly if there were no visible preparations.
When someone is in the process of leaving (e.g. on the street):
Kуда ты идёшь? - Appropriate;
Куда ты собрался? - Appropriate; The crux here is that someone's appearance and/or behavior is unusual and suggests some special occasion.
| https://russian.stackexchange.com/questions/25003 |
russian | Meaning of the word сафир(ъ) in this passage? | I want to find out what the word сафиръ means in this passage from an old textbook. I cannot find the word in any dictionary. I think it might mean "ambassador" but am not sure.
| VQAonline_00057387.png | САФИР Мориц Готлиб (Moritz Gottlieb Saphir, 1795-1858) - немецкий юморист и журналист. Впервые обратил на себя внимание сборником стихов «Poetische Erstlinge» (1821). Издавал театральные и юмористические журналы, пользовавшиеся большим успехом. В Берлине издан был против С. памфлет, на к-рый он ответил брошюрой, выдержавшей 4 издания за неделю: «Der getodtete und dennoch lebende Saphir» (Убитый, но тем не менее живой Сафир, 1828). Литературная производительность С. весьма велика. В 1884 было издано собрание его избранных сочинений в 12тт., в 1890 - сочинения в 26тт. Наибольшим успехом пользовались «Fliegendes Album fur Ernst, Scherz, Humor...» (Летучий альбом серьезного, шуток, юмора и жизнерадостности, 1846), «Conversations-Lexikon fur Geistwitz und Humor» Словарь остроумия и юмора, 1851-1852, 2 Aufl., 1860, 3 Aufl., 1893), а также «Humoristische Abende» (Юмористические вечера, 1830), «Dumme Briefe» (Глупые письма, 1834) и др.
| https://russian.stackexchange.com/questions/12179 |
russian | Как называется удлинитель, снабжённый двумя или более розетками? | Как называется удлинитель, снабжённый двумя или более розетками?
| VQAonline_00057388.png | Дополню:
На большей части территории России эту штуку называют "удлинитель".
При этом среди пожилого поколения, а так же в деревнях можно встретить название "переноска", которое можно отнести к местному диалекту.
Так же, пожилые люди часто называют их "тройник" независимо от того, сколько в них розеток.
Если в приборе имеется защита от перепадов напряжения - это "сетевой фильтр".
Однако, большое количество людей называет их "пилот", т.к. на момент появления сетевых фильтров в России самой распространенной фирмой, выпускающей их, была фирма "PILOT", а т.к. особенно старшее поколение не знало правильного названия - просто читали единственное слово, написанное на сетевом фильтре. Название прижилось, но сейчас используется чаще взрослыми людьми.
Подобное (Как с PILOT) так же было с копировальными аппарат фирмы Xerox - это настолько прижилось, что сейчас практически любой русскоговорящий человек назовет любой копировальный аппарат "ксерокс", независимо от фирмы-производителя.
| https://russian.stackexchange.com/questions/12671 |
russian | One Crayz but nice to underestand on KitKat Choclate? | anyone can help me to understand what is the translation of words in a box that I draw a circle on it in the following KitKat Picture into English? (what is the words top of 5% in English)? it's so strange for me to read it because my native is Spanish.
any idea?
| VQAonline_00057396.png | The answer is simple;
на порцию 23,5 г = per portion of 23,5 g / por cada ración de 23,5 g;
ккал = kcal (a unit of energetical value of food).
Trivia: in Ukranian (another East-Slavic language) the words kit-kat could be understood as 'cat the executioner' (gato el verdugo).
| https://russian.stackexchange.com/questions/14310 |
russian | What is "spiral binding machine" called in Russian language? | What is "spiral binding machine" called in Russian language?
*n.b. it is also known as "comb binding machine".
I've been searching googling and I didn't find answer. My purpose is to find the translation in order to find one in Ukrainian web-store which sells it.
| VQAonline_00057405.png | There are 3 options:
Переплетная машина
брошюровщик
переплетчик
| https://russian.stackexchange.com/questions/15133 |
russian | English Conditionals to Russian? | Does anyone want to try to translate this table into Russian?
In English there are 4 conditionals (Type 0, 1, 2, 3, 4).
I have a good idea of how these translate, but I would like to see what the great members on this stack will come up with.
| VQAonline_00057380.png | I'm not a professional linguist, so I can't provide any reference to the textbooks on this matter, but as a native speaker, my translation is below (the cells in the table correspond to the table from the question):
+----+---------------------------------------+----------------------+
| 0 | если я пью кофе вечером | я плохо сплю |
| | если я выпью кофе вечером | я плохо сплю |
| | если я выпиваю кофе вечером | я плохо сплю |
| | если я выпил кофе вечером | я плохо сплю |
+----+---------------------------------------+----------------------+
| 1 | если я выпью кофе сегодня вечером | я буду плохо спать |
+----+---------------------------------------+----------------------+
| 2 | если я бы выпил кофе сегодня вечером | я бы плохо спал |
+----+---------------------------------------+----------------------+
| 3 | если я бы выпил кофе в прошлый вечер | я бы плохо спал |
+----+---------------------------------------+----------------------+
As far as I can see from this table, with imaginary situations one always uses the particle "бы" with a verb in the past.
Also imaginary situations in the future and present differ from ones in the past only by a verb in the if clause, that is only by the tense of a verb in this clause.
| https://russian.stackexchange.com/questions/9506 |
russian | Meaning of "выдавить на мороз"? | I have seen somewhere they use it not in terms you could think you would do with tooth paste.. or in Siberia, related to a physiological process..
No, the example is:
"А конкурентов выдавят на мороз"?
A Russian mafia way of doing business?
http://fritzmorgen.livejournal.com/1065051.html#cutid1
I must admit there is just one place so far where it has been used, so metaphor or a typo?
| VQAonline_00057401.png | Rather than a typo, I would call it a mixed metaphor - squeezing used as a metaphor for applying whatever tactics to reduce your competitors' ability to compete, and the frost part implying that these competitors won't like the situation they'll end up in.
| https://russian.stackexchange.com/questions/14720 |
scicomp | Scaling/Performance of Matlab's svds function (Lanczos bidiagonalization) | I have a simple Matlab script which aims to compute $k$ singular values of a matrix $A$. $A$ is a random dense square matrix of size $5000\times5000$, with 100 of its singular values constrained to be 0 (though that last detail does not seem to matter for my question).
I'm doing this in Matlab via [Uk, Sk, Vk] = svds(A, k);. According to the documentation, svds uses Lanczos bidiagonalization to compute these values. I looked at the function definition (edit svds) and do not see any relevant branching, e.g. using different algorithms under the hood based on different conditions. However, when I increase $k$, I get very curious scaling/performance:
The docs mention
Increasing k can sometimes improve performance, especially when the matrix has repeated singular values.
But I interpret this to mean performance would be improved per $k$, rather than some huge reduction in total overall runtime.
Is this a known behavior of Lanczos bidiagonalization (an algorithm I'm not very familiar with)? Or does anyone have any speculations as to why the performance of svds is like this?
Edit: Here is a minimal version of my script so others can try to reproduce:
results = [];
A = rand(5000, 5000);
[U, S, V] = svd(A);
dS = diag(S);
dS(4900:5000) = 0;
A = U*diag(dS)*V;
b = rand(5000, 1);
for k = 100 : 100 : 4500
tic
[Uk, Sk, Vk] = svds(A,k);
Ahat = Vk*diag(1./diag(Sk))*Uk';
test = Ahat * b;
time_k = toc
results = [results; k time_k];
end
plot(results(:,1), results(:,2))
| VQAonline_00057608.png | I was able to reproduce your initial result via the snippet. However, by adding some more options to your svd call:
[Uk, Sk, Vk] = svds(A,k,'largest','display',true);
we see that the algorithm indeed changes to a dense one (@ThijsSteel).
For 300 singular values:
=== Singular value decomposition A*v = sigma*u, A'*u = sigma*v ===
Computing 300 largest singular values of 5000-by-5000 matrix A.
Parameters:
Maximum number of iterations: 100
Tolerance: 1e-10
Subspace Dimension: 900
Find largest singular values for A*v = sigma*u, A'*u = sigma * v.
--- Start of Lanczos bidiagonalization method ---
Iteration 1: 144 of 300 singular values converged. Smallest non-converged residual 1.4e-09 (tolerance 1.0e-10).
Iteration 2: 300 of 300 singular values converged.
---
To check if singular value multiplicities were missed, restart the method, looking for k+1 singular values.
---
Iteration 3: 301 of 301 singular values converged.
---
No additional multiple singular values found. Successful return.
---
time_k =
55.5512
For 2300 singular values:
=== Singular value decomposition A*v = sigma*u, A'*u = sigma*v ===
Computing 2300 largest singular values of 5000-by-5000 matrix A.
Parameters:
Maximum number of iterations: 100
Tolerance: 1e-10
Subspace Dimension: 6900
Compute SVDS by calling SVD, because the subspace dimension is equal to the minimum matrix size.
time_k =
45.7203
| https://scicomp.stackexchange.com/questions/35670 |
scicomp | How to demonstrate the order of convergence of FTBS method for solving a hyperbolic PDE | consider the Purely hyperbolic model problem
$$u_t+au_x=0$$
$$u(-1,t)=u(1,t) \text{ (periodic boundary)}$$
$$u(x,0)=f(x)$$
with $f(y)=\sin(2\pi y)$. Furthermore the exact solution is given by $u(x,t)=f(x-at)$. I have implemented Forward–time backward–space (see page 1: http://www.etakl.net/notes_etc/numerical/schemes.pdf ) on a uniform grid in time and space and the figure demonstrates my results with certain values of dt, dx and a.
MY QUIESTION: How can I construct a test/example to demonstrate the order of convergence? In theory the order of convergance should be 1 in time and 1 in space, right?
I am using the FDM book by LeVeque and this problem is from chapter 10.
I am using Python and I will be happy to share my code if needed. Thanks
| VQAonline_00057617.png | You could refine your discretization and then compare the logarithm of the error ($\log |e|$) with the logarithm of the size ($\log h$) of your elements. Using a linear regression you could obtain an approximation of the order of convergence. Keep in mind that this order of convergence is asymptotic when $h \rightarrow 0$, so, for "large" $h$ you could see a different behavior.
| https://scicomp.stackexchange.com/questions/37318 |
scicomp | Finding curves where function goes to zero in two dimensions | Suppose $f(x,y)$ is a complex function of two real arguments with roots* that are not discrete points but lie in curves. (Is there are term for this characteristic?) An example is shown below: the black curves show all the points in the $(x, y)$ plane where $f(x, y) = 0$. What is the best way to find these curves numerically, within a rectangular region?
The obvious solution is to consider 1-D slices along the $x$- or $y$-axis, and use standard 1-D root-finding algorithms to find the discrete roots along these slices. These points can then be joined up appropriately to form the curves. However, I wonder if there is a more efficient strategy, taking into account 2-D information.
Answers can assume some of the properties shown in the example plot. The curves do not terminate within the rectangular region, they do not intersect, and they always have a negative gradient.
*Definition of root: a point $(x_r, y_r)$ such that $f(x_r, y_r) = 0$.
| VQAonline_00057584.png | This is a technique called continuation. It typically works by using Newton's method to find one root, then you take steps along the root curve by picking a nearby point as the initial guess for the next Newton step. This is usually done to solve problems of the form $$F_\lambda(x_
\lambda)=0$$ where $\lambda$ is some parameter, but your problem can be recast into this form.
If done correctly, this should get what you need provided that 2 root curves don't intersect each other and the root curves don't suddenly stop. An easy method to code yourself provided you have a good Newton solver is pseudo-arclength continuation that essentially tries to progress along the root curve via an estimation of the arclength along the curve, and enforces this condition by adding an extra equation to the Newton problem. In this formulation, the derivatives can be approximated by a forward difference and the "forward" values of $u$ and $\lambda$ are the unknowns for the new system.
| https://scicomp.stackexchange.com/questions/33290 |
scicomp | Estimation of viscosity from critical properties |
The above graph represents reduced viscosity as a function of reduced temperature for several values of the reduced pressure.
I am writing a code which will estimate the viscosity, in the following steps :
Calculating critical viscosity($\mu_c$) by using the formula,
$$ \mu_c = 7.70M^{0.5}p_c^{2/3}T_c^{-1/6} $$
Calculating reduced temperature and pressure as,
$$
T_r = \frac{T}{T_c} \\
p_r = \frac{p}{p_c} $$
Now, from the graph at the top, estimating $\mu_r$ by using $T_r$ and $p_r$ values calculated from the previous step.
Finally, calculating the predicted value of $\mu$ as,
$$ \mu = \mu_r\mu_c $$
(this value of $\mu$ is unusually a good agreement with the measured value)
Question: How do I feed/extract the data/equation of the plot (top) which is experimentally generated so that I can also plot/test it in my code?
P.S - All other parameters $T_c$ , $p_c$ , $T$ , $p$, $M$ will be input by the user
REFERED : O. A. Uyehara and K. M. Wastson, Nat. Petroleum News, Tech. Section, 36, 764(Oct. 4, 1944); revised | Transport Phenomena, 2nd edition, R. Byron Bird, Warren E. Stewart, Edwin N. Lightfoot
| VQAonline_00057594.png | You can use Plot Digitizer and extract the data points in your image graph as a xml file and then you can parse it by using Python. It's pretty straightforward. You need to import the image of your graph into the software. Then calibrate the X and Y axes by specifying the $x_{min}$, $x_{max}$, $y_{min}$, and $y_{max}$ which are the min and max of X and Y axes. Note that if X or Y axis is in logarithmic scale, you can specify it in the software during calibration. Finally you just manually touch the points in your graph and software would save the X and Y of points for you and you can easily import it as xml file and you can parse this xml file in Python or even in Microsoft Excel or LibreOffice.
| https://scicomp.stackexchange.com/questions/34024 |
scicomp | Defining Current Density in a FEM model (MATLAB) | I'm attempting to solve the Poisson equation in 3D for a magnetic vector potential in the presence of a current source. To validate my code, I'm initially looking to reproduce the model described in the following pair of papers:
N. Demerdash, T. Nehl and F. Fouad, "Finite element formulation and analysis of three dimensional magnetic field problems," in IEEE Transactions on Magnetics, vol. 16, no. 5, pp. 1092-1094, September 1980.
doi: 10.1109/TMAG.1980.1060817
URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=1060817&isnumber=22843
N. A. Demerdash, F. A. Fouad, T. W. Nehl and O. A. Mohammed, "Three Dimensional Finite Element Vector Potential Formulation of Magnetic Fields in Electrical Apparatus," in IEEE Transactions on Power Apparatus and Systems, vol. PAS-100, no. 8, pp. 4104-4111, Aug. 1981. doi: 10.1109/TPAS.1981.317005. URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4111101&isnumber=4111054
The paper gives the following figure to describe the coil which carries the current:
Alongside the following parameters:
20 Amps of current.
Wire is of type AWG #16 with 861 turns
Winding Height (Z axis): 8.89cm
Outer Boundary Cross Section: 15.24 cm x 15.24 cm
Inner Boundary Cross Section: 10.42 cm x 10.42 cm
I also know that the current density should be homogeneous in a specific element. In this model Jz = 0 throughout and I know J = N*I / A, where A is the cross sectional area, N the number of turns and I the current.
| VQAonline_00057591.png | Defining current density in this system can be done by considering the average current density within the winding region, $J_{0}$ (then subdividing this into elements). For winding height h, Inner cross section $L_{1}$, Outer cross section $L_{2}$ with N turns carrying current I:
$ J_{0} = \frac{IN}{h(L_{2} - L_{1})/2} $.
I note this expression does not incorporate the specific wire properties which are also specified in the paper - this maybe to allow physical reconstruction of the system rather than for the modelling side.
| https://scicomp.stackexchange.com/questions/33835 |
scicomp | Finding which triangles points are in | Suppose I have a 2D mesh consisting of nonoverlapping triangles $\{T_k\}_{k=1}^N$, and a set of points $\{p_i\}_{i=1}^M \subset \cup_{k=1}^N T_K$. What is the best way to determine which triangle each of the points lies in?
For example, in the following image we have $p_1 \in T_2$, $p_2 \in T_4$, $p_3 \in T_2$, so I would like a function $f$ that returns the list $f(p_1,p_2,p_3)=[2,4,2]$.
Matlab has the function pointlocation which does what I want for Delaunay meshes, but it fails for general meshes.
My first (dumb) thought is, for all nodes $p_i$, loop through all the triangles to find out which triangle $p_i$ is in. However, this is is extremely inefficient - you might have to loop through every triangle for every point, so it could take $O(N \cdot M)$ work.
My next thought is, for all points $p_i$, find the nearest mesh node via nearest-neighbor search, then look through triangles attached to that nearest node. In this case, the work would be $O(a\cdot M\cdot log(N))$, where $a$ is the maximum number of triangles attached to any node in the mesh. There are a couple solvable but annoying issues with this approach,
It requires implementing an efficient nearest-neighbor search (or finding a library that has it), which could be a nontrivial task.
It requires storing a list of which triangles are attached to each node, which my code is currently not set up for - right now there is just a list of node coordinates and a list of elements.
Altogether it seems inelegant, and I think there should be a better way. This must be a problem that arises a lot, so I was wondering if anyone could recommend the best way to approach finding what triangles the nodes are in, either theoretically or in terms of available libraries.
Thanks!
| VQAonline_00057446.png | The usual randomized edge hopping method should work. Basically, start with any triangle of the mesh, then determine which of the edges the target point lies on the opposite side of. That is, determine which of the edges, when extended out to a line, separate the point from the interior of the triangle. When there are two possibilities, choose one at random, and consider the triangle that is adjacent to that shared edge, and repeat. The randomization should make this method converge with probability 1 for Delaunay triangulations, and I can't think of a reason it would not work for arbitrary triangulations.
Edit: I should add that edge hopping should be $O(\log N)$ with a reasonable constant for a single point, so it would be $O(M \log N)$ for $M$ points. However, if you sort your points by locality (like using a Hilbert curve ordering first), you can initialize each new query with the triangle of the previous query, to further reduce the runtime (I'm not a CS theorist so I can't tell you what the big-O would be there).
Edit2: Found this PDF describing such a "walking" scheme that is guaranteed to terminate, and reviews the more naive approaches.
Another alternative to using quadtrees is using a Triangulation Hierarchy. See
Olivier Devillers. Improved incremental randomized Delaunay triangulation. In Proc. 14th Annu. ACM Sympos. Comput. Geom., pages 106-115, 1998.
It works best for Delaunay triangulations, but can also work for non-Delaunay.
Basically whatever you do to speed up point location will require the construction of an auxiliary data structure. In the case of quadtrees or some other spatial subdivision, you need to build the subdivision tree. In the case of edge-hopping, you need to build the triangle adjacent topological structure. The triangulation hierarchy also requires building a tree of coarser triangulations.
| https://scicomp.stackexchange.com/questions/2624 |
scicomp | Solving the heat diffusion equation with source term | I am trying to solve the 1-D heat equation numerically with a variable source term. The system is basically a tank containing styrene in which it polymerizes to liberate heat. I have assumed that the cross-section of the tank is much smaller compared to the length so any variations in the y and z directions can be neglected. I am starting with $T_0 = 313.15 \text{K}$. The domain space I am looking at is $0 \leq x\leq 5\text{m}$ and $t \geq 0$. The equations are as follows. I write the heat equation as-
$$\frac{\partial T}{\partial t} = \frac{k}{\rho C_p}\frac{\partial^2 T}{\partial x^2} + \frac{1}{\rho C_p}\left(\frac{\rho\Delta H}{MW}\frac{\partial m}{\partial t}\right)$$
The $\frac{\partial m}{\partial t}$ is basically the rate of reaction expressed in terms of the mole fraction $m$. The rate of reaction is-
$$\frac{\partial m}{\partial t} = -A\left(\frac{\rho}{MW}\right)^{\frac{3}{2}}m^{\frac{5}{2}}$$
Here:
$$k = 0.03 \hspace{8pt} \text{[cal/(s-m-K)]}$$
$$A = A_0\exp(A_1m_p + A_2m_p^2 + A_3m_p^3)$$
where:
$$m_p = 1-m$$
$$A_0 = 1.964\times10^5\exp\left(\frac{-10,040}{T}\right)$$ $$A_1 = 2.57-5.05\times10^{-3}T$$ $$A_2 = 9.56-1.76\times10^{-2}T$$ $$A_3 = -3.03+7.85\times10^{-3}T$$
The rest of the values are constants and they are-
$$\rho = 906 \hspace{6pt} \text {[g/L]}$$ $$MW = 104.15 \hspace{6pt} \text{[g/mol]}$$ $$C_p = 0.4365 \hspace{6pt} \text{[cal/g-K]}$$ $$\Delta H = -17,300 \hspace{6pt}\text{[cal/mole]}$$
The initial conditions are-
$$T = T_0$$ $$m = 1$$
The boundary conditions are-
$@ x= 0$ $$ \frac{\partial T}{\partial x} = 0, \hspace{5pt} \frac{\partial m}{\partial x} = 0$$
$@ x= 5m$ $$ \frac{\partial T}{\partial x} = 0, \hspace{5pt} \frac{\partial m}{\partial x} = 0$$
I am assuming that there is no flux at either boundary. I used the 'pdepe' command in MATLAB to solve this system of coupled PDEs. Here's the code I wrote-
clc
clear all
global rho Cp MW dH k
tspan = 60*(1:500:30000);
x = 0:0.25:5;
m = 0;
sol = pdepe(m, @pdefun, @pdeic, @pdebc, x, tspan);
u1 = sol(:,:,1);
u2 = sol(:,:,2);
surf(x,tspan,u1)
title('u_1(x,t)')
xlabel('Distance x')
ylabel('Time t')
function [c,f,s] = pdefun(x,t,u,dudx)
rho = 906;
Cp = 0.4365;
MW = 104.15;
dH = -17800;
k = 0.03;
y2 = 1-u(2);
A0 = 1.964*(10^5)*exp(-10040/u(1));
A1 = 2.57-5.05*u(1)*(10^(-3));
A2 = 9.56-1.76*u(1)*(10^(-2));
A3 = -3.03+7.85*u(1)*(10^(-3));
A = A0*exp(A1*(y2) + A2*(y2^2) + A3*(y2^3));
F = -A*((rho/MW)^(3/2))*((u(2))^(5/2));
c = [1; 1];
f = [k*rho/Cp; 0].*dudx;
s = [(dH/(MW*Cp))*F; F];
end
function u0 = pdeic(x)
u0 = [313.15; 1];
end
function [pl,ql,pr,qr] = pdebc(xl,ul,xr,ur,t)
pl = [0; 0];
ql = [1; 1];
pr = [0; 0];
qr = [1; 1];
end
The problem is that on drawing the surface plot of the temperature [u(1)], I don't see any variation with the length of the tank. This is what the surface plot looks like-
Another funny thing is that even if I change the function 'f' in 'pdefun' to garbage values like f = [65675; 767].*dudx (these numbers are meaningless, I just typed out something randomly), I get the same plot regardless of the function f. I even cleared all variables before running the code but the same thing happens. I don't understand what's going on here. Any help is appreciated.
| VQAonline_00057609.png | You are starting from a uniform temperature and you have insulated
boundary conditions; so there is no heat conduction occurring.
Likewise, your initial mole fraction is also constant in $x$ so that
the heat input is uniform along the length. So the fact that the
temperature and mole fraction don't change as a function of $x$ is
exactly what you should expect.
Another way of looking at this is: As you have defined it, this problem
could be modeled as two coupled ODE with time as the only independent variable.
| https://scicomp.stackexchange.com/questions/35729 |
scifi | Why were his vocal cords removed in Marvel's Agent Carter? | In the pilot episode of Marvel's Agent Carter, a man with his vocal cords removed was shown with a scar on his neck. Why were the vocal cords removed and why was the scar kept in such a way?
| VQAonline_00058068.png | Since the show is still in its infancy, this question is impossible to answer at the moment. However, if I were to speculate, it may just be a way of showing how ruthless both Leviathan AND its operatives are. The group is so dedicated to keeping its secrets that it will remove the vocal cords of its own operatives. AND the operatives are so loyal to the ideals of Leviathan that they're willing to sacrifice their own vocal cords.
I may be wrong, given that a certain character without vocal cords seems to have changed his mind at the last moment, but that may also be the reason that Mr. Green-Suit was after him to begin with. As it is, we'll just have to wait and see.
UPDATE: As of the show's finale, we now have an answer to this question:
The operatives in question are survivors of the Battle of Finow, and were thus exposed to the "Midnight Oil" gas accidentally invented by Howard Stark.
| https://scifi.stackexchange.com/questions/78835 |
scifi | What is the significance of the Red Comet? | For a few episodes in the show, in Season 2, there was a heavy emphasis on this Red Comet that was falling from the sky. All of a sudden it was just sort of... not a thing anymore?
What is the comet's importance and where did it suddenly disappear off to?
Or was it really just a comet?
Note: I have not yet read the books so if it's explained in there, I'd still like to know about it.
| VQAonline_00057974.png | I believe The Red Comet is what is mentioned in the prophecy of Azor Ahai
There will come a day after a long summer when the stars bleed and the cold breath of darkness falls heavy on the world. In this dread hour a warrior shall draw from the fire a burning sword. And that sword shall be Lightbringer, the Red Sword of Heroes, and he who clasps it shall be Azor Ahai come again, and the darkness shall flee before him.
The red comet -- or the bleeding star, if you will -- is the fulfilment of part of that prophecy, and it appears when Dany hatches her dragon eggs in Drogo's funeral pyre.
There are many theories and much speculation on this, and it is also related to the Prince that was promised, something that Rhaegar Targaryen was preoccupied with investigating.
It is also said
When the red star bleeds and the darkness gathers, Azor Ahai shall be born again amidst smoke and salt to wake dragons out of stone.
We can note that Daenerys has done all of these things. Her final sacrifice is also mirrored in the story of Nissa Nissa, the wife of Azor Ahai, who had to be sacrificed to make the legendary sword Lightbringer. (Yes, Melisandre tried to create a magic sword for Stannis, which she claimed was Lightbringer) Daenerys burned her husband Drogo, and Mirri Maaz Duur.
She woke the dragons from stone eggs. She was reborn in the fire (smoke). Lightbringer is her dragons.
Oh, and also, (Spoiler AFFC)
Maester Aemon became convinced of this after meeting Xhondo:Daenerys is the one, born amidst salt and smoke. The dragons prove it.
Xhondo's captain is Quhuru Mo, who met Daenerys and her dragons in Qarth (A Clash of Kings)
Q.E.D.
| https://scifi.stackexchange.com/questions/53590 |
scifi | Animation film with giant sphere-like bad "robot" | Asking community to help identify anime (animation film) from my childhood.
By the style of that animated cartoon it seems like it was from 70s or 80s, and it had Japanese picture style to it. I saw it approx. in 1994 on some local TV channel that does not exist any more. I think it called "KS video".
All I remember is that there was a boy/man hiding in some buildings or ruined sky scrapers in partially destroyed city. It was dark. He was hiding from a giant hovering robot-like thing, that looked like a giant (as tall as buildings) metal sphere with a hood-like "head" and no legs or arms. This robot was slowly hovering, scanning with creepy noise for any movement, and firing a destructive beam out of his "head". Under that hood there was no face but something glowing red or orange. If I remember correctly there was 2 of that "robots" slowly destroying the city.
Unfortunately I don't remember any more details, I have seen this on TV long time ago, but I remember that it was cool and scary animation cartoon.
I have created a rough image of how this robot looked like:
Click image to enlarge.
| VQAonline_00058877.png | I finally found it, it seems that someone here also was looking for this cartoon. I found it in suggestion section here: Anime style cartoon - 4 characters on a planet with giant oval floating robots looking for them - 1989 or before
Cartoon is called Birth aka Planet Busters aka The World of the Talisman(1984).
Aqualoid was a prosperous planet, but an attack from a mysterious life force, the Inorganics, transforms it into a post-apocalyptic shell of its former self. When Nam finds a mysterious sword, he is suddenly the object of a planet-wide chase. With the Inorganics closing in, will Nam and his friends discover the secret of the sword and save their world? Or will they destroy Aqualoid in favor of a new Birth?
| https://scifi.stackexchange.com/questions/227322 |
scifi | Unknown feature on Middle-earth's map? | On Christopher Tolkien's map of Middle-earth, one feature has always caught my eye, and to my knowledge has never been explained: The mass in the middle of the Sea of Rhûn:
Has this ever been talked or written about? Is it an island? Is it a rocky outcrop? Are they supposed to be trees? Sand? Marshes? Whatever it is, it appears to be very deliberate.
I've also noticed that many fan-made maps just ignore this feature altogether.
What is this feature in the middle of the Sea of Rhûn?
| VQAonline_00058061.png | As far as I remember, there isn't any name for it. It is an unnamed island.
The LotR Wikia says the same:
The sea also contains an unnamed island that is about thirty miles along the southeastern and northwestern coasts and twenty upon the northeastern and southwestern coasts.
Also, it must have been wooded. (thainsbook).
There has been a similar discussion on TheTolkienForum. A user contacted The Tolkien Society with the question, and here is the answer:
Hello. Sorry about the delay. A staw poll revealed that in a very
early version of the map, the Sea of Rhun had a large island in the
middle. (Unfeasibly large, given the scale of the Sea, which is very
big.) By the time the map hit publication, this had vanished and the
dots appeared.
Those who have looked carefully at the various maps point out that
there are similar dotty effects at the Mouths of Sirion and near Balar
(Silmarillion), and references to "sands" in the Sil. The dots in the
Sea of Rhun (on scale) could quite easily represent a constellation of
small islands, but are more likely to mean sands, swamp or sand bars.
(Actually small islands would make better geography on that scale.)
There appears to be no actual reference to what is going on there.
There is a discussion of this also at TheOneRing.net which adds some
details worth having. I don't however understand Quickbeam's reference
to CRT "finding later manuscripts etc." as CRT drew up this map in
co-operation with JRR while JRR was still alive and well and writing
the books - there have AFAIK been no revisions by CRT to these maps on
the basis of stuff he found after his father's death, when he started
editing the unpublished mss. Indeed, it would be against his whole
attitude of respect for his father's decisions to start "editing" LotR
material subsequent to publication. I have asked QB what he means, but
have not had a reply. As this was some time ago and you are waiting,
this is my conclusion!
I would say "be careful of taking any craft with deep draft through
these waters. You may get stuck."
Helen
Which, TBH, doesn't add much more than that there is no name to the island.
The discussion Helen references may be worth quoting for posterity:
I’ve been wondering about this for years, and now have found a few
bits of evidence in the History of Middle-earth Volume VII that gives
us a better clue.
Most all of the maps we see in today’s editions of LOTR come from the
hand of Christopher Tolkien; redrafted from his father’s originals.
Professor Tolkien altered and added to his maps as his work on the
story progressed. His original working map (the "First Map") was a
conglomeration of sections and glued bits of paper that he fussed with
for many years: "It represents an evolution, rather than a fixed state
of the geography." There was a later version called the "1943 map"
that Christopher created.
Comparing these two maps, Christopher points out a well-forested
island his father drew in the middle of the Sea of Rhûnaer, which
would later be called the Sea of Rhûn. "The island in the Sea is
coloured green on the First Map, and on the 1943 map is marked as
wooded." That’s your island right there, but in later maps it seems to
have vanished, replaced with an array of dots.
I don’t know exactly why Christopher changed it, but I suspect that
later manuscripts and maps he found showed the removal of the island.
Perhaps the discrepancy caused him to leave the dots to indicate what
was a "questionable area."
This seems to be the clearest answer, if still vague.
| https://scifi.stackexchange.com/questions/76511 |
scifi | Why was the episode "Self-Help" almost pulled? | Michael Cudlitz (Abraham) posted on Twitter that Self-Help (S05E05) was almost pulled by the network.
There have been a number of articles guessing what censors may have objected to, but they all note that they're just guesses.
Why did censors almost pull the episode?
| VQAonline_00058046.png | First, we should doubt the source, since the actors' own Twitter account can't be completely trusted (why would you pull a whole episode instead of just the controversial scene? what if it was just a promotional resource?)
Prior to the release of the episode some sources echoed Cudlitz's account and wondered if it could be violence, sex, cannibalism or the F-word.
Even after the release of the episode, it was unclear if or what was wrong with it. What could be "too much" in a show about zombies?
So my guess is, as this source says, that
Cudlitz was probably just exaggerating for the sake of a good tease
There is no official explanation from AMC, all websites you could check about the issue can't give you a plausible reason, even after the release of the episode. There is a source which stated (prior to the release) that
(The) episode of The Walking Dead would have a VERY difficult getting past the censors if they follow along with the comic book series.
But that is just more guessing. The comic event they would be referring, and that supposely might be too much for the censors would be
A flashback, in which Abraham’s family is hiding out at a grocery store when he decides to go on a supply run. When he returns, he finds that his wife and daughter have both been brutally raped and the assailants have forced his son to watch the whole thing.
But something like that probably would have been addressed by scriptwriters or executives from AMC long before a "censor" would have anything to say about the matter.
| https://scifi.stackexchange.com/questions/72541 |
scifi | Why is Wolverine's hand missing? | In the picture below it appears that (this version of) Wolverine has only got one hand and one set of claws, the other hand seems to be missing.
What happened to his missing hand and claws? How did he lose them and how does his body react to the missing piece of Adamantium?
| VQAonline_00057838.png | It is an alternate version of Wolverine from the Age of Apocalypse storylines. He is called Weapon X in that universe. The Age of Apocalypse continuum briefly replaced the current Earth-616 reality but was later retconned and redubbed Earth-295.
In the "Age of Apocalypse" story arc, the Wolverine/Logan character is again a member of the X-Men, this time using the code-name Weapon X rather than Wolverine. In this reality the events which saw the character's Adamantium ripped out have never occurred, and it is Magneto that helps him to control his feral rages. Most significantly, Weapon X is missing a hand, cut off by Cyclops (who in turn is missing an eye thanks to Weapon X). The claws on this hand still exist, however, which appear by piercing through the metal stump covering the break. Consistent with the main characterisation, this version is also shown to be a loner, his back story presenting him as an unwilling recruit to the X-Men. He and Jean Grey are lovers in this reality.
| https://scifi.stackexchange.com/questions/23365 |
scifi | Any official evidence that Rey is based on early "Star Wars" concept art? | In The Force Awakens, it would seem a lot of the "new" designs for characters and objects are, in fact, highly informed by concept art that was generated during the early stages of development on the original Star Wars.
In particular, Rey seems to be very similar to the concept art produced by Ralph McQuarrie during a period of time when the character that would become Luke Skywalker was going to be female:
Found at: www.StarWarsUnderworld.com
The article cited in the link above merely speculates that these designs were used to influence the character, but I'm looking for concrete evidence that the production team involved in designing The Force Awakens purposefully used McQuarrie designs, and the Female Luke design in particular, in their concept stage. Was this explicitly mentioned anywhere in any articles or interviews?
| VQAonline_00058250.png | Based upon the information in The Art of The Force Awakens, I'm going to say "not likely".
The book makes it clear that a number of elements, particularly locations, were based on old art by Ralph McQuarrie, but his name is never mentioned in regards to Rey's designs in any way.
The only character designs mentioned that were influenced by McQuarrie's work are Lor San Tekka (his robes are influenced by a sketch of Boba Fett) and for a "Yoda like character" that existed in the earliest stages of the concept art phase (much of this was done before a script had even been turned in, and was just the artists kicking around ideas).
Glyn Dillon seems to have done a fair bit of work on Rey's (known as Kira during pre-production) costume designs. Dillon makes specific mention of the goggles, but does not mention McQuarrie:
The idea was that we wouldn't be able to see who Kira was; we wouldn't know if she were a man, a woman, an alien, or something else entirely. And I thought it would be great fun to have her fashion her own goggles out of scavenged stormtrooper lenses. (page 161)
If McQuarrie's old art was an influence, and it's definitely possible since the artists were combing through the archives, it was likely something subconscious amongst the artists.
| https://scifi.stackexchange.com/questions/111103 |
skeptics | Do vaginal tightening creams work? | From a billboard in Ulaanbaatar, Mongolia (population 1.4 million)
Vagina Tight
залуужуулах цогц эмчилгээ [Google translate from Mongolian into English: comprehensive rejuvenation treatment]
(I think it is talking about creams - I might be wrong and it's talking about surgery, but the following is definitely talking about creams)
'Feel tight and wanted again!' The disturbing 'vaginal shrinking' creams that promise to make you feel like a virgin again from the Daily Mail gives more information on vaginal tightening creams. It says that there are several of them, and that some people say they work, and some people say they don't work
'Recapture your vagina's youth so you can feel tight and wanted again'
- the slogan accompanying one of several creams currently on the market which claim to 'shrink' and 'tighten' your lady bits.
...
18 Again, with its acid pink branding, isn't the only cream in its
category. None of them appear to be FDA approved, but this is not a
legal requirement for companies selling such products.
...
Tellingly, the product reviews on Amazon are extremely polarized, as
with all of the other similar creams; with ratings of either five
stars or one. 'You do become tight and stay tight. Worth the money,'
one review reads. 'I tried it and not only did it not work whatsoever,
but it also caused me to get a bladder infection and a yeast
infection,' reads another.
Some pages talk about whether tightening creams work or not, but they don't seem that reliable. For example Do Vagina Tightening Creams Really Work? and Here Are the Real and Ridiculous Reviews for Vaginal Shrinking Cream. One product's site has a page titled Clinical Trials, which talks about a "Prospective, Randomized, Double-Blind, Placebo controlled Pilot Trial of the efficacy and safety of PK24® for women with vaginal wall relaxation", but the page doesn't indicate how the control group fared.
Can you tighten your vagina with one of these creams?
| VQAonline_00059396.png | The answer is "probably not". An in-depth medical review here has some exceedingly good points about why. To summarize the main factors: vaginal tightness is mainly controlled by deeper layers of muscle in the pelvic floor, which most topical creams will not easily penetrate to. There is also little to no evidence that the ingredients in these creams increase blood flow to the targeted muscles, or any other effects that may aid in muscle tone improvement.
Many of the ingredients do have astringent properties, which will cause a sensation of tightness for the user, similar to mouth pucker. They are also likely to mess up the microbiome of the user, leading to additional discomfort. Since generally vaginal tightness can be inversely correlated with relaxation and arousal, being uncomfortable physically or emotionally could certainly make the orifice feel tighter, so that may be part of the explanation.
Another part of the issue is that many of these products' usage guidelines state that after application you also perform vaginal strengthening exercises. The cream itself is likely not contributing to the positive improvements reported by some, and instead the muscle strengthening is the actual helpful factor.
| https://skeptics.stackexchange.com/questions/37388 |
skeptics | Did Einstein say this about his marriage? | I found a picture with a quote on facebook today quoting Einstein.
The quote states:
When we first got married, we made a pact. It was this:In our life together, it was decided I would make all of the big decisions and my wife would make all of the little decisions. For fifty years, we have held true to that agreement. I believe that is the reason for the success in our marriage. However, the strange thing is that in fifty years, there hasn't been one big decision.
Is there any truth to that he actually said this? (Given that he did divorce once)
| VQAonline_00059339.png | Very unlikely. This is sometimes attributed to Einstein on his 50th Wedding anniversary
Einstein was married twice:
The first marriage was to Mileva Marić, from January 1903 until their divorce on 14 February 1919 - i.e. 16 years of marriage.
The second marriage was to Elsa Löwenthal on 2 June 1919 until her death in December 1936 - i.e. 17 years of marriage.
[I used Wikipedia as a source, as I don't think these dates are in dispute.]
He never had a 50th wedding anniversary, and he never had an opportunity to say "in fifty years, there hasn't been one big decision."
This doesn't prove the quote isn't a distorted version of something he did say.
| https://skeptics.stackexchange.com/questions/34322 |
skeptics | Did New York Times post this Hitler apology stating Jews baited the Nazis by trying to fight back on June 15, 1934? | Post from Revolution News reads,
"By hating Hitler and trying to fight back, Jews are only increasing the severity of his policies against them.
"If Jews throughout the world try to instill into the minds of Hitler and his supporters recognition of the ideals for which the race stands, and if Jews appeal to the German sense of justice and the German national conscience, I am sure the problem will be solved more effectively and earlier than otherwise."
| VQAonline_00059456.png | As the source of the image says, it’s from the June 15, 1934 issue of The New York Times. Here’s a screenshot of the article, "URGES GOOD WILL BY JEWS FOR NAZIS" by Henry J. Cadbury the Professor of Biblical Literature of Bryn Mawr College. Here is the article in full, with the quote from the question being under "Urges Appeal to Justice":
URGES GOOD WILL BY JEWS FOR NAZIS
Prof. Cadbury of Society of Friends Says It Will Gain More Than Will Hate
DECRIES BOYCOTT AS 'WAR'
Dr. Goldenson Tells Session of Rabbis a Minority Must Not Use Tactics of Foes
Special to The New York Times
Wernersville, PA., June 14 — Good will, not hate or reprisals, will end, or offset, the evils of the Hitler government’s persecution of Jews, Professor Henry J. Cadbury, Professor of Biblical Literature at Bryn Mawr College, told the Central Conference of American Rabbis as it opened its convention here today.
The message as president of the conference was delivered tonight by the Rev. Dr. Samuel H. Goldenson, rabbi of Temple Emanu-El, New York.
Professor Cadbury is chairman of the service committee, American Society of Friends.
“Oppression of Jews in German by Hitler and his Nazi forces can be ended not by hate that their victims may display, or by attempts to fight back,” he said, “but by efforts to cultivate good will.”
“You can prove to your oppressors that their objectives and methods are not only wrong, but unavailing in the face of the world’s protests and universal disapproval of the injustices the Hitler program entails.
Urges Appeal to Justice
“By hating Hitler and trying to fight back, Jews are only increasing the severity of his policies against them.”
“If Jews throughout the world try to instill into the minds of Hitler and his supporters recognition of the ideals for which the race stands, and if Jews appeal to the German sense of Justice and German national conscience, I am sure the problem will be solved more effectively and earlier than otherwise.”
Professor Cadbury declared “it is the duty of Christians the world over to help right the injustices wrought by the Nazis.”
“Every God-believing Christian, in any nation,” he said, “should join in trying to atone for the wrongdoings done Jewish people, if only for the sake of their own Christian beliefs and Christian doctrines of universal goodwill and brotherhood.”
The boycott against German, he asserted, is not an effective means of meeting the evil.
“Boycotts are simply war without bloodshed,” he said, “and war in any form is not they way to right the wrongs being inflicted on the Jewish people.”
Goldenson Prescribes Remedy.
Hitler and what he symbolizes are spiritually contemporary with the Inquisition, although he uses modern means to “distill his poison,” Dr. Goldenson said in his message.
But he warned that the remedy against Hitlerism and the protection for minority groups lay not in a mere denunciation but “in the improvement of social conditions and relations wherever we live.”
As a foundation for this task he urged support for a program among Jews looking to “the revitalization of religious faith and reconsecration to ethical and spiritual ideals.”
Dr. Goldenson pointed out that “men like Hitler unfortunately are always present in the world, at any rate potentially,” adding:
“It is only when their fellows are greatly disturbed, defeated and frustrated that they become a prey to demagogues and false messiahs.”
He described the dangers inherent in the adoption by minorities of “the methods that seem to have made their enemies successful.”
“Should illiberalism develop in America,” he added, “it would most certainly show itself the denial of the humane and democratic principles upon which our government is founded an in the substitution of ideas not unlike those that are used to explain and to justify the German persecutions and atrocities.”
“Realizing then, as everyone must, that in the spread of intolerance we Jews are always the first victims, it behooves us to be especially watchful of our own conduct and not commit the folly of believing that similar illiberalism may not develop even among ourselves.”
“Everywhere there is a cry for Jewish solidarity. It is unquestionably important that especially in these threatening times we should think and act together. But solidarity will not serve us, as it does not serve the world at large, unless it is the result of critical thinking and of clearly conceived and completely justified objectives.”
“What is not quite so easy to understand is that Jewish likemindedness has always been derived from an adequate appreciation of the meaning of our history and the content of our literature. Unless we are informed upon our heritage, no Jewish standards can be developed, and when no such standards are developed, Jewish solidarity is certain to become nothing more than brute gregariousness in the hours when clouds gather and storms threaten.”
“We have already seen the signs of havoc wrought by uninformed and uncritical solidarity in our midst. In many cities our people have been called together by self-appointed leaders for the assertion of Jewish rights and for the promotion of special programs and objectives. the appeal has almost invariably been made in the name of Jewish solidarity.”
“Such an appeal, we should be reminded, is not unlike that of the superpatriots who frequently go so far as to insinuate that, if one does not heed their call, it is a certain sign of disloyalty to one’s people and to one’s country.”
Aid Program Should Be United
One of the tasks which should not be clouded by differences, Dr. Goldenson added, is helping German Jews to reach a haven wherever one is offered.
Jews, Dr. Goldenson said, “should wish to give the world more than successful careers.”
“Our bankers, commercial and industrial leaders, movie magnates, doctors, lawyers, scientists, and artists,” he said, “should in their respective fields so conduct their affairs as to body forth some added benefaction to their neighbors.”
Stressing the need for the development of spiritual values, he said he “would suggest that all our religious forces unite upon a program looking for the revival of Jewish interest and learning and for the stimulation of Jewish loyalties and idealism.”
“The Synagogue Council fo America, representing the three religious groups in our midst, may well make this program its primary business,” he proceeded.
“In recent years our people have become specialist in the art of conducting campaigns. We have managed many successful drives for relief, philanthropy and general social welfare. The time has come to use our expert knowledge as campaigners for the most vital need of our people and our day, the revitalization of religious faith and the reconsecration to ethical and spiritual ideals.”
“Why may not the week of Chanukah be used for such a campaign?”
In line with this program, Dr. Goldenson urged also the establishment of a weekly paper “whose sole purpose should be the dissemination of the knowledge of Judaism.”
He stressed the importance of revising the liturgy.
Calls for Adult Education
Rabbi Abraham J. Feldman of Hartford, Conn., said that adults as well as children need education. As chairman of the educational committee he said religious education alone is not sufficient.
“Parents as well as their children must be urged to educate themselves, broaden their vision, and enlarge their objectives in life,” he declared.
Speaking of adult Jewish education, Dr. Leon Fram of Detroit urged through study of Jewish history and exhorted Jewish parents to set an example to their children in seeking higher education and in developing Jewish cultural aims and ideals.
Such a course, he said, will increase respect for Jewish schools. Twenty-five large schools in various cities are now giving advanced instruction to over 5,000 adults he reported.
Rabbi Morton M. Berman, director of Jewish education of the Free Synagogues of America, declared Judaism is something more than a religion.
“Acceptance of this view ought to bring about a revolution in studies and in methods in Jewish schools,” he proceeded.
“Palestine is the centre of Jewish civilization, not merely the remote ancestral home of the Jew. Jewish children should be taught more about Jews, their history and their religious and social tenets.”
(If you prefer to look at images of the full original article, the quote starts at the bottom left of this first image and continues at the top left of the second.)
| https://skeptics.stackexchange.com/questions/41580 |
skeptics | Did Morgan Freeman say "Oppression is being told you can't say certain words because you will offend someone else"? |
A friend sent me an image of Morgan Freeman with the following phrase as subtitle, assuring that the man himself said it:
"Oppression is not hearing a word that offends you. Oppression is being told you can't say certain words because you will offend someone else"
But when I googled it, I could only find posts related to this tweet, so I'm assuming this woman said it, not Morgan Freeman. But when I said that to my friend, he insisted Mr. Freeman said it first.
So, does anyone know for a fact if Morgan Freeman said this phrase?
| VQAonline_00059424.png | Going through all of Morgan Freeman's quotes in the website BrainyQuote, he didn't say this, but this was said by Blaire White (random YouTuber).
source: All of Morgan Freeman's Quotes
| https://skeptics.stackexchange.com/questions/39070 |
skeptics | Has California built only 1 University since 1980? | Kambree Kawahine Koa posted this image:
Has California built only 1 University since 1980?
| VQAonline_00059406.png | No, this Huff Post article* which repeats the claim was corrected to say that it considers only University of California system:
Correction: [...] Language has also been amended to indicate that the article is considering the University of California system, and not the California State University system.
The University of California system indeed opened only one new campus since 1980, UC Merced, which started working in 2003-2004:
Faculty members began to arrive in 2003 with graduate students in tow and began setting up research laboratories and programs at UC Merced's ancillary research facility on the former Castle Air Force Base, biding their time until buildings were ready on campus. The first graduate courses began in fall 2004.
But, the California State University program opened another 3 universities in that time:
CSUSM:
1989: Governor George Deukmejian signs Senate Bill 365 into law. The bill officially reconstitutes the SDSU satellite campus as California State University San Marcos — the first comprehensive U.S. university to be founded in two decades, and the 20th campus in the CSU system. Bill W. Stacy is named the university’s first president and is tasked with recruiting 12 founding faculty members.
CSUMB:
Founded in 1994 on the former site of Fort Ord by educators and community leaders, Cal State Monterey Bay faculty and staff build on that legacy as we explore innovative ways to meet the needs of a new generation of students while simultaneously powering the Monterey County economy.
CSUCI:
Established in 2002, we’re the youngest of 23 campuses in the CSU family.
During that time at 7 new community colleges were opened in California:
Clovis Community College:
Clovis Community College was originally opened as a center in 2007, with the 80,000 square foot Academic Center One complex
Folsom Lake College
Folsom Lake College was established in 2004 as the fourth campus of the Los Rios Community College District
Irvine Valley College:
Irvine Valley College, established in 1985 in Irvine
Moreno Valley College:
The Moreno Valley and Norco Campuses, opened in March 1991, have grown rapidly and were granted initial accreditation in January 2010
Norco College:
Norco College opened to students in 1991
Santiago Canyon College:
Santiago Canyon College (SCC), established in 1985
West Hills College Lemoore:
West Hills College Lemoore was established in 2002
There are some community colleges which were opened before 1980, but became part of the California Community Colleges system after 1980.
In addition, according to the List of colleges and universities in California wikipedia page 37 private institutions opened since 1980 (of those two have been since closed and one is unaccredited).
* - The original claim seems to come from Business Insider, but appears without any correction or clarification, see here (dated Jun. 13, 2012) and here (dated Apr. 12, 2012)
| https://skeptics.stackexchange.com/questions/37834 |
skeptics | Was the quantity of Fentanyl imported in 2018 enough to kill every American? | ABC reporter Meridith McGraw, who covers the White House, recently tweeted:
Inbox: For a payment of $20.20, the Trump campaign says they will send a “faux brick” to Pelosi and Schumer’s offices “with facts about the need for border security and an appeal to “TEXT ‘WALL’ to 88022.”
The brick reads:
TEXT "WALL" TO 88022
2018: FENTANYL AT THE BORDER
ENOUGH ENTERED U.S, TO KILL EVERY AMERICAN
This tweet was notable enough to be picked up by The Week,
Did enough Fentanyl get (illegally?) imported to the US in 2018 to kill every (US) American?
| VQAonline_00059481.png | According to Fentanyl seizures at US-Mexico border up 750 percent:
The amount of fentanyl seized by border agents has skyrocketed in recent years, from two pounds in fiscal year 2013 to approximately 1,485 pounds from Oct. 1, 2016, to Sept. 30, 2017
Matthew Barden of the Drug Enforcement Administration is cited as saying:
300 pounds of fentanyl is lethal enough to kill about 100 million people
So enough fentanyl was seized by border agents in FY2017 to kill every American. Plus, obviously not all the fentanyl is interdicted. As long as 2018 amounts are at least as much as FY2017, the claim is defensible.
| https://skeptics.stackexchange.com/questions/43246 |
skeptics | Is this a way to survive a lightning strike? |
source
Text in the image (clockwise):
Crouch down low like a baseball catcher. Get as low as you can. The nearer
you are to the ground, the less likely you are to be struck by lightning. But never lie down!
If your hair begins to stand on end or your skin starts to tingle, a lightning strike is imminent. Immediately get into the crouching position. Lightning may strike without this warning, however.
Place hands over ears to minimize hearing loss from the loud clap of thunder that will boom very close to you.
The only thing touching the ground should be the balls of your feet. Lightning can hit the ground first, and then enter your body. The more you minimize your contact with the ground, the less chance of electricity entering your body.
Touch the heels of your feet together. If electricity from a ground strike enters through your feet, this increases the chances of the electricity going in one foot and out the other, rather than into the rest of your body.
Don't touch any possible conductors.
| VQAonline_00059223.png | It's a bit of a stretch. FEMA describes most of that advice as a last resort: if you feel a tingle, and you are in the open, then assume that position, meant to minimize damage.
On the other hand, FEMA and all other sources that I've seen clearly spell out that you need to find shelter, and that's the best way to ensure your safety.
If you feel your hair stand on end (which implies that lightning is about to strike), squat low to the ground on
the balls of your feet. Place your hands over your ears and your head between your knees. Make yourself the
smallest target possible and minimize your contact with the ground. DO NOT lie flat on the ground.
Ready.gov agrees:
During Thunderstorms and Lightning
If thunderstorm and lightning are occurring in your area, you should:
[...]
Avoid hilltops, open fields, the beach or a boat on the water.
Take shelter in a sturdy building. Avoid isolated sheds or other small structures in open areas.
A good summary on how to survive a lightning storm is provided by [Live Science]
How to survive a lightning strike
The best way to survive, of course, is to avoid a lightning strike.
The Federal Emergency Management Agency (FEMA) recommends people
follow the 30/30 rule: If, after seeing lightning, you can't count to
30 before hearing thunder, get inside a building immediately (because
the lightning storm is close). And don't go outside until 30 minutes
after the last clap of thunder.
[...]
If you're caught outdoors in a forest during a lightning storm, seek
shelter in a low area under a dense growth of small trees. Avoid tall
trees, since lightning tends to strike the tallest object in an area.
If you're in an open area, go to a low area, like a valley or a ravine
(but be alert for flash floods). If you're in a boat in open water,
get to land as quickly as possible.
And if you feel your hair stand on end, that means lightning is about
to strike. As a last resort, immediately squat down on the balls of
your feet, cover your ears with your hands (to minimize hearing loss)
and put your head between your knees.
(my emphasis)
How to Survive a Lightning Strike
| https://skeptics.stackexchange.com/questions/22430 |
spanish | Análisis sintáctico de una oración muy compleja (con un árbol) | Estoy tratando de analizar las oraciones en la frase :
me temo que el agua fresca no sea la mejor solución para curar la quemadura que se hizo con la cacerola llena de aceite hirviendo
Pero después de unos días, mi mente se volvió en una tostada... Estoy muy inseguro sobre la calidad de este análisis.
Si alguién tiene el coraje de ayudarme diciéndome lo que es falso y lo que es correcto, usted será un shah.
Cordialmente.
| VQAonline_00059705.png | Tu análisis parece bastante correcto. Lo mejor en estos casos es ir descomponiendo el problema en partes más pequeñas, con la vieja táctica de "divide y vencerás". Así que vamos allá.
Me temo que el agua fresca no sea la mejor solución para curar la quemadura que se hizo con la cacerola llena de aceite hirviendo.
La primera frase es:
Me temo X.
Aquí se usa el verbo temer, que es transitivo y usado más como pronominal, de ahí el me inicial. Así que X es el complemento directo de la oración. Descompongamos X:
El agua fresca no es Y.
Cambio el verbo a indicativo para mejor comprensión de la frase. Aquí la estructura es sencilla: oración copulativa tipo "X [no] es Y", donde Y es el atributo de X. Descompongamos Y:
La mejor solución para Z.
Aquí tenemos un sintagma nominal la mejor solución, seguida de Z que, como bien has dicho, en este caso es una oración subordinada sustantiva con el verbo en infinitivo (equivaldría a "la mejor solución para eso"), introducida por para en su acepción 4. Descomponemos Z:
[...] cura la quemadura W.
Cambio el verbo y supongo un sujeto elidido. Analizando, aquí W sería un complemento adjetival de quemadura, que a su vez sería el complemento directo de curar, verbo transitivo. Descomponemos W:
Se la hizo con la cacerola llena de aceite hirviendo.
La preposición con denota el medio, modo o instrumento que sirve para hacer algo, por lo que efectivamente introduce un complemento circunstancial de modo. ¿Cómo se hizo la quemadura? Con la cacerola de aceite hirviendo. A partir de aquí ya no tenemos más frases subordinadas. Simplemente hirviendo es el adjetivo de aceite, llena es adjetivo de cacerola, y de aceite hirviendo es un sintagma preposicional que complementa al adjetivo llena.
| https://spanish.stackexchange.com/questions/35708 |
spanish | ¿De dónde viene la expresión "dar sopas con honda"? | Es curioso que yo siempre he pensado que la expresión era "dar sopa con ondas", creo que desde que leí este cómic de Astérix:
Sin embargo, descubro en el diccionario que la expresión es, en realidad:
dar sopas con honda alguien o algo a otra persona o cosa
loc. verb. coloq. Mostrar una superioridad abrumadora sobre ella.
Buscando en Google parece, en todo caso, que la forma "sopa con ondas" tiene más popularidad que la original "sopas con honda". Así pues, ¿cuál es la forma correcta? ¿De dónde viene?
| VQAonline_00059683.png | Desde luego, ni lo de tirar pedazos de pan empapados en un líquido usando un arma ni lo de crear ondulaciones en un caldo parece tener mucho sentido. Sin embargo, todo cobra más sentido si nos fijamos en esta acepción:
sopa de arroyo
f. coloq. desus. Piedra suelta o guijarro.
Esta acepción, hoy en desuso, estaba vigente hace algunos siglos, como atestiguó el Autoridades en 1739:
SOPA DE ARROYO. En estilo festivo llaman à la piedra suelta, ò guijarro; porque en los arroyos suelen estar unas veces en seco, y otras mojadas, conforme crece, ò mengua el agua de ellos.
Se recoge su uso en la segunda parte del Quijote:
Asaz de locura sería intentar tal empresa: considere vuesa merced, señor mío, que para sopa de arroyo y tente bonete no hay arma defensiva en el mundo, sino es embutirse y encerrarse en una campana de bronce [...].
Se entiende pues el origen: aquel que sea capaz de darle con un guijarro y una honda al oponente es el que demostrará mayor pericia.
En todo caso, la expresión parece relativamente reciente en comparación. El primer caso que encuentro es en la hemeroteca de la BNE:
Y luego, al final, vendrá la lucha con el traidor, que aunque le dé sopas con honda, tendrá que dejarse vencer, porque si no el director se cabrea.
Muchas gracias (Madrid). 13/10/1928, n.º 244, página 8.
En la misma hemeroteca es en 1979 cuando aparece el primer caso de la versión "sopa con ondas". Curiosamente, la versión "sopas con onda" aparece en la misma publicación que la citada anteriormente:
Con el Extraordinario de Primavera, vamos a dar sopas con onda a la Vie Parisienne.
Muchas gracias (Madrid). 28/3/1925, n.º 61, página 15.
Por lo cual se ve que la confusión honda/onda existió desde el primer momento.
| https://spanish.stackexchange.com/questions/30622 |
spanish | Understanding a cartoon | I was recently shown the Spanish cartoon below and I'm having trouble understanding it. When I translate it directly, I get:
I am turning myself off!
I am turning myself off!
I don't have a connection!
I understand that "me apago" is an usual use of apagar, which can be inferred as both I am dimming myself (extinguishing myself) and as I am turning myself off. However, I just don't understand the comical side of the cartoon/what is the bigger picture.
| VQAonline_00059604.png | I believe the humor behind this particular cartoon is that this man can no longer think by himself and is depending upon an Internet connection for him to perform the most basic brain functions such as "staying on".
While "me apago" could be correctly translated as "I am turning myself off" in this particular context is more like "I am powering off". When you turn on an electrical device you are "powering it on", when you turn it off you are "powering it off". As mentioned by Jdamian, this would be akin to "I am shutting down" which was what I was looking for when writing this answer.
"No tengo conexión" is frequently used to express "I have no Internet connection" or "I have no phone service".
So, I am assuming in this context he (or his brain) is expressing "I am powering off (I am shutting down), I have no internet connection". He is expressing this in an anxious manner, so this cartoon might be trying to make fun of how nowadays people can't do anything unless they are connected to the Internet because they can't think for themselves. It's obviously an exaggeration, of course.
If there is more to this cartoon (like other panels, a caption, a tool-tip, etc.) please share it, it might help to understand its meaning since the punchline could be hidden there.
Update: Thanks to fedorqui, it is clear that there is no hidden punchline for this cartoon. I had suspected the author was making fun of younger generations for their inability to do anything without an Internet connection but I refrained from adding such conclusion since there was no proof that the author would be of an older generation (I didn't know it was El Roto); however, it appears my suspicions were not far off.
| https://spanish.stackexchange.com/questions/19064 |
spanish | ¿Qué palabra se usa para describir cuando un pago cubre hasta cierta fecha? | Soy el autor de una aplicación de computadora para administrar Casas de Empeños en Puerto Rico. Cuando un cliente debe tres meses de intereses, podría perder la prenda, pero si solo paga dos meses de intereses, el cliente se queda atrasado un mes para poner los intereses al día.
Ejemplo: El cliente empeñó una prenda el 1-feb-2012. Tres meses después, en 1-may-2012, el cliente solo pagó 2 meses de intereses y esta pago hasta 1-abr-2012. Yo estoy definiendo esta fecha como "Fecha de Vigencia". ¿Hay alguna palabra que describa mejor esta fecha?
He aquí un ejemplo de pantalla de transacciones:
| VQAonline_00059546.png | Yo trabajo en un equipo de Payroll para US/Canada en Accenture y solemos tratar con este tipo de formas todo el día. Creo que lo más adecuado debería de ser no la mejor traducción literal, sino la mejor expresión de la idea para que al usuario le quede claro y el programa sea intuitivo. Yo buscaría soluciones más cortas y simples como:
Último pago
Último interés
Interes pago en:
Interes pagado:
Pago efectivo desde:
Último pago entrado
Última entrada
Último plazo pagado
Último check in
etc. Combinaciones hay miles.
En realidad sacaría las palabras que se dan por sobrentendidas: Si estás en una pantalla de -plazos-, se sobrentiende que "último pago" es del plazo. Y así sucesivamente: si estás en una pantalla de "alquiler", "último pago" es del alquiler, o "último alquiler", al ser fecha se sobrentiende que es el último pago.
Es más, te recomiendo usar abreviaturas para palabras comunes en gente que se dedica a finanzas, o ni siquiera:
Últ. pago
Úmo. pago
| https://spanish.stackexchange.com/questions/2474 |
spanish | ¿Cuál es el mejor término para traducir la palabra "nice" en un contexto de Matemáticas? | ¡Hola!
Estos días comencé a trabajar con mi tesina y me encontré con un término para el cual no acabo de encontrar una buena traducción al español sin que se pierda la seriedad del trabajo o que quede muy fuera de lugar. El término aparece en la siguiente oración
A maximal locally finite cellular family of open sets is called nice.
Dicha oración viene en la siguiente imagen que a su vez es un extracto del artículo que se puede encontrar aquí
En pocos términos, dice que cuando una familia de de abiertos es maximal, localmente finita y celular es llamada nice. Hasta ahora, en la redacción de mi trabajo me he referido a estas familias como familias nice pero obviamente queda muy fuera de lugar. Intenté con familia óptima, buena familia, pero siento que es mala la traducción porque a veces se usan precisamente las palabras óptima y buena como adjetivos en este contexto y solo causaría confusión. ¿Hay algún término que sea mejor que pudieran sugerirme?
Gracias por leerme.
| VQAonline_00059714.png | En esta tesis doctoral en español la autora usa el término nice 312 veces sin despeinarse.
Inventarte un término que no sea del agrado de algún miembro del tribunal puede ser desastroso. Ya llegará el momento en el que puedas sentar cátedra. Si ni tú ni tu director de tesina habéis visto una traducción ya establecida, yo preguntaría a otros profesores e indagaría por foros de matemáticas. Y si no encuentras ninguna publicación en la que te puedas apoyar, mejor lo dejas sin traducir.
Eso sí, yo lo escribiría en cursiva todas las veces.
| https://spanish.stackexchange.com/questions/37835 |