OpenLLM-France/wikimedia huggingface dataset:
# Electronics/Noise in electronic circuits
## Electrical Noise

    any unwanted form of energy tending to interfere with the proper and easy reception and reproduction of wanted signals.

## Classification
### Based on Origin

* External noise
** Atmospheric
** Extraterrestrial
*** solar
*** Cosmic
** Industrial
* Internal noise
** Thermal Agitation Noise
** Shot Noise
** Transit Time Noise
** Flicker Noise
** Miscellaneous Sources

#### Thermal noise
##### Thermal Agitation Noise

    Also known as Johnson noise or White noise.
$P_{n}\propto \ T\;\delta \!f=k\,T\;\delta \!f$
where k = Boltzmann's constant = 1.38x10$^{-23}$J/K
       T = absolute temperature, K = 273 + °C
       δ f = bandwidth of interest
       P$_n$ = maximum noise power output of a resistor
$P_{n}={\frac {V^{2}}{R_{L}}}={\frac {\left({\frac {V_{n}}{2}}\right)^{2}}{R}}={\frac {V_{n}^{2}}{4R}}$
$V_{n}^{2}=4RP_{n}=4RkT\;\delta \!f$
$V_{n}={\sqrt {4kT\;\delta \!f\;R}}$

#### Shot Noise

$i_{n}={\sqrt {2ei_{p}\;\delta \!f}}$
where i$_n$ = r.m.s. shot-noise current
    e = charge of an electron = 1.6x10$^{-19}$C
    i$_p$ = direct diode current
    δ f = bandwidth of system

## Noise Calculations
#### Addition due to several sources

noise voltages:
$V_{n}1={\sqrt {4kT\,\delta \!f\,R_{1}}}$
$V_{n}2={\sqrt {4kT\,\delta \!f\,R_{2}}}$
$V_{n,tot}={\sqrt {{V_{n}1^{2}}+{V_{n}2^{2}}+...}}={\sqrt {4kT\,\delta \!f\,R_{tot}}}$
where R$_{tot}$ = R$_1$+R$_2$+...

#### Addition due to Cascaded Amplifier stages

$R_{eq}=R_{1}+{\frac {R_{2}}{A_{1}^{2}}}+{\frac {R_{3}}{{A_{1}^{2}}{A_{2}^{2}}}}$

## Methods of reducing noise
### Differential signaling

Differential signaling is a method of transmitting information electrically by means of two complementary signals sent on two separate wires. The technique can be used for both analogue signaling, as in some audio systems, and digital signaling, as in RS-422, RS-485, PCI Express and USB.

### Good grounding

An ideal signal ground maintains zero voltage regardless of how much electrical current flows into ground or out of ground.
When low-level signals travel near high currents, their return currents shouldn't be allowed to flow in the same conductor. Otherwise, noise such as AC ripple on the high current will modulate the low-level signal.

## References

Kennedy, George 'Electronic Communication Systems' , 3rd Ed. ISBN 0-07-034054-4
# Electronics/Op-Amps/Non Linear Configurations/Inductor Gyrator
## Operation

Simulates an inductor (i.e., provides inductance without the use of a possibly costly inductor). The circuit exploits the fact that the current flowing through a capacitor behaves through time as the voltage across an inductor. The capacitor used in this circuit is smaller than the inductor it simulates and its capacitance is less subject to changes in value due to environmental changes.
This circuit is unsuitable for applications relying on the back EMF property of an inductor as this will be limited in a gyrator circuit to the voltage supplies of the op-amp.
# Electronics/Motors

Most electrical motors are induction based.
They work either through the flow of electricity or turing a magnet.
Waterfalls and windmills work by turning a magnet. Waterfalls tend to have even power, but windmills have odd erratic power based on the wind.
The driving force that turns the rotor containing the magnets is called the "Prime Mover"
Generators work by supplying current that drives a turbine.
Induction based motors work on AC and spinning magnets.
One of the problems of induction based motors is most of their power is reactive (caught in a magnetic field). Capacitors are required to make the power real. It is common in induction based generators to have a bank of variable capacitors to try to keep the power as real as possible.
# Haskell/Hierarchical libraries/Lists

* Lists (Solutions)
* Libraries Reference
* Introduction
* Maybe IO Random
* Data structures primer
* Arrays Maps
The List datatype (see Data.List) is the fundamental data structure in Haskell — this is the basic building-block of data storage and manipulation. In computer science terms it is a singly-linked list. In the hierarchical library system the List module is stored in Data.List; but this module only contains utility functions. The definition of list itself is integral to the Haskell language.

## Theory

A singly-linked list is a set of values in a defined order. The list can only be traversed in one direction (i.e., you cannot move back and forth through the list like tape in a cassette machine).
The list of the first 5 positive integers is written as
We can move through this list, examining and changing values, from left to right, but not in the other direction. This means that the list
is not just a trivial change in perspective from the previous list, but the result of significant computation (O(n) in the length of the list).

## Definition

The polymorphic list datatype can be defined with the following recursive definition:
The "base case" for this definition is, the empty list. In order to put something into this list, we use the (:) constructor
The (:) (pronounced cons) is right-associative, so that creating multi-element lists can be done like
or even just

## Basic list usage
### Prepending

It's easy to hard-code lists without cons, but run-time list creation will use cons. For example, to push an argument onto a simulated stack, we would use:

### Pattern-matching

If we want to examine the top of the stack, we would typically use a peek function. We can try pattern-matching for this.
The a before the cons in the pattern matches the head of the list. The as matches the tail of the list. Since we don't actually want the tail (and it's not referenced anywhere else in the code), we can tell the compiler this explicitly, by using a wild-card match, in the form of an underscore:

## List utilities

FIXME: is this not covered in the chapter on list manipulation?

### Length, head, tail etc.

* Lists
* Solutions to exercises
* Libraries Reference
* Introduction
* >> Maybe >> IO >> Random
* >> Data structures primer
* >> Arrays >> Maps
* Haskell
* Haskell Basics
* >> Elementary Haskell
* >> Intermediate Haskell
* >> Monads
* Advanced Haskell
* >> Fun with Types
* >> Wider Theory
* >> Haskell Performance
* Libraries Reference
* >> General Practices
* >> Specialised Tasks
# Haskell/GUI/Chapter

Specialised Tasks
# English-Hanzi/Taiwan

Special:search/Taiwan prefix:English-Hanzi/
Taiwan is a province of China. It is governed by the Republic of China. Taiwan is to the east of Chinese Mainland. Its population is 23.6 million.
台湾 是 中国 的 一个 省份。它 由 中华民国 统治。台湾 在 中国大陆 以东。它的 人口 是 2360万。
# English-Hanzi/Surgery

Surgery is needed only if the cataracts are causing problems and generally results in an improved quality of life.
仅在白内障引起问题并通常改善生活质量时才需要手术。
# English-Hanzi/Sydney

Sydney is the capital of New South Wales. It has a population of 5.2 million. It is the city of largest population in Australia and Oceania.
悉尼是新南威尔士州的首府。 它的人口为520万。 它是澳大利亚和大洋洲人口最多的城市。
# English-Hanzi/System

A system is an organized thing.
一个 系统 是 一个 有组织的 东西。
# English-Hanzi/Tanzania

Tanzania is a country in the east of Africa. Its population is 56 million. Its capital is Dodoma.
Tanzania是一个在非洲东部的国家。它的人口是5600万。它的首都是Dodoma。
# English-Hanzi/Survivor

Vesna Vulovic, an air stewardess who survived the highest ever fall by a human being after her plane broke up at 10,000m, has died aged 66.
Vesna Vulovic 逝世，享年 66岁，曾经 是 空中小姐 时，她的 飞机 在 一万米 高空 解体，是 人类 从 最高处 坠下 的 生还者。
# English-Hanzi/Sushi

Sushi is a kind of food originated from Japan. It is a kind of rolls made of rice, seafood, meat, vegetables, and so on.
寿司 是 源自 日本 的 一种 食物。它 是 一种 饭卷，用 米饭，海鲜，肉类，蔬菜 等 制成。
# English-Hanzi/Symbol

A symbol is a mark that is used to represent something.
符号 是 用来 表示 某事物 的 标记。
# English-Hanzi/Switzerland

Switzerland is a landlocked country in the west of Europe.
瑞士是欧洲西部的一个内陆国家。
# English-Hanzi/Symptom

Special:search/symptom prefix:English-Hanzi/
Symptom is the sign of illness.
症状 是 疾病 的 征兆。
# Designing Sound in SuperCollider/Creaking door
## Fig 32.6: putting it all together

The following re-uses the functions defined further up this page in combination, to create a door which you can push yourself!
Put the mouse over to the left of the screen before you run this code. Then move the mouse to the right and to the left, to control the amount of force on the door.
# Designing Sound in SuperCollider/Insects
## Fig: 50.13 Direct signal implementation of housefly wing

The adjustable parameters in the pd patch can be controlled by the mouse movement: MouseX is controlling the wing-frequency, MouseY is controlling the wing-resonance.
Leave it running while you run the other blocks of code below...

## Fig: 50.14 Buzzing housefly

If the Synth(\buzzingHousefly) was executed before the Synth(\houseflyWing) you'll have to execute the following line to hear the effects of the Synth(\buzzingHousefly). This is because In.ar and Out.ar are used in this example to communicate between both patches, and when working with In.ar it is always necessary to have the Order of execution of synths on the server in mind. (see also Helpfile: Order of execution).
# Designing Sound in SuperCollider/Pedestrians
## Fig 24.4: pedestrian crossing beeps (UK-style)

The LFPulse here is used to provide a sharp-edged on/off for the sound. (LFPulse outputs a low of zero and a high of one, which is handy in this case so we don't need to re-scale it before we can use it as the multiplier.)
Designing Sound in SuperCollider/thiscodeisby
# Designing Sound in SuperCollider/Phone tones
## Fig 25.3: Filter to approximate the transmission medium

Leave it running while you run the other blocks of code below...

## Fig 25.6: Pulse dialling, before DTMF

Designing Sound in SuperCollider/thiscodeisby
# Designing Sound in SuperCollider/Electricity
## Fig 39.3: Hum source

Contains the subpatch shown in fig 39.2.

## Fig 39.8: Hum and sparks

Contains the subpatches shown in fig 39.2, 39.4, 39.5, 39.6 & 39.7. The scope windows show the same information as in the diagnostic graphs of fig 39.4.
# Designing Sound in SuperCollider/Fire
## Fig 34.4: square it

Squaring the noise gives it a more useful dynamic range, with rare loud bursts

## Fig 34.5: more

Add another .squared for even stronger effect on the dynamics, and use a high-pass filter to make the hiss more hissy

## Fig 34.7: many crackles

If we use a proper envelope generator instead of a simple line, we can retrigger it randomly with Dust to give random crackles of a controllable density

## Fig 34.8: more variation

Add more variation by modulating the duration and the filter frequency for each event

## Fig 34.9: woof

Simple attempt at the low "woofing" noise made by the flames themselves

## Fig 34.10: woosh

// another component we could use to build up a flamey sound

## Fig 34.11: shape

Shaping the dynamic range and discarding some of the lower frequencies, allowing a little clipping to give a less static sound.

## Fig 34.13: poly

Let's have four of the above, each filtered differently, for a composite effect
# Designing Sound in SuperCollider/Equivalents for Pure Data Objects

The following list is based on the Pure Data (PD) Object Reference Glossary by Christopher Ariza, which is available at the following URL: http://www.flexatone.net/docs/pdg
The coefficients of the SuperCollider examples are adapted to the behavior of the pure data objects.

## [metro]

Sends a series of bangs at a constant rate in miliseconds.

## [bp~]

Band pass filter. Arguments initialize center frequency and Q.

## [cos~]

The cos~ object outputs the cosine of two pi times its signal input. So -1, 0, 1 and 2 give 1 out, 0.5 gives -1, and so on.
alternatively, use the more common phase modulation and a lookup table:

## [delwrite~]

Delay a signal. Provide a signal as input to add to a delay line. One or more [delread~] or [vd~] objects can read from the delay line created with the [delwrite~] object.
1st argument: name of delay line 2nd argument: length of delay line in msec (= max. delay time)

## [hip~]

One-pole high pass filter.

## [lop~]

One-pole low pass filter.

## [max~]

Return the larger of two signals.

## [min~]

Return the smaller of two signals.

## [noise~]

Uniformly distributed white noise; the output is between -1 and 1.

## [phasor~]

Sawtooth oscillator. Ramps from 0 to 1; can be considered a Sawtooth waveform between 0 and 1.

## [pink~]

Pink noise generator.

## [pow~]

Exponentiate a signal.

## [vd~]

Delay a signal. One or more independent [vd~] objects can read a delay line from one named [delwrite~] object. The delay line must be named as a construction argument. A signal input will set the delay time in milliseconds.

## [vline~]

The vline~ object, like line~, generates linear ramps whose levels and timing are determined by messages you send it. The messages consist of a target value, a time interval (zero if not supplied), and an initial delay (also zero if not supplied.) Ramps may start and stop between audio samples, in which case the output is interpolated accordingly.

## [wrap~]

Remainder modulo 1. The [wrap~] object gives the difference between the input and the largest integer not exceeding it (for positive numbers this is the fractional part).
or use the operator "wrap"
# Designing Sound in SuperCollider/Motors
## Fig 44.5: Motor

Contains the subpatches shown in fig 44.2, 44.3, 44.4 and 44.6.
# General Anatomy/Sensory System

It is the part of nervous system concerned with the receiving of stimulus and sending those signals to the central nervous system (brain and spinal cord) for interpretation and action.

## Components

Sensory system consists of two main parts, peripheral & central.
Peripheral portion of the sensory system consists of:
* receptors: the part which senses the stimuli it can the peripheral terminals of the primary Aferants spatially in pain sensation. The activation of these receptors will discharge the primary Aferant neurons.
* Primary Afferant neurons: They are peripheral Neurons that transmit the signals of stimuli in the form of action potential to the central portions of sensory system.
Central portion of the sensory system consists of:
* nuclei & ganglions of the spinal cord & sensory nuclei & ganglions of cerebral nerves.They amplitude the signals to the upper portions or altered sensations.
* Secondary Aferants. They are neurons in the central nerves system that transmit Aferant signals to the upper regions in the brain.
* The sensory regions of the brain. They process incoming signals and make sensations ultimately.

## Function

* Reception of impulses from environment as well as from within the body
* Conversion of impulses in the form of action potential
* Transmission of action potential through nerves to the central nervous system

## See also

Sensory Systems
# General Anatomy/Urinary System

Urinary System
* Kidney - are bean shaped organ that serves several essential regulatory roles in vertebrates
* Ureter - are tubes made of smooth fibers that propel urine from the kidneys to the urinary bladder
* Bladder : A storage device of human body where urine gets stored
# General Anatomy/Tetralogy of Fallot

Tetralogy of Fallot includes a Large Ventricular Septal Defect (VSD), the aorta overrides left and right ventricles, right ventricular outflow tract is obstructed, and the wall of the right ventricle thickens. More blood shunts through the VSD to the left side as the obstruction impedes the RV outflow, resulting in Cyanosis; Tetralogy of Fallot has four key features. A Ventricular Septal Defect (a hole between the ventricles) and many levels of obstruction from the right ventricle to the lungs (Pulmonary Stenosis) are the most important. Also, the Aorta (major artery from the heart to the body) lies directly over the Ventricular Septal Defect, and the right ventricle develops thickened muscle.”
Adults with Tetralogy of Fallot suffer shortness of breath and can’t tolerate exercise. Brain abscesses, strokes and heart infections can arise as complications. Tetralogy of Fallot patient’s fingers may have "clubbing" which is enlargements at the distal ends. If Tetralogy of Fallot remains uncorrected, most patients die in childhood.
Diagnosis is made with Echocardiography; the VSD can be visualized with Color Doppler, and the diagnosis can be confirmed with Heart Catherterization.
Surgical repair improves survival and helps relieve symptoms. Patients should receive antibiotics before dental work or surgery.
“Even with repair these patients have a poorer survival rate… Patients with repaired tetralogy of Fallot often have atrial fibrillation or flutter, which may cause considerable morbidity.”
Pulmonary regurgitation may develop; it can be tolerated for long periods, but then the right ventricle enlarges and malfunctions, and a replacement pulmonary valve may be needed.
Some patients have recurring obstruction of the outflow tract in the right ventricle, and need repeated surgery. Large residual ventricular septal defects may require repeated surgery in 10 to 20 percent of patients. After repair of tetralogy of Fallot, Right bundle branch block patterns (RBBB) is common, apparently increasing the chances of death. However, sometimes the first surgery is successful.
Survival is better among patients who had the surgery young. “Left and right ventricular failure due to right ventricular overload or left ventricular volume overload is another important cause of late death in older patients.”
Patients who had the surgery as adolescents or adults may have greater difficulty with exercise.

## References

* 1 2 3 4 5 6 7 8 http://www.rjmatthewsmd.com/Definitions/congenital_heart_disease.htm
* 1 2 http://www.americanheart.org/presenter.jhtml?identifier=11071
* ↑ http://circ.ahajournals.org/cgi/content/abstract/circulationaha;54/2/289
# General Astronomy/Active Galactic Nuclei and Quasars

In the 1970s, astronomers discovered an object so bright that it shone with the light of a trillion or more suns. Oddly, this object appeared small and starlike in the images, and became known as a "quasi-stellar radio source," which was shortened to "quasar." Since then many more have been discovered. Quasars also are extremely far away and long ago in time, and apparently represent a very early stage of galaxy evolution.
Other similar objects exists with very energetic cores, although not as energetic as the quasars. These include Seyfert Galaxies, BL Lacerta objects and variations. Such galaxies are said to have "Active Galactic Nuclei" or AGN for short. Interestingly, they are generally closer to us in both space and time than the quasars, and appear to form part of a time evolution sequence for galaxies.
The galaxies nearest the Milky Way (us) are quiescent or quiet.
So to recap, very distant objects such as quasars, which also represent objects very far back in time, are very energetic. Those that are mid-range from us (in both space and time) are less energetic, but more so than the Milky Way. Those that are closest to us (again, in space and time) are quiet.
Evidence suggests that a supermassive black hole (SMBH) forms at the core of most, if not all, galaxies (including quasars). In the early stages of galaxy formation, material continues to fall into the black hole. Although the black hole itself emits no (thermal) radiation, material falling into the black hole emits prodigious amounts of energy. This represents the quasars.
As time goes on, less and less material is available to fall into the SMBH, and correspondingly the energy radiating from the vicinity of the black hole diminishes. This represents the mid-range galaxies with Active Galactic Nuclei.
Eventually, the SMBH becomes quiescent (quiet) when no significant material is available to be "devoured." These represent the Milky Way and nearby galaxies.
# General Astronomy/Apparent Motions of the Planets

Before the common acceptance of the heliocentric model in the mid 1500s, the Earth was believed to be the center of the known universe. Many inherent problems in the geocentric model of the universe led Nicolaus Copernicus to formulate an alternate means by which planets and stars moved. Two such problems are the apparent retrograde motion of various planets, specifically Mars, and the ensuing epicycle theory made to compensate for this issue, as well as the phases of Venus that occur.

## Planetary Motion and Epicycles

Viewing Earth as the center of our universe, many of the planets in our solar system take on a peculiar motion across the night sky. For instance, Mars appears to move in a retrograde fashion from time to time. Since the geocentric model holds that all the planets in our solar system orbit the Earth, this would mean that from time to time Mars reverses its orbital direction only to resume it later. The Greek astronomer, Ptolemy, sought to explain this phenomenon with the use of epicycles - that is, small circular motions that planets orbiting the Earth followed on top of their circular orbit around the Earth. Astronomers from Greek times to the Enlightenment compensated for flaws in the geocentric model by adding extra layers of epicycles, until the system was so complex it became virtually unusable. Copernicus' heliocentric model, placing the Sun at the center with planets going around it rather than around the Earth, rid the universe of many of the epicycles that plagued astronomy at that time.

## Phases of Venus

Another problem with the geocentric model occurred when observing Venus and its relative phases: should Venus and the Sun orbit the Earth, then it would be impossible for Venus to be in the "full" phase, that is complete illumination (similar to a full moon). Thus, the Ptolemaic model predicted only crescent and new phases of Venus. Yet, as Galileo observed, this was clearly not the case; Venus exhibited all phases of the moon, a phenomenon predicted and accounted for by Copernicus' model. Discovered by Galileo, this phenomenon was one of the key factors that would end up supporting the Heliocentric view of the universe.
Note that this is only one of a number of observations made by Galileo that contradicted the ancient beliefs, but this one most directly called into question the idea that planets orbit the Earth.

## References

* Shea, William R. Galileo in Rome: the Rise and Fall of a Troublesome Genius. New York: Oxford UP, USA, 2004.
# General Astronomy/An Accelerating Universe

Space is flat. This is shown by the density of matter, and cosmic background radiation.
The radiation left over from the Big Bang is about 3 Kelvin.
The rate of expansion of the universe is greater in proportion to the distance.

## Other Cosmological Models

Throughout history, astronomers have been seeking models of the universe. The three best known are those by Ptolemy, Newton, and Einstein. They all had an explanation why the universe didn't collapse.
Ptolemy's model had the Earth at the center, surrounded by an "8th Sphere" of stars. The sphere held up the stars, so the universe didn't collapse.
Newton's universe was infinitely large. He postulated a universe where the gravitational force was in balance. In an infinitely large area, there is no center of mass; therefore, the universe could not collapse. Like many of his time, Newton also believed in an infinitely old universe. Given an infinite amount of time, if the universe was going to collapse, it would've done it already.
Flaws with Newton's model were apparent even in his time. Heinrich Olbers wondered: If the universe is infinitely large and infinitely old, why isn't the night sky as bright as the sun? This question became known as Olbers' Paradox. Olbers' proposed solution was that the universe was filled with dust, obscuring some of the starlight. However, this only appeared to solve the problem. Dust absorbs and radiates energy, so that the light being obscured would be transmitted anyway.
Einstein's model for the universe was a constant size. He postulated a repulsive $\lambda$ (lambda) force that counterbalanced gravity and kept everything from collapsing.
Immanuel Kant, a philosopher, proposed a disc-shaped universe.