Miracle-dz/UniFAR-FTUs huggingface dataset:
Molecular studies of Planetary Nebulae

Abstract Circumstellar envelopes (CEs) around evolved stars are an active site for the production of molecules. After evolving through the Asymptotic Giant Branch (AGB), proto-planetary nebula (PPN), to planetary nebula (PN) phases, CEs ultimately merge with the interstellar medium (ISM). The study of molecules in PNe, therefore, is essential to understanding the transition from stellar to interstellar materials. So far, over 20 molecular species have been discovered in PNe. The molecular composition of PNe is rather different from those of AGB and PPNe, suggesting that the molecules synthesized in PN progenitors have been heavily processed by strong ultraviolet radiation from the central star. Intriguingly, fullerenes and complex organic compounds having aromatic and aliphatic structures can be rapidly formed and largely survive during the PPN/PN evolution. The similar molecular compositions in PNe and diffuse clouds as well as the detection of C60 + in the ISM reinforce the view that the mass-loss from PNe can significantly enrich the ISM with molecular species, some of which may be responsible for the diffuse interstellar bands. In this contribution, I briefly summarize some recent observations of molecules in PNe, with emphasis on their implications on circumstellar chemistry.
Formation of Extremely Low-mass White Dwarfs in Double Degenerates

Extremely low-mass white dwarfs (ELM WDs) are helium WDs with a mass less than ∼0.3 M⊙. Most ELM WDs are found in double degenerates (DDs) in the ELM Survey led by Brown and Kilic. These systems are supposed to be significant gravitational-wave sources in the mHz frequency. In this paper, we first analyzed the observational characteristics of ELM WDs and found that there are two distinct groups in the ELM WD mass and orbital period plane, indicating two different formation scenarios of such objects, i.e., a stable Roche lobe overflow channel (RL channel) and common envelope ejection channel (CE channel). We then systematically investigated the formation of ELM WDs in DDs by a combination of detailed binary evolution calculation and binary population synthesis. Our study shows that the majority of ELM WDs with mass less than 0.22 M⊙ are formed from the RL channel. The most common progenitor mass in this way is in the range of 1.15–1.45 M⊙, and the resulting ELM WDs have a peak around 0.18 M⊙ when selection effects are taken into account, consistent with observations. The ELM WDs with a mass larger than 0.22 M⊙ are more likely to be from the CE channel and have a peak of ELM WD mass around 0.25 M⊙, which needs to be confirmed by future observations. By assuming a constant star formation rate of 2 M⊙ yr−1 for a Milky Way–like galaxy, the birth rate and local density are 5 × 10−4 yr−1 and 1500 kpc−3, respectively, for DDs with an ELM WD mass less than 0.25 M⊙.
Dielectric properties of fluorocarbon thin films deposited by radio frequency sputtering of polytetrafluoroethylene

We investigate the dielectric properties of fluorocarbon thin films deposited by radio-frequency magnetron sputtering of polytetrafluroethylene. The dielectric constant and the loss factor are studied as a function of frequency (0.1 Hz-1 MHz, infrared frequencies) and temperature (room temperature to 100 °C). The value of the dielectric constant is 1.8 at optical frequencies, and around 2.3 in the 0.1 Hz–1 MHz range. The background loss factor is around 0.8% in these samples. Two different polarization mechanisms are identified (β and γ relaxations). The γ process dominates the dielectric constant from 0.1 to 1 MHz. In this frequency range the dielectric constant decreases with temperature (about –4% from room temperature to 100 °C). Temperature dependence of the dielectric constant is well described by a simple Debye model (linear variation of the dielectric constant with 1/T). The γ relaxation is tentatively ascribed to C−F bonds (Nμ2=4×10−32 C2 m−1). The β relaxation has a loss peak located at very low.
Glycogen Synthase Kinase 3β: A True Foe in Pancreatic Cancer

Glycogen synthase kinase 3 beta (GSK-3β) is a serine/threonine protein kinase involved in multiple normal and pathological cell functions, including cell signalling and metabolism. GSK-3β is highly expressed in the onset and progression of multiple cancers with strong involvement in the regulation of proliferation, apoptosis, and chemoresistance. Multiple studies showed pro- and anti-cancer roles of GSK-3β creating confusion about the benefit of targeting GSK-3β for treating cancer. In this mini-review, we focus on the role of GSK-3β in pancreatic cancer. We demonstrate that the proposed anti-cancer roles of GSK-3β are not relevant to pancreatic cancer, and we argue why GSK-3β is, indeed, a very promising therapeutic target in pancreatic cancer.
Multiwavelength Polarization of Rotation-powered Pulsars

Polarization measurements provide strong constraints on models for emission from rotation-powered pulsars. We present multiwavelength polarization predictions showing that measurements over a range of frequencies can be particularly important for constraining the emission location, radiation mechanisms, and system geometry. The results assume a generic model for emission from the outer magnetosphere and current sheet in which optical to hard X-ray emission is produced by synchrotron radiation (SR) from electron–positron pairs and γ-ray emission is produced by curvature radiation (CR) or SR from accelerating primary electrons. The magnetic field structure of a force-free magnetosphere is assumed and the phase-resolved and phase-averaged polarization is calculated in the frame of an inertial observer. We find that large position angle (PA) swings and deep depolarization dips occur during the light-curve peaks in all energy bands. For synchrotron emission, the polarization characteristics are strongly dependent on photon emission radius with larger, nearly 180°, PA swings for emission outside the light cylinder (LC) as the line of sight crosses the current sheet. The phase-averaged polarization degree for SR is less that 10% and around 20% for emission starting inside and outside the LC, respectively, while the polarization degree for CR is much larger, up to 40%–60%. Observing a sharp increase in polarization degree and a change in PA at the transition between X-ray and γ-ray spectral components would indicate that CR is the γ-ray emission mechanism.
Dual-Band Dual-Polarized Antenna Using a Simple Radiation Restoration and Decoupling Structure

This letter presents a simple structure dual-band dual-polarized antenna. The higher-band (HB) antenna is located coaxially under the lower-band (LB) one to save the installation space. The blocking effects of the LB antenna seriously deteriorate the HB antenna's radiation patterns. To solve this problem, we first introduced four stacked patches to restore the radiation performance. Unfortunately, using the stacked patches, the isolation between the LB and HB antennas reduces from about 25 to 20 dB. Then, we introduced four C-shaped metal strips as the decoupling structure and the isolation improves from 20 dB to more than 30 dB within a wideband. These stacked patches and metal strips are printed on top and bottom sides of the LB antenna substrate and therefore no extra substrate layer is needed. For demonstration, a prototype of the dual-band antenna operating at 1710–2690 MHz (LB) and 4200–5000 MHz (HB) is implemented. Normal directional radiation patterns are obtained with stable in-band gains of 7.5 and 9.5 dBi. Better than 33 dB measured isolation between the LB and HB antennas is realized.
CKM benchmarks for electron electric dipole moment experiments

All current experiments searching for an electron EDM d_e are performed with atoms and diatomic molecules. Motivated by significant recent progress in searches for an EDM-type signal in diatomic molecules with an uncompensated electron spin, we provide an estimate for the expected signal in the Standard Model due to the CKM phase. We find that the main contribution originates from the effective electron-nucleon operator $\bar{e} i\gamma_5 e \bar{N}N$, induced by a combination of weak and electromagnetic interactions at $O(G_F^2\alpha^2)$, and not by the CKM-induced electron EDM itself. When the resulting atomic P,T-odd mixing is interpreted as an {\it equivalent} electron EDM, this estimate leads to the benchmark $d_e^{equiv}(CKM) \sim 10^{-38}$ ecm.
Uniformly moving non-singular dislocations with elliptical core shape in anisotropic media

To allow for “relativistic”-like core contraction effects, an anisotropic regularization of steadily moving straight dislocations of arbitrary orientation is introduced, with two scale parameters [Formula: see text] and [Formula: see text] along the direction of motion and transverse to it, respectively. The dislocation core shape is an ellipse. When [Formula: see text], the model reduces to the Peierls–Eshelby dislocation, the fields of which are non-differentiable on the slip plane. For finite [Formula: see text] and [Formula: see text], fields are everywhere differentiable. Applying the author’s so-called “causal” Stroh formalism to the model, explicit expressions for the regularized fields in anisotropic elasticity are derived for any velocity. For faster-than-wave velocities, Mach-cone angles are found insensitive to the ratio [Formula: see text], as must be. However, the larger [Formula: see text], the weaker the intensity of the cone branches. An expression is given for the radiative dissipative force opposed to motion. From this expression, it is inferred that the concept of a “radiation-free” intersonic velocity can, when not applicable, be replaced by that of a “least-radiation” velocity.
Relation between 1/ f noise and frequency-independent loss tangent

A new model has been proposed, which relates the noise in semiconductors to the frequency independent loss tangent in dielectrics. It is demonstrated that this model can explain Hooge's empirical 1/f noise relation. The theoretical results are in agreement with experimental results. The model supports the opinion that 1/f noise is caused by mobility fluctuations.
Brane constructions, fractional branes and anti-deSitter domain walls

Compactifications of type IIB string theory on AdS5X5, where X5 is an Einstein space, can have one-fourth or half maximal supersymmetry for certain choices of X5. Some of these theories admit exotic domain walls arising from 5-branes wrapping 2-cycles in X5. We explore the relationship among these domain walls, fractional branes and branes stretched on intervals. World-volume fluxes in the wrapped branes play an important role in the analysis. We draw some parallels between the AdS background with exotic domain walls and = 1 supersymmetric MQCD, and identify other extended objects on the AdS side in the dual brane construction. The process of brane creation is used to give an alternate derivation of the relationship between fractional branes and branes on intervals.
A direct and differential imaging search for sub-stellar companions to ε Indi A

We have carried out a direct and differential imaging search for sub-stellar companions to ϵ Indi A using the adaptive optics system NACO at the ESO VLT. The observations were carried out in September 2004 with NACO/SDI as well as with NACO's S27 camera in the H and K s filters. The SDI data cover an area of ~2.8´´ around ϵ Indi A. No detection was achieved in the inner neighbourhood down to 53 M J (5 σ confidence level) at a separation ≥ 0.4´´(1.45 AU) and down to 21 M J for separations ≥ 1.3´´ (4.7 AU). To cover a wider field of view, observations with the S27 camera and a coronagraphic mask were obtained. We detected a faint source at a separation of (7.3 ± 0.1)´´and a position angle of $(302.9\,\pm\,0.8)^{\circ}$. The photometry for the candidate companion yields m H = (16.45 ± 0.04) mag and $ m_{K_{\rm s}}$ = (15.41 ± 0.06) mag, respectively. Those magnitudes and the resulting color ($H-K_{\rm s}$) = (1.04 ± 0.07) mag fit best to a spectral type of L5 – L9.5 if it is bound. Observations done with HST/NICMOS by M. Endl have shown the source to be a background object.
Near-hexagonal close-packed optical fiber bundle for parallel optical interconnection

In conventionally 2-dimensional (2-D) parallel optical interconnection (POI), optical fibers must be accurately aligned to 2-D light sources and detectors using precisely fabricated hole-plate or stacked V-grooves. For polymer optical fibers with large diameter, the whole dimension of the bundle may be too huge to connect ICs if they are positioned using V-grooves or hole-plate. We propose a near hexagonal close packed optical fiber bundle (NHCP-OFB) to closely pack the fibers into a 2-D near hexagonal lattice with high positioning accuracy. Due to the fluctuation of the diameter of the commercial optical fibers, they cannot be packed into perfect hexagonal close packed (HCP) bundle. The proposed NHCP-OFB slightly stretches the perfect (HCP) bundle in one dimension and still have all fibers packed tightly with high packing fraction. The position of fibers in NHCP-OFB is very important when aligned to 2-D light sources and detectors. This paper analytically analysis the positioning offset of fibers in NHCP-OFB. The possibility distribution of positioning offset is related to variance of fiber diameter and stretched length of NHCP-OFB. Experiment samples of NHCP-OFB have been made using polymer optical fiber showing that fibers can be precisely positioned.
Bayesian priors and nuisance parameters

Bayesian techniques are widely used to obtain spectral functions from correlators. We suggest a technique to rid the results of nuisance parameters, ie, parameters which are needed for the regularization but cannot be determined from data. We give examples where the method works, including a pion mass extraction with two flavours of staggered quarks at a lattice spacing of about 0.07 fm. We also give an example where the method does not work.
Mountain Climbing, Ladder Moving, and the Ring-width of a Polygon

Keywords: polygon ; piecewise linear ; ring-width of polygons Note: Professor Pach's number: [051] Reference DCG-ARTICLE-1989-003doi:10.2307/2323971 Record created on 2008-11-14, modified on 2017-05-12
Transforming Student Learning with Classroom Communication Systems

Since 1993, the University of Massachusetts Physics Education Research Group (UMPERG) has developed curriculum and pedagogic techniques for use with classroom communication systems (CCSs) and has researched the effectiveness of CCS-based teaching. This bulletin describes how CCSs can influence "interactive pedagogy" and fundamentally transform the learning process. It includes advice drawn from lessons learned through a decade of experience.
Fidelity susceptibility in one-dimensional disordered lattice models

We investigate quantum phase transitions in one-dimensional quantum disordered lattice models, the Anderson model and the Aubry-Andr\'{e} model, from the fidelity susceptibility approach. First, we find that the fidelity susceptibility and the generalized adiabatic susceptibility are maximum at the quantum critical points of the disordered models, through which one can locate the quantum critical point in disordered lattice models. Second, finite-size scaling analysis of the fidelity susceptibility and of the generalized adiabatic susceptibility show that the correlation length critical exponent and the dynamical critical exponent at the quantum critical point of the one-dimensional Anderson model are respectively 2/3 and 2 and of the Aubry-Andr\'{e} model are respectively 1 and 2.375. Thus the quantum phase transitions in the Anderson model and in the Aubry-Andr\'{e} model are of different universality classes. Because the fidelity susceptibility and the generalized adiabatic susceptibility are directly connected to the dynamical structure factor which are experimentally accessible in the linear response regime, the fidelity susceptibility in quantum disordered systems may be observed experimentally in near future.
IRAS Detections of Metal‐poor Red Giants

A number of relatively bright metal‐poor red giants from the HD and BD catalogs are found to have been detected by the IRAS satellite. Data for these stars have been retrieved from the IRAS Point Source Catalog (PSC) and/or the Faint Source Catalog (FSC). The majority of metal‐poor giants in these samples fall along relatively well‐defined sequences in plots of V - [12] versus B - V and V - I; for these stars, the 12 μm flux detected is presumed to arise from the photosphere. Only a subset of stars detected at 12 μm were detected at 25 μm; these are displayed in a plot of [12] - [25] versus V - [12]. There are a small number of giants that exhibit notable 12 and/or 25 μm excesses relative to the mean sequences defined by the bulk of the sample. Those stars with the most unambiguous evidence for infrared excesses are variable stars, either long‐period or semiregular variables or RV Tauri stars. As such, those stars exhibiting infrared excesses in the metal‐poor giant sample are likely in the asymptotic giant branch (AGB) or post‐AGB phase of evolution. There is no clear evidence for nonvariable first‐ascent red giants having been detected among the infrared‐excess stars. In fact, some metal‐poor red giants known to exhibit outflows in their chromospheres do not show infrared excesses. A Population II star ascending the red giant branch for the first time appears to have too low a mass‐loss rate to be recognizable as an infrared‐excess star in the IRAS PSC or FSC.
Screening and degenerate kinetic self-acceleration from the nonlinear freedom of reconstructed Horndeski theories

We have previously presented a reconstruction of Horndeski scalar-tensor theories from linear cosmological observables. It includes free nonlinear terms which can be added onto the reconstructed covariant theory without affecting the background and linear dynamics. After discussing the uniqueness of these correction terms, we apply this nonlinear freedom to a range of different applications. First we demonstrate how the correction terms can be configured to endow the reconstructed models with screening mechanisms such as the chameleon, k-mouflage and Vainshtein effects. A further implication is the existence of classes of Horndeski models that are degenerate with standard cosmology to an arbitrary level in the cosmological perturbations. Particularly interesting examples are kinetically self-accelerating models that mimic the dynamics of the cosmological constant to an arbitrary degree in perturbations. Finally, we develop the reconstruction method further to the level of higher-order effective field theory, which under the restriction to a luminal propagation speed of gravitational waves introduces two new free functions per order. These functions determine the corresponding correction terms in the linearly reconstructed action at the same order. Our results enable the connection of linear cosmological constraints on generalised modifications of gravity and dark energy with the nonlinear regime and astrophysical probes for a more global interpretation of the wealth of forthcoming cosmological survey data.
Stationary axisymmetric exteriors for perturbations of isolated bodies in general relativity, to second order

Perturbed stationary axisymmetric isolated bodies, e.g. stars, represented by a matter-filled interior and an asymptotically flat vacuum exterior joined at a surface where the Darmois matching conditions are satisfied, are considered. The initial state is assumed to be static. The perturbations of the matching conditions are derived and used as boundary conditions for the perturbed Ernst equations in the exterior region. The perturbations are calculated to second order. The boundary conditions are overdetermined: necessary and sufficient conditions for their compatibility are derived. The special case of perturbations of spherical bodies is given in detail.
Limits to radiative acceleration calculations: lithium and iron

The accuracy with which it is possible to calculate theoretically the positions of energy levels and the low density (in frequency) of the grid on which opacity sampling is calculated both limit the accuracy with which the effect of blends can be determined. For species such as Fe for which a large number of transitions are involved in calculations, this leads to a small effect since, statistically, cancellations occur. However the effect can be large for an element such as Li with only a few transitions contributing to its radiative acceleration, g rad (Li), at any given stellar radius. In particular, the Fe lines are shown to modify g rad (Li) in and below the Fe convection zone but the modification depends on Fe level positions. This is analyzed quantitatively here using the OPAL data base. The g rad (Li) are found to be uncertain by a factor of 2 in Pop I stars but of 1.03 in Pop II stars.
Gravitational Lensing in QSO 1208+10 from the Proximity Effect in Its Lyα Forest

The quasar Q1208+1011 (z=3.8) is the second-highest redshift double quasar ever detected. Several indications point toward it being a gravitationally lensed system, although a definitive proof is still lacking. We present new evidence of its lensed nature, based on the weakness of the "proximity effect" measured in the high-resolution Lyman absorption spectrum of the QSO. A luminosity amplification as large as 22 has been derived from this analysis. Indications in the redshift of the lensing galaxy can be obtained from an analysis of the intervening heavy-element absorption systems discovered in the QSO high-resolution spectrum. On statistical and dynamical grounds, a Mg II system present at z=1.13 appears to be the most likely candidate for the lensing galaxy. We compare the observed parameters with a simple isothermal model for the lens to derive the properties of the lensing galaxy. The resulting magnification factor is smaller, although marginally consistent with that derived by analysis of the proximity effect.
MEMs-based speckle spectrometer

We describe a new concept for a MEMS-based active spatial filter for astronomical spectroscopy. The goal of this device is to allow the use of a diffraction-limited spectrometer on a seeing limited observation at improved throughput over a comparable seeing-limited spectrometer, thus reducing the size and cost of the spectrometer by a factor proportional to r0/D (For the case of a 10 meter telescope this size reduction will be approximately a factor of 25 to 50). We use a fiber-based integral field unit (IFU) that incorporates an active MEMS mirror array to feed an astronomical spectrograph. A fast camera is used in parallel to sense speckle images at a spatial resolution of λ/D and at a temporal frequency greater than that of atmospheric fluctuations. The MEMS mirror-array is used as an active shutter to feed speckle images above a preset intensity threshold to the spectrometer, thereby increasing the signal-to-noise ratio (SNR) of the spectrogram. Preliminary calculations suggests an SNR improvement of a factor of about 1.4. Computer simulations have shown an SNR improvement of 1.1, but have not yet fully explored the parameter space.
Optimal resources for topological two-dimensional stabilizer codes : Comparative study

We study the resources needed to construct topological two-dimensional stabilizer codes as a way to estimate in part their efficiency, and this leads us to perform a comparative study of surface codes and color codes. This study clarifies the similarities and differences between these two types of stabilizer code. We compute the topological error-correcting rate C:=n/d{sup 2} for surface codes C{sub s} and color codes C{sub c} in several instances. On the torus, typical values are C{sub s}=2 and C{sub c}=3/2, but we find that the optimal values are C{sub s}=1 and C{sub c}=9/8. For planar codes, a typical value is C{sub s}=2, while we find that the optimal values are C{sub s}=1 and C{sub c}=3/4. In general, a color code encodes twice as many logical qubits as does a surface code.