Miracle-dz/UniFAR-FTUs huggingface dataset:
The First Mid-Infrared Detection of a Source Coincident with Sagittarius A*

We present the first mid-infrared detection of a source coincident with the black hole candidate Sgr A* in a deep image of the inner parsec of the Galaxy. These data were obtained with SpectroCam-10 at the 200 inch (5.08 m) Hale telescope. The source was detected at 8.7 μm on two separate occasions using different observing techniques. The spatial resolution is ~0. ″7 and the noise level is 1.6 mJy beam-1 in the combined mosaic near Sgr A*. A source at Sgr A* is weakly apparent in the raw data but is difficult to identify due to strong diffuse dust emission with a mean flux density of 500 mJy arcsec-2. Several deconvolution techniques were applied to achieve the diffraction limit of 0. ″44, all of which revealed a peak on a narrow NW-SE ridge of emission. The peak is coincident with Sgr A* within the ±0. ″3 uncertainty in locating Sgr A* relative to IRS 7. We estimate the flux density of the Sgr A* source above the ridge to be 25 ± 5 mJy. The extinction-corrected 8.7 μm flux density of ~100 mJy is significantly greater than what is predicted by dustless accretion disk models. The excess emission is best explained by warm dust which may be associated with Sgr A* or heated by local stellar sources.
Effect of boundary reaction on solute dispersion in pulsatile flow through a tube

This paper examines the streamwise dispersion of passive contaminant molecules released in a time-dependent laminar flow through a tube in the presence of boundary absorption or a catalytic wall reaction, which causes a depletion of contaminant in the flow. A finite-difference implicit scheme has been used to solve the unsteady convective–diffusion equation for all time. Here it is shown how the mixing of the cross-sectionally integrated concentration of contaminant molecules is influenced by the frequency of pressure pulsation and the heterogeneous reaction at the boundary. The behaviour of the dispersion coefficient due to the shear effects of steady, oscillatory, and the combined action of steady and periodic currents have been examined separately. The comparison reveals that for all cases the dispersion coefficient asymptotically reaches a stationary state after a certain time and it decreases with the absorption parameter. The increased wall absorption causes negatively skewed deviations from Gaussianity.
Effects of patterned, stressed SiN overlayers on Si solid phase epitaxy

Striking nonuniformities are observed in the solid phase epitaxy (SPE) of blanket amorphized Si layers recrystallized in the presence of stress distributions induced by a patterned SiN overlayer. Measurements conducted for a range of SiN feature sizes and intrinsic stress values allowed us to isolate the effects of stress on the crystallization front. It is concluded that SiN-induced variations in SPE rates arise both from line-edge stresses, which scale with feature stress and increase SPE rates where the hydrostatic stress is compressive, and a SiN body effect, which suppresses SPE rates under the SiN features, independent of SiN stress state.
MAGNETIC-RECONNECTION GENERATED SHOCK WAVES AS A DRIVER OF SOLAR SURGES

We found that a surge consists of multiple shock features. In our high-spatiotemporal spectroscopic observation of the surge, each shock is identified with the sudden appearance of an absorption feature at the blue wings of the Ca ii 8542 Å line and Hα line that gradually shifts to the red wings. The shock features overlap with one another with the time interval of 110 s, which is much shorter than the duration of each shock feature, 300–400 s. This finding suggests that the multiple shocks might not have originated from a train of sinusoidal waves generated by oscillations and flows in the photosphere. As we found the signature of the magnetic flux cancelations at the base of the surge, we conclude that the multiple shock waves in charge of the surge were generated by the magnetic reconnection that occurred in the low atmosphere in association with the flux cancelation.
Anomalous Behavior in Electrical Transport Properties in Single-Crystal Gd $_{5}$ Si $_{1.8}$ Ge $_{2.2}$ and Polycrystalline Gd $_{5}$ Si $_{2.09}$ Ge $_{1.91}$

Gd5(SixGe1-x)4 exhibits anomalous behavior in resistivity measurement close to its first-order phase transition temperature. In this paper, we present a series of resistivity as a function of temperature measurements indicating an irreversible change in the resistivity. The resistivity of the sample increased every time the sample was passed through first-order phase transition for both single-crystal Gd5Si1.8Ge2.2(x=0.45) and polycrystalline Gd5 Si2.09 Ge1.91(x=0.522). Magnetic hysteresis loops were also plotted for the single-crystal Gd5 Si1.8 Ge2.2 at 220 K. The hysteresis loops were measured several times at 220 K, cycling the temperature between 220 and 300 K between each measurement. The coercivity of the sample increased irreversibly when the sample was passed through the first-order phase transition. The increase in the coercivity was 20 Oe for the fourth and fifth thermal cycles and then it remained constant up to 15 thermal cycles.
Mitigating Catastrophic Forgetting in Spiking Neural Networks through Threshold Modulation

Artificial Neural Networks (ANNs) trained with Backpropagation and Stochastic Gradient Descent (SGD) suffer from the problem of Catastrophic Forgetting; when learning tasks sequentially, the ANN tends to abruptly forget previous knowledge upon being trained on a new task. On the other hand, biological neural networks do not suffer from this problem. Spiking Neural Networks (SNNs) are a class of Neural Networks that are closer to biological networks than ANNs and their intrinsic properties inspired from biology could alleviate the problem of Catastrophic Forgetting. In this paper, we investigate if the firing threshold mechanism of SNNs can be used to gate the activity of the network in order to reduce catastrophic forgetting. To this end, we evolve a Neuromodulatory Network that adapts the thresholds of an SNN depending on the spiking activity of the previous layer. Our experiments on different datasets show that the neurmodulated SNN can mitigate forgetting significantly with respect to a fixed threshold SNN. We also show that the evolved Neuromodulatory Network can generalize to multiple new scenarios and analyze its behavior.
Reducing Response Time in Fork-Join Systems under Heavy Traffic Via Imbalance Control

We consider the problem of reducing the response time of fork-join systems by maintaining the workload balanced among the processing stations. The general problem of modeling and finding an optimal policy that reduces imbalance is quite difficult. In order to circumvent this difficulty, the heavy traffic approach is taken, and the system dynamics are approximated by a reflected diffusion process. This way, the problem of finding an optimal balancing policy that reduces workload imbalance is set as a stochastic optimal control problem, for which numerical methods are available. Some numerical experiments are presented, where the control problem is solved numerically and applied to a simulation. The results indicate that the response time of the controlled system is reduced significantly using the devised control.
A Consistency Result for a Discrete-Velocity Model of the Boltzmann Equation

In this paper, we study the link between a certain class of discrete-velocity models (DVMs) and the Boltzmann equation. Those models possess an infinite number of velocities laying on a regular grid of step h in R3. Our aim is to prove that it is possible to construct models consistent with the Boltzmann equation, i.e., such that the discrete collision term can be seen as an approximation of the collision integral of the Boltzmann equation.
Dynamic Latent Trait Models for Multidimensional Longitudinal Data

This article presents a new approach for analysis of multidimensional longitudinal data, motivated by studies using an item response battery to measure traits of an individual repeatedly over time. A general modeling framework is proposed that allows mixtures of count, categorical, and continuous response variables. Each response is related to age-specific latent traits through a generalized linear model that accommodates item-specific measurement errors. A transition model allows the latent traits at a given age to depend on observed predictors and on previous latent traits for that individual. Following a Bayesian approach to inference, a Markov chain Monte Carlo algorithm is proposed for posterior computation. The methods are applied to data from a neurotoxicity study of the pesticide methoxychlor, and evidence of a dose-dependent increase in motor activity is presented.
Examples of nonpolar limit spaces

In this paper we give an example showing that a limit space of manifolds with positive Ricci curvature can be nonpolar. Recall that a polar space is a space all of whose tangent cones have a pole at the origin. Polar limit spaces have many regularity properties. For instance, J. Cheeger and T. Colding have proven that the Hausdorff dimension of a polar limit space is an integer.
Frequency chirp under current modulaton in InGaAsP injection lasers

We have measured the frequency chirp in gain‐guided, weakly index‐guided, and strongly index‐guided InGaAsP lasers under direct‐current modulation. The measured chirp width is largest for gain‐guided and smallest for weakly index‐guided ridge waveguide lasers. The chirp width for 1.5‐μm InGaAsP lasers is about a factor of 2 larger than that for 1.3‐μm InGaAsP lasers of the same structure. The frequency chirping results from a modulaton of the carrier density which modulates the effective refractive index of the guided mode. The frequency chirping can introduce a limitation on the performance of single‐frequency injection laser sources for high bit‐rate digital transmission in fiber communication systems at 1.55 μm.
Superconductivity near the normal state in a half-plane under the action of a perpendicular electric current and an induced magnetic field

We consider the linearization of the time-dependent Ginzburg-Landau system near the normal state. We assume that a constant magnetic field and an electric current are applied through the sample, which captures half of the plane, inducing thereby, a linearly varying magnetic field. In the limit of small normal conductivity we prove that if the electric current is lower than some critical value, the normal state loses its stability. For currents stronger than this critical value, the normal state is stable. To obtain this stability result we analyze both the spectrum and the pseudo-spectrum of the linearized operator. The critical current tends, in this small conductivity limit, to another critical current which had been obtained for a reduced model which neglects magnetic field effects.
Dielectric relaxations of yttrium iron garnet ceramics over a broad temperature range

Dielectric response of Y3Fe5O12 ceramics was investigated over broad temperature and frequency ranges. Three dielectric relaxations were identified in the temperature range from 125to620K. A Debye-type dielectric relaxation at low temperatures (125–320K) with an activation energy of 0.29eV is shown to originate from the carrier hopping process between Fe2+ and Fe3+. In a higher temperature range (320–620K), a low frequency (f≦10kHz) dielectric relaxation with an activation energy of 0.84eV most likely arises from the inhomogeneous structure, such as grain boundaries. Another dielectric relaxation in a wider frequency range has a similar activation energy with conduction (Ea=1.00eV) suggests that it can be attributed to the conduction.
Parity Dimension for Graphs - A Linear Algebraic Approach

For a graph G with closed neighborhood matrix N , the parity dimension of G , denoted PD( G ), is the dimension of the null space of N over the field ${\cal Z}_2$ . Equivalently, the number of vertex sets S in G with the property that S dominates each vertex an even number of times is 2 k for some value of k , and PD( G ) = k . Using primarily linear algebraic techniques, we investigate the parity dimension of graphs.
Molecular clouds and cloud cores in the inner Galaxy

A compilation of CO emission regions and their measured parameters is presented which represents a nearly complete accounting of the molecular clouds in the first quadrant of the Galaxy. Emission regions associated with radio H II regions have systematically brighter CO peaks that are a factor of two to three times larger and have twice the mean velocity dispersion as the general cloud population. Both the H II region clouds and the hot core regions have a Galactic distribution characteristic of a spiral arm population, whereas the colder clouds are much less confined in Galactic azimuthal angle. Virial masses are obtained for the large sample of clouds with assigned kinematic distances. The mean H2 density for a GMC of diameter 40 pc is 180/cm. For these clouds, a linear relationship is found between the H2 column density and the integrated CO emission. The variation in the Z-dispersion of clouds as a function of cloud mass suggests that more massive GMCs have smaller random velocities. 22 references.
Magnetophotoluminescence of biaxially compressed InAsSb quantum wells

Heterostructures with biaxially compressed InAsSb are being considered as active regions for midwave infrared diode lasers. Quantum wells of biaxially compressed InAs1−xSbx (x≊0.09) in unstrained InAs were characterized using magnetophotoluminescence. The quantum size shift of the photoluminescence for a series of quantum wells produced an estimate of the conduction band offset. In magnetic field studies, the holes in the strained quantum wells exhibited a decrease in effective mass, approaching that of the electrons. A type I band offset was observed for these InAsSb/InAs heterostructures. Throughout this study, magnetoexcitonic behavior is observed; our analysis indicates that the exciton binding energy increases with quantum confinement.
Relationship between density peaking, particle thermodiffusion, Ohmic confinement, and microinstabilities in ASDEX Upgrade L-mode plasmas

New experimental results obtained in ASDEX Upgrade [O. Gruber, H. -S. Bosch, S. Gunter et al., Nucl. Fusion 39, 1321 (1999)] plasmas in low confinement mode with central electron cyclotron heating are presented in which transitions in both the particle and electron heat transport properties have been observed. A comprehensive albeit qualitative explanation for both the transport channels is provided in the framework of the theory of ion temperature gradient and trapped electron mode microinstabilities. The different transport behaviors are related to the dominant instability at play and to the collisionality regime. In particular, central electron heating induces a flattening of the density profile when the dominant instability is a trapped electron mode, and density peaking is observed to increase with decreasing collisionality.
Frequency division using a micromechanical resonance cascade

A coupled micromechanical resonator array demonstrates a mechanical realization of multi-stage frequency division. The mechanical structure consists of a set of N sequentially perpendicular microbeams that are connected by relatively weak elastic elements such that the system vibration modes are localized to individual microbeams and have natural frequencies with ratios close to 1:2:⋯:2N. Conservative (passive) nonlinear inter-modal coupling provides the required energy transfer between modes and is achieved by finite deformation kinematics. When the highest frequency beam is excited, this arrangement promotes a cascade of subharmonic resonances that achieve frequency division of 2j at microbeam j for j = 1, …, N. Results are shown for a capacitively driven three-stage divider in which an input signal of 824 kHz is passively divided through three modal stages, producing signals at 412 kHz, 206 kHz, and 103 kHz. The system modes are characterized and used to delineate the range of AC input voltages and fre.
Équations de Fermat de type (5, 5, p )

Soient p un nombre premier ≥ 7 et d un entier naturel sans puissances cinquiemes. Nous mettons en œuvre les differentes methodes modulaires connues pour l'etude de l'equation diophantienne x 5 +y 5 = dz p . Nous montrons en particulier qu'elle n'admet aucune solution propre et non triviale pour p ≥ 7 ou pour une infinite de nombres premiers, dans certains cas ou d est de la forme 2 α . 3β. 5γ. Pour d = 3, on enonce un critere permettant de verifier, notamment, que tel est le cas lorsque p est ≤ 10 6 . Let p be a prime number ≥ 7 and d be a positive integer fifth power free. We use the known modular methods for the study of the diophantine equation x 5 +y 5 = dz p . We prove that this equation has no non trivial proper solution for p ≥ 7 or for infinitely many prime numbers, in some cases where d is of the form 2 α . 3β. 5γ. For d = 3, we give a criterion which allows us to verify that this holds if p is less than 10 6 .
Device model investigation of single layer organic light emitting diodes

We present calculations of single layer organic light emitting diode (LED) characteristics using a device model which includes charge injection, transport, recombination, and space charge effects in the organic material. Contact limited and ohmic contacts, high and low carrier mobilities, and device thicknesses from 5 to 200 nm are considered. The scaling of device current with applied voltage bias and organic film thickness is described for contact limited and ohmic contacts. Calculated device current, light output, and quantum and power efficiency are presented for representative cases of material and device parameters. These results are interpreted using the calculated spatial variation of the electric field, charge density, and recombination rate density in the devices. We find that efficient single layer organic LEDs are possible for a wide range of organic material and contact parameters.
$p$-Valent classes related to functions of bounded boundary rotation

Let f(z) = z q + Xn=Q + i fl «z n ^ e analytic in U:{z : |z| < 1}. We say / belongs to the class V kK (p, q) (k ^ 2, |X| < TT/2, p=q) if/has (p — 1) critical points in U and for r sufficiently close iriT( ,+ T$? )>i lim ^ fcp7T cos X. For k = 2, we have the class of p-valent functions/for which zf ' is X-spiral-like in U. We obtain representation theorems for these classes which lead to distortion and rotation theorems. For V kk (p, p) bounds for |fl p+1 | and |a p+2 l are determined. These results are sharp. 30A32.
Some new methods for the numerical integration of ordinary differential equations

The choice of a numerical method for the solution of ordinary differential equations depends on the associated boundary conditions. When all the boundary conditions are specified at one end of the range of integration, one of the well-known step-by-step methods will generally be used, while the method of relaxation is reserved for the case in which boundary conditions are specified at more than one point (1). In the latter, simple but inaccurate finite-difference formulae are used to provide a first approximation to the required solution; this approximation is then used to give an estimate of the errors involved in the use of the inaccurate formulae, and successive corrections are obtained until the full, accurate finite-difference equations are satisfied (1). The same principle is followed in this paper with regard to step-by-step methods, the main difference being the way in which approximate solutions are obtained. In relaxation methods simultaneous equations are solved, while in the use of the step-by-step methods suggested here successive pivotal values are built up by the use of recurrence relations. All the methods of this paper follow this principle, differing only in the method of obtaining a recurrence relation, and consequently in the form of the correction terms.
Low‐order models, initialization, and the slow manifold

A nine equation low-order model of the shallow water equations is used as a testbed to compare several initialization strategies and to find points satisfying conditions of “slowness. ” Several methods are explored to initialize the low order model: (1) Lorenz's method of successively zeroing tendencies; (2) minimization of the sum of the squares of the tendencies; (3) use of a balance condition. We find that the balance condition produces the smoothest solution on a consistent basis. In addition, Lorenz initialization, the Newton-Kantorovich Theorem, and the Nested Interval Property are used to compute points devoid of gravity waves to order N for low values of the forcing (F1 ≤ 0.1). Several of these points are calculated.
Toroidally localized and nonlocalized ballooning instabilities in a stellarator

It is shown that the coexistence of toroidally nonlocalized ideal-hydromagnetic ballooning instabilities, with a quasidiscrete spectrum, and toroidally localized ballooning instabilities with a broad continuous spectrum, as predicted by Dewar and Glasser [Phys. Fluids 26, 3038 (1983)] can be realized in a Mercier-unstable equilibrium case modeling the Large Helical Device (LHD) [A. Iiyoshi et al., Fusion Technol. 17, 148 (1990)] with a broad pressure profile. The quasidiscrete, interchange branch corresponds to extended modes that can be understood on the basis of a ripple-averaged ballooning equation, whereas the broad-continuum, ballooning branch corresponds to modes localized along a flux tube. The physical origin of the two branches is discussed.
Flexural wave band gaps in locally resonant thin plates with periodically attached spring–mass resonators

The authors study the propagation of flexural waves in a locally resonant (LR) thin plate made of a two-dimensional periodic array of spring–mass resonators attached on a thin homogeneous plate. The well-known plane wave expansion method is extended to deal with such a plate system with a periodic array of lumped resonant elements. Explicit matrix formulations are developed for the calculation of complex band structures, in which the imaginary parts of Bloch wave vectors are displayed to quantify the wave attenuation performance of band gaps. It is found that resonance-type and Bragg-type band gaps coexist in the LR plate, and the bandwidth of these gaps can be dramatically affected by the resonant frequency of local resonators. In particular, a super-wide pseudo-directional gap can be formed by a combination of the resonance gap and Bragg gap; inside such a pseudo-gap, only a very narrow pass band exists. An explicit formula is further developed to facilitate the design of such a pseudo-gap. Finally, vibration transmission in finite LR plates is calculated using the finite element method. Vibration transmission gaps are observed, and the results are in good agreement with the band gap properties predicted by the complex band structures.
Dynamical x‐ray diffraction from nonuniform crystalline films: Application to x‐ray rocking curve analysis

A dynamical model for the general case of Bragg x-ray diffraction from arbitrarily thick nonuniform crystalline films is presented. The model incorporates depth-dependent strain and a spherically symmetric Gaussian distribution of randomly displaced atoms and can be applied to the rocking curve analysis of ion-damaged single crystals and strained layer superlattices. The analysis of x-ray rocking curves using this model provides detailed strain and damage depth distributions for ion-implanted or MeV-ion-bombarded crystals and layer thickness, and lattice strain distributions for epitaxial layers and superlattices. The computation time using the dynamical model is comparable to that using a kinematical model. We also present detailed strain and damage depth distributions in MeV-ion-bombarded GaAs(100) crystals. The perpendicular strain at the sample surface, measured as a function of ion-beam dose (D), nuclear stopping power (Sn), and electronic stopping power (Se) is shown to vary according to (1–kSe)DSn and saturate at high doses.