Miracle-dz/UniFAR-FTUs huggingface dataset:
Kink scattering in hyperbolic models

In this work, we study kink–antikink and antikink–kink collisions in hyperbolic models of fourth and sixth orders. We compared the patterns of scattering with known results from polynomial models of the same order. The hyperbolic models considered here tend to the polynomial [Formula: see text] and [Formula: see text] models in the limit of small values of the scalar field. We show that kinks and antikinks that interact hyperbolically with the fourth order differ sensibly from those governed by the polynomial [Formula: see text] model. The increasing of the order of interaction to the sixth order shows that the hyperbolic and polynomial models give intricate structures of scattering that differ only slightly. The dependence on the order of interaction is related to some characteristics of the models such as the potential of perturbations and the number of vibrational modes.
Testing for Shock-heated X-Ray Gas around Compact Steep Spectrum Radio Galaxies

We present Chandra and XMM-Newton X-ray, Very Large Array (VLA) radio, and optical observations of three candidate compact steep spectrum (CSS) radio galaxies. CSS sources are of a galactic scale and are presumably driving a shock through the interstellar medium (ISM) of their host galaxy. B3 1445+410 is a low-excitation emission line CSS radio galaxy with possibly a hybrid Fanaroff–Riley FRI/II (or fat double) radio morphology. The Chandra observations reveal a point-like source that is well fit with a power law consistent with the emission from a Doppler boosted core. 3C 268.3 is a CSS broad-line radio galaxy (BLRG) whose Chandra data are consistent spatially with a point source centered on the nucleus and spectrally with a double power-law model. PKS B1017–325 is a low-excitation emission line radio galaxy with a bent double radio morphology. While from our new spectroscopic redshift, PKS B1017−325 falls outside the formal definition of a CSS, the XMM-Newton observations are consistent with ISM emission with either a contribution from hot shocked gas or non-thermal jet emission. We compile selected radio and X-ray properties of the nine bona fide CSS radio galaxies with X-ray detections so far. We find that two out of the nine show X-ray spectroscopic evidence for hot shocked gas. We note that the counts in the sources are low and that the properties of the two sources with evidence for hot shocked gas are typical of the other CSS radio galaxies. We suggest that hot shocked gas may be typical of CSS radio galaxies due to their propagation through their host galaxies.
Maximizing a Family of Optimal Statistics over a Nuisance Parameter with Applications to Genetic Data Analysis

In this article, a simple algorithm is used to maximize a family of optimal statistics for hypothesis testing with a nuisance parameter not defined under the null hypothesis. This arises from genetic linkage and association studies and other hypothesis testing problems. The maximum of optimal statistics over the nuisance parameter space can be used as a robust test in this situation. Here, we use the maximum and minimum statistics to examine the sensitivity of testing results with respect to the unknown nuisance parameter. Examples from genetic linkage analysis using affected sub pairs and a candidate-gene association study in case-parents trio design are studied.
Dynamical Cusp Regeneration

After being destroyed by a binary supermassive black hole, a stellar density cusp can regrow at the center of a galaxy via energy exchange between stars moving in the gravitational field of the single, coalesced hole. We illustrate this process via high-accuracy N-body simulations. Regeneration requires roughly one relaxation time, and the new cusp extends to a distance of roughly one-fifth the black hole's influence radius, with density ρ ~ r-7/4; the mass in the cusp is of the order of 10% of the mass of the black hole. The growth of the cusp is preceded by a stage in which the stellar velocity dispersion evolves toward isotropy and away from the tangentially anisotropic state induced by the binary. We show that density profiles similar to those observed at the center of the Milky Way and M32 can regenerate themselves in several Gyr following the infall of a second black hole; the presence of density cusps at the centers of these galaxies can therefore not be used to infer that no merger has occurred. We argue that ρ ~ r-7/4 density cusps are ubiquitous in stellar spheroids fainter than MV ≈ -18.5 that contain supermassive black holes, but the cusps have not been detected outside of the Local Group, since their angular sizes are less than ~0. ″1. We show that the presence of a cusp implies a lower limit of ~10-4 yr-1 on the rate of stellar tidal disruptions and discuss the consequences of the cusps for gravitational lensing and the distribution of dark matter on subparsec scales.
A linear transformation model for multivariate interval‐censored failure time data

This paper discusses multivariate interval‐censored failure time data observed when several correlated survival times of interest exist and only interval censoring is available for each survival time. Such data occur in many fields, for instance, studies of the development of physical symptoms or diseases in several organ systems. A marginal inference approach was used to create a linear transformation model and applied to bivariate interval‐censored data arising from a diabetic retinopathy study and an AIDS study. The results of simulation studies that were conducted to evaluate the performance of the presented approach suggest that it performs well. The Canadian Journal of Statistics 41: 275–290; 2013 © 2013 Statistical Society of Canada
Dynamical mean-field theory of strongly correlated fermion systems and the limit of infinite dimensions

We review the dynamical mean-field theory of strongly correlated electron systems which is based on a mapping of lattice models onto quantum impurity models subject to a self-consistency condition. This mapping is exact for models of correlated electrons in the limit of large lattice coordination (or infinite spatial dimensions). It extends the standard mean-field construction from classical statistical mechanics to quantum problems. We discuss the physical ideas underlying this theory and its mathematical derivation. Various analytic and numerical techniques that have been developed recently in order to analyze and solve the dynamical mean-field equations are reviewed and compared to each other. The method can be used for the determination of phase diagrams (by comparing the stability of various types of long-range order), and the calculation of thermodynamic properties, one-particle Green's functions, and response functions. We review in detail the recent progress in understanding the Hubbard model and the Mott metal-insulator transition within this approach, including some comparison to experiments on three-dimensional transition-metal oxides. We present an overview of the rapidly developing field of applications of this method to other systems. The present limitations of the approach, and possible extensions of the formalism are finally discussed. Computer programs for the numerical implementation of this method are also provided with this article.
A Novel Planar Power Divider/Combiner for Wideband High-Power Applications

This manuscript presents a novel wideband power divider with high power handling capability. The power handling capacity of the power divider is increased through the use of grounded 50 ohm loads. The full circuit analysis of a single section of the proposed structure is presented utilizing even and odd modes and ABCD matrices. The final designed sections are cascaded and extended to achieve a high bandwidth response for the target of X-band. The structure was designed and optimized with the method of moments based on ADS software and simulated in HFSS for 3D full-wave analysis. A prototype module was fabricated and measured for experimental validation. The simulation results were confirmed by through measurements for the frequency band of 7–12 GHz (more than 52% fractional bandwidth). A divider such as the proposed one has a significantly higher power handling capacity than Wilkinson, as well as a wider frequency bandwidth than Gysel power dividers. As a wideband high-power power divider, the proposed device is ideal for high-data rate radar or satellite applications.
Numerical Simulations of Flare-productive Active Regions: δ-sunspots, Sheared Polarity Inversion Lines, Energy Storage, and Predictions

Solar active regions (ARs) that produce strong flares and coronal mass ejections (CMEs) are known to have a relatively high non-potentiality and are characterized by δ-sunspots and sheared magnetic structures. In this study, we conduct a series of flux emergence simulations from the convection zone to the corona and model four types of active regions that have been observationally suggested to cause strong flares, namely the spot–spot, spot–satellite, quadrupole, and inter-AR cases. As a result, we confirm that δ-spot formation is due to the complex geometry and interaction of emerging magnetic fields, and we find that the strong-field, high-gradient, highly sheared polarity inversion line (PIL) is created by the combined effect of the advection, stretching, and compression of magnetic fields. We show that free magnetic energy builds up in the form of a current sheet above the PIL. It is also revealed that photospheric magnetic parameters that predict flare eruptions reflect the stored free energy with high accuracy, while CME-predicting parameters indicate the magnetic relationship between flaring zones and entire ARs.
A novel motor fault diagnosis method based on principal component analysis (PCA) with a discrete belief rule base (DBRB) system

Motor vibration signal data sets are characteristically random and nonlinear, and its features are difficult to extract for fault identification. To reduce the uncertainty of fault diagnosis, a method based on principal component analysis (PCA) and discrete belief rule base (DBRB) was developed for the first time. Initially, the vibration signal was first denoised using a wavelet threshold algorithm to eliminate interference. Second, overlapping signals were segmented into 15 time windows and a total of 13 typical time domain features and mathematical statistical features were extracted. Third, the dimensions of the features were reduced to three principal components by PCA and were taken as the antecedent attributes of the DBRB. However, the amount of information in each principal component is different, so the variance contribution rate was taken as an antecedent attribute weight to restore the original data characteristics. Fourth, a PCA-DBRB model was established, which effectively avoided the combinatorial explosion problem of rule base in the DBRB model. In addition, to obtain appropriate reference values, the k-means algorithm was introduced to take the cluster centers as reference values. The method was then validated by collecting typical fault data from motor bench experiments. The results demonstrated that compared with other traditional classifiers, this approach is more effective and superior in classification performance and more accurate in diagnosing faults from motor vibration data.
Multi-joint isometric measurement for the evidence-based assessment of upper limb strength impairment in wheelchair athletes with different health conditions: a preliminary study

The present study presents a novel specific multi-joint isometric test to assess upper limb strength impairment for evidence-based classification in wheelchair sports. Sixteen wheelchair athletes participated in this study and were classified according to their type of physical impairment and health condition as follows: athletes with neurological impairment (ANI, n = 5) and athletes with impaired muscle power (IMP, n = 11). In addition, six non-disabled participants formed a control group (CG, n = 6). All the participants performed the isometric propulsion strength test (IPST), evaluating pushing and pulling actions, and two wheelchair performance tests. Excellent relative intra-session reliability scores were obtained for strength values for the ANI, IMP and CG groups (0.90 < ICC < 0.99) and absolute reproducibility showed acceptable scores of SEM (< 9.52%) for IPST pushing action. The ANI had significantly lower scores in strength and wheelchair performance than the IMP and the CG, while no differences were found between the IMP and the non-disabled participants. In addition, no correlations were found for wheelchair athletes between the isometric upper limb strength measure and wheelchair performance. Our findings suggest that the IPST is a valid test for strength measurement in upper limb impairment wheelchair athletes with different health conditions, which must be used in combination with a performance test to obtain a holistic assessment of this population.
“The Shelves Are Bare”: The Impact of COVID-19 on Families Enrolled in a Pediatric Produce Prescription Program

Objectives A large pediatric clinic in Flint, Michigan, implemented a produce prescription program for youth to address enduring challenges with food access and food insecurity. Approximately 18 months later, on March 23, 2020, the State of Michigan issued a “stay home, stay safe” executive order in response to the COVID-19 pandemic. This study sought to (1) explore caregiver experiences with access to and utilization of the prescription program during COVID-19; and (2) understand perceived changes in the food environment during the “stay home, stay safe” executive order. Methods Researchers collected data through recorded, semi-structured telephone interviews with caregivers of children who received at least one produce prescription and had previously enrolled in a preliminary effectiveness study on the prescription program. We transcribed the recordings verbatim for textual analysis. Examining the qualitative data using thematic analysis, we identified patterns across transcripts and formulated illustrative themes. Results Fifty-six caregivers (mean age, 41.3 ± 10.3 years) participated in interviews. The majority were female (91%), African American (70%), and Flint residents (75%). Recurrent themes, each centered around changes in the food environment resulting from COVID-19, emerged: (1) produce prescription access and utilization; (2) food access constraints; (3) food shopping adjustments; and (4) food insecurity stress. Perceived consequences of COVID-19 included increased anxiety related to food shopping and food insecurity alongside challenges accessing and utilizing the produce prescription program. Conclusions This study highlights the many ramifications of the COVID-19 pandemic on vulnerable families. More comprehensive efforts are necessary to address substantial barriers to healthy food access and affordability caused by the recent pandemic.
Understanding Information Flow in Cascades Using Network Motifs

A growing set of applications consider the process of network formation by using subgraphs as a tool for generating the network topology. One of the pressing research challenges is thus to be able to use these subgraphs to understand the network topology of information cascades which ultimately paves the way to theorize about how information spreads over time. In this paper, we make the first attempt at using network motifs to understand whether or not they can be used as generative elements for the diffusion network organization during different phases of the cascade lifecycle. In doing so, we propose a motif percolation-based algorithm that uses network motifs to measure the extent to which they can represent the temporal cascade network organization. We compare two phases of the cascade lifecycle from the perspective of diffusion-- the phase of steep growth and the phase of inhibition prior to its saturation. Our experiments on a set of cascades from the Weibo platform and with 5-node motifs demonstrate that there are only a few specific motif patterns with triads that are able to characterize the spreading process and hence the network organization during the inhibition region better than during the phase of high growth. In contrast, we do not find compelling results for the phase of steep growth.
Generating droplets in two-dimensional ising spin glasses using matching algorithms

We study the behavior of droplets for two-dimensional Icing spin glasses with Gaussian interactions. We use an exact matching algorithm which enables study of systems with linear dimension L up to 240, which is larger than is possible with other approaches. But the method only allows certain classes of droplets to be generated. We study single-bond, cross, and a category of fixed volume droplets as well as first excitations. By comparison with similar or equivalent droplets generated in previous works, the advantages but also the limitations of this approach are revealed. In particular we have studied the scaling behavior of the droplet energies and droplet sizes. In most cases, a crossover of the data can be observed such that for large sizes the behavior is compatible with the one-exponent scenario of the droplet theory. Only for the case of first excitations, no clear conclusion can be reached, probably because even with the matching approach the accessible system sizes are still too small.
Pricing Strategy for Energy Supplement Services of Hybrid Electric Vehicles Considering Bounded-Rationality and Energy Substitution Effect

Electric vehicles (EVs) have experienced rapid growth in recent years due to the concern about climate change. Meanwhile, hydrogen has become a versatile energy carrier that can be used in the EV industry. Thus, apart from pure EVs, hydrogen fuel cell EVs (FCEVs) and plug-in hybrid hydrogen and electric vehicles (PH2EVs) are also promising solutions for replacing gasoline vehicles. With the penetration of these alternative fuel vehicles, it is necessary to formulate proper strategies to guide EV charging and refueling. Hence, in this paper, a dynamic pricing strategy for integrated electricity charging and hydrogen refueling stations (IEHSs) is proposed to guide the charging/refueling decisions of a variety types of EVs and ensure the operation of IEHSs, power distribution network (PDN), and gas network (GN). First, a tri-level dynamic pricing strategy is proposed considering the interactions among EVs, IEHSs, and both PDN and GN. Second, the bounded rationality of EVs in station selection is modeled based on cognitive theory. Third, energy substitution for PH2EVs between electricity charging and hydrogen refueling is analyzed. Simulation results show that the proposed pricing strategy can increase the utility of EVs, enhance the profit of IEHSs, and mitigate the congestion of both PDN and GN.
Spectral Adversarial Training for Robust Graph Neural Network

Recent studies demonstrate that Graph Neural Networks (GNNs) are vulnerable to slight but adversarially designed perturbations, known as adversarial examples. To address this issue, robust training methods against adversarial examples have received considerable attention in the literature. Adversarial Training (AT) is a successful approach to learning a robust model using adversarially perturbed training samples. Existing AT methods on GNNs typically construct adversarial perturbations in terms of graph structures or node features. However, they are less effective and fraught with challenges on graph data due to the discreteness of graph structure and the relationships between connected examples. In this work, we seek to address these challenges and propose Spectral Adversarial Training (SAT), a simple yet effective adversarial training approach for GNNs. SAT first adopts a low-rank approximation of the graph structure based on spectral decomposition, and then constructs adversarial perturbations in the spectral domain rather than directly manipulating the original graph structure. To investigate its effectiveness, we employ SAT on three widely used GNNs. Experimental results on four public graph datasets demonstrate that SAT significantly improves the robustness of GNNs against adversarial attacks without sacrificing classification accuracy and training efficiency.
Host Molecule Incorporation into HIV Virions, Potential Influences in HIV Pathogenesis

During the last phase of HIV viral production, nascent HIV virions acquire a fraction of the cellular lipid membrane to create the external lipid envelope, a process by which cellular proteins present on the surface of the infected cell can be incorporated along with Env trimers. Interestingly, several studies indicated that these incorporated host molecules could conserve their biological activity and consequently contribute to HIV pathogenesis either by enhancing the infectivity of HIV virions, their tissue tropism or by affecting immune cell functions. The following review will describe the main approaches used to characterize membrane bound host molecule incorporation into HIV virions, the proposed mechanisms involved, and the role of a non-exhaustive list of incorporated molecules.
Electron scattering from acetylene: elastic integral and differential cross sections at low energies

Calculations have been carried out for the scattering of slow electrons from acetylene molecules in the gas phase, using the fixed-nuclei (FN) dynamical approximation and computing elastic cross sections only, integral and differential. Ab initio results at the exact static-exchange (ESE) level have been supplemented by a model local potential describing short-range and long-range polarization forces. The target wavefunction was obtained at the SCE level from a multicentre expansion over Gaussian orbitals (GTOs). Both the static and exchange interactions, Vst and Vex, were obtained from a discrete basis by using multicentre orbitals and the separable exchange approximation. The final results are compared with available experiments and a detailed search for the 2.6 eV shape resonance is discussed. The very-low-energy computed cross sections also reveal the presence of a Ramsauer-Townsend (RT) minimum.
Performance of reconstruction and identification of $\tau$ leptons decaying to hadrons and $\nu_\tau$ in pp collisions at $\sqrt{s}=$ 13 TeV

The algorithm developed by the CMS Collaboration to reconstruct and identify $\tau$ leptons produced in proton-proton collisions at $\sqrt{s}=$ 7 and 8 TeV, via their decays to hadrons and a neutrino, has been significantly improved. The changes include a revised reconstruction of $\pi^0$ candidates, and improvements in multivariate discriminants to separate $\tau$ leptons from jets and electrons. The algorithm is extended to reconstruct $\tau$ leptons in highly Lorentz-boosted pair production, and in the high-level trigger. The performance of the algorithm is studied using proton-proton collisions recorded during 2016 at $\sqrt{s}=$ 13 TeV, corresponding to an integrated luminosity of 35.9 fb$^{-1}$. The performance is evaluated in terms of the efficiency for a genuine $\tau$ lepton to pass the identification criteria and of the probabilities for jets, electrons, and muons to be misidentified as $\tau$ leptons. The results are found to be very close to those expected from Monte Carlo simulation.
Transition between Kerr comb and stimulated Raman comb in a silica whispering gallery mode microcavity

We theoretically and experimentally investigated the transition between modulation instability and Raman gain in a small silica microcavity with a large free-spectral range, which reveals that we can selectively switch from a four-wave mixing dominant state to a stimulated Raman scattering dominant state. Both the theoretical analysis and the experiment show that a Raman-dominant region is present between transitions of Kerr combs with different free-spectral range spacings. We can obtain a stable Kerr comb and a stable Raman state selectively by changing the driving power, coupling between the cavity and the waveguide, and laser detuning. Such a controllable transition is achieved thanks to the presence of gain competition between modulation instability and Raman gain in silica whispering gallery mode microcavities.