Miracle-dz/UniFAR-FTUs huggingface dataset:
On Predicting Long-Term Orbital Instability: A Relation Between the Lyapunov Time and Sudden Orbital Transitions

In three examples representative of Solar System dynamics, we find that the Lyapunov time, T L (i.e., the inverse of the Lyapunov exponent) and the time for an orbit to make a sudden transition T C are strongly correlated. The relation between the two times is T C ∞T L b , with b≅1.8. The first example examines asteroid orbits interior to Jupiter; the sudden transition occurs when the asteroid makes a close approach to Jupiter, which occurs close to the time when the asteroid's orbit crosses Jupiter's orbit
Free Vibration Analysis of Composite and Sandwich Plates by a Trigonometric Layerwise Deformation Theory and Radial Basis Functions

In this study trigonometric layerwise deformation theory is used for the analysis of free vibration of symmetric composite plates. A meshless discretization method based on global multiquadric radial basis functions is used. The equations of motion and the boundary conditions are derived and interpolated by radial basis functions. This method is applied to the free vibration analysis of composite and sandwich plates. The results are then compared with analytical and numerical solutions. The results show that the use of trigonometric layerwise deformation theory discretized with multiquadrics provides very good solutions for the free vibration of composite and sandwich plates.
Analytic and divided listening in normal-hearing and hearing-impaired listeners measured in a nonspeech pattern identification task

In multisource listening environments, it is important to be able to attend to a single sound source (analytic listening) while concurrently monitoring unattended sources for potentially useful information (divided listening). Previous studies have indicated that hearing-impaired (HI) listeners have more difficulty with analytic listening than do normal-hearing (NH) listeners. Although central factors (e.g., selective attention and memory) clearly play a role, the extent to which differences in peripheral factors (e.g., auditory filter characteristics) contribute to this effect is not clear. In this study, performance in a closed-set nonspeech tonal pattern identification task was measured in NH and HI listeners for patterns centered at 850 and 3500 Hz. The frequency spacing among the tones forming the patterns was adjusted to equate performance across listeners at each center frequency separately to control for peripheral frequency resolution. Patterns were then played at both frequencies concurrently. L.
Domain Walls Creep in Thin Ferroelectric Films

The switching processes in lead titanate thin films in subcritical rectangular pulsed fields have been investigated. Based on the obtained results, the dynamic exponent factor in the dependence of the domain wall velocity on the value of external field has been evaluated. It was shown that the value of the exponent factor increases as the film thickness decreases. The growth of the dynamic factor is associated with an increase in the crystallite axes orientation, when the thickness of polycrystalline films decreases.
Stimulation of electron Bernstein modes by perpendicular ion beams

This investigation studies the characteristics of electron cyclotron harmonic waves generated by almost monoenergetic perpendicular ion beams. Its motivation is twofold: (1) the new type of free energy source, beams made up of protons, alpha particles, and multiply ionized carbon, nytrogen or oxygen ions, has recently been observed in the geoplasma, and (2) the classical mechanism associated with the stimulation of these electrostatic modes is unable to explain some of their observed features, namely the fine structure sometimes seen in the emission bands and the occurrence of multiple harmonics with the higher branches lying above the upper hybrid frequency. The appropriate dispersion equation supports the developed analysis and determines the properties of this new excitation mechanism. Its characteristics contribute to overcome difficulties encountered by the standard paradigm in the interpretation of several types of electron Bernstein emissions.
Novel interferometric technique for the measurement of vibration and displacement of rotating components

In microelectronics, vacuum techniques such as turbo molecular pumps have to fulfill the demand of lowest vibrations. The standard measurement technique for this purpose is the laser Doppler vibrometer. However, vibration measurements of fast rotating objects such as vacuum pump shafts are challenging due to the laterally moving speckle pattern. In order to overcome this drawback, a novel non-incremental interferometric technique is presented for precise shape, vibration and displacement measurements of high speed rotating objects. Two inclined interference fringe systems are generated in one measurement volume. Their signal phase difference depends on the axial position and their signal frequency corresponds to the lateral velocity. Thus, simultaneous position and velocity measurements can be accomplished. However, the tilted interference fringe systems result in different speckle patterns and therefore in a low crosscorrelation coefficient of the scattering signals. Holographic methods have shown the way to overcome this problem. The scientific finding is to use different receiving angles in correspondence of the different inclination angles of the interference fringe systems in order to enhance the cross-correlation coefficient significantly. By this, to our best knowledge, worldwide unique method a standard position deviation of only 110 nm has been achieved also at high speeds over 10 m/s. Since the axial position and lateral velocity are measured simultaneously, shape and vibration measurements of rotating components can be accomplished by only one sensor. This non-incremental interferometric technique has been applied especially to vacuum pumps, rotating at 48,000 rpm. Substantial vibration evaluations of the rotating shaft have been performed.
Pulling a polymer with anisotropic stiffness near a sticky wall

We solve exactly a two-dimensional partially directed walk model of a semi-flexible polymer that has one end tethered to a sticky wall, while a pulling force away from the adsorbing surface acts on the free end of the walk. This model generalizes a number of previously considered adsorption models by incorporating individual horizontal and vertical stiffness effects, in competition with a variable pulling angle. A solution to the corresponding generating function is found by means of the kernel method. While the phases and related phase transitions are similar in nature to those found previously the analysis of the model in terms of its physical variables highlights various novel structures in the shapes of the phase diagrams and related behaviour of the polymer. We review the results of previously considered sub-cases, augmenting these findings to include analysis with respect to the model’s physical variables—namely, temperature, pulling force, pulling angle away from the surface, stiffness strength and the ratio of vertical to horizontal stiffness potentials, with our subsequent analysis for the general model focusing on the effect that stiffness has on this pulling angle range. In analysing the model with stiffness we also pay special attention to the case where only vertical stiffness is included. The physical analysis of this case reveals behaviour more closely resembling that of an upward pulling force acting on a polymer than it does of a model where horizontal stiffness acts. The stiffness–temperature phase diagram exhibits re-entrance for low temperatures, previously only seen for three-dimensional or co-polymer models. For the most general model we delineate the shift in the physical behaviour as we change the ratio of vertical to horizontal stiffness between the horizontal-only and the vertical-only stiffness regimes. We find that a number of distinct physical characteristics will only be observed for a model where the vertical stiffness dominates the horizontal stiffness.
Impact Assessment of Ease and Usefulness of Online Teaching in Higher Education in Post COVID Era

During COVID-19 and its resulting lockdown, the sudden closure of traditional offline classes resulted in the loss of education. Consequently, teaching pedagogies were unexpectedly changed, and a sudden shift towards online teaching was necessitated. The extensive availability of devices and applications made this shift easy. Nevertheless, all teachers were not equally equipped with the equivalent knowledge and resources, which could have affected their behavioral intention to continue online teaching in the future. This paper investigates the perception of university teachers to continue online teaching in higher education post-COVID. To accomplish this target, a mixed research approach was adopted. For quantitative data, 243 questionnaires were successfully collected from teachers of the top five central universities in India, using an online survey through Google forms by integrating the technology acceptance model (TAM). For qualitative data, online-focused group discussions (FGDs) with around seven teachers from different nations’ universities were done. This study is cross-sectional, utilizing TAM factors for ascertaining teachers’ behavioral intentions in India. All hypotheses were found significant by applying PLS-based SEM using smart-PLS software. This indicates that perceived usefulness and ease of use significantly impact attitude towards online teaching; further, perceived usefulness and attitude towards online teaching also significantly affect the behavioral intention of teachers to continue online teaching post-COVID era. The study helps educational institutions and respective national policymakers to define the future course of action in the education sector.
Pressure and Temperature Induced Phase Transition of ZnS from First-Principles Calculations

The pressure induced phase transition of ZnS from the wurtzite (WZ) and the zincblende (ZB) structures to the rocksalt (RS) structure and the temperature induced phase transition from the ZB structure to the WZ structure are investigated by ab initio plane-wave pseudopotential density-functional theory (DFT), together with the quasi-harmonic Debye model. It is found that the zero-temperature transition pressures from the WZ-ZnS and the ZB-ZnS to the RS-ZnS are 17.20 and 17.37 GPa, respectively. The zero-pressure transition temperature from the ZB-ZnS to the WZ-ZnS is 1199 K. All these results are consistent with the available experimental data. Moreover, the dependences of the normalized primitive cell volume V/V0 on pressure and thermal expansion coefficient α on temperature are also obtained successfully.
An Iterative Method for Finding Stationary Values of a Function of Several Variables

Eighteen months ago Rosenbrock (1960) published a paper in this journal on finding the greatest or least value of a function of several variables. A number of methods were listed and they all have first-order convergence. Six months ago Martin and Tee (1961) published a paper in which they mentioned gradient methods which have second-order convergence for finding the minimum of a quadratic positive definite function. In this paper will be described an iterative method which is not unlike the conjugate gradient method of Hestenes and Stiefel (1952), and which finds stationary values of a general function. It has second-order convergence, so near a stationary value it converges more quickly than Rosenbrock's variation of the steepest descents method and, although each iteration is rather longer because the method is applicable to a general function, the rate of convergence is comparable to that of the more powerful of the gradient methods described by Martin and Tee.
A Case of Cannabinoid Hyperemesis Syndrome and Acute Kidney Injury: A Review of the Literature

Cannabis is a commonly used illicit drug worldwide with many noted adverse effects and medical properties. It has been previously used in medicine for the management of chemotherapy-induced nausea and vomiting. The chronic use of cannabis is well-known to be associated with psychological and cognitive adverse effects, however, cannabinoid hyperemesis syndrome is a less commonly recognized complication of chronic long-term use of cannabis, though it does not occur in the majority of chronic cannabis users. Here we present the case of a 42-year-old male who presented with classical clinical features of cannabinoid hyperemesis syndrome.
The Empirical Power and Type I Error Rates of the GBT and ω Indices in Detecting Answer Copying on Multiple-Choice Tests

The generalized binomial test (GBT) and ω indices are the most recent methods suggested in the literature to detect answer copying behavior on multiple-choice tests. The ω index is one of the most studied indices, but there has not yet been a systematic simulation study for the GBT index. In addition, the effect of the ability levels of the examinees in answer copying pairs on the statistical properties of the GBT and ω indices have not been systematically addressed as yet. The current study simulated 500 answer copying pairs for each of 1,440 conditions (12 source ability level × 12 cheater ability level × 10 amount of copying) to study the empirical power and 10,000 pairs of independent response vectors for each of 144 conditions (12 source ability level × 12 cheater ability level) to study the empirical Type I error rates of the GBT and ω indices. Results indicate that neither GBT nor ω inflated the Type I error rates, and they are reliable to use in practice. The difference in statistical power of these two methods was very small, and GBT performs slightly better than does ω. The main effect for the amount of copying and the interaction effect between source ability level and the amount of copying are found to be very strong while all other main and interactions effects are negligible.
Direct observation of contact and channel resistance in pentacene four-terminal thin-film transistor patterned by laser ablation method

We established a dry-etching patterning process for the channel formation of pentacene thin-film transistor, and fabricated a four-terminal device equipped with a gate electrode. The four-terminal device enabled us to divide two-terminal source–drain resistance into two components of contact resistance and pentacene channel resistance. We obtained direct evidence of a gate-voltagedependent contact resistance change: the gate-induced charge significantly reduced the contact resistance and increased source–drain current. Furthermore, the temperature dependence of the device clearly indicated that the contact resistance was much higher than the channel resistance and was dominated in the two-terminal total resistance of the device below 120 K. An observed activation energy of 80 meV for contact resistance was higher than that of 42 meV for pentacene channel resistance.
Criteria for the existence of helical instabilities in subsonic impinging jets

Understanding instability modes in impinging jets is important for the design of advanced vertical takeoff and landing aircraft. Our initial experimental observations of helical modes in subsonic impinging jets were contrary to expectations based on published stability theory results. This paper focuses on the curious phenomenon of the occurrence of these, hitherto unexpected, helical modes in subsonic impinging jets and provides, both experimental and analytical proof for their existence. Past results, based on linear stability analysis, that call for an absence of helical modes in cold, subsonic impinging jets have been re-examined to reconcile new experimental data. Based on this re-examination, a new threshold Mach number has been proposed, above which helical modes are permissible. The revised theory put forth in this paper indicates that the threshold Mach number for the existence of the helical mode depends on the jet temperature and that this threshold decreases as the jet temperature increases. T.
Goodness-of-Fit Test for Exponentiality Based on Kullback–Leibler Information

Abstract In this paper, we discuss goodness-of-fit tests of the exponential distribution based on Kullback–Leibler information. To construct test statistics, Van Es' and Correa's entropy estimator are used as an estimator of Shannon's entropy. Critical values for various sample sizes determined by means of Monte Carlo simulations are presented for each of test statistics. Also, formulas for calculating approximate critical values for given sample sizes are provided for the respective test statistics. A Monte Carlo power analysis is performed for various alternatives and sample sizes in order to compare the proposed tests with several existing goodness-of-fit tests based on the empirical distribution function (EDF). Simulation results show that Kullback–Leibler information tests have higher powers than the EDF tests.
CREDIBILITY CLAIMS RESERVING WITH STOCHASTIC DIAGONAL EFFECTS

Abstract An interesting class of stochastic claims reserving methods is given by the models with conditionally independent loss increments (CILI), where the incremental losses are conditionally independent given a risk parameter Θi,j depending on both the accident year i and the development year j. The Bühlmann–Straub credibility reserving (BSCR) model is a particular case of a CILI model where the risk parameter is only depending on i. We consider CILI models with additive diagonal risk (ADR), where the risk parameter is given by the sum of two components, one depending on the accident year i and the other depending on the calendar year t = i + j. The model can be viewed as an extension of the BSCR model including random diagonal effects, which are often declared to be important in loss reserving but rarely are specifically modeled. We show that the ADR model is tractable in closed form, providing credibility formulae for the reserve and the mean square error of prediction (MSEP). We also derive unbiased estimators for the variance parameters which extend the classical Bühlmann–Straub estimators. The results are illustrated by a numerical example and the estimators are tested by simulation. We find that the inclusion of random diagonal effects can be significant for the reserve estimates and, especially, for the evaluation of the MSEP. The paper is written with the purpose of illustrating the role of stochastic diagonal effects. To isolate these effects, we assume that the development pattern is given. In particular, our MSEP values do not include the uncertainty due to the estimation of the development pattern.
Efficiency of nearest neighbour balanced block designs for correlated observations

SUMMARY Block designs for observations correlated in one dimension are investigated. Nearest neighbour balanced block designs turn out to be optimal for autoregressive correlation models when generalized least squares estimation is used. Performance of these designs for other correlation models is shown to be quite satisfactory. The efficiency of the proposed designs in comparison to the randomized block designs is computed and tabulated for some cases.
Line-of-sight velocity profiles in spherical galaxies: breaking the degeneracy between anisotropy and mass

A systematic study of the line profiles expected in the outer parts (RR c ) of non-rotating elliptical galaxies is reported. For a family of quasi-separable spherical models the line-of-sight velocity profiles l(v) are calculated analytically in both a Keplerian and a scale-free halo potential. These velocity profiles (VPs) can take a wide variety of shapes; they illustrate that tangentially anisotropic distribution functions (DFs) generally lead to VPs with flat tops, while radially anisotropic DFs lead to more nearly Gaussian VPs. Strongly radial DFs in a halo potential develop prominent wings. As a general rule these velocity profiles are sensitive to the anisotropy β of the model, less so to the stellar density profile and the potential, and least so to the form of the DF at fixed β
How Patronage Delivers: Political Appointments, Bureaucratic Accountability, and Service Delivery in Brazil

: The political appointment of bureaucrats is typically seen as jeopardizing development by selecting worse types into the bureaucracy or by depressing bureaucratic effort. I argue that political appointments also affect outcomes through a third, less studied channel, namely, by changing how bureaucrats work. Patronage provides connections between bureau-crats and politicians, and thereby grants access to material and nonmaterial resources, enhances monitoring, facilitates the application of sanctions and rewards, aligns priorities and incentives, and increases mutual trust. Political appointments can thus enhance bureaucrats’ accountability and effectiveness, not just for rent-seeking purposes but also, in certain conditions, for public service delivery. I test this theory using data on Brazilian municipal governments, leveraging two quasi-experiments, two original surveys of bureaucrats and politicians, and in-depth interviews. The findings highlight the countervailing effects of connections on bureaucratic governance in the developing world. Replication Materials: The materials required to verify the computational reproducibility of the results, procedures, and analyses in this article are available on the American Journal of Political Science Dataverse within the Harvard Database Network, at: https://doi.org/10.7910/DVN/GHJ8JL.
Riesz systems and moment method in the study of viscoelasticity in one space dimension

In this paper we study the equation of linear viscoelasticity and we prove that two sequences of functions, naturally associated with this equation, are Riesz systems. These sequences appear naturally when observability and controllability problems are reformulated in terms of suitable interpolation/moment problems. The key contribution of the paper is to be found in the way used to prove that the two sequences are Riesz systems, an idea already applied to the study of different control problems.
DeepDense: Enabling node embedding to dense subgraph mining

Dense subgraphs convey important information and insights about a graph structure. This explains why dense subgraph mining is a problem of key interest that arises in several tasks and applications such as graph visualization, graph summarization, graph clustering, and complex network analysis. It is a hard problem that has been intensively addressed by the data mining community. In this paper, we propose a deep learning approach that enumerates all occurrences of dense sub-graphs in a graph without any constraints or limitations on their size. More precisely, we enrich exiting structural node embedding with extra information, computed on node neighborhoods, to effectively capture their belonging to dense subgraphs. We evaluate our approach on several datasets to attest its eﬃciency on two main applications: graph summarization and graph clustering.
The Arctic on the fast track of change

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SimSel: a new simulation method for variable selection

We propose a new simulation method, SimSel, for variable selection in linear and nonlinear modelling problems. SimSel works by disturbing the input data with pseudo-errors. We then study how this disturbance affects the quality of an approximative model fitted to the data. The main idea is that disturbing unimportant variables does not affect the quality of the model fit. The use of an approximative model has the advantage that the true underlying function does not need to be known and that the method becomes insensitive to model misspecifications. We demonstrate SimSel on simulated data from linear and nonlinear models and on two real data sets. The simulation studies suggest that SimSel works well in complicated situations, such as nonlinear errors-in-variable models.