cssi/SciSciGPT-SciSciNet huggingface dataset:
A Counterexample to a Generalized Saari's Conjecture with a Continuum of Central Configurations

In this paper we show that in the n-body problem with harmonic potential one can find a continuum of central configurations for n= 3. Moreover we show a counterexample to an interpretation of Jerry Marsden Generalized Saari's conjecture. This will help to refine our understanding and formulation of the Generalized Saari's conjecture, and in turn it might provide insight in how to solve the classical Saari's conjecture for n≥ 4.
ORIGINS OF SCATTER IN THE RELATIONSHIP BETWEEN HCN 1-0 AND DENSE GAS MASS IN THE GALACTIC CENTER

We investigate the correlation of HCN 1-0 with dense gas mass in the Galactic center. We find that in general (on the ~10 pc size scale of individual molecular cloud cores) HCN 1-0 is well correlated with the dense molecular gas mass using a standard log-log relationship. However individual clouds in this environment show systematic deviations from this relationship that contribute to around 0.75 dex of scatter. Most notably, Sgr B2, the most massive cloud in the Galactic center, has an integrated HCN 1-0 intensity of cloud less than half its mass, and several other clouds including GCM-0.02-0.07 show an enhancement of HCN 1-0 by a factor of 2-3 relative to clouds of comparable mass. We also find that HCN 1-0 is more intense for a given mass in the large-scale diffuse emission in the central 300 parsecs compared to the compact emission from individual cloud cores. We identify the two primary sources of scatter in the relationship between HCN 1-0 and dense gas mass to be self-absorption (which reduces the observed HCN 1-0 intensity of Sgr B2) and variations in HCN abundance, which appear to increase the brightness of HCN 1-0 in GCM-0.02-0.07 and other clouds. We find that these sources of scatter would only contribute to an ~10% error in the dense gas mass inferred from the HCN 1-0 intensity in the Galactic center. However, the implied order of magnitude HCN abundance variations between Galactic center clouds, and the systematic nature of these variations warn of potential biases in the use of HCN as dense gas mass tracer in more extreme environments, such as AGN and shock-dominated regions. Finally, we also investigate other tracers having transitions near 3 mm, finding that HNCO, HNC and HCO+ largely behave like HCN, while HC3N, and CH3CN are higher fidelity tracers of the amount of gas in clouds like Sgr B2 that suffer from strong self-absorption of the HCN 1-0 line. [abridged]
Bridge number and Conway products

In this paper, we give a structure theorem for c-incompressible Conway spheres in link complements in terms of the standard height function on S . We go on to define the generalized Conway product K1 c K2 of two links K1 and K2 . Provided K1 c K2 satisfies minor additional hypotheses, we prove the lower bound ˇ.K1 c K2/ ˇ.K1/ 1 for the bridge number of the generalized Conway product where K1 is the distinguished factor. Finally, we present examples illustrating that this lower bound is tight.
THE LINK BETWEEN PLANETARY SYSTEMS, DUSTY WHITE DWARFS, AND METAL-POLLUTED WHITE DWARFS

It has long been suspected that metal-polluted white dwarfs (types DAZ, DBZ, and DZ) and white dwarfs with dusty disks possess planetary systems, but a specific physical mechanism by which planetesimals are perturbed close to a white dwarf has not yet been fully posited. In this paper, we demonstrate that mass loss from a central star during post-main-sequence evolution can sweep planetesimals into interior mean motion resonances with a single giant planet. These planetesimals are slowly removed through chaotic excursions of eccentricity that in time create radial orbits capable of tidally disrupting the planetesimal. Numerical N-body simulations of the solar system show that a sufficient number of planetesimals are perturbed to explain white dwarfs with both dust and metal pollution, provided other white dwarfs have more massive relic asteroid belts. Our scenario requires only one Jupiter-sized planet and a sufficient number of asteroids near its 2:1 interior mean motion resonance. Finally, we show that once a planetesimal is perturbed into a tidal crossing orbit, it will become disrupted after the first pass of the white dwarf, where a highly eccentric stream of debris forms the main reservoir for dust-producing collisions. These simulations, in concert with observations of white dwarfs, place interesting limits on the frequency of planetary systems around main-sequence stars, the frequency of planetesimal belts, and the probability that dust may obscure future terrestrial planet finding missions.
Theory of activated glassy dynamics in randomly pinned fluids

We generalize the force-level, microscopic, Nonlinear Langevin Equation (NLE) theory and its elastically collective generalization [elastically collective nonlinear Langevin equation (ECNLE) theory] of activated dynamics in bulk spherical particle liquids to address the influence of random particle pinning on structural relaxation. The simplest neutral confinement model is analyzed for hard spheres where there is no change of the equilibrium pair structure upon particle pinning. As the pinned fraction grows, cage scale dynamical constraints are intensified in a manner that increases with density. This results in the mobile particles becoming more transiently localized, with increases of the jump distance, cage scale barrier, and NLE theory mean hopping time; subtle changes of the dynamic shear modulus are predicted. The results are contrasted with recent simulations. Similarities in relaxation behavior are identified in the dynamic precursor regime, including a roughly exponential, or weakly supra-exponential, growth of the alpha time with pinning fraction and a reduction of dynamic fragility. However, the increase of the alpha time with pinning predicted by the local NLE theory is too small and severely so at very high volume fractions. The strong deviations are argued to be due to the longer range collective elasticity aspect of the problem which is expected to be modified by random pinning in a complex manner. A qualitative physical scenario is offered for how the three distinct aspects that quantify the elastic barrier may change with pinning. ECNLE theory calculations of the alpha time are then presented based on the simplest effective-medium-like treatment for how random pinning modifies the elastic barrier. The results appear to be consistent with most, but not all, trends seen in recent simulations. Key open problems are discussed with regard to both theory and simulation.
Constraining inflationary dark matter in the luminogenesis model

Using renormalization-group flow and cosmological constraints on inflation models, we exploit a unique connection between cosmological inflation and the dynamical mass of dark matter particles in the luminogenesis model, a unification model with the gauge group SU(3)C × SU(6) × U(1)Y, which breaks to the Standard Model with an extra gauge group for dark matter when the inflaton rolls into the true vacuum. In this model, inflaton decay gives rise to dark matter, which in turn decays to luminous matter in the right proportion that agrees with cosmological data. Some attractive features of this model include self-interacting dark matter, which may resolve the problems of dwarf galaxy structures and dark matter cusps at the centers of galaxies.
Statistics of the general circulation from cumulant expansions.

Large-scale atmospheric flows may not be so nonlinear as to preclude their statistical description by systematic expansions in cumulants. I extend previous work by examining a two-layer baroclinic model of the general circulation. The fixed point of the cumulant expansion describes the statistically steady state of the out-of-equilibrium model. Equal-time statistics so obtained agree well with those accumulated by direct numerical simulation.
Electronic structure of lanthanide scandates

X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and density functional theory calculations were used to study the electronic structure of three lanthanide scandates: $\mathrm{GdSc}{\mathrm{O}}_{3},\mathrm{TbSc}{\mathrm{O}}_{3}$, and $\mathrm{DySc}{\mathrm{O}}_{3}$. X-ray photoelectron spectra simulated from first-principles calculations using a combination of on-site hybrid and $\mathrm{GGA}+U$ methods were found to be in good agreement with experimental x-ray photoelectron spectra. The hybrid method was used to model the ground state electronic structure and the $\mathrm{GGA}+U$ method accounted for the shift of valence state energies due to photoelectron emission via a Slater-Janak transition state approach. From these results, the lanthanide scandate valence bands were determined to be composed of $\mathrm{Ln}4f,\mathrm{O}2p$, and $\mathrm{Sc}3d$ states, in agreement with previous work. However, contrary to previous work the minority $\mathrm{Ln}4f$ states were found to be located closer to, and in some cases at, the valence band maximum. This suggests that minority $\mathrm{Ln}4f$ electrons may play a larger role in lanthanide scandate properties than previously thought.
A Photometric, Spectroscopic, and Apsidal Motion Analysis of the F-type Eclipsing Binary BW Aquarii from K2 Campaign 3

Eclipsing binaries are important tools for studying stellar evolution and stellar interiors. Their accurate fundamental parameters are used to test evolutionary models, and systems showing apsidal motion can also be used to test the model's internal structure predictions. For this purpose, we present a photometric and spectroscopic analysis of the eclipsing binary BW Aquarii, an evolved F-type binary with slow apsidal motion. We model the K2 C3 light curve using the Eclipsing Light Curve code to determine several orbital and stellar parameters, as well as measure the eclipse times to determine updated apsidal motion parameters for the system. Furthermore, we obtain high-resolution spectra of BW Aqr using the CHIRON echelle spectrograph on the CTIO 1.5m for radial velocity analysis. We then reconstruct the spectra of each component using Doppler tomography in order to determine the atmospheric parameters. We find that both components of BW Aqr are late F-type stars with M1 = 1.365 +/- 0.008 Msun, M2 = 1.483 +/- 0.009 Msun, and R1 = 1.782 +/- 0.021 Rsun, R2 = 2.053 +/- 0.020 Rsun. We then compare these results to the predictions of several stellar evolution models, finding that the models cannot reproduce the observed properties of both components at the same age.
Relativistic Effects on the Appearance of a Clothed Black Hole

For an accretion disk around a black hole, the strong relativistic effects affect every aspect of the radiation from the disk, including its spectrum, light-curve, and image. This work investigates in detail how the images will be distorted, and what the observer will see from different viewing angles and in different energy bands.
Chirality through classical physics

Chirality, or handedness, is a topic that is common in biology and chemistry, yet is rarely discussed in physics courses. We provide a way of introducing the topic in classical physics, and demonstrate the merits of its inclusion - such as a simple way to visually introduce the concept of symmetries in physical law - along with giving some simple proofs using only basic matrix operations, thereby avoiding the full formalism of the three-dimensional point group.
Dynamic General Equilibrium Modeling of Long and Short-Run Historical Events

Abstract We provide quantitative analyses of two striking historical episodes, the timing of the Industrial Revolution in England, and the sources of U.S. economic fluctuations between 1889-1929. Applying data from 1245-1845 within the “Malthus to Solow” framework shows that the timing of the Industrial Revolution reflects a subtle interplay between large changes in TFP and deaths from plagues. We find that U.S. economic fluctuations, including the Panics of 1893 and 1907, were driven primarily by volatile TFP, and that growth during the “Roaring Twenties” should have been even stronger, reflecting a large labor wedge that emerged around World War I.
THE SUBMILLIMETER POLARIZATION SPECTRUM OF M17

We present 450 μm polarimetric observations of the M17 molecular cloud obtained with the SHARP polarimeter at the Caltech Submillimeter Observatory. Across the observed region, the magnetic field orientation is consistent with previous submillimeter and far-infrared polarization measurements. Our observations are centered on a region of the molecular cloud that has been compressed by stellar winds from a cluster of OB stars. We have compared these new data with previous 350 μm polarimetry and find an anti-correlation between the 450 and 350 μm polarization magnitude ratio and the ratio of 21 cm to 450 μm intensity. The polarization ratio is lower near the east end of the studied region where the cloud is exposed to stellar winds and radiation. At the west end of the region, the polarization ratio is higher. We interpret the varying polarization spectrum as evidence supporting the radiative alignment torque model for grain alignment, implying higher alignment efficiency in the region that is exposed to a higher anisotropic radiation field.
Development of quantum perspectives in modern physics

Introductory undergraduate courses in classical physics stress a perspective that can be characterized as realist; from this perspective, all physical properties of a classical system can be simultaneously specified and thus determined at all future times. Such a perspective can be problematic for introductory quantum physics students, who must develop new perspectives in order to properly interpret what it means to have knowledge of quantum systems. We document this evolution in student thinking in part through pre- and post-instruction evaluations using the Colorado Learning Attitudes about Science Survey. We further characterize variations in student epistemic and ontological commitments by examining responses to two essay questions, coupled with responses to supplemental quantum attitude statements. We find that, after instruction in modern physics, many students are still exhibiting a realist perspective in contexts where a quantum-mechanical perspective is needed. We further find that this effect can be significantly influenced by instruction, where we observe variations for courses with differing learning goals. We also note that students generally do not employ either a realist or a quantum perspective in a consistent manner.
Two dimensional fermions in four dimensional YM

Dirac fermions in the fundamental representation of SU(N) live on a two dimensional torus flatly embedded in R4. They interact with a four dimensional SU(N) Yang Mills vector potential preserving a global chiral symmetry at finite N. As the size of the torus in units of 1/ΛSU(N) is varied from small to large, the chiral symmetry gets spontaneously broken in the infinite N limit.
Elliptic Genus of Phases of N = 2 Theories

We discuss an algebro-geometric description of Witten’s phases of N = 2 theories and propose a definition of their elliptic genus provided some conditions on singularities of the phases are met. For Landau–Ginzburg phase one recovers elliptic genus of LG models proposed in physics literature in early 1990s. For certain transitions between phases we derive invariance of elliptic genus from an equivariant form of McKay correspondence for elliptic genus. As special cases one obtains Landau–Giznburg/Calabi–Yau correspondence for elliptic genus of weighted homogeneous potentials as well as certain hybrid/CY correspondences.
Efficient Computation of Limit Spectra of Sample Covariance Matrices

Models from random matrix theory (RMT) are increasingly used to gain insights into the behavior of statistical methods under high-dimensional asymptotics. However, the applicability of the framework is limited by numerical problems. Consider the usual model of multivariate statistics where the data is a sample from a multivariate distribution with a given covariance matrix. Under high-dimensional asymptotics, there is a deterministic map from the distribution of eigenvalues of the population covariance matrix (the population spectral distribution or PSD), to the of empirical spectral distribution (ESD). The current methods for computing this map are inefficient, and this limits the applicability of the theory. We propose a new method to compute numerically the ESD from an arbitrary input PSD. Our method, called SPECTRODE, finds the support and the density of the ESD to high precision; we prove this for finite discrete distributions. In computational experiments SPECTRODE outperforms existing methods by orders of magnitude in speed and accuracy. We apply it to compute expectations and contour integrals of the ESD, which are often central in applications. We also illustrate that SPECTRODE is directly useful in statistical problems, such as estimation and hypothesis testing for covariance matrices. Our proposal, implemented in open source software, may broaden the use of RMT in high-dimensional data analysis.
Detecting Gravitational Scattering of Interstellar Objects Using Pulsar Timing

Gravitational scattering events, in which the path of an interstellar object is deflected by a pulsar or the solar system, give rise to reflex motion which can potentially be detected using pulsar timing. We determine the form of the timing signal expected from a gravitational scattering event, which is ramp-like and resembles the signal produced by a glitch or a gravitational wave burst with memory (BWM), and investigate the prospects for detecting such a signal using a pulsar timing array. The level of timing precision currently achieved for some millisecond pulsars makes it possible to detect objects as small as $10^{-10}$ solar masses, less than the mass of the dwarf planet Ceres, at impact parameters as large as 1 AU. The signals produced by gravitational scattering could provide independent constraints on models of dark matter involving asteroid-mass objects or subhalos, and should be considered as potential false positives in searches for BWMs.
Merging massive black holes the right place and the right time

The LIGO/Virgo detections of gravitational waves from merging black holes of ≃ 30 solar mass suggest progenitor stars of low metallicity (Z/Z⊙ ≲ 0.3). In this talk I will provide constrains on where the progenitors of GW150914 and GW170104 may have formed, based on advanced models of galaxy formation and evolution combined with binary population synthesis models. First I will combine estimates of galaxy properties (star-forming gas metallicity, star formation rate and merger rate) across cosmic time to predict the low redshift BBH merger rate as a function of present day host galaxy mass, formation redshift of the progenitor system and different progenitor metallicities. I will show that the signal is dominated by binaries formed at the peak of star formation in massive galaxies with and binaries formed recently in dwarf galaxies. Then, I will present what very high resolution hydrodynamic simulations of different galaxy types can learn us about their black hole populations.
The Masses of Supernova Remnant Progenitors in M83

We determine the ages of the young, resolved stellar populations at the locations of 237 optically-identified supernova remnants in M83. These age distributions put constraints on the progenitor masses of the supernovae that produced 199 of the remnants. The other 38 show no evidence for having a young progenitor and are therefore good Type Ia SNR candidates. Starting from Hubble Space Telescope broadband imaging, we measured resolved stellar photometry of seven archival WFC3/UVIS fields in F336W, F438W, and F814W. We generate color-magnitude diagrams of the stars within 50 pc of each SNR and fit them with stellar evolution models to obtain the population ages. From these ages we infer the progenitor mass that corresponds to the lifetime of the most prominent age that is $ $15 M$_{\odot}$, and 5 of these are $>$15 M$_{\odot}$ at 84% confidence. This is the largest collection of high-mass progenitors to date, including our highest-mass progenitor inference found so far, with a constraint of $<$8 Myr. Overall, the distribution of progenitor masses has a power-law index of $-3.0^{+0.2}_{-0.7}$, steeper than Salpeter initial mass function ($-2.35$). It remains unclear whether the reason for the low number of high-mass progenitors is due to the difficulty of finding and measuring such objects or because only a fraction of very massive stars produce supernovae.
Sensitive Dependence of Optimal Network Dynamics on Network Structure

The relationship between the structure and dynamics of a network is key to understanding the behavior of complex systems. A new analysis shows how network optimization, whether designed or evolved, can lead to collective dynamics that depend sensitively on the structure of the network.
In the Presence of a Wrecking Ball: Orbital Stability in the HR 5183 System

Discoveries of exoplanets using the radial velocity method are progressively reaching out to increasingly longer orbital periods as the duration of surveys continues to climb. The improving sensitivity to potential Jupiter analogs is revealing a diversity of orbital architectures that are substantially different from that found in our solar system. An excellent example of this is the recent discovery of HR 5183b: a giant planet on a highly eccentric (e = 0.84) ~75 yr orbit. The presence of such giant planet orbits are intrinsically interesting from the perspective of the dynamical history of planetary systems, and also for examining the implications of ongoing dynamical stability and habitability of these systems. In this work, we examine the latter, providing results of dynamical simulations that explore the stable regions that the eccentric orbit of the HR 5183 giant planet allows to exist within the habitable zone (HZ) of the host star. Our results show that, despite the incredible perturbing influence of the giant planet, there remain a narrow range of locations within the HZ where terrestrial planets may reside in long-term stable orbits. We discuss the effects of the giant planet on the potential habitability of a stable terrestrial planet, including the modulation of terrestrial planet eccentricities and the periodically spectacular view of the giant planet from the terrestrial planet location.
The experimental status of direct searches for exotic physics beyond the standard model at the Large Hadron Collider

Abstract The standard model of particle physics is an extremely successful theory of fundamental interactions, but it has many known limitations. It is therefore widely believed to be an effective field theory that describes interactions near the TeV scale. A plethora of strategies exist to extend the standard model, many of which contain predictions of new particles or dynamics that could manifest in proton-proton collisions at the Large Hadron Collider (LHC). As of now, none have been observed, and much of the available phase space for natural solutions to outstanding problems is excluded. If new physics exists, it is therefore either heavy (i.e. above the reach of current searches) or hidden (i.e. currently indistinguishable from standard model backgrounds). We summarize the existing searches, and discuss future directions at the LHC.
Properties and Bayesian fitting of restricted Boltzmann machines

A restricted Boltzmann machine (RBM) is an undirected graphical model constructed for discrete or continuous random variables, with two layers, one hidden and one visible, and no conditional dependency within a layer. In recent years, RBMs have risen to prominence due to their connection to deep learning. By treating a hidden layer of one RBM as the visible layer in a second RBM, a deep architecture can be created. RBMs are thought to thereby have the ability to encode very complex and rich structures in data, making them attractive for supervised learning. However, the generative behavior of RBMs is largely unexplored and typical fitting methodology does not easily allow for uncertainty quantification in addition to point estimates. In this paper, we discuss the relationship between RBM parameter specification in the binary case and model properties such as degeneracy, instability and uninterpretability. We also describe the associated difficulties that can arise with likelihood-based inference and further discuss the potential Bayes fitting of such (highly flexible) models, especially as Gibbs sampling (quasi-Bayes) methods are often advocated for the RBM model structure.
Orphan Afterglows of Collimated Gamma-Ray Bursts: Rate Predictions and Prospects for Detection

We make a quantitative prediction for the detection rate of orphan gamma-ray burst (GRB) afterglows as a function of flux sensitivity in X-ray, optical, and radio wave bands, based on a recent model of collimated GRB afterglows. We find that the orphan afterglow rate strongly depends on the opening angle of the jet (roughly ?), as expected from simple geometrical consideration, if the total jet energy is kept constant as suggested by recent studies. The relative beaming factor brel, i.e., the ratio of all afterglow rates including orphans to those associated with observable prompt GRBs, could be as high as brel 100 for searches deeper than R ~ 24, depending on afterglow parameters. To make the most plausible predictions, we average the model emission for 10 sets of afterglow parameters obtained through fits to 10 well-observed, collimated GRB jets, weighted by the sky coverage of each jet. Our model expectations are consistent with the results (or constraints) obtained by all past searches. We estimate the number of orphan afterglows in the first 1500 deg2 field of the Sloan Digital Sky Survey (SDSS) to be about 0.2. The relative beaming factor brel is rapidly increasing with the search sensitivity: brel ~ 3 for the SDSS sensitivity to transient objects in the northern sky (R ~ 19), ~14 for the past high-z supernova searches (R ~ 23), and ~50 for the sensitivity of the Subaru Suprime-Cam (R ~ 26). Predictions are made for the current facilities and future projects in X-ray, optical, and radio bands. Among them, the southern sky observation of the SDSS (sensitive to transients down to R ~ 23) could detect ~40 orphan afterglows during the 5 yr operation. The Allen Telescope Array would find about 200 afterglows in a radio band at ~0.1-1 mJy with brel ~ 15.
ON DISCOVERING ELECTROMAGNETIC EMISSION FROM NEUTRON STAR MERGERS: THE EARLY YEARS OF TWO GRAVITATIONAL WAVE DETECTORS

We present the first simulation addressing the prospects of finding an electromagnetic (EM) counterpart to gravitational wave (GW) detections during the early years of only two advanced detectors. The perils of such a search may have appeared insurmountable when considering the coarse ring-shaped GW localizations spanning thousands of square degrees using time-of-arrival information alone. Leveraging the amplitude and phase information of the predicted GW signal narrows the localization to arcs with a median area of only a few hundred square degrees, thereby making an EM search tractable. Based on the locations and orientations of the two LIGO detectors, we find that the GW sensitivity is limited to only two of the four sky quadrants. Thus, the rates of GW events with two interferometers is only ≈40% of the rate with three interferometers of similar sensitivity. Another important implication of the sky quadrant bias is that EM observatories in North America and Southern Africa would be able to systematically respond to GW triggers several hours sooner than Russia and Chile. Given the larger sky areas and the relative proximity of detected mergers, 1 m class telescopes with very wide-field cameras are well-positioned for the challenge of finding an EM counterpart. Identification of the EM counterpart amidst the larger numbers of false positives further underscores the importance of building a comprehensive catalog of foreground stellar sources, background active galactic nucleus and potential host galaxies in the local universe. This initial study is based on a small sample of 17 detected mergers; future works will expand this sample.
CONTINUOUS LOWER BOUNDS FOR MOMENTS OF ZETA AND L -FUNCTIONS.

We obtain lower bounds of the correct order of magnitude for the 2k-th moment of the Riemann zeta function for all k ‚ 1. Previously such lower bounds were known only for rational values of k, with the bounds depending on the height of the rational number k. Our new bounds are continuous in k, and thus extend also to the case when k is irrational. The method is a refinement of an approach of Rudnick and Soundararajan, and applies also to moments of L-functions in families.
Effect of School-Based Body Mass Index Reporting in California Public Schools: A Randomized Clinical Trial.

Importance Annually, US schools screen millions of students’ body mass index (BMI) and report the results to parents, with little experimental evidence on potential benefits and harms. Objective To determine the impact of school-based BMI reporting on weight status and adverse outcomes (weight stigmatization and weight-related perceptions and behaviors) among a diverse student population. Design, Setting, and Participants Cluster randomized clinical trial. The Fit Study (2014-2017) randomized 79 California schools to BMI screening and reporting (group 1), BMI screening only (group 2), or control (no BMI screening or reporting [group 3]) in grades 3 to 8. The setting was California elementary and middle schools. Students in grades 3 to 7 at baseline participated for up to 3 years. A modified intent-to-treat protocol was used. Data analysis was conducted from April 13, 2017, to March 26, 2020. Interventions School staff assessed BMI each spring among students in groups 1 and 2. Parents of students in group 1 were sent a BMI report each fall for up to 2 years. Main Outcomes and Measures Changes in BMIzscore and in adverse outcomes (based on surveys conducted each fall among students in grades 4 to 8) from baseline to 1 and 2 years of follow-up. Results A total of 28 641 students (14 645 [51.1%] male) in grades 3 to 7 at baseline participated in the study for up to 3 years. Among 6534 of 16 622 students with a baseline BMI in the 85th percentile or higher (39.3%), BMI reporting had no effect on BMIzscore change (−0.003; 95% CI, −0.02 to 0.01 at 1 year and 0.01; 95% CI, −0.02 to 0.03 at 2 years). Weight dissatisfaction increased more among students having BMI screened at school (8694 students in groups 1 and 2) than among control participants (5674 students in group 3). Results of the effect of BMI reporting on other adverse outcomes were mixed: compared with the control (group 3), among students weighed at school (groups 1 and 2), weight satisfaction declined more after 2 years (−0.11; 95% CI, −0.18 to −0.05), and peer weight talk increased more after 1 year (0.05; 95% CI, 0.01-0.09); however, concerning weight control behaviors declined more after 1 year (−0.06; 95% CI, −0.10 to −0.02). Conclusions and Relevance Body mass index reports alone do not improve children’s weight status and may decrease weight satisfaction. To improve student health, schools should consider investing resources in evidence-based interventions. Trial Registration ClinicalTrials.gov Identifier:NCT02088086
Fokker–Planck description of wealth dynamics and the origin of Pareto's law

The so-called "Yard-Sale Model" of wealth distribution posits that wealth is transferred between economic agents as a result of transactions whose size is proportional to the wealth of the less wealthy agent. In recent work [B. M. Boghosian, Phys. Rev. E89, 042804 (2014)], it was shown that this results in a Fokker–Planck equation governing the distribution of wealth. With the addition of a mechanism for wealth redistribution, it was further shown that this model results in stationary wealth distributions that are very similar in form to Pareto's well-known law. In this paper, a much simpler derivation of that Fokker–Planck equation is presented.
Shimura curves of genus at most two

We enumerate all Shimura curves X D 0 (R) of genus at most two: there are exactly 858 such curves, up to equivalence.
Co-orbital Asteroids as the Source of Venus's Zodiacal Dust Ring

Photometry from the Helios and STEREO spacecraft revealed regions of enhanced sky surface-brightness suggesting a narrow circumsolar ring of dust associated with Venus's orbit. We model this phenomenon by integrating the orbits of 10,000,000+ dust particles subject to gravitational and non-gravitational forces, considering several different kinds of plausible dust sources. We find that only particles from a hypothetical population of Venus co-orbital asteroids can produce enough signal in a narrow ring to match the observations. Previous works had suggested such objects would be dynamically unstable. However, we re-examined the stability of asteroids in 1:1 resonance with Venus and found that ~8% should survive for the age of the solar system, enough to supply the observed ring.
Electronic Structure and Optical Absorption of Fluorographene

A first-principles study on the quasiparticles energy and optical absorption spectrum of fluorographene is presented by employing the GW + Bethe-Salpeter Equation (BSE) method with many-electron effects included. The calculated band gap is increased from 3.0 eV to 7.3 eV by the GW approximation. Moreover, the optical absorption spectrum of fluorographene is dominated by enhanced excitonic effects. The prominent absorption peak is dictated by bright resonant excitons around 9.0 eV that exhibit a strong charge transfer character, shedding light on the exciton condensation and relevant optoelectronic applications. At the same time, the lowest-lying exciton at 3.8 eV with a binding energy of 3.5 eV is identified, which gives rise to explanation of the recent ultraviolet photoluminescence experiment.
Rank functions on rooted tree quivers

The free abelian group R(Q) on the set of indecomposable representations of a quiver Q, over a field K, has a ring structure where the multiplication is given by the tensor product. We show that if Q is a rooted tree (an oriented tree with a unique sink), then the ring R(Q)red is a finitely generated Z-module (here R(Q)red is the ring R(Q) modulo the ideal of all nilpotent elements). We describe the ring R(Q)red explicitly by studying functors from the category rep(Q) of representations of Q over K to the category of finite-dimensional K-vector spaces
Categories of dimension zero

If D is a category and k is a commutative ring, the functors from D to k-Mod can be thought of as representations of D. By definition, D is dimension zero over k if its finitely generated representations have finite length. We characterize categories of dimension zero in terms of the existence of a "homological modulus" (Definition 1.4) which is combinatorial and linear-algebraic in nature.
A Classification-based Approach for Approximate Reachability

Hamilton-Jacobi (HJ) reachability analysis has been developed over the past decades into a widely-applicable tool for determining goal satisfaction and safety verification in nonlinear systems. While HJ reachability can be formulated very generally, computational complexity can be a serious impediment for many systems of practical interest. Much prior work has been devoted to computing approximate solutions to large reachability problems, yet many of these methods may only apply to very restrictive problem classes, do not generate controllers, and/or can be extremely conservative. In this paper, we present a new method for approximating the optimal controller of the HJ reachability problem for control-affine systems. While also a specific problem class, many dynamical systems of interest are, or can be well approximated, by control-affine models. We explicitly avoid storing a representation of the reachability value function, and instead learn a controller as a sequence of simple binary classifiers. We compare our approach to existing grid-based methodologies in HJ reachability and demonstrate its utility on several examples, including a physical quadrotor navigation task.
Mapping variable ring polymer molecular dynamics: A path-integral based method for nonadiabatic processes

We introduce mapping-variable ring polymer molecular dynamics (MV-RPMD), a model dynamics for the direct simulation of multi-electron processes. An extension of the RPMD idea, this method is based on an exact, imaginary time path-integral representation of the quantum Boltzmann operator using continuous Cartesian variables for both electronic states and nuclear degrees of freedom. We demonstrate the accuracy of the MV-RPMD approach in calculations of real-time, thermal correlation functions for a range of two-state single-mode model systems with different coupling strengths and asymmetries. Further, we show that the ensemble of classical trajectories employed in these simulations preserves the Boltzmann distribution and provides a direct probe into real-time coupling between electronic state transitions and nuclear dynamics.
Translational symmetry and microscopic constraints on symmetry-enriched topological phases: A view from the surface

Researchers show that momentum of particles in some exotic crystalline phases of matter can become fractionalized compared to that of a single particle, and they lay out a way to connect this phenomenon with bulk properties of the crystal.
Order and disorder in irreversible decay processes.

Dynamical disorder motivates fluctuating rate coefficients in phenomenological, mass-action rate equations. The reaction order in these rate equations is the fixed exponent controlling the dependence of the rate on the number of species. Here, we clarify the relationship between these notions of (dis)order in irreversible decay, n A → B, n = 1, 2, 3, …, by extending a theoretical measure of fluctuations in the rate coefficient. The measure, Jn−Ln2≥0, is the magnitude of the inequality between Jn, the time-integrated square of the rate coefficient multiplied by the time interval of interest, and Ln2, the square of the time-integrated rate coefficient. Applying the inequality to empirical models for non-exponential relaxation, we demonstrate that it quantifies the cumulative deviation in a rate coefficient from a constant, and so the degree of dynamical disorder. The equality is a bound satisfied by traditional kinetics where a single rate constant is sufficient. For these models, we show how increasing the...
On the Importance of Nonlinear Modeling in Computer Performance Prediction

Computers are nonlinear dynamical systems that exhibit complex and sometimes even chaotic behavior. The low-level performance models used in the computer systems community, however, are linear. This paper is an exploration of that disconnect: when linear models are adequate for predicting computer performance and when they are not. Specifically, we build linear and nonlinear models of the processor load of an Intel i7-based computer as it executes a range of different programs. We then use those models to predict the processor loads forward in time and compare those forecasts to the true continuations of the time series.
The Temporal Changes in the Emission Spectrum of Comet 9p/Tempel 1 after Deep Impact

The time dependence of the changes in the emission spectra of Comet 9P/Tempel 1 after Deep Impact is derived and discussed. This was a unique event because for the first time it gave astronomers the opportunity to follow the time history of the formation and decay of O(1S), OH, CN, C2, C3, NH, and NH2. Least-squares fits of a modified Haser model with constraints using known rate constants were fit to the observed data. In the case of OH, a simple two-step Haser model provides a reasonable fit to the observations. Fitting the emissions from O(1S), CN, C2, C3, NH, and NH2 requires the addition of a delayed component to a regular two- or three-step Haser model. From this information, a picture of the Deep Impact encounter emerges where there is an initial formation of gas and dust, which is responsible for the prompt emission that occurs right after impact. A secondary source of gas starts later after impact when the initial dust has dissipated enough so that solar radiation can reach the surface of freshly exposed material. The implications of this and other results are discussed in terms of the structure and composition of the comet's nucleus.
A Mathematical Theory of Fame

We study empirically how the fame of WWI fighter-pilot aces, measured in numbers of web pages mentioning them, is related to their achievement, measured in numbers of opponent aircraft destroyed. We find that on the average fame grows exponentially with achievement; the correlation coefficient between achievement and the logarithm of fame is 0.72. The number of people with a particular level of achievement decreases exponentially with the level, leading to a power-law distribution of fame. We propose a stochastic model that can explain the exponential growth of fame with achievement. Next, we hypothesize that the same functional relation between achievement and fame that we found for the aces holds for other professions. This allows us to estimate achievement for professions where an unquestionable and universally accepted measure of achievement does not exist. We apply the method to Nobel Prize winners in Physics. For example, we obtain that Paul Dirac, who is a hundred times less famous than Einstein contributed to physics only two times less. We compare our results with Landau’s ranking.
Hyperbolicity, shadowing directions and sensitivity analysis of a turbulent three-dimensional flow

This paper uses compressible flow simulation to analyse the hyperbolicity, shadowing directions and sensitivities of a weakly turbulent three-dimensional cylinder flow at Reynolds number 525 and Mach number 0.1. By computing the first 40 covariant Lyapunov vectors (CLVs), we find that unstable CLVs are active in the near-wake region, whereas stable CLVs are active in the far-wake region. This phenomenon is related to hyperbolicity since it shows that CLVs point to different directions; it also suggests that for open flows there is a large fraction of CLVs that are stable. However, due to the extra neutral CLV and the occasional tangencies between CLVs, our system is not uniform hyperbolic. By the non-intrusive least-squares shadowing (NILSS) algorithm, we compute shadowing directions and sensitivities of long-time-averaged objectives. Our results suggest that shadowing methods may be valid for general chaotic fluid problems.
Deterministic, Stash-Free Write-Only ORAM

Write-Only Oblivious RAM (WoORAM) protocols provide privacy by encrypting the contents of data and also hiding the pattern of write operations over that data. WoORAMs provide better privacy than plain encryption and better performance than more general ORAM schemes (which hide both writing and reading access patterns), and the write-oblivious setting has been applied to important applications of cloud storage synchronization and encrypted hidden volumes. In this paper, we introduce an entirely new technique for Write-Only ORAM, called DetWoORAM. Unlike previous solutions, DetWoORAM uses a deterministic, sequential writing pattern without the need for any "stashing" of blocks in local state when writes fail. Our protocol, while conceptually simple, provides substantial improvement over prior solutions, both asymptotically and experimentally. In particular, under typical settings the DetWoORAM writes only 2 blocks (sequentially) to backend memory for each block written to the device, which is optimal. We have implemented our solution using the BUSE (block device in user-space) module and tested DetWoORAM against both an encryption only baseline of dm-crypt and prior, randomized WoORAM solutions, measuring only a 3x-14x slowdown compared to an encryption-only baseline and around 6x-19x speedup compared to prior work.
Rotating drops with helicoidal symmetry

See this http URL for a YouTube video showing part of the results in this paper. We consider helicoidal immersions in the Euclidean space whose axis of symmetry is the z-axis that are solutions of the equation 2 H=\Lambda_0-a 1/2 R^2 where H is the mean curvature of the surface, R is the distance form the point in the surface to the z-axis and a is a real number. We refer to these surfaces as helicoidal rotating drops. We prove the existence of properly immersed solutions that contain the z-axis. We also show the existence of several families of embedded examples. We describe the set of possible solutions and we show that most of these solutions are not properly immerse and are dense in the region bounded by two concentric cylinders. We show that all properly immersed solutions, besides being invariant under a one parameter helicoidal group, they are invariant under a cyclic group of rotations of the variables x and y. The second variation of energy for the volume constrained problem with Dirichlet boundary conditions is also studied.
The quest for solvable multistate Landau-Zener models

Recently, integrability conditions (ICs) in mutistate Landau-Zener (MLZ) theory were proposed [1]. They describe common properties of all known solved systems with linearly time-dependent Hamiltonians. Here we show that ICs enable efficient computer assisted search for new solvable MLZ models that span complexity range from several interacting states to mesoscopic systems with many-body dynamics and combinatorially large phase space. This diversity suggests that nontrivial solvable MLZ models are numerous. In addition, we refine the formulation of ICs and extend the class of solvable systems to models with points of multiple diabatic level crossing.
Correlation lengths in quasi-one-dimensional systems via transfer matrices

Using transfer matrices up to next-nearest-neighbour interactions, we examine the structural correlations of quasi-one-dimensional systems of hard disks confined by two parallel lines and hard sphe...
Tensor-Scalar Torsion

A theory of gravity with torsion is examined in which the torsion tensor is constructed from the exterior derivative of an antisymmetric rank-two potential plus the dual of the gradient of a scalar field. Field equations for the theory are derived by demanding that the action be stationary under variations with respect to the metric, the antisymmetric potential, and the scalar field. A material action is introduced and the equations of motion are derived. The correct conservation law for rotational angular momentum plus spin is observed to hold in this theory.
Accreting Black Hole Binaries in Globular Clusters

We explore the formation of mass-transferring binary systems containing black holes within globular clusters. We show that it is possible to form mass-transferring black hole binaries with main sequence, giant, and white dwarf companions with a variety of orbital parameters in globular clusters spanning a large range in present-day properties. All mass-transferring black hole binaries found in our models at late times are dynamically created. The black holes in these systems experienced a median of $\sim 30$ dynamical encounters within the cluster before and after acquiring the donor. Furthermore, we show that the presence of mass-transferring black hole systems has little correlation with the total number of black holes within the cluster at any time. This is because the net rate of formation of black hole-non-black hole binaries in a cluster is largely independent of the total number of retained black holes. Our results suggest that the detection of a mass-transferring black hole binary in a globular cluster does not necessarily indicate that the host cluster contains a large black hole population.