cssi/SciSciGPT-SciSciNet huggingface dataset:
The Lucas Orchard

This paper investigates the behavior of asset prices in an endowment economy in which a representative agent with power utility consumes the dividends of multiple assets. The assets are Lucas trees; a collection of Lucas trees is a Lucas orchard. The model generates return correlations that vary endogenously, spiking at times of disaster. Since disasters spread across assets, the model generates large risk premia even for assets with stable cashflows. Very small assets may comove endogenously and hence earn positive risk premia even if their cashflows are independent of the rest of the economy. I provide conditions under which the variation in a small asset's price-dividend ratio can be attributed almost entirely to variation in its risk premium.
Generic time- and method-interdependencies of empirical impact-measurements: A generalizable model of adaptation-processes of carsharing-users' mobility-behavior over time

The purpose of this article is to advance empirical sustainability-evaluations of carsharing-systems. Carsharing, a frequently cited example of a product–service system (PSS), is currently morphing from a niche into a mainstream mode of transportation. Carsharing has the potential to provide a more sustainable mobility-option compared to private car usage, for example by reducing the overall motor-vehicle traffic in cities. However, the quantification of this potential is complex, and few studies have analyzed the fundamental impacts of the chosen measurement-methodology on the results of empirical carsharing-evaluations. This article analyses the time- and method-interdependencies of carsharing-studies based on a generic model structuring the adaptation of the mobility-behavior of carsharing-users over time. A paradigm shift from a static to a dynamic view on impacts of the PSS carsharing is proposed, which could support policymakers enacting carsharing-regulations in cities. The analysis of generic methodological interdependencies when conceptualizing impacts as dynamic processes is generalizable to impact-assessments of new technologies changing user-behavior over time.
Analyzing Discourse Structure to Coordinate Educational Forums

In this paper, aspects related to discourse structure like message chaining, message date and categorization are used by teachers to coordinate educational forums in the AulaNet environment. These aspects can be computationally analyzed without having to inspect the content of each message. This analysis could be applied to forums in other educational environments.
A menu-driven software package of Bayesian nonparametric (and parametric) mixed models for regression analysis and density estimation.

Most of applied statistics involves regression analysis of data. In practice, it is important to specify a regression model that has minimal assumptions which are not violated by data, to ensure that statistical inferences from the model are informative and not misleading. This paper presents a stand-alone and menu-driven software package, Bayesian Regression: Nonparametric and Parametric Models, constructed from MATLAB Compiler. Currently, this package gives the user a choice from 83 Bayesian models for data analysis. They include 47 Bayesian nonparametric (BNP) infinite-mixture regression models; 5 BNP infinite-mixture models for density estimation; and 31 normal random effects models (HLMs), including normal linear models. Each of the 78 regression models handles either a continuous, binary, or ordinal dependent variable, and can handle multi-level (grouped) data. All 83 Bayesian models can handle the analysis of weighted observations (e.g., for meta-analysis), and the analysis of left-censored, right-censored, and/or interval-censored data. Each BNP infinite-mixture model has a mixture distribution assigned one of various BNP prior distributions, including priors defined by either the Dirichlet process, Pitman-Yor process (including the normalized stable process), beta (two-parameter) process, normalized inverse-Gaussian process, geometric weights prior, dependent Dirichlet process, or the dependent infinite-probits prior. The software user can mouse-click to select a Bayesian model and perform data analysis via Markov chain Monte Carlo (MCMC) sampling. After the sampling completes, the software automatically opens text output that reports MCMC-based estimates of the model’s posterior distribution and model predictive fit to the data. Additional text and/or graphical output can be generated by mouse-clicking other menu options. This includes output of MCMC convergence analyses, and estimates of the model’s posterior predictive distribution, for selected functionals and values of covariates. The software is illustrated through the BNP regression analysis of real data.
Extending the domain of validity of the Lagrangian approximation

We investigate convergence of Lagrangian perturbation theory (LPT) by analysing the model problem of a spherical homogeneous top hat in an Einstein–de Sitter background cosmology. We derive the formal structure of the LPT series expansion, working to arbitrary order in the initial perturbation amplitude. The factors that regulate LPT convergence are identified by studying the exact, analytic solution expanded according to this formal structure. The key methodology is to complexify the exact solution, demonstrate that it is analytic and apply well-known convergence criteria for power series expansions of analytic functions. The ‘radius of convergence’ and the ‘time of validity’ for the LPT expansion are of great practical interest. The former describes the range of initial perturbation amplitudes which converge over some fixed, future time interval. The latter describes the extent in time for convergence of a given initial amplitude. We determine the radius of convergence and time of validity for a full sampling of initial density and velocity perturbations. This analysis fully explains the previously reported observation that LPT fails to predict the evolution of an underdense, open region beyond a certain time. It also implies the existence of other examples, including overdense, closed regions, for which LPT predictions should also fail. We show that this is indeed the case by numerically computing the LPT expansion in these problematic cases. The formal limitations to the validity of LPT expansion are considerably more complicated than simply the first occurrence of orbit crossings as is often assumed. Evolution to a future time generically requires re-expanding the solution in overlapping domains that ultimately link the initial and final times, each domain subject to its own time of validity criterion. We demonstrate that it is possible to handle all the problematic cases by taking multiple steps (LPT re-expansion). A relatively small number (∼10) of re-expansion steps suffices to satisfy the time of validity constraints for calculating the evolution of a non-collapsed, recombination-era perturbation up to the current epoch. If it were possible to work to infinite Lagrangian order then the result would be exact. Instead, a finite expansion has finite errors. We characterize how the leading order numerical error for a solution generated by LPT re-expansion varies with the choice of Lagrangian order and of time-step size. Convergence occurs when the Lagrangian order increases and/or the time-step size decreases in a simple, well-defined manner. We develop a recipe for time-step control for LPT re-expansion based on these results.
Good and bad uncertainty: Macroeconomic and financial market implications ☆

Does macroeconomic uncertainty increase or decrease aggregate growth and asset prices? To address question, we decompose aggregate uncertainty of macroeconomic data into ‘good’ and ‘bad’ uncertainty components, which correspond respectively to the volatility associated with positive and negative innovations to macroeconomic growth rates. We document that in line with our theoretical framework, these two types of uncertainty have dierent impact on the macroeconomy and asset prices. Good uncertainty predicts an increase in future economic activity, such as consumption, output, and investment, and is positively related to valuation ratios, while bad uncertainty forecasts a decline in economic growth and depresses asset prices. Further, we show that the market price of risk and equity beta to good uncertainty shocks are positive, while they are negative to bad uncertainty shocks. Hence, both good and bad uncertainty risks contribute positively to equity risk premia and help explain the cross section of expected returns beyond cash ow risk.
Toward a collection-based metadata maintenance model

In this paper, the authors identify key entities and relationships in the operational management of metadata catalogs that describe digital collections, and they draft a data model to support the administration of metadata maintenance for collections. Further, they consider this proposed model in light of other data schemes to which it relates and discuss the implications of the model for library metadata maintenance operations.
Institutional convergence: exit or voice?

There is a small but growing literature on the determinants of economic freedom. This paper contributes to this literature in two ways. First, it is empirically shown that β-convergence in economic freedom occurred from 1980 to 2010. Countries with low levels of economic freedom in 1980 “catch up” at a rate of 0.7 percent a year on average, ceteris paribus. Second, the structural characteristics that contribute to this institutional convergence are documented. Conditional convergence estimates suggest democratic institutions do not con- tribute to conditional convergence. Exitability, a variable that captures how easy it is for citizens to “vote with their feet” is related to the change in economic freedom from 1980 to 2010 in a statistically significant manner across all specifications. This provides some preliminary evidence as to the importance of “exit” versus “voice” with respect to the question of institutional change.
Dimethylamine as a major alkyl amine species in particles and cloud water: Observations in semi-arid and coastal regions.

Abstract Aerosol and cloud water measurements of dimethylamine (DMA), the most abundant amine in this study, were conducted in semi-arid (Tucson, Arizona) and marine (Nucleation in California Experiment, NiCE; central coast of California) areas. In both regions, DMA exhibits a unimodal aerosol mass size distribution with a dominant peak between 0.18 and 0.56 μm. Particulate DMA concentrations increase as a function of marine biogenic emissions, sulfate, BVOC emissions, and aerosol-phase water. Such data supports biogenic sources of DMA, aminium salt formation, and partitioning of DMA to condensed phases. DMA concentrations exhibit positive correlations with various trace elements and most especially vanadium, which warrants additional investigation. Cloud water DMA levels are enhanced significantly during wildfire periods unlike particulate DMA levels, including in droplet residual particles, due to effective dissolution of DMA into cloud water and probably DMA volatilization after drop evaporation. DMA: NH 4 + molar ratios peak between 0.18 and 1.0 μm depending on the site and time of year, suggesting that DMA competes better with NH3 in those sizes in terms of reactive uptake by particles.
Expanders via local edge flips

Designing distributed and scalable algorithms to improve network connectivity is a central topic in peer-to-peer networks. In this paper we focus on the following well-known problem: given an n-node d-regular network for d = Ω(log n), we want to design a decentralized, local algorithm that transforms the graph into one that has good connectivity properties (low diameter, expansion, etc.) without affecting the sparsity of the graph. To this end, Mahlmann and Schindelhauer introduced the random "flip" transformation, where in each time step, a random pair of vertices that have an edge decide to 'swap a neighbor'. They conjectured that performing O(nd) such flips at random would convert any connected d-regular graph into a d-regular expander graph, with high probability. However, the best known upper bound for the number of steps is roughly O(n17d23), obtained via a delicate Markov chain comparison argument.Our main result is to prove that a natural instantiation of the random flip produces an expander in at most O(n2d2[EQUATION] n) steps, with high probability. Our argument uses a potential-function analysis based on the matrix exponential, together with the recent beautiful results on the higher-order Cheeger inequality of graphs. We also show that our technique can be used to analyze another well-studied random process known as the 'random switch', and show that it produces an expander in O(nd) steps with high probability.
High-frequency and high-quality silicon carbide optomechanical microresonators

Silicon carbide (SiC) exhibits excellent material properties attractive for broad applications. We demonstrate the first SiC optomechanical microresonators that integrate high mechanical frequency, high mechanical quality, and high optical quality into a single device. The radial-breathing mechanical mode has a mechanical frequency up to 1.69 GHz with a mechanical Q around 5500 in atmosphere, which corresponds to a fm · Qm product as high as 9.47 × 10(12) Hz. The strong optomechanical coupling allows us to efficiently excite and probe the coherent mechanical oscillation by optical waves. The demonstrated devices, in combination with the superior thermal property, chemical inertness, and defect characteristics of SiC, show great potential for applications in metrology, sensing, and quantum photonics, particularly in harsh environments that are challenging for other device platforms.
Intergalactic filaments as isothermal gas cylinders

Using a cosmological simulation at redshift 5, we find that the baryon-rich cores of intergalactic filaments extending outwards from galaxies commonly form isothermal gas cylinders in regions favourable to their formation. The central gas density is typically about 500 times the cosmic mean total density, and the temperature is typically 1–2 × 104 K, just above the Lyman α cooling floor. These findings argue that the hydrodynamic properties of the gas are more important than the dark matter in determining this structure. It is noteworthy that the temperature and ionization state of the gas completely determine a finite total mass per unit length of an isothermal cylinder. Our findings may have implications for understanding the ‘cold-mode’ mechanism of gas transport into galaxies.
Hedge Fund Diversification: How Much Is Enough?

There are many benefits to investing in hedge funds, particularly when using a diversified multi-strategy approach. Over recent years, multi-strategy funds of hedge funds have flourished and are now the favorite investment vehicle of institutional investors exploring the world of alternative investments. More recently, funds of hedge funds that specialize within an investment style have also emerged. The authors study the impact of diversification on naively constructed (randomly chosen and equally weighted) hedge fund portfolios. They provide insight into style diversification benefits as well as the inter-temporal evolution of diversification effects on hedge funds.
Generalizations of Ceva's Theorem and Applications

Analytical proof: Let M be a point in the plain of the triangle ABC , such that it satisfies the conditions of the theorem. One chooses a Cartesian system of axes, such that the two parallels with the axes which pass through M do not pass by any point Ai (this is possible). One considers M (a,b) , where a and b are real variables, and Ai (Xi ,Yi ) where Xi and Yi are known, i ∈ 1,2,...,n { }. The former choices ensure us the following relations: Xi − a ≠ 0 and 0 i Y b − ≠ for all i ∈ 1,2,...,n { }. The equation of the line (1 ) i A M i n ≤ ≤ is: x − a Xi − a − y − b Yi − b = 0. One notes that d(x, y; Xi ,Yi ) = 0 .
ComTrustO: Composite trust-based ontology framework for information and decision fusion

Interactions between humans and machines are often placed in a multi-layered network involving the multidimensional trust in communication, information, and socio-cognitive layers. In this complex environment, how to filter and fuse heterogeneous data is critical for effective decision making. In this work, we propose an ontology-based framework for information fusion, as a support system for human decision makers. In particular, we build upon the concept of composite trust, consisting of four trust types: communication trust, information trust, social trust, and cognitive trust. Based on the concept of multidimensional trust, we construct a composite trust ontology framework, called ComTrustO, that embraces four trust ontologies, one for each trust type. We present the details of the integrated ontology framework and discuss a concrete example scenario.
Understanding image virality

Virality of online content on social networking websites is an important but esoteric phenomenon often studied in fields like marketing, psychology and data mining. In this paper we study viral images from a computer vision perspective. We introduce three new image datasets from Reddit1 and define a virality score using Reddit metadata. We train classifiers with state-of-the-art image features to predict virality of individual images, relative virality in pairs of images, and the dominant topic of a viral image. We also compare machine performance to human performance on these tasks. We find that computers perform poorly with low level features, and high level information is critical for predicting virality. We encode semantic information through relative attributes. We identify the 5 key visual attributes that correlate with virality. We create an attribute-based characterization of images that can predict relative virality with 68.10% accuracy (SVM+Deep Relative Attributes) -better than humans at 60.12%. Finally, we study how human prediction of image virality varies with different “contexts” in which the images are viewed, such as the influence of neighbouring images, images recently viewed, as well as the image title or caption. This work is a first step in understanding the complex but important phenomenon of image virality. Our datasets and annotations will be made publicly available.
The Predictability of Equity REIT Returns

This study examines the predictability of monthly returns on equity real estate investment trusts (EREITs) over the period 1975-95 and compares it with that for small-and mid-cap firms. Using the t...
Parents, peers, or school inputs: Which components of school outcomes are capitalized into house value?

Abstract Previous research has established that people bid more for houses in high-performing school districts. But what specific factors related to school outcomes influence house prices: the parents, the peers, or the school inputs? We study the extent that house values are affected by each of the components of an education production function. Based on 123 school districts and 26,000 house transactions, we find that parental inputs are the primary component of school outcomes that are capitalized into house prices. In the explanation of variations in house prices, variations in parental characteristics are at least seven times more important than similar variations in the influence of peer groups. We find no influence on house prices from variations in school inputs. This result suggests that land values in a particular community will be increased more by attention to zoning laws that influence the mix of renters to homeowners and the type of households entering a community compared to investing in additional public school inputs.
Catalysis: Dual catalysis at the flick of a switch

A combination of two catalysts — one of which is light-activated — has been used to promote new chemical reactivity, opening up fresh opportunities for the synthesis of structurally complex organic molecules. See Letter p.74 James Cuthbertson and David MacMillan describe the development of a new and general strategy for the direct arylation of allylic sp3 C–H bonds, potentially providing a strategy for the construction of complex organic molecules via the coupling of simple and otherwise inert building blocks, without introducing extraneous functional groups. The process, combing photoredox and thiol-based organic catalysis, requires only under mild conditions; and can accommodate a wide range of alkene and electron-deficient arene coupling partners.
Heavy quarkonia in quark-gluon plasma

Using the color-singlet free energy ${F}_{1}$ and total internal energy ${U}_{1}$ obtained by Kaczmarek et al. (hep-lat/0309121) for a static quark Q and an antiquark $\overline{Q}$ in quenched QCD, we study the binding energies and wave functions of heavy quarkonia in a quark-gluon plasma. By minimizing the grand potential in a simplified schematic model, we find that the proper color-singlet $Q\text{\ensuremath{-}}\overline{Q}$ potential can be obtained from the total internal energy ${U}_{1}$ by subtracting the gluon internal energy contributions. We carry out this subtraction in the local energy-density approximation in which the gluon energy density can be related to the local gluon pressure by the quark-gluon plasma equation of state. We find in this approximation that the proper color-singlet $Q\text{\ensuremath{-}}\overline{Q}$ potential is approximately ${F}_{1}$ for $T~{T}_{c}$ and it changes to $\frac{3}{4}{F}_{1}+\frac{1}{4}{U}_{1}$ at high temperatures. In this potential model, the $J/\ensuremath{\psi}$ is weakly bound above the phase-transition temperature ${T}_{c}$, and it dissociates spontaneously above $1.62{T}_{c}$, whereas ${\ensuremath{\chi}}_{c}$ and ${\ensuremath{\psi}}^{'}$ are unbound in the quark-gluon plasma. The bottomium states $\ensuremath{\Upsilon},{\ensuremath{\chi}}_{b}$, and ${\ensuremath{\Upsilon}}^{'}$ are bound in the quark-gluon plasma and they dissociate at $4.1{T}_{c},1.18{T}_{c},$ and $1.38{T}_{c}$ respectively. For comparison, we evaluate the heavy quarkonium binding energies also in other models using the free energy ${F}_{1}$ or the total internal energy ${U}_{1}$ as the $Q\text{\ensuremath{-}}\overline{Q}$ potential. The comparison shows that the model with the new $Q\text{\ensuremath{-}}\overline{Q}$ potential proposed here gives dissociation temperatures that agree best with those from spectral function analyses. We evaluate the cross section for $\ensuremath{\sigma}(g+J/\ensuremath{\psi}\ensuremath{\rightarrow}c+\overline{c})$ and its inverse process to determine the $J/\ensuremath{\psi}$ dissociation width and the rate of $J/\ensuremath{\psi}$ production by recombining c and $\overline{c}$ in the quark-gluon plasma.
Inclusive CP asymmetries in semileptonic decays of B mesons

We estimate the sensitivity of single lepton CP violation measurements with respect to that of traditional dilepton measurements. We find that the sensitivity of the single lepton method is better than that of the di-lepton method. The achievable sensitivity with the currently available data is already in the range relevant to standard model predictions. We also give general expressions for inclusive decay time distributions on ϒ4S where the other B is not measured, which will be used to obtain time dependent asymmetries. The expression is of general use whenever one deals with inclusive time-dependent as well as time-integrated measurements in ϒ(4S) → B0B0 where the final state of the other B is not reconstructed or when only the time difference is measured.
Strong-Field General Relativity and Quasi-periodic Oscillations in X-Ray Binaries

Quasi-periodic oscillations (QPOs) at frequencies near 1000 Hz were recently discovered in several X-ray binaries containing neutron stars. Two sources show no correlation between QPO frequency and source count rate. We suggest that the QPO frequency is determined by the Keplerian orbital frequency near the marginally stable orbit predicted by general relativity in strong gravitational fields. The radius of the marginally stable orbit does not depend on the luminosity or mass accretion rate of the source; therefore the QPO frequency does not depend on the source count rate. The QPO frequencies observed from 4U 1636-536 imply that the mass of the neutron star is 2.02 ± 0.12 M☉. Interpretation of the 4.1 keV absorption line observed from 4U 1636-536 as due to Fe XXV ions then implies a neutron star radius of 9.6 ± 0.6 km.
X-ray emission from clusters of galaxies

Some X-ray spectral observations of approximately 30 clusters of galaxies from HEAO-1 are summarized. There exists strong correlation betwen X-ray luminosity, L(x), and temperature kT in the form L(x)alphaT to the 2.3 power. This result combined with the L(x) central galaxy density relation and the virial theorem indicates that the core dadius of the gas should be roughly independent of L(x) or Kt and that more luminous clusters have a greater fraction of their virial mass in gas. The poor correlation of KT and optical velocity dispersion seems to indicate that clusters have a variety of equations of state. There is poor agreement between X-ray imaging observations and optical and X-ray spectral measures of the polytropic index. Most clusters show Fe emission lines with a strong indication that they all have roughly 1/2 solar abundance. The evidence for cooling in the cores several clusters is discussed based on spectral observations with the Einstein solid state spectrometer.
Water on the Moon

THE possibility that water has existed on the Moon for varying lengths of time, both in liquid arid in solid form, and both beneath the surface and on the surface, has been widely discussed during the past 10 years1–7. The subject has been discussed repeatedly at scientific meetings and has been received mostly with great scepticism. Evidence supporting this view has recently become quite overwhelming and, in fact, no communication seems necessary to point out the evidence from the Orbiter 4 and 5 pictures8. Because many people are not aware of this evidence and suggest that the effects are caused by other liquids, that is, lava, dust-gas or possibly even vodka, a brief discussion of the evidence may be in order.
An intramolecular, Schmidt reaction of an alkyl azide with a carbocation. The generation and rearrangement of a conformationally restricted secondary aminodiazonium ion.

Abstract Treatment of azidoalkene2 with triflic acid produced the bridged bicyclic enamine3 by an intramolecular Schmidt reaction. Rearrangement of the intermediate aminodiazonium ion5 is completely regioselective.
The Effects of Thermal Conduction on Radiatively Inefficient Accretion Flows

We quantify the effects of electron thermal conduction on the properties of hot accretion flows, under the assumption of spherical symmetry. Electron heat conduction is important for low accretion rate systems where the electron cooling time is longer than the conduction time of the plasma, such as Sgr A* in the Galactic center. For accretion flows with density profiles similar to the Bondi solution [n(r) ∝ r-3/2], we show that heat conduction leads to supervirial temperatures, implying that conduction significantly modifies the dynamics of the accretion flow. We then self-consistently solve for the dynamics of spherical accretion in the presence of saturated conduction and electron heating. We find that the accretion rate onto the central object can be reduced by ~1-3 orders of magnitude relative to the canonical Bondi rate. Electron conduction may thus be an important ingredient in explaining the low radiative efficiencies and low accretion rates inferred from observations of low-luminosity galactic nuclei. The solutions presented in this paper may also describe the nonlinear saturation of the magnetothermal instability in hot accretion flows.
Invariant operators in collinear effective theory

Abstract We consider processes which produce final state hadrons whose energy is much greater than their mass. In this limit interactions involving collinear fermions and gluons are constrained by a symmetry, and we give a general set of rules for constructing leading and subleading invariant operators. Wilson coefficients C(μ, P ) are functions of a label operator P , and do not commute with collinear fields. The symmetry is used to reproduce a two-loop result for factorization in B → Dπ in a simple way.
Effects of Surface Pinning, Locking and Adaption of Twins on the Performance of Magnetic Shape-Memory Alloys

We study the effect of surface modifications and constraints on the mechanical properties of Ni-Mn- Ga single crystals, which are imposed by (i) structural modifications near the surface, (ii) mounting to a solid surface, and (iii) guiding the stroke. Spark eroded samples were electropolished and characterized before and after each polishing treatment. Surface damage was then produced with spark erosion and abrasive wearing. Surface damage stabilizes and pins a dense twin-microstructure and prevents twins from coarsening. The density of twins increases with increasing degree of surface deformation. Twinning stress and hardening rate during mechanical loading increase with increasing surface damage and twin density. In contrast, when a damaged surface layer is removed, twinning stresses, hardening rate, and twin density decrease. Constraining the sample by mounting and guiding reduces the magnetic-field-induced strain by locking twins at the constrained surfaces. . For single-domain crystals and for hard magnetic shape-memory alloys, external constraints strongly reduce the magnetic-field-induced strain and the fatigue lifetime is short. In contrast, for selfaccommodated martensite and for soft magnetic shape-memory alloys, the twin-microstructure adapts well to external constraints and the fatigue lifetime is long. The performance of devices with MSMA transducers requires managing stress distributions through design and control of surface properties, microstructure, and constraints.
Light photinos as dark matter.

There are good reasons to consider models of low-energy supersymmetry with very light photinos and gluinos. In most of these models the lightest $R$-odd, color-singlet state containing a gluino, the ${R}^{0}$, has a mass in the 1-2 GeV range and the slightly lighter photino $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\gamma}}$ would survive as the relic $R$-odd species. For the light photino masses considered here, previous calculations resulted in an unacceptable photino relic abundance. But we point out that processes other than photino self-annihilation determine the relic abundance when the photino and ${R}^{0}$ are close in mass. Including ${R}^{0}\ensuremath{\leftrightarrow}\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\gamma}}$ processes, we find that the photino relic abundance is most sensitive to the ${R}^{0}$-to-$\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\gamma}}$ mass ratio, and within model uncertainties, a critical density in photinos may be obtained for an ${R}^{0}$-to-$\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\gamma}}$ mass ratio in the range 1.2 to 2.2. We propose photinos in the mass range of 500 MeV to 1.6 GeV as a dark matter candidate, and discuss a strategy to test the hypothesis.
Current Resources for Evidence‐Based Practice September/October 2012

Screening Women for Intimate Partner Violence In a 2004 United States Preventive Services Task Force (USPSTF) report, researchers found insufficient evidence to support routine screening of women for intimate partner violence (IPV) (U.S. Preventive Services Task Force, 2004). More recent studies included in an updated Evidence Report have prompted important changes in recommendations (Nelson, Bougatsos, & Blazina, 2012). In this most recent update, five key questions guided the systematic review and were informed by 35 studies. The report demonstrated that the use of screening tools for IPV can accurately identify women experiencing IPV (fair to good quality evidence). While results varied by population and type of intervention (fair to good quality evidence), screening women for IPV was found to improve health outcomes by decreasing IPV. While some women may experience discomfort, loss of privacy, and concern about further abuse, in general, IPV screening was found to have minimal adverse effects (fair evidence). Results from this systematic review are congruent with recent recommendations from the Institute of Medicine’s 2011 report on Clinical Preventive Services for Women (National Research Council, 2011) that underscore the importance of screening women for IPV.
On the number of distinct functional graphs of affine-linear transformations over finite fields

Abstract We study the number of non-isomorphic functional graphs of affine-linear transformations from ( F q ) n to itself, and we prove upper and lower bounds on this quantity as n→∞. As a corollary to our result, we prove bounds on the number of conjugacy classes in the symmetric group S q n that intersect AGLn(q).
The Solar Connection of Enhanced Heavy Ion Charge States in the Interplanetary Medium: Implications for the Flux-Rope Structure of CMEs

We investigated a set of 54 interplanetary coronal mass ejection (ICME) events whose solar sources are very close to the disk center (within ± 15∘ from the central meridian). The ICMEs consisted of 23 magnetic-cloud (MC) events and 31 non-MC events. Our analyses suggest that the MC and non-MC ICMEs have more or less the same eruption characteristics at the Sun in terms of soft X-ray flares and CMEs. Both types have significant enhancements in ion charge states, although the non-MC structures have slightly lower levels of enhancement. The overall duration of charge-state enhancement is also considerably smaller than that in MCs as derived from solar wind plasma and magnetic signatures. We find very good correlation between the Fe and O charge-state measurements and the flare properties such as soft X-ray flare intensity and flare temperature for both MCs and non-MCs. These observations suggest that both MC and non-MC ICMEs are likely to have a flux-rope structure and the unfavorable observational geometry may be responsible for the appearance of non-MC structures at 1 AU. We do not find any evidence for an active region expansion resulting in ICMEs lacking a flux-rope structure because the mechanism of producing high charge states and the flux-rope structure at the Sun is the same for MC and non-MC events.
Algebraic Levi-Flat Hypervarieties in Complex Projective Space

We study singular real-analytic Levi-flat hypersurfaces in complex projective space. We define the rank of an algebraic Levi-flat hypersurface and study the connections between rank, degree, and the type and size of the singularity. In particular, we study degenerate singularities of algebraic Levi-flat hypersurfaces. We then give necessary and sufficient conditions for a Levi-flat hypersurface to be a pullback of a real-analytic curve in ℂ via a meromorphic function. Among other examples, we construct a nonalgebraic semianalytic Levi-flat hypersurface with compact leaves that is a perturbation of an algebraic Levi-flat variety.
Shape-adaptive discrete wavelet transform for coding arbitrarily shaped texture

This paper presents a shape adaptive discrete wavelet transform (SA-DWT) scheme for coding arbitrarily shaped texture. The proposed SA-DWT can be used for object-oriented image coding. The number of coefficients after SA-DWT is identical to the number of pels contained in the arbitrarily shaped image objects. The locality property of wavelet transform and self-similarity among subbands are well preserved throughout this process.For a rectangular region, the SA-DWT is identical to a standard wavelet transform. With SA-DWT, conventional wavelet based coding schemes can be readily extended to the coding of arbitrarily shaped objects. The proposed shape adaptive wavelet transform is not unitary but the small energy increase is restricted at the boundary of objects in subbands. Two approaches of using the SA-DWT algorithm for object-oriented image and video coding are presented. One is to combine scalar SA-DWT with embedded zerotree wavelet (EZW) coding technique, the other is an extension of the normal vector wavelet coding (VWC) technique to arbitrarily shaped objects. Results of applying SA-VWC to real arbitrarily shaped texture coding are also given at the end of this paper.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Very‐low‐pressure pyrolysis of ethylbenzene, isopropylbenzene, and tert‐butylbenzene

The thermal unimolecular decomposition of ethylbenzene, isopropylbenzene, and tert-butylbenzene was studied using the very-low-pressure pyrolysis (VLPP) technique. Each reactant decomposed by way of β CC bond homolysis, producing methyl radicals and benzyl or benzylic-type radicals. RRKM calculations show that the observed rate constants, when combined with thermochemical estimates, are consistent with the following high-pressure rate expressions: for ethylbenzene between 1053 and 1234 K, for isopropylbenzene between 971 and 1151 K, and for tert-butylbenzene between 929 and 1157 K, where θ (kcal/mol) = 2.303RT. Resulting activation energies combined with heat capacity and heat of formation data led to the following dissociation enthalpies and enthalpies of formation at 298 K: DH° (oCH(CH3)CH3) = 73.8 kcal/mol, ΔHf° (oCCH(CH3)) = 39.6 kcal/mol, DH° (oC(CH3)2CH3) = 72.9 kcal/mol, and ΔHf° (oC(CH3)2) = 32.4 kcal/mol. Derived high-pressure rate constants are in good accord with results of lower temperature toluene- and aniline-carrier experiments.
A Scheme Allowing Synthesis and Characterization of Ultrafast Waveforms Using Coherent Raman Sidebands

We propose a new scheme which allows synthesis and characterization of ultrafast waveforms using coherent Raman sidebands. We show that a deformable mirror may be used for fine phase adjustment.
Decaying particles do not "heat up" the Universe.

It is usually assumed that a massive relic species, which comes to dominate the mass density of the Universe and later decays, ``heats up'' the Universe when the age of the Universe \ensuremath{\simeq} its lifetime. We show that if its decay follows the usual exponential decay law, then the Universe is never reheated, rather it just cools more slowly. We calculate the evolution of the temperature and entropy, and find that to within numerical factors of order unity, the usual estimates for the entropy increase are correct. Our results have implications for primordial nucleosynthesis in scenarios where a massive relic with lifetime \ensuremath{\simeq} ${10}^{\mathrm{\ensuremath{-}}2}$--${10}^{3}$ sec is present, and for baryogenesis in the new inflationary Universe scenario.
Photodissociation of CO isotopologues: Models of laboratory experiments and implications for the solar nebula

CO photodissociation in the solar nebula and/or parent cloud has been proposed to be the mechanism responsible for forming the 16O-poor reservoir of the calcium-aluminum-rich inclusion (CAI) mixing line. However, laboratory experiments on CO photolysis found a wavelength dependence in the oxygen isotope ratios of the product O atoms, which was interpreted as proof that CO photolysis was not a viable mechanism. Here, I report photochemical simulations of these experiments using line-by-line CO spectra to identify the origin of the wavelength dependence. At long wavelengths (>105 nm), the line-by-line spectra for isotopic CO can explain the experimental data with a combination of C16O self-shielding and reduced dissociation probabilities for C18O. At short wavelengths, the greater number of diffuse bands increases the importance of mass-dependent fractionation, lowering the slope to below unity. The line-by-line isotopic spectra are then applied to CO photodissociation in a model solar nebula. Three FUV sources are considered (1) HD 303308, an O4 star in Carina; (2) HD 36981, a B5 star in Orion; and (3) TW Hydrae, a T Tauri star of 10 Myr age. Using reduced dissociation probabilities for C18O based on the photolysis experiments yields nebular water slopes approximately 0.95–1.0 for HD 303308 and TW Hya, and approximately 0.8–1.5 for HD 36981. For the central protostar case (TW Hya) with a simplified treatment of the 2-D radiative transfer, slopes approximately 0.95–1.0 are obtained, independent of the C18O dissociation probability. Greatly improved measurements of the C17O and C18O cross sections and dissociation probabilities are in progress.
Effect of differential rearing on the behavioral and adrenocortical response of lambs to a novel environment

Abstract Male lambs were raised under three different social conditions: in isolation, with peers, or with their mothers in small flocks. Differential rearing conditions significantly affected the lambs' behavioral response to open-field testing at 14 days of age. The isolate-reared lambs exhibited withdrawal behavior as compared to the other groups. When retested at 42 days of age, the differences in behavioral response between groups attenuated; however, the isolate-reared lambs continued to exhibit withdrawal behavior. Although the groups displayed different behavioral responses to the stress, there was no difference between groups in the adrenocortical response.
Time-Resolved, Laser-Induced Phase Transformation in Aluminum

The technique of picosecond electron diffraction is used to time resolve the laser-induced melting of thin aluminum films. It is observed that under rapid heating conditions, the long range order of the lattice subsists for lattice temperatures well above the equilibrium point, indicative of superheating. This superheating can be verified by directly measuring the lattice temperature. The collapse time of the long range order is measured and found to vary from 20 ps to several nanoseconds according to the degree of superheating. Two interpretations of the delayed melting are offered, based on the conventional nucleation and point defect theories. While the nucleation theory provides an initial nucleus size and concentration for melting to occur, the point defect theory offers a possible explanation for how the nuclei are originally formed.
GUT breaking on the brane

Abstract We present a five-dimensional supersymmetric SU(5) theory in which the gauge symmetry is broken maximally (i.e., at the 5D Planck scale M ∗ ) on the same 4D brane where chiral matter is localized. Masses of the lightest Kaluza–Klein modes for the colored Higgs and X and Y gauge fields are determined by the compactification scale of the fifth dimension, MC∼1015 GeV, rather than by M ∗ . These fields' wave functions are repelled from the GUT-breaking brane, so that proton decay rates are suppressed below experimental limits. Above the compactification scale, the differences between the standard model gauge couplings evolve logarithmically, so that ordinary logarithmic gauge coupling unification is preserved. The maximal breaking of the grand unified group can also lead to other effects, such as O(1) deviations from SU(5) predictions of Yukawa couplings, even in models utilizing the Froggatt–Nielsen mechanism.
Topological Hochschild homology of twisted group algebras

We show that the topological Hochschild homology spectrum of a twisted group algebra THH(A τ [G]) is the Thom spectrum associated with a parametrized orthogonal spectrum E(A, G). We then analyze the structure of the parametrized orthogonal spectrum E(A, G) and show that it is locally trivial.
The Nature of the Variable Galactic Center Source GCIRS 16SW Revisited: A Massive Eclipsing Binary

We present a reanalysis of our H- and K-band photometry and light curves for GCIRS 16SW, a regular periodic source near the Galactic center. These data include those presented by DePoy et al.; we correct a sign error in their reduction, finding GCIRS 16SW to be an eclipsing binary with no color variations. We find the system to be an equal-mass overcontact binary (both stars overfilling their Roche lobes) in a circular orbit with a period P = 19.4513 days and an inclination angle i = 71°. This confirms and strengthens the findings of Martins et al. that GCIRS 16SW is an eclipsing binary composed of two ~50 M☉ stars, further supporting evidence of recent star formation very close to the Galactic center. Finally, the calculated luminosity of each component is close to the Eddington luminosity, implying that the temperature of 24,400 K given by Najarro et al. might be overestimated for these evolved stars.
Sufficient Conditions on the Optimality of Myopic Sensing in Opportunistic Channel Access: A Unifying Framework

This paper considers a widely studied stochastic control problem arising from opportunistic spectrum access (OSA) in a multi-channel system, with the goal of providing a unifying analytical framework whereby a number of prior results may be viewed as special cases. Specifically, we consider a single wireless transceiver/user with access to $N$ channels, each modeled as an iid discrete-time two-state Markov chain. In each time step the user is allowed to sense $k\leq N$ channels, and subsequently use up to $m\leq k$ channels out of those sensed to be available. Channel sensing is assumed to be perfect, and for each channel use in each time step the user gets a unit reward. The user's objective is to maximize its total discounted or average reward over a finite or infinite horizon. This problem has previously been studied in various special cases including $k=1$ and $m=k\leq N$, often cast as a restless bandit problem, with optimality results derived for a myopic policy that seeks to maximize the immediate one-step reward when the two-state Markov chain model is positively correlated. In this paper we study the general problem with $1\leq m\leq k\leq N$, and derive sufficient conditions under which the myopic policy is optimal for the finite and infinite horizon reward criteria, respectively. It is shown that these results reduce to those derived in prior studies under the corresponding special cases, and thus may be viewed as a set of unifying optimality conditions. Numerical examples are also presented to highlight how and why an optimal policy may deviate from the otherwise-optimal myopic sensing given additional exploration opportunities, i.e., when $m<k$.
D-theory: field theory via dimensional reduction of discrete variables

Abstract A new non-perturbative approach to quantum field theory — D-theory — is proposed, in which continuous classical fields are replaced by discrete quantized variables which undergo dimensional reduction. The 2-d classical O ((3) model emerges from the (2 + 1)-d quantum Heisenberg model formulated in terms of quantum spins. Dimensional reduction is demonstrated explicity by simulating correlation lengths up to 350,000 lattice spacings using a loop cluster algorithm. In the framework of D-theory, gauge theories are formulated in terms of quantum links — the gauge analogs of quantum spins. Quantum links are parallel transporter matrices whose elements are non-commuting operators. They can be expressed as bilinears of anticommuting fermion constituents. In quantum link models dimensional reduction to four dimensions occurs, due to the presence of a 5-d Coulomb phase, whose existence is confirmed by detailed simulations using standard lattice gauge theory. Using Shamir's variant of Kaplan's fermion proposal, in quantum link QCD quarks appear as edge states of a 5-d slab. This naturally protects their chiral symmetries without fine-tuning. The first efficient cluster algorithm for a gauge theory with a continuous gauge group is formulated for the U (1) quantum link model. Improved estimators for Wilson loops are constructed, and dimensional reduction to ordinary lattice QED is verified numerically.