16,512 research outputs found

    Analysis of pressurized and axially loaded orthotropic multicell tanks

    Get PDF
    Nondimensional stress resultants and displacements for multicell tanks of orthotropic construction loaded by internal pressure and axial compressio

    Spatial and Temporal Relationships Between Forest Bird Declines and Prevalence of the Hemlock Woolly Adelgid in the Northeastern United States

    Full text link
    The eastern hemlock (Tsuga canadensis) is a vital foundation tree species throughout the eastern United States, providing essential structural diversity and habitat for more than 120 different animal species. Within the past few decades, T. canadensis has undergone significant declines that are largely associated with the hemlock woolly adelgid (HWA; Adelges tsugae), an exotic, aphid-like insect native to East Asia. From the 1970s to present day, the HWA has spread throughout southern New England, large portions of the Mid-Atlantic region, and parts of Tennessee and the Carolinas. Research has shown that loss of the eastern hemlock is drastically altering forest community structures, potentially impacting a wide variety of forest fauna, including avian populations strongly associated with hemlock forests. Here we present research investigating the correlation between HWA prevalence and recent declines of hemlock-associated forest birds in the Eastern US. We analyzed bird population trends data from the North American Breeding Bird Survey (BBS), US Forest Service HWA data, and land cover data to analyze the population trends of hemlock-associated and forest generalist species in association with the arrival of HWA, taking hemlock density into account. We found a significant correlation between the timing of HWA arrival and declines of conifer forest specialist birds. The Black-throated Green Warbler and the Blue-headed Vireo exhibited significant decline along survey routes after HWA arrival. Populations of some forest generalists (Tufted Titmouse, White-Breasted Nuthatch) were unaffected and continued to increase linearly, while others (Red-Eyed Vireo, Ovenbird) showed minor decrease in population

    Effect of psychotropic drugs on gastric ulcers induced by immobilization: Increased protective effect of amitriptyline caused by chlordiazepoxide

    Get PDF
    Amitriptyline, but not chlordiazepoxide, protects rats from the occurrence of gastric erosions and ulcers following immobilization. When, however, chlordiazepoxide is given together with amitriptyline the protective effect of the latter is markedly increased

    Online Local Learning via Semidefinite Programming

    Full text link
    In many online learning problems we are interested in predicting local information about some universe of items. For example, we may want to know whether two items are in the same cluster rather than computing an assignment of items to clusters; we may want to know which of two teams will win a game rather than computing a ranking of teams. Although finding the optimal clustering or ranking is typically intractable, it may be possible to predict the relationships between items as well as if you could solve the global optimization problem exactly. Formally, we consider an online learning problem in which a learner repeatedly guesses a pair of labels (l(x), l(y)) and receives an adversarial payoff depending on those labels. The learner's goal is to receive a payoff nearly as good as the best fixed labeling of the items. We show that a simple algorithm based on semidefinite programming can obtain asymptotically optimal regret in the case where the number of possible labels is O(1), resolving an open problem posed by Hazan, Kale, and Shalev-Schwartz. Our main technical contribution is a novel use and analysis of the log determinant regularizer, exploiting the observation that log det(A + I) upper bounds the entropy of any distribution with covariance matrix A.Comment: 10 page

    The role of the Polyakov loop in finite density QCD

    Get PDF
    We study the behavior of the fermion determinant at finite temperature and chemical potential, as a function of the Polyakov loop. The phase of the determinant is correlated with the imaginary part of the Polyakov loop. This correlation and its consequences are considered in static QCD, in a toy model of free quarks in a constant A0A_0 background, and in simulations constraining the imaginary part of the Polyakov loop to zero.Comment: 11 pages, 8 Postscript figures, Minor changes, quality of figures improve

    Ion observations from geosynchronous orbit as a proxy for ion cyclotron wave growth during storm times

    Get PDF
    [1] There is still much to be understood about the processes contributing to relativistic electron enhancements and losses in the radiation belts. Wave particle interactions with both whistler and electromagnetic ion cyclotron (EMIC) waves may precipitate or accelerate these electrons. This study examines the relation between EMIC waves and resulting relativistic electron flux levels after geomagnetic storms. A proxy for enhanced EMIC waves is developed using Los Alamos National Laboratory Magnetospheric Plasma Analyzer plasma data from geosynchronous orbit in conjunction with linear theory. In a statistical study using superposed epoch analysis, it is found that for storms resulting in net relativistic electron losses, there is a greater occurrence of enhanced EMIC waves. This is consistent with the hypothesis that EMIC waves are a primary mechanism for the scattering of relativistic electrons and thus cause losses of such particles from the magnetosphere

    Coffin Soul Portals of the Female Xunren in Tomb of Marquis Yi of Zeng

    Get PDF
    There is a significant void in scholarship concerning the Tomb of Marquis Yi of Zeng’s (Zeng Hou Yi), Leigudun M1, Suizhou, Hubei Province, dated to 433 BCE during the Eastern Zhou Dynasty (770-256 BCE) of Bronze Age China, specifically on the lacquer coffins of the female xunren. There is extensive research dedicated to its well-preserved ritual bronze vessels, lacquer wares, and musical instruments, but this tomb is not known for the lacquer designs of portals present on twelve of the twenty-one female companion’s coffins. In this paper, I argue the xunren coffin designs in tomb Leigudun M1 of Zeng Hou Yi are fundamental to uncovering the tomb’s social hierarchy and its function in the afterlife through the presence of portal designs. To begin, I consider archaeological data on the lacquer coffins of the xunren, such as placement and grave goods, and correlate this to lacquer design complexity and portal design on the women’s coffins. I identified parallels between Leigudun M1 and comparable tombs containing burials for the xunren in large quantities that indicate an organized afterlife based on social status. Lastly, I address cosmology and contemporary literature on the afterlife because it illustrates the tradition of hierarchy, movement, and value of souls in the afterlife. By carefully examining the lacquer coffin designs, this study sheds new light on the meaning and value of these coffin soul portals and their relationship to the women and Marquis Yi in the afterlife

    Brane Supersymmetry Breaking

    Get PDF
    We show how to construct chiral tachyon-free perturbative orientifold models, where supersymmetry is broken at the string scale on a collection of branes while, to lowest order, the bulk and the other branes are supersymmetric. In higher orders, supersymmetry breaking is mediated to the remaining sectors, but is suppressed by the size of the transverse space or by the distance from the brane where supersymmetry breaking primarily occurred. This setting is of interest for orbifold models with discrete torsion, and is of direct relevance for low-scale string models. It can guarantee the stability of the gauge hierarchy against gravitational radiative corrections, allowing an almost exact supergravity a millimeter away from a non-supersymmetric world.Comment: 15 pages, LaTe

    To Peter Cicchino, From the Heart

    Get PDF
    • …
    corecore