16,192 research outputs found

    Interim solar cell testing procedures for terrestrial applications

    Get PDF
    An interim draft of a set of test procedures, developed by NASA/ERDA, for the manufacture of solar cells is introduced. This version includes procedures for cell testing both outdoors in natural sunlight and indoors in simulated sunlight, a description of the necessary apparatus and equipment, the calibration and use of standard solar cells, and a proposed air-mass-two (AM2) solar spectrum

    Decay widths of large-spin mesons from the non-critical string/gauge duality

    Full text link
    In this paper, we use the non-critical string/gauge duality to calculate the decay widths of large-spin mesons. Since it is believed that the string theory of QCD is not a ten dimensional theory, we expect that the non-critical versions of ten dimensional black hole backgrounds lead to better results than the critical ones. For this purpose we concentrate on the confining theories and consider two different six dimensional black hole backgrounds. We choose the near extremal AdS6 model and the near extremal KM model to compute the decay widths of large-spin mesons. Then, we present our results from these two non-critical backgrounds and compare them together with those from the critical models and experimental data.Comment: 21 pages and 3 figure

    Cranial sutures work collectively to distribute strain throughout the reptile skull

    Get PDF
    The skull is composed of many bones that come together at sutures. These sutures are important sites of growth, and as growth ceases some become fused while others remain patent. Their mechanical behaviour and how they interact with changing form and loadings to ensure balanced craniofacial development is still poorly understood. Early suture fusion often leads to disfiguring syndromes, thus is it imperative that we understand the function of sutures more clearly. By applying advanced engineering modelling techniques, we reveal for the first time that patent sutures generate a more widely distributed, high level of strain throughout the reptile skull. Without patent sutures, large regions of the skull are only subjected to infrequent low-level strains that could weaken the bone and result in abnormal development. Sutures are therefore not only sites of bone growth, but could also be essential for the modulation of strains necessary for normal growth and development in reptiles

    Evidence for fast thermalization in the plane-wave matrix model

    Full text link
    We perform a numerical simulation of the classical evolution of the plane-wave matrix model with semiclassical initial conditions. Some of these initial conditions thermalize and are dual to a black hole forming from the collision of D-branes in the plane wave geometry. In particular, we consider a large fuzzy sphere (a D2-brane) plus a single eigenvalue (a D0-particle) going exactly through the center of the fuzzy sphere and aimed to intersect it. Including quantum fluctuations of the off-diagonal modes in the initial conditions, with sufficient kinetic energy the configuration collapses to a small size. We also find evidence for fast thermalization: rapidly decaying autocorrelation functions at late times with respect to the natural time scale of the system.Comment: 5 pages, 5 figures, revtex4 format; v2: minor typos fixed; v3: 8 pages, 9 figures, minor changes, includes a supplement as appeared on PR

    Sensitization of renal carcinoma cells to TRAIL-induced apoptosis by rocaglamide and analogs

    Get PDF
    Rocaglamide has been reported to sensitize several cell types to TRAIL-induced apoptosis. In recent years, advances in synthetic techniques have led to generation of novel rocaglamide analogs. However, these have not been extensively analyzed as TRAIL sensitizers, particularly in TRAIL-resistant renal cell carcinoma cells. Evaluation of rocaglamide and analogs identified 29 compounds that are able to sensitize TRAIL-resistant ACHN cells to TRAIL-induced, caspase-dependent apoptosis with sub-µM potency which correlated with their potency as protein synthesis inhibitors and with loss of cFLIP protein in the same cells. Rocaglamide alone induced cell cycle arrest, but not apoptosis. Rocaglates averaged 4–5-fold higher potency as TRAIL sensitizers than as protein synthesis inhibitors suggesting a potential window for maximizing TRAIL sensitization while minimizing effects of general protein synthesis inhibition. A wide range of other rocaglate effects (e.g. on JNK or RAF-MEK-ERK signaling, death receptor levels, ROS, ER stress, eIF4E phosphorylation) were assessed, but did not contribute to TRAIL sensitization. Other than a rapid loss of MCL-1, rocaglates had minimal effects on mitochondrial apoptotic pathway proteins. The identification of structurally diverse/mechanistically similar TRAIL sensitizing rocaglates provides insights into both rocaglate structure and function and potential further development for use in RCC-directed combination therapy.This project has been funded in whole or in part with Federal funds from the National Cancer Institute, National Institutes of Health, under Contract No. HHSN261200800001E. The content of this publication does not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government. This research was supported [in part] by the Intramural Research Program of NIH, Frederick. National Lab, Center for Cancer Research. Research performed at Boston University was supported in part by NIH R35 GM118173. Work at the BU-CMD is supported by R24 GM111625. (HHSN261200800001E - National Cancer Institute, National Institutes of Health; Intramural Research Program of NIH, Frederick. National Lab, Center for Cancer Research; R35 GM118173 - NIH; R24 GM111625)Published versio

    Memory and Musical Expectation for Tones in Cultural Context

    Get PDF
    WE EXPLORED HOW MUSICAL CULTURE SHAPES ONE\u27S listening experience.Western participants heard a series of tones drawn from either the Western major mode (culturally familiar) or the Indian thaat Bhairav (culturally unfamiliar) and then heard a test tone. They made a speeded judgment about whether the test tone was present in the prior series of tones. Interactions between mode (Western or Indian) and test tone type (congruous or incongruous) reflect the utilization of Western modal knowledge to make judgments about the test tones. False alarm rates were higher for test tones congruent with the major mode than for test tones congruent with Bhairav. In contrast, false alarm rates were lower for test tones incongruent with the major mode than for test tones incongruent with Bhairav. These findings suggest that one\u27s internalized cultural knowledge may drive musical expectancies when listening to music of an unfamiliar modal system

    Gauge covariance and the fermion-photon vertex in three- and four- dimensional, massless quantum electrodynamics

    Full text link
    In the quenched approximation, the gauge covariance properties of three vertex Ans\"{a}tze in the Schwinger-Dyson equation for the fermion self energy are analysed in three- and four- dimensional quantum electrodynamics. Based on the Cornwall-Jackiw-Tomboulis effective action, it is inferred that the spectral representation used for the vertex in the gauge technique cannot support dynamical chiral symmetry breaking. A criterion for establishing whether a given Ansatz can confer gauge covariance upon the Schwinger-Dyson equation is presented and the Curtis and Pennington Ansatz is shown to satisfy this constraint. We obtain an analytic solution of the Schwinger-Dyson equation for quenched, massless three-dimensional quantum electrodynamics for arbitrary values of the gauge parameter in the absence of dynamical chiral symmetry breaking.Comment: 17 pages, PHY-7143-TH-93, REVTE
    • …
    corecore