7,289 research outputs found

    Non-Universal Gaugino Masses, CDMS, and the LHC

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    We consider the possibility that the recently reported events at the CDMS-II direct dark matter detection experiment are the result of coherent scattering of supersymmetric neutralinos. In such a scenario we argue that non-universal soft supersymmetry breaking gaugino masses are favored with a resulting lightest neutralino with significant Higgsino and wino components. We discuss the accompanying signals which must be seen at liquid-xenon direct detection experiments and indirect detection experiments if such a supersymmetric interpretation is to be maintained. We illustrate the possible consequences for early discovery channels at the LHC via a set of benchmark points designed to give rise to an observed event rate comparable to the reported CDMS-II data.Comment: Typos corrected and references adde

    The stoichiometry of P2X2/6 receptor heteromers depends on relative subunit expression levels

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    Fast synaptic transmission involves the operation of ionotropic receptors, which are often composed of at least two types of subunit. We have developed a method, based on atomic force microscopy imaging to determine the stoichiometry and subunit arrangement within ionotropic receptors. We showed recently that the P2X(2) receptor for ATP is expressed as a trimer but that the P2X(6) subunit is unable to oligomerize. In this study we addressed the subunit stoichiometry of heteromers containing both P2X(2) and P2X(6) subunits. We transfected tsA 201 cells with both P2X(2) and P2X(6) subunits, bearing different epitope tags. We manipulated the transfection conditions so that either P2X(2) or P2X(6) was the predominant subunit expressed. By atomic force microscopy imaging of isolated receptors decorated with antiepitope antibodies, we demonstrate that when expression of the P2X(2) subunit predominates, the receptors contain primarily 2 x P2X(2) subunits and 1 x P2X(6) subunit. In contrast, when the P2X(6) subunit predominates, the subunit stoichiometry of the receptors is reversed. Our results show that the composition of P2X receptor heteromers is plastic and dependent on the relative subunit expression levels. We suggest that this property of receptor assembly might introduce an additional layer of subtlety into P2X receptor signaling

    Free Energies of Isolated 5- and 7-fold Disclinations in Hexatic Membranes

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    We examine the shapes and energies of 5- and 7-fold disclinations in low-temperature hexatic membranes. These defects buckle at different values of the ratio of the bending rigidity, κ\kappa, to the hexatic stiffness constant, KAK_A, suggesting {\em two} distinct Kosterlitz-Thouless defect proliferation temperatures. Seven-fold disclinations are studied in detail numerically for arbitrary κ/KA\kappa/K_A. We argue that thermal fluctuations always drive κ/KA\kappa/K_A into an ``unbuckled'' regime at long wavelengths, so that disclinations should, in fact, proliferate at the {\em same} critical temperature. We show analytically that both types of defects have power law shapes with continuously variable exponents in the ``unbuckled'' regime. Thermal fluctuations then lock in specific power laws at long wavelengths, which we calculate for 5- and 7-fold defects at low temperatures.Comment: LaTeX format. 17 pages. To appear in Phys. Rev.

    Twenty-year home-range dynamics of a white-tailed deer matriline

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    We examined the seasonal migration and home-range dynamics of a multigeneration white-tailed deer (Odocoileus virginianus) matriline comprising six females from four generations spanning a 20-year period in northeastern Minnesota. All, from the matriarch to her great-granddaughter, migrated to the same summer and winter ranges, the longest individual record being 14.5 years. Three maternal females concurrently occupied exclusive fawning sites within their ancestral matriarch’s summer range, while two nonmaternal females explored new areas and ranged near their mothers. One great-granddaughter expanded her summer range 1 km beyond the matriarch’s summer range while essentially vacating half of her ancestors’ range and becoming nonmigratory the last 4 years of her life. These data indicate that individual movements of matriline members can potentially expand their ranges beyond the areas occupied by their ancestors through a slow process of small incremental changes. This suggests that the rapid extension of deer range in eastern North America resulted from natal dispersal by yearling deer rather than from the type of home-range expansion reported here. Nous avons étudié la migration saisonnière et la dynamique des déplacements dans les domaines au sein d’une lignée maternelle de plusieurs générations de Cerfs de Virginie (Odocoileus virginianus), lignée composée de six femelles de quatre générations recouvrant une période de 20 ans dans le nord-est du Minnesota. De l’aïeule à son arrière-petite-fille, toutes les femelles occupaient les mêmes domaines d’été et d’hiver, le record d’occupation atteignant 14,5 ans. Trois femelles mères occupaient en même temps des sites de mise-bas exclusifs à l’intérieur du domaine ancestral d’été, alors que deux femelles non mères ont exploré de nouvelles régions et occupaient des domaines voisins de ceux de leurs mères. Une arrière-petite-fille a étendu son domaine d’été de 1 km au-delà de celui de son aïeule, évacuant la moitié du domaine ancestral, et a cessé de migrer au cours des 4 dernières années de sa vie. Ces données indiquent que les déplacements des femelles d’une lignée maternelle peuvent éventuellement agrandir les domaines audelà des limites du domaine de leurs ancêtres, mais très lentement et par petites augmentations seulement. Il semble donc que l’expansion rapide de la répartition du Cerf de Virginie observée en Amérique du Nord résulte de la dispersion des jeunes de l’année à la naissance plutôt que du type d’expansion de domaine tel que décrit ici

    Maternal pomegranate juice intake and brain structure and function in infants with intrauterine growth restriction: A randomized controlled pilot study.

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    Polyphenol-rich pomegranate juice has been shown to have benefit as a neuroprotectant in animal models of neonatal hypoxic-ischemia. No published studies have investigated maternal polyphenol administration as a potential neuroprotectant in at-risk newborns, such as those with intrauterine growth restriction (IUGR). This was a randomized, placebo-controlled, double-blind pilot study to investigate the impact of maternal pomegranate juice intake in pregnancies with IUGR, on newborn brain structure and function at term-equivalent age (TEA). Mothers with IUGR at 24-34 weeks\u27 gestation were recruited from Barnes-Jewish Hospital obstetrical clinic. Consented mothers were randomized to treatment (8 oz. pomegranate juice) or placebo (8 oz. polyphenol-free juice) and continued to take juice daily from enrollment until delivery (mean 20.1 and 27.1 days, respectively). Infants underwent brain MRI at TEA (36-41 weeks\u27 gestation). Brain measures were compared between groups including: brain injury score, brain metrics, brain volumes, diffusion tensor imaging and resting state functional connectivity. Statistical analyses were undertaken as modified intention-to-treat (including randomized participants who received their allocated intervention and whose infants received brain MRI) and per-protocol (including participants who strictly adhered to the protocol, based on metabolite status). Seventy-seven mothers were randomized to treatment (n = 40) or placebo (n = 37). Of these, 28 and 27 infants, respectively, underwent term-equivalent MRI. There were no group differences in brain injury, metrics or volumes. However, treatment subjects displayed reduced diffusivity within the anterior and posterior limbs of the internal capsule compared with placebo. Resting state functional connectivity demonstrated increased correlation and covariance within several networks in treatment subjects, with alterations most apparent in the visual network in per-protocol analyses. Direct effects on health were not found. In conclusion, maternal pomegranate juice intake in pregnancies with known IUGR was associated with altered white matter organization and functional connectivity in the infant brain, suggesting differences in brain structure and function following in utero pomegranate juice exposure, warranting continued investigation. Clinical trial registration. NCT00788866, registered November 11, 2008, initial participant enrollment August 21, 2012

    A Mock Data and Science Challenge for Detecting an Astrophysical Stochastic Gravitational-Wave Background with Advanced LIGO and Advanced Virgo

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    The purpose of this mock data and science challenge is to prepare the data analysis and science interpretation for the second generation of gravitational-wave experiments Advanced LIGO-Virgo in the search for a stochastic gravitational-wave background signal of astrophysical origin. Here we present a series of signal and data challenges, with increasing complexity, whose aim is to test the ability of current data analysis pipelines at detecting an astrophysically produced gravitational-wave background, test parameter estimation methods and interpret the results. We introduce the production of these mock data sets that includes a realistic observing scenario data set where we account for different sensitivities of the advanced detectors as they are continuously upgraded toward their design sensitivity. After analysing these with the standard isotropic cross-correlation pipeline we find that we are able to recover the injected gravitational-wave background energy density to within 2σ2\sigma for all of the data sets and present the results from the parameter estimation. The results from this mock data and science challenge show that advanced LIGO and Virgo will be ready and able to make a detection of an astrophysical gravitational-wave background within a few years of operations of the advanced detectors, given a high enough rate of compact binary coalescing events
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