65 research outputs found

    The New Look pMSSM with Neutralino and Gravitino LSPs

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    The pMSSM provides a broad perspective on SUSY phenomenology. In this paper we generate two new, very large, sets of pMSSM models with sparticle masses extending up to 4 TeV, where the lightest supersymmetric particle (LSP) is either a neutralino or gravitino. The existence of a gravitino LSP necessitates a detailed study of its cosmological effects and we find that Big Bang Nucleosynthesis places strong constraints on this scenario. Both sets are subjected to a global set of theoretical, observational and experimental constraints resulting in a sample of \sim 225k viable models for each LSP type. The characteristics of these two model sets are briefly compared. We confront the neutralino LSP model set with searches for SUSY at the 7 TeV LHC using both the missing (MET) and non-missing ET ATLAS analyses. In the MET case, we employ Monte Carlo estimates of the ratios of the SM backgrounds at 7 and 8 TeV to rescale the 7 TeV data-driven ATLAS backgrounds to 8 TeV. This allows us to determine the pMSSM parameter space coverage for this collision energy. We find that an integrated luminosity of \sim 5-20 fb^{-1} at 8 TeV would yield a substantial increase in this coverage compared to that at 7 TeV and can probe roughly half of the model set. If the pMSSM is not discovered during the 8 TeV run, then our model set will be essentially void of gluinos and lightest first and second generation squarks that are \lesssim 700-800 GeV, which is much less than the analogous mSUGRA bound. Finally, we demonstrate that non-MET SUSY searches continue to play an important role in exploring the pMSSM parameter space. These two pMSSM model sets can be used as the basis for investigations for years to come.Comment: 54 pages, 22 figures; typos fixed, references adde

    A review of the Late Permian – Early Triassic conodont record and its significance for the end-Permian mass extinction

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    As a marine microfossil with a long-lasting fossil record stretching from the Cambrian to the Triassic, the tiny conodont plays an important role for the study of the end-Permian mass extinction. In the past few decades, numerous studies on Permian-Triassic conodonts have been published. This paper summarizes the progress made on high-resolution conodont biostratigraphy, timing of the mass extinction across the Permian-Triassic Boundary, conodont apparatus and phylogeny, conodont size variation, conodont oxygen isotope as well as other isotopes and chemical elements. Finally, future perspectives are also discussed

    Performance of Lactating Dairy Cows Fed Dried Sardines

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    To utilize locally available feed resources with livestock production in hot climates, dried sardines were incorporated into diets for lactating dairy cows. Fourteen Holstein and 13 Australian Milk Zebu multiparous cows were used in a 70-day continuous feeding experiment. lsonitrogenous and isoenergetic diets containing either soybean meal or dried sardines (supplied 40% of dietary crude protein) were fed ad - libitum. Comparisons between diets were made during the 7-week experimental period. The experiment was conducted as a 2 x 2 factorial arrangement of treatment, with diet and breed as main factors. Ruminal pH, ammonia N, total and individual volatile fatty acids concentrations were not altered by the feeding of dried sardines. Intakes of dry matter, energy, crude protein, and acid detergent fiber were lower (P0.05) in Holstein cows fed dried sardines than those fed the control diet (16.2 vs 15.1 kg/d). Feeding of dried sardines did not affect milk composition and compositional yields. Milk production was higher (P<0.01) in Holstein than Australian Milk Zebu cows. Effect of diet and breed interaction on milk production was significant (P<0.01 ). Potential of feeding marine proteins may be higher for higher milk producers (Holstein) than lower producers (Australian Milk Zebu). Reproduction parameters, body condition scores, and heat-stress associated parameters were not affected by the feeding of dried sardines. This study suggests that dried sardines could be incorporated into diets of lactating dairy cows without affecting milk production

    Importin 13-dependent axon diameter growth regulates conduction speeds along myelinated CNS axons

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    Axon diameter influences the conduction properties of myelinated axons, both directly, and indirectly through effects on myelin. However, we have limited understanding of mechanisms controlling axon diameter growth in the central nervous system, preventing systematic dissection of how manipulating diameter affects myelination and conduction along individual axons. Here we establish zebrafish to study axon diameter. We find that importin 13b is required for axon diameter growth, but does not affect cell body size or axon length. Using neuron-specific ipo13b mutants, we assess how reduced axon diameter affects myelination and conduction, and find no changes to myelin thickness, precision of action potential propagation, or ability to sustain high frequency firing. However, increases in conduction speed that occur along single myelinated axons with development are tightly linked to their growth in diameter. This suggests that axon diameter growth is a major driver of increases in conduction speeds along myelinated axons over time
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