751 research outputs found

    Two-point theory for the differential self-interrogation Feynman-alpha method

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    A Feynman-alpha formula has been derived in a two region domain pertaining the stochastic differential self-interrogation (DDSI) method and the differential die-away method (DDAA). Monte Carlo simulations have been used to assess the applicability of the variance to mean through determination of the physical reaction intensities of the physical processes in the two domains. More specifically, the branching processes of the neutrons in the two regions are described by the Chapman - Kolmogorov equation, including all reaction intensities for the various processes, that is used to derive a variance to mean relation for the process. The applicability of the Feynman-alpha or variance to mean formulae are assessed in DDSI and DDAA of spent fuel configurations.Comment: 15 pages, 5 figures. Submitted to EPJ Plu

    Dynamic expressivity with static optimization for streaming languages

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    Developers increasingly use streaming languages to write applications that process large volumes of data with high throughput. Unfortunately, when picking which streaming language to use, they face a difficult choice. On the one hand, dynamically scheduled languages allow developers to write a wider range of applications, but cannot take advantage of many crucial optimizations. On the other hand, statically scheduled languages are extremely performant, but have difficulty expressing many important streaming applications. This paper presents the design of a hybrid scheduler for stream processing languages. The compiler partitions the streaming application into coarse-grained subgraphs separated by dynamic rate boundaries. It then applies static optimizations to those subgraphs. We have implemented this scheduler as an extension to the StreamIt compiler. To evaluate its performance, we compare it to three scheduling techniques used by dynamic systems (OS thread, demand, and no-op) on a combination of micro-benchmarks and real-world inspired synthetic benchmarks. Our scheduler not only allows the previously static version of StreamIt to run dynamic rate applications, but it outperforms the three dynamic alternatives. This demonstrates that our scheduler strikes the right balance between expressivity and performance for stream processing languages.National Science Foundation (U.S.) (CCF-1162444

    A genealĂłgiai kutatĂĄs lehetƑsĂ©gei a bĂ©csi Kriegsarchivban

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    A könyvfejezetben a Habsburg Birodalomban mindvĂ©gig jelentƑs szerepet jĂĄtszĂł hadsereg szemĂ©lyĂŒgyi anyagainak legfontosabb tĂ­pusai, a mustrajegyzĂ©kek, ĂĄllomĂĄnytĂĄblĂĄzatok, a revĂ­ziĂłs listĂĄk, az ĂșjoncozĂĄsi- Ă©s ĂĄthelyezĂ©si listĂĄk, a törzskönyvi lapok, a minƑsĂ­tĂ©si jegyzĂ©kek, a katonai anyakönyvek Ă©s a nyugdĂ­jazĂĄsi jegyzƑkönyvek, illetve ezen forrĂĄstĂ­pusok fejlƑdĂ©se, szerkezeti felĂ©pĂ­tĂ©se Ă©s fƑbb tartalmi jegyei kerĂŒlnek bemutatĂĄsra. Ezek a többnyire adatgazdag irategyĂŒttesek ugyanis szĂ©leskörƱ lehetƑsĂ©get biztosĂ­tanak a mindenkori haderƑben szolgĂĄlatot teljesĂ­tƑ szemĂ©lyekkel kapcsolatos genealĂłgiai Ă©s Ă©letrajzi jellegƱ kutatĂĄsok szĂĄmĂĄra is, amit jelentƑs mĂ©rtĂ©kben megkönnyĂ­t, hogy a vonatkozĂł forrĂĄsok többsĂ©ge egy helyen, a bĂ©csi HadilevĂ©ltĂĄrban talĂĄlhatĂł. IsmertetĂ©sre kerĂŒlnek tovĂĄbbĂĄ a nem kimondottan szemĂ©lyĂŒgyi katonai forrĂĄsoknak tekinthetƑ, de genealĂłgiai szempontbĂłl relevĂĄns iratanyagok (Udvari HaditanĂĄcs iratai, RĂ©gi TĂĄbori AktĂĄk) is. Az emlĂ­tett forrĂĄsegyĂŒttesek keletkezĂ©sĂ©nek Ă©s mindenkori ƑrzĂ©si helyĂ©nek ĂĄttekintĂ©se rĂ©vĂ©n egyĂșttal a bĂ©csi hadilevĂ©ltĂĄr fejlƑdĂ©störtĂ©nete is vĂĄzlatosan bemutatĂĄsra kerĂŒl. VĂ©gezetĂŒl pedig a szerzƑ a 18–19. szĂĄzad fordulĂłjĂĄnak csĂĄszĂĄri-kirĂĄlyi tisztikarĂĄra irĂĄnyulĂł sajĂĄt kutatĂĄsainak tapasztalatait Ă©s mĂłdszertanĂĄt mutatja be nĂ©hĂĄny Ă©rzĂ©kletes pĂ©ldĂĄn keresztĂŒl

    The Initial Step in Human Immunodeficiency Virus Type 1 GagProPol Processing Can Be Regulated by Reversible Oxidation

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    BACKGROUND: Maturation of human immunodeficiency virus type 1 (HIV-1) occurs upon activation of HIV-1 protease embedded within GagProPol precursors and cleavage of Gag and GagProPol polyproteins. Although reversible oxidation can regulate mature protease activity as well as retrovirus maturation, it is possible that the effects of oxidation on viral maturation are mediated in whole, or part, through effects on the initial intramolecular cleavage event of GagProPol. In order assess the effect of reversible oxidation on this event, we developed a system to isolate the first step in protease activation involving GagProPol. METHODOLOGY/PRINCIPAL FINDINGS: To determine if oxidation influences this step, we created a GagProPol plasmid construct (pGPfs-1C) that encoded mutations at all cleavage sites except p2/NC, the initial cleavage site in GagProPol. pGPfs-1C was used in an in vitro translation assay to observe the behavior of this initial step without interference from subsequent processing events. Diamide, a sulfhydral oxidizing agent, inhibited processing at p2/NC by >60% for pGPfs-1C and was readily reversed with the reductant, dithiothreitol. The ability to regulate processing by reversible oxidation was lost when the cysteines of the embedded protease were mutated to alanine. Unlike mature protease, which requires only oxidation of cys95 for inhibition, both cysteines of the embedded protease contributed to this inhibition. CONCLUSIONS/SIGNIFICANCE: We developed a system that can be used to study the first step in the cascade of HIV-1 GagProPol processing and show that reversible oxidation of cysteines of HIV-1 protease embedded in GagProPol can block this initial GagProPol autoprocessing. This type of regulation may be broadly applied to the majority of retroviruses

    Channelized lava flows at the East Pacific Rise crest 9°–10°N : the importance of off-axis lava transport in developing the architecture of young oceanic crust

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    Author Posting. © American Geophysical Union, 2005. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 6 (2005): Q08005, doi:10.1029/2005GC000912.Submarine lava flows are the building blocks of young oceanic crust. Lava erupted at the ridge axis is transported across the ridge crest in a manner dictated by the rheology of the lava, the characteristics of the eruption, and the topography it encounters. The resulting lava flows can vary dramatically in form and consequently in their impact on the physical characteristics of the seafloor and the architecture of the upper 50–500 m of the oceanic crust. We have mapped and measured numerous submarine channelized lava flows at the East Pacific Rise (EPR) crest 9°–10°N that reflect the high-effusion-rate and high-flow-velocity end-member of lava eruption and transport at mid-ocean ridges. Channel systems composed of identifiable segments 50–1000 m in length extend up to 3 km from the axial summit trough (AST) and have widths of 10–50 m and depths of 2–3 m. Samples collected within the channels are N-MORB with Mg# indicating eruption from the AST. We produce detailed maps of lava surface morphology across the channel surface from mosaics of digital images that show lineated or flat sheets at the channel center bounded by brecciated lava at the channel margins. Modeled velocity profiles across the channel surface allow us to determine flux through the channels from 0.4 to 4.7 × 103 m3/s, and modeled shear rates help explain the surface morphology variation. We suggest that channelized lava flows are a primary mechanism by which lava accumulates in the off-axis region (1–3 km) and produces the layer 2A thickening that is observed at fast and superfast spreading ridges. In addition, the rapid, high-volume-flux eruptions necessary to produce channelized flows may act as an indicator of the local magma budget along the EPR. We find that high concentrations of channelized lava flows correlate with local, across-axis ridge morphology indicative of an elevated magma budget. Additionally, in locations where channelized flows are located dominantly to the east or west of the AST, the ridge crest is asymmetric, and layer 2A appears to thicken over a greater distance from the AST toward the side of the ridge crest where the channels are located.This work was supported by NSF grant OCE-9819261 (to H.S., M.A.T., and D.J.F.) as well as the Postdoctoral Scholar Program at the Woods Hole Oceanographic Institution, with funding provided by the Penzance Endowed Discretionary Fund

    Tumor cell heterogeneity and resistance; report from the 2018 Coffey‐Holden Prostate Cancer Academy Meeting

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147081/1/pros23729.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147081/2/pros23729_am.pd

    Ionizing Radiation-Induced Oxidative Stress Alters miRNA Expression

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    ). treatment, and 45 after etoposide treatment. Substantial overlap between the miRNA expression changes between agents was observed suggesting a signature miRNA response to cell stress. Changes in the expression of selected miRNA species varied in response to radiation dose and time. Finally, production of reactive oxygen species (ROS) increased with increasing doses of radiation and pre-treatment with the thiol antioxidant cysteine decreased both ROS production and the miRNA response to radiation., and etoposide. Additionally, pre-treatment with cysteine prevented radiation-induced alterations in miRNA expression which suggests that miRNAs are responsive to oxidative stress. Taken together, these results imply that miRNAs play a role in cellular defense against exogenous stress and are involved in the generalized cellular response to genotoxic oxidative stress
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