448 research outputs found

    Evaluation of methods for seismic analysis of mixed-oxide fuel fabrication plants

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    Guidelines are needed for selecting appropriate methods of structural analyses to evaluate the seismic hazard of mixed-oxide fuel fabrication plants. This study examines the different available methods and their applicability to fabrication plants. These results should provide a basis for establishing guidelines recommending methods of analysis to ensure safe design against seismic hazards. Using the Westinghouse Recycle Fuels Plant as representative of future mixed-oxide fuel fabrication plants, critical structures and equipment (systems, components, and piping/ducting) were identified. These included the manufacturing building and 11 different pieces of equipment. After examination of the dynamic response characteristics of the building and the different methods available to analyze equipment, appropriate methods of analyses were recommended. Because critical equipment analysis and test methods generally use floor-response spectra as their seismic input loading, several methods used to generate floor spectra were also examined. These include the time-history approach and the Kapur and Biggs approximate methods. The examination included the effect of site characteristics and both horizontal and vertical structural response. (auth

    Field Estimates of Parentage Reveal Sexually Antagonistic Selection on Body Size in a Population of Anolis Lizards

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    Sexual dimorphism evolves when selection favors different phenotypic optima between the sexes. Such sexually antagonistic selection creates intralocus sexual conflict when traits are genetically correlated between the sexes and have sex‐specific optima. Brown anoles are highly sexually dimorphic: Males are on average 30% longer than females and 150% heavier in our study population. Viability selection on body size is known to be sexually antagonistic, and directional selection favors large male size whereas stabilizing selection constrains females to remain small. We build on previous studies of viability selection by measuring sexually antagonistic selection using reproductive components of fitness over three generations in a natural population of brown anoles. We estimated the number of offspring produced by an individual that survived to sexual maturity (termed RSV), a measure of individual fitness that includes aspects of both individual reproductive success and offspring survival. We found directional selection on male body size, consistent with previous studies of viability selection. However, selection on female body size varied among years, and included periods of positive directional selection, quadratic stabilizing selection, and no selection. Selection acts differently in the sexes based on both survival and reproduction and sexual conflict appears to be a persistent force in this species

    The role of microparticles in pathomechanisms of diabetic retinopathy : analysis of intercellular communication mechanisms in endothelial aging : case control study in patients with metabolic syndrome, diabetes type 1 and type 2

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    The project is proposed to explain the role of specific circulating microparticles (MPs) as conveyors in trafficking bio-active molecules in type 1 (T1DM) and type 2 (T2DM) diabetic patients with risk of diabetic retinopathy (DR) and in patients with metabolic syndrome (MS). The possible role of miRNAs as modulators of these processes (in switching on/off mechanism on the molecular level) is proposed. An increased number of MPs with respect to glucose concentrations and levels of proangiogenic factors in vivo (patients’ plasma) is expected. The relationship between age of patents and MP content (cell membrane glycoproteins, phosphatidylserine or miRNA profile) is possible. MPs will be obtained from T1DM (n = 30) T2DM (n = 30), MS (n = 30) and controls (n = 30). Retinopathy in diabetic patients will be assessed by imaging method. Biological profile of MPs will be assessed in vitro by means of flow cytometry, molecular biology methods and cell proliferation assays

    Second harmonic generation microscopy investigation of the crystalline ultrastructure of three barley starch lines affected by hydration

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    Second harmonic generation (SHG) microscopy is employed to study changes in crystalline organization due to altered gene expression and hydration in barley starch granules. SHG intensity and susceptibility ratio values (R’(SHG)) are obtained using reduced Stokes-Mueller polarimetric microscopy. The maximum R’(SHG) values occur at moderate moisture indicating the narrowest orientation distribution of nonlinear dipoles from the cylindrical axis of glucan helices. The maximum SHG intensity occurs at the highest moisture and amylopectin content. These results support the hypothesis that SHG is caused by ordered hydrogen and hydroxyl bond networks which increase with hydration of starch granules

    A Machine Learning Method to Infer Fundamental Stellar Parameters from Photometric Light Curves

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    A fundamental challenge for wide-field imaging surveys is obtaining follow-up spectroscopic observations: there are > 10910^9 photometrically cataloged sources, yet modern spectroscopic surveys are limited to ~few x 10610^6 targets. As we approach the Large Synoptic Survey Telescope (LSST) era, new algorithmic solutions are required to cope with the data deluge. Here we report the development of a machine-learning framework capable of inferring fundamental stellar parameters (Teff, log g, and [Fe/H]) using photometric-brightness variations and color alone. A training set is constructed from a systematic spectroscopic survey of variables with Hectospec/MMT. In sum, the training set includes ~9000 spectra, for which stellar parameters are measured using the SEGUE Stellar Parameters Pipeline (SSPP). We employed the random forest algorithm to perform a non-parametric regression that predicts Teff, log g, and [Fe/H] from photometric time-domain observations. Our final, optimized model produces a cross-validated root-mean-square error (RMSE) of 165 K, 0.39 dex, and 0.33 dex for Teff, log g, and [Fe/H], respectively. Examining the subset of sources for which the SSPP measurements are most reliable, the RMSE reduces to 125 K, 0.37 dex, and 0.27 dex, respectively, comparable to what is achievable via low-resolution spectroscopy. For variable stars this represents a ~12-20% improvement in RMSE relative to models trained with single-epoch photometric colors. As an application of our method, we estimate stellar parameters for ~54,000 known variables. We argue that this method may convert photometric time-domain surveys into pseudo-spectrographic engines, enabling the construction of extremely detailed maps of the Milky Way, its structure, and history

    Seismic response and failure analyses of a mixed-oxide fuel fabrication plant

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