241 research outputs found

    Gravitational Radiation from Preheating with Many Fields

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    Parametric resonances provide a mechanism by which particles can be created just after inflation. Thus far, attention has focused on a single or many inflaton fields coupled to a single scalar field. However, generically we expect the inflaton to couple to many other relativistic degrees of freedom present in the early universe. Using simulations in an expanding Friedmann-Lema\^itre-Robertson-Walker spacetime, in this paper we show how preheating is affected by the addition of multiple fields coupled to the inflaton. We focus our attention on gravitational wave production--an important potential observational signature of the preheating stage. We find that preheating and its gravitational wave signature is robust to the coupling of the inflaton to more matter fields.Comment: 7 pages, 8 figures, v2 submission version, thank you for comments

    Cartilage-specific ablation of XBP1 signaling in mouse results in a chondrodysplasia characterized by reduced chondrocyte proliferation and delayed cartilage maturation and mineralization

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    SummaryObjectiveTo investigate the in vivo role of the IRE1/XBP1 unfolded protein response (UPR) signaling pathway in cartilage.DesignXbp1flox/flox.Col2a1-Cre mice (Xbp1CartΔEx2), in which XBP1 activity is ablated specifically from cartilage, were analyzed histomorphometrically by Alizarin red/Alcian blue skeletal preparations and X-rays to examine overall bone growth, histological stains to measure growth plate zone length, chondrocyte organization, and mineralization, and immunofluorescence for collagen II, collagen X, and IHH. Bromodeoxyuridine (BrdU) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) analyses were used to measure chondrocyte proliferation and cell death, respectively. Chondrocyte cultures and microdissected growth plate zones were analyzed for expression profiling of chondrocyte proliferation or endoplasmic reticulum (ER) stress markers by Quantitative PCR (qPCR), and of Xbp1 mRNA splicing by RT-PCR to monitor IRE1 activation.ResultsXbp1CartΔEx2 displayed a chondrodysplasia involving dysregulated chondrocyte proliferation, growth plate hypertrophic zone shortening, and IRE1 hyperactivation in chondrocytes. Deposition of collagens II and X in the Xbp1CartΔEx2 growth plate cartilage indicated that XBP1 is not required for matrix protein deposition or chondrocyte hypertrophy. Analyses of mid-gestation long bones revealed delayed ossification in Xbp1CartΔEx2 embryos. The rate of chondrocyte cell death was not significantly altered, and only minimal alterations in the expression of key markers of chondrocyte proliferation were observed in the Xbp1CartΔEx2 growth plate. IRE1 hyperactivation occurred in Xbp1CartΔEx2 chondrocytes but was not sufficient to induce regulated IRE1-dependent decay (RIDD) or a classical UPR.ConclusionOur work suggests roles for XBP1 in regulating chondrocyte proliferation and the timing of mineralization during endochondral ossification, findings which have implications for both skeletal development and disease

    Влияние моделей обратного тока насыщения диода на выходные характеристики двух-диодной модели солнечной батареи в среде Matlab Simulink

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    В работе проводилось моделирование солнечной батареи в программном обеспечении MATLAB Simulink. Изучались выходные параметры солнечной батареи в зависимости от модели обратного тока насыщения диода. Полученными результатами являются вольт-амперные и вольт-ваттные характеристики, показывающие влияние модели обратного тока насыщения диода на выходные параметры солнечной батареи.The work was carried out modeling of the solar battery in the software MATLAB Simulink. The output parameters of the solar battery were studied depending on the model of the reverse current saturation of the diode. The results are current-voltage and voltage-watt characteristics, showing the influence of the model of the inverse diode saturation current on the output parameters of the solar battery

    Onshore carboniferous basins : third review report

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    focussed on achieving a better understanding of the Bowland Shale in northern England. The broad aim is to understand the geological variability of the formation from a basin- through to microscale, and assess the impact of variability on hydrocarbon generation, storage and production (for example, the co-incidence or otherwise of factors including organic content and kerogen type; mineralogy; and engineering behaviour). This report is the third summary report describing activities of the consortium, covering the period October 2015 – June 2016. A series of 3 inter-related work packages are designed to improve understanding of the Bowland Shale of northern England. The original numbering of these is retained to allow continuity between previous progress reports. Specifically, these work packages address: 1. Work Package 1,2: Basin analysis of the Pennine Basin; Characterization of shale facies; 2. Work Package 3: Development of chemical stratigraphies through prospective parts of the stratigraphic column; 3. Work Package 4: Hydromechanical behaviour of shales. Two work packages outside the consortium are also considered, namely 4. Retrieval of new materials to test 5. Reprocessing of 3D seismic data to assess rock properties Descriptions of previous activities have been released, covering the period July 2014 to March 2015 (Hough et al., 2015a), and the period April 2015 to September 2015 (Hough et al., 2015b). The consortium currently has 4 sponsors who each contribute £25 000 per year; BGS contributes around £200 000 annually, which results in an annual budget of approximately £300 000. The consortium is planned to last 3 years initially, and started in July 2014 with a scheduled end date of June 2017

    Inferring Deleterious-Mutation Parameters in Natural Daphnia Populations

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    Deng and Lynch (1, 2) proposed to characterize deleterious genomic mutations from changes in the mean and genetic variance of fitness traits upon selfing in outcrossing populations. Such observations can be readily acquired in cyclical parthenogens. Selfing and life-table experiments were performed for two such Daphnia populations. A significant inbreeding depression and an increase of genetic variance for all traits analyzed were observed. Deng and Lynch's (2) procedures were employed to estimate the genomic mutation rate (U), mean dominance coefficient ( [Image: see text] ), mean selection coefficient ( [Image: see text] ), and scaled genomic mutational variance ( [Image: see text] ). On average, [Image: see text] , [Image: see text] , [Image: see text] and [Image: see text] (^ indicates an estimate) are 0.84, 0.30, 0.14 and 4.6E-4 respectively. For the true values, the [Image: see text] and [Image: see text] are lower bounds, and [Image: see text] and [Image: see text] upper bounds

    Identification of TGFβ-related genes regulated in murine osteoarthritis and chondrocyte hypertrophy by comparison of multiple microarray datasets

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    Objective: Osteoarthritis (OA) is a joint disease characterized by progressive degeneration of articular cartilage. Some features of OA, including chondrocyte hypertrophy and focal calcification of articular cartilage, resemble the endochondral ossification processes. Alterations in transforming growth factor β (TGFβ) signaling have been associated with OA as well as with chondrocyte hypertrophy. Our aim was to identify novel candidate genes implicated in chondrocyte hypertrophy during OA pathogenesis by determining which TGFβ-related genes are regulated during murine OA and endochondral ossification. Methods: A list of 580 TGFβ-related genes, including TGFβ signaling pathway components and TGFβ-target genes, was generated. Regulation of these TGFβ-related genes was a

    Calculation of the Flux of Atmospheric Neutrinos

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    Atmospheric neutrino-fluxes are calculated over the wide energy range from 30 MeV to 3,000 GeV for the study of neutrino-physics using the data from underground neutrino-detectors. The atmospheric muon-flux at high altitude and at sea level is studied to calibrate the neutrino-fluxes at low energies and high energies respectively. The agreement of our calculation with observations is satisfactory. The uncertainty of atmospheric neutrino-fluxes is also studied.Comment: 51 page

    Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

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    The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

    Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

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    A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

    Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC

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