698 research outputs found

    Three-body collisions in Boltzmann-Uehling-Uhlenbeck theory

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    Aiming at a microscopic description of heavy ion collisions in the beam energy region of about 10 A GeV, we extend the Giessen Boltzmann-Uehling-Uhlenbeck (GiBUU) transport model by including a relativistic mean field, in-medium baryon-baryon cross sections and three-body collisions. The model is then compared with experimental data for central Au+Au collisions at 2-10 A GeV and central Pb+Pb collisions at 30 and 40 A GeV on the proton rapidity spectra, the midrapidity yields of π+\pi^+, K±K^\pm and (Λ+Σ0)(\Lambda+\Sigma^0), and the transverse mass spectra of π±\pi^\pm and K±K^\pm. The three-body collisions increase the inverse slope parameters of the hadron mm_\perp-spectra to a good agreement with the data.Comment: 26 pages, 9 figures, figures added, discussion extended, results not changed, version accepted in Phys. Rev.

    DCC gene network in the prefrontal cortex is associated with total brain volume in childhood

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    BACKGROUND: Genetic variation in the guidance cue DCC gene is linked to psychopathologies involving dysfunction in the prefrontal cortex. We created an expression-based polygenic risk score (ePRS) based on the DCC coexpression gene network in the prefrontal cortex, hypothesizing that it would be associated with individual differences in total brain volume. METHODS: We filtered single nucleotide polymorphisms (SNPs) from genes coexpressed with DCC in the prefrontal cortex obtained from an adult postmortem donors database (BrainEAC) for genes enriched in children 1.5 to 11 years old (BrainSpan). The SNPs were weighted by their effect size in predicting gene expression in the prefrontal cortex, multiplied by their allele number based on an individual's genotype data, and then summarized into an ePRS. We evaluated associations between the DCC ePRS and total brain volume in children in 2 community-based cohorts: the Maternal Adversity, Vulnerability and Neurodevelopment (MAVAN) and University of California, Irvine (UCI) projects. For comparison, we calculated a conventional PRS based on a genome-wide association study of total brain volume. RESULTS: Higher ePRS was associated with higher total brain volume in children 8 to 10 years old (β = 0.212, p = 0.043; n = 88). The conventional PRS at several different thresholds did not predict total brain volume in this cohort. A replication analysis in an independent cohort of newborns from the UCI study showed an association between the ePRS and newborn total brain volume (β = 0.101, p = 0.048; n = 80). The genes included in the ePRS demonstrated high levels of coexpression throughout the lifespan and are primarily involved in regulating cellular function. LIMITATIONS: The relatively small sample size and age differences between the main and replication cohorts were limitations. CONCLUSION: Our findings suggest that the DCC coexpression network in the prefrontal cortex is critically involved in whole brain development during the first decade of life. Genes comprising the ePRS are involved in gene translation control and cell adhesion, and their expression in the prefrontal cortex at different stages of life provides a snapshot of their dynamic recruitment

    On Tackling the Limits of Resolution in SAT Solving

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    The practical success of Boolean Satisfiability (SAT) solvers stems from the CDCL (Conflict-Driven Clause Learning) approach to SAT solving. However, from a propositional proof complexity perspective, CDCL is no more powerful than the resolution proof system, for which many hard examples exist. This paper proposes a new problem transformation, which enables reducing the decision problem for formulas in conjunctive normal form (CNF) to the problem of solving maximum satisfiability over Horn formulas. Given the new transformation, the paper proves a polynomial bound on the number of MaxSAT resolution steps for pigeonhole formulas. This result is in clear contrast with earlier results on the length of proofs of MaxSAT resolution for pigeonhole formulas. The paper also establishes the same polynomial bound in the case of modern core-guided MaxSAT solvers. Experimental results, obtained on CNF formulas known to be hard for CDCL SAT solvers, show that these can be efficiently solved with modern MaxSAT solvers

    Digital image correlation vibrometry with low speed equipment

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    A low-cost method is presented which enables digital image correlation (DIC) with conventional cameras (i.e. not high-speed) to be used for determination of vibration deflected shapes via the use of a stroboscopic lamp and some simple ancillary circuits. For each natural frequency of the structure under consideration, a sequence of images is captured asynchronously with the vibrations using the DIC system and the resulting displacement fields are correlated with the excitation signal driving the vibration using a least-squares approach. Three approaches for performing this correlation are outlined, one of which is developed into the algorithm used for processing the present results to obtain the amplitude and phase of the vibration at each point on the specimen, allowing the deflected shape to be reconstructed. This process is illustrated using the example of a vibrating aluminium plate. The resulting shapes and frequencies agree well with finite element modal analyses of the plate

    Potential regulatory elements on PCDH7 gene affecting residual feed intake in Nelore cattle.

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    Editores: Luiz Lehmann Coutinho, ESALQ/USP; Luciana Correia de Almeida Regitano, Embrapa Pecuária Sudeste; Gerson Barreto Mourão, ESALQ/USP; Aline Silva Mello Cesar, ESALQ/USP; Bárbara Silva Vignato, FZEA/USP; Mirele Daiana Poleti, ESALQ/USP; Wellison Jarles da Silva Diniz, UFSCar

    Co-expression network analysis identifies genes associated with iron content in bovine muscle.

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    Editores: Luiz Lehmann Coutinho, ESALQ/USP; Luciana Correia de Almeida Regitano, Embrapa Pecuária Sudeste; Gerson Barreto Mourão, ESALQ/USP; Aline Silva Mello Cesar, ESALQ/USP; Bárbara Silva Vignato, FZEA/USP; Mirele Daiana Poleti, ESALQ/USP; Wellison Jarles da Silva Diniz, UFSCar

    Identification of a pleiotropic locus for beef quality and feed efficiency in cattle using bi-trait genome-wide association analysis.

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    Editores: Luiz Lehmann Coutinho, ESALQ/USP; Luciana Correia de Almeida Regitano, Embrapa Pecuária Sudeste; Gerson Barreto Mourão, ESALQ/USP; Aline Silva Mello Cesar, ESALQ/USP; Bárbara Silva Vignato, FZEA/USP; Mirele Daiana Poleti, ESALQ/USP; Wellison Jarles da Silva Diniz, UFSCar

    LDHB gene has allele-specific expression in liver of Nelore cattle extremes for feed efficiency.

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    Editores: Luiz Lehmann Coutinho, ESALQ/USP; Luciana Correia de Almeida Regitano, Embrapa Pecuária Sudeste; Gerson Barreto Mourão, ESALQ/USP; Aline Silva Mello Cesar, ESALQ/USP; Bárbara Silva Vignato, FZEA/USP; Mirele Daiana Poleti, ESALQ/USP; Wellison Jarles da Silva Diniz, UFSCar

    FACT - The First G-APD Cherenkov Telescope: Status and Results

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    The First G-APD Cherenkov telescope (FACT) is the first telescope using silicon photon detectors (G-APD aka. SiPM). It is built on the mount of the HEGRA CT3 telescope, still located at the Observatorio del Roque de los Muchachos, and it is successfully in operation since Oct. 2011. The use of Silicon devices promises a higher photon detection efficiency, more robustness and higher precision than photo-multiplier tubes. The FACT collaboration is investigating with which precision these devices can be operated on the long-term. Currently, the telescope is successfully operated from remote and robotic operation is under development. During the past months of operation, the foreseen monitoring program of the brightest known TeV blazars has been carried out, and first physics results have been obtained including a strong flare of Mrk501. An instantaneous flare alert system is already in a testing phase. This presentation will give an overview of the project and summarize its goals, status and first results
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