10,338 research outputs found

    Copper-binding motifs in catalysis, transport, detoxification and signaling

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    AbstractCopper is required for many biological processes but is toxic at high cellular concentrations, so levels in the cell must be strictly controlled. Copper-binding motifs have been identified and characterized in many proteins. The way in which copper is coordinated by these motifs is important for the transport and distribution of intracellular copper and for the effective functioning of copper-dependent enzymes

    Extension of multifactor dimensionality reduction for identifying multilocus effects in the GAW14 simulated data

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    The multifactor dimensionality reduction (MDR) is a model-free approach that can identify gene × gene or gene × environment effects in a case-control study. Here we explore several modifications of the MDR method. We extended MDR to provide model selection without crossvalidation, and use a chi-square statistic as an alternative to prediction error (PE). We also modified the permutation test to provide different levels of stringency. The extended MDR (EMDR) includes three permutation tests (fixed, non-fixed, and omnibus) to obtain p-values of multilocus models. The goal of this study was to compare the different approaches implemented in the EMDR method and evaluate the ability to identify genetic effects in the Genetic Analysis Workshop 14 simulated data. We used three replicates from the simulated family data, generating matched pairs from family triads. The results showed: 1) chi-square and PE statistics give nearly consistent results; 2) results of EMDR without cross-validation matched that of EMDR with 10-fold cross-validation; 3) the fixed permutation test reports false-positive results in data from loci unrelated to the disease, but the non-fixed and omnibus permutation tests perform well in preventing false positives, with the omnibus test being the most conservative. We conclude that the non-cross-validation test can provide accurate results with the advantage of high efficiency compared to 10-cross-validation, and the non-fixed permutation test provides a good compromise between power and false-positive rate

    Suboptimal light conditions influence source-sink metabolism during flowering

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    Reliance on carbohydrates during flower forcing was investigated in one early and one late flowering cultivar of azalea (Rhododendron simsii hybrids). Carbohydrate accumulation, invertase activity, and expression of a purported sucrose synthase gene (RsSUS) was monitored during flower forcing under suboptimal (natural) and optimal (supplemental light) light conditions, after a cold treatment (7 degrees C + dark) to break flower bud dormancy. Post-production sucrose metabolism and flowering quality was also assessed. Glucose and fructose concentrations and invertase activity increased in petals during flowering, while sucrose decreased. In suboptimal light conditions RsSUS expression in leaves increased as compared to optimal light conditions, indicating that plants in suboptimal light conditions have a strong demand for carbohydrates. However, carbohydrates in leaves were markedly lower in suboptimal light conditions compared to optimal light conditions. This resulted in poor flowering of plants in suboptimal light conditions. Post production flowering relied on the stored leaf carbon, which could be accumulated under optimal light conditions in the greenhouse. These results show that flower opening in azalea relies on carbohydrates imported from leaves and is source-limiting under suboptimal light conditions

    System-size scan of dihadron azimuthal correlations in ultra-relativistic heavy ion collisions

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    System-size dependence of dihadron azimuthal correlations in ultra-relativistic heavy ion collision is simulated by a multi-phase transport model. The structure of correlation functions and yields of associated particles show clear participant path-length dependences in collision systems with a partonic phase. The splitting parameter and root-mean-square width of away-side correlation functions increase with collision system size from 14^{14}N+14^{14}N to 197^{197}Au+197^{197}Au collisions. The double-peak structure of away-side correlation functions can only be formed in sufficient "large" collision systems under partonic phase. The contrast between the results with partonic phase and with hadron gas could suggest some hints to study onset of deconfinment.Comment: 8 pages, 4 figures, 1 table; Nucl. Phys. A (accepted

    Quantum Spectrum of Cherenkov Glue

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    Full quantum calculation of Cherenkov gluon radiation by quark and gluon currents and a Cherenkov decay of a gluon into a pair of Cherenkov gluons in transparent media is performed. Energy losses due to Cherenkov gluon radiation in high energy nuclear collisions are calculated. The angular distribution of the energy flow due to the radiation of Cherenkov gluons is analyzed.Comment: 10 pages, 9 figures, misprints and references corrected, version accepted to Nuclear Physics

    Correlators of Giant Gravitons from dual ABJ(M) Theory

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    We generalize the operators of ABJM theory, given by Schur polynomials, in ABJ theory by computing the two point functions in the free field and at finite (N1,N2)(N_1,N_2) limits. These polynomials are then identified with the states of the dual gravity theory. Further, we compute correlators among giant gravitons as well as between giant gravitons and ordinary gravitons through the corresponding correlators of ABJ(M) theory. Finally, we consider a particular non-trivial background produced by an operator with an R\cal R-charge of O(N2)O(N^2) and find, in presence of this background, due to the contribution of the non-planar corrections, the large (N1,N2)(N_1,N_2) expansion is replaced by 1/(N1+M)1/(N_1+M) and 1/(N2+M)1/(N_2+M) respectively.Comment: Latex, 32+1 pages, 2 figures, journal versio

    Inverse temporal contributions of the dorsal hippocampus and medial prefrontal cortex to the expression of long-term fear memories

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    Retrograde amnesia following disruptions of hippocampal function is often temporally graded, with recent memories being more impaired. Evidence supports the existence of one or more neocortical long-term memory storage/retrieval site(s). Neurotoxic lesions of the medial prefrontal cortex (mPFC) or the dorsal hippocampus (DH) were made 1 day or 200 days following trace fear conditioning. Recently encoded trace fear memories were most disrupted by DH lesions, while remotely encoded trace and contextual memories were most disrupted by mPFC lesions. These data strongly support the consolidation theory of hippocampus function and implicate the mPFC as a site of long-term memory storage/retrieval

    Minimal Model Holography for SO(2N)

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    A duality between the large N 't Hooft limit of the WD_N minimal model CFTs and a higher spin gravity theory on AdS3 is proposed. The gravity theory has massless spin fields of all even spins s=2,4,6,..., as well as two real scalar fields whose mass is determined by the 't Hooft parameter of the CFT. We show that, to leading order in the large N limit, the 1-loop partition function of the higher spin theory matches precisely with the CFT partition function.Comment: 21 pages, LaTe
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