10,338 research outputs found
Copper-binding motifs in catalysis, transport, detoxification and signaling
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
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
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
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
N+N to Au+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
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
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
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 -charge of
and find, in presence of this background, due to the contribution of
the non-planar corrections, the large expansion is replaced by
and 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
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)
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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