547 research outputs found

    Azimuthal correlation between the (pl,pXb)(\vec{p}_l,\vec{p}_{X_b}) and (pl,Pt)(\vec{p}_l,\vec{P}_t) planes in the semileptonic rest frame decay of a polarized top quark: An O(αs)O(\alpha_s) effect

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    The azimuthal correlation between the planes formed by the vectors (p,pXb)(\vec{p}_\ell,\vec{p}_{X_b}) and (p,Pt)(\vec{p}_\ell,\vec{P}_t) in the semileptonic rest frame decay of a polarized top quark t()Xb+l++νt(\uparrow) \to X_b + l^+ + \nu_\ell belongs to a class of polarization observables involving the top quark which vanish at the Born term level in the standard model. We determine the next--to--leading order QCD corrections to the afore-mentioned azimuthal correlation and compare the result to the corresponding contribution of a non--standard--model right--chiral quark current.Comment: latex, 12 pages with 2 figures in the text, typos removed,comment and references added, replaced with published versio

    On the direction of transcription of cloned genes in Neurospora crassa.

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    On the direction of transcription of cloned genes in Neurospora crassa

    Co-regulation of two tandem genes by one blue-light element in Neurospora crassa

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    Many genes of Neurospora crassa are regulated by blue light: al-1 (Schmidhauser et al. 1990 Mol. Cell. Biol. 10:5064-5070), al-2 (Lauter, Schmidhauser, Yanofsky, Russo unpublished), al-3 (Nelson et al. 1989 Mol. Cell. Biol. 9:1271-1276), bli-3, bli-4, bli-7, bli-13 (Sommer et al. 1989 NAR 17:5713-5723). For none of these genes are the blue light cis-regulatory sequences (blue-light elements, BE) known. Here we report the presence of such BE in front of bli-4

    On the state of Latin American states: approaching the bicentenary

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    Praca recenzowana / Peer-reviewed paperWhat is the actual condition of the state in Latin America? Each contributor to this volume has been invited to answer this question by writing an interpretative essay from a specifically suggested angle: the origins of the state; government and society; economic growth; society and economy; nation-building; the indigenous population; political culture; international relations etc. It was the contributors’ decision which particular states to focus on in order to best illuminate the issues involved. Our main focus in the volume is on outlining some of the processes concerning the state now, two hundred years since the first declarations of independence. Along the way, we tackle both theoretical and normative issues. All the contributors to this volume share a long-cultivated multidisciplinary research interest in Latin America but the volume also reflects our disagreement on what we take the state to be as well as on the prevailing situation in Latin America. Each chapter reflects the views of its author all the way down to his choice of British or American English. As a result all chapters reflect the authors’ views on the contemporary state of the State in Latin America, as well as – why not say it – the authors’ identities. The book is aimed primarily at academics and students of the humanities and social sciences

    On the Early History of Current Algebra

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    The history of Current Algebra is reviewed up to the appearance of the Adler-Weisberger sum rule. Particular emphasis is given to the role current algebra played for the historical struggle in strong interaction physics of elementary particles between the S-matrix approach based on dispersion relations and field theory. The question whether there are fundamental particles or all hadrons are bound or resonant states of one another played an important role in this struggle and is thus also regarded.Comment: 17 page

    Mutation analysis of BRCA1 and BRCA2 genes in Iranian high risk breast cancer families

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    Background: Telomerase is a ribonucleoprotein enzyme that synthesises telomeres after cell division and maintains chromosomal stability leading to cellular immortalization. Telomerase has been associated with negative prognostic indicators in some studies. The present study aims to detect any association between telomerase sub-units: hTERT and hTR and the prognostic indicators including tumour's size and grade, nodal status and patient's age. Methods: Tumour samples from 46 patients with primary invasive breast cancer and 3 patients with benign tumours were collected. RT-PCR analysis was used for the detection of hTR, hTERT, and PGM1 (as a housekeeping) genes expression. Results: The expression of hTR and hTERT was found in 31(67.4%) and 38 (82.6%) samples respectively. We observed a significant association between hTR gene expression and younger age at diagnosis (p = 0.019) when comparing patients ≤ 40 years with those who are older than 40 years. None of the benign tumours expressed hTR gene. However, the expression of hTERT gene was revealed in 2 samples. No significant association between hTR and hTERT expression and tumour's grade, stage and nodal status was seen. Conclusion: The expression of hTR and hTERT seems to be independent of tumour's stage. hTR expression probably plays a greater role in mammary tumourogenesis in younger women (≤ 40 years) and this may have therapeutic implications in the context of hTR targeting strategies

    Identification of a novel phosphorylation site in hepatitis C virus NS5A

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    Hepatitis C virus (HCV) NS5A protein is phosphorylated on multiple residues; however, despite extensive study, the precise identity of these sites has not been determined unambiguously. In this study, we have used a combination of immunoprecipitation and mass spectrometry to identify these phosphorylation sites. This analysis revealed the presence of a major phosphorylated residue within NS5A from the genotype 1b Con1 isolate – serine 249 (serine 2221 in polyprotein numbering). However, mutation of this residue (or the corresponding threonine in the JFH-1 isolate) to either a phosphomimetic (aspartate) or a phosphoablative (alanine) residue resulted in no phenotype. We conclude that phosphorylation of this residue, in the context of a highly culture-adapted HCV genome, does not play a role in either viral RNA replication or virus assembly. It is possible that it might be important in an aspect of virus biology that is not recapitulated faithfully in the Huh-7 cell-culture system

    Chiral corrections to the vector and axial couplings of quarks and baryons

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    We calculate chiral corrections to the semileptonic vector and axial quark coupling constants using a manifestly Lorentz covariant chiral quark approach up to order O(p4) in the two- and tree-flavor picture. These couplings are then used in the evaluation of the corresponding couplings which govern the semileptonic transitions between octet baryon states. In the calculation of baryon matrix elements we use a general ansatz for the spatial form of the quark wave function, without referring to a specific realization of hadronization and confinement of quarks in baryons. Matching the physical amplitudes calculated within our approach to the model-independent predictions of baryon chiral perturbation theory (ChPT) allows one to deduce the connection between our parameters and those of baryon ChPT.Comment: 28 pages, 4 figure
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