1,198 research outputs found
Dynamical Mass Generation and Confinement in Maxwell-Chern-Simons Planar Quantum Electrodynamics
We study the non-perturbative phenomena of Dynamical Mass Generation and
Confinement by truncating at the non-perturbative level the Schwinger-Dyson
equations in Maxwell-Chern-Simons planar quantum electrodynamics. We obtain
numerical solutions for the fermion propagator in Landau gauge within the
so-called rainbow approximation. A comparison with the ordinary theory without
the Chern-Simons term is presented.Comment: 9 pages, 9 figures; prepared for the XIV Mexican School of Particles
and Fields, 4-12 November 2010, Morelia, Michoacan, Mexic
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fCCAC: functional canonical correlation analysis to evaluate covariance between nucleic acid sequencing datasets
Computational evaluation of variability across DNA or RNA sequencing datasets is a crucial step in genomic science, as it allows both to evaluate reproducibility of biological or technical replicates, and to compare different datasets to identify their potential correlations. Here we present fCCAC, an application of functional canonical correlation analysis to assess covariance of nucleic acid sequencing datasets such as chromatin immunoprecipitation followed by deep sequencing (ChIP-seq). We show how this method differs from other measures of correlation, and exemplify how it can reveal shared covariance between histone modifications and DNA binding proteins, such as the relationship between the H3K4me3 chromatin mark and its epigenetic writers and readers.This work was supported by the ERC starting grant Relieve-IMDs and core support grant from the Wellcome Trust and MRC to the Wellcome Trust – Medical Research Council Cambridge Stem Cell Institute
Chiral Symmetry Breaking and Confinement Beyond Rainbow-Ladder Truncation
A non-perturbative construction of the 3-point fermion-boson vertex which
obeys its Ward-Takahashi or Slavnov-Taylor identity, ensures the massless
fermion and boson propagators transform according to their local gauge
covariance relations, reproduces perturbation theory in the weak coupling
regime and provides a gauge independent description for dynamical chiral
symmetry breaking (DCSB) and confinement has been a long-standing goal in
physically relevant gauge theories such as quantum electrodynamics (QED) and
quantum chromodynamics (QCD). In this paper, we demonstrate that the same
simple and practical form of the vertex can achieve these objectives not only
in 4-dimensional quenched QED (qQED4) but also in its 3-dimensional counterpart
(qQED3). Employing this convenient form of the vertex \emph{ansatz} into the
Schwinger-Dyson equation (SDE) for the fermion propagator, we observe that it
renders the critical coupling in qQED4 markedly gauge independent in contrast
with the bare vertex and improves on the well-known Curtis-Pennington
construction. Furthermore, our proposal yields gauge independent order
parameters for confinement and DCSB in qQED3.Comment: 8 pages, 6 figure
Smoothening block rewards: How much should miners pay for mining pools?
The rewards a blockchain miner earns vary with time. Most of the time is
spent mining without receiving any rewards, and only occasionally the miner
wins a block and earns a reward. Mining pools smoothen the stochastic flow of
rewards, and in the ideal case, provide a steady flow of rewards over time.
Smooth block rewards allow miners to choose an optimal mining power growth
strategy that will result in a higher reward yield for a given investment. We
quantify the economic advantage for a given miner of having smooth rewards, and
use this to define a maximum percentage of rewards that a miner should be
willing to pay for the mining pool services.Comment: 15 pages, 1 figur
Differential expression and upregulation of interleukin-1alpha, interleukin-1beta and interleukin-6 by freshly isolated human small intestinal epithelial cells.
BACKGROUND: Small intestinal epithelial cells (SIEC) may contribute to local immune regulation. AIM: To examine production of interleukin (IL)-1alpha, IL-1beta and IL-6 by freshly isolated human SIEC. METHODS: IL-1alpha and IL-1beta mRNA in epithelial layers (EL) prepared from small intestine and in intestinal epithelial cell (EC) lines were examined by reverse transcription-polymerase chain reaction. IL-1alpha, IL-1beta and IL-6 protein expression by SIEC was examined by flow cytometry before and after activation with lipopolysaccharide and epithelial growth factor. RESULTS: IL-1alpha and IL-1beta mRNA was detected in EL and EC lines. Background expression of IL-1alpha and IL-1beta protein by SIEC was observed, which did not increase even following activation. IL-6 protein was expressed by SIEC, in a proportion that increased in two out of three samples following activation. CONCLUSIONS: IL-6 expression and the presence of IL-1alpha and IL-1beta mRNA suggest a role for SIEC in the regulation of local inflammation
A COMPARATIVE STUDY ON PRIVATE AND PUBLIC HIGH SCHOOLS’ PRINCIPAL LEADERSHIP AND ITS IMPACT TO THE STUDENTS ACHIEVEMENT IN MATHEMATICS, SCIENCE AND ENGLISH SUBJECTS
The study aims to understand the relationship between the principal’s leadership style of both public and private high school institutions and student's performance in Math, Science and English. Support was found in a Theoretical model: Principal leadership effects on student's learning growth in Mathematics (Dumay, Boonen, and Dame, 2013) which reinforces the relationship between principal leadership and student achievement.For this study, the researchers aim to focus on three hypotheses: identification of the difference between the teacher's perception of the principal leadership style between private and public high school; the effects of such leadership styles and variables to the student achievement in each of the three general subjects (Mathematics, English, and Science); the effects of the dominant characteristics to the student achievements in general. Fifty-three teachers, both from private and public institutions, were administered the Multifactor Leadership Questionnaire 5X-Short form (MLQ 5X-Short). This measured all nine leadership characteristics and identified which type of leadership was dominantly displayed by their principal, for each school type. The study also examined the self-assessment of the principals for each school type and compared it to the perceptions of the teachers towards their leadership styles.Most findings were consistent with existing literature. In addition, this study also identified several areas of further study. 
Cord blood Lin(-)CD45(-) embryonic-like stem cells are a heterogeneous population that lack self-renewal capacity.
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Human umbilical cord blood (hUCB) has been proposed to contain not only haematopoietic stem cells, but also a rare pluripotent embryonic-like stem cell (ELSc) population that is negative for hematopoietic markers (Lin(-)CD45(-)) and expresses markers typical of pluripotent cells. The aim of this work was to isolate, characterise and expand this ELSc fraction from hUCB, as it may provide a valuable cell source for regenerative medicine applications. We found that we could indeed isolate a Lin(-)CD45(-) population of small cells (3-10 µm diameter) with a high nucleus to cytoplasm ratio that expressed the stem cell markers CD34 and CXCR4. However, in contrast to some previous reports, this fraction was not positive for CD133. Furthermore, although these cells expressed transcripts typical of pluripotent cells, such as SOX2, OCT3/4, and NANOG, they were not able to proliferate in any of the culture media known to support stem cell growth that we tested. Further analysis of the Lin(-)CD45(-) population by flow cytometry showed the presence of a Lin(-)CD45(-)Nestin(+) population that were also positive for CD34 (20%) but negative for CXCR4. These data suggest that the Lin(-)CD45(-) stem cell fraction present in the cord blood represents a small heterogeneous population with phenotypic characteristics of stem cells, including a Lin(-)CD45(-)Nestin(+) population not previously described. This study also suggests that heterogeneity within the Lin(-)CD45(-) cell fraction is the likely explanation for differences in the hUCB cell populations described by different groups that were isolated using different methods. These populations have been widely called "embryonic-like stem cell" on the basis of their phenotypical similarity to embryonic stem cells. However, the fact they do not seem to be able to self-renew casts some doubt on their identity, and warns against defining them as "embryonic-like stem cell" at this stage.Anthony Nolan and the Great Ormond Street Hospital Charity for financial support. Cesar Alvarez-Gonzalez is a fellowship from Consejo Nacional de Ciencia y Tecnologia (CONACyT) and Instituto Jaliscience de la Juventud (IJJ); Mexico
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Proteomic analyses of Urine Exosomes reveal New Biomarkers of Diabetes in Pregnancy.
ObjectiveTo evaluate 24 hour urine exosome protein content changes among pregnant US subjects with diabetes and obesity during early pregnancy.MethodsThe exosome proteome content from 24 hour urine samples of pregnant subjects with gestational diabetes mellitus (GDM, N=8) and pre-gestational Type 2 diabetes (PGD, N = 10) were compared with control samples (CTRL, N = 10) obtained at week 20 of pregnancy. Differences in exosome protein load between groups was identified by liquid chromatography/mass spectrometry, analyzed by linear regression in negative binomial distribution, visualized in MetaboAnalyst (version 3.0), and validated by western immunoblotting.ResultsAt the 20th week of pregnancy, we identified 646, 734 and 856 proteins in exosomes from 24 hour urine samples of patients from the CTRL, GDM and PGD groups, respectively. S100 calcium binding protein A9, damage associated molecular pattern (DAMP) signal, was found to be significantly increased in both GDM and PGD subjects. In GDM subjects the peptide counts for S100A9 protein independently correlated with maternal obesity and macrosomia of the newborn infants. Early to late pregnancy developmental changes in the GDM group were shown to utilize pathways and protein expression levels differently from those in PGD or CTRL groups.ConclusionsUrinary exosome proteomic analysis non-invasively provides insights into maternal changes during diabetic pregnancy. Exosome biomarkers early in pregnancy can be potentially used to better understand pathophysiologic mechanisms of diabetes at a cellular level, and to distinguish between gestational and pre-gestational diabetes at the pathway level. This information can aid intervention efforts to improve pregnancy outcomes in women with diabetes
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