141 research outputs found
Role of interleukin-13 on the development of minimal change nephrotic syndrome - A novel animal model
Ph.DDOCTOR OF PHILOSOPH
Spin structure of heavy-quark hybrids
A unique feature of quantum chromodynamics (QCD), the theory of strong
interactions, is the possibility for gluonic degrees of freedom to participate
in the construction of physical hadrons, which are color singlets, in an
analogous manner to valence quarks. Hadrons with no valence quarks are called
glueballs, while hadrons where both gluons and valence quarks combine to form a
color singlet are called hybrids. The unambiguous identification of such states
among the experimental hadron spectrum has been thus far not possible.
Glueballs are particularly difficult to establish experimentally since the
lowest lying ones are expected to strongly mix with conventional mesons. On the
other hand, hybrids should be easier to single out because the set of quantum
numbers available to their lowest excitations may be exotic, i.e., not realized
in conventional quark-antiquark systems. Particularly promising for discovery
appear to be heavy hybrids, which are made of gluons and a
heavy-quark-antiquark pair (charm or bottom). In the heavy-quark sector
systematic tools can be used that are not available in the light-quark sector.
In this paper we use a nonrelativistic effective field theory to uncover for
the first time the full spin structure of heavy-quark hybrids up to
-terms in the heavy-quark-mass expansion. We show that such terms
display novel characteristics at variance with our consolidated experience on
the fine and hyperfine splittings in atomic, molecular and nuclear physics. We
determine the nonperturbative contributions to the matching coefficients of the
effective field theory by fitting our results to lattice-QCD determinations of
the charmonium hybrid spectrum and extrapolate the results to the bottomonium
hybrid sector where lattice-QCD determinations are still challenging.Comment: 10 pages, 3 figures. Updated version including the corrections in the
erratum of Journal version. Two additional operators included, figures and
analysis update
Development of teaching beliefs and the focus of change in the process of pre-service ESL teacher education
This study sets out to investigate how pre-serviceESLteachers shape their beliefs in the process of experimenting with new teaching methods introduced in the teacher education programme. A 4-year longitudinal study was conducted with four randomly selectedESLpre-service teachers. Their theoretical orientations ofESLinstruction were tracked at intervals through a protocol which consisted of i) descriptive accounts, ii) surveys, iii) lesson plan analysis, iv) lesson recording and v) interviews. Despite the fact that these 4 student teachers had shown different theoretical orientations in the protocols, they shared similar patterns of instructional practices in the Teaching Practicum. It was also found that the new teaching method practiced in the teacher education programme was re-conceptualised by these student teachers in the actual teaching context because of the strong influence of their personal agency beliefs
An Epstein-Barr virus–encoded microRNA targets PUMA to promote host cell survival
Epstein-Barr virus (EBV) is a herpesvirus associated with nasopharyngeal carcinoma (NPC), gastric carcinoma (GC), and other malignancies. EBV is the first human virus found to express microRNAs (miRNAs), the functions of which remain largely unknown. We report on the regulation of a cellular protein named p53 up-regulated modulator of apoptosis (PUMA) by an EBV miRNA known as miR-BART5, which is abundantly expressed in NPC and EBV-GC cells. Modulation of PUMA expression by miR-BART5 and anti–miR-BART5 oligonucleotide was demonstrated in EBV-positive cells. In addition, PUMA was found to be significantly underexpressed in ∼60% of human NPC tissues. Although expression of miR-BART5 rendered NPC and EBV-GC cells less sensitive to proapoptotic agents, apoptosis can be triggered by depleting miR-BART5 or inducing the expression of PUMA. Collectively, our findings suggest that EBV encodes an miRNA to facilitate the establishment of latent infection by promoting host cell survival
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