663 research outputs found
Molecular Genetics of T Cell Development
T cell development is guided by a complex set of transcription factors that act recursively, in different combinations, at each of the developmental choice points from T-lineage specification to peripheral T cell specialization. This review describes the modes of action of the major T-lineage-defining transcription factors and the signal pathways that activate them during intrathymic differentiation from pluripotent precursors. Roles of Notch and its effector RBPSuh (CSL), GATA-3, E2A/HEB and Id proteins, c-Myb, TCF-1, and members of the Runx, Ets, and Ikaros families are critical. Less known transcription factors that are newly recognized as being required for T cell development at particular checkpoints are also described. The transcriptional regulation of T cell development is contrasted with that of B cell development, in terms of their different degrees of overlap with the stem-cell program and the different roles of key transcription factors in gene regulatory networks leading to lineage commitment
Net Charge Fluctuations in Au + Au Interactions at sqrt(s_NN) = 130 GeV
Data from Au + Au interactions at sqrt(s_NN) = 130 GeV, obtained with the
PHENIX detector at RHIC, are used to investigate local net charge fluctuations
among particles produced near mid-rapidity. According to recent suggestions,
such fluctuations may carry information from the Quark Gluon Plasma. This
analysis shows that the fluctuations are dominated by a stochastic distribution
of particles, but are also sensitive to other effects, like global charge
conservation and resonance decays.Comment: 6 pages, RevTeX 3, 3 figures, 307 authors, submitted to Phys. Rev.
Lett. on 21 March, 2002. Plain text data tables for the points plotted in
figures for this and previous PHENIX publications are (will be made) publicly
available at http://www.phenix.bnl.gov/phenix/WWW/run/phenix/papers.htm
Event-by-event fluctuations in Mean and Mean in sqrt(s_NN) = 130 GeV Au+Au Collisions
Distributions of event-by-event fluctuations of the mean transverse momentum
and mean transverse energy near mid-rapidity have been measured in Au+Au
collisions at sqrt(s_NN) = 130 GeV at RHIC. By comparing the distributions to
what is expected for statistically independent particle emission, the magnitude
of non-statistical fluctuations in mean transverse momentum is determined to be
consistent with zero. Also, no significant non-random fluctuations in mean
transverse energy are observed. By constructing a fluctuation model with two
event classes that preserve the mean and variance of the semi-inclusive p_T or
e_T spectra, we exclude a region of fluctuations in sqrt(s_NN) = 130 GeV Au+Au
collisions.Comment: 10 pages, RevTeX 3, 7 figures, 4 tables, 307 authors, submitted to
Phys. Rev. C on 22 March 2002. Plain text data tables for the points plotted
in figures for this and previous PHENIX publications are (will be made)
publicly available at
http://www.phenix.bnl.gov/phenix/WWW/run/phenix/papers.htm
Flow Measurements via Two-particle Azimuthal Correlations in Au + Au Collisions at sqrt(s_NN) = 130 GeV
Two particle azimuthal correlation functions are presented for charged
hadrons produced in Au + Au collisions at RHIC sqrt(s_NN) = 130 GeV. The
measurements permit determination of elliptic flow without event-by-event
estimation of the reaction plane. The extracted elliptic flow values v_2 show
significant sensitivity to both the collision centrality and the transverse
momenta of emitted hadrons, suggesting rapid thermalization and relatively
strong velocity fields. When scaled by the eccentricity of the collision zone,
epsilon, the scaled elliptic flow shows little or no dependence on centrality
for charged hadrons with relatively low p_T. A breakdown of this epsilon
scaling is observed for charged hadrons with p_T > 1.0 GeV/c for the most
central collisions.Comment: 6 pages, RevTeX 3, 4 figures, 307 authors, submitted to Phys. Rev.
Lett. on 11 April 2002. Plain text data tables for the points plotted in
figures for this and previous PHENIX publications are (will be made) publicly
available at http://www.phenix.bnl.gov/phenix/WWW/run/phenix/papers.htm
Centrality Dependence of Charged Particle Multiplicity in Au-Au Collisions at sqrt(s_NN)=130 GeV
We present results for the charged-particle multiplicity distribution at
mid-rapidity in Au - Au collisions at sqrt(s_NN)=130 GeV measured with the
PHENIX detector at RHIC. For the 5% most central collisions we find
. The results,
analyzed as a function of centrality, show a steady rise of the particle
density per participating nucleon with centrality.Comment: 307 authors, 43 institutions, 6 pages, 4 figures, 1 table Minor
changes to figure labels and text to meet PRL requirements. One author added:
M. Hibino of Waseda Universit
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