6,847 research outputs found
TPA-induced activation of MAP kinase
AbstractThreonine and tyrosine residue phosphorylation of a 42 kDa protein identified as mitogen-activated protein kinase (MAP kinase) was stimulated in extracts from TPA-pretreated cells. It is further shown that TPA pretreatment leads to the enhancement of an activity that will induce reactivation of dephosphorylated/inactivated MAP kinase. This TPA-induced activity induces the threonine and tyrosine phosphorylation of p42 in extracts from unstimulated cells
Azimuthal and pseudo-rapidity correlations with strange particles at intermediate-p at RHIC
We present results on two-particle azimuthal correlations with strange
trigger particles (, , , ) associated with
unidentified charged particles %at intermediate in d+Au and Au+Au
collisions at = 200 GeV. We investigate, in detail, the
near-side associated yield as a function of centrality, and strangeness
content in the trigger particle to look for possible flavor and baryon/meson
differences. We compare our results to a fragmentation and recombination model,
where the study of -triggered correlations is used as a critical test
of the validity of the recombination picture.Comment: 4 pages, 3 figures, presented at the 19th International Conference on
Ultra-Relativistic Nucleus-Nucleus Collisions, "Quark Matter 2006", Shanghai,
China, November 14-20, 200
Intra-jet correlations of high- hadrons from STAR
Systematic measurements of pseudorapidity () and azimuthal
() correlations between high- charged hadrons in
=200 GeV Au+Au collisions are presented. An enhancement of
correlated yield at large on the near-side is observed. This
effect persists up to trigger 9 GeV/c, indicating that it
is associated with jet production. More detailed analysis suggests distinct
short-range and long-range components in the correlation.Comment: 4 pages, 5 figures, presented at the 19th International Conference on
Ultra-Relativistic Nucleus-Nucleus Collisions, "Quark Matter 2006", Shanghai,
China, November 14-20, 200
On evaluating parallel computer systems
A workshop was held in an attempt to program real problems on the MIT Static Data Flow Machine. Most of the architecture of the machine was specified but some parts were incomplete. The main purpose for the workshop was to explore principles for the evaluation of computer systems employing new architectures. Principles explored were: (1) evaluation must be an integral, ongoing part of a project to develop a computer of radically new architecture; (2) the evaluation should seek to measure the usability of the system as well as its performance; (3) users from the application domains must be an integral part of the evaluation process; and (4) evaluation results should be fed back into the design process. It is concluded that the general organizational principles are achievable in practice from this workshop
Jet-like correlations between Forward- and Mid- rapidity in p+p, d+Au and Au+Au collisions from STAR at 200 GeV
In this proceedings we present STAR measurements of two particle azimuthal
correlations between trigger particles at mid-rapidity ( 1) and
associated particles at forward rapidities (2.7 3.9) in p+p, d+Au
and Au+Au collisions at = 200 GeV. Two particle azimuthal
correlations between a mid-rapidity trigger particle and forward-rapidity
associated particles preferably probe large-x quarks scattered off small-x
gluons in RHIC collisions. Comparison of the separate d- and Au-side
measurements in d+Au collisions may potentially probe gluon saturation and the
presence of Color Glass Condensate. In Au+Au collisions quark energy loss can
be probed at large rapidities, which may be different from gluon energy loss
measured at mid-rapidity.Comment: Quark Matter 06 Conference proceedings, submitted to Journal of Phys.
Centrality dependence of the ratios and - a test of thermalization in Au+Au collisions at RHIC
We present the centrality dependence of the ratios and
measured in Au+Au collisions at GeV by the
STAR experiment at RHIC. The results are compared to measurements of other
identified particles and recombination model expectations in order to gain
insight into the partonic collectivity and possible thermalization of the
produced medium.Comment: 4 pages, 2 figures, Quark Matter 2006 conference proceeding
Physics with Identified Particles at STAR
New physics results with identified particles at STAR are presented.
Measurements at low address bulk properties of the collision, while those
at high address jet energy loss in the bulk matter produced. Between
these extremes, measurements at intermediate address the interplay
between jets and the bulk. We highlight: measurements of fluctuations as
a new, sensitive probe of the initial conditions and the equation of state;
correlations involving multi-strange particles, along with ratios of identified
particles to test coalescence as a mechanism of particle production at
intermediate ; three particle azimuthal correlation to search for conical
emission; and the energy and particle-type dependence of hadron production at
high to study quark and gluon jet energy loss.Comment: 9 pages, 7 figures. To appear in the proceedings of the 19th
International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions
(Quark Matter 2006), Shanghai, China, November 14-20, 200
Upsilon cross section in p+p collisions at STAR
The main focus of the heavy flavor program at RHIC is to investigate the
properties of the dense matter produced in heavy-ion collisions by studying its
effect on open heavy flavor and quarkonia production. This in turn requires a
detailed understanding of their production in elementary p+p collisions so that
the dense matter effects can be later unfolded. In this paper, we present the
first mid-rapidity cross section measurement of bottomonium at
GeV with the STAR experiment. We compare our results with perturbative QCD
calculations. A brief status on the study of charmonium in STAR is given.Comment: 4 pages, 4 figures. To appear in the proceedings of Quark Matter 2006
as a special issue of Journal of Physics G: Nuclear and Particle Physic
The first measurement of meson semi-leptonic decay contribution to non-photonic electrons at RHIC
We present the first measurement for the meson semi-leptonic decay
contribution to non-photonic electrons at RHIC using non-photonic electron
azimuthal correlations with charged hadrons in p+p collisions at GeV from STAR.Comment: 4 pages, 3 figures, Quark Matter 2006 Proceedings, to appear in J.
Phys.
Incident-energy and system-size dependence of directed flow
We present STAR's measurements of directed flow for charged hadrons in Au+Au
and Cu+Cu collisions at GeV and 62.4 GeV, as a
function of pseudorapidity, transverse momentum and centrality. We find that
directed flow depends on the incident energy, but not on the system size. We
extend the validity of limiting fragmentation hypothesis to different collision
systems.Comment: Quark Matter 2006 proceedings, 4 pages, 4 figures, submitted to J.
Phys.
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