1,062 research outputs found
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
Elliptic flow fluctuations in Au+Au collisions at GeV
Please note that after these results were reported at Quark Matter 2006 and
posted on the preprint server it was found that what is reported here as
\textit{elliptic flow fluctuations}, should rather be taken as an upper limit
on the fluctuations. Further analysis has shown that fitting the multiplicity
dependence of the q-distribution does not enable one to disentangle non-flow
and fluctuations. The data from the q-vector distrubution does not, therefore,
exclude the case of zero fluctuations. The remainder of these proceedings we
leave as they were originally reported.Comment: Statements regarding disentangling non-flow and fluctuations by
examining the multiplicity dependence of the q-vector distributions are
retracted: data presented here on elliptic flow fluctuations should be taken
as an upper limit on the fluctuation
N=2 Supersymmetry and U(1)-Duality
Understanding the consequences of the E_{7(7)} duality on the UV properties
of N=8 supergravity requires unravelling when and how duality-covariant actions
can be constructed so as to accommodate duality-invariant counter-terms. For
non-supersymmetric abelian gauge theories exhibiting U(1)-duality, with and
without derivative couplings, it was shown that such a covariant construction
is always possible. In this paper we describe a similar procedure for the
construction of covariant non-linear deformations of U(1)-duality invariant
theories in the presence of rigid N=2 supersymmetry. This is a concrete step
towards studying the interplay of duality and extended supersymmetry.Comment: 20 page
Association of Hepcidin-25 with survival after kidney transplantation
Background Hepcidin is considered the master regulator of iron homoeostasis. Novel hepcidin antagonists have recently been introduced as potential treatment for iron-restricted anaemia. Meanwhile, serum hepcidin has been shown to be positively associated with cardiovascular disease and inversely with acute kidney injury. These properties may lead to contrasting effects, especially in renal transplant recipients (RTR), which are prone to cardiovascular diseases and graft failure. To date, the role of serum hepcidin in RTR is unknown. We, therefore, prospectively determined the association of serum hepcidin with risk of graft failure, cardiovascular mortality and all-cause mortality in RTR. Materials and methods Serum hepcidin was assessed in an extensively phenotyped RTR cohort by dual-monoclonal sandwich ELISA specific immunoassay. Statistical analyses were performed using univariate linear regression followed by stepwise backward linear regression. Cox proportional hazard regression models were performed to determine prospective associations. Results We included 561 RTR (age 51 +/- 12 years). Mean haemoglobin (Hb) was 8.6 +/- 1.0 mM. Median [IQR] serum hepcidin was 7.2 [3.2-13.4] ng/mL. Mean estimated glomerular filtration rate was 47 +/- 16 mL/min/ 1.73 m(2). In univariate Cox regression analyses, serum hepcidin was not associated with risk of graft failure, cardiovascular mortality or all-cause mortality. Notably, after adjustment for high sensitivity C-reactive protein and ferritin, serum hepcidin became negatively associated with all-cause mortality (hazard ratio 0.89; 95% confidence interval 0.80-0.99, P = 0.3). Conclusions In this study, we did not find an association between serum hepcidin and outcomes, that is graft failure, cardiovascular mortality or all-cause mortality. Based on our results, it is questionable whether serum hepcidin may be used to predict a beneficial effect of hepcidin antagonists
Patterns of variation in reproductive parameters in Eurasian lynx (Lynx lynx)
Detailed knowledge of the variation in demographic rates is central for our ability to understand the evolution of life history strategies and population dynamics, and to plan for the conservation of endangered species. We studied variation in reproductive output of 61 radio-collared Eurasian lynx females in four Scandinavian study sites spanning a total of 223 lynx-years. Specifically, we examined how the breeding proportion and litter size varied among study areas and age classes (2-year-old vs. >2-year-old females). In general, the breeding proportion varied between age classes and study sites, whereas we did not detect such variation in litter size. The lack of differences in litter sizes among age classes is at odds with most findings in large mammals, and we argue that this is because the level of prenatal investment is relatively low in felids compared to their substantial levels of postnatal care
u^{c}d^{c}d^{c}-Based Affleck-Dine Baryogenesis
We consider the possibility of a successful Affleck-Dine mechanism along the
u^c d^c d^c direction in R-parity symmetric extensions of the minimal
supersymmetric Standard Model (MSSM) which contain a gauge singlet superfield
phi. Such gauge singlets commonly occur in extensions of the MSSM, for example
in models which seek to account for neutrino masses. We consider a two scalar
Affleck-Dine mechanism, with the flat direction stabilized by a
non-renormalizible superpotential term of the form (lambda/M) phi udd ~
(lambda/M) phi psi^3, where psi corresponds to the gauge non-singlet flat
direction. We give approximate solutions of the scalar field equations of
motion which describe the evolution of the condensates and show that the final
baryon asymmetry in this case is suppressed relative to that expected from the
conventional single scalar Affleck-Dine mechanism, based on a superpotential
term of the form (lambda/(4M)) psi^4, by a factor
(m_{s}/(m_{phi}+m_{s}))^(1/2), where m_{s} is the soft supersymmetry breaking
scalar mass and m_{phi} is the supersymmetric phi mass. It is possible for the
model to generate a baryon asymmetry even in the limit of unbroken B-L, so long
as the gauge singlet condensate doesn't decay until after anomalous electroweak
B+L violation is out of equilibrium following the electroweak phase transition.
This condition is generally satisfied if all Dirac neutrino masses are less
than around 10keV. This class of Affleck-Dine models can, in principle,be
experimentally ruled out, for example by the observation of a Dirac mass for
the mu or tau neutrino significantly larger than around 10keV together with a
mostly Higgsino LSP.Comment: 34 pages, no figures. Final published versio
Gaps and opportunities in refractory status epilepticus research in children: A multi-center approach by the Pediatric Status Epilepticus Research Group (pSERG)
PURPOSE:
Status epilepticus (SE) is a life-threatening condition that can be refractory to initial treatment. Randomized controlled studies to guide treatment choices, especially beyond first-line drugs, are not available. This report summarizes the evidence that guides the management of refractory convulsive SE (RCSE) in children, defines gaps in our clinical knowledge and describes the development and works of the \u27pediatric Status Epilepticus Research Group\u27 (pSERG). METHODS:
A literature review was performed to evaluate current gaps in the pediatric SE and RCSE literature. In person and online meetings helped to develop and expand the pSERG network. RESULTS:
The care of pediatric RCSE is largely based on extrapolations of limited evidence derived from adult literature and supplemented with case reports and case series in children. No comparative effectiveness trials have been performed in the pediatric population. Gaps in knowledge include risk factors for SE, biomarkers of SE and RCSE, second- and third-line treatment options, and long-term outcome. CONCLUSION:
The care of children with RCSE is based on limited evidence. In order to address these knowledge gaps, the multicenter pSERG was established to facilitate prospective collection, analysis, and sharing of de-identified data and biological specimens from children with RCSE. These data will allow identification of treatment strategies associated with better outcomes and delineate evidence-based interventions to improve the care of children with SE
Measurement of the Branching Fraction for B- --> D0 K*-
We present a measurement of the branching fraction for the decay B- --> D0
K*- using a sample of approximately 86 million BBbar pairs collected by the
BaBar detector from e+e- collisions near the Y(4S) resonance. The D0 is
detected through its decays to K- pi+, K- pi+ pi0 and K- pi+ pi- pi+, and the
K*- through its decay to K0S pi-. We measure the branching fraction to be
B.F.(B- --> D0 K*-)= (6.3 +/- 0.7(stat.) +/- 0.5(syst.)) x 10^{-4}.Comment: 7 pages, 1 postscript figure, submitted to Phys. Rev. D (Rapid
Communications
Evidence for the Rare Decay B -> K*ll and Measurement of the B -> Kll Branching Fraction
We present evidence for the flavor-changing neutral current decay and a measurement of the branching fraction for the related
process , where is either an or
pair. These decays are highly suppressed in the Standard Model,
and they are sensitive to contributions from new particles in the intermediate
state. The data sample comprises
decays collected with the Babar detector at the PEP-II storage ring.
Averaging over isospin and lepton flavor, we obtain the branching
fractions and , where the
uncertainties are statistical and systematic, respectively. The significance of
the signal is over , while for it is .Comment: 7 pages, 2 postscript figues, submitted to Phys. Rev. Let
Study of e+e- --> pi+ pi- pi0 process using initial state radiation with BABAR
The process e+e- --> pi+ pi- pi0 gamma has been studied at a center-of-mass
energy near the Y(4S) resonance using a 89.3 fb-1 data sample collected with
the BaBar detector at the PEP-II collider. From the measured 3pi mass spectrum
we have obtained the products of branching fractions for the omega and phi
mesons, B(omega --> e+e-)B(omega --> 3pi)=(6.70 +/- 0.06 +/- 0.27)10-5 and
B(phi --> e+e-)B(phi --> 3pi)=(4.30 +/- 0.08 +/- 0.21)10-5, and evaluated the
e+e- --> pi+ pi- pi0 cross section for the e+e- center-of-mass energy range
1.05 to 3.00 GeV. About 900 e+e- --> J/psi gamma --> pi+ pi- pi0 gamma events
have been selected and the branching fraction B(J/psi --> pi+ pi- pi0)=(2.18
+/- 0.19)% has been measured.Comment: 21 pages, 37 postscript figues, submitted to Phys. Rev.
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