465 research outputs found
A study on the evaluation of the geoid-quasigeoid separation term over Pakistan with a solution of first and second order height terms
Progress in finite temperature lattice QCD
I review recent progress in finite temperature lattice calculations,
including the determination of the transition temperature, equation of state,
screening of static quarks and meson spectral functions.Comment: 8 pages, LaTeX, uses iopart.cls, invited talk presented at
Strangeness in Quark Matter 2007 (SQM 2007), Levoca, Slovakia, June 24-29,
200
Inhomogeneous Superconductivity in Condensed Matter and QCD
Inhomogeneous superconductivity arises when the species participating in the
pairing phenomenon have different Fermi surfaces with a large enough
separation. In these conditions it could be more favorable for each of the
pairing fermions to stay close to its Fermi surface and, differently from the
usual BCS state, for the Cooper pair to have a non zero total momentum. For
this reason in this state the gap varies in space, the ground state is
inhomogeneous and a crystalline structure might be formed. This situation was
considered for the first time by Fulde, Ferrell, Larkin and Ovchinnikov, and
the corresponding state is called LOFF. The spontaneous breaking of the space
symmetries in the vacuum state is a characteristic feature of this phase and is
associated to the presence of long wave-length excitations of zero mass. The
situation described here is of interest both in solid state and in elementary
particle physics, in particular in Quantum Chromo-Dynamics at high density and
small temperature. In this review we present the theoretical approach to the
LOFF state and its phenomenological applications using the language of the
effective field theories.Comment: RevTex, 83 pages, 26 figures. Submitted to Review of Modern Physic
Thermal Dileptons at LHC
We predict dilepton invariant-mass spectra for central 5.5 ATeV Pb-Pb
collisions at LHC. Hadronic emission in the low-mass region is calculated using
in-medium spectral functions of light vector mesons within hadronic many-body
theory. In the intermediate-mass region thermal radiation from the Quark-Gluon
Plasma, evaluated perturbatively with hard-thermal loop corrections, takes
over. An important source over the entire mass range are decays of correlated
open-charm hadrons, rendering the nuclear modification of charm and bottom
spectra a critical ingredient.Comment: 2 pages, 2 figures, contributed to Workshop on Heavy Ion Collisions
at the LHC: Last Call for Predictions, Geneva, Switzerland, 14 May - 8 Jun
2007 v2: acknowledgment include
Relativistic Nucleus-Nucleus Collisions and the QCD Matter Phase Diagram
This review will be concerned with our knowledge of extended matter under the
governance of strong interaction, in short: QCD matter. Strictly speaking, the
hadrons are representing the first layer of extended QCD architecture. In fact
we encounter the characteristic phenomena of confinement as distances grow to
the scale of 1 fm (i.e. hadron size): loss of the chiral symmetry property of
the elementary QCD Lagrangian via non-perturbative generation of "massive"
quark and gluon condensates, that replace the bare QCD vacuum. However, given
such first experiences of transition from short range perturbative QCD
phenomena (jet physics etc.), toward extended, non perturbative QCD hadron
structure, we shall proceed here to systems with dimensions far exceeding the
force range: matter in the interior of heavy nuclei, or in neutron stars, and
primordial matter in the cosmological era from electro-weak decoupling (10^-12
s) to hadron formation (0.5 10^-5 s). This primordial matter, prior to
hadronization, should be deconfined in its QCD sector, forming a plasma (i.e.
color conducting) state of quarks and gluons: the Quark Gluon Plasma (QGP).Comment: 146 pages, 83 figure
Production in Relativistic Heavy Ion Collisions at GeV
We report the first observation of in
relativistic heavy ion collisions. The transverse momentum spectrum of
from central Au+Au collisions at
GeV is presented. The ratios of the yield
derived from these data to the yields of negative hadrons, charged kaons, and
mesons have been measured in central and minimum bias collisions and
compared with model predictions and comparable , , and
results. The data indicate no dramatic reduction of
production in relativistic heavy ion collisions despite expected losses due to
rescattering effects.Comment: 6 pages, 3 figures, To be published in PRC
Early collective expansion: Relativistic hydrodynamics and the transport properties of QCD matter
Relativistic hydrodynamics for ideal and viscous fluids is discussed as a
tool to describe relativistic heavy-ion collisions and to extract transport
properties of the quark-gluon plasma from experimentally measured hadron
momentum spectra.Comment: Review article, 54 pages, 25 figure
Nuclear astrophysics: the unfinished quest for the origin of the elements
Half a century has passed since the foundation of nuclear astrophysics. Since
then, this discipline has reached its maturity. Today, nuclear astrophysics
constitutes a multidisciplinary crucible of knowledge that combines the
achievements in theoretical astrophysics, observational astronomy,
cosmochemistry and nuclear physics. New tools and developments have
revolutionized our understanding of the origin of the elements: supercomputers
have provided astrophysicists with the required computational capabilities to
study the evolution of stars in a multidimensional framework; the emergence of
high-energy astrophysics with space-borne observatories has opened new windows
to observe the Universe, from a novel panchromatic perspective; cosmochemists
have isolated tiny pieces of stardust embedded in primitive meteorites, giving
clues on the processes operating in stars as well as on the way matter
condenses to form solids; and nuclear physicists have measured reactions near
stellar energies, through the combined efforts using stable and radioactive ion
beam facilities. This review provides comprehensive insight into the nuclear
history of the Universe and related topics: starting from the Big Bang, when
the ashes from the primordial explosion were transformed to hydrogen, helium,
and few trace elements, to the rich variety of nucleosynthesis mechanisms and
sites in the Universe. Particular attention is paid to the hydrostatic
processes governing the evolution of low-mass stars, red giants and asymptotic
giant-branch stars, as well as to the explosive nucleosynthesis occurring in
core-collapse and thermonuclear supernovae, gamma-ray bursts, classical novae,
X-ray bursts, superbursts, and stellar mergers.Comment: Invited Review. Accepted for publication in "Reports on Progress in
Physics" (version with low-resolution figures
Improved risk stratification of patients with atrial fibrillation: an integrated GARFIELD-AF tool for the prediction of mortality, stroke and bleed in patients with and without anticoagulation.
OBJECTIVES: To provide an accurate, web-based tool for stratifying patients with atrial fibrillation to facilitate decisions on the potential benefits/risks of anticoagulation, based on mortality, stroke and bleeding risks. DESIGN: The new tool was developed, using stepwise regression, for all and then applied to lower risk patients. C-statistics were compared with CHA2DS2-VASc using 30-fold cross-validation to control for overfitting. External validation was undertaken in an independent dataset, Outcome Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF). PARTICIPANTS: Data from 39 898 patients enrolled in the prospective GARFIELD-AF registry provided the basis for deriving and validating an integrated risk tool to predict stroke risk, mortality and bleeding risk. RESULTS: The discriminatory value of the GARFIELD-AF risk model was superior to CHA2DS2-VASc for patients with or without anticoagulation. C-statistics (95% CI) for all-cause mortality, ischaemic stroke/systemic embolism and haemorrhagic stroke/major bleeding (treated patients) were: 0.77 (0.76 to 0.78), 0.69 (0.67 to 0.71) and 0.66 (0.62 to 0.69), respectively, for the GARFIELD-AF risk models, and 0.66 (0.64-0.67), 0.64 (0.61-0.66) and 0.64 (0.61-0.68), respectively, for CHA2DS2-VASc (or HAS-BLED for bleeding). In very low to low risk patients (CHA2DS2-VASc 0 or 1 (men) and 1 or 2 (women)), the CHA2DS2-VASc and HAS-BLED (for bleeding) scores offered weak discriminatory value for mortality, stroke/systemic embolism and major bleeding. C-statistics for the GARFIELD-AF risk tool were 0.69 (0.64 to 0.75), 0.65 (0.56 to 0.73) and 0.60 (0.47 to 0.73) for each end point, respectively, versus 0.50 (0.45 to 0.55), 0.59 (0.50 to 0.67) and 0.55 (0.53 to 0.56) for CHA2DS2-VASc (or HAS-BLED for bleeding). Upon validation in the ORBIT-AF population, C-statistics showed that the GARFIELD-AF risk tool was effective for predicting 1-year all-cause mortality using the full and simplified model for all-cause mortality: C-statistics 0.75 (0.73 to 0.77) and 0.75 (0.73 to 0.77), respectively, and for predicting for any stroke or systemic embolism over 1 year, C-statistics 0.68 (0.62 to 0.74). CONCLUSIONS: Performance of the GARFIELD-AF risk tool was superior to CHA2DS2-VASc in predicting stroke and mortality and superior to HAS-BLED for bleeding, overall and in lower risk patients. The GARFIELD-AF tool has the potential for incorporation in routine electronic systems, and for the first time, permits simultaneous evaluation of ischaemic stroke, mortality and bleeding risks. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier for GARFIELD-AF (NCT01090362) and for ORBIT-AF (NCT01165710)
Neutron Capture Cross Sections of Zr and La: Probing Neutron Exposure and Neutron Flux in Red Giant Stars
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