356 research outputs found
Energy-Dependent Form Factors of the Optical Potential for Intermediate-Energy Protons from a Relativistic Model
This work was supported by the National Science Foundation Grant NSF PHY 78-22774 A02 & A03 and by Indiana Universit
Resonances and O-curves in Hamiltonian systems
We investigate the problem of the existence of trajectories asymptotic to
elliptic equilibria of Hamiltonian systems in the presence of resonances.Comment: 12 page
The generalized non-conservative model of a 1-planet system - revisited
We study the long-term dynamics of a planetary system composed of a star and
a planet. Both bodies are considered as extended, non-spherical, rotating
objects. There are no assumptions made on the relative angles between the
orbital angular momentum and the spin vectors of the bodies. Thus, we analyze
full, spatial model of the planetary system. Both objects are assumed to be
deformed due to their own rotations, as well as due to the mutual tidal
interactions. The general relativity corrections are considered in terms of the
post-Newtonian approximation. Besides the conservative contributions to the
perturbing forces, there are also taken into account non-conservative effects,
i.e., the dissipation of the mechanical energy. This dissipation is a result of
the tidal perturbation on the velocity field in the internal zones with
non-zero turbulent viscosity (convective zones). Our main goal is to derive the
equations of the orbital motion as well as the equations governing
time-evolution of the spin vectors (angular velocities). We derive the
Lagrangian equations of the second kind for systems which do not conserve the
mechanical energy. Next, the equations of motion are averaged out over all fast
angles with respect to time-scales characteristic for conservative
perturbations. The final equations of motion are then used to study the
dynamics of the non-conservative model over time scales of the order of the age
of the star. We analyze the final state of the system as a function of the
initial conditions. Equilibria states of the averaged system are finally
discussed.Comment: 37 pages, 13 figures, accepted to Celestial Mechanics and Dynamical
Astronom
Impact of early remission by induction therapy on allogeneic stem cell transplantation for acute myeloid leukemia with an intermediate risk karyotype in first complete remission
For patients with acute myeloid leukemia (AML) early achievement of remission during induction treatment is an important predictor for long-term outcome irrespective of the type of consolidation therapy employed. Here, we retrospectively examined the prognostic impact of early remission (ER) versus delayed remission (DR) in a cohort of 132 AML patients with an intermediate risk karyotype undergoing allogeneic stem cell transplantation (alloSCT) in first complete remission (CR1). In contrast to patients showing DR, patients achieving ER had a significantly higher 3-year overall survival (OS) and disease-free survival (DFS) of 76% versus 54% (p=0.03) and 76% versus 53% (p=0.03). Likewise, three years after alloSCT the cumulative incidence of relapse (CI-R) was significantly lower in the ER subgroup as compared to patients achieving DR, i.e. 10% versus 35% (p=0.004), whereas non-relapse mortality (NRM) did not differ significantly. Multivariate analysis identified DR as an independent prognosticator for an inferior DFS (HR 3.37, p=0.002) and a higher CI-R (HR 3.55, p=0.002). Taken together, these data may indicate that the rapid achievement of remission predicts a favorable outcome in patients with intermediate risk AML undergoing alloSCT in CR1. In turn, the adverse effect of DR may not be fully overcome by alloSCT
Pion-Production in Heavy-Ion Collisions at SIS energies
We investigate the production of pions in heavy-ion collisions in the energy
range of - GeV/A. The dynamics of the nucleus-nucleus collisions is
described by a set of coupled transport equations of the
Boltzmann-Uehling-Uhlenbeck type for baryons and mesons. Besides the
and the we also take into account nucleon resonances up to
masses of as well as -, - and -mesons. We study
in detail the influence of the higher baryonic resonances and the
-production channels () on the pion spectra in
comparison to data from collisions at GeV/A and
-data for at 1.0 GeV/A. We, furthermore, present a detailed
comparison of differential pion angular distributions with the BEVALAC data for
Ar + KCl at 1.8 GeV/A. The general agreement obtained indicates that the
overall reactions dynamics is well described by our novel transport approach.Comment: 31 pages, 18 figures (inlcuded), to appear in Z. Phys.
Microscopic Theory of Josephson Mesoscopic Constrictions
We present a microscopic theory for the d.c. Josephson effect in model
mesoscopic constrictions. Our method is based on a non-equilibrium Green
function formalism which allows for a self-consistent determination of the
order parameter profile along the constriction. The various regimes defined by
the different length scales (Fermi wavelength , coherence length
and constriction length ) can be analyzed, including the case
where all these lengths are comparable. For the case phase oscillations with spatial period can be
observed. In the case of solutions with a phase-slip center inside
the constriction can be found, in agreement with previous phenomenological
theories.Comment: 4 pages (RevTex 3.0), 3 postscript figures available upon request,
312456-C
The stochastic gravitational wave background from turbulence and magnetic fields generated by a first-order phase transition
We analytically derive the spectrum of gravitational waves due to
magneto-hydrodynamical turbulence generated by bubble collisions in a
first-order phase transition. In contrast to previous studies, we take into
account the fact that turbulence and magnetic fields act as sources of
gravitational waves for many Hubble times after the phase transition is
completed. This modifies the gravitational wave spectrum at large scales. We
also model the initial stirring phase preceding the Kolmogorov cascade, while
earlier works assume that the Kolmogorov spectrum sets in instantaneously. The
continuity in time of the source is relevant for a correct determination of the
peak position of the gravitational wave spectrum. We discuss how the results
depend on assumptions about the unequal-time correlation of the source and
motivate a realistic choice for it. Our treatment gives a similar peak
frequency as previous analyses but the amplitude of the signal is reduced due
to the use of a more realistic power spectrum for the magneto-hydrodynamical
turbulence. For a strongly first-order electroweak phase transition, the signal
is observable with the space interferometer LISA.Comment: 46 pages, 17 figures. Replaced with revised version accepted for
publication in JCA
Healthcare Workers Who Work With COVID-19 Patients Are More Physically Exhausted and Have More Sleep Problems
In this survey study of 7,208 Dutch healthcare workers, we investigate whether healthcare workers dealing with COVID-19 patients experience lower general health, more physical and mental exhaustion and more sleep problems than other healthcare workers. Additionally, we study whether there are differences in well-being within the group of healthcare workers working with COVID-19 patients, based on personal and work characteristics. We find healthcare workers who are in direct contact with COVID-19 patients report more sleep problems and are more physically exhausted than those who are not in direct contact with COVID-19 patients. Mental exhaustion and general health do not significantly differ between healthcare workers who are in direct contact with COVID-19 patients and those who are not. Among healthcare workers in direct contact with COVID-19 p
Electromagnetic probes
We introduce the seminal developments in the theory and experiments of
electromagnetic probes for the study of the dynamics of relativistic heavy ion
collisions and quark gluon plasma.Comment: 47 pages, 33 Figures; Lectures delivered by Dinesh K. Srivastava at
QGP Winter School (QGPWS08) at Jaipur, India, February 1-3, 200
Electromagnetic Probes
A review is presented of dilepton and real photon measurements in
relativistic heavy ion collisions over a very broad energy range from the low
energies of the BEVALAC up to the highest energies available at RHIC. The
dileptons cover the invariant mass range \mll = 0 - 2.5 GeV/c, i.e. the
continuum at low and intermediate masses and the light vector mesons, . The review includes also measurements of the light vector mesons
in elementary reactions.Comment: To be published in Landolt-Boernstein Volume 1-23A; 40 pages, 24
figures. Final version updated with small changes to the text, updated
references and updated figure
- âŠ