717 research outputs found
Columnar defects and vortex fluctuations in layered superconductors
We investigate fluctuations of Josephson-coupled pancake vortices in layered
superconductors in the presence of columnar defects. We study the
thermodynamics of a single pancake stack pinned by columnar defects and obtain
the temperature dependence of localization length, pinning energy and critical
current. We study the creep regime and compute the crossover current between
line-like creep and pancake-like creep motion. We find that columnar defects
effectively increase interlayer Josephson coupling by suppressing thermal
fluctuations of pancakes. This leads to an upward shift in the decoupling line
most pronounced around the matching field.Comment: 5 pages, REVTeX, no figure
Molecular dynamics simulation of the order-disorder phase transition in solid NaNO
We present molecular dynamics simulations of solid NaNO using pair
potentials with the rigid-ion model. The crystal potential surface is
calculated by using an \emph{a priori} method which integrates the \emph{ab
initio} calculations with the Gordon-Kim electron gas theory. This approach is
carefully examined by using different population analysis methods and comparing
the intermolecular interactions resulting from this approach with those from
the \emph{ab initio} Hartree-Fock calculations. Our numerics shows that the
ferroelectric-paraelectric phase transition in solid NaNO is triggered by
rotation of the nitrite ions around the crystallographical c axis, in agreement
with recent X-ray experiments [Gohda \textit{et al.}, Phys. Rev. B \textbf{63},
14101 (2000)]. The crystal-field effects on the nitrite ion are also addressed.
Remarkable internal charge-transfer effect is found.Comment: RevTeX 4.0, 11 figure
Emergency Department visits due to intoxications in a Dutch university hospital: Occurrence, characteristics and health care costs
Background: Intoxications with alcohol and drugs are common in the Emergency Department. This study aimed to describe the occurrence and characteristics of intoxications (alcohol, Drugs of Abuse (DOA), pharmaceutical and chemical) presented to the Emergency Department and the health care costs of these intoxications. Methods: This was a retrospective medical record study of all patients (≥ 16 years) who presented to the Emergency Department of an inner-city academic hospital in the Netherlands due to single or multiple intoxication(s) as the primary or secondary reason in the year 2016. An intoxication was reported as present if the attending physician described the intoxication in the patient's medical record. Results: A total of 783 patients were included, accounting for 3.2% of the adult Emergency Department population (age ≥ 16 year). In 30% more than one substance was used. Intoxications with alcohol, Drugs of Abuse and pharmaceuticals was reported in respectively 62%, 29% and 21% of the intoxicated patients. The mean costs per patient presenting with an intoxication to the Emergency Department was € 1,490. The mean costs per patient were highest for pharmaceutical intoxications (€ 2,980), followed by Drugs of Abuse (€ 1,140) and alcohol (€ 1,070). Conclusions: Intoxications among patients aged 16 years and older are frequently seen at the Emergency Department and are frequently caused by multiple substances. Alcohol is the most common intoxication. Substantial healthcare costs are involved. Therefore, this study suggests that further research into hazardous alcohol consumption and DOA abuse is warranted. Copyright
Effective damping in the Raman cooling of trapped ions
We present a method of treating the interaction of a single three-level ion
with two laser beams. The idea is to apply a unitary transformation such that
the exact transformed Hamiltonian has one of the three levels decoupled for all
values of the detunings. When one takes into account damping, the evolution of
the system is governed by a master equation usually obtained via adiabatic
approximation under the assumption of far-detuned lasers. To go around the
drawbacks of this technique, we use the same unitary transformation to get an
effective master equation.Comment: 15 pages, 5 figures. To appear in Optics Communication
Charge conservation and time-varying speed of light
It has been recently claimed that cosmologies with time dependent speed of
light might solve some of the problems of the standard cosmological scenario,
as well as inflationary scenarios. In this letter we show that most of these
models, when analyzed in a consistent way, lead to large violations of charge
conservation. Thus, they are severly constrained by experiment, including those
where is a power of the scale factor and those whose source term is the
trace of the energy-momentum tensor. In addition, early Universe scenarios with
a sudden change of related to baryogenesis are discarded.Comment: 4 page
Coherent phi and omega meson photoproduction from deuteron and non-diffractive channels
For coherent photoproduction of phi and omega mesons from deuteron at forward
angles, the isovector pi-exchange amplitude is strongly suppressed.
We show a possibility to study the non-diffractive channels associated with
the unnatural parity exchange in phi-photoproduction and with the baryon
resonance excitations in omega-photoproduction by measuring the spin
observables.Comment: 5 pages, 7 figure
A novel MECA3 region in human 3p21.3 harboring putative tumor suppressor genes and oncogenes
Aim of this article is to perform the detailed analysis of 3p (especially 3p21 region) to discover novel potential oncogenes and/or tumor suppressors
A novel MECA3 region in human 3p21.3 harboring putative tumor suppressor genes and oncogenes
Aim of this article is to perform the detailed analysis of 3p (especially 3p21 region) to discover novel potential oncogenes and/or tumor suppressors
Demonstration of a novel technique to measure two-photon exchange effects in elastic scattering
The discrepancy between proton electromagnetic form factors extracted using
unpolarized and polarized scattering data is believed to be a consequence of
two-photon exchange (TPE) effects. However, the calculations of TPE corrections
have significant model dependence, and there is limited direct experimental
evidence for such corrections. We present the results of a new experimental
technique for making direct comparisons, which has the potential to
make precise measurements over a broad range in and scattering angles. We
use the Jefferson Lab electron beam and the Hall B photon tagger to generate a
clean but untagged photon beam. The photon beam impinges on a converter foil to
generate a mixed beam of electrons, positrons, and photons. A chicane is used
to separate and recombine the electron and positron beams while the photon beam
is stopped by a photon blocker. This provides a combined electron and positron
beam, with energies from 0.5 to 3.2 GeV, which impinges on a liquid hydrogen
target. The large acceptance CLAS detector is used to identify and reconstruct
elastic scattering events, determining both the initial lepton energy and the
sign of the scattered lepton. The data were collected in two days with a
primary electron beam energy of only 3.3 GeV, limiting the data from this run
to smaller values of and scattering angle. Nonetheless, this measurement
yields a data sample for with statistics comparable to those of the
best previous measurements. We have shown that we can cleanly identify elastic
scattering events and correct for the difference in acceptance for electron and
positron scattering. The final ratio of positron to electron scattering:
for GeV and
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