717 research outputs found
On the influence of the magnetic field of the GSI experimental storage ring on the time-modulation of the EC-decay rates of the H-like mother ions
We investigate the influence of the magnetic field of the
Experimental storage ring (ESR) at GSI on the periodic time-dependence of the
orbital K-shell electron capture decay ) rates of the H--like heavy ions.
We approximate the magnetic field of the ESR by a uniform magnetic field.
Unlike the assertion by Lambiase et al., arXiv: 0811.2302 [nucl-th], we show
that a motion of the H-like heavy ion in a uniform magnetic field cannot be the
origin of the periodic time-dependence of the EC-decay rates of the H-like
heavy ions.Comment: 3 pages, 1 figur
First-principles modelling of molecular single-electron transistors
We present a first-principles method for calculating the charging energy of a
molecular single-electron transistor operating in the Coulomb blockade regime.
The properties of the molecule are modeled using density-functional theory, the
environment is described by a continuum model, and the interaction between the
molecule and the environment are included through the Poisson equation. The
model is used to calculate the charge stability diagrams of a benzene and
C molecular single-electron transistor
Extended Huckel theory for bandstructure, chemistry, and transport. II. Silicon
In this second paper, we develop transferable semi-empirical parameters for
the technologically important material, silicon, using Extended Huckel Theory
(EHT) to calculate its electronic structure. The EHT-parameters areoptimized to
experimental target values of the band dispersion of bulk-silicon. We obtain a
very good quantitative match to the bandstructure characteristics such as
bandedges and effective masses, which are competitive with the values obtained
within an orthogonal-tight binding model for silicon. The
transferability of the parameters is investigated applying them to different
physical and chemical environments by calculating the bandstructure of two
reconstructed surfaces with different orientations: Si(100) (2x1) and Si(111)
(2x1). The reproduced - and -surface bands agree in part
quantitatively with DFT-GW calculations and PES/IPES experiments demonstrating
their robustness to environmental changes. We further apply the silicon
parameters to describe the 1D band dispersion of a unrelaxed rectangular
silicon nanowire (SiNW) and demonstrate the EHT-approach of surface passivation
using hydrogen. Our EHT-parameters thus provide a quantitative model of
bulk-silicon and silicon-based materials such as contacts and surfaces, which
are essential ingredients towards a quantitative quantum transport simulation
through silicon-based heterostructures.Comment: 9 pages, 9 figure
Mistletoe treatment in cancer-related fatigue: a case report
Cancer-related fatigue (CRF) is a major and very common disabling condition in cancer patients. Treatment options do exist but have limited therapeutic effects. Mistletoe extracts are widely-used complementary cancer treatments whose possible impact on CRF has not been investigated in detail. A 36-year-old Swedish woman with a 10-year history of recurrent breast cancer, suffering from severe CRF, started complementary cancer treatment with mistletoe extracts. Over two and a half years a correspondence was observed between the intensity of mistletoe therapy and the fatigue. Mistletoe extracts seemed to have a beneficial, dose-dependent effect on CRF. Although such effect has also been noted in clinical studies, it has never been the subject of detailed investigation. More research should clarify these observations
Стратегії проповідницького дискурсу І. Галятовського: антропологічний аспект
How cells in developing organisms interpret the quantitative information contained in morphogen gradients is an open question. Here we address this question using a novel integrative approach that combines quantitative measurements of morphogen-induced gene expression at single-mRNA resolution with mathematical modelling of the induction process. We focus on the induction of Notch ligands by the LIN-3/EGF morphogen gradient during vulva induction in Caenorhabditis elegans. We show that LIN-3/EGF-induced Notch ligand expression is highly dynamic, exhibiting an abrupt transition from low to high expression. Similar transitions in Notch ligand expression are observed in two highly divergent wild C. elegans isolates. Mathematical modelling and experiments show that this transition is driven by a dynamic increase in the sensitivity of the induced cells to external LIN-3/EGF. Furthermore, this increase in sensitivity is independent of the presence of LIN-3/EGF. Our integrative approach might be useful to study induction by morphogen gradients in other systems
In-medium modification of the isovector pion-nucleon amplitude
We study the in-medium modification of the isovector pi N amplitude using a
non-linear representation of the sigma model but keeping the scalar degree of
freedom. We check that our result does not depend on the representation. We
discuss the connection with other approaches based on chiral perturbation
theory.Comment: 7 page
Preparation and magnetoresistance of Ag 2+x Se thin films deposited via Pulsed Laser Deposition
The preparation of Ag 2+x Se thin films with thicknesses between 4 nm and
3000 nm by pulsed laser deposition on single crystalline NaCl and MgO
substrates is reported. The films are perfectly dense and show a good lateral
uniformity with a small number of defects. The microstructure of the films
corresponds to a nanoparquet, being composed of two different phases of silver
selenide. One phase is identified as the Naumannite low temperature phase of
silver selenide, the structure of the other phase has not been reported in
detail before and probably represents a metastable phase. Silver-rich films
contain silver precipitates with typical sizes on the nanoscale. Their presence
and their size appears to be responsible for the large and linear
magnetoresistance effect of silver-rich silver selenide
Universal homodyne tomography with a single local oscillator
We propose a general method for measuring an arbitrary observable of a
multimode electromagnetic field using homodyne detection with a single local
oscillator. In this method the local oscillator scans over all possible linear
combinations of the modes. The case of two modes is analyzed in detail and the
feasibility of the measurement is studied on the basis of Monte-Carlo
simulations. We also provide an application of this method in tomographic
testing of the GHZ state.Comment: 12 pages, 5 figures (8 eps files
Precision spectroscopy of pionic 1s states of Sn nuclei and evidence for partial restoration of chiral symmetry in the nuclear medium
Deeply bound 1s states of in Sn were preferentially
observed using the Sn(,He) pion-transfer reaction under the recoil-free
condition. The 1s binding energies and widths were precisely determined, and
were used to deduce the isovector parameter of the s-wave pion-nucleus
potential to be . The observed enhancement
of over the free value ()
indicates a reduction of the chiral order parameter, , at the normal nuclear density, .Comment: 4 pages including 3 postscript figures, RevTeX 4 with multirow.sty,
submitted to Physical Review Letter
Self-homodyne tomography of a twin-beam state
A self-homodyne detection scheme is proposed to perform two-mode tomography
on a twin-beam state at the output of a nondegenerate optical parametric
amplifier. This scheme has been devised to improve the matching between the
local oscillator and the signal modes, which is the main limitation to the
overall quantum efficiency in conventional homodyning. The feasibility of the
measurement is analyzed on the basis of Monte-Carlo simulations, studying the
effect of non-unit quantum efficiency on detection of the correlation and the
total photon-number oscillations of the twin-beam state.Comment: 13 pages (two-column ReVTeX) including 21 postscript figures; to
appear on Phys. Rev.
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