14,033 research outputs found
Transient lateral photovoltaic effect in patterned metal-oxide-semiconductor films
The time dependent transient lateral photovoltaic effect has been studied
with us time resolution and with chopping frequencies in the kHz range, in
lithographically patterned 21 nm thick, 5, 10 and 20 um wide and 1500 um long
Co lines grown over naturally passivated p-type Si (100). We have observed a
nearly linear dependence of the transitorial response with the laser spot
position. A transitorial response with a sign change in the laser-off stage has
been corroborated by numerical simulations. A qualitative explanation suggests
a modification of the drift-diffusion model by including the in uence of a
local inductance. Our findings indicate that the microstructuring of position
sensitive detectors could improve their space-time resolution.Comment: 4 pages, 4 figure
Gravitational wave recoil in Robinson-Trautman spacetimes
We consider the gravitational recoil due to non-reflection-symmetric
gravitational wave emission in the context of axisymmetric Robinson-Trautman
spacetimes. We show that regular initial data evolve generically into a final
configuration corresponding to a Schwarzschild black-hole moving with constant
speed. For the case of (reflection-)symmetric initial configurations, the mass
of the remnant black-hole and the total energy radiated away are completely
determined by the initial data, allowing us to obtain analytical expressions
for some recent numerical results that have been appeared in the literature.
Moreover, by using the Galerkin spectral method to analyze the non-linear
regime of the Robinson-Trautman equations, we show that the recoil velocity can
be estimated with good accuracy from some asymmetry measures (namely the first
odd moments) of the initial data. The extension for the non-axisymmetric case
and the implications of our results for realistic situations involving head-on
collision of two black holes are also discussed.Comment: 9 pages, 6 figures, final version to appear in PR
Local superconducting density of states of ErNi2B2C
We present local tunnelling microscopy and spectroscopy measurements at low
temperatures in single crystalline samples of the magnetic superconductor
ErNi2B2C. The electronic local density of states shows a striking departure
from s-wave BCS theory with a finite value at the Fermi level, which amounts to
half of the normal phase density of states.Comment: 9 pages, 3 figure
THROES: a caTalogue of HeRschel Observations of Evolved Stars. I. PACS range spectroscopy
This is the first of a series of papers presenting the THROES (A caTalogue of
HeRschel Observations of Evolved Stars) project, intended to provide a
comprehensive overview of the spectroscopic results obtained in the
far-infrared (55-670 microns) with the Her- schel space observatory on
low-to-intermediate mass evolved stars in our Galaxy. Here we introduce the
catalogue of interactively reprocessed PACS (Photoconductor Array Camera and
Spectrometer) spectra covering the 55-200 microns range for 114 stars in this
category for which PACS range spectroscopic data is available in the Herschel
Science Archive (HSA). Our sample includes objects spanning a range of
evolutionary stages, from the asymptotic giant branch to the planetary nebula
phase, displaying a wide variety of chemical and physical properties. The
THROES/PACS catalogue is accessible via a dedicated web-based inter- face
(https://throes.cab.inta-csic.es/) and includes not only the science-ready
Herschel spectroscopic data for each source, but also complementary photometric
and spectroscopic data from other infrared observatories, namely IRAS (Infrared
Astronomical Satellite), ISO (Infrared Space Observatory) or AKARI, at
overlapping wavelengths. Our goal is to create a legacy-value Herschel dataset
that can be used by the scientific community in the future to deepen our
knowledge and understanding of these latest stages of the evolution of
low-to-intermediate mass stars.Comment: 38 page
Effects of low dose morphine on perceived sleep quality in patients with refractory breathlessness : a hypothesis generating study
© 2015 Asian Pacific Society of Respirology. Background and objective The management of chronic refractory breathlessness is one of the indications for regular low-dose (≤30 mg/24 h) oral sustained release morphine. Morphine may disrupt sleep in some conditions and improve sleep quality in others. This study aimed to determine any signal of regular, low-dose morphine on perceived sleep disruption due to breathlessness and perceived sleep quality. Methods This is a secondary analysis of data from 38 participants with refractory breathlessness (30 male; 33 with COPD) aged 76 ± 0.9 years who completed a double-blind, randomized, placebo-controlled, cross-over study in which they received 20 mg oral sustained release morphine daily and placebo for 4 days each. Participant ratings of sleep disruption due to breathlessness and perceived sleep quality were obtained daily throughout the 8-day trial. Results Perceived sleep disruption due to breathlessness over the 4-day period ranged between 13% and 32% of participants for placebo and 13% and 26% for morphine, decreasing by each day of the study during the morphine arm. Most participants reported 'very good' or 'quite good' sleep throughout the trial and were less likely to perceive poor sleep quality during the morphine arm (odds ratio = 0.55, 95% confidence interval: 0.34-0.88, P = 0.01). Participants who reported decreased breathlessness during the 4 days on morphine were also likely to report improved sleep quality with morphine (P = 0.039). Conclusion Four days of low-dose morphine improved perceived sleep quality in elderly participants with refractory breathlessness. Regular low-dose morphine targeted to reduce refractory breathlessness may yield associated benefits by reducing sleep disruption and improving sleep quality
Heat pumping in nanomechanical systems
We propose using a phonon pumping mechanism to transfer heat from a cold to a
hot body using a propagating modulation of the medium connecting the two
bodies. This phonon pump can cool nanomechanical systems without the need for
active feedback. We compute the lowest temperature that this refrigerator can
achieve.Comment: 4 pages, 1 figure, published versio
Seeing Star Formation Regions with Gravitational Microlensing
We qualitatively study the effects of gravitational microlensing on our view
of unresolved extragalactic star formation regions. Using a general
gravitational microlensing configuration, we perform a number of simulations
that reveal that specific imprints of the star forming region are imprinted,
both photometrically and spectroscopically, upon observations. Such
observations have the potential to reveal the nature and size of these star
forming regions, through the degree of variability observed in a monitoring
campaign, and hence resolve the star formation regions in distant galaxies
which are too small to be probed via more standard techniques.Comment: 7 pages, 8 figures, ApJ accepte
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