2,704 research outputs found
DIFFUSION QUASI ÉLASTIQUE
Dans une première partie, on rappelle les conditions cinématiques dans lesquelles sont étudiées les réactions de diffusion quasi élastique ainsi que l'approximation de l'impulsion qui est utilisée pour leur interprétation. On analyse ensuite dans quel sens ces expériences ont évolué dans les dernières années' Trois expériences récentes sont présentées et discutées. Deux concernent les sous-structures α étudiées par réaction (p, pα) à 157 MeV et 600 MeV. La dernière s'intéresse aux agrégats d, t et 3He obtenus par réaction (p, pϰ) à 75 MeV
A note on Hawking radiation via complex path analysis
As long as we neglect backreaction, the Hawking temperature of a given black
hole would not depend upon the parameters of the particle species we are
considering. In the semiclassical complex path analysis approach of Hawking
radiation, this has been verified by taking scalar and Dirac spinors separately
for different stationary spacetime metrics. Here we show, in a coordinate
independent way that, for an arbitrary spacetime with any number of dimensions,
the equations of motion for a Dirac spinor, a vector, spin- and
spin- fields reduce to Klein-Gordon equations in the WKB
semiclassical limit. We then obtain, under some suitable assumptions, the
complex solutions of those resulting scalar equations across the Killing
horizon of a stationary spacetime to get a coordinate independent expression
for the emission probability identical for all particle species. Finally we
consider some explicit examples to demonstrate the validity of that expression.Comment: 12 pages, v2; manuscript divided into sections, many discussions and
references adde
Postmortem Evaluation of Left Flank Laparoscopic Access in an Adult Female Giraffe (Giraffa camelopardalis)
There are still few reports of laparoscopy in megavertebrates. The giraffe (Giraffa camelopardalis) is the tallest land mammal, and the largest ruminant species. An 18-year-old multiparous female hybrid giraffe, weighing 650 kg, was euthanized for chronic health problems, and left flank laparoscopy was performed less than 30 minutes after death. Safe primary access was achieved under visualisation using an optical bladed trocar (Visiport Plus, Tyco healthcare UK Ltd) without prior abdominal insufflation. A left paralumbar fossa approach allowed access to the spleen, rumen, left kidney, and intestines, but did not allow access to the reproductive tract which in nongravid females is intrapelvic in nature
On the semiclassical treatment of Hawking radiation
In the context of the semiclassical treatment of Hawking radiation we prove
the universality of the reduced canonical momentum for the system of a massive
shell self gravitating in a spherical gravitational field within the Painlev\'e
family of gauges. We show that one can construct modes which are regular on the
horizon both by considering as hamiltonian the exterior boundary term and by
using as hamiltonian the interior boundary term. The late time expansion is
given in both approaches and their time Fourier expansion computed to reproduce
the self reaction correction to the Hawking spectrum.Comment: 18 pages, LaTeX, Corrected typo
Recurrent backpropagation networks receiver for modulated signals over noisy channels
Recurrent Backpropagation networks have been used to build up a neural receiver for GSM signals. The simulations have been carried out considering an AWGN channel corrupted by ISI, fading and Doppler. The experimental results show that the neural receiver performs better than a classic coherent one and it improves its performances when the number of training samples is increased
Imaging of biliary involvement in sarcoidosis: Computed tomography, magnetic resonance cholangiopancreatography, and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging findings
Sarcoidosis is a multisystem disease usually affecting the chest, hilar lymph nodes, and lungs, but can potentially involve any organ; therefore, its clinical presentation may vary. Hepato-biliary involvement is rare, and typically asymptomatic; however, it can lead to cirrhosis, and may require liver transplantation. In this report, we present a rare case of a patient affected by sarcoidosis with hepatobiliary involvement. He presented to our hospital complaining of dyspnea triggered by moderate efforts and oppressive thoracic discomfort. Chest X-ray showed multiple bilateral nodular opacities and enlargement of both hilar regions, confirmed by a subsequent total-body computed tomography scan and positron emission tomography, which also revealed cardiac, splenic, and hepatic involvement. Liver function was studied via gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging, and magnetic resonance cholangiopancreatography (MRCP) was also performed. The diagnosis of sarcoidosis was finally achieved via liver biopsy, revealing non-necrotizing granulomas in the periportal space. The patient was treated with prednisone per os, with regression of all lesions at all levels. Although other cases of biliary sarcoidosis have been described, this report provides a complete image set of Gd-EOB-DTPA-enhanced magnetic resonance and MRCP images that is lacking in the English literature, and which may be useful for diagnosis
Investigating genetic and phenotypic variability of queen bees: Morphological and reproductive traits
Comparison of quantification methods for the condensed tannin content of extracts of Pinus pinaster bark
Bark from Pinus Pinaster is an interesting source of polyphenolic natural
compounds, that can be used successful1y as total or partial replacement of
conventional phenolic resins. These compounds, among other applications, are
used as adhesives in the wood agglomerate industry. In this kind of application
some problems remain to be solved in order to obtain a Pine extract of
commercial value. It is necessary to optimise tije extraction procedure and
select a suitable method for the quantification of the tannin content of the bark.
In order to study these problems, the tannin extraction from the Pine bark was
tested with an alkaline solution (NaOH), and with a fractionation procedure
based on a sequence of an organic (ethanol) and aqueous extraction. The
phenolic content of each extract or fraction was evaluated by the FolinCiocalteu
colorimetric assay for total phenols and two procedures using the
Stiasny reaction: the gravimetric Stiasny method and the indirect colorimetric
procedure that uses the Folin-Ciocalteu reagent to evaluate the total phenols
present in the extract solution before and after it condenses with formaldehyde.
The yield value when the alkaline extraction is used is substantially higher
than the values obtained with organic or aqueous solutions. However, the
selectivity of the process is low. In fact, it was found that the alkaline extract
Formaldehyde Condensable Phenolic Material (FCPM) content represents 9596
% of the total phenols content of the extract but this fraction is only ~ 40 %
of the total mass of extract. So, the alkaline extract is relatively poor in
phenolic material, exhibiting a large variety of non-phenolic extractives. On
the other end, ethanol provides a very rich phenolic extract, in which 96 % of
total phenols are condensable with formaldehyde, but exhibits a relatively low
extraction yield. The aqueous extract presents the lowest extraction yield with
low content either in phenolic material as in FCPM, but, as most of the phenolics had already been extracted by the previous organic extraction,
especially the low molecular weight fractions, this result was predictable
From product dispensing to patient care: The role of the pharmacist in providing pharmaceutical care as part of an integrated disease management approach
During the past decade, the profession of pharmacy has changed dramatically. The Doctor of Pharmacy degree has replaced the Bachelor of Science degree as the first professional degree offered at most accredited U.S. pharmacy schools. Advanced clinical training is now a mainstay of pharmacy training, and this has enabled pharmacists to contribute to disease management efforts. In addition, technological improvements in prescription processing have afforded pharmacists more time to participate in disease management activities. This paper describes how the role of the pharmacist has changed and reviews the results of programs involving pharmacists as disease management providers in the areas of asthma, hypertension, diabetes, and hyperlipidemia. Pharmacists\u27 contributions in various practice settings are also discussed
The Case for Biological Quantum Computer Elements
An extension to vonNeumann's analysis of quantum theory suggests self-measurement is a fundamental process of Nature. By mapping the quantum computer to the brain architecture we will argue that the cognitive experience results from a measurement of a quantum memory maintained by biological entities. The insight provided by this mapping suggests quantum effects are not restricted to small atomic and nuclear phenomena but are an integral part of our own cognitive experience and further that the architecture of a quantum computer system parallels that of a conscious brain.
We will then review the suggestions for biological quantum elements in basic neural structures and address the de-coherence objection by arguing for a self-measurement event model of Nature. We will argue that to first order approximation the universe is composed of isolated self-measurement events which guaranties coherence. Controlled de-coherence is treated as the input/output interactions between quantum elements of a quantum computer and the quantum memory maintained by biological entities cognizant of the quantum calculation results.
Lastly we will present stem-cell based neuron experiments conducted by one of us with the aim of demonstrating the occurrence of quantum effects in living neural networks and discuss future research projects intended to reach this objective
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