10,658 research outputs found
Relativistic linear stability equations for the nonlinear Dirac equation in Bose-Einstein condensates
We present relativistic linear stability equations (RLSE) for
quasi-relativistic cold atoms in a honeycomb optical lattice. These equations
are derived from first principles and provide a method for computing
stabilities of arbitrary localized solutions of the nonlinear Dirac equation
(NLDE), a relativistic generalization of the nonlinear Schr\"odinger equation.
We present a variety of such localized solutions: skyrmions, solitons,
vortices, and half-quantum vortices, and study their stabilities via the RLSE.
When applied to a uniform background, our calculations reveal an experimentally
observable effect in the form of Cherenkov radiation. Remarkably, the Berry
phase from the bipartite structure of the honeycomb lattice induces a
boson-fermion transmutation in the quasi-particle operator statistics.Comment: 6 pages, 3 figure
Radio Detection of Cosmic Ray Air Showers with Codalema
Studies of the radio detection of Extensive Air Showers is the goal of the
demonstrative experiment CODALEMA. Previous analysis have demonstrated that
detection around eV was achieved with this set-up. New results
allow for the first time to study the topology of the electric field associated
to EAS events on a event by event basis.Comment: 6 pages, 4 figures Proceedings of the Rencontres de Moriond, Very
High Energy Phenomena in the Universe, La Thuile, Italy (March 12-19, 2005
Radio Detection of Extensive Air Showers with CODALEMA
The principle and performances of the CODALEMA experimental device, set up to
study the possibility of high energy cosmic rays radio detection, are
presented. Radio transient signals associated to cosmic rays have been
identified, for which arrival directions and shower's electric field topologies
have been extracted from the antenna signals. The measured rate, about 1 event
per day, corresponds to an energy threshold around 5.10^16 eV. These results
allow to determine the perspectives offered by the present experimental design
for radiodetection of UHECR at a larger scale.Comment: 4 pages and 3 figures. To appear in the Proceedings of the 29th ICRC,
Pune (2005
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Clinicians' attitudes to depression in Europe: a pooled analysis of Depression Attitude Questionnaire findings
Background: Depression in primary care is common but under-recognized and suboptimally managed. Health professionals’ attitudes are likely to play an important part in their recognition and management of depression.
Objectives: To pool findings from studies using the Depression Attitude Questionnaire (DAQ) to provide greater detail of clinicians’ attitudes and the measure’s psychometric properties.
Methods: Electronic databases and grey literature were searched for relevant studies. Data from eligible studies were requested and pooled analysis conducted.
Results: Twenty studies were eligible and data were obtained from 12 of these involving GPs (n = 1543) and nurses (n = 984). Responses showed strong disagreement that depression is due to ageing or weakness. European GPs were more positive about depression treatments than UK GPs; nurses were more favourable about psychotherapy than GPs. UK GPs especially strongly opposed notions that depression is best managed by psychiatrists. Trends over time indicated increasing acknowledgement of psychological therapies and the nurse’s role in depression management. Factor analysis indicated that many DAQ items fitted weakly within an overall model. The most parsimonious solution involved two factors: a positive view of depression and its treatment response and professional confidence in depression management.
Conclusions: Individual DAQ items appear to measure key aspects of clinicians’ attitudes to depression, and item responses indicate important differences between professions and geographical settings as well as changes over time. There are problems with the DAQ as a scale: its internal consistency is weak, and several items appear specific to particular professions or service structures, indicating that this questionnaire should be revised
Radio Detection of Cosmic Ray Extensive Air Showers: present status of the CODALEMA experiment
Data acquisition and analysis for the CODALEMA experiment, in operation for
more than one year, has provided improved knowledge of the characteristics of
this new device. At the same time, an important effort has been made to develop
processing techniques for extracting transient signals from data containing
interference.Comment: september 200
Radiodetection of Cosmic Ray Extensive Air Showers
We present the characteristics and performance of a demonstration experiment
devoted to the observation of ultra high- energy cosmic ray extensive air
showers using a radiodetection technique. In a first step, one antenna narrowed
band filtered acting as trigger, with a 4 threshold above sky
background-level, was used to tag any radio transient in coincidence on the
antenna array. Recently, the addition of 4 particle detectors has allowed us to
observe cosmic ray events in coincidence with antennas
Wavelet signatures of -splitting of the Isoscalar Giant Quadrupole Resonance in deformed nuclei from high-resolution (p,p) scattering off Nd
The phenomenon of fine structure of the Isoscalar Giant Quadrupole Resonance
(ISGQR) has been studied with high energy-resolution proton inelastic
scattering at iThemba LABS in the chain of stable even-mass Nd isotopes
covering the transition from spherical to deformed ground states. A wavelet
analysis of the background-subtracted spectra in the deformed 146,148,150Nd
isotopes reveals characteristic scales in correspondence with scales obtained
from a Skyrme RPA calculation using the SVmas10 parameterization. A semblance
analysis shows that these scales arise from the energy shift between the main
fragments of the K = 0, 1 and K = 2 components.Comment: 7 pages, 6 figure
Isotopic Production Cross Sections in Proton-Nucleus Collisions at 200 MeV
Intermediate mass fragments (IMF) from the interaction of Al,
Co and Au with 200 MeV protons were measured in an angular range
from 20 degree to 120 degree in the laboratory system. The fragments, ranging
from isotopes of helium up to isotopes of carbon, were isotopically resolved.
Double differential cross sections, energy differential cross sections and
total cross sections were extracted.Comment: accepted by Phys. Rev.
Competing phases in the high field phase diagram of (TMTSF)ClO
A model is presented for the high field phase diagram of (TMTSF)ClO,
taking into account the anion ordering, which splits the Fermi surface in two
bands. For strong enough field, the largest metal-SDW critical temperature
corresponds to the N=0 phase, which originates from two intraband nesting
processes. At lower temperature, the competition between these processes puts
at disadvantage the N=0 phase vs. the N=1 phase, which is due to interband
nesting. A first order transition takes then place from the N=0 to N=1 phase.
We ascribe to this effect the experimentally observed phase diagrams.Comment: 5 pages, 3 figures (to appear in Phys. Rev. Lett.
Aspectos epidemiológicos da caprinocultura cearense.
0 desenvolvimento da caprinocultura na regiao Nordeste do Brasil é severamente afetado por inúmeros fatores, entre eles a alta incidência de doenças. Objetivou-se conhecer o atual manejo sanitário empregado e os problemas sanitarios existentes na opiniao do criador do Ceara. 0 trabalho foi realizado nas varias regiôes criadoras de caprinos de raças leiteiras, nativas ou sem raça definida. Foram selecionadas 127 propriedades onde se aplicou um questionario. A percentagem média de mortalidade de animais foi de 22,8% e 4,6% em jovens e adultos, respectivamente. Os sinais clinicos relatados, por ordem, foram: anemia e edema de barbela (81,9% dos criatórios), diarréia (78,7%), aborto (75,6%), pododermatite (67,7%), linfadenite (66,9%), ectoparasitoses (63,8%), mamite (51,2%), pneumonia (44,9%), lesões vesiculares de pele (35,4%), ceratoconjuntivite (29,1%), problemas de ordem nervosa (26,8%), malformaçao fetal (15%), criptorquidismo (11%), prolapso de vagina/utero (11%) e artrite (8,7%). Pode-se concluir que o manejo sanitario dos caprinos desses criatórios é precario, independente do tipo de exploraçao ou regime de criaçao, a mortalidade de animais, principalmente de jovens, é considerada alta. Mesmo em criatórios com exploraçao leiteira não existe uma preocupaçao rigorosa com higiene e qualidade do leite. Epidemiological aspects of the raising goat in Ceará State, Brazil. ABSTRACT - The development of the goat raising in the Northeastern region of Brazil is hardly affected by several factors, among them, the high incidence of illness. The aim of this study was to assess the adopted sanitary management and the healthy problems according to Ceara?s goat breeders. The work was carried out in many regions of dairy and native goat raising. There were selected 127 properties where a questionnaire was applied. Mean percentage of animals? mortality was 22.8 and 4.6% for young and adult, respectively. Reported clinical signs were: anemia and dewlap edema (81.9% of the properties), diarrhea (78.7%), abortion (75.6%), foot rot (67.7%), lymphadenitis (66.9%), external parasites (63.8%), mastitis (51.2%), pneumonia (44.9%), goat pox (35.4%), keratoconjunctivitis (29.1%), nervous disorders (26.8%), fetal malformation (15%), cryptorchidism (11%), uterus/vagina prolapsed (11%), arthritis (8.7%), foot and mouth disease (2.4%) and rabies (0.8%). It could be concluded that the goats? sanitary management of those properties is precarious, independently either the exploitation way or the raising regimen; the animals? mortality, especially the youngest ones, is considered high; and even in dairy properties there is a lack of rigid worry concerning about hygiene and milk quality
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