3,852 research outputs found
An atlas of line profile studies for SU UMa type cataclysmic variables
We present H-alpha line-profile analyses for the seven SU UMa type dwarf
novae AK Cnc, WX Cet, AQ Eri, VW Hyi, RZ Leo, TU Men, and HS Vir. All data sets
are treated in the same manner, applying a sequence of techniques for each
system. The basic ingredients of this sequence are the diagnostic diagram to
determine the zero point of the orbital phase, and Doppler tomography to
visualise the emission distribution. We furthermore introduce a new qualitative
way of to evaluate the Doppler fit, by comparing the line profile of the
reconstructed with the original spectrum in the form of the V/R plot. We
present the results of the analysis in the compact form of an atlas, allowing a
direct comparison of the emission distribution in our targets. Although most of
the data sets were not taken with the intention of a line-profile analysis, we
obtain significant results and are able to indicate the type of the additional
emission in these systems. Our objects should have in principle very similar
physical properties, i.e. they cover only a small range in orbital periods,
mass ratios, and mass-transfer rates. Nevertheless, we find a large variety of
phenomena both with respect to the individual systems and also within
individual data sets of the same object. This includes `canonical' additional
emission components from the secondary star and the bright spot, but also
emission from the leading side of the accretion disc.Comment: 20 pages, 25 figures, accepted for publication in A&A, figures have
been diminished in size and qualit
Psychosocial Aspects Associated with Pain Perception in Individuals Undergoing Coronary Surgery
Objectivo: Identificar os factores psicossociais que influenciam a percepção da dor pós-operatória em doentes submetidos a cirurgia de revascularização do miocárdio (CRM).
Material e Métodos: Estudo exploratório
correlacional de 91 doentes (71 homens e 20
mulheres) submetidos a CRM (pontagem
aortocoronária) por esternotomia. A idade
média era de 63,8 ± 9,6 anos (entre 39 e 84).
Foram utilizados os seguintes instrumentos:
Escala Analógica Visual às 24, 48 e 96 horas
do pós-operatório; Questionário de
Caracterização Demográfica; Mental Health
Inventory de 5 itens; Percepção de Saúde
Geral (SF-36); Escala de Expectativas de
Dor; Escala de Percepção de Apoio; Escala
de Expectativas de Auto-eficácia; Satisfação
com o tratamento, médicos e enfermeiros
(American Pain Society Questionnaire)
aplicados às 96 horas após a cirurgia.
Resultados: Os doentes que apresentaram
expectativas elevadas de dor, percepcionaram
maior apoio, apresentaram níveis elevados de
auto-eficácia para lidar com a dor ou, se
pertenciam ao sexo masculino, sentiram
menos dor. De igual modo, os doentes que
apresentaram melhor saúde mental,
percepcionaram a sua saúde como boa e os
doentes que expressaram maior satisfação
com o tratamento sentiram menos dor. A dor
não foi influenciada pela idade, grau de
escolaridade ou pela satisfação com a
conduta de médicos e enfermeiros.
Conclusão: Após as primeiras 48 horas do
pós-operatório, a experiência de dor é
influenciada por factores psicossociais, em particular pela expectativa de dor,
expectativa de auto-eficácia, apoio percebido, percepção da saúde geral, percepção de saúde mental e satisfação com o tratamento para a dor. Perante os resultados, evidencia-se a necessidade de conjugar conhecimentos no sentido de dar respostas mais alargadas e de carácter multidisciplinar no tratamento da dor pós-operatória em CRM devendo, a par de outros aspectos, focar-se na gestão das
expectativas dos doentes
Inducing charges and currents from extra dimensions
In a particular variant of Kaluza-Klein theory, the so-called induced-matter
theory (IMT), it is shown that any configuration of matter may be geometrically
induced from a five-dimensional vacuum space. By using a similar approach we
show that any distribution of charges and currents may also be induced from a
five-dimensional vacuum space. Whereas in the case of IMT the geometry is
Riemannian and the fundamental equations are the five-dimensional Einstein
equations in vacuum, here we consider a Minkowskian geometry and the
five-dimensional Maxwell equations in vacuum.Comment: 8 pages. Accepted for publication in Modern Physics Letters
The "K-Correction" for Irradiated Emission Lines in LMXBs: Evidence for a Massive Neutron Star in X1822-371 (V691 CrA)
We study the K-correction for the case of emission lines formed in the X-ray
illuminated atmosphere of a Roche lobe filling star. We compute the
K-correction as function of the mass ratio 'q' and the disc flaring angle
'alpha' using a compact binary code where the companion's Roche lobe is divided
into 10^5 resolution elements. We also study the effect of the inclination
angle in the results. We apply our model to the case of the neutron star
low-mass X-ray binary X1822-371 (V691 CrA), where a K-emission velocity
K_em=300 +-8 km/s has been measured by Casares et al. (2003). Our numerical
results, combined with previous determination of system parameters, yields
1.61Msun < M_NS < 2.32Msun and 0.44Msun < M_2 < 0.56Msun for the two binary
components(i. e. 0.24 < q < 0.27), which provide a compelling evidence for a
massive neutron star in this system. We also discuss the implications of these
masses into the evolutionary history of the binary.Comment: 6 pages, 5 figures. Accepted for publication in Ap
Predictors of the perceived risk of COVID-19 and adherence to confinement guidelines in the context of the COVID-19 pandemic
INTRODUCTION: Complete adherence to public health guidelines is essential to reduce the spread of COVID-19. Studies on the factors associated with increased/decreased adherence to these measures have the potential to inform public policies directed at increasing adherence, and thus helping to control the spread of the current pandemic. OBJECTIVES: This study aimed at assessing the demographic and psychosocial predictors of the perceived risk of the COVID-19 and adherence to confinement guidelines during the first mandatory lockdown in Portugal. METHODS: A convenience sample of 430 adults living in Portugal between March 19(th) and May 2(nd,) 2020 completed an online survey asking participants about the perceived risk of the COVID-19 and adherence to confinement guidelines. Participants also completed a sociodemographic questionnaire and measures of psychological function. Multiple regression analysis was performed. RESULTS: Teleworking and Risk and COVID-19 controllability were significant predictors of the perceived risk of COVID-19 as measured by the perceived risk of being infected with COVID-19. Teleworking participants and those perceiving COVID-19 as less controllable reported a higher perceived risk of being infected with COVID-19 than those who were not in telework and perceived COVID-19 as a controllable condition. Adherence to confinement guidelines was predicted by the mental health status and perceived risk of COVID-19. Participants who reported worse mental health status, who perceived COVID-19 as a dangerous condition, and who trusted the public health system reported greater adherence to confinement guidelines. CONCLUSIONS: The results of this study will be discussed considering their implications to public health policymaking to promote adherence to public health policies. DISCLOSURE: No significant relationships
Solvation of alkane and alcohol molecules. Energy contributions
In this work we conduct a systematic ab initio study of the solvation of small alkane, monoalcohol and diol molecules, in polar solvents with different properties. A choice of basis set suitable for the type of compounds under study is presented. The various components of the solvent–solute interaction and the cavitation energy are treated individually and their variation with chain length and introduction of hydroxy groups assessed. The use of solute molecules in which controlled changes are imposed allows for an estimation of the relative contributions, thus eliminating accidental error cancellation.Fundacão para a Ciência e Tecnologia SAPIENS POCTI/35415/QUI/200
Final State Interactions and CP Violation in
Using chiral perturbation theory we calculate the imaginary parts of the form factors that arise from and
rescattering. We discuss their influence on CP violating variables in .Comment: ; 12 pages, 2 figures, TeX format; uses epsf.tex, tables.tex, and
phyzzx.te
Effective field theory and the quark model
We analyze the connections between the quark model (QM) and the description
of hadrons in the low-momentum limit of heavy-baryon effective field theory in
QCD. By using a three-flavor-index representation for the effective baryon
fields, we show that the ``nonrelativistic'' constituent QM for baryon masses
and moments is completely equivalent through O(m_s) to a parametrization of the
relativistic field theory in a general spin--flavor basis. The flavor and spin
variables can be identified with those of effective valence quarks. Conversely,
the spin-flavor description clarifies the structure and dynamical
interpretation of the chiral expansion in effective field theory, and provides
a direct connection between the field theory and the semirelativistic models
for hadrons used in successful dynamical calculations. This allows dynamical
information to be incorporated directly into the chiral expansion. We find, for
example, that the striking success of the additive QM for baryon magnetic
moments is a consequence of the relative smallness of the non-additive
spin-dependent corrections.Comment: 25 pages, revtex, no figure
Psychosocial factors as predictors of quality of life in chronic Portuguese patients
BACKGROUND:
Chronic illnesses are diseases of long duration and generally of slow progression. They cause significant quality of life impairment. The aim of this study was to analyse psychosocial predictors of quality of life and of subjective well-being in chronic Portuguese patients.
METHODS:
Chronic disease patients (n = 774) were recruited from central Portuguese Hospitals. Participants completed self-reported questionnaires assessing socio-demographic, clinical, psychosocial and outcome variables: quality of life (HRQL) and subjective well-being (SWB). MANCOVA analyses were used to test psychosocial factors as determinants of HRQL and SWB.
RESULTS:
After controlling for socio-demographic and clinical variables, results showed that dispositional optimism, positive affect, spirituality, social support and treatment adherence are significant predictors of HRQL and SWB. Similar predictors of quality of life, such as positive affect, treatment adherence and spirituality, were found for subgroups of disease classified by medical condition.
CONCLUSIONS:
The work identifies psychosocial factors associated with quality of life. The predictors for the entire group of different chronic diseases are similar to the ones found in different chronic disease subgroups: positive affect, social support, treatment adherence and spirituality. Patients with more positive affect, additional social support, an adequate treatment adherence and a feel-good spirituality, felt better with the disease conditions and consequently had a better quality of life. This study contributes to understanding and improving the processes associated with quality of life, which is relevant for health care providers and chronic diseases support.This study was supported by a grant from the
Fundação para a Ciência e Tecnologia (PTDC/PSI/71635/2006, PTDC/PSI/
73175/2006, SFRH/PROTEC/49284/2008
Science and Technology Studies × Educational Studies: Critical and Creative Perspectives on the Future of STEM Education: Introduction
Belgium Herbarium image of Meise Botanic Garden
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