1,612 research outputs found
Magnetoelectric properties of 500 nm Cr2O3 films
The linear magnetoelectric effect was measured in 500 nm Cr2O3 films grown by
rf sputtering on Al2O3 substrates between top and bottom thin film Pt
electrodes. Magnetoelectric susceptibility was measured directly by applying an
AC electric field and measuring the induced AC magnetic moment using
superconducting quantum interference device magnetometry. A linear dependence
of the induced AC magnetic moment on the AC electric field amplitude was found.
The temperature dependence of the magnetoelectric susceptibility agreed
qualitatively and quantitatively with prior measurements of bulk single
crystals, but the characteristic temperatures of the film were lower than those
of single crystals. It was also possible to reverse the sign of the
magnetoelectric susceptibility by reversing the sign of the magnetic field
applied during cooling through the N\'eel temperature. A competition between
total magnetoelectric and Zeeman energies is proposed to explain the difference
between film and bulk Cr2O3 regarding the cooling field dependence of the
magnetoelectric effect.Comment: accepted at Physical Review
Is \lq\lq Heavy Quark Damping Rate Puzzle'' in Hot QCD Really the Puzzle?
Within the framework of perturbative resummation scheme of Pisarski and
Braaten, the decay- or damping-rate of a moving heavy quark (muon) to leading
order in weak coupling in hot QCD (QED) is examined. Although, as is well
known, the conventionally-defined damping rate diverges logarithmically at the
infrared limit, shown is that no such divergence appears in the physically
measurable decay rate. The cancellation occurs between the contribution from
the \lq\lq real'' decay diagram and the contribution from the diagrams with
\lq\lq thermal radiative correction''.Comment: 13pages, OCU-PHYS-15
Finite-temperature reaction-rate formula: Finite volume system, detailed balance, limit, and cutting rules
A complete derivation, from first principles, of the reaction-rate formula
for a generic process taking place in a heat bath of finite volume is given. It
is shown that the formula involves no finite-volume correction. Through
perturbative diagrammatic analysis of the resultant formula, the
detailed-balance formula is derived. The zero-temperature limit of the formula
is discussed. Thermal cutting rules, which are introduced in previous work, are
compared with those introduced by other authors.Comment: 35pages (text) plus 4pages (figures
Dimensionality dependence of optical nonlinearity and relaxation dynamics in cuprates
Femtosecond pump-probe measurements find pronounced dimensionality dependence
of the optical nonlinearity in cuprates. Although the coherent two-photon
absorption (TPA) and linear absorption bands nearly overlap in both quasi-one
and two-dimensional (1D and 2D) cuprates, the TPA coefficient is one order of
magnitude smaller in 2D than in 1D. Furthermore, picosecond recovery of optical
transparency is observed in 1D cuprates, while the recovery in 2D involves
relaxation channels with a time scales of tens of picoseconds. The experimental
results are interpreted within the two-band extended Hubbard model.Comment: 10 pages, 4 figure
Different mechanics of snap-trapping in the two closely related carnivorous plants Dionaea muscipula and Aldrovanda vesiculosa
The carnivorous aquatic Waterwheel Plant (Aldrovanda vesiculosa L.) and the
closely related terrestrial Venus Flytrap (Dionaea muscipula SOL. EX J. ELLIS)
both feature elaborate snap-traps, which shut after reception of an external
mechanical stimulus by prey animals. Traditionally, Aldrovanda is considered as
a miniature, aquatic Dionaea, an assumption which was already established by
Charles Darwin. However, videos of snapping traps from both species suggest
completely different closure mechanisms. Indeed, the well-described snapping
mechanism in Dionaea comprises abrupt curvature inversion of the two trap
lobes, while the closing movement in Aldrovanda involves deformation of the
trap midrib but not of the lobes, which do not change curvature. In this paper,
we present the first detailed mechanical models for these plants, which are
based on the theory of thin solid membranes and explain this difference by
showing that the fast snapping of Aldrovanda is due to kinematic amplification
of the bending deformation of the midrib, while that of Dionaea unambiguously
relies on the buckling instability that affects the two lobes.Comment: accepted in Physical Review
PCR-based Landmark Unique Gene (PLUG) markers are a useful tool for comparative genomic analysis and BAC clone screening in wheat
Dissertação de mestrado em Psicologia Clínica e Saúde (Psicopatologia e Psicoterapia Dinâmica), apresentada à Faculdade de Psicologia e Ciências da Educação da Universidade de CoimbraOs pacientes infetados pelo VIH têm sido objeto de interesse por parte
dos profissionais de saúde mental pela dimensão do impacto psicológico do
diagnóstico, evolução da infeção e a vulnerabilidade destes sujeitos. Seja
como for, em traço de evolução da terapêutica, a infeção pelo vírus da
imunodeficiência humana (VIH) é, atualmente, uma doença tendencialmente
crónica.
Entre as perturbações mentais, a depressão é descrita como uma das
comorbidades mais frequentes nos indivíduos com VIH e que muitas vezes
passa despercebida. Acompanha-se de elevada morbilidade e apresenta um
impacto sócio-económico, sendo uma das causas mais frequentes de
suicídio. Para além da incapacidade que se vai instalando progressivamente,
os indivíduos são confrontados com o estigma social, carência de apoio
social e isolamento.
Neste sentido, este estudo foi realizado com o intuito de chamar a
atenção para a necessidade de intervenção psicoterapêutica com esta
população, através da exploração dos sintomas psicopatológicos mais
prevalentes (com especial destaque para a depressão e para a ideação
suicida), tendo em consideração a progressão da doença e a as caraterísticas
socio-demográficas.Patients infected with HIV have been the object of interest on the part
of mental health professionals due to the dimension of the psychological
impact of the diagnosis, the course of infection and the vulnerability of these
subjects. Anyway, in trait evolution of therapy, infection by the human
immunodeficiency virus (HIV) is currently a chronic disease.
Among mental disorders, depression is described as one of the most
frequent comorbidities in individuals infected with HIV and which often
goes unnoticed. It is accompanied by high morbidity and presents a socialeconomic
impact, being one of the most frequent causes of suicide. Beyond
the progressively established disability, individuals face social stigma, lack
of social support and isolation.
Thus, this study was conducted in order to draw attention to the need
for psychotherapeutic intervention among this population, through the
exploitation of the most prevalent psychopathological symptoms (with
special emphasis on depression and suicidal ideation), taking into account
the progression of this disease and the social-demographic characteristics
PCR-based Landmark Unique Gene (PLUG) markers are a useful tool for comparative genomic analysis and BAC clone screening in wheat
Pathological activation of KIT in metastatic tumors of acral and mucosal melanomas
ArticleINTERNATIONAL JOURNAL OF CANCER. 124(4):862-868 (2009)journal articl
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