1,430 research outputs found
Converse Magnetoelectric Experiments on a Room Temperature Spirally Ordered Hexaferrite
Experiments have been performed to measure magnetoelectric properties of room
temperature spirally ordered Sr3Co2Fe24O41 hexaferrite slabs. The measured
properties include the magnetic permeability, the magnetization and the strain
all as a function of the electric field E and the magnetic intensity H. The
material hexaferrite Sr3Co2Fe24O41 exhibits broken symmetries for both time
reversal and parity. The product of the two symmetries remains unbroken. This
is the central feature of these magnetoelectric materials. A simple physical
model is proposed to explain the magnetoelectric effect in these materials.Comment: 6 pages, 5 figure
Magnetic fields generated by r-modes in accreting millisecond pulsars
In millisecond pulsars the existence of the Coriolis force allows the
development of the so-called Rossby oscillations (r-modes) which are know to be
unstable to emission of gravitational waves. These instabilities are mainly
damped by the viscosity of the star or by the existence of a strong magnetic
field. A fraction of the observed millisecond pulsars are known to be inside
Low Mass X-ray Binaries (LMXBs), systems in which a neutron star (or a black
hole) is accreting from a donor whose mass is smaller than 1 . Here we
show that the r-mode instabilities can generate strong toroidal magnetic fields
by inducing differential rotation. In this way we also provide an alternative
scenario for the origin of the magnetars.Comment: 6 pages, 3 figures, Proceedings conference "Theoretical Nuclear
Physics", Cortona October 200
Reduction of C-reactive protein and the use of anti-hypertensives
Inflammatory processes are increasingly recognized as important participants in the pathophysiology of hypertension and cardiovascular disease. Angiotensin II may be to a large degree responsible for triggering vascular inflammation by inducing oxidative stress, resulting in up-regulation of inflammatory mediators. Inflammatory markers such as C-reactive protein are increased in the blood of patients with hypertension and predict the development of cardiovascular disease. Moreover, C-reactive protein may be a pro-inflammatory molecule under certain circumstances. C-reactive protein and high blood pressure in combination have additional predictive value for cardiovascular outcomes, as they contribute as independent determinants of cardiovascular risk. Therapeutic intervention aimed to reduce vascular inflammation in hypertensive patients has been proposed. Recent lines of evidence suggest that lifestyle modification and pharmacological approaches may reduce blood pressure and inflammation in patients with hypertension. Antagonism of the renin-angiotensin system with the selective angiotensin receptor blockers may improve cardiovascular outcome beyond blood pressure control, by reducing vascular inflammation and remodeling
Differential neuropsychological profiles in Parkinsonian patients with or without vascular lesions.
The purpose of this study is to compare the neuropsychological profile of patients affected by parkinsonism and vascular lesions to that in patients with PD alone (PD) and to evaluate whether the brain vascular lesion load is associated with neuropsychological variables. Thirty-six nondemented patients
with parkinsonism were divided into 3 groups of 12 patients each, according to both clinical history and the presence of brain vascular lesions and/or dopaminergic denervation as revealed by magnetic resonance and dopamine transporter imaging, respectively. The first group had vascular lesions without
dopaminergic denervation (VP group); the second group had vascular lesions and dopaminergic denervation (DD) (VP+DD group); and the third group consisted of patients with dopaminergic denervation (PD group) without vascular lesions. All
patients underwent neurological and neuropsychological assessments. The groups differed in disease duration, age at onset, and cerebrovascular risk factors. The VP and VP+DD groups performed worse than the PD group on frontal/executive tasks. Regardless of the presence of dopaminergic denervation, cerebrovascular lesions in hemispheric white matter, basal ganglia, and cerebellum have an important effect in determining early onset and severity of cognitive impairment in patients with parkinsonism
Generation of strong magnetic fields by r-modes in millisecond accreting neutron stars: induced deformations and gravitational wave emission
Differential rotation induced by the r-mode instability can generate very
strong toroidal fields in the core of accreting, millisecond spinning neutron
stars. We introduce explicitly the magnetic damping term in the evolution
equations of the r-modes and solve them numerically in the Newtonian limit, to
follow the development and growth of the internal magnetic field. We show that
the strength of the latter can reach large values, G, in the
core of the fastest accreting neutron stars. This is strong enough to induce a
significant quadrupole moment of the neutron star mass distribution,
corresponding to an ellipticity |\epsilon_B}| \sim 10^{-8}. If the symmetry
axis of the induced magnetic field is not aligned with the spin axis, the
neutron star radiates gravitational waves. We suggest that this mechanism may
explain the upper limit of the spin frequencies observed in accreting neutron
stars in Low Mass X-Ray Binaries. We discuss the relevance of our results for
the search of gravitational waves.Comment: 11 pages, 8 figure
Detection and characterization of Phytophthora species infecting tomato in southern Italy by DNA-based methods.
Absence of anomalous interactions in the quantum theory of constrained charged particles in presence of electrical currents
The experimental progress in synthesizing low-dimensional nanostructures
where carriers are confined to bent surfaces has boosted the interest in the
theory of quantum mechanics on curved two-dimensional manifolds. It was
recently asserted that constrained electrically charged particles couple to a
term linear in A_3 M, where A_3 is the transversal component of the
electromagnetic vector potential and M the surface mean curvature, thereby
making a dimensional reduction procedure impracticable in the presence of
fields. Here we resolve this apparent paradox by providing a consistent general
framework of the thin-wall quantization procedure. We also show that the
separability of the equation of motions is not endangered by the particular
choice of the constraint imposed on the transversal fluctuations of the
wavefunction, which renders the thin-wall quantization procedure well-founded.
It can be applied without restrictions.Comment: 4 page
Noninvasive Evaluation of Abdominal Fat and Liver Changes Following Progressive Weight Loss in Severely Obese Patients Treated with Laparoscopic Gastric Bypass.
Metabolic and nutritional status changes after 10% weight loss in severely obese patients treated with laparoscopic surgery vs integrated medical treatment
Electronic Transport in the Oxygen Deficient Ferromagnetic Semiconducting TiO
TiO films were deposited on (100) Lanthanum aluminates
LaAlO substrates at a very low oxygen chamber pressure
mtorr employing a pulsed laser ablation deposition technique. In previous work,
it was established that the oxygen deficiency in these films induced
ferromagnetism. In this work it is demonstrated that this same oxygen
deficiency also gives rise to semiconductor titanium ion impurity donor energy
levels. Transport resistivity measurements in thin films of TiO
are presented as a function of temperature and magnetic field. Magneto- and
Hall- resistivity is explained in terms of electronic excitations from the
titanium ion donor levels into the conduction band.Comment: RevTeX4, Four pages, Four Figures in ^.eps forma
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