5,529 research outputs found
Measuring Propagation Speed of Coulomb Fields
The problem of gravity propagation has been subject of discussion for quite a
long time: Newton, Laplace and, in relatively more modern times, Eddington
pointed out that, if gravity propagated with finite velocity, planets motion
around the sun would become unstable due to a torque originating from time lag
of the gravitational interactions.
Such an odd behavior can be found also in electromagnetism, when one computes
the propagation of the electric fields generated by a set of uniformly moving
charges. As a matter of fact the Li\'enard-Weichert retarded potential leads to
a formula indistinguishable from the one obtained assuming that the electric
field propagates with infinite velocity. Feyman explanation for this apparent
paradox was based on the fact that uniform motions last indefinitely.
To verify such an explanation, we performed an experiment to measure the
time/space evolution of the electric field generated by an uniformely moving
electron beam. The results we obtain on such a finite lifetime kinematical
state seem compatible with an electric field rigidly carried by the beam
itself.Comment: 23 pages, 15 figure
Possible mechanisms of electronic phase separation in oxide interfaces
LaAlO3/SrTiO3 ad LaTiO3/SrTiO3 interfaces are known to host a strongly
inhomogeneous (nearly) two-dimensional electron gas (2DEG). In this work we
present three unconventional electronic mechanisms of electronic phase
separation (EPS) in a 2DEG as a possible source of inhomogeneity in oxide
interfaces. Common to all three mechanisms is the dependence of some
(interaction) potential on the 2DEG's density. We first consider a mechanism
resulting from a sizable density-dependent Rashba spin-orbit coupling. Next, we
point out that an EPS may also occur in the case of a density-dependent
superconducting pairing interaction. Finally, we show that the confinement of
the 2DEG to the interface by a density-dependent, self-consistent electrostatic
potential can by itself cause an EPS.Comment: 4 pages and 4 figures, Proceedings of the International Conference
"Superstripes 2014", 25-31 July 2015, Erice, Ital
Some closure operations in Zariski-Riemann spaces of valuation domains: a survey
In this survey we present several results concerning various topologies that
were introduced in recent years on spaces of valuation domains
Impact of Demographic Features, Lifestyle, and Comorbidities on the Clinical Expression of Hypertrophic Cardiomyopathy.
No abstract
Chromosomal assignment of the ovine hairless (hr) gene by fluorescence in situ hybridization.
Congenital hypotrichosis in mammalian species consists
of partial or complete absence of a hair coat at
birth. Affected individuals having a partial hair coat
at birth may loose it subsequently.The aim of this paper was to physically map the
ovine hr gene using fluorescence in situ hybridization
(FISH).A preliminary study on an internet data bank
(http://www.informatics.jax.org) showed that the regions
of the hr gene on murine chromosome 14 and
human chromosome 8 present homology with ovine
chromosome 2
Sudden Death and Left Ventricular Involvement in Arrhythmogenic Cardiomyopathy
BACKGROUND: Arrhythmogenic cardiomyopathy (ACM) is an inherited heart muscle disorder characterized by myocardial fibrofatty replacement and an increased risk of sudden cardiac death (SCD). Originally described as a right ventricular disease, ACM is increasingly recognized as a biventricular entity. We evaluated pathological, genetic, and clinical associations in a large SCD cohort. METHODS: We investigated 5205 consecutive cases of SCD referred to a national cardiac pathology center between 1994 and 2018. Hearts and tissue blocks were examined by expert cardiac pathologists. After comprehensive histological evaluation, 202 cases (4%) were diagnosed with ACM. Of these, 15 (7%) were diagnosed antemortem with dilated cardiomyopathy (n=8) or ACM (n=7). Previous symptoms, medical history, circumstances of death, and participation in competitive sport were recorded. Postmortem genetic testing was undertaken in 24 of 202 (12%). Rare genetic variants were classified according to American College of Medical Genetics and Genomics criteria. RESULTS: Of 202 ACM decedents (35.4±13.2 years; 82% male), no previous cardiac symptoms were reported in 157 (78%). Forty-one decedents (41/202; 20%) had been participants in competitive sport. The adjusted odds of dying during physical exertion were higher in men than in women (odds ratio, 4.58; 95% CI, 1.54-13.68; P=0.006) and in competitive athletes in comparison with nonathletes (odds ratio, 16.62; 95% CI, 5.39-51.24; P<0.001). None of the decedents with an antemortem diagnosis of dilated cardiomyopathy fulfilled definite 2010 Task Force criteria. The macroscopic appearance of the heart was normal in 40 of 202 (20%) cases. There was left ventricular histopathologic involvement in 176 of 202 (87%). Isolated right ventricular disease was seen in 13%, isolated left ventricular disease in 17%, and biventricular involvement in 70%. Among whole hearts, the most common areas of fibrofatty infiltration were the left ventricular posterobasal (68%) and anterolateral walls (58%). Postmortem genetic testing yielded pathogenic variants in ACM-related genes in 6 of 24 (25%) decedents. CONCLUSIONS: SCD attributable to ACM affects men predominantly, most commonly occurring during exertion in athletic individuals in the absence of previous reported cardiac symptoms. Left ventricular involvement is observed in the vast majority of SCD cases diagnosed with ACM at autopsy. Current Task Force criteria may fail to diagnose biventricular ACM before death
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