3,678 research outputs found
Some clinical aspects of prolonged clinostatic hypokinesia
Attendant problems which arise with prolonged confinement of patients to bed are discussed. These disorders are of a hyperkinesic nature, and the symptoms are treated with pharmacological substances
The catalogue of the discrete sources in the declination range from -13 deg to -2 deg
The results of the discrete source measurements with declinations -13 deg or = delta or = -2 deg and right ascensions 0 sub h + 24 sub h are given and were obtained as part of the systematic decametric survey of the celestial sphere with the rotatiotelecope UTR-2. Three hundred sixteen sources were found in the given declination range, four of which were observed for the first time. The source coordinates measured in the survey were compared with those from the 4th Cambridge survey at 178 MHz and the Parkes survey at 408 MHz
Plasma dispersion of multisubband electron systems over liquid helium
Density-density response functions are evaluated for nondegenerate
multisubband electron systems in the random-phase approximation for arbitrary
wave number and subband index. We consider both quasi-two-dimensional and
quasi-one- dimensional systems for electrons confined to the surface of liquid
helium. The dispersion relations of longitudinal intrasubband and transverse
intersubband modes are calculated at low temperatures and for long wavelengths.
We discuss the effects of screening and two-subband occupancy on the plasmon
spectrum. The characteristic absorption edge of the intersubband modes is
shifted relatively to the single-particle intersubband separation and the
depolarization shift correction can be significant at high electron densities
Multiscale fluctuations in nuclear response
The nuclear collective response is investigated in the framework of a doorway
picture in which the spreading width of the collective motion is described as a
coupling to more and more complex configurations. It is shown that this
coupling induces fluctuations of the observed strength. In the case of a
hierarchy of overlapping decay channels, we observe Ericson fluctuations at
different scales. Methods for extracting these scales and the related lifetimes
are discussed. Finally, we show that the coupling of different states at one
level of complexity to some common decay channels at the next level, may
produce interference-like patterns in the nuclear response. This quantum effect
leads to a new type of fluctuations with a typical width related to the level
spacing.Comment: 34 Latex pages including 6 figures (submitted to Phys. Rev. C
A flaring X-ray pulsar in Dorado
A study of unusual gamma-ray bursts detected on March 5 and March 6, 1979 in the KONUS experiment on the Venera 11 and Venera 12 spacecraft shows their source to be flaring X-ray pulsar in Dorado
Preliminary results of a gamma-ray burst study in the Konus experiment on the Venera-11 and Venera-12 space probes
Twenty-one gamma-ray bursts and 68 solar flares in the hard X-ray range were detected on Venera-11 and Venera-12 space probes during the initial 50-day observation period. Major characteristics of the equipment used and preliminary data on the temporal structure and energy spectra of the gamma-ray bursts are considered. The pattern of gamma-ray burst frequency distribution vs. intensity, N(S), is established
Roles of Mitochondrial Dynamics under Stressful and Normal Conditions in Yeast Cells
Eukaryotic cells contain dynamic mitochondrial filaments: they fuse and divide. Here we summarize data on the protein machinery driving mitochondrial dynamics in yeast and also discuss the factors that affect the fusion-fission balance. Fission is a general stress response of cells, and in the case of yeast this response appears to be prosurvival. At the same time, even under normal conditions yeast mitochondria undergo continuous cycles of fusion and fission. This seems to be a futile cycle and also expensive from the energy point of view. Why does it exist? Benefits might be the same as in the case of sexual reproduction. Indeed, mixing and separating of mitochondrial content allows mitochondrial DNA to segregate and recombine randomly, leading to high variation in the numbers of mutations per individual mitochondrion. This opens a possibility for effective purifying selection-elimination of mitochondria highly contaminated by deleterious mutations. The beneficial action presumes a mechanism for removal of defective mitochondria. We argue that selective mitochondrial autophagy or asymmetrical distribution of mitochondria during cell division could be at the core of such mechanism
The afterglow and kilonova of the short GRB 160821B
GRB 160821B is a short duration gamma-ray burst (GRB) detected and localized
by the Neil Gehrels Swift Observatory in the outskirts of a spiral galaxy at
z=0.1613, at a projected physical offset of 16 kpc from the galaxy's center. We
present X-ray, optical/nIR and radio observations of its counterpart and model
them with two distinct components of emission: a standard afterglow, arising
from the interaction of the relativistic jet with the surrounding medium, and a
kilonova, powered by the radioactive decay of the sub-relativistic ejecta.
Broadband modeling of the afterglow data reveals a weak reverse shock
propagating backward into the jet, and a likely jet-break at 3.5 d. This is
consistent with a structured jet seen slightly off-axis while expanding into a
low-density medium. Analysis of the kilonova properties suggests a rapid
evolution toward red colors, similar to AT2017gfo, and a low nIR luminosity,
possibly due to the presence of a long-lived neutron star. The global
properties of the environment, the inferred low mass (M_ej < 0.006 Msun) and
velocities (v > 0.05 c) of lanthanide-rich ejecta are consistent with a binary
neutron star merger progenitor.Comment: 14 pages, 6 figures, MNRAS, in press. Moderate revision, added Figure
5 and X-ray data to Table
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