69 research outputs found
Application of a wavelet technique for the detection of earthquake signatures in the geomagnetic field
We developed an algorithm especially adapted to <i>single-station </i>wavelet detection of geomagnetic events, which precede or accompany the earthquakes. The detection problem in this situation is complicated by a great variability of earthquakes and accompanied phenomena, which aggravates finding characteristic features of the events. Therefore we chose to search for the characteristic features of both "disturbed" intervals (containing earthquakes) and "quiet" recordings. In this paper we propose an algorithm for solving the problem of detecting the presence of signals produced by an earthquake via analysis of its signature against the existing database of magnetic signals. To achieve this purpose, we construct the magnetic signature of certain earthquakes using the distribution of the energies among blocks, which consist of wavelet packet coefficients
Magnetically induced spin-dependent photoemission from p-GaAs(Cs,O) into vacuum
A spin-dependent emission of optically oriented electrons from p-GaAs(Cs,O)
into vacuum was experimentally observed in a magnetic field normal to the
surface. This phenomenon is explained within the model which takes into account
the jump in the electron g factor at the semiconductor-vacuum interface. Due to
this jump, the effective electron affinity on the semiconductor surface depends
on the mutual direction of optically oriented electron spins and the magnetic
field, resulting in the spin-dependent photoemission. It is demonstrated that
the observed effect can be used for the determination of spin diffusion length
in semiconductors.Comment: 7 pages, 6 figures, published versio
Controlling the spin orientation of photoexcited electrons by symmetry breaking
We study reflection of optically spin-oriented hot electrons as a means to
probe the semiconductor crystal symmetry and its intimate relation with the
spin-orbit coupling. The symmetry breaking by reflection manifests itself by
tipping the net-spin vector of the photoexcited electrons out of the light
propagation direction. The tipping angle and the pointing direction of the
net-spin vector are set by the crystal-induced spin precession, momentum
alignment and spin-momentum correlation of the initial photoexcited electron
population. We examine non-magnetic semiconductor heterostructures and
semiconductor/ferromagnet systems and show the unique signatures of these
effects.Comment: 4 pages, 3 figures, resubmitte
Kramers-Kronig constrained variational analysis of optical spectra
A universal method of extraction of the complex dielectric function
from
experimentally accessible optical quantities is developed. The central idea is
that is parameterized independently at each node of a
properly chosen anchor frequency mesh, while is
dynamically coupled to by the Kramers-Kronig (KK)
transformation. This approach can be regarded as a limiting case of the
multi-oscillator fitting of spectra, when the number of oscillators is of the
order of the number of experimental points. In the case of the normal-incidence
reflectivity from a semi-infinite isotropic sample the new method gives
essentially the same result as the conventional KK transformation of
reflectivity. In contrast to the conventional approaches, the proposed
technique is applicable, without readaptation, to virtually all types of
linear-response optical measurements, or arbitrary combinations of
measurements, such as reflectivity, transmission, ellipsometry {\it etc.}, done
on different types of samples, including thin films and anisotropic crystals.Comment: 10 pages, 7 figure
Terahertz radiation driven chiral edge currents in graphene
We observe photocurrents induced in single layer graphene samples by
illumination of the graphene edges with circularly polarized terahertz
radiation at normal incidence. The photocurrent flows along the sample edges
and forms a vortex. Its winding direction reverses by switching the light
helicity from left- to right-handed. We demonstrate that the photocurrent stems
from the sample edges, which reduce the spatial symmetry and result in an
asymmetric scattering of carriers driven by the radiation electric field. The
developed theory is in a good agreement with the experiment. We show that the
edge photocurrents can be applied for determination of the conductivity type
and the momentum scattering time of the charge carriers in the graphene edge
vicinity.Comment: 4 pages, 4 figure, additional Supplemental Material (3 pages, 1
figure
Криохирургия очаговых поражений печени
The results of cryosurgical treatment of 339 patients with various focal liver diseases are presented. The experience of using cryosurgical equipment designed and manufactured in the Tomsk Hepatological Center in the surgery of focal liver diseases is analyzed. The application of inventive instruments in the liver resection leads to a decrease in the intraoperative blood loss down to 30- 40% and favors the reduction of backsets, because the cryodestruction of liver stump after resection leads to the destruction of rest parts of parasitic tissue in the surgical zone. The use of cryosurgical techniques lowers the number of deaths down to 4.42%.Представлены результаты лечения 339 больных после криохирургических операций на печени при различных очаговых поражениях этого органа. Проанализирован опыт применения в хирургии очаговых поражений печени оригинальной криохирургической техники, созданной в Томском гепатологическом центре. Применение инструментов оригинальной конструкции во время резекции печени приводит к снижению интраоперационной кровопотери до 30—40%, а также способствует уменьшению количества рецидивов заболевания, поскольку криодеструкция культи печени после резекции ведет к разрушению оставленных участков паразитарной ткани в зоне операции. Использование криохирургических методик позволяет снизить частоту летальных исходов до 4,42%
Oncoplastic Breast Consortium consensus conference on nipple-sparing mastectomy.
Purpose
Indications for nipple-sparing mastectomy (NSM) have broadened to include the risk reducing setting and locally advanced tumors, which resulted in a dramatic increase in the use of NSM. The Oncoplastic Breast Consortium consensus conference on NSM and immediate reconstruction was held to address a variety of questions in clinical practice and research based on published evidence and expert panel opinion.
Methods
The panel consisted of 44 breast surgeons from 14 countries across four continents with a background in gynecology, general or reconstructive surgery and a practice dedicated to breast cancer, as well as a patient advocate. Panelists presented evidence summaries relating to each topic for debate during the in-person consensus conference. The iterative
process in question development, voting, and wording of the recommendations followed the modified Delphi methodology.
Results
Consensus recommendations were reached in 35, majority recommendations in 24, and no recommendations in the remaining 12 questions. The panel acknowledged the need for standardization of various aspects of NSM and immediate reconstruction. It endorsed several oncological contraindications to the preservation of the skin and nipple. Furthermore, it recommended inclusion of patients in prospective registries and routine assessment of patient-reported outcomes. Considerable heterogeneity in breast reconstruction practice became obvious during the conference.
Conclusions
In case of conflicting or missing evidence to guide treatment, the consensus conference revealed substantial disagreement in expert panel opinion, which, among others, supports the need for a randomized trial to evaluate the safest
and most efficacious reconstruction techniques
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