123 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
Selfβconsistent modeling of the largeβscale distortions in the geomagnetic field during the 24β27 September 1998 major magnetic storm
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94715/1/jgra17531.pd
Positron-emission tomographyβbased staging reduces the prognostic impact of early disease progression in patients with follicular lymphoma
Background: Previous studies reported that early progression of disease (POD) after initial therapy predicted poor overall survival (OS) in patients with follicular lymphoma (FL). Here, we investigated whether pre-treatment imaging modality had an impact on prognostic significance of POD. Methods: In this retrospective study, we identified 1088 patients with grade IβIIIA FL; of whom, 238 patients with stage IIβIV disease were initially treated with rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP), and 346 patients were treated with rituximab-based chemotherapy. Patients (N = 484) from the FOLL05 study served as an independent validation cohort. We risk-stratified patients based on pre-treatment radiographic imaging (positron-emission tomography [PET] versus computed tomography [CT]) and early POD status using event-defining and landmark analyses. A competing risk analysis evaluated the association between early POD and histologic transformation. Results: In the discovery cohort, patients with POD within 24 months (PFS24) of initiating R-CHOP therapy had a 5-year OS of 57.6% for CT-staged patients compared with 70.6% for PET-staged patients. In the validation cohort, the 5-year OS for patients with early POD was 53.9% and 100% in CT- and PET-staged patients, respectively. The risk of histologic transformation in patients whose disease progressed within one year of initiating therapy was higher in CT-staged patients than in PET-staged patients (16.7% versus 6.3%, respectively), which was associated with a 9.7-fold higher risk of death. Conclusion: In FL, pre-treatment PET staging reduced the prognostic impact of early POD compared with CT staging. Patients with early POD and no histologic transformation have an extended OS with standard therapy
ΠΡΠΈΠΎΡ ΠΈΡΡΡΠ³ΠΈΡ ΠΎΡΠ°Π³ΠΎΠ²ΡΡ ΠΏΠΎΡΠ°ΠΆΠ΅Π½ΠΈΠΉ ΠΏΠ΅ΡΠ΅Π½ΠΈ
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%.ΠΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½Ρ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΡ Π»Π΅ΡΠ΅Π½ΠΈΡ 339 Π±ΠΎΠ»ΡΠ½ΡΡ
ΠΏΠΎΡΠ»Π΅ ΠΊΡΠΈΠΎΡ
ΠΈΡΡΡΠ³ΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΎΠΏΠ΅ΡΠ°ΡΠΈΠΉ Π½Π° ΠΏΠ΅ΡΠ΅Π½ΠΈ ΠΏΡΠΈ ΡΠ°Π·Π»ΠΈΡΠ½ΡΡ
ΠΎΡΠ°Π³ΠΎΠ²ΡΡ
ΠΏΠΎΡΠ°ΠΆΠ΅Π½ΠΈΡΡ
ΡΡΠΎΠ³ΠΎ ΠΎΡΠ³Π°Π½Π°. ΠΡΠΎΠ°Π½Π°Π»ΠΈΠ·ΠΈΡΠΎΠ²Π°Π½ ΠΎΠΏΡΡ ΠΏΡΠΈΠΌΠ΅Π½Π΅Π½ΠΈΡ Π² Ρ
ΠΈΡΡΡΠ³ΠΈΠΈ ΠΎΡΠ°Π³ΠΎΠ²ΡΡ
ΠΏΠΎΡΠ°ΠΆΠ΅Π½ΠΈΠΉ ΠΏΠ΅ΡΠ΅Π½ΠΈ ΠΎΡΠΈΠ³ΠΈΠ½Π°Π»ΡΠ½ΠΎΠΉ ΠΊΡΠΈΠΎΡ
ΠΈΡΡΡΠ³ΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΠ΅Ρ
Π½ΠΈΠΊΠΈ, ΡΠΎΠ·Π΄Π°Π½Π½ΠΎΠΉ Π² Π’ΠΎΠΌΡΠΊΠΎΠΌ Π³Π΅ΠΏΠ°ΡΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠΌ ΡΠ΅Π½ΡΡΠ΅. ΠΡΠΈΠΌΠ΅Π½Π΅Π½ΠΈΠ΅ ΠΈΠ½ΡΡΡΡΠΌΠ΅Π½ΡΠΎΠ² ΠΎΡΠΈΠ³ΠΈΠ½Π°Π»ΡΠ½ΠΎΠΉ ΠΊΠΎΠ½ΡΡΡΡΠΊΡΠΈΠΈ Π²ΠΎ Π²ΡΠ΅ΠΌΡ ΡΠ΅Π·Π΅ΠΊΡΠΈΠΈ ΠΏΠ΅ΡΠ΅Π½ΠΈ ΠΏΡΠΈΠ²ΠΎΠ΄ΠΈΡ ΠΊ ΡΠ½ΠΈΠΆΠ΅Π½ΠΈΡ ΠΈΠ½ΡΡΠ°ΠΎΠΏΠ΅ΡΠ°ΡΠΈΠΎΠ½Π½ΠΎΠΉ ΠΊΡΠΎΠ²ΠΎΠΏΠΎΡΠ΅ΡΠΈ Π΄ΠΎ 30β40%, Π° ΡΠ°ΠΊΠΆΠ΅ ΡΠΏΠΎΡΠΎΠ±ΡΡΠ²ΡΠ΅Ρ ΡΠΌΠ΅Π½ΡΡΠ΅Π½ΠΈΡ ΠΊΠΎΠ»ΠΈΡΠ΅ΡΡΠ²Π° ΡΠ΅ΡΠΈΠ΄ΠΈΠ²ΠΎΠ² Π·Π°Π±ΠΎΠ»Π΅Π²Π°Π½ΠΈΡ, ΠΏΠΎΡΠΊΠΎΠ»ΡΠΊΡ ΠΊΡΠΈΠΎΠ΄Π΅ΡΡΡΡΠΊΡΠΈΡ ΠΊΡΠ»ΡΡΠΈ ΠΏΠ΅ΡΠ΅Π½ΠΈ ΠΏΠΎΡΠ»Π΅ ΡΠ΅Π·Π΅ΠΊΡΠΈΠΈ Π²Π΅Π΄Π΅Ρ ΠΊ ΡΠ°Π·ΡΡΡΠ΅Π½ΠΈΡ ΠΎΡΡΠ°Π²Π»Π΅Π½Π½ΡΡ
ΡΡΠ°ΡΡΠΊΠΎΠ² ΠΏΠ°ΡΠ°Π·ΠΈΡΠ°ΡΠ½ΠΎΠΉ ΡΠΊΠ°Π½ΠΈ Π² Π·ΠΎΠ½Π΅ ΠΎΠΏΠ΅ΡΠ°ΡΠΈΠΈ. ΠΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠ΅ ΠΊΡΠΈΠΎΡ
ΠΈΡΡΡΠ³ΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΌΠ΅ΡΠΎΠ΄ΠΈΠΊ ΠΏΠΎΠ·Π²ΠΎΠ»ΡΠ΅Ρ ΡΠ½ΠΈΠ·ΠΈΡΡ ΡΠ°ΡΡΠΎΡΡ Π»Π΅ΡΠ°Π»ΡΠ½ΡΡ
ΠΈΡΡ
ΠΎΠ΄ΠΎΠ² Π΄ΠΎ 4,42%
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