886 research outputs found
The Importance of the Study of the Hemodynamics of the Uterine Tumors by the Method of Dopplerometry in the Two- and Three-dimensional Echography Modes for Differential Diagnostics of Simple, Proliferating Leiomyomas and Uterine Sarcomas (Review of Litera
The article analyzes modern literature data on the importance of studying the hemodynamics of uterine tumors with dopplerometry in two - and three - dimensional regimens of echography for differential diagnosis of simple proliferating leiomyomas and sarcomas of the uterus. It is shown that the differential diagnosis of benign and Malignant tumors using the dopplerometry is based on various features of the blood supply of these tumors. On the basis of the analysis of literature data, it was concluded that in the dopplerometry evaluation of benign, borderline and Malignant tumors of myometrium in the two-dimensional regime, there were differences in the localization of the detected vessels in the CDM regimen, in the rates of vascular blood flow and vascular resistance in pulse dopplerometry. For a simple leiomyoma, the absence of a central intra-node localization of blood vessels in the CDM regimen, a low rate of arterial and venous blood flow, as well as an average resistance of arterial blood flow in the regime of impulsive dopplerometry are most typical; in a leiomyoma with eating disorders, the absence of a central intra-node localization of blood vessels, a low rate of arterial and venous blood flow in combination with high arterial resistance were more often observed. For the proliferating leiomyoma, the central intra-node localization of the vessels and the average blood flow velocities with low and medium resistance are characteristic. For sarcoma of the uterus, there is abundant vascularization both around the periphery and in the center, high blood flow rates and low resistance. The authors emphasize that there is information about the low specificity of this gradation, since the detection of a central type of vascularization and low resistance values can be in simple myomatous nodes with edema, eating disorders and destruction, and leads to diagnostic errors and suspicion of Malignancy. In the three-dimensional dopplerometry mode for simple leiomyomas, low indices of volume perfusion indices were characteristic, and for proliferating leiomyomas and sarcomas of the uterus – high indices of volume perfusion indices exceeding those in the uterus as a whole.Based on the review of the literature, the authors concluded that the presently available echographic and dopplerometric two- and three-dimensional markers are characterized by high sensitivity, but very low specificity. The low specificity of the known ultrasonic and dopplerometric criteria combined with the rarity of cases of sarcoma in the uterus against the background of a large number of similar echographically and dopplerometrically leiomyomas lead to low diagnostic accuracy of ultrasound diagnostics. This situation requires a further continuation of the scientific search for differential diagnostic ultrasound criteria by leiomyomas and sarcomas of the uterus using modern technologies, including three-dimensional echography
Hopf Term for a Two-Dimensional Electron Gas
In this Comment on the paper by W. Apel and Yu. A. Bychkov, cond-mat/9610040
and Phys. Rev. Lett. 78, 2188 (1997), we draw attention to our prior
microscopic derivations of the Hopf term for various systems and to
shortcomings of the Apel-Bychkov derivation. We explain how the value of the
Hopt term prefactor is expressed in terms of a topological invariant
in the momentum space and the quantized Hall conductivity of the system. (See
also related paper cond-mat/9703195)Comment: RevTeX, 1 page, no figure
Exponential and power-law probability distributions of wealth and income in the United Kingdom and the United States
Lorenz curve, Gini coefficient, family income
Energy spectrum of graphene multilayers in a parallel magnetic field
We study the orbital effect of a strong magnetic field parallel to the layers
on the energy spectrum of the Bernal-stacked graphene bilayer and multilayers,
including graphite. We consider the minimal model with the electron tunneling
between the nearest sites in the plane and out of the plane. Using the
semiclassical analytical approximation and exact numerical diagonalization, we
find that the energy spectrum consists of two domains. In the low- and
high-energy domains, the semiclassical electron orbits are closed and open, so
the spectra are discrete and continuous, correspondingly. The discrete energy
levels are the analogs of the Landau levels for the parallel magnetic field.
They can be detected experimentally using electron tunneling and optical
spectroscopy. In both domains, the electron wave functions are localized on a
finite number of graphene layers, so the results can be applied to graphene
multilayers of a finite thickness.Comment: 11 pages, 13 figures. Added to v.2: Appendix A, Fig. 13, Refs.
[18-23]. V.3: minor stylistic corrections from the published versio
LABOR EDUCATION OF PRESCHOOL CHILDREN: RETROSPECTIVE ANALYSIS
В данной статье рассматриваются вопросы организации трудового воспитания детей дошкольного возраста от времён Киевской Руси до начала ХХ века. Доказано, что становлению вопросов трудового воспитания детей дошкольного возраста способствовали: труды отечественных (Владимир Мономах, И. Гизель, И. Посошков, Г. Сковорода, В. Одоевский, К. Ушинский, Л. Толстой, Е. Водовозова, К. Вентцель) педагогов, организация педагогических музеев, летних детских «колоний», клубов и детских площадок, проведение Киевским обществом народных детских садов выставки «Дошкольное воспитание» и «Детский труд», организация магазина «Дошкольное воспитание», массовый выпуск отечественной педагогической литературы, издание педагических журналов.Ключевые слова: трудовое воспитание, дети дошкольного возраста, организация, анализ, становление.This article is devoted to the issues of the organization of labor education of preschool children from the time of Kievan Rus to the beginning of the XXth century. It has been proved that the formation of questions about labor education of preschool children was facilitated by: works of native (Vladimir Monomakh, I. Gizel, I. Pososhkov, G. Skovoroda, V. Odoyevskiy, K. Ushynskiy, L. Tolstoy, Ye. Vodovozova, K. Ventsel) teachers, the organization of pedagogical museums, summer children «colonies», clubs and playgrounds, exhibitions «Preschool education» and «Children labor» made by the Kiev Society of Folk Kindergartens, the organization of the store «Preschool education», mass production of native pedagogical literature, publishing pedagogical magazines.Keywords: labor education, preschool children, organization, analysis, formation
Curie law, entropy excess, and superconductivity in heavy fermion metals and other strongly interacting Fermi liquids
Low-temperature thermodynamic properties of strongly interacting Fermi
liquids with fermion condensate are investigated. We demonstrate that the spin
susceptibility of these systems exhibits the Curie-Weiss law, and the entropy
contains a temperature-independent term. The excessive entropy is released at
the superconducting transition, enhancing the specific heat jump Delta C and
rendering it proportional to the effective Curie constant. The theoretical
results are favorably compared with the experimental data on the heavy fermion
metal CeCoIn5, as well as He-3 films.Comment: 4 pages, 2 figures. V.2: a reference added; minor changes as in the
published versio
Detecting D-Wave Pairing and Collective Modes in Fermionic Condensates with Bragg Scattering
We show how the appearance of d-wave pairing in fermionic condensates
manifests itself in inelastic light scattering. Specifically, we calculate the
Bragg scattering intensity from the dynamic structure factor and the spin
susceptibility, which can be inferred from spin flip Raman transitions. This
information provides a precise tool with which we can identify nontrivial
correlations in the state of the system beyond the information contained in the
density profile imaging alone. Due to the lack of Coulomb effects in neutral
superfluids, this is also an opportunity to observe the Anderson-Bogoliubov
collective mode
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