Vacuum Einstein spaces with axial symmetry

Four classes of solutions are found to the equations Rαβ=-2σ;α σ;β and gαβ σ;αβ=0 in three-dimensional space with metric gαβdxαdxβ and signature (+ --), equivalent to the Einstein equations Rij=0 in a vacuum for the metric {Mathematical expression}. The metric ds2 assumes axial symmetry and symmetry with respect to the reflection {Mathematical expression}. © 1977 Plenum Publishing Corporation

Covariant construction of the symmetric energy-momentum tensor of vector and spinor fields in an orthogonal frame of reference

A covariant method is devised to construct the symmetric energy-momentum tensor for vector fields in an orthogonal frame of reference. The method is then used to construct the symmetric energy-momentum tensor for spinor fields. © 1997 Plenum Publishing Corporation

Covariant spinor derivative associated with arbitrary linear connectedness

A covariant spinor derivative is constructed in arbitrary reference frames and also in coordinates, with specified arbitrary linear connectedness. © 1999 Kluwer Academic/Plenum Publishers

Advancing models of best practice in academic governance and management in higher education institutions in Kazakhstan

This is a collaborative research project of Nazarbayev University Graduate School of Education (NUGSE) in partnership with the Graduate School of Education of University of Pennsylvania (PennGSE). The Project aims at studying how academic leaders at public and private institutions in Kazakhstan are preparing for greater institutional autonomy and encouraging innovation [1]

Space-times admitting a three-parameter similarity group

Spacetimes admitting a similarity group are considered. Amongst them, special attention is given to the 3-parameter ones. A classification of such spacetimes is given based on the Bianchi type of the similarity group $H_3$, and the general form of the metric is provided in each case assuming the orbits are non-null.Comment: Latex 17 pages. Error corrected in Class. Quant. Grav. 14(1997)1183-1205, gr-qc/960706

Comparison between SiN x :H and hydrogen passivation of electromagnetically casted multicrystalline silicon material

International audienceThis work intends to compare two different passivation methods for electromagnetically continuous pulling silicon (EMCP): remote plasma hydrogenation and remote plasma enhanced CVD of SiN followed by high-temperature sintering. All experiments are carried out on textured and non-textured EMCP samples from the same ingot. To check the effect of high-temperature diffusion on EMCP, a n +-emitter is formed on one group of the samples using POCl 3 diffusion. Passivation capabilities of both techniques are checked using measurements of minority carrier lifetime by means of microwave photoconductance decay mapping. Solar cells are made to compare lifetime measurement with cell parameters.

Hiatal hernia surgery: laparoscopic versus robotic approach?

Aim. Evaluate the advantages and disadvantages of laparoscopic and robot-assisted anti-reflux operations.General findings. Reflux esophagitis in the association with hiatal hernia on the third place in the structure of gastroenterological diseases. The development of minimally invasive surgical technologies has led to an increase in the number of laparoscopic and robot-assisted anti-reflux operations. The literature review includes 12 studies, the results of which were published from 2002 to 2020, with a total number of patients 1633. In most of them, when comparing laparoscopic and robot-assisted anti-reflux operations, the advantages of one or another technique were not revealed. In some studies, the high cost and duration of the operation were noted when using the da Vinci robotic surgical complex. Other studies have reported possible improvements in the treatment outcomes of patients with large or recurrent hiatal hernias due to the high precision of movement and improved visualization characteristic of therobot-assisted surgeries.Conclusion. It is necessary to conduct more researches on this problem to develop indications for the choice of a particular surgical approach, as well as to create a single transparent algorithm for the surgical treatment of patients with reflux esophagitis and hiatal hernia

Symmetries of Bianchi I space-times

All diagonal proper Bianchi I space-times are determined which admit certain important symmetries. It is shown that for Homotheties, Conformal motions and Kinematic Self-Similarities the resulting space-times are defined explicitly in terms of a set of parameters whereas Affine Collineations, Ricci Collineations and Curvature Collineations, if they are admitted, they determine the metric modulo certain algebraic conditions. In all cases the symmetry vectors are explicitly computed. The physical and the geometrical consequences of the results are discussed and a new anisitropic fluid, physically valid solution which admits a proper conformal Killing vector, is given.Comment: 19 pages, LaTex, Accepted for publication in Journal of Mathematical Physic

Possibilities of using raman spectroscopy in diagnosis of prostate cancer in vitro

diagnosis of "Benign prostatic hyperplasia" (BPH). 47 prostate tissue samples (histologically confirmed diagnosis "Prostate cancer." The samples were examined on the apparatus (HoribaScientific) .Configuration : wavelength 785 nm, grating 1200 gr / mm, 100% filter, confocal hole 300 μm. Integration time 50 s. Analysis of spectral data was carried out using Matlab software, Statistica, FreeSpectraBase, Sp ectraldatabase IndexBio-Rad. Results. Raman spectra of tissue fragments of BPH and PCa correspond to a range of 700-1800 cm-1. Samples with PCa have higher peaks compared to BPH samples at 1280 cm-1 (C-NH2, included in adenine, guanine, cytosine), 1323 cm-1 (CH3 / CH2 collagen), 1378 cm-1 (guanine, adenine, dNA), 1560 cm-1 (adenine and guanine). The spectra of the samples with BPH have higher peaks at 752 cm-1 (tyrosine), 1662 cm -1 (bond amides I: C = O proteins, C = C-bond of lipids). Conclusions. In the study of tissue samples with confirmed diagnoses of BPH and PCa, an increase in the intensity of Raman light scattering of dNA in tissues with confirmed PCa was noted, and a reverse decrease in the intensity of Raman scattering of dNA light in tissues with BPH. Raman spectroscopy showed spectral differences in the biochemical composition of tissues with BPH and tissues with PCa. In the future, this method of investigation can be used to develop a diagnostic algorithm for detecting prostate cancer.Цель исследования. оценить диагностические возможности метода Рамановской спектроскопии в выявлении рака предстательной железы. Материалы и методы. Забор материала:13 образцов предстательной железы (гистологически подтвержден диагноз «доброкачественная гиперплазия предстательной железы» (ДГПЖ). 47 образцов тканей предстательной железы (гистологически подтвержден диагноз «рак предстательной железы».Исследование образцов проводилось на аппарате (HoribaScientific). Конфигурация: длина волны 785 нм, решетка 1200 gr/mm,фильтр 100%, конфокальное отверстие 300 μm.Время интегрирования 50 с. Анализ спектральных данных производился с использованием программного обеспечения Matlab, Statistica, FreeSpectraBase, Spectraldatabase IndexBio-Rad. результаты. Спектры комбинационного рассеяния фрагментов тканей ДГПЖ и РПЖ соответствуют промежутку 700-1800 см-1.образцы с РПЖ имеют более высокие пики по сравнению с образцами ДГПЖ при 1280 см-1(С-NH2 ,входящая в состав аденина,гуанина,цитозина),1323 см-1 (CH3/CH2коллагена),1378 см-1(гуанин,аденин,ДНК),1560 см-1(аденин и гуанин).Спектры образцов с ДГПЖ имеют более высокие пики при 752 см-1(тирозин),1662 см-1(связь амидов I:C=O белков,C=C-связь липидов). Выводы. При исследовании образцов тканей с подтвержденными диагнозами ДГПЖ и РПЖ отмечается увеличение интенсивности Рамановского рассеяния света ДНК в тканях с подтвержденным РПЖ,и обратное снижение интенсивности Рамановского рассеяния света ДНК в тканях с ДГПЖ. Рамановская спектроскопия показала спектральные различия в биохимическом составе тканей с ДГПЖ и тканей с РПЖ. В перспективе данный метод исследования может быть использован для разработки диагностического алгоритма выявления рака предстательной железы

Homothetic perfect fluid space-times

A brief summary of results on homotheties in General Relativity is given, including general information about space-times admitting an r-parameter group of homothetic transformations for r>2, as well as some specific results on perfect fluids. Attention is then focussed on inhomogeneous models, in particular on those with a homothetic group $H_4$ (acting multiply transitively) and $H_3$. A classification of all possible Lie algebra structures along with (local) coordinate expressions for the metric and homothetic vectors is then provided (irrespectively of the matter content), and some new perfect fluid solutions are given and briefly discussed.Comment: 27 pages, Latex file, Submitted to Class. Quantum Gra