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

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

Reconstructing charge-carrier dynamics in porous silicon membranes from time-resolved interferometric measurements

We performed interferometric time-resolved simultaneous reflectance and transmittance measurements to investigate the carrier dynamics in pump-probe experiments on thin porous silicon membranes. The experimental data was analysed by using a method built on the Wentzel-Kramers-Brillouin approximation and the Drude model, allowing us to reconstruct the excited carriers’ non-uniform distribution in space and its evolution in time. The analysis revealed that the carrier dynamics in porous silicon, with ~50% porosity and native oxide chemistry, is governed by the Shockley-Read-Hall recombination process with a characteristic time constant of 375 picoseconds, whereas diffusion makes an insignificant contribution as it is suppressed by the high rate of scattering

Higher Education Reform and Development: The Case of Kazakhstan

Kazakhstan is a country of increasing strategic importance. The size of Western Europe, this oil and mineral rich nation is geographically situated to the south of Russia and the west of China. Nevertheless, its government has demonstrated its commitment to building economic and strategic ties with the West. In the realm of education this was exemplified when Kazakhstan became a signatory of the Bologna Process in 2012. Before 2010, Kazakhstan’s system of higher education operated under the tight control of the Ministry of Education and Science. Fully 70% of the college curriculum was set by the Ministry. The Ministry chose the senior leadership of all public institutions (with the exception of the nine National Universities where rectors were chosen by the country’s president.) Universities could not create endowments or reallocate funds strategically to pursue innovations. The State Program for Education Development, 2010-2020, a policy document endorsed by President Nursultan Nazarbayev in 2011 laid the groundwork for sweeping change. This book examines these changes and places them in the wider socio-political context facing this post-Soviet nation since it declared its independence in 1991. Kazakhstan is one of a number of nations that has sought to move from a highly centralized educational system to one that allows for more autonomy and responsiveness at the local level. The case underscores the significant challenges of enacting reforms that require not only new policies and structures but entail the establishment of an entirely new set of assumptions about what practices promote academic quality and, indeed, about the role of education in society. It intended to serve as a companion volume to David Bridges’ volume on school reform in Kazakhstan. Like that volume, it fills a substantial gap in the literature on education reform in Kazakhstan. Kazakhstan’s experience in many respects reflects the hopes and the challenges faced by other post-Soviet nations seeking to move beyond a bureaucratic and centrally controlled system towards one that is more responsive to the needs of society. Individuals interested in learning about the changes occurring in this strategically important nation and those interested in the possibilities and challenges of education reform in transition economies, especially those that have achieved high levels of literacy and secondary school completion, will find it of interest. The book draws on recent systematic and rigorous research with contributions by senior figures at the centre of reform