212 research outputs found
Информационные технологии как неотьемлемая составляющая нового образовательного процесса
У статті розглядаються проблеми, пов’язані із переходом до інформаційного суспільства; ми прагнемо окреслити шляхи перебудови та адаптації традиційної системи освіти до нових умов сучасності. Були виокремленні та проаналізовані найефективніші інформаційні технології в системі освіти, увага акцентується на потребі формування інформаційної культури всіх суб’єктів
освітнього процесу.Іn the article problems are examined related to transition to informative society, we aim to outline the ways of alteration and adaptation of the traditional system of education to the new terms of contemporaneity. Were selected and analys the most effective informations technologies in the system of education, attention is accented on the necessity of forming of informative culture of all subjects of educational process.В статье рассматриваются проблемы, связанные с переходом к информационному обществу; мы стремимся очертить пути перестройки и адаптации традиционной системы образования к новым условиям современности. Были выделены и проанализированы самые эффективные информационные технологии в системе образования, внимание акцентируется на потребности формирования информационной культуры всех субъектов образовательного процесса
Inelastic scattering of broadband electron wave packets driven by an intense mid-infrared laser field
Intense, 100 fs laser pulses at 3.2 and 3.6 um are used to generate, by
multi-photon ionization, broadband wave packets with up to 400 eV of kinetic
energy and charge states up to Xe+6. The multiple ionization pathways are well
described by a white electron wave packet and field-free inelastic cross
sections, averaged over the intensity-dependent energy distribution for (e,ne)
electron impact ionization. The analysis also suggests a contribution from a 4d
core excitation in xenon
Algebraic structure of gravity in Ashtekar variables
The BRST transformations for gravity in Ashtekar variables are obtained by
using the Maurer-Cartan horizontality conditions. The BRST cohomology in
Ashtekar variables is calculated with the help of an operator
introduced by S.P. Sorella, which allows to decompose the exterior derivative
as a BRST commutator. This BRST cohomology leads to the differential invariants
for four-dimensional manifolds.Comment: 19 pages, report REF. TUW 94-1
Toxoplasma gondii in beef consumed in France: Regional variation in seroprevalence and parasite isolation
In France, the consumption of cattle and sheep meat appears to be a risk factor for infection of pregnant women with Toxoplasma gondii. Several nation-wide surveys in France have investigated the prevalence of T. gondii in sheep and pig meat, but little is known at present about the prevalence of the parasite in beef. The main objective of the present cross-sectional survey was to estimate the seroprevalence of T. gondii infection in beef consumed in France. A secondary objective was to attempt to isolate T. gondii from cattle tissues and to study the geographical and age variations of this seroprevalence. The overall estimate of seroprevalence of T. gondii in bovine carcasses (n = 2912), for a threshold of 1:6 was 17.38%. A strong age effect was observed (p lt 0.0001) with a seroprevalence of 5.34% for calves ( lt 8 months) and 23.12% for adults ( gt 8 months). Seroprevalence estimates given by area of birth and area of slaughtering for adults showed that the areas with the highest seroprevalence were not the same between these two variables. Only two strains, corresponding to genotype II, were isolated from heart samples, indicating that there is a limited risk of human infection with T. gondii, which needs to be correlated with the food habit of consuming raw or undercook (bleu or saignant) beef. However, new questions have emerged, especially concerning the isolation of parasites from beef and the precise role of bovines, generally described as poor hosts for T. gondii, in human infection
Eco-friendly Production of Chemicals 1. Improvement of Enzymatic Production of Acetophenone by Direct Extraction
Acetophenone can be enzymatically produced by conversion of methylbenzylamine using transaminase. The enzymatic process
is strongly affected by the product inhibition, thus requiring the acetophenone removal from the media during its synthesis. In
this purpose, the individual and selective extraction of acetophenone and methylbenzylamine with the biocompatible solvent nheptane containing 1-octanol, D2EHPA or TOA has been analyzed at three values of pH (5, 7, and 9). Regardless of the solvent
used and pH-value, the highest efficiency has been reached for extraction of acetophenone, the difference between the extraction
yields of acetophenone and methylbenzylamine being amplified during the separation of these compounds from their mixture. On
the basis of the experimental selectivity factors and taking into consideration both the possible loss of substrate from the media
and the pH required for enzymatic reaction, pH = 7, it has been concluded that the optimum solvent combination is the mixture
between n-heptane and 1-octanol. This solvent mixture allowed reaching high selectivity factor of 315, corresponding to the
extraction yield of acetophenone of 94.5 % and of methylbenzylamine of only 0.3 %
Nonlinear stability analysis of the Emden-Fowler equation
In this paper we qualitatively study radial solutions of the semilinear
elliptic equation with and on the
positive real line, called the Emden-Fowler or Lane-Emden equation. This
equation is of great importance in Newtonian astrophysics and the constant
is called the polytropic index. By introducing a set of new variables, the
Emden-Fowler equation can be written as an autonomous system of two ordinary
differential equations which can be analyzed using linear and nonlinear
stability analysis. We perform the study of stability by using linear stability
analysis, the Jacobi stability analysis (Kosambi-Cartan-Chern theory) and the
Lyapunov function method. Depending on the values of these different
methods yield different results. We identify a parameter range for where
all three methods imply stability.Comment: 12 pages; new reference added; 3 new references added; fully revised
versio
Ultraintense X-Ray Induced Ionization, Dissociation, and Frustrated Absorption in Molecular Nitrogen
Sequential multiple photoionization of the prototypical molecule N_2 is studied with femtosecond time resolution using the Linac Coherent Light Source (LCLS). A detailed picture of intense x-ray induced ionization and dissociation dynamics is revealed, including a molecular mechanism of frustrated absorption that suppresses the formation of high charge states at short pulse durations. The inverse scaling of the average target charge state with x-ray peak brightness has possible implications for single-pulse imaging applications
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