Artificial boundary conditions for the linearized Benjamin-Bona-Mahony equation

International audienceWe consider various approximations of artificial boundary conditions for linearized Benjamin-Bona-Mahoney equation. Continuous (respectively discrete) artificial boundary conditions involve non local operators in time which in turn requires to compute time convolutions and invert the Laplace transform of an analytic function (respectively the Z-transform of an holomorphic function). In this paper, we derive explicit transparent boundary conditions both continuous and discrete for the linearized BBM equation. The equation is discretized with the Crank Nicolson time discretization scheme and we focus on the difference between the upwind and the centered discretization of the convection term. We use these boundary conditions to compute solutions with compact support in the computational domain and also in the case of an incoming plane wave which is an exact solution of the linearized BBM equation. We prove consistency, stability and convergence of the numerical scheme and provide many numerical experiments to show the efficiency of our tranparent boundary conditions

Impurity breakdown and terahertz luminescence in n-GaN epilayers under external electric field

We report on the observation and experimental studies of impurity breakdown and terahertz luminescence in n-GaN epilayers under external electric field. The terahertz electroluminescence is observed in a wide range of doping levels (at noncompensated donor density from 4.5×10[sup 16] to 3.4×10[sup 18] cm[sup −3]). Spectra of terahertz luminescence and photoconductivity are studied by means of Fourier transform spectrometry. Distinctive features of the spectra can be assigned to intracenter electron transitions between excited and ground states of silicon and oxygen donors and to hot electron transitions to the donor states.Peer reviewe

Исследование сорбции лекарственных веществ перфтораном

Objective: to estimate the perfluorane adsorption capacity of the drugs belonging to different pharmacological groups. Materials and methods. The binding of perfluorane to 50 drugs at concentrations of 12.5 to 100 ^M was studied in vitro using equilibrium dialysis. Results. Interactions of ligands with the particles of perfluorane emulsion were found to be of three types. Type 1 substances were characterized by negative affinity to perfluorane; type 2 ligands acted indifferently with the emulsion; type 3 compounds were reversibly adsorbed with the particles of the blood substitute by the affinity constants ( Kaff) of 104 M-1. Conclusion. The perfluorane adsorption capacity is ambiguous and seems to depend on the properties of ligands. Type 3 interactions, which may lead to an increase in blood adsorption capacity and change in the pharmacokinet-ics of drugs used in combination with perfluorane, appear to be the most important. Key words: perfluorane, binding, drugs, drug interactions.Цель исследования — оценка сорбционной способности перфторана в отношении лекарственных веществ, принадлежащих к различным фармакологическим группам. Материалы и методы. В экспериментах in vitro с помощью метода равновесного диализа исследована степень связывания с перфтораном 50 лекарственных веществ, взятых в концентрациях от 12,5 до 100 мкМ. Результаты. Выявлены три типа взаимодействия лигандов с частицами эмульсии перфторана. Вещества первого типа характеризовались негативной тропностью к перфторану; ли-ганды второго типа вели себя индифферентно по отношению к эмульсии; соединения третьего типа обратимо сорбировались частицами кровезаменителя с константами взаимодействия Kag порядка 104 М-1. Заключение. Сорбционная активность перфторана в отношении лекарственных веществ проявляется неоднозначно и, по-видимому, зависит от свойств лигандов. Наиболее значимыми представляются взаимодействия третьего типа, результатом которых может стать увеличение сорбционной емкости крови и изменение фармакокинетики лекарств, используемых совместно с перфтораном. Ключевые слова: перфторан, связывание, лекарственные вещества, лекарственные взаимодействия

Community evaluation of glycoproteomics informatics solutions reveals high-performance search strategies for serum glycopeptide analysis

Glycoproteomics is a powerful yet analytically challenging research tool. Software packages aiding the interpretation of complex glycopeptide tandem mass spectra have appeared, but their relative performance remains untested. Conducted through the HUPO Human Glycoproteomics Initiative, this community study, comprising both developers and users of glycoproteomics software, evaluates solutions for system-wide glycopeptide analysis. The same mass spectrometrybased glycoproteomics datasets from human serum were shared with participants and the relative team performance for N- and O-glycopeptide data analysis was comprehensively established by orthogonal performance tests. Although the results were variable, several high-performance glycoproteomics informatics strategies were identified. Deep analysis of the data revealed key performance-associated search parameters and led to recommendations for improved 'high-coverage' and 'high-accuracy' glycoproteomics search solutions. This study concludes that diverse software packages for comprehensive glycopeptide data analysis exist, points to several high-performance search strategies and specifies key variables that will guide future software developments and assist informatics decision-making in glycoproteomics

Deciphering Heterogeneity in Pig Genome Assembly Sscrofa9 by Isochore and Isochore-Like Region Analyses

Background: The isochore, a large DNA sequence with relatively small GC variance, is one of the most important structures in eukaryotic genomes. Although the isochore has been widely studied in humans and other species, little is known about its distribution in pigs. Principal Findings: In this paper, we construct a map of long homogeneous genome regions (LHGRs), i.e., isochores and isochore-like regions, in pigs to provide an intuitive version of GC heterogeneity in each chromosome. The LHGR pattern study not only quantifies heterogeneities, but also reveals some primary characteristics of the chromatin organization, including the followings: (1) the majority of LHGRs belong to GC-poor families and are in long length; (2) a high gene density tends to occur with the appearance of GC-rich LHGRs; and (3) the density of LINE repeats decreases with an increase in the GC content of LHGRs. Furthermore, a portion of LHGRs with particular GC ranges (50%–51 % and 54%–55%) tend to have abnormally high gene densities, suggesting that biased gene conversion (BGC), as well as time- and energy-saving principles, could be of importance to the formation of genome organization. Conclusion: This study significantly improves our knowledge of chromatin organization in the pig genome. Correlations between the different biological features (e.g., gene density and repeat density) and GC content of LHGRs provide a uniqu

Physical activity of pregnant women as an object of a favorable course of pregnancy

The paper analyzed the effect of physical activity on the course of pregnancy. This study was conducted using the methods of questioning and analysis of medical records of pregnant women. The data we obtained confirm the importance of the fact that regular physical activity before and during pregnancy reduces the risk of developing gestational diabetes mellitus, gestational arterial hypertension and prevents the impairment of uteroplacental blood flow.В работе был проведен анализ влияния физической активности на течение беременности. Данное исследование было проведено с помощью методов анкетирования и анализа обменных карт беременных. Полученные нами данные подтверждают важность того факта, что регулярная физическая активность до и во время беременности снижает риск развития гестационного сахарного диабета, гестационной артериальной гипертензии и предотвращают нарушение маточно - плацентарного кровотока

Zonal Peculiarities of Forest Vegetation Controlled by Fires in Northern Siberia

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