Influence of incoherent scattering on stochastic deflection of high-energy negative particle beams in bent crystals

An investigation on stochastic deflection of high-energy negatively charged particles in a bent crystal was carried out. On the basis of analytical calculation and numerical simulation it was shown that it exists a maximum angle at which most of the beam is deflected. The existence of a maximum, which is taken in the correspondence of the optimal radius of curvature, is a novelty with respect to the case of positively charged particles, for which the deflection angle can be freely increased by increasing the crystal length. This difference has to be ascribed to the stronger contribution of incoherent scattering affecting the dynamics of negative particles that move closer to atomic nuclei and electrons. We therefore identified the ideal parameters for the exploitation of axial confinement for negatively charged particle beam manipulation in future high-energy accelerators, e.g., ILC or muon colliders

Stochastic mechanism of a high-energy charged-particle beam deflection by a bent crystal

The efficiency dependence on particles energy for the stochastic mechanism of a high-energy charged-particle beam deflection by a bent crystal was analysed. It was shown that with particles energy decrease the maximal possible angle of beam deflection increases. The influence of incoherent effects on particles scattering was also analysed

Zooplankton carcasses and non-predatory mortality in freshwater and inland sea environments

Zooplankton carcasses are ubiquitous in marine and freshwater systems, implicating the importance of non-predatory mortality, but both are often overlooked in ecological studies compared with predatory mortality. The development of several microscopic methods allows the distinction between live and dead zooplankton in field samples, and the reported percentages of dead zooplankton average 11.6 (minimum) to 59.8 (maximum) in marine environments, and 7.4 (minimum) to 47.6 (maximum) in fresh and inland waters. Common causes of non-predatory mortality among zooplankton include senescence, temperature change, physical and chemical stresses, parasitism and food-related factors. Carcasses resulting from non-predatory mortality may undergo decomposition leading to an increase in microbial production and a shift in microbial composition in the water column. Alternatively, sinking carcasses may contribute significantly to vertical carbon flux especially outside the phytoplankton growth seasons, and become a food source for the benthos. Global climate change is already altering freshwater ecosystems on multiple levels, and likely will have significant positive or negative effects on zooplankton non-predatory mortality. Better spatial and temporal studies of zooplankton carcasses and non-predatory mortality rates will improve our understanding of this important but under-appreciated topic

Names of Vladimir the Great in Liturgical Texts and the Perception of his Sainthood in the 14th and 17th Centuries

The article examines attributive and agentive names of the grand prince of Kiev, Vladimir Svyatoslavich as they appear in liturgical texts of the 14th and 17th centuries, that either circulated independently or were employed at church services especially dedicated to the saint. Presuming that the first laudatory songs glorifying Vladimir date back to the 12th century, the author observes the steady increase of the number of such attributive and agentive names in liturgical texts and marks the period from the 14th through the 17th centuries as a peak of textual activity surrounding Vladimir. As the tables included in the article indicate, the increase in number was accompanied by the corresponding increase in semantic and imagery complexity. The names, employed in broader contextual meanings, became associated with various semantic fields and, above all, began to express abstract ideas related to the ideal vision of the personality of the saint and its historical, metaphysical, and spiritual dimensions

On the dependence of the efficiency of stochastic mechanism of charged particle beam deflection in a bent crystal on the particle energy

The problem of stochastic deflection of high-energy charged particles was considered on the basis of analytical calculation and numerical simulation. It was shown that with increasing energy of charged particles the maximal deflection angle, achievable with a help of stochastic deflection mechanism decreases as E^(-1/4), while the optimal radius of crystal curvature, which corresponds to this maximal deflection angle, increases as E^(5/4).За допомогою аналітичних розрахунків і числового моделювання була розглянута задача про стохастичне відхилення високоенергетичних заряджених частинок зігнутим кристалом. Було показано, що з ростом енергії заряджених частинок максимальний кут відхилення, який є досяжним при використанні стохастичного механізму відхилення, зменшується як E^(-1/4), в той час як оптимальний радіус викривлення кристала, що відповідає цьому максимальному куту відхилення, зростає як E^(5/4).При помощи аналитических расчётов и численного моделирования была рассмотрена задача о стохастическом отклонении высокоэнергетических заряженных частиц изогнутым кристаллом. Было показано, что с ростом энергии заряженных частиц максимальный угол отклонения, достижимый при использовании стохастического механизма отклонения, уменьшается как E^(-1/4), в то время как оптимальный радиус кривизны кристалла, соответствующий этому максимальному углу отклонения, растёт как E^(5/4)

Climate Change Demands Adaptive Management of Urban Lakes: Model-Based Assessment of Management Scenarios for Lake Tegel (Berlin, Germany)

Lakes are known to be strongly affected by climate change as a result of their sensitivity to atmospheric forcing. The combined response of urban lakes to climatic changes and to urbanization of the catchment may be further altered by water quality management measures. We studied Lake Tegel in Berlin, Germany as a representative urban lake profoundly influenced by intense water management measures and a resulting complex hydrodynamic situation: Lake Tegel is fed by nutrient-rich river discharges and effluents from a phosphorus elimination plant (PEP). We estimated changes in water temperatures, the Wedderburn number, and the buoyancy frequency, as well as concentrations of dissolved oxygen and phosphate under climate change using a one-dimensional vertical hydrodynamic model coupled to a water quality model. Further, we investigated how four management scenarios with varying discharges of the PEP could affect the lake system. In all simulations, water temperatures increased and summer stratification extended. The modeling results demonstrated that the water management system buffers the high nutrient supply from the river inflow and can effectively mitigate negative effects of climate change on Lake Tegel, thus highlighting its importance for the lake ecosystem.DFG, 248198858, GRK 2032: Grenzzonen in urbanen Wassersysteme

Hydrofoil flow over the interface of a two-layer heavy fluid with a free surface and rigid bottom

The theory of small-amplitude waves is used to analyze the hydrofoil flow of a two-layer heavy fluid. The upper layer is bounded by a free surface, while the lower layer is bounded by a horizontal bottom. simulation of boundaries by singularities. Due to this method, the boundary condition specified on the contour is satisfied analytically exactly. By using the interface conditions, the problem is reduced to two systems of three singular integrodifferential equations. A special regularization technique gives systems of linear integral equations, which are solved numerically by applying the method of successive approximations with the use of a specially developed algorithm and a FORTRAN program. The numerical-analytical method developed applies to a wing section of arbitrary, including actual, shape placed in a fluid flow with interfaces of various types. The computations were performed for a NACA 66mod hydrofoil. The influence exerted by the angle of attack and the interfaces on the hydrodynamic hydrofoil characteristics is investigated in different ranges of Froude numbers. Shapes of internal and surface waves are obtained. Hydrodynamic effects associated with the dead water phenomenon are detected. © 2010 Pleiades Publishing, Ltd

Online object oriented Monte Carlo computational tool for the needs of biomedical optics

Conceptual engineering design and optimization of laser-based imaging techniques and optical diagnostic systems used in the field of biomedical optics requires a clear understanding of the light-tissue interaction and peculiarities of localization of the detected optical radiation within the medium. The description of photon migration within the turbid tissue-like media is based on the concept of radiative transfer that forms a basis of Monte Carlo (MC) modeling. An opportunity of direct simulation of influence of structural variations of biological tissues on the probing light makes MC a primary tool for biomedical optics and optical engineering. Due to the diversity of optical modalities utilizing different properties of light and mechanisms of light-tissue interactions a new MC code is typically required to be developed for the particular diagnostic application. In current paper introducing an object oriented concept of MC modeling and utilizing modern web applications we present the generalized online computational tool suitable for the major applications in biophotonics. The computation is supported by NVIDEA CUDA Graphics Processing Unit providing acceleration of modeling up to 340 times

Effects of the Largest Lake of the Tibetan Plateau on the Regional Climate

Qinghai Lake is the largest lake in China. However, its influence on the local climate remains poorly understood. By using an atmosphere-lake coupled model, we investigated the impact of the lake on the local climate. After the adjustment of four key parameters, the model reasonably reproduced the lake-air interaction. Superimposed by the orographic effects on lake-land breeze circulation, the presence of the lake enhanced precipitation over the southern part of the lake and its adjacent land, while slightly reduced precipitation along the northern shore of the lake. The lake effect on local precipitation revealed a distinct seasonal and diurnal variability, reducing precipitation in May (-6.6%) and June (-4.5%) and increasing it from July (5.7%) to November (125.6%). During the open water season, the lake's daytime cooling effect weakened and the nighttime warming effect strengthened, affecting spatial distribution and intensity of lake-induced precipitation. In early summer, precipitation slightly decreased over the north part of the lake due to the lake's daytime cooling. In turn, lake-induced nighttime warming increased precipitation over the southern section of the lake and its adjacent land. With the start of the autumn cooling in September, heat and moisture fluxes from the lake resulted in precipitation increase in both daytime and nighttime over the entire lake. In October, the background atmospheric circulation coupled with the strong lake effects lead to a small amount but high proportion of lake-induced precipitation spreading evenly over the lake.Peer reviewe