253 research outputs found
Assessment of of phosphorus fertilizer wastes production impact on subterranean water quality (Gomel chemical plant, Republic of Belarus)
Relevance. Phosphate raw materials processing at the Gomel chemical plant over a period of more than 50 years has led to accumulation of millions of tons of phosphogypsum dumps. They are a source of subterranean water contamination by sulfates, phosphates and other chemical compounds. Therefore, there is the need in current estimation of the scale and extent of aquifers contamination, taking into account the geological and hydrogeological conditions that influence the migration of contaminants. Aim. Assessment of hydrogeological parameters affecting distribution of contaminants in subterranean water and the degree of aquifers contamination. Objects. Aquifers and impermeable horizons. Methods. Methods for assessment of hydrogeological parameters, methods for determining the chemical composition of subterranean water. Results. The paper assesses a technogenic effect, produced by dumps of Gomel chemical plant. It reviews a subterranean water monitoring local network within the Gomel chemical plant influence area. The hydrogeological parameters of aquifers of the upper hydrodynamic zone are quantitatively assessed, given that this zone undergoes the strongest anthropogenic impact. The study of subterranean water quality ends up with three classes of contamination: high, moderate and insignificant. Sulphates, nitrogen ammonium, phosphorus phosphate are identified as major contaminants. The authors find a spatial pattern of subterranean water contaminants differentiation that tends to develop both horizontally and vertically. As a result of the study, areas and sources of high groundwater contamination are determined and mapped. A conclusion is drawn on the necessity of further control over the subterranean water conditions and contamination development in time and space
Existence and large time behavior for generalized Kelvin-Voigt equations governing nonhomogeneous and incompressible fluids
Generalized Kelvin-Voigt equations governing nonhomogeneous and incompressible
fluids are considered in this work. We assume that, in the momentum equation, the diffusion
and relaxation terms are described by two distinct power-laws. Moreover, we assume that the
momentum equation is perturbed by an extra term, which, depending on whether its signal is
positive or negative, may account for the presence of a source or a sink within the system. For
the associated initial-boundary value problem, we study the existence of weak solutions as well
as the large time behavior of the solutions.Portuguese Foundation for Science and Technology: UID/MAT/04561/2019info:eu-repo/semantics/publishedVersio
ОБЩЕЕ И ОСОБЕННОЕ ВДОПОЛНИТЕЛЬНОМПРОФЕССИОНАЛЬНОМ ОБРАЗОВАНИИ: ПЕРСПЕКТИВЫ РАЗВИТИЯ
The article outlines that further training becomes topical and urgent in the modern times. The authors see the leading role in development of further training as the vector of higher institutions. The paper explores the experience of the system of further training in Krasnoyarsk State Agrarian University; general problems appeared in it and the ways of solution in the agricultural universities. The authors analyze the general aim and tasks of the departments of further training, the current situation, personnel, facilities and additional activity of the department. The paper investigates the external factors influencing further training development and defines the main directions and outlooks of development of further training for the next 5 years.В современную эпоху становится все более актуальным дополнительное профессиональное образование (ДПО). В его развитии ведущая роль в принципе должна принадлежать университетам. В статье на примере деятельности системы ДПО Красноярского государственного аграрного университета рассматриваются общие проблемы, характерные для данных систем университетов страны, а также особенности их проявления и разрешения в конкретном вузе. Анализируются основная цель и задачи структурных подразделений ДПО университета, состояние системы, кадровый потенциал, материально-техническая база, вспомогательная деятельность подразделения. Изучены факторы влияния внешних условий на развитие системы ДПО. Определены основные направления и перспективы развития системы ДПО университета на предстоящее пятилетие
Constraining the optical emission from the double pulsar system J0737-3039
We present the first optical observations of the unique system J0737-3039
(composed of two pulsars, hereafter PSR-A and PSR-B). Ultra-deep optical
observations, performed with the High Resolution Camera of the Advanced Camera
for Surveys on board the Hubble Space Telescope could not detect any optical
emission from the system down to m_F435W=27.0 and m_F606W=28.3. The estimated
optical flux limits are used to constrain the three-component (two thermal and
one non-thermal) model recently proposed to reproduce the XMM-Newton X-ray
spectrum. They suggest the presence of a break at low energies in the
non-thermal power law component of PSR-A and are compatible with the expected
black-body emission from the PSR-B surface. The corresponding efficiency of the
optical emission from PSR-A's magnetosphere would be comparable to that of
other Myr-old pulsars, thus suggesting that this parameter may not dramatically
evolve over a time-scale of a few Myr.Comment: 16 pages, 3 figures, ApJ accepte
Towards a resource-based habitat approach for spatial modelling of vector-borne disease risks
Given the veterinary and public health impact of vector-borne diseases, there is a clear need to assess the suitability of landscapes for the emergence and spread of these diseases. Current approaches for predicting disease risks neglect key features of the landscape as components of the functional habitat of vectors or hosts, and hence of the pathogen. Empirical–statistical methods do not explicitly incorporate biological mechanisms, whereas current mechanistic models are rarely spatially explicit; both methods ignore the way animals use the landscape (i.e. movement ecology). We argue that applying a functional concept for habitat, i.e. the resource-based habitat concept (RBHC), can solve these issues. The RBHC offers a framework to identify systematically the different ecological resources that are necessary for the completion of the transmission cycle and to relate these resources to (combinations of) landscape features and other environmental factors. The potential of the RBHC as a framework for identifying suitable habitats for vector-borne pathogens is explored and illustrated with the case of bluetongue virus, a midge-transmitted virus affecting ruminants. The concept facilitates the study of functional habitats of the interacting species (vectors as well as hosts) and provides new insight into spatial and temporal variation in transmission opportunities and exposure that ultimately determine disease risks. It may help to identify knowledge gaps and control options arising from changes in the spatial configuration of key resources across the landscape. The RBHC framework may act as a bridge between existing mechanistic and statistical modelling approaches
Genotypic distinctions of variability of biochemical composition of fruits of Vacciniaceae species under conditions of Belarus
Result of research of quantitative characteristics of biochemical composition of fruits of 30 taxons of 3 Vacciniaceae species (such as V. corymbosum L. (highbush blueberry), V. vitis-idaea L. (lingonberry) and Oxycoccus macrocarpus (Ait.) Pers. (cranberry)) inter-specific distinctions of a degree of stability of its separate components to complex influence of meteorological factors are revealed by 32 parameters (traits) describing the contents in fruits of some organic acids, carbohydrates, phenolic compounds, terpenoids and major mineral elements are presented. The cultivars possessing by the greatest and accordingly by the least levels of dependence on abiotic factors are identified
The Massive Star Content of NGC 3603
We investigate the massive star content of NGC 3603, the closest known giant
H II region. We have obtained spectra of 26 stars in the central cluster using
the Baade 6.5-m telescope (Magellan I). Of these 26 stars, 16 had no previous
spectroscopy. We also obtained photometry of all of the stars with previous or
new spectroscopy, primarily using archival HST ACS/HRC images. We use these
data to derive an improved distance to the cluster, and to construct an H-R
diagram for discussing the masses and ages of the massive star content of this
cluster.Comment: Accepted by the Astronomical Journal. This revision updates the
coordinates in Table 1 by (-0.18sec, +0.2") to place them on the UCAC2 syste
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