Biomass dynamics of the phytoplankton under impact of the nutrient

AbstractThe phytoplankton production is a basis for a life activity of all species in every aquatic ecological system. Remote sounding methods make it possible to estimate chlorophyll concentration on the ocean surface. The data from remote sounding methods and the data of a nutrient concentration enable us to calculate and model the phytoplankton abundance. These calculations provide a possibility for the description of the phytoplankton production processes. We present here some models for the dynamics of the phytoplankton biomass. The qualitative properties of the solutions of these models are investigated. Strategically activities of the cell are defined by its internal state and by the environmental conditions. The state of the cell depends on nutrients. Our mathematical models describe the abundance dynamics for phytoplankton's community and dynamics of the cellular nutrients content. The models are based on the systems of differential equations. These models may be open or closed relative to the matter. The open models describe the chemostat processes. We investigate the property of the solutions of these models. The closed models have a infinite set of the positive solutions. The open models have a finite set of the non-negative solutions. The algorithm for finding the stable equilibrium solutions in open models is constructed. The theorems about the stable equilibrium solutions are proved with help the methods of structural analysis. These models describe the phytoplankton dynamics in the Black Sea

Educational technologies in professional development of the land reclamation personnel in the context of digitalization

The article analyzes the features of educational technologies for professional development of employees of reclamation organizations in the conditions of the educational and methodological center of additional professional education. The following general scientific research methods have been used: theoretical and practical analysis, development and systematization of information and analytical materials on professional training and development of employees of the Land Reclamation Department of the Ministry of Agriculture of the Russian Federation, logical and situational analysis, selective method in statistics, and result processing and generalization method. Relevant educational technologies for professional development of ameliorative industry workers and their gender-specific features, job categories, and stages of professional development that allow to determine significant changes in human resources of the industry have been identified for the first time. The features of implementation of promising areas of workers’ professional development in the reclamation industry of the agribusiness of the Ministry of Agriculture of the Russian Federation in the conditions of digital transformation have been revealed

Scientific Retrospective of the Farm Irrigation Systems Efficient Use

This article presents the results of a scientific-practical research on Russian agribusiness ameliorative department efficiency. There are the results of the analysis and retrospective of domestic and foreign views on the agriculture effectiveness and, in particular, the irrigated agriculture efficiency, Organization for Economic Co-operation and Development (OECD) countries’ experience. The methodological approaches to understanding the economic development effectiveness are clarified and an extended classification of efficiency types is proposed. The author’s approach to the farm irrigation systems efficient use concept is presented. The agricultural economic efficiency structure has been determined. The factors that can contribute to increasing the investment attractiveness and efficiency of irrigated agriculture are identified. Theoretical and methodological approaches to assess the irrigated agriculture effectiveness, considering the problems identified in the process of this study, are proposed

Mechanisms of regulation of invasive processes in phytoplankton on the example of the north-eastern part of the Black Sea

© 2016, Springer Science+Business Media Dordrecht. In the north-eastern part of the Black Sea, the seasonal complexes of dominant species of phytoplankton were fixed: small-celled diatom (spring), coccolithophores (late spring, early summer) and large diatoms (summer and autumn). In May–June 2005 and 2006, two invasive species of marine diatoms Chaetoceros throndsenii (maximal abundance 1.92 × 105 cells/l) and Chaetoceros minimus (1.6 × 105 cells/l) were recorded. These species have been incorporated in the complex of the late spring and early summer and grew simultaneously with the coccolithophore Emiliania huxleyi. The coccolithophore was dominant species, whose abundance had reached the level of a bloom. C. throndsenii was observed over the entire area from the coast to the centre of the sea; C. minimus were recorded at coastal stations and only at two stations of the open sea. Stratification of the water mass and the low (below the Redfield) ratio of nitrogen to phosphorus were observed at this time. Then, C. throndsenii was not marked even once, and C. minimus has been registered once on a shelf in June 2011. Experimental studies (2005) have shown that intensive growth C. throndsenii requires the simultaneous addition of nitrogen and phosphorus in a ratio close to the Redfield ratio. C. minimus shows the intensive growth only at high concentrations of phosphorus and at low nitrogen-to-phosphorus ratio (the experiment was carried out in June 2011). Mathematical modelling shows that C. throndsenii and Emiliania huxleyi form a stable couple whose growth is limited by different factors: the diatoms by nitrogen and the coccolithophores by phosphorus. C. minimus might not be able to form a stable couple with coccolithophores because they have the same limiting factor, i.e. phosphorus. However, this species could become the dominant one, if low (0.5–1) nitrogen-to-phosphorus ratio conditions were stable for more than 2 months. However, this scenario is improbable in natural circumstances since the existence of this complex seasonal rarely exceeds 1.5 months

ТОКСОКАРОЗ У НАСЕЛЕНИЯ ГРУПП РИСКА ПО ВИЧ И ГЕПАТИТАМ В РЕСПУБЛИКЕ АЛТАЙ

From HIV and hepatitis B and C risk groups 314 residents of the Republic of Altai were serologically examined for toxocarosis, HIV and hepatitis risk group includes medical workers, public servants, the unemployed, housewives and pensioners, 5,1 % of which (178 persons) had mixed infection of toxocarosis and hepatitis. 136 persons from the HIV risk group were not ill with toxocarosis.314 жителей Республики Алтай из групп риска по ВИЧ и гепатитам В и С обследованы серологически на токсокароз, ВИЧ и гепатиты. У 5,1 % человек из группы риска по гепатитам (178 человека) зарегистрировано совместное заражение токсокарозом и гепатитом. Из 136 человек группы риска по ВИЧ серопозитивных по токсокарозу не выявлено

Protoplasmic streaming of chloroplasts enables rapid photoacclimation in large diatoms

Long-term (2004–2020) studies showed yearly summer/autumn blooms in the NE Black Sea dominated by large (cell volume > 5000 μm3) diatoms (Pseudosolenia calcar-avis and Proboscia alata). This phenomenon is characterized by high (>250 W m−2 photosynthetically active radiation, PAR) insolation, and low phosphorus concentrations (to analytical zero). These diatoms contained >100 chloroplasts per cell, which at low irradiance are evenly distributed throughout the cell. As light increases (to 1000 μmol photons m−2 s−1 PAR), chloroplasts aggregate within 20 min, usually to the centre of the cell. In consequence, the light absorption coefficient is decreased by >3 fold. At elevated photon flux density (PFD), P. calcar-avis also shows a “conveyor” of chloroplasts moving from the aggregate to the cell periphery and back. This mechanism enables a continuous fine-tuning of the cells’ ability to absorb light, likely also facilitating photo-damage repair. This rapid photoacclimation mechanism allows large diatoms to minimize photodamage at high PFD and acclimate well to low PFD. We hypothesize that competitive success of large diatoms in conditions of high light gradients is aided by this short-term rapid photoacclimation enhancing growth rate while minimizing chloroplast repair costs, aided by the ability of large cells to accumulate nutrients for chloroplast synthesis

ИЗУЧЕНИЕ АНТИПАРАЗИТАРНЫХ СВОЙСТВ ДЕЗАВИДА В УСЛОВИЯХ IN VIVO

The action of disinfectant dezavid on Toxocara canis eggs in vivo is investigated. Dezavid in concentration of 0,1 %, 0,2; 0,4; 0,8; 1,6; 2,4 and 3,2 % has oocid and larvicid actions. With increase of concentration of dezavid solutions the terms of larvae life in eggs T. сanis and the period of destruction of eggs are shortened. Dezavid is recommended for disinfection an environment and excrements of dogs from eggs T. сanis. It is expedient to use of dezavid in higher concentration for reduction of terms desinfection of environment.В лабораторных условиях изучено действие дезинфицирующего средства дезавид на яйца Toxocara canis. Дезавид в концентрации 0,1 %, 0,2; 0,4; 0,8; 1,6; 2,4 и 3,2 % обладает овоцидным и ларвоцидным действиями. С увеличением концентрации растворов дезавида укорачиваются сроки жизни личинок в яйцах Т. сanis и период разрушения яиц. Дезавид рекомендуется для дезинвазии окружающей среды и испражнений собак от яиц Т. сanis. Для сокращения сроков дезинвазии окружающей среды целесообразно использовать дезавид в более высоких концентрациях

ЭПИЗООТИЧЕСКАЯ СИТУАЦИЯ ПО ТОКСОКАРОЗУ И ЕГО ПРОФИЛАКТИКА В ЦЕНТРЕ КИНОЛОГИЧЕСКОЙ СЛУЖБЫ МИНИСТЕРСТВА ВНУТРЕННИХ ДЕЛ РЕСПУБЛИКИ АЛТАЙ

Contamination of dogs with Toxocara canis and efficiency of prevention measures of toxocarosis in cynological center of Altai Republic is studied.Изучена зараженность служебно-розыскных собак Toxocara canis и эффективность проводимых мероприятий по профилактике токсокароза в питомнике Центра кинологической службы МВД Республики Алтай