1,513 research outputs found

    Spatial variability of climate and past atmospheric circulation patterns from central West Antarctic glaciochemistry

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    Atmospheric circulation patterns and the spatial variability of atmospheric chemistry and moisture transport in central West Antarctica are investigated using new 40 year long (1954–1994 A.D.) glaciochemical and accumulation rate records developed from four firn cores from this region. The core sites lie on a 200 km traverse from 82° 22′ S, 119° 17′ W to 81° 22′ S, 107° 17′ W. The glaciochemical records represent the major ionic species present in Antarctic snow: Na+, K+, Mg2+, Ca2+, Cl−, NO3−, and SO42−. High spatial variability appears in comparisons of full record averages and poor intersite linear correlation results. Accumulation rates show 50–100% changes over distances of 50–100 km and sea‐salt concentrations drop by 50% between the middle two sites. One likely contributor to the high variability seen at this spatial scale is variability in synoptic‐ and finer‐scale meteorology. Empirical orthogonal function (EOF) analysis shows that 80% or more of the variance in site chemistry can be attributed to two types of air masses: winter season air (50–70% of site variance) with a strong marine signature (heavy loading of sea‐salt species) and summer season air (21% of the variance), marked by marine biogenic non‐sea‐salt SO4 plus NO3. This pattern of winter and summer regimes appears at other West Antarctic sites suggesting it may apply to the entire region. We show that a general picture of the patterns of variability in West Antarctica can best be drawn by using an analysis technique that fully exploits high resolution, multiparameter, multisite data sets

    Exact broken-symmetry states and Hartree-Fock solutions for quantum dots at high magnetic fields

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    Wigner molecules formed at high magnetic fields in circular and elliptic quantum dots are studied by exact diagonalization (ED) and unrestricted Hartree-Fock (UHF) methods with multicenter basis of displaced lowest Landau level wave functions. The broken symmetry states with semi-classical charge density constructed from superpositions of the ED solutions are compared to the UHF results. UHF overlooks the dependence of the few-electron wave function on the actual relative positions of electrons localized in different charge puddles and partially compensates for this neglect by an exaggerated separation of charge islands which are more strongly localized than in the exact broken-symmetry states.Comment: QD2004 proceedings under press in Physica

    Повышение рационального использования человеческого потенциала

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    Реферат Выпускная квалификационная работа содержит 131 страницу, 20 рисунков, 39 таблиц, 50 использованных источников, 6 приложений. Ключевые слова: персонал, человеческий потенциал, рациональное использование, адаптация, компетенции, ПАО «ТРК», социальная ответственность компании. . Объектом исследования в работе является: рациональное использование человеческого потенциала компании. . Цель работы - рассмотрение методов повышения рационального использования человеческого потенциала современной компании . В процессе исследования проводились: 1) рассмотрение деятельности компании за 2011 – 2015 гг.; оценка действующей в компании системы управления персоналом и человеческого потенциала компании; 3) внесение предложений по совершенствованию действующей системы управления человеческим потенциалом компании (с расчетом экономической эффективности от внесенных предложений). . В результате исследования: внесены предложения по внедрению в кадровую работу системы периодической сверки компетенций и улучшению работы с кадровым резервом; проведен расчет экономии от внедрения предлагаемых мероприятий . Степень внедрения: запланировано применение внесенных по результатам проведенного исследования предложений в деятельность компании в 2016 г. . Область применения: управление персоналом и человеческим потенциалом в ПАО «ТРК». . Экономическая эффективность/ значимость работы: сумма полученной экономии составит 4 165 тыс. руб. в год. . В будущем планируется: применение внесенных по результатам проведенного исследования предложений в деятельность компании.abstract Final qualifying work includes 131 page, 20 figures, 39 tables, 50 sources used, 6 applications. Keywords: personnel, human potential, rational use, adaptation, competence, PJSC "TRK" social responsibility of the company. . The object of research is in: the rational use of human resources. . Purpose - to examine the methods of enhancing the rational use of the human potential of the modern company. The study carried out: 1) review of the activities of the company for 2011 - 2015 .; assessment of the current in the company personnel management and human resources of the company; 3) make proposals to improve the existing control system of the human potential of the company (with the calculation of the cost-effectiveness of the proposals). . As a result of the study: made suggestions for the implementation of the personnel working in the periodic verification of competency of the system and improvement of work with the personnel reserve; calculated the savings from the implementation of the proposed activities. Degree of implementation: planned application made by the results of the research proposals in the company's activity in 2016. Field of application: personnel management and human potential in PJSC "TRK". . Cost-effectiveness / value of the work: the sum of the savings will amount to 4165 thousand rubles.. in year. . In the future: an application made on the results of the research proposals in the company's activities

    Evaluation of an Electrolyte Analyser for Measurement of Concentrations of Ionized Calcium and Magnesium in Cats

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    The goal of this study was to evaluate the Nova CRT 8 electrolyte analyser for determination of concentrations of ionized calcium (Cai) and magnesium (Mgi) in cats, todetermine the effects of sample handling and storage and to establish reference ranges. The precision and analytical accuracy of the Nova CRT 8 analyser were good. The concentrations of Cai and Mgi were significantly lower in aerobically handled serum samples than in those handled anaerobically. The concentrations of Cai and Mgi differed significantly among whole blood, plasma and serum. In anaerobically handled serum, the concentration of Cai was stable for 8 h at 22°C, for 5 days at 4°C and for 1 week at −20°C. The concentration of Mgi was stable for 4 h at 22°C but for less than 24 h at 4°C and for less than 1 week at −20°C. In serum from 36 cats, the reference ranges were 1.20-1.35 mmol/L for Cai and 0.47-0.59 mmol/L for Mgi. The Nova CRT 8 electrolyte analyser is suitable for determination of Cai and Mgi concentrations in cats. Anaerobically handled serum samples are recommended and, stored at room temperature, they yield accurate results when analysed within 4

    High resolution charge-exchange spectroscopic measurements of aluminum impurity ions in a high temperature plasma

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    Charge-exchange recombination spectroscopy, which is generally used to measure low-Z impurities in fusion devices, has been used for measuring Al+11 and Al+13 impurities in the Madison Symmetric Torus reversed field pinch. To obtain the impurity ion temperature, the experimental emission spectrum is fitted with a model which includes fine structure in the atomic transition. Densities of these two ionization states, calculated from charge-exchange emission brightness, are used in combination with a collisional radiative model to estimate the abundance of all other charge states of aluminum in the plasma and the contribution of aluminum to the effective ionic charge of the plasma

    Neutralizing monoclonal antibodies define two different functional sites in human interleukin-4

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    Human interleukin-4 (IL-4) is a small four-helix-bundle protein which is essential for organizing defense reactions against macroparasites, in particular helminths. Human IL-4 also appears to exert a pathophysiological role during various IgE-mediated allergic diseases. Seven different monoclonal antibodies neutralizing the activity of human IL-4 were studied in order to identify functionally important epitopes. A collection of 41 purified IL-4 variants was used to analyse how defined amino acid replacements affect binding affinity for each individual mAb. Specific amino acid positions could be assigned to four different epitopes. mAbs recognizing epitopes on helix A and/or C interfered with IL-4 receptor binding and thus inhibited IL-4 function. However, other mAbs also inhibiting IL-4 function recognized an epitope on helix D of IL-4 and did not inhibit IL-4 binding to the receptor protein. One mAb, recognizing N-terminal and C-terminal residues, partially competed for binding to the receptor. The results of these mAb epitope analyses confirm and extend previous data on the functional consequences of the amino acid replacements which showed that amino acid residues in helices A and C of IL-4 provide a binding site for the cloned IL-4 receptor and that a signalling site in helix D interacts with a further receptor protein

    Evaluation of cortisol precursors for the diagnosis of pituitary-dependent hypercortisolism in dogs

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    The serum concentrations of cortisol, 17alpha-hydroxypregnenolone, 17alpha-hydroxyprogesterone, 21-deoxycortisol and 11-deoxycortisol were measured in 19 healthy dogs, 15 dogs with pituitary-dependent hypercortisolism (pdh) and eight dogs with other diseases before and one hour after an injection of synthetic adrenocorticotrophic hormone (acth). At both times the dogs with pdh had significantly higher concentrations of cortisol, 17alpha-hydroxypregnenolone, 17alpha-hydroxyprogesterone and 21-deoxycortisol than the healthy dogs. Basal 11-deoxycortisol concentrations were also significantly higher in dogs with pdh compared with healthy dogs. When compared with the dogs with other diseases, the dogs with pdh had significantly higher basal and post-acth cortisol and basal 21-deoxycortisol, and significantly lower post-acth 11-deoxycortisol concentrations. The dogs with other diseases had significantly higher post-acth cortisol, 17alpha-hydroxyprogesterone and 11-deoxycortisol concentrations than the healthy dogs. In general, the post-acth concentrations of 17alpha-hydroxypregnenolone, 17alpha-hydroxyprogesterone, 11-deoxycortisol and 21-deoxycortisol were more variable than the post-acth concentrations of cortisol, resulting in large overlaps of the concentrations of these hormones between the three groups. A two-graph receiver operating characteristic (ROC) analysis was used to maximise the sensitivity and specificity of each hormone for diagnosing hypercortisolism; it showed that the post-acth concentration of cortisol had the highest sensitivity and specificity. The overlaps between the healthy dogs, the dogs with pdh and the dogs with other diseases suggested that the individual precursor hormones would not be useful as a screening test for hypercortisolism

    Follow-up of Bernese Mountain dogs and other dogs with serologically diagnosed Borrelia burgdorferi infection: what happens to seropositive animals?

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    BACKGROUND: Data on the long-term outcome of B. burgdorferi infections in adult dogs are sparse. The aim of the present study was to investigate whether Bernese Mountain dogs with serological evidence of natural B. burgdorferi infection more often develop signs such as lameness, azotemia or proteinuria during a follow-up period of 2.5 to 3.0 years. Seropositive Bernese Mountain dogs were compared to seronegative Bernese Mountain dogs and to seropositive and seronegative control dogs of other breeds. Dogs included in a previous study on the prevalence of antibodies against B. burgdorferi in Bernese Mountain dogs were re-evaluated. Antibodies against B. burgdorferi were determined using an ELISA with a whole-cell sonicate as antigen and results were confirmed using a Western blot assay. RESULTS: Fifty-three Bernese Mountain dogs and 30 control dogs were re-evaluated. Re-evaluation was performed between 2.5 and 3.0 years (median 2.7 years) after the first assessment.The age of the dogs at the second evaluation ranged from 3 to 11 years (median 6 years). There were no significant differences with regard to poor general condition or lameness between the first and the second evaluation. At the first evaluation 22 (42%) of the Bernese Mountain dogs and 11 (37%) of the control dogs were considered positive for antibodies against B. burgdorferi. At the second evaluation 25 (47%) of the Bernese Mountain dogs and 12 (40%) of the control dogs were considered positive; 69% of the dogs showed the same serological result at both examinations and 31% were seroconverted or seroreverted. During the first examination, azotemia was diagnosed in 6 Bernese Mountain dogs and during the second examination in 11 Bernese Mountain dogs. No control dogs had azotemia in this study. In seropositive dogs there was no increase in lameness or signs of renal disease over time. CONCLUSION: It may be concluded that antibodies against B. burgdorferi determined by whole cell ELISA and confirmed by Western blot were neither associated with the development of lameness nor with signs of renal disease like azotemia or proteinuria in dogs observed over a period of 2.5 to 3.0 years

    Eco-Evolutionary Interaction in Competing Phytoplankton: Nutrient Driven Genotype Sorting Likely Explains Dominance Shift and Species Responses to CO2

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    How ecological and evolutionary processes interact and together determine species and community responses to climate change is poorly understood. We studied long-term dynamics (over approximately 200 asexual generations) in two phytoplankton species, a coccolithophore (Emiliania huxleyi), and a diatom (Chaetoceros affinis), to increased CO2 growing alone, or competing with one another in co-occurrence. To allow for rapid evolutionary responses, the experiment started with a standing genetic variation of nine genotypes in each of the species. Under co-occurrence of both species, we observed a dominance shift from C. affinis to E. huxleyi after about 120 generations in both CO2 treatments, but more pronounced under high CO2. Associated with this shift, we only found weak adaptation to high CO2 in the diatom and none in the coccolithophore in terms of species’ growth rates. In addition, no adaptation to interspecific competition could be observed by comparing the single to the two-species treatments in reciprocal assays, regardless of the CO2 treatment. Nevertheless, highly reproducible genotype sorting left only one genotype remaining for each of the species among all treatments. This strong evolutionary selection coincided with the dominance shift from C. affinis to E. huxleyi. Since all other conditions were kept constant over time, the most parsimonious explanation for the dominance shift is that the strong evolutionary selection was driven by the experimental nutrient conditions, and in turn potentially altered competitive ability of the two species. Thus, observed changes in the simplest possible two-species phytoplankton “community” demonstrated that eco-evolutionary interactions can be critical for predicting community responses to climate change in rapidly dividing organisms such as phytoplankton

    Two ground-state modifications of quantum-dot beryllium

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    Exact electronic properties of a system of four Coulomb-interacting two-dimensional electrons in a parabolic confinement are reported. We show that degenerate ground states of this system are characterized by qualitatively different internal electron-electron correlations, and that the formation of Wigner molecule in the strong-interaction regime is going on in essentially different ways in these ground states.Comment: 5 pages, incl 5 Figures and 2 Table
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