100 research outputs found

    Studies of contribution of metals bonded with organic matter of seawater to the fluxes of total dissolved metals across water-sediment interface at Vistula Lagoon of Baltic Sea

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    © 2004 IEEE. Investigations of fluxes of a dissolved element across the water-sediment interface in Vistula Lagoon (Baltic Sea) were carried out in August 2001 and 2002, using chamber experiments. Oxygen, iron(II), total dissolved iron, manganese, copper and lead fluxes were calculated. For the first time the fluxes of metals bonded with organic matter of sea water were studied. The contribution of metals bonded with organic matter to the total flux was varied depending upon conditions and may reach up to 70 %. It was found that metal fluxes at the coastal zone are larger than at the center of the lagoon by the factor of 2-4

    Studies of fluxes of dissolved iron and manganese in the Gulf of Finland

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    © 2004 IEEE. Metal fluxes (total dissolved iron and manganese) across the water-sediment interface were studied in situ in the Gulf of Finland in June 2002 and 2003 using an autonomous benthic lander. Distribution of these metals in the sediment and the porewater was also investigated. Focus was given to understand the behavior of the studied metals at various redox conditions and the influence when sediment resuspension is occurring. Our data indicate the importance of the redox conditions for the iron fluxes with no fluxes at oxic, intermediate at anoxic and high fluxes at suboxic conditions. The fluxes of manganese do not seem to have any correlation with the oxygen levels. Both metals were significantly affected by resuspension, which led to a rapid release

    Microtubules gate tau condensation to spatially regulate microtubule functions.

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    Tau is an abundant microtubule-associated protein in neurons. Tau aggregation into insoluble fibrils is a hallmark of Alzheimer's disease and other types of dementia1, yet the physiological state of tau molecules within cells remains unclear. Using single-molecule imaging, we directly observe that the microtubule lattice regulates reversible tau self-association, leading to localized, dynamic condensation of tau molecules on the microtubule surface. Tau condensates form selectively permissible barriers, spatially regulating the activity of microtubule-severing enzymes and the movement of molecular motors through their boundaries. We propose that reversible self-association of tau molecules, gated by the microtubule lattice, is an important mechanism of the biological functions of tau, and that oligomerization of tau is a common property shared between the physiological and disease-associated forms of the molecule

    Комплекс машин для производства лука по ресурсосберегающим технологиям

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    Relevance. The most common and most mastered method of growing onions, used in the middle zone of the Russian Federation, as well as in the northern part of European countries, is the cultivation of turnip onions from onion. It is believed that this method provides 75% of the production of the entire onion harvest. Due to the sharp increase in the prices of energy carriers, fertilizers, pesticides and agricultural machinery, the production of sharp varieties of onions, grown in the crop, has become unprofitable, and marketable products have lost competitiveness due to high costs. Significant changes in the reduction of labor costs can be achieved by improving the technology and technical means for the production of onions, creating conditions for their work. The effectiveness of designs for sowing seeds of onions, onion sets and planting onions-uterus is determined by the uniform distribution of the bulbs by area of nutrition, depth and their embedding.Results. The material presented in the work is devoted to the analysis of designs and some results of studies of a complex of machines for the production of onions developed in the Penza GAU. Актуальность. Самым распространенным и наиболее освоенным способом выращивания лука, применяемым в средней полосе Российской Федерации, а также в северной части европейских стран, является выращивание лука-репки из севка. Считается, что этот способ обеспечивает 75% продукции всего урожая лука. Из-за резкого повышения цен на энергоносители, удобрения, пестициды и сельхозмашины производство репчатого лука острых сортов, выращиваемого в севочной культуре, стало нерентабельным, а товарная продукция потеряла конкурентоспособность из-за высокой себестоимости. Существенных изменений в сокращении затрат труда можно достичь путем совершенствования технологии и технических средств для производства лука, создания условий для их работы. Эффективность конструкций для посева семян лука, лука-севка и посадки лука-матки определяются равномерностью распределения луковиц по площади питания, глубине и их заделки.Результаты. Представленный в работе материал, в основном, посвящен анализу конструкций и некоторых результатов исследований комплекса машин, для производства лука, разработанных в Пензенском ГАУ.

    Scanning tunneling spectroscopy of high-temperature superconductors

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    Tunneling spectroscopy played a central role in the experimental verification of the microscopic theory of superconductivity in the classical superconductors. Initial attempts to apply the same approach to high-temperature superconductors were hampered by various problems related to the complexity of these materials. The use of scanning tunneling microscopy/spectroscopy (STM/STS) on these compounds allowed to overcome the main difficulties. This success motivated a rapidly growing scientific community to apply this technique to high-temperature superconductors. This paper reviews the experimental highlights obtained over the last decade. We first recall the crucial efforts to gain control over the technique and to obtain reproducible results. We then discuss how the STM/STS technique has contributed to the study of some of the most unusual and remarkable properties of high-temperature superconductors: the unusual large gap values and the absence of scaling with the critical temperature; the pseudogap and its relation to superconductivity; the unprecedented small size of the vortex cores and its influence on vortex matter; the unexpected electronic properties of the vortex cores; the combination of atomic resolution and spectroscopy leading to the observation of periodic local density of states modulations in the superconducting and pseudogap states, and in the vortex cores.Comment: To appear in RMP; 65 pages, 62 figure

    How Molecular Motors Are Arranged on a Cargo Is Important for Vesicular Transport

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    The spatial organization of the cell depends upon intracellular trafficking of cargos hauled along microtubules and actin filaments by the molecular motor proteins kinesin, dynein, and myosin. Although much is known about how single motors function, there is significant evidence that cargos in vivo are carried by multiple motors. While some aspects of multiple motor function have received attention, how the cargo itself —and motor organization on the cargo—affects transport has not been considered. To address this, we have developed a three-dimensional Monte Carlo simulation of motors transporting a spherical cargo, subject to thermal fluctuations that produce both rotational and translational diffusion. We found that these fluctuations could exert a load on the motor(s), significantly decreasing the mean travel distance and velocity of large cargos, especially at large viscosities. In addition, the presence of the cargo could dramatically help the motor to bind productively to the microtubule: the relatively slow translational and rotational diffusion of moderately sized cargos gave the motors ample opportunity to bind to a microtubule before the motor/cargo ensemble diffuses out of range of that microtubule. For rapidly diffusing cargos, the probability of their binding to a microtubule was high if there were nearby microtubules that they could easily reach by translational diffusion. Our simulations found that one reason why motors may be approximately 100 nm long is to improve their ‘on’ rates when attached to comparably sized cargos. Finally, our results suggested that to efficiently regulate the number of active motors, motors should be clustered together rather than spread randomly over the surface of the cargo. While our simulation uses the specific parameters for kinesin, these effects result from generic properties of the motors, cargos, and filaments, so they should apply to other motors as well

    Epizootiological Survey of the Isle Russian and Measures Necessary for the Prophylaxis of Tick-Born Infections among Population of the Region and Participants of APEC Summit

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    In spring, 2011 within the frames of epizootiological survey of the Isle Russian territory, identified were five species of Ixodic ticks: Ixodes persulcatus, I. pavlovskyi, Haemaphysalis concinna, H. japonica douglasi, Dermacentor silvarum. Those ticks were infected with the agents of tick-born encephalitis, borreliosis, rickettsiosis, and monocytic ehrlichiosis. Further preparations for the hosting of APEC Summit in the territory of the Isle in September 2012 involve large-scale construction of various facilities, transformation of natural biotopes, and significant increase in population numbers both permanently and temporally residing in the region. In this connection, a complex of preventive measures aimed at protection of local population and participants of the Summit from tick-borne infections is currently under consideration

    Analysis of Epidemiological Situation on Hemorrhagic Fever with Renal Syndrome in the Khabarovsk Territory and the Jewish Autonomous Region, and Prognosis of Its Development for the Past-Flood Period in 2013-2014

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    Complex analysis of the data concerning epidemiological situation on HFRS in the Khabarovsk Territory and the Jewish Autonomous Region for the past decade (2003-2012) previous to high water in 2013 and results of operative epidemiological inspection of the flooding area and the adjoining territory where a high index of laboratory evidences of the virus presence in the main carriers was revealed, outlines high probability of the epidemiological condition complications in view of the infection in the post-flooding period in 2013-2014 in the both entities. Therewith on the basis of the unfavorable prognosis for the epidemiological situation development a Plan of organizational, preventive and anti-epidemic measures directed to minimization of risks related to aggravation of epidemiological situation on hemorrhagic fever with renal syndrome has been developed and is being implemented

    Investigations of Structural-Functional Aspects of Epizootic Process in Natural Plague Foci in Siberia

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    Comprehensively studied have been structural elements of ecosystems of Siberian natural plague foci, as well as levels of integration among epizootic process components, and ways of their functional interaction. Application of the complex approach to the surveillance over structural-functional elements of the parasitic system along with investigations of epizootic process dynamics has provided for identification of peculiarities as regards epizootics development, transformation and evolution of population and carrier/vector coenosis structure in time and space. Revealed is the genetic diversity of plague microbe circulating within the bounds of separate foci and zones of focality. Determined is a long-lasting anti-epidemic effect (more than 20 years) of the field desinsection in the Saglinsk meso-focus of the Tuva natural plague focus

    Assessment of Epizootiological-Epidemiological Situation on Natural Focal Infections in Aleksandrovsk-Sakhalin Territory of the Sakhalin Region

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    Objective of the work was to carry out complex assessment of the current state of epizootic activity and epidemiological significance of the infectious disease natural foci in the Aleksandrovsk-Sakhalin territory of the Sakhalin Region. Trapped were 56 samples of small mammals in July, 2010; collected were 180 specimens of taiga tick imago, caught were 1000 specimens of mosquitoes. 223 samples of blood sera were taken from residents of the region. All the field data were tested to detect specific antibodies, antigens and genetic material of agents. Based on the results of epizootiological investigations, serological and molecular-genetic assays, demonstrated was the occurence of natural foci of leptospirosis, tularemia, tick-borne encephalitis, borreliosis, rickettsiosis, human granulocytic anaplasmosis, human monocytic ehrlichiosis, West Nile fever, Inco fever, Batai and Geto fevers, as well as HFRS with varying degree of activity manifestation in the territory of the region. Isolated was tick-borne encephalitis virus from mosquitoes
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