462 research outputs found

    Ecological features of cyanobacteria and algae communities of the littoral of the meromictic Lake Shira (Khakassia Republic, Russia)

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    During the study of cyanobacteria and algae from littoral of the meromictic Lake Shira (Republic of Khakas- sia, Russia) forty-eight taxa were identified: Cyanobacteria – 7, Chlorophyta – 5, and Bacillariophyta – 36 species. Cyanobacteria were represented by cosmopolitan taxa Leptolyngbya voronichiniana, cf. Trichocoleus hospitus and widely distributed in the freshwater ecosystems species Phormidium cf. paulsenianum, Pseudophormidium cf. golenkinianum, P. pauciramosum, Leptolyngbya perforans, and L. subtilissima. Among green algae typical freshwater taxa Chloroidium saccharophilum, Desmodesmus abundans, Oocystis lacustris, Chlorella sp., Stigeoclonium sp. were detected. Among Bacillariophyta the most frequent species were Amphora ovalis, Cymbella affinis, Encyonema silesiacum, Eunotia fallax, Gomphonella olivacea, G. parvulum, Kobayasiella subtilissima, Navicula minima, N. radiosa, N. veneta, Nitzchia fonti- cola, N. palea, Grunowia tabellaria, Surirella undulata. Several rare species cf. Fragilaria tenera, Grunowia tabellaria and cf. Ulnaria capitata were found. In relation to mineralization indifferents was the largest group (73%). In relation to pH, a unique feature of the investigated lake was the predominance of alkaliphilic species of diatoms (56%), such as Amphora ovalis, Cymbella affinis, Gomphonema truncatum, Hantzschia amphioxys, Navicula minima, N. veneta, Nitzschia cf. linearis, N. palea, Planothidium lanceolatum and other. In the geographic structure cosmopolitan group included 25 species (69%), boreal group – 4 species (11%), arcto-apline group – 2 species (6%). To obtain more accurate informa- tion on the biodiversity of cyanobacteria and algae of Lake Shira further studies using molecular-genetic and electron microscopic methods are needed

    Современный Интернет Вещей для Умных городов

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    The IoT concept combines a network of physical devices, transceivers and software which allows a user to manage these devices to perform various actions that will solve everyday problems of city residents. It allows exchanging data between devices, store and process data. Creating common IoT architecture is a difficult task since there is a problem of connecting heterogeneous devices with heterogeneous data transfer protocols. The challenge will be to create the right architecture for urban IoT and methods that will solve the common problem with heterogeneous data. This paper focuses on the practical use of IoT in an urban environment. Smart cities are based on the use of modern technologies for the implementation of certain administrative services. This practice allows creating unique services that allow city authorities to reduce costs, optimize and automate typical city processes. IoT allows municipalities to make citizens’ life better. In addition, this paper addresses the example of the IoT technical implementation in Padova Smart City. The urban IoT main goal is to make the Internet wider and more convenient for the life of people.Интернет Вещей (IoT) объединяет сеть физических устройств, транспортных узлов, программного обеспечения. Данная парадигма позволяет пользователю программировать устройства на выполнение определённых функций, которые позволят решить повседневные проблемы жителей города. Эта сеть позволяет обмениваться данными между устройствами, хранить и обрабатывать эти данные. Создание общей архитектуры IoT является сложной задачей, так как существует проблема подключения разнородных устройств с разнородными протоколами передачи данных. Будет затронута проблема создания правильной архитектуры для городского IoT и методов, которые позволят решить распространенную проблему с разнородными данными. Данная статья будет посвящена практическому использованию IoT в городской среде. Таким образом реализуется концепция Умных городов. Умные города основываются на использовании современных технологий для осуществления разнообразных административных услуг. Данная практика позволит создать уникальные сервисы, которые позволят городским органам снизить расходы, оптимизировать и автоматизировать типичные процессы города. IoT позволит муниципалитетам сделать жизнь граждан лучше. Кроме этого, данная статья затронет пример технической реализации IoT в городе Падуя. Основная цель IoT - сделать Интернет более широким и удобным для жизни людей

    Gene conversion in human rearranged immunoglobulin genes

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    Over the past 20 years, many DNA sequences have been published suggesting that all or part of the V<sub>H</sub> segment of a rearranged immunoglobulin gene may be replaced in vivo. Two different mechanisms appear to be operating. One of these is very similar to primary V(D)J recombination, involving the RAG proteins acting upon recombination signal sequences, and this has recently been proven to occur. Other sequences, many of which show partial V<sub>H</sub> replacements with no addition of untemplated nucleotides at the V<sub>H</sub>–V<sub>H</sub> joint, have been proposed to occur by an unusual RAG-mediated recombination with the formation of hybrid (coding-to-signal) joints. These appear to occur in cells already undergoing somatic hypermutation in which, some authors are convinced, RAG genes are silenced. We recently proposed that the latter type of V<sub>H</sub> replacement might occur by homologous recombination initiated by the activity of AID (activation-induced cytidine deaminase), which is essential for somatic hypermutation and gene conversion. The latter has been observed in other species, but not in human Ig genes, so far. In this paper, we present a new analysis of sequences published as examples of the second type of rearrangement. This not only shows that AID recognition motifs occur in recombination regions but also that some sequences show replacement of central sections by a sequence from another gene, similar to gene conversion in the immunoglobulin genes of other species. These observations support the proposal that this type of rearrangement is likely to be AID-mediated rather than RAG-mediated and is consistent with gene conversion

    Small ball probability, Inverse theorems, and applications

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    Let ξ\xi be a real random variable with mean zero and variance one and A=a1,...,anA={a_1,...,a_n} be a multi-set in Rd\R^d. The random sum SA:=a1ξ1+...+anξnS_A := a_1 \xi_1 + ... + a_n \xi_n where ξi\xi_i are iid copies of ξ\xi is of fundamental importance in probability and its applications. We discuss the small ball problem, the aim of which is to estimate the maximum probability that SAS_A belongs to a ball with given small radius, following the discovery made by Littlewood-Offord and Erdos almost 70 years ago. We will mainly focus on recent developments that characterize the structure of those sets AA where the small ball probability is relatively large. Applications of these results include full solutions or significant progresses of many open problems in different areas.Comment: 47 page

    Low-fidelity DNA synthesis by human DNA polymerase theta

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    Human DNA polymerase theta (pol θ or POLQ) is a proofreading-deficient family A enzyme implicated in translesion synthesis (TLS) and perhaps in somatic hypermutation (SHM) of immunoglobulin genes. These proposed functions and kinetic studies imply that pol θ may synthesize DNA with low fidelity. Here, we show that when copying undamaged DNA, pol θ generates single base errors at rates 10- to more than 100-fold higher than for other family A members. Pol θ adds single nucleotides to homopolymeric runs at particularly high rates, exceeding 1% in certain sequence contexts, and generates single base substitutions at an average rate of 2.4 × 10−3, comparable to inaccurate family Y human pol κ (5.8 × 10−3) also implicated in TLS. Like pol κ, pol θ is processive, implying that it may be tightly regulated to avoid deleterious mutagenesis. Pol θ also generates certain base substitutions at high rates within sequence contexts similar to those inferred to be copied by pol θ during SHM of immunoglobulin genes in mice. Thus, pol θ is an exception among family A polymerases, and its low fidelity is consistent with its proposed roles in TLS and SHM

    Elite opinion and foreign policy in post-communist Russia

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    Russian elite opinion on matters of foreign policy may be classified as ‘Liberal Westerniser’, ‘Pragmatic Nationalist’ and ‘Fundamentalist Nationalist’, terms that reflect longstanding debates about the country’s relationship with the outside world. An analysis of press statements and election manifestoes together with a programme of elite interviews between 2004 and 2006 suggests a clustering of opinion on a series of strategic issues. Liberal Westernisers seek the closest possible relationship with Europe, and favour eventual membership of the EU and NATO. Pragmatic Nationalists are more inclined to favour practical co-operation, and do not assume an identity of values or interests with the Western countries. Fundamentalist Nationalists place more emphasis on the other former Soviet republics, and on Asia as much as Europe, and see the West as a threat to Russian values as well as to its state interests. Each of these positions, in turn, draws on an identifiable set of domestic constituencies: Liberal Westernisers on the promarket political parties, Pragmatic Nationalists on the presidential administration and defence and security ministries, and Fundamentalist Nationalists on the Orthodox Church and Communists

    Building the Record of late Miocene to Pleistocene Explosive Activity in the Kurile-Kamchatka Volcanic Arc: Initial Results and Challenges

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    Large explosive eruptions are among the most extreme natural events and can produce hemispheric or even global catastrophic effects. One of the prerequisites of predicting future giant eruptions is the understanding of sizes and recurrence times of past similar events. Volcanism of the North Pacific arcs is highly explosive, which is attested by large nested calderas and numerous tephra layers in marine and terrestrial sediments..

    Impact of liquid metal surface on plasma-surface interaction in experiments with lithium and tin capillary porous systems

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    The lithium and tin capillary-porous systems (CPSs) were tested with steady-state plasma in the PLM plasma device which is the divertor simulator with plasma parameters relevant to divertor and SOL plasma of tokamaks. The CPS consists of tin/lithium tile fixed between two molybdenum meshs constructed in the module faced to plasma. Steady-state plasma load of 0.1 - 1 MW/m(2) on the CPS during more than 200 min was achieved in experiments on PLM which is a modeling far scrapeoff- layer and far zone of divertor plasma of a large tokamak. The heating of the CPS was controlled remotely including biasing technique which allows to regulate evaporated metal influx to plasma. After exposure, the materials of the tin and lithium CPSs were inspected and analyzed with optic and scanning electron micriscopy. Experiments have demonstrated sustainability of the tin and lithium CPSs to the high heat steady state plasma load expected in a large scale tokamak. The effect of evaporated lithium and tin on the plasma transport/radiation was studied with spectroscopy to evaluate changes of plasma properties and plasma-surface interaction

    Viral discovery and diversity in trypanosomatid protozoa with a focus on relatives of the human parasite <i>Leishmania</i>.

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    Knowledge of viral diversity is expanding greatly, but many lineages remain underexplored. We surveyed RNA viruses in 52 cultured monoxenous relatives of the human parasite &lt;i&gt;Leishmania&lt;/i&gt; ( &lt;i&gt;Crithidia&lt;/i&gt; and &lt;i&gt;Leptomonas&lt;/i&gt; ), as well as plant-infecting &lt;i&gt;Phytomonas&lt;/i&gt; &lt;i&gt;Leptomonas pyrrhocoris&lt;/i&gt; was a hotbed for viral discovery, carrying a virus (Leptomonas pyrrhocoris ostravirus 1) with a highly divergent RNA-dependent RNA polymerase missed by conventional BLAST searches, an emergent clade of tombus-like viruses, and an example of viral endogenization. A deep-branching clade of trypanosomatid narnaviruses was found, notable as &lt;i&gt;Leptomonas seymouri&lt;/i&gt; bearing Narna-like virus 1 (LepseyNLV1) have been reported in cultures recovered from patients with visceral leishmaniasis. A deep-branching trypanosomatid viral lineage showing strong affinities to bunyaviruses was termed " &lt;i&gt;Leishbunyavirus&lt;/i&gt; " (LBV) and judged sufficiently distinct to warrant assignment within a proposed family termed " &lt;i&gt;Leishbunyaviridae&lt;/i&gt; " Numerous relatives of trypanosomatid viruses were found in insect metatranscriptomic surveys, which likely arise from trypanosomatid microbiota. Despite extensive sampling we found no relatives of the totivirus &lt;i&gt;Leishmaniavirus&lt;/i&gt; (LRV1/2), implying that it was acquired at about the same time the &lt;i&gt;Leishmania&lt;/i&gt; became able to parasitize vertebrates. As viruses were found in over a quarter of isolates tested, many more are likely to be found in the &gt;600 unsurveyed trypanosomatid species. Viral loss was occasionally observed in culture, providing potentially isogenic virus-free lines enabling studies probing the biological role of trypanosomatid viruses. These data shed important insights on the emergence of viruses within an important trypanosomatid clade relevant to human disease
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