283 research outputs found

    Refinement of Kripke Models for Dynamics

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    We propose a property-preserving refinement/abstraction theory for Kripke Modal Labelled Transition Systems incorporating not only state mapping but also label and proposition lumping, in order to have a compact but informative abstraction. We develop a 3-valued version of Public Announcement Logic (PAL) which has a dynamic operator that changes the model in the spirit of public broadcasting. We prove that the refinement relation on static models assures us to safely reason about any dynamic properties in terms of PAL-formulas on the abstraction of a model. The theory is in particular interesting and applicable for an epistemic setting as the example of the Muddy Children puzzle shows, especially in the view of the growing interest for epistemic modelling and (automatic) verification of communication protocols

    Strategies to Gain International Recognition: Iraqi Kurdistan's September 2017 Referendum for Independence

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    Despite the growing interest in the study of de facto states, our understanding of the conditions under which these entities construct and change strategies to gain international recognition remains partial. The aim of this article is to answer the following questions: firstly, what strategies did the Kurdistan Region of Iraq adopt in its pursuit of international recognition? And secondly, what internal and external dynamics are responsible for changing these recognition strategies? To do so, we analyse 68 speeches, interviews and statements from former KRI President Masoud Barzani, from the public announcement of an independence referendum on 7 June 2017 to the holding of the referendum on 25 September 2017, looking into his arguments for independence and how internal and external dynamics have shaped the KRI's recognition strategies. Drawing on the case of the KRI, the article tries to provide insights into how de facto states construct their arguments for statehood.Security and Global Affair

    Техніка і технологія збагачення корисних копалин

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    Викладені теоретичні основи і технологія процесів збагачення корисних копалин. Розглянуті основні конструкції технологічного обладнання, його принцип дії і технологічні характеристики. Викладені методи контролю технологічного процесу і базисні положення охорони навколишнього середовища. Навчальний посібник відповідає програмі навчальної дисципліни "Техніка і технологія переробки гірських порід", призначений для здобувачів ступеня бакалавра за спеціальністю 184 "Гірництво" та буде корисним фахівцям з гірничо-видобувних підприємств

    Risicoprofilering heronderzoek bijstandsuitkering = Risk profiling for social welfare re-examination

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    Normative advice commissionAbderrahman El Aazani, Researcher at the Ombudsman Rotterdam-RijnmondFrancien Dechesne, Associate Professor Law and Digital Technologies, Leiden UniversityMaarten van Asten, Alderman Finance, Digitalization, Sports and Events Municipality of TilburgMunish Ramlal, Ombudsman Metropole region AmsterdamOskar Gstrein, Assistant Professor Governance and Innovation, University of GroningenEffective Protection of Fundamental Rights in a pluralist worl

    Neochloris oleoabundans cell walls have an altered composition when cultivated under different growing conditions

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    The impact that environmental factors have on the intracellular components of microalgae has been the focus of research for a number of decades. Despite that, their effects on the cell wall have received very little attention. In this study, we investigated how different growing conditions affect the cell walls of N. oleoabundans. The results revealed that the cell wall composition varied in that the modifications were different in the four cultivation media: freshwater nitrogen-replete (optimum culture) and -depleted conditions, and seawater nitrogen-replete and -depleted conditions. Nitrogen deficiency in freshwater cultivation was the only condition that significantly (p <.05) increased the total content of carbohydrates in the cell wall. The three most abundant components of freshwater-cultivated cell wall polysaccharides were rhamnose, galactose and glucuronic acid whereas in seawater media the main components of cell wall polysaccharides were rhamnose, glucose and galactose. The combined results of the biochemical analyses and monoclonal antibodies epitope-binding revealed that N. oleoabundans cell walls are likely composed of sulphated polysaccharides enriched in mannose, β-(1 → 4)-D-mannans, and glucose as they grow in seawater. Salinity and nitrogen deficiency also had an impact on the nitrogenous components of the cell wall. Under these conditions we observed a decrease in glucosamine in the cell wall. The analysis of specific binding of monoclonal antibodies, revealed that the cell wall of N. oleoabundans is possibly enriched in arabinogalactan proteins (AGPs). Under salinity and nitrogen deficiency N. oleoabundans increased the proportion of the non-polar to polar amino acids in the cell walls. An increase of leucine in the cell walls may suggest that N. oleoabundans contains leucine-rich repeat proteins which are known to play a vital role in stress responses. This report provides new insights into microalgae cell wall biology and how cell walls are remodelled when growing under different conditions.</p

    Nanopods: A New Bacterial Structure and Mechanism for Deployment of Outer Membrane Vesicles

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    Background: Bacterial outer membrane vesicles (OMV) are packets of periplasmic material that, via the proteins and other molecules they contain, project metabolic function into the environment. While OMV production is widespread in proteobacteria, they have been extensively studied only in pathogens, which inhabit fully hydrated environments. However, many (arguably most) bacterial habitats, such as soil, are only partially hydrated. In the latter, water is characteristically distributed as films on soil particles that are, on average thinner, than are typical OMV (ca. ≤10 nm water film vs. 20 to >200 nm OMV;). Methodology/Principal Findings: We have identified a new bacterial surface structure, termed a "nanopod", that is a conduit for projecting OMV significant distances (e.g., ≥6 µm) from the cell. Electron cryotomography was used to determine nanopod three-dimensional structure, which revealed chains of vesicles within an undulating, tubular element. By using immunoelectron microscopy, proteomics, heterologous expression and mutagenesis, the tubes were determined to be an assembly of a surface layer protein (NpdA), and the interior structures identified as OMV. Specific metabolic function(s) for nanopods produced by Delftia sp. Cs1-4 are not yet known. However, a connection with phenanthrene degradation is a possibility since nanopod formation was induced by growth on phenanthrene. Orthologs of NpdA were identified in three other genera of the Comamonadaceae family, and all were experimentally verified to form nanopods. Conclusions/Significance: Nanopods are new bacterial organelles, and establish a new paradigm in the mechanisms by which bacteria effect long-distance interactions with their environment. Specifically, they create a pathway through which cells can effectively deploy OMV, and the biological activity these transmit, in a diffusion-independent manner. Nanopods would thus allow environmental bacteria to expand their metabolic sphere of influence in a manner previously unknown for these organisms

    Soil aggregates as massively concurrent evolutionary incubators

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    Soil aggregation, a key component of soil structure, has mostly been examined from the perspective of soil management and the mediation of ecosystem processes such as soil carbon storage. However, soil aggregation is also a major factor to consider in terms of the fine-scale organization of the soil microbiome. For example, the physico-chemical conditions inside of aggregates usually differ from the conditions prevalent in the bulk soil and aggregates therefore increase the spatial heterogeneity of the soil. In addition, aggregates can provide a refuge for microbes against predation since their interior is not accessible to many predators. Soil aggregates are thus clearly important for microbial community ecology in soils (for example, Vos et al., 2013; Rillig et al., 2016) and for microbially driven biogeochemistry, and soil microbial ecologists are increasingly appreciating these aspects of soil aggregation. Soil aggregates have, however, so far been neglected when it comes to evolutionary considerations (Crawford et al., 2005) and we here propose that the process of soil aggregation should be considered as an important driver of evolution in the soil microbial community

    Visualizing the Needle in the Haystack: In Situ Hybridization With Fluorescent Dendrimers

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    In situ hybridization with 3DNA™ dendrimers is a novel tool for detecting low levels of mRNA in tissue sections and whole embryos. Fluorescently labeled dendrimers were used to identify cells that express mRNA for the skeletal muscle transcription factor MyoD in the early chick embryo. A small population of MyoD mRNA positive cells was found in the epiblast prior to the initiation of gastrulation, two days earlier than previously detected using enzymatic or radiolabeled probes for mRNA. When isolated from the epiblast and placed in culture, the MyoD mRNA positive cells were able to differentiate into skeletal muscle cells. These results demonstrate that DNA dendrimers are sensitive and precise tools for identifying low levels of mRNA in single cells and tissues
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