314 research outputs found

    Functional Urban Regions in Hungary

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    The topics discussed in this paper include conceptual dimensions of the framework of functional urban regions and their planning applicability; delineation of those regions for Hungary based on the 1970 Census data; an analytical description of these regions from both the economic and demographic points of view; and a general survey of the trends of recent regional development processes observed in Hungary. The paper also discusses planning policy implications of the analysis and the relevant perspectives of the human settlement network systems in Hungary

    TRESK background potassium channel is not gated at the helix bundle crossing near the cytoplasmic end of the pore.

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    Two-pore domain K+ channels (K2P) are responsible for background K+ currents and regulate the resting membrane potential and cellular excitability. Their activity is controlled by a large variety of physicochemical factors and intracellular signaling pathways. The majority of these effects converge on the intracellular C-terminus of the channels, resulting in the modification of the gating at the selectivity filter. Another gating mechanism, the activation gate at the helix bundle crossing is also well documented in other K+ channel families, however, it remains uncertain whether this type of gating is functional in K2P channels. The regulation of TWIK-related spinal cord K+ channel (TRESK) is different from the other K2P channels. Regulatory factors acting via the C-terminus are not known, instead channel activity is modified by the phosphorylation/dephosphorylation of the unusually long intracellular loop between the 2nd and 3rd transmembrane segments. These unique structural elements of the regulation lead us to examine channel gating at the bundle crossing region. Ba2+ was applied to the intracellular side of excised membrane patches and the characteristics of the channel block were determined. We compared the kinetics of the development of Ba2+ block when the channels were phosphorylated (inhibited) or dephosphorylated (activated) and also in different mutants mimicking the two functional states. Neither the phosphorylation/dephosphorylation nor the point mutations influenced the development of Ba2+ block, suggesting that the conformational changes of the bundle crossing region do not contribute to the phosphorylation-dependent gating of TRESK

    Cyclic AMP-dependent protein kinase and Ca2+-calmodulin stimulate the formation of polyphosphoinositjdes in a sarcoplasmic reticulum preparation of rabbit heart

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    AbstractA rabbit heart membrane fraction enriched in sarcoplasmic reticulum was incubated in a reaction mixture containing [γ-32P]ATP. The catalytic subunit of cyclic AMP-dependent protein kinase enhanced the 32P-labelling of both phosphatidylinositol-4-phosphate and phosphatidylinositol-4,5-bisphosphate. Ca2+-calmodulin also increased the 32P-incorporation into both polyphosphoinositides. Upon SDS gel-electrophoretic analysis of the membrane proteins, phospholamban was found to be concurrently phosphorylated by the exogenous catalytic subunit as well as by an endogenous Ca2+-calmodulm-dependent protein kinase

    Towards microagent based DBIST/DBISR

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    We present some ideas and experiments on using microagents for testing and repairing a distributed system, whose elements may or may not have embedded BIST (built in self test) and BISR (built in self repair) facilities. The microagents are software modules that perform monitoring, diagnosis and repair of the faults. They form together a society whose members communicate, set goals and solve tasks. The platforms taken into consideration for mobile tester microagents include Java Micro Edition, BREW, Symbian, PalmOS, as well as more general small scale platforms. Experimental tester agents in Java 2 Micro Edition and PalmOS are also presented, a solution that ensures portability, flexibility, but also a relatively small memory footprint

    It’s been mostly about money!: a multi-method research approach to the sources of institutionalization

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    Although much has been written about the process of party system insti- tutionalization in different regions, the reasons why some party systems institutionalize while others do not still remain a mystery. Seeking to fill this lacuna in the literature, and using a mixed-methods research approach, this article constitutes a first attempt to answer simultaneously the following three questions: (1) What specific factors help party systems to institutio- nalize (or not)? (2) What are the links (in terms of time and degree) as well as the causal mechanisms behind such relationships? and (3) how do they affect a particular party system? In order to do so, this article focuses on the study of party system development and institutionalization in 13 postcommunist democracies between 1990 and 2010. Methodologically, the article innovates in five respects. First, it continues the debate on the importance of ‘‘mixed methods’’ when trying to answer different research questions. Second, it adds to the as yet brief literature on the combination of process tracing and qualitative comparative analysis. Third, it constitutes the first attempt to date to use a most similar different outcome/most different same outcome pro- cedure in order to reduce causal complexity before undertaking a crisp-set qualitative comparative analysis. Third, it also shows the merits of combining both congruence and process tracing in the same comparative study. Finally, it also develops a novel ‘‘bipolar comparative method’’ to explain the extent to which opposite outcomes are determined by reverse conditions and conflicting intervening causal forces

    High Availability in the Future Internet

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    With the evolution of the Internet, a huge number of real- time applications, like Voice over IP, has started to use IP as primary transmission medium. These services require high availability, which is not amongst the main features of today’s heterogeneous Internet where fail- ures occur frequently. Unfortunately, the primary fast resilience scheme implemented in IP routers, Loop-Free Alternates (LFA), usually does not provide full protection against failures. Consequently, there has been a growing interest in LFA-based network optimization methods, aimed at tuning some aspect of the underlying IP topology to maximize the ratio of failure cases covered by LFA. The main goal of this chapter is to give a comprehensive overview of LFA and survey the related LFA network op- timization methods, pointing out that these optimization tools can turn LFA into an easy-to-deploy yet highly effective IP fast resilience scheme

    Party system closure and openness: conceptualization, operationalization and validation

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    The degree of closure of the governmental arena is a central aspect of the stabilization of party systems, and yet little systematic effort has been devoted to its operationalization. The article proposes a new index, examines its reliability and validity, and reports the ranking of 60 party systems. By redefining the units of measurement we suggest new indicators that are uniform and transparent in their logic of construction, can be applied both to specific government-changes and to time periods, and are sensitive to the degree of change. The article finds a hierarchy among the components of party system closure, dominated by coalition formula. While new and established democracies can both produced closed patterns, the analysis of inter-war European party systems shows that closed systems are less prone to authoritarian takeover. The article demonstrates the power of inertia: the completely closed configurations stand out as the most durable ones

    Intelligent image-based in situ single-cell isolation

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    Quantifying heterogeneities within cell populations is important for many fields including cancer research and neurobiology; however, techniques to isolate individual cells are limited. Here, we describe a high-throughput, non-disruptive, and cost-effective isolation method that is capable of capturing individually targeted cells using widely available techniques. Using high-resolution microscopy, laser microcapture microscopy, image analysis, and machine learning, our technology enables scalable molecular genetic analysis of single cells, targetable by morphology or location within the sample.Peer reviewe

    Molecular Background of Leak K+ Currents: Two-Pore Domain Potassium Channels

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    Enyedi P, Czirjak G. Molecular Background of Leak K+ Currents: Two-Pore Domain Potassium Channels. Physiol Rev 90: 559-605, 2010; doi:10.1152/physrev.00029.2009.-Two-pore domain K+ (K-2P) channels give rise to leak (also called background) K+ currents. The well-known role of background K+ currents is to stabilize the negative resting membrane potential and counterbalance depolarization. However, it has become apparent in the past decade (during the detailed examination of the cloned and corresponding native K-2P channel types) that this primary hyperpolarizing action is not performed passively. The K-2P channels are regulated by a wide variety of voltage-independent factors. Basic physicochemical parameters (e. g., pH, temperature, membrane stretch) and also several intracellular signaling pathways substantially and specifically modulate the different members of the six K-2P channel subfamilies (TWIK, TREK, TASK, TALK, THIK, and TRESK). The deep implication in diverse physiological processes, the circumscribed expression pattern of the different channels, and the interesting pharmacological profile brought the K-2P channel family into the spotlight. In this review, we focus on the physiological roles of K-2P channels in the most extensively investigated cell types, with special emphasis on the molecular mechanisms of channel regulation
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