1,772 research outputs found

    Natural increase in the Baltic South and South-West

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    This article analyses the natural population increase (decrease) in the postcommunist part of Baltic Europe (the federated state of Mecklenburg-Western Pomerania, West Pomeranian, Pomeranian, and Warmian-Masurian Voivodeships, Lithuania, Latvia, Estonia, the Kaliningrad and Leningrad region, and the federal city of Saint Petersburg) in 2002-2011. The study uses standard methods of demographic analysis, the data provided by national statistical services and Eurostat. All regions analysed are characterised by a low stationary phase of the demographic transition model (DTM). The situation proves to be unfavourable in the Polish regions under consideration and highly unfavourable in the remaining area

    Unfulfilled Promise: Electrification and the Chicago, Milwaukee & St. Paul Railroad

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    During the late nineteenth century and early twentieth century electricity made inroads into American life. Industry used electricity to power machines. Homemakers utilized electric appliances such as irons and washing machines to perform household chores. Electric lighting was used in homes, factories, railroad stations, advertising, and on city streets. The promise of electricity transformed everyday life. Electricity also held the promise of making it easier to transport freight and passengers on steam railroads. Despite electricity\u27s superiority to steam, a few railroads decided to electrify because it was necessary. Only one railroad, the Chicago, Milwaukee, and St. Paul, electrified a major portion of its lines for economic reasons

    Quasiquartet CEF ground state with possible quadrupolar ordering in the tetragonal compound YbRu2_{2}Ge2_{2}

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    e have investigated the magnetic properties of YbRu2_{2}Ge2_{2} by means of magnetic susceptibility χ\chi(T), specific heat C(T) and electrical resistivity ρ\rho(T) measurements performed on flux grown single crystals. The Curie-Weiss behavior of χ\chi(T) along the easy plane, the large magnetic entropy at low temperatures and the weak Kondo like increase in ρ\rho(T) proves a stable trivalent Yb state. Anomalies in C(T), ρ\rho(T) and χ\chi(T) at T0_{0} = 10.2 K, T1_{1} = 6.5 K and T2_{2} = 5.7 K evidence complex ordering phenomena, T0_{0} being larger than the highest Yb magnetic ordering temperature found up to now. The magnetic entropy just above T0_{0} amounts to almost Rln4, indicating that the crystal electric field (CEF) ground state is a quasiquartet instead of the expected doublet. The behavior at T0_{0} is rather unusual and suggest that this transition is related to quadrupolar ordering, being a consequence of the CEF quasiquartet ground state. The combination of a quasiquartet CEF ground state, a high ordering temperature, and the relevance of quadrupolar interactions makes YbRu2_{2}Ge2_{2} a rather unique system among Yb based compounds.Comment: 11 pages, 5 figure, submitted to PRB rapi

    Compositional Falsification of Cyber-Physical Systems with Machine Learning Components

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    Cyber-physical systems (CPS), such as automotive systems, are starting to include sophisticated machine learning (ML) components. Their correctness, therefore, depends on properties of the inner ML modules. While learning algorithms aim to generalize from examples, they are only as good as the examples provided, and recent efforts have shown that they can produce inconsistent output under small adversarial perturbations. This raises the question: can the output from learning components can lead to a failure of the entire CPS? In this work, we address this question by formulating it as a problem of falsifying signal temporal logic (STL) specifications for CPS with ML components. We propose a compositional falsification framework where a temporal logic falsifier and a machine learning analyzer cooperate with the aim of finding falsifying executions of the considered model. The efficacy of the proposed technique is shown on an automatic emergency braking system model with a perception component based on deep neural networks

    Seeds Buffering for Information Spreading Processes

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    Seeding strategies for influence maximization in social networks have been studied for more than a decade. They have mainly relied on the activation of all resources (seeds) simultaneously in the beginning; yet, it has been shown that sequential seeding strategies are commonly better. This research focuses on studying sequential seeding with buffering, which is an extension to basic sequential seeding concept. The proposed method avoids choosing nodes that will be activated through the natural diffusion process, which is leading to better use of the budget for activating seed nodes in the social influence process. This approach was compared with sequential seeding without buffering and single stage seeding. The results on both real and artificial social networks confirm that the buffer-based consecutive seeding is a good trade-off between the final coverage and the time to reach it. It performs significantly better than its rivals for a fixed budget. The gain is obtained by dynamic rankings and the ability to detect network areas with nodes that are not yet activated and have high potential of activating their neighbours.Comment: Jankowski, J., Br\'odka, P., Michalski, R., & Kazienko, P. (2017, September). Seeds Buffering for Information Spreading Processes. In International Conference on Social Informatics (pp. 628-641). Springe

    Social media actions and interactions: The role of the Facebook and Twitter during the 2014 European Parliament elections in the 28 EU nations.

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    Most political parties across the democratic sphere have created their own spaces within social media. While ostensibly studies show that social media is being utilized by political parties to further their electoral goals, the uses of their social media profiles by visitors is largely beyond official control without devoting significant resources to moderation. This study will be the first to gather data that allows us to detect patterns of participation within and potentially across nations, but in particular within nations and across parties to determine the extent that visitors use social media to promote parties (through liking and sharing) or for entering comments on party posts or for entering into discussions with other visitors. We specifically seek to understand whether we can detect evidence of a political ecosystem in which visitors visit multiple party profiles, enter debates across differing profiles and so contribute to something that might resemble an informed and engaged public sphere

    The cryo-EM structure of a pannexin 1 reveals unique motifs for ion selection and inhibition

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    Pannexins are large-pore forming channels responsible for ATP release under a variety of physiological and pathological conditions. Although predicted to share similar membrane topology with other large-pore forming proteins such as connexins, innexins, and LRRC8, pannexins have minimal sequence similarity to these protein families. Here, we present the cryo-EM structure of a frog pannexin 1 (Panx1) channel at 3.0 A. We find that Panx1 protomers harbor four transmembrane helices similar in arrangement to other large-pore forming proteins but assemble as a heptameric channel with a unique constriction formed by Trp74 in the first extracellular loop. Mutating Trp74 or the nearby Arg75 disrupt ion selectivity whereas altering residues in the hydrophobic groove formed by the two extracellular loops abrogates channel inhibition by carbenoxolone. Our structural and functional study establishes the extracellular loops as important structural motifs for ion selectivity and channel inhibition in Panx1
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