663 research outputs found

    Reconciling the Metallicity Distributions of Gamma-ray Burst, Damped Lyman-alpha, and Lyman-break Galaxies at z=3

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    We test the hypothesis that the host galaxies of long-duration gamma-ray bursts (GRBs) as well as quasar-selected damped Lyman-alpha (DLA) systems are drawn from the population of UV-selected star-forming, high-z galaxies (generally referred to as Lyman-break galaxies). Specifically, we compare the metallicity distributions of the GRB and DLA populations to simple models where these galaxies are drawn randomly from the distribution of star-forming galaxies according to their star-formation rate and HI cross-section respectively. We find that it is possible to match both observational distributions assuming very simple and constrained relations between luminosity, metallicity and HI sizes. The simple model can be tested by observing the luminosity distribution of GRB host galaxies and by measuring the luminosity and impact parameters of DLA selected galaxies as a function of metallicity. Our results support the expectation that GRB and DLA samples, in contrast to magnitude limited surveys, provide an almost complete census of z=3 star-forming galaxies that are not heavily dust-obscured.Comment: 31 pages, 6 figures. Accepted for publication in Ap

    DGNB building certification companion: Sustainability Tool for Assessment, Planning, Learning, and Engaging (STAPLE)

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    In the construction industry, the popularity of sustainability and its benefits have been on the rise in recent years. Alas, with various building sustainability assessment schemes on the market, there is still no single general method for a comprehensive and inclusive design and building process for sustainable buildings. The literature describes several barriers of entry preventing actors in the industry from seeking sustainability certifications and prioritizing design methods, supporting sustainability in greater numbers. In the newly developed tool, ā€œDGNB building certification companion: Sustainable Tool for Assessment, Planning, Learning, and Engaging (STAPLE)ā€, a new Excel-based, interactive, and iterative education focused platform is introduced, intended to engage dialog among stakeholders, building owners, and decision makers, and the assigned group team leaders, based on the five DGNB topics. In order to establish common levels of knowledge, terminology, and understanding for proper interdisciplinary discussions, which would result in suitable and timely decisions, personal and professional development is enabled by imbedded educational documents in multiple formats throughout the tool as plain-language, easily digestible summaries of various topics regarding sustainability and the DGNB certification scheme. The identified barriers are described in the tool followed by a solution to overcome them. The tool, tested at multiple stages of development and moulded by many individuals both within and outside of the sustainable building industry, has shown to achieve the primary goals of assessment of individualā€™s current knowledge, educating through multiple stages and formats, and the inspiring of conversation among team members through a graphical display of opinions. Based on user feedback, the conclusion was that this is a desired product on the market. This new approach is expected to dramatically reduce misunderstandings, conflicts, and mistakes during a sustainable design process, helping the design team plan a project to possibly obtain the highest DGNB score if desired and properly documented

    Towards a Notion of Distributed Time for Petri Nets

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    We set the ground for research on a timed extension of Petri nets where time parameters are associated with tokens and arcs carry constraints that qualify the age of tokens required for enabling. The novelty is that, rather than a single global clock, we use a set of unrelated clocks --- possibly one per place --- allowing a local timing as well as distributed time synchronisation. We give a formal definition of the model and investigate properties of local versus global timing, including decidability issues and notions of processes of the respective models

    Structural operational semantics for stochastic and weighted transition systems

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    We introduce weighted GSOS, a general syntactic framework to specify well-behaved transition systems where transitions are equipped with weights coming from a commutative monoid. We prove that weighted bisimilarity is a congruence on systems defined by weighted GSOS specifications. We illustrate the flexibility of the framework by instantiating it to handle some special cases, most notably that of stochastic transition systems. Through examples we provide weighted-GSOS definitions for common stochastic operators in the literature

    Edaravone leads to proteome changes indicative of neuronal cell protection in response to oxidative stress

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    Neuronal cell death, in neurodegenerative disorders, is mediated through a spectrum of biological processes. Excessive amounts of free radicals, such as reactive oxygen species (ROS), has detrimental effects on neurons leading to cell damage via peroxidation of unsaturated fatty acids in the cell membrane. Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) has been used for neurological recovery in several countries, including Japan and China, and it has been suggested that Edaravone may have cytoprotective effects in neurodegeneration. Edaravone protects nerve cells in the brain by reducing ROS and inhibiting apoptosis. To gain further insight into the cytoprotective effects of Edaravone against oxidative stress condition we have performed comparative two-dimensional gel electrophoresis (2DE)-based proteomic analyses on SH-SY5Y neuroblastoma cells exposed to oxidative stress and in combination with Edaravone. We showed that Edaravone can reverse the cytotoxic effects of H2O2 through its specific mechanism. We observed that oxidative stress changes metabolic pathways and cytoslceletal integrity. Edaravone seems to reverse the H2O2-mediated effects at both the cellular and protein level via induction of Peroxiredoxin-2. (C) 2015 Elsevier Ltd. All rights reserved
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