1,142 research outputs found

    Decomposition rates of aspen bole and branch litter

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    Molten salt dynamics in glass melts using millimeter-wave emissivity measurements

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    The Similarity of Husbands' and Wives' Political Views

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67973/2/10.1177_1532673X7700500202.pd

    The 13-C(p,d) Reaction at 120 MeV

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    This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440

    How spiking neurons give rise to a temporal-feature map

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    A temporal-feature map is a topographic neuronal representation of temporal attributes of phenomena or objects that occur in the outside world. We explain the evolution of such maps by means of a spike-based Hebbian learning rule in conjunction with a presynaptically unspecific contribution in that, if a synapse changes, then all other synapses connected to the same axon change by a small fraction as well. The learning equation is solved for the case of an array of Poisson neurons. We discuss the evolution of a temporal-feature map and the synchronization of the single cells’ synaptic structures, in dependence upon the strength of presynaptic unspecific learning. We also give an upper bound for the magnitude of the presynaptic interaction by estimating its impact on the noise level of synaptic growth. Finally, we compare the results with those obtained from a learning equation for nonlinear neurons and show that synaptic structure formation may profit from the nonlinearity

    Congruence between Voters and Parties:The Role of Party-Level Issue Salience

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    First published online: 25 February 2020The level of congruence between parties and their voters can vary greatly from one policy issue to another, which raises questions regarding the effectiveness of political representation. We seek to explain variation in party–voter congruence across issues and parties. We focus on the hypotheses that (1) average proximity between the positions of voters and the party they vote for will be highest on the issues that the party emphasises in the election campaign and that (2) this relationship will be stronger for niche parties. We test these hypotheses using data on the policy preferences of voters, party positions, party attention profiles and salience on concrete policy issues in four countries: The Netherlands, Ireland, Germany and Sweden. Overall, we find that voter–party proximity tends to be higher on issues that the party emphasises. As these are the issues where parties typically have the greatest policy impact, this implies that the quality of representation is highest where it matters most. There is some limited evidence that the positive relationship between issue salience and proximity is stronger for niche parties. In sum, the quality of policy representation varies strongly with party-level issue salience and to a lesser extent with the type of political party

    Nitrosative stress treatment of E. coli targets distinct set of thiol-containing proteins

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    Reactive nitrogen species (RNS) function as powerful antimicrobials in host defence, but so far little is known about their bacterial targets. In this study, we set out to identify Escherichia coli proteins with RNS-sensitive cysteines. We found that only a very select set of proteins contain cysteines that undergo reversible thiol modifications upon nitric oxide (NO) treatment in vivo . Of the 10 proteins that we identified, six (AtpA, AceF, FabB, GapA, IlvC, TufA) have been shown to harbour functionally important thiol groups and are encoded by genes that are considered essential under our growth conditions. Media supplementation studies suggested that inactivation of AceF and IlvC is, in part, responsible for the observed NO-induced growth inhibition, indicating that RNS-mediated modifications play important physiological roles. Interestingly, the majority of RNS-sensitive E. coli proteins differ from E. coli proteins that harbour H 2 O 2 -sensitive thiol groups, implying that reactive oxygen and nitrogen species affect distinct physiological processes in bacteria. We confirmed this specificity by analysing the activity of one of our target proteins, the small subunit of glutamate synthase. In vivo and in vitro activity studies confirmed that glutamate synthase rapidly inactivates upon NO treatment but is resistant towards other oxidative stressors.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72397/1/j.1365-2958.2007.05964.x.pd
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