293 research outputs found

    Temporal Patterns of Gene Expression in the MNTB During Calyx of Held Development

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    Brain development is inextricably linked to changes in gene expression. Providing insight into the mechanisms controlling these complex events is a current challenge in neuroscience. Neurons in the medial nucleus of the trapezoid body (MNTB) receive large specialized glutamatergic nerve terminals, the calyces of Held, which grow very quickly between postnatal day 2 (P2) and P4. Through both quantitative real-time PCR (qPCR) and microarray analysis, we examined the gene expression over time for a select group of voltage-gated potassium channels controlling ion channel function and composition to finely tune their biophysical properties. Low threshold activated potassium channels subunits Kv1.1 (Kcna1) and Kv1.2 (Kcna2) both increase between P0 and P6. However, between P6 and P14, Kcna1 continues to increase while Kcna2 stays more constant. Delayed rectifier potassium channels (Kv3 family), Kv3.1 (Kcnc1) levels increase slowly between P0 and P14 while Kv3.3 (Kcnc3) levels are stable between P0 and P6 followed by a sharp increase between P6 and P14. Hcn2, a member of the hyperpolarization-activated and cyclic nucleotide-gated channel family controlling hyperpolarization-activated current (IH), also showed stable expression between P0 and P6 followed by an increase between P6 and P14. These data suggest that potassium channel composition changes dynamically during early postnatal development of the MNTB.;We next characterized the genome-wide changes in the MNTB/calyx of Held developmental system utilizing microarrays and dense temporal sampling at ages surrounding growth of the calyceal inputs between P0 and P6. We identified a list of 541 significantly changing genes and clustered them into eight groups based upon their temporal expression profiles. Candidates originating from each of the profile groups were validated by qPCR and showed excellent correlation between both techniques. Many of the changing transcripts are associated with astrocytes and oligodendrocytes in addition to the neuronal contribution. Gene ontology revealed enrichment of genes involved in axon pathfinding and cell adhesion. These results provide a genetic framework for future investigation of mechanisms associated with nerve terminal growth and maturation

    The Texas banking crisis and the payments system

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    The Federal Reserve System plays a crucial role in the payments system that is especially important during periods of financial turmoil. In this article, Robert Clair, Joanna Kolson, and Kenneth Robinson explain the process and the risks involved in clearing checks in the private sector. They compare these processes and risks with the essentially risk-free check-clearing service the Federal Reserve System offers. During banking crises, they hypothesize, banks will increase their check-clearing through the Federal Reserve to minimize their risk exposure. A model of Federal Reserve check-clearing volume is constructed and estimated. The empirical results show that during banking crises, Federal Reserve check- processing volume rises as banks seek safer methods of clearing checks. Consequently, Federal Reserve payment services are important tools in minimizing the disruptive effects of banking crises on the economy.Banks and banking - Texas ; Payment systems

    Voluntary Relinquishment of American Citizenship a Proposed Definition

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    History, scale and the political ecology of ethical diamonds in Kugluktuk, Nunavut

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    Canadian diamonds are marketed as ethical alternatives to so-called 'conflict diamonds.' This research analyzes a series of focus groups conducted in Kugluktuk, Nunavut, an Inuit town impacted by diamond mining. The article sheds some light on the risks and benefits of mining, but it also examines the broader historical and geographic context of commodity networks for diamonds as an entry point into a critique of the possibility of consumption as ethical praxis. What the analysis shows is that the risks and benefits assessed by focus group participants manifest themselves in a context of colonial dispossession of sovereignty over resources. This dispossession is part of the very process of market regulation that is necessary for capital accumulation. Accumulated capital professes to satisfy this created need ethically. In much of Arctic Canada, for example, this takes the form of a dependency on the market in order to secure the wages now necessary to engage in subsistence activities. The purpose of this article is not to unveil exploitive conditions of production or to claim that Canadian diamonds are in fact unethical, but rather to question what we mean by 'ethical' commodities by examining the claim within a broader historical political ecology. Keywords: Diamonds, political ecology, market regulation, Nunavut, ethical consumption

    N2 year in review and message from the editor to our reviewers

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    N2 year in review

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    Power Grid Politics: Winter Storm Uri and Texas Governor Greg Abbott\u27s Image Repair Discourse

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    Winter storm Uri hit the state of Texas on February 14, 2021. Bringing record amounts of snow, ice, and prolonged sub-zero temperatures, the storm caused widespread power outages which led to hundreds of deaths, and created a complex rhetorical situation for Governor Greg Abbott. This article examines the image repair discourse engaged in by Abbott, and ultimately concludes that his use of blame-shifting, corrective action, and defeasibility strategies were ultimately effective, but to varying degrees based on each respective strategy. We argue herein that Abbott’s strategy of shifting the blame for the debacle to ERCOT was his most effective tactic, while his reliance on corrective action approaches (while necessary and expected by the audience) were only marginally persuasive. Abbott’s defeasibility strategy was undercut both by conflicting statements, and by the recent reality that Texas does, in fact, experience extreme weather events however rare. We also argue that severe weather events are likely to become more frequent in the future, and that Texas in particular will be uniquely impacted by these storms due to climate change. We conclude that the political fortunes of elected officials will increasingly depend on how they justify their response to these cataclysmic storms
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