32,728 research outputs found

    Quasi-adiabatic Switching for Metal-Island Quantum-dot Cellular Automata

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    Recent experiments have demonstrated a working cell suitable for implementing the Quantum-dot Cellular Automata (QCA) paradigm. These experiments have been performed using metal island clusters. The most promising approach to QCA operation involves quasi-adiabatically switching the cells. This has been analyzed extensively in gated semiconductor cells. Here we present a metal island cell structure that makes quasi-adiabatic switching possible. We show how this permits quasi-adiabatic clocking, and enables a pipelined architecture.Comment: 40 preprint-style double-spaced pages including 16 figure

    Primer selection impacts specific population abundances but not community dynamics in a monthly time-series 16S rRNA gene amplicon analysis of coastal marine bacterioplankton.

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    Primers targeting the 16S small subunit ribosomal RNA marker gene, used to characterize bacterial and archaeal communities, have recently been re-evaluated for marine planktonic habitats. To investigate whether primer selection affects the ecological interpretation of bacterioplankton populations and community dynamics, amplicon sequencing with four primer sets targeting several hypervariable regions of the 16S rRNA gene was conducted on both mock communities constructed from cloned 16S rRNA genes and a time-series of DNA samples from the temperate coastal Santa Barbara Channel. Ecological interpretations of community structure (delineation of depth and seasonality, correlations with environmental factors) were similar across primer sets, while population dynamics varied. We observed substantial differences in relative abundances of taxa known to be poorly resolved by some primer sets, such as Thaumarchaeota and SAR11, and unexpected taxa including Roseobacter clades. Though the magnitude of relative abundances of common OTUs differed between primer sets, the relative abundances of the OTUs were nonetheless strongly correlated. We do not endorse one primer set but rather enumerate strengths and weaknesses to facilitate selection appropriate to a system or experimental goal. While 16S rRNA gene primer bias suggests caution in assessing quantitative population dynamics, community dynamics appear robust across studies using different primers

    How Parents Use Time and Money

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    [Excerpt] This article examines weekday resource allocation decisions of married couples with a husband employed full time and with children under 18. These decisions relate, among other things, to working for pay; doing unpaid household work; purchasing services such as childcare, laundry and drycleaning, and food away from home; and eating out. Information about spending decisions was obtained from the 2009 Consumer Expenditure Survey (CE) and information about time use was obtained from the 2009 American Time Use Survey (ATUS). Results show that, Regardless of employment status, wives were more likely than husbands to spend time in household activities. On an average weekday, married fathers spent more time working than married mothers did, even married mothers employed full time. The proportion of families reporting childcare expenses and the average amount spent by those reporting were highest for families with full-time working wives and lowest for families with wives not employed for pay. Consistent with other research, working-wife families did not spend more on housekeeping and laundry services than did families with wives not employed for pay. Families with full-time working wives spent the greatest dollar amount on food away from home, but there was no significant difference in spending between families with part-time working wives and families with wives not employed for pay

    An Annotated Checklist of Wisconsin Mutillidae (Hymenoptera)

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    A survey of Wisconsin velvet ants (Hymenoptera: Mutillidae) conducted from literature searches, collection inventories, and two years of field work (2001-2002) yielded 28 species in three subfamilies. Of these, 23 species (representing 82% of the Wisconsin fauna and a 460% increase in the known species richness) are new state species records, having not previously been recorded in the published literature from the state. The known distributions of all Wisconsin species are reported by region and county, along with pertinent phenological, natural history, and other collection information, when known
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