28,265 research outputs found

    Initial behavioural and attitudinal responses to influenza A, H1N1 ('swine flu')

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    Copyright © 2010 by the BMJ Publishing Group Ltd. All rights reserved.This study was sponsored by Canadian Institute of Health Research (CIHR), and supported by the Community Coalition Concerned about SARS and other community organisations in the great Toronto area

    Time Zones As Cues For Coordination: Latitude, Longitude, And Letterman

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    Market productivity is often greater, and leisure and other household activities more enjoyable, when people perform them simultaneously. Beyond pointing out the positive externalities of synchronicity, economists have not attempted to identify exogenous determinants of timing. We develop a theory illustrating conditions under which synchronicity will vary and identify three factors — the amount of daylight, the timing of television programming, and differences in time zones — that can alter timing. Using the American Time Use Survey for 2003 and 2004, we first show that an exogenous shock to time in one area due to non-adherence to daylight-saving time leads its residents to alter their work schedules to continue coordinating their activities with those of people elsewhere. With time use data from Australia, we also demonstrate the same response to a similar shock there. We then show that both television timing and the benefits of coordinating across time zones in the U.S. generally affect the timing of market work and sleep, the two most time-consuming activities people undertake. While these impacts do not differ greatly by people's demographic characteristics,workers in industries where we would expect more coordination outside of their local areas are more responsive to the effects of time zones.banking, market discipline

    Use of ERTS data for a multidisciplinary analysis of Michigan resources

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    There are no author-identified significant results in this report

    Time Zones as Cues for Coordination: Latitude, Longitude, and Letterman

    Get PDF
    Market productivity is often greater, and leisure and other household activities more enjoyable, when people perform them simultaneously. Beyond pointing out the positive externalities of synchronicity, economists have not attempted to identify exogenous determinants of timing. We develop a theory illustrating conditions under which synchronicity will vary and identify three factors %u2014 the amount of daylight, the timing of television programming, and differences in time zones %u2014 that can alter timing. Using the American Time Use Survey for 2003 and 2004, we first show that an exogenous shock to time in one area due to non-adherence to daylight-saving time leads its residents to alter their work schedules to continue coordinating their activities with those of people elsewhere. With time use data from Australia, we also demonstrate the same response to a similar shock there. We then show that both television timing and the benefits of coordinating across time zones in the U.S. generally affect the timing of market work and sleep, the two most time-consuming activities people undertake. While these impacts do not differ greatly by people's demographic characteristics, workers in industries where we would expect more coordination outside of their local areas are more responsive to the effects of time zones.

    Write-limited sorts and joins for persistent memory

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    To mitigate the impact of the widening gap between the memory needs of CPUs and what standard memory technology can deliver, system architects have introduced a new class of memory technology termed persistent memory. Persistent memory is byteaddressable, but exhibits asymmetric I/O: writes are typically one order of magnitude more expensive than reads. Byte addressability combined with I/O asymmetry render the performance profile of persistent memory unique. Thus, it becomes imperative to find new ways to seamlessly incorporate it into database systems. We do so in the context of query processing. We focus on the fundamental operations of sort and join processing. We introduce the notion of write-limited algorithms that effectively minimize the I/O cost. We give a high-level API that enables the system to dynamically optimize the workflow of the algorithms; or, alternatively, allows the developer to tune the write profile of the algorithms. We present four different techniques to incorporate persistent memory into the database processing stack in light of this API. We have implemented and extensively evaluated all our proposals. Our results show that the algorithms deliver on their promise of I/O-minimality and tunable performance. We showcase the merits and deficiencies of each implementation technique, thus taking a solid first step towards incorporating persistent memory into query processing. 1

    The Vaporization of B2O3(l) to B2O3(g) and B2O2(g)

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    The vaporization of B2O3 in a reducing environment leads to formation of both B2O3(g) and B2O2(g). While formation of B2O3(g) is well understood, many questions about the formation of B2O2(g) remain. Previous studies using B(s) + B2O3(l) have led to inconsistent thermodynamic data. In this study, it was found that after heating, B(s) and B2O3(l) appear to separate and variations in contact area likely led to the inconsistent vapor pressures of B2O2(g). To circumvent this problem, an activity of boron is fixed with a two-phase mixture of FeB and Fe2B. Both second and third law enthalpies of formation were measured for B2O2(g) and B2O3(g). From these the enthalpies of formation at 298.15 K are calculated to be -479.9 +/- 41.5 kJ/mol for B2O2(g) and -833.4 +/- 13.1 kJ/mol for B2O3(g). Ab initio calculations to determine the enthalpies of formation of B2O2(g) and B2O3(g) were conducted using the W1BD composite method and show good agreement with the experimental values

    Abundant cyanopolyynes as a probe of infall in the Serpens South cluster-forming region

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    We have detected bright HC7N J = 21-20 emission toward multiple locations in the Serpens South cluster-forming region using the K-Band Focal Plane Array at the Robert C. Byrd Green Bank Telescope. HC7N is seen primarily toward cold filamentary structures that have yet to form stars, largely avoiding the dense gas associated with small protostellar groups and the main central cluster of Serpens South. Where detected, the HC7N abundances are similar to those found in other nearby star forming regions. Toward some HC7N `clumps', we find consistent variations in the line centroids relative to NH3 (1,1) emission, as well as systematic increases in the HC7N non-thermal line widths, which we argue reveal infall motions onto dense filaments within Serpens South with minimum mass accretion rates of M ~ 2-5 M_sun Myr^-1. The relative abundance of NH3 to HC7N suggests that the HC7N is tracing gas that has been at densities n ~ 10^4 cm^-3, for timescales t < 1-2 x 10^5 yr. Since HC7N emission peaks are rarely co-located with those of either NH3 or continuum, it is likely that Serpens South is not particularly remarkable in its abundance of HC7N, but instead the serendipitous mapping of HC7N simultaneously with NH3 has allowed us to detect HC7N at low abundances in regions where it otherwise may not have been looked for. This result extends the known star-forming regions containing significant HC7N emission from typically quiescent regions, like the Taurus molecular cloud, to more complex, active environments.Comment: 19 pages, 13 figures, accepted to MNRAS. Version with full resolution figures available at http://www.dunlap.utoronto.ca/~friesen/Friesen_HC7N.pd

    Black Hole Production by Cosmic Rays

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    Ultra-high energy cosmic rays create black holes in scenarios with extra dimensions and TeV-scale gravity. In particular, cosmic neutrinos will produce black holes deep in the atmosphere, initiating quasi-horizontal showers far above the standard model rate. At the Auger Observatory, hundreds of black hole events may be observed, providing evidence for extra dimensions and the first opportunity for experimental study of microscopic black holes. If no black holes are found, the fundamental Planck scale must be above 2 TeV for any number of extra dimensions.Comment: 4 pages, 4 figures, PRL versio

    Development of computer software to analyze entire LANDSAT scenes and to summarize classification results of variable-size polygons

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    The Forest Pest Management Division (FPMD) of the Pennsylvania Bureau of Forestry has the responsibility for conducting annual surveys of the State's forest lands to accurately detect, map, and appraise forest insect infestations. A standardized, timely, and cost-effective method of accurately surveying forests and their condition should enhance the probability of suppressing infestations. The repetitive and synoptic coverage provided by LANDSAT (formerly ERTS) makes such satellite-derived data potentially attractive as a survey medium for monitoring forest insect damage over large areas. Forest Pest Management Division personnel have expressed keen interest in LANDSAT data and have informally cooperated with NASA/Goddard Space Flight Center (GSFC) since 1976 in the development of techniques to facilitate their use. The results of this work indicate that it may be feasible to use LANDSAT digital data to conduct annual surveys of insect defoliation of hardwood forests
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