1,373 research outputs found

    The relationship between IR, optical, and UV extinction

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    An analysis is presented for the variability of absolute IR, optical, and UV extinction, A(sub lambda), derived through the ratio of total-to-selective extinction, R, for 31 lines of sight for which reliable UV extinction parameters were derived. These data sample a wide range of environments and are characterized by 2.5 is less than or equal to R is less than or equal to 6.0. It was found that there is a strong linear dependence between extinction expressed as A(sub lambda)/A(sub V) and 1/R for 1.25 micron is less than or equal to lambda is less than or equal to 0.12 micron. Differences in the general shape of extinction curves are largely due to variations in shape of optical/near-UV extinction corresponding to changes in R, with A(sub lambda)/A(sub V) decreasing for increasing R. From a least-squares fit of the observed R-dependence as a function of wavelength for 0.8/micron is less than or greater than 1/lambda is less than or equal to 8.3/micron, an analytic expression was generated from which IR, optical, and UV extinction curves of the form A(sub lambda)/A(sub V) can be reproduced with reasonable accuracy from a knowledge of R. It was also found that the absolute bump strength normalized to A(sub V) shows a general decrease with increasing R, suggesting that some fraction of bump grains may be selectively incorporated into coagulated grains. Finally, it was found that absolute extinction normalized by suitably chosen color indices results in a minimization of the R-dependence of portions of the UV curve, allowing A(sub lambda) to be estimated for these wavelengths independent of R

    Decadal Growth of Traffic Volume on US Highway 2 in Northwestern Montana

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    We measured vehicle traffic volume at two locations on US Highway 2 along the southern boundary of Glacier National Park during 2012 and 2013 and then compared results to those collected during 1999 through 2001.  We show that traffic volumes have increased substantially in the 11 years between counts and that the increases are most dramatic during the hours in which grizzly bears (Ursus arctos) are most likely to cross the highway.  Over the preceding decade, grizzly bears have lost two hours of suitable crossing opportunity and will, should observed growth rates and traffic continue, lose an additional three hours within five years

    DNET: A communications facility for distributed heterogeneous computing

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    This document describes DNET, a heterogeneous data communications networking facility. DNET allows programs operating on hosts on dissimilar networks to communicate with one another without concern for computer hardware, network protocol, or operating system differences. The overall DNET network is defined as the collection of host machines/networks on which the DNET software is operating. Each underlying network is considered a DNET 'domain'. Data communications service is provided between any two processes on any two hosts on any of the networks (domains) that may be reached via DNET. DNET provides protocol transparent, reliable, streaming data transmission between hosts (restricted, initially to DECnet and TCP/IP networks). DNET also provides variable length datagram service with optional return receipts

    Use of mobile devices to answer online surveys: implications for research

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    BACKGROUND There is a growing use of mobile devices to access the Internet. We examined whether participants who used a mobile device to access a brief online survey were quicker to respond to the survey but also, less likely to complete it than participants using a traditional web browser. FINDINGS Using data from a recently completed online intervention trial, we found that participants using mobile devices were quicker to access the survey but less likely to complete it compared to participants using a traditional web browser. More concerning, mobile device users were also less likely to respond to a request to complete a six week follow-up survey compared to those using traditional web browsers. CONCLUSIONS With roughly a third of participants using mobile devices to answer an online survey in this study, the impact of mobile device usage on survey completion rates is a concern. TRIAL REGISTRATION ClinicalTrials.gov: NCT01521078

    Pragmatic randomized controlled trial of providing access to a brief personalized alcohol feedback intervention in university students

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    BACKGROUND There is a growing body of evidence indicating that web-based personalized feedback interventions can reduce the amount of alcohol consumed in problem drinking college students. This study sought to evaluate whether providing voluntary access to such an intervention would have an impact on drinking. METHODS College students responded to an email inviting them to participate in a short drinking survey. Those meeting criteria for risky drinking (and agreeing to participate in a follow-up) were randomized to an intervention condition where they were offered to participate in a web-based personalized feedback intervention or to a control condition (intervention not offered). Participants were followed-up at six weeks. RESULTS A total of 425 participants were randomized to condition and 68% (n = 290) completed the six-week follow-up. No significant difference in drinking between conditions was observed. CONCLUSIONS Web-based personalized feedback interventions that are offered to students on a voluntary basis may not have a measurable impact on problem drinking. TRIAL REGISTRATION ClinicalTrials.gov: NCT01521078.Support to CAMH for salary of scientists and infrastructure has been provided by the Ontario Ministry of Health and Long Term Care

    Genetic diversity in three invasive clonal aquatic species in New Zealand

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    <p>Abstract</p> <p>Background</p> <p><it>Elodea canadensis, Egeria densa </it>and <it>Lagarosiphon major </it>are dioecious clonal species which are invasive in New Zealand and other regions. Unlike many other invasive species, the genetic variation in New Zealand is very limited. Clonal reproduction is often considered an evolutionary dead end, even though a certain amount of genetic divergence may arise due to somatic mutations. The successful growth and establishment of invasive clonal species may be explained not by adaptability but by pre-existing ecological traits that prove advantageous in the new environment. We studied the genetic diversity and population structure in the North Island of New Zealand using AFLPs and related the findings to the number of introductions and the evolution that has occurred in the introduced area.</p> <p>Results</p> <p>Low levels of genetic diversity were found in all three species and appeared to be due to highly homogeneous founding gene pools. <it>Elodea canadensis </it>was introduced in 1868, and its populations showed more genetic structure than those of the more recently introduced of <it>E. densa </it>(1946) and <it>L. major </it>(1950). <it>Elodea canadensis </it>and <it>L. major</it>, however, had similar phylogeographic patterns, in spite of the difference in time since introduction.</p> <p>Conclusions</p> <p>The presence of a certain level of geographically correlated genetic structure in the absence of sexual reproduction, and in spite of random human dispersal of vegetative propagules, can be reasonably attributed to post-dispersal somatic mutations. Direct evidence of such evolutionary events is, however, still insufficient.</p

    Temporal tensions: EU citizen migrants, asylum seekers and refugees navigating dominant temporalities of work in England

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    This article considers the role of temporality in the differential inclusion of migrants. In order to do this we draw on research which examined the working lives of a diverse group of new migrants in North East England: Eastern European migrants arriving from 2004 and asylum seekers and refugees arriving from 1999. In so doing we emphasise both distinct and shared experiences, related to immigration status but also a range of other dimensions of identity. We specifically consider how dominant temporalities regulate the lives of new migrants through degrees, periods and moments of acceleration/deceleration. The paper illustrates the ways in which dominant temporalities control access and non-access to particular, often precarious forms of work – but also how migrants attempt to navigate such restrictions through their own use and constructions of time. We explore this in relation to three 'phases' of time. Firstly, through experiences of the UK asylum system and work prohibition. Secondly for a broader group of participants we explore the speeding up and slowing down of transitions to and progression within work. Lastly, we consider how participants experience everyday temporal tensions between paid employment and unpaid care. Across these phases we suggest that dominant orderings of time and the narratives which make sense of these, represent non-simultaneous temporalities that do not neatly map onto each other

    High Resolution mid-Infrared Imaging of SN 1987A

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    Using the Thermal-Region Camera and Spectrograph (T-ReCS) attached to the Gemini South 8m telescope, we have detected and resolved 10 micron emission at the position of the inner equatorial ring (ER) of supernova SN 1987A at day 6067. ``Hot spots'' similar to those found in the optical and near-IR are clearly present. The morphology of the 10 micron emission is globally similar to the morphology at other wavelengths from X-rays to radio. The observed mid-IR flux in the region of SN1987A is probably dominated by emission from dust in the ER. We have also detected the ER at 20 micron at a 4 sigma level. Assuming that thermal dust radiation is the origin of the mid-IR emission, we derive a dust temperature of 180^{+20}_{-10} K, and a dust mass of 1.- 8. 10^{-5} Mo for the ER. Our observations also show a weak detection of the central ejecta at 10 micron. We show that previous bolometric flux estimates (through day 2100) were not significantly contaminated by this newly discovered emission from the ER. If we assume that the energy input comes from radioactive decays only, our measurements together with the current theoretical models set a temperature of 90 leq T leq 100 K and a mass range of 10^{-4} - 2. 10^{-3} Mo for the dust in the ejecta. With such dust temperatures the estimated thermal emission is 9(+/-3) 10^{35} erg s^{-1} from the inner ring, and 1.5 (+/-0.5) 10^{36} erg s^{-1} from the ejecta. Finally, using SN 1987A as a template, we discuss the possible role of supernovae as major sources of dust in the Universe.Comment: aastex502, 14 pages, 4 figures; Accepted for publication in ApJ Content changed: new observations, Referee's comments and suggestion

    Customers as decision-makers: strategic environmental assessment in the private sector

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    Despite its diversification and global spread, strategic environmental assessment (SEA) remains limited mainly to activities characterised by well-defined planning processes, typically within the public sector. This article explores the possible application of SEA within certain private-sector contexts where higher-level strategy-making itself is inherently weaker and development is often piecemeal and reactive. The possible adaptation of SEA to the preparation of a strategic document by a particular industrial concern in the UK is examined: this draws attention to the multi-actor nature of development processes within the industry. This leads to the suggestion that SEA in this setting should be thought of as a form of environmental advocacy oriented towards industrial customers, who are understood as sharing a decision-making role in infrastructure development.</p

    Enhancing West Nile Virus Surveillance, United States

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    We provide a method for constructing a county-level West Nile virus risk map to serve as an early warning system for human cases. We also demonstrate that mosquito surveillance is a more accurate predictor of human risk than monitoring dead and infected wild birds
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