4,779 research outputs found

    Primitive divisors of elliptic divisibility sequences

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    Silverman proved the analogue of Zsigmondy's Theorem for elliptic divisibility sequences. For elliptic curves in global minimal form, it seems likely this result is true in a uniform manner. We present such a result for certain infinite families of curves and points. Our methods allow the first explicit examples of the elliptic Zsigmondy Theorem to be exhibited. As an application, we show that every term beyond the fourth of the Somos-4 sequence has a primitive divisor

    Comparing Bird Population Trends in the Badlands and Prairies Using BBS and IMBCR Data

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    We compared the direction and precision of trend estimates of bird species in the Badlands and Prairie Bird Conservation Region (BCR 17) from 2009-2015 using Breeding Bird Survey (BBS) and Integrated Monitoring in Bird Conservation Regions (IMBCR) data. We used Bayesian modeling estimates provided by the BBS and newly developed Bayesian estimates of IMBCR data. Trend estimates often differed between the two data sets and estimates of precision were generally smaller for IMBCR than for BBS data. In addition, because the BBS estimates do not correct for detection probability, the BBS estimates measure the trend on an index rather than the detection corrected abundance. If the relationship between the BBS index and true abundance is not linear and 1:1, the interpretation of the BBS trend is unclear. Finally, because BBS counts are conducted along roads, species that are attracted to or avoid roads may be over or under counted, respectively. BBS trends can be helpful for examining long-term trends (greater than 20 years) in bird abundance across large regions but only IMBCR trends provide sufficient precision to examine trends at shorter time intervals. IMBCR trends, therefore, are more useful for identifying current factors influencing bird population trends

    Telecommunications Act of 1996: 704 of the Act and Protections Afforded the Telecommunications Provider in the Facilities Sitting Context, The

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    The Telecommunications Act of 1996, signed into law by President Clinton in February, addresses, among many other important subjects, some of the technical problems that have arisen from the increasing popularity of mobile communications. This article will provide an overview of the Act and will focus specifically on the protections afforded a telecommunications provider in § 704 of the Act

    Telecommunications Act of 1996: 704 of the Act and Protections Afforded the Telecommunications Provider in the Facilities Sitting Context, The

    Get PDF
    The Telecommunications Act of 1996, signed into law by President Clinton in February, addresses, among many other important subjects, some of the technical problems that have arisen from the increasing popularity of mobile communications. This article will provide an overview of the Act and will focus specifically on the protections afforded a telecommunications provider in § 704 of the Act

    The effect of consumer attitudes on design for product longevity: the case of the fashion industry

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    Product longevity is a key aspect of sustainability and encouraging consumers to prolong the lifetime of products therefore has a part to play in minimising environmental sustainability impacts. The production, distribution and disposal phases of the clothing life cycle all create environmental impacts, but extending garments’ active life via design, maintenance and re-use of clothing is the most effective method of reducing the negative effects of the clothing industry on the environment. The study took an exploratory approach using mixed qualitative research methods to investigate consumer perspectives on clothing longevity and explore everyday processes and practices of clothing use, e.g. purchase, wear, care, maintenance, repair, re-use and disposal. The research findings showed that numerous factors affect consumers’ perspectives of clothing longevity during the purchase, usage and disposal stages of the clothing lifecycle. The conclusion addresses how these factors can influence product design practice in the fashion industry

    Alien invasions and livelihoods: Economic benefits of invasive Australian Red Claw crayfish in Jamaica

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    Invasive species have caused widespread economic and environmental disruption, which have been widely studied. However, their potential benefits have received much less attention. If invasive species contribute to livelihoods, their eradication may negatively impact wellbeing. Failing to value these benefits may lead to an undervaluation of invaded ecosystems. We assess the potential economic benefits of an invasive species within an artisanal fishery in Jamaica. We monitored catches over 259 fisherman-days, and conducted 45 semi-structured interviews, with 76 fishermen. We show that the invasive Australian Red Claw crayfish (Cherax quadricarinatus) is an important source of income for fishermen within the Black River Lower Morass of Jamaica and supplement incomes during periods when native shrimp (Macrobrachium spp.) catches decline. We also show that full-time fishermen and those who have no alternative occupations expend the greatest fishing effort. We use the intra-annual variation of fishermen's harvest effort between seasons (when catch per unit effort changes) as a proxy for dependence. Using this measure, we found that the least wealthy appear to be the most dependent on fishing, and consequently benefit the most from the invasive crayfish. Our results demonstrate the importance of considering the potential benefits of invasive species within integrated landscape management
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