2,356 research outputs found

    Optimization of plasmon–plasmon coupling in photorefractive layered media

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    In this paper we study grating-induced plasmon–plasmon coupling in photorefractive layered media using a weakcoupling approximation. The method used is applicable to general layered structures that support both plasmonic and optical modes, such as photorefractive liquid crystal cells. The approximate equations are accurate when compared to S matrix approaches and capture the plasmon propagation at the surface of the device along with the optical modes guided by the layered geometry underneath. Analysis of the resulting model provides insight into the effect of the control parameters in this device and the means to optimize the diffraction efficiency. For example, by considering the case in which the plasmon is spectrally separated from the guided modes it is possible to determine the optimum gold thickness and grating strength required to obtain the strongest possible diffraction

    Developing rigor in qualitative research: problems and opportunities within sport and exercise psychology

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    Qualitative research has grown within sport and exercise psychology and is now widely conducted. The purpose of this review is to discuss three commonly used ways to demonstrate rigor when conducting or judging qualitative research in sport and exercise psychology. These are the method of member checking, the method of inter-rater reliability, and the notion of universal criteria. Problems with each method are first highlighted. Member checking and inter-rater reliability are shown to be ineffective for verification, trustworthiness, or reliability purposes. Next, universal criteria within the context of Tracy’s, heavily drawn on paper within sport and exercise psychology is problematized. Throughout the discussion of each method and universal criteria more suitable possibilities for conducting rigorous qualitative research are offered. The paper concludes that to support high-quality qualitative research, scholars – including journal editors and reviewers – need to change how rigor is developed and judged, rather than perpetuate the problems with how it has been commonly evaluated in the past. Recommendations for developing rigor when conducting and/or judging qualitative research within sport and exercise psychology are also offered

    Summer range fidelity of radio-collared caribou in Alaska's Central Arctic Herd

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    Sixty-four adult (2 + years) female caribou (Rangifer tarandus grand), radio-collared in April or May 1975 - 82, were relocated during the following June and/or July within the summer range of the Central Arctic Herd (CAH). Relocations made during the following three summers were used to assess range fidelity. Cumulative relocations of radio-collared females in the Central Arctic region were equivalent to 91% of the projected availability based on transmitter life. A chronological analysis indicates that 98%, 91%, and 82% of radio-collared females were found there one, two, and three years later; most of the progressively lower relocation success is probably attributable to transitter malfunctions rather than emigration. These observations suggest that summer range fidelity of adult females in the CAH is at least 90%, and may approach 100%

    Emotion: Appraisal-coping model for the "Cascades" problem

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    Modelling emotion has become a challenge nowadays. Therefore, several models have been produced in order to express human emotional activity. However, only a few of them are currently able to express the close relationship existing between emotion and cognition. An appraisal-coping model is presented here, with the aim to simulate the emotional impact caused by the evaluation of a particular situation (appraisal), along with the consequent cognitive reaction intended to face the situation (coping). This model is applied to the "Cascades" problem, a small arithmetical exercise designed for ten-year-old pupils. The goal is to create a model corresponding to a child's behaviour when solving the problem using his own strategies.Comment: 6 page

    Current-voltage characteristic of parallel-plane ionization chamber with inhomogeneous ionization

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    The balances of particles and charges in the volume of parallel-plane ionization chamber are considered. Differential equations describing the distribution of current densities in the chamber volume are obtained. As a result of the differential equations solution an analytical form of the current-voltage characteristic of parallel-plane ionization chamber with inhomogeneous ionization in the volume is got.Comment: 8 pages, 4 figure

    Arctic Ice Islands

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    Contains an account of the discovery of two groups of "ice islands" evidently originating on the north coast of Ellesmere Island. Their size, shape and surface structure, as well as tracking the drift of the large ice islands by planes and radar, are discussed by Major Koenig (from U.S.A.F. "Ptarmigan" and other flights), and by Squadron-Leader Greenaway (from Canadian flights and air photographs). Extensive documentation is presented (by Miss Dunbar) of 19th-20th century explorers' references to, and observations of such "islands". The probability of their origin from shelf ice and the character of the ice shelf of Northern Ellesmere is presented (by Mr. Hattersley-Smith). Special consideration is given to three very large islands (identified as T1 T2 T3), their discovery, positions and movement, description, seasonal changes, etc.; with additional data on smaller "islands," arranged according to the areas of their presence. From the air the "floating islands" are easily distinguishable from pack ice by their large size, homogenous appearance, very regular, characteristically patterned surface, and a fixed shape suggesting great thickness and hardness. Bibliography (about 40 items)

    Abundance and movements of caribou in the oilfield complex near Prudhoe Bay, Alaska

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    We examined the distribution and movements of 141 radiocollared female caribou (Rangifer tarandus granti) of the Central Arctic Herd during summer, 1980-1993. Numbers of caribou locations within each of 5 quadrats along the arctic coast were totalled separately for days during which insects were active and inactive, and numbers of east-west and west-east crossings of each quadrat mid-line were determined from sequential observations. Both abundance and lateral movements of radiocollared females in the quadrat encompassing the intensively-developed Prudhoe Bay oilfield complex were significantly lower than in other quadrats (P < 0.001 and P < 0.00001, respectively). Avoidance of, and fewer movements within, the complex by female caribou are ostensibly in response to the dense network of production and support facilities, roads, above-ground pipelines, and the associated vehicular and human activity. Impaired access to this area constitutes a functional loss of habitat

    Using familial information for variant filtering in high-throughput sequencing studies

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    High-throughput sequencing studies (HTS) have been highly successful in identifying the genetic causes of human disease, particularly those following Mendelian inheritance. Many HTS studies to date have been performed without utilizing available family relationships between samples. Here, we discuss the many merits and occasional pitfalls of using identity by descent information in conjunction with HTS studies. These methods are not only applicable to family studies but are also useful in cohorts of apparently unrelated, 'sporadic' cases and small families underpowered for linkage and allow inference of relationships between individuals. Incorporating familial/pedigree information not only provides powerful filtering options for the extensive variant lists that are usually produced by HTS but also allows valuable quality control checks, insights into the genetic model and the genotypic status of individuals of interest. In particular, these methods are valuable for challenging discovery scenarios in HTS analysis, such as in the study of populations poorly represented in variant databases typically used for filtering, and in the case of poor-quality HTS data

    Energy Primer. Online Textbook based on Chapter 1 of the Global Energy Assessment (GEA)

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    This Energy Primer aims at a basic-level introduction to fundamental concepts and data that help to understand energy systems holistically and to provide a common conceptual and terminological framework before examining in greater detail the various aspects of energy systems be them technological, economic, or environmental. As such the text aims to provide a basic introductory reader suitable for the core content of any introductory-level energy class or as framing complement to more specialized energy classes. Customary energy texts usually focus on describing current energy industries through a supply side perspective, which this Energy Primer does not intend to duplicate. (In depth treatments of energy supply and industry aspects of energy systems are provided in Chapters 11 to 15 of the Global Energy Assessment, all available online

    Kerosene subsidies for household lighting in India: what are the impacts?

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    Kerosene subsidy reform is a key policy concern in India and other developing countries. As kerosene is widely used for lighting in India, any price change will likely have considerable public welfare impacts on the large fraction of the poor who do not have access to reliable electricity supply for lighting. In this study, we assess historic kerosene use for residential lighting across population groups separated by urban/rural, expenditure, and electricity service levels using data from India. Consumption trends are used to inform a service demand model and evaluate how changes in fuel price, electricity connection, and supply reliability influence environmental, health and economic outcomes. We find that users relying on kerosene for supplemental lighting—in combination ('stacked') with electricity—accounted for 64% of residential kerosene consumed for lighting in 2005. Tested scenarios that addressed service needs of supplemental users had the greatest welfare benefits, especially in the future. Scenarios reducing PM2.5 emissions from kerosene lighting can avert between 50 and 300 thousand disability adjusted life years relative to a baseline scenario in 2030. Lighting kerosene is highly price sensitive, resulting in a drop in demand of 97% in a scenario in which current subsidies are phased out by 2030. Deadweight loss of the subsidy in 2005 is estimated at $200–950 million, with three quarters attributable to supplemental kerosene lighting. Support for cleaner lighting technologies not reliant on fossil fuel subsidies would appear to be 'no regrets' or 'co-benefits' options for India, and could be implemented in parallel with subsidy removal
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