21,563 research outputs found

    Sub-committee Approval Voting and Generalised Justified Representation Axioms

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    Social choice is replete with various settings including single-winner voting, multi-winner voting, probabilistic voting, multiple referenda, and public decision making. We study a general model of social choice called Sub-Committee Voting (SCV) that simultaneously generalizes these settings. We then focus on sub-committee voting with approvals and propose extensions of the justified representation axioms that have been considered for proportional representation in approval-based committee voting. We study the properties and relations of these axioms. For each of the axioms, we analyse whether a representative committee exists and also examine the complexity of computing and verifying such a committee

    Pentatomidae of Arkansas

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    A total of 30 genera and 53 species and subspecies of Pentatomidae are reported as occurring or possibly occurring in Arkansas. Fifty species and subspecies contained in 29 genera were collected or recorded from previously collected material. Based on distributional records in the literature, three additional species and one genus are listed as probably occurring in Arkansas. County and seasonal records are reported for each taxon

    The story of a small trout fishery

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    This article relates the experience of creating and developing a fishery in southern England. The fishery was made from a small stream which dries up from time to time, and marks the boundary between a Sussex farm and a large coniferous forest. The preparation of the site and creation of the impoundment are described, and early experiences outlined. The fishery was expanded in later years, as a result of its popularity, and records of its use by anglers are illustrated. The performance of the fishery is measured in terms of "good fish" (more than 675 g) taken, and their number has increased from 81 in 1984 to 226 in 1991. The aquatic plants, invertebrates, and birds of the fishery are discussed, as are the natural predators of the fish

    Relative Abundance, Seasonal Distribution and Taxonomy of Sphingidae of Northeast Arkansas

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    A total of 38 species of sphingids, with keys and descriptions, are reported from Northeast Arkansas. Graphs and tables are presented to show relative abundance and seasonal distribution. Drawings of genitalia, fore tibiae, and forewings, as well as photographs of species in the key are included

    Soil Traversing Arthropod Populations as Sampled by Pitfall Traps in Sunflower and Three Adjacent Habitats in Northeast Arkansas

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    Soil traversing arthropod populations were sampled by pitfall traps in sunflower (Helianthus spp.) and three adjacent habitats during the months of July, August and September of 1980 and May, June, July and August of 1981. In1980, four varieties of sunflower (Ellar, Hybrid 670, 891 and S-345) were planted. A single variety of sunflower (Ellar) was planted in1981. The three adjacent habitats in both 1980 and 1981 were a pine stand, grass border and fence row. Of 1,748 specimens collected in 1980, 17 orders and 48 families were represented. Four orders comprised 78% of the total catch: Hymenoptera (45%), Acari (17%), Collembola(11%) and Coleoptera (5%). In 1981, 20 orders and 64 families were represented in a total of 26,693 trapped specimens. Four orders composed 88% of the total catch: Collembola (57%), Acari (14%), Hymenoptera (11%) and Homoptera (6%). Family composition and seasonal occurrence are discussed and compared for habitats sampled. Weather data are presented and discussed in relation to arthropod activit

    Apollo oxygen tank stratification analysis, volume 2

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    An analysis of flight performance of the Apollo 15 cryogenic oxygen tanks was conducted with the variable grid stratification math model developed earlier in the program. Flight conditions investigated were the CMP-EVA and one passive thermal control period which exhibited heater temperature characteristics not previously observed. Heater temperatures for these periods were simulated with the math model using flight acceleration data. Simulation results (heater temperature and tank pressure) compared favorably with the Apollo 15 flight data, and it was concluded that tank performance was nominal. Math model modifications were also made to improve the simulation accuracy. The modifications included the addition of the effects of the tank wall thermal mass and an improved system flow distribution model. The modifications improved the accuracy of simulated pressure response based on comparisons with flight data
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