12,790 research outputs found

    SOUTHERNMOST OCCURRENCE OF THE SUWANNEE COOTER, PSEUDEMYS CONCINNA SUWANNIENSIS (TESTUDINES: EMYDIDAE)

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    The Suwannee Cooter, Pseudemys concinna suwanniensis, the largest member of the speciose turtle family Emydidae, inhabits a small number of rivers that drain into the northeastern Gulf of Mexico along the northwest coast of Florida from just west of Tallahassee to just south of Tampa. The status of this state-protected subspecies in the southernmost of these rivers, the Alafia, is unknown and hence of conservation concern. We provide recent evidence confirming that a reproducing population still exists in this river, and review available specimens and both published and unpublished records documenting the southern limit of distribution. At least within the eastern United States, our observations also extend confirmed knowledge of the geographic occurrence of hatchling turtles overwintering in the nest southward by 285 km

    AN EXPERIMENTAL ECONOMICS APPROACH TO ANALYZING PRICE DISCOVERY IN FORWARD AND SPOT MARKETS

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    Laboratory experiments are used to generate data that facilitate investigation of pricing behavior in forward and spot markets. Results suggest a tendency for prices in a spot market to converge to levels higher than those in a forward market. The difference in these market environments is the supply schedule. Buyers in a spot market are aware that supply is inelastic and become relatively aggressive bidders. Forward markets have a relatively elastic supply schedule and buyers fare better. This may motivate firms to promote forward markets and/or vertically integrate in the procurement of inputs.Experimental economics, Forward market, Price discovery, Spot market, Marketing,

    DIFFERENCES AMONG APPRAISERS IN THE NEW YORK TYPE APPRAISAL PROGRAM

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    The purpose of the New York type appraisal program is to attempt to rate type traits objectively. Approximately 34 traits are included, of which 25 are rated by the appraiser and 9 by the herd manager. This paper reports differences among 18 appraisers, including S professional judges, 7 New York Artificial Breeders\u27 Cooperative fieldmen, and 3 other sire selection personnel all of whom rated 38 cows in a single herd. There were statistically significant differences (P ā‰¤ .05) among appraisers for all traits. Average scores of the professionals were different from those of the fieldmen for all except six traits. Differences among the professionals were also large, as were the differences among the fieldmen. The results suggest that the fieldmen as a group appraised with as much consistency as the group of professional judges

    Seasonal Occurrence of Epifauna on Test Panels In Hampton Roads, Virginia

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    A two-year study was made on settling patterns of some marine epifaunal frmcrtebrales in the port of Hampton Roads, Virginia. Asbestos fiber test panels, submerged to a depth of 5 m from a pier at the Norfolk Navy Base, wf:re used as substrates. The fouling assemblage consisted of species characteristic of the temperate North American Atlantic coast. Over half of the 41 species identified were either coelenterates or arthropods, although sponges, tttrbellarians, ectoprocts, J\u3eolychaetes, mollusks, and ascidians were present as well. Four species, Aselomaris michaeli, Clytia edwardsi, Obelia bicuspidata and 0. commissuralis, all hydroids, represent new distributional records for Virginia. The large annual range of water temperature results in distinct seasonal patterns of settlement. Attachment was heaviest froni May to November and lightest fiĀ·om January to March. Barnacles (Balanus improvisus) were prevalent during spring and autumn, while ascidians (Molgula manhattensis, Botryllus schlosseri) and serpulids (Hydroides hexagona) were predominant in summer. Only Balanus improvisus occurred on the panels throughout the year

    Correlation between fracture surface morphology and toughness in Zr-based bulk metallic glasses

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    Fracture surfaces of Zr-based bulk metallic glasses of various compositions tested in the as-cast and annealed conditions were analyzed using scanning electron microscopy. The tougher samples have shown highly jagged patterns at the beginning stage of crack propagation, and the length and roughness of this jagged pattern correlate well with the measured fracture toughness values. These jagged patterns, the main source of energy dissipation in the sample, are attributed to the formation of shear bands inside the sample. This observation provides strong evidence of significant ā€œplastic zoneā€ screening at the crack tip

    Hands-on Gravitational Wave Astronomy: Extracting astrophysical information from simulated signals

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    In this paper we introduce a hands-on activity in which introductory astronomy students act as gravitational wave astronomers by extracting information from simulated gravitational wave signals. The process mimics the way true gravitational wave analysis will be handled by using plots of a pure gravitational wave signal. The students directly measure the properties of the simulated signal, and use these measurements to evaluate standard formulae for astrophysical source parameters. An exercise based on the discussion in this paper has been written and made publicly available online for use in introductory laboratory courses.Comment: 5 pages, 4 figures; submitted to Am. J. Phy

    DIFFERENCES AMONG APPRAISERS IN THE NEW YORK TYPE APPRAISAL PROGRAM

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    The purpose of the New York type appraisal program is to attempt to rate type traits objectively. Approximately 34 traits are included, of which 25 are rated by the appraiser and 9 by the herd manager. This paper reports differences among 18 appraisers, including S professional judges, 7 New York Artificial Breeders\u27 Cooperative fieldmen, and 3 other sire selection personnel all of whom rated 38 cows in a single herd. There were statistically significant differences (P ā‰¤ .05) among appraisers for all traits. Average scores of the professionals were different from those of the fieldmen for all except six traits. Differences among the professionals were also large, as were the differences among the fieldmen. The results suggest that the fieldmen as a group appraised with as much consistency as the group of professional judges

    Bowen ratio estimates of evapotranspiration for stands on the Virgin River in Southern Nevada

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    A Bowen ratio energy balance was conducted over a Tamarix ramosissima (saltcedar) stand growing in a riparian corridor along the Virgin River in southern Nevada. Measurements in two separate years were compared and contrasted on the basis of changes in growing conditions. In 1994, a drought year, record high temperatures, dry winds, and a falling water table caused partial wilt of outer smaller twigs in the canopy of many trees in the stand around the Bowen tower. Subsequently, evapotranspiration (ET) estimates declined dramatically over a 60ā€day period (11 mm dāˆ’1 todāˆ’1). In 1995, the Virgin River at the Bowen tower area changed its course, hydrologically isolating the Tamarix stand in the vicinity of the tower. In 1996, a 25% canopy loss was visually estimated for the Tamarix growing in the area of the tower. Higher soil temperatures relative to air temperatures were recorded in 1996 in response to this loss in canopy. With a more open canopy, thermally induced turbulence was observed in 1996. On day 160 of 1996, a 28Ā°C rise over a 9ā€hour period was correlated with increased wind speeds of greater than 4 m sāˆ’1. Subsequently, higher ET estimates were made in 1996 compared to 1994 (145 cm versus 75 cm). However, the energy balance was dominated by advection in 1996, with latent energy flux exceeding net radiation 65% of the measurement days compared to only 11% in 1994. We believe this advection was on a scale of the floodplain (hundreds of meters) as opposed to regional advection, since the majority of wind (90%) was in a Nā€“S direction along the course of the river, and that a more open canopy allowed the horizontal transfer of energy into the Tamarix stand at the Bowen tower. Our results suggest that Tamarix has the potential to be both a low water user and a high water user, depending on moisture availability, canopy development, and atmospheric demand, and that advection can dominate energy balances and ET in aridland riparian zones such as the Virgin River

    Potential flow theory and operation guide for the panel code PMARC

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    The theoretical basis for PMARC, a low-order potential-flow panel code for modeling complex three-dimensional geometries, is outlined. Several of the advanced features currently included in the code, such as internal flow modeling, a simple jet model, and a time-stepping wake model, are discussed in some detail. The code is written using adjustable size arrays so that it can be easily redimensioned for the size problem being solved and the computer hardware being used. An overview of the program input is presented, with a detailed description of the input available in the appendices. Finally, PMARC results for a generic wing/body configuration are compared with experimental data to demonstrate the accuracy of the code. The input file for this test case is given in the appendices
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