369 research outputs found

    COASTAL ALABAMA RECREATIONAL LIVE BAIT STUDY

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    Recreational fishing is major industry and reasonably priced, high quality bait plays an important role in sustaining recreational fishing's popularity. This study provides a summary of Alabama's coastal live bait market including information on previous live bait studies and results of two surveys on the live bait shrimp, bull minnow and other bait markets. Results indicated there were periods of supply shortages, dealer willingness to pay more for shrimp that live longer and a dealers' use of multiple supply sources. Lost income was reported from not having live bait shrimp available for sale at peak demand periods. The economics of shrimp mariculture needs to be examined to determine its feasibility in augmenting the current supply of shrimp to the live bait industry.Resource /Energy Economics and Policy,

    Alpha-decay branching ratios of near-threshold states in 19Ne and the astrophysical rate of 15O(alpha,gamma)19Ne

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    The 15O(alpha,gamma)19Ne reaction is one of two routes for breakout from the hot CNO cycles into the rp process in accreting neutron stars. Its astrophysical rate depends critically on the decay properties of excited states in 19Ne lying just above the 15O + alpha threshold. We have measured the alpha-decay branching ratios for these states using the p(21Ne,t)19Ne reaction at 43 MeV/u. Combining our measurements with previous determinations of the radiative widths of these states, we conclude that no significant breakout from the hot CNO cycle into the rp process in novae is possible via 15O(alpha,gamma)19Ne, assuming current models accurately represent their temperature and density conditions

    Detailed electronic structure studies on superconducting MgB2_2 and related compounds

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    In order to understand the unexpected superconducting behavior of MgB2_2 compound we have made electronic structure calculations for MgB2_2 and closely related systems. Our calculated Debye temperature from the elastic properties indicate that the average phonon frequency is very large in MgB2_2 compared with other superconducting intermetallics and the exceptionally high TcT_c in this material can be explained through BCS mechanism only if phonon softening occurs or the phonon modes are highly anisotropic. We identified a doubly-degenerate quasi-two dimensional key-energy band in the vicinity of EFE_{F} along Γ\Gamma-A direction of BZ which play an important role in deciding the superconducting behavior of this material. Based on this result, we have searched for similar kinds of electronic feature in a series of isoelectronic compounds such as BeB2_2, CaB2_2, SrB2_2, LiBC and MgB2_2C2_2 and found that MgB2_2C2_2 is one potential material from the superconductivity point of view. There are contradictory experimental results regarding the anisotropy in the elastic properties of MgB2_2 ranging from isotropic, moderately anisotropic to highly anisotropic. In order to settle this issue we have calculated the single crystal elastic constants for MgB2_2 by the accurate full-potential method and derived the directional dependent linear compressibility, Young's modulus, shear modulus and relevant elastic properties. We have observed large anisotropy in the elastic properties. Our calculated polarized optical dielectric tensor shows highly anisotropic behavior even though it possesses isotropic transport property. MgB2_2 possesses a mixed bonding character and this has been verified from density of states, charge density and crystal orbital Hamiltonian population analyses

    Computation of protein geometry and its applications: Packing and function prediction

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    This chapter discusses geometric models of biomolecules and geometric constructs, including the union of ball model, the weigthed Voronoi diagram, the weighted Delaunay triangulation, and the alpha shapes. These geometric constructs enable fast and analytical computaton of shapes of biomoleculres (including features such as voids and pockets) and metric properties (such as area and volume). The algorithms of Delaunay triangulation, computation of voids and pockets, as well volume/area computation are also described. In addition, applications in packing analysis of protein structures and protein function prediction are also discussed.Comment: 32 pages, 9 figure

    Single-Particle and Collective Motion for Proton-Rich Nuclei on the Astrophysical rp-Process Path

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    Based on available experimental data, a new set of Nilsson parameters is proposed for proton-rich nuclei with proton or neutron numbers 28≀N≀4028\leq N\leq 40. The resulting single-particle spectra are compared with those from relativistic and non-relativistic mean field theories. Collective excitations in some even--even proton-rich nuclei in the upper pfpf shell are investigated using the Projected Shell Model with the new Nilsson basis. It is found that the regular bands are sharply disturbed by band crossings involving 1g9/21g_{9/2} neutrons and protons. Physical quantities for exploring the nature of the band disturbance and the role of the 1g9/21g_{9/2} single-particle are predicted, which may be tested by new experiments with radioactive beams.Comment: 4 pages, 3 figures, accepted by Phys. Rev. C, Rapid Communicatio

    Accounting for International War: The State of the Discipline

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    In studies of war it is important to observe that the processes leading to so frequent an event as conflict are not necessarily those that lead to so infrequent an event as war. Also, many models fail to recognize that a phenomenon irregularly distributed in time and space, such as war, cannot be explained on the basis of relatively invariant phenomena. Much research on periodicity in the occurrence of war has yielded little result, suggesting that the direction should now be to focus on such variables as diffusion and contagion. Structural variables, such as bipolarity, show contradictory results with some clear inter-century differences. Bipolarity, some results suggest, might have different effects on different social entities. A considerable number of studies analysing dyadic variables show a clear connection between equal capabilities among contending nations and escalation of conflict into war. Finally, research into national attributes often points to strength and geographical location as important variables. In general, the article concludes, there is room for modest optimism, as research into the question of war is no longer moving in non-cumulative circles. Systematic research is producing results and there is even a discernible tendency of convergence, in spite of a great diversity in theoretical orientations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69148/2/10.1177_002234338101800101.pd

    Extent and Causes of Chesapeake Bay Warming

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    Coastal environments such as the Chesapeake Bay have long been impacted by eutrophication stressors resulting from human activities, and these impacts are now being compounded by global warming trends. However, there are few studies documenting long-term estuarine temperature change and the relative contributions of rivers, the atmosphere, and the ocean. In this study, Chesapeake Bay warming, since 1985, is quantified using a combination of cruise observations and model outputs, and the relative contributions to that warming are estimated via numerical sensitivity experiments with a watershed–estuarine modeling system. Throughout the Bay’s main stem, similar warming rates are found at the surface and bottom between the late 1980s and late 2010s (0.02 +/- 0.02C/year, mean +/- 1 standard error), with elevated summer rates (0.04 +/- 0.01C/year) and lower rates of winter warming (0.01 +/- 0.01C/year). Most (~85%) of this estuarine warming is driven by atmospheric effects. The secondary influence of ocean warming increases with proximity to the Bay mouth, where it accounts for more than half of summer warming in bottom waters. Sea level rise has slightly reduced summer warming, and the influence of riverine warming has been limited to the heads of tidal tributaries. Future rates of warming in Chesapeake Bay will depend not only on global atmospheric trends, but also on regional circulation patterns in mid-Atlantic waters, which are currently warming faster than the atmosphere. Supporting model data available at: https://doi.org/10.25773/c774-a36

    A simplified (modified) Duke Activity Status Index (M-DASI) to characterise functional capacity: A secondary analysis of the Measurement of Exercise Tolerance before Surgery (METS) study

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    Background Accurate assessment of functional capacity, a predictor of postoperative morbidity and mortality, is essential to improving surgical planning and outcomes. We assessed if all 12 items of the Duke Activity Status Index (DASI) were equally important in reflecting exercise capacity. Methods In this secondary cross-sectional analysis of the international, multicentre Measurement of Exercise Tolerance before Surgery (METS) study, we assessed cardiopulmonary exercise testing and DASI data from 1455 participants. Multivariable regression analyses were used to revise the DASI model in predicting an anaerobic threshold (AT) >11 ml kg −1 min −1 and peak oxygen consumption (VO 2 peak) >16 ml kg −1 min −1, cut-points that represent a reduced risk of postoperative complications. Results Five questions were identified to have dominance in predicting AT>11 ml kg −1 min −1 and VO 2 peak>16 ml.kg −1min −1. These items were included in the M-DASI-5Q and retained utility in predicting AT>11 ml.kg −1.min −1 (area under the receiver-operating-characteristic [AUROC]-AT: M-DASI-5Q=0.67 vs original 12-question DASI=0.66) and VO 2 peak (AUROC-VO2 peak: M-DASI-5Q 0.73 vs original 12-question DASI 0.71). Conversely, in a sensitivity analysis we removed one potentially sensitive question related to the ability to have sexual relations, and the ability of the remaining four questions (M-DASI-4Q) to predict an adequate functional threshold remained no worse than the original 12-question DASI model. Adding a dynamic component to the M-DASI-4Q by assessing the chronotropic response to exercise improved its ability to discriminate between those with VO 2 peak>16 ml.kg −1.min −1 and VO 2 peak<16 ml.kg −1.min −1. Conclusions The M-DASI provides a simple screening tool for further preoperative evaluation, including with cardiopulmonary exercise testing, to guide perioperative management
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