1,063 research outputs found

    Legal Research: Techniques and Ideas

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    This paper was prepared for the conference of New Zealand University Law Teachers held at Massey University in November 1977. Though the authors here make no special claims originality or great insight, the many ideas developed, particularly when taken together with Professor Campbell's trenchant piece on legal writing and John Thomas' more recent article on legal education (both reprinted in this volume), which stresses the relationship between teaching and research, will be of value to the increasing numbers of lawyers engaged in research

    La economía política institucional del desarrollo local: dos cuentos de turismo en Brasil

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    There is growing recognition within local and regional studies regarding the importance of institutions. A ‘soft institutionalism’ predominates, which is criticised here for leaving out the explicit role of the State and for having a bias towards synergies and positive externalities. We seek to contribute to an institutional political economic theory of local development. We bring together social and political conceptions of ‘old institutional economics’ and evolutionary economics, and the State is explicitly brought back into the analysis. The construction of new institutions is explored as a path dependent process in which institutions (re)shape the development path of an area in a particular direction. Using different kinds of power resources, different social groups struggle for control. We use the framework to analyze the divergent stories of two cases of local development in Brazil based on tourism. Prainha do Canto Verde developed community-based tourism, while in Jericoacoara local development culminated in mass tourism

    Recent Developments: Maryland General Assembly Update

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    A Full-Potential-Linearized-Augmented-Plane-Wave Electronic Structure Study of delta-Plutonium and the (001) Surface

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    The electronic and geometric properties of bulk fcc delta-plutonium and the quantum size effects in the surface energies and the work functions of the (001) ultra thin films (UTF) up to 7 layers have been investigated with periodic density functional theory calculations within the full-potential linearized augmented-plane wave (FP-LAPW) approach as implemented in the WIEN2k package. Our calculated equilibrium atomic volume of 178.3 a.u.^3 and bulk modulus of 24.9 GPa at the fully relativistic level of theory, i.e. spin-polarization and spin-orbit coupling included, are in good agreement with the experimental values of 168.2 a.u.^3 and 25 GPa (593 K), respectively. The calculated equilibrium lattice constants at different levels of approximation are used in the surface properties calculations for the thin films. The surface energy is found to be rapidly converged with the semi-infinite surface energy predicted to be 0.692eV at the fully-relativistic level.Comment: 27 pages,8 figure

    Origin of molecular oxygen in Comet 67P/Churyumov-Gerasimenko

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    Molecular oxygen has been detected in the coma of comet 67P/Churyumov-Gerasimenko with abundances in the 1-10% range by the ROSINA-DFMS instrument on board the Rosetta spacecraft. Here we find that the radiolysis of icy grains in low-density environments such as the presolar cloud may induce the production of large amounts of molecular oxygen. We also show that molecular oxygen can be efficiently trapped in clathrates formed in the protosolar nebula, and that its incorporation as crystalline ice is highly implausible because this would imply much larger abundances of Ar and N2 than those observed in the coma. Assuming that radiolysis has been the only O2 production mechanism at work, we conclude that the formation of comet 67P/Churyumov-Gerasimenko is possible in a dense and early protosolar nebula in the framework of two extreme scenarios: (1) agglomeration from pristine amorphous icy grains/particles formed in ISM and (2) agglomeration from clathrates that formed during the disk's cooling. The former scenario is found consistent with the strong correlation between O2 and H2O observed in 67P/C-G's coma while the latter scenario requires that clathrates formed from ISM icy grains that crystallized when entering the protosolar nebula.Comment: The Astrophysical Journal Letters, in pres

    Atomic density and temperature distributions in magneto-optical traps

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    A theoretical investigation into density, pressure, and temperature distributions in magneto-optical traps is presented. After a brief overview of the forces that arise from reradiation and absorption, a condition that the absorptive force be conservative is used to show that, if the temperature is uniform throughout the trap, any. density solutions to the force equations will not be physical. Further, consistent density solutions are unlikely to exist at all. In contrast, with a varying temperature reasonable solutions are demonstrated, with some restrictions. Doppler forces involved in ring-shaped trap structures are used to calculate orbit radii in racetrack geometry traps, and corrections to the present discrepancy between theoretical and experimental studies are discussed in the context of reradiation and diffusion

    Silyl-heparin bonding improves the patency and in vivo thromboresistance of carbon-coated polytetrafluoroethylene vascular grafts

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    AbstractObjectivesOur purpose was to improve the performance of carbon-coated expanded polytetrafluoroethylene vascular grafts by bonding the grafts with silyl-heparin, a biologically active heparin analog, using polyethylene glycol as a cross-linking agent.Material and methodSilyl-heparin–bonded carbon-coated expanded polytetrafluoroethylene vascular grafts (Bard Peripheral Vascular, Tempe, Ariz), were evaluated for patency and platelet deposition 2 hours, 7 days, and 30 days after graft implantation in a canine bilateral aortoiliac artery model. Platelet deposition was determined by injection of autologous, 111Indium-radiolabeled platelets, followed by a 2-hour circulation period prior to graft explantation. Histologic studies were performed on a 2-mm longitudinal strip of each graft (7-day and 30-day groups). Heparin activity of the explanted silyl-heparin grafts was determined by using an antithrombin-III based thrombin binding assay.ResultsOverall chronic graft patency (7-day and 30-day groups) was 100% for the silyl-heparin bonded (16/16) grafts versus 68.75% for control (11/16) grafts (P = .043). Acute 2-hour graft patency was 100% for the silyl-heparin bonded (6/6) grafts versus 83.3% for control (5/6) grafts. Radiolabeled platelet deposition studies revealed a significantly lower amount of platelets deposited on the silyl-heparin grafts as compared with control grafts in the 30-day group (13.8 ± 7.18 vs 28.4 ± 9.73, CPM per cm2 per million platelets, mean ± SD, P = .0451, Wilcoxon rank sum test). In the 2-hour group of dogs, a trend towards a lower deposition of platelets on the silyl-heparin grafts was observed. There was no significant difference in platelet deposition between the two grafts in the 7-day group. Histologic studies revealed a significant reduction in intraluminal graft thrombus present on the silyl-heparin grafts as compared with control grafts in the 30-day group of animals. In contrast, there was no difference in amount of graft thrombus present on both graft types in the 7-day group of dogs. Pre-implant heparin activity on the silyl-heparin bonded grafts was 2.0 IU/cm2 (international units[IU]/cm2). Heparin activity remained present on the silyl-heparin grafts after explantation at all 3 time points (2 hours: above upper limit of assay, upper limit = 0.57, n = 6; 7 days: 0.106 ± 0.015, n = 5; 30 days: 0.007 ± 0.001, n = 5; mean ± SD, IU/cm2).ConclusionSilyl-heparin bonding onto carbon-coated expanded polytetrafluoroethylene vascular grafts resulted in (1) improved graft patency, (2) increased in vivo graft thromboresistance, and (3) a significant reduction in intraluminal graft thrombus. This graft may prove to be useful in the clinical setting.AbstractClinical relevanceExpanded polytetrafluoroethylene (ePTFE) remains the most commonly used prosthetic graft material in infrainguinal arterial reconstructions. Reported long-term patency rates of ePTFE bypass grafts are inferior to those observed with autogenous vein. Modification of the luminal surface of ePTFE bypass grafts may prevent early graft failure and ultimately improve long-term graft performance. Silyl-heparin is a biologically active heparin analog that is readily adsorbed onto hydrophobic surfaces while retaining its anticoagulant properties. Silyl-heparin bonding onto carbon-coated ePTFE grafts improves the patency and in vivo thromboresistance and results in a decrease in intraluminal graft thrombus. This graft may be useful in the clinical setting
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