6,897 research outputs found

    Developing, Implementing and Evaluating Policies to Support Fisheries Co-management

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    The aim of this document is to bring together a number of the lessons relating to the development, implementation and evaluation of policies to support co-management that have emerged from projects undertaken through the DFID Fisheries Management Science Programme (FMSP) and elsewhere. It is beyond the scope of this document to provide a comprehensive analysis or guide. It seeks to highlight some experiences and some areas that need to be considered by policy makers when attempting to develop sustainably co-managed fisheries. This document is targeted to fisheries policy makers, and decision-makers concerned with the fisheries sector

    Co-management: A Synthesis of the Lessons Learned from the DFID Fisheries Management Science Programme

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    For the last eleven years, the UK Department for International Development (DfID) have been funding research projects to support the sustainable management of fisheries resources (both inland and marine) in developing countries through the Fisheries Management Science Programme (FMSP). A number of these projects that have been commissioned in this time have examined fisheries co-management. While these projects have, for the most part, been implemented separately, the FMSP has provided an opportunity to synthesise and draw together some of the information generated by these projects. We feel that there is value in distilling some of the important lessons and describing some of the useful tools and examples and making these available through a single, accessible resource. The wealth of information generated means that it is impossible to cover everything in detail but it is hoped that this synthesis will at least provide an overview of the co-management process together with some useful information relating to implementing co-management in a developing country context and links to the more detailed re-sources available, in particular on information systems for co-managed fisheries, participatory fish stock assessment (ParFish) and adaptive learning that have, in particular, been drawn upon for this synthesis. This synthesis is aimed at anyone interested in fisheries management in a developing country context

    The affinities of Proterochampsa barrioneuvoi Reig

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    Proterochampsa barrioneuvoi Reig is re-examined and is confirmed as a proterosuchian thecodont. None of the features previously thought to ally it to the Crocodilia are solely characteristic of that group. On the other hand it is not a phytosaur nor phytosaur ancestor, only showing one real trend towards these animals in the rearward migration of the internal and external nares. Proterochampsa and its relatives Chanaresuchus, Gualosuchus and Cerritosaurus are too late in time to be phytosaur ancestors. They are grouped together in the Proterochampsidae, a family within the Proterosuchia.CSIR; Anderson-Capelli fund of the University of the Witwatersran

    The skeleton of the Triassic anomodont Kannemeyeria wilsoni Broom

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    The general structure of the post-cranial skeleton of many Triassic anomodonts is now well known, but in Africa that of the stratigraphically important Lower Triassic (? Scythian) genus Kannemeyeria is known only from dissociated elements. A brief description is given for the first time of an almost complete skeleton ascribed to this genus. The environment of deposition is described briefly. The locality of the type species of the genus is also noted .CSIR; University of the Witwatersran

    Quantitative modeling of \textit{in situ} x-ray reflectivity during organic molecule thin film growth

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    Synchrotron-based x-ray reflectivity is increasingly employed as an \textit{in situ} probe of surface morphology during thin film growth, but complete interpretation of the results requires modeling the growth process. Many models have been developed and employed for this purpose, yet no detailed, comparative studies of their scope and accuracy exists in the literature. Using experimental data obtained from hyperthermal deposition of pentane and diindenoperylene (DIP) on SiO2_2, we compare and contrast three such models, both with each other and with detailed characterization of the surface morphology using ex-situ atomic force microscopy (AFM). These two systems each exhibit particular phenomena of broader interest: pentacene/SiO2_2 exhibits a rapid transition from rough to smooth growth. DIP/SiO2_2, under the conditions employed here, exhibits growth rate acceleration due to a different sticking probability between the substrate and film. In general, \textit{independent of which model is used}, we find good agreement between the surface morphology obtained from fits to the \insitu x-ray data with the actual morphology at early times. This agreement deteriorates at later time, once the root-mean squared (rms) film roughness exceeds about 1 ML. A second observation is that, because layer coverages are under-determined by the evolution of a single point on the reflectivity curve, we find that the best fits to reflectivity data --- corresponding to the lowest values of χν2\chi_\nu^2 --- do not necessarily yield the best agreement between simulated and measured surface morphologies. Instead, it appears critical that the model reproduce all local extrema in the data. In addition to showing that layer morphologies can be extracted from a minimal set of data, the methodology established here provides a basis for improving models of multilayer growth by comparison to real systems.Comment: 34 pages (double-spaced, including figures and references), 10 figures, 3 appendice

    Linear oscillations of a compressible hemispherical bubble on a solid substrate

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    The linear natural and forced oscillations of a hemispherical bubble on a solid substrate are under theoretical consideration. The contact line dynamics is taken into account with the Hocking condition, which eventually leads to interaction of the shape and volume oscillations. Resonant phenomena, mostly pronounced for the bubble with the fixed contact line or with the fixed contact angle, are found out. The limiting case of weakly compressible bubble is studied. The general criterion identifying whether the compressibility of a bubble can be neglected is obtained.Comment: new slightly extended version with some minor changes, added journal reference and DOI information; 12 pages, 8 figures, published in Physics of Fluid

    Oral Tissue Responses to Travel in Space

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    The oral cavity functions in taste, mastication, solubilization and digestion of nutrients, as well as in respiration and speech, and participates in innate and adaptive immunity. Saliva creates and regulates the environment of the oral cavity, and changes in its composition and rate of secretion have significant effects on oral tissues as well as on systemic health. The effects of microgravity on the salivary glands, mandible and teeth were studied in mice flown on US space shuttle STS-131 and STS-135 missions, and the Russian Bion-M1 biosatellite. Significant changes in morphology and secretory protein expression occurred in parotid glands; submandibular glands were affected only on the 30-day Bion-M1 mission, indicating tissue specificity of the effects due to changes in gravity which may be similar to those taking place in humans. Changes also occurred in mandibular bone and incisor teeth. Collection of saliva is a non-invasive procedure for assessing physiological status and diagnosis of several disorders and provides a simple method for monitoring astronaut health during extended spaceflight

    Mass Models for Spiral Galaxies from 2-D Velocity Maps

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    We model the mass distributions of 40 high surface brightness spiral galaxies inside their optical radii, deriving parameters of mass models by matching the predicted velocities to observed velocity maps. We use constant mass-to-light disk and bulge models, and we have tried fits with no halo and with three different halo density profiles. The data require a halo in most, but not all, cases, while in others the best fit occurs with negligible mass in the luminous component, which we regard as unphysical. All three adopted halo profiles lead to fits of about the same quality, and our data therefore do not constrain the functional form of the halo profile. The halo parameters display large degeneracies for two of the three adopted halo functions, but the separate luminous and dark masses are better constrained. However, the fitted disk and halo masses vary substantially between the adopted halo models, indicating that even high quality 2-D optical velocity maps do not provide significant constraints on the dark matter content of a galaxy. We demonstrate that data from longslit observations are likely to provide still weaker constraints. We conclude that additional information is needed in order to constrain the separate disk and halo masses in a galaxy.Comment: 41 pages, 13 figures, accepted for publication in A

    Generalized minority games with adaptive trend-followers and contrarians

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    We introduce a simple extension of the minority game in which the market rewards contrarian (resp. trend-following) strategies when it is far from (resp. close to) efficiency. The model displays a smooth crossover from a regime where contrarians dominate to one where trend-followers dominate. In the intermediate phase, the stationary state is characterized by non-Gaussian features as well as by the formation of sustained trends and bubbles.Comment: 4 pages, 6 figure
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