4,217 research outputs found

    Locally managed marine areas: implications for socio - economic impacts in Kadavu, Fiji

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    Marine protected areas (MPAs) are a widely used marine conservation tool designed to preserve marine biodiversity and improve fisheries management. Although the environmental benefits of MPAs are well established, evaluating the social and economic impacts of MPAs is challenging. In this paper we quantitatively identify the economic and social differences between communities based on whether or not the community has a tabu area in their local fishing ground. This is an area permanently closed to fishing within a locally managed marine area (LMMA), a form of MPA in the Pacific region. To do this we analyse survey data at both the household and village level in Kadavu, an administrative province of Fiji. We find there are differences in economic activity and diet between the communities but little difference in overall income and wealth. Our study shows that villages with an active tabu area have more positive social outcomes in terms of perceptions of LMMAs. However, there are some notable negative social outcomes as well. In particular, we find that households not engaged in commercial fishing perceive conflict around the management of marine resources. We also find that households engaged in commercial fishing believe penalties for violating LMMA rules are high. Together, these results could potentially impede the adoption of LMMAs and tabu areas. Overall, our survey results do not indicate that tabu areas are detrimental or beneficial on the whole, either economically and socially

    <sup>14</sup>N overtone transition in double rotation solid-state NMR

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    Solid-state NMR transitions involving outer energy levels of the spin-1 14N nucleus are immune, to first order in perturbation theory, to the broadening caused by the nuclear quadrupole interaction. The corresponding overtone spectra, when acquired in conjunction with magic-angle sample spinning, result in lines, which are just a few kHz wide, permitting the direct detection of nitrogen compounds without the need for labeling. Despite the success of this technique, “overtone” resonances are still broadened due to indirect, second order effects arising from the large quadrupolar interaction. Here we demonstrate that another order of magnitude in spectral resolution may be gained by using double rotation. This brings the width of the 14N solid-state NMR lines much closer to the region commonly associated with high-resolution solid-state NMR spectroscopy of 15N and demonstrates the improvements in resolution that may be possible through the development of pulsed methodologies to suppress these second order effects

    The comparative performance of three screening questionnaires for psoriatic arthritis in a primary care surveillance study

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    Objectives: The objective of this study was to compare the performance of three PsA screening questionnaires in a primary care psoriasis surveillance study. Methods: Participants with psoriasis, and not known to have PsA, were identified from general practice databases and invited to attend a secondary care centre for a clinical assessment. The three patient-completed screening questionnaires (PEST, CONTEST and CONTESTjt) were administered, along with other patient-reported measures, and a clinical examination of skin and joints was performed. Participants who demonstrated signs of inflammatory arthritis suggestive of PsA were referred, via their GP, for a further assessment in a secondary care rheumatology clinic. Results: A total of 791 participants attended the screening visit, and 165 participants were judged to have signs and symptoms of inflammatory arthritis, of which 150 were referred for assessment. Of these, 126 were seen and 48 were diagnosed with PsA. The results for each questionnaire were as follows: PEST: sensitivity 0.625 (95% CI 0.482, 0.749), specificity 0.757 (0.724, 0.787); CONTEST: sensitivity 0.604 (0.461, 0.731), specificity 0.768 (0.736, 0.798); and CONTESTjt: sensitivity 0.542 (0.401, 0.676), specificity 0.834 (0.805, 0.859). CONTESTjt demonstrated marginally superior specificity to PEST, though the area under the ROC curve was similar for all three instruments. Conclusion: Minimal differences between the three screening questionnaires were found in this study, and no preferred questionnaire is indicated by these results. The choice of which instrument to choose will depend on other factors, such as simplicity and low patient burden

    Stability of Relativistic Matter With Magnetic Fields

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    Stability of matter with Coulomb forces has been proved for non-relativistic dynamics, including arbitrarily large magnetic fields, and for relativistic dynamics without magnetic fields. In both cases stability requires that the fine structure constant alpha be not too large. It was unclear what would happen for both relativistic dynamics and magnetic fields, or even how to formulate the problem clearly. We show that the use of the Dirac operator allows both effects, provided the filled negative energy `sea' is defined properly. The use of the free Dirac operator to define the negative levels leads to catastrophe for any alpha, but the use of the Dirac operator with magnetic field leads to stability.Comment: This is an announcement of the work in cond-mat/9610195 (LaTeX

    Aggregatibacter Actinomycetemcomitans Leukotoxin Cytotoxicity Occurs Through Bilayer Destabilization

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    The Gram-negative bacterium, Aggregatibacter actinomycetemcomitans, is a common inhabitant of the human upper aerodigestive tract. The organism produces an RTX (Repeats in ToXin) toxin (LtxA) that kills human white blood cells. LtxA is believed to be a membrane-damaging toxin, but details of the cell surface interaction for this and several other RTX toxins have yet to be elucidated. Initial morphological studies suggested that LtxA was bending the target cell membrane. Because the ability of a membrane to bend is a function of its lipid composition, we assessed the proficiency of LtxA to release of a fluorescent dye from a panel of liposomes composed of various lipids. Liposomes composed of lipids that form nonlamellar phases were susceptible to LtxA-induced damage while liposomes composed of lipids that do not form non-bilayer structures were not. Differential scanning calorimetry demonstrated that the toxin decreased the temperature at which the lipid transitions from a bilayer to a nonlamellar phase, while 31P nuclear magnetic resonance studies showed that the LtxA-induced transition from a bilayer to an inverted hexagonal phase occurs through the formation of an isotropic intermediate phase. These results indicate that LtxA cytotoxicity occurs through a process of membrane destabilization. © 2012 Blackwell Publishing Ltd

    Measuring velocity of sound with nuclear resonant inelastic x-ray scattering

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    Nuclear resonant inelastic x-ray scattering is used to measure the projected partial phonon density of states of materials. A relationship is derived between the low-energy part of this frequency distribution function and the sound velocity of materials. Our derivation is valid for harmonic solids with Debye-like low-frequency dynamics. This method of sound velocity determination is applied to elemental, composite, and impurity samples which are representative of a wide variety of both crystalline and noncrystalline materials. Advantages and limitations of this method are elucidated
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