867 research outputs found

    Persistence of Carex bigelowii–Racomitrium lanuginosum moss heath under sheep grazing in the Grampian Mountains, Scotland

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    Carex bigelowii–Racomitrium lanuginosum moss heath has been monitored on the summit of Glas Maol, Grampian Mountains, Scotland since 1990 to assess the impact of herbivores and snow-lie. This vegetation community has high conservation value in Britain, being near-natural and the habitat of some rare arctic-alpine birds. In recent decades, it has decreased in extent in British uplands, and changed in composition due to declining Racomitrium cover, with the main drivers believed to be heavy grazing and nitrogen deposition. Permanent plots were established for the monitoring, laid out at fixed distances from a ski corridor built in 1986. Sheep grazing was assessed by pellet-group counts, and botanical composition by point-quadrat analysis. Monitoring was in summer annually between 1990 and 1996, but less frequently since. The moss heath was found to retain its main characteristics from 1990 to 2008/09, with Carex bigelowii Torr. ex Schwein dominant and Racomitrium lanuginosum (Hedw.) Brid. having much cover. There was a small but significant increase in grasses, and lichens declined, but the community remained species-poor. Some ground experienced increased grazing pressure and suffered a temporary decline of Racomitrium, but recovery followed despite continuing substantial grazing. The species experiencing greatest change was Dicranum fuscescens Turner, which first increased but later lost most of its cover; its relationships to Racomitrium lanuginosum are discussed

    CN in prestellar cores

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    Determining the structure of and the velocity field in prestellar cores is essential to understanding protostellar evolution.} {We have observed the dense prestellar cores L 1544 and L 183 in the N=1→0N = 1 \to 0 rotational transition of CN and \thcn in order to test whether CN is depleted in the high--density nuclei of these cores.} {We have used the IRAM 30 m telescope to observe along the major and minor axes of these cores. We compare these observations with the 1 mm dust emission, which serves as a proxy for the hydrogen column density.}{We find that while CN\jone is optically thick, the distribution of \thcn\jone intensity follows the dust emission well, implying that the CN abundance does not vary greatly with density. We derive an abundance ratio of \rm [CN]/[\hh]=\dix{-9} in L 183 and 1-3\tdix{-9} in L 1544, which, in the case of L 183, is similar to previous estimates obtained by sampling lower--density regions of the core.}{We conclude that CN is not depleted towards the high--density peaks of these cores and thus behaves like the N-containing molecules \nnhp and \nhhh. CN is, to our knowledge, the first C--containing molecule to exhibit this characteristic.Comment: Accepted for publication in A&A Letter

    A conflict management tool for conservation agencies

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    1. Growing pressure on natural resources is leading to more conservation conflicts. Governments and their statutory agencies devote increasing financial and human resources to this subject, but tend to adopt reactive, ad hoc approaches to management. 2. We combined theory and empirical data about five conservation conflicts in a transdisciplinary collaboration to co-develop a novel decision-making tool. 3. This tool uses a systematic stepwise approach with six distinct decision stages: (i) establishing whether there is a conflict or an impact; (ii) understanding the context of the conflict, including the stakeholders affected; (iii) developing shared understanding of the conflict and goals; (iv) building a consensus on how to reach the goals; (v) implementing measures; and (vi) monitoring the outcomes. 4. Policy implications. We argue this new tool has wide applicability and democratic legitimacy and offers an exciting and practical approach to improve the management of conservation conflicts

    Nitrogen chemistry and depletion in starless cores

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    We investigated the chemistry of nitrogen--containing species, principally isotopomers of CN, HCN, and HNC, in a sample of pre-protostellar cores. We used the IRAM 30 m telescope to measure the emission in rotational and hyperfine transitions of CN, HCN, 13CN, H13CN, HN13C, and HC15N, in L 1544, L 183, Oph D, L 1517B, L 310. The observations were made along axial cuts through the dust emission peak, at a number of regularly--spaced offset positions. The observations were reduced and analyzed to obtain the column densities, using the measurements of the less abundant isotopic variants in order to minimize the consequences of finite optical depths in the lines. The observations were compared with the predictions of a free--fall gravitational collapse model, which incorporates a non-equilibrium treatment of the relevant chemistry. We found that CN, HCN, and HNC remain present in the gas phase at densities well above that at which CO depletes on to grains. The CN:HCN and the HNC:HCN abundance ratios are larger than unity in all the objects of our sample. Furthermore, there is no observational evidence for large variations of these ratios with increasing offset from the dust emission peak and hence with density. Whilst the differential freeze--out of CN and CO can be understood in terms of the current chemistry, the behaviour of the CN:HCN ratio is more difficult to explain. Models suggest that most nitrogen is not in the gas phase but may be locked in ices. Unambiguous conclusions require measurements of the rate coefficients of the key neutral--neutral reactions at low temperatures

    Shooting may aggravate rather than alleviate conflicts between migratory geese and agriculture

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    Many migratory goose populations have thrived over the past decades and their reliance on agricultural resources has often led to conflicts. Control and management measures are sought after but since migratory geese use several sites in their annual cycle, local management actions should consider their potential effects further down the flyway. We used a behaviour‐based migration model to illustrate the consequences of management actions involving hunting, derogation shooting and scaring at single or multiple locations along the flyway, considering various mechanisms of how geese might perceive shooting/hunting. Furthermore, as a proxy for the agricultural damage caused, we calculated the per capita biomass consumption between scenarios—both over time and cumulatively. We found that hunting, shooting and scaring can result in a suite of direct and indirect consequences on migration and foraging behaviour. Most importantly, hunting/shooting on a particular site had implications not only for the behaviour at the actual site but also for behaviour at, and use of, other sites. Furthermore, the specific consequences of shooting/hunting could be counter‐intuitive, that is, aggravate rather than alleviate agricultural damage, depending on where along the migration route changes had taken place and the mechanisms through which hunting/shooting was assumed to affect geese. Synthesis and applications . Management plans are being discussed or implemented for several migratory goose populations and often include shooting, hunting or scaring at one or multiple locations. Using a behaviour‐based model, we assessed the consequences of such local management measures and found that they can indeed lead to a reduction of agricultural conflicts locally but may also aggravate the conflict or shift it to other sites along the flyway. Thus, we recommend the use of these models to scrutinize the efficiency of specific management measures and to assist in identifying an international management regime that minimizes conflicts on a flyway level while still maintaining migratory populations

    Perturbation theory in a framework of iteration methods

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    In a previous paper (J. Phys. A 36, 11807 (2003)), we introduced the `asymptotic iteration method' for solving second-order homogeneous linear differential equations. In this paper, we study perturbed problems in quantum mechanics and we use the method to find the coefficients in the perturbation series for the eigenvalues and eigenfunctions directly, without first solving the unperturbed problem.Comment: 13 page

    Humoral responses to the measles, mumps and rubella vaccine are impaired in Leigh Syndrome French Canadian patients

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    Leigh Syndrome French Canadian (LSFC) is a rare autosomal recessive metabolic disorder characterized by severe lactic acidosis crises and early mortality. LSFC patients carry mutations in the Leucine Rich Pentatricopeptide Repeat Containing (LRPPRC) gene, which lead to defects in the respiratory chain complexes and mitochondrial dysfunction. Mitochondrial respiration modulates cellular metabolic activity, which impacts many cell types including the differentiation and function of immune cells. Hence, we postulated that, in addition to neurological and metabolic disorders, LSFC patients may show impaired immune activity. To gain insight into the quality of the immune response in LSFC patients, we examined the response to the measles, mumps and rubella (MMR) vaccine by measuring antibody titers to MMR in the plasma. In a cohort of eight LSFC patients, the response to the MMR vaccine was variable, with some individuals showing antibodies to all three viruses, while others had antibodies to two or fewer viruses. These results suggest that the mutations in the LRPPRC gene present in LSFC patients may affect the immune response to vaccines. Monitoring vaccine response in this fragile population should be considered to ensure full protection against pathogens

    Knowledge mobilization in the context of health technology assessment: an exploratory case study

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    <p>Abstract</p> <p>Background</p> <p>Finding measures to enhance the dissemination and implementation of their recommendations has become part of most health technology assessment (HTA) bodies' preoccupations. The Quebec government HTA organization in Canada observed that some of its projects relied on innovative practices in knowledge production and dissemination. A research was commissioned in order to identify what characterized these practices and to establish whether they could be systematized.</p> <p>Methods</p> <p>An exploratory case study was conducted during summer and fall 2010 in the HTA agency in order to determine what made the specificity of its context, and to conceptualize an approach to knowledge production and dissemination that was adapted to the mandate and nature of this form of HTA organization. Six projects were selected. For each, the HTA report and complementary documents were analyzed, and semi-structured interviews were carried out. A narrative literature review of the most recent literature reviews of the principal knowledge into practice frameworks (2005-2010) and of articles describing such frameworks (2000-2010) was undertaken.</p> <p>Results and discussion</p> <p>Our observations highlighted an inherent difficulty as regards applying the dominant knowledge translation models to HTA and clinical guidance practices. For the latter, the whole process starts with an evaluation question asked in a problematic situation for which an actionable answer is expected. The objective is to produce the evidence necessary to respond to the decision-maker's request. The practices we have analyzed revealed an approach to knowledge production and dissemination, which was multidimensional, organic, multidirectional, dynamic, and dependent on interactions with stakeholders. Thus, HTA could be considered as a knowledge mobilization process per se.</p> <p>Conclusions</p> <p>HTA's purpose is to solve a problem by mobilizing the types of evidence required and the concerned actors, in order to support political, organizational or clinical decision-making. HTA relies on the mediation between contextual, colloquial and scientific evidence, as well as on interactions with stakeholders for recommendation making. Defining HTA as a knowledge mobilization process might contribute to consider the different orders of knowledge, the social, political and ethical dimensions, and the interactions with stakeholders, among the essential components required to respond to the preoccupations, needs and contexts of all actors concerned with the evaluation question's issues.</p

    Natural and cultural heritage in mountain landscapes: towards an integrated valuation

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    Mountain areas of Europe have been managed by humans for a long time, leading to a prevalence of semi-natural habitats in mountain landscapes today. These landscapes contain both natural and cultural heritage; however, natural and cultural heritage are rarely considered together when valuing landscapes and developing management plans in protected areas. Here we present a case study of seven protected areas in the mountains of Great Britain and Norway. We take a long-term perspective on landscape and land-use change and propose an integrated model of landscape valuation on the basis of combined natural and cultural heritage. Our model plots indicators of natural and cultural heritage along a gradient of land-use intensity, allowing simultaneous assessment and highlighting how valuation depends on what type of heritage is considered. We show that while contemporary land-use changes follow similar trajectories in Norway and Britain, different land-use histories mean that the loss of heritage differs between the regions. The model presented here thus allows for the consolidation of valuation based on both cultural and natural heritage in landscapes.publishedVersio
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