1,991 research outputs found

    Exploring the Information Base Needed for Sustainable Management of Rangeland Resources for Improved Livelihoods

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    Pastoralism is one of the most sustainable production systems worldwide and plays a major role in safeguarding ecosystem services and biodiversity in rangelands. The unique biological and cultural diversity of rangelands contributes to goods, services and knowledge that benefit humans also beyond the herding communities. Yet data currently available on grassland, forestry, agriculture and livestock are inadequate for informing policymaking on rangeland-based livestock systems. A review of global environmental assessments, online databases, peer-reviewed literature and international project documents showed that available information seldom disaggregates rangelands from other ecosystems or pastoralists from other rural dwellers. Few peer-reviewed publications address pastoral and rangeland issues combined. While some international projects present contextualised information on cases of pastoralism and rangelands, most do not share the data on their websites. A challenge encountered when seeking information is the inconsistency in defining pastoralists and rangelands. Estimates of the total number of pastoralists vary from 22 million to over half a billion; estimates of area covered by rangelands vary from 18% to 80% of the world’s land surface. The variation in definitions and lack of disaggregation of data lead to significant knowledge gaps on the condition and trends of pastoralism and rangelands. These therefore tend to be devalued. Underrating benefits of livestock mobility and inaccurate data on rangeland degradation could cause governments to blame and dismantle traditionally sustainable pastoral systems – in other words, ‘fix’ something that’s not broken. Without good data on pastoralists and rangelands, the impacts of current policies on these livelihoods and ecosystems cannot be assessed, and sustainable use and management of rangelands for improved livelihoods may be hindered. Improving the information base is high on the agenda of the initiative for an International Year of Rangelands and Pastoralists to increase global awareness of the importance of rangelands and pastoralists for livelihoods and healthy ecosystems

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    Recombination of H3+ Ions in the Afterglow of a He-Ar-H2 Plasma

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    Recombination of H3+ with electrons was studied in a low temperature plasma in helium. The plasma recombination rate is driven by two body, H3+ + e, and three-body, H3+ + e + He, processes with the rate coefficients 7.5x10^{-8}cm3/s and 2.8x10^{-25}cm6/s correspondingly at 260K. The two-body rate coefficient is in excellent agreement with results from storage ring experiments and theoretical calculations. We suggest that the three-body recombination involves formation of highly excited Rydberg neutral H3 followed by an l- or m- changing collision with He. Plasma electron spectroscopy indicates the presence of H3.Comment: 4 figure

    Complete TcT_c suppression and N\'eel triplets-mediated exchange in antiferromagnet-superconductor-antiferromagnet trilayers

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    An antiferromagnetic insulator (AFI) bearing a compensated interface to an adjacent conventional superconductor (S) has recently been predicted to generate N\'eel triplet Cooper pairs, whose amplitude alternates sign in space. Here, we theoretically demonstrate that such N\'eel triplets enable control of the superconducting critical temperature in an S layer via the angle between the N\'eel vectors of two enclosing AFI layers. This angle dependence changes sign with the number of S monolayers providing a distinct signature of the N\'eel triplets. Furthermore, we show that the latter mediate a similarly distinct exchange interaction between the two AFIs' N\'eel vectors.Comment: 7 pages, 4 figure

    Exploring the eDNA dynamics of the host-pathogen pair Pacifastacus leniusculus (Decapoda) and Aphanomyces astaci (Saprolegniales) under experimental conditions

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    The oomycete Aphanomyces astaci causes crayfish plague, a disease threatening native European crayfish. It is carried and transmitted by American crayfish species, which are the original hosts of A. astaci. In recent years, environmental DNA (eDNA) methods have been successfully implemented to monitor the spread of both A. astaci and its hosts. However, still little is known about how population density and other environmental factors influence the detectability of this host-pathogen complex. In a mesocosm experiment, we tested the influence of crayfish density, temperature and food availability on the detectability of eDNA for A. astaci and its host, signal crayfish Pacifastacus leniusculus. We also compared eDNA results with crayfish population density measured by catch per unit effort (CPUE) from two lakes with varying crayfish density and A. astaci prevalence. The mesocosm experiment revealed that a limited set of controlled factors can substantially change the detectable amount of eDNA, even though the physical presence of the target organisms remains the same. In cold, clear water, eDNA quantities of both targets increased far more than in a linear fashion with increased crayfish density. However, the presence of food decreased the detectability of crayfish eDNA, presumably through increased microbial-induced eDNA degradation. For A. astaci, where eDNA typically represents living spores, food did not affect the detectability. However, high water temperature strongly reduced it. The increased complexity and variability of factors influencing eDNA concentration under natural conditions, compared to a controlled experimental environment, suggests that establishing a reliable relationship between eDNA quantities and crayfish density is difficult to achieve. This was also supported by field data, where we found minimal correspondence between eDNA quantity and CPUE data. A comparison between quantitative real-time PCR (qPCR) analysis and droplet-digital PCR (ddPCR) analysis revealed higher detection success of the targets in field samples when using qPCR. Overall, our results support eDNA as an effective tool for presence-absence monitoring, but it seems less suited for biomass quantification and population density estimates. Detection of A. astaci and P. leniusculus is not influenced uniformly by respective environmental factors. Consequently, we recommend a strategy of monitoring both targets, where the detection of one may point towards the presence of the other

    Quasienergy Spectroscopy of Excitons

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    We theoretically study nonlinear optics of excitons under intense THz irradiation. In particular, the linear near infrared absorption and resonantly enhanced nonlinear sideband generation are described. We predict a rich structure in the spectra which can be interpreted in terms of the quasienergy spectrum of the exciton, via a remarkably transparent expression for the susceptibility, and show that the effects of strongly avoided quasienergy crossings manifest themselves directly, both in the absorption and transmitted sidebands.Comment: 4 pages RevTex, 3 eps figs included, as publishe

    HATS Abstract Behavioral Specification: The Architectural View

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    The Abstract Behavioral Specification (ABS) language is a formal, executable, object-oriented, concurrent modeling language intended for behavioral modeling of complex software systems that exhibit a high degree of variation, such as software product lines. We give an overview of the architectural aspects of ABS: a feature-driven development workflow, a formal notion of deployment components for specifying environmental constraints, and a dynamic component model that is integrated into the language. We employ an industrial case study to demonstrate how the various aspects work together in practic

    Efficacy of different types of cognitive enhancers for patients with schizophrenia. A meta-analysis

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    Cognitive impairment is a core feature of schizophrenia, which is predictive for functional outcomes and is, therefore, a treatment target in itself. Yet, literature on efficacy of different pharmaco-therapeutic options is inconsistent. This quantitative review provides an overview of studies that investigated potential cognitive enhancers in schizophrenia. We included pharmacological agents, which target different neurotransmitter systems and evaluated their efficacy on overall cognitive functioning and seven separate cognitive domains. In total, 93 studies with 5630 patients were included. Cognitive enhancers, when combined across all different neurotransmitter systems, which act on a large number of different mechanisms, showed a significant (yet small) positive effect size of 0.10 (k = 51, p = 0.023; 95% CI = 0.01 to 0.18) on overall cognition. Cognitive enhancers were not superior to placebo for separate cognitive domains. When analyzing each neurotransmitter system separately, agents acting predominantly on the glutamatergic system showed a small significant effect on overall cognition (k = 29, Hedges’ g = 0.19, p = 0.01), as well as on working memory (k = 20, Hedges’ g = 0.13, p = 0.04). A sub-analysis of cholinesterase inhibitors (ChEI) showed a small effect on working memory (k = 6, Hedges’ g = 0.26, p = 0.03). Other sub-analyses were positively nonsignificant, which may partly be due to the low number of studies we could include per neurotransmitter system. Overall, this meta-analysis showed few favorable effects of cognitive enhancers for patients with schizophrenia, partly due to lack of power. There is a lack of studies involving agents acting on other than glutamatergic and cholinergic systems, especially of those targeting the dopaminergic system
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