159 research outputs found

    Threatened, endemic and harvested – two overlooked European skates

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    Sandy ray Leucoraja circularis and shagreen ray L. fullonica are large-bodied skate species occurring in the Northeast Atlantic and Mediterranean on the edge of the continental shelf and upper slope. These areas are not sampled effectively by fishery-independent trawl surveys, and fisheries-dependent data are also limited, as these species are landed as a bycatch. Consequently, there are no formal assessments or reference points, even though they are harvested as part of the Total Allowable Catch (TAC) for generic skates and rays. The implementation of data-limited assessment methods is often reliant on robust life-history data, which was lacking. Therefore, biological data were collected from 116 specimens of L. circularis (21–116 cm LT) and 54 specimens of L. fullonica (19–100 cm LT). Length at 50% maturity for L. circularis was estimated at 81 cm LT and 100 cm LT for males and females, respectively. This large size at maturity makes them more biologically vulnerable than other skate species managed under the generic TAC. This inherent vulnerability, low representation of mature individuals in trawl surveys and bycatch risk due to spatial overlap with important commercial fisheries suggests that both species, assessed as Threatened, would benefit from precautionary species-specific management measures. L. circularis and L. fullonica are respectively, the only IUCN listed Endangered and Vulnerable elasmobranchs that are endemic to Europe and also occur in UK waters. Therefore, with the eastern Atlantic being the main part of their distribution, urgent research and management action is of even greater importance to conserve them

    Nianga, laboratoire de l'agriculture irriguée en moyenne vallée du Sénégal

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    Les actes de l'atelier "Nianga" réunissent des analyses et des points de vue de différents spécialistes qui s'interessent à l'expérience et au devenir de la culture irriguée dans la vallée alluviale de la région du fleuve Sénégal et de son insertion dans les sytèmes de productio

    Measuring children’s involvement as an indicator of curriculum effectiveness : a curriculum evaluation of a selected child study centre in Singapore

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    This paper presents one aspect of a research project evaluating a curriculum model of a selected child study centre in Singapore. An issue of worldwide interest and concern is the ‘quality of learning’ debate as it relates to early childhood centres. In Singapore, the government is focusing on expansion in child care settings and increases in the amount of funded training. One of the issues surrounding prior-to-school education raises the question of how one measures the quality of teaching and learning, to describe the value of using, funding and promoting early education. The research reported in this study used a quasi experimental research paradigm to assess one aspect of the quality of a curriculum programme in a child study centre in Singapore. Children aged between 18 months and 6 years (N = 81) participated in the research. Using the observation scale of Laevers’ Child Involvement Scale, the active involvement of children in learning experiences was measured. The findings are presented and discussed

    Global Search for New Physics with 2.0/fb at CDF

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    Data collected in Run II of the Fermilab Tevatron are searched for indications of new electroweak-scale physics. Rather than focusing on particular new physics scenarios, CDF data are analyzed for discrepancies with the standard model prediction. A model-independent approach (Vista) considers gross features of the data, and is sensitive to new large cross-section physics. Further sensitivity to new physics is provided by two additional algorithms: a Bump Hunter searches invariant mass distributions for "bumps" that could indicate resonant production of new particles; and the Sleuth procedure scans for data excesses at large summed transverse momentum. This combined global search for new physics in 2.0/fb of ppbar collisions at sqrt(s)=1.96 TeV reveals no indication of physics beyond the standard model.Comment: 8 pages, 7 figures. Final version which appeared in Physical Review D Rapid Communication

    Observation of Orbitally Excited B_s Mesons

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    We report the first observation of two narrow resonances consistent with states of orbitally excited (L=1) B_s mesons using 1 fb^{-1} of ppbar collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We use two-body decays into K^- and B^+ mesons reconstructed as B^+ \to J/\psi K^+, J/\psi \to \mu^+ \mu^- or B^+ \to \bar{D}^0 \pi^+, \bar{D}^0 \to K^+ \pi^-. We deduce the masses of the two states to be m(B_{s1}) = 5829.4 +- 0.7 MeV/c^2 and m(B_{s2}^*) = 5839.7 +- 0.7 MeV/c^2.Comment: Version accepted and published by Phys. Rev. Let

    Search for the standard model Higgs boson in tau final states

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    We present a search for the standard model Higgs boson using hadronically decaying tau leptons, in 1 inverse femtobarn of data collected with the D0 detector at the Fermilab Tevatron ppbar collider. We select two final states: tau plus missing transverse energy and b jets, and tau+ tau- plus jets. These final states are sensitive to a combination of associated W/Z boson plus Higgs boson, vector boson fusion and gluon-gluon fusion production processes. The observed ratio of the combined limit on the Higgs production cross section at the 95% C.L. to the standard model expectation is 29 for a Higgs boson mass of 115 GeV.Comment: publication versio

    Search for W' bosons decaying to an electron and a neutrino with the D0 detector

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    This Letter describes the search for a new heavy charged gauge boson W' decaying into an electron and a neutrino. The data were collected with the D0 detector at the Fermilab Tevatron proton-antiproton Collider at a center-of-mass energy of 1.96 TeV, and correspond to an integrated luminosity of about 1 inverse femtobarn. Lacking any significant excess in the data in comparison with known processes, an upper limit is set on the production cross section times branching fraction, and a W' boson with mass below 1.00 TeV can be excluded at the 95% C.L., assuming standard-model-like couplings to fermions. This result significantly improves upon previous limits, and is the most stringent to date.Comment: submitted to Phys. Rev. Let

    Search for the associated production of a b quark and a neutral supersymmetric Higgs boson which decays to tau pairs

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    We report results from a search for production of a neutral Higgs boson in association with a bb quark. We search for Higgs decays to τ\tau pairs with one τ\tau subsequently decaying to a muon and the other to hadrons. The data correspond to 2.7fb1^{-1} of \ppbar collisions recorded by the D0 detector at s=1.96\sqrt{s} = 1.96TeV. The data are found to be consistent with background predictions. The result allows us to exclude a significant region of parameter space of the minimal supersymmetric model.Comment: Submitted to Phys. Rev. Letter

    Intestinal microbiome composition and its relation to joint pain and inflammation

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    Macrophage-mediated inflammation is thought to have a causal role in osteoarthritis-related pain and severity, and has been suggested to be triggered by endotoxins produced by the gastrointestinal microbiome. Here we investigate the relationship between joint pain and the gastrointestinal microbiome composition, and osteoarthritis-related knee pain in the Rotterdam Study; a large population based cohort study. We show that abundance of Streptococcus species is associated with increased knee pain, which we validate by absolute quantification of Streptococcus species. In addition, we replicate these results in 867 Caucasian adults of the Lifelines-DEEP study. Finally we show evidence that this association is driven by local inflammation in the knee joint. Our results indicate the microbiome is a possible therapeutic target for osteoarthritis-related knee pain

    Infrasound as a cue for seabird navigation

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    Seabirds are amongst the most mobile of all animal species and spend large amounts of their lives at sea. They cross vast areas of ocean that appear superficially featureless, and our understanding of the mechanisms that they use for navigation remains incomplete, especially in terms of available cues. In particular, several large-scale navigational tasks, such as homing across thousands of kilometers to breeding sites, are not fully explained by visual, olfactory or magnetic stimuli. Low-frequency inaudible sound, i.e., infrasound, is ubiquitous in the marine environment. The spatio-temporal consistency of some components of the infrasonic wavefield, and the sensitivity of certain bird species to infrasonic stimuli, suggests that infrasound may provide additional cues for seabirds to navigate, but this remains untested. Here, we propose a framework to explore the importance of infrasound for navigation. We present key concepts regarding the physics of infrasound and review the physiological mechanisms through which infrasound may be detected and used. Next, we propose three hypotheses detailing how seabirds could use information provided by different infrasound sources for navigation as an acoustic beacon, landmark, or gradient. Finally, we reflect on strengths and limitations of our proposed hypotheses, and discuss several directions for future work. In particular, we suggest that hypotheses may be best tested by combining conceptual models of navigation with empirical data on seabird movements and in-situ infrasound measurements
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