To determine the accuracy of a new actigraphy system for the measurement of periodic leg movements (PLMs). Continuous measurements of leg movements, made overnight, are essential to diagnose and ...monitor treatment for PLMs. We have developed the Actiwatch with Cambridge Neuro-Technology Ltd (Cambridge, UK) to detect leg movements consistent with PLMs, to record these movements from both feet over three consecutive nights and to report standard indices of PLMs. We describe three studies designed to validate this device.
The Actiwatch was assessed on a bench model across a range of movement amplitudes. The level of agreement on individual movements between the Actiwatch and bilateral anterior tibialis electromyography (BATEMG) measures was assessed in 199 epochs from five patients with known PLMs. The ability of the Actiwatch to correctly identify patients with PLMs was assessed in a comparison with polysomnography (PSG) in 50 consecutive patients investigated in the sleep laboratory.
The Actiwatch detected all mechanically generated movements (100% sensitivity and 100% specificity) on the bench test. On individual movements BATEMG measurement and the Actiwatch agreed on 94% of epochs. The sensitivity and specificity of the Actiwatch to detect leg movements in severe PLMs as defined by BATEMG (PLMI≥25) are high (100% sensitive and 97% specific). Our bilateral system gave better agreement with BATEMG than previous systems but the two measures are still not interchangeable.
EMG is only a surrogate measure of limb movement and indices measured in this way correlate poorly with symptoms. We have demonstrated that the Actiwatch faithfully records movement, which offers the potential to reassess the relationships between limb movement indices and symptoms. This which offers a convenient and economical alternative to PSG in the study of large populations to increase our understanding of the epidemiology and clinical significance of PLMs.
A recent study showed that a critically endangered migratory predator species, the Balearic shearwater Puffinus mauretanicus, rapidly expanded northwards in northeast Atlantic waters after the ...mid-1990s. As a significant positive correlation was found between the long-term changes in the abundance of this seabird and sea temperature around the British Isles, it was hypothesized that the link between the biogeographic shift and temperature occurred through the food web. Here, we test this conjecture and reveal concomitant changes in a regional index of sea temperature, plankton (total calanoid copepod), fish prey (anchovy and sardine) and the Balearic shearwater for the period 1980–2003. All three trophic levels exhibit a significant shift detected between 1994 and 1996. Our findings therefore support the assertion of both a direct and an indirect effect of climate change on the spatial distribution of post-breeding Balearic shearwater through a trophic cascade.
The standard model of particle physics contains parameters-such as particle masses-whose origins are still unknown and which cannot be predicted, but whose values are constrained through their ...interactions. In particular, the masses of the top quark (Mt) and W boson (MW) constrain the mass of the long-hypothesized, but thus far not observed, Higgs boson. A precise measurement of Mt can therefore indicate where to look for the Higgs, and indeed whether the hypothesis of a standard model Higgs is consistent with experimental data. As top quarks are produced in pairs and decay in only about 10-24 s into various final states, reconstructing their masses from their decay products is very challenging. Here we report a technique that extracts more information from each top-quark event and yields a greatly improved precision (of ± 5.3 GeV/c2) when compared to previous measurements. When our new result is combined with our published measurement in a complementary decay mode and with the only other measurements available, the new world average for Mt becomes 178.0 ± 4.3 GeV/c2. As a result, the most likely Higgs mass increases from the experimentally excluded value of 96 to 117 GeV/c2, which is beyond current experimental sensitivity. The upper limit on the Higgs mass at the 95% confidence level is raised from 219 to 251 GeV/c2.
The inclusive e+psingle and double differential cross sections for neutral and charged current processes are measured with the H1 detector at HERA. The data were taken in 1999 and 2000 at a ...centre-of-mass energy of \(\sqrt{s} = 319{\rm GeV}\) and correspond to an integrated luminosity of 65.2 pb-1. The cross sections are measured in the range of four-momentum transfer squared Q2 between 100 and \(30 000{\rm GeV}^2\) and Bjorken x between 0.0013 and 0.65. The neutral current analysis for the new e+p data and the earlier e-p data taken in 1998 and 1999 is extended to small energies of the scattered electron and therefore to higher values of inelasticity y, allowing a determination of the longitudinal structure function FL at high Q2 (\(110-700{\rm GeV}^2\)). A new measurement of the structure function \(x\tilde{F}_3\) is obtained using the new e+p and previously published \(e^\pm p\) neutral current cross section data at high Q2. These data together with H1 low Q2 precision data are further used to perform new next-to-leading order QCD analyses in the framework of the Standard Model to extract flavour separated parton distributions in the proton.
Here, we present a search for the pair production of scalar top quarks ($\sim\atop{t}$1), the lightest supersymmetric partners of the top quarks, in $p\bar{p}$ collisions at a center-of-mass energy ...of 1.96 TeV, using data corresponding to an integrated luminosity of 7.3fb-1 collected with the D0 experiment at the Fermilab Tevatron Collider. Each scalar top quark is assumed to decay into a b quark, a charged lepton, and a scalar neutrino (ν˜). We investigate final states arising from$\sim\atop{t}$1 $≂\atop{t}$1→$b\bar{b}$ μτ$\sim\atop{v}$$\sim\atop{v}$ and $\sim\atop{t}$1$≂\atop{t}$1→$b\bar{b}$ ττ$\sim\atop{v}$$\sim\atop{v}$. With no significant excess of events observed above the background expected from the standard model, we set exclusion limits on this production process in the (m$\sim\atop{t}$1, m$\sim\atop{v}$) plane.
La végétation de 12 cours d'eau répartis sur le territoire français a été étudiée selon le protocole standardisé d'échantillonnage «Milieu Et Végétaux aquatiques fixés» (M.E.V.) pour tester ce ...procotole. Le traitement des données par rivière puis pour l'ensemble des séquences étudiées permet d'établir des typologies floristiques. De façon préliminaire, le déterminisme de distribution des phytocénoses est envisagé. Les différences majeures s'expriment à l'amont en fonction de la géologie et de la minéralisation, des conditions d'écoulement et d'ombrage. Une homogénéisation s'effectue vers l'aval, à la faveur de l'eutrophisation et de l'accroissement des dimensions du cours d'eau. La dimension éco-régionale s'exprime d'abord au niveau de la géologie, et secondairement en fonction du climat (atlanticité) et des différences entre rivières de plaine et de piémont. Les résultats sont discutés en vue d'une amélioration du protocole et de la possibilité d'application de la notion de phytocénoses de référence.
The vegetation of 12 French rivers was studied to test the standardized protocol «Milieu Et Végétaux aquatiques fixés». Data processing for each river and then for all studied stretches gave floristic typologies and an assessment of the pattern of vegetation distribution. A wide diversity appeared upstream, due to geology and mineralization, flow and shade. Vegetation was more homogeneous downstream, following eutrophication and river width increase. The ecoregional features are mainly due to geology, then to distance from the sea and to opposition between foothill and lowland rivers. Results are discussed to improve the methodology, paying attention to reference phytocenosis concept.
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