87,593 research outputs found

    Dispersion of material by wind and tide in shallow seas

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    Mixing processes in shallow seas are of particular importance in the dispersion of pollution (e.g. oil slicks) as well as in the distribution of sediment and biological material (e.g. phytoplankton and fish larvae). This study aims to further investigate the processes of wind-driven Langmuir circulation and bottom-generated turbulence and to quantify the effects they have on the dispersion of buoyant material. A numerical and analytical study is made of the dispersion of a plume of floating particles under the combined action of Langmuir circulation and a mean current. The numerical simulations show the general patterns the plume will form, with initial meanders leading to the formation of distinct windrows. The analytical model shows that the lateral diffusivity, the rate of across-current dispersion of the particles, is greatest when the angle between the direction of the wind and current is between 30° and 120°, and when the wind speed is large in comparison to the current speed. Further, it is found that the effects of Langmuir circulation will dominate the dispersion process when the wind speed is greater than about 10 times the current speed. Acoustic and visual observations of the surface effects of bottom-generated turbulence in a tidally-influenced and well-mixed region of the North Sea are presented. Although the sea bed in the area is flat, it is found that at any one time 20-30% of the water surface is affected by boils - circular regions of local upwelling - of diameter 0.9±0.2 times the water depth. The signature of individual boils persists for at least 7 minutes and, in accordance with laboratory and numerical studies, shows the appearance of eddies. Again, analytical and numerical models are constructed to estimate the effects of the boils on the dispersion of floating particles. The numerical simulations provide good qualitative agreement with the patterns observed in visual images of the dispersion of oil. Further, the horizontal diffusivities calculated by both them and the analytical methods show that the presence of boils can account for the dispersion measured by experimental methods in shallow tidal seas. In summarising and discussing the main findings of this work, particular emphasisis placed on the need for further observations of these two processes, in particular the boils and eddies and their interaction with the Langmuir circulation, to further improve the estimates of dispersion

    Electromyogram changes during sustained contraction after resistance training in women in their 3rd and 8th decades

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    The present study aimed at investigating the neuromuscular adaptations to 6 weeks of resistance training in women in their third (6 experimental, 8 controls) and eighth decades (8 experimental, 8 controls). The surface electromyogram (sEMG) was measured from the biceps brachii muscle during constant-force isometric contractions lasting 12 s at 80% of maximal voluntary contraction (MVC). All the signals were analysed adopting in the time domain the root mean square (RMS) as a measure of amplitude and in the frequency domain the median frequency (MDF) of the power spectrum. Quantitative analysis was performed from the 3rd to the 6th second, to describe the early phase of the contraction ("Early"), starting from point at which 80% of the MVC was reached, and from the 9th to the 12th second, to describe the last part of the constant-force sustained contraction ("Late"). After training, the MVC increased by 22.4% in the young (P &lt; 0.0001) and by 13.4% in the older (P &lt; 0.05) women. The "Early" RMS increased by 60.4% with respect to the pre-training condition in the young (P &lt; 0.01) but not in the older women. In contrast, the "Late" RMS increased by 46.7% in the older (P &lt; 0.05) but not in the young women. The MDF remained unchanged in both groups. These results indicate that young and older women showed different training-induced adaptation of the motor unit (MU) activation pattern, in order to keep a constant level of force during a sustained isometric contraction at 80% of MVC.</p

    Brain, spinal and nerve injury treatment.

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    PATENT: R. Vink, A.J.Nimmo. US 2005/0107380 A1 (PCT/AU01/00046) filed Jan 18, 2001; published Jan 11, 2005.A treatment for brain, spinal and nerve injury comprising use of a substance P receptor antagonist optionally in combination with a magnesium compound. There is also provided a formulation for use in this treatment comprising a substance P receptor antagonist and a magnesium compound.Invented by R. Vink, A.J.Nimmo; Hoffmann La-Roche agents for inventors

    A rigid and weathered ice shell on Titan

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    Several lines of evidence suggest that Saturn's largest moon, Titan, has a global subsurface ocean beneath an outer ice shell 50 to 200 kilometres thick. If convection is occurring, the rigid portion of the shell is expected to be thin; similarly, a weak, isostatically compensated shell has been proposed to explain the observed topography. Here we report a strong inverse correlation between gravity and topography at long wavelengths that are not dominated by tides and rotation. We argue that negative gravity anomalies (mass deficits) produced by crustal thickening at the base of the ice shell overwhelm positive gravity anomalies (mass excesses) produced by the small surface topography, giving rise to this inverse correlation. We show that this situation requires a substantially rigid ice shell with an elastic thickness exceeding 40 kilometres, and hundreds of metres of surface erosion and deposition, consistent with recent estimates from local features. Our results are therefore not compatible with a geologically active, low-rigidity ice shell. After extrapolating to wavelengths that are controlled by tides and rotation, we suggest that Titan's moment of inertia may be even higher (that is, Titan may be even less centrally condensed) than is currently thought

    Variations on the Author

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    “Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship

    The effect of exercise on plasma soluble IL-6 receptor concentration: a dichotomous response

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    The aim of this article is to review current literature on the response of soluble interleukin-6 receptor to exercise and identify a potential role for sIL-6R in skeletal muscle function. We also provide novel data on the impact of eccentric exercise on circulating levels. The aim of the research study was to investigate changes in plasma concentration of soluble interleukin-6 receptor (sIL-6R) and soluble glycoprotein 130 (sgp130) during recovery from exercise-induced muscle damage (EIMD) up to 72 h and their relationship with delayed onset muscle soreness (DOMS) and muscle function. 18 participants attended the laboratory on 4 consecutive days. On the first day, participants completed 6 sets of 10 repetitions of unilateral eccentric-concentric knee flexions at a test speed of 1.05 rad.s(-1) using a Cybex Isokentic dynamometer to induce muscle damage of the hamstrings. Prior to the eccentric exercise bout and each subsequent morning, following an overnight fast, participants had a venous blood sample taken which was centrifuged immediately and plasma frozen at -80 degrees C until later analysis. Plasma IL-6 and sgp130 were unchanged at any time point during recovery but sIL-6R was significantly reduced at 48 h and 72 h post-exercise (p < 0.05). Plasma sIL-6R was correlated with DOMS at 48 h post EIMD (r = 0.45, p < 0.05) and peak muscle torque at 24 h and 48 h following EIMD (r = -.42; p < 0.05; r = -.57; p < 0.01 respectively). Our novel finding that sIL-6R concentrations are decreased 2-3 days following a single bout of EIMD may reflect a regulatory mechanism controlling the influx of different leukocyte subpopulations into damaged tissue, although this needs to be confirmed by future studies. Our data suggests an association between sIL-6R, perception of pain and reduced peak muscle performance post-EIMD but further investigation is warranted to explore this relationship and implications for exercise performance

    [Newspaper Clipping: Author Claims Evidence of Second JFK Assassin #1]

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    Newspaper article titled "Author Claims Evidence of Second JFK Assassin." The article states that author Richard J. Whalen concluded "that there is circumstantial evidence to support the theory of a second assassin in the shooting of President John F. Kennedy.

    Also By The Same Author: AKTiveAuthor, a Citation Graph Approach to Name Disambiguation

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    The desire for definitive data and the semantic web drive for inference over heterogeneous data sources requires co-reference resolution to be performed on those data. In particular, name disambiguation is required to allow accurate publication lists, citation counts and impact measures to be determined. This paper describes a graph-based approach to author disambiguation on large-scale citation networks. Using self-citation, co-authorship and document source analyses, AKTiveAuthor clusters papers, achieving precision of 0.997 and recall of 0.818 over a test group of eight surname clusters
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