2,551 research outputs found

    Subduction Duration and Slab Dip

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    The dip angles of slabs are among the clearest characteristics of subduction zones, but the factors that control them remain obscure. Here, slab dip angles and subduction parameters, including subduction duration, the nature of the overriding plate, slab age, and convergence rate, are determined for 153 transects along subduction zones for the present day. We present a comprehensive tabulation of subduction duration based on isotopic ages of arc initiation and stratigraphic, structural, plate tectonic and seismic indicators of subduction initiation. We present two ages for subduction zones, a longā€term age and a reinitiation age. Using cross correlation and multivariate regression, we find that (1) subduction duration is the primary parameter controlling slab dips with slabs tending to have shallower dips at subduction zones that have been in existence longer; (2) the longā€term age of subduction duration better explains variation of shallow dip than reinitiation age; (3) overriding plate nature could influence shallow dip angle, where slabs below continents tend to have shallower dips; (4) slab age contributes to slab dip, with younger slabs having steeper shallow dips; and (5) the relations between slab dip and subduction parameters are depth dependent, where the ability of subduction duration and overriding plate nature to explain observed variation decreases with depth. The analysis emphasizes the importance of subduction history and the longā€term regional state of a subduction zone in determining slab dip and is consistent with mechanical models of subduction

    Functional inspiratory muscle training (IMT) improves load carriage performance greater than traditional IMT techniques: 1652 Board #305 June 2, 9: 00 AM - 10: 30 AM.

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    The addition of external thoracic loads is common in occupational groups such as the military. The positioning upon the thorax poses a unique challenge to breathing mechanics and causes respiratory muscle fatigue (RMF) following exercise. IMT techniques provide a positive impact to exercise performance as well as attenuating RMF in both health and athletic populations. However in occupational groups, despite increased inspiratory muscle strength and performance, IMT has so far failed to attenuate RMF, potentially limiting the performance enhancement of IMT. It has been suggested that functional inspiratory muscle training (IMTF) may elicit performance adaptations above that of traditional IMT techniques as it targets the inspiratory muscles throughout the length-tension range adopted during exercise.N/

    Development of European standards for evaluative reporting in forensic science : The gap between intentions and perceptions

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    Criminal justice authorities of EU countries currently engage in dialogue and action to build a common area of justice and to help increase the mutual trust in judicial systems across Europe. This includes, for example, the strengthening of procedural safeguards for citizens in criminal proceedings by promoting principles such as equality of arms. Improving the smooth functioning of judicial processes is also pursued by works of expert working groups in the field of forensic science, such as the working parties under the auspices of the European Network of Forensic Science Institutes (ENFSI). This network aims to share knowledge, exchange experiences and come to mutual agreements in matters concerning forensic science practice, among them the interpretation of results of forensic examinations. For example, through its Monopoly Programmes (financially supported by the European Commission), ENFSI has funded a series of projects that come under the general theme ā€˜Strengthening the Evaluation of Forensic Results across Europeā€™. Although these initiatives reflect a strong commitment to mutual understanding on general principles of forensic interpretation, the development of standards for evaluation and reporting, including roadmaps for implementation within the ENFSI community, are fraught with conceptual and practical hurdles. In particular, experience through consultations with forensic science practitioners shows that there is a considerable gap between the intentions of a harmonised view on principles of forensic interpretation and the way in which works towards such common understanding are perceived in the community. In this paper, we will review and discuss several recurrently raised concerns. We acknowledge practical constraints such as limited resources for training and education, but we shall also argue that addressing topics in forensic interpretation now is of vital importance because forensic science continues to be challenged by proactive participants in the legal process that tend to become more demanding and less forgiving

    Overeducation across British regions

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    This paper analyses levels of over-education and wage returns to education for males across eleven regions of the UK using Labour Force Survey data. Significant differences are found in the probability of being over-educated across regions; also, differences are found in the return to the ā€˜correctā€™ level of education in each region, in each case associated with flexibility of movement between and into particular regions, which determines the ease of job matching. Furthermore, evidence is found that, after controlling for the level of education acquired, there exists a premium to the ā€˜correctā€™ level of education, which varies across UK regions

    Black hole production in tachyonic preheating

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    We present fully non-linear simulations of a self-interacting scalar field in the early universe undergoing tachyonic preheating. We find that density perturbations on sub-horizon scales which are amplified by tachyonic instability maintain long range correlations even during the succeeding parametric resonance, in contrast to the standard models of preheating dominated by parametric resonance. As a result the final spectrum exhibits memory and is not universal in shape. We find that throughout the subsequent era of parametric resonance the equation of state of the universe is almost dust-like, hence the Jeans wavelength is much smaller than the horizon scale. If our 2D simulations are accurate reflections of the situation in 3D, then there are wide regions of parameter space ruled out by over-production of black holes. It is likely however that realistic parameter values, consistent with COBE/WMAP normalisation, are safetly outside this black hole over-production region.Comment: 6pages, 7figures, figures correcte

    Are black holes over-produced during preheating?

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    We provide a simple but robust argument that primordial black hole (PBH) production generically does {\em not} exceed astrophysical bounds during the resonant preheating phase after inflation. This conclusion is supported by fully nonlinear lattice simulations of various models in two and three dimensions which include rescattering but neglect metric perturbations. We examine the degree to which preheating amplifies density perturbations at the Hubble scale and show that at the end of the parametric resonance, power spectra are universal, with no memory of the power spectrum at the end of inflation. In addition we show how the probability distribution of density perturbations changes from exponential on very small scales to Gaussian when smoothed over the Hubble scale -- the crucial length for studies of primordial black hole formation -- hence justifying the standard assumption of Gaussianity.Comment: 12 pages, 8 figures, revtex, added references for section

    Astrophysical constraints on primordial black holes in Brans-Dicke theory

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    We consider cosmological evolution in Brans-Dicke theory with a population of primordial black holes. Hawking radiation from the primordial black holes impacts various astrophysical processes during the evolution of the Universe. The accretion of radiation by the black holes in the radiation dominated era may be effective in imparting them a longer lifetime. We present a detailed study of how this affects various standard astrophysical constraints coming from the evaporation of primordial black holes. We analyze constraints from the present density of the Universe, the present photon spectrum, the distortion of the cosmic microwave background spectrum and also from processes affecting light element abundances after nucleosynthesis. We find that the constraints on the initial primordial black hole mass fractions are tightened with increased accretion efficiency.Comment: 15 page

    AVERT2(a very early rehabilitation trial, a very effective reproductive trigger): retrospective observational analysis of the number of babies born to trial staff

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    Objective: To report the number of participants needed to recruit per baby born to trial staff during AVERT, a large international trial on acute stroke, and to describe trial management consequences. Design: Retrospective observational analysis. Setting: 56 acute stroke hospitals in eight countries. Participants: 1074 trial physiotherapists, nurses, and other clinicians. Outcome measures: Number of babies born during trial recruitment per trial participant recruited. Results: With 198 site recruitment years and 2104 patients recruited during AVERT, 120 babies were born to trial staff. Births led to an estimated 10% loss in time to achieve recruitment. Parental leave was linked to six trial site closures. The number of participants needed to recruit per baby born was 17.5 (95% confidence interval 14.7 to 21.0); additional trial costs associated with each birth were estimated at 5736 Australian dollars on average. Conclusion: The staff absences registered in AVERT owing to parental leave led to delayed trial recruitment and increased costs, and should be considered by trial investigators when planning research and estimating budgets. However, the celebration of new life became a highlight of the annual AVERT collaboratorsā€™ meetings and helped maintain a cohesive collaborative group

    A robust protocol for in vivo THz skin measurements

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    This work presents an experimental setup to control the way in which pressure interferes with the repeatability of in vivo THz skin measurements. By integrating a pressure sensor circuit into our THz system, it is possible to identify which measurements were taken within a previously specified pressure range. The live response of the pressure sensor helps to acquire data within the desired pressure leading to greater consistency of data between measurements. Additionally, a protocol is proposed to help achieve repeatable results and to remove the effects of the natural variation of the skin through the course of the day. This technique has been shown to be able to quantify the changes induced in the skin following the application of a moisturising skin product and shows the measured result to be significantly different from natural skin variation. This research therefore prepares the way for further studies on the effectiveness of different skin products using in vivo THz measurements
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