1,052 research outputs found

    D.2.1.2 First integrated Grid infrastructure

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    National Plans of Action (NPOAs) for reducing seabird bycatch: Developing best practice for assessing and managing fisheries impacts

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    Fisheries bycatch is one of the biggest threats to seabird populations. Managers need to identify where and when bycatch occurs and ensure effective action. In 1999, the Food and Agriculture Organization of the United Nations released the International Plan of Action for Reducing Incidental Catch of Seabirds in Longline Fisheries (IPOA-s) encouraging states to voluntarily assess potential seabird bycatch problems and implement a National Plan of Action (NPOA) if needed. However, the IPOA-s is ambiguous about the steps and objectives, diminishing its value as a conservation tool

    European Society of Biomechanics S.M. Perren Award 2018: Altered biomechanical stimulation of the developing hip joint in presence of hip dysplasia risk factors

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    Fetal kicking and movements generate biomechanical stimulation in the fetal skeleton, which is important for prenatal musculoskeletal development, particularly joint shape. Developmental dysplasia of the hip (DDH) is the most common joint shape abnormality at birth, with many risk factors for the condition being associated with restricted fetal movement. In this study, we investigate the biomechanics of fetal movements in such situations, namely fetal breech position, oligohydramnios and primiparity (firstborn pregnancy). We also investigate twin pregnancies, which are not at greater risk of DDH incidence, despite the more restricted intra-uterine environment. We track fetal movements for each of these situations using cine-MRI technology, quantify the kick and muscle forces, and characterise the resulting stress and strain in the hip joint, testing the hypothesis that altered biomechanical stimuli may explain the link between certain intra-uterine conditions and risk of DDH. Kick force, stress and strain were found to be significantly lower in cases of breech position and oligohydramnios. Similarly, firstborn fetuses were found to generate significantly lower kick forces than non-firstborns. Interestingly, no significant difference was observed in twins compared to singletons. This research represents the first evidence of a link between the biomechanics of fetal movements and the risk of DDH, potentially informing the development of future preventative measures and enhanced diagnosis. Our results emphasise the importance of ultrasound screening for breech position and oligohydramnios, particularly later in pregnancy, and suggest that earlier intervention to correct breech position through external cephalic version could reduce the risk of hip dysplasia

    An overview of the impacts of fishing on seabirds, including identifying future research directions

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    Knowledge of fisheries impacts, past and present, is essential for understanding the ecology and conservation of seabirds, but in a rapidly changing world, knowledge and research directions require updating. In this Introduction and in the articles in this Themed Set “Impacts of fishing on seabirds”, we update our understanding of how fishing impacts seabird communities and identify areas for future research. Despite awareness of the problems and mitigation efforts for >20 years, fisheries still negatively impact seabirds via the effects of bycatch, competition, and discards. Bycatch continues to kill hundreds of thousands of seabirds annually, with negative population-level consequences. Fisheries for forage fish (e.g. anchovy, sandeel, and krill) negatively impact seabirds by competing for the same stocks. Historically, discards supplemented seabird diets, benefitting some species but also increasing bycatch rates and altering seabird community composition. However, declining discard production has led to potentially deleterious diet switches, but reduced bycatch rates. To improve research into these problems, we make the following recommendations: (1) improve data collection on seabird–vessel interaction and bycatch rates, on fishing effort and vessel movements (especially small-scale fleets), and on mitigation compliance, (2) counter the current bias towards temperate and high-latitude ecosystems, larger-bodied species and particular life stages or times of year (e.g. adults during breeding), and (3) advance our currently poor understanding of combined effects of fisheries and other threats (e.g. climate change, offshore renewables). In addition, research is required on under-studied aspects of fishing impacts: consequences for depleted sub-surface predators, impacts of illegal, unreported and unregulated fishing, artisanal and emerging fisheries, such as those targeting mesopelagic fish, have received insufficient research attention. Some of these shortfalls can be overcome with new tools (e.g. electronic monitoring, remote sensing, artificial intelligence, and big data) but quantifying and addressing fishing impacts on seabirds requires greater research investment at appropriate spatio-temporal scales, and more inclusive dialogue from grassroots to national and international levels to improve governance as fishing industries continue to evolve

    Analysis of three-nucleon forces effects in the A=3A=3 system

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    Using modern nucleon-nucleon interactions in the description of the A=3,4A=3,4 nuclear systems the χ2\chi^2 per datum results to be much bigger than one. In particular it is not possible to reproduce the three- and four-nucleon binding energies and the ndn-d scattering length simultaneously. This is one manifestation of the necessity of including a three-nucleon force in the nuclear Hamiltonian. In this paper we perform an analysis of some, widely used, three-nucleon force models. We analyze their capability to describe the aforementioned quantities and, to improve their description, we propose modifications in the parametrization of the models. The effects of these new parametrization are studied in some polarization observables at low energies.Comment: 10 pages, to be published in Few-Body Systems. Presented at the workshop on "Relativistic Description of Two- and Three-body Systems in Nuclear Physics" ECT* Trento, 19 - 23 October 200

    Renal crystal deposits and histopathology in patients with cystine stones

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    We have biopsied the papillae of patients who have cystine stones asking if this stone type is associated with specific tissue changes. We studied seven cystine stone formers (SF) treated with percutaneous nephrolithotomy using digital video imaging of renal papillae for mapping and obtained papillary biopsies. Biopsies were analyzed by routine light and electron microscopy, infrared spectroscopy, electron diffraction, and micro-CT. Many ducts of Bellini (BD) had an enlarged ostium, and all such were plugged with cystine crystals, and had injured or absent lining cells with a surrounding interstitium that was inflamed to fibrotic. Crystal plugs often projected into the urinary space. Many inner medullary collecting ducts (IMCD) were dilated with or without crystal plugging. Apatite crystals were identified in the lumens of loops of Henle and IMCD. Abundance of interstitial Randall's plaque was equivalent in amount to that of non-SF. In the cortex, glomerular obsolescence and interstitial fibrosis exceeded normal. Cystine crystallizes in BD with the probable result of cell injury, interstitial reaction, nephron obstruction, and with the potential of inducing cortical change and loss of IMCD tubular fluid pH regulation, resulting in apatite formation. The pattern of IMCD dilation, and loss of medullary structures is most compatible with such obstruction, either from BD lumen plugs or urinary tract obstruction from stones themselves

    Selected Topics in Three- and Four-Nucleon Systems

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    Two different aspects of the description of three- and four-nucleon systems are addressed. The use of bound state like wave functions to describe scattering states in NdN-d collisions at low energies and the effects of some of the widely used three-nucleon force models in selected polarization observables in the three- and four-nucleon systems are discussed.Comment: Presented at the 21st European Conference on Few-Body Problems in Physics, Salamanca, Spain, 30 August - 3 September 201

    Dynamics of ions in the selectivity filter of the KcsA channel

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    The statistical and dynamical properties of ions in the selectivity filter of the KcsA ion channel are considered on the basis of molecular dynamics (MD) simulations of the KcsA protein embedded in a lipid membrane surrounded by an ionic solution. A new approach to the derivation of a Brownian dynamics (BD) model of ion permeation through the filter is discussed, based on unbiased MD simulations. It is shown that depending on additional assumptions, ion’s dynamics can be described either by under-damped Langevin equation with constant damping and white noise or by Langevin equation with a fractional memory kernel. A comparison of the potential of the mean force derived from unbiased MD simulations with the potential produced by the umbrella sampling method demonstrates significant differences in these potentials. The origin of these differences is an open question that requires further clarifications

    Universal Correlations in Pion-less EFT with the Resonating Group Model: Three and Four Nucleons

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    The Effective Field Theory "without pions" at next-to-leading order is used to analyze universal bound state and scattering properties of the 3- and 4-nucleon system. Results of a variety of phase shift equivalent nuclear potentials are presented for bound state properties of 3H and 4He, and for the singlet S-wave 3He-neutron scattering length a_0(3He-n). The calculations are performed with the Refined Resonating Group Method and include a full treatment of the Coulomb interaction and the leading-order 3-nucleon interaction. The results compare favorably with data and values from AV18(+UIX) model calculations. A new correlation between a_0(3He-n) and the 3H binding energy is found. Furthermore, we confirm at next-to-leading order the correlations, already found at leading-order, between the 3H binding energy and the 3H charge radius, and the Tjon line. With the 3H binding energy as input, we get predictions of the Effective Field Theory "without pions" at next-to-leading order for the root mean square charge radius of 3H of (1.6\pm 0.2) fm, for the 4He binding energy of (28\pm 2.5) MeV, and for Re(a_0(3He-n)) of (7.5\pm 0.6)fm. Including the Coulomb interaction, the splitting in binding energy between 3H and 3He is found to be (0.66\pm 0.03) MeV. The discrepancy to data of (0.10\mp 0.03) MeV is model independently attributed to higher order charge independence breaking interactions. We also demonstrate that different results for the same observable stem from higher order effects, and carefully assess that numerical uncertainties are negligible. Our results demonstrate the convergence and usefulness of the pion-less theory at next-to-leading order in the 4He channel. We conclude that no 4-nucleon interaction is needed to renormalize the theory at next-to-leading order in the 4-nucleon sector.Comment: 24 pages revtex4, including 8 figures as .eps files embedded with includegraphicx, leading-order results added, calculations include the LO three-nucleon interaction explicitly, comment on Wigner bound added, minor modification
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