416 research outputs found
How the implementation of the landing obligation was weakened
This chapter covers the development of provisions and exemptions to the Landing Obligation in the years following the adoption of the Common Fisheries Policy in December 2013. It focuses on the processes leading to certain changes in Article 15, the development of discard plans, and describes reasons for the slow implementation of the Landing Obligation. It provides further insight into why the intention of the objective of the discard ban, the reduction of unwanted catches, has not yet been achieved to its maximum possible extent
Aluminium content of spanish infant formula
Aluminium toxicity has been relatively well documented in infants with impaired renal
function and premature neonates.
The aims of this study were to analyse the concentration of aluminium in the majority of
infant formulae sold commercially in Spain, to determine the influence of aluminium
content in the tap water in reconstituted powder formulae and to estimate the theoretical
toxic aluminium intake in comparison with the PTWI, and lastly, to discuss the possible
interactions of certain essential trace elements added to formulation with aluminium
according to type or main protein based infant formula.
A total of 82 different infant formulae from 9 different manufacturers were studied.
Sample digestion was simulated in a closed acid-decomposition microwave system.
Aluminium concentration was determined by atomic absorption spectrophotometry with
graphite furnace.
In general, the infant formulae studied provide an aluminium level higher than that found
in human milk, especially in the case of soya, preterm or hydrolysed casein-based
formulae.
Standard formulae provide lower aluminium intakes amounting to about 4 % PTWI.
Specialised and preterm formulae result in moderate intake (11 â 12 % and 8 â 10 %
PTWI, respectively). Soya formulae contribute the highest intake (15 % PTWI).
Aluminium exposure from drinking water used for powder formula reconstitution is not
considered a clear potential risk.
In accordance with the present state of knowledge about aluminium toxicity, it seems
prudent to call for continued efforts to standardise routine quality control and reduce
aluminium levels in infant formula as well as to keep the aluminium concentration under
300 g l-1 for all infant formulae, most specifically those formulae for premature and low
birth neonates
Proton acceleration enhanced by a plasma jet in expanding foils undergoing relativistic transparency
Ion acceleration driven by the interaction of an ultraintense (2x10^20 Wcm^-2) laser pulse with an ultrathin (40nm) foil target is experimentally and numerically investigated. Protons accelerated by sheath fields and via laser radiation pressure are angularly separated and identified based on their directionality and signature features (e.g. transverse instabilities) in the measured spatial-intensity distribution. A low divergence, high energy proton component is also detected when the heated target electrons expand and the target becomes relativistically transparent during the interaction. 2D and 3D particle-in-cell (PIC) simulations indicate that under these conditions a plasma jet is formed at the target rear, supported by a self-generated azimuthal magnetic field, which extends into the expanded layer of sheath-accelerated protons. Electrons trapped within this jet are directly accelerated to super-thermal energies by the portion of the laser pulse transmitted through the target. The resulting streaming of the electrons into the ion layers enhances the energy of protons in the vicinity of the jet. Through the addition of a controlled prepulse, the maximum energy of these protons is demonstrated experimentally and numerically to be sensitive to the picosecond rising edge prole of the laser pulse
Ion acceleration and plasma jet formation in ultra-thin foils undergoing expansion and relativistic transparency
At sufficiently high laser intensities, the rapid heating to relativistic velocities and resulting decompression of plasma electrons in an ultra-thin target foil can result in the target becoming relativistically transparent to the laser light during the interaction. Ion acceleration in this regime is strongly affected by the transition from an opaque to a relativistically transparent plasma. By spatially resolving the laser-accelerated proton beam at near-normal laser incidence and at an incidence angle of 30°, we identify characteristic features both experimentally and in particle-in-cell simulations which are consistent with the onset of three distinct ion acceleration mechanisms: sheath acceleration; radiation pressure acceleration; and transparency-enhanced acceleration. The latter mechanism occurs late in the interaction and is mediated by the formation of a plasma jet extending into the expanding ion population. The effect of laser incident angle on the plasma jet is explored
Re-structuring of marine communities exposed to environmental change: a global study on the interactive effects of species and functional richness
Species richness is the most commonly used but controversial biodiversity metric in studies on aspects of community stability such as structural composition or productivity. The apparent ambiguity of theoretical and experimental findings may in part be due to experimental shortcomings and/or heterogeneity of scales and methods in earlier studies. This has led to an urgent call for improved and more realistic experiments. In a series of experiments replicated at a global scale we translocated several hundred marine hard bottom communities to new environments simulating a rapid but moderate environmental change. Subsequently, we measured their rate of compositional change (re-structuring) which in the great majority of cases represented a compositional convergence towards local communities. Re-structuring is driven by mortality of community components (original species) and establishment of new species in the changed environmental context. The rate of this re-structuring was then related to various system properties. We show that availability of free substratum relates negatively while taxon richness relates positively to structural persistence (i.e., no or slow re-structuring). Thus, when faced with environmental change, taxon-rich communities retain their original composition longer than taxon-poor communities. The effect of taxon richness, however, interacts with another aspect of diversity, functional richness. Indeed, taxon richness relates positively to persistence in functionally depauperate communities, but not in functionally diverse communities. The interaction between taxonomic and functional diversity with regard to the behaviour of communities exposed to environmental stress may help understand some of the seemingly contrasting findings of past research.Mercator Stiftung via GAMEPostprint4,41
Connectivity and resilience of coral reef metapopulations in marine protected areas : matching empirical efforts to predictive needs
© 2009 The Authors. This is an open-access article distributed under the terms of the Creative Commons Attribution Noncommercial License. The definitive version was published in Coral Reefs 28 (2009): 327-337, doi:10.1007/s00338-009-0466-z.Design and decision-making for marine protected areas (MPAs) on coral reefs require prediction of MPA effects with population models. Modeling of MPAs has shown how the persistence of metapopulations in systems of MPAs depends on the size and spacing of MPAs, and levels of fishing outside the MPAs. However, the pattern of demographic connectivity produced by larval dispersal is a key uncertainty in those modeling studies. The information required to assess population persistence is a dispersal matrix containing the fraction of larvae traveling to each location from each location, not just the current number of larvae exchanged among locations. Recent metapopulation modeling research with hypothetical dispersal matrices has shown how the spatial scale of dispersal, degree of advection versus diffusion, total larval output, and temporal and spatial variability in dispersal influence population persistence. Recent empirical studies using population genetics, parentage analysis, and geochemical and artificial marks in calcified structures have improved the understanding of dispersal. However, many such studies report current self-recruitment (locally produced settlement/settlement from elsewhere), which is not as directly useful as local retention (locally produced settlement/total locally released), which is a component of the dispersal matrix. Modeling of biophysical circulation with larval particle tracking can provide the required elements of dispersal matrices and assess their sensitivity to flows and larval behavior, but it requires more assumptions than direct empirical methods. To make rapid progress in understanding the scales and patterns of connectivity, greater communication between empiricists and population modelers will be needed. Empiricists need to focus more on identifying the characteristics of the dispersal matrix, while population modelers need to track and assimilate evolving empirical results.Work by CB Paris was supported by the
National Science Foundation grant NSF-OCE 0550732. Work by
M-A Coffroth and SR Thorrold was supported by the National Science
Foundation grant NSF-OCE 0424688. Work by TL Shearer was
supported by an International Cooperative Biodiversity Group grant
R21 TW006662-01 from the Fogarty International Center at the
National Institutes of Health
Factors confounding the assessment of reflection: a critical review
BACKGROUND: Reflection on experience is an increasingly critical part of professional development and lifelong learning. There is, however, continuing uncertainty about how best to put principle into practice, particularly as regards assessment. This article explores those uncertainties in order to find practical ways of assessing reflection. DISCUSSION: We critically review four problems: 1. Inconsistent definitions of reflection; 2. Lack of standards to determine (in)adequate reflection; 3. Factors that complicate assessment; 4. Internal and external contextual factors affecting the assessment of reflection. SUMMARY: To address the problem of inconsistency, we identified processes that were common to a number of widely quoted theories and synthesised a model, which yielded six indicators that could be used in assessment instruments. We arrived at the conclusion that, until further progress has been made in defining standards, assessment must depend on developing and communicating local consensus between stakeholders (students, practitioners, teachers, supervisors, curriculum developers) about what is expected in exercises and formal tests. Major factors that complicate assessment are the subjective nature of reflection's content and the dependency on descriptions by persons being assessed about their reflection process, without any objective means of verification. To counter these validity threats, we suggest that assessment should focus on generic process skills rather than the subjective content of reflection and where possible to consider objective information about the triggering situation to verify described reflections. Finally, internal and external contextual factors such as motivation, instruction, character of assessment (formative or summative) and the ability of individual learning environments to stimulate reflection should be considered
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