72 research outputs found

    Martensitic transition and magnetoresistance in a Cu-Al-Mn shape memory alloy. Influence of aging

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    We have studied the effect of ageing within the miscibility gap on the electric, magnetic and thermodynamic properties of a non-stoichiometric Heusler Cu-Al-Mn shape-memory alloy, which undergoes a martensitic transition from a bccbcc-based (β\beta-phase) towards a close-packed structure (MM-phase). Negative magnetoresistance which shows an almost linear dependence on the square of magnetization with different slopes in the MM- and β\beta-phases, was observed. This magnetoresistive effect has been associated with the existence of Mn-rich clusters with the Cu2_2AlMn-structure. The effect of an applied magnetic field on the martensitic transition has also been studied. The entropy change between the β\beta- and MM-phases shows negligible dependence on the magnetic field but it decreases significantly with annealing time within the miscibility gap. Such a decrease is due to the increasing amount of Cu2_2MnAl-rich domains that do not transform martensitically.Comment: 9 pages, 9 figures, accepted for publication in PR

    Disorder induced critical phenomena in magnetically glassy Cu-Al-Mn alloys

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    Measurements of magnetic hysteresis loops in Cu-Al-Mn alloys of different Mn content at low temperatures are presented. The loops are smooth and continuous above a certain temperature, but exhibit a magnetization discontinuity below that temperature. Scaling analysis suggest that this system displays a disorder induced phase transition line. Measurements allow to determine the critical exponents β=0.03±0.01\beta=0.03\pm 0.01 and βδ=0.4±0.1\beta \delta = 0.4 \pm 0.1 in agreement with those reported recently [Berger et al., Phys. Rev. Lett. {\bf 85}, 4176 (2000)]Comment: 4 pages, 5 figure

    TPEA PROJECT: MARITIME SPATIAL PLANNING IN THE GULF OF CADIZ

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    Maritime Spatial Planning (MSP) is coming to prominence as a new approach to the governance of the seas and oceans. It is taking on international importance as maritime nations exert greater control over their territorial waters and, in many cases, over much more extensive exclusive economic zones (Jay, 2010; Schaefer & Barale, 2011). This is in the interests of reversing the environmental degradation of the seas and facilitating the sustainable use of marine resources, both for traditional uses, such as fishing and navigation, and newer uses, such as renewable energy and mariculture (Douvere, 2008). MSP is being encouraged worldwide by inter-governmental bodies, NGOs, stakeholder organisations and marine scientists and managers (Agardy, 2010; De Santo, 2011; HELCOM & OSPAR, 2003), and a growing number of nations are drawing up spatial plans to regulate the use of their marine territories, in a way analogous to land-use planning

    Marine knowledge as a basis for Maritime Spatial Planning: TPEA Project

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    Comunicación oral presentada en SIEBM XVIII Simposio Ibérico de Biología MarinaThe Transboundary Planning in the European Atlantic (TPEA) project is developing as response to the European Commission (DG Mare’s) call for a Project on Maritime Spatial Planning in the Atlantic, including Celtic Sea and Bay of Biscay, in order to reflect the aim of the project, which is to deliver a commonly-agreed approach to cross-border MSP in the European Atlantic region.DG MARE - E

    Mapping child growth failure across low- and middle-income countries

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    Childhood malnutrition is associated with high morbidity and mortality globally1. Undernourished children are more likely to experience cognitive, physical, and metabolic developmental impairments that can lead to later cardiovascular disease, reduced intellectual ability and school attainment, and reduced economic productivity in adulthood2. Child growth failure (CGF), expressed as stunting, wasting, and underweight in children under five years of age (0�59 months), is a specific subset of undernutrition characterized by insufficient height or weight against age-specific growth reference standards3�5. The prevalence of stunting, wasting, or underweight in children under five is the proportion of children with a height-for-age, weight-for-height, or weight-for-age z-score, respectively, that is more than two standard deviations below the World Health Organization�s median growth reference standards for a healthy population6. Subnational estimates of CGF report substantial heterogeneity within countries, but are available primarily at the first administrative level (for example, states or provinces)7; the uneven geographical distribution of CGF has motivated further calls for assessments that can match the local scale of many public health programmes8. Building from our previous work mapping CGF in Africa9, here we provide the first, to our knowledge, mapped high-spatial-resolution estimates of CGF indicators from 2000 to 2017 across 105 low- and middle-income countries (LMICs), where 99 of affected children live1, aggregated to policy-relevant first and second (for example, districts or counties) administrative-level units and national levels. Despite remarkable declines over the study period, many LMICs remain far from the ambitious World Health Organization Global Nutrition Targets to reduce stunting by 40 and wasting to less than 5 by 2025. Large disparities in prevalence and progress exist across and within countries; our maps identify high-prevalence areas even within nations otherwise succeeding in reducing overall CGF prevalence. By highlighting where the highest-need populations reside, these geospatial estimates can support policy-makers in planning interventions that are adapted locally and in efficiently directing resources towards reducing CGF and its health implications. © 2020, The Author(s)

    Studies of azimuthal dihadron correlations in ultra-central PbPb collisions at=2.76 TeV

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