711 research outputs found

    Domain configuration and magnetization switching in arrays of permalloy nanostripes

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    The proximity effect in the collective behavior of arrays of magnetic nanostripes is currently a subject of intensive research. The imperative of reducing the size and distances between elements in order to achieve higher storage capacity, faster access to the information as well as low energy consumption, brings consequences about the isolated behavior of the elements and devices. Parallel to each other permalloy nanostripes with high aspect ratio have been prepared by the nanolithography technique. The evolution of the closure domains and the magnetization direction in individual nanostructures has been imaged under applied magnetic fields using Variable Field Magnetic Force Microscopy. Moreover, the magnetostatic interactions between neighboring elements and the proximity effects in arrays of such nanostructures have been quantitatively analyzed by Magnetic Force Microscopy and micromagnetic simulations. The agreement between simulations and the experimental results allows us to conclude the relevance of those interactions depending on the geometry characteristics. In particular, results suggest that the magnetostatic coupling between adjacent nanostripes vanishes for separation distances higher than 500 nm

    EU External Relations: Exclusive Competence Revisited

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    This Article will focus on the question of exclusive competence in the field of EU external relations, especially in the light of recent developments. After a brief discussion on the origins and development of exclusive competence, a distinction will be made between common commercial policy, which has traditionally been the most important area of an explicit “a priori” exclusive competence, and what is often called an implicit exclusive competence, which, as it is today based on some general criteria enshrined in TFEU Article 3(2), may be called “supervening” exclusive competence. With regard to both categories, the main focus will be on recent developments, notably the impact of the Treaty of Lisbon, which introduced the TFEU and its Articles 2 and 3, as well as the case law of the European Court of Justice (“ECJ” or the “Court”) following the entry into force of the Treaty of Lisbon, on December 1, 2009

    Differences in behavioural traits among native and introduced colonies of an invasive ant

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    Identifying the factors that promote the success of biological invasions is a key pursuit in ecology. To date, the link between animal personality and invasiveness has rarely been studied. Here, we examined in the laboratory how Argentine ant populations from the species' native and introduced ranges differed in a suite of behaviours related to species interactions and the use of space. We found correlations among specific behavioural traits that defined an explorative-aggressive syndrome. The Main "European" supercolony (introduced range) more readily explored novel environments, displayed more aggression, detected food resources more quickly, and occupied more space than the Catalonian supercolony (introduced range) and two other Argentine supercolonies (native range). The two native supercolonies also differed in their personalities; one harbouring the less invasive personality, while the other is intermediate between the two introduced supercolonies. Therefore, instead of a binary pattern, Argentine ant supercolonies display a behavioural continuum that is independent on their geographic origin (native/introduced ranges). Our results also suggest that variability in personality traits is correlated to differences in the ecological success of Argentine ant colonies. Differences in group personalities may facilitate the persistence and invasion of animals under novel selective pressures by promoting adaptive behaviours. We stress that the concept of animal personality should be taken into account when elucidating the mechanisms of invasiveness

    Comprehensive transient-state study for CARMENES-NIR high thermal stability

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    CARMENES has been proposed as a next-generation instrument for the 3.5m Calar Alto Telescope. Its objective is finding habitable exoplanets around M dwarfs through radial velocity measurements (m/s level) in the near-infrared. Consequently, the NIR spectrograph is highly constraint regarding thermal/mechanical requirements. As a first approach, the thermal stability has been limited to \pm 0.01K (within year period) over a working temperature of 243K. This can be achieved by means of several temperature-controlled rooms. The options considered to minimise the complexity of the thermal design are here presented, as well as the transient-state thermal analyses realised to make the best choice

    Field induced magnetic transition and metastability in Co substituted Mn2SbMn_{2}Sb

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    A detailed investigation of first order ferrimagnetic (FRI) to antiferromagnetic (AFM) transition in Co (15%) doped Mn2SbMn_2Sb is carried out. These measurements demonstrate anomalous thermomagnetic irreversibility and glass-like frozen FRI phase at low temperatures. The irreversibility arising between the supercooling and superheating spinodals is distinguised in an ingenious way from the irreversibility arising due to kinetic arrest. Field annealing measurements shows reentrant FRI-AFM-FRI transition with increasing temperature. These measurements also show that kinetic arrest band and supercooling band are anitcorrelated i.e regions which are kinetically arrested at higher temperature have lower supercooling temperature and vice versa.Comment: 10 pages, 8 figure

    Settling fluxes and sediment accumulation rates by the combined use of sediment traps and sediment cores in Tema Harbour (Ghana)

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    Settling fluxes and sediment accumulation rates in coastal Tema Harbour (Ghana) were investigated by the combined analyses of results in sediment traps and sediment cores. Sediment traps were deployed at 5 stations within the Tema Harbour at two sampling depths and were retrieved every two weeks till the end of 12 weeks to estimate the Settling Fluxes (SFs). Four sediment cores from the harbour were analysed for their radioactivity (7Be, 234Th, 210Pb, 212Pb, 226Ra, 40K and 137Cs) profiles to quantify Sediment Accumulation Rates (SARs). The sediment cores exhibited variable bulk density profiles, indicating highly dynamic and non-steady sedimentation conditions. 7Be-derived gross-estimates of very recent SARs using the constant flux-constant sedimentation (CF-CS) model were in the range of 2.5–9.0 g·cm− 2·y− 1. These values were much lower than the estimated average SFs (15.2–53.8 g·cm− 2·y− 1), indicating sediment resuspension plays an important role. On a decadal time scale, conventional 210Pb sediment dating models did not allow any estimation of SARs in the Tema Harbour. Thus, the 210Pb-based TERESA model was applied to depict a reliable scenario for sedimentation with time-averaged SARs in the range of 1.4–3.0 g·cm− 2·y− 1 and fluxes of matter contributed by the marine inflow and local sources. Sediment accretion rates of 1.7–3 cm·y− 1 were also inferred, which may pose a moderate problem of sustainability for the Tema Harbour. This study reveals how the geochemical behaviour of different radionuclides with Gamma spectrometry in the marine environment can be used to obtain reliable information on the complex dynamics of Suspended Particulate Matter (SPM), even in a very disturbed and anthropic environment as a coastal harbour area where (1) conventional 210Pb-based dating methods fail and (2) the use of sediment traps and 234Th and 7Be profiles in sediment cores show serious constraints.University of Ghana UGFD/7/2012-2013/00

    Multidimensional emotional disorders inventory: Reliability and validity in a Spanish clinical sample

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    Background. The categorical approach to diagnosing mental disorders has been criticized for a number of reasons (e.g., high rates of comorbidity; larger number of diagnostic categories and combination). Diverse alternatives have been proposed using a hybrid or totally dimensional perspective. Despite the evidence supporting use of the Multidimensional Emotional Disorders Inventory (MEDI) for assessing the transdiagnostic dimensions of Emotional Disorders using a dimensional-categorical hybrid approach, no data exist on Spanish clinical samples. The present study explores the validity and reliability of the 49-item MEDI in a clinical sample and provides data for its use. Methods. A total of 280 outpatients with emotional disorders attended in different Spanish public Mental Health Units in Spain filled out all questionnaires during the assessment phase and the MEDI again one week after. The instruments used evaluate four main constructs: personality, mood, anxiety and avoidance. Results. The nine original factors were confirmed and showed adequate reliability (α: 0.66–0.91) and stability (r = 0.76–0.87). No differences in mean scores by sex were presented in any subscale (p ≄ .07). The MEDI subscales correlated significantly with the scales of each of the selected constructs (0.45 < r < 0.76). Limitations. The main limitations of this study were the limited sample size and not being able to count on MEDI scores post-transdiagnostic intervention. Conclusions. The MEDI demonstrates adequate reliability and validity. It allows to assess diverse symptoms efficiently, thus being of interest for clinical studies and practice

    Transfer of Cd, Pb, Ra and U from Phosphogypsum Amended Soils to Tomato Plants

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    About 170 million tons of phosphogypsum (PG) are annually generated worldwide as a by-product of phosphoric acid factories. Agricultural uses of PG could become the main sink for this waste, which usually contains significant radionuclide (from the 238U-series) and toxic metals concentrations. To study PG effects on pollutant uptake by crops, a completely randomised greenhouse experiment was carried out growing Lycopersicum esculentum Mill L. on a reclaimed marsh soil amended with three PG rates (treatments), corresponding to zero (control without PG application), one, three and ten times the typical PG rates used in SW Spain (20 Mg ha−1). The concentrations of Cd, Pb, U (by inductively coupled plasma mass spectroscopy) and 226Ra and 210Po (by Îł-spectrometry and α-counting, respectively) were determined in soil, vegetal tissue and draining water. Cadmium concentrations in fruit increased with PG rates, reaching 44 ± 7 ÎŒg kg−1 formula weight with ten PG rates (being 50 ÎŒg kg−1 the maximum allowed concentration by EC 1881/2006 regulation). Cd transfer factors in non-edible parts were as high as 4.8 ± 0.5 (dry weight (d.w.)), two orders of magnitude higher than values found for lead, lead, uranium and radium concentrations in fruit remained below the corresponding detection limits—0.5 and 0.25 mg kg−1 and 0.6 mBq kg−1, respectively (in a d.w. basis). 238U (up to 7 ÎŒg kg−1 d.w.) and 210Po (up to 0.74 Bq kg−1 d.w.) could be measured in some fruit samples by α-spectrometry. Overall, the concentrations of these metals and radionuclides in the draining water accounted for less than 1% of the amount applied with PGJunta de AndalucĂ­a IFAPA-C03

    ICTD Work, Plus mFeel : improving communication in resource-poor settings

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    This issue's Works-In-Progress department has four entries related to the issue's theme, Information and Communication Technologies for Development (ICTD). They are “Sustainable ICT in Agricultural Value Chains”, “Measuring Social Inclusion in Primary Schools”, “An Architecture for Green Mobile Computation”, and “Improving Communication in Resource-Poor Settings”. A fifth entry, “mFeel: An Affective Mobile System”, covers the mFeel mobile system, which combines context awareness with affective and cognitive techniques
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