Magnetic nanoparticles as efficient bulk pinning centers in type-II superconductors

Enhancement of flux pinning by magnetic nanoparticles embedded into the bulk of type-2 superconductor is studied both theoretically and experimentally. Magnetic part of the pinning force associated with the interaction between a spherical magnetic inclusion and an Abrikosov vortex was calculated in the London approximation. Calculations are supported by the experimental results obtained on sonochemically modified MgB2 superconductor with embedded magnetic Fe2O3 nanoparticles and compared to MgB2 with nonmagnetic Mo2O5 pinning centers of similar concentration and particle size distribution. It is shown that ferromagnetic nanoparticles result in a considerable enhancement of vortex pinning in large-kappa type-2 superconductors.Comment: PDF, 14 page

2-я Международная конференция «Высокочистые материалы: получение, применения, свойства»

17–20 сентября 2013 года в Харькове проходила 2-я Международная конференция «Высокочистые материалы: получение, применения, свойства», посвященная памяти академика НАН Украины Владимира Михайловича Ажажи. В организации Конференции приняли участие: Национальная академия наук Украины, Отделение ядерной физики и энергетики НАНУ, Национальный научный центр «Харьковский физико-технический институт», Харьковский национальный университет им. В.Н. Каразина. В работе Конференции приняло участие более 50 человек

Superfluid fraction in an interacting spatially modulated Bose-Einstein condensate

At zero temperature, a Galilean-invariant Bose fluid is expected to be fully superfluid. Here we investigate theoretically and experimentally the quenching of the superfluid density of a dilute Bose-Einstein condensate due to the breaking of translational (and thus Galilean) invariance by an external 1D periodic potential. Both Leggett's bound fixed by the knowledge of the total density and the anisotropy of the sound velocity provide a consistent determination of the superfluid fraction. The use of a large-period lattice emphasizes the important role of two-body interactions on superfluidity

Evaluation, contrôle et prévention du risque de transmission du virus influenza aviaire à l'homme

Since mid-december 2003, an epizootic of highly pathogenic avian influenza (type A, sub-type H5N1) occurs in eastern and south-eastern Asia. This epizootic is historically unprecedented in its virulence, geographical spread, and economic consequences for the agricultural sector. Implications for human health were registered in Vietnam and in Thailand. This paper summarizes the current knowledge about the risk evaluation of the transmission of avian influenza virus to humans. The current asian epizootic has highlighted the key role of global health information systems and also the need for exhaustive notification of human and animal cases. It reinforces the concept of veterinary public health

Insight from PREFACE & AWA on Tropical Atlantic Tuna ecology and effects on western African fisheries economies

International audienc

ENSO impact on northwest African upwelling

One of the most robust ENSO teleconnections is that linking SST anomalies in the equatorial Pacific and Tropical North Atlantic (TNA) in boreal spring. While the role played by the wind-evaporation-SST (WES) feedback in maintaining the ENSO-related SST anomalies over the TNA is well understood, many questions remain open about the signature of this ENSO teleconnection on the northwest African upwelling system and its role for the further response during the spring season along the whole TNA. This issue is analyzed here in both observations and CGCM models with different nominal resolution (CMIP6 HighResMIP simulations). In particular, the relevance of the mean state variability in the tropical Atlantic for modulating the northwest African upwelling response to ENSO has been assessed in depth. Furthermore, and considering the exceptional ecological importance of this upwelling area, the ENSO-related influence on the spatio-temporal variability of round sardinella (the dominant fish species in terms of abundance) has been also analyzed. To this aim, an end-to-end strategy which combines models of physics (hydrodynamic), lower trophic levels (nutrient-plankton) and upper trophic levels (sardinella), is used. All these analyses highlight from both climate and ecological perspectives, the relevance of better understanding the ENSO-northwest African upwelling teleconnection.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech