Microtraps for neutral atoms using superconducting structures in the critical state

Recently demonstrated superconducting atom-chips provide a platform for trapping atoms and coupling them to solid-state quantum systems. Controlling these devices requires a full understanding of the supercurrent distribution in the trapping structures. For type-II superconductors, this distribution is hysteretic in the critical state due to the partial penetration of the magnetic field in the thin superconducting film through pinned vortices. We report here an experimental observation of this memory effect. Our results are in good agreement with the redictions of the Bean model of the critical state without adjustable parameters. The memory effect allows to write and store permanent currents in micron-sized superconducting structures and paves the way towards new types of engineered trapping potentials.Comment: accepted in Phys. Rev.

Simultaneous supersingular reductions of CM elliptic curves

We study the simultaneous reductions at several supersingular primes of elliptic curves with complex multiplication. We show -- under additional congruence assumptions on the CM order -- that the reductions are surjective (and even become equidistributed) on the product of supersingular loci when the discriminant of the order becomes large. This variant of the equidistribution theorems of Duke and Cornut-Vatsal is an(other) application of the recent work of Einsiedler and Lindenstrauss on the classification of joinings of higher-rank diagonalizable actions.Comment: 46 pages. Revised according to the referee's comment

Sustainable Value: an application to the Swiss dairy farms of the mountainous area

The improvement of the sustainable performance of the agricultural sector is a priority of the Swiss agricultural policy. The sustainability of Swiss dairy farms located in the mountainous area might be critical as many of them show a weak performance in the use of their economic and/or social resources, and sometimes also of their environmental resources. An improvement of the sustainability of these farms prerequisites to better know on a large scale their sustainable performance and its determinants. For a representative sample of 480 dairy farms, we perform an assessment of their sustainable efficiency with the “sustainable value”, an approach to assess corporate sustainability based on the capital and opportunity cost theories. Using a linear regression, we analyze the determinants of the sustainable efficiency. The results show a tight positive relationship between sustainable performance and pure economic performance. The intensity of the use of intermediate consumptions is found to be the most important determinant of the sustainable efficiency. Farms with a high sustainable efficiency are those that use their intermediate consumptions in the most efficient way. The part of direct payments in the gross profit is shown to negatively affect the sustainable efficiency. The structural characteristics of the farms and the sociologic characteristics of the farmer managers are shown to hardly influence the sustainable efficiency.corporate sustainable performance, dairy farms, Switzerland, Farm Management, Livestock Production/Industries,

Experience from fifteen years of Malagasy lychee export campaigns

Lychee on the European markets. With approximately 2.8 Mt of annual global production, lychee constitutes a minor fruit in terms of production. The world production is mainly located in the northern hemisphere (95%). However, most of the quantity exported to the EU comes from the southern hemisphere. In this context, with its 100,000 t of annual production, Madagascar is ranked fourth in the producing world and first in the southern hemisphere producing countries. This rank is due to the fact that supplies in the EU are seasonal and mainly concentrated during the end of the year holiday season. This market can only be supplied in quantity by the Malagasy lychee because of its earlier date of harvest in the Indian Ocean. The lychee industry in Madagascar. Lychee cultivation in Madagascar dates from the early twentieth century. It is primarily grown in wet tropical lowlands of the island with some production in areas with a subtropical climate with dry and cool winters. The stand is not structured into orchards. Therefore, the volumes currently exported are based on a stand established by a multitude of small producers. The characteristics of Malagasy lychee export and the consequences of the production context on export are analyzed. Changes in European legislation on lychee importation. The regulatory changes since 1987 and the commercial developments since 1994 are reviewed by analyzing the resulting effects on the Malagasy lychee exports. Learning experience from fifteen years of Malagasy lychee export campaigns. Data on Malagasy lychee export campaigns from 1996 to 2012 and the history of the changes in volumes exported allow a close analysis of the factors affecting the Malagasy lychee industry. Success factors of the Malagasy lychee exports. These factors are related to securing market position and to the components of a marketing campaign (supply date to the European market, exported volumes and competition from produce from other countries). Conclusions. Lychees from Madagascar, although marketed for a very brief period, currently occupy the first rank on the European markets and have managed, through the development of transport logistics using very large-capacity cargoes, to eliminate all competition. However, this sector is mainly structured downstream and its production, which comprises a network of 30,000 small producers, has been neglected. This lack of intervention (boosting of production, improving crop management, etc.) upstream of the chain does not support sustaining the industry in the medium term. (Résumé d'auteur

Maximum probability domains from Quantum Monte Carlo Calculations

International audienceAlthough it would be tempting to associate the Lewis structures to the maxima of the squared wave function |Psi|2, we prefer in this paper the use of domains of the three-dimensional space, which maximize the probability of containing opposite-spin electron pairs. We find for simple systems (CH4, H2O, Ne, N2, C2H2) domains comparable to those obtained with the electron localization function (ELF) or by localizing molecular orbitals. The different domains we define can overlap, and this gives an interesting physical picture of the floppiness of CH5+ and of the symmetric hydrogen bond in FHF-. The presence of multiple solutions has an analogy with resonant structures, as shown in the trans-bent structure of Si2H2. Correlated wave functions were used (MCSCF or Slater-Jastrow) in the Variational Quantum Monte Carlo framework

Detection of Capsular Polysaccharide in Serum for the Diagnosis of Pneumococcal Pneumonia: Clinical and Experimental Evaluation

To improve diagnostic options for pneumococcal pneumonia, an ELISA system was developed that can detect ⩽6 ng/ml capsular polysaccharide in serum. The test waslimited to 39 serotypes causing >95% of pneumococcal infections. In clinical evaluation the test identified 14 of 15 cases (missing one serotype not included). No false-positive reaction occurred. However, the duration and level of antigenemia were variable (⩾500-2.5 ng/ml) and seemed not to depend solely on the severity of infection. Therefore, the question of whether the extent of antigenemia was determined by a serotype-dependent variation in the elimination rates of polysaccharides was investigated. Clearance rates for 12 serotypes varied in rabbits and rats by a factor of >250. This remarkable variability appeared to affect the extent of clinical antigenemia. Thus, only very sensitive systems can detect circulating antigen from rapidly cleared polysaccharide serotypes. Furthermore, the question arises whether slow polysaccharide clearance contributes to the virulence of some pneumococcal serotype

Demonstrating the decoupling regime of the electron-phonon interaction in a quantum dot using chirped optical excitation

Excitation of a semiconductor quantum dot with a chirped laser pulse allows excitons to be created by rapid adiabatic passage. In quantum dots this process can be greatly hindered by the coupling to phonons. Here we add a high chirp rate to ultra-short laser pulses and use these pulses to excite a single quantum dot. We demonstrate that we enter a regime where the exciton-phonon coupling is effective for small pulse areas, while for higher pulse areas a decoupling of the exciton from the phonons occurs. We thus discover a reappearance of rapid adiabatic passage, in analogy to the predicted reappearance of Rabi rotations at high pulse areas. The measured results are in good agreement with theoretical calculations.Comment: Main manuscript 5 pages and 4 figures, Supplementary Information 5 pages and 3 figures, submitted to PR

Adult age differences in prospective memory in the laboratory : Are they related to higher stress levels in the elderly?

Peer reviewedPublisher PD