Transformations between HCLP and PCSP

We present a general methodology for transforming between HCLP and PCSP in both directions. HCLP and PCSP each have advantages when modelling problems, and each have advantages when implementing models and solving them. Using the work presented in this paper, the appropriate paradigm can be used for each of these steps, with a meaning-preserving transformation in between if necessary

A process algebra for synchronous concurrent constraint programming

Concurrent constraint programming is classically based on asynchronous communication via a shared store. This paper presents new version of the ask and tell primitives which features synchronicity. Our approach is based on the idea of telling new information just in the case that a concurrently running process is asking for it. An operational and an algebraic semantics are defined. The algebraic semantics is proved to be sound and complete with respect to a compositional operational semantics which is also presented in the paper

Cardinality heterogeneities in Web service composition: Issues and solutions

Data exchanges between Web services engaged in a composition raise several heterogeneities. In this paper, we address the problem of data cardinality heterogeneity in a composition. Firstly, we build a theoretical framework to describe different aspects of Web services that relate to data cardinality, and secondly, we solve this problem by developing a solution for cardinality mediation based on constraint logic programming

La stabilité des éléments super-lourds sondée par des mesures de temps de fission

Une technique originale fondée sur la mesure de temps de réactions nucléaires a été développée au laboratoire du Grand Accélérateur National d'Ions Lourds à Caen (GANIL) pour mettre en évidence l'existence de noyaux d'éléments super-lourds - de masse très supérieure à ce qui existe sur terre à l'état naturel - et pour sonder leur stabilité

Picoheterotroph (Bacteria and Archaea) biomass distribution in the global ocean

We compiled a database of 39 766 data points consisting of flow cytometric and microscopical measurements of picoheterotroph abundance, including both Bacteria and Archaea. After gridding with 1° spacing, the database covers 1.3% of the ocean surface. There are data covering all ocean basins and depths except the Southern Hemisphere below 350m or from April until June. The average picoheterotroph biomass is 3.9 ± 3.6 µg Cl-1 with a 20-fold decrease between the surface and the deep sea. We estimate a total ocean inventory of about 1.3 × 1029 picoheterotroph cells. Surprisingly, the abundance in the coastal regions is the same as at the same depths in the open ocean. Using an average of published open ocean measurements for the conversion from abundance to carbon biomass of 9.1 fg cell-1, we calculate a picoheterotroph carbon inventory of about 1.2 Pg C. The main source of uncertainty in this inventory is the conversion factor from abundance to biomass. Picoheterotroph biomass is ? 2 times higher in the tropics than in the polar oceans

A neglected disease of humans: a new focus of visceral leishmaniasis in Bakool, Somalia.

Visceral leishmaniasis (VL) was observed in children in Bakool region, Somalia, an area where VL has not been reported before. We describe the extent of the problem in this war- and famine-stricken area. A retrospective analysis was done of all cases admitted to a VL treatment centre between July 2000 and August 2001. Patients with longstanding fever, splenomegaly and a positive direct agglutination test (DAT; titre > 1:3200) were treated as suspected VL cases. A rapid epidemiological and entomological assessment was performed in the area. Species identification was attempted from blood samples by polymerase chain reaction-restriction fragment length polymorphism analysis of cysteine proteinase B genes. In 1 year, 230 serologically-positive cases were diagnosed as VL, and response to therapy was good in 91.6% of the 225 treated with sodium stibogluconate. Parasitological confirmation was attempted and obtained in 2 cases. Parasites were found to be most similar to Sudanese and Ethiopian reference strains of the Leishmania donovani complex. In a serological survey of 161 healthy displaced persons, 15% were positive by the leishmanin skin test and 3 (2%) were positive by the DAT. The sandfly captures showed Phlebotomus martini and P. vansomerenae. VL seems to be a longstanding and serious health problem in Bakool region. Food insecurity might have contributed to the emergence and detection of VL in this area

Measurement of energy and angular distributions of secondary ions in the sputtering of gold by swift Au-n clusters: Study of emission mechanisms

Energy and angular distributions of negative ions (Au–, Au2-, Au3-, and Au5-) emitted from gold target bombarded by Au, Au4, and Au9 projectiles at 200 keV/atom were measured with a multipixel position sensitive detector. The angular distributions are symmetrical with respect to the normal to the target surface and forward peaked. They depend on the type of emitted ions, on the emission energy, and on the projectile size. More forward directed emission is observed with Au9 projectiles. The secondary ion energy distributions obtained with Au and Au4 projectiles are well reproduced by a sum of linear collision cascades and thermal spike processes. However, in the case of Au9 projectiles the energy distributions are better described by using a simple spike model with two different average temperature regimes: the first one corresponds to high emission energy occurring in the early stage of the whole process, and the second to the low energy component

Spin-polarized tunneling spectroscopy in tunnel junctions with half-metallic electrodes

We have studied the magnetoresistance (TMR) of tunnel junctions with electrodes of La2/3Sr1/3MnO3 and we show how the variation of the conductance and TMR with the bias voltage can be exploited to obtain a precise information on the spin and energy dependence of the density of states. Our analysis leads to a quantitative description of the band structure of La2/3Sr1/3MnO3 and allows the determination of the gap delta between the Fermi level and the bottom of the t2g minority spin band, in good agreement with data from spin-polarized inverse photoemission experiments. This shows the potential of magnetic tunnel junctions with half-metallic electrodes for spin-resolved spectroscopic studies.Comment: To appear in Physical Review Letter