Sharp asymptotics for the partition function of some continuous-time directed polymers

This paper is concerned with two related types of directed polymers in a random medium. The first one is a d-dimensional Brownian motion living in a random environment which is Brownian in time and homogeneous in space. The second is a continuous-time random walk on the lattice Z^d, in a random environment with similar properties as in continuous space. The case of a space-time white noise environment can be acheived in this second setting. By means of some Gaussian tools, we estimate the free energy of these models at low temperature, and give some further information on the strong disorder regime of the objects under consideration.Comment: 29

Outside Italy:Pasolini’s Transnational Visions of the Sacred and Tradition

In the 1960s and 1970s, Pier Paolo Pasolini described a rapidly changing world, expressing a new poetics that can be considered transnational. I will use different examples – beginning with Pasolini’s Indian travelogues – to show how his initial devotion to Italian millenary traditions and peasant cultures finally led to an open vision and understanding of human behaviors and mores beyond any national boundary

Whole genome sequences of two Salmonella Dublin strains harbour viaA, viaB and ompB loci of the Vi antigen

Here we report the genome sequence of two Salmonella enterica serovar Dublin, 03EB8736SAL and 03EB8994SAL, isolated from raw milk cheese and filter of milk respectively. Analysis of draft genomes of the two isolates reveals the presence of viaA, viaB and ompB loci of the Vi capsular polysaccharide antigen (Vi antigen)

In Vivo Characterization of Thoracolumbar Range of Motion in Healthy Populations

The long term objective of this research was to investigate thoracolumbar mobility in vivo and develop a method that allows for the comparison of motion data between in vivo and cadaveric models. Many research studies have investigated in vivo motion and the effects of aging on the lumbar spine, but little has been done for the thoracic and thoracolumbar spine. The thoracolumbar spine is commonly affected by adult deformities, resulting in chronic back pain, osteoarthritis, and osteoporosis. The goal of treating these deformities is to return the spine to native condition. In order to accomplish this, research must be conducted on how the native thoracolumbar spine functions in the representative patient population. The first objective of this study was to quantify the effect of aging on the thoracolumbar spine. The in vivo thoracolumbar mobility of healthy adolescents and healthy older adults was compared to investigate how the non-pathologic thoracolumbar spine changes with age. The study results quantified that the healthy adolescent spine has significantly more motion than the healthy older adult spine in three modes of bending. The second study objective was to develop a method that allows for the comparison of spinal motion data in different physiological models and to frame in vivo motion data in a way that is meaningful to clinicians. The analysis technique developed allowed for clinical parameters to be investigated in an in vivo motion model that previously was difficult to measure. The results from this work found that the healthy adolescent spine is more mobile than the healthy older adult spine. The next steps are to directly compare cadaveric and in vivo spinal motion models for healthy older adults. It is important to be able to compare the data from these two models, particularly when designing medical devices. Pediatric and adolescent spinal devices are tested on older adult cadavers. If pediatric and adolescent in vivo motion cannot be compare to older adult cadaveric motion, the use of older adult cadavers cannot be validated

Relation between composition, microstructure and oxidation in iron aluminides

The relation between chemical composition, microstructure and oxidation properties has been investigated on various FeAl based alloys, the aim being to induce changes in the microstructure of the compound by selective oxidation of aluminium. Oxidation kinetics that was evaluated on bulk specimens showed that, due to fast diffusion in the alloys, no composition gradient is formed during the aluminium selective oxidation. Accordingly, significant aluminium depletion in the compound could be observed in the thinnest part of oxidised wedge-shape specimens. Another way to obtain samples of variable aluminium content was to prepare diffusion couples with one aluminide and pure iron as end members. These latter specimens have been characterised using electron microscopy and first results of oxidation experiments are presented

3D atom probe tomography of swift heavy ion irradiated multilayers

International audienceNanometer scale layered systems are well suited to investigate atomic transport processes induced by high-energy electronic excitations in materials, through the characterization of the interface transformation. In this study, we used the atom probe technique to determine the distribution of the different elements in an (amorphous-Fe$_2$Tb 5 nm/hcp-Co 3 nm)$_{20}$ multilayer before and after irradiation with Pb ions in the electronic stopping power regime. Atom probe tomography is based on reconstruction of a small volume of a sharp tip evaporated by field effect. It has unique capabilities to characterize internal interfaces and layer chemistry with sub-nanometer scale resolution in three dimensions. Depth composition profiles and 3D element mapping have been determined, evidencing for asymetric interfaces in the as-deposited sample, and very efficient Fe-Co intermixing after irradiation at the fluence $7\times10^{12}$ ion cm$^{-2}$. Estimation of effective atomic diffusion coefficients after irradiation suggests that mixing results from interdiffusion in a molten track across the interface in agreement with the thermal spike model

Best-Fit Ellipsoids of Atom-Probe Tomographic Data to Study Coalescence of Gamma Prime (L1_2) Precipitates in Ni-Al-Cr

An algorithm is presented to fit precipitates in atom probe tomographic data sets as equivalent ellipsoids. Unlike previous techniques, which measure only the radius of gyration, these ellipsoids retain the moments of inertia and principle axes of the original precipitate, preserving crystallographic orientational information. The algorithm is applied to study interconnected gamma prime precipitates (L1_2) in the Gamma-matrix (FCC) of a Ni-Al-Cr alloy. The precipitates are found to coagulate along -type directions.Comment: Accepted for publication in Scripta Materialia, added information about local magnification effect

Genetic Diversity of Salmonella Derby from the Poultry Sector in Europe

International audienceSalmonella Derby (S. Derby) is emerging in Europe as a predominant serovar in fattening turkey flocks. This serovar was recorded as being predominant in the turkey sector in 2014 in the United Kingdom (UK). Only two years later, in 2016, it was also recorded in the turkey and broiler sectors in Ireland and Spain. These S. Derby isolates were characterised as members of the multilocus sequence type (MLST) profile 71 (ST71). For the first time, we characterise by whole genome sequencing (WGS) analysis a panel of 90 S. Derby ST71 genomes to understand the routes of transmission of this emerging pathogen within the poultry/turkey food trade. Selected panel included strains isolated as early as 2010 in five leading European g countries for turkey meat production. Twenty-one of the 90 genomes were extracted from a public database-Enterobase. Five of these originated from the United States (n=3), China (n=1) and Taiwan (n=1) isolated between 1986 and 2016. A phylogenomic analysis at the core-genome level revealed the presence of three groups. The largest group contained 97.5% of the European strains and included both, turkey and human isolates that were genetically related by an average of 35 ± 15 single nucleotide polymorphism substitutions (SNPs). To illustrate the diversity, the presence of antimicrobial resistance genes and phages were characteised in 30, S. Derby ST71 genomes, including 11 belonging to this study This study revealed an emergent turkey-related S. Derby ST71 clone circulating in at least five European countries (the UK, Germany, Poland, Italy, and France) since 2010 that causes human gastroenteritis. A matter of concern is the identification of a gyrA mutation involved in resistance to quinolone, present in the Italian genomes. Interestingly, the diversity of phages seems to be related to the geographic origins. These results constitute a baseline for following the spread of this emerging pathogen and identifying appropriate monitoring and prevention measures

Aminopeptidase B, a glucagon-processing enzyme: site directed mutagenesis of the Zn2+-binding motif and molecular modelling

<p>Abstract</p> <p>Background</p> <p>Aminopeptidase B (Ap-B; EC 3.4.11.6) catalyzes the cleavage of basic residues at the N-terminus of peptides and processes glucagon into miniglucagon. The enzyme exhibits, <it>in vitro</it>, a residual ability to hydrolyze leukotriene A₄into the pro-inflammatory lipid mediator leukotriene B₄. The potential bi-functional nature of Ap-B is supported by close structural relationships with LTA₄hydrolase (LTA₄H ; EC 3.3.2.6). A structure-function analysis is necessary for the detailed understanding of the enzymatic mechanisms of Ap-B and to design inhibitors, which could be used to determine the complete <it>in vivo </it>functions of the enzyme.</p> <p>Results</p> <p>The rat Ap-B cDNA was expressed in <it>E. coli </it>and the purified recombinant enzyme was characterized. 18 mutants of the H³²⁵EXXHX₁₈E³⁴⁸Zn²⁺-binding motif were constructed and expressed. All mutations were found to abolish the aminopeptidase activity. A multiple alignment of 500 sequences of the M1 family of aminopeptidases was performed to identify 3 sub-families of exopeptidases and to build a structural model of Ap-B using the x-ray structure of LTA₄H as a template. Although the 3D structures of the two enzymes resemble each other, they differ in certain details. The role that a loop, delimiting the active center of Ap-B, plays in discriminating basic substrates, as well as the function of consensus motifs, such as RNP1 and Armadillo domain are discussed. Examination of electrostatic potentials and hydrophobic patches revealed important differences between Ap-B and LTA₄H and suggests that Ap-B is involved in protein-protein interactions.</p> <p>Conclusion</p> <p>Alignment of the primary structures of the M1 family members clearly demonstrates the existence of different sub-families and highlights crucial residues in the enzymatic activity of the whole family. <it>E. coli </it>recombinant enzyme and Ap-B structural model constitute powerful tools for investigating the importance and possible roles of these conserved residues in Ap-B, LTA₄H and M1 aminopeptidase catalytic sites and to gain new insight into their physiological functions. Analysis of Ap-B structural model indicates that several interactions between Ap-B and proteins can occur and suggests that endopeptidases might form a complex with Ap-B during hormone processing.</p