A First Step Towards Automatically Building Network Representations

To fully harness Grids, users or middlewares must have some knowledge on the topology of the platform interconnection network. As such knowledge is usually not available, one must uses tools which automatically build a topological network model through some measurements. In this article, we define a methodology to assess the quality of these network model building tools, and we apply this methodology to representatives of the main classes of model builders and to two new algorithms. We show that none of the main existing techniques build models that enable to accurately predict the running time of simple application kernels for actual platforms. However some of the new algorithms we propose give excellent results in a wide range of situations

Aaron Spell Medical Receipt, 1842 1843

Itemized medical receipt for treatment and medicine provided to the Aaron Spell family and a slave by Dr. W. T. (William T.) LeGrand between 22 July 1842 and April 1843.https://scholarsjunction.msstate.edu/mss-spell-papers/1026/thumbnail.jp

Prevalence of respiratory pathogens in nasal swabs from horses with acute respiratory disease in Belgium

Contagious respiratory infections are an important cause of respiratory disease in horses, resulting in impaired pulmonary function, poor performance and sometimes severe illness. Although bacterial infections are often suspected to be involved, viruses are frequently overlooked and are an underestimated cause of respiratory disease outbreaks in horses. In this study, nasal swabs of 103 horses with acute symptoms of respiratory disease were analyzed for the presence of 13 different respiratory pathogens. Gamma herpesviruses were the most commonly detected, with 60% of the samples being positive, followed by streptococcus equi subsp. zooepidemicus infection (30%). Rhinovirus B, streptococcus equi subsp. equi, adenovirus 1 and EHV-4 were more rarely detected. Further research is necessary to correctly interpret the importance of gamma herpesviruses in horses, for example by screening a healthy control population. National surveillance of respiratory viruses in horses by PCR analysis on nasal swabs might be a useful, early warning system for viral epidemics

Stress fractures in 2011: practical approach

Stress fractures occur when excessive loads are applied to a bone whose mechanical strength is normal. Bone insufficiency fractures, in contrast, are due to physiological loads applied to bone of inadequate mechanical strength [1]. This contradistinction is obviously an oversimplifi cation. In practice, a continuum exists between these two clearly defined situations. The objective of the third ODISSEE meetings [2,3] held under the aegis of the GRIO was to review current knowledge on stress fractures. The pathophysiology of stress fractures is still poorly understood. When loads are applied to a bone, particularly in a repetitive manner, an elastic deformity occurs, followed by a plastic deformity and, finally, by microfractures. Bone strength varies across individuals. It depends not only on the intrinsic qualities of the bone tissue, but also on the magnitude and repetitiveness of the loads applied to the bone. Bone tissue fatigue is an inability to repair the microdamage caused by mechanical loading. The number and length of the microfractures increase, resulting in a fracture with clinical symptoms and radiographic changes [4]. Stress fractures are a common reason for physician visits among athletes and military recruits. They account for 5% to 14% of all physician visits, depending on the study population [5,6]. Although stress fractures can arise at any site, the most common locations are the tibia, particularly in runners; the metatarsals (most notably the second and third metatarsals) in hikers, runners, dancers, and military recruits; the iliopubic and ischiopubic rami of the pelvis in military recruits, gymnasts, dancers, and soccer players; and the femur in cross-country runners. The calcaneus is also a common site of involvement in all populations. Stress fractures are rare at the upper limbs, except in high- level gymnasts country runners. The calcaneus is also a common site of involvement in all populations. Stress fractures are rare at the upper limbs,except in high-level gymnasts

The low-field conductivity of zeolite-encapsulated molecular wires

The first measurements of an upper bound for the low-field conductivity of a molecular wire are presented here. We were able to encapsulate polypyrrole with chain lengths more than 10 monomers within the channels of different zeolites. Although the chains are fully oxidized by intrazeolite Fe3 + ions, and should conduct (when included in a bulk polymer), they do not exhibit, in the zeolite, significant ac conductivity up to 1 GHz. This suggests that other strategies than low field conductivity are needed to inject charges and transmit information through isolated molecular wires

The Infrared Difference Dust Index: Past, Present and Future

The Infrared Difference Dust Index (IDDI) [Legrand et al, 2001] is a Meteosat-derived thermal-infrared (TIR) index dedicated to remote sensing of desert aerosol over land (based on the former Meteosat First Generation (MFG) series). The IDDI product proves to be effective in studies of dust source location and seasonal activity [Brooks and Legrand, 2000; Léon and Legrand, 2003; Deepshikha et al, 2003a; b], in the physics of dust emission with respect to the surface properties [Chomette et al, 1999; Marticorena et al, 1997; 1999; 2004], for description of dust transport [Petit et al, 2005], of dust mineral composition [Caquineau et al, 2002] and for dust (meteorological) forecasting [Hu et al, 2008]. An improved algorithm and a new cloud masking technique applied to full resolution MFG IR images has given rise to an upgraded dust index. These improvements are described in the next section and resulting IDDI images are displayed and compared with images of the UV Aerosol Index (AI) from the Ozone Monitoring Instrument (OMI) aboard EOS-AURA. They are part of a database (to be completed), over the period 1981-2006 covered by MFG. Obviously, the 1-channel IDDI cannot match with the multi-channel data provided by the new spatial instruments (such as MSG/SEVIRI), but it has the advantage of covering a quarter century (1981-2006) and thus it is relevant for climate studies over this period (including the severe Sahelian drought of the 80s) as well as for investigating on the nature of the link between dust occurrence and epidemics of meningococcal meningitis in West Africa, throughout the 25 past years [Martiny et al, 2007]. In the last section of this abstract, the physical bases of dust remote sensing in the TIR during daylight are briefly presented. They allow to understand the fundamental differences with the more usual detection using channels in the solar spectrum (VIS and NIR) and they bear on the favorable or adverse conditions to produce a dust index of quality. Lastly, it is possible from such results to outline an approach for the determination of the TIR dust optical depth (or a dust index closely related to it), using the TIR channels IR8.7, IR10.8 and IR 12.0 of MSG/SEVIRI, as well as its median infrared (MIR) channel IR3.9

Optical second harmonic generation probe of two-dimensional ferroelectricity

Optical second harmonic generation (SHG) is used as a noninvasive probe of two-dimensional (2D) ferroelectricity in Langmuir-Blodgett (LB) films of copolymer vinylidene fluoride with trifluorethylene. The surface 2D ferroelectric-paraelectric phase transition in the topmost layer of LB films and a thickness independent (almost 2D) transition in the bulk of these films are observed in temperature studies of SHG.Comment: 9 pages, 2 figures, Optics Letters, in prin

Large perturbations of ammonium and organic acids content in the Summit-Greenland ice core. Fingerprint from forest fires?

Biomass burning is influencing the atmospheric chemistry by emitting large amounts of reactive species such as hydrocarbons, organic acids and nitrogen compounds [Andreae et al., 1988]. Polar ice cores provide a unique record of precipitation whose chemistry reflects the atmospheric composition at the time of deposition. The analysis of such ice samples therefore allows an estimate to be made of the concentration of atmospheric impurities in the past. During the first season of the deep drill operation (GRIP) at Summit, Central Greenland (72° 34' N, 37° 38'W) continuous ammonium (NH4+) measurements were performed between 100 and 600 m depth covering the time period from 330 to 2500 years B.P. The NH4+ concentrations show seasonal variations between 1–20 ng.g−1 with some sporadic high values up to 600 ng.g−1 in narrow layers. The chemical fingerprint points to biomass burning causing the high ammonium peaks

Hydrogenation of CO on a silica surface: an embedded cluster approach

The sequential addition of H atoms to CO adsorbed on a siliceous edingtonite surface is studied with an embedded cluster approach, using density functional theory for the quantum mechanical (QM) cluster and a molecular force field for the molecular mechanical (MM) cluster. With this setup, calculated QM/MM adsorption energies are in agreement with previous calculations employing periodic boundary conditions. The catalytic effect of the siliceous edingtonite (100) surface on CO hydrogenation is assessed because of its relevance to astrochemistry. While adsorption of CO on a silanol group on the hydroxylated surface did not reduce the activation energy for the reaction with a H atom, a negatively charged defect on the surface is found to reduce the gas phase barriers for the hydrogenation of both CO and H2C = O. The embedded cluster approach is shown to be a useful and flexible tool for studying reactions on (semi-)ionic surfaces and specific defects thereon. The methodology presented here could easily be applied to study reactions on silica surfaces that are of relevance to other scientific areas, such as biotoxicity of silica dust and geochemistry