Social dynamics in conferences: analyses of data from the Live Social Semantics application

Popularity and spread of online social networking in recent years has given a great momentum to the study of dynamics and patterns of social interactions. However, these studies have often been confined to the online world, neglecting its interdependencies with the offline world. This is mainly due to the lack of real data that spans across this divide. The Live Social Semantics application is a novel platform that dissolves this divide, by collecting and integrating data about people from (a) their online social networks and tagging activities from popular social networking sites, (b) their publications and co-authorship networks from semantic repositories, and (c) their real-world face-to-face contacts with other attendees collected via a network of wearable active sensors. This paper investigates the data collected by this application during its deployment at three major conferences, where it was used by more than 400 people. Our analyses show the robustness of the patterns of contacts at various conferences, and the influence of various personal properties (e.g. seniority, conference attendance) on social networking patterns

Geotechnical Units and the Damages Caused by Earthquakes in Valparaiso - Chile

The geotechnical units forming the foundation soil of Valparaiso city and constituting seven zones that exhibit different stratigraphic sequences are characterized. In addition, the evolution of the artificial backfilling’s located in the seaport is reported. The damages causes by Chile Earthquake of March 3, 1985 allow to establish for each zone the MSK intensities, which are varying between 7 1/2 and 8 1/2 in the flat-ground sector of Valparaiso, and between 7 1/4 and 7 1/2 in the hills. The major intensity in the flat sector is observed in areas whose artificial backfilling’s are exhibiting greater thickness and less consistency or less compacity

Negligible effects of tryptophan on the aflatoxin adsorption of sodium bentonite

The main objective of this study was to determine if the competitive adsorption of tryptophan (Trp) and aflatoxin B1 (AFB1) could potentially affect the ability of a sodium bentonite (NaB) to prevent aflatoxicosis in monogastric animals. The adsorption of Trp and AFB1 on this adsorbent is fast and could be operating on the same time-scale making competition feasible. In vitro competitive adsorption experiments under simulated gastrointestinal conditions were performed. A high affinity of the clay for Trp and NaB was observed. The effect of an excess of KCl to mimic the ionic strength of the physiological conditions were also investigated. A six-times decrease in the Trp surface excess at saturation was observed. A similar behaviour was previously found for AFB1 adsorption. Taking into account the amount of Trp adsorbed by the clay and the usual adsorbent supplementation level in diets, a decrease in Trp bioavailability is not expected to occur. Tryptophan adsorption isotherms on NaB were ‘S’-shaped and were adjusted by the Frumkin–Fowler–Guggenheim model. The reversibility of the adsorption processes was investigated in order to check a potential decrease in the ability of NaB to protect birds against chronic aflatoxicoses. Adsorption processes were completely reversible for Trp, while almost irreversible for AFB1. In spite of the high affinity of the NaB for Trp, probably due to the reversible character of Trp adsorption, no changes in the AFB1 adsorption isotherm were observed when an excess of the amino acid was added to the adsorption medium. As a consequence of the preferential and irreversible AFB1 adsorption and the reversible weak binding of Trp to the NaB, no changes in the aflatoxin sorption ability of the clay are expected to occur in the gastrointestinal tract of birds.Fil: Magnoli, Alejandra Paola. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Copia, P.. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; ArgentinaFil: Monge, Maria del Pilar. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Magnoli, Carina Elizabeth. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Dalcero, Ana Maria. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Chiacchiera, Stella Maris. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

On the oxidation mechanism of pure tungsten in the temperature range 600-800 ºC

The oxidation behavior of International Thermonuclear Experimental Reactor (ITER)-reference tungsten grade has been evaluated in dry air in the temperature range 600-800 °C. At 600 °C , the scale remained protective while the integrity of W₁₈O₄₉ layer was kept. Rapid increase in mass gain resulted from massive cracking at local areas in the W₁₈O₄₉ layer. Then, a coarse non-protective columnar WO₂.₉₂ scale was developed which favoured rapid inward oxygen transport into the alloy. At 700 and 800 °C, growth stresses in the scale were released through local cracking. At this stage, WO₂.₉₂ became progressively transformed into WO₃ when the oxygen partial pressure increased across the scale thickness.This investigation was supported by the Spanish Ministry of Science and Innovation (ENE2008 06,403 C06 04). The financial support from the Comunidad de Madrid, through the program TECHNOFUSION, Grant S2009/ENE 1679

Oxidation behaviour of tungsten with vanadium additions

The effect of vanadium additions on the oxidation behaviour of tungsten has been evaluated at 600 °C in dry air. Mass gain in V-containing tungsten alloys is practically the same than that of pure tungsten processed by a conventional route. The advantage of vanadium alloying arises from the suppression of periodical microcracking described during the oxidation of pure tungsten, although the scale developed during the initial stages is very porous and it is not an effective barrier for inward oxygen ingress. Further protection is conferred when an outermost dense WO3 layer is formed at the air/scale interface by condensation of volatile W and V oxides, turning the kinetics from linear to parabolic

Kinematics of the ionized-to-neutral interfaces in Monoceros R2

Context. Monoceros R2 (Mon R2), at a distance of 830 pc, is the only ultra-compact H ii region (UC H ii) where its associated photon-dominated region (PDR) can be resolved with the Herschel Space Observatory. Aims. Our aim is to investigate observationally the kinematical patterns in the interface regions (i.e., the transition from atomic to molecular gas) associated with Mon R2. Methods. We used the HIFI instrument onboard Herschel to observe the line profiles of the reactive ions CH+, OH+ and H2O+ toward different positions in Mon R2. We derive the column density of these molecules and compare them with gas-phase chemistry models. Results. The reactive ion CH+ is detected both in emission (at central and red-shifted velocities) and in absorption (at blue-shifted velocities). OH+ is detected in absorption at both blue- and red-shifted velocities, with similar column densities. H2O+ is not detected at any of the positions, down to a rms of 40 mK toward the molecular peak. At this position, we find that the OH+ absorption originates in a mainly atomic medium, and therefore is associated with the most exposed layers of the PDR. These results are consistent with the predictions from photo-chemical models. The line profiles are consistent with the atomic gas being entrained in the ionized gas flow along the walls of the cavity of the H ii region. Based on this evidence, we are able to propose a new geometrical model for this region. Conclusions. The kinematical patterns of the OH+ and CH+ absorption indicate the existence of a layer of mainly atomic gas for which we have derived, for the first time, some physical parameters and its dynamics.Comment: 6 pages, 5 figures. Accepted for publication in A&

Influence of processing route and yttria additions on the oxidation behavior of tungsten

This study is for: The Fifteenth International Conference on Fusion Reactor Materials (ICFRM-15) was held October 16–22, 2011, at the Charleston Marriott Hotel in Charleston, South Carolina (American United States).The oxidation resistance in dry air of pure tungsten and tungsten reinforced with a dispersion of 0.6 wt.% Y₂O₃ nanoparticles has been evaluated between 873 and 1073 K, temperature range that divertor in fusion power plants should endure during long-term times in the case of loss of coolant accident and/or air ingress in the vessel. Both materials were prepared by a powder metallurgy route involving hot isostatic pressing of ball milled tungsten powders and tungsten with dispersed Y₂O₃ nanoparticles. The results have been compared with those of pure tungsten processed by conventional techniques. Thermogravimetric tests at 873 K revealed that the processing route as well as yttria addition considerably affected the oxidation resistance of pure tungsten. Mass gain of W-0.6Y₂O₃ at 873 K was five and two times lower than that of pure tungsten prepared by conventional processing techniques and by powder metallurgy, respectively. This different behavior was related to changes in the structure and composition of the oxide scale. Above 873 K, the kinetics were significantly accelerated for all materials due to the development of a non-protective oxide scale from the earliest oxidation stages, although the kinetics of Y₂O₃-containing material were still the slowest, specially at 973 K. It was analyzed how yttria additions modify the oxidation mechanism of tungsten.Consejería de Educación de la Comunidad de Madrid through the program ESTRUMAT-CM S2009MAT-1585 and by the Ministerio de Innovación y Ciencia (Project ENE2008-06403-C06-04). The additional subvention from EURATOM/CIEMAT association through contract EFDA WP11-MAT-WWALLOY.Publicad