272 research outputs found

    The oxygen-assisted transformation of propane to COx/H2 through combined oxidation and WGS reactions catalyzed by vanadium oxide-based catalysts

    Get PDF
    This paper reports about the gas-phase oxidation of propane catalyzed by bulk vanadium oxide and by alumina- and silica-supported vanadium oxide. The reaction was studied with the aim of finding conditions at which the formation of H2 and CO2 is preferred over that of CO, H2O and of products of alkane partial oxidation. It was found that with bulk V2O5 considerable amounts of H2 are produced above 400 8C, the temperature at which the limiting reactant, oxygen, is totally consumed. The formation of H2 derived from the combination of: (i) oxidation reactions, with generation of CO, CO2, oxygenates (mainly acetic acid), propylene and H2O, all occurring in the fraction of catalytic bed that operated in the presence of gas-phase oxygen, and (ii) WGS reaction, propane dehydrogenation and coke formation, that instead occurred in the fraction of bed operating under anaerobic conditions. This combination of different reactions in a single catalytic bed was possible because of the reduction of V2O5 to V2O3 at high temperature, in the absence of gas-phase oxygen. In fact, vanadium sesquioxide was found to be an effective catalyst for the WGS, while V2O5 was inactive in this reaction. The same combination of reactions was not possible when vanadium oxide was supported over high-surface area silica or alumina; this was attributed to the fact that in these catalysts vanadium was not reduced below the oxidation state V4+, even under reaction conditions leading to total oxygen conversion. In consequence, these catalysts produced less H2 than bulk vanadium oxide

    Health economic assessment tools (HEAT) for walking and for cycling

    Get PDF
    Physical inactivity is a significant public health problem in most regions of the world, which is unlikely to be solved by classical health promotion approaches alone. The promotion of active transport (cycling and walking) for everyday physical activity is a win-win approach; it not only promotes health but can also lead to positive environmental effects, especially if cycling and walking replace short car trips. Cycling and walking can also be more readily integrated into people’s busy schedules than, for example, leisure-time exercise. These forms of physical activity are also more practicable for groups of the population for which sport is either not feasible because of physical limitations or is not an accessible leisure activity for economic, social or cultural reasons. There is a large potential for active travel in European urban transport, as many trips are short and would be amenable to being undertaken on foot or by bicycle. This, however, requires effective partnerships with the transport and urban planning sectors, whose policies are key driving forces in providing appropriate conditions for such behavioural changes to take place. This has been recognized by a number of international policy frameworks, such as the Action Plan for implementation of the European Strategy for the Prevention and Control of Noncommunicable Diseases 2012–2016, adopted by the WHO Regional Committee for Europe (1). The strategy identifies the promotion of active mobility as one of the supporting interventions endorsed by WHO Member States to address this highpriority topic in the European Region, as do other international policy frameworks such as the Toronto Charter for Physical Activity launched in May 2010 as a global call for action (2)

    Minimal Anomalous U(1)' Extension of the MSSM

    Full text link
    We study an extension of the MSSM by an anomalous abelian vector multiplet and a St\"uckelberg multiplet. The anomalies are cancelled by the Green-Schwarz mechanism and the addition of Chern-Simons terms. The advantage of this choice over the standard one is that it allows for arbitrary values of the quantum numbers of the extra U(1). As a first step towards the study of hadron annihilations producing four leptons in the final state (a clean signal which might be studied at LHC) we then compute the decays Z'\to Z_0 \g and ZZ0Z0Z'\to Z_0 Z_0. We find that the largest values of the decay rate is 104\sim 10^{-4} GeV, while the expected number of events per year at LHC is at most of the order of 10.Comment: 45 pages, 8 eps figures, feynmf. Phenomenological section expanded. 2 plots and references adde

    Loss of beta-catenin triggers oxidative stress and impairs hematopoietic regeneration

    Get PDF
    Accidental or deliberate ionizing radiation exposure can be fatal due to widespread hematopoietic destruction. However, little is known about either the course of injury or the molecular pathways that regulate the subsequent regenerative response. Here we show that the Wnt signaling pathway is critically important for regeneration after radiation-induced injury. Using Wnt reporter mice, we show that radiation triggers activation of Wnt signaling in hematopoietic stem and progenitor cells. β-Catenin-deficient mice, which lack the ability to activate canonical Wnt signaling, exhibited impaired hematopoietic stem cell regeneration and bone marrow recovery after radiation. We found that, as part of the mechanism, hematopoietic stem cells lacking β-catenin fail to suppress the generation of reactive oxygen species and cannot resolve DNA double-strand breaks after radiation. Consistent with the impaired response to radiation, β-catenin-deficient mice are also unable to recover effectively after chemotherapy. Collectively, these data indicate that regenerative responses to distinct hematopoietic injuries share a genetic dependence on β-catenin and raise the possibility that modulation of Wnt signaling may be a path to improving bone marrow recovery after damage

    St\"uckelino Dark Matter in Anomalous U(1)' Models

    Full text link
    We study a possible dark matter candidate in the framework of a minimal anomalous U(1)U(1)' extension of the MSSM. It turns out that in a suitable decoupling limit the St\"uckelino, the fermionic degree of freedom of the St\"uckelberg multiplet, is the lightest supersymmetric particle (LSP). We compute the relic density of this particle including coannihilations with the next to lightest supersymmetric particle (NLSP) and with the next to next to lightest supersymmetric particle (NNLSP) which are assumed almost degenerate in mass. This assumption is needed in order to satisfy the stringent limits that the Wilkinson Microwave Anisotropy Probe (WMAP) puts on the relic density. We find that the WMAP constraints can be satisifed by different NLSP and NNLSP configurations as a function of the mass gap with the LSP. These results hold in the parameter space region where the model remains perturbative.Comment: 21 pages, 6 figures, improved section 5, revised version published on EPJ

    The legacy of Corrado Gini in population studies

    Get PDF
    This volume contains 12 papers that range over many different research subjects, taking in many of the population questions that, directly or indirectly, absorbed Corrado Gini as demographer and social scientist over several decades. They vary from the analysis of the living conditions and behaviours of the growing foreign population (measurements and methods of analysis, socio-economic conditions and health, ethnic residential segregation, sex-ratio at birth), to studies on the homogamy of couples; from population theories (with reference to the cyclical theory of populations) to the modelling approach to estimating mortality in adult ages or estimating time transfers, by age and sex, related to informal child care and adult care; from historical studies that take up themes dear to Gini (such as the estimates of Italian military deaths in WWI), to the application of Gini’s classical measurements to studying significant phenomena today (transition to adulthood and leaving the parental home, health care, disabled persons and social integration). The subjects and measurements that appear here are not intended to exhaust the broad spectrum of Gini’s research work in the demographic and social field (nor could they), but they can make up a part of the intersection between his vast legacy and some interesting topics in current research, some of which were not even imaginable in the mid twentieth century. Looking at the many contributions that celebrated Gini in Treviso and thinking about his legacy, it seems possible to identify at least two typologies of approach, to be found in this issue of the journal, too. On the one hand, there are contributions that aim to retrieve and discuss themes, methodologies and measurements dealt with or used by Gini so as to evaluate their present relevance and importance in the current scholarly debate. On the other, there are contributions that deal with topics that are far from Gini’s work, as they study very recent phenomena, but actually, among other things, make use of methods and indicators devised by Gini that are now so much part of the common currency of methodology, so they don’t require explicit reference to their Author

    Fasciolosis en bovinos hembras en crecimiento del Departamento Berón de Astrada (Corrientes, Argentina)

    Get PDF
    El objetivo del trabajo fue estudiar la evolución de la fasciolosis bovina a largo plazo, a partir hembras en crecimiento al pie de madre y hasta los 3 años de edad, efectuando el diagnóstico in vivo por coprología y evaluando la respuesta al tratamiento instaurado (albendazole). Las tareas de campo se realizaron en un establecimiento del Departamento Berón de Astrada (Corrientes, Argentina), zona donde la infestación del ganado con Fasciola hepatica es enzoótica. El grupo investigado estuvo inicialmente constituido por 78 animales, los que al final del ensayo se redujeron a 30. Se realizaron seis muestreos de materia fecal para estudios coprológicos por sedimentación (Dennis), los tres primeros coincidentes con los tres tratamientos antiparasitarios efectuados. El día 0 se verificó un 3,85% de animales positivos. La tasa fue de 1,30% al día 71 y de 0% durante los dos muestreos sucesivos, a los 172 y 230 días, avalando la eficacia de los tratamientos recibidos. La interrupción de la administración del antiparasitario provocó que la “fasciolosis” reapareciera al día 553 con 7,69% de animales positivos, nivel que ascendió al 80% el día 850 (ultimo muestreo). Se concluye alertando sobre los efectos contraproducentes de la práctica habitual de interrumpir los tratamientos antiparasitarios contra F. hepatica en animales adultos, porque ellos son losgrandes diseminadores de esta enfermedad parasitaria

    Presencia de Pseudosuccinea columella naturalmente infestada con Fasciola hepatica en Santo Tomé (Corrientes, Argentina)

    Get PDF
    La fasciolosis es una enfermedad producida por Fasciola hepatica. Esta parasitosis produce grandes pérdidas económicas en el ganado bovino de la Provincia de Corrientes, Argentina, y también tiene carácter zoonótico. En el norte de la Provincia, Pseudosuccinea columella es el caracol involucrado en la transmisión de la enfermedad. El objetivo del presente trabajo fue ampliar los datos sobre la distribución de P. columella y su infestación natural por F. hepatica en la Provincia de Corrientes. Se recolectaron caracoles en un establecimiento ganadero del Departamento de Santo Tomé, al nordeste de la Provincia, que fueron identificados taxonómicamente, medidos y disecados para verificar la presencia de cercarias de F. hepatica. Los 115 caracoles recolectados fueron identificados como P. columella. La longitud de la conchilla varió entre 0,8–21,3 mm, con una media de 10,0 mm. La prevalencia de caracoles naturalmente infestados por F. hepatica fue de 8 (7,4%) sobre 108 examinados. La presencia de P. columella en distintos departamentos del norte y nordeste de la Provincia de Corrientes y las altas prevalencias de infestación natural por F. hepatica registradas, indicarían el asentamiento de un ciclo de transmisión enzoótica en esta zona

    Implications of the 125 GeV Higgs boson for scalar dark matter and for the CMSSM phenomenology

    Full text link
    We study phenomenological implications of the ATLAS and CMS hint of a 125±1125\pm 1 GeV Higgs boson for the singlet, and singlet plus doublet non-supersymmetric dark matter models, and for the phenomenology of the CMSSM. We show that in scalar dark matter models the vacuum stability bound on Higgs boson mass is lower than in the standard model and the 125 GeV Higgs boson is consistent with the models being valid up the GUT or Planck scale. We perform a detailed study of the full CMSSM parameter space keeping the Higgs boson mass fixed to 125±1125\pm 1 GeV, and study in detail the freeze-out processes that imply the observed amount of dark matter. After imposing all phenomenological constraints except for the muon (g2)μ,(g-2)_\mu, we show that the CMSSM parameter space is divided into well separated regions with distinctive but in general heavy sparticle mass spectra. Imposing the (g2)μ(g-2)_\mu constraint introduces severe tension between the high SUSY scale and the experimental measurements -- only the slepton co-annihilation region survives with potentially testable sparticle masses at the LHC. In the latter case the spin-independent DM-nucleon scattering cross section is predicted to be below detectable limit at the XENON100 but might be of measurable magnitude in the general case of light dark matter with large bino-higgsino mixing and unobservably large scalar masses.Comment: 17 pages, 7 figures. v3: same as published versio
    corecore