2,629 research outputs found
Prediction of service life of polymeric sealant compositions for fuel tanks in aerospace structures from measurements of viscoelastic properties Annual report
Prediction of service life of polymeric sealers for fuel tanks from viscoelastic measurement
Mass accretion rates of clusters of galaxies: CIRS and HeCS
We use a new spherical accretion recipe tested on N-body simulations to
measure the observed mass accretion rate (MAR) of 129 clusters in the Cluster
Infall Regions in the Sloan Digital Sky Survey (CIRS) and in the Hectospec
Cluster Survey (HeCS). The observed clusters cover the redshift range of
and the mass range of . Based on three-dimensional mass profiles of simulated
clusters reaching beyond the virial radius, our recipe returns MARs that agree
with MARs based on merger trees. We adopt this recipe to estimate the MAR of
real clusters based on measurements of the mass profile out to .
We use the caustic method to measure the mass profiles to these large radii. We
demonstrate the validity of our estimates by applying the same approach to a
set of mock redshift surveys of a sample of 2000 simulated clusters with a
median mass of as well as a sample
of 50 simulated clusters with a median mass of : the median MARs based on the caustic mass profiles of
the simulated clusters are unbiased and agree within with the median
MARs based on the real mass profile of the clusters. The MAR of the CIRS and
HeCS clusters increases with the mass and the redshift of the accreting
cluster, which is in excellent agreement with the growth of clusters in the
CDM model.Comment: 25 pages, 19 figures, 7 table
Promocionando una ingeniería global a través de la movilidad estudiantil: formación de voluntariado y estadías de corta duración en programas de cooperación al desarrollo
1
Impreso de Ponencias y Comunicaciones
Área de Estudio: Área 4: EpD y Sensibilización
Naturaleza del trabajo (ponencia o comunicación):
Promocionando una ingeniería global a través de la movilidad estudiantil: formación de
voluntariado y estadías de corta duración
en programas de cooperación al desarrollo.
Resumen
La participación en programas de coope
ración al desarrollo es un instrumento
privilegiado de educación para el desarrollo y,
más en general, en valores como la paz,
la sostenibilidad o la interculturalidad. En
este trabajo se describe el Programa de
Conocimiento de Realidad, impulsado por Ingenier
ía Sin Fronteras dentro de su línea de
educación para el desarrollo, que incorpora
diferentes posibilidades de intercambio y
participación de estudiantes de universidad
en programas de cooperación con una clara
vertiente tecnológica.
Las estancias, por lo general su primera expe
riencia en un país en desarrollo, pretenden
acercar a los participantes a la realidad de
las comunidades desfavorecidas a través de
un trabajo técnico de apoyo a un programa de
cooperación al desarrollo. Entre 1999 y el
2005, se han movilizado 71 estudiantes de la
Universidad Politécnica de Cataluña en
actividades del programa desarrolladas en El
Salvador, Argentina, Camerún y Perú.
Muchos de ellos han mantenido después un
fuerte compromiso en el área de la
cooperación para el desarrollo.Postprint (published version
The prevalences of Salmonella Genomic Island 1 variants in human and animal Salmonella Typhimurium DT104 are distinguishable using a Bayesian approach
Throughout the 1990s, there was an epidemic of multidrug resistant Salmonella Typhimurium DT104 in both animals and humans in Scotland. The use of antimicrobials in agriculture is often cited as a major source of antimicrobial resistance in pathogenic bacteria of humans, suggesting that DT104 in animals and humans should demonstrate similar prevalences of resistance determinants. Until very recently, only the application of molecular methods would allow such a comparison and our understanding has been hindered by the fact that surveillance data are primarily phenotypic in nature. Here, using large scale surveillance datasets and a novel Bayesian approach, we infer and compare the prevalence of Salmonella Genomic Island 1 (SGI1), SGI1 variants, and resistance determinants independent of SGI1 in animal and human DT104 isolates from such phenotypic data. We demonstrate differences in the prevalences of SGI1, SGI1-B, SGI1-C, absence of SGI1, and tetracycline resistance determinants independent of SGI1 between these human and animal populations, a finding that challenges established tenets that DT104 in domestic animals and humans are from the same well-mixed microbial population
Crisis and Non-Crisis Short Selling and Bank Enforcement Actions
Employing standard informed trading intuition, we develop testable hypotheses regarding short selling before and after bank enforcement action (EA) initiations. For U.S.-listed bank firm data for 2007 to 2012, we find strong support for differentiated short seller activity and skill in crisis versus non-crisis periods. In financial crises, short sellers predominantly position prior to EAs. The EA initiations then act as information-homogenizing and profit-taking events reducing incentives to remain positioned. In contrast, EAs in non-crisis periods appear to serve as wake-up calls that attract additional short selling. Our findings offer potentially important insights for regulators considering short sellers’ reactions to EA announcements in general, during financial crises, and when not experiencing a broad financial crisis
Paleomagnetic dating of non-sulfide Zn-Pb ores in SW Sardinia (Italy): a first attempt
A first paleomagnetic investigation aimed at constraining the age of the non-sulfide Zn-Pb ore deposits in the
Iglesiente district (SW Sardinia, Italy) was carried out. In these ores, the oxidation of primary sulfides, hosted
in Cambrian carbonate rocks, was related to several paleoweathering episodes spanning from the Mesozoic onward.
Paleomagnetic analyses were performed on 43 cores from 4 different localities, containing: a) non-oxidized
primary sulfides and host rock, b) oxidized Fe-rich hydrothermal dolomites and (c) supergene oxidation
ore («Calamine»). Reliable data were obtained from 18 samples; the others show uninterpretable results due to
low magnetic intensity or to scattered demagnetization trajectories. Three of them show a scattered Characteristic
Remanent Magnetization (ChRM), likely carried by the original (i.e. Paleozoic) magnetic iron sulfides. The
remaining 15 samples show a well defined and coherent ChRM, carried by high-coercivity minerals, acquired
after the last phase of counterclockwise rotation of Sardinia (that is after 16 Myr), in a time interval long enough
to span at least one reversal of the geomagnetic field. Hematite is the main magnetic carrier in the limestone,
whereas weathered hydrothermal dolomite contains goethite or a mixture of both. The results suggest that paleomagnetism
can be used to constrain the timing of oxidation in supergene-enriched ores
Mathematical Models for a New Era of Malaria Eradication
Maciej Boni and colleagues discuss a new model exploring how a switch in antimalarial drug use to artemisinin-based combination therapies will affect malaria prevalence and incidence in endemic regions
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Safety of guselkumab in hepatitis B virus infection
Reactivation of hepatitis B virus (HBV) following the use of TNF antagonists has been reported and is a contraindication to use of these medications. Although the risk of reactivation of HBV during use of ustekinumab and secukinumab is low in patients with only HBV core antibody positivity, the risk is substantial in patients with chronic HBV infection. Less information is available regarding the use of pure IL-23 antagonists. Herein we discuss the successful treatment with guselkumab of a patient with HBV core antibody positivity, without evidence of HBV reactivation or other liver complications
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