31 research outputs found

    Exploring Mexican adolescents' perceptions of environmental health risks: a photographic approach to risk analysis

    Get PDF
    The objective of this study was to explore Mexican adolescents' perceptions of environmental health risks in contaminated urban areas, and to test the environmental photography technique as a research tool for engaging adolescents in community-based health research. The study was conducted with 74 adolescents from two communities in the city of San Luis Potosi, Mexico. Participants were provided with disposable cameras and asked to take photographs of elements and situations which they believed affected their personal health both at home and outside their homes. They were also asked to describe each photograph in writing. Photographs and written explanations were analyzed by using quantitative and qualitative content analysis. Risk perception plays a crucial role in the development of Risk Communication Programs (RCPs) aimed at the improvement of community health. The photography technique opens up a promising field for environmental health research since it affords a realistic and concise impression of the perceived risks. Adolescents in both communities perceived different environmental health risks as detrimental to their well-being, e.g. waste, air pollution, and lack of hygiene. Yet, some knowledge gaps remain which need to be addressed

    Global link between deformation and volcanic eruption quantified by satellite imagery

    Get PDF
    A key challenge for volcanological science and hazard management is that few of the world’s volcanoes are effectively monitored. Satellite imagery covers volcanoes globally throughout their eruptive cycles, independent of ground-based monitoring, providing a multidecadal archive suitable for probabilistic analysis linking deformation with eruption. Here we show that, of the 198 volcanoes systematically observed for the past 18 years, 54 deformed, of which 25 also erupted. For assessing eruption potential, this high proportion of deforming volcanoes that also erupted (46%), together with the proportion of non-deforming volcanoes that did not erupt (94%), jointly represent indicators with ‘strong’ evidential worth. Using a larger catalogue of 540 volcanoes observed for 3 years, we demonstrate how this eruption–deformation relationship is influenced by tectonic, petrological and volcanic factors. Satellite technology is rapidly evolving and routine monitoring of the deformation status of all volcanoes from space is anticipated, meaning probabilistic approaches will increasingly inform hazard decisions and strategic development

    Flow Dominance and Factorization of Transverse Momentum Correlations in Pb-Pb Collisions at the LHC

    Get PDF
    We present the first measurement of the two-particle transverse momentum differential correlation function, P2≡ ΔpTΔpT/ pT2, in Pb-Pb collisions at sNN=2.76 TeV. Results for P2 are reported as a function of the relative pseudorapidity (Δη) and azimuthal angle (Δφ) between two particles for different collision centralities. The Δφ dependence is found to be largely independent of Δη for |Δη|≥0.9. In the 5% most central Pb-Pb collisions, the two-particle transverse momentum correlation function exhibits a clear double-hump structure around Δφ=π (i.e., on the away side), which is not observed in number correlations in the same centrality range, and thus provides an indication of the dominance of triangular flow in this collision centrality. Fourier decompositions of P2, studied as a function of the collision centrality, show that correlations at |Δη|≥0.9 can be well reproduced by a flow ansatz based on the notion that measured transverse momentum correlations are strictly determined by the collective motion of the system

    K*(892)(0) and phi(1020)meson production at high transverse momentum in pp and Pb-Pb collisions at root sNN=2.76 TeV

    Get PDF
    The production of K∗(892)0 and φ(1020) mesons in proton-proton (pp) and lead-lead (Pb-Pb) collisions at √sNN = 2.76 TeV has been analyzed using a high luminosity data sample accumulated in 2011 with the ALICE detector at the Large Hadron Collider (LHC). Transverse momentum (pT) spectra have been measured for K∗(892)0 and φ(1020) mesons via their hadronic decay channels for pT up to 20 GeV/c. The measurements in pp collisions have been compared to model calculations and used to determine the nuclear modification factor and particle ratios. The K∗(892)0/K ratio exhibits significant reduction from pp to central Pb-Pb collisions, consistent with the suppression of the K∗(892)0 yield at low pT due to rescattering of its decay products in the hadronic phase. In central Pb-Pb collisions the pT dependent φ(1020)/π and K∗(892)0/π ratios show an enhancement over pp collisions for pT ≈ 3 GeV/c, consistent with previous observations of strong radial flow. At high pT, particle ratios in Pb-Pb collisions are similar to those measured in pp collisions. In central Pb-Pb collisions, the production of K∗(892)0 and φ(1020) mesons is suppressed for pT > 8 GeV/c. This suppression is similar to that of charged pions, kaons, and protons, indicating that the suppression does not depend on particle mass or flavor in the light quark sector

    The Patagonian Fossil Lizards

    No full text
    The squamates constitute a significant part of the present-day South American herpetofauna, being their fossils a crucial evidence for understanding the origin and evolution of the main clades. The fossil record of squamates in Patagonia is still scarce but it represents one of the most prolific of entire South America. An updated systematic review of the available information of Patagonian fossil lizards is summarized in this chapter. The oldest lizards of Patagonia are found as back as the Upper Cretaceous and include materials referred to two of the most diverse extant clades: Iguania and Scincomorpha. Palaeocene and Eocene interestingly do not provide any lizard specimen from this region. The record reappeared in the Late Oligocene with iguanians. A significant increasing of materials is revealed later in the Neogene. Early Miocene lizards include the first appearance of extant species (the iguanids Liolaemus and Pristidactylus, and the teiids Tupinambis and Callopistes). Late Early Miocene deposits provide materials of Pristidactylus and Tupinambis, whereas an indeterminate tupinambine of the Mid-Miocene is the youngest Neogene record of a lizard in Patagonia. Palaeoclimatic changes affected the distributional patterns of lizards in Patagonia, restricting the distribution of Pristidactylus and Tupinambis which, during the Miocene, reached localities southern than at present. The uplift of the austral Andean cordillera would have been decisive for the diversification of Liolaemus and Pristidactylus at both sides the Andes, whereas the trans-Andean teiid Callopistes had a widespread distribution in the past, reaching the Pampean Region and Patagonia, in Argentina.Fil: Albino, Adriana Maria. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentin
    corecore