112 research outputs found

    Cartografía geoquímica multielemental en sedimentos de corriente en un contexto de arco isla volcánico. Aplicación al análisis de potencialidad metalogénica en un area de la República Dominicana

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    Este estudio presenta los principales resultados y conclusiones de la exploración y cartografía geoquímica multielemental llevada a cabo, a partir de muestras de sedimentos de arroyo, en el sector de Bonao-Constanza de la Cordillera Central de la República Dominicana. En el área estudiada, de 3.800 km2, fueron recogidas 684 muestras, con una densidad de muestreo de 1 muestra / 5 km2, en las que se analizaron 48 elementos químicos por técnicas de ICPAES y Activación Neutrónica. Esta zona, situada en el ámbito del arco isla de borde de la placa caribeña, contiene importantes mineralizaciones de carácter epitermal y volcanosedimentario y posee un gran potencial de nuevas mineralizaciones. Dada la complejidad geológica y los fenómenos superimpuestos de alteración hidrotermal, la geoquímica multielemental permite, a través del análisis de las pautas de distribución espacial de los elementos y de las asociaciones geoquímicas, una definición más razonada de áreas anómalas, su valoración, y un conocimiento de su posible significado en relación con el contexto petrogenético, geológico y geoquímico en el que se hallan. La información geoquímica de los materiales superficiales, permite, de acuerdo con las tendencias generales de la cartografía geoquímica, extraer conclusiones que son de aplicación e interés para el conocimiento geológico y ambiental del territorio, además de para la exploración minera.The main results and conclusions of the multielemental geochemical mapping on stream sediments carried out in the Bonao-Constanza area, Cordillera Central, Dominican Republic are presented in this paper. The studied area covers 3800 km2 . The sampling density applied was 1 sample / 5 km2. A total of 684 samples were taken and 48 elements were analysed by Neutron Activation and ICPAES techniques. The area, located in the island arc of the Caribbean plate, contains important epithermal and volcanosedimentary mineralizations and has a huge potential for blind deposits. Due to the complex geology and the superimposed hydrothermal alterations, the multielemental geochemistry allows, through the analysis of patterns of spatial distribution of the elements and their geochemical associations, a better definition of anomalous zones and their assessment and meaning in relationship with their petrogenetic, geological and geochemical context. The geochemical datasets of the superficial materials allow, according with the general trends of the geochemical exploration and mapping, to get applicable and interesting conclusions for the geological, environmental and mineral exploration knowledge

    Cartografía geoquímica multielemental en sedimentos de corriente en un contexto de arco isla volcánico. Aplicación al análisis de potencialidad metalogénica en un area de la República Dominicana

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    The main results and conclusions of the multielemental geochemical mapping on stream sediments carried out in the Bonao-Constanza area, Cordillera Central, Dominican Republic are presented in this paper. The studied area covers 3800 km2 . The sampling density applied was 1 sample / 5 km2. A total of 684 samples were taken and 48 elements were analysed by Neutron Activation and ICPAES techniques. The area, located in the island arc of the Caribbean plate, contains important epithermal and volcanosedimentary mineralizations and has a huge potential for blind deposits. Due to the complex geology and the superimposed hydrothermal alterations, the multielemental geochemistry allows, through the analysis of patterns of spatial distribution of the elements and their geochemical associations, a better definition of anomalous zones and their assessment and meaning in relationship with their petrogenetic, geological and geochemical context. The geochemical datasets of the superficial materials allow, according with the general trends of the geochemical exploration and mapping, to get applicable and interesting conclusions for the geological, environmental and mineral exploration knowledge

    Evaluation of trace elements mobility from soils to sediments between the Iberian pyrite belt and the Atlantic Ocean

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    An environmental study was conducted in 193 stream sediments and 355 soil samples collected in the lower section of Guadiana River Basin to evaluate the trace elements transfer from one compartment into another. The objective was to evaluate the dispersion of Pb, Cu, Zn and other chemical elements resulting from upstream mines into the lower N-S sector of the Guadiana River Basin to the Atlantic Ocean. The area partly includes the Iberian Pyrite Belt, a known volcanogenic massive sulphide (VMS) province with important mining activity history. Median concentrations of the elements Cu, Pb, Zn, Al, As, Ba, Br, Ca, Mg, Mn and Na are generally higher in the studied sediments than in soils. Soils are normally acidic and mobility of elements is in these conditions higher. When the relations between upstream soils and downstream sediments were established, median values were higher in the upstream soils only for elements such as Co, Ni, K, Pb, Mn and Ti, probably the less mobile, and the Cu, Zn, Al, As, Ba, Br, Ca, Cr, Fe, Mg and Na have highest concentrations in the downstream sediments. Lead was considered the less mobile element and Zn the highly mobile of the base metals in the mining area of the lower Guadiana River. Dispersion of the metals, considering the studied soil and sediment samples is partially restricted to the mining areas or downstream sediments but close to the mine sources, where ore tailings and acid waters occur. Near the mouth, concentrations of As, Cu, Pb and Zn increase in relation with mining and other pollution sources. Interaction with salt water forces chemical elements precipitation from water and subsequent increase of their concentration in sediments. This may be the reason for the increase of those chemical elements concentrations in the sediment

    URBAN GEOCHEMICAL STUDIES IN EUROPE

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    Urban soil is generally contaminated to a variable degree depending on its proximity to contamination sources. Traffic is one of the main sources of urban contamination; lead (Pb) from the use of leaded petrol, zinc (Zn) and cadmium (Cd) from tyre wear, antimony (Sb) from break pads, and the platinum group Nelements (PGEs) from the wear of catalytic converters, are some typical elements that often reach high concentrations in the urban environment. Lead was also a key ingredient in white paint, and in towns with a high proportion of white wooden houses very high concentrations were found in soil. Crematoria can or have emitted mercury (Hg). Coal and heavy oil fired municipal power and heating stations emit sulphur (S), silver (Ag), vanadium (V), bromine (Br) and barium (Ba). The use of impregnated wood may have resulted in high concentrations of arsenic (As), especially in kindergartens (nursery schools) and playgrounds. Building materials (plaster and paint) may also contain high concentrations of organic contaminants, especially polychlorinated biphenyls (PCBs), which again end up in urban soil. Coal and wood burning, the use of diesel fuel, and the production of coke, all lead to the emission of polycyclic aromatic hydrocarbons (PAHs). There exist countless other sources of local contamination in towns, and there is thus every reason to be concerned about the quality of the urban environment, and the suitability of soil for sensitive land uses, such as schools, playgrounds, parks and vegetable gardens. Contaminated urban soil may contaminate indoor dust and, therefore, to an increased human exposure to toxic chemicals. Consequently, the distribution of toxic contaminants in urban soil needs to be documented and known by city administration to avoid costly mistakes in land use planning, and further spreading of highly contaminated materials. The EuroGeoSurveys ‘Geochemistry’ Expert Group during the compilation of a proposal to the Directors for a European wide urban geochemistry project, using a harmonised sampling and analytical methodology, it discovered that many urban geochemical studies have been performed in Europe by National Geological Surveys, which are not known to the wider geoscientific community. Since, the results of these studies are directly related to our quality of life, the EuroGeoSurveys ‘Geo-chemistry’ Expert Group decided to publish at least one case study from each country in a book,which will be available in the second half of 2010. A concise description of some of these studies will be given in this paper

    Cadmium (Cd) and Lead (Pb) topsoil levels and incidence of childhood leukemias

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    There are few well-established risk factors for childhood leukemias. While the frequency of childhood leukemias might be partially attributable to some diseases (accounting for a small fraction of cases) or ionizing radiation, the role of heavy metals has not been assessed. The objective of our study was to assess the potential association between levels of cadmium (Cd) and lead (PB) in soil and childhood leukemias incidence. We conducted a population-based case-control study of childhood leukaemia in Spain, covering 2897 incident cases gathered from the Spanish Registry of Childhood Tumours and including 14 Spanish Regions with a total population of 5,307,433 children (period 1996-2015). Cd and Pb bioavailable levels at every children's home address were estimated using data from the Geochemical Atlas of Spain. We used logistic regression to estimate odds ratios (ORs) and their 95% confidence intervals (95%CIs); we included as covariates: sex, rurality, employment rate and socioeconomic status. Metal levels were analysed according to two definitions: as continuous variable assuming linearity and as categorical variables to explore a potentially nonlinear association (quantiles). Increases in both Cd and Pb topsoil levels were associated with increased probability of childhood leukemias incidence. The results for the models with the continuous variables showed that a unit increase on the topsoil level was associated with an OR of 1.11 for Cd (95%CI 1.00-1.24) and an OR of 1.10 for Pb (95%CI 0.99-1.21). Our study may point towards a possible link between residential Cd and Pb topsoil levels and the probability of childhood leukemias incidence. Residing in a location with the highest concentrations of these heavy metals compared to those locations with the lowest could increase the risk around a 20%, for both Cd and Pb.This work was supported by Carlos III Health Institute: FIS 12/01416, AESI PI16CIII/00009, AESI PI19CIII/00025.S

    Stochastic Delay Accelerates Signaling in Gene Networks

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    The creation of protein from DNA is a dynamic process consisting of numerous reactions, such as transcription, translation and protein folding. Each of these reactions is further comprised of hundreds or thousands of sub-steps that must be completed before a protein is fully mature. Consequently, the time it takes to create a single protein depends on the number of steps in the reaction chain and the nature of each step. One way to account for these reactions in models of gene regulatory networks is to incorporate dynamical delay. However, the stochastic nature of the reactions necessary to produce protein leads to a waiting time that is randomly distributed. Here, we use queueing theory to examine the effects of such distributed delay on the propagation of information through transcriptionally regulated genetic networks. In an analytically tractable model we find that increasing the randomness in protein production delay can increase signaling speed in transcriptional networks. The effect is confirmed in stochastic simulations, and we demonstrate its impact in several common transcriptional motifs. In particular, we show that in feedforward loops signaling time and magnitude are significantly affected by distributed delay. In addition, delay has previously been shown to cause stable oscillations in circuits with negative feedback. We show that the period and the amplitude of the oscillations monotonically decrease as the variability of the delay time increases

    Sources, background and enrichment of lead and other elements: Lower Guadiana River

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    The lower sector of the Guadiana River Basin, located in southern Portugal and Spain, hosts soils and plants with elevated Pb, Cu and As near former and current mining sites. Two geogenic and two anthropogenic sources of Pb were identified where elevated concentrations are mostly related to the occurrence of sulphide-rich ore deposits, Volcanic Sedimentary formations and mining. These were generally reflected by the multiple regression analysis (MRA) and confirmed by isotope determinations. Nevertheless, caution was needed in interpreting statistical and isotopic results; therefore the combination of both techniques was important. Elements, such as Ca, Na, Cu and As, show enrichment in soil developed on shale, sandstone and conglomerate of Upper Devonian age belonging to the Phyllite-Quartzite Group. Lead exhibits an enrichment in soil developed on felsic volcanic rocks from the Volcanic Sedimentary Complex (VSC) of Upper Devonian-Lower Carboniferous age, which has been identified by the relationship between topsoil median values of different lithologies and grand subsoil median values. In the same soil, Fe, As, Co, Ni and Cr are depleted. Translocation of Pb to the aerial parts of plants is insignificant in all three plant species studied and analysed (Cistus ladanifer L., Thymus vulgaris, Lavandula luisieri). High Pb concentrations in soil, where Cistus ladanifer L. developed, the only representative number of species analysed, do not correspond generally to elevated Pb contents in plants, except near mine sites, where lower pH of soil, increases Pb bioavailability. The different statistical methodologies combined with Pb isotopic studies were successfully applied in the identification of Pb sources in soil and Cistus ladanifer L. plant of the Lower sector of Guadiana River basin. Therefore, rocks, mineralisations, subsoil, topsoil and plant processes were successfully integrated to understand the migration of Pb into the food chai

    ARIA 2016 : Care pathways implementing emerging technologies for predictive medicine in rhinitis and asthma across the life cycle

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    The Allergic Rhinitis and its Impact on Asthma (ARIA) initiative commenced during a World Health Organization workshop in 1999. The initial goals were (1) to propose a new allergic rhinitis classification, (2) to promote the concept of multi-morbidity in asthma and rhinitis and (3) to develop guidelines with all stakeholders that could be used globally for all countries and populations. ARIA-disseminated and implemented in over 70 countries globally-is now focusing on the implementation of emerging technologies for individualized and predictive medicine. MASK [MACVIA (Contre les Maladies Chroniques pour un Vieillissement Actif)-ARIA Sentinel NetworK] uses mobile technology to develop care pathways for the management of rhinitis and asthma by a multi-disciplinary group and by patients themselves. An app (Android and iOS) is available in 20 countries and 15 languages. It uses a visual analogue scale to assess symptom control and work productivity as well as a clinical decision support system. It is associated with an inter-operable tablet for physicians and other health care professionals. The scaling up strategy uses the recommendations of the European Innovation Partnership on Active and Healthy Ageing. The aim of the novel ARIA approach is to provide an active and healthy life to rhinitis sufferers, whatever their age, sex or socio-economic status, in order to reduce health and social inequalities incurred by the disease.Peer reviewe
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