7,526 research outputs found

    Visible and near-infrared observations of asteroid 2012 DA14 during its closest approach of February 15, 2013

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    Near-Earth asteroid 2012 DA14 made its closest approach on February 15, 2013, when it passed at a distance of 27,700 km from the Earth's surface. It was the first time an asteroid of moderate size was predicted to approach that close to the Earth, becoming bright enough to permit a detailed study from ground-based telescopes. Asteroid 2012 DA14 was poorly characterized before its closest approach. We acquired data using several telescopes on four Spanish observatories: the 10.4m Gran Telescopio Canarias (GTC) and the 3.6m Telescopio Nazionale Galileo (TNG), both in the El Roque de los Muchachos Observatory (ORM, La Palma); the 2.2m CAHA telescope, in the Calar Alto Observatory (Almeria); the f/3 0.77m telescope in the La Hita Observatory (Toledo); and the f/8 1.5m telescope in the Sierra Nevada Observatory (OSN, Granada). We obtained visible and near-infrared color photometry, visible spectra and time-series photometry. Visible spectra together with color photometry of 2012 DA14 show that it can be classified as an L-type asteroid, a rare spectral type with a composition similar to that of carbonaceous chondrites. The time-series photometry provides a rotational period of 8.95 +- 0.08 hours after the closest approach, and there are indications that the object suffered a spin-up during this event. The large amplitude of the light curve suggests that the object is very elongated and irregular, with an equivalent diameter of around 18m. We obtain an absolute magnitude of H_R = 24.5 +- 0.2, corresponding to H_V = 25.0 +- 0.2. The GTC photometry also gives H_V = 25.29 +- 0.14. Both values agree with the value listed at the Minor Planet Center shortly after discovery. From the absolute photometry, together with some constraints on size and shape, we compute a geometric albedo of p_V = 0.44 +- 0.20, which is slightly above the range of albedos known for L-type asteroids (0.082 - 0.405).Comment: 7 pages, 4 figures, 1 table. Accepted in A&A (June 17 2013

    Modelling the photo-Fenton oxidation of the pharmaceutical paracetamol in water including the effect of photon absorption (VRPA)

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    A new model is proposed for the photo-Fenton oxidation of water contaminants including the effect of photon absorption (volumetric rate of photon absorption, VRPA), the effect of the geometry of the reactor and the illuminated volume to total volume ratio (Ri) in the reaction system. Fe(III) was found to be the main species in the aqueous solution responsible for photon absorption provided that hydrogen peroxide was not totally consumed. Paracetamol was used as model pollutant at a concentration of 1 mM to validate the model. The illuminated part of the raceway reactor configuration (total length of 80 cm) was operated at two liquid depths (5.0 and 2.5 cm) equivalent to two irradiated reactor volumes (2 and 1 L) and using Ri ratios in the range 0.30–0.65, which changed the dark reactor volume. These values are commonly found in photo-Fenton pilot plants for water treatment and purification. The model successfully fitted the temporal evolution of the dissolved oxygen (O2) and the hydrogen peroxide (H2O2) concentrations and the evolution of the total organic carbon (TOC) in solution in both reactor geometries and for different illuminated volume to total volume ratios. The model can be easily extended to model other water contaminants and provides a robust method for process design, process control and optimization

    Global tropospheric effects of aromatic chemistry with the SAPRC-11 mechanism implemented in GEOS-Chem version 9-02

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    The Goddard Earth Observing System with chemistry (GEOS-Chem) model has been updated with the State-wide Air Pollution Research Center version 11 (SAPRC-11) aromatics chemical mechanism, with the purpose of evaluating global and regional effects of the most abundant aromatics (benzene, toluene, xylenes) on the chemical species important for tropospheric oxidation capacity. The model evaluation based on surface and aircraft observations indicates good agreement for aromatics and ozone. A comparison between scenarios in GEOS-Chem with simplified aromatic chemistry (as in the standard setup, with no ozone formation from related peroxy radicals or recycling of NOx) and with the SAPRC-11 scheme reveals relatively slight changes in ozone, the hydroxyl radical, and nitrogen oxides on a global mean basis (1&thinsp;%–4&thinsp;%), although remarkable regional differences (5&thinsp;%–20&thinsp;%) exist near the source regions. NOx decreases over the source regions and increases in the remote troposphere, due mainly to more efficient transport of peroxyacetyl nitrate (PAN), which is increased with the SAPRC aromatic chemistry. Model ozone mixing ratios with the updated aromatic chemistry increase by up to 5&thinsp;ppb (more than 10&thinsp;%), especially in industrially polluted regions. The ozone change is partly due to the direct influence of aromatic oxidation products on ozone production rates, and in part to the altered spatial distribution of NOx that enhances the tropospheric ozone production efficiency. Improved representation of aromatics is important to simulate the tropospheric oxidation.</p

    Psychoeducational proposals to promote creativity in educational contexts

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    En este trabajo se aborda la implementación de estrategias específicas y la promoción de un entorno educativo apropiado para el desarrollo de la creatividad. Se discute el constructo de creatividad desde una visión neuropsicológica y se señala la importancia de que la creatividad sea incrementada en las prácticas psicoeducativas, en ambientes desafiantes y multifacéticos. Se asume que la estimulación y experimentación precoz del pensamiento creativo en el contexto educativo son condiciones que favorecen el desarrollo de las capacidades de resolución de problemas y desafíos futuros. Se señalan prácticas de promoción de la armonía entre la investigación educativa y la intervención psicológica, en relación con el desarrollo de capacidades y actitudes que estimulan el pensamiento y el potencial creativo

    Testing the theory of immune selection in cancers that break the rules of transplantation

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    Modification of cancer cells likely to reduce their immunogenicity, including loss or down-regulation of MHC molecules, is now well documented and has become the main support for the concept of immune surveillance. The evidence that these modifications, in fact, result from selection by the immune system is less clear, since the possibility that they may result from reorganized metabolism associated with proliferation or from cell de-differentiation remains. Here, we (a) survey old and new transplantation experiments that test the possibility of selection and (b) survey how transmissible tumours of dogs and Tasmanian devils provide naturally evolved tests of immune surveillance

    Socio-geographical disparities of obesity and excess weight in adults in Spain: insights from the ENE-COVID study

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    Background: In Spain, differences in the prevalence of obesity and excess weight according to sex and sociodemographic factors have been described at the national level, although current data do not allow to delve into geographical differences for these conditions. The aim was to estimate national and regional prevalences of adult obesity and excess weight in Spain by sex and sociodemographic characteristics, and to explore difference sources of inequalities in its distribution, as well as its geographical pattern. Method: ENE-COVID study was a nationwide representative seroepidemiological survey with 57,131 participants. Residents in 35,893 households were selected from municipal rolls using a two-stage random sampling stratified by province and municipality size (April-June 2020). Participants (77.0% of contacted individuals) answered a questionnaire which collected self-reported weight and height, as well as different socioeconomic variables, that allowed estimating crude and standardized prevalences of adult obesity and excess weight. Results: Crude prevalences of obesity and excess weight were higher in men (obesity: 19.3% vs. 18.0%; excess weight: 63.7% vs. 48.4%), while severe obesity was more prevalent in women (4.5% vs. 5.3%). These prevalences increased with age and disability, and decreased with education, census tract income and municipality size. Differences by educational level, relative census income, nationality or disability were clearly higher among women. Obesity by province ranged 13.3-27.4% in men and 11.4-28.1% in women; excess weight ranged 57.2-76.0% in men and 38.9-59.5% in women. The highest prevalences were located in the southern half of the country and some north-western provinces. Sociodemographic characteristics only explained a small part of the observed geographical variability (25.2% obesity). Conclusion: Obesity and overweight have a high prevalence in Spain, with notable geographical and sex differences. Socioeconomic inequalities are stronger among women. The observed geographical variability suggests the need to implement regional and local interventions to effectively address this public health problem.This study was supported by Spanish Ministry of Health, Institute of Health Carlos III, and Spanish National Health System.S

    Diagnosis of Transient/Latent HPV Infections - A Point of View!

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    © 2018 IMSS Diagnosis of transient/latent HPV infections requires a rethinking of ideas concerning the host virus relationship. With this in mind, we address several concepts, such as mutualism and commensalism, to understand better the different stages of development, in addition to briefly covering current methods of detection. We suggest analyzing molecules related to the innate immune response for earlier diagnosis

    Transiting exoplanets from the CoRoT space mission VIII. CoRoT-7b: the first Super-Earth with measured radius

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    We report the discovery of very shallow (DF/F = 3.4 10-4), periodic dips in the light curve of an active V = 11.7 G9V star observed by the CoRoT satellite, which we interpret as due to the presence of a transiting companion. We describe the 3-colour CoRoT data and complementary ground-based observations that support the planetary nature of the companion. Methods. We use CoRoT color information, good angular resolution ground-based photometric observations in- and out- of transit, adaptive optics imaging, near-infrared spectroscopy and preliminary results from Radial Velocity measurements, to test the diluted eclipsing binary scenarios. The parameters of the host star are derived from optical spectra, which were then combined with the CoRoT light curve to derive parameters of the companion. We examine carefully all conceivable cases of false positives, and all tests performed support the planetary hypothesis. Blends with separation larger than 0.40 arcsec or triple systems are almost excluded with a 8 10-4 risk left. We conclude that, as far as we have been exhaustive, we have discovered a planetary companion, named CoRoT-7b, for which we derive a period of 0.853 59 +/- 3 10-5 day and a radius of Rp = 1.68 +/- 0.09 REarth. Analysis of preliminary radial velocity data yields an upper limit of 21 MEarth for the companion mass, supporting the finding. CoRoT-7b is very likely the first Super-Earth with a measured radius.Comment: Accepted in Astronomy and Astrophysics; typos and language corrections; version sent to the printer w few upgrade

    Severity-Related Changes of Bronchial Microbiome in Chronic Obstructive Pulmonary Disease

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    Bronchial colonization by potentially pathogenic microorganisms (PPMs) is often demonstrated in chronic obstructive pulmonary disease (COPD), but culture-based techniques identify only a portion of the bacteria in mucosal surfaces. The aim of the study was to determine changes in the bronchial microbiome of COPD associated with the severity of the disease. The bronchial microbiome of COPD patients was analyzed by 16S rRNA gene amplification and pyrosequencing in sputum samples obtained during stable disease. Seventeen COPD patients were studied (forced expiratory volume in the first second expressed as a percentage of the forced vital capacity [FEV1%] median, 35.0%; interquartile range [IQR], 31.5 to 52.0), providing a mean of 4,493 (standard deviation [SD], 2,598) sequences corresponding to 47 operational taxonomic units (OTUs) (SD, 17) at a 97% identity level. Patients were dichotomized according to their lung function as moderate to severe when their FEV1% values were over the median and as advanced when FEV1% values were lower. The most prevalent phyla in sputum were Proteobacteria (44%) and Firmicutes (16%), followed by Actinobacteria (13%). A greater microbial diversity was found in patients with moderate-to-severe disease, and alpha diversity showed a statistically significant decrease in patients with advanced disease when assessed by Shannon (ρ = 0.528; P = 0.029, Spearman correlation coefficient) and Chao1 (ρ = 0.53; P = 0.028, Spearman correlation coefficient) alpha-diversity indexes. The higher severity that characterizes advanced COPD is paralleled by a decrease in the diversity of the bronchial microbiome, with a loss of part of the resident flora that is replaced by a more restricted microbiota that includes PPMs
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