497 research outputs found

    Drug use among students of the Faculty of Medical Sciences of the National Autonomous University of Nicaragua, Leon, Nicaragua

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    Se busco caracterizar a estudiantes de la Facultad de Ciencias Médicas de la UNAN León y su relación con drogas licitas e ilícitas, mediante un estudio descriptivo transversal realizado en el año 2008 en la Ciudad de León, en Nicaragua. Se utilizó un cuestionario anónimo autoaplicado SAMSHA (Substance Abuse and Mental Health) adaptado a la realidad Nicaragüense, el que fue respondido por un total de 954 estudiantes entre 17 y 35 años, de ambos sexos, de las carreras profesionales de dicha facultad. Encontrándose 52,6% de uso de alcohol, 25,3% de Tabaco, 48,7% de Medicamentos y 2,6% de Cocaína. Se propone profundizar este tema con nuevos estudios para poder dirigir mejor las acciones de intervención.Os objetivos desta pesquisa foram a busca pela caracterização de estudantes da Faculdade de Ciências Medicas da UNAN, em León, e sua relação com drogas licitas e ilícitas, mediante estudo descritivo transversal, realizado no ano 2008, na Cidade de León, Nicarágua. Utilizou-se questionário autoaplicado SAMSHA (Substance Abuse and Mental Health) sem identificação dos sujeitos, adaptado à realidade nicaraguense, o qual foi respondido por 954 estudantes, entre 17 e 35 anos, de ambos os sexos, das carreiras profissionais dessa faculdade. Encontrou-se, como resultados, 52,6% de uso de álcool, 25,3% de tabaco, 48,7% de medicamentos e 2,6% de cocaína. Propõe-se aprofundar a temática em questão, com novos estudos, para melhor dirigir as ações de intervenção no contexto universitário.The aim of this study was to characterize the relationships of students of the Faculty of Medical Sciences of UNAN León, with licit and illicit drugs. This was accomplished by means of a traversal, descriptive study carried out in the year 2008 in the City of León, Nicaragua. The SAMSHA (Substance Abuse and Mental Health Services Administration) questionnaire, adapted for the Nicaraguan context, was applied anonymously. The questionnaire was completed by a total of 954 students, between 17 and 35 years old, of both sexes. It was found that 52.6% of the students used alcohol, 25.3% tobacco, 48.7% medication and 2.6% cocaine. It is necessary to develop other studies to guide prevention and intervention in the university context

    Caracterización de tres ecotipos de quinua " chenopodium quinoa willd" mediante técnicas agroecológicas, en dos zonas agroclimatologicamente diferentes del departamento de Cundinamarca

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    El presente artículo recoge los resultados de una investigación que tuvo en cuenta las nuevas tendencias de comercialización y producción agrícola que se rigen bajo los términos de productividad, calidad y competitividad; la inexistencia de variedades de quinua que ofrezcan al agricultor características ideales de cultivo (adaptación al medio y buen rendimiento); la selectividad genética producto de la participación de factores ambientales y la intervención del hombre, que de alguna manera ha orientado su evolución hacia las variables más convenientes para su utilización agrícola. Teniendo en cuenta los antecedentes descritos, se realizó la investigación con el objeto de caracterizar tres ecotipos de quinua “Chenopodium quinoa willd.” en dos zonas agroclimatológicamente diferentes y donde se evaluó y comparó su comportamiento, desarrollo, rendimiento y adaptabilidad

    Quaternary structure of a G-protein coupled receptor heterotetramer in complex with Gi and Gs

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    Background: G-protein-coupled receptors (GPCRs), in the form of monomers or homodimers that bind heterotrimeric G proteins, are fundamental in the transfer of extracellular stimuli to intracellular signaling pathways. Different GPCRs may also interact to form heteromers that are novel signaling units. Despite the exponential growth in the number of solved GPCR crystal structures, the structural properties of heteromers remain unknown. Results: We used single-particle tracking experiments in cells expressing functional adenosine A1-A2A receptors fused to fluorescent proteins to show the loss of Brownian movement of the A1 receptor in the presence of the A2A receptor, and a preponderance of cell surface 2:2 receptor heteromers (dimer of dimers). Using computer modeling, aided by bioluminescence resonance energy transfer assays to monitor receptor homomerization and heteromerization and G-protein coupling, we predict the interacting interfaces and propose a quaternary structure of the GPCR tetramer in complex with two G proteins. Conclusions: The combination of results points to a molecular architecture formed by a rhombus-shaped heterotetramer, which is bound to two different interacting heterotrimeric G proteins (Gi and Gs). These novel results constitute an important advance in understanding the molecular intricacies involved in GPCR function

    Multilocus Bayesian Estimates of Intra-Oceanic Genetic Differentiation, Connectivity, and Admixture in Atlantic Swordfish (Xiphias gladius L.)

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    Horizontal Branch Stars: The Interplay between Observations and Theory, and Insights into the Formation of the Galaxy

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    We review HB stars in a broad astrophysical context, including both variable and non-variable stars. A reassessment of the Oosterhoff dichotomy is presented, which provides unprecedented detail regarding its origin and systematics. We show that the Oosterhoff dichotomy and the distribution of globular clusters (GCs) in the HB morphology-metallicity plane both exclude, with high statistical significance, the possibility that the Galactic halo may have formed from the accretion of dwarf galaxies resembling present-day Milky Way satellites such as Fornax, Sagittarius, and the LMC. A rediscussion of the second-parameter problem is presented. A technique is proposed to estimate the HB types of extragalactic GCs on the basis of integrated far-UV photometry. The relationship between the absolute V magnitude of the HB at the RR Lyrae level and metallicity, as obtained on the basis of trigonometric parallax measurements for the star RR Lyrae, is also revisited, giving a distance modulus to the LMC of (m-M)_0 = 18.44+/-0.11. RR Lyrae period change rates are studied. Finally, the conductive opacities used in evolutionary calculations of low-mass stars are investigated. [ABRIDGED]Comment: 56 pages, 22 figures. Invited review, to appear in Astrophysics and Space Scienc

    Citric acid wastewater as electron donor for biological sulfate reduction

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    Citrate-containing wastewater is used as electron donor for sulfate reduction in a biological treatment plant for the removal of sulfate. The pathway of citrate conversion coupled to sulfate reduction and the microorganisms involved were investigated. Citrate was not a direct electron donor for the sulfate-reducing bacteria. Instead, citrate was fermented to mainly acetate and formate. These fermentation products served as electron donors for the sulfate-reducing bacteria. Sulfate reduction activities of the reactor biomass with acetate and formate were sufficiently high to explain the sulfate reduction rates that are required for the process. Two citrate-fermenting bacteria were isolated. Strain R210 was closest related to Trichococcus pasteurii (99.5% ribosomal RNA (rRNA) gene sequence similarity). The closest relative of strain S101 was Veillonella montepellierensis with an rRNA gene sequence similarity of 96.7%. Both strains had a complementary substrate range

    Earliest evidence of pollution by heavy metals in archaeological sites

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    Homo species were exposed to a new biogeochemical environment when they began to occupy caves. Here we report the first evidence of palaeopollution through geochemical analyses of heavy metals in four renowned archaeological caves of the Iberian Peninsula spanning the last million years of human evolution. Heavy metal contents reached high values due to natural (guano deposition) and anthropogenic factors (e.g. combustion) in restricted cave environments. The earliest anthropogenic pollution evidence is related to Neanderthal hearths from Gorham's Cave (Gibraltar), being one of the first milestones in the so-called “Anthropocene”. According to its heavy metal concentration, these sediments meet the present-day standards of “contaminated soil”. Together with the former, the Gibraltar Vanguard Cave, shows Zn and Cu pollution ubiquitous across highly anthropic levels pointing to these elements as potential proxies for human activities. Pb concentrations in Magdalenian and Bronze age levels at El Pirulejo site can be similarly interpreted. Despite these high pollution levels, the contaminated soils might not have posed a major threat to Homo populations. Altogether, the data presented here indicate a long-term exposure of Homo to these elements, via fires, fumes and their ashes, which could have played certain role in environmental-pollution tolerance, a hitherto neglected influence.Francisco J. Jiménez Palacios and to the Analytical Chemistry Department (Sevilla University) are gratefully acknowledged for their help in the use of Carbolite electric oven. A.G.-A. was supported by a Marie Curie Intra-European Fellowship of the 7th Framework Programme for Research, Technological Development and Demonstration (European Commission). R.B. is a Beatriu de Pinós-A post-doctoral fellowship recipient (Generalitat de Catalunya and COFUND Marie Curie Actions, EU-FP7). This work also was partially financed by projects 19434/PI/14 Fundación Séneca, HARP2013-44269P, CGL-BOS-2012-34717, CGL2012-38434-C03-03 and CGL2012-38358 Ministerio de Economía y Competitividad, 2014 SGR 900 and 2014/100573 Generalitat de Catalunya-AGAUR, RNM 432 Research Group 179 (Junta de Andalucia) and MEXT-Japan

    Reproductive aspects of the oceanic whitetip shark, Carcharhinus longimanus (Elasmobranchii: Carcharhinidae), in the equatorial and southwestern Atlantic Ocean

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    The present study sought to study the reproductive biology of the oceanic whitetip shark, Carcharhinus longimanus, in the equatorial and southwestern Atlantic Ocean. A total of 234 specimens were collected as bycatch during pelagic longline fisheries targeting tunas and swordfish, between December 2003 and December 2010. The fishing area was located between latitudes 10N and 35S and longitudes 3E and 40W. Of the 234 individuals sampled, 118 were females (with sizes ranging from 81 to 227 cm TL, total length) and 116 males (ranging from 80 to 242 cm TL). The reproductive stages of the females were classed as immature, mature, preovulatory and pregnant, while males were divided into immature, maturing and mature. The size at maturity for females was estimated at 170.0 cm TL, while that for males was between 170.0 and 190.0 cm TL. Ovarian fecundity ranged from 1 to 10 follicles and uterine fecundity from 1 to 10 embryos. The reproductive cycle of this species is most likely biennial, with parturition occurring once every two years.info:eu-repo/semantics/publishedVersio

    Network Structure of Vertebrate Scavenger Assemblages at the Global Scale: Drivers and Ecosystem Functioning Implications

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    The organization of ecological assemblages has important implications for ecosystem functioning, but little is known about how scavenger communities organize at the global scale. Here, we test four hypotheses on the factors affecting the network structure of terrestrial vertebrate scavenger assemblages and its implications on ecosystem functioning. We expect scavenger assemblages to be more nested (i.e. structured): 1) in species‐rich and productive regions, as nestedness has been linked to high competition for carrion resources, and 2) regions with low human impact, because the most efficient carrion consumers that promote nestedness are large vertebrate scavengers, which are especially sensitive to human persecution. 3) We also expect climatic conditions to affect assemblage structure, because some scavenger assemblages have been shown to be more nested in colder months. Finally, 4) we expect more organized assemblages to be more efficient in the consumption of the resource. We first analyzed the relationship between the nestedness of the scavenger assemblages and climatic variables (i.e. temperature, precipitation, temperature variability and precipitation variability), ecosystem productivity and biomass (i.e. NDVI) and degree of human impact (i.e. human footprint) using 53 study sites in 22 countries across five continents. Then, we related structure (i.e. nestedness) with its function (i.e. carrion consumption rate). We found a more nested structure for scavenger assemblages in regions with higher NDVI values and lower human footprint. Moreover, more organized assemblages were more efficient in the consumption of carrion. However, our results did not support the prediction that the structure of the scavenger assemblages is directly related to climate. Our findings suggest that the nested structure of vertebrate scavenger assemblages affects its functionality and is driven by anthropogenic disturbance and ecosystem productivity worldwide. Disarray of scavenger assemblage structure by anthropogenic disturbance may lead to decreases in functionality of the terrestrial ecosystems via loss of key species and trophic facilitation processes
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