6 research outputs found

    Limnological, sedimentological, mineralogical and geological data of 76 aquatic ecosystems of the northern Neotropics (from Yucatán Peninsula Mexico to Nicaragua) sampled in 2013

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    Here, we present 23 water physical (temperature, dissolved oxygen, pH, conductivity) and chemical (major anions Cl-, SO42-, CO32-, HCO3- and cations Ca2+, K+, Mg2+, Na+), sedimentological (total carbon (TC), total inorganic carbon (TIC), total organic carbon (TOC), total nitrogen (TN)), mineralogical (quartz, carbonate, phyllosilicates and feldspars) and geological (altitude, bedrock type and age of sediments) variables of aquatic systems of the Northern Neotropical region. Sampling was conducted in 76 aquatic systems during July-October 2013, coinciding with the rainy season in the region. Sampling sites are located on the Yucatán Peninsula Mexico (n=28), Guatemala (n=26), El Salvador (n=14), Honduras (n=5) and Nicaragua (n=3). We aim to identify limnological regions based on the measured variables and to infer the influence of geodiversity in observed patterns. Water physical and chemical variables were measured in situ with a WTW Multi Set 350i multiparameter probe at a water depth of 0.5 m. Water samples for analysis of major anions and cations were collected at water depths of 0.5 m below surface. TC and TN in sediments contents were determined by combustion with a LECO TruSpec Macro CHN analyzer. TIC was quantified with a Woesthoff Carmhograph C-16. TOC was calculated by subtracting TIC from TC. Qualitative and semi-quantitative mineralogical compounds were examined by x-ray diffraction with a RIGAKU Miniflex600. ArcGIS software was used to identify geological attributes of sampling sites such as bedrock and age of sediments. Altitude, latitude, and longitude were determined with the navigator Garmin GPSmap 60c

    Genetic modification of the effect of maternal household air pollution exposure on birth weight in Guatemalan newborns

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    Low birth weight is associated with exposure to air pollution during pregnancy. The purpose of this study was to evaluate whether null polymorphisms of Glutathione S-transferases (GSTs), specifically GSTM1 and GSTT1 genes in infants or mothers, modifies the association between high exposures to household air pollution (HAP) from cooking fires and birth weight. Pregnant women in rural Guatemala were randomized to receive a chimney stove or continue to use open fires for cooking. Newborns were measured within 48 hours of birth. 132 mother-infant pairs provided infant genotypes (n=130) and/or maternal genotypes (n=116). Maternal null GSTM1 was associated with a 144 gram (95% CI: -291, 1) and combined maternal/infant null GSTT1 was associated with a 155 gram (95% CI -303, -8) decrease in birth weight. Although there was a trend toward higher birth weights with increasing number of expressed GST genes, the effect modification by chimney stove use was not demonstrated

    Trabajos Especiales de Grado de ingeniería Geológica 1990-1999

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    Growing knowledge: an overview of Seed Plant diversity in Brazil

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    Growing knowledge: an overview of Seed Plant diversity in Brazil

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    Abstract An updated inventory of Brazilian seed plants is presented and offers important insights into the country's biodiversity. This work started in 2010, with the publication of the Plants and Fungi Catalogue, and has been updated since by more than 430 specialists working online. Brazil is home to 32,086 native Angiosperms and 23 native Gymnosperms, showing an increase of 3% in its species richness in relation to 2010. The Amazon Rainforest is the richest Brazilian biome for Gymnosperms, while the Atlantic Rainforest is the richest one for Angiosperms. There was a considerable increment in the number of species and endemism rates for biomes, except for the Amazon that showed a decrease of 2.5% of recorded endemics. However, well over half of Brazillian seed plant species (57.4%) is endemic to this territory. The proportion of life-forms varies among different biomes: trees are more expressive in the Amazon and Atlantic Rainforest biomes while herbs predominate in the Pampa, and lianas are more expressive in the Amazon, Atlantic Rainforest, and Pantanal. This compilation serves not only to quantify Brazilian biodiversity, but also to highlight areas where there information is lacking and to provide a framework for the challenge faced in conserving Brazil's unique and diverse flora
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