87 research outputs found

    Isotope study of monthly rainfall and its response in the Santos Formation phreatic aquifer, Mesa de Los Santos, Santander (Colombia)

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    Mesa de Los Santos is an elevated plateau located in the Eastern Cordillera of Colombia (Andean region) in the Department of Santander (altimetric variation 300 to 1800 m a.s.l.). The region is marked by a shortage of potable surface water. The isotopic study of the rain and its relation to Los Santos Formation phreatic and fractured aquifer was carried out. Four rain stations were installed on top of the plateau (1275 to 1684 m a.s.l.) to collect monthly rainwater samples for stable isotopes. The rainwater stations recorded 1469 to 764 mm from North to South, and the seasonal patterns of stable isotopes were similar in all stations. The preliminary Local Meteoric Water Line is δ2H = 8.22×δ18O + 13.9, slightly above the GMWL with an intercept of +13.9 ‰, possibly indicating continental vapor recycling. The rain-weighted annual isotope means showed more depleted values in the southmost rain station (δ18O = −8.99 ‰, 1275 m a.s.l.). From the phreatic and fractured aquifer, 35 groundwater points were monitored bimonthly for stable isotopes (n=134) and three trends were differentiated in the isotopic content value of δ18O. Large temporal variability characterized 10 groundwater points (amplitudes greater than 1 ‰ in δ18O for each point) consistently with the seasonal behaviour of the rain, indicating flows with rapid transit on a monthly scale. 21 groundwater points showed a low temporal variability with year-round differences under 1 ‰ and presenting a spatial distribution of δ18O with enriched values towards the north (between −6.71 ‰ and −6.00 ‰) and depleted values towards the south (−8.97 ‰ to −8.14 ‰), which tends to be also consistent with the rainwater isotope distribution observed. The stability of year-round groundwater isotopic values is a sign of efficient mixing of groundwater and a slower transit. Finally, 4 groundwater points presented signs of evaporation, showing d-excess values between −6.4 ‰ and +4.3 ‰, in connection with surface water bodies that undergo evaporation before infiltration.</p

    A 50-year record of NOx and SO2 sources in precipitation in the Northern Rocky Mountains, USA

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    Ice-core samples from Upper Fremont Glacier (UFG), Wyoming, were used as proxy records for the chemical composition of atmospheric deposition. Results of analysis of the ice-core samples for stable isotopes of nitrogen (δ15N, ) and sulfur (δ34S, ), as well as and deposition rates from the late-1940s thru the early-1990s, were used to enhance and extend existing National Atmospheric Deposition Program/National Trends Network (NADP/NTN) data in western Wyoming. The most enriched δ34S value in the UFG ice-core samples coincided with snow deposited during the 1980 eruption of Mt. St. Helens, Washington. The remaining δ34S values were similar to the isotopic composition of coal from southern Wyoming. The δ15N values in ice-core samples representing a similar period of snow deposition were negative, ranging from -5.9 to -3.2 ‰ and all fall within the δ15N values expected from vehicle emissions. Ice-core nitrate and sulfate deposition data reflect the sharply increasing U.S. emissions data from 1950 to the mid-1970s

    Semantic Knowledge Influences Prewired Hedonic Responses to Odors

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    Background Odor hedonic perception relies on decoding the physicochemical properties of odorant molecules and can be influenced in humans by semantic knowledge. The effect of semantic knowledge on such prewired hedonic processing over the life span has remained unclear. Methodology/Principal Findings The present study measured hedonic response to odors in different age groups (children, teenagers, young adults, and seniors) and found that children and seniors, two age groups characterized by either low level of (children) or weak access to (seniors) odor semantic knowledge, processed odor hedonics more on the basis of their physicochemical properties. In contrast, in teenagers and young adults, who show better levels of semantic odor representation, the role of physicochemical properties was less marked. Conclusions/Significance These findings demonstrate for the first time that the biological determinants that make an odor pleasant or unpleasant are more powerful at either end of the life span

    Translation and Cross-Cultural Adaptation of a Brazilian Version of the Child Feeding Questionnaire

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    Abstract: The Child Feeding Questionnaire (CFQ) assesses parental attitudes, beliefs and practices about child feeding and obesity proneness. This research aimed to translate and to test the reliability of the CFQ and to evaluate this instrument in Brazilian families. The participants were 300 mothers and 300 children, aging from 2 to 11 years old, of both sexes. The translation, synthesis, back-translation, evaluation by an expert committee and pre-test were performed. Besides the application of questionnaire to mothers, data regarding anthropometric measurements in mothers and children was collected. The indexes of content validity index, test-retest reliability and internal consistencies were good. The parental factors Perceived parent weight, Perceived child weight, Concern about child weight, Restriction, Pressure to eat and Monitoring on child feeding were associated with overweight in childhood. In conclusion, these results highlight the validity and utility of the Brazilian version of the CFQ

    Developing healthy food preferences in preschool children through taste exposure, sensory learning and nutrition education

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    Purpose of Review: The present review was undertaken in order to summarize and evaluate recent research investigating taste exposure, sensory learning, and nutrition education interventions for promoting vegetable intake in preschool children. Recent Findings: Overall, taste exposure interventions yielded the best outcomes for increasing vegetable intake in early childhood. Evidence from sensory learning strategies such as visual exposure and experiential learning also show some success. While nutrition education remains the most common approach used in preschool settings, additional elements are needed to strengthen the educational program for increasing vegetable intake. There is a substantial gap in the evidence base to promote vegetable intake in food fussy children. Summary: The present review reveals the relative importance of different intervention strategies for promoting vegetable intake. To strengthen intervention effects for improving vegetable intake in preschool children, future research could consider integrating taste exposure and sensory learning strategies with nutrition education within the preschool curriculum
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