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- Arneth, Almut, et al.
(författare)
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From biota to chemistry and climate: towards a comprehensive description of trace gas exchange between the biosphere and atmosphere
- 2010
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Ingår i: Biogeosciences. - 1726-4189. ; 7:1, s. 121-149
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Forskningsöversikt (refereegranskat)abstract
- Exchange of non-CO2 trace gases between the land surface and the atmosphere plays an important role in atmospheric chemistry and climate. Recent studies have highlighted its importance for interpretation of glacial-interglacial ice-core records, the simulation of the pre-industrial and present atmosphere, and the potential for large climate-chemistry and climate-aerosol feedbacks in the coming century. However, spatial and temporal variations in trace gas emissions and the magnitude of future feedbacks are a major source of uncertainty in atmospheric chemistry, air quality and climate science. To reduce such uncertainties Dynamic Global Vegetation Models (DGVMs) are currently being expanded to mechanistically represent processes relevant to non-CO2 trace gas exchange between land biota and the atmosphere. In this paper we present a review of important non-CO2 trace gas emissions, the state-of-the-art in DGVM modelling of processes regulating these emissions, identify key uncertainties for global scale model applications, and discuss a methodology for model integration and evaluation.
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- Strand, Tor A., et al.
(författare)
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Cobalamin and folate status predicts mental development scores in North Indian children 12-18 mo of age
- 2013
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Ingår i: American Journal of Clinical Nutrition. - : Elsevier BV. - 0002-9165 .- 1938-3207. ; 97:2, s. 310-317
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Tidskriftsartikel (refereegranskat)abstract
- Background: Micronutrient deficiencies can affect cognitive function. Many young children in low-and middle-income countries have inadequate cobalamin (vitamin B-12) status. Objective: The objective was to measure the association of plasma concentrations of folate, cobalamin, total homocysteine, and methylmalonic acid with cognitive performance at 2 occasions, 4 mo apart, in North Indian children aged 12-18 mo. Design: Bayley Scales of Infant Development II were used to assess cognition. In multiple regression models adjusted for several potential confounders, we measured the association between biomarkers for folate and cobalamin status and psychomotor or mental development scores on the day of blood sampling and 4 mo thereafter. Results: Each 2-fold increment in plasma cobalamin concentration was associated with a significant increment in the mental development index score of 1.3 (95% CI: 0.2, 2.4; P = 0.021). Furthermore, each 2-fold increment in homocysteine or methylmalonic acid concentration was associated with a decrement in mental development index score of 2.0 (95% CI: 0.5, 3.4; P = 0.007) or 1.1 (95% CI: 0.3, 1.8; P = 0.004) points, respectively. Plasma folate concentration was significantly and independently associated with mental development index scores only when children with poor cobalamin status were excluded, ie, in those who had cobalamin concentrations below the 25th percentile. None of these markers was associated with psychomotor scores in the multiple regression models. Conclusions: Cobalamin and folate status showed a statistically significant association with cognitive performance. Given the high prevalence of deficiencies in these nutrients, folate and cobalamin supplementation trials are required to measure any beneficial effect on cognition. The study was registered at www.clinicaltrials.gov under the identifier number NCT00272116. Am J Clin Nutr 2013;97:310-7.
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