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- Reeves, Jessica M., et al.
(författare)
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Palaeoenvironmental change in tropical Australasia over the last 30,000 years - a synthesis by the OZ-INTIMATE group
- 2013
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Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791 .- 1873-457X. ; 74, s. 97-114
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Tidskriftsartikel (refereegranskat)abstract
- The tropics are the major source of heat and moisture for the Australasian region. Determining the tropics' response over time to changes in climate forcing mechanisms, such as summer insolation, and the effects of relative sea level on exposed continental shelves during the Last Glacial period, is an ongoing process of re-evaluation. We present a synthesis of climate proxy data from tropical Australasia spanning the last 30,000 years that incorporates deep sea core, coral, speleothem, pollen, charcoal and terrestrial sedimentary records. Today, seasonal variability is governed largely by the annual migration of the inter-tropical convergence zone (ITCZ), influencing this region most strongly during the austral summer. However, the position of the ITCZ has varied through time. Towards the end of Marine Isotope Stage (MIS) 3, conditions were far wetter throughout the region, becoming drier first in the south. Universally cooler land and sea-surface temperature (SST) were characteristic of the Last Glacial Maximum, with drier conditions than previously, although episodic wet periods are noted in the fluvial records of northern Australia. The deglacial period saw warming first in the Coral Sea and then the Indonesian seas, with a pause in this trend around the time of the Antarctic Cold Reversal (c. 14.5 ka), coincident with the flooding of the Sunda Shelf. Wetter conditions occurred first in Indonesia around 17 ka and northern Australia after 14 ka. The early Holocene saw a peak in marine SST to the northwest and northeast of Australia. Modern vegetation was first established on Indonesia, then progressively south and eastward to NE Australia. Flores and the Atherton Tablelands show a dry period around 11.6 ka, steadily becoming wetter through the early Holocene. The mid-late Holocene was punctuated by millennial-scale variability, associated with the El Nino-Southern Oscillation; this is evident in the marine, coral, speleothem and pollen records of the region.
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- Vandevijvere, Stefanie, et al.
(författare)
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Evaluation of food and nutrient intake assessment using concentration biomarkers in European adolescents from the HELENA study
- 2013
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Ingår i: British Journal of Nutrition. - 0007-1145 .- 1475-2662. ; 109:4, s. 736-747
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Tidskriftsartikel (refereegranskat)abstract
- Accurate food and nutrient intake assessment is essential for investigating diet-disease relationships. In the present study, food and nutrient intake assessment among European adolescents using 24 h recalls (mean of two recalls) and a FFQ (separately and the combination of both) were evaluated using concentration biomarkers. Biomarkers included were vitamin C, β-carotene, DHA+EPA, vitamin B12 (cobalamin and holo-transcobalamin) and folate (erythrocyte folate and plasma folate). For the evaluation of the food intake assessment 390 adolescents were included, while 697 were included for the nutrient intake assessment evaluation. Spearman rank and Pearson correlations, and validity coefficients, which are correlations between intake estimated and habitual true intake, were calculated. Correlations were higher between frequency of food consumption (from the FFQ) and concentration biomarkers than between mean food intake (from the recalls) and concentration biomarkers, especially for DHA+EPA (r 0·35 v. r 0·27). Most correlations were higher among girls than boys. For boys, the highest validity coefficients were found for frequency of fruit consumption (0·88) and for DHA+EPA biomarker (0·71). In girls, the highest validity coefficients were found for fruit consumption frequency (0·76), vegetable consumption frequency (0·74), mean fruit intake (0·90) and DHA+EPA biomarker (0·69). After exclusion of underreporters, correlations slightly improved. Correlations between usual food intakes, adjusted for food consumption frequency, and concentration biomarkers were higher than correlations between mean food intakes and concentration biomarkers. In conclusion, two non-consecutive 24 h recalls in combination with a FFQ seem to be appropriate to rank subjects according to their usual food intake
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- Vyncke, K, et al.
(författare)
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Validation of the Diet Quality Index for Adolescents by comparison with biomarkers, nutrient and food intakes : the HELENA study
- 2013
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Ingår i: British Journal of Nutrition. - 0007-1145 .- 1475-2662. ; 109:11, s. 2067-2078
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Tidskriftsartikel (refereegranskat)abstract
- Food-based dietary guidelines (FBDG) aim to address the nutritional requirements at population level in order to prevent diseases and promote a healthy lifestyle. Diet quality indices can be used to assess the compliance with these FBDG. The present study aimed to investigate whether the newly developed Diet Quality Index for Adolescents (DQI-A) is a good surrogate measure for adherence to FBDG, and whether adherence to these FBDG effectively leads to better nutrient intakes and nutritional biomarkers in adolescents. Participants included 1804 European adolescents who were recruited in the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) Study. Dietary intake was assessed by two, non-consecutive 24 h recalls. A DQI-A score, considering the components' dietary quality, diversity and equilibrium, was calculated. Associations between the DQI-A and food and nutrient intakes and blood concentration biomarkers were investigated using multilevel regression analysis corrected for centre, age and sex. DQI-A scores were associated with food intake in the expected direction: positive associations with nutrient-dense food items, such as fruits and vegetables, and inverse associations with energy-dense and low-nutritious foods. On the nutrient level, the DQI-A was positively related to the intake of water, fibre and most minerals and vitamins. No association was found between the DQI-A and total fat intake. Furthermore, a positive association was observed with 25-hydroxyvitamin D, holo-transcobalamin and n-3 fatty acid serum levels. The present study has shown good validity of the DQI-A by confirming the expected associations with food and nutrient intakes and some biomarkers in blood.
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