3,593 research outputs found

    Comparison of simulated and reconstructed variations in East African hydroclimate over the last millennium

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    The multi-decadal to centennial hydroclimate changes in East Africa over the last millennium are studied by comparing the results of forced transient simulations by six general circulation models (GCMs) with published hydroclimate reconstructions from four lakes: Challa and Naivasha in equatorial East Africa, and Masoko and Malawi in southeastern inter-tropical Africa. All GCMs simulate fairly well the unimodal seasonal cycle of precipitation in the Masoko-Malawi region, while the bimodal seasonal cycle characterizing the Challa-Naivasha region is generally less well captured by most models. Model results and lake-based hydroclimate reconstructions display very different temporal patterns over the last millennium. Additionally, there is no common signal among the model time series, at least until 1850. This suggests that simulated hydroclimate fluctuations are mostly driven by internal variability rather than by common external forcing. After 1850, half of the models simulate a relatively clear response to forcing, but this response is different between the models. Overall, the link between precipitation and tropical sea surface temperatures (SSTs) over the pre-industrial portion of the last millennium is stronger and more robust for the Challa-Naivasha region than for theMasoko-Malawi region. At the inter-annual timescale, last-millennium Challa-Naivasha precipitation is positively (negatively) correlated with western (eastern) Indian Ocean SST, while the influence of the Pacific Ocean appears weak and unclear. Although most often not significant, the same pattern of correlations between East African rainfall and the Indian Ocean SST is still visible when using the last-millennium time series smoothed to highlight centennial variability, but only in fixed-forcing simulations. This means that, at the centennial timescale, the effect of (natural) climate forcing can mask the imprint of internal climate variability in large-scale teleconnections

    Feed stream mixing in stirred tank reactors

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    Extracting more accurate position and velocity estimations using time stamping

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    Colours of fruit and vegetables and 10-year incidence of CHD

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    The colours of the edible part of fruit and vegetables indicate the presence of specific micronutrients and phytochemicals. The extent to which fruit and vegetable colour groups contribute to CHD protection is unknown. We therefore examined the associations between fruit and vegetables of different colours and their subgroups and 10-year CHD incidence. We used data from a prospective population-based cohort including 20 069 men and women aged 20–65 years who were enrolled between 1993 and 1997. Participants were free of CVD at baseline and completed a validated 178-item FFQ. Hazard ratios (HR) for the association between green, orange/yellow, red/purple, white fruit and vegetables and their subgroups with CHD were calculated using multivariable Cox proportional hazards models. During 10 years of follow-up, 245 incident cases of CHD were documented. For each 25 g/d increase in the intake of the sum of all four colours of fruit and vegetables, a borderline significant association with incident CHD was found (HR 0·98; 95 % CI 0·97, 1·01). No clear associations were found for the colour groups separately. However, each 25 g/d increase in the intake of deep orange fruit and vegetables was inversely associated with CHD (HR 0·74; 95 % CI 0·55, 1·00). Carrots, their largest contributor (60 %), were associated with a 32 % lower risk of CHD (HR 0·68; 95 % CI 0·48, 0·98). In conclusion, though no clear associations were found for the four colour groups with CHD, a higher intake of deep orange fruit and vegetables and especially carrots may protect against CH
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