692 resultados para diet surveys
Resumo:
This paper considers the potential contribution of secondary quantitative analyses of large scale surveys to the investigation of 'other' childhoods. Exploring other childhoods involves investigating the experience of young people who are unequally positioned in relation to multiple, embodied, identity locations, such as (dis)ability, 'class', gender, sexuality, ethnicity and race. Despite some possible advantages of utilising extensive databases, the paper outlines a number of methodological problems with existing surveys which tend to reinforce adultist and broader hierarchical social relations. It is contended that scholars of children's geographies could overcome some of these problematic aspects of secondary data sources by endeavouring to transform the research relations of large scale surveys. Such endeavours would present new theoretical, ethical and methodological complexities, which are briefly considered.
Resumo:
To provide reliable estimates for mapping soil properties for precision agriculture requires intensive sampling and costly laboratory analyses. If the spatial structure of ancillary data, such as yield, digital information from aerial photographs, and soil electrical conductivity (EC) measurements, relates to that of soil properties they could be used to guide the sampling intensity for soil surveys. Variograins of permanent soil properties at two study sites on different parent materials were compared with each other and with those for ancillary data. The ranges of spatial dependence identified by the variograms of both sets of properties are of similar orders of magnitude for each study site, Maps of the ancillary data appear to show similar patterns of variation and these seem to relate to those of the permanent properties of the soil. Correlation analysis has confirmed these relations. Maps of kriged estimates from sub-sampled data and the original variograrns showed that the main patterns of variation were preserved when a sampling interval of less than half the average variogram range of ancillary data was used. Digital data from aerial photographs for different years and EC appear to show a more consistent relation with the soil properties than does yield. Aerial photographs, in particular those of bare soil, seem to be the most useful ancillary data and they are often cheaper to obtain than yield and EC data.
Resumo:
We present here the results of a large-scale diachronic palaeodietary (carbon and nitrogen isotopic measurements of bone collagen) study of humans and animals from a single site, the city of York (U.K.) dating from the Roman period to the early 19th century The human sample comprises 313 burials from the cemeteries of Trentholme Drive and Blossom Street (Roman), Belle Vue House (Anglo-Saxon), Fishergate (High and Later Medieval), and All Saints, Pavement (Later and Post-Medieval). In addition, 145 samples of mammal, fish and bird bone from the sites of Tanner Row and Fishergate were analyzed. The isotope data suggest dietary variation between all archaeological periods, although the most significant change was the introduction of significant quantities of marine foods in the Medieval periods. These are first evident in the diet of a small group of individuals from the High Medieval cemetery at Fishergate, although they were consumed almost universally in the following periods. The human isotope values are also remarkable due to unusually elevated delta N-15 ratios that are not sufficiently explained by the comparably small enrichment in C-13 that accompanies them. We discuss the possible reasons behind this and the archaeological significance of the data set.
Resumo:
We present the results of stable carbon and nitrogen isotope analysis of bone collagen for 155 individuals buried at the Later Medieval (13th to early 16th century AD) Gilbertine priory of St. Andrew, Fishergate in the city of York (UK). The data show significant variation in the consumption of marine foods between males and females as well as between individuals buried in different areas of the priory. Specifically, individuals from the crossing of the church and the cloister garth had consumed significantly less marine protein than those from other locations. Isotope data for four individuals diagnosed with diffuse idiopathic skeletal hyperostosis (DISH) are consistent with a diet rich in animal protein. We also observe that isotopic signals of individuals with perimortem sharp force trauma are unusual in the context of the Fishergate dataset. We discuss possible explanations for these patterns and suggest that there may have been a specialist hospital or a local tradition of burying victims of violent conflict at the priory. The results demonstrate how the integration of archaeological, osteological, and isotopic data can provide novel information about Medieval burial and society.
Resumo:
Habitat loss poses a major threat to biodiversity, and species-specific extinction risks are inextricably linked to life-history characteristics. This relationship is still poorly documented for many functionally important taxa, and at larger continental scales. With data from five replicated field studies from three countries, we examined how species richness of wild bees varies with habitat patch size. We hypothesized that the form of this relationship is affected by body size, degree of host plant specialization and sociality. Across all species, we found a positive species–area slope (z ¼ 0.19), and species traits modified this relationship. Large-bodied generalists had a lower z value than small generalists. Contrary to predictions, small specialists had similar or slightly lower z value compared with large specialists, and small generalists also tended to be more strongly affected by habitat loss as compared with small specialists. Social bees were negatively affected by habitat loss (z ¼ 0.11) irrespective of body size. We conclude that habitat loss leads to clear shifts in the species composition of wild bee communities.
Resumo:
The development of high throughput techniques ('chip' technology) for measurement of gene expression and gene polymorphisms (genomics), and techniques for measuring global protein expression (proteomics) and metabolite profile (metabolomics) are revolutionising life science research, including research in human nutrition. In particular, the ability to undertake large-scale genotyping and to identify gene polymorphisms that determine risk of chronic disease (candidate genes) could enable definition of an individual's risk at an early age. However, the search for candidate genes has proven to be more complex, and their identification more elusive, than previously thought. This is largely due to the fact that much of the variability in risk results from interactions between the genome and environmental exposures. Whilst the former is now very well defined via the Human Genome Project, the latter (e.g. diet, toxins, physical activity) are poorly characterised, resulting in inability to account for their confounding effects in most large-scale candidate gene studies. The polygenic nature of most chronic diseases offers further complexity, requiring very large studies to disentangle relatively weak impacts of large numbers of potential 'risk' genes. The efficacy of diet as a preventative strategy could also be considerably increased by better information concerning gene polymorphisms that determine variability in responsiveness to specific diet and nutrient changes. Much of the limited available data are based on retrospective genotyping using stored samples from previously conducted intervention trials. Prospective studies are now needed to provide data that can be used as the basis for provision of individualised dietary advice and development of food products that optimise disease prevention. Application of the new technologies in nutrition research offers considerable potential for development of new knowledge and could greatly advance the role of diet as a preventative disease strategy in the 21st century. Given the potential economic and social benefits offered, funding for research in this area needs greater recognition, and a stronger strategic focus, than is presently the case. Application of genomics in human health offers considerable ethical and societal as well as scientific challenges. Economic determinants of health care provision are more likely to resolve such issues than scientific developments or altruistic concerns for human health.
Resumo:
Eight Jersey cows were used in two balanced 4 x 4 Latin Squares to investigate the effects of replacement of dietary starch with non-forage fibre on productivity, diet digestibility and feeding behaviour. Total-mixed rations consisted of maize silage, grass silage and a soyabean meal-based concentrate mixture, each at 250g/kg DM, with the remaining 250g consisting of cracked wheat/soya hulls (SH) in the ratios of 250:0, 167:83; 83:167 and 0:250 g, respectively, for treatments SH0, SH83, SH167 and SH250. Starch concentrations were 302, 248, 193 and 140g/kg DM, and NDF concentrations were 316, 355, 394 and 434g/kg DM, for treatments SHO, SH83, SH167 and SH250, respectively. Total eating time increased (p < 0.05) as SH inclusion increased, but total rumination time was unaffected. Digestibility of DM, organic matter and starch declined (p < 0.01) as SH inclusion increased, whilst digestibility of NDF and ADF increased (p < 0.01). Dry-matter intake tended to decline with increasing SH, whilst bodyweight, milk yield and fat and lactose concentrations were unaffected by treatment. Milk protein concentration decreased (p < 0.01) as SH level increased. Feed conversion efficiency improved (p < 0.05) as SH inclusion rose, but it was not possible to determine whether this was due to the increased fibre levels alone, or the favourable effect on rumen fermentation of decreasing starch levels. (c) 2006 Elsevier B.V. All rights reserved.
Resumo:
Diet digestibility and rate of passage, eating and rumination behavior, dry matter intake (DMI), and lactation performance were compared in 6 Jersey and 6 Holstein multiparous cows. Cows were fed gestation diets according to body weight (BW) beginning 7 wk before expected calving and ad libitum amounts of a lactation diet postpartum. Diet digestibility and rate of passage were measured in 5-d periods at wk 5 prepartum and wk 6 and 14 of lactation. Eating and ruminating behavior was measured over 5-d periods at wk 5 and 2 prepartum and wk 2, 6, 10, and 14 of lactation. Milk yield and DMI were higher in Holsteins, but milk energy output per kilogram of metabolic BW (BW0.75) and intake capacity (DMI/kg of BW) did not differ between breeds. Holsteins spent longer ruminating per day compared with Jerseys, but daily eating time did not differ between breeds. Jerseys spent more time eating and ruminating per unit of ingested feed. The duration and number of meals consumed did not differ between breeds, but the meals consumed by Jerseys were distributed more evenly throughout each 24-h period, providing a more regular supply of feed to the rumen. Feed passed through the digestive tract more quickly in Jerseys compared with Holsteins, suggesting particle breakdown and rumen outflow were faster in Jerseys, but this may also reflect the relative size of their digestive tract. Neutral detergent fiber digestibility was greater in Jerseys, despite the shorter rumen retention time, but digestibility of dry matter, organic matter, starch, and N did not differ between breeds. Utilization of digested N for tissue retention was higher at wk 5 prepartum and lower at wk 14 of lactation in Jerseys. In contrast to numerous published studies, intake capacity of Jerseys was not higher than that of Holsteins, but in the present study, cows were selected on the basis of equal expected milk energy yield per kilogram of metabolic BW. Digestibility of neutral detergent fiber and rate of digesta passage were higher in Jerseys, probably as a consequence of increased mastication per unit of feed consumed in Jerseys and their smaller size.
Resumo:
An experiment was conducted to determine the effects of including cottonseed cake in rations for weaned growing pigs. Thirty-two Landrace x Large White pigs, weighing 20-24 kg, were included in four blocks formed on the basis of initial weight within sex in an otherwise completely randomized block design. The pigs were killed when they reached a live weight of 75.0 +/- 2.0 kg and the half careases were analysed into cuts and the weights of the organs were recorded. An estimate of the productivity of the pigs on each diet was calculated. Cottonseed cake reduced the voluntary feed intake (p < 0.001) and live weight gains (p < 0.001) and increased the heart, kidney and liver weights (p < 0.01). The pigs on the soya bean-based control diet took the shortest time to reach slaughter weight. The result was probably in part due to lysine deficiency and in part to the effect of free gossypol. It was found that it is at present cost-effective to include cottonseed cake in pig weaner grower diets up to 300 g/kg in Cameroon.
Resumo:
Since estimated dietary selenium intake in the UK has declined steadily from around 60 mug day(-1) in 1975 to 34 mug day(-1) in 1997, there is a need to increase selenium intake from staple foods such as milk and milk products. An experiment was therefore done to investigate the relationship between dietary source and concentration of selenium and the selenium content of bovine milk. In a 3 x 3 factorial design, 90 mid-lactation Holstein dairy cows were supplemented over 8 weeks with either sodium selenite (S), a chelated selenium product (Selenium Metasolate(TM)) (C) or a selenium yeast (Sel-plex(TM)) (Y) at three different dietary inclusion levels of 0.38 (L), 0.76 (M) and 1.14 (H) mg kg(-1) dry matter (DM). Significant increases in milk selenium concentration were observed for all three sources with increasing inclusion level in the diet, but Y gave a much greater response (up to +65 mug l(-1)) than the other two sources of selenium (S and C up to +4 and +6 mug l(-1) respectively). The Y source also resulted in a substantially higher apparent efficiency of transfer of selenium from diet to milk than S or C. Feeding Y at the lowest dietary concentration, and thus within the maximum level permitted under EU regulations, resulted in milk with a selenium concentration of 28 mug l(-1). If the selenium concentration of milk in the UK was increased to this value, it would, at current consumption rates, provide an extra 8.7 mug selenium day(-1), or 11 and 14% of daily recommended national intake for men and women respectively. (C) 2004 Society of Chemical Industry.