68 resultados para History of toxinology


Relevância:

100.00% 100.00%

Publicador:

Relevância:

100.00% 100.00%

Publicador:

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A radiocarbon-dated multiproxy palaeoenvironmental record from the Lower Thames Valley at Hornchurch Marshes has provided a reconstruction of the timing and nature of vegetation succession against a background of Holocene climate change, relative sea level movement and human activities. The investigation recorded widespread peat formation between c. 6300 and 3900 cal. yr BP (marine ‘regression’), succeeded by evidence for marine incursion. The multiproxy analyses of these sediments, comprising pollen, Coleoptera, diatoms, and plant and wood macrofossils, have indicated significant changes in both the wetland and dryland environment, including the establishment of Alnus (Alder) carr woodland, and the decline of both Ulmus (Elm; c. 5740 cal. yr BP) and Tilia (Lime; c. 5600 cal. yr BP, and 4160–3710 cal. yr BP). The beetle faunas from the peat also suggest a thermal climate similar to that of the present day. At c. 4900 cal. yr BP, Taxus (L.; Yew) woodland colonised the peatland forming a plant community that has no known modern analogue in the UK. The precise reason, or reasons, for this event remain unclear, although changes in peatland hydrology seem most likely. The growth of Taxus on peatland not only has considerable importance for our knowledge of the vegetation history of southeast England, and NW Europe generally, but also has wider implications for the interpretation of Holocene palaeobotanical records. At c. 3900 cal. yr BP, Taxus declined on the peatland surface during a period of major hydrological change (marine incursion), an event also strongly associated with the decline of dryland woodland taxa, including Tilia and Quercus, and the appearance of anthropogenic indicators.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Aromatic amino acid hydroxylase (AAAH) genes and insulin-like genes form part of an extensive paralogy region shared by human chromosomes 11 and 12, thought to have arisen by tetraploidy in early vertebrate evolution. Cloning of a complementary DNA (cDNA) for an amphioxus (Branchiostoma floridae) hydroxylase gene (AmphiPAH) allowed us to investigate the ancestry of the human chromosome 11/12 paralogy region. Molecular phylogenetic evidence reveals that AmphiPAH is orthologous to vertebrate phenylalanine (PAH) genes; the implication is that all three vertebrate AAAH genes arose early in metazoan evolution, predating vertebrates. In contrast, our phylogenetic analysis of amphioxus and vertebrate insulin-related gene sequences is consistent with duplication of these genes during early chordate ancestry. The conclusion is that two tightly linked gene families on human chromosomes 11 and 12 were not duplicated coincidentally. We rationalize this paradox by invoking gene loss in the AAAH gene family and conclude that paralogous genes shared by paralogous chromosomes need not have identical evolutionary histories.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This essay traces the development of Otto Neurath’s ideas that led to the publication of one of the first series of children’s books produced by the Isotype Institute in the late 1940s, the Visual History of Mankind. Described in its publicity material as ‘new in content’ and ‘new in method’, it embodied much of Otto Neurath’s thinking about visual education, and also coincided with other educational ideas in the UK in the 1930s and 1940s. It exemplified the Isotype Institute’s approach: teamwork, thinking about the needs of younger readers, clear explanation, and accessible content. Further, drawing on correspondence, notes and drawings from the Otto and Marie Neurath Isotype Collection at the University of Reading, the essay presents insights to the making of the books and the people involved, the costs of production and the influence of this on design decisions, and how the books were received by teachers and children.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This is a history of fascist Italy from 1919 to 1945 that explores through the private (and mostly unpublished) diaries, letters and memoirs of ordinary people, how the regime was lived and experienced. It sets out to examine the emotional, cultural and ideological landscape of fascism and to investigate what it was that induced so many millions of people to give their support, in varying degrees, to a regime that led the country ultimately to disaster.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The literature suggests that there is significant familial aggregation of eating disorders. A specific association has also been reported between childhood feeding problems and maternal eating disorder. This study investigates whether subgroups of children with early onset eating disturbance are distinguished by maternal eating disorder history. The mothers of 66 children with either anorexia nervosa (AN), food avoidance emotional disorder (FAED) or selective eating (SE) were interviewed to ascertain eating disorder history. Seventeen per cent of mothers reported a history of eating disorder, compared with 3%–5% reported for community samples. A history of eating disorder was reported by 5.9% of mothers of children with SE, 12.9% of mothers of children with AN and 33.3% of mothers of children with FAED. The findings, based on this small sample, suggest that children with FAED are especially likely to have grown up in a dysfunctional food environment.