64 resultados para Geological Society of London. Library
Resumo:
Weathering rinds have been used for decades as relative age indicators to differentiate glacial deposits in long Quaternary sequences, but only recently has it been shown that rinds contain long and extensive palaeoenvironmental records that often extend far beyond mere repositories of chemical weathering on both Earth and Mars. When compared with associated palaeosols in deposits of the same age, rinds often carry a zonal weathering record that can be correlated with palaeosol horizon characteristics, with respect to both abiotic and biotic parameters. As demonstrated with examples from the French and Italian Alps, rinds in coarse clastic sediment contain weathering zones that correlate closely with horizon development in associated palaeosols of presumed Late Glacial age. In addition to weathering histories in both rinds and palaeosols, considerable evidence exists to indicate that the black mat impact (12.8 ka) reached the European Alps, a connection with the Younger Dryas readvance supported by both mineral and chemical composition. Preliminary metagenomic microbial analysis using density gradient gel electrophoresis suggests that the eubacterial microbial population found in at least one Ah palaeosol horizon associated with a rind impact site is different from that in other Late Glacial and Younger Dryas surface palaeosol horizons. © 2013 The Geological Society of London.
Resumo:
Amendments to secularization theory have brought the issue of public religions to the fore in recent years. In particular, the work of Casanova and Beyer has maintained the importance of functional differentiation whilst pointing to the flow of religious discourses across social boundaries. These issues, however, have received little ethnographic attention, such that many of the problems associated with theories of differentiation and globalization have not been engaged in a sustained manner. Research within black majority London Methodist congregations is drawn upon to suggest ways in which these theories can be reconsidered. Three related issues are focused upon: the continued importance of the nation-state (including national stratifications); the importance of a practical approach to religion, such that discourses are understood as ‘practical discourses’; and the importance of not privileging religion by reifying it in functional terms. These considerations have ramifications not only for secularization theory, but the general field of the sociological study of religion.
Resumo:
In Harley 2782, Servius’s late antique commentary on Vergil was transmitted as an independent text, edited, corrected, glossed, marked for mythological information, provided with NOTA monograms and headings, as well as interspersed and augmented with scholia adespota and non-Servian material. The scholarly conventions attested in this manuscript show the kinds of critical apparatus that fed into the early medieval appropriation of Vergil and above all demonstrate that Servius was a staple of the Carolingian world.
Dans le manuscrit Harley 2782, le commentaire tardo-antique de Servius sur Virgile a été transmis sous forme d’un document indépendant, modifié, corrigé, glosé, préparé pour retrouver les informations mythologiques, enrichi de monogrammes Nota, ainsi qu’il a été entrecoupé et augmenté à l’aide des scholia adespota et du matériel non Servien. Les conventions scolastiques attestées par ce manuscrit montrent quels types d’apparats critiques alimentaient le début de l’appropriation médiévale de Virgile et surtout prouvent que Servius était une composante essentielle du monde carolingien.
Resumo:
Peat bogs represent unique ecosystems that are under particular threat from fragmentation due to peat harvesting, with only 38% of the original peatland in Europe remaining intact and unaffected by peat cutting, drainage and silviculture. In this study, we have used microsatellite markers to determine levels and patterns of genetic diversity in both cut and uncut natural populations of the peat moss Polytrichum commune. Overall diversity levels suggest that there is more genetic variation present than had previously been assumed for bryophytes. Despite this, diversity values from completely cut bogs were found to be lower than those from uncut peatlands (average 0.729 versus 0.880). In addition, the genetic diversity was more highly structured in the cut populations, further suggesting that genetic drift is already affecting genetic diversity in peat bogs subjected to fragmentation.
Resumo:
The high level of escapes from Atlantic salmon farms, up to two million fishes per year in the North Atlantic, has raised concern about the potential impact on wild populations. We report on a twogeneration experiment examining the estimated lifetime successes, relative to wild natives, of farm, F1 and F2 hybrids and BC1 backcrosses to wild and farm salmon. Offspring of farm and hybrids (i.e. all F1 , F2 and BC1 groups) showed reduced survival compared with wild salmon but grew faster as juveniles and displaced wild parr, which as a group were significantly smaller. Where suitable habitat for these emigrant parr is absent, this competition would result in reduced wild smolt production. In the experimental conditions, where emigrants survived downstream, the relative estimated lifetime success ranged from 2% (farm) to 89% (BC1 wild) of that of wild salmon, indicating additive genetic variation for survival . Wild salmon primarily returned to fresh water after one sea winter (1SW) but farm and hybrids produced proportionately more 2SW salmon. However, lower overall survival means that this would result in reduced recruitment despite increased 2SW fecundity. We thus demonstrate that interaction of farm with wild salmon results in lowered fitness, with repeated escapes causing cumulative fitness depression and potentially an extinction vortex in vulnerable populations.
Resumo:
A battery of allelic markers at highly polymorphic microsatellite loci was developed and employed to confirm genetically the clonal nature of sibships in nine-banded armadillos. This phenomenon of consistent polyembryony, otherwise nearly unknown among the vertebrates, then was capitalized upon to describe the micro-spatial distributions of numerous clonal sibships in a natural population of armadillos. Adult clonemates were significantly more dispersed than were juvenile sibs, suggesting limited opportunities for altruistic behavioral interactions among mature individuals. These results, and considerations of armadillo natural history, suggest that evolutionary explanations for polyembryony in this species may not reside in the kinds of ecological and kin selection theories relevant to some of the polyembryonic invertebrates. Rather, polyembryony in armadillos may be associated evolutionarily with other reproductive peculiarities of the species, including delayed uterine implantation of a single egg.