324 resultados para British Isles
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This paper presents the results of recent palaeoentomological research carried out in the Humberhead Levels, South Yorkshire, UK, including the discovery of fossils of five species of beetle previously unknown in the British Isles. The significance of these and other Urwaldrelikt species is discussed in relation to the fragmentation of forest habitats, particularly those associated with Pinus sylvestris L. The Holocene history of this tree and its associated taxa is examined. The importance of fire habitats and the dependence of some pinicolous taxa on these habitats suggests that the decline of fire ecosystems may have had some impact on the changing biogeography of some species.
Chironomid-inferred Late-Glacial Summer Air Temperatures From Lough Nadourcan, Co. Donegal, Ireland.
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Western Ireland, located adjacent to the North Atlantic, and with a strongly oceanic climate, is potentially sensitive to rapid and extreme climate change. We present the first high-resolution chironomid-inferred mean July temperature reconstruction for Ireland, spanning the late-glacial and early Holocene (LGIT, 15-10 ka BP). The reconstruction suggests an initial rapid warming followed by a short cool phase early in the interstadial. During the interstadial there are oscillations in the inferred temperatures which may relate to Greenland Interstadial events GI-1a-e. The temperature decrease into the stadial occurs in two stages. This two-stage drop can also be seen in other late-glacial chironomid-inferred temperature records from the British Isles. A stepped rise in temperatures into the Holocene, consistent with present-day temperatures in Donegal, is inferred. The results show strong similarities with previously published LGIT chironomid-inferred temperature reconstructions, and with the NGRIP oxygen-isotope curve, which indicates that the oscillations observed in the NGRIP record are of hemispherical significance. The results also highlight the influence of the North Atlantic on the Irish climate throughout the LGIT.
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Carbon stable-isotope analysis showed that individual brown trout Salmo trutta in Loch Lomond adopted strategies intermediate to that of freshwater residency or anadromy, suggesting either repeated movement between freshwater and marine environments, or estuarine residency. Carbon stable-isotope (delta C-13) values from Loch Lomond brown trout muscle tissue ranged from those indicative of assimilation of purely freshwater-derived carbon to those reflecting significant utilization of marine-derived carbon. A single isotope, two-source mixing model indicated that, on average, marine C made a 33% contribution to the muscle tissue C of Loch Lomond brown trout. Nitrogen stable isotope, delta N-15, but not delta C-13 was correlated with fork length suggesting that larger fish were feeding at a higher trophic level but that marine feeding was not indicated by larger body size. These results are discussed with reference to migration patterns in other species. (c) 2008 The Authors Journal compilation (c) 2008 The Fisheries Society of the British Isles.
Testing the stability of the benefit transfer function for discrete choice contingent valuation data
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This paper examines the stability of the benefit transfer function across 42 recreational forests in the British Isles. A working definition of reliable function transfer is Put forward, and a suitable statistical test is provided. A novel split sample method is used to test the sensitivity of the models' log-likelihood values to the removal of contingent valuation (CV) responses collected at individual forest sites, We find that a stable function improves Our measure of transfer reliability, but not by much. We conclude that, in empirical Studies on transferability, considerations of function stability are secondary to the availability and quality of site attribute data. Modellers' can study the advantages of transfer function stability vis-a-vis the value of additional information on recreation site attributes. (c) 2008 Elsevier GmbH. All rights reserved.
Resumo:
Eusociality is widely considered a major evolutionary transition. The socially polymorphic sweat bee Halictus rubicundus, solitary in cooler regions of its holarctic range and eusocial in warmer parts, is an excellent model organism to address this transition, and specifically the question of whether sociality is associated with a strong barrier to gene flow between phenotypically divergent populations. Mitochondrial DNA (COI) from specimens collected across the British Isles, where both solitary and social phenotypes are represented, displayed limited variation, but placed all specimens in the same European lineage; haplotype network analysis failed to differentiate solitary and social lineages. Microsatellite genetic variability was high and enabled us to quantify genetic differentiation among populations and social phenotypes across Great Britain and Ireland. Results from conceptually different analyses consistently showed greater genetic differentiation between geographically distant populations, independently of their social phenotype, suggesting that the two social forms are not reproductively isolated. A landscape genetic approach revealed significant isolation by distance (Mantel test r = 0.622, p
Resumo:
Diabetic nephropathy (DN) is the primary cause of morbidity and mortality in patients with type 1 diabetes mellitus (T1DM) and affects about 30% of these patients. We have previously localized a DN locus on chromosome 3q with suggestive linkage in Finnish individuals. Linkage to this region has also been reported earlier by several other groups. To fine map this locus, we conducted a multistage case-control association study in T1DM patients, comprising 1822 cases with nephropathy and 1874 T1DM patients free of nephropathy, from Finland, Iceland, and the British Isles. At the screening stage, we genotyped 3072 tag SNPs, spanning a 28 Mb region, in 234 patients and 215 controls from Finland. SNPs that met the significance threshold of p
Resumo:
This study investigates how habitat variation affects sett density, the number of animals per social group and group territory size in the badger (Meles meles). Identical methods were applied in three habitat types: lowland parkland with mixed woodland, pastoral farmland and upland rough pasture with moorland, representing areas of presumed good, medium and poor badger habitat, respectively. Contiguous main setts were identified and bait-marking was used to estimate territory size. Group size was estimated by direct enumeration. Variation in sett density, group size and territory size supported the hypothesis that badger group and territory size are influenced by habitat type. This was further supported by analyses of data from other studies in the British Isles. The implications for badger spatial ecology, badger survey techniques and the badger's role in the epidemiology of TB are discussed.
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Human cases of Q fever appear to be common in Northern Ireland compared to the rest of the British Isles. The purpose of this study was to describe the seroepidemiology of Coxiella burnetii infection in cattle in Northern Ireland in terms of seroprevalence and determinants of infection. A total of 5182 animals (from a stratified systematic random sample of 273 herds) were tested with a commercial C. burnetii phase 2 IgG ELISA. A total of 6.2% of animals and 48.4% of herds tested positively. Results from a multilevel logistic regression model indicated that the odds of cattle being infected with Q fever increased with age, Friesian breed, being from large herds and from dairy herds. Large dairy herd animal prevalence was 12.5% compared to 2.1% for small beef herds. Preliminary seroprevalence in sheep (12.3%), goats (9.3%), pigs (0%) rats (9.7%) and mice (3.2%) using indirect immunofluorescence is reported.
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Two species of Osmundea Stackhouse (Rhodomelaceae, Rhodophyta) that occur in Atlantic Europe have been confused under the names Osmundea ramosissima (Oeder) Athanasiadis and Osmundea truncata (Kutzing) Nam et Maggs, regarded until now as a synonym of O. ramosissima, An epitype from its type locality (Stavanger, Norway) is selected for Osmundea ramosissima Athanasiadis, recognized here as a valid name for Fucus ramosissimus Oeder, nom. illeg. Details of vegetative and reproductive morphology of O. ramosissima are reported, based on material from France, the British Isles, and Helgoland. Osmundea ramosissima resembles other species of Osmundea in its vegetative axial segments with two pericentral cells and one trichoblast, spermatangial development from apical and epidermal cells (filament type), the formation of five pericentral cells in the procarp-bearing segment of the female trichoblast, and tetrasporangial production from random epidermal cells. Among the species of Osmundea, O. ramosissima is most similar to O. truncata. Both species have discoid holdfasts, secondary pit connections between epidermal cells, and cup-shaped spermatangial pits. They differ in that: (a) O. ramosissima lacks lenticular wail thickenings and refractive needle-like inclusions in medullary cells, both of which are present in O. truncata; (b) O. ramosissima has branched spermatangial filaments that terminate in a cluster of several cells, whereas in O. truncata the unbranched spermatangial filaments have a single large terminal sterile cell; and (c) cystocarps of O. ramosissima lack protuberant ostioles but ostioles are remarkably protuberant in o. truncata. Phylogenetic analyses of rbcL sequences of Laurencia obtusa (Hudson) Lamouroux and all five Atlantic European species of Osmundea, including the type species, strongly support the generic status of Osmundea. Osmundea ramosissima and O. truncata are closely related (5.2% sequence divergence) and form a well-supported clade sister to a clade consisting of O. pinnatifida (Hudson) Stack-house, O. osmunda Stackhouse and O. hybrida (A. P. de Candolle) Nam. The formation of secondary pit connections between epidermal cells is a synapomorphy for the O. ramosissima + O. truncata clade. The close relationship between species with cup-shaped spermatangial pits (Osmundea hybrida) and urn-shaped pits (Osmundea pinnatifida and Osmundea osmunda) shows that spermatangial pit shape is not an important phylogenetic character. Parsimony analysis of a morphological data set also supports the genus Osmundea but conflicts with the molecular trees in infrageneric relationships, placing O. hybrida basal within the Osmundea clade and grouping O. osmunda and O. pinnatifida but not O. truncata and O. ramosissima. A key to Osmundea species is presented.
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The genus Polysiphonia Greville, nom. cons., has had a long and confused nomenclatural history. At present, Polysiphonia has a wide circumscription, including at least 200 species, but it is heterogeneous in many vegetative and reproductive developmental features. Central to any re-evaluation of the genus is a detailed examination of the type species of Polysiphonia, P. urceolata (Lightfoot ex Dillwyn) Greville, which is conspecific with P. stricta (Dillwyn) Greville. We here report on the vegetative and reproductive morphology of P. stricta, including P, urceolata, based on type and other material from the British Isles. Thalli consist of prostrate and erect ecorticate axes with four pericentral cells, attached by unicellular rhizoids remaining in open connection with pericentral cells. Prostrate axes lack vegetative trichoblasts; trichoblasts occur seasonally on erect axes. Branch initials are cut off from the subapical cell at intervals of four or five segments in dichotomous and alternating pairs rather than being formed horn each axial cell in the spiral pattern typical of most species of Polysiphonia. Spermatangial branch initials, which are trichoblast homologues, are produced directly from each axial cell at the tips of erect branches, not subtended by trichoblasts, and have two- to five-celled sterile tips when mature. The mature carpogonial branch is four-celled with a two-celled first sterile group and a one-celled second sterile group. Following presumed fertilization, direct fusion apparently takes place between carpogonium and auxiliary tell; mature cystocarps are usually urceolate. Tetrasporangia are formed from the third pericentral cell, in straight series, and have two pre-sporangial cover cells. Previous accounts of a third, post-sporangial cover cell could not be substantiated. P. stricta and a small group of other Polysiphonia species differ in several important respects from most members of the genus, which have rhizoids cut off from pericentral cells by a cell division, abundant trichoblasts, spirally arranged tetrasporangia and a post-sporangial cover cell. The branching pattern of P. stricta highlights the difficulties of distinguishing between the tribes Polysiphonieae and Pterosiphonieae.
Resumo:
Four of the five members of the Dasyaceae found in the British Isles, Dasya corymbifera J. Agardh, Dasya hutchinsiae Harvey, Dasya punicea Meneghini ex Zanardini and Heterosiphonia plumosa (Ellis) Batters, appear to have Polysiphonia-type life histories on the basis of evidence from field collections of tetrasporophytes and gametophytes. In collections from the British Isles of the fifth species, Dasya ocellata (Grateloup) Harvey, only tetrasporophytes have ever been observed, but there are two reports of gametophytes in this species from further south in Europe. Dasya ocellata tetraspores were isolated into culture from populations in Strangford Lough, Northern Ireland, and Agadir, Morocco, where one female thallus was collected amongst tetrasporophytes. Dasya ocellata from Ireland underwent a direct tetraspore-to-tetrasporophyte life history, which was followed through two complete cycles. Karyological studies showed that meiosis does not occur during tetrasporangial development: tetrasporangia are mitotic, with c. 64 small chromosomes. Comparison with chromosome numbers in meiotic tetrasporangia of D. hutchinsiae (n = c. 32) showed that this is the diploid chromosome complement. Tetraspores from the Moroccan isolate, by contrast, gave rise to gametophytes (although only the males became fertile) and tetrasporophyte recycling did not occur. Thalli sampled from a population in southern Portugal consisted only of tetrasporophytes. Dasya ocellata, like many members of the Ceramiales, shows intraspecific life history variability; a sexual life history apparently occurs only in southern populations.
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"Managing Island Life: Social, Economic and Political Dimensions of Formality and Informality in Island Life" is a significant and timely contribution to the study of islands and island life. Wide-ranging in terms of both geographical and theoretical sweep, contributions consider the conceptualisation of the island as well as social, economic and political dimensions of island life and living. Showcasing the current state of island research, contributors cover diverse areas of island life such as: informal economies in the West Indies; the effects of natural convservation policies in the Highlands and Islands of Scotland; the role of internet sites in British Isles heritage tourism, and the impact of multicultural policies in the Indian Ocean. This volume will appeal to undergraduate social scientists as well as professional anthropologists, sociologists and geographers, policy makers and islands and regional specialists.