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1.
In the program of research into the natural history of coalworkers'' pneumoconiosis now being carried out in Great Britain, emphasis is being put upon the importance of sharpening and validating means for early diagnosis, and upon the need for follow-up studies upon properly selected population samples. Existing information from morbidity and mortality figures from chronic bronchitis and emphysema in Great Britain suggests that atmosphere pollutants are important etiological factors. A parallel is drawn between the course of events in pneumoconiosis, in which dust retention in the lungs does not greatly disable until complicated by tuberculous infection, and a hypothesis that bronchitis is a hypersecretion of bronchial mucus caused by atmospheric irritants and does not disable but encourages secondary infection which may cause emphysema. This hypothesis requires testing by follow-up studies of population samples exposed to various environmental influences. It is suggested that in order to bring this common and disabling disease under control, clinicians must widen their interests beyond the confines of the hospital walls.  相似文献   

2.
The paper is concerned with the results of roentgenofunctional investigation of 293 miners, among them there were 63 patients with dust bronchitis and 230 patients with the main types of dust disease (anthracosis, silicosis and anthracosilicosis). Two-stage roentgenopneumopolygraphy (RPPG) with a chess grid and spiral pneumoroentgenography (SPRG) with a spiral grid were employed. Respiratory dysfunction in patients with pneumoconiosis depended on an x-ray and morphological type of fibrosis and stage of disease rather than on its type. The formation of zones of emphysematous inflation in the apical area, in the upper and middle regions of the lungs was revealed, however signs of basal emphysema were ++undetectable. Analysis of RPPG and SPRG findings has shown that unlike pneumoconiosis, dust bronchitis is characterized by earlier development of respiratory dysfunction of more noticeable type, particularly in early signs of disease.  相似文献   

3.
Dermatoglyphic traits proved to be closely associated with chronic mechanic bronchitis (CMB). With the most informative traits identified, it is possible to estimate the individual predisposition to this occupational disorder and thereby to increase the efficiency of preliminary and follow-up medical examinations. Comparison with data on dermatoglyphic traits predisposed to various types of pneumoconiosis supported the hypothesis on a single mechanical lung disease or "general dust lung disease".  相似文献   

4.
Although epidemic infectious diseases are a recognized cause of changes in host population dynamics, there is little direct evidence for the effect of endemic infections on populations. Cowpox virus is an orthopoxvirus which is endemic in bank voles (Clethrionomys glareolus), wood mice (Apodemus sylvaticus) and field voles (Microtus agrestis) in Great Britain. It does not cause obvious signs of disease nor does it affect survival, but in this study we demonstrate experimentally that it can reduce the fecundity of bank voles and wood mice by increasing the time to first litter by 20-30 days. The pathogenic mechanisms causing this effect are at present not known, but this finding suggests that natural subclinical infection could have a considerable effect on the dynamics of wild populations.  相似文献   

5.
A correlation survey has been carried out between the pathological, physiological, and radiological findings pertaining to emphysema in 247 deceased coal miners and ex-miners, most of whom had been diagnosed as suffering from coal workers'' pneumoconiosis during life. The pathological findings, which included large lung sections and detailed histology in every case, were compared with similar findings in a contrast non-mining population matched for age and sex.The results indicated that emphysema was much more common among the coal miners, both with simple and with complicated pneumoconiosis, than among the contrast group. In addition the extent of the emphysema as measured by a recognized “counting” method carried out on paper-mounted lung sections was remarkably closely related to ventilatory impairment as evidenced by the forced expiratory volume in one second.Extensive emphysema was more commonly found in those pneumoconiosis cases, both simple and complicated, showing the finer punctiform type of radiological change than in cases showing the larger micronodular and nodular opacities.  相似文献   

6.
The Eurasian red squirrel’s (Sciurus vulgaris) history in Ireland is largely unknown, but the original population is thought to have been driven to extinction by humans in the seventeenth century, and multiple records exist for its subsequent reintroduction in the nineteenth century. However, it is currently unknown how these reintroductions affect the red squirrel population today, or may do so in the future. In this study, we report on the development of a DNA toolkit for the non-invasive genetic study of the red squirrel. Non-invasively collected red squirrel samples were combined with other samples collected throughout Ireland and previously published mitochondrial DNA (mtDNA) data from Ireland, Great Britain and Continental Europe to give an insight into population genetics and historical introductions of the red squirrel in Ireland. Our findings demonstrate that the Irish red squirrel population is on a national scale quite genetically diverse, but at a local level contains relatively low levels of genetic diversity, and there is also evidence of genetic structure. This is likely an artefact of the introduction of a small number of genetically similar animals to specific sites. A lack of continuous woodland cover in Ireland has prevented further mixing with animals of different origins that may have been introduced even to neighbouring sites. Consequently, some of these genetically isolated populations are or may in the future be at risk of extinction. The Irish red squirrel population contains mtDNA haplotypes of both a British and Continental European origin, the former of which are now extinct or simply not recorded in contemporary Great Britain. The Irish population is therefore important in terms of red squirrel conservation not only in Ireland, but also for Great Britain, and should be appropriately managed.  相似文献   

7.
  1. The American mink Neovison vison in Great Britain is an invasive alien species, with significant impacts on native prey species. There have been suggestions that populations of mink in Britain have declined since the 1990s.
  2. Three nationwide data sets include data on mink distribution and abundance. Scat surveys and the National Game Bag Census suggest population declines, but the latter does not take account of survey effort (which may also have declined) and the former is misleading because there is evidence that mink change their marking behaviour in the presence of otters Lutra lutra. National Biodiversity Network data suggest an increase in mink numbers, but this can be explained by a concomitant increase in mammal recording.
  3. Although intra-guild competition between invasive mink and native otters is likely, there is no evidence that otters have caused a decline in mink numbers. There is little information on the impact of disease, or exposure to rodenticides, on wild mink – both warrant further attention. Eradication efforts can have an impact on mink populations, but currently neither implementation nor monitoring is sufficient to generate effects throughout Great Britain or to assess the impact of cumulative local and regional efforts.
  4. We conclude that it is not possible, on the basis of currently available data for Great Britain, to ascertain the status of mink or assess the underlying trend in their population. We stress the importance of collaboration, coordination, and record keeping (and sharing) in future, proper interpretation of existing data, and the use of alternative data sources. We call for greater, and better, effort in both mink management and monitoring of management in Great Britain.
  相似文献   

8.
Howard A.  Ross 《Journal of Zoology》1983,201(3):351-362
Several hundred starlings (Sturnus vulgaris) were introduced to New Zealand from Great Britain during1860–1880. Allozymic variation at 24 loci was analysed in winter populations sampled at six localities in each country. New Zealand samples had fewer alleles per locus but the same mean heterozygosity (3% per locus) and proportion of polymorphic loci as did British samples. Winter populations in Britain contain European migrants and were genetically homogeneous. Paradoxically, genetic distances among derived New Zealand populations, and between New Zealand and Great Britain were much greater, similar in magnitude to those observed among allopatric populations in other avian species. The geographical pattern of genetic variation in New Zealand suggests that reproductive isolation of populations and random drift have contributed to the development of population differentiation.  相似文献   

9.
Biological invasions are not only events with substantial environmental and socioeconomic impacts but are also interesting natural experiments, allowing the study of phenomena such as the cultural evolution of bird song following introduction. We took an excellent opportunity to compare the distribution of dialects of the yellowhammer Emberiza citrinella, a small Eurasian passerine, in its native source region (Great Britain) and invaded range (New Zealand) more than hundred years after relocation. Recent field recordings (including those provided by volunteers within a citizen science project) were complemented by those from archives, each assigned to appropriate dialect by visual inspection of a sonogram, and the resulting spatial patterns of dialect distribution were interpreted using historical data on the yellowhammer invasion. The two countries differ markedly in the composition and distribution of dialects. New Zealand populations sing a greater number of different dialects, seven in total, five of which were not detected in the current British population, but have been reported by previous studies from the continental Europe. Two identified localities of capture (Brighton, Sussex, UK) and release (Dunedin, Otago, NZ) differ even more strikingly, having no dialects in common. The largely sedentary nature of yellowhammers allows for two mutually exclusive explanations for European dialects being detected in New Zealand but not in Great Britain: 1) the corresponding song types have emerged de novo in New Zealand, through convergent cultural evolution; 2) the dialects have disappeared from Great Britain, while being preserved in New Zealand. Indirect evidence from the widespread occurrence of these dialects in continental Europe and the reported stability of yellowhammer song, supports the latter explanation. We suggest that the yellowhammer dialect system is an avian equivalent of a phenomenon already noted in human languages, in which ancient words or structures are retained in expatriate communities.  相似文献   

10.
The high mortality from chronic bronchitis in England and Wales and the excess of urban over rural mortality are unexplained. On dividing England and Wales into 212 local authority areas a strong geographical relation was found between death rates from chronic bronchitis and emphysema in 1959-78 and infant mortality from bronchitis and pneumonia during 1921-5. It was concluded that this relation provided strong evidence of a direct casual link between acute lower respiratory infection in early childhood and chronic bronchitis in adult life. Regression analysis suggested that infection in early childhood had a greater influence than cigarette smoking in determining the geographical distribution of chronic bronchitis. National time trends reflected the influence of both factors. Chronic air pollution in adult life may be less important a cause of chronic bronchitis than previously supposed.  相似文献   

11.
We assessed whether nest size affects the probability of nest loss using dyads of large and small (large being twice the size of small) inactive Great Reed Warbler Acrocephalus arundinaceus nests placed at similar sites in Great Reed Warbler territories. Large nests were not predated significantly more frequently than small nests. Experimentally enlarged active Great Reed Warbler nests suffered non‐significantly higher predation compared with non‐manipulated control nests. Our experiments did not support the nest‐size hypothesis and suggested that nest size does not appear to be a factor affecting the risk of nest predation in this species. The probability of brood parasitism by the Common Cuckoo Cuculus canorus was also unaffected by experimental nest enlargement, supporting the commonly accepted hypothesis that the Common Cuckoo searches for suitable host nests by host activity during nest building rather than nest size.  相似文献   

12.
In this article we describe an optimization model, a mixed integer program, to determine the optimal locations and capacity sizes of biomass‐based facilities in energy crop supply chains, and demonstrate its use using data for Great Britain. We show the utility of the model for planning the optimal locations of biomass‐based facilities by investigating the supply of feedstock from Miscanthus for Combined Heat and Power (CHP) in Great Britain, based on data of current electricity demand. Results show that CHP cost directly influences its optimal location, and the price of bioelectricity from Miscanthus. At the coarse spatial resolution of the available energy demand data, the sale price of Miscanthus does not greatly influence the quantity of Miscanthus sold in Great Britain. Only when the hypothetical sale price of Miscanthus was closer to CHP cost, was the quantity of Miscanthus sold influenced by the variation in the sale price of Miscanthus. In future, we will apply the model using electricity and heat demand data at fine spatial scale currently being located, which will allow the implications of local production of Miscanthus for CHP to be explored.  相似文献   

13.
An accurate estimate of the prevalence of scrapie infection in the Great Britain (GB) sheep flock is essential when assessing any potential risk to human health through exposure to sheep transmissible spongiform encephalopathies (TSEs). One method for assessing the prevalence is to sample sheep intended for human consumption using a diagnostic test capable of detecting infected animals prior to the onset of clinical signs. An abattoir survey conducted in Great Britain in 1997-1998 tested brain samples from 2809 apparently healthy sheep of which none was found to be positive for scrapie by histopathology or immunohistochemistry (IHC) although 10 were positive for scrapie-associated fibrils (SAF). Subsequently, the tonsils from a subset of the animals sampled were examined using IHC, one of which tested positive. To interpret these results we use a likelihood-based approach, which accounts for the variation in the prevalence of infection with age and test sensitivity and specificity with stage of infection. Combining the results for all of the diagnostic tests yields an estimate of the prevalence of scrapie infection in the GB sheep flock of 0.22% (95% confidence interval: 0.01-0.97%). Moreover, our analysis suggests that all of the diagnostic tests used are very specific (greater than 99%). Indeed, only SAF detection yields a specificity estimate of less than 100%, which helps to account for the high number of samples found to be positive for SAF.  相似文献   

14.
Understanding the factors that influence plant distributions is a considerable challenge for ecologists in the face of environmental change. Here, we quantify spatial and temporal variation in the finite rate of population increase of the annual grass Vulpia fasciculata. Specifically, we test the hypothesis that the northern range boundary is associated with finite rates of population increase of less than one. Seeds of three ecotypes of the annual grass V. fasciculata were introduced annually across a range of sites in Great Britain both within (11) and to the north (4) of its current range boundary in each of 4 years. Populations failed to establish at 17% of target sites due to disturbance. At the remaining target sites, the finite rate of population increase, λ, varied from 0.06 to 33.3 with a geometric mean of 1.88. Of the total variance in the rate of population growth, site and year effects accounted independently for 40% of the variation and in interaction for 50%; ecotype accounted for less than 5% of the variation. Variation in the weather between sites and years had little impact on plant performance, and there was no indication that the rate of population growth was lower to the north of the current range boundary. We conclude that current climatic conditions on the coast of Great Britain are not limiting the distribution of V. fasciculata and that seeds from across its current range have roughly equivalent colonising potential.  相似文献   

15.
The publication of the Statistics of Scientific Procedures on Living Animals: Great Britain 2005 once again provides evidence that the levels of animal experimentation in Great Britain are rising, the underlying reason for this being the continued and increasing reliance on genetically modified animals as model systems. There has been a gradual increase in fundamental research, as applied toxicological studies have declined. Of particular concern is the impact that the forthcoming REACH legislation will have and the apparent lack of urgency in facing up to this challenge. The major issues arising from the Statistics are discussed, including the increases in rabbit and primate procedures. The potential of newly validated and emerging techniques to counteract these worrying trends are also considered.  相似文献   

16.
Cigarette smoke-induced animal models of chronic obstructive pulmonary disease support the protease-antiprotease hypothesis of emphysema, although which cells and proteases are the crucial actors remains controversial. Inhibition of either serine or metalloproteases produces significant protection against emphysema, but inhibition is invariably accompanied by decreases in the inflammatory response to cigarette smoke, suggesting that these inhibitors do more than just prevent matrix degradation. Direct anti-inflammatory interventions are also effective against the development of emphysema, as are antioxidant strategies; the latter again decrease smoke-induced inflammation. There is increasing evidence for autoimmunity, perhaps directed against matrix components, as a driving force in emphysema. There is intriguing but controversial animal model evidence that failure to repair/failure of lung maintenance also plays a role in the pathogenesis of emphysema. Cigarette smoke produces small airway remodeling in laboratory animals, possibly by direct induction of fibrogenic growth factors in the airway wall, and also produces pulmonary hypertension, at least in part through direct upregulation of vasoactive mediators in the intrapulmonary arteries. Smoke exposure causes goblet cell metaplasia and excess mucus production in the small airways and proximal trachea, but these changes are not good models of either chronic bronchitis or acute exacerbations. Emphysema, small airway remodeling, pulmonary hypertension, and mucus production appear to be at least partially independent processes that may require different therapeutic approaches.  相似文献   

17.
Bovine tuberculosis (BTB) is a multi-species infection that commonly affects cattle and badgers in Great Britain. Despite years of study, the impact of badgers on BTB incidence in cattle is poorly understood. Using a two-host transmission model of BTB in cattle and badgers, we find that published data and parameter estimates are most consistent with a system at the threshold of control. The most consistent explanation for data obtained from cattle and badger populations includes within-host reproduction numbers close to 1 and between-host reproduction numbers of approximately 0.05. In terms of controlling infection in cattle, reducing cattle-to-cattle transmission is essential. In some regions, even large reductions in badger prevalence can have a modest impact on cattle infection and a multi-stranded approach is necessary that also targets badger-to-cattle transmission directly. The new perspective highlighted by this two-host approach provides insight into the control of BTB in Great Britain.  相似文献   

18.
Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is native to Asia, and was widely introduced as a biocontrol agent of aphids and coccids in Europe and North America. In Europe H. axyridis is considered to be an invasive alien species. Although not known to have been deliberately introduced to Great Britain, it was first recorded there in 2004, in south-east England. Harmonia axyridis arrived in Great Britain by various means, primarily from mainland Europe, but also from Canada. Extensive national and local media coverage, and a dedicated website (), facilitated public involvement in recording H. axyridis in Great Britain; in excess of 4,000 verified records of the species were received between 2004 and 2006. Through detailed mapping, the objective of our study was to quantify and analyse the spread of H. axyridis in its early stages of invasion in Great Britain. Our data shows that between 2004 and 2006, the species spread north through Great Britain at the rate of 58 km year-1 and west at the rate of 144.5 km year-1. In England H. axyridis spread north to Yorkshire and west to Cornwall by the end of 2006, and also reached Wales. Recorded occurrence (of one or more H. axyridis individuals at larval, pupal and/or adult stage) in 10 km squares in Great Britain was: 2004—51; 2005—149; 2006—447. Records of juvenile H. axyridis extend through most of the recorded British range of the species, and we present evidence of bi-voltinism in the population in 2006.  相似文献   

19.
Results from a correlation survey which compared radiological and physiological findings during life with detailed morbid anatomical findings in the lungs of 247 deceased miners and ex-miners with pneumoconiosis were used to assess the extent and significance of their pulmonary disability.Coal workers'' pneumoconiosis usually caused progressive impairment of ventilation, which in the simple type of disease was not related to radiological category. In such cases the presence of emphysema was found to be a more important factor in determining the impairment of ventilation than the radiological category of simple pneumoconiosis.  相似文献   

20.
The greater part of the literature on European fishes reports the widespread occurrence of an introduced North American catfish and identifies it as Ictalurus nebulosus. Study of the literature reporting critical determinations and of specimens from Europe and Great Britain reveals the presence of two species, I nebulosus and I melas. These fishes are widely used in experimental studies, usually being obtained through aquarium-fish dealers indirectly from continental Europe. Mostly they are incorrectly identified as I nebulosus. There is reason to believe that I melas is the more commonly imported catfish in Britain; both species occur feral in mainland Europe.  相似文献   

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