185 research outputs found

    Pneumoconiosis in the South Wales anthracite coalfield

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    1. Some other factor co-exists with the silica dust in the production of pneumoconiosis in the Anthracite Coalfield, which the writer prefers to call "the infective factor". 2. Pneumoconiosis is a progressive disease, taking many years, according to the intensity of the exposure, to produce the fibrosis characteristic of the condition. 3. The incidence of the condition increases with the carbon content of the coal. This is most marked in three peak areas of the Anthracite Coalfield, namely, at (1) Ystalyfera, (2) Gwauncaegurwen and (3 ) Ammanford. 4. The Collieries in these areas are warm, dry, and dusty. 5. All classes of underground workmen are liable to develop pneumoconiosis, and this is so whether or not they are actually engaged in boring or handling the rocks. 6. The Registrar General's statistics of the death rate in industrial areas are built solely upon the death certificates issued by the doctor. Such statistics when they refer to the term 'Bronchitis' are often erroneous and misleading in that they do not disclose a true statement as to the cause of death. 7. The first complaint of 80% of the miners suffer in g from pneumononiosis is 'shortness of breath'. 8. It is remarkable how patients can still do an arduous day's work with extensive fibrosis of both lungs. 9.Difficulty is often experienced in finding tubercle bacilli in the sputum, or any evidence of tuberculosis on post mortem examination, even when the clinical features and physical signs are those of fibrosis with tuberculosis. 10. A miner suffering from pneumoconiosis with superadded tuberculosis seems very resistant to the disease. He may linger on for years. But the children of the infected person, if they develop tuberculosis, contract it in a very acute form. 11. Unfortunately, the physical signs in pneumoconiosis are few and rather vague. The characteristic sign on which the writer relies is the prolonged expiration with the almost pathognomonic harshness which one hears at the end of the inspiratory phase. 12. A properly conducted X -Ray examination is, as yet, the most satisfactory and the most accurate means of studying the effect of the inhalation of dust. 13. During the pre-silicotic stage the workman is able to carry out his full days work without complaint. 14. During the first stage silicosis the miner is only able to do light work in the open air. 15. In the 2nd, 3rd, and the stage of silicosis with super-added tuberculosis, the workman is totally incapacitated from following any occupation. 16. There is urgent need for investigation into the preventive measures to be taken to counteract this scourge of the anthracite miners. The prophylactic measures now taken are totally inadequate and only provide for one class of workman. 17. Periodic clinical and X -Ray examinations should be carried out at the Collieries. These should include an examination prior to employment and then at annual intervals. The disease could be detected at an early stage and the workman immediately withdrawn from his underground employment on the first appearance of the signs. 18. The existing compensation procedure is too complicated and too bound up in 'red -tape'. There should be no intervening step between the man's own doctor and the Medical Board. The Regional Medical Officer's examination and certificate could easily be obviated. 19. The present Board with its headquarters at Bristol serves the South West of England and all Wales. This is too large and scattered an area.. A separate Medical Board should be set up at Swansea as the most suitable centre to serve the Anthracite area. 20. Legislation should be introduced to modify the present Silicosis-Asbestosis Compensation Act so that it might include all classes of underground workmen. 21. (a) The number of patients examined and skiagrams taken of their chests: 30. (b) The average age of patients examined: 49.9 years (c) The number of patients with sputa. positive to the tubercle bacillus: 3 = 10% (d) The number of children of patients. examined who have died from pulmonary tuberculosis: 3 = 10% (e) The number of children of patients examined who are at present suffering from pulmonary tuberculosis: 5 = 16.66% (f) The number of patients with a negative sputum but with skiagrams suggestive of super-added Tuberculosis: 17 = 56..66

    Absorption Spectral Slopes and Slope Ratios as Indicators of Molecular Weight, Source, and Photobleaching of Chromophoric Dissolved Organic Matter

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    A new approach for parameterizing dissolved organic matter ( DOM) ultraviolet-visible absorption spectra is presented. Two distinct spectral slope regions ( 275-295 nm and 350-400 nm) within log-transformed absorption spectra were used to compare DOM from contrasting water types, ranging from wetlands (Great Dismal Swamp and Suwannee River) to photobleached oceanic water ( Atlantic Ocean). On the basis of DOM size-fractionation studies ( ultrafiltration and gel filtration chromatography), the slope of the 275-295- nm region and the ratio of these slopes (SR; 275-295- nm slope : 350-400- nm slope) were related to DOM molecular weight ( MW) and to photochemically induced shifts in MW. Dark aerobic microbial alteration of chromophoric DOM ( CDOM) resulted in spectral slope changes opposite of those caused by photochemistry. Along an axial transect in the Delaware Estuary, large variations in SR were measured, probably due to mixing, photodegradation, and microbial alteration of CDOM as terrestrially derived DOM transited through the estuary. Further, SR varied by over a factor of 13 between DOM-rich wetland waters and Sargasso Sea surface waters. Currently, there is no consensus on a wavelength range for log-transformed absorption spectra. We propose that the 275-295- nm slope be routinely reported in future DOM studies, as it can be measured with high precision, it facilitates comparison among dissimilar water types including CDOM-rich wetland and CDOM-poor marine waters, and it appears to be a good proxy for DOM MW. © 2008, by the American Society of Limnology and Oceanography, Inc

    Spectroscopic Characterization of Oceanic Dissolved Organic Matter Isolated By Reverse Osmosis Coupled With Electrodialysis

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    Oceanic dissolved organic matter (DOM) is one of the largest pools of reduced carbon on Earth, yet DOM remains poorly chemically characterized. Studies to determine the chemical nature of oceanic DOM have been impeded by the lack of efficient and non-fractioning methods to recover oceanic DOM. Here, a DOM fraction (~40 to 86% recovery) was isolated using reverse osmosis/electrodialysis (RO/ED) and analyzed by solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Samples were obtained from biogeochemically distinct environments: photobleached surface gyre, productive coastal upwelling zone, oxygen minimum, North Atlantic Deep Water, and North Pacific Deep Water. A ubiquitous ‘background’ refractory carbon pool was apparent throughout the ocean and dominated in the deep Pacific Ocean. Advanced NMR spectral editing revealed that condensed aromatic and quaternary anomeric carbons contribute to this deep refractory DOC pool, the quaternary anomeric carbons being a newly identified and potentially important component of bio-refractory carbohydrate-like carbon. Additionally, our results support the multi-pool (e.g. 3-pool: labile, semi-labile, and refractory) conceptual model of marine DOM biogeochemistry. Surface samples, hypothesized to be enriched in labile and semi-labile DOM, were enriched in carbohydrate-like material consistent with prior studies. High carboxyl signals in the deep Pacific support the hypothesis that a major fraction of the refractory pool consists of carboxyl-rich alicyclic molecules (CRAM)

    Environmental drivers of Culicoides phenology: how important is species-specific variation when determining disease policy?

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    Since 2006, arboviruses transmitted by Culicoides biting midges (Diptera: Ceratopogonidae) have caused significant disruption to ruminant production in northern Europe. The most serious incursions involved strains of bluetongue virus (BTV), which cause bluetongue (BT) disease. To control spread of BTV, movement of susceptible livestock is restricted with economic and animal welfare impacts. The timing of BTV transmission in temperate regions is partly determined by the seasonal presence of adult Culicoides females. Legislative measures therefore allow for the relaxation of ruminant movement restrictions during winter, when nightly light-suction trap catches of Culicoides fall below a threshold (the ‘seasonally vector free period’: SVFP). We analysed five years of time-series surveillance data from light-suction trapping in the UK to investigate whether significant inter-specific and yearly variation in adult phenology exists, and whether the SVFP is predictable from environmental factors. Because female vector Culicoides are not easily morphologically separated, inter-specific comparisons in phenology were drawn from male populations. We demonstrate significant inter-specific differences in Culicoides adult phenology with the season of Culicoides scoticus approximately eight weeks shorter than Culicoides obsoletus. Species-specific differences in the length of the SVFP were related to host density and local variation in landscape habitat. When the Avaritia Culicoides females were modelled as a group (as utilised in the SFVP), we were unable to detect links between environmental drivers and phenological metrics. We conclude that the current treatment of Avaritia Culicoides as a single group inhibits understanding of environmentally-driven spatial variation in species phenology and hinders the development of models for predicting the SVFP from environmental factors. Culicoides surveillance methods should be adapted to focus on concentrated assessments of species-specific abundance during the start and end of seasonal activity in temperate regions to facilitate refinement of ruminant movement restrictions thereby reducing the impact of Culicoides-borne arboviruses

    High--order connected moments expansion for the Rabi Hamiltonian

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    We analyze the convergence properties of the connected moments expansion (CMX) for the Rabi Hamiltonian. To this end we calculate the moments and connected moments of the Hamiltonian operator to a sufficiently large order. Our large--order results suggest that the CMX is not reliable for most practical purposes because the expansion exhibits considerable oscillations.Comment: 12 pages, 5 figures, 1 tabl

    Controls on the composition and lability of dissolved organic matter in Siberia's Kolyma River basin

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    High-latitude northern rivers export globally significant quantities of dissolved organic carbon (DOC) to the Arctic Ocean. Climate change, and its associated impacts on hydrology and potential mobilization of ancient organic matter from permafrost, is likely to modify the flux, composition, and thus biogeochemical cycling and fate of exported DOC in the Arctic. This study examined DOC concentration and the composition of dissolved organic matter (DOM) across the hydrograph in Siberia's Kolyma River, with a particular focus on the spring freshet period when the majority of the annual DOC load is exported. The composition of DOM within the Kolyma basin was characterized using absorbance-derived measurements (absorbance coefficienta330, specific UV absorbance (SUVA254), and spectral slope ratio SR) and fluorescence spectroscopy (fluorescence index and excitation-emission matrices (EEMs)), including parallel factor analyses of EEMs. Increased surface runoff during the spring freshet led to DOM optical properties indicative of terrestrial soil inputs with high humic-like fluorescence, SUVA254, and low SRand fluorescence index (FI). Under-ice waters, in contrast, displayed opposing trends in optical properties representing less aromatic, lower molecular weight DOM. We demonstrate that substantial losses of DOC can occur via biological (∼30% over 28 days) and photochemical pathways (>29% over 14 days), particularly in samples collected during the spring freshet. The emerging view is therefore that of a more dynamic and labile carbon pool than previously thought, where DOM composition plays a fundamental role in controlling the fate and removal of DOC at a pan-Arctic scale

    Stress-induced amorphization at moving crack tips in NiTi

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    In situ fracture studies on thin-film NiTi intermetallic compounds have been carried out in the high-voltage electron microscope at Argonne National Laboratory. Local stress-induced amorphization of regions directly in front of moving crack tips has been observed under tensile loading conditions. The stress-induced amorphization at crack tips exhibits a temperature dependence similar to that of ion-induced amorphization of NiTi. The upper limiting temperature for stress-induced amorphization is the same as that for ion-induced amorphization of crystalline NiTi and for amorphous phase formation during ion-beam mixing of Ni and Ti multilayer specimens. This upper limiting temperature of 600K is also the lowest temperature at which stress-induced amorphous phase crystallizes during isothermal annealing. This isothermal crystallization temperature is nearly 200K less than the kinetic crystallization temperature during heating of unrelaxed NiTi glasses formed by rapid quenching or vapor phase deposition

    Deciphering ocean carbon in a changing world

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    Author Posting. © The Author(s), 2016. This is the author's version of the work. It is posted here for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences of the United States of America 113 (2016): 3143-3151, doi:10.1073/pnas.1514645113.Dissolved organic matter (DOM) in the oceans is one of the largest pools of reduced carbon on Earth, comparable in size to the atmospheric CO2 reservoir. A vast number of compounds are present in DOM and they play important roles in all major element cycles, contribute to the storage of atmospheric CO2 in the ocean, support marine ecosystems, and facilitate interactions between organisms. At the heart of the DOM cycle lie molecular-level relationships between the individual compounds in DOM and the members of the ocean microbiome that produce and consume them. In the past, these connections have eluded clear definition because of the sheer numerical complexity of both DOM molecules and microorganisms. Emerging tools in analytical chemistry, microbiology and informatics are breaking down the barriers to a fuller appreciation of these connections. Here we highlight questions being addressed using recent methodological and technological developments in those fields and consider how these advances are transforming our understanding of some of the most important reactions of the marine carbon cycle.Support was provided by National Science Foundation grants OCE1356010, OCE1154320, and OCE1356890, and Gordon and Betty Moore Foundation Grant #3304

    Differential susceptibility to obesity between male, female and ovariectomized female mice

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    All authors are with the Department of Nutritional Sciences, University of Texas at Austin, Austin, Texas, USABackground: The prevalence of obesity has increased dramatically. A direct comparison in the predisposition to obesity between males, premenopausal females, and postmenopausal females with various caloric intakes has not been made. To determine the effects of sex and ovarian hormones on the susceptibility to obesity, we conducted laboratory studies with mice. To eliminate confounders that can alter body weight gain, such as age and food consumption; we used mice with the same age and controlled the amount of calories they consumed. -- Methods: We determined sex-specific susceptibility to obesity between male, non-ovariectomized female, and ovariectomized female mice. To compare susceptibility to gaining body weight between males and females, animals from each sex were exposed to either a 30% calorie-restricted, low-fat (5% fat), or high-fat (35% fat) diet regimen. To establish the role of ovarian hormones in weight gain, the ovaries were surgically removed from additional female mice, and then were exposed to the diets described above. Percent body fat and percent lean mass in the mice were determined by dual energy x-ray absorptiometry (DEXA). -- Results: In all three diet categories, male mice had a greater propensity of gaining body weight than female mice. However, ovariectomy eliminated the protection of female mice to gaining weight; in fact, ovariectomized female mice mimicked male mice in their susceptibility to weight gain. In summary, results show that male mice are more likely to become obese than female mice and that the protection against obesity in female mice is eliminated by ovariectomy. -- Conclusion: Understanding metabolic differences between males and females may allow the discovery of better preventive and treatment strategies for diseases associated with body weight such as cancer and cardiovascular disease.Nutritional [email protected]
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