10,220 research outputs found
Modelling the speciation and biogeochemistry of iron in oceanic surface waters at the Bermuda Atlantic Time-series Study site
No full textBy means of numerical modelling the cycling of iron between its various physical (dissolved, colloidal, particulate) and chemical (redox state and organic complexation) forms in the upper mixed layer of the ocean is analysed. Using the model an initial quantitative assessment is made of how this cycling influences iron uptake by phytoplankton and its loss via particulate export. The model is forced with observed dust deposition rates, mixed layer depths, and solar radiation at the site of the Bermuda Atlantic Timeseries Study (BATS). It contains an optimised ecosystem model which yields results close to the observational data from BATS.Firstly, the results of a zero-dimensional model approach show that the mixed layer cycle strongly influences the cycling of iron between its various forms. This was mainly attributed to the light dependency of photoreductive processes and to the seasonality of primary production. The daily photochemical cycle is driven primarily by the production of superoxide and its amplitude depends on the concentration and speciation of dissolved copper. Model results are largely insensitive to the dominant form of dissolved iron introduced via dust deposition, and also to the form of iron that is taken up directly during algal growth. In the model solutions, the role of the colloidal pumping mechanism depends strongly on assumptions made regarding rates of colloid aggregation and photoreduction rate.Secondly, a one-dimensional approach of the model is coupled with the General Ocean Turbulence Model (GOTM). The combined model was able to simulate the temporal patterns and vertical profiles of dissolved iron in the upper ocean at the BATS site reasonably well. Subsurface model profiles depended strongly on the parameter values chosen for loss processes affecting iron, colloidal aggregation and scavenging onto particles. Current estimates for these parameters result in depletion of dFe. A high stability constant of iron-binding organic ligands is required to reproduce the observed degree of organic complexation below the mixed layer. Solubility of atmospherically deposited iron higher than 2% leads to dissolved iron concentrations higher than observations. Despite neglecting ultraviolet radiation, the model produces diurnal variations and mean vertical profiles of dFe which are in good agreement with observations
The Thomas Iron Company, charters and supplements : together with the enabling acts of New Jersey
No full textThe documents in this collection begin with the charter that outlines the incorporation of the Thomas Iron Company enacted by the Senate and House of Representatives of the Commonwealth of Pennsylvania in 1854. Supplements to this Act are also included which discuss topics such as capital stock, elections, the building of railroads by the Thomas Iron Company, coal mining and the use of mineral lands, buying and selling of land, and purchases of other companies. Also included are the Acts of the Legislature of New Jersey which allows the Thomas Iron Company to hold land and real estate in New Jersey, as well as mineral lands in New Jersey, and finally, to build a railroad from their mines to the Ogden Mine Railroad
Adsorptive iron removal from groundwater
No full text Iron is commonly present in groundwater worldwide. The presence of iron in the water supply is not harmful to human health, however it is undesirable. Bad taste, discoloration, staining, deposition in the distribution system leading to aftergrowth, and incidences of high turbidity are some of the aesthetic and operational problems associated with iron in water supplies. Iron removal from groundwater is, therefore, a major concern for water supply companies using groundwater sources. The WHO recommended guideline value of iron in drinking water is 0.3 mg/l and the EC directive has set a parametric value of 0.2 mg/1. In the Netherlands, the guideline value of iron in drinking water is≤0.05mg/1 and several Dutch water supply companies are aiming at iron concentrations below 0.03 mg/1 to minimise distribution network maintenance costs. Of the different methods available to control iron in water supplies (oxidation-filtration, ion exchange, lime softening, sub-surface iron removal, and sequestration), aeration followed by rapid sand filtration is the most commonly used. Different mechanisms (physical, chemical, and biological) may contribute to the removal of iron in filters and the dominant mechanism depends on water quality and process conditions applied. Fig. 8. 1 summarises the different mechanisms of iron removal in filters and the steps involved. Under anoxic conditions, adsorption is the only mechanism of iron removal from groundwater. In the presence of oxygen, iron removal can take place via three different mechanisms, namely i) oxidation-floe formation (floe filtration), ii) biological oxidation, and iii) adsorption-oxidation (adsorptive filtration). Under the commonly applied treatment conditions in iron removal plants, the oxidation-floe formation mechanism is commonly believed to be dominant. The adsorptionoxidation mechanism (adsorptive iron removal), however, has several potential advantages over the oxidation-floe formation mechanism, namely longer filter run, shorter filter ripening time, and less backwash water use and sludge production.</p
Heme iron from meat and risk of colorectal cancer: a meta-analysis and a review of the mechanisms involved
Get PDFRed meat and processed meat intake is associated with a risk of colorectal cancer, a major cause of death in affluent countries. Epidemiological and experimental evidence supports the hypothesis that heme iron present in meat promotes colorectal cancer. This meta-analysis of prospective cohort studies of colon cancer reporting heme intake included 566,607 individuals and 4,734 cases of colon cancer. The summary relative risk of colon cancer was 1.18 [95%C.I.: 1.06-1.32] for subjects in the highest category of heme iron intake compared with those in the lowest category. Epidemiological data thus show a suggestive association between dietary heme and risk of colon cancer. The analysis of experimental studies in rats with chemically-induced colon cancer showed that dietary hemoglobin and red meat consistently promote aberrant crypt foci, a putative pre-cancer lesion. The mechanism is not known, but heme iron has a catalytic effect on (i) the endogenous formation of carcinogenic N-nitroso compounds and (ii) the formation of cytotoxic and genotoxic aldehydes by lipoperoxidation. A review of evidence supporting these hypotheses suggests that both pathways are involved in heme iron toxicit
O pensamento de Max Weber na literatura internacional: Um estudo temático da produção de seus comentadores a partir do Portal de Periódicos EBSCOhost.
Get PDFTCC (graduação) - Universidade Federal de Santa Catarina, Centro de Filosofia e Ciências Humanas, Curso de Ciências Sociais.Este trabalho apresenta o conjunto dos resultados obtidos entre os anos de 2009 e 2012, na investigação que objetivou elaborar um retrato do debate em torno do pensamento de Max Weber na produção intelectual repercutida em vários países, a partir de autores que abordam diretamente sua obra. A pesquisa bibliográfica foi feita por meio da internet, a partir do Portal de Periódicos EBSCOhost, uma plataforma de busca internacional que abarca, além de outras publicações, os artigos encontrados no Portal Capes. Destarte, sob o critério de abordar apenas textos que tratavam diretamente sobre Weber ou sobre a obra de Weber, selecionamos – dentre aproximadamente dois mil resultados obtidos – o número de 458 artigos publicados em periódicos internacionais, que cobrem o período de 1934 a 2012. O material foi posteriormente classificado através da leitura instrumental prévia dos resumos desses artigos e da sistematização em eixos, dos quais se obtêm três categorias, a saber: 1) grupo temático, conforme as áreas da produção weberiana (Política, Direito, Modernidade, etc.); 2) ano de publicação; 3) idioma em que o trabalho foi publicado. Como um quadro geral, podemos afirmar que a reflexão crítica sobre o pensamento de Max Weber cresce de maneira considerável. A produção em torno de sua obra ganha em projeção e vigor no avanço temporal. Esforços, debates e discussões empreendidos pelos examinadores da obra de Weber, no intuito de “desvendar” aspectos minuciosos e específicos dentro dessa obra, apresentam-se como indicativos do aprofundamento das interpretações e do alargamento do olhar em torno do conjunto da produção weberiana. Sem temor, é possível afirmar que Max Weber é um autor longe do desgaste e que recebe cada vez mais atenção analítica. A realização deste trabalho oferece uma rota possível de introdução ao pensamento weberiano, e a leitura e sistematização desse material, a partir de seus comentadores, estima criar inteligibilidade para o assunto
O pensamento de Max Weber na literatura internacional: um estudo temático da produção de seus comentadores a partir do Portal de Periódicos EBSCOhost
Get PDFTCC (graduação) - Universidade Federal de Santa Catarina, Centro de Filosofia e Ciências Humanas, Curso de Ciências Sociais.Este trabalho apresenta o conjunto dos resultados obtidos entre os anos de 2009 e 2012, na investigação que objetivou elaborar um retrato do debate em torno do pensamento de Max Weber na produção intelectual repercutida em vários países, a partir de autores que abordam diretamente sua obra. A pesquisa bibliográfica foi feita por meio da internet, a partir do Portal de Periódicos EBSCOhost, uma plataforma de busca internacional que abarca, além de outras publicações, os artigos encontrados no Portal Capes. Destarte, sob o critério de abordar apenas textos que tratavam diretamente sobre Weber ou sobre a obra de Weber, selecionamos – dentre aproximadamente dois mil resultados obtidos – o número de 458 artigos publicados em periódicos internacionais, que cobrem o período de 1934 a 2012. O material foi posteriormente classificado através da leitura instrumental prévia dos resumos desses artigos e da sistematização em eixos, dos quais se obtêm três categorias, a saber: 1) grupo temático, conforme as áreas da produção weberiana (Política, Direito, Modernidade, etc.); 2) ano de publicação; 3) idioma em que o trabalho foi publicado. Como um quadro geral, podemos afirmar que a reflexão crítica sobre o pensamento de Max Weber cresce de maneira considerável. A produção em torno de sua obra ganha em projeção e vigor no avanço temporal. Esforços, debates e discussões empreendidos pelos examinadores da obra de Weber, no intuito de “desvendar” aspectos minuciosos e específicos dentro dessa obra, apresentam-se como indicativos do aprofundamento das interpretações e do alargamento do olhar em torno do conjunto da produção weberiana. Sem temor, é possível afirmar que Max Weber é um autor longe do desgaste e que recebe cada vez mais atenção analítica. A realização deste trabalho oferece uma rota possível de introdução ao pensamento weberiano, e a leitura e sistematização desse material, a partir de seus comentadores, estima criar inteligibilidade para o assunto
Ischaemic strokes in patients with pulmonary arteriovenous malformations and hereditary hemorrhagic telangiectasia: associations with iron deficiency and platelets.
Get PDF25/03/14 meb. OA paper , Ok to add.Background: Pulmonary first pass filtration of particles marginally exceeding ~7 µm (the size of a red blood cell) is used routinely in diagnostics, and allows cellular aggregates forming or entering the circulation in the preceding cardiac cycle to lodge safely in pulmonary capillaries/arterioles. Pulmonary arteriovenous malformations compromise capillary bed filtration, and are commonly associated with ischaemic stroke. Cohorts with CT-scan evident malformations associated with the highest contrast echocardiographic shunt grades are known to be at higher stroke risk. Our goal was to identify within this broad grouping, which patients were at higher risk of stroke.
Methodology: 497 consecutive patients with CT-proven pulmonary arteriovenous malformations due to hereditary haemorrhagic telangiectasia were studied. Relationships with radiologically-confirmed clinical ischaemic stroke were examined using logistic regression, receiver operating characteristic analyses, and platelet studies.
Principal Findings: Sixty-one individuals (12.3%) had acute, non-iatrogenic ischaemic clinical strokes at a median age of 52 (IQR 41–63) years. In crude and age-adjusted logistic regression, stroke risk was associated not with venous thromboemboli or conventional neurovascular risk factors, but with low serum iron (adjusted odds ratio 0.96 [95% confidence intervals 0.92, 1.00]), and more weakly with low oxygen saturations reflecting a larger right-to-left shunt (adjusted OR 0.96 [0.92, 1.01]). For the same pulmonary arteriovenous malformations, the stroke risk would approximately double with serum iron 6 µmol/L compared to mid-normal range (7–27 µmol/L). Platelet studies confirmed overlooked data that iron deficiency is associated with exuberant platelet aggregation to serotonin (5HT), correcting following iron treatment. By MANOVA, adjusting for participant and 5HT, iron or ferritin explained 14% of the variance in log-transformed aggregation-rate (p = 0.039/p = 0.021).
Significance: These data suggest that patients with compromised pulmonary capillary filtration due to pulmonary arteriovenous malformations are at increased risk of ischaemic stroke if they are iron deficient, and that mechanisms are likely to include enhanced aggregation of circulating platelets
Weber and church governance: religious practice and economic activity
No full textThe debate about the relationship between religion and economic activity in the wake of Weber has been cast largely in terms of belief and values. This article suggests an alternative focus on practice. It argues that taken for granted practices of church governance formed to-hand resources for the organization of economic activity. The argument is developed through an examination of the historical development of church governance practices in the Presbyterian Church of Scotland, with particular emphasis on the way in which theological belief gave rise to practices of accountability and record keeping. In turn such practices contributed to a ‘culture of organization’ which had implications for economic activity. A focus on governance practices can help to illuminate enduring patterns of difference in the organization of economic activity
Elective affinities of the Protestant ethic : Weber and the chemistry of capitalism
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