418 research outputs found

    Quantitative determination of modal content and morphological properties of coal sulphides by digital image analysis as a tool to check their flotation behaviour

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    An efficient depression of coal sulphides in the flotation process means a healthier environment and may be essential for the sustainability of a coal operation. Nitric and ferric oxidative pre-treatment of coal pyrite have been tested to improve pyrite depression, and the results are compared with those from the process of raw, not pre-treated coal. The removal indexes point to nitric pre-treatment as the best, but depression is still low. The microscopic study of feed and products, coupled to Digital Image Analysis (DIA) in all the cases, provide important clues to understand the behaviour of pyrite, which can be related to quantitative parameters, such as the exposition ratio (ER), and to qualified interpretation of the textures. Pyrite shows in the first float an unexpected hydrophobic behaviour, which is due to its occurrence as framboids, or porous particles which may be intergrown with organic matter and behave as coal. In general, the flotation results can be predicted from the DIA-data, e.g. depression of liberated pyrite into the tailings, increased by oxidative pre-treatments by 300% (ferric) or by > 400% (nitric); or concentration of middlings with lower pyrite ER in the floats. DIA is an efficient tool to obtain some important quantitative informations which otherwise would be inaccessible (e.g. the morphological data on > 1,000,000 pyrite particles for this study), and its use should be enhanced to check ore processing

    Proceedings of a Summer Institute in Water Resources: Volume 1 - Philosophical, Institutional, and Legal Aspects of Water Resources

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    Foreward: Recognizing the need for training of individuals to meet the rapidly rising problems connected with water resources development, Utah State University, with National Science Foundation support, organized a Summer Institute in Water Resources for college teachers. it was hoped that participants carefully selected from all regions of the country would receive additional insight and stimulation to improve and enlarge water resources training programs at their own institutions. Thus, the accelerated dissemination of such knowledge on a national scale could be facilitated. Realizing further that the key to a successful institute of this nature lay in the excellence of its staff, efforts were made to obtain instructors with intimate knowledge and broad experience int he subject matter area they were asked to rpesent. In nearly every case those selected willingly accepted the invitation to participate, although this meant considerable monetary sacrifice and major adjustment of busy schedules. The subject matter treated paralleled regular offerings listed in the University catalog and is considered to be central or core to a water resources planning and management training program. one course treated the philosophical, historical, institutional, political, and legal aspects of water development. The responsibility for this course was shared jointly with Cleve H. Milligan, Charles E. Corker, and Wayne D. Criddle. The second course considered the principles of water resources economics and was presented by B. Delworth Gardner. The third course dealt with concepts of water quality management and was under the direction of P. H. McGauhey. The final course was on principles and procedures of regional resources planning and was presented jointly by Aaron Wiener, W. R. Derrick Sewell, and Harvey O. Banks. Having assembled a distinguished and diversified staff to present some of the best current professional thinking in the topics suggested in the preceding paragraph, it was felt most appropriate to attempt to put their lectures into writing. A proceedings of the Institute would have considerable utility beyong the Institute itself. Hence, the instructors were encouraged to prepare written material for the proceedings and were given secretarial and other assistance to aid them. This material has been organized according to the four major courses and is issued in four comanion volumes. Clearly, this has been a prodigious effort which required Institute staff and others to go the extra mile. Special thanks and recognition are due Mrs. Dorothy Riley who not only typed the entire proceedings but also attended to many details necessary for the successfult operations of the Institute. Jay M. Bagley served as director of the Institute and assumed a general coordinating and editing role in the development of these proceedings

    Keeping mitochondria happy - benefits of a pore choice in acute pancreatitis

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    Mitochondrial dysfunction is a key feature of multiple diseases and thus protection of this organelle is an important therapeutic objective. The pancreatic acinar cell, which synthesises and stores digestive enzyme precursors, is the most abundant cell type in pancreatic tissue and considered to be the primary site of acute pancreatitis (AP) initiation. Early investigations at the University of Liverpool and by others discovered that precipitants of AP, including bile acids and alcohol non‐oxidative metabolites, disrupt calcium signalling in acinar cells leading to toxicity. Sustained cytosolic calcium elevations raise mitochondrial matrix calcium, triggering the opening of the mitochondrial permeability transition pore (MPTP), which results in a loss of membrane potential and ATP production vital for cellular processes (Criddle et al . 2006; Mukherjee et al . 2016) (Fig. 1). The prime consequence of pancreatic mitochondrial dysfunction in AP is necrotic cell death, the extent of which is a major determinant of clinical outcome. Subsequent studies have shown that calcium‐dependent mitochondrial dysfunction in response to AP precipitants also occurs in ductal cells, widening the cast of players implicated in the development of AP (Hegyi & Petersen, 2013). There is currently no specific therapy for the disease and protection of mitochondria by MPTP inhibition is considered a promising therapeutic approach

    Estimates of Consumptive-Use and Irrigation Water Requirements of Crops in Oklahoma

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    The Oklahoma Agricultural Experiment Station periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311

    Referrals for proliferative diabetic retinopathy from two UK diabetic retinopathy screening services: a 10-year analysis of visual outcomes, requirement for vitrectomy, and mortality

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    \ua9 The Author(s) 2024. Background/objectives: To determine long-term outcomes of patients referred with proliferative diabetic retinopathy (PDR) from diabetic eye screening programmes (DESP) to tertiary care centres in the United Kingdom (UK). Methods: Retrospective multicentre study of patients referred from two DESPs in the UK over a 36-month period (2007–9) and followed-up for 10 years. Critical outcomes included severe vision loss (SVL) and the need for vitrectomy. Other outcomes assessed included moderate vision loss (MVL), and patient survival time. Univariate and multiple variable Cox proportional hazards regressions were used to analyse survival outcomes. Results: 212 eyes of 150 patients were referred with a diagnosis of PDR. 109 eyes of 72 patients were confirmed to have active PDR and included in the study. 61% of patients had low-risk PDR, while 39% exhibited high-risk features in at least one eye. Eight (7.3%) eyes developed SVL and 16 (14.7%) MVL during follow up. Vitrectomy was required in 24% (95% CI: 15 to 31%) of all PDR eyes and was most commonly performed for vitreous haemorrhage (65%). The 10-year survival in all PDR patients was 76% (95% CI: 63 to 85%) with the mean time to death for all deceased patients being 5.4 \ub1 3.6 years. On multivariable analysis, only age was found to have a significant association with the survival of patients with PDR. Conclusions: During the 10 year follow up SVL was uncommon, but MVL occurred in almost one-fifth of the eyes. Approximately 1 in 4 eyes required vitrectomy, highlighting its significance in patient management

    Utility of serum procalcitonin values in patients with acute exacerbations of chronic obstructive pulmonary disease: a cautionary note

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    Background: Serum procalcitonin levels have been used as a biomarker of invasive bacterial infection and recently have been advocated to guide antibiotic therapy in patients with chronic obstructive pulmonary disease (COPD). However, rigorous studies correlating procalcitonin levels with microbiologic data are lacking. Acute exacerbations of COPD (AECOPD) have been linked to viral and bacterial infection as well as noninfectious causes. Therefore, we evaluated procalcitonin as a predictor of viral versus bacterial infection in patients hospitalized with AECOPD with and without evidence of pneumonia. Methods: Adults hospitalized during the winter with symptoms consistent with AECOPD underwent extensive testing for viral, bacterial, and atypical pathogens. Serum procalcitonin levels were measured on day 1 (admission), day 2, and at one month. Clinical and laboratory features of subjects with viral and bacterial diagnoses were compared.Results: In total, 224 subjects with COPD were admitted for 240 respiratory illnesses. Of these, 56 had pneumonia and 184 had AECOPD alone. A microbiologic diagnosis was made in 76 (56%) of 134 illnesses with reliable bacteriology (26 viral infection, 29 bacterial infection, and 21 mixed viral bacterial infection). Mean procalcitonin levels were significantly higher in patients with pneumonia compared with AECOPD. However, discrimination between viral and bacterial infection using a 0.25 ng/mL threshold for bacterial infection in patients with AECOPD was poor. Conclusion: Procalcitonin is useful in COPD patients for alerting clinicians to invasive bacterial infections such as pneumonia but it does not distinguish bacterial from viral and noninfectious causes of AECOPD

    Groundwater Development in Arid Basins

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    Summary: Groundwater development frequently provides a means whereby tremendous new economic opportunities are opened up. If supplies are overdrawn (mined) the ensuing regional economy may be able to affort replacements from more costly sources. In the United States the Salt River Valley of Arizona and the valleys of California provide examples. Two cases are treated in this paper, Israel and West Pakistan. In Israel, besides furnishing more than half of the basic source of water suppply, groundwater development provides opportunity for both quantity and quality management, which makes possible use of surface supplies and reclaimed sewage as firm rather than marginal sources. This development will permit the total water resources of this small country, where agricultural production ranks among the world\u27s most efficient, to be utilized effectively down to almost the last drop by the mid 1970\u27s. Israel must then look to desalted water from the sea for further expansion of its overall water supply. In West Pakistan a combination of level terrain and leaky canals since about 1890 led to threatened waterlogging and salinity of more than 25 million acreas of irrigated land, even though supplies were less than half adequate for good productivity. By the 1950\u27s low yields and increasing population threatened starvation. However, initiation of groundwater development, first by the government and later by pricate entreprise, has, since 1960, let to construction of 3,500 governmental tube wells of about 3 cfs capacity and 30,000 private tube wells of slightly less than 1 cfs capacity. Results have been dramatic. Agricultural production and use of fertilizer are rapidly increasing, and opening of well development of pricate enterprise is providing the irrigator with benefits of free competition for his water custom which he did not previously enjoy. Ultimately, besides providing full supplies for an estimated 26 to 30 million acrea, drainage and salinity problems will be mitigated if about 50 million acre-feet are pumped each year from groundwater including about 28 million acre-feet to be mined from a reserve of about 1,900 million acre-feet. With some difficult surface storage development due to terrain, mining may eventually be reduced. Through an eventual technological solution for the continuing overdraft is not now in sight, perhaps an economy may be built which can affort such a solution when the time comes

    Towards a framework for critical citizenship education

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    Increasingly countries around the world are promoting forms of "critical" citizenship in the planned curricula of schools. However, the intended meaning behind this term varies markedly and can range from a set of creative and technical skills under the label "critical thinking" to a desire to encourage engagement, action and political emancipation, often labelled "critical pedagogy". This paper distinguishes these manifestations of the "critical" and, based on an analysis of the prevailing models of critical pedagogy and citizenship education, develops a conceptual framework for analysing and comparing the nature of critical citizenship
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