582 research outputs found

    Diversity Speakers Series: Unconscious Bias in Academic Medicine

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    Program for Unconscious Bias in Academic Medicine by Wayne A.U. Frederick, MD, MBA: Interim President, Howard Universityhttps://digitalcommons.pcom.edu/diversity_inclusion/1008/thumbnail.jp

    A graphics terminal for a digital computer.

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    A cognitive approach to discharge planning for offenders

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    The paper describes an application of cognitive psychological techniques to a program of discharge planning for offenders from a medium security Correctional Centre. It contains a review of alternative methods of discharge planning, outlines the development of cognitive treatment techniques, and explains the rationale for applying these techniques to incarcerated offenders. A quasi-experimental approach is utilized, comparing a group that experienced a combination of Interpersonal Cognitive Problem-Solving, an affective component, self-initiation and relapse prevention with no treatment comparison groups. A significant improvement was in the experiment group in their ability to solve problems as measured by the Means End Problem-Solving Inventory (Platt & Spivack, 1989). The groups were also compared in their ability to select alternatives as measured by the Social Insight Scale (Cassel, 1976) and their expression of anger and hostility as measured by the Buss-Durkee Scale (Buss, Fisher & Simmons, 1962). While significant results were observed, the results must be viewed with caution. When compared to the control group, the experimental group displayed promising results in terms of recidivism. The complications encountered conducting longitudinal research within a correctional facility are discussed

    A Benthic chamber with electric stirrer mixing

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    Benthic chambers incorporating electric stirrer mixing have been designed and tested and have proven reliable during seven 18-31 day, 4300m ocean deployments. The chambers are 21 cm diameter by 31 cm long acrylic tubes sealed with pvc lids. A stepper motor and pressure tolerant electronics contained within the lids are magnetically coupled to stirring paddles to provide mixing within the chambers. The stirrers exhibit stable mixing rates and uniform speeds between chambers, require less than 1/3 watt of power, and are maintenance free. Laboratory calibration of stirring and mixing characteristics demonstrate that areal averaged equivalent seawater-sediment boundary layer thickness can be set to agree with in situ measured values.Funding was provided by the National Science Foundation through Grant No. OCE87-11962

    Sustainable plant production on degraded soil / substrates amended with South African class F fly ash and organic materials

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    South Africa is a country with very little prime farmland. A large percentage of this high agricultural capability land is generally acidic and nutrient poor, and situated in areas where large coal mining activities occur. Coal mining and agriculture are important industries in South Africa. They impact extensive land areas, and often compete for the same land. The surface mining of coal seriously damages the surface soil, local flora and fauna. Mining wastes viz. overburden, discards and mine effluents, have also created land degradation problems. Three of the most common factors that characterize degraded substrates are soil acidification, nutrient depletion and loss of biological activity. To ensure a healthy and productive vegetation, disturbed soils need to be ameliorated effectively. Using conventional methods is costly and is often not sustainable. The challenge is, therefore, to use potential alternative ameliorants in an economically, ecologically and socially sustainable manner. Fortunately, South Africa has plenty of industrial and organic by-products, which might be used as alternative ameliorants. There is an enormous amount of international literature on the use of class C fly ash, (Sub bitumious or lignite CCB – [Coal combustion byproduct]), and to a lesser extent class F fly ash (Bitumious CCB), as opposed to South African class F fly ash, which is predominantly produced in this country. Fly ash, either by itself, or together with other wastes such as biosolids, can serve as a soil ameliorant by providing a good source of micro-, macronutrients and organic material for the reclamation of land. Previous research has shown that when sewage sludge is mixed with class F fly ash and a suitable source of reactive lime in a specific ratio, sewage sludge pasteurization will occur. The SLudgeASH (SLASH) mixture has been extensively evaluated as a soil ameliorant and has proven to be viable for the reclamation of poor and marginal soils. This study, has focused on the effect of soil ameliorants on the chemical-, physical- and microbiological properties of degraded agricultural land, mine land and other mining wastes (tailings and discards) requiring rehabilitation. This study also evaluated the affects of class F fly ash and SLASH amelioration of soils and substrates on plant production and revegetation, in comparison with conventional liming and fertilization methods currently in use. Species such as maize (Zea mays) and wheat (Triticum aestivum); pasture legumes such as lucerne or alfalfa (Medicago sativa); sub tropical grasses such as Foxtail Buffalo grass (Cenchrus ciliaris), Rhodegrass (Chloris gayana) and Smutsfinger grass (Digitaria erianthra) have been evaluated. The success of enhanced plant production, re- vegetation and sustainability of once degraded soils / substrates is an indication of the amelioration success achieved. Seed germination, root development, plant yield, plant density, botanical diversity and biological activity are parameters which can all be used to support the conclusion that alternative substrate amendment practices can improve the plant growth medium. Based on the results obtained in this study, it was concluded that fly ash and fly ash/organic material mixtures (SLASH) improved soil chemical properties such as pH, ammonium acetate extractable K, Ca, Mg and Bray 1 extractable P levels. All parameters measured were significantly influenced by the fly ash and SLASH. For example, the pH of soils impacted by acid mine drainage was improved by 240% by the use of SLASH. Other results illustrate improvements in soil physical properties such as texture, bulk density, water infiltration rate and hydraulic conductivity, by class F fly ash based soil ameliorants. In addition to the beneficial effects on soil physical properties, the microbial properties were also improved, as indicated by the beneficiation of symbiotic relationship of the Rhizobium bacteria and the important host plant Medicago sativa. Improvements in crop yields, such as: wheat yields on SLASH and fly ash treatments were 270% and 150% better than the control respectively; yields of maize and alfalfa were improved by 130 % and 450% respectively, were also registered. Fly ash and SLASH ameliorated soils resulted in approximately 850%, 266% and 110% higher dry matter production on gold mine tailings, AMD impacted soil and acidic mine cover soil, respectively, relative to the control treatments. Results also clearly illustrated that the abundance of certain species can be related to the higher fertility levels of the rehabilitated soil. Data collected over the past seven years, illustrates how the botanical composition has changed, and that soils receiving class F fly ash and sewage sludge had a higher dry matter production, whereas the control (no treatment) had a better biodiversity. With respect to the reclamation of coal discard materials, significant increases in yield, of up to 200%, were noted for soils and discards treated with class F fly ash, relative to the untreated control. The pH of cover soil was the most strongly affected soil parameter during the experimental period. Class F fly ash and SLASH have the potential to improve the chemical, physical and microbiological properties of degraded soils and substrates. From this experimental work it can be concluded that class F fly ash from Lethabo definitely has a much higher CaCO3 equivalent than what was originally assumed and that other SA sources probably have an even better neutralizing value. Class F fly ash and SLASH, are good sources of micronutrients and some macro nutrients, and may play a significant role in neutralizing acidity due to their residual alkalinity, and thus ability to continuously change the soil chemical balance so that nutrients become more available for plant uptake and use, thereby enhancing growth. Agricultural, domestic and industrial byproducts unfortunately, vary greatly in nutrient content, trace metals and liming potential, and these factors can affect both re-vegetation success and the environmental impact of reclamation. Co-utilization of by-products can often combine beneficial properties of the individual by-products to eventually have a more pronounced effect on the degraded soil or substrate.Thesis (PhD(Pasture Science))--University of Pretoria, 2008.Plant Production and Soil SciencePhDunrestricte

    Development and verification of a laboratory model for use in the study of a continuous flow pressurized activated sludge process

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    Investigations concerning the responses of domestic wastewater treated at elevated pressures have demonstrated an acceleration in the rate of biological assimilation of the waste material. The literature is not extensive, but presents much conflicting data. There has been a lack of a coherent approach to the investigation of pressure in wastewater treatment. This demonstrates the need for standard testing apparatus and procedures. A bench scale pressurized activated sludge process was designed and constructed. The apparatus was tested over a broad range of conditions and was found to give reproducible results. Kinetic responses of the pressurized process are presented

    Weidings in die lente

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    Teen die einde van winter en met die aanbreek van die lente is weidingsbeplanning vir die komende groeiseisoen vir somerreënvalgebiede belangrik. Beplanning en voorbereiding vir 'n droër en warmer somer in die winterreënvalgebiede is egter net so belangrik.http://www.veeplaas.co.za

    Weiding in die winter

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    Ter voorbereiding van die komende winter wil die meeste weidingsboere 'n situasie hê waar: Die meeste natuurlike subtropiese weidings lig bewei word, sodat die plante reserwes kan opbou om vinnig te kan herstel tydens die lentegroeitydperk. Aangeplante weidings al gesny is vir hooi of kuilvoer om die voerbank vir die winter aan te vul wanneer weidingsgehalte in somerreënval en rypgevoelige gebiede laag is. Alle weidings vir staande hooi goeie bemesting en goeie groei gehad het. Gematigde weidings reeds gevestig is indien ekstra grond en voldoende besproeiing beskikbaar was. Bestaande en nuwe weidings in winterreënvalgebiede gevestig is en goed bemes is.http://www.veeplaas.co.za

    Myns insiens ... beplan jou herfsmaande

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    Weidingsbestuur is ’n filosofie. Jy kan resepte hê, maar enige bestuur op ’n plaas is omgewingspesifiek. Dit beteken jy moet jou aksies aanpas binne ’n filosofiese raamwerk. As ’n mens na die situasie in die land kyk, is dit moeilik om reëls neer te lê wat oral geld. Kom ons aanvaar dus dat elke boer op grond van sy eie situasie hierdie riglyne sal aanpas.http://www.veeplaas.co.za
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