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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Evaluering van die Vienna toetsbattery in die voorspelling van effektiewe busbestuurder gedrag

Du Toit, Martina Petronella 30 November 2006 (has links)
Vehicle accidents by means of Public transport annually leads to a large number of passenger deaths and life long disablement. AsDu Toit, Martina Petronella a result, there is a need for preventative measures by identifying the psychomotor abilities of bus drivers during the recruitment and selection process of employment. The study was conducted among 398 bus drivers employed by a large bus company. The Vienna Test Battery was administered. It was found that distance estimation, ability to recognize forms and figures, concentration ability, eye-hand feet coordination and two-hand coordination predicted the effectiveness of bus drivers successfully. It is suggested that further research should focus on client services, attitude of bus drivers and learning potential, as factors that influence the effectiveness of bus drivers. / Industrial psychology / M.A. (Industrial Psychology)
42

Predictive Relations Between Cognitive Abilities and Pilot Performance: A Structural Equation Modeling Approach

Khalid S. Almamari (5930516) 31 July 2020 (has links)
<p></p><p>A large body of literature suggests that cognitive abilities are important determinants for training and job performance, including flight performance. The associations between measures of ability tests and job performance have been the focus of many empirical studies, resulting in an overall conclusion that general mental ability, <i>g</i>, is the main source of prediction, while other narrower abilities have limited power for predicting job performance. Despite the attention given to cognitive ability-flight performance relationships, their associations have not been fully understood at the broad construct level, and most extant literature focused on the relations at the observed scores level. Thus, the present dissertation study was designed to contribute to the progression of this understanding by examining the relations between cognitive abilities and flight training performance, using data from four U.S. Air Force (USAF) pilot samples. For comparison, one navigator and one air battle manager sample were also analyzed. The data were obtained from correlation matrices of prior investigations and analyzed via structural equation modeling (SEM) procedures. </p> <p> Four studies are reported in the thesis: (1) preliminary study, (2) primary validation study, (3) cross-validation study, and (4) cross-occupation validation study. The preliminary study assessed the test battery used in the subsequent predictive studies. The primary validation study introduced a bifactor predictive SEM model for testing the influence of cognitive abilities in predicting pilot performance. The cross-validation study assessed the consistency of the predictive model suggested in the primary validation study, using three additional pilots’ samples. The cross-occupation validation study compared the predictive model using data from three aviation-related occupations (flying, navigation, air battle management). Ability factors were extracted from scores of pilot applicants on the Air Force Officer Qualifying Test (AFOQT), the USAF officers’ primary selection test battery, whereas the flight performance scores were obtained from pilot records during the flight training program.</p> <p> In addition to the <i>g</i> factor, <i>verbal ability, quantitative ability, spatial ability, perceptual speed ability, and aviation-related acquired knowledge </i>are the six latent cognitive ability factors investigated in the reported studies. Pilot performance measures were modeled either as observed or latent variables covering ratings of academic and hands-on flying performance in different phases of the training program. The studies of this thesis established that (1) general ability contributes substantially to the prediction models; however, it is not the only important predictor, (2) aviation-related acquired knowledge is the most robust predictor of pilot performance among the abilities examined, with a role even exceeding that of <i>g</i>, (3) perceptual speed predicted pilot performance uniquely in several occasions, while verbal, spatial, and quantitative abilities demonstrated trivial incremental validity for hands-on pilot performance beyond that provided by the <i>g</i> measure, and (4) the relative importance of cognitive abilities tends to vary across aviation occupations.</p><br><p></p>
43

Development of Sensitive In Vitro Assays to Assess the Ocular Toxicity Potential of Chemicals and Ophthalmic Products

McCanna, David January 2009 (has links)
The utilization of in vitro tests with a tiered testing strategy for detection of mild ocular irritants can reduce the use of animals for testing, provide mechanistic data on toxic effects, and reduce the uncertainty associated with dose selection for clinical trials. The first section of this thesis describes how in vitro methods can be used to improve the prediction of the toxicity of chemicals and ophthalmic products. The proper utilization of in vitro methods can accurately predict toxic threshold levels and reduce animal use in product development. Sections two, three and four describe the development of new sensitive in vitro methods for predicting ocular toxicity. Maintaining the barrier function of the cornea is critical for the prevention of the penetration of infections microorganisms and irritating chemicals into the eye. Chapter 2 describes the development of a method for assessing the effects of chemicals on tight junctions using a human corneal epithelial and canine kidney epithelial cell line. In Chapter 3 a method that uses a primary organ culture for assessing single instillation and multiple instillation toxic effects is described. The ScanTox system was shown to be an ideal system to monitor the toxic effects over time as multiple readings can be taken of treated bovine lenses using the nondestructive method of assessing for the lens optical quality. Confirmations of toxic effects were made with the utilization of the viability dye alamarBlue. Chapter 4 describes the development of sensitive in vitro assays for detecting ocular toxicity by measuring the effects of chemicals on the mitochondrial integrity of bovine cornea, bovine lens epithelium and corneal epithelial cells, using fluorescent dyes. The goal of this research was to develop an in vitro test battery that can be used to accurately predict the ocular toxicity of new chemicals and ophthalmic formulations. By comparing the toxicity seen in vivo animals and humans with the toxicity response in these new in vitro methods, it was demonstrated that these in vitro methods can be utilized in a tiered testing strategy in the development of new chemicals and ophthalmic formulations.
44

Development of Sensitive In Vitro Assays to Assess the Ocular Toxicity Potential of Chemicals and Ophthalmic Products

McCanna, David January 2009 (has links)
The utilization of in vitro tests with a tiered testing strategy for detection of mild ocular irritants can reduce the use of animals for testing, provide mechanistic data on toxic effects, and reduce the uncertainty associated with dose selection for clinical trials. The first section of this thesis describes how in vitro methods can be used to improve the prediction of the toxicity of chemicals and ophthalmic products. The proper utilization of in vitro methods can accurately predict toxic threshold levels and reduce animal use in product development. Sections two, three and four describe the development of new sensitive in vitro methods for predicting ocular toxicity. Maintaining the barrier function of the cornea is critical for the prevention of the penetration of infections microorganisms and irritating chemicals into the eye. Chapter 2 describes the development of a method for assessing the effects of chemicals on tight junctions using a human corneal epithelial and canine kidney epithelial cell line. In Chapter 3 a method that uses a primary organ culture for assessing single instillation and multiple instillation toxic effects is described. The ScanTox system was shown to be an ideal system to monitor the toxic effects over time as multiple readings can be taken of treated bovine lenses using the nondestructive method of assessing for the lens optical quality. Confirmations of toxic effects were made with the utilization of the viability dye alamarBlue. Chapter 4 describes the development of sensitive in vitro assays for detecting ocular toxicity by measuring the effects of chemicals on the mitochondrial integrity of bovine cornea, bovine lens epithelium and corneal epithelial cells, using fluorescent dyes. The goal of this research was to develop an in vitro test battery that can be used to accurately predict the ocular toxicity of new chemicals and ophthalmic formulations. By comparing the toxicity seen in vivo animals and humans with the toxicity response in these new in vitro methods, it was demonstrated that these in vitro methods can be utilized in a tiered testing strategy in the development of new chemicals and ophthalmic formulations.

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