In the evaluation of special populations, such as neonates, infants and malingerers, audiologist often have to rely heavily on objective measurements to assess hearing ability. Current objective audiological procedures such as tympanometry, the acoustic reflex, auditory brainstem response and transient evoked otoacoustic emissions, however, have certain limitations, contributing to the need of an objective, non¬invasive, rapid, economic test of hearing that evaluate hearing ability in a wide range of frequencies. The purpose of this study was to investigate distortion product otoacoustic emissions (DPOAEs) as an objective test of hearing. The main aim was to attempt to predict hearing ability at 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz with DPOAEs and artificial neural networks (ANNs) in normal and hearing-impaired ears. Other studies that attempted to predict hearing ability with DPOAEs and conventional statistical methods were only able to distinguish between normal and impaired hearing. Back propagation neural networks were trained with the pattern of all present and absent DPOAE responses of 11 DPOAE frequencies of eight DP Grams and pure tone thresholds at 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz. The neural network used the learned correlation between these two data sets to predict hearing ability at 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz. Hearing ability was not predicted as a decibel value, but into one of several categories spanning 10-15dB. Results indicated that prediction accuracy of normal hearing was 92% at 500 Hz, 87% at 1000 Hz, 84% at 2000 Hz and 91% at 4000 Hz. The prediction of hearing-impaired categories was less satisfactory, due to insufficient data for the ANNs to train on. The variables age and gender were included in some of the neural network runs to determine their effect on the distortion product. Gender had only a minor positive effect on prediction accuracy, but age affected prediction accuracy considerably in a positive way. The effect of the amount of data that the neural network had to train on was also investigated. A prediction versus ear count correlation strongly suggested that the inaccurate predictions of hearing-impaired categories is not a result of an inability of DPOAEs to predict pure tone thresholds in hearing impaired ears, but a result of insufficient data for the neural network to train on. This research concluded that DPOAEs and ANNs can be used to accurately predict hearing ability within 10dB in normal and hearing-impaired ears from 500 Hz to 4000 Hz for hearing losses of up to 65dB HL. / Dissertation (MCommunication Pathology)--University of Pretoria, 2009. / Speech-Language Pathology and Audiology / unrestricted

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Submitted by Patrícia Valim Labres de Freitas (patricial) on 2016-03-30T19:29:12Z No. of bitstreams: 1 Gustavo Adami.pdf: 2445130 bytes, checksum: d010b74234328835418d4d0ff2a01f40 (MD5) / Made available in DSpace on 2016-03-30T19:29:12Z (GMT). No. of bitstreams: 1 Gustavo Adami.pdf: 2445130 bytes, checksum: d010b74234328835418d4d0ff2a01f40 (MD5) Previous issue date: 2015-12-23 / Nenhuma / Características existentes no processo de produção da indústria de fluxo contínuo, particularmente a petroquímica, requerem que a medição de eficiência inclua características diferentes da indústria de produção intermitente, tais como a maneira de quantificação dos produtos finais e a natureza das perdas que são consideradas no cálculo da eficiência de produção. Indicadores de eficiência global de produção tipicamente são derivados do OEE (Overall Effective Equipment), proposto por Nakajima (1988) para a indústria de produção intermitente e, por vezes, são utilizados em indústrias de produção contínua sem uma análise prévia de suas limitações. Doze indicadores identificados na literatura foram analisados e comparados com características do processo de produção da indústria petroquímica, obtidos a partir da revisão teórica e de entrevistas com profissionais e pesquisadores dessa indústria. Dessa análise identificou-se que o indicador OAE (Overall Asset Efficiency) apresenta maior aderência em relação à classificação de perdas e às características do processo de manufatura da indústria petroquímica. Os resultados de eficiência global de produção obtidos através da utilização do OAE foram confrontados com os provenientes do OEE e do TEEP (Total Effective Equipment Productivity), com base em dados reais de uma empresa localizada no Pólo Petroquímico do Rio Grande do Sul. Os resultados obtidos através do cálculo de eficiência utilizando o indicador selecionado OAE, se mostraram mais descritivos da realidade da empresa quando comparados com aqueles atualmente utilizados. Outras práticas que geram interferências sobre o cálculo do OEE também foram identificadas nas entrevistas. Ainda, foi identificada a necessidade de uma discussão mais ampla no sentido de melhor definir os conceitos de capacidade e nível de atividade na indústria petroquímica e sua estimação operacional para fins de análise de eficiência, bem como, a incorporação de termos relativos à eficiência de insumos e custeio na análise de eficiência operacional global dessa indústria. / Due to singular characteristics present in the production of continuous flow process industry, especially petrochemical, efficiency measurement require different features of intermittently producing industry, such as how to quantify the final products and the cause of the losses that are considered in the calculation of production efficiency. Production efficiency indicators are typically derived from the OEE (Overall Equipment Effective) proposed by Nakajima (1988) for intermittent production industry, they are sometimes used in continuous manufacturing industries without a prior analysis of their limitations. Twelve indicators identified in the literature were analyzed and compared with features of the petrochemical industry production process, obtained from theoretical review and interviews with professionals and researchers in this industry. This analysis identified that the indicator OAE (Overall Asset Efficiency) has a better production losses structure and fits the characteristics of petrochemical manufacturing process. The results of overall production efficiency obtained using the OAE were compared with results from OEE and TEEP (Total Effective Equipment Productivity), based on manufacturing data from a company located in Rio Grande do Sul petrochemical complex. The results obtained from the efficiency calculation utilizing the selected indicator OAE, are more descriptive of the company situation when compared to those currently used. Other practices that causes interference on the calculation of OEE were also identified in the interviews. It was also identified the necessity for a broader discussion in order to better define the concepts of capacity and activity level in the petrochemical industry and also the operational way define them in order to make analysis of efficiency as well as the incorporation of terms concerning the efficiency of inputs and costing the analysis of overall operational efficiency of this industry.

Noise exposure is one of the most prevalent causes of irreversible occupational disease in Sweden and in many other countries. In hearing conservation programs, aimed at preventing noise-induced hearing loss, audiometry is an important instrument to highlight the risks and to assess the effectiveness of the program. A hazardous working environment and persons affected by it can be identified by monitoring the hearing thresholds of individual employees or groups of employees over time. However, in order to evaluate the prevalence of occupational noise-induced hearing loss, relevant reference data of unexposed subjects is needed. The first part of this dissertation concerns the changes in hearing thresholds over three decades in two occupational environments with high noise levels in the province of Östergötland, Sweden: the mechanical and the wood processing industries. The results show a positive trend, with improving median hearing thresholds from the 1970s into the 1990s. However, the hearing loss present also in the best period, during the 1990s, was probably greater than if the occupational noise exposure had not occurred. This study made clear the need for a valid reference data base, representing the statistical distribution of hearing threshold levels in a population not exposed to occupational noise but otherwise comparable to the group under study. In the second part of the dissertation, reference data for hearing threshold levels in women and men aged from 20 to 79 years are presented, based on measurements of 603 randomly selected individuals in Östergötland. A mathematical model is introduced, based on the hyperbolic tangent function, describing the hearing threshold levels as functions of age. The results show an age-related gender difference, with poorer hearing for men in age groups above 50 years. The prevalence of different degree of hearing loss and tinnitus is described for the same population in the third part of the dissertation. The overall prevalence of mild, moderate, severe or profound hearing loss was 20.9% collectively for women and 25.0% collectively for men. Tinnitus was reported by 8.9% of the women and 17.6% of the men. Approximately 2.4% of the subjects under study had been provided with hearing aids. However, about 7.7% were estimated to potentially benefit from hearing aids as estimated from their degree of hearing loss. Noise-induced hearing loss primarily causes damage to the outer hair cells of the inner ear. The fourth and last part of the dissertation evaluates the outer hair cell function, using otoacoustic emission measurements (OAE). Prevalence results from three different measuring techniques are presented: spontaneous otoacoustic emissions (SOAE), transient evoked otoacoustic emissions (TEOAE) and distortion product otoacoustic emissions (DPOAE). Gender and age effects on the recorded emission levels were also investigated. Women showed higher emission levels compared to men and for both women and men the emission levels decreased with increasing age. The results from the OAE recordings were shown to be somewhat affected by the state of the middle ear. The study included tympanometry, and the relation of the outcome ofthis test to the otoacoustic emissions is described, where high middle ear compliance resulted in low emission level. Reference data for the tympanometric measurements are also presented. The results of this project form an essential part of the important work against noiseinduced hearing loss, which needs continuous monitoring. The reference data presented here will provide a valid and reliable data base for the future assessment of hearing tests performed by occupational health centres in Sweden. This data base will in turn prove useful for comparison studies for Sweden as a responsible fellow EU member country setting high standards for work force safety. The statistical distribution of hearing threshold levels as a function of age for men and women in tabulated form is available on the Swedish Work Environment Authority (Arbetsmiljöverket) web site: http://www.av.se/publikationer/bocker/fysiskt/h293.shtm.

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Carbonate platforms contain a wealth of information regarding the changing biota, sea level, ocean-chemistry, and climate of the Cretaceous Period. The Comanche platform of the northern Gulf of Mexico represents a vast, long-lived carbonate system that extended from west Texas through the Florida panhandle. In central and south Texas, excellent outcrops and an extensive suite of subsurface data provide an opportunity to document the evolution of this system, from the shoreline to the shelf-margin and slope. This study examines the changing facies, platform morphologies, and shelf-margin architectures of the mixed carbonate-siliciclastic, middle-Hauterivian to lower-Campanian interval. Stratigraphic results are integrated with stable-isotope geochemistry to document the detrimental effects of oceanic anoxic events on the carbonate platform. Seven second-order, transgressive-regressive supersequences of 3-14 Myr duration are defined in south Texas using sequence stratigraphic analysis of shelf-interior facies successions. Second-order supersequences are subdivided into several third-order depositional sequences of 1-3 Myr duration. In these sequences, facies proportions and stratal geometries of the shelf-interior are found to be the result of changing platform morphology and temporal evolution from distally-steepened ramp to rimmed-shelf depositional profiles. Shelf-margin trajectories, stratigraphic architectures, and facies proportions are a function of long-term accommodation trends expressed in second-order supersequences. These characteristics are modified by lateral variability in the underlying structural/tectonic setting and localized syndepositional faulting. The stratigraphic equivalents of oceanic anoxic events 1a, 1b, 1d, 2, and 3 are documented in the Cretaceous section of south Texas. These oceanic anoxic events coincided with maximum flooding zones of supersequences and are linked to carbonate platform drowning events on four separate occasions. The occurrence of oceanic anoxic events is found to be a fundamental driver of carbonate platform morphology, faunal composition, and facies evolution in transgressive-regressive supersequences of the northern Gulf of Mexico. / text

ENGLISH SUMMARY Ammonite assemblage from the Upper Cenomanian of the Bohemian Cretaceous Basin realtively poorly known. Some species have been described herein for the first time: Thomelites cf. sornayi (Thomel) Euomphaloceras septemseriatum (Cragin) Eucalycoceras pentagonum (Gragin) and Allocrioceras annulatum (Shumard.). These records predominantly come from the M. geslinianum zone sediments developed in the higher parts of the Pecinov member (Uličný et al., 1998) of the Peruc - Korycany Formation. The sediments yielding ammonite assemblage represents the Late Cenomanian transgressive tract, accompanied by anoxic event OAE II = Oceanic anoxic Event II, CTBE) worldwide recorded in sediments and showing an increased content of stable isotope δ13 C. The OAE II is suggested to be connected to marine biota crisis and also the mass extinctionas well. The most affected organisms were benthic forms, due to high anoxic conditions at the bottom of the water column. Morphological features of the shells may, depending on the quality preservation shells (or cores) can be used to paleobathymetric interpretations. Most described species lived at depths of 50-80 m (up to 100m). Pelagic ammonites (i.e. Sciponoceras) lived at depths of up to 50 m. Heteromorphic taxa (Allocrioceras) have occurred at a depth of up to 100 m.