Dissertations / Theses on the topic 'OAE3'

Il Cretacico si caratterizza per la presenza di diversi intervalli di alterazione del sistema climatico-oceanico a scala globale responsabili della deposizione di black-shale marini ricchi di carbonio, definiti come Eventi Anossici Oceanici (OAEs). L’OAE3 rappresenta l’ultimo episodio di diffusa anossia durante l’intervallo Coniaciano-Santoniano. Rispetto ai precedenti eventi anossici, l’OAE3 ha una estensione regionale, ma non globale, poiché risulta essere confinato all’Oceano Atlantico sud-equatoriale e ad alcuni bacini limitrofi (es: Bacino Caraibico, Bacino del Western Interior). Altre importanti differenze fra l’OAE3 e i precedenti eventi anossici consistono nell’assenza di una anomalia del δ13C, ma piuttosto il verificarsi durante il Coniaciano-Santoniano di una serie di escursioni isotopiche sia positive che negative di piccola entità. Inoltre la deposizione di sedimenti ricchi di materia organica (black shales) sembra essere diacrona anche all’interno dello stesso Atlantico centro-meridionale. I principali obiettivi di questa tesi sono la ricostruzione di eventuali cambiamenti paleoceanografici avvenuti durante l’OAE3 in base alle variazioni di abbondanza e composizione delle associazioni a nannofossili calcarei. Il mio progetto di dottorato si è concentrato sulla biostratigrafia e paleoceanografia a nannofossili calcarei per l’intervallo compreso tra il tardo Turoniano e il Campaniano inferiore (Cretacico Superiore) e in particolare sul Coniaciano-Santoniano. La studio delle associazioni a nannofossili calcarei sia in termini semiquantitativi che quantitativi ha permesso di ottenere una biostratigrafia di dettaglio utile a datare e correlare le variazioni del nannoplancton calcareo durante l’OAE3. Lo studio è stato condotto sia su siti oceanici carotati nell’ambito dei progetti Deep Sea Drilling Project (DSDP) e Ocean Drilling Program (ODP) che su sezioni continentali, situate nell’Atlantico sud-equatoriale, in Oceano Indiano e nel Bacino Anglo-Parigino. I risultati ottenuti sono stati poi integrati con dati di letteratura al fine di ottenere una successione di eventi per il Coniaciano-Santoniano e fornire una caratterizzazione paleoceanografica dell’OAE3. È stata realizzata una dettagliata revisione tassonomica per risolvere alcune incongruenze tassonomiche e ottenere una terminologia aggiornata e unificata. Questa è stata la base per una biostratigrafia coerente, ad alta risoluzione delle successioni studiate, e stabilire una datazione e correlazione a scala sovra-regionale. Sono state applicate le quattro biozonazioni standard proposte per il Cretacico Superiore per ottenere la massima risoluzione e testare la loro applicabilità nei diversi bacini e contesti oceanografici. Le analisi quantitative delle associazioni a nannofossili calcarei hanno permesso di caratterizzare la distribuzione dei nutrienti prima, durante e dopo l’OAE3. La distribuzione dei taxa indicativi di più alta fertilità mostra caratteristiche diverse per le varie successioni, suggerendo che l’OAE3 non è stato caratterizzato da un episodio globale di fertilizzazione. Infatti, la fertilità rimane in genere bassa ad eccezione delle aree di upwelling che sono caratterizzate da condizioni meso-eutrofiche anche negli intervalli che precedono e seguono l’OAE3. Le analisi quantitative condotte in questo studio hanno evidenziato la presenza di ampie fluttuazioni di abbondanza dei generi Micula e Marthasterites durante il Coniaciano-Santoniano. Questi picchi di abbondanza possono essere correlati con eventi analoghi descritti in letteratura, anche se con valori di incremento differenti nei vari siti. Durante l’OAE3 sono stati individuati due distinti picchi di abbondanza di Marthasterites (M. furcatus) e cinque di Micula (M. staurophora). L’affinità paleoecologica di Micula, e in particolare M. staurophora, così come quella del genere Marthasterites rimane poco chiara, pertanto le cause dei loro picchi di abbondanza devono essere individuate. Tuttavia, le fluttuazioni nelle associazioni a nannofossili calcarei indicano un profondo cambiamento paleoceanografico durante il Coniaciano-Santoniano. L’inizio dell’OAE3 coincide con un elevato aumento in abbondanza (e localmente dominanza) di M. furcatus, che suggerisce il rapido instaurarsi di nuove e peculiari condizioni paleoceanografiche ad ampia scala. Le condizioni paleoceanografiche più alterate sono raggiunte nella parte centrale dell’OAE3 con un picco di abbondanza (climax) di M. staurophora sincrono a scala globale. Oltre al loro valore per le ricostruzioni paleoambientali, i picchi di abbondanza di Micula and Marthasterites si sono rilevati estremamente utili per complementare/implementare la caratterizzazione biostratigrafica dei limiti Turoniano/Coniaciano, Coniaciano/Santoniano e Santoniano/Campaniano. Questi picchi di abbondanza potrebbero dunque essere introdotti come eventi addizionali in future zonazioni a nannofossili calcarei del Cretacico Superiore.
The Late Cretaceous was punctuated by several periods of global perturbations of the climate-ocean system that lead to widespread organic carbon-rich marine black shale deposition, termed Oceanic Anoxic Events (OAEs). The OAE3 represents the last episode of anoxia dated as Coniacian-Santonian. Compared to previous anoxic events, OAE3 has a regional extension, rather than a global significance, since it is confined to the equatorial-south Atlantic Ocean and adjacent basins (e.g. Caribbean Basin, Western Interior Basin). Another major difference of OAE3 relative to previous OAEs resides in the absence of a prominent δ13C anomaly, but the occurrence of several minor positive and negative excursions in the Coniacian-Santonian interval. Moreover, the deposition of organic carbon-rich sediments (black shales) seems to be diachronous even in the central-south Atlantic Ocean. This PhD project focused on calcareous nannofossil biostratigraphy and paleoceanography of the Late Turonian to Early Campanian time interval (Late Cretaceous), and specifically of the Coniacian-Santonian. Nannofossil assemblages were investigated semiquantitatively and quantitatively to obtain a detailed biostratigraphic framework for assessing the paleoenvironmental changes across OAE3. The study was performed on Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP) sites and on-land sections, situated in the equatorial and south Atlantic Ocean, the Indian Ocean and the Anglo-Paris Basin. The results of my investigation were integrated with data from literature in order to achieve a solid framework of events for the Coniacian-Santonian time interval and provide a paleoceanographic characterization of OAE3. A detailed revision of the taxonomy was accomplished for solving a few taxonomic incongruities and obtain a unified updated nomenclature. This was the basis for the coherent high-resolution biostratigraphy of the selected sites, in order to establish dating and correlations at supra-regional scale. The four standards biozonation schemes available for the Upper Cretaceous were applied to attain the maximum resolution and test their individual applicability in different oceanic basins and oceanographic settings. The major objective of this PhD thesis was the reconstruction of presumed paleoceanographic changes across OAE3 as recorded by abundance and composition of calcareous nannofossil assemblages. Quantitative analyses of calcareous nannofossil assemblages allowed the characterization of paleotemperature and nutrient changes prior, during and after OAE3. Nannofossil-based paleotemperature obtained in this study and documented in the literature do not show significant changes in the studied successions, perhaps due to unresolved unambiguous temperature-related taxa in the Late Cretaceous and/or minor (subtle) temperature changes across OAE3. As far as paleofertility isconcerned, the nannofossil taxa indicative of higher nutrient content display very different patterns at the various sites, suggesting that OAE3 was not characterized by a global fertilization episode. Indeed, fertility remained globally low with the exception of upwelling areas characterized by meso-eutrophic conditions also in the intervals preceding and following OAE3. The quantitative analyses conducted in this study pointed out relatively large fluctuations in abundance of genera Micula and Marthasterites in the Coniacian-Santonian interval. These abundance peaks could be correlated with analogous events described in the literature, even if with different values of abundance at the various sites/sections. Two Marthasterites (M. furcatus) abundance peaks and five Micula (M. staurophora) abundance peaks were distinguished across OAE3. The paleoecological affinity of Micula, and specifically M. staurophora, as well as that of genus Marthasterites remains unexplained, so the causes of their abundance peaks continue to be elusive. However, the distinctive fluctuations in nannofossil assemblages indicate profound paleoceanographic changes during the Coniacian-Santonian. The onset of OAE3 coincides with a major increase in abundance (and locally dominance) of M. furcatus suggesting the rapid establishment of new and peculiar paleoceanographic conditions at widespread to global scale. The most altered paleoceanographic conditions were reached in the core of OAE3 with the synchronous maximum abundance (climax) of M. staurophora at global scale. In addition to their value for paleoenvironmental reconstructions, the identified Micula and Marthasterites abundance peaks turned out to be extremely useful for complementing/implementing the biostratigraphic characterization of the Turonian/Coniacian, Coniacian/Santonian and Santonian/Campanian boundaries and might be introduced as additional events in future nannofossil zonations for the Late Cretaceous.

Tese (doutorado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Civil e Ambiental, 2017.
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São apresentados os resultados de uma pesquisa que teve como objetivo propor um modelo de previsão da degradação, baseada numa análise determinística e estocástica, para contribuir no acompanhamento das Obras de Arte Especiais – OAEs do Brasil, sob responsabilidade do Departamento Nacional de Infraestrutura de Transporte – DNIT, e para banco de dados similares. No banco de dados do DNIT consta o inventário de quatro mil quinhentos e trinta e uma OAEs, com uma vistoria realizada entre 2012 a 2016 para todas as obras do inventario. Devido ao número insuficiente de registros históricos para o desenvolvimento de um modelo de previsão da degradação das OAEs, foram testados os modelos de degradação utilizando-se o banco de dados do Departamento de Transporte de Nevada (NDOT), obtido durante um ano de estágio desenvolvido na Universidade de Nevada, Las Vegas (USA). Foi realizado um estudo comparativo dos modelos de degradação, e após a calibragem dos modelos de previsão com o banco de dados de NDOT, foi determinado o modelo de degradação mais apropriado para as OAEs sob responsabilidade do DNIT e banco de dados similares, visando proporcionar apoio na tomada de decisões e garantir um desempenho eficiente das estruturas. Foi determinado que a Regressão de Potência é o método de cálculo mais apropriado para a estimação das curvas de degradação das OAEs no Brasil, sob responsabilidade do DNIT. Podendo-se utilizar esta regressão de maneira individual para cada uma das OAEs, uma vez sejam realizadas mais inspeções nas estruturas.
The objective of this research was to propose a degradation prediction model, based on a deterministic and stochastic analysis, to contribute to the accompaniment of the Brazil Bridges, under the responsibility of the National Department of Transport Infrastructure - DNIT, and other similar databases. In the DNIT database there is an inventory of four thousand five hundred and thirty-one bridges, but only one inspection was carried out between 2012 and 2016. Due to the insufficient number of historical records for the development of a model for predicting the degradation of bridges, the models of degradation were tested using the database of the Department of Transportation of Nevada (NDOT), obtained during a year of internship developed at the University of Nevada, Las Vegas (USA). A comparative study of the degradation models was carried out, and after the calibration of the forecast models with the NDOT database, the most appropriate degradation model was determined for the bridges under the responsibility of DNIT and similar databases, aiming to provide support in decision-making and ensure efficient performance of structures. It was determined that the Power Regression is the most appropriate calculation method for the estimation of the degradation curves of OAEs in Brazil, under the responsibility of DNIT. This regression can be used individually for each of the OAEs, once more inspections are performed on the structures.

Chez l'Homme, l'infection par le virus chikungunya (CHIK), un membre du genre Alphavirus de la famille des Togaviridae, se manifeste classiquement par des arthralgies aiguës. La flambée inattendue de fièvre chikungunya dans les îles de l'Océan Indien en 2006 mis en exergue la nécessité de comprendre la pathogénie de cette maladie peu étudiée. La caractérisation moléculaire de plusieurs isolats cliniques collectés sur l'Ile de La Réunion mis en évidence l'émergence du variant viral E1-226V associé à l'adaptation au vecteur Ae. Albopictus. Pour poursuivre cette caractérisation, nous avons produit des outils spécifiques pour la détection du virus CHIK comme une forme soluble de la glycoprotéine d'enveloppe E2 (gp-E2) ainsi que des anticorps monoclonaux murins spécifiques de la gp-E2 du virus. Chez les individus infectés par les alphavirus dont le virus CHIK, l'infection virale est contrôlée par l'IFN-α/β. Qui stimule la production d'un ensemble de molécules antivirales. Nos travaux suggèrent qu'une famille de ces gènes, les 2',5'-Oligoadenylate Synthétases (OAS), joue un rôle primordial dans l'immunité innée anti-arbovirale. Nous avons étudié si l'isoforme OAS3 humaine joue un rôle contre l'infection par le virus CHIK. Les cellules épithéliales humaines surexprimant l'OASS inhibent efficacement la croissance du virus CHIK aussi bien que d'autres alphavirus comme les virus Sindbis et Semliki Forest. Cette activité anti-alphavirale empêche l'accumulation des ARN viraux et des protéines virales. En conclusion, l'activité de la protéine OAS3 représente une importante voie anti-alphavirale par laquelle l'IFN-α/β contrôle l'infection du virus CHIK dans les cellules humaines
Humans infected with chikungunya virus (CHIKV), a member of the Alphavirus genus of the Togaviridae family, typically experience acute illness with incapaciting polyarthralgia. The unexpected outbreak of chikungunya fever in the Indian Ocean islands in 2006 highlights the need to understand this disease pathogenesis not well studied. Several clinical isolates collected in La Reunion Island were characterized at the molecular level. Our study emphasized the emergence of the viral variant E1-226V associated with adaptation to the vector Ae. Albopictus. The production of specific tools for the CHIK virus detection was necessary to pursue this characterization. We produced a soluble form of the envelope E2 glycoprotein (gp-E2) in Drosophila S2 cells, as well as mouse monoclonal antibodies specific of the virus gp-E2. In people infected by alphavirus such as CHIK virus, the viral infection is controlled by IFN-α/βwhich stimulates the production of a set of antiviral molecules. Our laboratory had shown that the 2', 5'-Oligoadenylate Synthetases (OAS) genes, inducible by IFN-α, play a critical role in antiviral immunity against arboviruses. Whether the OAS3 human form may play a role in the protective innate immunity to CHIKV was investigated. Human epithelial cells respond to ectopic OAS3 protein expression by inhibiting CHIKV growth as efficiently as that of other alphaviruses such as Sindbis and Semliki Forest viruses. The OAS-mediated inhibition of CHIKV growth was attributable to a dramatic reduction in viral RNA and protein levels. In conclusion, OAS3 activity represents an important antialphaviral pathway by which IFN-α/β controls CHIKV infection in human cells

La Chondrodonta, un bivalve simil-ostreide e opportunista, è comunemente riportata nelle piattaforme carbonatiche Tetidee del Cretaceo, con una particolare concentrazione nel periodo Aptiano – Cenomaniano. Nonostante ciò, non è ancora emersa una chiara relazione né temporale né causale tra la proliferazione di questo bivalve e gli Eventi Anossici Oceanici (OAEs). Per tali ragioni, la distribuzione stratigrafica e il significato paleoecologico della Chondrodonta sono stati analizzati ai fini di stabilire un preciso rapporto temporale tra i suoi accumuli e gli OAEs e di definire le possibili perturbazioni ambientali alla base della sua proliferazione. Gli accumuli di Chondrodonta analizzati affiorano nelle successioni carbonatiche di piattaforma interna della Piattaforma Apula (Aptiano inferiore, a ridosso dell’OAE1a), e della Piattaforma Adriatica (Cenomaniano superiore, a ridosso dell’OAE2). Il contesto stratigrafico intorno agli accumuli è stato ricostruito attraverso analisi bio- e chemostratigrafiche. Analisi sedimentologico-litostratigrafiche e geochimiche (concentrazione di elementi maggiori, in traccia e di Terre Rare) hanno permesso di dedurre le variazioni paleo-ambientali associate alla proliferazione del bivalve. Sulla base della correlazione dei record isotopici tra piattaforma e bacino, si è osservato come gli accumuli di Chondrodonta ricadano al di sotto delle tipiche escursioni nella curva del δ13C che segnano, rispettivamente, l’inizio dell’OAE1a e dell’OAE2. In entrambe le successioni studiate, la Chondrodonta appare subordinata all’interno dei calcari a rudiste e raggiunge una fase di massima proliferazione e predominanza sulle stesse rudiste in prossimità dell’inizio degli eventi anossici. Dalle analisi stratigrafiche e geochimiche è emerso come gli intervalli di proliferazione di Chondrodonta siano caratterizzati da un aumento di nutrienti oltre la soglia di tollerabilità per le rudiste, e da fluttuazioni nell’ossigenazione e nell’apporto terrigeno in acque di bassa energia. Gli intervalli a Chondrodonta sono stati correlati anche ad una crescente fertilità e ad un progressivo deterioramento ambientale nelle vicine aree bacinali. La posizione stratigrafica degli accumuli globali di Chondrodonta precede l’inizio degli OAE1a e 2 in piattaforme carbonatiche poste a differenti latitudini e condizioni climatiche, permettendo di considerare la proliferazione di questo bivalve come un bioevento a scala regionale. La proliferazione di Chondrodonta risulta quindi inseribile all’interno di una “finestra ambientale”, innescata dai cambiamenti climatici che preludono gli OAEs e principalmente caratterizzata da un aumento di nutrienti sulle piattaforme carbonatiche. Il bivalve opportunista Chondrodonta beneficia, infatti, della transizione da condizioni oligotrofiche a mesotrofiche in piattaforma, occupando una nicchia ecologica posta al passaggio tra comunità stenotopiche ed euritopiche. La presenza e la durata della “finestra ambientale” sono controllate anche da condizioni paleo-geografiche e idrodinamiche locali così come da locali fluttuazioni nell’ossigenazione delle acque e negli apporti terrigeni. L’eccessivo deterioramento delle condizioni ambientali all’inizio degli OAEs inibisce, per contro, la proliferazione della Chondrodonta provocando la sua scomparsa dalla comunità bentonica in favore di specie propriamente mesotrofiche come dimostrato per la Chondrodonta dell’Aptiano inferiore all’inizio dell’OAE1a. La proliferazione della Chondrodonta rappresenta, quindi, un marker stratigrafico a scala regionale del crescente stress ambientale in piattaforma. La predominanza transitoria della Chondrodonta all’interno della comunità bentonica costituisce la risposta biologica dei sistemi carbonatici di acque basse al crescente deterioramento ambientale che culmina con gli Eventi Anossici Oceanici 1a e 2 del Cretaceo.
The opportunistic, oyster-like bivalve Chondrodonta, common in Tethyan Cretaceous shallow-water carbonates, shows peaks of concentration during the Aptian – Cenomanian time interval. Despite this, neither a temporal nor a causal relationship between the flourishing of this bivalve and Oceanic Anoxic Events (OAEs) has emerged yet. The stratigraphic distribution and the ecological significance of Chondrodonta have been analyzed to both define the timing between its accumulations and OAEs and infer OAE-related environmental perturbations triggering its proliferation. The studied Chondrodonta accumulations occur in inner platform limestones of the lower Aptian Apulia Carbonate Platform straddling OAE1a, and of the upper Cenomanian Adriatic Carbonate Platform straddling OAE2. The stratigraphic framework around the Chondrodonta beds has been built using biostratigraphic and chemostratigraphic data. Palaeoenvironmental changes associated with its proliferation have been inferred by coupling sedimentologic-lithostratigraphic analyses with the concentration of major, trace elements and REE. Based on platform-to-basin stratigraphic correlations, the lower Aptian Chondrodonta beds occur right below the negative δ13C excursion marking the onset of OAE1a and the upper Cenomanian beds occur below the δ13C positive excursion of the OAE2 interval. In both cases, Chondrodonta appears in the stratigraphic succession associated with rudist limestones and then reaches a phase of maximum proliferation and predominance over rudists at the prelude of OAEs. As emerged by stratigraphic and geochemical analyses, the Chondrodonta proliferation occurred in an interval of increasing nutrients and in low-energy seawaters with fluctuating oxygenation and intermittent terrigenous inputs. These environmental changes prevented the settlement of the less tolerant rudists while they promoted the thriving of Chondrodonta in monospecific (or quasi-) benthic communities close to the onset of OAEs. The intervals of Chondrodonta proliferation also correlate to increasing fertility and environmental deterioration in the nearby basins. Further, the stratigraphic position of lower Aptian and upper Cenomanian Chondrodonta accumulations in worldwide carbonate platforms located at different palaeolatitudes and climates, generally predates the onset of OAEs and enables to consider the proliferation of this bivalve as a regional bioevent. Accordingly, the flourishing of Chondrodonta is ascribable within an environmental “window”, triggered by the changing climate preluding OAEs and mainly resulted in nutrient pulses on the platforms top. The opportunistic behavior of Chondrodonta was rather efficient in the transition from oligo- to mesotrophic conditions in shallow-water carbonate areas. This oyster-like bivalve benefitted from this environmental instability and occupied a short-lived environmental niche between more stable, stenotopic and eurytopic benthic communities. The occurrence and duration of this environmental “window” were also controlled by local, quick fluctuations in other seawater parameters (e.g., oxygenation, terrigenous inputs) and by limiting environmental factors related to palaeogeography and hydrodynamics. However, further increase of inhospitable conditions leading to OAEs inhibited the proliferation of the bivalve, allowing fully mesotrophic taxa to dominate the benthic community. This is particularly demonstrated for the early Aptian Chondrodonta, abruptly outpaced by mesotrophic assemblages at the onset of OAE1a. The proliferation of Chondrodonta can be, therefore, used as a regional stratigraphic marker for an early phase of environmental stress in shallow-water carbonate platforms. Its transitionary predominance within the benthic community represents the biotic response of the Cretaceous shallow-water carbonate systems to increasing environmental deterioration peaking with Oceanic Anoxic Events 1a and 2.

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The sheep production has been growing surprinsingly in the last years in Brazil, but in despite of this, it can not be considered competitive yet, principally because the lack of structure and organization of the sector. Among the problems faced by the Brazilian sheep producers we could cite the gastrointestinal parasites and the relatively low productivity of the native breeds when compared with the exotic ones. The knowledge of the genetic factors controlling these traits can help in the improvement of then without impair the correlated traits. Through molecular biology and statistical technics is possible to identify genes/chromosomal regions associated with these traits and once the region is confirmed as really important in the control of the characteristic this information could be used in breeding programs through marker assisted selection. Many regions were identified as candidate for growth and nematode resistance traits in sheep and other ruminants, and among of them is the Q arm of the sheep chromosome OAR3. Because of this, the aim of this study was to investigate three microssatelite markers located in the Q arm of the OAR3 and its relationship with growth and nematode resistance traits in sheep from three genetic groups: Santa Inês X Santa Inês, Dorper X Santa Inês e Suffolk X Santa Inês. The association analysis revealed two alleles of the BL4 marker with significative effect in the Santa Inês x Santa Inês genetic group and one allele form the same marker with significative effect in the genetic group Dorper x Santa Inês on birth weight. It was also observed one allele from the BL4 marker associated with slaughter weight in the Santa Inês x Santa Inês genetic group. We did not observe any association between the markers studied and nematode resistance. Our results suggest that there are one or more genes in the studied region related with growth traits, but more studies are required to confirm the importance of this region in the control of these traits and to identificate the candidate genes.
A ovinocultura, apesar de apresentar um crescimento significativo nos últimos anos, ainda não pode ser considerada no Brasil como uma exploração competitiva. Isto se deve principalmente pela falta de organização e estruturação do setor produtivo. Dentre os problemas da ovinocultura nacional podemos citar as parasitoses gastrintestinais e a baixa produtividade das raças locais quando comparadas com raças importadas. O entendimento dos fatores genéticos que controlam as características produtivas pode auxiliar na melhoria dos rebanhos para uma característica importante sem significar prejuízo a outras características. Através de técnicas de biologia molecular e estatística pode-se identificar genes/regiões cromossômicas responsáveis pelo controle dessas características e uma vez que essas regiões sejam identificadas e comprovadas como importantes, essa informação pode ser utilizada em programas de melhoramento genético através de seleção assistida por marcadores. Algumas regiões já foram identificadas como sendo candidatas a conter genes importantes tanto para resistência aos nematódeos gastrintestinais quanto para características de crescimento em ovinos e outras espécies de ruminantes. Dentre estas regiões está o braço Q do cromossomo OAR3 dos ovinos. Por isso, o objetivo deste trabalho foi estudar três marcadores microssatélites localizados no braço Q do cromossomo ovino OAR3 e suas relações com as características de crescimento (peso ao nascimento e peso ao abate) e resistência aos nematódeos gastrintestinais utilizando ovinos pertencentes a três grupos genéticos (Santa Inês X Santa Inês, Dorper X Santa Inês e Suffolk X Santa Inês). A análise de associação revelou a presença de dois alelos do marcador BL4 com efeito significativo no grupo genético Santa Inês x Santa Inês e um alelo do mesmo marcador com efeito significativo no grupo genético Dorper x Santa Inês para peso ao nascimento. Também foi observado efeito de um alelo do marcador BL4 com efeito significativo no grupo genético Santa Inês x Santa Inês para peso ao abate. Não foi observado efeito significativo de nenhum marcador na característica de resistência aos nematódeos gastrintestinais. Os resultados deste trabalho sugerem a presença de um ou mais genes na região estudada para características de crescimento, porém mais estudos são necessários para confirmar a real importância desta região no controle destas características bem como a identificação de possíveis genes candidatos.

Rapid changes in Earth?s marine environment are sufficiently rare that the scope and consequences of these events cannot be inventoried without recourse to the stratigraphic record of deep pre-historic time. Traditional stratigraphy divides geologic time into a succession of coarse biozones ? uneven time bins, each recognized by distinctive index fossils and spanning several hundred thousand to even a few million years. This thesis uses the CONOP software to resolve sequences of global appearance and disappearance events at the species level across the late Cenomanian oceanic anoxic event (OAE 2) at a much finer resolution than traditional biostratigraphy. The resulting time-lines include information for the Aptian to Maastrichtian from 501 locations, 4,962 taxa, and 25,112 local last occurrences. This dataset is large enough to represent the global environment and to compensate for the inevitably patchy and incomplete record preserved at any one location. Six geographically widespread clades ? ammonites, calcareous nannofossils, dinocysts, benthic forams, planktonic forams, and radiolaria ? were analyzed; they span a range of trophic levels, composition and preferred habitat. Extinction pulses and intervals of falling diversity are not unique to OAE 2 or even uniquely severe. Several occur throughout the Albian-Santonian interval. The key is to monitor trends in diversification rate. OAE 2 is distinguished as a boundary between more positive (or equal in the ammonite case) and more negative diversification regimes. It may have been part of a general habitat deterioration or disturbance, but it would be too simplistic to describe it as a coordinated pelagic extinction event.

Oceanic anoxic events occur in response to significant climate perturbations. This study focuses on the late Cretaceous OAE 2, which occurred across the Cenomanian-Turonian boundary (CTB), ~93.9 Ma. Multiple isotope proxies have reviewed the implications of palaeocirculation, volcanism and climate change to assess the driving mechanism(s) associated with global anoxia. Utilising geochemistry and geochronology (Os, Ca and U-Pb) this study provides a greater understanding of palaeoclimate conditions and assesses the global extent of anoxia. Hitherto, analyses have focussed on sections in and around the proto-North Atlantic. Herein, high-resolution 187Os/188Os isotope stratigraphy from 8 globally representative sections is presented; Portland #1 core, Site 1260, Wunstorf, Vocontian Basin, Furlo, Site 530, Yezo Group, and Great Valley Sequence. The Re-Os system is sensitive to regional and global variation in seawater chemistry on the order of the residence time of Os due to ocean inputs: radiogenic Os from continental weathering and unradiogenic Os from hydrothermal inputs. The initial 187Os/188Os (Osi) profiles present a globally ubiquitous trend: radiogenic Os values are attenuated by unradiogenic Os for ~200 kyr, which then gradually return to radiogenic Os. Minor discrepancies illustrate the sensitivity of local water masses as a function of basin connectivity and global sea level; i.e., Portland, Great Valley Sequence and Yezo Group (temporally restricted basins) vs. Site 1260 and Site 530 (open ocean). Furthermore, a temporal framework is developed from existing ages (from the Western Interior, USA) and new U-Pb zircon geochronology (Yezo Group, Japan) to quantify the duration of OAE 2 and volcanic activity at the Caribbean LIP. Age models are applied and support the revision of the stratigraphic position of the OAE 2 onset and the CTB in the Yezo Group. The integration of the Western Interior and Pacific geochronology quantitatively verifies that the OAE 2 was globally synchronous occurring at ~94.4 Ma ± 0.15 Ma. In addition, marine δ44Ca records from 4 global OAE 2 sections are presented. The seawater mixing models reveal that δ44Ca values show no appreciable change to riverine or hydrothermal influx. Herein, I quantitatively demonstrate that fractionation is a parameter for δ44Ca isotopic variation at Portland and Pont d’Issole, which may be attributed to diagenetic reactions in the marl-rich lithology leading to site-specific fractionation. Therefore, marine δ44Ca profiles are different in each section as a function of varying fractionation factor. Ca isotope systematics are highly complex and so further work is crucial in order to develop our understanding of other parameters and to establish which, if any, is the most influential.

The discovery of otoacoustic emissions (OAE) has advanced our understanding of cochlear mechanics and the efferent auditory system. OAE are sounds generated within normal cochlea either spontaneously or in response to stimulation. The ability to measure OAE non-invasively, objectively and quickly makes a powerful tool to probe cochlear mechanics. Stimulation of the efferent auditory system causes changes in cochlear amplification processes and hence changes characteristics of OAE. Contralateral acoustic stimulation, commonly called OAE suppression, provides an index of the efferent auditory system (specifically, medial olivocochlear bundle) functioning. OAE is also a sensitive tool to demonstrate subtle changes in cochlear functioning caused by various pathological (e.g., noise exposure, aspirin toxicity, etc.) and non-pathological (e.g.,posture, efferent stimulation) factors. Although OAE are frequently used in both clinic and laboratory, their generation mechanism was not clearly understood until recently. It is currently accepted that distortion product otoacoustic emissions (DPOAE) are composed of two separate components, named wave- and place-fixed emissions. They not only arise from two different cochlear locations but also from two fundamentally different processes. Wave-fixed components arise from distortion sources and manifest a phase that is almost independent of frequency, where as, place-fixed components arise from reflection sources and have a phase that increases systematically with frequency. The overall aim of the work presented in this thesis was to use various OAE methods to examine cochlear function and the efferent auditory system. A related objective was to substantiate the functional relevance of the efferent auditory system in speech-in-noise perception, in order to address the clinical significance of measuring OAE suppression. Cochlear functioning was potentially manipulated by three treatments separately: one extrinsic (electromagnetic radiation exposure from mobile phone) and two intrinsic (posture and efferent activation). Potential changes in auditory function due to mobile phone exposure were evaluated in a within-subject study in a double-blind design (n=35).A comprehensive examination of the auditory system was conducted using audiometry,OAE and auditory event related potentials (ERP). The second experiment used mechanism-based DPOAE to investigate posture-induced changes in cochlear functioning (n=15). Similar DPOAE measurements were performed to evaluate the effect of contralateral acoustic stimulation on cochlear functioning (n=14). The last experiment examined the relationship between contralateral suppression of transient evoked otoacoustic emissions (TEOAE) and recognition of speech in noise (n=13). Results indicate that (i) acute exposure to mobile phone radiation does not cause any significant changes in auditory functions measured by TEOAE suppression, DPOAE or ERP (however, there were changes in auditory thresholds at 6 and 8 kHz), (ii) posture induced cochlear changes and contralateral acoustic stimulation cause significantly greater reduction in place-fixed components than wave-fixed components, and (iii) the efferent auditory system plays an anti-masking role in speech-in-noise recognition. It appears that wave- and place-fixed components are differentiallysensitive to changes in cochlear functioning. Collectively, the present results provide emerging empirical support for the need to separate the wave- and place-fixed components in DPOAE measurements. Because of inherent differences in the generation of wave- and place-fixed components, it is suggested that the separation of the components may improve the efficiency of DPOAE-based measures of cochlear dysfunction and also, of the efferent auditory system function.

Populationer med utvecklingsstörning behöver kontinuerlig hörseltestning, men konsensus om lämplig testmetod saknas. Syfte: Syftet med Studie I var att utvärdera psykoakustisk testmetod och med Studie II att utvärdera OAE-registrering som komplementär metod. Studie I. 1478 barn och vuxna med lätt till djup utvecklingsstörning, i åldrarna 7-91 år deltog i studien. De testades med tonaudiometri på sex frekvenser på screeningnivån 20 dB HL med lätt modifierad testutrustning. Kriterierna för remittering var tröskelnivåer på ≥ 25 dB HL på två frekvenser eller flera på ett öra eller båda. 1470 (99,5%) barn och vuxna medverkade i screeningen och 1325 (90%) testades på båda öronen på samtliga sex frekvenser. En majoritet, 987 (67,1%), medverkade i vanlig tonaudiometri, 234 (15,9%) i lekaudiometri, och 249 (16,9%) testades med observationsaudiometri. 669 (45%) visade normala värden medan 809 (55%) visade onormala värden relaterat till screeningkriterierna. Av de 809 accepterade 441 (54,5%) remittering för hörselutredning. Studie II. 38 vuxna med måttlig till djup utvecklingsstörning, i åldrarna 31-73 år deltog i studien, alla med ofullständiga testresultat vid tonaudiometri. Portabel utrustning, ILO 288 Echoport och dator Compaq LTE 5100 med mjukvara ILO 88 V 4.2, användes. Otoskopi och tympanometri kompletterade registreringen. Kriterierna för emissioner var S/N 3 dB eller mer och reproducerbarhet på 60% eller mer på åtminstone tre frekvensband. Kriterierna för partiella emissioner var desamma men för en eller två frekvenser. Två personer behövdes för att genomföra testningen: en för att hålla testpersonen lugn och tyst och den andra för att sköta testapparaturen. Reproducerbara TEOAE-svar registrerades från 11 öron (7 personer), partiella svar från 6 öron (4 personer), inga emissioner kunde registreras från 15 öron (10 personer) och 4 öron (4 personer) med otit eller vaxpropp testades inte. Registreringen från 24 öron (13 personer) kunde inte värderas p g a alltför mycket yttre och inre störningar. 8 personer vägrade delta i testningen. Endast 4 personer visade emissioner på båda öronen. Resultatet av undersökningen blev att 34 personer (89.5%) behövde testas om eller bli remitterade för ytterligare utredning, 21 av dem (55%) beroende på störningar vid registreringen eller p g a vägran att medverka. Konklusion: Tonaudiometri med lätt modifiering kan användas för screening av en population med lätt till djup utvecklingsstörning. TEOAE-registrering, som den genomfördes, kan inte uppfylla kraven på en fungerande testmetod för en population med måttlig till djup utvecklingsstörning. I det enskilda fallet kan TEOAE-registrering vara ett komplement till andra hörseltest. Det mest utmanande och tidskrävande är att introducera testprocedurerna på ett sätt som begränsar oro och skapar tillit. Oberoende av testmetod är en audionom med tålamod och vana att samarbeta med personer med utvecklingsstörning en viktig förutsättning för framgångsrik och säker testning.

Anthropogenic emissions of carbon dioxide into the atmosphere has indirectly driven acidification and reduced carbonate saturation of the oceans. Among calcareous plankton, coccolithophore algae are the major producers of pelagic CaCO3 in the modern ocean: they are direct contributors of the ocean biogeochemical cycles and climate system and, therefore, coccolithophore sensitivity to changes in surface water conditions is of major concern. Coccolithophores build around the cell an exoskeleton of calcite (coccosphere) that consists of single platelets called coccoliths and nannoliths. This phytoplanktonic group are affected by changes in surface water temperature, fertility, salinity, light and consequently are important instrument to A) predict the future state of the ocean, particularly its carbonate chemistry B) to reconstruct changes in past surface-water conditions. This PhD thesis is aimed to combine the geological and biological approaches, quantifying tempo and mode of coccolithophore response to specific combinations of stressing environmental conditions through investigation of a geological case history and laboratory experiments trying to simulate conditions of the past. During the Aptian Oceanic Anoxic Event 1a (OAE 1a) an extreme global perturbation of the atmosphere-ocean system was documented, with evidence of geologically rapid warming associated to ocean fertility and acidification at global scale. Erba et al. (2010) demonstrated that calcareous nannoplankton was extremely sensitive to ocean acidification during OAE 1a, allowing separation of most-, intermediate-, and least-tolerant taxa. After a major calcification failure of heavily calcified forms, ephemeral coccolith dwarfism and malformation represent the most remarkable species-specific adjustments to survive surface water acidity. The case history I focused on, is the latest Cenomanian Oceanic Anoxic Event 2 (OAE 2, ~ 94 Ma) which represents a profound perturbation of the ocean-atmosphere system caused by natural CO2 emissions related to the emplacement of the Caribbean Plateau causing climate change, ocean fertilization and acidification. The study was performed on pelagic sediments from five localities: Eastbourne (Sussex, United Kingdom), Clot de Chevalier (France), Novara di Sicilia (Sicily, Italy) and two Western Interior sections (Pueblo, Colorado and Cuba, Kansas, USA). These five sections have been chosen based on availability of integrated stratigraphy. In fact, they all have a good time control, especially C isotopic stratigraphy and biostratigraphy, that offers the opportunity to correlate data from the different localities, discriminating between local, regional and global changes. Moreover, the selected sections represent short and long-distance locations with respect to the Caribbean Plateau paleo-position. Morphometric analyses were performed on selected calcareous nannofossil taxa namely Biscutum constans, Zeugrhabdotus erectus, Discorhabdus rotatorius and Watznaueria barnesiae. During OAE 2 calcareous nannoplankton responded to variations in surface-water fertility, temperature and CO2-induced acidification with a calcification decline in the form of a general size reduction of coccoliths. Calcareous nannoplankton, also, was affected by dwarfism in a species-specific way: in all the five analyzed sections B. constans shows the amplest size fluctuations through the event. D. rotatorius shows a well express reduction in size while Z. erectus displays the minor size decrease. W. barnesiae doesn’t show significant changes in mean coccolith size or in morphology (e.g. ellipticity). Coccolith size fluctuations across OAE 2 are similar and synchronous in all the analyzed sections located at great distance in different oceans and settings. The nannofossil preservation was carefully assessed in order to avoid diagenetically altered material Accurate screening under light polarizing microscope ascertained that individual coccoliths considered for morphometry were complete, with a continuous outline and without evidence of crimping due to etching or overgrowth. At the OAE 2 onset an increase in coccolith size leads to maximum dimension around the first δ13C isotopic peak (peak A). Subsequently, B. constans, Z. erectus and D. rotatorius show a progressive decrease in the mean size, reaching the maximum reduction (dwarfism) at δ13C isotopic peak B. Smaller specimens are still present till the end of the event and only after δ13C isotopic peak C, in the upper part of the analyzed sections, a partial recovery in size is observed. High-resolution integrated stratigraphy allows to say that coccolith size fluctuations match paleoceanographic changes: • the first decrease in coccolith size is coeval with a CO2 pulse at the beginning of OAE 2; • the increase in coccolith size at δ13C isotopic peak A is well correlated with a significant CO2 drawdown and a discrete cooling episode. • the major decrease in coccolith size at δ13C isotopic peak B correlates with a strong metal peak along with a new increase in sea surface temperature. B. constans appears to be the most sensitive species to OAE 2 perturbations: the decrease in its coccolith size recorded in all the analyzed sections, is associated to some malformation (increased ellipticity). Calcareous nannofossil morphometric and morphological data obtained for the latest OAE 2 were compared with those available for the early Aptian OAE 1a data in order to derive similarities and differences. Such a comparison suggests that species-specific coccolith dwarfism was experienced during both OAE 1a and OAE 2. Such calcification change is associated to: - high pCO2 (> 900 ppm); - high temperature (ca. 35°C); - trace metal enrichment. Temperature and nutrient availability in surface waters do not seem to have been crucial for B. constans size, although warmer and more fertile oceans preconditioned the environmental perturbation. Available data, instead, suggest that ocean chemistry related to the amount of CO2 concentrations, played a central role in coccolith secretion by B. constans with a repetitive reduction in size during OAE 1a and OAE 2. Massive submarine volcanism of Ontong Java Plateau during OAE 1a and the Caribbean Plateau during OAE 2 triggered a disruption in the oceanic carbonate system: excess CO2 arguably induced ocean acidification associated that was detrimental to some marine calcifiers, with temporary failure of a few taxa and production of dwarf and malformed coccoliths in B. constans. Hydrothermal plumes during construction of large submarine plateaus introduced biolimiting metals that fertilized the global ocean. However, submarine hydrothermalism might have also pumped in some toxic metals that might have disturbed the functioning of some intolerant coccolithophorid species, thus affecting their biocalcification. Species-specific coccolith dwarfism seems to be the response of nannoplankton to ocean acidification during OAE 1a and OAE 2, and this resulted in a reduction in total calcification under high pCO2. Evidence of dwarfism and production of malformed coccoliths possibly represents species-specific adjustment to survive lower pH. Therefore, there is possibly a causal link between intervals of major submarine volcanism and changes in nannoplankton composition, abundance and biocalcification through OAE 1a and OAE 2. The second part of this thesis focuses on laboratory experiments of coccolithophores performed at the GEOMAR Helmholtz Centre for Ocean Research Kiel (Kiel, Germany). Only preliminary results are here presented. The starting point was the idea that changes in some environmental factors directly affect the physiology of coccolithophorid algae, thereby directly causing a change in coccolith mean size and weight. Environmental factors known to modify coccolith size and/or weight are salinity (Green et al., 1998; Bollmann and Herrle, 2007; Fielding et al., 2009), temperature (Watabe and Wilbur, 1966), nutrient availability (Batvik et al., 1997; Paasche, 1998), growth stage (Young and Westbroek, 1991), seasonality (Triantaphyllou et al., 2010) and carbonate chemistry (Riebesell et al., 2000, Iglesias-Rodriguez et al., 2008; Halloran et al., 2008; Beaufort et al., 2011; Bach et a., 2012). In this thesis I consider the potential role of some of these environmental factors - specifically salinity, carbonate chemistry, light intensities, trace metal enrichment and nutrient depleted conditions) as triggers of changes in coccolith size and/or weight. Five species were investigated (Emiliania huxleyi, Gephyrocapsa oceanica, Pleurochrysis carterae, Coccolithus pelagicus ssp. braarudii) in five different experiments. Similarly to fossils data, a species-specific response to the different treatments has been observed. E. huxleyi evidences an increase in the coccosphere diameter associated to an increase in coccolith volume under nutrient-starved conditions and specifically with low phosphate content. On the other hand, major decrease in coccolith volume has been observed for E. huxleyi only with the highest CO2 concentration (3000 ppm). However, with increased trace metal contents, a reduction in coccolith volume has been detected, too. G. oceanica appears to be very sensitive to carbonate chemistry variations and future more specific analyses should be done to figure out which parameter(s) of the carbonate system drive morphological modifications (e.g. carbon dioxide, bicarbonate, carbonate ion, protons). P. carterae instead shows very erratic patterns to the tested parameters. Furthermore, among experiments, different replicates resulted in different response suggesting unclear sensitivity to specific environmental conditions. Finally, Coccolithus pelagicus ssp. braarudii calcification appears to be beneficial under low-nutrient conditions and, specifically, in the phosphate-limited treatment. On the contrary, increased CO2 concentration appears to impart a negative feedback to coccolith volume, with an evident decrease hand in hand with increasing CO2 content. As mentioned above, further analyses are planned in the near future and particularly SEM investigation of coccolith morphology and morphometry to quantify changes in coccolith size and malformation. The results of my thesis emphasize that changes in environmental factors do affect coccolithophore growth: salinity, carbonate chemistry, nutrient content and trace metal can significantly impact coccolith calcification in present and past oceans. The OAE 2 paleoenvironmental perturbation indicates that there is a causal link between intervals of abnormal submarine volcanism and changes in nannoplankton biocalcification through OAE 2. Comparison with data available for OAE 1a and OAE 1d indicate that analogous causes (construction of large igneous provinces) have induced similar response at different times in the Cretaceous. Finally, the geological record indicates that at wide spatial scale calcareous nannoplankton can adapt to high pCO2, but past changes occurred over tens of thousands of years, giving time for life to adjust or even take advantage. Laboratory experiments on modern coccolithophore species (evolutionary-linked to Cretaceous taxa) remain the only means to assess if and which role environmental parameters have on quantity, type and amount of coccolith secretion. Although conscious of the very different time scales of processes and resolution, the double biological and geological approach to coccolithophore calcification is aimed at integrating the daily-decadal datasets with medium to long-term (thousands to millions of years in duration) data. This has the potential for achieving an improved understanding of coccolith biomineralization mechanisms and providing some guidance as to the response of biota to abrupt massive CO2 releases and how and at what rate pre-perturbation conditions are eventually restored.

Barn med Down syndrom har ofta återkommande hörselproblem som exempelvis vaxpropp och sekretorisk mediaotit. Vanligt förekommande hörselnedsättning bland dessa barn är en fluktuerande konduktiv hörselnedsättning. Den utvecklingsstörning som syndromet orsakar kan leda till att barnen ej kan medverka aktivt vid konventionella hörselmätningar. Metoder för hörselutredning av små barn och barn som ej kan medverka adekvat är BRA, OAE och tympanometri. Syftet med arbetet är att belysa resultaten från BRA, OAE och tympanometri hos barn med DS. Vidare syftar studien till att belysa tänkbara habiliterande insatser för att bibehålla eller förbättra hörseln hos barn med Down syndrom. Som metod används systematisk litteraturstudie. Resultatet från föreliggande studie visar att mätresultat skiljer sig mellan barn med Down syndrom och barn utan Down syndrom. Strukturella avvikelser i hörselsystemet hos barn med Down syndrom påverkar resultaten från dessa mätningar. Det är därför av vikt att resultaten tolkas utifrån kunskaper om hur olika faktorer i hörselsystemet orsakade av syndromet kan påverka resultaten. Barn med DS behöver regelbundna och återkommande hörselhabiliterande insatser för att förebygga konduktiva hörselnedsättningar.

Le passage Cénomanien-Turonien (~94 Ma) au Crétacé supérieur est marqué par une période de diminution de la quantité d’O2 dans les sédiments et la colonne d’eau et de perturbations biogéochimiques appelé Évènement Océanique Anoxique 2 (OAE 2). Comme l’ensemble des OAEs du Crétacé, l’OAE 2 s’est mis en place dans un contexte d’augmentation de la concentration en CO2 dans les océans et l’atmosphère, interprétée comme d’origine volcanique. L’hétérogénéité des réponses à cette perturbation globale suggère que des paramètres environnementaux régionaux ou locaux ont contribué au scénario de mise en place et d’évolution de l’OAE 2. L’objectif cette thèse est ainsi de déterminer le rôle de ces mécanismes à différentes échelles spatiales. La démarche consiste en une comparaison des conditions biogéochimiques associées à l’OAE 2 dans un bassin épicontinental, comme le Bassin Vocontien (SE France), avec les bassins océaniques mondiaux. La comparaison de données de géochimie organique (TOC, HI vs. OI), inorganique (enrichissements en éléments majeurs et traces, spéciation du fer) et isotopique (δ13C, δ15N, δ34S) de deux coupes du Bassin Vocontien semble indiquer que l’augmentation de la quantité de CO2 et de sulfates dans le bassin, associée à l’activité d’une Grande Province Volcanique, fut le facteur déclencheur de l’OAE 2. Par ailleurs, les hétérogénéités des conditions d’oxygénation semblent être majoritairement associées aux configurations géométriques des bassins et au taux de renouvellement des leurs eaux profondes, mais aussi aux conditions de productivité primaire influencés par les cycles de nutriments, et enfin aux paramètres climatiques régionaux
The Cenomanian-Turonian transition (~94 Ma) of the upper Cretaceous is marked by a period of decreased O2 concentration in the sediments and water-column and biogeochemical perturbations, named Oceanic Anoxic Event 2 (OAE 2). Like all the OAEs of the Cretaceous, OAE 2 was initiated in a context of increasing CO2 concentrations in the oceans and in the atmosphere, interpreted as volcanic outgassing. The heterogeneity in the responses toward this global-scale perturbation suggests that regional or local environmental mechanisms contributed to the scenario of initiation and evolution of OAE 2. The objective of this thesis is to determine the role of these mechanisms at different spatial scales. The approach consists in a comparison of the biogeochemical conditions associated with OAE 2 in an epicontinental basin, as the Vocontian Basin (SE France), with others basins in the world. The comparison of geochemical organic (TOC, HI vs. OI), inorganic (Major and Trace elements enrichments, iron speciation) and isotopic (δ13C, δ15N, δ34S) data of two sections from the Vocontian Basin likely indicate that the concentration of CO2 and sulfates in the basin, associated with the activity of a Large Igneous Province, was the triggering factor of the OAE 2. Heterogeneities in the oxygenation conditions were predominantly associated with basin configuration and renewal rate of deep waters, but also with primary productivity conditions and with regional climatic parameters

Otoacoustic Emissions (OAE) are minute acoustic responses originating from the cochlea as a result of an external acoustic stimulus and are recorded using a sensitive microphone placed in the ear canal. OAEs are acquired by synchronous stimulation with an acoustic click or tone burst and recording of the post-stimulus responses. This method of acquiring OAEs is known as transient evoked otoacoustic emissions (TEAOE) and is commonly used in clinics as a screening method for hearing and cochlear functionality in infants. Recently, a novel method of acquiring OAEs utilizing a swept-tone, or chirp, as a stimulus was developed. This method used a deconvolution process to compress the swept tone response into an impulse or click-like response. Because the human ear does not hear all frequencies (pitches) at equal loudness the swept-tone stimulus was equalized in amplitude with respect to frequency. This equalized stimulus will be perceived by the ear as equally loud in all frequencies. In this study a new hearing level equalized stimulus was designed and the OAE responses were analyzed and compared to conventional click evoked OAEs. The equalized swept-tone stimulus evoked greater magnitude OAE responses when compared to the conventional methods. It was also able to evoke responses in subjects that had little TEOAEs which might fail conventional hearing screening.

High resolution sampling was performed along the Ü
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Formation exposed near the YeniceSihlar village of Mudurnu (Bolu). Field and thin-section analyses showed that the Ü
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Formation is composed of cm to m scale cycles of 4th and 5th order. The 4th order cycles are equivalencies of parasequences and have 0.4 Ma average duration. 5th order cycles are interpreted as episodic. Upper Albian (OAE1c or OAE1d) and Cenomanian/Turonian (OAE2) anoxic events are observed as black shale levels in the studied section. Position of black shale levels is interpreted using cyclostratigraphy and sequence stratigraphy. Four types of cycle are determined. A and B-type cycles are placed in transgressive and Highstand System Tract. C and D-type cycles are placed in Lowstand System Tract. Two type 3 and one type 1 sequence boundaries are recorded. The boundary between the Sogukç
am Limestone and the Ü
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Formation is interpreted as the first type 3 sequence boundary. The second one separates the Ü
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Formation and the Yenipazar Formation and is observed at the top of the section. Type 1 boundary is represented by a conglomeratic level in the middle of the succession. Provenance analysis of sandstones indicates that during the Cenomanian the source area changed from magmatic arc setting to continental setting.

The construction sector presents a historic of problems related to the quality of its products, services and processes. Many researches and initiatives against such problems have been conducted by researchers, professionals and organizations from the wide field covered by this sector.Making use technological innovations, methods and tools adapted from other industrial sectors and experiences gathered from development of the design and execution processes, the construction sector in Brazil has shown progress on the performance improvements, due to efforts undertaken in the last decades, mainly on the building construction segment.Part of the solutions to these problems points to the need of improvement in the management mechanisms of the design process and the integration between the design and execution activities. This research takes this field for granted, leading the focus to the special art constructions, expression used to kinds of constructions such as bridges and viaducts. The methodology of the case study was used to attend of a large sized viaduct project development in which some basics of the Concurrent Engineering are evaluated in order to improve the quality of the product and also of other processes involved in construction sector. This approach is based on the methods and tools studied on the literature revision; in the specific features of the sector, completed by a research done with the professionals of the bridges and viaducts designs; and also by the analysis of the case study emphasizing the aspects of the design-production integration in the design process, besides a discussion about the way of contracting engineering services. The case study shows that a bigger integration between design and production using the Concurrent Engineering concepts, has allowed the constructive rationalization and the decrease of the costs in the construction.
O setor da construção apresenta um histórico de problemas relacionados à qualidade de seus produtos, serviços e processos. Vários estudos e iniciativas para o combate de tais problemas têm sido conduzidos por pesquisadores, profissionais e organizações do vasto campo de atuação abrangido por este setor. Utilizando-se de inovações tecnológicas, métodos e ferramentas adaptados de outros setores industriais e das experiências acumuladas no desenvolvimento dos processos de projeto e execução, o setor da construção no Brasil tem revelado avanços no que diz respeito à melhoria de desempenho, graças aos esforços empreendidos nas últimas décadas, principalmente no segmento da construção de edifícios.Parte das soluções para esses problemas aponta para a necessidade do aperfeiçoamento dos mecanismos de gestão do processo de projeto e a integração entre as atividades de projeto e execução. O presente trabalho de pesquisa adota essa linha como princípio, direcionando o foco para as Obras de Arte Especiais (OAE),denominação utilizada para caracterizar tipos de construções como pontes e viadutos.A metodologia de estudo de caso foi empregada para o acompanhamento do desenvolvimento do projeto de um viaduto de grande porte, no qual os conceitos da Engenharia Simultânea são avaliados como alternativa para a melhoria da qualidade do produto e dos demais processos envolvidos no setor da construção.Essa abordagem é baseada nos métodos e ferramentas estudados na revisão de literatura; na consideração das características específicas do setor, complementadas pela pesquisa com os profissionais de projeto de OAE; e pela análise do estudo de caso com ênfase nos aspectos da integração projeto - produção no processo projetual,além de uma discussão sobre as formas de contratação dos serviços de engenharia.O estudo de caso demonstra que uma maior integração entre projeto e produção, utilizando pressupostos da Engenharia Simultânea, permitiu a racionalização construtiva e a redução de custos da obra.

This thesis deals with encryption of short text message (SMS) in mobile communication. Introduction is dedicated to overview of the parts of GSM radiotelephone nets and SMS messages transfer . Next chapter is reserved for description of cryptographic methods especially symetric and asymetric encryptografic aproaches. A design of a SMS messages encryption and decryption techniques is in next. For SMS encryption and sign, there is used the asymetric cypher RSA. Encryption use OAEP padding schema. The public key is saved in certificate. The Symbian OS has been choosen as a suitable platform for programming of mobile devices.

The Cretaceous period was affected by global perturbations (e.g., the Cenomanian-Turonian Oceanic Anoxic Event), which led to widespread changes in the ocean-climate system. Primary trophic levels (e.g., calcareous and other mineralized plankton) experienced accelerated rates of speciation and extinction at or near these events. Investigating the composition of fossil ichthyofaunas is crucial to reconstruct the changes induced by these disruptions in the higher trophic levels (e.g., fish communities), whose interpretation remains elusive. The broad ecological range occupied by actinopterygians today was probably quite similar in the Cretaceous because no other vertebrate groups competed with actinopterygians in their niches at that time. Considering the range of ecosystems occupied today by actinopterygians as being representative of the paleoecology of ray- finned fishes in the Cretaceous, they form a good proxy to study how vertebrates responded to global changes during the last half of the Mesozoic. In northeastern Italy, the upper Cenomanian Bonarelli Level and the Turonian-Coniacian “lastame” (Scaglia Rossa Formation) yielded diversified and well- preserved ichthyofaunas that recorded the fish assemblage composition in the Cenomanian-Turonian interval. The aim of this thesis is the study of the composition of these poorly known Tethyan assemblages, evidencing their diversity and ecological structure and comparing them to coeval assemblages. This study will hopefully provide significant data for adding new tiles for the reconstruction of the effects of the Cretaceous climatic disruptions on the higher trophic levels in the Tethyan domain.

Les Evénements Océaniques Anoxiques (OAE) sont des événements extrêmes qui se sont pro- duits majoritairement durant le Crétacé et qui sont caractérisés par un enfouissement massif et brutal de carbone organique. Ces événements ont été très étudiés durant ces 40 dernières années mais aucun consensus n’a été atteint quand aux processus à l’origine de leur déclenchement. Pour tenter de répondre aux questions encore en suspens, nous avons réalisé une étude géochimique approfondie (éléments majeurs et traces, compositions isotopiques en Nd et Hf) des différentes fractions (détritiques et authigènes) de sédiments marins déposés lors de l’événement océanique anoxique associé à la limite Cénomanien-Turonien (OAE2, 93.5Ma). Les deux sections étudiées représentent différents environnements de dépôt : un environnement peu profond et proche des sources continentales (Taghazoute, Maroc) et un environnement marin profond, loin des côtes (DSDP Site 367, Cap-Vert).A l’approche de l’OAE2, les compositions isotopiques du Nd et de l’Hf ne présentent que peu de variations. Ces observations reflètent une absence de changement dans le régime d’érosion continentale en amont des deux sections étudiées. Notre étude diverge du scenario proposant qu’un fort apport de nutriments résultant d’une altération continentale accrue soit à l’origine des OAEs. En revanche, les variations isotopiques (Nd) mesurées dans les fractions authigènes du Site 367, interprétées comme reflétant la composition océanique passée, supportent l’idée d’une contribution magmatique dans l’Océan Atlantique durant l’OAE2. Ces nouveaux résultats sont cohérents avec de précédentes études et confortent le rôle des grandes provinces magmatiques (plateau des Caraïbes) dans l’eutrophisation des océans qui précède les événements anoxiques.En outre, l’étude combinée des terres rares (REE) et des compositions isotopiques (Nd) de fractions authigènes obtenues par extraction chimique (leaching) démontre l’incorporation de matériel détritique dans ces fractions en milieu peu profond. Ces nouvelles observations questionnent l’idée que toute fraction authigène enregistre une composition chimique océanique pure. Enfin, l’étude complète des concentrations en éléments traces de ces mêmes fractions souligne le rôle important de la lithologie des sédiments sur la composition des leachates. Cette étude questionne également l’utilisation de certaines méthodes de leaching qui semblent favoriser l’extraction de phases détritiques externes lorsque les sédiments sont soumis à des étapes de leaching répétées
Oceanic Anoxic Events (OAE) are brief and extreme events that mostly occurred during the Cretaceous and are defined by the burial of massive amounts of organic carbon. These events have been intensely investigated in the last 40 years but the mechanism that triggered OAEs remains problematic. In order to better constrain what causes these events, we realised a complete geochemical study (major and trace elements, isotopic compositions of Nf and Hf) of various sedimentary fractions (detrital and authigenic) for marine sediments associated with the Cenomanian-Turonian boundary event or OAE2 (93.5 Ma). We focused our study on two marine sections that represent different depositional settings : a shallow marine setting, close to the continental shelf (Taghazoute, Morocco) and a abyssal marine section (DSDP Site 367, Cape-Verde), far from the African shelf.The remarkable stability of the Nd-Hf decoupling in both sections indicates no obvious change of continental weathering approaching OAE2. Our conclusions diverge from the hypothesis that proposes an higher nutrient input through an enhanced continental weathering as a triggering mechanism of OAEs. However, Nd isotopic compositions of authigenic fractions measured at Site 367, interpreted as past oceanic composition, exhibit a positive isotopic excursion and indicate a magmatic contribution in the deep Atlantic Ocean during OAE2. These new data are consistent with previous isotopic studies and support the role of Large Igneous Province (in our case, the Caribbean Plateau) as nutrient provider and triggering mechanism of anoxic events.The combined study of rare earth elements (REE) and Nd isotopic compositions of authigenic fractions recovered by leaching demonstrates the incorporation of detrital material in authigenic fractions in shallow marine settings. These new results challenge the traditional belief that authigenic material always records an untouched seawater composition. Finally, the extensive study of trace element concentrations of these same fractions demonstrated the strong impact of sample lithology on their trace element content. Our study also questions the relevance of sequential leaching methods that facilitate external contamination when sediments are submitted to repeated leaching steps

An important episode of carbon sequestration, Oceanic Anoxic Event 1a (OAE-1a), characterizes the Lower Aptian worldwide, and is mostly known from deeper-water settings. The present work of two Lower Aptian deposits, Madotz (N Spain) and Curití Quarry (Colombia), is a multiproxy study that includes fossil assemblages, microfacies, X-ray diffraction bulk and clay mineralogy, elemental analyses (major, minor, trace elements), Rock-Eval pyrolysis, biomarkers, inorganic and organic carbon content, and stable carbon isotopes. The results provide baseline evidence of the local and global controlling environmental factors influencing OAE-1a in shallow-water settings. The data also improve our general understanding of the conditions under which organic-carbon-rich deposits accumulate. The sequence at Madotz includes four intervals (Unit 1; Subunits 2a, 2b and 2c) that overlap the times prior to, during and after the occurrence of OAE-1a. The Lower Unit 1(3m thick) is essentially siliciclastic, and Subunit 2a (20m) contains Urgonian carbonate facies that document abruptly changing platform conditions prior to OAE-1a. Subunit 2b (24.4 m) is a mixed carbonate-siliciclastic facies with orbitolinid-rich levels that coincides with OAE-1a δ13C stages C4-C6, and is coeval with the upper part of the Deshayesites forbesi ammonite zone. Levels with pyrite and the highest TOC values (0.4-0.97%), interpreted as accumulating under suboxic conditions, and are restricted to δ13C stages C4 and C5. The best development of the suboxic facies is at the level representing the peak of the transgression. Subunit 2c, within δ13C stage C7, shows a return of the Urgonian facies. The 23.35-m section at Curití includes a 6.3-m interval at the base of the Paja Formation dominated by organic-rich marlstones and shales lacking benthic fossils and bioturbation, with TOC values as high as 8.84%. The interval overlies a level containing reworked and phosphatized assemblages of middle Barremian to lowest Aptian ammonites. The range of values and the overall pattern of the δ13Corg (-22.05‰ to -20.47‰) in the 6.3m-interval is comparable with Lower Aptian δ13C stage C7. Thus, conditions of oxygen depletion at this site also occurred after Oceanic Anoxic Event-1a, which developed between carbon isotope stages C3 and C6. Both sites, Madotz and Curití, attest to the importance of terrigenous and nutrient fluxes in increasing OM productivity that led to episodic oxygen deficiency.

This study assessed the role of otoacoustic emission screening for the early identification of noise-induced hearing loss in South African mineworkers. Transient otoacoustic emissions and distortion product otoacoustic emissions were recorded in 106 noise exposed mineworkers (212 ears) aged between 20 and 55 years, and in 17 non-exposed novice workers (34 ears) aged between 18 and 29 years. All subjects had normal hearing acuity, otoscopic examinations and immittance measurements. Four otoacoustic emission (OAE) measurements were taken per ear and repeated by a second audiologist for the evaluation of inter-test reliability. Age and number of years of noise exposure was additionally evaluated as well as the specificity and sensitivity of the tests for this population group. In general the OAEs were diminished at four KHz for both the exposed and non-exposed groups. Age was found to be the primary predictor of diminished OAE tracings. Poor inter-test reliability was obtained. These results indicate that further research is required within this population group before OAE testing can be implemented for screening for noise-induced hearing loss.
Dissertation (M (Communication Pathology))--University of Pretoria, 2006.
Speech-Language Pathology and Audiology
Unrestricted

This thesis focuses on structural remodelling and security proof of cryptographic schemes. A message pre-processing, also known as asymmetric message padding, is an essential step in asymmetric encryption which is heavily used in secure banking applications. In this thesis, we propose new effective padding schemes and able to mitigate the various computation and memory overhead compared to previous works. We are also able to provide streaming capability which was missing in most of the previous works. Mathematical security proof of proposed schemes justifies their security.

One major reason of CNS pharmacotherapy's impediment is the existence of "barriers" between blood and CNS, especially the Blood-Brain Barrier (BBB), a neurovascular structure localized at the level of brain microvasculature. Main factors responsible for this barrier function are drug efflux transporters type ABC (ATP-Binding Cassette) and SLC (SoLute Carrier) expressed at BBB level and known to be at the origin of multi-drug resistance phenomenon. Recent researches aim at unraveling the signaling mechanisms regulating these transporters in order to modulate their activity and improve pharmacotherapy in brain diseases. For years, these transporters have been studied in adult organism. But, there is a wide spread belief that the BBB in embryo, fetus, new born and infant is "immature", implying caution in giving drugs to infants. However, current knowledge on the functional status of the BBB in immature organism remains very limited.This study was performed in the aim of understanding: 1) The ontogenesis of ABC and SLC transporters during brain maturation, 2) the functional role of four BBB drug efflux transporters (P-glycoprotein (P-gp), Breast Cancer Resistance Protein (bcrp), Organic Anion Transporter 3 (oat3), and Transporting Peptide 1a4 (oatp1a4) transporters) in children's brain, and 3) the mechanisms that regulate their functional expression under normal and pathological conditions, mostly under inflammatory conditions, because indeed alterations in structural and functional components of the BBB have been reported in a long list of CNS pathologies in adults. Our results showed changing properties of the BBB during ontogenesis, as well as an age-related differential regulation of BBB drug efflux transporters under normal and inflammatory conditions.These findings highlight the importance of considering an age-related response of CNS to drugs and of taking into account the specific properties of juvenile BBB during definition of therapeutic strategies designed to treat childhood brain diseases, and this in the clinical perspective of developing new drugs with enhanced efficacy in children's CNS.

Le géothermomètre Δ47 est basé sur la relation entre l’abondance des liaisons 13C–18O des carbonates et la température de calcification. Ce proxy contourne potentiellement les limites des autres thermomètres (δ18O, Mg/Ca) pour reconstruire les paléo-températures des océans, expliquant son développement exponentiel depuis dix ans. Cette thèse teste pour la première fois le potentiel et les limites de la thermométrie Δ47 sur les coccolithes, des nannofossiles calcaires produits par des organismes calcifiants dans la zone photique. Ces biominéraux calcitiques et ubiquistes constituent une part importante de l’archive sédimentaire. Des cultures in vitro nous ont permis d’établir que trois espèces de coccolithes actuelles enregistrent la même relation Δ47 – T que la calcite inorganique, alors qu'elles présentent de très larges effets vitaux en δ18O (±5‰). Nous concluons que ces espèces de coccolithes d'importance géologique ne présentent pas d’effets vitaux en Δ47. Nous avons ensuite appliqué le Δ47 à l’étude des sédiments enregistrant l’événement d’anoxie océanique du Toarcien (–183 Ma) au cours duquel les reconstructions de températures restent encore ambigües, notamment du fait de la méconnaissance de la composition isotopique en oxygène de l’eau de mer. Sur la base des données Δ47 acquises, nous proposons des températures élevées (de l’ordre de 36°C), mais restant relativement stables sur l'intervalle d'étude. En couplant ces températures aux données de δ18O des carbonates, nous suggérons une variation importante du δ18O de l'eau de mer dans le Bassin de Paris lors de la mise en place des faciès black shales. Enfin, sur des sédiments pélagiques subactuels, l’une des espèces étudiées présente des déséquilibres isotopiques en Δ47 non observés en culture et explicables par d’autres paramètres environnementaux comme l’intensité lumineuse. Cette thèse illustre le potentiel du thermomètre Δ47 des coccolithes en différents contextes, ouvrant un vaste champ d’application de reconstruction des paléo-environnements sur le Méso-Cénozoïque
The Δ47 geothermometer relies on the relationship between the 13C–18O abundance in carbonateand temperature of calcification. This proxy has the potential to overcome limitations of other thermometers(δ18O, Mg/Ca) to reconstruct oceanic paleotemperatures. This thesis evaluates for the first time the potentialand the limitations of the Δ47 thermometry of the coccoliths, the calcareous nannofossils produced byorganisms calcifying in the photic zone. These calcitic and ubiquitous biominerals represent an importantpart of the sedimentary archive. In vitro cultures allow us to establish that three modern coccoliths speciesrecord the same Δ47–T relation than inorganic calcite, although exhibiting substantial δ18O vital effects(±5‰). We conclude that these coccoliths species do not present any Δ47 vital effect. We subsequentlyapplied the Δ47 proxy to sediments from the Toarcian oceanic anoxic events (–183 Ma) during which thetemperatures reconstructions are still elusive, mainly due to the unknown oxygen isotopic composition ofseawater. On the basis of our Δ47 data, we infer relatively high, yet steady temperatures (around 36°C) duringthe examined interval. By combining these Δ47-derived temperatures to carbonate δ18O data, we can suggestdrastic change in the seawater δ18O composition in the Paris Basin at the onset of black shale deposition. Acore top calibration of Δ47 of coccoliths revealed that one of the studied cultured species exhibits Δ47disequilibrium that is accountable by other environmental parameters, such as light irradiance in the naturalenvironment. Thus, this thesis illustrates the potential of the coccolith Δ47 thermometer in different settings,opening a wide range of application to reconstruct the palaeoenvironments over the Meso-Cenozoic Eras

Background: Iron deficiency, anemia, and iron excess have been associated with altered hearing functions in children and adults. Animal studies suggest that iron deficiency during pregnancy negatively affect fetal auditory development. The relationship between maternal iron status and auditory functions in healthy term newborns has not been clearly elucidated among humans. The goal of this pilot study was to determine the relationship between markers of iron status during pregnancy and brainstem auditory function in healthy neonates. Methods: Pregnant women who gave birth at the Montfort Hospital were recruited to take part in this study (n=6). Within two weeks after birth, their newborn’s hearing function was assessed by wave amplitude, latency and inter-latency from the Auditory Brainstem Response (ABR) test. Markers of iron status, namely hemoglobin (Hb) and mean corpuscular volume (MCV), were collected retrospectively for the first and second trimester from the women’s medical chart. Results: Overall, no significant relationship was observed between maternal Hb and MCV concentrations and newborns auditory function. Although two significant Spearman correlations were observed (MCV and inter-latency I-V; r=0.87; p=0.005 and Hb and amplitude V; r=0.89; p=0.04), these findings may be due to chance because of multiple testing and the small sample size. Conclusion: Although iron is a key nutrient involved in the brain and auditory system development, we were not able to demonstrate a relationship between iron status during pregnancy and newborn hearing function. Prospective or intervention studies with a larger sample size and with more specific iron markers (ex. ferritin) are required to confirm these findings.

The difference in otoacoustic emission (OAE) hearing screening failure rates as a function of ethnic category was investigated in a population of newborns at Tampa General Hospital, Tampa, Florida. Clinical observation led to a concern that due to a higher incidence of outer and middle ear dysfunction in Hispanic newborns and children, screening could result in disparate failure rates, with a larger number of these infants requiring further testing. This result would warrant changes in current protocols, as well as screener training,and parent counseling practices. Between January and July of 2000, 1407 newborns were tested utilizing distortion product otoacoustic emission screening protocols. Of those infants,only 68 failed, yielding a higher than average overall program referral rate of 5%. It is hypothesized that since later reported referral rates for this program fall below 1%, the individuals performing the screenings had not yet become experienced enough to yield low refer rates. In addition, initial screens are not repeated in this program due to staffing and funding issues, which may contribute to higher than average fail rates. More important, however, results indicated that there is indeed a difference in failure rates as a function of ethnicity, with a greater proportion of Hispanic and African-American and "Other" newborn referrals that Caucasian or Asian newborns. This difference, however, was not significantly reliable. It is hypothesized that this difference may be the result of a generally lower socioeconomic status and access to medical care within urban minority populations in Hillsborough County, Florida. Implications are discussed.

Rare earth elements (REEs) and their isotopes (such as Nd isotopes) can be potentially used to trace a wide range of oceanic processes in both modern and ancient oceans, but their successful application as tracers requires a comprehensive understanding of REE cycling in the modern ocean. Previous studies of REEs in seawater were largely constrained by analytical difficulties in generating accurate and precise REE data from seawater, which typically contain REE concentrations at a sub-ppt to ppt level. A new, and relatively simple, analytical method for precise and accurate determination of all dissolved REE concentrations in reasonably small (∼100 ml) seawater samples is presented in this thesis. With the application of the new method, this thesis reports the first full-depth, zonal ocean section of all dissolved REE concentrations, collected during the CoFeMUG cruise along ∼12°S in the South Atlantic. The section approach of this study places the distribution of dissolved REE concentrations in a well-constrained hydrographic context, allowing the first quantitative assessment (by an inverse model) of the relative importance of hydrographic controls resulting from advection/mixing of ocean circulation, together with non-conservative controls resulting from local particle scavenging and remineralization, in controlling the distribution of dissolved REEs in this region. A noteworthy decoupling of Ce and Mn with respect to their cycling in the water column was also observed in this study. The application of Nd isotopes as a tracer to reconstruct changes in ocean circulation in the NW European chalk shelf sea during rapid climatic events, including the mid-Cenomanian Event and oceanic anoxic event 2 (OAE 2), suggests a tight coupling between ocean circulation and transient climatic cooling during the general warm Late Cretaceous. An advected volcanic signal during OAE 2 was registered in the seawater Nd-isotope record from the English Chalk, probably suggesting a period of enhanced ocean ventilation/mixing at this time.

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

La Terra durante il Cretaceo (145.5-65.5 Ma) ha sperimentato lunghi periodi di clima caldo con temperature molto più elevate rispetto ad oggi. Il continuo sviluppo di Grandi Province Ignee (LIP) e il riassetto globale dei confini di placca ha portato ad un aumento dei livelli atmosferici di gas serra (CO2 e in alcuni casi CH4) e fasi di limitata circolazione oceanica. Il riscaldamento globale e l'aumento abnorme di CO2 hanno cambiato sensibilmente gli equilibri del ciclo del carbonio, alterando così il ciclo idrologico, la distribuzione dei nutrienti, l'intensità dell’upwelling e la formazione di acque profonde. Il record geologico dell’intervallo di tempo compreso tra il tardo Albiano e il Turoniano basale (~ 104-92 Ma) rappresenta un laboratorio naturale particolarmente intrigante per comprendere i processi fisici, chimici e biologici che hanno agito nel corso di questo periodo, caratterizzato dall’alternarsi di fasi di relativo equilibrio e fasi di alterazione del ciclo del carbonio. L’intervallo tra il tardo Albiano e il Turoniano basale è caratterizzato da tre grandi anomalie geochimiche corrispondenti alle escursioni positive della curva isotopica del carbonio: l’Evento Anossico 1d (OAE1d), l’Evento Cenomaniano Medio (MCE) e l’Evento Anossico 2 (OAE2). Questo studio, tramite l’integrazione di dati sedimentologici, geochimici (isotopi del carbonio e dell’ossigeno, geochimica inorganica e organica) e ciclostratigrafia ad alta risoluzione, offre un'indagine integrata delle dinamiche paleo-ambientali e climatiche che accompagnarono questi grandi eventi. Particolare enfasi è volta alla comprensione dell’interazione tra i cambiamenti che avvengono nelle acque superficiali e i processi che agiscono sul fondo mare, con lo scopo di meglio definire il comportamento delle masse d'acqua in condizioni ambientali /climatiche estreme. Come archivi naturali delle passate condizioni oceanografiche e ambientali sono state scelte cinque sezioni pelagiche Tetidee chiave: quattro dal Bacino Umbro-Marchigiano (Furlo, Contessa, Le Brecce, Monte Petrano - Italia centrale) e una dal Bacino di Belluno (Cismon - Italia settentrionale). La descrizione sedimentologica ad alta risoluzione delle cinque sezioni – dalla scala di terreno fino alla scala microscopica- ha condotto ad una migliore comprensione dei processi fisici che hanno agito sul fondo marino durante la deposizione delle sequenze studiate. La presenza di peculiari strutture e facies sedimentarie indica che la sedimentazione pelagica non è esclusivamente governata dalla decantazione di particelle biogeniche. Correnti di fondo di intensità crescente e calante in modo ciclico ridistribuiscono attivamente i sedimenti presenti, formando facies specifiche e riconoscibili. Al fine di considerare anche questo processo, è stato definito un nuovo modello deposizionale per le contouriti carbonatiche pelagiche. Nuovi dati isotopici ad alta risoluzione dell’ossigeno e del carbonio sia su carbonato che su materia organica sono stati prodotti per le sezioni del Monte Petrano e del Cismon. Il profilo ad alta risoluzione di δ13C presenta tre escursioni positive in corrispondenza dell’OAE1d, MCE ed OAE2. Inoltre, la correlazione dettagliata con ulteriori profili isotopici editi ed inediti disponibili per le altre sezioni studiate ha permesso di definire con maggiore accuratezza l’inquadramento stratigrafico a scala di bacino. Importanti variazioni litologiche sono associate alle escursioni isotopiche del carbonio (CIE). Alcuni strati spessi pochi centimetri di scisto nero sono associati all’Evento Pialli (OAE1d) mentre l'impressionante livello Bonarelli è l'espressione litologica dell’OAE2. L’evento MCE costituisce, invece, un enigma più sottile e intrigante. E’ stata così ricostruita la variazione verticale stratigrafica delle facies identificate e messa in relazione ai principali eventi geologici. L'interazione dei processi paleoceanografici che controllano la composizione dei sedimenti in combinazione con la distribuzione dei sedimenti da parte delle correnti ha generato caratteristici stacking pattern. Per le sezioni del Cismon e del Monte Petrano sono stati prodotti anche dati geochimici degli elementi maggiori e in traccia (XRF), al fine di comprendere meglio i cambiamenti paleoambientali che hanno caratterizzato questi due bacini adiacenti tra loro. Tutte le sezioni del Bacino Umbro-Marchigiano sono state analizzate con tecniche ciclostratigrafiche, che hanno potuto mettere in luce quanto le variazioni di produttività primaria, rappresentata dalla variazione ciclica di carbonato e litologie silicee, riflettano la risposta climatica, oceanografica e deposizionale ai cicli orbitali. La caratterizzazione sedimentologica altamente dettagliata è stata fondamentale per comprendere appieno la sedimentazione pelagica nella Tetide occidentale, durante le fasi di condizioni sia stabili che perturbate. Sulla base dei dati bio-, chemo- e ciclostratigrafici, l’evoluzione delle facies è stata datata con precisione ed è stata stimata la durata degli eventi. Questo approccio multi-proxy è stato fondamentale per caratterizzare un ambiente sedimentario apparentemente omogeneo e monotono ma in realtà estremamente dinamico. Questo studio fornisce un importante passo verso una più completa comprensione dei meccanismi all'origine degli eventi paleoceanografici del ‘Cretaceo medio’, tra cui i fattori che innescano i cambiamenti anossia-disossia e ristabiliscono condizioni stabili a varie scale temporali.
Earth during the Cretaceous (145.5-65.5 My) experienced long-lasting periods of warm climate with temperatures much higher than today. The continuous development of Large Igneous Provinces and the global rearrangement of plate boundaries led to an increase in atmospheric levels of greenhouse gasses (CO2 and possibly CH4), and times of restricted ocean circulation. Global warming and the abnormal increase in CO2 changed the equilibria of the carbon cycle thus altering the hydrologic cycle, nutrients distribution, upwelling intensity and deep water formation. The geological record of the late Albian to early Turonian (~104-92 My) time interval represents a particularly intriguing natural laboratory to understand the physical, chemical and biological processes that acted during a period of alternated phases of relative equilibrium and carbon cycle perturbations. The late Albian to early Turonian time interval is characterized by three major geochemical anomalies corresponding to positive excursions of the stable carbon isotope profile: the Oceanic Anoxic Event 1d (OAE1d), the Mid-Cenomanian Event (MCE) and the Oceanic Anoxic Event 2 (OAE2). This study, combining sedimentological, geochemical (C and O isotopes, inorganic and organic geochemistry) and high-resolution cyclostratigraphic data, provides an integrated investigation of paleoenvironmental and climatic dynamics accompanying these major events. The interplay of surface water changes and sea bottom processes are here discussed with the purpose of better defining how water masses react during highly stressed climatic/environmental conditions. Five pelagic Tethyan key-sections, four from the Umbria-Marche Basin (Furlo, Contessa, Le Brecce, Monte Petrano – central Italy) and one from the Belluno Basin (Cismon – northern Italy), were chosen as natural archives of the past oceanographic and environmental conditions. The extremely detailed field- to microscopic-scale sedimentological description of the five sections allowed a better comprehension of the physical processes that acted on the sea-floor during the deposition of the studied sequences. Peculiar sedimentary structures and facies indicate that settling of biogenic particles wasn’t the only physical process controlling pelagic sedimentation. Waning and waxing cycles of bottom currents actively redistributed sediments, forming specific facies. In order to account for this process, a new depositional model for calcareous pelagic contourites was established. New high-resolution oxygen, carbonate- and organic-carbon isotope record were produced for Monte Petrano and Cismon sections. High-resolution δ13C record exhibits three positive excursions in correspondence of OAE1d, MCE and OAE2. The detailed correlation with published and unpublished isotopic data from the other studied sections better defines the basin-scale stratigraphic framework. Important lithological changes are associated with the observed carbon isotopic excursions (CIEs). Few centimeter thick black shale layers are associated with the Pialli Event (OAE1d) and the impressive Bonarelli Level is the lithologic expression of the OAE2. The MCE corresponds, instead, to more subtle and intriguing conundrum. A stratigraphic vertical variation of the identified facies was reconstructed and linked to the major geologic events. The interplay of the paleoceanographic processes controlling the sediment composition combined with current-driven sediment distribution resulted in characteristic cyclic patterns. Major and trace element geochemical data were produced for Cismon and Monte Petrano sections in order to better understand the paleoenvironmental changes that characterized these two adjacent basins. The application of cyclostratigraphic techniques to all the studied sections from the Umbria-Marche Basin shows that primary productivity variations, represented by the cyclic alternation of carbonate and siliceous lithologies, reflect the climatic, oceanographic and depositional response to orbital cycles. Highly detailed sedimentological characterization was central to fully comprehend the pelagic sedimentation in Western Tethys during times of stable and perturbed conditions. Based on bio-chemo- and cyclostratigraphy, facies evolution was precisely dated and event duration was estimated. This multi-proxy approach was proved vital to characterize an apparently homogenous and monotonous sedimentary environment that was indeed extremely dynamic. This study provides an important step towards a more comprehensive understanding of the mechanisms at the origin of ‘mid-Cretaceous’ paleoceanographic events, including feedbacks to trigger anoxia-dysoxia and re-establish normal conditions at various time scales.

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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.

Text in Afrikaans
In die post-koloniale tydsgewrig was die menseregte-situasie en bestaansomgewing van talle Afrikane die van konflik, korrupsie, onderdrukking, sosiale ongeregtigheid en menseslagting. As kontinentale eenheidsorganisasie het die OAE jare lank in gebreke gebly om die lot van mense in sy ledestate te verbeter. Eers teen die laat-sewentigerjare het die organisasie - hoofsaaklik as gevolg van internasionale druk - begin om werklik aan menseregte aandag te skenk. Die kulminasie hiervan was die Banjoel-handves vir menseregte in 1981. Dit is egter bekend dat die gebeure geen wesenlike verbetering en vordering in die menseregte-gesteldheid in Afrika teweeg gebring het nie. Teen hierdie agtergrond is gepoog om die geskiedenis van menseregte in Afrika en die OAE se rol hieromtrent te ontleed. Samehangend is ondersoek gedoen na die noodsaaklike elemente vir 'n menseregtebedeling op die kontinent - soos dit in der waarheid in die Banjoel-handves ten doel gestel is. Die belangrikste bevindings is onder meer dat * 'n botsing tussen pan-nasionale en nasionale belange in die OAE deurgaans ten diepste veroorsaak het dat die organisasie in gebreke was om die lot van talle Afrikane te verbeter; * die politieke bedelings en "regskultuur" van die afsonderlike Afrika-state tot dusver verhoed het dat die menseregte van die Banjoel-handves sinvol toegepas word; * indien die OAE sy menseregte-standaarde toegepas wil sien, die Afrika-leiers in afsonderlike verband eers daarmee erns moet maak; * gemeenskaplik aanvaarde politieke bedelings en legitieme regerings in Afrika voorwaardelik is vir die verwerkliking van die ideaal van 'n menseregte-bedeling op die kontinent. Sedert die negentigerjare is daar egter tekens wat hoop bied op 'n verbetering in die menseregte-situasie in Afrika. Dit geld veral vir die demokratisering van etlike state en die werksaamhede van die OAE se Menseregte-kommissie. Weens verskeie redes sal die organisasie se taak ten opsigte van menseregte vorentoe egter nie maklik wees nie. Die hoop beskaam egter nie dat die OAE, hoe gering ook al, 'n bydrae kan !ewer om die bestaansomgewing van talle Afrikane te verbeter - mits 'n groter realisme daaroor in die afsonderlike ledestate posvat.
In the post-colonial era the human rights situation of many Africans was one of conflict, repression, social injustice and bloodshed. For years the OAU failed to improve the lot of people in its member states. It was only during the late seventies that the OAU - mainly as a result of international pressure - began to pay attention to the principles of human rights. The culmination of this was the Banjul Charter of human rights in 1981. This brought about no real progress or improvement in the human rights situation in Africa, however. Against this background an attempt has been made to analyse the history of human rights in Africa and the role of the OAU in this regard. At the same time the essential elements of a human rights dispensation on this continent - as it has in fact been envisaged by the OAU - have been investigated. The most important findings include the following: * a clash between pan-national and national interests in the OAU was a fundamental reason why this organisation failed to improve the lot of Africans; * the political dispensations and "legal culture" of the African states have thus far prevented the meaningful application of the Banjul charter; * if the OAU wishes to see its human rights standards applied, the African leaders will first have to make serious attempts to do this separately and individually; * commonly accepted political dispensations and legitimate governments will have to be established in the OAU member states before the ideal of a human rights dispensation can become a reality in Africa. Since the nineties there have, however, been signs offering hope for an improvement in the human rights situation in Africa. This applies in particular to the democratisation of numerous states and the activities of the OAU's Human Rights Commission. For various reasons the future task of this organisation in regard to human rights will not be easy. There is hope, however, that the OAU will be able to make some contribution, however slight, to improving the environment of many Africans - provided a greater realism about this matter sets in the respective member states.
Political Sciences
D. Litt. et Phil. (Internasionale Politiek)