Dissertations / Theses on the topic 'Channel responses'
To see the other types of publications on this topic, follow the link: Channel responses.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Channel responses.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Tu, Denise Shao-Wai. "Assessment of Methods for Monitoring Responses to River Restoration: Riverbed and Channel Form Changes." Thesis, University of Oregon, 2011. http://hdl.handle.net/1794/11505.
Full textAbstract:
xi, 54 p. : ill. (some col.)On the Middle Fork John Day River (MFJD), a low gradient, meandering river in eastern Oregon, restoration includes engineered log structures intended to increase in-stream complexity and habitat diversity. Effects of log structures on riverbed topography can be captured through repeat topographic surveys, digital elevation model (DEM) of differencing (DoD), and aerial imagery. This study evaluates the (1) potential for remote sensing analysis, (2) effect of survey point density on DEMs, and (3) application of DoDs, in monitoring riverbed changes in the MFJD. An average point spacing and density finer than 0.50m and 1.25pts/m
Committee in charge: Patricia McDowell, Chairperson; Andrew Marcus, Member
2
Achike, Francis Ifejika. "The cardiovascular responses to calcium channel blockers in rats subjected to blood gas/pH changes." Thesis, [Hong Kong] : University of Hong Kong, 1990. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12937095.
Full text
3
Rosick, Edward R. (Edward Rudolph). "Effect of Calcium Channel Antagonists and Other Agents on Olfactory Reception." Thesis, North Texas State University, 1985. https://digital.library.unt.edu/ark:/67531/metadc503999/.
Full textAbstract:
The role of Ca++ in olfactory responses was investigated with inorganic and organic calcium channel antagonists. Electrophysiological responses to odorants were recorded from frog olfactory mucosa before and after aerosol application of different agents. Electroolfactogram responses were blocked by certain inorganic ions with the order of effectiveness Zn++ >Ln+++>Cd++>Ca++>Co++>Sr++>Mg++. Ba++ potentiated olfactory responses, and is known to potentiate calcium channel-mediated responses in other tissues. Certain local anesthetics which are thought to act through calcium channel blockade were inhibitory to olfactory responses, with the order of effectiveness being dibucaine>tetracaine>procaine. These data support the idea that Ca++ is involved in olfaction, perhaps acting as a current carrier and/or a second messenger. Preliminary experiments on channel localization were performed using a silicon-labeled amine. Attempts to localize the silicon label were inconclusive, although silicon was detected in the olfactory tissue.
4
DIAS, MAURICIO HENRIQUE COSTA. "ACTUAL MOBILE RADIO PROPAGATION CHANNEL RESPONSES ESTIMATES IN THE SPATIAL AND TEMPORAL DOMAINS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2003. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=3502@1.
Full textAbstract:
INSTITUTO MILITAR DE ENGENHARIANo cenário atual das telecomunicações móveis, os arranjos de antenas voltaram a receber grande atenção dos pesquisadores, especialmente quando esquemas adaptativos de modificação de seus diagramas de radiação são utilizados. Uma das aplicações que exploram o potencial dos arranjos de antenas é o seu uso como forma de aumentar consideravelmente a eficiência espectral dos sistemas móveis atuais e da próxima geração. A outra aplicação em evidência está voltada para sistemas de localização de posição, pois algumas das técnicas conhecidas envolvem a estimação de ângulos-de-chegada usando arranjos de antenas. Diante destas possibilidades, cresce em importância o estudo das variações do canal de propagação rádio móvel no domínio em que o uso dos arranjos de antenas atua: o espacial. O presente trabalho procura contribuir para o contexto em questão, com uma investigação experimental do canal real rádio-móvel nos domínios temporal (retardos) e espacial (ângulos-de-chegada). No que se refere ao contexto nacional, contribuições similares baseadas em simulações já são encontradas; baseadas em medidas não. Em particular, sondagens na faixa de 1,8 GHz em ambientes internos típicos foram realizadas. Duas técnicas distintas de sondagem temporalespacial foram implementadas, tomando por base uma sonda de canal faixa-larga montada e testada com sucesso, como contribuição principal de uma dissertação de mestrado recentemente apresentada por um integrante do mesmo grupo de pesquisa ao qual esta tese está vinculada. Uma das técnicas sintetiza o arranjo realizando as sondagens com uma única antena que é sucessivamente deslocada para ocupar as posições correspondentes às dos elementos do arranjo. A outra técnica emprega um arranjo real. Em ambas, a configuração mais simples para um arranjo foi utilizada: a linear uniforme. As sondagens não forneciam diretamente os espectros espaciais-temporais. As estimativas dos espectros foram processadas posteriormente, aplicando técnicas como o correlograma para o domínio do retardo, e quatro técnicas distintas para o domínio espacial, que foi o foco principal deste trabalho: duas convencionais; e duas paramétricas, com potencial de aumentar a resolução das estimativas, assumindo hipóteses razoáveis sobre as respostas esperadas. De posse das respostas espectrais estimadas, comparações com estimativas teóricas permitiram uma análise de desempenho das técnicas utilizadas. Adicionalmente à investigação experimental do canal espacial, procurou-se verificar o potencial da aplicação da teoria de wavelets ao estudo do canal rádiomóvel. Em especial, uma das principais aplicações daquela teoria foi testada como técnica de pós-processamento das respostas espectrais no domínio do retardo. A supressão de ruído por decomposição wavelet foi aplicada a um vasto conjunto de medidas de canal disponíveis, fruto de trabalhos anteriores do grupo de pesquisa ao qual esta tese está vinculada, com resultados expressivos.
In the present mobile communications scenario, researchers have turned once again special attention to antennae arrays, particularly when adaptive schemes are employed to modify its radiation patterns. One of its main applications results in considerable increases to the spectral efficiency of present and next generation mobile systems. The other major application is headed towards position location systems, since some of the known techniques comprise angle-of-arrival estimation using antennae arrays. Under such possibilities, mobile radio propagation channel variations studies grow in relevance, specially regarding the antennae arrays main domain of action: the spatial domain. The present work tries to contribute to the overstated context, experimentally investigating the actual mobile radio channel over the temporal (delays) and spatial (angles of arrival) domains. Regionally speaking, similar contributions based on simulations are already found, but none based on measurements. In special, 1.8 GHz indoor soundings have been carried out. Two different temporal spatial sounding techniques have been deployed, based on na available wideband channel sounder successfully assembled and tested as the major contribution of a MSc. dissertation recently presented by a member of the same research team to which this thesis belongs. One of such techniques sinthesyzes the array carrying the sounding out with a single antenna, which is successively moved to occupy the spots corresponding to the array elements. The other method employs an actual array. For both cases, the simplest array configuration has been used: the uniform linear one. Space-time spectra were not directly available in real time during the soundings. Its estimates have been processed later, applying techniques such as the correlogram over the delay domain, and four distinct methods over the spatial domain, the main focus of the present work. Two conventional methods have been used, as well as two parametric ones, potentially capable to increase the estimates resolution, assuming reasonable hypotheses regarding the expected responses. With the estimated spectral responses in hands, comparisons with theoretical estimates allowed a performance assessment of the employed methods. In addition to the spatial channel experimental investigation, the wavelets theory potential of application to the mobile-radio channel study has been checked out. Notably, one of the wavelets theory major applications has been tested as a post-processing technique to improve delay-domain spectral responses. Wavelet decomposition based de-noising has been applied to a huge measurements ensemble, available as the product of previous works of the research group to which this thesis is attached, leading to remarkable results.
5
Cocco, Helen. "Seamless shopping in omnichannel retailing : the effect of channel integration on consumers’ responses." Thesis, Lille 1, 2020. http://www.theses.fr/2020LIL1A010.
Full textAbstract:
L’évolution des comportements d’achat des consommateurs oblige les commerçants à offrir des expériences sans couture. Les consommateurs disposent maintenant d’une multitude de canaux d’achat qu’ils utilisent souvent simultanément tout au long des phases de recherche, d’achat et d’après-vente de l’expérience d’achat. Avec l’évolution des technologies mobiles qui favorise l’achat sur de multiples canaux, les consommateurs attendent désormais une expérience d’achat sans couture. Pour les commerçants, ces attentes représentent souvent des défis technologiques et opérationnels, dans la mesure où diverses complications peuvent apparaître lorsqu’il s’agit de relier des canaux, des terminaux et des points de contact avec la clientèle. Un manque d’intégration des canaux peut provoquer des interruptions et des désagréments, alors que des canaux bien intégrés génèrent des parcours d’achat cohérents, continus et ininterrompus qui favorisent un comportement positif des consommateurs. Ces défis ont conduit de nombreux commerçants à développer des stratégies omni-canaux, qui se concentrent sur la création d’expériences clients sans couture. Les sociétés rivalisent maintenant pour améliorer l’expérience client et, par conséquent, offrir un parcours d’achat sans couture n’a jamais été aussi pertinent. Cette thèse apporte une contribution au domaine émergent de la recherche sur l’expérience client en permettant de mieux comprendre comment et dans quelles conditions les consommateurs vivent une expérience d’achat fluide et sans friction. Premièrement, une conceptualisation du parcours d’achat sans couture apporte une clarté indispensable dans le cadre de la recherche et de la pratique, permet une utilisation plus précise et soutient la poursuite du développement théorique. Bien que la recherche existante montre l’importance du parcours d’achat sans couture en marketing, on ne sait pas vraiment ce que recouvre ce terme. Deuxièmement, sur la base de cette conceptualisation, une échelle de mesure comportant 7 items est établie pour faciliter sa mise en œuvre à la fois dans la littérature et dans la pratique. L’association de la conceptualisation et de l’établissement d’une échelle élargit la portée du concept et apporte une plus grande clarté. Troisièmement, au niveau théorique, nous développons un cadre qui fait le lien entre le parcours d’achat sans couture et les concepts de marketing reconnus. Cela répond à la demande accrue en matière de recherche sur les moteurs du parcours d’achat sans couture en définissant l’intégration des canaux comme moyen de créer un parcours d’achat sans couture. Le cadre élargit également la recherche en prévoyant plusieurs conséquences bénéfiques de l’achat sans couture. Ce cadre conceptuel est examiné de façon empirique dans l’environnement de commerce de détail d’un second pays, ce qui renforce l’impact de cette recherche dans un contexte international. Enfin, cette étude s’appuie sur des recherches antérieures en examinant les caractéristiques psychographiques des clients qui ont un impact sur la relation entre l’intégration des canaux et le parcours d’achat sans couture. Les résultats identifient les domaines où les commerçants devraient consacrer plus de temps et d’efforts aux initiatives d’intégration des canaux pour parvenir à des achats sans couture. Cette thèse jette un éclairage précieux sur le parcours d’achat sans couture dans le commerce de détail omni-canal et les résultats apportent des renseignements précieux, sur le plan universitaire et pratique, dans le domaine de l’expérience clientChanging consumer shopping behaviours are challenging retailers to deliver seamless experiences. Consumers now have a plethora of available shopping channels that they use, often simultaneously throughout the search, purchase and post-purchase phases of the shopping experience. With the evolution of mobile technology advancing multiple channel shopping, consumers now expect seamless shopping. For retailers, these expectations often represent technological and operational challenges, where several complications can exist in linking channels, devices and touchpoints. A lack of channel integration can cause disruption and inconvenience, whereas well integrated channels lead to consistent, continuous and uninterrupted shopping journeys that promote desirable consumer behavioural outcomes. These challenges have led many retailers to develop omnichannel strategies, which focus on creating seamless customer experiences. Companies now compete on customer experience and therefore, offering seamless shopping has never been so pertinent. This dissertation contributes to the emerging field of customer experience research by providing insightful understanding into what, how and under what conditions, consumers experience seamless shopping. Firstly, a conceptualization of seamless shopping provides much needed clarity for research and practice, ensures more accurate usage and supports further theoretical development. Although existing research indicates the importance of seamless shopping in marketing, there is little knowledge about what the term is comprised of, and its constituent parts. Secondly, based on this conceptualization, a 7-item measurement scale is established to aid its implementation both in literature and in practice. The partnering of conceptualization and scale development broadens the concept’s scope and adoption in practice. Thirdly, on a theoretical level, we develop a framework that links seamless shopping with established marketing constructs. This answers calls for more research on drivers of consumers’ seamless purchases by establishing channel integration as a means to creating seamless shopping. The framework also extends the research by predicting several beneficial consequences of seamless shopping. This conceptual framework is empirically examined or a second country retail environment, which strengthens the impact of this research in an international context. Finally, this study builds on previous research by examining customer psychographic characteristics that impact the channel integration-seamless shopping relationship. Results identify where retailers should allocate more time and effort into channel integration initiatives to achieve seamless shopping, and the corresponding desirable outcomes. This dissertation places a valuable lens on seamless shopping in omnichannel retailing and the findings provide valuable academic and practical insights in the customer experience field
6
Cho, Jung Rim. "Effect of Multichannel Retailers’ Cross-Channel Integration Practices on Consumers’ Affective and Behavioral Responses." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1351182773.
Full text
7
Kearns, Austin. "MECHANOSENSITIVE REGULATION OF INFLAMMATORY RESPONSES IN ASTROCYTES: AN UNDERLYING MECHANISM OF OPIOID-INDUCED HYPERALGESIA." OpenSIUC, 2021. https://opensiuc.lib.siu.edu/theses/2814.
Full textAbstract:
Opioids are gold-standard analgesics for pain relief in chronic pain conditions. Paradoxically, chronic opioid use causes an enhanced pain sensitivity termed ‘Opioid-induced hyperalgesia’ (OIH). OIH is a clinically relevant problem associated with the use of opioids. In addition to decreasing quality of life, increased pain from OIH necessitates increasing dosages of analgesics to effectively control the pain, resulting in an increased risk of opioid epidemics, addiction, and overdose. To prevent this clinically important effect, it is necessary to understand how chronic opioid use causes hyperalgesia. Our preliminary studies revealed that synaptic plasticity in the spinal dorsal horn (SDH) is dependent on neuron type in the OIH model and occurs concurrently with hyperalgesia, suggesting central sensitization as a mechanism of OIH. We found that astrocyte ablation blocked mechanical hyperalgesia and neuron type-dependent synaptic plasticity, indicating that astrocytes are critically involved in OIH. Additionally, morphine treatment upregulated IL-1β expression in the SDH in our preliminary experiments. Inhibition of IL-1β prevented OIH and blocked the repeated morphine-induced synaptic plasticity in the SDH, suggesting IL-1β is a key player in the pathogenesis of OIH. Astrocytes and other glial cells are critical in the development and maintenance of neuroinflammatory conditions, such as OIH, through the release of proinflammatory cytokines (PICs), including IL-1β. The mechanosensitive ion channel, Piezo1, was recently found to be upregulated in astrocytes and microglia under LPS-induced inflammatory conditions, and activation of Piezo1 was found to reduce IL-1β expression in LPS-inflamed primary mouse astrocytes. The goal of this study was to investigate the function of Piezo1 as a potential treatment for neuroinflammatory diseases of the CNS in a model of LPS-induced inflammation. In this study, we created a culture cell model of LPS-induced astrocytic neuroinflammation using the C8-S type II astrocyte culture cell line. We used a multi-disciplinary approach of electrophysiology and imaging to assess changes in calcium flux induced by the selective Piezo1 agonist, Yoda1, and mechanosensitive ion channel activity in the LPS-stimulated C8-S culture astrocytes. We found that calcium flux is increased in LPS stimulation and augmented by additional Yoda1 treatment. We also found that LPS stimulation increases mechanosensitive ion currents and stiffens cell membranes using patch-clamp electrophysiology techniques. These results indicate that Piezo1 is likely upregulated in the LPS model of cultured astrocytes, thus mechanosensitive responses are increased. Results from these experiments reveal key information about the mechanical properties of Piezo1 and poise Piezo1 as a promising therapeutic for OIH and other neuroinflammatory diseases caused by astrocytic IL-1β release.
8
Edwards, Bobbie. "The Effects of Tests and Praise on Children's Hear-write and See-say Responses." Thesis, University of North Texas, 2006. https://digital.library.unt.edu/ark:/67531/metadc5465/.
Full textAbstract:
Four elementary school children were tested on 120 words containing the short e (e.g., ten, pen) and short a (e.g., tan, pan) sounds. Words were tested in the hear-write (H/W) and see-say (S/S) channels. No programmed consequences were scheduled during baseline (BL) tests 1-3. After BL, an error analysis categorized words based on channel error and topography of error. Praise was delivered during tests 4-6 for correct responses. Children's responses were variable within channel and across channels for a majority of words. By the end of the praise phase, there was a decrease in the number of words with errors, for all children in their error word group. Error topographies began to stabilize for some words during praise.
9
Bill, Michael D. "Channel morphology and substrate responses to high flows and road construction in forested mid-Appalachian watersheds /." Available to subscribers only, 2005. http://proquest.umi.com/pqdweb?did=1079664441&sid=25&Fmt=2&clientId=1509&RQT=309&VName=PQD.
Full text
10
Flinn, Michael Brainerd. "Biological responses in off-channel habitat to hydrologic gradients and river management practices in Mississippi River Pool 25 /." Available to subscribers only, 2006. http://proquest.umi.com/pqdweb?did=1140187751&sid=18&Fmt=2&clientId=1509&RQT=309&VName=PQD.
Full text
11
Mclean, Matthew. "Functional responses of fish communities to environmental gradients in the North Sea, Eastern English Channel, and Bay of Somme." Thesis, Littoral, 2019. http://www.theses.fr/2019DUNK0532/document.
Full textAbstract:
Il est essentiel de décrire la dynamique spatiale et temporelle des communautés de poissons pour comprendre le fonctionnement et les services des écosystèmes marins. Cette thèse a utilisé des données de surveillance scientifique à long terme pour caractériser les réponses fonctionnelles des communautés de poissons aux gradients environnementaux en baie de Somme, Manche orientale et mer du Nord. Les trois écosystèmes ont connu des hausses de température associées à une phase de réchauffement de l'oscillation multidécennale de l'Atlantique, ce qui a eu des impacts rapides sur la structure des communautés. Dans les trois écosystèmes, les réponses des communautés ont été médiées par des traits associés à l’habitat et à l’histoire de vie. Dans la mer du Nord et la Manche Est, les espèces pélagiques étaient les plus sensibles, ce qui s'explique probablement par leur mobilité et leur dispersion plus élevés. Cependant, au-delà de l'habitat, les espèces à stratégie démographique r (faible taille et âge à maturité, faible investissement parental, etc.) ont eu des réponses environnementales plus rapides. La pression historique de la pêche semble d’avoir rendu les communautés plus sensibles aux changements environnementaux en augmentant l'abondance relative des espèces pélagiques et à stratégie r. De plus, comme ces écosystèmes se sont réchauffés au cours des 30 dernières années, les réponses des communautés ont été caractérisées par une augmentation de la préférence thermique moyenne, ce qui suggère que le réchauffement climatique favorisera des espèces mieux adaptées aux conditions chaudes et que les espèces ayant des cycles de vie rapides seront les premières à répondreThe ensemble of biological, geochemical, and physical processes that occur within ecosystems is driven by the interplay between biological communities and the abiotic environment. Explaining the spatial and temporal dynamics of biological communities in relation to environmental conditions is therefore essential for understanding ecosystem functioning, and ultimately for achieving sustainable development. In marine ecosystems, fish communities are key to ecosystem functioning, and fisheries provide livelihoods for over 10% of the world’s population. However, understanding the processes structuring fish communities remains difficult because community structure varies with both natural environmental fluctuations and, increasingly, human pressures. Effectively managing fisheries and marine ecosystems under global change therefore requires better characterizing fish community dynamics over time and space and disentangling the underlying drivers and mechanisms. While fish ecologists have traditionally relied on species-based approaches (i.e., taxonomic approaches) to study community structure, trait-based approaches (i.e., functional approaches) are increasingly used because they can provide better insight into community assembly and the mechanisms driving community responses. To meet this need for a better understanding of biodiversity dynamics, the present thesis took advantage of long-term scientific monitoring data to characterize the functional responses of fish communities to environmental gradients in the North Sea, Eastern English Channel, and Bay of Somme. All three ecosystems experienced temperature rises and oceanographic changes associated with a warming phase of the Atlantic Multidecadal Oscillation (AMO), which rapidly impacted fish community structure. Consistent biological responses were observed across the three ecosystems despite their different spatial scales, demonstrating that fish communities were affected by environmental change through bio-ecological traits associated with habitat preference and life history. In the North Sea and Eastern Channel, pelagic species were the most responsive and contributed largely to community dynamics, which is likely explained by their greater mobility, higher dispersal rates, and fewer habitat requirements. However, beyond habitat preference, species with r-selected life histories (e.g., low size and age at maturity, low parental investment, small offspring) had the fastest environmental responses whether or not they were pelagic, likely due to their rapid population turnover and generation time. Importantly, the way these species’ responses shaped community structure depended on environmental context. R-selected, pelagic species rapidly declined in the Bay of Somme and Eastern Channel, but rapidly increased in the North Sea. This likely reflects environmental suitability, indicating that after the phase change of the AMO, the Eastern Channel became a less favorable environment for these species, while the North Sea became more favorable. Thus, species with high mobility and fast life history cycles appear capable of rapidly tracking environmental conditions, shifting in abundance in response to environmental suitability. Additionally, as these ecosystems have warmed over the last 30 years, community responses were characterized by increases in mean thermal preference. Importantly, the amplitude of community changes was partially determined by communities’ initial structure and redundancy of bio-ecological traits, showing that community responses depended not only on environmental changes but also on biodiversity itself. Lastly, while fish community responses were consistently associated with climatic changes, historical fishing pressure on large-bodied, demersal species appeared to render fish communities more sensitive to environmental changes by increasing the relative of abundance of pelagic and r-selected species
12
OCK, Giyoung. "PARTICULATE ORGANIC MATTER DYNAMICS IN THE DOWNSTREAM OF DAM RESERVOIRS: ROLES OF CHANNEL GEOMORPHOLOGY AND RESPONSES OF BENTHOS COMMUNITIES." 京都大学 (Kyoto University), 2010. http://hdl.handle.net/2433/120804.
Full text
13
Harendza, Astrid. "Benthic habitats in a tide-swept channel of the Pentland Firth and their potential responses to a tidal energy development." Thesis, University of the Highlands and Islands, 2014. https://pure.uhi.ac.uk/portal/en/studentthesis/benthic-habitats-in-a-tideswept-channel-of-the-pentland-firth-and-their-potential-responses-to-a-tidal-energy-development(f5af15f2-779a-4fa1-9ab9-467d8aa1cb2d).html.
Full textAbstract:
This thesis investigates sublittoral epibenthic assemblages, the ecological processes associated with distributions of benthic assemblages and potential ecological impacts arising from the de-ployment of tidal energy devices (TEDs) at a key tidal energy development site. An extensive field campaign was undertaken to collect fine-scale, in-situ data for local hydrodynamics, seabed structure and epibenthic assemblages. Data from a two-dimensional hydrodynamic model com- plemented in-situ flow data and provided an insight into possible changes to local tidal patterns after the deployment of a tidal array. The study revealed a highly complex tidal stream structure with maximal velocities reaching 4.2 ms1 during spring tide. The seabed was predominantly formed by scoured bedrock. Deployment of a tidal array was predicted to decrease tidal flow within and downstream of the array by up to 24 % for peak flows, whereas effects on the seabed were thought to be minor. Epibenthic assemblages were typical for tide-swept channels with a fringe of dense kelp forest along the shallow, sheltered waters of the channel, followed by a 'tran- sition zone' dominated by foliose red algae in the mid-depth ranges and animal turf assemblages in the deeper, very tide-swept waters. Multivariate analyses identified depth and bed-shear stress as being strongly associated with the distribution and composition of assemblages. In conjunction with presence-only data for epibenthic species, depth and bed-shear stress were used as predic- tor variables to develop site-specific habitat suitability models (HSMs) for a baseline and TED deployment case. Comparison of probability of occurrence values between the respective HSMs indicated a potential increase of suitable habitat for species inhabiting the deep, very tide-swept circalittoral following the deployment of TEDs, whilst assemblages along the fringes of the channel were mostly unaffected. This is the first attempt of using HSM as a tool for identification of potential changes in distributions of benthic species arising from the deployment of TEDs. The good overall performance of the models shows this tool may be valuable for for impact analysis of tidal energy development projects.
14
McHarg, A. D. "The effect of endothelial removal on the contractile responses of canine coronary arteries and their inhibition by the calcium channel inhibitors." Thesis, University of Strathclyde, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382305.
Full text
15
Warman, Craig S. "Understanding the spatial and temporal variation in anthropogenically induced channel response in the Irwin River catchment." University of Western Australia. School of Earth and Geographical Sciences, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0214.
Full textAbstract:
The Irwin River catchment, located in the central western region of Western Australia, has been the scene of significant geomorphological change over both historical and geological timescales. This thesis focuses on the most recent of these changes, the anthropogenic imprint, through the development of a catchment-scale understanding of system behaviour. Analysis and modelling of changes in the hydrological behaviour of the system indicates that while the Irwin River has displayed a natural susceptibility to large flood events, these have been exacerbated by the widespread clearing of native vegetation throughout the catchment. As a result, when such events do occur, the catchment response is now larger, more direct and has a greater ability to cause erosion. However, the nature and detail of sediment yield processes and stream channel response varies markedly throughout the system. A series of representative channel reaches, as defined by their planform characteristics, geometry and architecture, are presented to illustrate spatial changes in stream channel behaviour. A distinct variation in river morphotypes is seen both downstream throughout the system as well as across the tributary sub-catchments of the Irwin River, Lockier River and Green Brook. This inter and intra sub-catchment variation in stream channel response can be attributed to changes in the boundary conditions and coupling mechanisms in operation throughout the Irwin River system. The pronounced spatial variability in response to human disturbance and the changing nature of catchment-scale connectivity seen in the Irwin River system differs markedly to that reported elsewhere in the literature. Appreciation of the variability in form, behaviour and evolutionary history throughout the Irwin River catchment not only provides the foundation for effective management but also contributes to a wider understanding of fluvial system behaviour. Unlike the majority of existing literature, which tends to identify and measure channel changes in a single catchment where historical variation to the sediment and discharge regime is well known, this study demonstrates the role of boundary conditions in determining the response of the fluvial system to changing environmental controls.
16
Leary, James Christian. "Northsealand : a study of the effects, perceptions of, and responses to, Mesolithic sea-level rise in the southern North Sea and Channel/Manche." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/northsealand-a-study-of-the-effects-perceptions-of-and-responses-to-mesolithic-sealevel-rise-in-the-southern-north-sea-and-channelmanche(c920012d-bfab-4a6f-905c-6621f8b850c7).html.
Full textAbstract:
This study identifies and critically assesses the social and physical consequences of, and possible responses to, sea-level rise and loss of land in the area that is now covered by the southern North Sea and English Channel/La Manche during the Mesolithic period. It suggests that Mesolithic studies still, despite debate on the matter, frame hunter fisher gatherers in economic terms. In this way, nature is seen as a separate entity to culture, the changing environment, therefore, becomes an external force against which people struggle. However, as an alternative, this thesis advocates an understanding of Mesolithic hunter fisher gatherers as an integral part of their changing world, suggesting that they would have had a fundamental awareness of these changes through a sensorial engagement, and acted accordingly. That said, it also suggests that, while not all people living in the area were equally affected by sea-level rise, the associated loss of land could have profoundly impacted people’s sense of place and being. It also highlights that, although sea-level rise and climate change occurred globally and on a millennial-scale, it unfolded and was experienced at a local and generational level. It therefore makes a case that to understand the human experience of early Holocene sea-level rise, it must be studied at the local-scale. This provides us with a better understanding of the effects of sea-level rise – a sense of the experience of it, rather than simply recording it as an abstract concept. Further, the local scale can identify problems that are not necessarily obvious from the larger scale. In this way, this thesis captures some of the nuances of environmental change that are frequently missing from the archaeological literature, and highlights the intense relationship between humans and their environment, providing a fresh approach to Mesolithic environment relations and a richer and more complex story of the effects of early Holocene sea-level rise.
17
Croy, Ilona, Kerstin Laqua, Frank Süß, Peter Joraschky, Tjalf Ziemssen, and Thomas Hummel. "The sensory channel of presentation alters subjective ratings and autonomic responses toward disgusting stimuli – Blood pressure, heart rate and skin conductance in response to visual, auditory, haptic and olfactory presented disgusting stimuli." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-127292.
Full textAbstract:
Disgust causes specific reaction patterns, observable in mimic responses and body reactions. Most research on disgust deals with visual stimuli. However, pictures may cause another disgust experience than sounds, odors, or tactile stimuli. Therefore, disgust experience evoked by four different sensory channels was compared. A total of 119 participants received 3 different disgusting and one control stimulus, each presented through the visual, auditory, tactile, and olfactory channel. Ratings of evoked disgust as well as responses of the autonomic nervous system (heart rate, skin conductance level, systolic blood pressure) were recorded and the effect of stimulus labeling and of repeated presentation was analyzed. Ratings suggested that disgust could be evoked through all senses; they were highest for visual stimuli. However, autonomic reaction toward disgusting stimuli differed according to the channel of presentation. In contrast to the other, olfactory disgust stimuli provoked a strong decrease of systolic blood pressure. Additionally, labeling enhanced disgust ratings and autonomic reaction for olfactory and tactile, but not for visual and auditory stimuli. Repeated presentation indicated that participant's disgust rating diminishes to all but olfactory disgust stimuli. Taken together we argue that the sensory channel through which a disgust reaction is evoked matters.
18
Croy, Ilona, Kerstin Laqua, Frank Süß, Peter Joraschky, Tjalf Ziemssen, and Thomas Hummel. "The sensory channel of presentation alters subjective ratings and autonomic responses toward disgusting stimuli – Blood pressure, heart rate and skin conductance in response to visual, auditory, haptic and olfactory presented disgusting stimuli." Frontiers, 2013. https://tud.qucosa.de/id/qucosa%3A27294.
Full textAbstract:
Disgust causes specific reaction patterns, observable in mimic responses and body reactions. Most research on disgust deals with visual stimuli. However, pictures may cause another disgust experience than sounds, odors, or tactile stimuli. Therefore, disgust experience evoked by four different sensory channels was compared. A total of 119 participants received 3 different disgusting and one control stimulus, each presented through the visual, auditory, tactile, and olfactory channel. Ratings of evoked disgust as well as responses of the autonomic nervous system (heart rate, skin conductance level, systolic blood pressure) were recorded and the effect of stimulus labeling and of repeated presentation was analyzed. Ratings suggested that disgust could be evoked through all senses; they were highest for visual stimuli. However, autonomic reaction toward disgusting stimuli differed according to the channel of presentation. In contrast to the other, olfactory disgust stimuli provoked a strong decrease of systolic blood pressure. Additionally, labeling enhanced disgust ratings and autonomic reaction for olfactory and tactile, but not for visual and auditory stimuli. Repeated presentation indicated that participant's disgust rating diminishes to all but olfactory disgust stimuli. Taken together we argue that the sensory channel through which a disgust reaction is evoked matters.
19
Olah, Mark E. "Effects of calcium channel blockade and intracellular calcium antagonism on endothelium-dependent responses of the isolated rat aorta and influence of the endothelium on drug action /." The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487590702989006.
Full text
20
Fouty, Suzanne Catherine. "Current and historic stream channel response to changes in cattle and elk grazing pressure and beaver activity." Thesis, view abstract or download file of text, 2003. http://wwwlib.umi.com/cr/uoregon/fullcit?p3080584.
Full textAbstract:
Thesis (Ph. D.)--University of Oregon, 2003.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 634-646). Also available for download via the World Wide Web; free to University of Oregon users.
21
Ellis, Lee David. "Potassium channel control of neuronal frequency response." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103381.
Full textAbstract:
The processing of sensory signals is an important, yet complex task in which a system must extract behaviorally relevant stimulus patterns from a vast array of sensory cues. When a neuron within a major sensory area is presented with a stimulus, one of the important characteristics used to distinguish between types of input is frequency. Often sensory neurons are tuned to narrow stimulus frequency ranges and are thus charged with the processing of subtypes of sensory signals. The weakly electric fish Apteronotus lepthorhynchus senses it's environment through modulations of a self-generated electric field. Two main types of sensory signals can be distinguished based on their frequency patterns. Prey stimuli cause low frequency perturbations of the electric field, while communication signals often result in high frequency signals. Pyramidal neurons in the electrosensory lateral line lobe (ELL) encode the low frequency signals with bursts, while the high frequency signals are relayed with single spikes. This thesis describes how a pyramidal neuron's response patterns can be tuned to specific frequencies by the expression of distinct classes of potassium channels.I have cloned 3 small conductance (SK) calcium activated potassium channels from cDNA libraries created from the brain of Apteronotus. I have subsequently localized the AptSK channels throughout the brain using both in situ hybridization (AptSK1, 2 & 3) and immunohistochemical (AptSK1 & 2) techniques. The 3 channels showed distinct expression patterns, with the AptSK1 & 2 channels showing a partially overlapping expression pattern, while AptSK3 appears to be expressed in unique areas of the brain. In the ELL AptSK1 & 2 show a partially overlapping expression pattern, appearing in similar pyramidal neurons. However, their distribution within individual cell is unique, with AptSK1 showing a dendritic localization, while AptSK2 is primarily somatic. We have demonstrated that the unique expression pattern of the somatic AptSK2 channel in the ELL coincides with the functional SK currents evaluated through in vitro electrophysiology. Further we have shown that neurons that encode low frequencies do not possess functional SK channels. It thus appears that the presence of the AptSK2 channel subtype can predispose a neuron to respond to specific types of sensory signals.
In an attempt to evaluate if second messengers could modify the AptSK control of frequency tuning I investigated the consequences of muscarinic acetylcholine receptor (mAChR) activation on a pyramidal neurons response patterns. While it had been shown in vivo that mAChR activation increased a pyramidal neuron's response to low frequencies, I have found that this was not due to a decrease in AptSK current, but rather appears to be the result of a down-regulation of an A-type potassium channel.
Taken together the studies that comprise this thesis show how the selective expression of a single potassium channel subtype can control a sensory neurons response to specific environmental cues. The secondary modulation of the A-type current highlights the potential for a second messenger to control a neuron's sensory response through the down-regulation of constitutively expressed potassium current.
22
Li, Wenhua. "Channel response and target detection in shallow water." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/42573.
Full text
23
Rudd, Richard. "Statistical prediction of indoor radio channel impulse response." Thesis, University of Surrey, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486097.
Full textAbstract:
The characterisation of the indoor radio channel has been an active area of research in the last decades, and this is likely to continue with the increasing importance of wireless techniques for the provision of connectivity within homes and offices. This thesis gives a survey of existing models for the indoor radio channel, noting that sitespecific predictions are often of limited use owing to the difficulty of determining accurate details ofthe indoor environment. While ray tracing models, for instance, are potentially capable of offering highly accur~te prediction, this promise is seldom fulfilled in practice owing to the difficulty of capturing the necessary input data for such models. As a consequence, statistical treatments ofthe indoor channel are popular, and two such models for the temporal response ofthe wideband channel are discussed in some detail. These models, however, rely on the use of empirical parameters that will either represent only the generality of buildings, or will need to be determined by measurement for each specific case. An alternative model was therefore sought which combined physical and statistical elements to introduce a greater degree of site-specificity. The initial modelling reported in this thesis took, as its basis, the methods developed within the acoustic community for the prediction of impulse response within reverberant rooms. The thesis then proposes a new model for the prediction ofthe average power delay profile (PDP) within a room, taking the extreme room dimensions as parameters to allow the accommodation of site-specific detail. A measurement campaign, using a channel sounder developed for the purpose, is described, and the results compared with the predictions offered by the new model. Finally, the thesis suggests ways in which the new model might be used as a component of other, more general, models for the indoor radio channel.
24
Souvignier, Thomas Victor. "Turbo decoding for partial response channels /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1999. http://wwwlib.umi.com/cr/ucsd/fullcit?p9938584.
Full text
25
McEwen, Peter A. "Trellis coding for partial response channels /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1999. http://wwwlib.umi.com/cr/ucsd/fullcit?p9968170.
Full text
26
Yeap, Bee Leong. "Turbo equalisation algorithms for full and partial response modulation." Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310853.
Full text
27
Snyder, Noah P. "Bedrock channel response to tetonic, climatic and eustatic forcings." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8254.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2001.Includes bibliographical references.
The response of bedrock channels to external forcings is investigated in this thesis. The approach is to test and constrain a theoretical model for bedrock-channel incision based on shear stress using field data. The primary study area is a series of 21 small, coastal drainage basins in northern California, USA with known, varying rates and history of rock uplift. The initial application of a simple form of the model to the stream profiles suggests that (1) the channels are eroding at rates approximately equal to uplift rates (i.e. steady-state fluvial incision), and (2) erosion processes are proportionally more effective in the high-uplift-rate zone, with factors in addition to channel gradient responding to tectonic forcing. These results lead to the rest of the study, in which some of the assumptions of the simple model are rejected in order to explain the second observation. A more sophisticated model that includes both a stochastic distribution of floods and a threshold shear stress to initiate bedrock erosion predicts that a greater part of the distribution of flood events will exceed the threshold in steeper channels. Therefore, higher-gradient channels have proportionally higher erosion rates, as is observed in the high-uplift-rate streams of the California field site. The shear-stress model is tested and constrained through a detailed, field-based analysis of topography, lithology, stream morphology and regional hydrology to isolate those factors that respond to tectonics. The stochastic model is able to incorporate the observed variation in stream discharge due to orographic enhancement of precipitation by high topography associated with high uplift rates.
(cont.) This increase in discharge appears to play a second-order role in setting the erosional effectiveness of the high-uplift zone. Other factors, including channel width, lithologic resistance and sediment flux, do not appear to vary in an important way with uplift rate, although this conclusion is based on analyses that have some limitations. The importance of thresholds is underscored by a direct calculation of critical shear stress during a rare bedrock-incision event in a low-erosion-rate creek in New York state (= 100-200 Pa). This event, the only one that caused significant bedrock plucking at the site in an -40-year period, is consistent with a low erosion rate, with few events that exceed the threshold. In contrast, similar 'z values are exceeded during high-frequency flood events in the steep, rapidly eroding California streams. Inclusion of an erosion threshold accounts for the observed relationship between channel gradient and rock-uplift rate in the California site. In summary, by using field examples, the shear-stress bedrock-incision model with a stochastic distribution of flood events and an erosion threshold is demonstrated to be an effective and powerful tool for exploring relationships amongst climatic, tectonic and surficial processes. In the final section of this thesis, a numerical modeling study couples the shear-stress model for onshore fluvial incision with a simple rule for offshore wave-based erosion of bedrock to explore the response of uplifting streams to eustatic fluctuations ...
by Noah P. Snyder.
Ph.D.
28
McGuinness, James. "Implications of potassium channel heterogeneity for model vestibulo-ocular reflex response fidelity." Thesis, University of Stirling, 2014. http://hdl.handle.net/1893/21844.
Full textAbstract:
The Vestibulo-Ocular Reflex (VOR) produces compensatory eye movements in response to head and body rotations movements, over a wide range of frequencies and in a variety of dimensions. The individual components of the VOR are separated into parallel pathways, each dealing with rotations or movements in individual planes or axes. The Horizontal VOR (hVOR) compensates for eye movements in the Horizontal plane, and comprises a linear and non-linear pathway. The linear pathway of the hVOR provides fast and accurate compensation for rotations, the response being produced through 3-neuron arc, producing a direct translation of detected head velocity to compensatory eye velocity. However, single neurons involved in the middle stage of this 3-neuron arc cannot account for the wide frequency over which the reflex compensates, and the response is produced through the population response of the Medial Vestibular Nucleus (MVN) neurons involved. Population Heterogeneity likely plays a role in the production of high fidelity population response, especially for high frequency rotations. Here we present evidence that, in populations of bio-physical compartmental models of the MVN neurons involved, Heterogeneity across the population, in the form of diverse spontaneous firing rates, improves the response fidelity of the population over Homogeneous populations. Further, we show that the specific intrinsic membrane properties that give rise to this Heterogeneity may be the diversity of certain slow voltage activated Potassium conductances of the neurons. We show that Heterogeneous populations perform significantly better than Homogeneous populations, for a wide range of input amplitudes and frequencies, producing a much higher fidelity response. We propose that variance of Potassium conductances provides a plausible biological means by which Heterogeneity arises, and that the Heterogeneity plays an important functional role in MVN neuron population responses. We discuss our findings in relation to the specific mechanism of Desynchronisation through which the benfits of Heterogeneity may arise, and place those findings in the context of previous work on Heterogeneity both in general neural processing, and the VOR in particular. Interesting findings regarding the emergence of phase leads are also discussed, as well as suggestions for future work, looking further at Heterogeneity of MVN neuron populations.
29
Chesnutt, Elizabeth. "Novel Turbo Equalization Methods for the Magnetic Recording Channel." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6867.
Full textAbstract:
Novel Turbo Equalization Methods for the Magnetic Recording Channel
Elizabeth Chesnutt
95 Pages
Directed by Dr. John R. Barry
The topic of this dissertation is the derivation, development, and evaluation of novel turbo equalization techniques that address the colored noise problem on the magnetic recording channel. One new algorithm presented is the noise-predictive BCJR, which is a soft-output detection strategy that mitigates colored noise in partial-response equalized magnetic recording channels. This algorithm can be viewed as a combination of the traditional BCJR algorithm with the notion of survivors and noise prediction.
Additionally, an alternative equalization architecture for magnetic recording is presented that addresses the shortcomings of the PRML approach, which dominates magnetic recording. Specifically, trellis-based equalizers are abandoned in favor of simple equalization strategies based on nonlinear filters whose complexity grows only linearly with their length. This research focuses on the linear-complexity SFE algorithm and on investigating the possibility of lowering the SFE filter calculation complexity. The results indicate that with using the proposed novel SFE method, it is possible to increase the information density on magnetic media without raising the complexity. The most important result presented is that partial-response equalization needs to be reconsidered because of the amount of noise enhancement problems that it adds to the overall system. These results are important for the magnetic recording industry, which is trying to attain a 1 Tb/cm2 information storage goal.
30
Springate, David. "Plastic and genetic responses to environmental changes." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/plastic-and-genetic-responses-to-environmental-changes(df87fd0e-c8a5-43ad-81d4-e0b0a1e25b44).html.
Full textAbstract:
Human activity is causing climates to change more rapidly than at any time in the last 10,000 years. If populations of organisms are unable to effectively respond to changing environments, they will be at risk of extinction. In plants, two of the most important mechanisms of response to environmental change are phenotypic plasticity, where the same genotype expresses different phenotypes in different environments, and adaptation, which requires changes in allele frequency in populations as exposed individuals show variable survival and reproduction. Although most researchers accept the importance of both of these mechanisms, they are most commonly considered in isolation in models of response and persistence to climate change. Here, I use the model species Arabidopsis thaliana to investigate the interaction of plasticity and selection in fitness and phenology response to simulated climate warming, the effect of artificial selection on variation for plastic response and cross-generational effects of environmentally induced variation in flowering time. I also study the effects of varying rates of environmental fluctuation on evolvability on populations of self-replicating computer programs using the artificial life platform Avida. I find that a small increase in ambient temperature, in line with predictions for the next few decades, is able to elicit significant plastic responses and that these responses have the potential to alter population genetic structure and affect future evolution. I also find that selection on flowering time can reduce variation for plastic response and that non-genetic effects on flowering time can significantly alter germination in the next generation. Lastly, I find that rapidly changing environments in the long term can select for more evolvable populations and genotypes. These results highlight the importance of considering plasticity and evolution together if we are going to make accurate predictions of climate change response.
31
Vargas, Rodriguez Carlos. "Ion channel remodeling in response to variations in heart rate." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97057.
Full textAbstract:
A downregulation of the transient outward K+ current (Ito) is a common finding in hypertrophy; tachypacing induced heart failure, which can lead to lethal arrhythmias and sudden death as a result of action potential prolongation.To better understand how variations in heart rate may affect the electrical properties of the heart, based on an in vitro tachypacing model, we compared frequency-dependent changes in adult epicardial (Epi) versus endocardial (Endo) canine cells. Thus, Ito was recorded with whole-cell patch-clamp in Endo and Epi cardiomyocytes after 24-hr culture under continuous electrical stimulation at either 1-Hz (normal rate) or 3-Hz (tachycardia). Ca2+ transient amplitudes (Indo1-AM) were recorded from En-do and Epi cells at 0hr, 2hr, 4hr, 8hr and 24hr after continuous electrical stimulation at either 1-Hz or 3-Hz. Analysis of inactivation/reactivation kinetics, activation/inactivation voltage dependence properties showed no difference between 1- and 3-Hz paced cells for either cell type. Tachypacing (3Hz pacing) reduced Ito density and Kv4.3 mRNA ex-pression in Epi cells but not in Endo. Ca2+-chelation by BAPTA-AM, prevented rate-dependent Ito downregulation in Epi cells, increasing Ito in tachypaced cells by ~47%. In Endo cells, BAPTA-AM increased Ito by ~200% in a rate-independent way. Con-sistent with the larger Endo response to Ca2+-chelation, Ca2+ transient amplitudes were greater in Endo (85±4 nM) than Epi (46±2 nM) cells. Ca2+ transient amplitude increased at early stages of tachypacing in Epi cells (i.e. 64.2±4.2 from 40.7±3.5 nM), in contrast to Endo cells. Inhibition of the calcineurin/NFAT pathway prevented rate-dependent Ito decrease in tachypaced Epi cells, without affecting Endo Ito.Our findings show that fast firing rate induces a different response in the regulation of Ito in adult Epi and Endo cells, which might be related to differential control by calcium-dependent signaling systems.Il est admit que le courant potassique sortant Ito est diminué de façon importante dans l'insuffisance cardiaque induite par un contexte d'hypertrophie ventriculaire et de tachystimulation. Plus précisément, des travaux précédents de notre laboratoire montrent que l'insuffisance cardiaque induite par tachystimulation ventriculaire chez le chien favorise les arythmies ventriculaires létales et la mort subite. Une réduction du courant Ito dans les ventricules a été démontrée dans ce modèle. Afin de mieux comprendre comment la tachystimulation (tachycardie ventricu-laire soutenue) affecte les propriétés électriques des cardiomyocytes ventriculaires, nous avons comparé l'effet de la tachystimulation in vitro sur le courant potassique Ito de cardiomyocytes de l'épicarde et de l'endocarde ventriculaire de chien. Le courant Ito de cardiomyocytes de l'epicarde et de l'endocarde à été enregistré à l'aide de la technique de patch-clamp en configuration cellule entière après 24h de culture sous tachystimulation continue a 1-Hz (rythme normal) ou 3-Hz (tachycardie). Les transi-toires calciques ont été étudiés (Indo1-AM) après 0, 2, 4, 8 et 24hr de stimulation a 1-Hz ou 3-Hz. L'analyse de la dépendance au voltage des processus d'inactivation et de réactivation du courant Ito n'a démontré aucune différence entre les cellules de l'épicarde et de l'endocarde, ni même entre 1-Hz et 3-Hz. De façon intéressante, la tachystimulation (3-Hz) réduisait la densité du courant Ito et l'expression des ARNms codant pour le canal Kv4.3 dans les cellules de l'épicarde mais pas dans l'endocarde. La chélation du calcium intracellulaire à l'aide du BAPTA-AM, prévenait cette diminution de Ito dans les cellules de l'épicarde entrainant une augmentation de ~47% du courant. Dans les cellules de l'endocarde, le BAPTA-AM provoquait une augmentation de ~200%. De façon cohérente avec une sensibilité des cellules de l'endocarde plus importante à la chélation de calcium, l'amplitude des transitoires calciques était plus importante dans les cellules de l'endocarde (85±4 nM) que dans les cellules de l'épicarde (46±2 nM). Alors que l'amplitude des transitoires calciques n'était pas modifiée par la tachystimulation dans les cellules de l'endocarde, une augmentation précoce était me-surée dans les cellules de l'épicarde (i.e. 64.2±4.2 vs 40.7±3.5 nM). L'inhibition de la voie de signalisation NFAT/calcineurine prévenait la diminution d' Ito dans les cellules de l'épicarde soumises à la tachystimulation et restait sans effet sur le courant Ito des cellules de l'endocarde.Nos résultats montrent que les cellules adultes de l'épicarde et de l'endocarde répondent de façon différente suite à une tachystimulation. Ce processus est possiblement lié à un contrôle différentiel de la signalisation induite par le calcium.
32
Kumar, Deepak. "Optimal finite alphabet sources over partial response channels." Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/1044.
Full textAbstract:
We present a serially concatenated coding scheme for partial response channels. The encoder consists of an outer irregular LDPC code and an inner matched spectrum trellis code. These codes are shown to offer considerable improvement over the i.i.d. capacity (> 1 dB) of the channel for low rates (approximately 0.1 bits per channel use). We also present a qualitative argument on the optimality of these codes for low rates. We also formulate a performance index for such codes to predict their performance for low rates. The results have been verified via simulations for the (1-D)/sqrt(2) and the (1-D+0.8D^2)/sqrt(2.64) channels. The structure of the encoding/decoding scheme is considerably simpler than the existing scheme to maximize the information rate of encoders over partial response channels.
33
Dorfman, Vladimir. "Detection and coding techniques for partial response channels /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2003. http://wwwlib.umi.com/cr/ucsd/fullcit?p3094619.
Full text
34
Fletcher, Julie Maxine. "Response of periodontopathogens to environmental changes." Thesis, University College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322503.
Full text
35
Fang, Song. "Channel Camouflage and Manipulation Techniques in Wireless Networks." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7284.
Full textAbstract:
The security of wireless networks and systems is becoming increasingly important as wireless devices are more and more ubiquitous nowadays. The wireless channel exhibits the spatial uncorrelation property, which is that the characteristics of a wireless channel become uncorrelated every half carrier wavelength over distance. This property has prompted an emerging research area that utilizes wireless channel characteristics to achieve location distinction, to detect location changes or facilitate authentication of wireless users, and to establish shared secret key between legitimate communicators. This dissertation includes two work toward the security improvement of existing wireless networks and systems. With the discovered channel camouflage and manipulation techniques in wireless networks, traditional wireless channel based authentication or secure communication systems are broke or renovated.
The first work proposes a new attack against all existing location distinction approaches that are built on this spatial uncorrelation property. With the discovered attack, an attacker can easily bypass authentication or camouflage location changes by creating an artificial wireless channel similar to a legitimate one. This dissertation also presents a detection technique that utilizes an auxiliary receiver or antenna to identify these fake channels.
On the other hand, the second work shows that the legitimate users can also benefit from constructing these artificial wireless channels and apply them in a novel wireless key establishment. The proposed technique enables the transmitter to specify any content as the secret key and securely deliver it to the target receiver, and meanwhile removes the reconciliation process which is necessary for conventional wireless key establishment schemes.
36
Eriksson, Rickard. "Price responses to changes in costs and demand." Doctoral thesis, Stockholm : Economic Research Institute, Stockholm School of Economics (Ekonomiska forskningsinstitutet vid Handelshögsk.) (EFI), 2001. http://www.hhs.se/efi/summary/554.htm.
Full text
37
Eaton, Brett. "Morphologic channel response to flood events in a salmon spawning stream." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21545.
Full textAbstract:
Changes in channel morphology in response to two flood events were measured within three reaches on the Sainte Marguerite River, Quebec. The first event was the spring freshet---peaking in mid-May, 1996---while the second event---peaking on July 20, 1996---was the largest flood on record for the region. The resultant channel adjustments can be classified as either bedform evolution---in which a clear, systematic pattern of adjustment is evident---or as bedform change, in which local hydraulic and sedimen tologic conditions produce a seemingly random pattern of channel mobilization. Where bedform evolution has occurred, it is consistent with the existing paradigm for meander development. Sediment transport calculations based on the 'inverse' or 'morphologic' method were strongly correlated to reach average mobility ratios. The average rate of transport in response to the larger flood approached those reported by others for a braided system (Goff and Ashmore, 1994). Potential spawning zones within the three reaches were all subjected to significant net scour and/or fill following the second event; several potential spawning zones were significantly affected by the first event The presence of bank protection upstream of a potential spawning zone seems to be a determinant 10 the severity of the impact by promoting erosion of these zones.
38
Eaton, Brett. "Morphologic channel response to flood events in a salmon spawning stream." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0027/MQ50760.pdf.
Full text
39
Darragh, Neil. "An adaptive partial response data channel for hard disk magnetic recording." Thesis, University of Plymouth, 1994. http://hdl.handle.net/10026.1/2594.
Full textAbstract:
An adaptive data channel is proposed which is better able to deal with the variations in performance typically found in the recording components of a hard disk drive. Three such categories of variation were investigated in order to gain an understanding of their relative and absolute significance; variations over radius, along the track length, and between different head / media pairs. The variations were characterised in terms of their effects on the step-response pulse width and signal-to-noise ratio. It was found that in each of the categories investigated, significant variations could be found in both longitudinal and perpendicular recording systems which, with the exception of radial variations, were nondeterministic over different head / media pairs but were deterministic for any particular head / media pair characterised. Conventional data channel design assumes such variations are non-deterministic and is therefore designed to provide the minimum error rate performance for the worst case expected recording performance within the range of accepted manufacturing tolerance. The proposed adaptive channel works on the principle that once a particular set of recording components are assembled into the disk drive, such variations become deterministic if they are able to be characterised. Such ability is facilitated by the recent introduction of partial response signalling to hard disk magnetic recording which brings with it the discrete-time sampler and the ability of the microprocessor to analyse signals digitally much more easily than analogue domain alternatives. Simple methods of measuring the step-response pulse width and signal to noise ratio with the partial response channel's electronic components are presented. The expected error rate as a function of recording density and signal to noise ratio is derived experimentally for the PR4 and EPR4 classes of partial response. On the basis of this information and the recording performance it has measured, the adaptive channel is able to implement either PR4 or EPR4 signalling and at any data rate. The capacity advantage over the non-adaptive approach is investigated for the variables previously identified. It is concluded on the basis of this investigation that the proposed adaptive channel could provide significant manufacturing yield and capacity advantages over the non-adaptive approach for a modest increase in electronic complexity.
40
Rakovan, Monica Tsang. "Land use, sediment supply and channel response of southwest Ohio watersheds." Miami University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=miami1321977972.
Full text
41
Soriaga, Joseph Binamira. "On near-capacity code design for partial-response channels /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2005. http://wwwlib.umi.com/cr/ucsd/fullcit?p3167813.
Full text
42
Olivas, Paulo C. "Arctic Ecosystem Responses to Changes in Water Availability and Warming: Short and Long-Term Responses." FIU Digital Commons, 2010. http://digitalcommons.fiu.edu/etd/333.
Full textAbstract:
Arctic soils store close to 14% of the global soil carbon. Most of arctic carbon is stored below ground in the permafrost. With climate warming the decomposition of the soil carbon could represent a significant positive feedback to global greenhouse warming. Recent evidence has shown that the temperature of the Arctic is already increasing, and this change is associated mostly with anthropogenic activities. Warmer soils will contribute to permafrost degradation and accelerate organic matter decay and thus increase the flux of carbon dioxide and methane into the atmosphere. Temperature and water availability are also important drivers of ecosystem performance, but effects can be complex and in opposition. Temperature and moisture changes can affect ecosystem respiration (ER) and gross primary productivity (GPP) independently; an increase in the net ecosystem exchange can be a result of either a decrease in ER or an increase in GPP. Therefore, understanding the effects of changes in ecosystem water and temperature on the carbon flux components becomes key to predicting the responses of the Arctic to climate change. The overall goal of this work was to determine the response of arctic systems to simulated climate change scenarios with simultaneous changes in temperature and moisture. A temperature and hydrological manipulation in a naturally-drained lakebed was used to assess the short-term effect of changes in water and temperature on the carbon cycle. Also, as part of International Tundra Experiment Network (ITEX), I determined the long-term effect of warming on the carbon cycle in a natural hydrological gradient established in the mid 90’s. I found that the carbon balance is highly sensitive to short-term changes in water table and warming. However, over longer time periods, hydrological and temperature changed soil biophysical properties, nutrient cycles, and other ecosystem structural and functional components that down regulated GPP and ER, especially in wet areas.
43
Fritzsch, Katrin. "Plant response to changes in disturbance magnitude." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=97325646X.
Full text
44
Zhou, Shi Huang. "Operational modal decomposition approach for MDOF structures using multi-channel response measurements." Thesis, University of Macau, 2018. http://umaclib3.umac.mo/record=b3950681.
Full text
45
Laneman, J. Nicholas. "Channel estimation and equalization for spread-response precoding systems in fading environments." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/42673.
Full text
46
Coulter, Marinda. "The Response of Naive Channel Catfish to Chemical Cues Associated with Predation." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/3268.
Full textAbstract:
The chemosensory abilities of fishes, are important in order to understand how prey can perceive and avoid predators. Predator-naïve Channel catfish were exposed to four extracts over eight sessions (naïve bass water (NBW), bass that were fed catfish water (BFCW), catfish skin extract (CS), and naïve bass water paired with catfish skin extract (CO)) to determine whether they have an innate predator response to potential chemical cues indicating possible predation risk. Movement was quantified as grid squares crossed, directional changes, and tail beats. Response increased during the first minute following stimulus injection and decreased during the second minute. Channel catfish increased movement upon exposure to stimuli from NBW, CS and CO but not to BFCW. Increased response to bass odor while habituating to catfish skin extract, which presumably contains alarm pheromone, suggests that catfish learned to recognize bass odor without external reinforcement.
47
Tanentzap, Andrew Joseph. "Global vegetation responses to deer : ecosystem changes and recovery." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609232.
Full text
48
Green, Kim Cordelia. "Forests, floods and channel processes : illuminating links between forest harvesting, the flood regime and channel response in snowmelt headwater streams." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45705.
Full textAbstract:
A meta-analysis of four snowmelt catchments with moderate harvest levels (30% to 40%) utilizing a frequency-based approach demonstrates, despite a century’s-worth of studies to the contrary, how harvesting increases the magnitude and frequency of all floods on record including the largest floods (R.I. = 1:50 yrs.) and how such effects increase unchecked with increasing return period as a consequence of changes to both the mean and standard deviation of the flood frequency distribution. Additionally, meta-analysis outcomes reveal up to three-fold increases in the number and duration of peak flows with return periods ranging from 0.6*Q₁.₅ to Q₁₀, which includes floods capable of mobilizing bedload and altering the form of gravel-bed streams. A frequency-based meta-analysis provides new insights concerning the physical processes governing the relation between forests and floods in snowmelt environments that were previously unrecognized using traditional chronological-pairing methods. The dominant process responsible for flood regime changes following harvesting is the increase in basin-average snowmelt rates that are amplified or mitigated by physical characteristics such as aspect distribution, elevation range, slope gradient and amount of alpine area.
The outcomes of a high-resolution, nested-monitoring investigation of hydrologic and geomorphic controls on bedload mobility indicate that flow regime changes from harvesting in snowmelt streams can alter rates of bedload transport, a first-order determinant of channel form in fluvial systems. Regression analysis shows that annual sediment yield is controlled by the number of peaks-over-threshold discharge. During peak events, repeated destabilization of channel armor and re-mobilization of sediment temporarily stored behind LWD generates bedload transport across the entire snowmelt season. However, the potential for channel response to changes in the flow regime depends on characteristics of channel morphology. Study results indicate that patterns of bedload entrainment and mobility are influenced by flow resistance associated with channel form, grain size and LWD while the value of the critical dimensionless shear stress varies with channel gradient, relative and absolute grain effects and flow resistance. Differences in bed texture, gradient and channel form contributes to variations in rates and characteristics of bed mobility, hence differences in potential for alteration due to changes in the flow regime.
49
Bothams, Valerie Frances. "Reflex mechanisms eliciting the changes in heart rate caused by isometric exercise." Thesis, University of Birmingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369171.
Full text
50
Cook, Ritchard Matthew. "Changes in gene expression in response to abscisic acid and environmental stress." Thesis, University of the West of England, Bristol, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293362.
Full text