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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
291

Emerging Seed Enhancements to Reduce the Risk of Sagebrush Post-Fire Seeding Failure

Call, Ryan Scott 01 April 2018 (has links)
The sagebrush (Artemisia spp.) steppe is undergoing rapid ecological change. The degradation of sagebrush steppe rangelands has resulted in the listing of more than 350 animals and plants as species of conservation concern. In addition, there has been a decrease in recreational values, reduced forage production, degraded water resources, and an increase in fire frequency. In the sagebrush steppe, success rates for seeding sagebrush after wildfire are notoriously low. Not only are sagebrush seeds hard to sow due to their small size and associated flower parts, but seedlings are exposed to numerous stresses that lowers their survivability. To improve sowing efficiency and reduce the associated stresses to seedling development we use seed enhancement technologies. In Chapter 1, we explain how a rotary seed coater can be used to agglomerate and apply enhancements to Wyoming big sagebrush (Artemisia tridentata spp. wyomingensis) seed. Using a mix of compost and clay we used a rotary seed coater to create small uniform agglomerates that allowed for enhancements to be applied to the seed. Our study demonstrated that agglomerates have no negative effects on seed germination and increased the overall flow of seed. In Chapter 2, we analyzed the addition of the plant hormone abscisic acid (ABA) in seed coatings. This hormone may delay seed germination and allow seedlings to avoid mortality due to over-winter freezing. We determined effects of different concentrations of ABA on total germination and timing of germination. Using a wet-thermal accumulation model, we estimated germination timing of seeds using soil temperature and water potential data for six different sites in the Great Basin. These models illustrate the variation in germination timing across the Great Basin. From our results we proposed the idea of using ABA to create a bet- hedging strategy in seed mixes to increase the probability that some seeds would germinate when conditions are favorable for seedling success.
292

Acoustic Foundations of Signal Enhancement and Room Acoustics

Smurzynski, Jacek 14 November 2007 (has links)
Book Summary: Chermak and Musiek's two-volume, award-winning handbooks are back in newly revised editions. Extensively revised and expanded, Volume II provides expanded coverage of rehabilitative and professional issues, detailing intervention strategies for children and adults. Volume I provides comprehensive coverage of the auditory neuroscience and clinical science needed to accurately diagnose the range of developmental and acquired central auditory processing disorders in children, adults, and older adults. Building on the excellence achieved with the best-selling 1st editions which earned the 2007 Speech, Language, and Hearing Book of the Year Award the second editions include contributions from world-renowned authors detailing major advances in auditory neuroscience and cognitive science; diagnosis; best practice intervention strategies in clinical and school settings; as well as emerging and future directions in diagnosis and intervention.
293

Development of N-glycan Specific Plant Produced Antibody Therapeutics for a Fine-tuned Immune Response

January 2019 (has links)
abstract: Antibodies are naturally occurring proteins that protect a host during infection through direct neutralization and/or recruitment of the innate immune system. Unfortunately, in some infections, antibodies present unique hurdles that must be overcome for a safer and more efficacious antibody-based therapeutic (e.g., antibody dependent viral enhancement (ADE) and inflammatory pathology). This dissertation describes the utilization of plant expression systems to produce N-glycan specific antibody-based therapeutics for Dengue Virus (DENV) and Chikungunya Virus (CHIKV). The Fc region of an antibody interacts with Fcγ Receptors (FcγRs) on immune cells and components of the innate immune system. Each class of immune cells has a distinct action of neutralization (e.g., antibody dependent cell-mediated cytotoxicity (ADCC) and antibody dependent cell-mediated phagocytosis (ADCP)). Therefore, structural alteration of the Fc region results in novel immune pathways of protection. One approach is to modulate the N-glycosylation in the Fc region of the antibody. Of scientific significance, is the plant’s capacity to express human antibodies with homogenous plant and humanized N-glycosylation (WT and GnGn, respectively). This allows to study how specific glycovariants interact with other components of the immune system to clear an infection, producing a tailor-made antibody for distinct diseases. In the first section, plant-produced glycovariants were explored for reduced interactions with specific FcγRs for the overall reduction in ADE for DENV infections. The results demonstrate a reduction in ADE of our plant-produced monoclonal antibodies in in vitro experiments, which led to a greater survival in vivo of immunodeficient mice challenged with lethal doses of DENV and a sub-lethal dose of DENV in ADE conditions. In the second section, plant-produced glycovariants were explored for increased interaction with specific FcγRs to improve ADCC in the treatment of the highly inflammatory CHIKV. The results demonstrate an increase ADCC activity in in vitro experiments and a reduction in CHIKV-associated inflammation in in vivo mouse models. Overall, the significance of this dissertation is that it can provide a treatment for DENV and CHIKV; but equally importantly, give insight to the role of N-glycosylation in antibody effector functions, which has a broader implication for therapeutic development for other viral infections. / Dissertation/Thesis / Doctoral Dissertation Molecular and Cellular Biology 2019
294

Effects of Expectations on Cognitive Enhancement Interventions in Young and Older Adults

Rabipour, Sheida 20 September 2018 (has links)
With increasing life expectancy and global population of older adults, preserving cog- nitive function throughout life represents a growing priority. Numerous approaches to cognitive enhancement exist, but few have scientific merit. Among the most preva- lent – and commercialized – approaches are cognitive training (“brain training”) and non-invasive brain stimulation through electric currents applied at the surface of the scalp. The present dissertation describes a collection of work contextualizing the appeal of these cognitive enhancement methods and addressing some of the most pervasive limitations of research in this field thus far. One largely ignored issue in cognitive intervention research pertains to people’s expectations of programs and their relationship with intervention outcomes. In a series of initial studies, we developed and validated the Expectation Assessment Scale (EAS), a tool created to measure as well as prime expectations of outcomes in the context of cognitive enhancement interventions. In our first two studies, we probed expectations of cognitive training or non-invasive brain stimulation in over 1,000 young, middle-aged, and older adults. Ratings on the EAS suggested that older adults may have particularly high expectations of cognitive training, but that expectations can be primed to increase or decrease – at least in hypothetical scenarios. We used these data to assess the psychometric properties of the EAS with item-response theory, and confirmed its internal consistency. Next, we incorporated the EAS into two cognitive enhancement trials, one in- vestigating a computerized cognitive training intervention in nearly 100 older adults and another examining non-invasive brain stimulation in nearly 100 young adults. Both trials had a double-blind balanced-placebo design in which participants were assigned to the intervention or control condition, and then subdivided to receive ei- ther high or low expectation priming (i.e., primed to have high or low expectations of the program’s effectiveness). Although expectation ratings replicated our previous findings, results from these trials suggest little, if any, effect of either expectations or the intervention on performance outcomes. We nevertheless found that participants enjoyed their assigned program and that those who received high expectation prim- ing tended to report a more positive experience. Our findings put into question the effectiveness of such interventions and support the need for more rigorous trials of cognitive enhancement.
295

Multi-Frequency Processing for Lumen Enhancement with Wideband Intravascular Ultrasound

Carrillo, Rory A 01 September 2010 (has links)
The application of high frequency ultrasound is the key to higher resolution intravascular ultrasound (IVUS) images. The need to further improve the IVUS spatial resolution may drive the transducer center frequency even higher than the current 40 MHz range. However, increasing the center frequency may be challenging as it leads to stronger scattering echoes from blood. The high level of blood scattering echoes may obscure the arterial lumen and make image interpretation difficult. Blood backscatter levels increase with transmission center frequency at a much greater rate compared to arterial tissue. These different frequency dependencies provide a potential method to distinguish blood from tissues by means of multi-frequency processing techniques. To obtain a good blood-tissue contrast with sufficient signal-to-noise ratio, a system with a wider bandwidth is highly desirable. The method described in this paper is based on the ratio of the received signal power between the high (60 MHz) and low (25 MHz) frequency ranges from a novel 40 MHz wideband IVUS catheter. In this paper we will present our in vitro experiment work on porcine blood and a tissue-mimicking arterial wall. Results of multi-frequency processing indicate that blood, at higher frequencies, has a greater backscatter power that is 8X greater than arterial tissue, suggesting this technique will provide a greater contrast between the blood-wall lumen boundary for coronary imaging.
296

Contribution à une théorie de la justice cognitive : l’amélioration biomédicale de l’attention des enfants : le cas de la Ritaline / Contribution to a theory of a cognitive justice : the biomedical enhancement of children’s attention : the case for Ritalin

Castex, Elisabeth de 20 May 2015 (has links)
Dans son analyse de la démarche de socialisation des enfants, Émile Durkheim met en garde contre « toute action positive destinée à imprimer une orientation déterminée à l’esprit de la jeunesse ». Notre thèse explore les déclinaisons contemporaines de ces « actions positives » qui émanent de l’État et de différents éléments de la société, et qui, en modifiant le fonctionnement cérébral, entendent orienter le comportement d’enfants non malades vers davantage d’attention et moins d’impulsivité. Cette orientation recouvre un enjeu politique : la réduction des inégalités dans les capacités cérébrales, qui tendent à devenir des inégalités majeures dans la société de performance contemporaine. Notre objet de recherche est constitué par les nouveaux pouvoirs exercés par les adultes sur les enfants, au moyen de techniques biomédicales nouvelles, en particulier par des substances chimiques : les médicaments psychostimulants. Les moyens biomédicaux s’exercent directement sur le fonctionnement cérébral, de manière intrusive, sans la médiation du langage et de la communication, et posent de ce fait des nouvelles questions liées à leur puissance d’action. Ce travail se donne pour objectif de contribuer à une théorie de la justice cognitive pour les enfants. Les nouvelles significations des inégalités d’attention dans les apprentissages, les enjeux sociaux de ces inégalités dans une société de performance et les nouvelles possibilités d’intervention biomédicales sur le fonctionnement cérébral des enfants convergent vers de nouvelles formes dans l’économie psychique des enfants. Il semble possible d’interpréter ces nouvelles forces à l’œuvre comme s’inspirant d’un principe de justice. Le débat autour d’une justice cognitive reflète alors le caractère ressenti comme insupportable socialement des inégalités d’attention et le caractère ressenti comme inévitable de la réponse pharmacologique qui lui est associée. Le recours à la théorie d’une justice cognitive implique, pour l’analyse des pratiques de prescription massives de Ritaline, de se situer au-delà du paradigme habituel de contrôle social et de contrôle des comportements par la médicalisation de la société. / The analysis of children’s socialization process made by Emile Durkheim warns us against any actions intended to have an impact on the orientation of the young spirits. Our thesis explores the contemporary range of these positive actions issued from the state as well as from different parts of society. Those ones, by modifying the proper cerebral functioning, are guiding the behaviour of non-ill toward more attention and less impulsivness. This subject has a significant political concern: the reduction of cerebral inequal capacities which tend to become more and more important in our contemporary performance oriented society. Our research investigates new powers exerciced by adults on children, through the use of modern biomedical techniques, and particuly through psychostimulant pharmaceuticals. Biomedical tools directly reach the functioning brain, in an intrusive way, without the intermediate of either language or communication, which therefore arises new questions about their power of action. The aim of this study is to contribute to a theory of a cognitive justice for children. The new meanings of the inequalities of focus in learning, the social issues of these inequalities in a performance society and the new possibilities of biomedical intervention on the functioning brain converge towards new forms in psychic economy of children. It seems possible to interpret those new forces in action through a principle of justice. The debate around a cognitive justice reflects the unbearable social aspect of the disparities in attention capacity and the hypothetically unavoidable pharmacological answers associated to it. The solution of the theory of cognitive justice involves, for the pratical analysis of the massive instruction of Ritaline, to be situated beyond the usual paradigm of social control and behavioural control through society’s medicalization.
297

Improved theoretical prediction of nanoparticle stability and the synthesis, characterization, and application of gold nanopartticles of various morphology in surface-enhanced infrared spectroscopy

Wijenayaka, A. K. Lahiru Anuradha 01 July 2015 (has links)
The overarching objective of the investigations discussed herein is the development of a model experimental system for surface-enhanced infrared absorption (SEIRA) spectroscopy, with potential applicability in higher order infrared spectroscopic techniques, specifically, surface-enhanced two-dimensional infrared (SE-2D IR) spectroscopy. Theoretical predictions that accurately predict the stability of functionalized nanoparticles enable guided design of their properties but are often limited by the accuracy of the parameters used as model inputs. Hence, first, such parameterization limitations for the extended DLVO (xDLVO) theory are overcome using a size-dependent Hamaker constant for gold, interfacial surface potentials, and tilt angles of self-assembled monolayers (SAMs), which collectively improves the predictive power of xDLVO theory for modeling nanoparticle stability. Measurements of electrical properties of functionalized gold nanoparticles validate the predictions of xDLVO theory using these new parameterizations illustrating the potential for this approach to improve the design and control of the properties of functionalized gold nanoparticles in various applications. Next, a series of experiments were conducted to elucidate the behavior of various infrared active molecules in the presence of spherical gold nanoparticles of average diameter ∼20 nm. Here, the spectroscopic anomalies, specifically the shifted vibrational frequency and the dispersive lineshape observed in the infrared spectra for SCN- in the presence of gold nanoparticles provide direct evidence of SIERA. Nevertheless, it was evidenced that nanomaterial with plasmonic properties that extends into the infrared wavelengths are imperative in observing efficient infrared enhancements. Hence, nanomaterial indicating plasmonic properties extending into the infrared wavelengths were synthesized via a straightforward, seedless, one-pot synthesis. The gold nanostars prepared here indicated plasmonic behavior clearly extending into the near infrared, with simple plasmonic tunability via changing the buffer concentration used during synthesis. The systematic understanding achieved here in terms of theoretical prediction of nanoparticle stability, origin of infrared spectral anomalies in the presence of nanomaterials, and the preparation of infrared plasmonic material, collectively provides a resilient framework for the further investigation of surface-enhanced infrared spectroscopic techniques including SEIRA and SE-2D IR spectroscopies.
298

Simulation and implementation of nonlinear control systems for mineral processes.

Kam, Kiew M. January 2000 (has links)
Differential geometric nonlinear control of a multiple stage evaporator system of the liquor burning facility associated with the Bayer process for alumina production at Alcoa Wagerup alumina refinery, Western Australia was investigated.Mathematical models for differential geometric analysis and nonlinear controller synthesis for the evaporator system were developed. Two models, that were structurally different from each other, were used in the thesis for simulation studies. Geometric nonlinear control structure, consisting of nonlinear state feedback control laws and multi-loop single-input single-output proportional-integral controllers, were designed for the industrial evaporator system. The superiority of the geometric nonlinear control structure for regulatory control of the evaporator system was successfully demonstrated through computer simulations and real-time simulator implementation. The implementation trial has verified the practicality and feasibility of these type of controllers. It also re-solved some practical issues of the geometric nonlinear control structure for industrial control applications. In addition, the implementation trial also established a closer link between the academic nonlinear control theory and the industrial control practices.Geometric nonlinear output feedback controller, consisting of the geometric nonlinear control structure and reduce-order observer was proposed for actual plant implementation on the evaporator system on-site. Its superior performance was verified through computer simulations, but its feasibility on the evaporator system on-site has yet to be investigated either through simulator implementation or actual plant implementation. This investigation was not performed due to the time constraint on the preparation of this thesis and the inavailability of the plant personnel required for this implementation.Robust ++ / nonlinear control structures that are simple and computationally efficient have been proposed for enhancing the performance of geometric nonlinear controllers in the presence of plant/model mismatch and/or external disturbances. The robust nonlinear control structures are based on model error compensation methods. Robustness properties of the proposed robust nonlinear control structures on the evaporator system were investigated through computer simulations and the results indicated improved performance over the implemented geometric nonlinear controller in terms of model uncertainty and disturbance reductions.A software package was developed in MAPLE computing environment for the analysis of nonlinear processes and the design of geometric nonlinear controllers. This developed symbolic package is useful for obtaining fast and exact solutions for the analysis and design of nonlinear control systems. Procedures were also developed to simulate the geometric nonlinear control systems. It was found that MAPLE, while it is superior for the analyses and designs, is not viable for simulations of nonlinear control systems. This was due to limitation of MAPLE on the physical, or virtual, memory management. The use of both symbolic and numeric computation for solutions of nonlinear control system analysis, design and simulation is recommended.To sum up, geometric nonlinear controllers have been designed for an industrial multiple stage evaporator system and their simplicity, practicality, feasibility and superiority for industrial control practices have been demonstrated either through computer simulations or real-time implementation. It is hoped that the insights provided in this thesis will encourage more industry-based projects in nonlinear control, and thereby assist in closing the widening gap between academic nonlinear control theory and industrial control ++ / practice.Keywords: geometric nonlinear control, input-output linearization, multiple stage evaporator, robust geometric nonlinear control, control performance enhancement.
299

An FPGA Based Software/Hardware Codesign for Real Time Video Processing : A Video Interface Software and Contrast Enhancement Hardware Codesign Implementation using Xilinx Virtex II Pro FPGA

Wang, Jian January 2006 (has links)
<p>Xilinx Virtex II Pro FPGA with integrated PowerPC core offers an opportunity to implementing a software and hardware codesign. The software application executes on the PowerPC processor while the FPGA implementation of hardware cores coprocess with PowerPC to achieve the goals of acceleration. Another benefit of coprocessing with the hardware acceleration core is the release of processor load. This thesis demonstrates such an FPGA based software and hardware codesign by implementing a real time video processing project on Xilinx ML310 development platform which is featured with a Xilinx Virtex II Pro FPGA. The software part in this project performs video and memory interface task which includes image capture from camera, the store of image into on-board memory, and the display of image on a screen. The hardware coprocessing core does a contrast enhancement function on the input image. To ease the software development and make this project flexible for future extension, an Embedded Operating System MontaVista Linux is installed on the ML310 platform. Thus the software video interface application is developed using Linux programming method, for example the use of Video4Linux API. The last but not the least implementation topic is the software and hardware interface, which is the Linux device driver for the hardware core. This thesis report presents all the above topics of Operating System installation, video interface software development, contrast enhancement hardware implementation, and hardware core’s Linux device driver programming. After this, a measurement result is presented to show the performance of hardware acceleration and processor load reduction, by comparing to the results from a software implementation of the same contrast enhancement function. This is followed by a discussion chapter, including the performance analysis, current design’s limitations and proposals for improvements. This report is ended with an outlook from this master thesis.</p>
300

Enhancement of X-ray Fluoroscopy Image Sequences using Temporal Recursive Filtering and Motion Compensation

Forsberg, Anni January 2006 (has links)
<p>This thesis consider enhancement of X-ray fluoroscopy image sequences. The purpose is to investigate the possibilities to improve the image enhancement in Biplanar 500, a fluoroscopy system developed by Swemac Medical Appliances, for use in orthopedic surgery.</p><p>An algorithm based on recursive filtering, for temporal noise suppression, and motion compensation, for avoidance of motion artifacts, is developed and tested on image sequences from the system. The motion compensation is done both globally, by using the theory of the shift theorem, and locally, by subtracting consecutive frames. Also a new type of contrast adjustment is presented, received with an unlinear mapping function.</p><p>The result is a noise reduced image sequence that shows no blurring effects upon motion. A brief study of the result shows, that both the image sequences with this algorithm applied and the contrast adjusted images are preferred by orthopedists compared to the present images in the system.</p>

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