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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.
271

OsteoBLAST rotina computacional de análise molecular global aliada à biologia sistêmica e aplicada à produção de biomateriais /

Ferreira, Marcel Rodrigues. January 2017 (has links)
Orientador: Willian Fernando Zambuzzi / Resumo: As tendências na terapia com implantes têm incluído a modificação de suas superfícies utilizando ferramentas de nanotecnologia e princípios de bioengenharia, aumentando seu desempenho quando implantado. Embora muito se tenha alcançado em ferramentas para desenvolvimento destes materiais, metodologias de avaliação biológicas não avançaram nesta velocidade. Amparados por ferramentas de bioinformática e utilizando conceitos de biologia sistêmica, o objetivo deste trabalho foi produzir uma metodologia computacional, alternativa ao uso de experimentação animal, capaz de detectar e analisar o quinoma da resposta da interação célula-biomaterial, obtida com ensaio de microarranjo de peptídeos. Estes dados servirão para a construção de um banco de dados para guiar a produção de biomateriais para a área médico-odontológica. Batizaremos este de OsteoBLAST. Para tanto, fizemos uso de superfícies de titânio com diferentes superfícies (maquinado e duplo ataque ácido), as quais foram desafiadas com o cultivo de células tronco indiferenciadas. As amostras biológicas foram utilizadas para avaliar quinases diferencialmente ativadas através de substratos sintéticos, cuja metodologia é conhecida como PamGene, as quais foram reunidas em um banco de dados chamado OsteoBLAST, o qual fora constituído através de um algoritmo em quatro etapas que selecionou os resultados confiados de PamGene, em seguida obetendo o quinoma diferencial e um nível de similaridade com superfícies amplamente usadas na roti... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Current trends in implant therapy have included the modification of their surfaces using nanotechnology tools and principles of bioengineering, increasing their performance when deployed. Although much has been achieved in tools for developing these materials, biological analysis methodologies did not advance at this speed. Supported by bioinformatics tools and using concepts of systemic biology, the objective of this work was to produce a computational methodology, alternative to the use of animal experimentation, capable of detecting and analyzing the kinome of the response of the cell-biomaterial interaction, obtained with microarray peptides. These data will serve to build a database to guide the production of biomaterials for the medical-dental area. We will baptize this one from OsteoBLAST. To do so, we made use of titanium surfaces with different surfaces (machined and double acid etched), which were challenged with the cultivation of undifferentiated stem cells. Biological samples were used to evaluate differentially activated kinases through synthetic substrates, a methodology known as PamGene, as the banks were assembled in a database called OsteoBLAST, which consists of a four-step algorithm that selected the results confident of PamGene, then obtaining the differential kinome and a level of similarity with surfaces widely used in the routine. Our results showed that the EGRF, ENO2, EPHA4, FRK, KRT6B, NCF1, PDPK1, PDGFRB and KDR as proteins involved in this molecul... (Complete abstract click electronic access below) / Mestre
272

Contribuições da teoria da estimação para modulações digitais que utilizam sinais caóticos. / Contributions of the estimation theory to digital modulations that use chaotic signals.

Marcio Eisencraft 17 April 2006 (has links)
Neste trabalho investiga-se o emprego de técnicas de estimação em sistemas de modulação digital que utilizam sinais caóticos. Inicialmente, aspectos básicos das teorias de sistemas não-lineares e de modulações digitais são revisitados seguidos de técnicas recentemente propostas de modulações digitais caóticas com receptores por correlação coerente, não-coerente e diferencial: o CSK (Chaos Shift Keying), o DCSK (Differential Chaos Shift Keying) e algumas de suas variantes, em especial o FM-DCSK (Frequency Modulated DCSK). Nessa descrição, utiliza-se a notação de equivalente passa-baixas de tempo discreto para facilitar a comparação com modulações digitais convencionais. Deduz-se o limite de Cramér-Rao para a estimação da condição inicial de órbitas caóticas em função de propriedades estatísticas do mapa que as gerou e descrevem-se dois estimadores para elas: o MLE (Maximum Likelihood Estimator) que se aplica a mapas com densidade invariante uniforme e o algoritmo de Viterbi para o qual se apresenta uma generalização a fim de aplicá-lo a uma classe maior de mapas. Por apresentar ganho de estimação maior na faixa de relação sinal-ruído de interesse, este último é utilizado em propostas de sistemas de modulação digital que utilizam estimação de órbitas para detectar o símbolo enviado: o ML-CSK (Maximum Likelihood CSK) modificado para poder usar mapas com densidade invariante não-uniforme, empregando um ou dois mapas e o ML-DCSK (Maximum Likelihood DCSK). Por simulação, avaliou-se o desempenho em termos de taxa de erro desses sistemas sob ruído branco aditivo gaussiano. / In this work, we investigate the use of estimation techniques to digital modulation systems that use chaotic signals. Initially, basic aspects of nonlinear systems and digital modulation theory are reviewed followed by currently proposed techniques of chaotic digital modulation with coherent, noncoherent and differential correlation receivers: CSK (Chaos Shift Keying), DCSK (Differential Chaos Shift Keying) and some of its variants in special FM-DCSK (Frequency Modulated DCSK). These systems are described using a discrete-time lowpass equivalent model to facilitate comparison with conventional digital modulation systems. We derive Cramér-Rao lower bounds for the estimation of the initial condition of chaotic orbits as a function of the statistical properties of the chaos generating map and describe two chaotic orbits estimators: the MLE (Maximum Likelihood Estimator) that applies only to maps with uniform invariant density and the Viterbi algorithm for which a generalization is presented that allows its application to a broader class of maps. Because of the larger estimation gains attained in the signal-to-noise ratio range of interest, the latter is used in proposed digital modulation systems that use orbit estimation to detect the transmitted symbol: ML-CSK (Maximum Likelihood CSK) modified to allow maps with nonuniform invariant density using one map or two maps and ML-DCSK (Maximum Likelihood DCSK). The performance of these systems in terms of symbol error rate is accessed via simulation under additive white gaussian noise perturbations.
273

The role of DLG-MAGUKs in mediating signaling specificity at the postsynaptic density

Duda, Joana-Kristin 18 December 2018 (has links)
No description available.
274

Effects of oscillatory forcing on hydrologic systems under extreme conditions: a mathematical modeling approach

Fonley, Morgan Rae 01 August 2015 (has links)
At the large watershed scale, we emphasize the effects of flow through a river network on streamflow under dry conditions. An immediate consequence of assuming dry conditions is that evapotranspiration causes flow in the river network to exhibit oscillations. When all links in the river network combine their flow patterns, the oscillations interact in ways that change the timing and amplitude of the streamflow waves at the watershed outlet. The geometric shape of the river network is particularly important, so we develop an analytic solution for streamflow which emphasizes that importance. Doing hydrology backward is a strategy recently developed by several researchers to deal with uncertainty in measurements of forcing terms applied to hydrologic models. The strategy has also been applied to resolve the assumption of homogeneity on realistic catchments that exhibit many heterogeneous properties. In this work, we demonstrate hydrology in the backward direction applied to two examples: using streamflow at the catchment scale to determine runoff at the hillslope scale and using the hillslope runoff to infer the applied evapotranspiration forcing under the assumption of dry conditions. In order to work across scales, we utilize the analytic solution for streamflow at the outlet of a river network. At the hillslope scale, we develop a soil model to create fluxes consistent with observed soil processes.
275

EVALUATION OF THEORETICAL AND PRACTICAL SIGNAL OPTIMIZATION TOOLS IN MICROSIMULATION ENVIRONMENT

Unknown Date (has links)
Traffic simulation and signal timing optimization are classified in structure into two main categories: (i) Macroscopic or Microscopic; (ii) Deterministic or Stochastic. Performance of the optimized signal timing derived by any tool is influenced by the methodology used in how calculations are executed in a particular tool. In this study, the performance of the optimal signal timing plans developed by two of the most popular traffic analysis tools, HCS and Tru-Traffic, each of them has its inbuilt objective function(s) to optimize signal timing for intersection, is compared with an ideal and an existing timing plans (base case) for the area of study using the microsimulation software VISSIM. An urban arterial with 29 intersections and high traffic in Fort Lauderdale, Florida serves as the test bed. To eliminate unfair superiority in the results, all experiments were performed under identical geometry and traffic conditions in each tool. Comparison of the optimized plans is conducted on the basis of average delay, average stopped delay, average number of stops, number of vehicles completed trips, latent delay, and latent demand from the simulated vehicle network performance evaluation results in VISSIM. The results indicate that, overall, HCS with its overall delay objective and the Tru-Traffic programs produce signal timing with comparable quality that performed similar to the un-optimized base case for most of the performance measures. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection
276

Approach-avoidance and optimism

Rose, Jason Paul 01 July 2009 (has links)
It is a widely assumed principle that organisms reflexively approach possibilities for pleasure and avoid possibilities for pain. However, highly evolved organisms not only reflexively react to future possibilities of pleasure vs. pain, but also evaluate the chance or risk of actually experiencing such possibilities. Given the import of optimism judgments in shaping behavior and other outcomes, the main goal of the current research was to examine the relationship between the rudimentary systems of approach-avoidance that orient us toward possible outcomes in the environment and the higher-order optimism judgments we make when evaluating whether such outcomes are likely to occur. To this end, two experiments examined the impact of approach-avoidance cues in shaping participants' optimism judgments about experiencing positive and negative future life events. For the primary operationalization of approach-avoidance, college student participants engaged in arm flexion (a motor movement associated with approach) or arm extension (a motor movement associated with avoidance) while simultaneously making optimism judgments about experiencing a range of positive and negative events in the future. A secondary operationalization involved correlations computed between participants' chronic personality tendencies related to approach-avoidance (e.g., positive vs. negative affectivity) and their optimism judgments. The results of these experiments revealed complexities in the relationship between approach-avoidance and optimism, suggesting that when, how and why approach-avoidance cues will shape optimism may critically depend upon 1) the specific operationalization of approach-avoidance, 2) how optimism is measured, and 3) characteristics of the outcomes under consideration. Explanations for the complexities in the results are offered, and attempts are made to link the current work to broader theoretical and practical aspects of the connection between approach-avoidance and optimism.
277

[en] A PROBABILISTIC APPROACH IN SIGNAL MODELING FOR NOISE RADARS THAT EMPLOY FREQUENCY MODULATED PULSES / [pt] MODELAGEM PROBABILÍSTICA DE SINAIS EM RADARES DE RUÍDO QUE UTILIZAM PULSOS SENOIDAIS MODULADOS EM FREQUÊNCIA

LEANDRO GUIMARAES PRALON 09 April 2014 (has links)
[pt] Radares são sistemas eletromagnéticos de detecção e localização de objetos refletores. Sua operação consiste na transmissão de formas de onda e na detecção e processamento do sinal refletido no alvo, visando extrair algumas características deste (e.g. posição, velocidade, direção, tipo de alvo). Radares de ruído, por sua vez, são sistemas que transmitem sinais com forma de onda aleatória e que, por este motivo, apresentam elevado desempenho em presença de interferências externas, intencionais ou não, e supressão da ambiguidade em distância na detecção de alvos. O presente trabalho desenvolve inicialmente uma modelagem probabilística dos sinais envolvidos em radares de ruído. Esta modelagem permite a obtenção de expressões fechadas para funções autocorrelação, densidades espectrais de potência, funções correlação cruzada e ganhos de processamento associadas aos diversos sinais envolvidos. Com base nesta modelagem, e feita uma análise comparativa de radares que utilizam compressão de pulso e integração em sua cadeia de recepção. Mais especificamente, são comparados radares de ruído com radares tradicionais (que utilizam formas de onda determinísticas - chirps) operando em cenários que permitem avaliar aspectos como a resolucao em distância, o nível de lóbulos secundários e a eliminação de ambiguidades. / [en] Radars are electromagnetics systems used for detecting and locating reflecting objects. Their operation is based on the transmition of waveforms and on the detection and processing of the reflected signal so that some targets can be estimated (e.g. position, velocity, direction and type of target). Noise radars are systems that use random signals as the transmitting waveform and that for this reason present high performance against external interference, intentional or not, and the suppression of range ambiguity in the detection of targets. The present work initially develops a probabilistic model for the random signals involved in Noise Radars. This model allows for derivation of closed forms expressions for autocorrelation functions, power spectral densities, processing gains, and cross-correlation functions of the random signals involved. Based on this model, a comparison of radars that employ pulse compression and integration in their receivers. More specifically, Noise Radars are compared to traditional radars that use deterministic waveforms (chirps) under different scenarios which are chosen so that some specific aspects like range resolution, side-lobe levels and range ambiguity elimination can be evaluated.
278

A Case-Based Reasoning System for the Diagnosis of Individual Sensitivity to Stress in Psychophysiology

Begum, Shahina January 2009 (has links)
<p>Increased stress is a continuing problem in our present world. Especiallynegative stress could cause serious health problems if it remainsundiagnosed/misdiagnosed and untreated. In the stress medicine, clinicians’measure blood pressure, ECG, finger temperature and breathing rate during anumber of exercises to diagnose stress-related disorders. One of the physiologicalparameters for quantifying stress levels is the finger temperature that helps theclinicians in diagnosis and treatment of stress. However, in practice, it is difficultand tedious for a clinician to understand, interpret and analyze complex, lengthysequential sensor signals. There are only few experts who are able to diagnose andpredict stress-related problems. A system that can help the clinician in diagnosingstress is important, but the large individual variations make it difficult to build sucha system.This research work has attempted to investigate several artificial Intelligencetechniques to develop an intelligent, integrated sensor system for diagnosis andtreatment plan in the Psychophysiological domain. To diagnose individualsensitivity to stress, case-based reasoning is applied as a core technique to facilitateexperience reuse by retrieving previous similar cases. Further, fuzzy techniques arealso employed and incorporated into the case-based reasoning system to handlevagueness, uncertainty inherently existing in clinicians reasoning process. Thevalidation of the approach is based on close collaboration with experts andmeasurements from twenty four persons used as reference.Thirty nine time series from these 24 persons have been used to evaluate theapproach (in terms of the matching algorithms) and an expert has ranked andestimated similarity which shows a level of performance close to an expert. Theproposed system could be used as an expert for a less experienced clinician or as asecond option for an experienced clinician to their decision making process.</p> / Integrated Personal Health Optimizing System (IPOS)
279

Using Metering Signals at Roundabouts with Unbalanced Flows to Improve the Traffic Condition : The Case Study of Kannik Area in Stavanger / Using Metering Signals at Roundabouts with Unbalanced Flows to Improve the Traffic Condition : The Case Study of Kannik Area in Stavanger

Mosslemi, Marjan January 2008 (has links)
<p>In some roundabouts, just relying on the "right of way" regulations results in long queues forming along the approaches. This usually happens when a roundabout suffers from unbalanced flow patterns (one or two of the approaches convey much heavier traffic compared to the others). There is an idea that signalization of roundabouts can be useful as a countermeasure for such a problem, especially during peak hours. In that case, signal operation can come in many forms, including full-time control, part-time control, or metering. One problem that seems to be facing engineers when signalizing roundabouts is lacking a general set of patterns or guidelines to choose an appropriate form of signalization and apply it efficiently in different situations. There is also a need for a comprehensive review over the available literature concerning signalization of roundabouts. In this thesis, a review of literature regarding signalization of roundabouts is carried out. Moreover, a roundabout in Stavanger with unbalanced traffic flows is studied in order to find an appropriate signalization scenario which can improve the traffic situation. The network is modeled and simulated in AIMSUN.</p>
280

Sexual Signals and Speciation : A Study of the Pied and Collared Flycatcher

Haavie, Jon January 2004 (has links)
<p>Speciation is the process in which reproductive barriers evolve between populations. In this thesis I examine how sexual signals contribute to the maintenance, reinforcement or breakdown of reproductive barriers.</p><p>Male pied flycatchers (<i>Ficedula hypoleuca</i>) and collared flycatchers (<i>F. albicollis</i>) differ in song and plumage traits. However, where the two species coexist, several pied flycatchers sing a song resembling the collared flycatcher (mixed song). Mixed song is not caused by introgression from the collared flycatcher but is due to heterospecific copying. Mixed song provokes aggressive behaviour in collared flycatcher males and leads to heterospecific pairing and maladaptive hybridization. </p><p>The species differences in song were found to be larger in an old than a young hybrid zone. This was due to a reduction in the frequency of mixed song in the pied flycatcher and a divergence in the song of the collared flycatcher. Apparently, mixed song causes maladaptive hybridization, which over time leads to reinforcement of reproductive barriers by a song divergence.</p><p>Previous studies have shown that a character displacement in male plumage traits reinforces species barriers. Hence both plumage and song divergence reduce the incidence of hybridization. The evolution of male plumage traits has been so rapid, or selection has been so strong that rapidly evolving molecular markers are unable to trace it.</p><p>Hybrid females mate with a male of the same species as their father. Previous studies have shown that females use male plumage traits controlled by genes linked to the sex chromosomes (the Z) in species recognition. An association between preference and a sex-linked trait through the paternal line may render reinforcement of reproductive barriers more likely.</p><p>In conclusion, sexual signals are affected by species interactions that cause breakdown or reinforcement of reproductive barriers.</p>

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