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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.
1

Prognostic value of the blinking reflex to visual threat in comatous patients = Valor prognóstico do reflexo de piscar à ameaça visual em pacientes comatosos / Valor prognóstico do reflexo de piscar à ameaça visual em pacientes comatosos

Leite, Juliana Valeria, 1977- 23 August 2018 (has links)
Orientador: Donizeti Cesar Honorato / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-23T19:15:40Z (GMT). No. of bitstreams: 1 Leite_JulianaValeria_M.pdf: 641050 bytes, checksum: b62398f140661279efb6ea212dc9afcf (MD5) Previous issue date: 2013 / Resumo: A avaliação do nível de consciência faz parte da rotina da equipe multiprofissional que conduz pacientes em coma. Sinais que possam representar a melhora do nível de consciência destes pacientes são constantemente buscados. Atualmente sabe-se que alguns fatores, como por exemplo, a resposta motora na escala de coma de Glasgow (ECG) e a apresentação do reflexo fotomotor apresentam valor prognóstico, porém nenhum deles é relacionado diretamente ao despertar destes pacientes. O objetivo deste estudo foi o de relacionar a presença do reflexo de piscar à ameaça visual (RPAV), com o despertar de pacientes comatosos e evidenciar o seu valor prognóstico. Para tanto foi feito um estudo retrospectivo com os dados obtidos em prontuários do serviço de arquivos médicos do Hospital das Clínicas da Universidade Estadual de Campinas (HC-UNICAMP) de pacientes internados nas enfermarias de neurologia clinica e neurocirurgia entre os períodos de abril de 2005 a abril de 2010. Foram selecionados 975 prontuários correspondentes ao diagnóstico de traumatismo cranioencefálico e acidente vascular encefálico. Destes, foram selecionados 119 prontuários de pacientes que se enquadraram nos critérios de inclusão representados pela resposta motora menor ou igual a quatro na ECG na admissão hospitalar e a descrição do RPAV durante o período de internação sendo excluídos os pacientes com resposta motora na admissão hospitalar superior a quatro, que não apresentassem a descrição da avaliação do RPAV ou que tivessem patologias neurológicas associadas às mencionadas como fator de seleção para os prontuários. Foram analisados os dados relativos ao sexo, diagnóstico clínico, resposta motora isolada e ao Glasgow total na admissão e alta hospitalar, a apresentação do RPAV durante o período de internação e a evolução clínica do paciente que foi representada pelo despertar, traduzido pela resposta motora seis ou cinco na ECG, evolução ao estado vegetativo persistente e óbito. A análise estatística demonstrou através da análise de regressão logística univariada e multivariada com critério Stepwise de seleção de variáveis uma associação entre a apresentação positiva do RPAV durante o período de internação e o despertar dos pacientes estudados (p<0.001). Todos os 51 pacientes que apresentaram o reflexo despertaram enquanto os pacientes que não apresentaram o reflexo não despertaram, evoluindo ao estado vegetativo persistente (24 pacientes) ou ao óbito (44 pacientes). Os pacientes que apresentaram o reflexo positivo durante o período de internação apresentaram uma maior possibilidade de despertar (11.685.00 vezes maior) dos que não o apresentaram adotando-se o nível de significância para os testes estatísticos de 5%, ou seja, p<0.05. O presente estudo demonstrou que o RPAV apresenta valor prognostico, estando sua apresentação positiva diretamente associada ao despertar destes pacientes / Abstract: The level of consciousness assessment is part of the hospital routine in comatose patients. Signs that may indicate cognitive improvement in these patients are constantly searched. Nowadays it is kwon that some features represent prognostic value, however, none relates directly with awakening in coma patients. The main purpose of this study was to associate the presence of the blinking reflex as a response to a visual threat with awakening in coma patients. We reviewed medical records from University of Campinas Clinical Hospital from patients diagnosed with stroke and traumatic brain injury (TBI) who stayed in the hospital neurological ward from April 2005 to April 2010. We reviewed 975 medical records. 119 patients were included; on admission they presented a score four or less for motor response in Glasgow Coma Scale (GCS) and description RPVA during hospitalization, being excluded patients with diagnoses other than those cited and motor response at admission more than four, which did not present the description of the assessment the blinking reflex or had neurological pathologies associated with those mentioned as selection factor for records. We gathered information from the charts regarding sex, disease, GCS total score, GCS motor score on admission and discharge, the presence or absence of the blinking reflex and level of consciousness on discharge, characterized as awakening, persistent vegetative state or death. Statistical analysis demonstrated through the analysis of univariate and multivariate logistic regression with stepwise selection criterion variables of a direct association between a positive blinking reflex of to visual threat during the period of hospitalization awakening in our cohort (p<0.001) . All the 51 patients with a positive reflex awoke, while patients with a negative reflex don't awakening evolved to persistent vegetative state (24) or death (44). A positive blinking reflex to visual threat during hospitalization increases the chance of awakening by 11.685.00 times when compared with patients with a negative reflex. The blinking reflex as a response to a threat has great prognostic value while its positivity is directly associated with awakening in coma patients / Mestrado / Ciencias Biomedicas / Mestra em Ciências Médicas
2

Jednomolekulární spektroskopie fotosyntetických antenních systémů / Jednomolekulární spektroskopie fotosyntetických antenních systémů

Malý, Pavel January 2014 (has links)
No description available.
3

Investigating the relation between non-radiative decay process and surface trap states in the CdSe quantum dots

Tsai, Chang-han 23 August 2011 (has links)
Nanocrystal has non-negligible ratio of the surface atoms. The photophysics of the nanocrystal is strongly influenced by the surface states.There are two surface-related phenomena: the on-off blinking and the red-emission. On-off blinking is a phenomenon commonly observed in thesingle emitters, such as dye molecules and semiconductor quantum dots (QD).In the QD, the charged state caused by the charge transferring from the core to the surface states explains the off-state. Another surface-related phenomenon is the red-emission, which is the emission from the low-lying surface trapped states. This thesis investigates the correlation between the on-off blinking and the red-emissions of the semiconductor nanocrystals. CdSe/ZnS core/shell colloidal nanocrystals with 2.1nm in diameter and emission peak at 515nm were examined. PL spectrum in the solution indicates that besides the band-edge emission, there is a broadband emission spanning the wavelength range of 590 ¡V 800 nm, which is called the red-emission. The lifetime of the band-edge emission is about 20ns, and that of the red-emission is about 200ns. Since they are with different fluorescence lifetime, the band-edge emission and the red-emission are from distinct emission species. Emission intensity from individual QDs of the band-edge emission and the red-emission are recorded by an imaging CCD. Most QDs exhibit band-edge emission. Only few QDs show the red-emission. Both emissions exhibit clear on-off blinking, indicating the two phenomena are with different mechanism.Moreover, the band-edge emission and the red-emission are mutual exclusive.None QDs exhibit both emissions. This indicates the tiny structure difference from one QD particle to another QD particle resulting in a dramatic different of the excitation energy relaxation pathway.
4

Cerebellar control of classical conditioning

Ivarsson, Magnus. January 1998 (has links)
Thesis (doctoral)--Lund University, 1998. / Added t.p. with thesis statement inserted. Includes bibliographical references.
5

Exploration of the crosslinks between saccadic and vergence eye movement pathways using motor and visual perturbations

Schultz, Kevin P. January 2010 (has links) (PDF)
Thesis (Ph.D.)--University of Alabama at Birmingham, 2010. / Title from PDF title page (viewed on July 8, 2010). Includes bibliographical references (p.169-183).
6

Cerebellar control of classical conditioning

Ivarsson, Magnus. January 1998 (has links)
Thesis (doctoral)--Lund University, 1998. / Added t.p. with thesis statement inserted. Includes bibliographical references.
7

Blinking in human communicative behaviour and its reproduction in artificial agents

Ford, Christopher Colin January 2014 (has links)
A significant year-on-year rise in the creation and sales of personal and domestic robotic systems and the development of online embodied communicative agents (ECAs) has in parallel seen an increase in end-users from the public domain interacting with these systems. A number of these robotic/ECA systems are defined as social, whereby they are physically designed to resemble the bodily structure of a human and behaviorally designed to exist within human social surroundings. Their behavioural design is especially important with respect to communication as it is commonly stated that for any social robotic/ECA system to be truly useful within its role, it will need to be able to effectively communicate with its human users. Currently however, the act of a human user instructing a social robotic/ECA system to perform a task highlights many areas of contention in human communication understanding. Commonly, social robotic/ECA systems are embedded with either non-human-like communication interfaces or deficient imitative human communication interfaces, neither of which reach the levels of communicative interaction expected by human users, leading to communication difficulties which in turn create negative association with the social robotic/ECA system in its users. These communication issues lead to a strong requirement for the development of more effective imitative human communication behaviours within these systems. This thesis presents findings from our research into human non-verbal facial behaviour in communication. The objective of the work was to improve communication grounding between social robotic/ECA systems and their human users through the conceptual design of a computational system of human non-verbal facial behaviour (which in human-human communicative behaviour is shown to carry in the range of 55% of the intended semantic meaning of a transferred message) and the development of a highly accurate computational model of human blink behaviour and a computational model of physiological saccadic eye movement in human-human communication, enriching the human-like properties of the facial non-verbal communicative feedback expressed by the social robotic/ECA system. An enhanced level of interaction would likely be achieved, leading to increased empathic response from the user and an improved chance of a satisfactory communicative conclusion to a user’s task requirement instructions. The initial focus of the work was in the capture, transcription and analysis of common human non-verbal facial behavioural traits within human-human communication, linked to the expression of mental communicative states of understanding, uncertainty, misunderstanding and thought. Facial Non-Verbal behaviour data was collected and transcribed from twelve participants (six female) through a dialogue-based communicative interaction. A further focus was the analysis of blink co-occurrence with other traits of human-human communicative non-verbal facial behaviour and the capture of saccadic eye movement at common proxemic distances. From these data analysis tasks, the computational models of human blink behaviour and saccadic eye movement behaviour whilst listening / speaking within human-human communication were designed and then implemented within the LightHead social robotic system. Human-based studies on the perception of naïve users of the imitative probabilistic computational blink model performance on the LightHead robotic system are presented and the results discussed. The thesis concludes on the impact of the work along with suggestions for further studies towards the improvement of the important task of achieving seamless interactive communication between social robotic/ECA systems and their human users.
8

Relação entre as alterações do piscar espontâneo e a superfície ocular em hansenianos / Spontaneous eyeblink changes and ocular surface in leprosy

Bertrand, Adriana Leite Xavier 30 May 2016 (has links)
A prevalência mundial da hanseníase vem demonstrando redução no número de casos, porém, no Brasil e em alguns países, ela ainda representa um grave problema de saúde pública, podendo levar a incapacidades funcionais graves como a cegueira. O objetivo do estudo foi avaliar a relação entre as alterações do piscar e a superfície ocular em hansenianos. Todos os pacientes estudados foram submetidos à mesma anamnese e avaliação oftalmológica: acuidade visual, ectoscopia, biomicroscopia, avaliação da superfície ocular, teste da graduação da força muscular do orbicular, sensibilidade corneana, distância da margem reflexa, medida da pressão intraocular e mensuração do piscar espontâneo palpebral por meio de um método de imagem por vídeo. Dos 56 pacientes examinados, 69,6% eram do sexo masculino, com média de idade de 55,96 ± 16,63 dp, 46,4% se declararam negros e 28,55% pardos, 71,4% apresentavam a forma multibacilar e 73,2% estavam fora do registro ativo da doença. Desses 56 pacientes, 43 apresentaram significativa simetria interocular no acometimento do nervo facial e do trigêmeo (p=0,11), o que foi corroborado pela alta correlação entre as medidas da amplitude do piscar entre os olhos (r=0,90). Apenas 12,5% apresentaram tempo de ruptura do filme lacrimal menor que 10 segundos e em um paciente este foi menor que 5. Evidenciou-se sofrimento da superfície ocular em cerca de 14% dos olhos. As alterações de sensibilidade foram mais prevalentes, pois 51,8% apresentaram algum grau de diminuição. A média geral da taxa do piscar foi de 17,0 ± 2,6 blink/min. De acordo com o exame de Lissamina, observou-se taxa média de 16,0 ± 2,8 (média±dp) para os pacientes com resultado negativo e 23,2 ± 6,8 para os com resultado positivo (t=0,961; p=0,3407); e em relação à sensibilidade corneana, as taxas médias foram 14,6 ± 3,8 e 19,2 ± 3,6 para os pacientes com resposta imediata e alterada, respectivamente (t=0,875; p=0,3857). De acordo com o tônus muscular, a média das taxas do piscar para os pacientes normais e alterados não foi significativa (t=0,539; p=0,592). Apesar do número e da amplitude dos movimentos serem diferentes, a main sequence demonstrou comportamento linear em todos os casos, sendo a média geral 20,25 ± 6,9 (0,94 ep). As médias da taxa, amplitude e efetividade do piscar em pacientes com função do músculo orbicular do olho normal e naqueles com função alterada não demonstraram diferença estatística, já a média da velocidade máxima do piscar com função normal foi de 115,5 ± 47,2 mm/s, enquanto que naqueles com lagoftalmo foi 67,7 ± 27 (t=2,08; p=0,04) e a média do deslocamento horizontal de 2,1 ± 0,7 mm e 0,9 ± 0,8 mm, respectivamente (t=1,99; p=0,05). Embora os pacientes hansenianos não apresentem taxa de piscar diferente do normal, demonstram tendência à diminuição da velocidade e do deslocamento horizontal quando apresentam alterações da função do músculo orbicular. A maioria dos pacientes apresentou alteração de sensibilidade corneana, porém, sem sinais de sofrimento da superfície ocular, principalmente com a cinemática palpebral preservada. / Global prevalence of leprosy has demonstrated a reduction in the number of cases, however, in Brazil and some countries, it still represents a serious public health problem, often leading to severe functional disabilities such as blindness for example. This study aimed to evaluate the relationship between blink and ocular surface in patients with leprosy. Leprosy patients underwent the same history and ophthalmologic evaluation: visual acuity, ectoscopy, slit lamp examination, evaluation of ocular surface, test the eyelid function and the degree of orbicularis function, corneal sensitivity, margin reflex distance, measured intraocular pressure and measuring eyelid spontaneous blinking through an image video system. 69.6% were male, with a mean age of 55.96 ± 16.63 SD. 46.4% declared themselves as black and brown were 28.55%, 71.4% were multibacillary and 73.2% were out of active disease registry. Between the 56 patients examined, 43 of those had significant interocular symmetry of the involvement of the facial and the trigeminal nerves (p=0.11), which was confirmed by the high correlation between the measurements of amplitude flashing of the eyes (r=0,90). Only 12.5% had TFRL was under 10 seconds and in one patient it was under 5 seconds. It was evidenced suffering from ocular surface in about 14% of the eyes. Sensitivity changes were more prevalent, 51.8% had some degree of impairment. Overall average blink rate was 17.0 ± 2.6 blinks/min. In the lissamine test, we observed an average rate of 16.0 ± 2.8 for patients with negative and 23.2 ± 6.8 for a positive result (t=0.961, p=0.3407). The mean values were 14.6 ± 3.8 (mean ± SD) and 19.2 ± 3.6 for for patients with immediate corneal sensitivity response and altered response, respectively (t=0.875, p=0.3857). According muscle tone, mean blink rates for normals and for injured patients, were not different (t=0.539, p=0.592). Although the number and range of motion are different, the main sequence had a linear behavior in all cases, with an overall mean 20.25 ± 6.9 (p 0.94). The mean blink rate, amplitude and effectiveness in patients with normal orbicularis function and those with altered function, showed no statistical diference, while the mean of maximum velocity blink was, with normal function, 115.5 ± 47.2 mm/s, while those with lagophthalmos was 27 ± 67.7 (t=2.08, p=0.04) and the mean horizontal displacement was 2.1 ± 0.7 mm and 0.9 ±0.8 mm respectively (t=1.99, p=0.05). Although leprosy patients do not have a different flash rate of the normal population, blinking characteristics show a tendency to decrease in speed and horizontal scrolling when they show important changes in orbicularis function. The vast majority of patients had corneal sensitivity changes, but without signs of ocular surface suffering, especially those with eyelid kinematics preserved.
9

Cellular Neural Networks with Switching Connections

Devoe, Malcom, Devoe, Malcom W, Jr. 06 May 2012 (has links)
Artificial neural networks are widely used for parallel processing of data analysis and visual information. The most prominent example of artificial neural networks is a cellular neural network (CNN), composed from two-dimensional arrays of simple first-order dynamical systems (“cells”) that are interconnected by wires. The information, to be processed by a CNN, represents the initial state of the network, and the parallel information processing is performed by converging to one of the stable spatial equilibrium states of the multi-stable CNN. This thesis studies a specific type of CNNs designed to perform the winner-take-all function of finding the largest among the n numbers, using the network dynamics. In a wider context, this amounts to automatically detecting a target spot in the given visual picture. The research, reported in this thesis, demonstrates that the addition of fast on-off switching (blinking) connections significantly improves the functionality of winner-take-all CNNs. Numerical calculations are performed to reveal the dependence of the probability, that the CNN correctly classifies the largest number, on the switching frequency.
10

Nanocompósito de óxido de grafeno e nanopartículas metálicas para espectroscopia raman amplificada por superfície (SERS)

Vianna, Pilar Gregory 24 January 2017 (has links)
Submitted by Rosa Assis (rosa_assis@yahoo.com.br) on 2017-09-21T13:40:28Z No. of bitstreams: 2 PILAR GREGORY VIANNA.pdf: 4126013 bytes, checksum: c4320ab5ecb2ec5dfc641f96b6c6fa51 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Paola Damato (repositorio@mackenzie.br) on 2017-09-22T13:35:43Z (GMT) No. of bitstreams: 2 PILAR GREGORY VIANNA.pdf: 4126013 bytes, checksum: c4320ab5ecb2ec5dfc641f96b6c6fa51 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-09-22T13:35:43Z (GMT). No. of bitstreams: 2 PILAR GREGORY VIANNA.pdf: 4126013 bytes, checksum: c4320ab5ecb2ec5dfc641f96b6c6fa51 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-01-24 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Fundação de Amparo a Ciência e Tecnologia / Fundo Mackenzie de Pesquisa / Light interaction with the electronic cloud of metallic nanoparticles at frequencies that are resonant with the natural oscillation frequency of the cloud is known to excite localized surface plasmons. This phenomenon is widely used to enhance the Raman signal, known to have small cross sections. The technique, known as surface-enhanced Raman spectroscopy (SERS), enables the detection of chemical and biological species with high sensitivity. However, charge transfer mechanisms, adsorption/desorption and changes in the substrate morphology induce temporal instability of the SERS signal, known as blinking, which is an obstacle to the precise detection of the molecules under analysis. In this work, we, therefore, propose a SERS substrate composed of graphene oxide and gold nanorods, capable of suppressing the temporal fluctuations in the intensity of the spectrum. Temporal stability is statistically determined by the coefficient of variation of the integrated spectra, from which it is verified that, with the addition of graphene oxide, the nanocomposite is five times more stable than with gold nanorods only. The stability improvement is attributed to the removal of the nanorods’ surfactant from plasmonic hot spots due to graphene oxide-surfactant interaction. Thus, the nanocomposite is used as a reliable SERS substrate in the detection of Rhodamine 640. The analysis indicates a Rodamine detection that is four times more stable with the nanocomposite, than without graphene oxide. The nanocomposite is then used for the coating of the inner surface of microcapillaries. Graphene oxide and gold nanorod suspensions are subsequently used to fill the capillaries, with a drying step for the evaporation of solvents in between each filling stage. The continuous coating of the capillary fibers with the nanocomposite is verified by Raman spectroscopy, and Rhodamine 640 is used as a probe molecule, this time inside the capillaries, for SERS analysis. The microcapillaries allow for the use of small amounts of sample, and smaller concentrations than those detected with other reported optofluidic substrates are measured. / A interação da luz com a nuvem eletrônica de nanopartículas metálicas em frequências que apresentam ressonância com a frequência natural de oscilação da nuvem é conhecida por gerar a excitação de plásmons localizados de superfície. Este efeito é amplamente utilizado na amplificação do sinal Raman, conhecido por possuir baixas seções de choque. A técnica, conhecida como espectroscopia Raman amplificada por superfície (SERS), possibilita a detecção de espécies químicas e biológicas com altíssima sensibilidade. Entretanto, mecanismos de troca de carga, adsorção/dessorção e alterações na morfologia do substrato induzem uma instabilidade temporal do sinal SERS, fenômeno conhecido como blinking, que é um obstáculo na detecção precisa das moléculas em análise. Neste trabalho, propomos, portanto, um substrato SERS composto de óxido de grafeno e nanobastões de ouro, capaz de suprimir as flutuações temporais na intensidade do espectro. A estabilidade temporal é estatisticamente determinada pelo coeficiente de variação da integral do espectro, de onde verifica-se que com a adição de óxido de grafeno, o nanocompósito apresenta estabilidade cinco vezes superior comparado à detecção com nanobastões de ouro somente. A melhoria na estabilidade é atribuída à remoção do surfactante dos nanobastões dos hot spots, o que ocorre devido à interação óxido de grafeno-surfactante. Assim, o nanocompósito é utilizado como um substrato SERS confiável na detecção de Rodamina 640. A análise aponta para uma detecção quatro vezes mais estável da Rodamina no nanocompósito comparada ao sinal proveniente da molécula em nanobastões sem óxido de grafeno. O nanocomposito é, então, utilizado no revestimento das paredes internas de microcapilares para detecção SERS optofluídica. Para isso, suspensões de óxido de grafeno e de nanobastões de ouro eram subsequentemente utilizadas para preencher os capilares, com secagem por evaporação dos solventes entre as etapas de preenchimento. Verifica-se o revestimento contínuo das fibras capilares com o nanocompósito por espectroscopia Raman, e Rodamina 640 é utilizada como mólecula de prova, dessa vez introduzida no interior dos capilares para análises de SERS. Os microcapilares permitem a utilização de pequenas quantidades de amostra, e concentrações inferiores àquelas detectadas com outros substratos optofluídicos reportados na literatura são medidas.

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