Dissertations / Theses on the topic 'Behavioral oscillations'
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Chen, Danjue. "Studies of traffic oscillations: a behavioral perspective." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/48975.
Full textSiegle, Joshua H. (Joshua Hangman). "Causal evidence for the behavioral impact of oscillations in neocortex and hippocampus." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/95857.
Full textCataloged from PDF version of thesis.
Includes bibliographical references.
Neuroscientists hold widely divergent opinions on the behavioral relevance of oscillatory brain states. Some consider them to be a side effect of anatomical connectivity, with little or no role in guiding action. Others view them as a fundamental feature of the network states that underlie perception and cognition. In this thesis, I take a systematic approach to studying two of the most prominent types of oscillations,'gamma rhythms in the neocortex (30-80 Hz) and theta rhythms in the hippocampus (4-12 Hz). In both cases, I use light-gated ion channels to manipulate spike activity on a cycle-by-cycle basis in awake, behaving mice. By rhythmically stimulating fast-spiking interneurons in somatosensory cortex, I can emulate the activity patterns that define gamma oscillations under natural conditions. Emulating gamma enhances the detection of threshold-level vibrissae deflections, analogous to the behavioral effects of shifting attention. By triggering stimulation of fast-spiking interneurons in the hippocampus on peaks and troughs of endogenous rhythms, I can reduce spike activity at specific phases of theta. In the context of a spatial navigation task, I find that the ability of inhibition to enhance decision-making accuracy depends on both the theta phase and the task segment in which it occurs. Both of these experiments provide novel causal evidence for the behavioral impact of oscillations, which offers a much more compelling argument for their utility than traditional correlative measures. Finally, I present a new platform for extracellular electrophysiology. This platform, called Open Ephys, makes the closed-loop experiments that are ideal for studying oscillations accessible to a wider audience.
by Joshua H. Siegle.
Ph. D.
Cicchese, Joseph John. "Theta Oscillations Modulate Hippocampal Single-Unit Responses Across Subregions During Trace Eyeblink Classical Conditioning." Miami University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=miami1466187297.
Full textHadzibegovic, Senka. "Behavioral, molecular and electrophysiological characterization of the learning and memory deficits induced in mouse models of Alzheimer’s disease." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0151/document.
Full textCognitive impairments in Alzheimer’s disease (AD) are thought to be related to degenerative synaptic changes caused by the accumulation of amyloid-β peptides (Aβs) in vulnerable brain regions such as the hippocampus. At the molecular level, Aβs bind preferentially to the postsynaptic density of neuronal excitatory synapses, where the scaffolding post-synaptic protein-95 (PSD-95) organizes NMDA receptor (NMDAR) location as well as its downstream signaling. By using an integrative strategy which favoured vertical levels of analyses (from phenotype to molecular events) and combined a set of interrelated correlative and invasive approaches in a double transgenic mouse model of AD (APPswe/PS1dE9 mice), we were successful in establishing that Aβs destabilize the synaptic organization (reduction of expression of PSD-95) and increase the extrasynaptic pool of GluN2B-containing NMDAR in the hippocampus, a reorganization which translates into impaired memory functions. It is also well-known that hippocampal sharp wave-ripples (SWRs) generated during sleep periods are crucial for memory formation but accumulation of soluble Aβs, surprisingly seems to spare SWR dynamics during routine behavior. To unravel a potential effect of Aβs on SWRs in cognitively-challenged animals, we submitted vehicle- and Aβ-injected mice to spatial recognition memory testing. While capable of forming short-term memory, Aβ mice exhibited faster forgetting, suggesting successful encoding but an inability to adequately stabilize and/or retrieve previously acquired information. Without prior cognitive requirements, similar properties of SWRs were observed in both groups. In contrast, when cognitively challenged, the post-encoding and -recognition peaks in SWR occurrence observed in controls were abolished in Aβ mice, indicating impaired hippocampal processing of spatial information. Altogether these results identify two new disruptive mechanisms for the spatial memory deficits associated with AD
Rabiller, Gratianne. "Contribution of hippocampal diaschisis to the memory deficits associated with focal cerebral ischemia in the rat : converging behavioral, electrophysiological and functional evidence." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0461/document.
Full textThe cognitive consequences and the underlying mechanisms leading to cognitive impairments after cerebrovascular occlusive diseases are still unclear. In addition to the infarct zone that suffer the deadly consequence of ischemic stroke, the penumbra surrounding the lesion site and some brain regions more remote to the ischemic areas can be functionally affected by the insult. This phenomenon is referred to as diaschisis. In light of the importance of interactions between hippocampus and cortex during memory processing, we hypothesized that the cognitive impairments observed following focal ischemia could occur in the absence of direct hippocampal insult, possibly via impaired connectivity within cortico-hippocampal networks leading to diaschisis-induced hypofunctioning in specific hippocampal subregions. To examine this possibility, we used the distal middle cerebral artery occlusion (dMCAO) ischemic model in rats which induces restricted cortical infarct in the somatosensory (SS) cortex in the absence of direct hippocampal injury. dMCAO rats exhibited reduced expression of the activity-dependent gene c-fos in the hippocampus when exploring a novel environment, indicating neuronal hypoactivation. Ischemic rats also showed impaired associative olfactory and spatial memory when tested in the social transmission of food preference (STFP) task and the Barnes maze test, respectively. To confirm that the ischemic-induced hippocampal hypofunctioning resulted from reduced afferent inputs (i.e. deactivation) originating in the damaged cortex, we performed region-specific pharmacological inactivation of SS and/or HPC using lidocaine or CNQX. Fos imaging revealed that these treatments induced hippocampal hypoactivation and impaired memory performance as measured in the STFP task. We additionally performed electrophysiological recordings of hippocampal activity in anesthetized rats during acute stroke and two weeks later or after SS cortex inactivation. We found an alteration in the occurrence of sharp-wave ripples associated with instability of theta frequency during reperfusion after stroke and SS cortex inactivation, suggesting an alteration in the dynamics of hippocampal-cortical interactions. Taken collectively, these findings identify hippocampal diaschisis as a crucial mechanism for mediating stroke-induced hippocampal hypofunction and associated memory deficits
Aravamuthan, Bhooma Rajagopalan. "Comparing the radiological anatomy, electrophysiology, and behavioral roles of the pedunculopontine and subthalamic nuclei in the normal and parkinsonian brain." Thesis, University of Oxford, 2008. http://ora.ox.ac.uk/objects/uuid:9a735b39-c1fe-4d5f-b05f-3385f27e6e58.
Full textSchumann, Michael. "Nonlinear dynamics in oscillating waterfalls." PDXScholar, 1992. https://pdxscholar.library.pdx.edu/open_access_etds/4421.
Full textZhang, Huihui. "Temporal dependence in perceptual decision-making: behavioural oscillations and sequential effects." Thesis, The University of Sydney, 2019. http://hdl.handle.net/2123/20847.
Full textIachello, Marco. "Nonlinear oscillations in high power systems." Doctoral thesis, Università di Catania, 2015. http://hdl.handle.net/10761/3913.
Full textFeingold, Joseph. "Beta oscillations in frontal cortex and striatum represent post-processing of successful behavior." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/68453.
Full textCataloged from PDF version of thesis.
Includes bibliographical references.
Beta band (13-30 Hz) oscillations in sensorimotor cortex are associated with motor performance, but the nature of this relationship is not clear. Recently, excessive beta activity in cortico-basal ganglia circuits has been recognized as a hallmark of Parkinson's disease. Renewed interest in beta oscillations has since led to the suggestion that they might reflect the preservation of the current output or state of a given brain region. To investigate the potential role of beta activity in the brain, we recorded local field potentials in the frontal cortex and striatum of monkeys as they performed single and sequential arm movement tasks. To facilitate these experiments, we developed novel methods for recording simultaneously from independently moveable electrodes implanted chronically at over 100 sites in cortical and subcortical areas of the monkey brain. We found that, across tasks, beta oscillations occurred in brief, spatially localized bursts that were most prominent following task performance. Across brain regions, post-performance bursts were differentially modulated by the preceding task. In motor cortex they tracked the number of movements just performed. In contrast, striatal and prefrontal burst rates were proportional to the number of visual cues, or to a combination of the cues and movements, respectively, and were higher following correct, rewarded, trials than unrewarded errors. Pairs of striatal-prefrontal sites exhibited increased cross-covariance and coherence during post-trial beta bursts, suggesting that these bursts might be involved in communication or coordination across brain regions. Based on our results, we propose that beta oscillations may represent post-performance reinforcement of the network dynamics that led to the desired behavioral outcome obtained immediately prior.
by Joseph Feingold.
Ph.D.
Piskun, Nikolay. "Auto-oscillation's behavior in YIG films from the stability point of view /." The Ohio State University, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488193272066689.
Full textKolomiyets, Yuriy V. "Asymptotic Behavior of Randomly Perturbed Dynamical Systems." Kent State University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=kent1164124028.
Full textDong, Yan. "Performance and Oscillation Behavior of PBI-Phosphoric Acid based Higher-Temperature Vapor Feed Direct Methanol Fuel Cells." Digital WPI, 2015. https://digitalcommons.wpi.edu/etd-theses/505.
Full textMühlberg, Stefanie 1986. "Selective deployment of attention to time and modality and its impact upon behavior and brain oscillations." Doctoral thesis, Universitat Pompeu Fabra, 2016. http://hdl.handle.net/10803/392142.
Full textEsta tesis investiga la relación entre la atención al tiempo y a la modalidad al nivel de comportamiento y oscilaciones cerebrales pre-estímulo. En los estudios que se presentan aquí, los participantes debían responder a estímulos que se presentaban en una de dos modalidades distintas, y podían aparecer en uno de dos momentos distintos. Los factores de tiempo y modalidad fueron entrelazados el uno con el otro a través la manipulación de su probabilidad, según la cual una modalidad era más probable en un momento u otro y una de las modalidades era más probable en general. Los resultados mostraron que la atención a cada modalidad seguía su respectiva probabilidad temporal, independientemente de la combinación de modalidades, lo cual sugiere un mecanismo general para el desacoplamiento inter-sensorial en la atención temporal. Este resultado es interesante porque contrasta con la atención inter-sensorial en el dominio espacial, donde las distintas modalidades parecen funcionar de manera acoplada. El efecto de desacoplamiento en atención temporal también parece modular las oscilaciones cerebrales antes del momento en anticipación al estímulo, en bandas de frecuencia distintas. Según los resultados obtenidos mediante el registro de estas oscilaciones, elaboramos las siguientes hipótesis: las oscilaciones alfa parecen codificar expectativas sobre cambios de modalidad en las cortezas sensoriales, mientras que la banda beta parece codificar las expectativas sobre la modalidad del siguiente estímulo, y el efecto de atención temporal en sí.
Fogelson, Noa. "Oscillations in the basal ganglia in Parkinson's disease patients and their influence on the cerebral cortex and behavioural performance." Thesis, University College London (University of London), 2005. http://discovery.ucl.ac.uk/1445455/.
Full textNakamura, Hideo. "The effect of beam oscillation rate on Al evaporation behavior in the electron beam melting process." Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/27944.
Full textApplied Science, Faculty of
Materials Engineering, Department of
Graduate
Benz, Rafael Franzon. "Salicylate generates anxiety-like behavior and type 2 theta oscillation in the ventral hippocampus of mice." PROGRAMA DE P?S-GRADUA??O EM NEUROCI?NCIAS, 2016. https://repositorio.ufrn.br/jspui/handle/123456789/22634.
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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)
Salicilato, o principal composto de diversos medicamentos, como a Aspirina, ? conhecido por causar zumbido se consumido em altas doses ou de forma cr?nica (para o tratamento de osteoporose, por exemplo). Zumbido ? o ouvir ou a percep??o de um som quando nenhum est?mulo f?sico est? presente. O zumbido n?o ? uma doen?a em si, mas um sintoma presente em diversas doen?as, e est? associado ? ansiedade e outros dist?rbios de humor. Apesar de estar diretamente ligado ao sistema auditivo, o zumbido n?o ? gerado a partir de uma regi?o espec?fica do c?rebro. Al?m disso, alguns estudos mostraram que o salicilato afeta v?rias regi?es cerebrais al?m do sistema auditivo, como o estriado, amigdala e o hipocampo. Estudos iniciais atribu?ram uma fun??o unit?ria ao hipocampo: processamento de memorias declarativas. Entretanto, estudos mais recentes mostraram que o hipocampo n?o s? possui outras fun??es, como processamento emocional, mas tamb?m pode ser dividido em ventral e dorsal, e a parte ventral desempenha um papel essencial no processamento emocional. A oscila??o mais estudada do c?rebro ? o r?tmo teta, e ela pode ser encontrada em todo o hipocampo. Dois tipos de teta podem ser distinguidos: o teta tipo 1, que ? resistente a atropina, possui uma frequ?ncia mais alta (7 a 10 Hz) e est? relacionado com comportamentos de padr?o motor; e o teta tipo 2, que ? sens?vel a atropina, possui uma frequ?ncia mais baixa (4 to 7 Hz) e ocorre durante anestesia, estado de imobilidade vigilante e situa??es de alta ansiedade. O presente estudo investigou os efeitos eletrofisiol?gicos do salicilato no hipocampo ventral de camundongos em estado de comportamento. Atrav?s da inje??o de salicilato foi gerado teta tipo 2 no hipocampo ventral. Tamb?m foi encontrado que o salicilato leva a comportamentos de ansiedade.
Salicylate, the main compound of many medications as Aspirin, is known to cause tinnitus if consumed in high doses or in a chronic way (for the treatment of osteoporosis, for example). Tinnitus is the hearing or perception of a sound when no physical stimulus is present. Tinnitus is not a disease itself, but a symptom present in some diseases, and is associated with anxiety and other mood disorders. Despite being directly related with auditory system, tinnitus is not generated from one specific region of the brain. Additionally, some studies showed that salicylate affects various brain regions besides the auditory system, as the striatum, amygdala and the hippocampus. Early studies have ascribed a unitary function to the hippocampus: declarative memory processing. However, more recent studies showed that the hippocampus not only has other functions, as emotional processing, but also can be divided into ventral and dorsal, and the ventral part plays an essential role in emotional processing. The most studied oscillation of the brain is the theta rhythm, and it can be found in the entire hippocampus. Two types of theta can be distinguished: the type 1, that is atropine resistant, has a higher frequency (7 to 10 Hz) and is related with motor pattern behaviors; and the type 2 theta, that is atropine sensitive, has a lower frequency (4 to 7 Hz) and occur during anesthesia, alert immobility and high arousal situations. The present study investigated the electrophysiological effects of salicylate in the ventral hippocampus of behaving mice. Through salicylate injection we generated type 2 theta in the ventral hippocampus. We also found that salicylate led to anxietylike behavior
Sharma, Arvindh R. "Liquid Jet in Oscillating Crossflow: Characterization of Near-Field and Far-Field Spray Behavior." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1439281517.
Full textAndersson, Jonathan. "Asymptotic behavior and effective boundaries forage-structured population models in aperiodically changing environment." Thesis, Linköpings universitet, Matematik och tillämpad matematik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-133632.
Full textFelts, K. R. Chicone Carmen Charles. "Oscillators resonances and excitations /." Diss., Columbia, Mo. : University of Missouri--Columbia, 2009. http://hdl.handle.net/10355/6147.
Full textMert, Raziye. "Qualitative Behavior Of Solutions Of Dynamic Equations On Time Scales." Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/3/12611528/index.pdf.
Full textToyoda, Aru. "Studies on male mating strategy, reproductive success, and copulation related behaviors of stump-tailed macaques in Khao Krapuk Khao Taomor Non-Hunting Area, Thailand." Kyoto University, 2018. http://hdl.handle.net/2433/235054.
Full textCarus-Cadavieco, Marta. "Coordination of innate behaviors by GABAergic cells in lateral hypothalamus." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19135.
Full textLateral hypothalamus (LH) is crucial for regulation of innate behaviors. However, it remained unknown whether and how temporal coordination of hypothalamic neuronal populations regulates behavioral transitions. This work combined optogenetics with neuronal recordings in behaving mice. LHVgat cells were optogenetically identified. LHVgat neurons increased firing rates upon transitions from non-REM (NREM) sleep to wakefulness, and their optogenetic stimulation during NREM sleep induced a fast transition to wakefulness. LHVgat cells project to the reticular thalamic nucleus (RTN). Optogenetic activation of LHVgat terminals in the RTN exerted a strong frequency-dependent inhibition of RTN cells and replicated state-dependent changes in RTN neurons activity. Recordings of LH neurons during exploration revealed that 65% of LH neurons increased their activity upon the onset of locomotion. Top-down forebrain innervation of LH is provided, to a great extent, by inhibitory inputs from the lateral septum (LS). During spontaneous exploration in a free-feeding model, LS and LH displayed prominent gamma oscillations (30-90 Hz) which entrained neuronal activity within and across the two regions. Optogenetic gamma-frequency stimulation of somatostatin-positive GABAergic projections to LH facilitated food-seeking, and increased the probability of entering the food zone. LS inhibitory input enabled separate signaling by LH neurons according to their feeding-related activity, making them fire at distinct phases of the gamma oscillation. In contrast to increased food intake during optogenetic stimulation of LHVgat cells, food intake during gamma-rhythmic LS-LH stimulation was not changed. Overall this works provides new insight into the function of LH circuitry, that employs signalling at different time scales, which, in coordination with upstream and downstream circuits, regulates transitions between innate behaviors.
Sokoliuk, Rodika. "From alpha to perception : investigating behavior and brain activity." Toulouse 3, 2014. http://thesesups.ups-tlse.fr/2353/.
Full textIt has been suggested that visual perception is organized in discrete snapshots relying on an oscillatory brain rhythm of about 10Hz. Even though, in normal conditions, our visual percept seems continuous to us, we show that a specific static stimulus pattern can lead to disruption of this continuity and uncover cycles of alpha oscillations (~10Hz) underlying visual perception. This 'Flickering Wheel Illusion' produces a regular illusory flicker recurring every ~100ms thus at one phase of the alpha cycle. According to previous work, specific phases of occipital alpha (and also fronto-central theta) oscillations are designated as 'inhibitory' for visual processing whereas opposite phases increase probability to detect visual stimuli. In a psychophysical experiment, we analyzed how this temporal phase-detection relationship is organized spatially in the visual cortex. We therefore entrained alpha oscillations with a specific spatial origin and probed visual detection of low-threshold targets at different spatial positions. Detection performance was modulated by the entrained oscillation at all target locations, showing maxima at different phases of the oscillation. We could show that the phase of the entrained alpha oscillations propagated over space like a traveling wave that could implicate important functional roles for sensory processing. Besides its influence on cognitive processes like visual perception, the phase of low frequency oscillations can also modulate the amplitude of fast oscillations (phase-amplitude cross-frequency coupling; PAC). In another experiment, we could reveal PAC between alpha and gamma oscillations during the resting state, what we referred to as pulsed inhibition, illustrating the alpha rhythm as a control mechanism of sensory processing. Alpha oscillations would thus provide specific moments, or phases that enhance gamma amplitude and thus sensory processing, whereas opposite phases would inhibit sensory processing. Moreover, we found a robust PAC between theta and beta oscillations which was also present during a visual detection task. This PAC could help maintaining a specific activity state of the brain. Finally, we could reveal PAC between theta and gamma oscillations in mainly fronto-central regions, influencing visual perception in the detection task but only within the focus of attention. This result is consistent with and complements previous findings of our group showing the influence of the phase of theta oscillations on visual perception. This work contributed to the findings of the important role of ongoing oscillations in visual perception, using multiple experimental approaches; yet our promising results uncovered new questions in this large field of research
Samarbakhsh, Sina. "Investigation of the Lock-in behavior of an eccentrically rotating cylinder in regard to turbomachinery application." Thesis, KTH, Kraft- och värmeteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-154358.
Full textTremouilhac, Pierre. "Orientational behavior of the antimicrobial peptide PGLa in a lipid membrane environment studied by solid-state 2H-NMR spectroscopy Calibration of new flavor tagging algorithms using Bs oscillations /." [S.l. : s.n.], 2007. http://digbib.ubka.uni-karlsruhe.de/volltexte/1000007219.
Full textAhmed, Hafiz. "Modeling and synchronization of biological rhythms : from cells to oyster behavior." Thesis, Lille 1, 2016. http://www.theses.fr/2016LIL10129/document.
Full textModeling, analysis and control of oscillations, notably biological rhythms have been studied in this thesis. The thesis is divided into two parts. In part-I, motivated by a practical problem of environmental monitoring of coastal environment, this thesis considers the biological rhythms of oysters. Using the information of biological rhythms, an indirect environmental monitoring solution using oysters as bio-sensor has been proposed. The proposed solution works on estimating the perturbation by modeling the biological rhythm of oysters through Van der Pol oscillator model. An inherent limit of this approach is that it works through detecting abnormal behavior only. However abnormal behaviors are not all related to pollution. So, we consider the detection of a particular type of abnormal oscillatory behavior i.e. spawning (behavior during reproduction) which is a natural phenomenon and not related to pollution. In part-II, oscillations are studied from a theoretical point of view. The first problem of this part is the robustness of oscillations under cell division. Oscillations persist in genetic oscillators after cell division. In this thesis, we provide analytical conditions that guarantee phase synchronization after cell division using Phase Response Curve (PRC) formalism. Finally we consider the problem of synchronization of multi-stable systems using Input-to-State (ISS) stability tool. Using a recent generalization of ISS theory for multi-stable systems, we propose sufficient conditions for the synchronization of multi-stable systems. As a side result, this work has been applied for the global synchronization of the Brockett oscillator
Yusuf, Solieman Osama. "CAD-CAM ceramic veneers : tooth preparation status, accuracy of Intra Oral Scanner and mechanical behavior." Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTT044/document.
Full textThe first chapter of the thesis relieved the dentists from thinking a lot about the produced roughness regardless to the preparation tool. The roughness is a critical factor to the stability, to the retention, and eventually to the success of the ceramic veneers especially for the esthetic anterior veneers. This will speed up the procedure of achieving a fast treatment for the patients with the CAD-CAM systems. For the upcoming steps, an investigation is recommended to estimate the amount of the inquired roughness to achieve the minimum necessary adhesion value for the retention of the ceramic veneers, and vice versa, another investigation to evaluate the capability of the preparation tools in transferring the same roughness from the preparation tool grains to the target surface (dentin or enamel).152The second study had filled the gap of how to evaluate the IOS systems regardless to the recent common criteria, and the thesis created a novel measure (noise) to be used. The study asks the dentists to pay attention to other criteria to consider when buying an IOS system regardless to the criteria that already exists and had been directed by the producing companies. The thesis states that the noise increases when the direction of the IOS is changed. More attention should be paid at the transitional lines between the scanned surfaces while designing the digital model. An enhancement is demanded to compensate for (or if possible, to eliminate) this noise
Vezenkov, Stoyan Raykov. "Pharmacological studies on the contribution of the neuropeptide proctolin to the cephalic control of singing behavior in grasshopper Chorthippus biguttulus (L. 1758)." Doctoral thesis, [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=974032557.
Full textDarling, Ryan Daniel. "Single Cell Analysis of Hippocampal Neural Ensembles during Theta-Triggered Eyeblink Classical Conditioning in the Rabbit." Miami University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=miami1225460517.
Full textDolcemascolo, Axel. "Laser à semi-conducteur pour modéliser et contrôler des cellules et des réseaux excitables." Thesis, Université Côte d'Azur (ComUE), 2018. http://www.theses.fr/2018AZUR4208/document.
Full textExcitable systems are everywhere in Nature, and among them the neuron, which responds to an external stimulus with an all-or-none type of response, is often regarded as the most typical example. This excitability behaviour is clearly established as to be one of the underlying operating mechanisms of the nervous system and its analysis in model systems (being them mathematical of physical) can, from one hand, shed some light on the dynamics of neural networks, and from the other, open novel ways for a neuro-mimetic treatment of information. The work presented in this PhD thesis was realized in this perspective. In this dissertation we will consider systems based on semiconductor lasers both for modelling excitable systems or coupled neuromorphic networks and for controlling (in an optogenetic outlook) ionic channels that are involved in the emission of action potentials of neurons in mammals. During the first chapter, we will briefly present the dynamical concepts on which we will build our understanding for the rest of the manuscript. Thereafter, we will describe the context of this work from the point of view of synchronized systems, in particular excitable cells. Finally, we will discuss in this context the applications potential of this work, namely the possibility of using “neuromimetic” photonic systems as a was to treat information. In chapter 2 we will firstly analyse from a theoretical and bibliographical standpoint the excitable character of a laser with coherent injection. Later, we will firstly detail our results, firstly experimental and subsequently numerical and theoretical, on the response of this “neuromimetic” system to perturbations repeated in time. Whereas the simplified mathematical model envisions an integrator behaviour in response to repeated perturbations, we will show that the system often acts as a resonator, thus imparting the remarkable property of being able to emit a single pulse only if it receives two perturbations that are separated by a specific time interval. We will also illustrate how this system can convert perturbations of different intensity in a series of all identical pulses whose number depends on the intensity of the incoming perturbation. In the third chapter we will analyse, first experimentally and later numerically and theoretically, the dynamical behaviour of a network of coupled semiconductor lasers in a slow-fast chaotic regime. We will rely on a previous study documenting that a single such element can present a neuromimetic dynamics (in particular, the emission of chaotic pulses originating from a canard phenomenon). Surprisingly for a system having such a large number of degrees of freedom, we observe a dynamics which seems low dimensional chaotic. We will examine the impact of statistical properties of the selected population on the dynamics, and we will link our experimental and numerical observations to the existence of a slow manifold for the mean field, computable analytically, and towards whom the dynamics converges thanks to the slow-fact nature of the system. Finally, in chapter 4 we will present a short experimental study on the response of biological cells to light perturbations. Indeed, optogenetic techniques enables to render the cells (in particular neurons) sensitive to light due to the optical control of the opening and closing of ionic channels. Hence, after having studied in the previous chapters optical systems on the basis of observations derived from biological systems, we will physically transfer an optical system towards a biological one. Here we lay the groundwork of a photonic system which allows, with a moderate complexity, to realize cell measurements in response to spatially localized optical perturbations
Ossandon, Valdes Tomas. "A prefrontal-temporal network underlying state changes between Stimulus-Driven and Stimulus-Independent Cognition." Phd thesis, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00726306.
Full textDevlin, Adam Thomas. "On the variability of Pacific Ocean tides at seasonal to decadal time scales| Observed vs modelled." Thesis, Portland State University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10128376.
Full textOcean tides worldwide have exhibited secular changes in the past century, simultaneous with a global secular rise in mean sea level (MSL). The combination of these two factors contributes to higher water levels, and may increase threats to coastal regions and populations over the next century. Equally as important as these long-term changes are the short-term fluctuations in sea levels and tidal properties. These fluctuations may interact to yield locally extreme water level events, especially when combined with storm surge. This study, presented in three parts, examines the relationships between tidal anomalies and MSL anomalies on yearly and monthly timescales, with a goal of diagnosing dynamical factors that may influence the long-term evolution of tides in the Pacific Ocean. Correlations between yearly averaged properties are denoted tidal anomaly trends (TATs), and will be used to explore interannual behavior. Correlations of monthly averaged properties are denoted seasonal tidal anomaly trends (STATs), and are used to examine seasonal behavior. Four tidal constituents are analyzed: the two largest semidiurnal (twice daily) constituents, M2 and S2, and the two largest diurnal (once daily) constituents, K1 and O1.
Part I surveys TATs and STATs at 153 Pacific Ocean tide gauges, and discusses regional patterns within the entire Pacific Ocean. TATs with statistically significant relations between MSL and amplitudes (A-TATs) are seen at 89% of all gauges; 92 gauges for M2, 66 for S2, 82 for K1, and 59 for O1. TATs with statistically significant relations between tidal phase (the relative timing of high water of the tide) and MSL (P-TATs) are observed at 55 gauges for M2, 47 for S2, 42 for K1, and 61 for O1. Significant seasonal variations (STATs) are observed at about a third of all gauges, with the largest concentration in Southeast Asia. The effect of combined A-TATs was also considered. At selected stations, observed tidal sensitivity with MSL was extrapolated forward in time to the predicted sea level in 2100. Results suggest that stations with large positive combined A-TATs produce total water levels that are greater than those predicted by an increase in MSL alone, increasing the chances of high-water events.
Part II examines the mechanisms behind the yearly (TAT) variability in the Western Tropical Pacific Ocean. Significant amplitude TATs are found at more than half of 26 gauges for each of the two strongest tidal constituents, K1 (diurnal) and M2 (semidiurnal). For the lesser constituents analyzed (O1 and S2), significant trends are observed at ten gauges.
Part III analyzes the seasonal behavior of tides (STATs) at twenty tide gauges in the Southeast Asian waters, which exhibit variation by 10 – 30% of mean tidal amplitudes. A barotropic ocean tide model that considers the seasonal effects of MSL, stratification, and geostrophic and Ekman velocity is used to explain the observed seasonal variability in tides due to variations in monsoon-influenced climate forcing, with successful results at about half of all gauges. The observed changes in tides are best explained by the influence of non-tidal velocities (geostrophic and Ekman), though the effect of changing stratification is also an important secondary causative mechanism.
From the results of these surveys and investigations, it is concluded that short-term fluctuations in MSL and tidal properties at multiple time scales may be as important in determining the state of future water levels as the long-term trends. Global explanations for the observed tidal behavior have not been found in this study; however, significant regional explanations are found at the yearly time scale in the Solomon Sea, and at the seasonal time scale in Southeast Asia. It is likely that tidal sensitivity to annual and seasonal variations in MSL at other locations also are driven by locally specific processes, rather than factors with basin-wide coherence. (Abstract shortened by ProQuest.)
De, la Cruz Sanchez Carmen Mariella. "Utilisation de conduites de séchage oscillantes pour réduire les contraintes liées au retrait du bois." Thesis, Paris, AgroParisTech, 2012. http://www.theses.fr/2012AGPT0068/document.
Full textWood drying is an essential process in the wood industry. A perfect control of wood drying is nowadays very important for the wood industry. In this study, we propose the utilization of oscillating drying conditions to reduce the drying stresses induced by wood shrinkage by activating the mechanosorptive creep. The best way to apply this concept remains an open question in the scientific community. Beech wood (Fagus sylvatica), one of the most commonly used hardwood in France, was chosen for this study owing its elevated risk of drying defaults. The effect of oscillating conditions on drying stresses inside the boards was studied by both an experimental and a theoretical approach, structured in three parts: - A first experimental part realized with a semi – industrial kiln in order to study the global effect of oscillating conditions at the stack scale. Improvement of the quality of dried wood was showed by the best homogeneity of water content inside the board and among the boards and by the decrease of global deformations and residual stresses expressed by the gap measured by the slicing test. - The study was continued with a theoretical part based on analytical and numerical modeling to understand the development of internal heat and mass transfers inside the boards and the evolution of drying stresses during oscillating conditions. A simple analytical model adapted to the oscillating conditions was proposed, particularly for kiln users who don't have access to sophisticated numerical tools. The numerical approach used the simulation tool TransPore, able to simulate oscillating drying in more realistic conditions. Its mechanical module was used to set accurate drying schedules to study the effect of oscillating conditions on stresses relaxation. - Finally, a second experimental part was performed in a laboratory scale kiln, at the board scale, to test the information obtained theoretically. A non-symmetrical drying device (flying wood) and two different loaded drying devices (cantilever beam test and three points bending) were used to study the effect of oscillations. However, it is difficult to see the oscillating conditions effect on the stresses relaxation. The confrontation between experimental results at the board scale and the numerical simulation showed the significant effect produced on experimental results by parasite oscillations of small periods and intensities, originated by the kiln regulation. Further work should consider some modifications of the time dependent mechanical behavior model in order to capture the experimentally observed behavior
BENEDETTO, ALESSANDRO. "The temporal dynamics of vision for action and perception." Doctoral thesis, 2017. http://hdl.handle.net/2158/1079075.
Full text方柏元. "Digital-micro-fluid manipulation and oscillation behavior." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/75891862949732362574.
Full textHuang, Jyun Ming, and 黃俊銘. "Nonlinear Oscillation Behavior of a Gyrotron Traveling-Wave Amplifier." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/88296657578054426017.
Full textDevarakonda, Nagini. "Nonlinear Behavior of Longitudinal Waves in the Oscillations of Rijke Tube." 2007. http://trace.tennessee.edu/utk_gradthes/278.
Full textYang, Rong-Huei, and 楊榮輝. "Dynamic Behavior Study In Laser Syster From Chaos To Quasiperiodic Relaxation Oscillations." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/40100819131938472505.
Full text國立交通大學
理學院碩士在職專班應用科技學程
98
The purpose of this study is by experiments and observations to discover the output signal, it is produced by the plane-parallel resonator. The output time domain signal is continuous wave (CW) observed under the general oscilloscope (resolution 500MHz). The CW signal is parallel with X-axis (time axis). But when we observed the signal under the high speed oscilloscope (resolution 40GHz), there were still dynamic phenomena in the optical resonator. By means of changed the different factors, for examples, changed wedge-cut laser crystal and wedge-cut output coupler, we can clearly observe dynamic variations and fluctuations in different situations. Therefore, to advance experiments and discover that using the closed coupled cavity is to form the optical resonator. It may obtain not only a uniform periodic self pulsations signal but also a near perfect mode-locking output pattern. Besides the cavity can also offer a compact size resonator, easily modulate the length of the optical cavity, and obtain different repeating frequency。 Due to the higher laser output repeating frequencies、 sinusoidal-like pattern、 shortened the cavity and simple resonator structure characteristics, it can extremely get promising applications in industrial fields, such as applications in telecommunication systems.
Moreland, Heather L. "Determination of the Filippov solutions of the nonlinear oscillator with dry friction." Thesis, 2001. http://hdl.handle.net/1957/32440.
Full textGraduation date: 2002
Gottlieb, Oded. "Nonlinear oscillations, bifurcations and chaos in ocean mooring systems." Thesis, 1991. http://hdl.handle.net/1957/36341.
Full textGraduation date: 1992
Chen-HsuanFang and 方晨亘. "Studies on oscillation behavior of EIT-based light storage and retrieval." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/21176498166677129618.
Full text國立成功大學
物理學系碩博士班
101
We experimentally study on the oscillation behavior of light storage and retrieval due to the interference effect of multiple electromagnetically-induced-transparency systems in Zeeman degenerate states. The experiment is performed in cold Rubidium atoms with an optical density of about 20. We measure the oscillation frequency of the retrieved light as a function of the strength of the external magnetic field. Comparison between the experimental data and theoretical predictions shows good agreement. Moreover, we can reduce the residual magnetic field to below 1 mG with this method.
King, Paul E. "Deterministic and stochastic control of nonlinear oscillations in ocean structural systems." Thesis, 2006. http://hdl.handle.net/1957/29586.
Full textGraduation date: 2006
ZHAO, YOU-GUANG, and 趙有光. "Oscillation and asymptotic behavior of solutions of a second order nonlinear difference equation." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/30355723074142505151.
Full textChang, Haw-Yuan, and 張浩元. "Nonlinear PI/ PID control straegies of bioreactor systems with self-oscillating behavior." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/33874777368548037248.
Full text國立雲林科技大學
工業化學與災害防治研究所
92
This article into three partly, to confer nonlinear PI/PID straegies recently to expand of bioreactor systems with self-oscillating behavior. Control law have a percentage, in-tegral and differential parameters in common with classic PID controller the base is second order differential equationis, both is convenient to make use of industry.The classic PID controller already had many methods to find the percentage、integral and differential parameters for optimum operation.This paper use a optimal control design to find the percentage, integral and differential parameters of nonlinear PID controller. The performance and robustness characteristics of developed control methodologies are evaluated through simulations.
KIVINDU, REUBEN MWANZA, and REUBEN MWANZA KIVINDU. "Flame Behavior and Thermal Structure of Combusting Non-premixed Plane Jets with and without Self-excited Transverse Oscillations." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/yn4gb2.
Full text國立臺灣科技大學
機械工程系
106
The flame behavior and thermal structure of combusting non-premixed plane jets with and without self-excited transverse oscillations were investigated experimentally. The transversely-oscillating plane jet was generated by a specially designed fluidic oscillator. The flame behavior was studied using the instantaneous- and long-exposure photography techniques. Temperature and combustion-product concentration distributions were measured using a fine-wire type-R thermocouple and a gas analyzer, respectively. The results showed that the combusting transversely-oscillating plane jets had distributed blue flames with plaited-like edges, while the corresponding combusting non-excited plane jet had laminar blue-edged flames in the near field. The transversely-oscillating plane jet flames were categorized into three characteristic flame modes: attached flame, transitional flame, and lifted flame. The non-excited plane jet flames showed three flame modes, viz; momentum-deficit flame, transitional flame, and momentum-dominated flame. At high Reynolds number (Rej > 1204), the transversely-oscillating jet flames were significantly shorter and wider with shorter reaction-dominated zones than those of the non-oscillating plane jet flames. In addition, the transversely-oscillating combusting jets presented larger carbon dioxide and smaller unburned hydrocarbon concentrations, as well as portrayed characteristics of partially premixed flames. The non-oscillating combusting jets presented characteristics of diffusion flames. Generally, the transversely-oscillating jet flame had combustion performance characteristics that were superior to its non-oscillating plane jet flame counterpart. The improved combustion performance of the transversely-oscillating jet was due to the enhanced entrainment, mixing, and lateral spreading of the jet flow, which were induced by the vortical flow structure generated by lateral periodic jet oscillations, as well as the high turbulence created by the breakup of the vortices. The effects of co-flowing air streams and aspect ratios on the flame behavior and thermal structure of gaseous fuel jets issued from rectangular nozzles were additionally investigated and discussed.
LIU, SHIH-PEI, and 劉師沛. "Numeric investigation of the 3-D nonlinear resonant behaviors of gas oscillation of in a closed tube." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/j44s8y.
Full text國立臺灣科技大學
機械工程系
99
Traditionally, the study of standing wave resonance inside a closed tube is focussed on the low frequency resonance system (generally below 200 Hz), which is limited by the mechanical transmission mechanisms used. In order to reduce the space taken by the mechanical transmission mechanisms, high frequency resonance system is favored. In addition, it is very difficult to measure the variations of physical quantities inside the resonance tube with current technologies available. However, this presents no difficulties in using numerical simulation to monitor the variations of physical quantities inside the tube. In this work, the resonance behaviors inside a closed tube (0.0435 m in length, 0.026 m inside diameter) driven by a reciprocating piston at a frequency of 4000 Hz are studied. The tube is assumed to be axis-symmetric and the walls are assumed to be adiabatic. The effects of detuning and frequency multiplication on the nonlinear resonance are investigated. Closed to the exact resonance, the pressure waveforms are significantly distorted and become asymmetric. Formation of shock waves can be clearly observed. Due to the steep velocity gradient inside the velocity boundary layer, significant shear stresses occurs near the velocity boundary layer and kinetic energy is dissipated and converted into heat. This heat will accumulate inside the velocity boundary layer due to the adiabatic boundary conditions. This, in turn, will lead to the growth of thermal boundary layer and result in a very thick thermal boundary layer. The results of the simulations can provide the necessary guidelines for the selection of the proper locations of the stack plates inside a thermoacoustic resonance tube.
Cheng-HanWu and 吳承翰. "Experimental Studies of Two Phase Flow Behaviors and Heat Transfer within Surface Modified Oscillating Heat Pipes." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/46780062686056620431.
Full text"The Effects of Nonlinear Damping on Post-flutter Behavior Using Geometrically Nonlinear Reduced Order Modeling." Master's thesis, 2015. http://hdl.handle.net/2286/R.I.29759.
Full textDissertation/Thesis
Masters Thesis Mechanical Engineering 2015
Cheung, Shilin. "Interfacial Behavior of Immortalized Murine Hypothalamic Neurons Studied by an Acoustic Transverse Wave Biosensor." Thesis, 2012. http://hdl.handle.net/1807/32683.
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