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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.
41

Evaluation de la sensibilité de l’instrument FCI à bord du nouveau satellite Meteosat Troisième Génération imageur (MTG-I) aux variations de la quantité d’aérosols d’origine désertique dans l’atmosphère / Assessment of the sensitivity of the instrument FCI aboard the new satellite Meteosat Third Generation imager (MTG -I) to changes in load of dust aerosols in the atmosphere

Aoun, Youva 19 September 2016 (has links)
Cette thèse porte sur une méthodologie d’estimation des capacités d’un futur instrument spatioporté. Le cas d’étude est l’instrument Flexible Combined Imager (FCI) à bord du futur satellite Meteosat Troisième Génération Imageur (MTG-I), et plus particulièrement ses capacités à détecter des variations de quantité d’aérosols désertiques dans l’atmosphère. Une meilleure connaissance de ces aérosols fait partie des besoins régulièrement exprimés pour l’étude du climat, la prévision météorologique ou l’estimation de la ressource solaire dans des zones arides comme le Sahara. Ce type d’aérosols est abondant dans l’atmosphère. Leurs propriétés physico-chimique les rendent distinguables des autre types d’aérosols comme ceux résultant de la pollution d’origine anthropique, d’autant qu’ils sont émis dans des zones protégées des contaminations par ces autres types. Ils représentent donc un cas d’étude simple pour valider la méthodologie développée dans cette thèse.La méthodologie consiste à réaliser un simulateur de vue du sol par l’instrument, à effectuer de très nombreuses simulations des luminances mesurées par l’instrument sous diverses conditions atmosphériques et de l’albédo du sol, à analyser les résultats de manière à quantifier l’influence de chaque variable dans la variation de la luminance, puis à conclure quant aux capacités de détection grâce un critère de détectabilité prenant en compte les caractéristiques de l’instrument.Le simulateur développé a été validé par confrontation avec des mesures réelles de l’instrument SEVIRI à bord du satellite Meteosat Second Generation. L’innovation principale réside dans l’usage de l’approche d’analyse de sensibilité globale (GSA). Cette dernière quantifie l’influence de chaque variable séparément ainsi que les termes croisés. Elle exploite des fonctions de répartition statistique des variables extraites d’observations, et permet par conséquent d’obtenir une analyse de sensibilité réaliste. La GSA produit aussi des fonctionnelles modélisant l’influence d’une ou plusieurs variables sur la variabilité du signal observé et utilisables pour différentes applications dans la télédétection. / This thesis deals with a methodology to assess the capabilities of future spaceborne instruments. The case study is the Flexible Combined Imager (FCI) of the future Meteosat Third Generation Imaging mission (MTG - I), and in particular its ability to detect variations in load of desert aerosols in a realistically variable atmosphere. A better understanding of the behavior of these aerosols is part of regularly expressed needs for the study of the climate, weather forecast or assessment of the solar resource in arid areas such as the Sahara. This type of aerosols is abundant in the atmosphere. Their physical and chemical properties make them distinguishable from other types of aerosols such as those resulting from anthropogenic pollution, especially as they are emitted in areas protected from contamination by these other types. They therefore represent a simple case study to validate the methodology developed in this thesis.The methodology is to provide a simulator of the view of the instrument to perform a large number of simulations of the radiance measured under different atmospheric conditions and ground albedo, to analyze the results in order to quantify the influence of each variable in the variation of radiance, and then conclude on the capabilities of detection through a test of detectability taking into account the characteristics of the instrument.The developed simulator was validated by comparison against actual measurements of the SEVIRI instruments onboard Meteosat Second Generation satellites. The main innovation lies in the use of the global sensitivity analysis approach (GSA). The latter quantifies the influence of each variable separately as well as their crossed terms. Cumulative distribution functions were computed from actual observations and allow a realistic sensitivity analysis of the instrument. The GSA is also used to compute functional representation of the influence of one or more variables on the variability of the observed signal. The usefulness of such representations is discussed for various applications in remote sensing.
42

HST HOT-JUPITER TRANSMISSION SPECTRAL SURVEY: CLEAR SKIES FOR COOL SATURN WASP-39b

Fischer, Patrick D., Knutson, Heather A., Sing, David K., Henry, Gregory W., Williamson, Michael W., Fortney, Jonathan J., Burrows, Adam S., Kataria, Tiffany, Nikolov, Nikolay, Showman, Adam P., Ballester, Gilda E., Desert, Jean-Michel, Aigrain, Suzanne, Deming, Drake, des Etangs, Alain Lecavelier, Vidal-Madjar, Alfred 10 August 2016 (has links)
We present the. Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) optical transmission spectroscopy of the cool Saturn-mass exoplanet WASP-39b from 0.29-1.025 mu m, along with complementary transit observations from Spitzer IRAC at 3.6 and 4.5 mu m. The low density and large atmospheric pressure scale height of WASP-39b make it particularly amenable to atmospheric characterization using this technique. We detect a Rayleigh scattering slope as well as sodium and potassium absorption features; this is the first exoplanet in which both alkali features are clearly detected with the extended wings predicted by cloud-free atmosphere models. The full transmission spectrum is well matched by a clear H-2-dominated atmosphere, or one containing a weak contribution from haze, in good agreement with the preliminary reduction of these data presented in Sing et al.. WASP-39b is predicted to have a pressure-temperature profile comparable to that of HD 189733b and WASP-6b, making it one of the coolest transiting gas giants observed in our HST STIS survey. Despite this similarity, WASP-39b appears to be largely cloud-free, while the transmission spectra of HD 189733b and WASP-6b both indicate the presence of high altitude clouds or hazes. These observations further emphasize the surprising diversity of cloudy and cloud-free gas giant planets in short-period orbits and the corresponding challenges associated with developing predictive cloud models for these atmospheres.
43

Genome wide epigenetic analyses of Araptus attenuatus, a bark beetle

Seshadri, Chitra 01 January 2016 (has links)
Phylogeographic studies have relied on surveying neutral genetic variation in natural populations as a way of gaining better insights into the evolutionary processes shaping present day population demography. Recent emphasis on understanding putative adaptive variation have brought to light the role of epigenetic variation in influencing phenotypes and the mechanisms underlying local adaptation. While much is known about how methylation acts at specific loci to influence known phenotypes, there is little information on the spatial genetic structure of genome-wide patterns of methylation and the extent to which it can extend our understanding of both neutral and putatively adaptive processes. This research examines spatial genetic structure using paired nucleotide and methylation genetic markers in the Sonoran bark beetle, Araptus attenuatus, for which we have a considerable knowledge about its neutral demographic history, demography, and factors influencing ongoing genetic connectivity. Using the msAFLP approach, we attained 703 genetic markers. Of those, 297 were polymorphic in both nucleotide (SEQ) and methylation (METH) were assayed from 20 populations collected throughout the species range. Of the paired SEQ and METH locis, the METH were both more frequent (16% vs. 7%), maintained more diversity (Shannon IMeth = 0.361 vs. ISeq=0.272), and had more among-population genetic structure (ΦST; Meth = 0.035 vs. ΦST; Seq= 0.008) than their paired SEQ loci. Interpopulation genetic distance in both SEQ and METH markers were highly correlated, with 16% of the METH loci having sufficient signal to reconstruct phylogeographic history. Allele frequency variation at five loci (two SEQ and three METH) showed significant relationships with at-site bioclimatic variables suggesting the need for subsequent analysis addressing non-neutral evolution. These results suggest that methylation can be as informative as nucleotide variation when examining spatial genetic structure for phylogeography, connectivity, and, identifying putatively adaptive genetic variance.
44

Using remote sensing to explore the role of ambient temperature in determining gemsbok (Oryx gazella) usage of a heterogeneous landscape in the central Kalahari

Tromp, Leon Rocher 20 January 2016 (has links)
A research report submitted to the Faculty of Science, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Master of Science Johannesburg, August 2015 / The central Kalahari is likely to become hotter and drier as a result of climate change in the region. These changes may result in behavioural changes in Gemsbok due to temperature induced stress, in spite of physiological and behavioural adaptations, and are likely to manifest in a preference for particular landscape patch classes. Recent Landsat 8 satellite imagery and classification analysis were used to map landscape patch classes in a heterogeneous landscape in the central Kalahari. The classification map of the research area identified 6 classes of landscape patches used by Gemsbok. Eight collared Gemsbok were tracked by satellite to monitor their movement in their respective home ranges over a period of 9 months. Gemsbok locations were plotted on to the classification map, and location frequency distributions were produced for each landscape patch class. Gemsbok home ranges were calculated using minimum convex polygon geometry, and the available patch class areas within each home range were analysed against the usage patterns of each animal. The analysis showed less preference for shade producing classes and more preference for open classes. Exploration of the role of temperature in landscape patch selection showed that temperature is a weak predictor of patch class, that critical temperature thresholds have not yet been reached, and that Gemsbok preference for pans is more likely related to seasonally available forage and reduced predation risk in a “landscape of fear” (Laundré, Hernández, & Altendorf, 2001).
45

Deep Percolation in Arid Piedmont Watersheds and Its Sensitivity to Ecosystem Change

January 2017 (has links)
abstract: Population growth within drylands is occurring faster than growth in any other ecologic zone, putting pressure on already stressed water resources. Because the availability of surface water supplies in drylands tends to be highly variable, many of these populations rely on groundwater. A critical process contributing to groundwater recharge is the interaction between ephemeral channels and groundwater aquifers. Generally, it has been found that ephemeral channels contribute to groundwater recharge when streamflow infiltrates into the sandy bottoms of channels. This process has traditionally been studied in channels that drain large areas (10s to 100s km2). In this dissertation, I study the interactions between surface water and groundwater via ephemeral channels in a first-order watershed located on an arid piedmont slope within the Jornada Experimental Range (JER) in the Chihuahuan Desert. To achieve this, I utilize a combination of high-resolution observations and computer simulations using a modified hydrologic model to quantify groundwater recharge and shed light on the geomorphic and ecologic processes that affect the rate of recharge. Observational results indicate that runoff generated within the piedmont slope contributes significantly to deep percolation. During the short-term (6 yr) study period, we estimated 385 mm of total percolation, 62 mm/year, or a ratio of percolation to rainfall of 0.25. Based on the instrument network, we identified that percolation occurs inside channel areas when these receive overland sheetflow from hillslopes. By utilizing a modified version of the hydrologic model, TIN-based Real-time Integrated Basin Simulator (tRIBS), that was calibrated and validated using the observational dataset, I quantified the effects of changing watershed properties on groundwater recharge. Distributed model simulations quantify how deep percolation is produced during the streamflow generation process, and indicate that it plays a significant role in moderating the production of streamflow. Sensitivity analyses reveal that hillslope properties control the amount of rainfall necessary to initiate percolation while channel properties control the partitioning of hillslope runoff into streamflow and deep percolation. Synthetic vegetation experiments show that woody plant encroachment leads to increases in both deep percolation and streamflow. Further woody plant encroachment may result in the unexpected enhancement of dryland aquifer sustainability. / Dissertation/Thesis / Doctoral Dissertation Geological Sciences 2017
46

Neuronal basis of temporal polyethism and sky-compass based navigation in \(Cataglyphis\) desert ants / Die neuronale Grundlage von Alterspolyethismus und Himmelskompassnavigation in der Wüstenameise \(Cataglyphis\)

Schmitt, Franziska January 2017 (has links) (PDF)
Desert ants of the genus Cataglyphis (Formicinae) are widely distributed in arid areas of the palearctic ecozone. Their habitats range from relatively cluttered environments in the Mediterranean area to almost landmark free deserts. Due to their sophisticated navigational toolkit, mainly based on the sky-compass, they were studied extensively for the last 4 decades and are an exceptional model organism for navigation. Cataglyphis ants exhibit a temporal polyethism: interior workers stay inside the dark nest and serve as repletes for the first ∼2 weeks of their adult life (interior I). They then switch to nursing and nest maintenance (interior II) until they transition to become day-active outdoor foragers after ∼4 weeks. The latter switch in tasks involves a transition phase of ∼2-3 days during which the ants perform learning and orientation walks. Only after this last phase do the ants start to scavenge for food as foragers. In this present thesis I address two main questions using Cataglyphis desert ants as a model organism: 1. What are the underlying mechanisms of temporal polyethism? 2. What is the neuronal basis of sky-compass based navigation in Cataglyphis ants? Neuropeptides are important regulators of insect physiology and behavior and as such are promising candidates regarding the regulation of temporal polyethism in Cataglyphis ants. Neuropeptides are processed from large precursor proteins and undergo substantial post-translational modifications. Therefore, it is crucial to biochemically identify annotated peptides. As hardly any peptide data are available for ants and no relevant genomic data has been recorded for Cataglyphis, I started out to identify the neuropeptidome of adult Camponotus floridanus (Formicinae) workers (manuscript 1). This resulted in the first neuropeptidome described in an ant species – 39 neuropeptides out of 18 peptide families. Employing a targeted approach, I identified allatostatin A (AstA), allatotropin (AT), short neuropeptide F (sNPF) and tachykinin (TK) using mass spectrometry and immunohistology to investigate the distribution of AstA, AT and TK in the brain (manuscript 2). All three peptides are localized in the central complex, a brain center for sensory integration and high-order control of locomotion behavior. In addition, AstA and TK were also found in visual and olfactory input regions and in the mushroom bodies, the centers for learning and memory formation. Comparing the TK immunostaining in the brain of 1, 7 and 14 days old dark kept animals revealed that the distribution in the central complex changes, most prominently in the 14 day old group. In the Drosophila central complex TK modulates locomotor activity levels. I therefore hypothesize that TK is involved in the internal regulation of the interior I–interior II transition which occurs after ∼2 weeks of age. I designed a behavioral setup to test the effect of neuropeptides on the two traits: ’locomotor activity level’ and ’phototaxis’ (manuscript 3). The test showed that interior I ants are less active than interior II ants, which again are less active than foragers. Furthermore, interior ants are negatively phototactic compared to a higher frequency of positive phototaxis in foragers. Testing the influence of AstA and AT on the ants’ behavior revealed a stage-specific effect: while interior I behavior is not obviously influenced, foragers become positively phototactic and more active after AT injection and less active after AstA injection. I further tested the effect of light exposure on the two behavioral traits of interior workers and show that it rises locomotor activity and results in decreased negative phototaxis in interior ants. However, both interior stages are still more negatively phototactic than foragers and only the activity level of interior II ants is raised to the forager level. These results support the hypothesis that neuropeptides and light influence behavior in a stage-specific manner. The second objective of this thesis was to investigate the neuronal basis of skycompass navigation in Cataglyphis (manuscript 4). Anatomical localization of the sky-compass pathway revealed that its general organization is highly similar to other insect species. I further focused on giant synapses in the lateral complex, the last relay station before sky-compass information enters the central complex. A comparison of their numbers between newly eclosed ants and foragers discloses a rise in synapse numbers from indoor worker to forager, suggesting task-related synaptic plasticity in the sky-compass pathway. Subsequently I compared synapse numbers in light preexposed ants and in dark-kept, aged ants. This experiment showed that light as opposed to age is necessary and sufficient to trigger this rise in synapse number. The number of newly formed synapses further depends on the spectral properties of the light to which the ants were exposed to. Taken together, I described neuropeptides in C. floridanus and C. fortis, and provided first evidence that they influence temporal polyethism in Cataglyphis ants. I further showed that the extent to which neuropeptides and light can influence behavior depends on the animals’ state, suggesting that the system is only responsive under certain circumstances. These results provided first insight into the neuronal regulation of temporal polyethism in Cataglyphis. Furthermore, I characterized the neuronal substrate for sky-compass navigation for the first time in Cataglyphis. The high level of structural synaptic plasticity in this pathway linked to the interior–forager transition might be particularly relevant for the initial calibration of the ants’ compass system. / Wüstenameisen der Gattung Cataglyphis sind weit verbreitet in ariden Gebieten der paläarktischen Ökozone. Die von ihnen bewohnten Habitate reichen von landmarkenreichen Arealen im Mittelmeerraum, zu beinahe landmarkenfreien Wüstengebieten. Aufgrund ihres hochentwickelten Navigationssystems, welches größtenteils auf dem Himmelskompass basiert, wurden sie in den letzten 4 Jahrzehnten extensiv studiert und sind ein einzigartiges Modellsystem für Navigation. Cataglyphis weisen einen alterskorrelierten Polyethismus auf: Innendienstler dienen als Speichertiere für die ersten ∼2 Wochen ihres adulten Lebens (Interior I). Sie gehen daraufhin zu Brutpflege und Nestbau (Interior II) über bis sie nach ∼4 Wochen zu tagaktiver Furagiertätitkeit außerhalb ihres Nestes wechseln. Dieser letzte Übergang dauert ∼2-3 Tage und wird von den Ameisen genutzt, um Lernund Orientierungsläufe durchzuführen. In der vorliegenden Arbeit befasse ich mich vor allem mit zwei Fragen, die ich mit Hilfe von Cataglyphis als Modellorganismus beantworten möchte: 1. Welches sind die zugrunde liegenden Mechanismen des Alterspolyethismus? 2. Was ist die neuronale Grundlage von Navigation, die auf dem Himmelskompass basiert? Neuropeptide sind bedeutende Regulatoren der Physiologie und des Verhaltens von Insekten und als solche vielversprechende Kandidaten im Hinblick auf die Regulation des Alterspolyethismus in Cataglyphis Ameisen. Neuropeptide werden aus größeren Vorläuferproteinen herausgeschnitten und posttranslational stark modifiziert. Daher ist es wichtig, annotierte Peptide auch biochemisch zu identifizieren. Da für Ameisen kaum Peptiddaten zur Verfügung stehen und es zudem keine relevanten genomischen Daten für Cataglyphis gibt, identifizierte ich zunächst das Neuropeptidom adulter Camponotus floridanus (Formicinae) Arbeiterinnen (Manuskript 1). Daraus resultierte das erste Neuropeptidom, das für eine Ameisenart beschrieben wird—39 Neuropeptide aus 18 Peptidfamilien. In einer weiteren Studie identifizierte ich gezielt die Neuropeptidfamilien Allatostatin A (AstA), Allatotropin (AT), das kurze Neuropeptid F (sNPF) und Tachykinin (TK) mittels Massenspektroskopie und untersuchte die Verteilung von AstA, AT und TK im Gehirn mit Hilfe der Immunhistologie (Manuskript 2). Alle drei Peptide sind im Zentralkomplex lokalisiert, dem Gehirnzentrum welches sensorische Eingänge integriert und in einer übergeordneten Rolle Lokomotorverhalten steuert. AstA und TK sind zudem in den visuellen und olfaktorischen Eingangsregionen, sowie den Pilzkörpern, den Zentren für Lernen und Gedächtnisbildung, zu finden. Ein Vergleich der TK-Immunfärbung im Gehirn von 1, 7 und 14 Tage alten im Dunkeln gehaltenen Tieren zeigt, dass sich die Verteilung im Zentralkomplex verändert— dies ist besonders prominent in der 14 Tage alten Gruppe. In Drosophila moduliert TK im Zentralkomplex Lokomotoraktivität. Basierend darauf stelle ich die Hypothese auf, dass TK in der internen Regulierung des Übergangs von Interior I zu Interior II involviert ist, welchen die Tiere im Alter von ∼2 Wochen durchlaufen. Für eine dritte Studie konstruierte ich ein Verhaltenssetup um den Einfluss von Neuropeptiden und Licht auf die beiden Verhaltensmerkmale ’Lokomotoraktivität’ und ’Phototaxis’ zu testen (Manuskript 3). Der Test zeigte, dass Interior I Ameisen weniger aktiv sind als Interior II Ameisen, welche wiederum weniger aktiv sind als Furageure. Zudem sind Interior Ameisen negativ phototaktisch, verglichen mit einer häufiger zu beobachtenden positiven Phototaxis bei Furageuren. Im Test zeigte sich auch, dass der Einfluss von AstA und AT stadiumsspezifisch ist: während das Verhalten von Interior I Tieren nicht offensichtlich beeinflusst wird, werden Furageure durch die Injektion von AT positiv phototaktisch, sowie aktiver und AstA-Injektion führt zu geminderter Lokomotoraktivität. Darüber hinaus testete ich den Lichteinfluss auf beide Verhaltensmerkmale in den Innendienststadien und zeige, dass er Lokomotoraktivität steigert und in einer geminderten negativen Phototaxis resultiert. Beide Innendienststadien sind jedoch weiterhin negativer phototaktisch als Furageure und nur die Lokomotoraktivtät von Interior II Ameisen wird auf das Niveau von Furageuren angehoben. Diese Ergebnisse stützen die Hypothese, dass Neuropeptide und Licht stadiumsspezifisch Verhalten beeinflussen. Der zweite Aspekt dieser Thesis war es, die neuronale Grundlage der Himmelskompassnavigation in Cataglyphis aufzuklären (Manuskript 4). Die neuroanatomische Lokalisation der Himmelskompasssehbahn zeigt, dass die allgemeine Organisation dieser neuronalen Bahn der bei bisher untersuchten anderen Insekten stark ähnelt. Ich habe mich daraufhin auf Riesensynapsen im lateralen Komplex konzentriert, der letzten Verschaltungsstation ehe die Himmelskompassinformation in den Zentralkomplex übertragen wird. Ein Vergleich zwischen der Synapsenzahl in frisch geschlüpfte Ameisen und erfahrenen Furageueren zeigte einen Anstieg der Synapsenzahl von Innendienst zu Furaguer, was aufgabenabhängige synaptische Plastizität in der Himmelskompasssehbahn suggeriert. In einem weiteren Versuch verglich ich die Riesensynapsenzahlen lichtexponierter Tiere und dunkel gehaltener, gealteter Tiere. Dieses Experiment zeigte, dass der Zuwachs an Riesensynapsen durch den Lichteinfluss ausgelöst wird und keinen altersabhängigen Prozess darstellt. Zudem verändert sich die Anzahl der neu gebildeten Riesensynapsen in Abhängigkeit von den spektralen Eigenschaften des Lichts, dem die Ameisen ausgesetzt sind. Zusammengefasst beschrieb ich in dieser Thesis Neuropeptide in C. floridanus und Cataglyphis und lieferte erste Evidenz, dass diese den Alterspolyethismus in Cataglyphis beeinflussen. Zudem zeigte ich, dass das Ausmaß in dem Neuropeptide und Lichtexposition Verhalten beeinflussen können, stadiumsspezifisch ist. Dies suggeriert, dass das System nur unter bestimmten Bedingungen auf externe Einflüsse reagiert. Diese Ergebnisse lieferten erste wichtige Einblicke in die neuronale Grundlage von Alterspolyethismus in Cataglyphis. Zudem charakterisierte ich erstmals das neuronale Substrat der Himmelskompassnavigation in Cataglyphis. Das hohe Maß an synaptischer Plastizität in dieser Sehbahn beim Übergang von Innenzu Außendienst, könnte besondere Relevanz für die initiale Kalibrierung des Kompasssystems haben.
47

Na okraji vojenské společnosti. Vojenští invalidé, zběhové a delikventi v císařsko-královské armádě za sedmileté války / On the Edge of the Military Society. Military Invalids, Deserters and Delinquents in the Imperial-Royal Army in the Seven Years' War

Švehelka, Ondřej January 2017 (has links)
This thesis concerns military invalids, deserters and delinquents in the Imperial-Royal Army during the Seven Years' War (1756-1763). Its essence lies in the research of documents originated from the activity of the Representations and Chambers, the supreme representative offices in Bohemia and Moravia. The elementary methodological approach comes from a positivist conception, therefore it interprets the information found within the sources as a story (in a certain sense of word) based on the reality which is recorded by them. The theoretical part is enhanced by the outcomes of study of auxiliary books called Elenchs that provide information even about such sources that have not been preserved till today. Thus, I try to answer the question to which extent it is still possible to use them. The main component of the work is formed by three chapters which are dedicated to particular categories of the military persons in an order stated above. Within them, I present the results of the source research that, in the case of the invalids, concern notably their economic security and utilization for the Habsburg Monarchy's war effort. The chapter about the military deserters continues my previous research and amends it (among else) with newly found facts within the sphere of the enlightened-absolutist...
48

Analysis of neurophysiological signals from the proprioceptor system of insects / Análise de sinais eletrofisiológicos do sistema proprioceptor de insetos

Lima, Daniel Rodrigues de 17 November 2016 (has links)
Proprioception is the ability to sense body position necessary for coordinate precise movements. Despite the low complexity of insect neuronal systems, scientists are studying their motor control system. Researchers performed experiments in desert locusts by stimulating their apodeme and recording the neuronal response. Previous studies reported variations in neuronal spiking rates related to acceleration, velocity and position sensitivity. Their results led us to the assumption that either there are different kinds of sensory neurons, or there is only one type of neuron responding to various Physical quantities. Therefore, this research intends to investigate the different spiking rates. We also want to study the influence of apodemes excitations in sensory neurons with information theoretical measures. However, the way signals were recorded does not allow the calculation of delayed transfer entropy (DTE) between sensory neurons. To solve that problem we propose a method to estimate parameters of connections in such scenarios. Our analysis will model the time spent between spikes with survival functions. The influence of excitation in the neuronal response will be analyzed with DTE, which will also be used to validate the methods of simulation. Results show that there is evidence to support the assumption of different spiking rates among sensory neurons. DTE suggests the existence of intermediate processing nodes between excitation and some sensory neurons. A further simulation joining the methods proposed and neuronal signals showed that models considering intermediate pathways present a good fit to the data. We suggest that the different responses of sensory neurons are not due to various types of neurons, but to a preprocessing layer. / Propriocepção é a capacidade de monitorar a posição do corpo necessária para coordenar movimentos precisos. Apesar da baixa complexidade dos sistemas neuronais de insetos, cientistas têm estudado seu controle motor. Pesquisadores realizaram experimentos em gafanhotos estimulando mecanicamente seu apódema e registrando a resposta neuronal. Estudos anteriores relatam variações nas taxas de spiking, e as relacionam com sensibilidades à aceleração, à velocidade e à posição. Seus resultados nos levaram às suposições de que ou existem diferentes tipos de neurônios sensores ou há apenas um tipo de neurônio sensível à diferentes grandezas físicas. Portanto, esta pesquisa pretende investigar as diferentes taxas de spiking e estudar a influência das excitações do apódema em neurônios sensores com medidas de teoria da informação. No entanto, a forma como os sinais foram gravados não permite calcular-se a transferência de entropia atrasada (DTE) entre neurônios sensores. Para tanto, propôs-se um método de estimação de parâmetros para ligações em tais cenários. As análises modelarão o tempo gasto entre spikings com funções de sobrevida. Além disso, a influência da excitação sobre a resposta neuronal será analisada com DTE, a qual também será utilizada para validar os métodos de simulação. Os resultados mostram que há evidências para suportar a hipótese de diferentes taxas de spiking. A DTE sugere a existência de nós intermediários (entre excitação e alguns neurônios sensoriais). Posteriormente, uma simulação juntando os métodos propostos e os sinais neuronais mostrou que modelos considerando caminhos intermediários se ajustam bem aos dados. Por fim, os resultados sugerem que as diferentes respostas de neurônios sensores não acontecem devido a diferentes tipos de neurônios, mas sim à uma camada de pré-processamento.
49

Analysis of neurophysiological signals from the proprioceptor system of insects / Análise de sinais eletrofisiológicos do sistema proprioceptor de insetos

Daniel Rodrigues de Lima 17 November 2016 (has links)
Proprioception is the ability to sense body position necessary for coordinate precise movements. Despite the low complexity of insect neuronal systems, scientists are studying their motor control system. Researchers performed experiments in desert locusts by stimulating their apodeme and recording the neuronal response. Previous studies reported variations in neuronal spiking rates related to acceleration, velocity and position sensitivity. Their results led us to the assumption that either there are different kinds of sensory neurons, or there is only one type of neuron responding to various Physical quantities. Therefore, this research intends to investigate the different spiking rates. We also want to study the influence of apodemes excitations in sensory neurons with information theoretical measures. However, the way signals were recorded does not allow the calculation of delayed transfer entropy (DTE) between sensory neurons. To solve that problem we propose a method to estimate parameters of connections in such scenarios. Our analysis will model the time spent between spikes with survival functions. The influence of excitation in the neuronal response will be analyzed with DTE, which will also be used to validate the methods of simulation. Results show that there is evidence to support the assumption of different spiking rates among sensory neurons. DTE suggests the existence of intermediate processing nodes between excitation and some sensory neurons. A further simulation joining the methods proposed and neuronal signals showed that models considering intermediate pathways present a good fit to the data. We suggest that the different responses of sensory neurons are not due to various types of neurons, but to a preprocessing layer. / Propriocepção é a capacidade de monitorar a posição do corpo necessária para coordenar movimentos precisos. Apesar da baixa complexidade dos sistemas neuronais de insetos, cientistas têm estudado seu controle motor. Pesquisadores realizaram experimentos em gafanhotos estimulando mecanicamente seu apódema e registrando a resposta neuronal. Estudos anteriores relatam variações nas taxas de spiking, e as relacionam com sensibilidades à aceleração, à velocidade e à posição. Seus resultados nos levaram às suposições de que ou existem diferentes tipos de neurônios sensores ou há apenas um tipo de neurônio sensível à diferentes grandezas físicas. Portanto, esta pesquisa pretende investigar as diferentes taxas de spiking e estudar a influência das excitações do apódema em neurônios sensores com medidas de teoria da informação. No entanto, a forma como os sinais foram gravados não permite calcular-se a transferência de entropia atrasada (DTE) entre neurônios sensores. Para tanto, propôs-se um método de estimação de parâmetros para ligações em tais cenários. As análises modelarão o tempo gasto entre spikings com funções de sobrevida. Além disso, a influência da excitação sobre a resposta neuronal será analisada com DTE, a qual também será utilizada para validar os métodos de simulação. Os resultados mostram que há evidências para suportar a hipótese de diferentes taxas de spiking. A DTE sugere a existência de nós intermediários (entre excitação e alguns neurônios sensoriais). Posteriormente, uma simulação juntando os métodos propostos e os sinais neuronais mostrou que modelos considerando caminhos intermediários se ajustam bem aos dados. Por fim, os resultados sugerem que as diferentes respostas de neurônios sensores não acontecem devido a diferentes tipos de neurônios, mas sim à uma camada de pré-processamento.
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The Pieces of Diasporic History in My Immigrant Family: Deserted Island Loneliness and Connections of Societies / 離散家庭的歷史碎片:荒島的孤單與社會的連結

Wu, Chia-Hung, 吳家弘 January 2017 (has links)
碩士 / 輔仁大學 / 心理學系 / 105 / I used to be a patient with mental illness. When I was in high school, I had suffered from emotional distress and thus chose to take the initiative in going to the psychiatric clinic for help. At that time, I also decided to aim at psychology department as top priority for college entrance and then carry out understanding of myself. I grew up in a family where my parents both came from other areas and had their own specific social contextual backgrounds different from Taiwan’s. My father is a veteran who was from Mainland China and follow KMT Government of Republic of China to come to Taiwan in 1949. My mother is a Chinese Indonesian who came to Taiwan to get married in the background of Chinese exclusion. As a second-generation immigrant, I have experienced various domestic quarrels in my family life which deeply influenced my own physical and mental state as well as career development. The study was written in self-narrative method, trying to review the problems and dilemmas that I encountered in different life stages in the experiences of education and immigrant / diasporic family, and to organize and reflect. In addition, in order to react to the situations of my family and expand my understanding of my parents' family of origin and myself, the study also records my various interventions and actions through different groups and fields, including searching for body and soul resources to support myself and my family, retrospecting to the histories of my parents and personally returning to Mainland China and Indonesia. Through these processes, I try to reframe the physical and mental states, relationship and personal development of mine and my family by broader societal / historical perspectives, and explore the possibilities of connections from the closed system of my family to the societies.

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