Comparison of the reliability of multifocal visual evoked cortical potentials generated by pattern reversal and pattern pulse stimulation

This study compared the effectiveness of the multifocal visual evoked cortical potentials (mfVEP) elicited by pattern pulse stimulation with that of pattern reversal in producing reliable responses (signal-to-noise ratio >1.359). Participants were 14 healthy subjects. Visual stimulation was obtained using a 60-sector dartboard display consisting of 6 concentric rings presented in either pulse or reversal mode. Each sector, consisting of 16 checks at 99% Michelson contrast and 80 cd/m² mean luminance, was controlled by a binary m-sequence in the time domain. The signal-to-noise ratio was generally larger in the pattern reversal than in the pattern pulse mode. The number of reliable responses was similar in the central sectors for the two stimulation modes. At the periphery, pattern reversal showed a larger number of reliable responses. Pattern pulse stimuli performed similarly to pattern reversal stimuli to generate reliable waveforms in R1 and R2. The advantage of using both protocols to study mfVEP responses is their complementarity: in some patients, reliable waveforms in specific sectors may be obtained with only one of the two methods. The joint analysis of pattern reversal and pattern pulse stimuli increased the rate of reliability for central sectors by 7.14% in R1, 5.35% in R2, 4.76% in R3, 3.57% in R4, 2.97% in R5, and 1.78% in R6. From R1 to R4 the reliability to generate mfVEPs was above 70% when using both protocols. Thus, for a very high reliability and thorough examination of visual performance, it is recommended to use both stimulation protocols.

Sleep pattern and learning in knockdown mice with reduced cholinergic neurotransmission

Impaired cholinergic neurotransmission can affect memory formation and influence sleep-wake cycles (SWC). In the present study, we describe the SWC in mice with a deficient vesicular acetylcholine transporter (VAChT) system, previously characterized as presenting reduced acetylcholine release and cognitive and behavioral dysfunctions. Continuous, chronic ECoG and EMG recordings were used to evaluate the SWC pattern during light and dark phases in VAChT knockdown heterozygous (VAChT-KDHET, n=7) and wild-type (WT, n=7) mice. SWC were evaluated for sleep efficiency, total amount and mean duration of slow-wave, intermediate and paradoxical sleep, as well as the number of awakenings from sleep. After recording SWC, contextual fear-conditioning tests were used as an acetylcholine-dependent learning paradigm. The results showed that sleep efficiency in VAChT-KDHET animals was similar to that of WT mice, but that the SWC was more fragmented. Fragmentation was characterized by an increase in the number of awakenings, mainly during intermediate sleep. VAChT-KDHET animals performed poorly in the contextual fear-conditioning paradigm (mean freezing time: 34.4±3.1 and 44.5±3.3 s for WT and VAChT-KDHET animals, respectively), which was followed by a 45% reduction in the number of paradoxical sleep episodes after the training session. Taken together, the results show that reduced cholinergic transmission led to sleep fragmentation and learning impairment. We discuss the results on the basis of cholinergic plasticity and its relevance to sleep homeostasis. We suggest that VAChT-KDHET mice could be a useful model to test cholinergic drugs used to treat sleep dysfunction in neurodegenerative disorders.

Chemical pattern of brazilian apples: a chemometric approach based on the Fuji and Gala varieties

The chemical composition of apple juices may be used to discriminate between the varieties for consumption and those for raw material. Fuji and Gala have a chemical pattern that can be used for this classification. Multivariate methods correlate independent continuous chemical descriptors with the categorical apple variety. Three main descriptors of apple juice were selected: malic acid, total reducing sugar and total phenolic compounds. A chemometric approach, employing PCA and SIMCA, was used to classify apple juice samples. PCA was performed with 24 juices from Fuji and Gala, and SIMCA, with 15 juices. The exploratory and predictive models recognized 88% and 64%, respectively, as belonging to a mixed domain. The apple juice from commercial fruits shows a pattern related to cv. Fuji and Gala with boundaries from 0.18 to 0.389 g.100 mL-1 (malic acid), from 8.65 to 15.18 g.100 mL-1 (total reducing sugar) and from 100 to 400 mg.L-1 (total phenolic compounds), but such boundaries were slightly shorter in the remaining set of commercial apple juices, specifically from 0.16 to 0.36 g.100 mL-1, from 9.25 to 15.5 g.100 mL-1 and from 180 to 606 mg.L-1 for acidity, reducing sugar and phenolic compounds, respectively, representing the acid, sweet and bitter tastes.

Ripening pattern of guava cv. Pedro Sato

Guava is a fruit with high respiration rates and a very short shelf life. Since information on its respiration pattern is contradictory, the objective was to study the changes occurring in the fruit during ripening and to relate them to the respiration behavior of this fruit. Guavas were picked at the half-ripe stage and stored for 8 days at 22 ± 1 ºC and 78 ± 1% relative humidity. The analyses conducted were: peel and pulp coloration, firmness, total soluble solids (TSS), total titratable acidity (TTA), and ethylene production. According to the results, it was verified that the parameters analyzed apparently do not coincide and are ethylene-independent. There was an accentuated ethylene production during ripening, starting from the 4th day. The ethylene synthesis continued increasing up to the 8th day, when the fruits were already decomposing. It was observed that the firmness decreased sharply in the first three days of ripening, and the skin and pulp color changed during ripening. The TSS, total soluble solids, and the TTA, total titratable acidity, practically did not change during the ripening, even with the increased ethylene production. It can be concluded that guava is a fruit that presents characteristics of climacteric and non-climacteric fruits.

Design and implementation of machine vision system for the mobile assembly robot

The review of intelligent machines shows that the demand for new ways of helping people in perception of the real world is becoming higher and higher every year. This thesis provides information about design and implementation of machine vision for mobile assembly robot. The work has been done as a part of LUT project in Laboratory of Intelligent Machines. The aim of this work is to create a working vision system. The qualitative and quantitative research were done to complete this task. In the first part, the author presents the theoretical background of such things as digital camera work principles, wireless transmission basics, creation of live stream, methods used for pattern recognition. Formulas, dependencies and previous research related to the topic are shown. In the second part, the equipment used for the project is described. There is information about the brands, models, capabilities and also requirements needed for implementation. Although, the author gives a description of LabVIEW software, its add-ons and OpenCV which are used in the project. Furthermore, one can find results in further section of considered thesis. They mainly represented by screenshots from cameras, working station and photos of the system. The key result of this thesis is vision system created for the needs of mobile assembly robot. Therefore, it is possible to see graphically what was done on examples. Future research in this field includes optimization of the pattern recognition algorithm. This will give less response time for recognizing objects. Presented by author system can be used also for further activities which include artificial intelligence usage.

Changes in the magnitude and pattern of translocation of photoassimilated ¹CO in soybean plants following an acute exposure to gamma radiation /

Young soybean plants (Glycine ~. L. cultivar Harosoy '63), grown under controlled conditions, were exposed to gamma radiation on a single occasion. One hour following exposure to 3,750 rads, the mature trifoliate leaf of the soybean plant was isolated in a closed system and permitted to photoassimilate approximately 1-5 pCi of 14C02 for 15 minutes. After an additional 45 minute-period, the plant was sacrificed and the magnitude of translocation and distribution pattern of 14C determined. In the non-irradiated plants 18~ of the total 14C recovered was outside the fed leaf blades and of this translocated 14c, 28~ was above the node of the fed leaf, 38~ in the stem below the node, 28~ in the roots and 7~ in the petiole. As well, in the irradiated plants, a smaller per cent (6~) of the total 14 C recovered was exported out of the source leaf blades. Of this translocated 14c , a smaller per cent (20~) was found in the apical region above the node of the source leaf and a higher per cent (45~) was recovered from the stem below the node and in the petiole (11~). The per cent of exported 14 C recovered from the root was unaffected by the radiation. Replacement of the shoot apex with 20 ppm IAA immediately following irradiation, only J partially increased the magnitude of translocation but did completely restore the pattern of distribution to that observed in the non-irradiated plants. From supplementary studies showing a radiationinduced reduction of photosynthetic rates in the source leaf and a reduction of the cumulative stem and leaf lengths in the apical sink region, the observed effects of radiation on the translocation process have been correlated to damage incurred by the source and sink regions. These data suggest that the reduction in the magnitude of translocation is the result of damage to both the source and sink regions rather than the phloem conducting tissue itself, whereas the change in the pattern of translocation is probably the result of a reduced rate of 14C-assimilate movement caused by a radiation-induced decrease of sink metabolism, especially the decrease in the metabolism of the apical sink.

Seasonal variation in hatching pattern and chick survival in the ring-billed gull Larus delawarensis

The general objective of my study was to monitor proximate causes and seasonal patterns of hatching asynchrony and chick survival in the Ring-billed Gull (Larus delawarensis). Two different plots were set up at a Ring-billed Gull colony near Port Colborne, Ontario in the summer of 1992. One group was from 'peak' nesting pairs (clutches initiated between 15 April and 1 May); a second group was from 'late' nesting pairs (clutches initiated between 9 .. 22 May). Despite equal intra-clutch egg laying intervals between the peak and late periods, intra-clutch hatching intervals lengthened as the season progressed (ie. hatching became more asynchronous). Clutches from both periods were monitored for nocturnal attendance and brood patch development of parents was monitored during the egg laying period. Late nesters were characterized by an absence of nocturnal desertion, substantial brood patch defeatheration at clutch initiation and a reduction in the number of chicks fledged per pair. Chick survival to 25 days (taken as fledging) reflected patterns of chick mass at brood completion and five days post-brood completion, in peak clutches. In late clutches, survival was poor for all chicks and, was partially independent of hatching order, due in part to stochastic events such as Herring Gull predation and adverse weather. In both the peak and late periods, last-hatched C-chicks realized the poorest survival to fledging among brood mates. An artificial hatching pattern (manipulated synchrony) and an artificial hatching order were created, in three-chick broods, through a series of egg exchanges. In peak and late clutches manipulated to hatch synchronously (s; 24 h): C-chick survival to fledging did not differ from the survival of A- and B-chicks, in the peak period. In the late period, the survival of C-chicks was significantly lower than that of A-chicks. In peak clutches manipulated such that chicks from last-laid eggs (C-chicks) hatched 24 h - 48 h ahead of the A- and B- chicks, C-chick survival was greater than in controls. Within those broods, C-chicks survived better on average than both A- and B- chicks.

Educating for Community Resilience: How the Work of Thomas Homer-Dixon and JohnDewey's Pattern of Inquiry Can Help Us Prepare for the Ecological and Social Challenges of the 21st Century

Scientists have overwhelmingly concluded that global warming occurs as a consequence of human activities and that climate change, combined with the depletion of resources, could have catastrophic consequences for the human civilization later this century. However, in political circles and in the public sphere these conclusions are not taken seriously, or they are laid aside for future generations to deal with; at the same time, significant efforts are being deployed to discredit the scientific evidence. In this thesis I have studied the positions of climate scientists as well as those of climate change deniers, and I also examined how their points of view are likely to impact the interests and habits of corporations and citizens. The work of Thomas Homer-Dixon was used as an important source for analyzing the complex interaction between our natural, economic, and social systems, and John Dewey's pattern of inquiry provided the theoretical foundation for an analysis of the current crisis and its possible solutions. No concerted action to deal with climate change has yet been taken by the leaders of the Western world; I corroborated data from four reliable sources (Hansen, 2009; IPCC, 2007; Lynas, 2007; Steffen, 2011) regarding several development scenarios and their likely consequences on greenhouse gas emissions, and I concluded that a future temperature increase of more than 2°C appears now as unavoidable. In the light of this conclusion I argue that education for increasing the resilience of smaller communities is a realistic alternative that can offer some hope in dealing with the challenges ahead.

Incorporating complex cells into neural networks for pattern classification

Dans le domaine des neurosciences computationnelles, l'hypothèse a été émise que le système visuel, depuis la rétine et jusqu'au cortex visuel primaire au moins, ajuste continuellement un modèle probabiliste avec des variables latentes, à son flux de perceptions. Ni le modèle exact, ni la méthode exacte utilisée pour l'ajustement ne sont connus, mais les algorithmes existants qui permettent l'ajustement de tels modèles ont besoin de faire une estimation conditionnelle des variables latentes. Cela nous peut nous aider à comprendre pourquoi le système visuel pourrait ajuster un tel modèle; si le modèle est approprié, ces estimé conditionnels peuvent aussi former une excellente représentation, qui permettent d'analyser le contenu sémantique des images perçues. Le travail présenté ici utilise la performance en classification d'images (discrimination entre des types d'objets communs) comme base pour comparer des modèles du système visuel, et des algorithmes pour ajuster ces modèles (vus comme des densités de probabilité) à des images. Cette thèse (a) montre que des modèles basés sur les cellules complexes de l'aire visuelle V1 généralisent mieux à partir d'exemples d'entraînement étiquetés que les réseaux de neurones conventionnels, dont les unités cachées sont plus semblables aux cellules simples de V1; (b) présente une nouvelle interprétation des modèles du système visuels basés sur des cellules complexes, comme distributions de probabilités, ainsi que de nouveaux algorithmes pour les ajuster à des données; et (c) montre que ces modèles forment des représentations qui sont meilleures pour la classification d'images, après avoir été entraînés comme des modèles de probabilités. Deux innovations techniques additionnelles, qui ont rendu ce travail possible, sont également décrites : un algorithme de recherche aléatoire pour sélectionner des hyper-paramètres, et un compilateur pour des expressions mathématiques matricielles, qui peut optimiser ces expressions pour processeur central (CPU) et graphique (GPU).

Identification et modélisation lexicographique des dépendances syntaxiques régies du français: le cas des dépendances nominales

Cette recherche porte sur l’interface entre la sémantique lexicale et la syntaxe, et elle s’inscrit dans le cadre du projet de base lexicale DiCo (acronyme pour Dictionnaire de combinatoire) à l’Observatoire de Linguistique Sens-Texte [OLST] de l’Université de Montréal. Le projet découle d'une volonté d'inscrire de façon concise et complète, à même le dictionnaire, le comportement syntaxique typique à chaque unité lexicale. Dans cette optique, nous encodons la cooccurrence des lexies nominales du DiCo avec leurs actants à l'intérieur d'un tableau de régime lexical (aussi connu sous le nom de schéma valenciel, structure argumentale, cadre de sous-catégorisation, structure prédicats-arguments, etc.), en notant entre autres les dépendances syntaxiques de surface impliquées. Dans ce mémoire, nous présentons les propriétés syntaxiques d'une dépendance nominale du français, celle que nous avons nommée attributive adnominale, de façon à exposer une méthodologie d'identification et de caractérisation des dépendances syntaxiques de surface. Nous donnons également la liste des dépendances nominales régies identifiées au cours de ce travail. Par la suite, nous exposons la création d'une base de données de régimes généralisés du français nommée CARNAVAL. Finalement, nous discutons des applications possibles de notre travail, particulièrement en ce qui a trait à la création d'une typologie des régimes lexicaux du français.

Développement d’un modèle centré sur l’individu des déplacements du caribou, du loup et de l’orignal, et de leurs interactions, en forêt boréale aménagée

Le caribou forestier est une espèce menacée au Canada, la principale hypothèse au déclin des populations étant l’intensification de la prédation provoquée par les perturbations anthropiques du paysage. Afin de faire face à cette situation, il est nécessaire d’étudier et comprendre l’impact de l’environnement sur les interactions prédateur-proies entre le caribou et le loup, ainsi qu’avec l’orignal, qui est sa principale proie alternative. Pour cela, cette thèse présente la conception d’un modèle centré sur l’individu des déplacements de ces trois espèces en fonction de leur environnement, dont résulteront les interactions prédateur-proies. Afin de permettre l’application de ce modèle sur de longues périodes, et donc pour un environnement changeant, une méthodologie a été développée, qui s’articule atour de deux aspects principaux. Tout d’abord, la notion de niveaux d’émergence est introduite, permettant d’ordonner les comportements observables du système selon leurs interdépendances, afin de choisir comme trait du modèle un com- portement correspondant au domaine d’applicabilité visé. Ordonner les comportements selon leurs niveaux d’émergence permet également d’identifier la redondance entre les patrons, qui peut être à l’origine d’un phénomène de sur-apprentissage lorsqu’ils sont utilisés lors de la calibration. Dans un second temps, un nouveau protocole pour la calibration et la validation du ou des traits choisis à l’aide des niveaux d’émergence, nommé réplication de système basé sur l’individu (Individual Based System Replication - IBSRtion) est également présenté. Ce protocole met l’emphase sur la modélisation directe, contrairement au principal protocole existant, la modélisation orientée patrons (Pattern Oriented Modelling - POM), et permet une approche empirique en générant artificiellement des données non disponibles ou ne pouvant être récoltées par des études de terrains. IBSRtion a également l’avantage de pouvoir être intégrée dans POM, afin de contribuer à la création d’une méthodologie universelle pour la conception de modèles centrés sur l’individu. Le processus de conception de ce modèle aura entre autre permis de faire une synthèse des connaissances et d’identifier certaines lacunes. Une étude visant à palier le manque de connaissances satisfaisantes sur les réponses comportementales à court-terme des proies face au risque de prédation a notamment permis d’observer que celles-ci sont une combinaison de comportements chroniques et éphémères, et que les mécanismes qui en sont à l’origine sont complexes et non-linéaires. Le résultat de ce travail est un modèle complexe utilisant de nombreux sous-modèles, et calibré de façon empirique, applicable à une grande variété d’environnements. Ce modèle a permis de tester l’impact de l’enfeuillement sur les relations prédateur-proies. Des simulations ont été effectuées pour différentes quantités d’enfeuillement, suivant deux configurations spatiales différentes. Les résultats de simulation suggèrent que des plans d’aménagement considérant également l’habitat de l’orignal pourraient être bénéfiques pour le caribou forestier, car ils permettraient d’améliorer la ségrégation spatiale entre les deux espèces, et donc entre le caribou et le loup. En le couplant avec un module de naissances et de morts naturelles ainsi qu’un modèle d’évolution du paysage, ce modèle permettra par la suite d’évaluer l’impact de plans d’aménagement forestier sur la viabilité des populations de caribou forestier.

Is social phobia characterized by a distinct interpersonal pattern?

Traditionnellement, le construit de la phobie sociale a été défini selon une vision intrapersonnelle, en tant que trouble de l’anxiété. Une autre conception se propose de la définir d’un point de vue interpersonnel, comme un pattern global d’autoprotection. L’objectif principal de cette thèse est de tester des hypothèses tirées du modèle interpersonnel de la phobie sociale. Deux études, présentées sous forme d’articles, ont permis d’examiner si des patterns spécifiques d’autoprotection, tels que l’impuissance et la soumission, caractérisent le mode de fonctionnement des phobiques sociaux. Les études ont également évalué si l’autoprotection et l’anxiété sont interreliées. Pour la première étude, les patterns interpersonnels de 132 phobiques sociaux, évalués à l’aide d’une mesure dérivée du Circumplex interpersonnel, ont été comparés à ceux de 85 individus célibataires ayant une dysfonction sexuelle et 105 sujets normaux. La relation entre les patterns d’autoprotection, l’anxiété sociale, la détresse générale et le fonctionnement social a également été examinée chez les phobiques sociaux. La seconde étude a permis d’examiner l’évolution des patterns d’autoprotection ainsi que de l’anxiété sociale, de la détresse générale et du fonctionnement social, chez 85 phobiques sociaux à quatre moments : avant et après un traitement d’approche interpersonnelle, ainsi qu’aux relances de six mois et d’un an. L’étude a également comparé les participants en rémission et ceux satisfaisant les critères de la phobie sociale un an suivant la fin du traitement. Les résultats suggèrent que les patterns d’impuissance et de soumission sont caractéristiques de la phobie sociale. Plus précisément, ces patterns décrivent davantage les comportements des phobiques sociaux plutôt que ceux des groupes de comparaison. De plus, une réduction significative de l’autoprotection a été notée au post-traitement et maintenue jusqu’au suivi d’un an, surtout chez les participants en rémission.En outre, une relation entre l’autoprotection, l’anxiété sociale et la détresse générale a été mise en évidence chez les phobiques sociaux. Une amélioration de l’anxiété, de la détresse subjective et du fonctionnement social cohérente avec la dissolution des patterns d’autoprotection a également été obtenue au post-traitement. En conclusion, les résultats des deux études appuient une conception interpersonnelle de la phobie sociale.

Consumption Expenditure Pattern of Scheduled Caste Households of Kerala: a Study of Idukki District

The present study made an attempt to analyze the socio-economic background and the consumption pattern of scheduled caste households in Idukki district. The objectives of the study are to examine consumption pattern among the scheduled cast population, differences in the average consumption expenditure of different decile groups, consumption expenditure elasticity of items, variations in expenditure of SC households on food, non-food and total expenditure and to examine the association between consumption expenditure and variables such as income, education, occupation and area of residence. The study reveals that the Monthly Per Capita Expenditure of scheduled castes population in rural Kerala is lower than that of the general population. Average household size is higher in rural sector for Scheduled Caste in Kerala as well as all-India. The per capita expenditure of Scheduled Castes of rural Kerala is found to be much lower than that of general population. The study has found that the levels of livings of the Scheduled Castes are far the below the expectations. Large percentage of the Scheduled Caste belongs to the lower income groups. This is due their very low economic status and the consequent employment prospects in low paying occupations. The consumption standards of the majority of Scheduled Castes are found much below that of General population. Effective implementation of the Schemes for their economic upliftment is needed for improving their consumption standards, Minimum Wage Act in the case of agricultural labourers etc. are some of recommendations on the basis of this study.

Array pattern nulling by element position perturbations using a genetic algorithm

A genetic algorithm has been used for null steering in phased and adaptive arrays . It has been shown that it is possible to steer the array null s precisely to the required interference directions and to achieve any prescribed null depths . A comparison with the results obtained from the analytic solution shows the advantages of using the genetic algorithm for null steering in linear array patterns