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Made available in DSpace on 2015-04-17T14:49:41Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1572748 bytes, checksum: 77638fe3cad1c3241c694bca4dc273ac (MD5) Previous issue date: 2014-11-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Older adults represent a segment of population that has more increased in recent years. In Brazil, estimates for next 20 years indicate that elderly population will exceed 30 million people, which can reach nearly 13% of population. Regular physical activity provides one of most opportunities for improving quality of life, improve physical condition and reduce disability and functional limitations of elderly people. The increasing of elderly population has raised need to understand changes that occur in this stage of life, as well as their implications, since, during aging, there are several physiological changes that can affect perception of food for older consumers. For these reasons, present study aimed to evaluate taste sensitivity in elderly people practitioners of physically active, since little is known about sensory responses provided by this group. Threshold test was used to determine detection threshold for salty and sweet flavors in 40 young adults (18-38 years), 40 elderly practitioners of regular physical activity (60-84 years) and 40 elderly no activity practitioners physical (60-87 years). Women accounted for 90% in the group of elderly practitioners of physical activity and 60% of non-elderly practitioners, feature explained by aging feminization process. Physically active elderly had 4.12 mMol thresholds for salty and 6.20 mMol for sweet taste, values close to the group of young adults surveyed and below values found in other studies that worked with sensory perception in the elderly. There were significant minimization of sensory changes of salty and sweet taste in elderly practitioners of physical activity, providing to this group sensorial perception capacity similar to young adults group. Physical activity contributes in some ways to the best development of sensorial perception of older people who practice physical activity, a positive factor for both active development of that group and to its perceptual capacity. / Indivíduos da terceira idade representam um dos segmentos da população que mais tem aumentado nos últimos anos. No Brasil, as estimativas apontam para os próximos 20 anos que a população idosa irá exceder 30 milhões de pessoas, o que pode chegar a representar quase 13% da população. A atividade física regular proporciona uma das maiores oportunidades para se melhorar a qualidade de vida, melhorar as condições físicas e reduzir a incapacidade e limitações funcionais dos idosos. O crescente aumento da população idosa vem despertando a necessidade de se compreender as mudanças que ocorrem nessa fase de vida, bem como suas implicações, uma vez que, durante o envelhecimento, ocorrem diversas transformações fisiológicas que podem afetar a percepção de alimentos por consumidores idosos. Por esses motivos, o presente estudo teve como objetivo avaliar a sensibilidade gustativa em idosos praticantes de atividade física, uma vez que pouco se sabe sobre as repostas sensoriais fornecidas por esse grupo. Foi utilizado o teste de limite para determinar os limiares de detecção para os sabores salgado e doce, em 40 adultos jovens (18-38 anos), 40 idosos praticantes de atividade física regular (60-84 anos) e 40 idosos não praticantes de atividade física (60-87 anos). As mulheres representaram 90% no grupo dos idosos praticantes de atividade física e 60% dos idosos não praticantes, característica explicada pelo processo de feminilização do envelhecimento. Os idosos praticantes de atividade física apresentaram limiares de 4,12 mMol para o gosto salgado e 6,20 mMol para o gosto doce, valores estes próximos aos do grupo dos adultos jovens pesquisados e abaixo dos valores encontrados em outros estudos que trabalharam com percepção sensorial em idosos. Houve minimizações significativas das alterações sensoriais do gosto salgado e doce em idosos praticantes de atividade física, proporcionando a este grupo capacidade de percepção sensorial semelhante à de adultos jovens. A atividade física contribui de certa forma no melhor desenvolvimento da percepção sensorial dos idosos que praticam atividade física, sendo um fator positivo tanto para o desenvolvimento ativo desse grupo como para sua capacidade perceptiva.

L'appellation ‘desserts laitiers neutres' regroupe de nombreux produits de composition similaire mais de structure et de texture différente. Trois de leurs composants et leurs interactions définissent leur structure : l'amidon, les carraghénanes et les protéines de lait. L'objectif de cette thèse était de mieux appréhender les mécanismes physico-chimiques impliqués dans la mise en place de la structure de ces produits et leur impact sur la perception sensorielle.Ce travail s'est focalisé sur les interactions entre l'amidon et les carraghénanes en présence ou non de protéines de lait. De l'amidon modifié de maïs cireux, du lait écrémé reconstitué et des kappa-carraghénanes ont été utilisés. Différentes interactions ont été mises en avant par l'utilisation d'outils rhéologiques et microscopiques. En mélange binaire le carraghénane s'adsorbe sur le granule d'amidon gonflé. Cette interaction dépend de la densité de charge, et de la masse moléculaire du carraghénane utilisé. En mélange ternaire le carraghénane interagit préférentiellement avec les micelles de caséines et ce quel que soit le moment ou le lait est ajouté (avant ou après empesage de l'amidon). Cette modification de l'ordre d'incorporation des ingrédients permet d'obtenir des produits de microstructures différentes. Dans les deux cas les granules d'amidon sont inclus dans un réseau carraghénanes / micelles de caséines mais les caractéristiques de ces deux phases (amidon et carraghénanes / micelles de caséines), responsables de la structuration des produits, sont modifiées. Afin d'en évaluer l'impact sur la perception sensorielle de crèmes, neuf produits de formules identiques mais assemblés différemment ont été fabriqués. Un tri libre, suivi d'un classement des groupes sur des termes discriminants à consonance personnelle, ont été mis en place. Des différences entre les produits ont été perçues. Ces différences ont été décrites par des termes de texture corrélés à des mesures instrumentales de texture.Ce travail a permis de mettre en avant les mécanismes physico chimiques déterminants dans la mise en place de la structure ainsi que leur potentiel impact sur les propriétés sensorielles de produits de type crèmes desserts. Ces connaissances pourraient être mises à profit dans des démarches de conception raisonnée ou de rétro ingénierie pour formuler de nouveaux produits. / Neutral dairy desserts are composed of a large diversity of products of similar composition but different structures and textures. Their structure set up is defined by the interactions between three of their quantitatively minor components: starch, milk proteins and carrageenan. The objective of this PhD project was to better understand the chemical-physics mechanisms beyond the neutral dairy desserts structure set up and their impact on the sensory perception of the product.The study focused on single, binary and ternary mixtures containing starch. It was performed with a modified waxy maize starch, reconstituted skim milk and kappa carrageenan mostly. Using rheological and microscopic tools, different interactions were highlighted. In binary mixtures, carrageenan was found to adsorb on the starch granules. A specific study on those interactions pointed out that they depended on carrageenans' charge density and molecular weights. In ternary mixtures, preferential carrageenan / casein micelles interactions in comparison to starch / carrageenan ones were pointed out even when milk proteins were added after starch pasting in a carrageenan solution. The addition of milk before or after starch pasting led to products of same formula but different microstructures. Starch granules were in both cases embedded in a carrageenan / casein micelles network still, the starch granules states or characteristics and the network formed differed. Dispersed starch and carrageenan / milk phases were defined as the key structure parameters of neutral dairy desserts. To assess their impact on sensorial perception, nine products of same formula but built differently were produced. The evaluation was done by subjects by means of a free sorting task followed by a ranking task on free discriminating terms. Sensory differences were found between the products. These differences were characterized and correlated with instrumental attributes.This work permitted to collect numerous data on chemical-physics properties, link them to the structure set up and to their potential impact on sensory properties of dairy creams. All this knowledge would be easily used to improve tailor food development and particularly to formulate new dairy cream texture through a reverse engineering approach.

The biological energy concepts used by Freud to account for unconscious mental processes in psychoanalysis are discredited by modem biological findings. As a result, different psychoanalytic schools developed new foundational theories in order to verify unconscious mentation. The present study argues that these theories are unsuccessful for two main reasons. Firstly, replacing Freud's drive energy theory with other equally hypothetical foundational constructs does not solve the problem of finding proof for the existence of unconscious mentation. Secondly, the clinical psychoanalytic definition of unconscious mentation as imaginary, internally generated processes, autonomous from the external world is misguided. External sensory data may play a formative role in producing unconscious mentation. In particular, neurobiological findings on sensory data encoding and storage in human infants may throw light on the nature of unconscious processes. The present study therefore compares ideas derived from Lacanian psychoanalysis with neuropsychological memory and infant research findings to ascertain whether unconscious mentation is linked to the memory encoding of sensory data in infants. This analysis is in tum contrasted with a more contemporary psychoanalytic synthesis of findings on infant memory and unconscious mentation (Lichtenberg, 1989, Lichtenberg, Lachmann, and Fosshage, 1992). The latter theory identifies connections between unconscious mentation and the encoding of sensory memories in infancy, but does not connect the episodic and procedural memory constructs used in this account to specific neurolo·gical mechanisms in the brain. The present study's original contributions therefore involve firstly connecting the development of aversive episodic and procedural memories to neurological mechanisms in the brain during the period between birth and 28 months of age. Secondly, this memory model suggests that the storage of aversive memories in infancy has lasting unconscious motivational significance for subjects. Presymbolic memories may unconsciously manipulate conscious attention and memory retrieval in verbal subjects, inviting comparison with the psychoanalytic concept of dynamic unconscious mentation. Thirdly, the presymbolic memory model contributes towards a novel understanding of false memories of childhood sex abuse, and the dissociation of real traumatic memories that occur in many cases of Post Traumatic Stress Disorder. / Psychology / D.Litt. et Phil. (Psychology)

This thesis paper explores barefoot and minimalist running in Ottawa, Ontario and Boulder, Colorado. The objective has been to answer the following questions: how can we understand barefoot and minimalist style running as cultures, how are barefoot and minimalist style running being done in different ways, how do the senses play out and create nuances between barefoot and minimalist style runners. I argue barefoot and minimalist running are distinct cultural forms. I applied an Ingoldian notion of culture that contends cultures are generative, relational, temporal and improvisational. I conducted a multi-site study and I interviewed participants, as well as conducted participant observation. My findings reveal that the different sensations experienced by the two styles of running make them meaningful in different ways. These different sensations and ways of meaning create nuances between barefoot and minimalist running and differentiate them and as a result, there are found to become different cultural forms.

L'un des principaux objectifs des neurosciences est de comprendre comment les fonctions cognitives sont codées par la dynamique des grands réseaux neuronaux. L'étude de la perception sensorielle a principalement été axée sur l'enregistrement de l'activité neuronale induites par des stimulations sensorielles. Une approche alternative réside dans l'utilisation des illusions sensorielles. Ainsi, la perception sensorielle peut avoir lieu en l'absence de stimulation physique externe. Nous avons utilisé une approche multidisciplinaire combinant l'imagerie calcique à deux photons, le comportement moteur et l'optogénétique. Nous avons pu montrerque la larve de poisson zèbre est capable de percevoir " l'effet après mouvement " (EAM). En utilisant l'optogenetique (halorhodopsine) nous avons été capables d'inhiber les mouvementes oculaires pendant la présentation du stimulus conditionné (SC). Nous avons montré que les mouvements des yeux lors du SC ne sont pas impératifs pour l'induction de l'EAM, ce qui suggère que l'EAM n'est probablement pas d'origine musculaire. En utilisant la microscopie à deux photons nous avons montré une habituation de neurones tectales au cours de l'EAM. Cette habituation se dégrade selon une échelle de temps qui correspond au comportement oculo-moteur, lors de l'EAM. En revanche, les cellules ganglionnaires de la rétine ne sont pas habitués. Ceci indique que le toit optique, mais pas la rétine, joue un rôle prépondérant dans l'induction du EAM. Cette approche multidisciplinaire permet de comprendre de façon plus approfondie les mécanismes neuronaux sous-jacents au EAM, et de spéculer sur le corrélat neuronal de la perception du mouvement. / One of the main goals in neuroscience is to understand how cognitive functions are encoded by the dynamics of large neuronal networks. The main stream to study sensory perception has mainly focused on sensory stimulation and neuronal recordings of the induced neural responses. An alternative approach is the use of sensory illusions, in which sensory perception take place in the absence of physical external stimulation. For this purpose, we have used a multidisciplinary approach combining the zebrafish larva as the experimental model, two-photon calcium imaging, motor behavior and optogenetics. We showed that the zebrafish larva is capable of perceiving motion after-effect (MAE). Using optogenetics (halorhodopsin) to prevent eye movements during the presentation of the conditioning stimulus (CS), we showed that pursuit eye movements during CS are not imperative for the induction of MAE, suggesting that neither muscular fatigue nor eye-muscle proprioception feedback play a role in the generation of MAE. Furthermore, we used two-photon microscopy in combination with transgenic fish expressing GcaMP3 . We first observed that during MAE, neurons in the optic tectum (the largest and highest visual brain center of the larva) were strongly habituated. This habituation later decayed with a temporal scale that matched that of the optomotor MAE-like behavior. In contrast, no significant habituation was observed in the retina, Thus, we suggested that the optic tectum but not the retina plays a role in generation of MAE. Our approach contributed to a more comprehensive view of the neuronal mechanisms underlying MAE, and shed light on the neuronal correlate of motion perception

Objective Deterioration of cutaneous perception may be one reason for the increased rate of falling in the elderly. The stochastic resonance phenomenon may compensate this loss of information by improving the capability to detect and transfer weak signals. In the present study, we hypothesize that subliminal electrical and mechanical noise applied to the sole of the foot of healthy elderly subjects improves vibration perception thresholds (VPT). Methods VPTs of 99 healthy elderly subjects were measured at 30 Hz at the heel and first metatarsal head (MET I). Participants were randomly assigned to one of five groups: vibration (Vi-G), current (Cu-G), control (Co-G), placebo-vibration (Pl-Vi), and placebo-current (Pl-Cu). Vi-G and Cu-G were stimulated using 90% (subliminal) of their individual perception thresholds for five minutes in a standing position. Co-G received no stimulation. The placebo groups were treated with mock stimulation. VPTs were measured twice before the intervention (baseline (BASE) and pre-measurement (PRE)), and once after the intervention (post-measurement (POST)). Results Significant differences were found between measurement conditions comparing BASE and POST, and PRE and POST. VPTs between groups within each measurement condition showed no significant differences. Vi-G was the only group that showed significantly higher VPTs in POST compared to BASE and PRE, which contradicts previous studies. Conclusion We analyzed increased VPTs after subliminal mechanical stimulation. The pressure load of standing for five minutes combined with subliminal stimulation may have shifted the initial level of mechanoreceptor sensitivity, which may lead to a deterioration of the VPT. The subliminal electrical stimulation had no effect on VPT. Significance Based on our results, we cannot confirm positive effects of subliminal electrical or mechanical stimulation on the sole of the foot.

Les purées de fruits sont considérées ici comme des dispersions concentrées de particules végétales déformables et insolubles dans une phase continue aqueuse ou sérum riche en sucre et contenant des pectines solubles. La phase dispersée est constituée de cellules ou d'amas de cellules de parenchyme dont les parois insolubles ne représentent qu'une très faible masse (un peu plus de 1 % p/p) dispersées dans un sérum dont elle sont remplies. La constitution et les propriétés rhéologiques des purées vont dépendre de plusieurs facteurs internes tels que la variété de fruit et l'état de maturité et de facteurs externes tels que les paramètres liées au procédé de transformation (traitement mécanique et thermique). Par ailleurs, la texture est l'un des principaux attributs de qualité des purées et constitue à ce titre une source potentielle importante dans le développement de produits nouveaux. L'objectif général de ce travail a été de mieux comprendre les relations entre les propriétés rhéologiques, structurales et sensorielles des purées de pomme dans la perspective d'identifier des leviers d'action pour le pilotage « à façon » de la texture des produits. La stratégie de recherche a consisté à réaliser l'ensemble de l'étude à partir d'une même lot d'une purée issue d'une seule variété de pomme : Golden Delicious et à identifier les axes majeurs permettant de créer des structures et textures variées. Les trois paramètres structuraux qui ont été modifiés sont : la concentration en parois cellulaires (liée à la quantité de particules de pulpe), la taille des particules et la viscosité de la phase continue. Une technique de séparation - reconstitution couplée à un traitement de broyage ainsi que l'augmentation de la viscosité du sérum ont permis d'obtenir une large gamme de textures et de structures. La construction de deux plans expérimentaux a permis de maîtriser la préparation des produits pour l'étude des relations entre la structure, la rhéologie et la texture des purées. La caractérisation physique et sensorielle a mis en évidence l'importance des paramètres structuraux sur le comportement rhéologique et la perception de la texture des purées. Ainsi la concentration en particules a un effet de premier ordre, suivi par la granulométrie et la viscosité du sérum. L'augmentation de la teneur en particules se traduit directement au niveau de l'état d'encombrement du milieu qui dépend de leur taille. Un traitement mécanique entraîne la séparation des amas des cellules de parenchyme en cellules individualisées, ce changement de structure implique des modifications marquées de propriétés. La caractérisation rhéologique et structurale a permis d'établir des modèles rhéologiques et de mieux comprendre le comportement, l'état et le rôle des particules (molles et déformables) sur la structuration du milieu ainsi que le volume occupé par celles-ci. Cette approche a été complétée et validée par l'observation des dispersions par différentes techniques microscopiques. Les différents régimes de concentration, du régime dilué à l'état d'encombrement et de compaction du régime concentrée des purées ont pu être mis en évidence. Les deux axes principaux qui suffisent à décrire la texture sensorielle d'une purée sont la « consistance » et la « granulosité ». La viscosité de la phase continue a un impact sur la perception de la « granulosité » comme sur la cohésion du réseau particulaire. Les résultats montrent que la texture des dispersions végétales peut être « pilotée » à partir de la maîtrise de quelques grandeurs clés : la concentration en parois cellulaires (pulpe) et la granulométrie des particules complété par la viscosité de la phase continue. De grandes possibilités d'innovation sont ouvertes en jouant sur ces leviers notamment à partir des possibilités offertes au niveau des paramètres du procédé de fabrication. / Fruit purees are considered as concentrated dispersions of deformable and insoluble particles in a continuous phase or serum rich in water, sugar and soluble pectin. The dispersed phase consists of cells or cell clusters of parenchyma tissue and the insoluble cell wall material dispersed in the serum represents a very low weight (~ 1% w/w). The structure and the rheological properties of purees will depend on many internal factors such as the variety and ripeness of the fruit and external factors occurring during the processing (mechanical and thermal treatment). Texture is a key quality attribute of purees and thus constitutes an important potential source for new product development. The main objective of this study was to better understand the relationship between the rheological, structural and sensory properties of apple puree, in order to pilot and control the texture of the products. The study was performed with a single batch of apple puree prepared industrially from fresh mature Golden Delicious. In order to create purees with varied structure and texture, three structural parameters were identified and modified: the cell walls concentration (related to the amount of pulp), the particle size and the viscosity of the continuous phase. A separation-reconstitution strategy joined to a grinding step and the modification of the serum viscosity allowed us to obtain a wide range of products with different structures and textures. The construction of two experimental designs made it possible the controlled preparation of the products so as to study the relatioins between structure, rheology and texture of the apple puree. Physical and sensory characterization highlighted the importance of structural parameters on the rheological behaviour and perception of the texture of the puree. Thus, the concentration of particles is the main parameter influencing these properties, followed by the particle size and the serum viscosity. The increase in particle content translates directly at the “overcrowding” that also depends on the particle size. Mechanical treatment leads to the separation of clusters of parenchyma cells in to individual cells; this change in structure involves marked changes of properties. Rheological and structural characterization made it possible the generation of rheological models and the better understanding of the behaviour, the state and the role of particles (soft and deformable) on the structure of the medium and the volume occupied by them. This approach has been completed and validated by the observation of dispersions by various microscopic techniques. The different regimes of concentration were identified. Texture perception of apple puree can be described basically by their “consistency” and their “graininess”. The viscosity of the continuous phase has an impact on the perception of “graininess” and in the cohesion of the particle network. Our results show that the texture of plant food dispersions can be “mastered” by controlling a few selected key parameters: the concentration of cell walls (pulp) and particle size, completed by the viscosity of the continuous phase. High possibilities for innovation are opened by playing on these parameters that can be modified during the processing.