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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

Formation of Copper-Salivary Component Complexes and Its Effect on Sensory Perception

Hong, Jae Hee 22 November 2006 (has links)
Copper in drinking water elicits a persisting bitter, metallic, or astringent taste. Characteristics and perception mechanisms of copper sensation have not been fully understood. Saliva is assumed to influence copper sensations via binding of salivary electrolytes or proteins with copper. The interaction between salivary components and copper is thought to influence sensory perception by affecting volatility of aroma compounds, de-lubricating salivary proteins, and by controlling solubility of copper. A recent study suggested that intensity of copper taste may be dependent on the amount of solubilized copper, which increases at lower pH. This research was performed to identify 1) the temporal sensory characteristics of copper; 2) the effect of pH on perception of copper sensation; 3) the nature of copper-protein interaction and its impact on sensory perception. The effect of copper on the volatility of aroma compounds and the role of copper-protein interaction in volatile chemistry were investigated using a model mouth system containing artificial saliva at different pH levels. Headspace concentration of each volatile was measured using SPME-GC analysis. Copper (2.5 mg/L) in the model system increased headspace concentration of volatiles (hexanal, butyl acetate, 2-heptanone, and ethyl hexanoate, 0.5 microL/L each) at pH 6.5, but no change in volatility was observed at pH 7.0. At pH 7.5, presence of copper in the artificial saliva decreased headspace volatile concentration. Effect of copper on volatiles at pH 6.5 may be due to increased solubility of copper at lower pH. Copper seems to facilitate hydrophobic binding between mucin and aroma compounds at pH 7.5, possibly by exposing hydrophobic sites of mucin. A time-intensity (TI) test was performed to identify the effect of pH on temporal characteristics of copper sensation. Metallic taste, bitterness, and astringency were major attributes of drinking water containing 2.5 mg/L and 5 mg/L Cu. All three attributes were responsible for the lingering aftertaste of copper. TI test results of copper solutions did not show a common TI pattern of astringency that is characterized with slow onset and longer duration time. Increase in pH of water from 5.5 to 7.5 inhibited metallic taste of copper, but did not reduce bitterness and astringency. The level of soluble copper at pH 7.5 decreased by 50 % compared to that at pH 5.5. Soluble copper concentration and temporal profile of sensory attributes of copper solutions at different pH levels suggest that soluble copper species decide the perception of copper sensation by controlling metallic taste. The nature of copper-protein interaction and its implication on mechanisms of sensory perception were studied by investigating binding of copper to high molecular weight fractions of human saliva. At the copper concentration < 10 mg/L, most copper exists as unbound copper form while about 60 % of copper was found in protein fractions or with precipitated salivary debris. This result suggests that copper is in a soluble unbound form in saliva at low concentration (<10 mg/L) and assumed to be available for taste receptors. At higher concentration, copper either becomes insoluble or binds with proteins. Insoluble copper species are thought to cause astringency. When copper was added at the concentration equal to or greater than 10 mg/L, two salivary proteins of molecular weight 29 kDa and 33 kDa formed insoluble complexes with copper. Low molecular weight mucin (MG2), alpha-amylase, basic proline-rich proteins (PRPs), and a protein of MW 45 kDa also bound with copper. In summary, sensations elicited or influenced by copper are thought to be determined by what copper species are dominant in the mouth. Soluble copper species and insoluble copper species are assumed to interact with different sensory receptors, resulting in metallic taste or astringency. This speciation process is influenced by pH conditions, composition of other electrolytes, and organic chelators such as proteins. / Ph. D.
42

A memory model of presymbolic unconscious mentation

Lockhart, Ian Andrew 11 1900 (has links)
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)
43

Language and speech in the phenomenological philosophy of Maurice Merleau-Ponty / Kalba ir kalbėjimas Maurice’o Merleau-Ponty fenomenologinėje filosofijoje

Simonova, Jelena 04 February 2011 (has links)
The thesis reflects on the dichotomy of language and speech. The separation, introduced by Ferdinand de Saussure and successfully interpreted and developed by Merleau-Ponty, is analyzed from a phenomenological perspective where the individual speech appears as live and intentional act; from this perspective, it gains advantages against the language as a system of signs. The problem of the diacricity of the meaning of speech is articulated keeping in mind that sensory perception is also diacritical. Moreover, sensory perception is expressive initially and always correlates to the expressivity of the lived body; therefore, the semantics of the philosophy of Merleau-Ponty represents embodied semantics. The author of the thesis agrees with the insight of Merleau-Ponty and his postulates that artistic painting, literature, and philosophy are forms of speaking whose resources are incrusted in the corporeity of human beings. Representing the extension of gestures and being determined by natural willingness of human beings to say and express something new, such forms of expression disclose the initial relationship of human beings with the world and witness the creativity of the linguistic activities of human beings. Defining the object of the research, it is reasonable to set the philosophical style and unmatched manner of speaking of Merleau-Ponty. It deliberates and substantiates the possibility of individual relationship of every human being with his/her speaking, and opens the... [to full text] / Disertacijoje apmąstoma kalbos ir kalbėjimo dichotomija. Ferdinando de Saussure’o įvesta ir Merleau-Ponty interpretuota bei vaisingai išplėtota perskyra analizuojama todėl, kad individualus kalbėjimas, pasitelkus fenomenologinę perspektyvą, atsiskleidžia kaip gyvas ir intencionalus, – šiuo požiūriu jis įgyja pranašumų kalbos, kaip uždaros ženklų sistemos, atžvilgiu. Kalbėjimo reikšmės diakritiškumo problema darbe artikuliuojama, turint omenyje, kad juslinis suvokimas yra diakritinis. Dar daugiau, juslinis suvokimas pirmapradiškai yra išraiškingas ir visada koreliuoja su gyvenamo kūno ekspresyvumu, todėl Merleau-Ponty filosofijoje semantika yra įkūnyta semantika. Disertacijos autorei pritariant Merleau-Ponty įžvalgai, postuluojama, jog tapyba, literatūra bei filosofija taip pat yra kalbėjimo formos, kurių šaltinis inkrustuotas žmogaus kūniškume. Pratęsdamos gestą ir būdamos apspręstos prigimtinio žmogaus troškimo išreikšti ir pasakyti kažką vis naujai, jos išreiškia pirmapradį žmogaus patiriamą santykį su pasauliu bei liudija kalbinės žmogaus veiklos kreatyvumą. Formuluojant šio tyrimo objektą, tikslinga išskirti ir paties Merleau-Ponty filosofavimo stilių bei ypatingą, analogo neturinčią kalbėjimo manierą. Ji išlaisvina bei pagrindžia kiekvieno žmogaus giliai asmeninio santykio su jo paties kalbėjimu galimybę ir atveria kelią naujai filosofavimo tendencijai, kuri numano žmogiškojo aš savęs bei jo prasmingo pasaulio ap-klausimą. Taigi, sekdama filosofo pavyzdžiu bei... [toliau žr. visą tekstą]
44

Kalba ir kalbėjimas Maurice'o Merleau-Ponty fenomenologinėje filosofijoje / Language and speech in the phenomenological philosophy of Maurice Merleau-Ponty

Simonova, Jelena 04 February 2011 (has links)
Kalba ir kalbėjimas Maurice’o Merleau-Ponty fenomenologinėje filosofijoje Disertacijoje apmąstoma kalbos ir kalbėjimo dichotomija. Ferdinando de Saussure’o įvesta ir Merleau-Ponty interpretuota bei vaisingai išplėtota perskyra analizuojama todėl, kad individualus kalbėjimas, pasitelkus fenomenologinę perspektyvą, atsiskleidžia kaip gyvas ir intencionalus, – šiuo požiūriu jis įgyja pranašumų kalbos, kaip uždaros ženklų sistemos, atžvilgiu. Kalbėjimo reikšmės diakritiškumo problema darbe artikuliuojama, turint omenyje, kad juslinis suvokimas yra diakritinis. Dar daugiau, juslinis suvokimas pirmapradiškai yra išraiškingas ir visada koreliuoja su gyvenamo kūno ekspresyvumu, todėl Merleau-Ponty filosofijoje semantika yra įkūnyta semantika. Disertacijos autorei pritariant Merleau-Ponty įžvalgai, postuluojama, jog tapyba, literatūra bei filosofija taip pat yra kalbėjimo formos, kurių šaltinis inkrustuotas žmogaus kūniškume. Pratęsdamos gestą ir būdamos apspręstos prigimtinio žmogaus troškimo išreikšti ir pasakyti kažką vis naujai, jos išreiškia pirmapradį žmogaus patiriamą santykį su pasauliu bei liudija kalbinės žmogaus veiklos kreatyvumą. Formuluojant šio tyrimo objektą, tikslinga išskirti ir paties Merleau-Ponty filosofavimo stilių bei ypatingą, analogo neturinčią kalbėjimo manierą. Ji išlaisvina bei pagrindžia kiekvieno žmogaus giliai asmeninio santykio su jo paties kalbėjimu galimybę ir atveria kelią naujai filosofavimo tendencijai, kuri numano žmogiškojo aš savęs bei jo... [toliau žr. visą tekstą] / The thesis reflects on the dichotomy of language and speech. The separation, introduced by Ferdinand de Saussure and successfully interpreted and developed by Merleau-Ponty, is analyzed from a phenomenological perspective where the individual speech appears as live and intentional act; from this perspective, it gains advantages against the language as a system of signs. The problem of the diacricity of the meaning of speech is articulated keeping in mind that sensory perception is also diacritical. Moreover, sensory perception is expressive initially and always correlates to the expressivity of the lived body; therefore, the semantics of the philosophy of Merleau-Ponty represents embodied semantics. The author of the thesis agrees with the insight of Merleau-Ponty and his postulates that artistic painting, literature, and philosophy are forms of speaking whose resources are incrusted in the corporeity of human beings. Representing the extension of gestures and being determined by natural willingness of human beings to say and express something new, such forms of expression disclose the initial relationship of human beings with the world and witness the creativity of the linguistic activities of human beings. Defining the object of the research, it is reasonable to set the philosophical style and unmatched manner of speaking of Merleau-Ponty. It deliberates and substantiates the possibility of individual relationship of every human being with his/her speaking, and opens the... [to full text]
45

Mental activity in Descartes' causal-semantic model of sensory perception

Ortín Nadal, Anna Pilar January 2018 (has links)
The aim of this thesis is to defend a reading of Descartes' theory of sensory perception in which, against a widespread interpretation, the mind is not a passive receiver of inputs from the environment, but an active decoder of neural information that contributes to the representational content of ideas. I call this the 'mental activity thesis' and, in the overall picture, I identify it as one of the philosophical implications of the seventeenth-century scientific revolution. Within Descartes' dualism, to offer a theory of sensory perception amounts to describing the interplay between the natural world, the brain, and the mind. Given his mechanistic, micro-corpuscular conception of matter, Descartes developed detailed physiological descriptions of the interaction between external objects and the brain. He envisaged it as an isomorphic relation in which the characteristics of objects are transmitted through the nerves to the brain as patterns of geometrically reduced properties. This process is often read as culminating with the mind being passively affected by a corporeal isomorph. Descartes' doctrine becomes elusive in its mental phase, but the passivity reading, so I contend, remains inadequate. I argue for the mental activity thesis through four claims. First, I subscribe the known view that Descartes is concerned about a version of the mind-body problem that is not equivalent to the problem of substance interaction. It is rather a problem of dissimilarity between mental representations and mechanistic explanations. The question is how the qualitative character of sensory experiences can arise from the quantitative notions of physical science. As a way of emphasising the weight that the problem of dissimilarity has for Descartes' philosophical decisions, I show that it motivates a metaphysically interesting distinction between types of causes for the case of brain-mind interaction. Second, I defend the position that, despite not holding a perfectly unambiguous doctrine, Descartes' introduction of natural signs is the closest that he got to formulating a full-fledged theory of sensory perception. The appeal to natural signs has been normally deemed as metaphorical in the literature. I argue that, on the contrary, it is possible to reconstruct a causal story for brain-mind interaction along the lines of a semantic model based on Descartes' identification of neural events with natural signs. A causal-semantic model emerges as a charitable, plausible reading that reveals the mind as an active interpreter. Third, in light of the mental activity thesis, I read Descartes' late appeal to the innateness of all ideas (notably in the Comments on a Certain Broadsheet) as a strategy to account for a type of representational content needed for sensory ideas that, while produced by the mind, is different from that of his paradigmatic innate ideas. I assist Descartes in exploring how the category of innateness captures mental activity within a causal-semantic theory. Fourth, in the course of this argumentation, and for further support, I address the role of the distinction between primary and secondary qualities in Descartes' theory. I tackle a pervasive objection stemming from his alleged association of the perception of primary qualities with the intellect. By reassessing Descartes' views on mental activity, this interpretation aims at a lucid description of sensory perception that goes beyond the rigid rationalism that is often credited to him.
46

Sensory Ecology Of Acoustic Communication In The Tropical Bushcricket Genus Mecopoda : Mechanisms And Evolution Of Synchrony

Nityananda, Vivek 11 1900 (has links)
In this thesis, I characterise five species of the bushcricket genus Mecopoda with respect to their acoustic signals and morphology and investigate the phenomenon of acoustic synchrony in one of these five species: Mecopoda ‘Chirper’. In several bushcricket species, individual males synchronise their chirps during acoustic interactions. Synchrony is imperfect and the chirps of the males lead or follow each other by a short duration of time. Imperfect synchrony is believed to have evolved in response to female preferences for leading chirps. This model of the evolution of acoustic synchrony, however, depends on assumptions about the physiological mechanism of acoustic interaction between individual males and also on the presence of selective attention to a restricted number of neighbours. Neither of these two assumptions has previously been investigated in the species Mecopoda ‘Chirper’ and the implications of these for the evolution of acoustic synchrony is unknown. Furthermore, the advantage of leading chirps for males in the field, given trade-offs between the advantages of lead and intensity and the spacing of males has not been investigated in any bushcricket. In this thesis, I address these questions using a combination of behaviour, neurophysiology and computer simulations. Five distinct song types of the genus Mecopoda were found in Southern India. Four were morphologically indistinguishable. Some of them were both sympatric and had synchronous breeding seasons. The songs of these five song types ranged from simple short chirps to highly complex songs with multiple components. The temporal patterns of the songs were very distinctive, whereas their spectral features were similar. Component elements of the different songs were distinct despite overall similarity. The song types possibly represent sibling species. The mechanism underlying synchrony in the species Mecopoda ‘Chirper’ differs from previously reported mechanisms in that it involves both a change in the oscillator’s intrinsic rate and resetting on a chirp-by-chirp basis. The form of the phase response curve differs from those of previously reported firefly and bushcricket species including the closely related Malaysian species Mecopoda elongaa. Simulations exploring oscillator properties showed that the outcome of pairwise interactions was independent of initial phase and alternation was not possible. Solo intrinsic chirp period was a relatively good predictor of leading probability. Changing the intrinsic period during interactions could, however, enable males with longer periods to lead during acoustic interactions. In choruses in the field, chirp period and hence lead probability of males had low repeatability with no consistent ‘leaders’ and ‘followers’ across nights. During acoustic interactions, sixty percent of followers called oftener when leaders were not calling. Spacing enabled some softer males to gain areas where they were the loudest of all males in a chorus. Thus followers in choruses potentially have different strategies at their disposal by which they could offset their disadvantage in attracting mates. In neurophysiological experiments investigating selective attention, louder, leading chirps were preferentially represented in the auditory system but the representation of softer following chirps was not completely abolished. Following chirps that were 20 decibels louder than leading chirps were better represented than leading chirps. During acoustic interactions in response to playback, males synchronised with leading chirps even when the following chirps were 20 dB louder. Males did not restrict their attention to louder chirps during interactions but were affected by all chirps above a particular threshold intensity . In the field, males on average had only one or two neighbours whose calls were above this threshold. Selective attention in this species is thus achieved through spacing rather than neurophysiological filtering of softer signals. A simulation that combined these results to investigate the evolution of synchrony, revealed that the strategy of responding to one’s neighbours and synchronising with them was able to invade a population of males that did not respond to their neighbours only upto a point. The responder strategy was also not evolutionarily stable and could be invaded by the non-responder strategy. In both cases, the population stabilised at a point where the number of males with either strategy were approximately equal. This was true even if a different physiological resetting mechanism was assumed. The results also held true across a range of male aggregation patterns and different possible female preference values for time-intensity trade-off and lead windows. Thus it appears that though a responder strategy can spread in a population up to a proportion of approximately 0.5, it cannot completely take over a population, if the only selective advantage to synchronising males is due to female preference for leading chirps.
47

Barefoot Running: Feeling the World Through Your Feet

Warnock, Carly 13 August 2013 (has links)
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.
48

As competências profissionais do orientador de estágio-estudo da percepção dos estagiários e da auto-percepção dos orientadores relativamente às capacidades profissionais, conhecimento desportivo e relações interpessoais, reveladas pelo orientador

Carvalhinho, Luís Alberto Dias January 1999 (has links)
No description available.
49

Perfil de prestação do ponta de lança de alto rendimento em futebol-estudo de caso baseado na comparação do comportamento táctico, técnico do jogador com a percepção do treinador

Sousa, Paulo Antero Cardoso de January 2000 (has links)
No description available.
50

Comparação entre a concepção do treinador e a percepção dos jogadores, face à prestação táctica, individual e colectiva-um estudo de caso numa equipa de Futebol de Juniores A.

Lucas, João Manuel da Costa January 2001 (has links)
No description available.

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