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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.
1

Caractérisation des étapes de traitement élémentaire du raisonnement conditionnel à l’aide de l’EEG et de la MEG : effet de l’incertitude du conditionnel et des différences interindividuelles / Characterization of elementary processing steps of conditional reasoning using EEG and MEG : effect of uncertainty of the conditional and individual differences

Bonnefond, Mathilde 17 December 2009 (has links)
Le raisonnement conditionnel, fondé sur les énoncés de la forme Si P alors Q, est celui qui a reçu le plus d'attention de la part des psychologues. Les arguments principaux du raisonnement conditionnel, comme le Modus Ponens (MP), sont constitués de trois éléments : la prémisse majeure (Si P alors Q), la prémisse mineure (P) et la conclusion (Q). Ces éléments constituent trois étapes de traitement distinctes. Cependant, la dimension temporelle du raisonnement a été en partie négligée dans la littérature. L’objectif central de cette thèse a été d’explorer cette dimension temporelle à l’aide d’une approche novatrice combinant l’utilisation de la mesure du temps de lecture des prémisses, de l’Electroencéphalographie (EEG) et de la Magnétoencéphalographie (MEG). Nous nous sommes donné trois objectifs : 1) Déterminer la séquence des étapes de traitement élémentaire de l’argument MP ; 2) Déterminer comment l’incertitude d’un conditionnel thématique est prise en compte ; 3) Mettre en évidence les différences interindividuelles de traitement d’un énoncé conditionnel, basique ou thématique, en introduisant l’étude de l’argument AC qui permet de dissocier deux populations : les individus qui acceptent la conclusion de AC et les individus qui la rejettent.L’ensemble des données révèle que tous les individus ont une tendance à se focaliser davantage sur P que sur Q lors du traitement du conditionnel, avec des degrés variables selon les individus. Lorsque la prémisse P (ou Q pour les participants qui acceptent AC) est présentée, elle est intégrée à la prémisse majeure afin de générer une conclusion Q encodée et stockée en mémoire de travail avant d’être comparée avec la conclusion présentée.Lorsque le conditionnel est incertain (conditionnel thématique), cette incertitude sur la suffisance de P pour Q (ou de Q pour P) semble être prise en compte par les sujets au niveau de la prémisse majeure et se manifeste par une attente moins prononcée de la conclusion Q une fois que la prémisse P a été présentée. / The conditional reasoning, based on statements of the form If P then Q, is one which has received the most attention from psychologists. The main arguments of conditional reasoning, as the Modus Ponens (MP), consist of three elements: the major premise (If P then Q), the minor premise (P) and conclusion (Q). These elements constitute three separate processing steps. However, the temporal dimension of reasoning has been partly neglected in the literature. The central objective of this thesis was to explore the temporal dimension by using an innovative approach combining the use of the measurement of premises reading time and of the electroencephalography (EEG) and magnetoencephalography ( MEG). We set three objectives: 1) Determine the sequence of processing steps of the basic argument MP 2) Determine how the uncertainty of a conditional theme is taken into account, 3) Highlight the interindividual differences in treatment a conditional statement, or basic theme by introducing the study of the AC argument, which allows to separate two populations: individuals who accept the conclusion of AC and individuals who reject it. The data reveals that all individuals have a tendency to focus more on P and Q in the processing of the conditional, with varying degrees in different individuals. When the premise P (or Q for participants that accept AC) is presented, it is integrated with the major premise to generate a conclusion Q encoded and stored in working memory before being compared with the conclusions presented. When the conditional is uncertain (Thematic conditional), this uncertainty about the sufficiency of P for Q (or Q for P) seems to be taken into account by the subjects at the major premise and is manifested by an less pronounced expectation of Q conclusion when the premise P has been presented.
2

The Role of Psychophysiology in Forensic Assessments: Deception Detection, ERPs and Virtual Reality Mock Crime Scenarios

Mertens, Ralf January 2006 (has links)
ERPs, specifically the P3, have been proposed as an alternative to traditional polygraphy, with one approach (i.e., Brain Fingerprinting) being promoted as infallible to justify its use on a commercial basis. Concerns have been voiced, however, that such techniques would have to undergo peer-reviewed studies to satisfy validity concerns. Rosenfeld et al. (2004) found, for example, that mental countermeasures were effective in reducing detection rates using an amplitude based, peak-to-peak measure. The present study attempted to replicate and extend Rosenfeld et al.'s study, and to test Brain Fingerprinting's vulnerability to participant manipulation by employing a highly realistic virtual reality crime scenario, multiple countermeasures, and Bayesian and bootstrapping analytic approaches to classify individuals as being guilty or innocent. Participants reported a high degree of realism supporting the external validity of this study and suggesting future uses of virtual environments. Hit rates across statistical methods were significantly lower for standard guilty and innocent participants as compared to previous studies; countermeasures reduced the overall hit rates even further. Brain Fingerprinting was as vulnerable to countermeasures as other statistical measures, and produced a significant number of indeterminate outcomes. Nevertheless, innocent participants remained protected from being falsely accused across statistical methods, consistent with findings of prior studies. Reaction times were determined unsuitable in determining guilt or innocence in this study. Results suggested that ERP based deception detection measures might lack the level of validity required for use in an applied setting.
3

Examining QALY's : analysing the use of quality adjusted life years in the allocation of health care resources

Petrou, Stavros January 1992 (has links)
This thesis examines the use quality adjusted life years (QALY'S) in the allocation of health care resources. It is divided into three broad sections. The first section discusses how health status measurement techniques can be used to derive the utility values incorporated into QALY'S. The second section uses one health status measurement instrument, the Rosser-Kind Classification of Illness States, to estimate the QALY'S gained by patients who have undergone hip and knee joint replacement surgery. It is shown that the Rosser-Kind Classification of Illness States is as effective in measuring the health-related quality of life of these patients as more detailed questionnaires. In addition, it is found that further research is required before any generalisations concerning the acceptability of retrospective data can be made. A third important result is that there are significant improvements in health- related quality of life following both types of surgery, with the highest Rosser- Kind rating scores achieved after the first year following knee replacement surgery and after the second year following hip replacement surgery. The third section of the thesis performs an extensive sensitivity analysis on the widely-quoted cost utility estimates for seven medical procedures, calculated by Gudex (1986). The estimates are shown to be sensitive to Gudex's conversion of health outcome data into the Rosser-Kind Classification, her assumptions concerning the survival period / life expectancy following each of the medical procedures and the selected discount rate. A more in depth analysis is then performed on the cost utility estimate for one of the seven procedures, ceftazidime treatment of cystic fibrosis. It is demonstrated that the health outcome and cost assumptions underlying the cost utility estimate for this procedure are not supported by the medical literature. Finally, the thesis raises a number of issues for discussion.
4

Belief and action

Pehrson, Claud W. P. January 1976 (has links)
The role of "believes" is identified by finding a unique and unparaphraseable use of the term that is integral to the structure of important forms of language. This role can only be roughly indicated here. Roughly, "believes" identifies someone's reasons for doing or thinking something or what he counts as success in certain activities, without committing the speaker to accepting them; and so it allows the possibility of mistake. Standard objections to dispositional accounts are reviewed and found unconvincing. The central difficulty is found to be that dispositional accounts give no satisfactory explanation of the fact what it is (part of) an explanation of action to cite the agent's beliefs. It is argued that causal accounts have the same deficiency, that the role or point of "believes" in language is not satisfactorily explained. It is concluded that neglect of this central question vitlates even the real strengths of these accounts. The relation between different questions about belief is explored, and analogous questions about other cases, especially artefacts, are considered. Explanations of actions are discussed to bring out the role of "believes." This appears in explaining the relation between the "point or purpose" of an action and the actions of which it consists at a lower level of description. "Believes" identifies what governs this relation while allowing the possibility of mistake. Ryle's claims about thinking are considered, and an interpretation of the notion of an adverbial verb is suggested. The central difficulty concerns the cases of the thinking of le Penseur or of Eucild. Although it seems important that we should be able to say what the constituents of thinking are here, we cannot do so, since the relevant vocabulary is not adapted to giving the constituents of anything. These activities have their own "objects" as well as their own criteria of success. Activities, "objects", and criteria of success are bound up together, and do not connect in any simple way with the vocabulary that we try to connect them with in asking what their constituents are. This far from unique. Music provides another relevant example. The last chapters examine various contexts in which "believes" is important. Topics considered are reasons, evaluations, assertions, belief and the will, internationality, and speech-act accounts. In each case particular doctrines are critically examined.
5

Some reactions of methyl octadecenoates and related compounds

Perera, Buvipali Srima January 1972 (has links)
Part I: The Methyl trans-Methyleneoctadecanoates. The sixteen isomeric methyl trans-methyleneoctadecanoates have been synthesised from the corresponding methyl trans alkenoates by the Simmons-Smith reaction, and some of their physical properties examined. Only one isomer (methyl trans-9,10-methyleneoctadecanoates) has previously been reported. The gas liquid chromatographic data are interesting in that on both polar and non-polar columns the cis and trans isomers are well separated. The methyl trans-methyleneoctadecanoates show diagnostic nuclear magnetic resonance signals around 9.8 to 9.6r. The 2,3-; 3,4-; 5,6-; 16,17-; and 17,18- isomers differ from one another, but the remainder are very similar to each other. The mass spectra of some of the isomers were examined but they do not provide much useful information. Our data, along with that previously reported for the corresponding cis isomers (see ref 21), should assist in the recognition of these compounds. For complete identification, however it may be necessary, in addition to examine the mass spectrum of the hydrogenated ester. Part II: Halogenation of Unsaturated Long-chain Hydroxy Compounds. Neighbouring group participation in unsaturated hydroxy compounds occurring during reaction at the unsaturated centre has already been observed in appropriate long-chain compounds during various oxidation reactions and during oxymercuration. The halogenation of certain hydroxyalkenoates, octadecenols and octadecenoic acids has now been examined with a view to finding out if neighbouring group participation occurs during these reactions. The halogenating agents employed were iodine monochloride, bromine and chlorine giving rise to the electrophilic reagents I+, Br+ and C1+ respectively. In most reactions only the simple addition products (vic-dihalides) were observed and these were converted into ene-halides by dehydro- halogenation since the latter have been reported previously in only a few cases. The hydroxyl group was involved in halogenation in only a few instances - mainly in iodochlorination - to give substituted tetrahydrofurans (1,4-epoxides). Lactones were obtained during the halogenation of some unsaturated acids. Attempts to obtain N-heterocyclic compounds by the reaction of long-chain amines were less successful but the conversion of methyl ricinoleate to methyl 12-amino-oleate was satisfactorily achieved.
6

Studies on neuronal 5-HT in a gastropod mollusc, Helix pomatia (L.)

Pentreath, V. W. January 1973 (has links)
This thesis describes information obtained on the structure of 5-HT-containing neurons, on the mechanisms of transport of 5-HT and its precursors into and within neurons, on the nature of the blood supply to the CNS, and on the function of 5-HT-containing neurons within the CNS of Hellix pomatia. In particular data is obtained for the giant serotonin-containing neuron (GSG) in each cerebral ganglion. Dense-cored vesicles of mean diameter 100 nm are present in the perikarya and axon branches of the GSCs. Vesicles of similar appearance are present in the presumed presynaptic endings of the GSCs. Evidence is presented which suggests that such vesicles sequester 5-HT, The fine structure of presumed presynaptic endings making synaptic connections with the GSCs is described. Following exposure to tritiated 5-HT, electron microscope autoradiography showed that silver grains, often in very high concentrations, were located over certain fine axon branches thought to be nerve endings. These processes contained small dense-cored vesicles, which were morpliologically similar to those thought to sequester 5-HT to the perikarya of the GSCs. It is suggested that re-uptake into nerve endings is a mechanism of inactivation of 5-HT in the Following exposure to tritiated 5-HTP, silver grains were observed over the perkarya of the GSCs and other known 5-HT-contalning neurons. There was no indication that 5-HTP was taken up by nerve endings or by non-nervous structures. The accumulation of tritiated tryptophan was less specific; all the neuron perikarya took up this substance. The CMS of H. pomatla is supplied by branches of the anterior aorta. Capillaries from these branches open into a, blood space which is adjacent to, and continuous over the surface of the nervous tissue. Blood passes from this space through the epineural sheath into the body cavity sinuses. Three tissue layers separate the blood spaces from the nervous tissue. These are (i) a luminal endothelium, (ii) a connective tissue layer, and (iii) glial cells. The luminal endothelium and connective tissue are freely permeable to uncharged particles of 10 nm or less. Eloctrophysiological analysis showed that each GSC sends axon branches to muscles in the lips of the animal. Selective stimulation of the GSCs resulted in an increase of electrical activity recorded from these muscles, but no change in their length. This effect was mimicked by 5-HT applied to the muscles. It is suggested that the GSC has a facilitatory effect on the lip muscle potentials.
7

X-ray study of the stacking fault density near the hardness maximum of the Au-Ag-Pd system

Pauley, Cecil Lloyd January 1967 (has links)
The annealed hardness of certain dental alloys has been measured and found to be in relatively good agreement with the existing hardness map. In addition, lattice parameters, stacking fault densities, and spacing change fractions have been determined for those alloys. The lattice parameters were found to deviate negatively from Vegard's Law. For the alloys studied, the maximum deviation of 0.0091 A occurred at 20 weight % Ag. The average stacking fault density for the five alloys was determined as 0.007, which is within the range for values reported for the Pd-Ag system. The average of the spacing change was found to be 0.06. A computer program has been developed to extract the lattice parameter for a given reflection from step scan data by obtaining midpoints of a peak at various heights above background. Line shape analysis has been performed for one specimen, with the result that the deformation fault density thus obtained agrees well with that obtained from the lattice parameter measurements, and a twin fault density of 0.0045 was measured. / Master of Science
8

Irradiated gametes as a means of limited gene transfer in plant breeding

Perryman, A. Linda M. January 1991 (has links)
Following reports that limited gene transfer may be facilitated by making crosses with irradiated pollen, a debate has arisen as to the cause of the observed results. If maternal trends that occurred in the second generation (the M2) were largely due to the persistence of radiation induced damage, then pollen irradiation would be of little value to plant breeders. But if much of the paternal genome had been eliminated, the method could offer breeders a cheap and simple means of transferring just a few characters from one plant genome to another. By carrying out reciprocal irradiated and control crosses, it was shown in this study with barley that mutational damage is not widespread in the M2. However, consistent trends away from the F2 towards the maternal expression were not observed either. When instead the female gamete was irradiated, moderate shifts to the paternal expression did occur. As trends were for increased vigour, mutational damage is unlikely to have been the cause of these observations. By contrast, when irradiated pollen crosses were made between three varieties of potato, the M1 and M2 were consistently lower scoring than the controls. It is suggested that the results may have been different in the two species because polyploids such as the potato may be better able to tolerate radiation damage than diploids such as barley. Gamete irradiation may, therefore, be of little value in polyploid crops. It is recommended that, at least in diploid species, ovule irradiation should be further investigated because not only may it be more effective than its male equivalent, but it may also be easier to perform. Both techniques may be useful in breaking down linkages resistant to conventional crossing.
9

Fattar du vad de säger? : En begriplighetsanalytisk jämförelse mellan Ekot och P3 Nyheter / Did you catch that? : A comprehension analytical comparison of Ekot and P3 Nyheter

Edsö, Maja, Jennische, Johanna January 2012 (has links)
In this study we compare Ekot with P3 Nyheter with a comprehension analytical perspective. The more traditional radio news program Ekot differs from the younger P3 Nyheter in a lot of aspects. One of them is that P3 Nyheter’s primary target group is young people between the ages of 20 to 34. Because of this, P3 Nyheter aim to make their news as adjusted to their young audience as possible. We wondered whether this adaption to please their audience had impact on the comprehension, and wanted to compare P3 Nyheter with Ekot, who does not have a targeted audience but aim to make themselves comprehensible to as many as possible. However, the comprehension analysis was insufficient to us, and we decided to analyze our transcribed newscasts using text analysis as well in order to be able to analyze concepts that the comprehension analysis does not cover, but that we thought was important in our study. We also interviewed representatives from Ekot and P3 Nyheter, to see how they saw their mission and target audience.                       Our study shows that the different news programs practically had the same level of potential comprehension. They had different comprehension obstacles, but neither was better than the other. Thus, the comprehension did not improve despite P3 Nyheter’s adaption to their target group. However, the comprehension did not decline due to the adaption either. P3 Nyheter give their audience so called “infotainment” in a higher degree than Ekot by choosing news items that are closer to entertainment than information. Ekot on the other hand often presents a greater number of news in their newscasts, but rarely illustrate with sounds. The two programs also differ greatly in their vocabulary.
10

A life cycle analysis of the potential role of commercial computer equipment in military trainers as applied to maritime patrol aviation /

Intintolo, John A., January 1992 (has links)
Report (M.S.)--Virginia Polytechnic Institute and State University. M.S. 1992. / Vita. Abstract. Includes bibliographical references (leaves 112-113). Also available via the Internet.

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