Th.--Chim. quantique--Toulouse 3, 1977. N°: 757.

Earlier studies suggest that emotion affects long duration estimates of 3-7 seconds and more, but how emotions affect shorter events is not well known. The aim of the thesis was to investigate how emotion, in terms of emotional Valence and Arousal, affects subjective time estimates of short (sub-second) and long (half-a-minute) durations. Participants (N= 26) were exposed to neutral and emotive video clips resembling the International Affective Picture System (IAPS; Bradley, 1995) while making time discrimination judgments (short duration estimates: PSE). Afterwards they made long duration estimates (Long Time Estimates: LTE) and ratings of Valence and Arousal of every video clip. Significant results were that Arousal affected LTE estimates, with longer LTE estimates, the higher the Arousal level. The results indicate that Arousal, but not Valence, affects subjective time perception both of short and long durations. / Tidigare studier antyder att emotioner påverkar uppskattningen av långa durationer på 3-7 sekunder, men hur emotioner påverkar kortare durationer är mindre känt. Studiens syfte var att undersöka hur emotioner, i form av emotionell Valens och Arousal, påverkar subjektiva tidsestimat av korta (sub-sekund) och långa (halv-minuts) durationer. Deltagare (N= 26), exponerades för stimuli i form av neutrala och emotionellt laddade videosekvenser utvalda att efterlikna the International Affective Picture System (IAPS; Bradley, 1995) och utförde samtidigt intervalldiskriminationer (korttidsestimat: PSE). Efteråt utförde de långa durationsestimat (långtidsestimat: LTE) och skattningar av Valens och Arousal för samtliga videoklipp. Signifikanta resultat var att Arousal gav längre durationsskattningar för LTE estimaten, med längre LTE estimat, ju högre Arousal-nivå. Resultaten indikerar att Arousal, men inte Valens, påverkar subjektiv tidsuppfattning för både korta och långa durationer.

The typical form for a molecular mechanics force field consists of a foundation of pair-wise terms to describe bonded and non-bonded atomic interactions, with multi-body correction terms to deal with the limitations of pair-wise terms. I present here the first attempts of a molecular mechanics model that is founded on multi-body terms, which are based on the Bond Valence Model (Brown, 2002) and recent developments in the Vectorial Bond Valence Model (Bickmore et al., 2013a; Harvey et al., 2006). I calibrated these models on pressure vs. energy curves for a set of SiO2 polymorphs. The average deviation for the best-fit iteration, with only six adjustable parameters was ±1.98 kcal/mol.

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This thesis is a partial investigation of instabilities in the interstellar gas which are driven by a coupling between the ambient radiation field and the gas, and which do not arise when this coupling is missed out. The modes of couplings considered are, firstly, the attenuation of the radiation with the concomitant effects on the temperature, density and composition of the gas, in various combinations. Secondly, velocity dependent effects are examined in various circumstances and thirdly, radiation pressure, not included in the other two, is looked at in the simple case in which temperature and compositional changes are excluded. The explanation of why these instabilities may be of interest, and an outline of the extent to which similar instabilities have been investigated, is given in Chapter 1. Chapter 2 gives details of the basic equations used in the case in which the absorption line shape is ignored. Many of the equations are used in the other chapters. The equations are linearised in perturbations of the density, temperature, radiation field and composition, and the resulting dispersion relationship is found for a harmonic perturbation. Because of the attenuation term in the radiative transfer equation, the polynomial has complex coefficients. In Chapter 3 we investigate the properties of the roots of a complex polynomial by an extension of Routh's methods, and derive a set of criteria to determine the number of roots which have positive real part. These roots correspond to exponentially growing perturbations, or, in other words, they correspond to instabilities. Later in the chapter we apply these methods to Field's dispersion relationship for thermal instabilities and derive many of his conclusions in a fairly simple way. By a slight extension the method yields estimates of the growth times of the instabilities. Some related situations are also examined in a similar way. After the detour of Chapter 3, Chapter 4 gives details of some models of the heating and cooling of the interstellar gas as well as of the reactions to be considered, namely the formation and destruction of H₂ and of carbon ions. Some of the limitations of the models are also discussed and the roots of the dispersion relation are given for different values of the parameters. New instabilities do appear; for H₂ their timescales of growth are rather too long to be of interest; for carbon no short timescale instabilities are discovered. Chapter 5 gives similar details for a system of pure hydrogen gas which may be of interest in studies of the formation of the first generation of stars. In Chapter 6 there is a criticism of an earlier work by Schatzman on a similar subject, in which it is shown that his analysis was wrong. Chapter 7 deals with a new possibility, namely that, as the gas moves, photons will be seen to be shifted in frequency and so the molecules will be exposed to a new set of destructive photons at frequencies which have not been selectively absorbed in the unperturbed gas. First the simplest case, that in which the temperature is unperturbed, is treated analytically. The attenuation of the radiation field is not considered. The effectiveness of this doppler-induced effect depends upon both the absorption profile and the radiation spectrum; these factors as well as temperature perturbations are included next. Both line absorption and continuum absorption are considered. The former is used to investigate the stability of the interstellar gas and of pure hydrogen gas, where hydrogen molecules are dissociated by line absorption; the latter is used in connection with HII regions and also the interstellar gas where the photodissociated species are hydrogen atoms and neutral carbon respectively. Radiation pressure was not included in the previous chapters but in Chapter 8 a modified version of Field's theory of instabilities driven by radiation pressure is presented. The new feature is that the frequency dependence of the absorption coefficient is included in the equations and this, in the case of a flat radiation spectrum, leads to an exact cancellation of the dominant term in Field's equation. Several restrictive features of Field's conclusions are thus modified and seem to make this instability rather more useful in the study of instabilities in the interstellar gas than it appeared in Field's work.

In his 1757 essay “Of Tragedy”, Hume reflected on a curious puzzle about emotions. Sometimes people seek out emotions or experiences that are typically negative and associated with displeasure or pain. People often desire to watch horror films that will make them scared or listen to music that will make them sad. Some people even engage in the pursuit of negative emotions on a regular basis such as in the case of thrill-seeking. In this paper my goal is to update Hume’s puzzle with empirical evidence from the affective sciences and argue for two conclusions. First I will argue that Hume’s puzzle still runs deep. Though some recent scientific and philosophical accounts of emotions have tried to solve it, they have thus far failed. Second I attempt to construct a psychological account that solves the puzzle. Instead of focusing on how emotions are generated as previous theories have done, I argue that what is important is how emotions are regulated.

In architectural and sculptural practice, the eventual goal is constructing the shapes that have been designed. Due to fabrication considerations, shapes with planar faces are in demand for these practices. In this thesis, a novel computational modeling approach to design constructible shapes is introduced. This method guarantees that the resulting shapes are planar meshes with 3-valence vertices, which can always be physically constructed using planar or developable materials such as glass, sheet metal or plywood. The method introduced is inspired by the traditional sculpture and is based on the idea of carving a mesh by using slicing planes. The process of determining the slicing planes can either be interactive or automated. A framework is developed which allows user to sculpt shapes by using the in- teractive and automated processes. The framework allows user to cut a source mesh based on its edges, faces or vertices. The user can sculpt various kinds of developable surfaces by cutting the parallel edges of the mesh. The user can also introduce in- teresting conical patterns by cutting dierent vertex, edge, face combinations of the mesh.

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