In previous studies truncated models were found to underestimate the air's upward velocity when compared to wind tunnel velocity studies, which may affect particle aspiration estimates. This work compared aspiration efficiencies using three torso geometries: 1) a simplified truncated cylinder; 2) a non-truncated cylinder; and 3) an anthropometrically realistic humanoid body. The primary aim of this work was to (1) quantify the errors introduced by using a simplified geometry and (2) determine the required level of detail to adequately represent a human form in CFD studies of aspiration efficiency. Fluid simulations used the standard k-epsilon turbulence models, with freestream velocities at 0.2 and 0.4 m s-1 and breathing velocities at 1.81 and 12.11 m s-1 to represent at-rest and heavy breathing rates, respectively. Laminar particle trajectory simulations were used to determine the upstream area where particles would be inhaled. These areas were used to compute aspiration efficiencies for facing the wind. Significant differences were found in vertical velocity and location of the critical area between the three models. However, differences in aspiration efficiencies between the three forms was less than 6% over all particle sizes, indicating that there is little difference in aspiration efficiency between torso models.

The objective of this work is to develop an innovative and quantitative method to study cell failure under fluidic pressure to understand cell membrane mechanical properties. Due to lack of experimental data related to cell failure property, the current research focuses on investigating the cell failure using a micro pipette aspiration experiment method to elaborate gradually increasing hydrostatic pressure to the cell causing the membrane to deform and eventually rupture. Based on our observation, the prostate cancer cells (PC-3) deformed into a deflated and flattened shape under higher hydrostatic pressure (249 Pa) while prostate epithelial cells (PrEC LH) cells generate a spherical and rounded shape. The stress along the cell membrane was estimated from the curvature data captured from the 2D microscopic images for each pressure magnitude to quantify the damage before rupture state. From the results, non-transformed prostate epithelial cells (PrEC LH) presented a stiffer and rupture resilient property compared to transformed prostate cancer cells (PC-3) which presented a softer and vulnerable property. Besides, the alteration of shape of the aspirated membrane directly affected the stress distribution over the membrane and as a result, provoked membrane failure. Multiple pieces of research have shown a higher stiffness of healthy cells compared to cancer cells including one of the previous studies done by our group which have also found that cancer cell tends to become stiffer after exposing to fluid shear stress. The discovery of this cellular behavior and novel numerical quantification method of cell failure could advance the study of cancer cell membrane failure, cellular matrix structure, response to mechanical loadings and potentially foundation in developing new treatment for cancer other than destructive chemical treatment.

Grouping students with in the school setting has long been a concern to all those associated with the educative process. Much investigation has been devoted to the position of level of aspiration as influential motive forces for educational, occupational, and social achievement. Many avenues of grouping have been investigated and some very thoroughly. However, research concerning grouping in relation to level of aspiration in the school setting appears to be extremely limited. This study is designed to further investigate this issue. It might be said that this study consists of essentially two phases: (1) the development of instruments for measuring classroom aspiration, social aspiration, and educational aspiration; and (2) the determination of level of aspiration relationships which exist between junior high school boys grouped on the basis of ability and those randomly assigned to a classroom.

<p>This Thesis explores the development of word-initial s+plosive consonant clusters in the speech of Swedish children between the ages of 1;6 and 4;6. Development in the word-initial consonant clusters is viewed as being determined by 1) the children’s ability to articulate the target sequence of consonants, 2) the level of understanding of which acoustic features in the adult model production are significant for the signalling of the intended distinction, and 3) the children’s ability to apply established production patterns only to productions where the acquired feature agrees with the adult target, to achieve a contrast between rival output forms. This Thesis employs a method where output forms are contrasted with attempted productions of potential homonym target words. Thus, development is quantified as an increase in the manifestations of phonetic features where it agrees with the adult norm, coupled by a decrease in the same feature in output forms where it is inappropriate according to the specifications of the phonological system of the ambient language. Acoustic investigations of cues of voicing, aspiration, place of articulation and syllable onset complexity, and auditory investigations of place, manner and syllable onset complexity were conducted. The Thesis has four outcomes. One, a description of the perceptual quality of the productions in terms of place, manner, voicing and syllable onset complexity is presented. Two, a developmental sequence of stable acquisition of these features is proposed; manner is shown to be acquired first, followed by syllable onset complexity and place of articulation. Evidence is provided that the voiced/aspirated distinction is still being acquired at the end of the investigated age period. Three, the developmental use of acoustic cues of place and voicing are described. Voice Onset Time and Spectral Skewness are shown to be used by children in order to increase the likeness to the adult target in terms of voicing and place of articulation. Aspiration Amplitude is shown to be used as an auxiliary cue to Voice Onset Time. The place cues Spectral Tilt Change, F2, Spectral Mean and Spectral Variance were shown to be used in order to refine already produced consonants rather than approach the adult target model. Four, the Thesis provides evidence of periods of confusions in the output of children. With the reductions of these patterns of confusion, evidence is provided of children’s re-organisation of their internal representation of the consonant to be produced.</p> / <p>Denna avhandling undersöker utvecklingen av ordinitiala konsonantkluster av formen s+klusil i talet hos svenska barn mellan åldrarna 1;6 och 4;6. Utvecklingen av de ordinitiala klustren betraktas som bestämd av 1) barnets förmåga att artikulera den konsonantsekvens som utgör målet, 2) barnets förståelse för vilka akustiska särdrag i den vuxna målproduktionen som är signifikanta för att signalera en viss distinktion och 3) barnets förmåga att tillämpa ett etablerat produktionsmönster endast på de produktioner där det tillägnade draget överensstämmer med den vuxna målproduktionen, så att en kontrast uppnås mellan konkurrerande utformer. Avhandlingen tillämpar en metod där producerade utformer kontrasteras med produktioner av målord som utgör potentiella homonymer till dessa. Utvecklingen kan då kvantifieras som en ökning av antalet förekomster av ett fonetiskt drag som överensstämmer med den vuxna normen för den relevanta kontexten, kopplad till en minskning av antalet förekomster av samma drag i kontext där draget är inkorrekt givet det fonologiska systemet i det språk som tillägnas. De drag som undersöktes var de akustiska korrelaten till stämbandston, aspiration, artikulationsställe och komplexitet i stavelseansatsen, och vidare de auditiva korrelaten till artikulationsställe, artikulationssätt och komplexitet i stavelseansatsen. Fyra resultat redovisas. För det första presenteras en beskrivning av den perceptuella kvaliteten hos barnens produktioner i termer av artikulationsställe, artikulationssätt och komplexitet. För det andra föreslås en utvecklingssekvens för stabilt tillägnande av dessa drag: artikulationssätt tillägnas först, följt av komplexitet hos stavelseansatsen och artikulationsställe. Sist tillägnas distinktionen mellan tonande och aspirerad klusil, där data visar att draget inte tillägnats till fullo vid slutet av det undersökta åldersintervallet. För det tredje ger avhandlingen en beskrivning av hur barnen utvecklar sitt bruk av akustiska korrelat till artikulationsställe och ton. Voice Onset Time och snedhet i spektrum används för att närma sig det vuxna målet gällande aspiration och artikulationsställe. Aspirationsamplitud används som ett hjälpkorrelat till VOT vad gäller fonetisk aspiration. Andra korrelat för artikulationsställe, som förändring i spektral lutning, F2, spektralt medelvärde och spektral varians, används för att förfina de egna produktionerna snarare än för att få produktionen att närma sig det vuxna målet. För det fjärde ges i avhandlingen evidens för perioder då barnens produktion uppvisar förväxlingar vad avser distributionen hos vissa fonetiska drag. Minskade förekomster av sådana förväxlingar visar på en omstrukturering av barnens underliggande representation för den konsonant som ska produceras.</p>

<p>Much language planning and policy in recent years in South Africa tends to overlook linguistic situations and practices, and focuses on notions of top-down language policy and implementation. This does not fit easily with the current multilingualism dynamics of late post-modern societies, which are increasingly characterized by a culture of consumerism and politics of aspiration. Taking its point of departure from a critical analysis of linguistic practices, in the form of visual literacies (billboards) in a township in South Africa, this thesis aims to draw forth alternative approaches that focus on the notion of sociolinguistic consumption, politics of aspiration and stylization of self, as a means of addressing the linguistic situation, and highlighting implications for language planning and multilingualism.</p>

This Thesis explores the development of word-initial s+plosive consonant clusters in the speech of Swedish children between the ages of 1;6 and 4;6. Development in the word-initial consonant clusters is viewed as being determined by 1) the children’s ability to articulate the target sequence of consonants, 2) the level of understanding of which acoustic features in the adult model production are significant for the signalling of the intended distinction, and 3) the children’s ability to apply established production patterns only to productions where the acquired feature agrees with the adult target, to achieve a contrast between rival output forms. This Thesis employs a method where output forms are contrasted with attempted productions of potential homonym target words. Thus, development is quantified as an increase in the manifestations of phonetic features where it agrees with the adult norm, coupled by a decrease in the same feature in output forms where it is inappropriate according to the specifications of the phonological system of the ambient language. Acoustic investigations of cues of voicing, aspiration, place of articulation and syllable onset complexity, and auditory investigations of place, manner and syllable onset complexity were conducted. The Thesis has four outcomes. One, a description of the perceptual quality of the productions in terms of place, manner, voicing and syllable onset complexity is presented. Two, a developmental sequence of stable acquisition of these features is proposed; manner is shown to be acquired first, followed by syllable onset complexity and place of articulation. Evidence is provided that the voiced/aspirated distinction is still being acquired at the end of the investigated age period. Three, the developmental use of acoustic cues of place and voicing are described. Voice Onset Time and Spectral Skewness are shown to be used by children in order to increase the likeness to the adult target in terms of voicing and place of articulation. Aspiration Amplitude is shown to be used as an auxiliary cue to Voice Onset Time. The place cues Spectral Tilt Change, F2, Spectral Mean and Spectral Variance were shown to be used in order to refine already produced consonants rather than approach the adult target model. Four, the Thesis provides evidence of periods of confusions in the output of children. With the reductions of these patterns of confusion, evidence is provided of children’s re-organisation of their internal representation of the consonant to be produced. / Denna avhandling undersöker utvecklingen av ordinitiala konsonantkluster av formen s+klusil i talet hos svenska barn mellan åldrarna 1;6 och 4;6. Utvecklingen av de ordinitiala klustren betraktas som bestämd av 1) barnets förmåga att artikulera den konsonantsekvens som utgör målet, 2) barnets förståelse för vilka akustiska särdrag i den vuxna målproduktionen som är signifikanta för att signalera en viss distinktion och 3) barnets förmåga att tillämpa ett etablerat produktionsmönster endast på de produktioner där det tillägnade draget överensstämmer med den vuxna målproduktionen, så att en kontrast uppnås mellan konkurrerande utformer. Avhandlingen tillämpar en metod där producerade utformer kontrasteras med produktioner av målord som utgör potentiella homonymer till dessa. Utvecklingen kan då kvantifieras som en ökning av antalet förekomster av ett fonetiskt drag som överensstämmer med den vuxna normen för den relevanta kontexten, kopplad till en minskning av antalet förekomster av samma drag i kontext där draget är inkorrekt givet det fonologiska systemet i det språk som tillägnas. De drag som undersöktes var de akustiska korrelaten till stämbandston, aspiration, artikulationsställe och komplexitet i stavelseansatsen, och vidare de auditiva korrelaten till artikulationsställe, artikulationssätt och komplexitet i stavelseansatsen. Fyra resultat redovisas. För det första presenteras en beskrivning av den perceptuella kvaliteten hos barnens produktioner i termer av artikulationsställe, artikulationssätt och komplexitet. För det andra föreslås en utvecklingssekvens för stabilt tillägnande av dessa drag: artikulationssätt tillägnas först, följt av komplexitet hos stavelseansatsen och artikulationsställe. Sist tillägnas distinktionen mellan tonande och aspirerad klusil, där data visar att draget inte tillägnats till fullo vid slutet av det undersökta åldersintervallet. För det tredje ger avhandlingen en beskrivning av hur barnen utvecklar sitt bruk av akustiska korrelat till artikulationsställe och ton. Voice Onset Time och snedhet i spektrum används för att närma sig det vuxna målet gällande aspiration och artikulationsställe. Aspirationsamplitud används som ett hjälpkorrelat till VOT vad gäller fonetisk aspiration. Andra korrelat för artikulationsställe, som förändring i spektral lutning, F2, spektralt medelvärde och spektral varians, används för att förfina de egna produktionerna snarare än för att få produktionen att närma sig det vuxna målet. För det fjärde ges i avhandlingen evidens för perioder då barnens produktion uppvisar förväxlingar vad avser distributionen hos vissa fonetiska drag. Minskade förekomster av sådana förväxlingar visar på en omstrukturering av barnens underliggande representation för den konsonant som ska produceras.

The first chapter is based on a paper with Jin Li in fair division. It was recently discovered that on the domain of Leontief preferences, Hurwicz (1972)'s classic impossibility result does not hold; that is, one can find efficient, strategy-proof and individually rational rules to divide resources among agents. Here we consider the problem of dividing l divisible goods among n agents with the generalized Leontief preferences. We propose and characterize the class of generalized egalitarian rules which satisfy efficiency, group strategy-proofness, anonymity, resource monotonicity, population monotonicity, envy-freeness and consistency. On the Leontief domain, our rules generalize the egalitarian-equivalent rules with reference bundles. We also extend our rules to agent-specific and endowment-specific egalitarian rules. The former is a larger class of rules satisfying all the previous properties except anonymity and envy-freeness. The latter is a class of efficient, group strategy-proof, anonymous and individually rational rules when the resources are assumed to be privately owned. The second and third chapters are based on two working papers of mine in decision making under uncertainty. In the second chapter, I study the wealth effect under uncertainty --- how the wealth level impacts a decision maker's degree of uncertainty aversion. I axiomatize a class of preferences displaying decreasing absolute uncertainty aversion, which allows a decision maker to be more willing to take uncertainty-bearing behavior when he becomes wealthier. Three equivalent preference representations are obtained. The first is a variation on the constraint criterion of Hansen and Sargent (2001). The other two respectively generalize Gilboa and Schmeidler (1989)'s maxmin criterion and Maccheroni, Marinacci and Rustichini (2006)'s variational representation. This class, when restricted to preferences exhibiting constant absolute uncertainty aversion, is exactly Maccheroni, Marinacci and Rustichini (2006)'s ariational preferences. Thus, the results further enable us to establish relationships among the representations for several important classes within variational preferences. The three representations provide different decision rules to rationalize the same class of preferences. The three decision rules correspond to three ways which are proposed in the literature to identify a decision maker's perception about uncertainty and his attitude toward uncertainty. However, I give examples to show that these identifications conflict with each other. It means that there is much freedom in eliciting two unobservable and subjective factors, one's perception about and attitude toward uncertainty, from only his choice behavior. This exactly motivates the work in Chapter 3. In the third chapter, I introduce confidence orders in addition to preference orders. Axioms are imposed on both orders to reveal a decision maker's perception about uncertainty and to characterize the following decision rule. A decision maker evaluates an act based on his aspiration and his confidence in this aspiration. Each act corresponds to a trade-off line between the two criteria: The more he aspires, the less his confidence in achieving the aspiration level. The decision maker ranks an act by the optimal combination of aspiration and confidence on its trade-off line according to an aggregating preference of his over the two-criterion plane. The aggregating preference indicates his uncertainty attitude, while his perception about uncertainty is summarized by a generalized second-order belief over the prior space, and this belief is revealed by his confidence order.

The thesis compared the likelihood of taking risks in dyads and individuals in varying situations. Patterns of risky decision making were examined in the standard risky choice task and a novel risk management task. The relative successes of two theories of risky decision making were assessed: Prospect Theory emphasizes perceptual and psychophysical processes, whereas Security-Potential/Aspiration Level Theory emphasizes dispositional and motivational processes. The thesis also examined dyads’ decision behavior in light of competing social influence perspectives regarding risky versus cautious shifts and group polarization. Participants, as individuals or as part of a dyad, made decisions in 23 trials about hypothetical two-outcome monetary gambles in one of two different tasks. Risky choice involved making choices between two given 50-50 lotteries which varied in riskiness (i.e., outcome variability), whereas risk management required actively manipulating an existing 50-50 risk by changing outcome values. The 23 trials were equivalent across tasks. Dyad participants communicated via an instant messenger program, while viewing the same lotteries on different computers. Data on risk preferences across gain and loss domains were analyzed using a mixed factorial ANOVA design. Consistent with Prospect Theory value function predictions, the risky choice task led to risk averse preferences for gains and risk seeking preferences for losses, though risk seeking was weak. Consistent with SP/A theory predictions, the risk management task led to overall risk averse preferences, with movement toward risk taking for gains. In addition, there was some evidence of social influences in that dyads tended to be more conservative than individuals in their decision behavior when dealing with undesirable outcomes. Thus, a cautious shift was observed, but only for lotteries involving guaranteed losses. This could not be explained by group polarization.  Each of the theories received some support, but none of them could explain all of the findings. Recommendations were made to give greater attention to defining and measuring risk attitudes and dispositions, and to continue exploring differences in decision situations and social settings to obtain a more comprehensive understanding of risky decision making processes. Findings here suggest the need for an overarching theory that can account for a wide variety of influences. A dual processes approach was recommended as one promising avenue. Social and situational influences may prove an essential part of understanding risky decision making in real life contexts.

<p>Much language planning and policy in recent years in South Africa tends to overlook linguistic situations and practices, and focuses on notions of top-down language policy and implementation. This does not fit easily with the current multilingualism dynamics of late post-modern societies, which are increasingly characterized by a culture of consumerism and politics of aspiration. Taking its point of departure from a critical analysis of linguistic practices, in the form of visual literacies (billboards) in a township in South Africa, this thesis aims to draw forth alternative approaches that focus on the notion of sociolinguistic consumption, politics of aspiration and stylization of self, as a means of addressing the linguistic situation, and highlighting implications for language planning and multilingualism.</p>

Pour ce travail de thèse, nous avons réalisé cinq études originales en utilisant trois technologies d'imageries cardiovasculaires non-invasives.-Nous avons démontré, à partir d'une étude ex-vivo sur des artères coronaires humaines, que le scanner64 détecteurs ne permettait pas de caractériser précisément les différents composants des plaques. Ladistinction des plaques fibreuses et des plaques lipidiques est en effet impossible. Par ailleurs, notretravail a montré que l'IVUS ne devait pas servir d'imagerie de référence lors des études sur la plaque carcet examen présente lui aussi de nombreuses imprécisions.-Notre travail sur la thrombo-aspiration rapporte un effet très significatif de l'extraction effective dethrombus lors des thrombo-aspirations à la phase aiguë des STEMI, avec une réduction de la taille du no-reflow et de l'infarctus, évaluées en IRM ; une thrombo-aspiration positive représentant par ailleurs dansnotre travail, un critère indépendamment lié à la taille finale de l'infarctus. L'extraction effective dethrombus pourrait être considéré, en salle de cathétérisme, comme un critère de jugement de l'efficacitéde la thrombo-aspiration.-Notre étude sur les syndomes coronaires à coronaires angiographiquement normales a confirmé l'intérêtde l'IRM dans le bilan étiologique de cette présentation clinique, permettant un diagnostic étiologiquedans 2/3 des cas. Par ailleurs, nous avons observé une excellente évolution pour le tiers des patients chezqui l'IRM ne décèle pas d'anomalie myocardique. Des études d'une plus grande envergure serontnécessaires afin de confirmer nos résultats.-A partir d'IRM cardiaque réalisées chez des patients ayant présenté un premier épisode de STEMI, nousavons pu déterminer une valuer seuil de troponine prédictive de la survenue d'un no-reflow.-Enfin, à partir d'analyses en Speckle Tracking, nous avons mis en évidence une dysfonction systolique VD,objectivée par une altération des valeurs de Strain longitudinal VD, chez les patients présentant une EPgrave ou de gravité intermédiaire, comparativement à un groupe de patients avec une EP non grave. / In this doctoral thesis, we report on five original studies that use three différent non-invasive cardiovascular imaging techniques:- In an ex vivo study of human coronary arteries, we show that 64-slice computed tomography (CT) scan isnot capable of distinguishing between différent components of plaques. Indeed, it is impossible todifferentiate between fibrous and lipid plaques. Our study also showed that intravascular ultrasound(IVUS) should not be used as thé référence method in studies of plaque composition, since this techniquealso suffers from numerous limitations.- Our study of thé efficacy of thrombo-aspiration showed a significant benefit with effective extraction ofthrombus during thrombo-aspiration at thé acute phase of ST élévation myocardial infarction (STEMI),notably with a réduction of thé extent of no-reflow and of infarct size as evaluated by magnetic résonanceimaging (MRI). Productive thrombo-aspiration was shown in our study to be an independent predictor offinal infarct size. Effective extraction of thrombotic material could be considered in thé cathlab as acriterion for evaluating thé success of thé thrombo-aspiration procédure.- Our study of acute coronary syndromes with normal coronary arteries confirmed thé utility of MRI inestablishing thé etiology of this clinical présentation, and made it possible to establish an etiologicaldiagnosis in two-thirds of patients. We also observed excellent outcomes in thé third of patients in whomMRI did not find any myocardial anomalies. Larger studies are warranted to confirm thèse findings.- Based on cardiac MRI performed in patients presenting a first épisode of STEMI, we established athreshold value of troponin that predicts thé occurrence of no-reflow.- Lastly, using speckle-tracking analysis, we demonstrated impaired systolic right ventricular function inpatients with intermediate to high risk pulmonary embolism (PE), evaluated by altérations in longitudinalstrain values at thé level of thé right ventricle, compared to a control group of patients with low risk PE.