(when) Do Consumers Prefer Uncertainty? Consumers\u27 Reactions To Uncertain Advice And Uncertain Promotions

Research has shown that, although uncertainty is often disliked, consumers sometimes seem to prefer uncertainty to certainty. The goal of this dissertation is to further understand the circumstances under which consumers prefer, rather than dislike, uncertainty across different domains. In Chapter 1, we investigate preferences for uncertainty in the domain of advice giving. There is a widespread belief that advisees prefer, and thus reward, advisors who offer certainty, even for events that are inherently uncertain. In contrast, we find that consumers do not dislike, and sometimes prefer, uncertain advice. Specifically, they do not dislike advisors who express uncertainty by providing ranges of outcomes, giving numerical probabilities, or saying one event is “more likely” than another. In addition, when faced with an explicit choice, people are more likely to choose an advisor who provides uncertain advice over certain advice. In Chapter 2, we extend our investigation to preferences for uncertainty in the domain of price promotions. We test why and when consumers may prefer an uncertain price promotion, such as a 10% chance to get a product for free, to an equivalent sure discount. We find that uncertain price promotions are relatively more effective only when the equivalent sure discounts feel small. Specifically, we find that uncertain promotions are relatively more effective when the sure discounts are actually smaller, when the sure discounts are made to feel smaller by presenting them alongside a larger discount, and when the sure discounts are made to feel smaller by framing them as a percentage-discount rather than a dollar amount. This suggests that people’s preferences for uncertainty are more strongly tethered to their perceptions of the size of the sure outcome than they are to their perceptions of the probability of getting the uncertain reward. Taken together, this dissertation challenges long-held beliefs about how uncertainty affects consumers’ judgments and decisions and highlights the circumstances under which consumers prefer, rather than dislike, uncertainty

Gravitational wave asteroseismology with fast rotating neutron stars

We investigate damping and growth times of the f-mode for rapidly rotating stars and a variety of different polytropic equations of state in the Cowling approximation. We discuss the differences in the eigenfunctions of co- and counterrotating modes and compute the damping times of the f-mode for several EoS and all rotation rates up to the Kepler-limit. This is the first study of the damping/growth time of this type of oscillations for fast rotating neutron stars in a general relativistic framework. We use these frequencies and damping/growth times to create robust empirical formulae which can be used for gravitational wave asteroseismology. The estimation of the damping/growth time is based on the quadrupole formula and our results agree very well with Newtonian ones in the appropriate limit.Comment: 15 pages, 8 figures, version accepted for publication in PhysRev

Social information and personal interests modulate neural activity during economic decision-making

In the present study we employed electrophysiological recordings to investigate the levels of processing at which positive and negative descriptions of other people bias social decision-making in a game in which participants accepted or rejected economic offers. Besides social information, we manipulated the fairness of the assets distribution, whether offers were advantageous or not for the participant and the uncertainty of the game context. Results show that a negative description of the interaction partner enhanced the medial frontal negativity (MFN) in an additive manner with fairness evaluations. The description of the partner interacted with personal benefit considerations, showing that this positive or negative information only biased the evaluation of offers when they did not favor the participant. P300 amplitudes were enhanced by advantageous offers, suggesting their heightened motivational significance at later stages of processing. Throughout all stages, neural activity was enhanced with certainty about the personal assignments of the split. These results provide new evidence on the importance of interpersonal information and considerations of self-interests relative to others in decision-making situations.Financial support to this research came from the Spanish Ministry of Science and Innovation through a “Ramón y Cajal” research fellowship (RYC-2008-03008) and grant PSI2010-16421 to María Ruz, and also from the European Commission through a “Leonardo da Vinci” fellowship (DE/10/LLP-LdV/PLM/282611) to Anna Moser

Oscillations and instabilities of fast and differentially rotating relativistic stars

We study non-axisymmetric oscillations of rapidly and differentially rotating relativistic stars in the Cowling approximation. Our equilibrium models are sequences of relativistic polytropes, where the differential rotation is described by the relativistic $j$-constant law. We show that a small degree of differential rotation raises the critical rotation value for which the quadrupolar f-mode becomes prone to the CFS instability, while the critical value of $T/|W|$ at the mass-shedding limit is raised even more. For softer equations of state these effects are even more pronounced. When increasing differential rotation further to a high degree, the neutral point of the CFS instability first reaches a local maximum and is lowered afterwards. For stars with a rather high compactness we find that for a high degree of differential rotation the absolute value of the critical $T/|W|$ is below the corresponding value for rigid rotation. We conclude that the parameter space where the CFS instability is able to drive the neutron star unstable is increased for a small degree of differential rotation and for a large degree at least in stars with a higher compactness.Comment: 16 pages, 11 figures; paper accepted for publication in Phys. Rev. D (81.084019

Natürliche Regeneration von Fahrspuren im Wald: Bodenphysikalische und bodenbiologische Betrachtungen

In dieser Studie wurde die natürliche Regeneration von Bodenverdichtung im Wald auf unterschiedlich alten Rückegassen (10-40 Jahre nach der letzten Befahrung) in zwei verschiedenen Regionen anhand von bodenbiologischen und bodenphysikalischen Parametern untersucht. In der Region Göttingen konnte auf Standorten mit hoher biologischen Aktivität und hohen Tongehalten 10-20 Jahre nach der letzten Befahrung eine Regeneration festgestellt werden. Im Gegensatz dazu war die Regeneration in der Region Heide auf pleistozänen verlehmten Sanden auch nach 40 Jahren noch nicht komplett abgeschlossen: Der Gasdiffusionskoeffizient war 40 Jahre nach der letzten Befahrung auf der Rückegasse signifikant geringer als im unbefahrenen Bereich

Modèles probabilistes de feux de forêt sur des graphes infinis

Cette thèse concerne l'étude de modèles de feux de forêt d'un point de vue probabiliste. Les modèles que nous avons étudiés ont été introduits dans le cadre de l'étude des systèmes critiques auto-organisés à la fin des années 80. Il s'agit de systèmes de particules, les arbres, définis sur un graphe connecté. Leur évolution est régie par deux familles de processus de Poisson, l'une pour la croissance des arbres, l'autre pour leur disparition via l'action de la foudre. L'influence de la foudre est caractérisée par un paramètre lambda > 0. Ces modèles ont été beaucoup étudiés sur Z. Par contre sur des graphes infinis plus généraux, seules son existence et son unicité ont été montrées jusqu'à présent. Dans cette thèse, nous avons étudié ces modèles sur Zd pour d > 2 et sur les arbres binaires, dans deux directions. La première concerne l'existence de mesures invariantes. La deuxième concerne l'étude de ce modèle lorsque le paramètre lambda tend vers 0. Dans la première partie, nous montrerons que pour tous les paramètres lambda > 0, les processus de feux de forêt sur Zd pour d > 2 possèdent au moins une mesure invariante. Les processus de feux de forêt sont des processus de Markov non Feller, donc on ne peut pas appliquer les théorèmes usuels de l'étude des systèmes de particules. De plus, la géométrie de Zd ne permet pas d'utiliser les mêmes arguments que dans le cas de Z. Nous utiliserons des outils développés lors de l'étude de ces modèles sur Zd. Dans une seconde partie, nous nous consacrerons à la problématique de l'existence d'un processus limite lorsque lambda tend vers 0, sur les arbres binaires. Dans un premier temps, nous étudierons un modèle sans feux pour mieux comprendre comment grossissent les composantes connexes d'arbres. En se plaçant dans une nouvelle échelle de temps et d'espace, nous montrerons la convergence en loi de la taille d'un ensemble de sites construit à partir d'une boule de rayon n et des composantes connexes qui l'intersectent, au bout d'un temps t(n) > 0. Dans un deuxième temps, nous rajouterons l'action de feux, en définissant un modèle différent du modèle initial. Dans ce modèle modifié, les composantes connexes autres que celle de l'origine suivront une loi stationnaire à laquelle on s'attend à la limite, et non la dynamique du modèle de feux de forêt initial. Pour ce modèle, nous montrerons la convergence en loi de la taille renormalisée de la composante connexe de l'origine au moment où elle brûle pour la première fois.This work is concerned with a probabilistic study of forest-fire models. The models studied here were introduced in the context of self-organized criticality at the end of the eighties. These models are systems of particles, the trees, defined on connected graphs. Their evolution is governed by two families of Poisson processes, one for the growth of trees, the other one for the ignition of trees by lightning. The influence of lightning is characterized by a parameter lambda > 0. These models were widely studied on Z. However, only the existence and uniqueness of more general infinitevolume forest-fire processes have been proven yet. In this thesis, we studied forest-fire models on Zd for d > 2 and on binary trees, in two directions. The first one is concerned with the existence of stationary measures. The second one is concerned with the study of these processes when the parameter lambda tends to zero. In the first part, we will show the existence of at least one stationary measure for forest-fire processes on Zd, d > 2, for all parameters lambda > 0. The forest-fire processes are Markov processes but not Feller processes, so the usual arguments cannot be used here. Moreover, the geometry of Zd does not allow using the same arguments as for Z. Tools developed while studying these processes on Zd will be used here. In the second part, we will study the behavior of the forest-fire processes on binary trees when the parameter lambda tends to zero. We will begin with the study of a model without any fires, in order to understand better how the clusters of trees grow. We will show a convergence in law of the number of sites of a set construct from a ball of radius and the intersecting clusters, after a time tn > 0, for processes rescaled in space and time. Then, we will add fires and define a modified forest-fire model. In this new model, apart from the cluster of the origin, the clusters evolve under a stationary measure which we expect at the limit in lambda, and not under the dynamic of the initial forest-fire model. For this model, we will show a convergence in law of the rescaled size of the cluster of the origin when it burns for the first time

CCTα and CCTδ Chaperonin Subunits Are Essential and Required for Cilia Assembly and Maintenance in Tetrahymena

Background - The eukaryotic cytosolic chaperonin CCT is a hetero-oligomeric complex formed by two rings connected back-to-back, each composed of eight distinct subunits (CCTalpha to CCTzeta). CCT complex mediates the folding, of a wide range of newly synthesised proteins including tubulin (alpha, beta and gamma) and actin, as quantitatively major substrates. Methodology/Principal findings - We disrupted the genes encoding CCTalpha and CCTdelta subunits in the ciliate Tetrahymena. Cells lacking the zygotic expression of either CCTalpha or CCTdelta showed a loss of cell body microtubules, failed to assemble new cilia and died within 2 cell cycles. We also show that loss of CCT subunit activity leads to axoneme shortening and splaying of tips of axonemal microtubules. An epitope-tagged CCTalpha rescued the gene knockout phenotype and localized primarily to the tips of cilia. A mutation in CCTalpha, G346E, at a residue also present in the related protein implicated in the Bardet Biedel Syndrome, BBS6, also caused defects in cilia and impaired CCTalpha localization in cilia. Conclusions/Significance - Our results demonstrate that the CCT subunits are essential and required for ciliary assembly and maintenance of axoneme structure, especially at the tips of cilia