A critical function of perception is the organization of temporally spaced input. This is accomplished through grouping, a process by which within-group elements are integrated with one another to form a cohesive unit. Grouping also requires boundaries to set off within-group elements from unrelated stimuli. In the temporal domain, grouping may be accomplished through use of an implicit working memory system that connects temporally spaced information. Temporal group boundaries may be created by reductions in the default integrative processes of this memory system. The present experiments probed integration strength by embedding priming tasks within temporal groups (i.e., events). Because priming also draws upon implicit working memory, priming strength should reflect the strength of integration. If modulation of temporal integration is responsible for grouping, this should be manifested as a reduction of priming across boundaries. Irrelevant feature priming tasks were used to assess integration strength. Participants responded to one of two independently varying object features. In this form of priming, change consistency of relevant and irrelevant features produces faster reaction times, resulting in a crossed interaction. This interaction served as a meter for the strength of temporal integration. The experiments included a variety of temporal grouping manipulations. Experiments involving rhythmic groups, spatial shifts, rotations, pitch, and timbre, as well as higher-level conceptual shifts, demonstrated reduced priming in across-boundary conditions. Both visual and auditory events were used, and experiments demonstrated that viewers’ interpretation of a scene contributed to the observed effects. Temporal integration does appear to be reduced at certain event boundaries, suggesting that this may be the general manner in which temporal grouping is accomplished. Motion change, a boundary from event segmentation research, did not reduce priming, indicating that the process presently under study differs from that studied using explicit segmentation procedures. The reduction of integration may correspond to a subjective, amodal experience of separation. The present technique may therefore offer an objective, implicit method to assess this sense of separation. Using this method, it is possible to reliably determine when people are experiencing temporal group boundaries even when they are not deliberately attending to them. / text

Object perception is necessary to our understanding of the visual world, yet its neural mechanism remains poorly understood. The goal of this dissertation is to shed light on this mechanism. Current computational models of object perception suggest that regions on opposite sides of a shared border compete, with the winner perceived as the shaped object and the loser as its locally shapeless background (or ground). Recent behavioral work indicates that the result of this competition is suppression of the ground at the level of object shape--a finding not predicted by models. Here, I present three studies that extend this previous research on ground suppression as a mechanism by which object perception is accomplished. I first show that the amount of suppression applied to the ground depends on the amount of competition for object status (Salvagio, Cacciamani, & Peterson, 2012). I then provide the first neural evidence of ground suppression from shape-level competition at both high and low levels of the visual hierarchy, with the latter arising from top-down feedback (Cacciamani, Scalf, & Peterson, submitted). Finally, I show that semantic information pertaining to the ground is accessed prior to the assignment of object status, but unlike shape information, is not suppressed (Cacciamani, Mojica, Sanguinetti, & Peterson, 2014). Together, the three studies that comprise this dissertation demonstrate that ground suppression arising from shape-level competition underlies object perception. This research contradicts traditional theories stating that objects are processed unidirectionally through the visual system in a single feedforward pass; instead, it supports theories of object perception entailing dynamical feedforward and feedback processes.

During the production of language, speakers tend to use the same structural patterns from one utterance to the next if it is possible to do so. For example, if a speaker uses a passive or dative construction, he/she is relatively more likely to use the same construction again in the next utterance (e.g., Bock, 1986; Bock & Loebell, 1990; Hartsuiker & Kolk, 1998): the sentence structure "persists".The current study investigates syntactic persistence in first and second language speakers of English and Korean using within-language primes (Experiments 1A, 1B, and 2) and across-language primes (Experiment 3). The target structures were transitive alternate structures (active and passive) and dative alternate structures (double object dative/DAT-ACC dative and prepositional dative/ACC-DAT dative). The experimental paradigm involved repetition of an auditory stimulus, followed by picture description. Overall, syntactic priming effects were found, although various magnitudes were observed as a function of structure; strong effects were found for "shared" syntactic constructions across languages (e.g., active vs. passive) and weak priming effects were found for syntactic constructions not shared (e.g., double object dative vs. prepositional dative) between English and Korean. Other asymmetrical priming effects were observed, reflecting differences between Korean and English such that reliable priming effects were found from L1 to L2, but not from L2 to L1 for Korean-as-L2 speakers (English-as-L1) These patterns of asymmetrical priming imply that cross-linguistic differences might interfere with syntactic persistence in production process unless speakers are highly advanced proficient bilinguals. Also, the present study showed that syntactic priming appears to be sensitive to the order of case-marked phrases in the cross-language priming condition. This finding indicates that the order of case-marked arguments is involved in syntactic repetition. It shed lights on further universal accounts of syntactic priming.

Biologically active 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) binds the vitamin D receptor (VDR) to exert its effect on target cells. VDR expression is found in a number of immune cells including professional antigen-presenting cells such as dendritic cells. It has been found that the actions of 1,25-(OH)2D3 on the immune system are mainly immunosuppressive. The cross-presentation pathway allows for exogenously derived antigens to be presented by pAPCs on MHC-I molecules to CD8+ T cells. CD8+ T cell activation results in the expansion of epitope-specific T cell populations that confer host protection. These epitopes can be organized into an immunodominance hierarchy. Previous work demonstrated that introducing LCMV-NP via the cross-priming pathway significantly alters the immunodominance hierarchy of a subsequent LCMV infection. Building upon these observations, our study assessed the effects of LCMV-NP cross priming in the presence of a single dose of 1,25-(OH)2D3. Treatment with 1,25-(OH)2D3 was found to have biological effects in our model system. In vitro pAPCs were demonstrated to up-regulate IL-10 and CYP24A1 mRNA, in addition to the transactivation of cellular VDR, as demonstrated by a relocalization to the nuclear region. Mice treated with 1,25-(OH)2D3 were found to produce up-regulated IL-10 and CYP24A1 transcripts. Expression of VDR was increased at both the transcript and protein level. Our results demonstrate that a single dose of 1,25-(OH)2D3 does not affect the cross-priming pathway in this system. Treatment with 1,25-(OH)2D3 did not influence the ability of differentiated pAPCs to phagocytose or cross-present exogenous antigen to epitope-specific CD8+ T cells. Furthermore, 1,25-(OH)2D3 did not alter cross-priming or the establishment of the LCMV immunodominance hierarchy in vivo. By confirming that 1,25-(OH)2D3 does not suppress cross-priming in our model, our study helps to expand the understanding of the immunomodulatory role of exogenous 1,25-(OH)2D3 on the outcome of virus infection. Collectively, our data supports the observation that the role of 1,25-(OH)2D3 in the immune system is not always associated with suppressive effects. / Thesis (Master, Microbiology & Immunology) -- Queen's University, 2011-08-29 14:53:18.766

L'immunité des invertébrés a longtemps été définie comme reposant sur une immunité innée simple basée sur une reconnaissance peu spécifique. Cependant depuis 20 ans les preuves que l'immunité des invertébrés présente de la spécificité se multiplient. De la même façon un phénomène de mémoire immunitaire nommé priming immunitaire a également été décrit chez ces derniers. Dans le cadre de ce travail de thèse j'ai pu étudier sous différents aspect le priming immunitaire chez Biomphalaria glabrata, un mollusque d'eau douce, face à son parasite naturel Schistosoma mansoni. Dans un premier temps nous avons pu démontrer que le priming immunitaire était spécifique du génotype du premier parasite entrant dans le mollusque. De plus, il apparaît que la succession des différents stades de développement du parasite stimule l'immunité séquentiellement afin d'engendrer une protection totale. Enfin nous nous sommes intéressés aux mécanismes sous jacents à ce priming immunitaire en focalisant notre attention sur les facteurs humoraux impliqués dans cette réponse de priming immunitaire. Nous avons observé différentes molécules pouvant être associées à la réponse de priming tant dans la spécificité de reconnaissance que dans la phase effectrice de la réponse immunitaire.

Racism persists individually and institutionally in the U.S. and race-based comedy prevails in media, accepted by diverse audiences as jokes. Media priming and Social Identity Theory theoretically ground this two-part experimental study that examines Latino participants' judgments of in-group (Latino) and out-group (White) alleged offenders in judicial cases after being primed with race-based stereotype comedy performed by an in-group (Latino) or out-group (White) comedian. First, participants read race-based stereotype comedy segments and evaluated them on perceptions of the comedian, humor, enjoyment, and stereotypicality. Second, participants read two criminal judicial review cases for alleged offenders and provided guilt evaluations. Importantly, a distinction was made between high and low Latino identifier participants to determine whether racial identity salience might impact responses to in-group and/or out-group members in comedy and judicial contexts. The results reveal that the high Latino identifiers found the race-based comedy segments more stereotypical than did the low Latino identifiers. Latino participants rated the comedy higher on enjoyment when the comedian was perceived to be a Latino in-group member as opposed to a White out-group member. The high Latino identifiers rated the White alleged offender higher on guilt than the Latino alleged offender after being primed with race-based comedy. Simply projecting in-group or out-group racial identity of comedians and alleged offenders with name manipulations in the study influenced how participants responded to the comedy material, and persisted in guiding guilt judgments on alleged offenders in the judicial reviews based on participants' Latino identity salience. A Latino comedian's position as popular joke-teller in the media overrides in-group threat, despite invoking in-group stereotypes in humor. Even with greater enjoyment expressed for Latino comedians' performing stereotypical race-based material, the tendency to react more harshly against perceived out-group members as a defense strategy to maintain positive in-group salience remained in real-world judgments on alleged offenders. Despite the claim that light-hearted comedy is meant to be laughed at and not taken seriously, jokes that disparage racial groups as homogeneous, simplistic, and criminal impact subsequent responses to out-group members in a socially competitive attempt to maintain positive in-group identity, to the detriment of out-groups.

Evarcha culicivora, a species of jumping spider (Araneae: Salticidae from the Lake Victoria region of East Africa, has unusual prey-choice behaviour. It preferred prey is blood-carrying mosquitoes. It also has unusually complex mate-choice behaviour, with mutual mate choice being pronounced. This thesis is a study of E. culicivora’s prey-choice behaviour and mate-choice behaviour, as well as a study of processes underlying selective attention in this unusual species. E. culicivora uses olfaction in unique and often surprising ways. This includes identifying potential mates by odour alone, as well as choosing the odour of potential mates that have recently fed on blood-carrying mosquitoes. The odour of potential mates also primes both sexes for escalating conflict with potential rivals, as well as priming selective attention to the masked odour of specifically potential mates. Besides all this, the odour of blood-carrying mosquitoes primes E. culicivora to selectively attend to the masked odour of specifically this prey. Moreover, the appearance of blood-carrying mosquitoes and of potential mates primes E. culicivora to selectively attend to specifically the appearance of cryptic blood-carrying mosquitoes and cryptic potential mates, respectively. Vision and olfaction can even work together, with olfactory and visual cues from blood-carrying mosquitoes priming E. culicivora to selectively attend to the appearance and odour, respectively, of blood-carrying mosquitoes. Furthermore, E. culicivora has a poorly-understood relationship with two plant species, Lantana camara and Ricinus communis, and E. culicivora can identify these two plant species by odour alone. These plants may be relevant to this salticid as a nectar source by which it supplements its insect diet, but these plants may also be as sites at which E. culicivora males and females find potential mates, with E. culicivora’s interactions on these plants being especially exaggerated and complex.

La stimulation de cellules T naïves nécessite du déclenchement de la signalisation par l'intermédiaire du récepteur d'antigène de cellule T (TCR) ainsi que l'activation simultanée des récepteurs de co-stimulation. Toutefois, les cellules T CD8+ naïves peuvent proliférer de façon antigène-indépendants suite à la stimulation synergique par certaines cytokines homéostatiques (IL-7 ou IL-15) et inflammatoires (IL-6 ou IL-21). Ces cellules pré-stimulées prolifèrent même à des faibles concentrations d'antigènes ou en présence d’agonistes du TCR. Ceci leur permet de sécréter des cytokines effectrices, d'être plus spécifiques à leur antigène et d’avoir une activité cytolytique plus importante. Les mécanismes déclenchés par les cellules T CD8+ permettant une sensibilité accrue à l'antigène suite à la "pré-stimulation aux cytokines" n'ont pas encore été élucidés. Nous avons utilisé trois différents modèles de souris transgéniques portant le TCR P14, PMEL ou 8.3-NOD sur les lymphocytes T CD8+ afin d’étudier les mécanismes moléculaires suite à la pré-stimulation aux cytokines. Les cellules T CD8+ portant le TCR transgénique amorcées avec les cytokines, possèdent une augmentation globale des protéines tyrosine-phosphorylés après stimulation du TCR par rapport aux cellules naïves. Cette augmentation de la phosphorylation de la protéine tyrosine a été associée à une augmentation de l'expression de CD8, et a été moins prononcé lorsque CD8 a également été réticulés avec le TCR. Ceci suggère que l'amorçage aux cytokines peut prédisposer le TCR et CD8 à colocaliser, ce qui renforcerait la phosphorylation des chaînes du TCR par la kinase Lck associée à CD8. Les lymphocytes T CD8+ amorcées aux cytokines présentent également des quantités accrues de radeaux lipidiques plasmatiques à la membrane, qui organisent la plate-forme de signalisation du TCR au cours de la stimulation antigénique. L’amorçage aux cytokines des lymphocytes T CD8+ a également augmenté la localisation de CD45, une phosphatase qui diminue l’inhibition automatique de la Lck dans les radeaux lipidiques. Cependant, l'amorçage aux cytokines n'a pas d'incidence sur la capacité des cellules CD8+ T pour former des conjugués avec les cellules présentatrices d'antigène puisées avec des peptides apparentés. En conclusion, ces résultats suggèrent que la composition et les fonctions des radeaux lipidiques peuvent moduler la sensibilité à l'antigène via le TCR lorsque les lymphocytes T CD8+ ont été pré-stimulés aux cytokines.

This essay is about commercialization as a concept and expression in journalism, since there is a concern that what sells is what have been put on the agenda.  Journalisms main purpose is to provide citizens with an insight into the world beyond their own experiences and give people a social perspective. Commercial materials are often available in many different media, some people say that the commercialization threaten democracy and impair quality journalism.   As more people choose to consume and read the newspaper over the weekend the purpose of this essay is to examine if the commercialization increased in the newspaper Aftonbladet during weekends / holidays, and to investigate how much the commercialization takes place in the newspaper. We also wanted to see which news topic that permeated the newspaper. Through a quantitative content analysis we investigated the empirical material gathered during 14 days (230415-060515) of the daily press Aftonbladet, where the advertisements and articles were analyzed units. Altogether, it became 1115 units of analysis that showed that the commercialization increased by 6% during weekends / holidays. The survey also showed that the newspaper Aftonbladet consists of nearly half commercialization and the news topic entertainment and ads were the dominant subjects. With agenda setting theory and priming we were able to analyze and discuss what was found.

Shape Memory Alloys (SMAs) have been demonstrated to be effective actuator elements in a wide range of applications, such as robotics, medicine, aerospace and automotive. Enabled by the unique thermo-mechanical properties of SMAs, these actuators offer the advantages of light weight, high power-to-weight ratio and a simple actuation mechanism compared to traditional actuator types. At the same time, the widespread adoption of the SMA actuator remains elusive as its low power efficiency and complex hysteretic behaviour often render it an impractical means of actuation. These actuators also exhibit a slow response speed and their response is highly sensitive to changes in the external environment, namely ambient temperature and mechanical stress, thus complicating their control. Position, force or temperature sensors may be used to facilitate feedback control, but at the cost of increasing the overall size and complexity of the system. The difficulties caused by the hysteretic behaviour can be largely avoided when SMA wires are used as on-off actuators, making SMAs well suited for such applications. However, they may still be subject to a wide range of dynamic operating conditions that would impact their actuation time, and achieving a consistent actuation time is often highly desirable. This thesis presents the synthesis of a nitinol SMA actuator control system which uses electrical resistance feedback to enable a fast response speed and robustness to disturbances in the external environment. A study of the resistance behaviour of SMAs is discussed first. The design of an adaptive controller and the experimental evaluation of its performance are described in detail next. The objective of the SMA actuator control system is to achieve a consistent and fast actuation time throughout the range of operating ambient temperature and stress. The control system is implemented experimentally and shown to be quite successful.