Cette thèse revisite les relations entre les processus attentionnels visuels et la perception de qualité. Nous nous intéressons à la perception de dégradation dans des séquences d’images et leur impact sur la perception de qualité. Plutôt qu’un approcha globale, nous travaillons à une échelle spatio temporelle fine, plus adaptée aux décisions des encodeurs vidéo. Deux approches liant attention visuelle et qualité perçue sont explorées. La première, suit une approche classique, de type pondération des distorsions. Ceci est mis en relation avec des scénarios d’usage comme le streaming interactif ou la visualisation de contenus omnidirectionnels. Une seconde approche nous amène à introduire le concept de disruption visuelle (DV) et sa relation avec la perception de qualité. Nous proposons d’abord des techniques permettant d’étudier les saccades résultantes de la DV à partir par de données expérimentales oculométriques. Nous proposons ensuite un modèle computationnel de prédiction de la DV. Une nouvelle mesure objective de qualité est ainsi introduite nommée "Disruption Metric" permettant l’évaluation de la qualité locale de vidéos. Les résultats obtenus trouvent leurs applications dans de nombreux domaines tels que l’évaluation de qualité, la compression, la transmission perpétuellement optimisée de contenus visuel ou le rendu/visualisation foéval. / This thesis revisits the relationship between visual attentional processes and the perception of quality. We mainly focus on the perception of degradation in video sequences and their overall impact on our perception of quality. Rather than a global approach, we work in a very localized spatio-temporal scale, more adapted to the decision-process in video encoders. Two approaches linking visual attention and perceived quality are explored in the thesis. The first follows a classical approach, of the distortion weighting type. This is very useful in certain scenarios such as interactive streaming or visualization of omni-directional content. The second approach leads us to the introduction of the concept of visual disruption(DV), and explore its relation to perceived quality. We first propose techniques for studying the saccades related to DV from experimental oculometric data. Then, a computational model for the prediction of DV is proposed. A new objective measurement of quality is therefore born, which we call the "Disruption Metric" : that allows the evaluation of the local quality of videos. The results obtained, find their applications in many fields such as quality evaluation, compression, perpetually optimized transmission of visual content or foveated rendering / transmission.

In recent years, lower-chlorinated, airborne congeners of polychlorinated biphenyls (PCBs) have evolved as an emerging class of potentially hazardous environmental contaminants. Previous work has demonstrated that sulfation is a major metabolic pathway for these PCBs in vitro and in vivo; however, their metabolic fate and toxicities have not been explored. Hypothyroxinemia is among the most prevalent adverse health effects associated with PCB exposure in human populations and is an assumed cause of a variety of neurodevelopmental effects observed in infants following prenatal PCB exposure. The displacement of L-thyroxine (T4) from binding sites on transthyretin (TTR), a major T4 transport protein and trans-placental carrier of thyroid hormones, is thought to be a significant contributing factor in PCB-induced hypothyroxinemia. Structural similarities between sulfated metabolites of PCBs and T4 led to the central hypothesis that PCB sulfates are bioactive metabolites that exhibit high affinity binding to T4 binding sites on human TTR. An examination of the ability of six lower-chlorinated PCB sulfates to bind to human TTR in vitro, as well as subsequent computational modeling, revealed that these compounds interact with the high-affinity binding site in a non-covalent manner and with affinities comparable to T4. Corroborating evidence for the binding of PCB sulfates stems from their ability to inhibit the formation of TTR amyloid fibrils through stabilization of the protein's native conformation. Fibrillar TTR aggregates are the cause of amyloidoses like senile systemic amyloidosis, familial amyloid polyneuropathy and familial amyloid cardiomyopathy. All PCB sulfates examined were effective inhibitors of TTR fibrillogenesis with equal or higher efficiencies than some of the best previously described inhibitors. In vivo exposure of male Sprague-Dawley rats to a model PCB sulfate, 4-PCB 11 sulfate, resulted in rapid and widespread distribution of the metabolite to various organs, including the brain. Consequently, there is a strong indication for a potential role of PCB sulfates in thyroid disruption and inter-tissue transport of PCBs, and the binding of PCB sulfates to TTR may also provide structural information for improved design of anti-amyloid therapeutics. To date there are no analytical procedures for the quantification of PCB sulfates available, and exposure levels in human populations remain unknown. This study provides, for the first time, evidence that PCB sulfates, if present in human serum samples, are not extracted by current standard protocols for the analysis of PCBs and their metabolites. Consequently, PCB sulfates may have been overlooked in the past decades resulting in potential underestimation of total PCB exposure levels in exposed populations. Based on this finding, an efficient approach for the quantitative extraction of PCB sulfates from a variety of biological samples was developed. This procedure, coupled with quantitative mass spectrometry, has been validated for the future screening of human serum samples, and it was successfully applied to determine the tissue distribution and elimination profile of 4-PCB 11 sulfate in male Sprague-Dawley rats.

Thesis (MTech (Business Administration))--Cape Peninsula University of Technology, 2020 / The research was focused on business continuity management as a key discipline towards building a resilient Western Cape Government. It provided an opportunity to identify existing business continuity processes to determine the level of preparedness of the Western Cape Government to ensure continued business due to a disruption. The inability of the public sector to manage and facilitate sound business continuity processes in anticipation of disruptive events have placed it in a position where it would be unable to deliver services to citizens and stakeholders. As the current business environment was continuously evolving, Government as an organization was therefore not immune to change and disruption, whether generated internally or externally. For government to be resilient it required the holistic management of risk but also the ability to adapt and respond to change with a limited impact on the delivery of services. Business Continuity was the core to building and improving organizational resilience. It had been a proven methodology that organizations should embrace as part of a holistic approach to the management of risks and threats. Legislation and/or policies have been drafted for the public sector to guide with the management of risks. As an organ of state and part of the public sector the Western Cape Government was therefore obliged to manage risks in a way that ensured that government was able to continue to render a service both internally and externally with as little impact as possible. Business continuity management identified the priorities of an organization as well as prepared solutions to address disruptive threats. The aim of the study was the exploration of the state of business continuity within the Western Cape Government. The objectives of the study were to: Identify current business continuity processes; Evaluate current business continuity processes; Critically analyse existing business continuity documentation; and Identify the links between business continuity and resilience. The research questions were focused on getting departments to express how business continuity was facilitated; clarity in respect of processes; input source of business continuity documentation; as well as determining whether departments acknowledged the benefits of having business continuity management towards building a resilient Western Cape Government. Previous work reinforced the importance of having sound business continuity processes in place. From the literature it would appear that business continuity in the public sector was fairly new and developmental in nature. Previous work also recognized that each and every organization was unique and as such the process should be aligned with the core functions and/or mandates afforded by legislation and/or policies. The research approach deemed most appropriate for this particular study was the Interpretivist approach. Not only was this approach value laden but it allowed for the exploration of the theory and obtaining of rich in-depth data from the participants. It also allowed for the contextualization of the problem as it related to the business continuity processes within the Western Cape Government. The research method was qualitative using interviews and document analysis as the most suited research instruments to elicit qualitative data required to render the research process as valid. It was concluded that having sound business continuity processes in place would greatly support organizations with the management of disruptions. Business continuity should be a proactive plan to avoid and mitigate risk associated with disruption of operations and needed to be managed in a way that objectives were met. Further to this it should be noted that the resilience maturity of the Western Cape Government remained reactive and concerted efforts towards becoming proactive should be considered.

Polycyclic aromatic compounds (PACs) are a group of chemicals encompassing thousands of different aromatic, alkyl aromatic and heterocyclic hydrocarbons (i.e.- containing N, S, or O- atoms); 16 of which have been designated as priority pollutants due to their toxicity and prevalence. Several studies have highlighted increases in the concentrations of C1-C4 alkylated PACs and heterocyclic aromatic hydrocarbons such as dibenzothiophenes in the atmosphere, water, soil and sediments, plants, wildlife and fish in the Athabasca Oil Sands Region (AOSR). Although there has been considerable research attention related to the toxic, carcinogenic and mutagenic properties of PACs, there is an increasing awareness that these chemicals may also have profound endocrine disrupting properties in wildlife. North American river otter (Lontra canadensis) are good indicators of ecosystem health due to their ecology and sensitivity to environmental pollutants. In this thesis, we first demonstrated the utility of adopting paleotoxicological frameworks in defining environmental baseline levels of PACs and likely biological effects from exposure to these complex environmental mixtures. These methods allowed us to reconstruct historical PAC deposition patterns to impacted areas while simultaneously determining likely biological effects such as endocrine disruption. Next, we showed how PACs exhibited trophic dilution in a Boreal food chain dominated by river otters. Snails, prey and predator fish, as well as river otters were collected from four main study areas in the AOSR in northeastern Alberta, Canada. Bioaccumulation factors such as biota-sediment accumulation factors (BSAF) and trophic magnification factors (TMF) were used to evaluate the partitioning behavior of PACs in the environment and subsequent risks to biota. Our results revealed localized enrichment of certain PACs and subsequent metabolism in higher order vertebrates. Finally, we successfully combined ecotoxicological and physiological analyses paired with population genetic estimates to investigate endocrine disruption and population-level responses to exposure to PACs. River otters are known for their habitual use of latrine sites. Latrine sites represent a unique opportunity for biomonitoring programs to study river otters using indirect sampling methods. In this thesis, PACs were characterized and evaluated in sediment, lower and higher trophic biota with demonstrated impacts on endocrine processes and river otter population health. Effects-based assessments such as the ones presented in this thesis are more powerful for environmental monitoring programs than stressor-based assessment methods (such as describing presence/absence or levels of contaminants) as they provide greater biological context to monitoring data. In turn, these are helpful in selecting triggers for environmental effects monitoring or adaptive management programs.

In intelligent transportation systems, most of the research work has focused on lane change assistant systems. No existing work considers minimizing the interruption of traffic flow by maximizing the number of lane changes while eliminating the collisions. In this thesis, we develop qualitative and quantitative approaches for minimizing the interruption of traffic flow for three lane scenarios and show that we can extend our approach to any random number of lanes. The algorithm we propose in this thesis is able to achieve the maximum number of lane changes provided that only one vehicle per group (novel concept which is described in this thesis) is allowed to change lanes at a time. Simulation results show that our approach provides much better performance when compared with different lane change algorithms without incurring large overhead, and is hence suitable for online use.

No description available.

Programa de Especialización en Negocios para Periodistas, 4ta Ed., de la UPC y Scotiabank, Módulo III: Business-Makingin theDigital Era.

Thyroid hormone is essential for normal brain development and recognition of this has led to universal screening of newborns for thyroid function to ensure that circulating levels of thyroid hormone are within a range known to be supportive of normal growth and mental development. Environmental chemicals that interfere with thyroid function are known to inhibit normal growth and mental development. Work from our lab and from labs internationally demonstrates in animal systems that some industrial chemicals such as PCBs, PBDEs, and others may interact with the thyroid hormone receptor(s) in ways that are not predicted by changes in serum thyroid hormone levels. Our work demonstrates that the enzyme CYP1A1 must metabolize some individual PCB congeners before they can interact with the thyroid receptor. In animals, this requirement appears to be manifested in part by a strong correlation between CYP1A1 and TH target gene expression. Here we present that this pattern extends to humans by demonstrating a correlation between increased CYP1A1 mRNA and an abundance of thyroid hormone responsive gene mRNA.

Studies conducted over the past decades have identified the presence of a greater amount of negative emotional reaction and speech disruption in particular speech situations among children who stutter, compared to those who do not (Brutten & Vanryckeghem, 2003b; Knudson, 1939; Meyers, 1986; Trotter, 1983). Laboratory investigations have been utilized to describe the particular situations that elicit the greatest or least amount of speech concern and fluency failures. More recently, in order to deal with the limitation of laboratory research, the use of self-report tests have gained popularity as a means of exploring the extent of negative emotional reaction and speech disruption in a wide array of speaking situations. However, the availability of such instruments for use with children has been limited. Toward this end, the Speech Situation Checklist (SSC) was designed for use with youngsters who do and do not stutter (Brutten 1965b, 2003b). Past investigations utilizing the SSC for Children have reported on reliability and validity information and provided useful normative data (Brutten & Vanryckeghem, 2003b; Trotter, 1983). Additionally, the findings from those research studies have consistently revealed statistically significant differences in speech-related negative emotional response and speech disorganization between children who do and do not stutter. However, since its initial construction, the SSC has undergone modifications and paucity of normative data for the current American form of the SSC has restricted its clinical use. To fill this void, the revised SSC for children was utilized in the present study to obtain current normative and comparative data for American grade-school stuttering and nonstuttering children. Additionally, the effect of age and gender (and their interaction) on the emotional reaction and speech disruption scores of the SSC was examined. The SSC self-report test was administered to 79 nonstuttering and 19 stuttering elementary and middle-school children between the ages of 6 and 13. Only those nonstutterers who showed no evidence of a speech, language, reading, writing or learning difficulty, or any additional motor or behavioral problems were included in the subject pool. Similarly, only those stuttering participants who did not demonstrate any language or speech disorder other than stuttering were contained in the study. Measures of central tendency and variance indicated an overall mean score of 78.26 (SD=19.34) and 85.69 (SD=22.25) for the sample of nonstuttering children on the Emotional Reaction section and Speech Disruption section of the SSC, respectively. For the group of stutterers the overall mean for Emotional Reaction was 109.53 (SD=34.35) and 109.42 (SD=21.33) for the Speech Disruption section. This difference in group means proved to be statistically significant for both emotional response (t=3.816, p=. 001) and fluency failures (t=4.169, p=. 000), indicating that, as a group, children who stutter report significantly more in the way of emotional response to and fluency failures in the situations described in the SSC, compared to their fluent peers. Significant high correlations were also obtained between the report of emotional response and the extent of fluency failures in the various speaking situations for both the group of nonstuttering (.70) and stuttering (.71) children. As far as the effect of age and gender is concerned, the present study found no significant difference in the ER and SD scores between the male and female or the younger and older group of nonstuttering children. Interestingly, a significant age by gender interaction was obtained for the nonstuttering children, only on the Speech Disruption section of the test.

Micrometeoroids and orbital debris (MMOD) is a growing issue with international importance. Micrometeoroids are naturally occurring fragments of rock and dusk that exist throughout the solar system. Orbital debris is human made material like rocket bodies, paint flakes, and the effluent of spacecraft collisions. Even small MMOD particles on the order of 1 cm in diameter have the potential to destroy critical spacecraft systems. Because of this, MMOD is a threat to all spacecraft in orbit. Even governments that most sternly oppose US international policy have a stake when it comes to minimizing MMOD flux. Space-based assets are essential to support the growing demand for high-capacity communications networks around the world. These networks support services that civilian and military users have grown accustomed to using on a daily basis: Global Positioning System (GPS), Satellite Radio, Internet Backhaul, Unmanned Areal Vehicles (UAVs), and Reconnaissance Satellites [Figure \ref{figure:skynet}]. A sudden loss of these services could degrade the warfighter's capabilities and cripple commercial enterprises that rely on these technologies. Manned space efforts like the International Space Station (ISS) could also suffer as a result of increased MMOD flux.