Réaliser un système de combustion à petite échelle reste aujourd’hui un défi. L’augmentation du rapport surface/volume favorise les pertes thermiques, contribue à la diminution du temps de séjour et limite la turbulence. Le premier objectif de cette thèse est de comprendre les phénomènes physiques intervenant dans un brûleur centimétrique tourbillonnaire de 8 x10 x 8 mm3 (millimètre cube) et mettre au point des outils numériques adaptés. L’écoulement réactif méthane/air est étudié au moyen de simulations numériques LES. La combustion ne consomme pas l’intégralité du carburant, entraînant un rendement de combustion de l’ordre de 50% et d’importantes émissions de polluants. Le deuxième objectif est d’adapter les performances de ce brûleur. L’enrichissement en hydrogène a montré une amélioration sensible du rendement et une réduction des émissions polluantes. Plusieurs configurations géométriques de la chambre ont aussi été étudiées, ce qui a permis de dégager des axes d’améliorations. / Designing a meso-scale combustion system remains a challenging scientific and technological issue. Increasing the surface-to-volume ratio promotes wall heat losses, reduces the residence time and turbulence intensity. The main objective of this thesis is to understand the physical phenomena involved in the centimetre-sized asymmetric whirl cubic burner of 8 x 10 x 8 mm3 (millimètre cube) and develop specific adapted numerical tools. The methane/air reactive flow is studied using detailed LES. While fuel and air are injected separately, combustion takes place in the premixed regime. However combustion is far from being complete, causing low combustion efficiency and significant emissions of pollutants. The second objective is to adapt in the best possible way the performances of this burner. Hydrogen enrichment of the fuel mixture showed significant efficiency enhancement and reduced pollutant emissions. Several other combustor geometries are also studied, paving the way for future improvement.

Over the years, many interventions have been used to ameliorate couple distress and increase relationship satisfaction. These interventions have been getting shorter in duration. The purpose of this pilot study was to test the feasibility and impact of a brief intervention using a solution-focused approach (SFBT) for couples. The brief intervention included two two-hour consultations. Data were collected from 30 couples and were analyzed using a repeated measures design. The analyses yielded mixed results. There were statistically significant improvements in the areas of individual well-being and relationship knowledge. There were no significant differences in terms of marital satisfaction, communication skills, and readiness to change, although positive trends were observed in this pilot phase. Implications for future research and development are discussed.

Environmental enrichment is a technique used at many captive animal facilities that can improve the well-being of their animals. It seeks to enhance habitat features and promote natural behavior by providing a variety of practical ways for captive animals to control their environmental settings, especially during stressful circumstances. Enclosure features, such as shelter structures, are one tool that promotes wild behavior by adding complexity to an enclosure’s physical environment. Enrichment efforts for captive wildlife are most effective when they are specialized to the biological needs of the animals. Human activity may alter captive animal behavior and utility of enclosure features, and there is concern that human presence can negatively impact the welfare of some captive animals. Captive coyotes (Canis latrans) at the USDA-National Wildlife Research Center (NWRC) Predator Research Facility in Millville, UT, USA, are maintained for research on biology, ecology, physiology and behavior. Coyotes at the research facility are routinely noticed utilizing shelter structures to hide, rest, and display vigilant behavior. Because they regularly use these simple structures, new and more complex enrichment shelter structures were installed to be evaluated. Specific research objectives aimed to assess (1) coyote enclosure utilization and shelter structure preferences, and (2) coyote spatial and behavioral responses to human activity. Using 32 mated coyote pairs rotated through eight 1.5-acre enclosures for 28-day trials over the winter months (January – March) of 2015 and 2016, spatial and behavioral patterns were monitored via the implementation of GPS-collars and live behavioral observations. Coyotes showed preference for shelter structure designs, but still spent most of their time at the perimeter and open areas of their enclosures. Complex structures were preferred over simple structures. Coyotes most often demonstrated inactive and vigilant behavior without human activity, but showed increased vigilance when there was human activity. Human activity also stimulated coyotes to become more active than inactive and reduce their utilization of enrichment structures. Although there was no clear preference for one specific type of enrichment structure, composite evidence from GPS-collars and behavioral data suggest the ramp may have heightened biological suitability. This study advances the knowledge of captive coyote spatial patterns and helps improve environmental enrichment planning for captive animals by exploring effective methods of adding complexity to animal enclosures.

Applications for lab-on-a-chip devices have been expanding rapidly in the last decade due to their lower required volume of sample, faster experiments, smaller tools, more control, and ease of parallelization compared to their macroscale counterparts. Moreover, lab-on-a-chip devices provide important capabilities, including isolating rare cells from body fluids, such as isolating circulating tumor cells from blood or peritoneal fluid, which are not feasible or at least extremely difficult with macroscale devices. Particles experience different forces (and/or torques) when they are suspended in a fluid in a microdevice. A dominant force is the drag force on the particle as it flows through the fluid.  External forces such as dielectrophoresis, the motion of a particle due to its polarization in the presence of a non-uniform electric field, may also be applied. For instance, well-specified mixing or separation of particles can be achieved by using the combination of drag and dielectrophoretic forces. Two major mechanisms for manipulating particles in a microdevice include control of forces applied to the particles, such as those due to electric and velocity fields, and the geometry of the device that affects the nature of these fields. The coupling between the geometry of the microdevices and applied fields makes the prediction of associated forces inside the microdevice challenging and increasingly difficult when the applied field is time-dependent. Understanding the interaction of external forces and particles and fluid is critical for engineering novel microsystems. Determining this interaction is even more complicated when dealing with bioparticles, especially cells, due to their complex intrinsic biological properties which influence their electrical and mechanical properties. Particles with non-spherical geometries further increase the complexity, making drag and other shape-dependent forces, such as dielectrophoretic force, less predictable and more complicated. In order to introduce more complexity to the system and maintain precise control over particle movement and fluid flow, it is essential to have a comprehensive understanding about the mechanics of particles-fluid interaction and the dynamics of the particle movement. Although microfluidics has been investigated extensively, unanswered questions about the effect of forces on the particle remain. Answering these questions will facilitate designing novel and more practical microdevices for medical, biological, and chemical applications Microfluidics devices were engineered for differentiation of subpopulations of cells based on their bioelectrical properties. These microdevices were utilized for separating prostate, leukemia, and three different stages of breast cancer cells from hematologic cells with concentrations as low as 1:106 with efficiency of >95%. The microfluidic platform was also utilized to isolate prostate cancer stem cells (CSCs) from normal cancer cells based on their electrical signature. Isolating these cells is the first step towards the development of cancer specific therapies. The signal parameters required to selectively isolate ovarian cancer cells at different cancer stages were also compared with peritoneal cells as the first step in developing an early diagnostic clinical system centered on cell biophysical properties. Moreover, the effect of non-toxic concentrations of two metabolites, with known anti-tumor and pro-tumor properties, on the intrinsic electrical properties of early and late stages of ovarian cancer cells was investigated. This work is the first to show that treatment with non-toxic doses of these metabolites correlate with changes in cells electrical properties. / Ph. D.

Indiana University-Purdue University Indianapolis (IUPUI) / Imaging genetics is an emerging research field in neurodegenerative diseases. It studies the influence of genetic variants on brain structure and function. Genome-wide association studies (GWAS) of brain imaging has identified a few independent risk loci for individual imaging quantitative trait (iQT), which however display only modest effect size and explain limited heritability. This thesis focuses on mining high-level imaging genetic associations and their applications on neurodegenerative diseases. This thesis first presents a novel network-based GWAS framework for identifying functional modules, by employing a two-step strategy in a top-down manner. It first integrates tissue-specific network with GWAS of corresponding phenotype in regression models in addition to classification, to re-prioritize genome-wide associations. Then it detects densely connected and disease-relevant modules based on interactions among top reprioritizations. The discovered modules hold both phenotypical specificity and densely interaction. We applied it to an amygdala imaging genetics analysis in the study of Alzheimer's disease (AD). The proposed framework effectively detects densely interacted modules; and the reprioritizations achieve highest concordance with AD genes. We then present an extension of the above framework, named GWAS top-neighbor-based (tnGWAS); and compare it with previous approaches. This tnGWAS extracts densely connected modules from top GWAS findings, based on the hypothesis that relevant modules consist of top GWAS findings and their close neighbors. It is applied to a hippocampus imaging genetics analysis in AD research, and yields the densest interactions among top candidate genes. Experimental results demonstrate that precise context does help explore collective effects of genes with functional interactions specific to the studied phenotype. In the second part, a novel imaging genetic enrichment analysis (IGEA) paradigm is proposed for discovering complex associations among genetic modules and brain circuits. In addition to genetic modules, brain regions of interest also grouped to play role. We expand the scope of one-dimensional enrichment analysis into imaging genetics. This framework jointly considers meaningful gene sets (GS) and brain circuits (BC), and examines whether given GS-BC module is enriched in gene-iQT findings. We conduct the proof-of-concept study and demonstrate its performance by applying to a brain-wide imaging genetics study of AD.

Indiana University-Purdue University Indianapolis (IUPUI) / Drylands are the largest terrestrial biome on the planet, and the critically important systems that produce approximately 40% of global net primary productivity to support nearly 2.5 billion of global population. Climate change, increasing populations and resulting anthropogenic effects are all expected to impact dryland regions over the coming decades. Considering that approximately 90% of the more than 2 billion people living in drylands are geographically located within developing countries, improved understanding of these systems is an international imperative. Although considerable progress has been made in recent years in understanding climate change impacts on hydrological cycles, there are still a large number of knowledge gaps in the field of dryland ecohydrology. These knowledge gaps largely hinder our capability to better understand and predict how climate change will affect the hydrological cycles and consequently the soil-vegetation interactions in drylands. The present study used recent technical advances in remote sensing and stable isotopes, and filled some important knowledge gaps in the understanding of the dryland systems. My study presents a novel application of the combined use of customized chambers and a laser-based isotope analyzer to directly quantify isotopic signatures of transpiration (T), evaporation (E) and evapotranspiration (ET) in situ and examine ET partitioning over a field of forage sorghum under extreme environmental conditions. We have developed a useful framework of using satellite data and trend analysis to facilitate the understanding of temporal and spatial rainfall variations in the areas of Africa where the in situ observations are scarce. By using a meta-analysis approach, we have also illustrated that higher concentrations of atmospheric CO2 induce plant water saving and the consequent available soil water increases are a likely driver of the observed greening phenomena. We have further demonstrated that Leuning’s modified Ball-Berry model and RuBP limited optimization model can generally provide a good estimate of stomatal conductance response to CO2 enrichment under different environmental conditions. All these findings provide important insights into dryland water-soil-vegetation interactions.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第19037号 / 農博第2115号 / 新制||農||1031(附属図書館) / 学位論文||H27||N4919(農学部図書室) / 31988 / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 神﨑 護, 教授 北島 薫, 教授 北山 兼弘 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Domestication is accompanied by marked changes in the phenotype of the domesticated form of a species relative to its wild ancestor. The domestic dog and its wild ancestor, the wolf, are a widely used model system to study the effects of domestication on cognition and behaviour. The aim of this study was therefore to compare the behavioural responses of wolves (Canis lupus) and domestic dogs (Canis lupus familiaris) to different odour stimuli. To this end, wooden logs were impregnated with one of four odours and repeatedly placed into the enclosure of a wolf or dog pack. The dogs (n=10) and wolves (n=9) both performed a significantly higher number of interactions with the wooden logs when these were impregnated with real blood compared to the blood odour component trans-4,5-epoxy-(E)-2-decenal, the fruity odour iso-pentyl acetate and the solvent diethyl phthalate. No significant difference in the frequency of interactions per animal was found between the wolves and dogs with any of the four odour stimuli. Sniffing was the most frequent behaviour in both wolves and dogs, followed by licking, biting, toying, and pawing. The only qualitative difference in behaviour was that the dogs, but not the wolves, displayed guarding behaviour when presented with the odorized wooden logs. The results of the present study suggest that domestication had little, if any, effect on olfactory behaviour in domesticated dogs. The results also indicate that odour-impregnated wooden logs are a suitable method of olfactory enrichment for captive wolves and domestic dogs.

Chimpanzees are highly social animals, presenting a wide variety of social interactions among them. In this study, we compared the social dynamics in a group of 20 captive chimpanzees at Kolmården Wildlife Park between two different exhibits: outdoors (summer) and indoors (autumn). Furthermore, different types of enrichment were offered in both environments and we investigated how the presence and the type of enrichment (food-based) affected the social interactions in the group. Then, we used the frequencies of the social interactions to analyse the social dynamics in the group. Our results showed that the chimpanzees had significantly higher frequencies of proximity, allogrooming and displacement in the outdoor exhibit compared to indoor one and higher frequencies of threat and display indoors compared to outdoors. Moreover, we found that associative and affiliative behaviours increased in both outdoor and indoor exhibits when enrichment was absent compared to when it was present and also when enrichment was absent compared to when food-based enrichment was offered. Furthermore, three pairs of individuals, all mother-daughter dyads, were found to have preferred relationships. In the allogrooming network, one female, the only one that was in estrus, was found to be the most common recipient of allogrooming. Finally, the oldest male, father of all offspring, was, as expected, ranked as the most dominant in the group, based on the agonistic interactions. Our results may be used by the zoo staff to further develop their management practices to improve chimpanzees’ welfare.

Background: Vancomycin-resistant enterococci (VRE) is a common nosocomial infection. It classifies as Enterococcus faecalis or faecium carrying vanA or vanB gene that alters the bacterial cell wall hence lowering affinity for Vancomycin. Screening for VRE in Swedish hospitals are performed with stool sample pre-grown in selective broth followed by PCR and culture on selective media. Viasures Vancomycin resistance, Real Time PCR Detection Kit indicates that pre-growth in broth is not needed for the analyze. Aim: Comparison between the PCR kit and the subsequent culture on chromogenic agar with or without pre-growth in selective broth. Method: E. faecium with vanA gen (CCUG 36804) and E. faecalis with vanB gen (ATCC 51299) were suspended in different concentrations and added to ESwab transport medium. Thereafter small samples from the ESwab tube were enriched in selective broth. Samples from both selective broth and ESwab medium were analyzed with Viasures PCR kit on BD-MAX system and cultivated on chromogenic agar. Results: With pre-growth in selective broth the genes were found in every sample regardless of pre-concentration in the ESwab medium. Without enrichment the PCR kit always amplified the genes when the concentration was 40 000 cfu/ml for E. faecium (vanA) and ≥ 10 000 cfu/ml for E. faecalis (vanB). Colonies grew on chromogenic agar in every concentration from both ESwab and selective broth. Conclusion: Culture on chromogenic agar is comparable with or without pre-growth in selective broth but Viasure’s PCR kit is not equal for both methods in lower concentrations of the bacteria.