The boreal chorus frog (Pseudacris maculata) is a widespread species but we know little of its ecology. I examined the nature and existence of competitive mechanisms operating between larvae of the boreal chorus frog and wood frog (Lithobates sylvaticus) from field, mesocosm and laboratory venues spanning nutrient concentrations. I assessed larval performance and diet of tadpoles at natural ponds by measuring tadpole growth and size at metamorphosis, and stable isotope ratios for carbon and nitrogen in tadpole tissue to examine if patterns were consistent with the operation of interspecific competition. In mesocosms I measured chorus frog performance in relation to wood frog presence and nutrient enrichment to confirm the occurrence of competition and examine whether nutrient conditions typical of agriculture ponds impact tadpole performance. In the field I compared larval performance and relative abundance between agricultural ponds and those in Elk Island National Park, to examine whether habitat features surrounding ponds in farmlands reduces the abundance of tadpoles and whether tadpole performance results in reduced abundances. Lastly, I examined whether chemical interference by wood frogs occurs by raising chorus frog tadpoles with caged wood frog tadpoles and/or their feces in the laboratory. Chorus frog performance was reduced by presence and abundance of wood frog tadpoles. Resource partitioning in natural ponds and overlap in mesocosms, based on stable isotopic analysis, suggest that resource competition occurs. In mesocosms chorus frog performance was reduced by wood frog tadpoles in fertilized treatments and nutrient conditions at agricultural sites are not in themselves detrimental to these anurans. Performance of chorus frog tadpoles in agricultural ponds was unaffected, whereas wood frogs were larger at metamorphosis in crop ponds. Reduced tadpole abundances of both species at these ponds may be related to habitat features or conditions in croplands. The existence of chemical interference in the absence of physical interaction was confirmed, as chorus frogs exposed to wood frog tadpoles and/or feces had reduced growth and were smaller at metamorphosis which could reduce terrestrial survival and future reproduction. My research contributes to our knowledge on boreal chorus frog ecology and our general understanding of competition between larval anurans. / Ecology

Les poissons demoiselles (Pomacentridae) représentent lune des familles les plus importantes des récifs coralliens ; du point de vue du nombre despèces (> 350) et de leur abondance. Malgré cette importance, très peu détudes ont abordé leur diversité trophique et morphologique. Comme la majorité des poissons coralliens, les demoiselles possèdent un cycle de vie complexe divisé en deux phases : (1) une phase larvaire pélagique et océanique potentiellement dispersive et (2) une phase juvénile et adulte sédentaire associée à lhabitat corallien. La fin du stade larvaire coïncide avec la colonisation du récif. Le milieu océanique offre un habitat relativement homogène pour toutes les larves de Pomacentridae et celles-ci se nourrissent exclusivement de copépodes planctoniques. Au contraire, le récif propose une grande variété dhabitats et de ressources alimentaires. Au cours de leur ontogénie, les demoiselles subissent donc un changement de mode de vie qui doit saccompagner de modifications morphologiques, physiologiques et comportementales pour optimiser leur survie dans chaque environnement. La présente thèse a pour premier objectif de tester lhypothèse selon laquelle la plus grande diversité trophique attendue au stade adulte saccompagne dune plus grande disparité (mesure de la diversité morphologique au sein dun taxon) que chez les larves. Répondre à cet objectif a nécessité dorganiser la recherche selon trois axes. Premièrement, Lanalyse des contenus stomacaux et des isotopes stables du carbone et de lazote chez treize espèces a permis de mettre en évidence trois comportements alimentaires : (1) les « pelagic feeders » qui se nourrissent presquexclusivement de copépodes planctoniques, (2) les « benthic feeders » qui sont des espèces principalement herbivores broutant des algues filamenteuses et (3) un groupe intermédiaire incluant des espèces qui se nourrissent en proportions variables dans le compartiment pélagique et benthique (ex : copépodes planctoniques et benthiques, petits invertébrés vagiles et sessiles, algues filamenteuses). La littérature signale en plus deux demoiselles spécialisées dans la consommation exclusive de polypes de coraux. Deuxièmement, une étude écomorphologique a caractérisé la diversité du squelette céphalique chez les adultes. Les variations de forme de quatre unités du squelette céphalique (le neurocrâne, lunité « suspensorium et opercule », la mandibule et le prémaxillaire) ont été explorées au moyen de la morphométrie géométrique chez quatorze espèces adultes montrant des régimes alimentaires différents. Les résultats révèlent un parallélisme entre la diversité du squelette céphalique et la diversité des régimes alimentaires présent au stade adulte. Dune manière générale, les demoiselles planctonophages possèdent des caractères squelettiques optimisant la prise de nourriture par aspiration (ex : hauts suspensoria et opercules, une large crête supraoccipitale, des mandibules courtes formant une petite bouche). Les espèces brouteuses montrent des pièces squelettiques plus robustes (ex : mandibules hautes et massives, hyomandibulaires larges). Parmi les espèces zooplanctonophages, Chromis viridis et C. acares montrent une morphologie céphalique assez divergente de celle des autres. Leurs caractéristiques squelettiques laissent supposer un mode de prise de nourriture où le poisson capture sa proie en nageant vers elle bouche ouverte (type « ram-suction feeder »). La dentition buccale nest pas toujours corrélée au régime alimentaire. Troisièmement, lontogénie post-colonisation et la variation du niveau de disparité squelettique ont été étudiées et comparées chez huit espèces représentant un échantillon complet de la diversité trophique de la famille. Après la colonisation, les demoiselles subissent des allométries de croissance importantes (40 à 87% des variations de forme). La disparité morphologique est plus grande au stade adulte quau stade de la colonisation pour chaque structure squelettique céphalique. Lensemble des paramètres développementaux étudiés ont subi des changements évolutifs. À la colonisation, les formes larvaires sont déjà spécifiques, probablement à cause de différences dans la durée de vie larvaire pélagique des espèces. Laugmentation de la disparité au cours du développement post-colonisation est essentiellement due à la divergence des patrons allométriques. La longueur des trajectoires ontogénétiques et les vitesses de développement apparaissent comme deux facteurs moins variables. Dune manière générale, peu de liens existent entre les données phylogénétiques ou écologiques (régime, durée de vie larvaire,) et les paramètres développementaux. La diversité du genre Dascyllus illustre des cas de gigantisme. Les méthodes de morphométrie géométrique montrent que les petites espèces et les espèces géantes partagent les mêmes trajectoires ontogénétiques pour le neurocrâne et la mandibule. Au sein de ce groupe, lapparition despèces de grande taille au cours de lévolution résulterait de processus hétérochroniques. La morphologie céphalique larvaire suggère une prise de nourriture de type « ram/suction feeding ». Chez toutes les espèces étudiées, les patrons allométriques révèlent une optimisation du système de prise de nourriture par aspiration au cours du développement. Les demoiselles acquièrent au cours de leur croissance des joues et de opercules proportionnellement plus hauts, une crête supraoccipitale plus grande, des mandibules plus courtes et un processus ascendant du prémaxillaire plus long. Chez les espèces herbivores, dautres changements de forme sont liés à lacquisition de capacités de morsure et de découpe. Par exemple, les mandibules et les suspensoria deviennent plus massifs.

Ideas about "exercise" and "health" have varied over time and across cultures. With the recent Euro-American fitness trend, a growing number of Swedes now take part in some kind of physical activity at Gyms or Fitness Centers. By applying a phenomenological and constructivist approach, the aim of this ethnographic study is to examine the non-profit but also commercial culture of and around this form of exercise. The focus is on how meaning is created, transformed, embodied, and perceived by gym goers as truth, science, knowledge, or even myth. There are two central overlapping concerns in this thesis, both dealing with the interrelation between categories, and status positions. The first part of the thesis deals with the social aspects of movement, such as the definition and categorization of self and others as different types of gym-goers. Related to this are also what is termed critical norms of interpretation of aims and reasons for exercise, such as gaining strength or aesthetic improvement. The other central concern is more specifically focused on the body itself and deals with ideas about exercise, diet, substances, and physiology, that is, how to exercise and how the body works. "The body is made to move", was a common saying at Gyms and Centers, meaning that the human body is physically built to be active. But the techniques and practices of how this movement is performed vary and are sometimes even contradictory. Here sources in the distribution of ideas about the body and body movement are brought out: the Internet, informal and formal instructors in the Gym, as well as gym machines. The method has been participant observation and in-depth interviews with gym goers and instructors at Gyms and Fitness Centers in two middle size towns in Sweden mainly during a year in 2004-2005. Rather than taking sides in the debate on how to exercise, this thesis raises wider questions about the authority to define reality.

In Sweden, children and adolescents with two foreign-born parents constitute 17% of all children in the Swedish population. AIMS: The aims of this thesiswere to collect knowledge of the prevalence of gingivitis, caries and caries associated variables, in the 3-, 5-, 10- and 15-year age groups with two foreign born parents compared with their counterparts with Swedish-born parents in a ten-year perspective (Study I). To investigate the prevalence of caries and caries-associated variables in 15-year-olds in relation to foreign backgrounds and to examine differences in the prevalence of caries in adolescents with foreign backgrounds according to their length of residence in Sweden (StudyII). MATERIAL AND METHODS: In 1993 and 2003, cross-sectional studies with random samples of individuals in the age groups of 3, 5, 10 and 15 years were performed in Jönköping, Sweden. The oral health status of all individuals was examined clinically and radiographically. The children or their parents also answered a questionnaire about their attitudes to, and knowledge of, teeth and oral health care habits. The final study sample comprised 739 children and adolescents, 154 with two foreign-born parents (F cohort) and 585 with two Swedish-born parents (S cohort) (Study I). In Study II, all 15-year-olds(n=143) at one school in the city of Jönköping were asked to participate in the study. The final sample comprised 117 individuals, 51 with foreign-born parents and 66 with Swedish-born parents. All the individuals were interviewed using a structured questionnaire with visualisation e.g. food packages, sweets and snacks. Information about DFS was collected from case records at the Public Dental Service. RESULTS: In both 1993 and 2003, more 3- and 5-yearolds in the S cohort were caries free compared with the F cohort. In 1993, dfs was higher among 3- and 5-year-olds in the F cohort (p<0.01) compared with the S cohort. In 2003, dfs/DFS was statistically significantly higher in all age groups among children and adolescents in the F cohort compared with the S cohort. In 2003, the odds ratio of being exposed to dental caries among 10- and 15-year-olds in the F cohort, adjusted for gender and age, was more than six times higher (OR=6.3, 95% CI:2.51-15.61; p<0.001) compared with the S cohort (Study I). Fifteen-year-olds born in Sweden with foreign-born parents, or who had arrived before one year of age, had a caries prevalence similar to that of adolescents with Swedish-born parents, whereas children who had immigrated to Sweden after seven years of age had a caries prevalence that was two to three times higher (p <0.06) (Study II). Both in 1993 and 2003, the mean of the percentage of tooth sites with plaque and gingivitis was numerically higher in all age groups in individuals with foreign backgrounds compared with Swedish background, except between the 15-year-olds (Study I). CONCLUSIONS: The decrease in caries prevalence, in a ten-year perspective, was less among children and adolescents with foreign-born parents compared with children and adolescents with Swedish-born parents. In 2003, there was statistically significantly more caries in all age groups among children and adolescents with foreign-born parents compared with children and adolescents with Swedish-born parents. Children who immigrated to Sweden at age seven or later had a two to three times higher caries prevalence compared with their Swedish counterparts. The odds ratio for being exposed to dental caries was almost six times higher for 10- and 15-year olds with foreign-born parents compared with their Swedish counterparts. The intake of carbohydrate-rich food was higher among 15-year olds with foreign backgrounds compared to those with Swedish background. There is an obvious need to improve the promotion of oral health care programmes among children and adolescents with foreign-born parents.

No description available.

Fetma och övervikt är ett hot mot folkhälsan. Många med övervikt och fetma försöker gå ner i vikt, men få lyckas bibehålla viktminskningen. Studiens syfte var att ta reda på erfarenheter av betydelsefulla faktorer och strategier för en bestående viktminskning, samt motivation för bibehållandet av vikten. Enligt Self-determination theory (SDT) blir beteendeförändringar bestående om de är autonoma och om motivationen är intern. Åtta kvinnor som deltagit i Itrims viktminskningsprogram intervjuades. Resultatet visade att förändringar i kost, motion och förhållningssätt var för egen vinning och viktiga för en bibehållen vikt. Andra faktorer var kunskap, psykiskt och fysiskt välmående samt vilja. Bibehållandet av viktminskningen var ett självständigt arbete där kunskaper från programmet och från inre reflektion införlivades i livsstilen, vilket överrensstämmer med SDT.

The production of food is responsible for large share of the anthropogenic greenhouse gas emissions. There is a wide range of emissions associated with different food-groups. In particular the production of meat from ruminants causes higher emissions compared to plant-based food. This study compared two different types of meat-free diets (ovo-lacto-vegetarian and vegan) in Sweden and the emission of greenhouse gases that are connected to the aliment and beverages that are consumed in these diets. Dietary records were used to obtain real data on what food is consumed on a weekly basis. On average the food consumed by the vegan sample caused lower emissions that the food consumed by the vegetarian sample. The average vegan diet caused 591 kg CO2e per year whereas the average vegetarian diet caused 761 kg CO2e. The annual difference is thus 170 kg. These findings are in line with existing research although recent studies often used hypothetical diets instead of real data.

The ability of animals to contend with unpredictable seasonal shifts in quality and quantity of prey has implications for the conservation of wildlife. Steller sea lions(Eumetopias jubatus) were subjected to different quantities and qualities of food to determine what physiological and endocrine responses would occur and whether they differed between season (summer and winter) or diet (high-lipid Pacific herring Clupeapallasi vs. low-lipid Walleye Pollock Theragra chalcogramma). Eight females were divided among two groups. One (Group H) were fed herring for 28 days (baseline), then received a reduced caloric intake for a subsequent 28 days (restriction) to induce a 15%loss of body mass. The second (Group P) were also fed herring during the baseline followed by a reduced isocaloric diet of pollock during the restriction. Both groups subsequently returned to their baseline intake of herring for a 28-day controlled re-feeding. The two groups of sea lions lost identical mass during restrictions independent of species eaten, but did differ in the type of internal energy reserve (protein vs. lipids) they predominantly used. Group H lost significantly more lipids and less lean mass than Group P in both seasons. In summer, Group H also increased activity levels and decreased thermoregulation capacity to optimize energy allocation. No such changes were observed for Group P whose capacity to adjust to the reduced caloric intake seemed to have been blocked by the pollock diet. During winter, the sea lions spared energy allocated to activity (especially Group H) and preserved thermoregulation capacity. Changes in body mass was negatively related to free cortisol and positively related to IGF-1 in winter, but only IGF-1 was related to changes in mass in summer when lean mass regulation seemed more important. Levels of IGF-1 were associated with changes in protein metabolism in both seasons for both groups, but changes in body condition were never explained by the measured metabolites or hormones. The capacity to compensate for mass loss was seasonally dependent with sea lions displaying compensatory growth (by restoring lipid stores) in winter but not in summer. Summer appears to be a more difficult season for sea lions to recover from mild nutritional stress. These physiological findings can be used to refine bioenergetic models needed for the conservation of Steller sea lion populations.

Atrial fibrillation (AF) is a common and serious arrhythmia. Current treatments are of limited efficacy, and most do not treat the atrial structural remodeling (hypertrophy and fibrosis) that underlies most clinical AF. Our group has created an experimental dog model of atrial mechanical stretch called the simultaneous atrial and ventricular pacing (SAVP) model (which results in atrial fibrosis and susceptibility to AF) in order to study novel treatments for structural remodeling induced AF. Omega-3 polyunsaturated fatty acids (n3 PUFAs), particularly the marine derived forms eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been shown to be effective in treating arrhythmias (including AF) in some animal studies and clinical trials. The mechanism for this effect of n3 PUFAs is not well understood. In this study we sought to characterize the n3 PUFA effect on AF vulnerability, atrial electrophysiology, histology, and gene expression, and determine relevant mechanisms. Dogs were paced for 0, 2, 7 or 14 days and given n3 PUFAs, olive oil or nothing. Prophylactic n3 PUFAs significantly reduced both AF vulnerability and conduction slowing in SAVP dogs (%AF inducibility: 9.2±8.8 vs. 4.7±6.3; global atrial conduction time: 75±11ms vs. 65±6ms [SAVP 14 days vs. SAVP 14 days with n3 PUFAs, P<0.05 for both comparisons]). Prophylactic n3 PUFAs also reduced inflammation (mean CD18 grade: 2.1±0.8 vs. 1.3±0.6 [SAVP 2 days vs. SAVP 2 days with n3 PUFAs, P=0.055]), hypertrophy (myocyte cross-sectional area: 498±64µm2 vs. 322±111µm2 [SAVP 14 days vs. SAVP 14 days with n3 PUFAs, P<0.05]), and fibrosis (%collagen area vs. unpaced dogs: 178±58 vs. 127±37 [SAVP 14 days vs. SAVP 14 days with n3 PUFAs, P<0.05]). N3 PUFAs were also found to reduce the expression of structural remodeling related molecules such as TGF-β, EGF, ERK and Akt. N3 PUFAs given after some pacing had already occurred were found to be less effective at reducing AF vulnerability and structural remodeling. The results of this study suggest that, in the SAVP model, n3 PUFAs reduce vulnerability to AF by attenuation of adverse structural remodeling at the genetic level.

Urban Aboriginal youth are one of the fastest growing populations in Canada (Statistics Canada, 2008). There is growing concern with the increasing rate of overweight and obesity among Aboriginal youth (Reading, 2009). Although this unique group is quickly growing, and possibly experiencing more ill health than non-Aboriginal youth their voices are currently absent in Aboriginal health literature. Drawing on the voices of urban Aboriginal youth to understand their perspectives is important for the promotion and enhancement of overall health (RCAP, 1996). One specific topic absent from the literature is the influence of culture on body weight, physical activity, and diet for urban Aboriginal youth. (Gittelsohn et al., 1996; Kumanyika, 1993; Marchessault, 1999; Thompson, Gifford, & Thorpe, 2000; Willows, 2005). Culture is seen as the beliefs, behaviours, norms, attitudes, and social arrangements that form patterns in the lives of members (LeCompte & Shensul, 1999, pg 21). The purpose of this study was to examine the influence of culture on body weight, physical activity, and diet for urban Aboriginal youth.<p> This study used the qualitative methodology of focused ethnography. The study setting was an urban Aboriginal high school in Saskatoon, Saskatchewan, Canada. Fifteen participants (11 females, 4 males) took part in this study. Participants were between the ages of 14-21, with a mean age of 16.73. Methods of data collection included semi-structured interviews, informal conversations, talking circles, and participant observation. The researcher spent 10-15 hours a week for eight months on site in the research setting.<p> In this study four themes describe the influence of culture on body weight, diet, and physical activity. These themes were: (i) acceptance of our bodies, (ii) playing together, past and present, (iii) traditions and sharing, and (iv) the struggle. The young urban Aboriginal participants in this study believed that a healthy body weight comes in a variety of sizes. There was a general acceptance in the diversity of healthy body weights and sizes. Group physical activity and competitive activity was favoured among participants. Traditional physical activities such as dancing, hunting, and fishing were cited as important by all participants. Participants believed traditional foods to be healthy and desirable, and those who reported eating traditional foods less frequently desired to eat them more often. Food sharing networks consisting of friends and family were reported as a way to address food insecurity and acquire traditional foods from the participants home reserves. In this study barriers to physical activity and diet for urban Aboriginal youth were income, location or residence, and transportation. Participants attempted to overcome them when it was possible, which highlights a resiliency among urban Aboriginal youth.<p> In conclusion, this study offers valuable information on the influence of culture on body weight, physical activity, and diet for urban Aboriginal youth. Participants in this study engaged in a variety of traditional and cultural activities. These activities increased the healthy eating habits and physical activity levels of the participants. Thus, cultural engagement may be a health enhancing mechanism for urban Aboriginal youth in Canada.