Alpine thermal dynamics and associated constraints on the behavior of mountain goats in Southeast Alaska

Thesis (M.S.) University of Alaska Fairbanks, 2015Alpine Caprinae, including mountain goats (Oreamnos americanus), have been described to be sensitive to temperature changes within their summer range and consequently may be forced to select habitats that allow for the maintenance of a stable core temperature on warm days. Survival may be inhibited if warm ambient temperatures cause mountain goats to reduce time foraging or if too much time is spent on thermoregulatory habitat selection. I investigated mountain goat behavioral activity budgets across alpine temperature gradients in Southeast Alaska using focal animal sampling and scan sampling techniques. I tested the effects of temperature on mountain goat activity and mountain goat elevation. Coupled with the behavioral investigations, I simultaneously monitored elevational temperature gradients using an array of passive thermistors. By monitoring hourly temperatures and deriving near-surface lapse rates, I demonstrate the utility of downscaled, region-specific temperature-elevation profiles for ecological applications rather than making inferences based on broad spatial models. Except in winter, lapse rates within the study area were between -0.3°C 100m⁻¹ and -0.4°C 100m⁻¹, and were not inclusive of the global mean environmental lapse rate (-0.65°C 100m⁻¹). Mountain goats within the study area demonstrated behavioral conservation of their activity budgets by altering their orientation through space and time, rather than incurring thermal and/or nutritional deficits. In addition, the animals took advantage of cooler temperatures at high elevations to bolster thermoneutrality. I highlight the need for behavioral ecology research that links physiological mechanisms and mammalian life history in an effort to predict the fate of a sentinel wildlife species as it copes with a changing environment. Indeed, such indicator species are invaluable to understanding the dynamics of change in ecosystem structure, function, and phenology. Given current warming trends and projections of changing climate regimes being more pronounced at higher latitudes, there is a marked need to better understand thermoregulatory constraints on faunal behavior and the effect of changing landscapes on the distributions and survival of wildlife populations in Alaska

Staircase-like metamagnetic transitions in phase-separated manganites: influence of thermal and mechanical treatments

Substitutions in the Mn-sublattice of antiferromagnetic, charge and orbitally ordered manganites was recently found to produce intriguing metamagnetic transitions, consisting of a succession of sharp magnetization steps separated by plateaus. The compounds exhibiting such features can be divided in two categories, depending on whether they are sensitive to thermal cycling effects or not. One compound of each category has been considered in the present study. The paper reports on the influence of two treatments: high-temperature annealing and grinding. It is shown that both of these treatments can drastically affect the phenomenon of magnetization steps. These results provide us with new information about the origin of these jumps in magnetization.Comment: accepted for publication in J.Appl.Phy

Development of a dynamic snowmobile model for ride dynamic analysis

Owing to the high magnitudes of vibration transmitted to the snowmobile driver, ride comfort forms a major design requirement. Current development processes are based upon prototyping and sequential field-testing. An analytical model for investigating the dynamic snowmobile behaviour would enhance the designers' efficiency at achieving the desired ride performance. In this respect, only limited efforts have been made thus far. This dissertation research aims at developing a comprehensive, industry-viable ride dynamic model of the snowmobile to help in vehicle development. A nine degrees-of-freedom model was implemented in the ADAMS software through the integration of nonlinear subsystem models, namely, a lumped frame model, detailed suspension representations, a track model, deformable ground model, trail surface representations, a quasi-steady traction model, and a simplified rider and seat model. Four different trails were measured and analyzed, characterizing their roughness in terms of spatial power spectral density. A field test program, undertaken with Bombardier Recreational Products Inc., provided the vehicle response data. Laboratory measurements were performed to obtain static and dynamic properties of the vehicle and its components. The measurements were compared to the model outputs to evaluate its validity, revealing reasonably good agreements for some of the trails, while considerable differences were observed for others. The model was then used to perform a parametric analysis on nine ride-related factors. Following the response surface methodology, with seat surface vertical rms acceleration as response variable, lead to the identification of a range of parameter values reducing acceleration by 58%. The process revealed, among else, the model's high sensitivity

Les facteurs de risque socio-écologiques des comportements agressifs chez les jeunes contrevenants en milieu ouvert

L'objectif de cette étude est de déterminer si les facteurs de risque dynamiques peuvent différencier les contrevenants agressifs et non agressifs au-delà des facteurs structuraux chez les jeunes contrevenants pendant un séjour en milieu ouvert. L'échantillon se compose de 135 jeunes contrevenants. Les résultats des analyses de régression logistique démontrent que les facteurs dynamiques n'ajoutent pas à l'identification des contrevenants agressifs et non-agressifs. Cependant, une des variables structurales s'est avérée significative lors des analyses. La présence de diagnostics concomitants est une variable importante dans la prédiction de comportements agressifs. Une discussion portant sur ces résultats est présentée.statement of responsibility: par Nicole Hébert-LeBlanc.thesis: Thèse (M. A. Psychologie) -- Université de Moncton, Faculté des sciences sociales,bibliography: Bibliogr.: f. [71]-78

"Feed the world" : food, development, aid and hunger in Africa, 1984-1985

This thesis evaluates African reactions to the 1984-85 Ethiopian famine and broader discourses about food, hunger, aid and agriculture through an analysis of reports, editorials and letters in the African press during the height of global concern about famine in Ethiopia. Africa's leaders blamed famine on agricultural underdevelopment as a consequence of the continent's marginality in the global economy. While these discourses revealed how food was a means by which the industrialised world maintained dominance over the developing world, they concealed how African states' political and social divides determined which groups starved and which groups continued to eat. The Ethiopian famine amplified calls for the development of large-scale, technologically-advanced farming as a means to ensure Africa's political and economic independence on one hand, and valorisations of "traditional" African foods on the other. Debates over the fixture of African farming were shaped by a paternalistic attitude towards rural populations, especially women, on the part of Africa's urban elites, and revealed how the production and consumption of food is productive of local and transnational political and social networks. As well as examining discourses about food, I examine how Africans responded to events such as Live Aid, which raised millions of dollars for famine relief. While scholars have criticised these events for ignoring the politics of famine, my research shows how Africans saw these events as speaking to them as political subjects in a way that official relief efforts did not

Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. For example, a key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process versus those that measure fl ux through the autophagy pathway (i.e., the complete process including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase autophagic activity, defi ned as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (inmost higher eukaryotes and some protists such as Dictyostelium ) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the fi eld understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation it is imperative to delete or knock down more than one autophagy-related gene. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways so not all Atg proteins can be used as a specific marker for an autophagic process. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field