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

"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

Nanocomposite ZnxFe1-xO1+δ thin films : wurtzite, rocksalt and spinel phases

Cette thèse porte sur la croissance de films minces d’oxydes de zinc/fer (ZnxFe1-xO1+δ par ablation laser pulsée (PLD) et sur la possibilité de contrôler leurs propriétés structurales et physico-chimiques en variant les conditions d’élaboration : pression d’oxygène et température de croissance, proportions respectives de zinc/fer. Pour de fortes valeurs de x (x > 65%), les films sont monophasés de structure wurtzite type ZnO (films Fe:ZnO), avec une transparence optique dans la gamme UV-visible de 80% mais sans propriété ferromagnétique ; en fonction de leur teneur en fer (1-x), ils évoluent de très bons conducteurs électriques à quasi-isolants. Pour de faibles valeurs de x (x 65%), the films are single-phase with a ZnO-type wurtzite structure (Fe:ZnO films), with 80% optical transparency in the UV-visible range but without ferromagnetic properties; depending on their iron (1-x) content, they evolve from very good electrical conductors to near-insulators. For small values of x (x <15%), the films are also single-phase with a Fe3O4-type spinel structure (Zn:Fe3O4 films). They exhibit very good ferromagnetic properties at ambient temperature as well as good electrical conductivity, the localization effects of charge carriers occurring below the Verwey temperature. The number of antiphase walls can be decreased by a two-step growth, as evidenced by magnetoresistance measurements. At intermediate zinc rates (15% <x <65%), the films are nano-composites. In the case of a coexistence of the Fe:ZnO and Zn:Fe3O4 phases, the good conductivity of Zn:Fe3O4 combined with the multiplicity of epitaxial variants and thus of the interfaces provides a material suitable for thermoelectricity. In the case of a coexistence of the ferrromagnetic Zn:Fe3O4 phase with the Zn:FeO antiferromagnetic rocksalt phase, strong exchange coupling as well as high perpendicular magnetic anisotropy are demonstrated

Recomposed past(s) : historical commissions in the rapprochement processes in Poland (Poland- Germany, Poland-Russia)

L’objectif de notre thèse de doctorat est d’analyser les commissions d’historiens dans les processus de rapprochement en Pologne. Deux cas d’étude sont privilégiés : la commission polono-allemande sur les manuels scolaires et le groupe polono-russe sur les questions difficiles. Ce travail se base sur deux sources principales : une série d’entretiens et des recherches dans les archives. A ce corpuss’ajoutent des sources complémentaires : observations participantes et analyse de discours politiques, de sondages et de la presse.Les points de vue de part et d’autre divergent, voire s’opposent. Les historiens cherchent alors, selon Ricoeur, un récit qui peut favoriser le rapprochement. Ce dialogue sur l’histoire correspond tout à fait à ce qui est demandé aux commissions d’historiens. Dès lors, pourquoi ces commissions ont-elles été créées ? Comment fonctionnent-elles et pourquoi continuent-elles de fonctionner ? Nous formons les hypothèses que, premièrement, ces commissions ont été créées dans un objectif de rapprochement, voire de réconciliation. Deuxièmement, leur fonctionnement — et sa prolongation— dépend de trois variables : le contexte, les mandats, les acteurs.Notre thèse s’articule en cinq points. Les trois premières parties portent sur chacune des trois variables évoquées : contexte, mandats, acteurs. La quatrième partie porte sur les sphères d’influence de ces commissions et les débats qu’elles engendrent : politique et religion, débats publics, débats scientifiques. La dernière partie se concentre sur les projets de ces commissions :l’ouvrage commun ou les centres de dialogue du côté polono-russe, le manuel commun d’histoire du côté polono-allemand.The objective of my PhD thesis is to analyse historical commissions in the processes of rapprochement in Poland. Two cases studies are selected: the Polish-German school book commission and the Polish-Russian group for difficult matters. This work relies on two main sources:a series of interviews and research conducted in the archives. Other sources are complementary to this main corpus: participatory observations, analysis of political discourses, opinion polls and themedia.From one part to another, the points of view differ, or even oppose themselves. Historians then lookfor, according to Ricoeur, a narrative which could favour rapprochement. This dialogue on history matches exactly with what is asked for the historical commissions. Then, why are these commissions created ? how do they work and why do they continue to function ? The first hypothesis assumes that these commissions are created in an objective of rapprochement, or even reconciliation. The second one assumes that their functioning – and its continuation – depends on three variables:context, mandates, actors. My thesis is structured on five points. The first three parts concern each of the three variables cited:context, mandates, actors. The fourth part relates to the spheres of influence of the commissions and the debates they induce: politics and religion, public debate, scientific debate. The last partfocuses on the projects of the commissions: the common book or the centres for dialogue on the Polish-Russian side, the common historical schoolbook on the Polish-German one