The purpose of this experiment was to study the effects of training history on retention and re-acquisition of stimulus control of previously learned behaviors. In Phase I, two pairs of behaviors were alternately trained. Circle and touch behaviors were trained concurrently until two consecutive errorless sessions were run. Spin and down behaviors were trained together in the same manner. Probe sessions, in which all four cues were presented, were conducted each time a pair of behaviors reached this criterion. Training of one pair did not occur until the other pair had reached criterion and probe sessions were run. Despite achieving the designated criterion during training, stimulus control changed during probes. During probe sessions, errors increased under the cues that were not currently being trained. In most cases, the type of errors emitted for each cue was the same as the behavior that was trained concurrently. The number of training sessions required to reach criterion accuracy was high during the first set of sessions and decreased over the course of the experiment. In Phase II, spin and circle behaviors were trained concurrently. The number of sessions required to reach stimulus control criteria remained low, and the number of errors emitted under the spin and circle cues during probe sessions decreased. However, the number of errors increased under the touch cue. In Phase III, a reinforce-all procedure was used instead of extinction to test stimulus control. The highest frequency of errors occurred under the touch cue, but the down error was almost exclusively emitted under every cue during the last several sessions.

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No description available.

Migration is a widespread and complex phenomenon in nature that has fascinated humans for centuries. Connectivity among populations influences their demographics, genetic structure and response to environmental change. Here, I used the loggerhead turtle (Caretta caretta, L.) as a study organism to address questions related to migratory connectivity and carry-over effects using satellite telemetry, stable isotope analysis and GIS interpolation methods. Telemetry identified foraging areas previously overlooked for loggerheads nesting in Florida. Next, I validated and evaluated the efficacy of intrinsic markers as a complementary and low cost tool to assign loggerhead foraging regions in the Northwest Atlantic Ocean (NWA), using both a spatially implicit and spatially explicit (isoscapes) approach. I then focused on the nesting beaches and developed a common currency for isotopic studies based on unhatched eggs, which provide a non-invasive and non-destructive method for more extensive sampling to elucidate isotopic patterns across broader spatiotemporal scales. Lastly, I found that intra-population variations in foraging strategies affect annual and long-term reproductive output of loggerheads nesting in Florida. Understanding geospatial linkages is critical to the fostering of appropriate management and conservation strategies for migratory species. My multi-faceted approach contributes to the growing body of literature exploring migratory connectivity and carry-over effects.

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It is hypothesized that individuals make reproductive decisions based on current assessments of their physiological condition and environmental conditions. For female lesser scaup (Aythya affinis), breeding occurs after an energetically costly spring migration. Increasing fat reserves (i.e., ‘body condition’) prior to breeding allows a female to produce a larger clutch of eggs, but time spent gaining body condition is costly in terms of time allowed to raise ducklings before freezing conditions in the fall. In Chapter 2 I explored rate of pre-breeding body condition gain in female lesser scaup, and how that rate influenced clutch size. Spring phenology, measured by proxy as water temperature, and water depth strongly influenced the rate at which females increased body condition. Early springs with low water levels led to greater rates of body condition gain in female scaup. The higher the rate of body condition gain, the larger the clutch of eggs females produced. Body condition is also an important determinant of breeding in female ducks; females in poor body condition are more likely to forego breeding. I explored how body condition, wetland conditions, and prior experience influence a female’s decision to breed in Chapter 3. Body condition was a strong determinant of when a female bred, with females in good body condition breeding earlier than females in poorer body condition. Habitat conditions were also important, with drought reducing the proportion of breeding lesser scaup females. In Chapter 4 I examined survival costs of reproduction in female scaup. Nesting exposes females to increased predation risk (a concurrent survival cost), and reduced post-breeding body condition may reduce female survival the subsequent non-breeding season (a serial, or ‘downstream’, survival cost). Female survival during breeding and non-breeding seasons was most correlated with breeding season water level on the study site, but in opposite directions. Breeding season survival increased with increasing water levels, while non-breeding season survival declined. High water levels on the study site increased the availability of presumably high-security nesting habitat, and also increased female reproductive effort. The former increased breeding season survival, while the latter reduced non-breeding season survival.

The main idea of this thesis is studying the importance of the carry-over effects and interaction effects in statistical models. To investigate it, a hand-milking experiment in Burkina Faso was studied. In many no electricity access countries, such as Burkina Faso, the amount of milk and milk compositions are still highly  relying on hand-milking techniques and milkers. Moreover, the time effects also plays a important role in stockbreeding system. Therefore, falling all effects, carry-over effects and interaction effects into a linear mixed effects model, it is concluded that the carry-over effects of milker and hand-milking techniques cannot be neglected, and the interaction effects among hand-milking techniques, different milkers, days and periods can be substantial.

My dissertation focuses on (i) the development sputtered films for solid phase microextraction (SPME) and (ii) the comprehensive characterization of materials using a suite of analytical techniques. Chapter 1 reviews the basics of SPME. This chapter also contains (i) a discussion of various sputtering techniques, (ii) a discussion of two techniques I focused on most of my work: spectroscopic ellipsometry (SE) and X-ray photoelectron spectroscopy (XPS). Chapter 2 focuses the major part of my work, which is to prepare new solid phases/adsorbents for SPME via silicon sputtering followed by thermal deposition of a polymer, polydimethylsiloxane (PDMS). PDMS was deposited by a simple gas phase technique which has never before been applied to prepare SPME stationary phases. The coatings were characterized by time-of-flight mass spectrometry (ToF-SIMS), XPS, scanning electron microscopy (SEM), SE, and contact angle goniometry. The extraction efficiencies of ca. 1.8 µm sputtered, PDMS-coated fibers were compared to a commercial fiber (7 µm PDMS) for a series of polycyclic hydrocarbons (PAHs). Large carry-over and phase bleed peaks are observed in case of commercial PDMS-based SPME coatings, which decrease the lifetime and usefulness of these fibers. It is of great significance that our sputtered fibers exhibit very small or negligible carry-over peaks and phase bleed peaks under the same conditions. Chapter 3 focuses on the multi-instrument characterization of copper and tungsten films sputtered by direct current magnetron sputtering (DCMS) and high-power impulse magnetron sputtering (HiPIMS) using a modern sputter source. The resulting films were characterized by energy dispersive X-ray spectroscopy (EDX), XPS, SEM, atomic force microscopy (AFM), SE, and X-ray diffraction (XRD). By EDX and XPS, all the sputtered films only showed the expected metal peaks. By XPS, the surfaces sputtered by DCMS were richer in oxygen than those produced by HiPIMS. By AFM, both surfaces were quite smooth. By SEM, the HiPIMS films exhibited smaller grain sizes, which was further confirmed by XRD. The crystallite sizes estimated by XRD are as follows: 18.2 nm (W, HiPIMS), 27.3 nm (W, DCMS), 40.2 nm (Cu, HiPIMS), and 58.9 nm (Cu, DCMS). By SE, the HiPIMS surfaces showed higher refractive indices, which suggested that they were denser and less oxidized than the DCMS surfaces. Chapter 4 reports characterization of liquid PDMS via SE, which required some experimental adaptations. The transmission measurements were obtained via a dual cuvette approach that eliminated the effects of the cuvettes and their interfaces. Only the reflection measurements were modeled with a Sellmeier function which produced decent fits. Chapters 5 consists of contributions to Surface Science Spectra (SSS) of near-ambient XPS spectra of various unconventional materials including cheese, kidney stone, sesame seeds, clamshell, and calcite. This dissertation also contains appendices of tutorial articles I wrote on ellipsometry and vacuum equipment.

Seabirds are wide-ranging apex-predators and useful bio-indicators of marine systems. Nevertheless, changes are occurring in the marine environment, and seabirds require protection from the deleterious effects of climate change, fisheries, pollution, offshore development, introduced predators and invasive species. The UK supports internationally important populations of seabirds but also has vast wind and wave resources, therefore understanding how seabirds use the marine environment is vital in order to quantify the potential consequences of further exploiting these resources. In this thesis I first describe the range of wave energy converting devices operational or in development in the UK, and review the potential threats and benefits these developments may have for marine birds. I then synthesise data from colony-based surveys with detailed information on population dynamics, foraging ecology and near-colony behaviour, to develop a projection model that identifies important at-sea areas for breeding seabirds. These models show a positive spatial correlation with one of the most intensive at-sea seabird survey datasets, and provide qualitatively similar findings to existing tracking data. This approach has the potential to identify overlap with offshore energy developments, and could be developed to suit a range of species or whole communities and provide a theoretical framework for the study of factors such as colony size regulation. The non-breeding period is a key element of the annual cycle of seabirds and conditions experienced during one season may carry-over to influence the next. Understanding behaviour throughout the annual cycle has implications for both ecological theory and conservation. Bio-logging can provide detailed information on movements away from breeding colonies, and the analysis of stable isotope ratios in body tissues can provide information on foraging during the non-breeding period. I combine these two approaches to describe the migration strategies of northern gannets Morus bassanus breeding at two colonies in the north-west Atlantic, revealing a high degree of both winter site fidelity and dietary consistency between years. These migratory strategies also have carry-over effects with consequences for both body condition and timing of arrival on the breeding grounds. Finally, I investigate the threats posed to seabirds and other marine predators during the non-breeding period by collating information on the distributions of five different species of apex predator wintering in the Northwest African upwelling region. I describe the threat of over-fishing and fisheries bycatch to marine vertebrates in this region, and highlight the need for pelagic marine protected areas to adequately protect migratory animals throughout the annual cycle. In summary, the combination of colony-based studies, bio-logging, stable isotope analysis and modelling techniques can provide a comprehensive understanding of the interactions between individuals and the marine environment over multiple spatial and temporal scales.

La problématique des contaminations croisées (transfert inter-lots de micro-ingrédients : additifs et/ou produits médicamenteux) dans le secteur de l'alimentation animale est entrée, depuis quelques décennies, au cœur des préoccupations de la profession. Ce phénomène se décompose en 2 phases : le dépôt de particules par un lot de fabrication et sa récupération par le/les lot(s) suivant(s). Plusieurs études expérimentales, ont incriminé l’élévateur à godets post-mélangeur dans l’augmentation du niveau de contamination d’une ligne de fabrication. Cet appareil de manutention achemine verticalement des mélanges pulvérulents de diverses matières premières, pouvant contenir, en particulier, des additifs ou des produits médicamenteux. L’objectif de ces travaux est de comprendre dans quelles mesures cet appareil est source de transfert inter-lots, et quels paramètres liés au procédé entrent en jeu. Plusieurs outils ont été mis en place et la réalisation d'un plan d’expériences a permis de mettre en lumière l’impact de certains facteurs sur la contamination croisée :d’une part, le mode de vidange (lié à la vitesse de la sangle) en tête de l’élévateur et l’angle de la bavette de jetée agissent sur la quantité de micro-ingrédient déposée lors du passage d’un lot, et d’autre part, l’espace autour des godets, modifie la capacité du lot suivant à collecter les reliquats.Ces informations définissent une position optimale des paramètres de l’élévateur qui, sur pilote, réduit le niveau de contaminations croisées de 9 à 7 %. Enfin, des observations des champs de vitesses pendant la jetée du produit ont apporté de éléments de compréhension sur mouvements d'air et d'aérosols à l'origine des contaminations. / Carry-over of additives and/or medicated products is a common issue in feed industry and, by extension in most of powder handling industries. Currently carry-over rate of a production line can be accurately defined but the causes are not identified yet. It can be broken into 2 phases : firstly, particle deposit during one batch processing and then, their collecting during the following batches. Experimental studies, carried out on industrial sites or on test benches, charged the bucket elevator situated just after the mixer to be responsible for a significant increase of cross contamination rate of industrial feed production lines. Therefore this work focuses on this handling device. It transfers mixing of several raw materials in powdery forms, which may contain micro-ingredients, especially additives or medicated products. The aim of this study is to understand how process operations affect cross contamination rates during bucket elevator handling. A test bench of this handling device, a reference product and laboratory methods have been setup. Moreover, an experimental fractional factorial design highlights the effects of several process parameters : on one hand the discharge phase on elevator head (linked to belt velocity) and the discharge spout angle act on microingredients deposit mass. On the other hand, spacing between buckets and the leg’s inner surface influences micro-ingredients collected mass. Furthermore, ideal position of process parameters has been defined. By this way, cross contamination rate on the test bench has been decreased from 9 to 7 percent. Finally, velocity fields observations during the discharge phase leads to better understanding of how these process parameters influence cross contamination rate.