No description available.

<p> Electrical stimulation of areas in the diencephalon and central grey of the conscious rabbit produces a response of thumping the ground with the hindfeet. The response is not elicitable from the neocortex, striatum or internal capsule. Thumping movements occur mainly after offset of the eliciting stimulus and the likelihood of a response decreases regularly with time, suggesting the decay of a central excitatory state.</p> <p> Central stimulation which produces thumping behaviour tends to be aversive in tests for self-stimulation. Further, the behaviour can be elicited by peripheral electric shock. Therefore thumping behaviour may be a sign of fear in the rabbit.</p> / Thesis / Master of Arts (MA)

The ability to synchronize both the movements and activity rhythms of many interacting individuals is a major component of the repertoire of collective behaviour in social species. Among the many social animals on Earth, ants have some of the most spectacular forms of synchronized behaviour because of their eusociality. One example of this impressive behavioral synchronization in ants is the so-called short-term activity cycle, where the workers inside a nest will move together in rhythmic pulses of activity that are separated by moments of collective rest and inactivity. There are many aspects of short-term activity cycles that are poorly understood. The first chapter of this thesis makes the case for why ants are a useful taxonomic group for studying social synchronization and introduces the phenomenon of ant short-term activity cycles. In chapter 2, I study intraspecific variation in short-term activity cycles and show that colonies’ queens, number of brood items, and number of workers all influence aspects of colony-level activity oscillations. In chapter 3, I show that colonies are capable of synchronizing despite noise in the behaviour of individual ants, and that colonies can modulate between multiple collective rhythms. In the same chapter, I also devised a model to study the role of noise more generally in excitable systems that have properties similar to those in ant colonies. Chapter 4 examined the effect of 24-hour light cycles on circadian activity, and I found that colonies kept in conditions with constant light or darkness had weaker circadian rhythms than colonies in an alternating light/dark regime. However, colonies’ short-term activity cycles were not affected by the external light regime. In chapter 5, I provide evidence that having synchronized rhythms of rest and activity provides a functional benefit for colonies: workers can, on average, more fully inspect the inside of the nest when activity is synchronized because inactive ants aggregate into piles that active ants have difficulty penetrating. In chapter 6, I recount a history of the research into synchronized and rhythmic activity patterns inside ant nests and consolidate the new results from the previous chapters with the existing literature to create an up-to-date review of what we currently know about short-term activity cycles. The work compiled here thereby sheds new light on an enigmatic form of synchronized behaviour in ants, one of the most ecologically important groups of animals on the planet. / Thesis / Doctor of Philosophy (PhD)

A breakthrough ironmaking technology (1Tmk3) produces iron separated from slag by heating coal-iron ore composite pellets at temperatures as low as 1325C in about 10 minutes. Other researchers have studied the melting behavior, including the formation of a dense metallic shell separated from slag but the mechanism has not been yet fully understood. Exploring this knowledge gap was targeted in this study. The initial experiments included heating of composite samples at different temperatures and time intervals. Three coal types and two coal/ore ratios were investigated. By these experiments slag free iron production at low temperature and short time was confirmed. Coal type and coal/ore ratio were found to have a significant effect on melting behavior. The main series of experiments focused on the effect of slag composition mainly CaO and Si02, slag content and reaction time on the melting behavior. The main characterization methods included Optical Microscopy, Energy Dispersed X-ray Analysis (EDX), and simultaneous Differential Thermal Analysis (DTA), and Thermo Gravimetric Analysis (TGA). Despite most of the obtained results being qualitative, this study was successful in exploring some of the most important reasons behind the melting behavior of coal ore composites. It was revealed that the formation of a low melting point slag containing FeO in the core of the pellet and its exudation to the iron shell is responsible for the formation of a dense metallic shell. Densification of iron occurs by reduction of FeO in slag. The rate and extent of reduction is related to the physical properties of slag that in turn is influenced by slag composition. More basic slags tend to have higher rate of FeO reduction in slag. By reduction of FeO in slag, the interfacial tension of the remaining slag with iron increases and slag is separated from iron. / Thesis / Master of Materials Science and Engineering (MMatSE)

The use of polymeric materials in the manufacturing industry has vastly increased since the 1950’s. Because of the large amounts of material involved in modern processing operations, attempts have been made over the years to numerically simulate the processes, in the hope of optimizing operating parameters. However, in contrast to other, more traditional materials such as steel or glass, there is not a well understood connection between the microscopic structure and the (highly non-linear) macroscopic physical response of polymers. Because of this lack of microscopic cause - macroscopic effect knowledge, many descriptions of the physical response of polymers are largely phenomenological ones; that is, the equations used to model the stress/strain response make no attempt to convey information about the microscopic structure of the material. In the present work, five constitutive equations - Mooney-Rivlin, Ogden, G’Sell Two-term Polynomial and K-BKZ - are used to model the stress/strain response of two different polymers commonly used in thermoforming and blowmolding operations, ABS and HDPE, to uniaxial elongation and equibiaxial extension. The models are compared to experimental stress/strain data obtained from an industrial source, and the applicability of their predictions are investigated with regards to variations in strain, strain rate and temperature. Lastly, since the vast majority of real processes involve biaxial, not uniaxial, deformations, the ability of the models to predict equibiaxial response using parameters fit solely to uniaxial data is considered, in order to investigate the possibility of being able to forego the need for expensive, difficult biaxial tests. / Thesis / Master of Engineering (ME)

BACKGROUND: The construct of intention continues to be an important correlate and predictor of physical activity; however, a substantial intention behaviour gap continues to exist. Little literature has examined this gap on a micro-temporal scale, and none have addressed the adolescent population. PURPOSE: The purpose of this thesis is to 1) examine whether there are variations in daily and within day intentions to be physically active in the adolescent population, and 2) whether the intention -physical activity gap is reduced when assessing intention and behaviour on a micro-temporal scale using Ecological Momentary Assessment (EMA). METHODS: This thesis sample included 193 grade 11 students from a large school board in Southern Ontario. Participants responded to 5 EMA prompts for 7 days on their smartphones and wore accelerometers for the duration of the study. Each EMA prompt included a brief questionnaire assessing participant intentions to engage in physical activity. A mixed-effects logistic regression model was used to determine variability in intentions and descriptive analyses were used to examine the intention - behaviour gap. RESULTS: A mixed-effects logistic regression did not indicate differences in intentions between days of the week (coef. = -0.07 SE: 0.07, p=.27) but did indicate that likelihood of reporting intentions significantly decreases over the course of the day (coef. = -.479 SE=.05, p<.01). For daily intentions and physical activity, 89% of daily intenders engaged in subsequent physical activity while 46% of within day intenders engaged in subsequent physical activity. CONCLUSIONS: Findings suggest that there is some variation in intentions and that a micro-temporal time scale measurement serves to reduce the intention - behaviour gap. This adds to our understanding of the relationship between intentions and physical activity. In better understanding this relationship, we can begin to guide interventions that bridge the gap between intentions and physical activity in the adolescent population. / Thesis / Master of Science (MSc) / Despite the known benefits of physical activity, rates remain low amongst adolescents. Previous research has outlined the importance of intentions as a predictor of physical activity; however, an intention behaviour gap persists. The current study examined this gap by assessing variation in intentions over the course of the week and day, and by examining intentions and physical activity closer together in time through the use of a smartphone app. Significant variation was found in intentions within the day to engage in activity. Descriptively assessing intentions and physical activity by measuring them closer together in time indicated a reduction in the daily intention behaviour gap but no significant differences between intentions and behaviour measured frequently within a day. Findings suggest that the intention to behaviour gap may be reduced by assessing intentions and behaviour more frequently and closer together in time. Further research is required to quantify this reduction.

Seabirds are vulnerable to a wide range of impacts at sea and function as important indicators of ocean health. A detailed understanding of their movements and distributions at sea, as well as the types of behaviour in which they engage and the extent to which those activities make them vulnerable to different impacts is critical in effective conservation planning. But their elusive lifestyles and mobility have hampered studies of their at-sea behaviour. Using miniature data loggers deployed on Manx shearwaters Puffinus puffinus this thesis explores the movements, distribution and behaviour of a small-medium pelagic, procellariiform seabird during foraging trips at sea. Foraging distributions were most variable during the pre-laying period when females departed the colony to build their egg. Females foraged close to the colony when local resources were adequate, but more typically foraged in distant shelf edge waters. Males returned frequently to the colony during this period and typically foraged close by, but also in shelf edge waters when local resources were poor. During incubation and chick-rearing the foraging movements of birds tracked from up to four colonies showed considerable inter-annual variability, but were largely constrained to the Irish and Celtic Seas and the inshore waters of west Scotland. Birds from each of the colonies foraged in waters local to their own colony, but also in more distant locations, including the productive Western Irish Sea and Western Irish Sea Front where birds from multiple colonies co-foraged, presumably at high densities. At-sea behaviour was organized into three principal activities representing: (1) sustained direct flight, (2) sitting on the sea surface, and (3) foraging, comprising tortuous flight interspersed with periods of immersion and diving in pursuit of prey. Foraging was highly constrained to daylight hours during which birds engaged in bouts of diving separated by periods of flight or rest on the surface. Most dives were up to 6 m deep, lasting up to 13 s, but some much deeper dives (maximum 55.5 m) were also made. During chick-rearing the use of short and long duration trips may allow parents to control provisioning effort and their own body condition. However, reducing parents’ requirement to provision their chick (by supplemental chick feeding) did not appear to alter the at-sea movements and behaviour of parents, suggesting that at-sea behaviour probably is controlled more by foraging conditions and prey distributions than by the nutritional demands of the chick.

The understanding of the motion of animal groups, such as birds, fish and insects, has been greatly advanced by applying principles of self-organisation – the emergence of global patterns from simple, local, interactions between individuals. The desert locust, Schistocerca gregaria, provides a useful model system for the experimental study of collective behaviour. During plague years, the desert locust can form aggregations extending over hundreds of km. Before developing wings, juvenile locusts form marching ‘bands’ which can maintain group cohesion as they migrate over large distances. In this thesis I investigate locust aggregation, group motion and individual interactions. I also apply the same principles to a study of human behaviour. In Chapter 2, I describe the automated tracking methods that I developed and used to collect the data for the rest of the thesis. In the experiments described in Chapter 3, the relative strengths of the attraction to conspecifics and environmental heterogeneities were explored by presenting groups of locusts with two aggregation sites. I found that locusts had a preference to enter the site with the higher population. The locusts formed dynamic aggregations on the sites; no site was consistently more populated than the other, but individuals were significantly more attracted to the site with the higher current population. In Chapter 4, I consider the effect of marching experience on locust behaviour. Groups of locusts that had experience of directed marching, followed by a sudden reduction in density, behaved indistinguishably from those that had only experienced the lower density throughout, indicating a lack of hysteresis effects in collective responses to change in local population density. In Chapter 5, I investigate a locust’s response to its nearest neighbour. I quantified a locust’s propensity to start or stop moving according to the relative position, orientation and movement of its nearest neighbour. In Chapter 6 the techniques developed studying the locusts were applied to human groups. The response of people to different sized groups was quantified, replicating an earlier study in New York. The response was weaker in Oxford but had the same characteristics of the previous study, showing an initially linear response which saturated. The spatial distribution of gaze copying was anisotropic, tending to occur behind the group.

MSc, Faculty of Science, University of the Witwatersrand, 1969

Although several sustainability implementation frameworks have been proposed, researchers have not yet proposed theories or models to help organisations speed up the rate of sustainability diffusion and narrow the gap between what is known and what is put into use. This study sought to fill this gap by proposing a sustainability diffusion model. The model was developed from an exhaustive review of the corresponding literature. It uses Rogers' (1962) diffusion of innovations theory and Ajzen's (1991) theory of planned behaviour as a theoretical foundation. The model was tested and its structural architecture was validated in three different sustainability contexts; namely, duplex printing in UK universities; sustainable computing in service-based businesses; and sustainability culture in UK universities. The primary data was analysed statistically using SPSS, and structural equation modelling (SEM) in particular was used to validate the structural architecture of the proposed model. The SEM results indicate that the structural architecture of the theory of planned behaviour is well-founded. All the hypotheses that underline the theory's paths were supported. In contrast, the structural architecture of the diffusion of innovations theory was weakly supported. Some of the paths were rejected in at least two occasions. For example, the relationship between pro-sustainability knowledge and attitude was neither statistically significant nor directional. Moreover, several components of the 'verified' model turned out to be statistically insignificant or were rejected altogether. These were knowledge, perceived self interest, perceived persuader legitimacy, perceived consequences, perceived argument quality, trialability and perceived source credibility. Accordingly, once these constructs were removed and the model was restructured in accordance with the results of SEM analysis, an entirely new version of the 'sustainability diffusion model' emerged (See Figure IX-2). The architecture of the new model suggests that in order to speed up the rate of sustainability diffusion, change agents must emphasise the relative advantage, compatibility, subjective norm and the urgency of the pro-sustainability initiative under implementation and de-emphasise any complexities or risks associated with its operationalisation. Unexpectedly, the new version of the proposed model relies more on Ajzen's (1991) theory of planned behaviour as a theoretical foundation than on Rogers' (1983) innovation-decision process model. In other words, the new model maintained almost all the features of the theory of planned behaviour, but it only absorbed some, but not all, of the components of Rogers' innovation-decision process model. Nevertheless, the new model maintained its holistic nature. It still takes into account both the person-specific and innovation-specific factors that influence the diffusion, adoption and actualisation of pro-sustainability behaviours/initiatives.