<p>Researchers have long assumed that black widow coloration functions as a warning signal to avian predators. However adult female black widow coloration does not resemble typical warning coloration in two distinct ways. First, black widows are less colorful than most other documented aposematic species. Second, the hourglass shape of an adult female varies both between species and within a site. Here I examine the ultimate causes and consequences of North American black widow coloration. </p><p>In chapter two I present data that suggest that black widow coloration not only functions as an aposematic signal to avian predators, but has also been selected to be inconspicuous to insect prey. In choice experiments with wild birds, I found that the red-and-black coloration of black widows deters potential predators: wild birds were ~3 times less likely to attack a black widow model with a red hourglass than one without. Using visual-system appropriate models, I also found that a black widow's red-and-black color combo is more apparent to a typical bird than typical insect (Euclidean color distance ~2.2 times greater for birds than insects). Additionally, an ancestral reconstruction revealed that red dorsal coloration is ancestral in black widows and that at some point some North American black widows lost their red dorsal coloration (while maintaining the ventral hourglass). Behaviorally, differences in red dorsal coloration between two North American species are accompanied by differences in microhabitat that affects how often a bird will view a black widow's dorsal region. All observations are consistent with a cost-benefit tradeoff of being conspicuous to potential predators while being inconspicuous to prey. I suggest that avoiding detection by prey --- combined with Müllerian mimicry --- may help explain why red-and-black aposematic signals occur frequently in nature.</p><p>In chapter three, I examine the variation in hourglass shape. Classical aposematic theory predicts near uniformity in warning signal appearance because a uniform signal is easier to learn to avoid than a variable signal. However the shape of the hourglass of North American black widows appears to vary both within and between sites in ways that are inconsistent with classical aposematic theory. Using 133 black widows of three different species from nine sites across the United States, I quantified the variation in hourglass shape and examined how Müllerian mimicry, species type, and condition each influenced hourglass shape. A principle components analysis revealed that 84.5% of the variation in hourglass shape can be explained by principle components 1, 2, and 3, which corresponded to hourglass size (PC1), the separation between hourglass parts (PC2), and the slenderness of the hourglass (PC3). Both a black widow's condition and species significantly predicted hourglass shape; however I found no support for localized Müllerian mimicry within different geographical regions. My results suggest a relaxed role for selection on hourglass shape. I discuss several hypotheses that could explain the variation in hourglass morphology including that potential predators may avoid any red markings rather than an exact shape (categorical rather than continuous perception).</p><p>In chapter four I expand on my work from chapter two to examine the eavesdropper's perspective on private communication channels. Private communication may benefit signalers by reducing the costs imposed by potential eavesdroppers such as parasites, predators, prey, or rivals. It is likely that private communication channels are influenced by the evolution of signalers, intended receivers, and potential eavesdroppers, but most studies only examine how private communication benefits signalers. Here, I address this shortcoming by examining visual private communication from a potential eavesdropper's perspective. Specifically, I ask if a signaler would face fitness consequences if a potential eavesdropper could detect its signal more clearly. By integrating studies on private communication with those on the evolution of vision, I suggest that published studies find few taxon-based constraints that could keep potential eavesdroppers from detecting most hypothesized forms of visual private communication. However, I find that private signals may persist over evolutionary time if the benefits of detecting a particular signal do not outweigh the functional costs a potential eavesdropper would suffer from evolving the ability to detect it.</p> / Dissertation

When there is information overload on the visual modality, another system of warnings must be adopted to prevent potential risks—tactile warning systems present a viable alternative. Building on work on design approaches for auditory warning systems that match appropriate warnings to the severity of risk, this thesis presents an approach to design tactile warnings based on perceived urgency. To do this, I use a subjective rating technique. I performed three experiments to demonstrate this approach. Our research approach uses subjective rating technique to evaluate perceived urgency. Three experiments were conducted to design tactile warnings with a tactile interface developed by attaching a grid of tactors on a vest. In Experiment 1 and 2, I evaluated perceived urgency of several warning designs with three important parameters of tactile warnings with subjective rating. In Experiment 3 I examined one warning design in the context of flight simulation. The results of Experiment 1 and 2 showed that participants can discriminate between all levels of perceived urgency from most warning parameters. In Experiment 3, the results showed that selected warning design was correctly mapped with the severity of most events. The findings suggest that tactile warnings based on perceived urgency can be a possible approach, but further studies will be required to evaluate different parameters of tactile warnings.

As shisha smoking is increasing globally, the need for a critical action to control shisha smoking consumption becomes crucial. Despite the success of cigarette warning labels in increasing smokers' awareness of the negative health effects of smoking and in motivating smokers to quit, nothing is known about the potential impact health warning labels may have on shisha users. The current study investigated the perception of effectiveness of text-only versus graphic warning among shisha smokers. This study sought to examine the impact of viewing health warning labels on perceived susceptibility and severity of shisha smoking health hazards, on motivating intentions to quit, and on changing the pattern of shisha smoking. Eligible participants first completed an online baseline questionnaire, and were then randomly assigned to one of three conditions:a control condition, in which they viewed nutrition labels (n=100) , or one of two experimental groups in which they viewed Text- only warning labels (n=117), or they viewed Graphic warning labels (n=125). In each of these three conditions, participants viewed six health warning labels and rated them using likert scale questions immediately following each label. Two weeks later, participants were invited to complete an online follow-up questionnaire. The findings indicate that Graphic tobacco warnings grab participants' attention and elicit unfavourable emotional reactions. Although there was a relatively little impact of viewing health warnings on subsequent shisha use, Graphic warnings significantly improved some of the participants' health knowledge .In addition, Graphic warnings significantly increased smokers' beliefs that shisha is harmful to health and dangerous to non-smokers. Patterns of the findings revealed that quit intentions were relatively higher among those who viewed Graphic warning labels. To our knowledge, this study is the first to examine the effect of health warnings on shisha smokers. Overall, findings provide modest support for the efficcacy of shisha warnings on establised users. Findings imply that packaging and labelling policies for shisha and shisha products require additional development. Further examination of specific themes and contents of health warnings directed specifically to shisha smokers in different cultural settings will be critical to ensure the relevance of health warnings in distinct cultural settings.

Thesis (M.Sc.)--University of Waikato, 2007. / Title from PDF cover (viewed April 8, 2008) Includes bibliographical references (p. 114-119)

Thesis (M.A.)--Baylor University, 2008. / Includes bibliographical references (p. 121-126).

In partial fulfillment of requirements for the degree of Master of Arts in Security Studies / "June 2010." Includes bibliographic references, p. 43-45.

Typescript. Includes vita and abstract. Includes bibliographical references (leaves 158-164). Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.

The term ‘tipping event’ is used to describe a certain class of phenomena as observed in many different fields of science. It refers to an event where a gradual change of external forcing causes a sudden, large, often unwanted, transition to the state of the system. Some examples of known tipping events in science include: Arctic sea ice melting (climate), epileptic seizures (biology), collapse of ecosystems and populations (ecology) and market crashes (finance). Three mathematical mechanisms for tipping events have been proposed in the literature: bifurcation-, noise- or rate-induced tipping. Recent research has focused on developing early-warning indicators to potentially offer forewarning, which can extract from output time series whether the external forcing approaches a critical level at which tipping occurs. Two commonly used early-warning indicators are an increase of autocorrelation and variance in the time series data for the system’s output. The theory behind the presence of these indicators is the loss of stability of the system’s current state known as ‘critical slowing down’ for the approach of a bifurcation-induced tipping. Rate-induced tipping occurs when the external forcing reaches a critical rate instead of level. For rate-induced tipping there is no loss of stability of the system’s current state and therefore it is not clear if the early-warning indicators should exist. In this thesis we investigate the presence of early-warning indicators for models that show rate-induced tipping with additive noise. We also explore a technique for determining the most likely time of tipping using optimal paths for escape. Research has mainly focussed on testing the early-warning indicators for examples of known tipping events in the past. The ultimate aim of early-warning indicators would be to have the ability to predict future tipping events. Using the early-warning indicators in isolation is susceptible to incurring false alarms and missed alarms. We present a method for approximating the probability of experiencing rate-induced tipping with noise for slow to moderate drift speeds.

The aim of this study is to propose an alternative approach in prognostics for airborne avionics system in order to enhance maintenance process and aircraft availability. The objectives are to analyse the dependency of avionic systems for fault propagation behaviour degradation, research and develop methods to predict the remaining useful life of avionics Line Replaceable Units (LRU), research and develop methods to evaluate and predict the degradation performances of avionic systems, and lastly to develop software simulation systems to evaluate methods developed. One of the many stakeholders in the aircraft lifecycle includes the Maintenance, Repair and Overhaul (MRO) industry. The predictable logistics process to some degree as an outcome of IVHM gives benefit to the MRO industry. In this thesis, a new integrated numerical methodology called ‘System Level Airborne Avionic Prognostics’ or SLAAP is developed; looking at a top level solution in prognostics. Overall, this research consists of two main elements. One is to thoroughly understand and analyse data that could be utilised. Secondly, is to apply the developed methodology using the enhanced prognostic methodology. Readily available fault tree data is used to analyse the dependencies of each component within the LRUs, and performance were simulated using the linear Markov Model to estimate the time to failure. A hybrid approach prognostics model is then integrated with the prognostics measures that include environmental factors that contribute to the failure of a system, such as temperature. This research attempts to use data that is closest to the data available in the maintenance repair and overhaul industry. Based on a case study on Enhanced Ground Proximity Warning System (EGPWS), the prognostics methodology developed showed a sufficiently close approximation to the Mean Time Before Failure (MTBF) data supplied by the Original Equipment Manufacturer (OEM). This validation gives confidence that the proposed methodology will achieve its objectives and it should be further developed for use in the systems design process.

xiii, 164 p. : ill. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / Research in the warnings literature has investigated several factors that may affect motivation to comply with the information contained in warnings. However, little research in this area has examined the role that emotion may play in motivating behavior. Three studies were conducted to determine whether participants had an emotional response to warning labels, and, if so, whether the activated emotions were related to behavioral intentions. In Study 1 ( N = 202), participants were asked to imagine themselves in specific situations in which they needed to use particular products. They were then presented with actual warning labels from common consumer products. Both before and after presentation of the warning, participants were asked to rate the extent to which they felt specific emotions and their behavioral intentions. For the majority of the products, surprise and fear increased after exposure to the warning labels. In addition, fear predicted likelihood of use for 9 of the 12 products. In Study 2 ( N = 200), the general framework of the Extended Parallel Process Model (Witte, 1992) was used in an attempt to manipulate fear responses to the warning labels. Four warning labels were created by varying severity of the consequences (low, high) and efficacy of the precautionary instructions (low, high). Participants exposed to the high severity/high efficacy warning label reported higher levels of fear than those in the other three conditions. Fear was negatively correlated with likelihood of use, but positively correlated with precautionary intent. Study 3 ( N = 256) was conducted in an effort to replicate the findings of Study 2 and determine whether the findings would generalize when the four warning labels were paired with a different consumer product. Participants in the high severity conditions reported higher levels of fear than those in the low severity conditions. Again, fear was negatively correlated with likelihood of use and positively correlated with precautionary intent. Possible reasons for the different effects of severity and efficacy on the fear responses for Studies 2 and 3 are explored. Implications of the findings, study limitations, and directions for future research are discussed. / Committee in charge: Robert Mauro, Chairperson, Psychology; Sara Hodges, Member, Psychology; Paul Slovic, Member, Psychology; Debra Merskin, Outside Member, Journalism and Communication