Patch selection behaviour in the presence of environmental constraints

Habitat selection behaviour is the primary way in which organisms are able to regulate encounters with their biotic and abiotic environment. An individual chooses an area that best meets their current needs, particularly regarding safety and the presence of high-quality food. Several physical aspects of the environment can make it difficult for individuals to assess the relative habitat quality of the areas available, thus leading to suboptimal habitat selection. In this thesis, I investigated the way in which two aquatic habitat constraints - obstacles to movement between patches and turbidity - affected the ability of fish to make optimal patch choices, using threespine stickleback Gasterosteus aculeatus as a model species. Laboratory experiments showed that when movement between patches was hindered by increasingly challenging obstacles, groups of stickleback did not move as freely between the patches, and thus had greater deviations from the predictions of the Ideal Free Distribution (IFD). I also demonstrated that, unlike other species, stickleback do not use turbid environments to avoid predator detection. A trend was seen towards avoidance of a turbid food patch regardless of risk level, although this was not statistically significant. As expected, the stickleback avoided feeding in the presence of a predator regardless of water clarity. Overall, I found that both turbidity and movement constraints can have significant impacts on patch use and distribution in the threespine stickleback. Both turbidity and ease of transit will impact the distribution of ecologically important species like the threespine stickleback, and therefore should be taken into account when studying habitat selection in the wild.

Dynamic safety analysis of managed pressure drilling operations

The exploration and development of oil and gas reserves located in harsh offshore environments are characterized with high risk. Some of these reserves would be uneconomical if produced using conventional drilling technology due to increased drilling problems and prolonged non-productive time. Seeking new ways to reduce drilling cost and minimize risks has led to the development of Managed Pressure Drilling techniques. Managed pressure drilling methods address the drawbacks of conventional overbalanced and underbalanced drilling techniques. As managed pressure drilling techniques are evolving, there are many unanswered questions related to safety and operating pressure regimes. Quantitative risk assessment techniques are often used to answer these questions. Quantitative risk assessment is conducted for the various stages of drilling operations – drilling ahead, tripping operation, casing and cementing. A diagnostic model for analyzing the rotating control device, the main component of managed pressure drilling techniques, is also studied. The logic concept of Noisy-OR is explored to capture the unique relationship between casing and cementing operations in leading to well integrity failure as well as its usage to model the critical components of constant bottom-hole pressure drilling technique of managed pressure drilling during tripping operation. Relevant safety functions and inherent safety principles are utilized to improve well integrity operations. Loss function modelling approach to enable dynamic consequence analysis is adopted to study blowout risk for real-time decision making. The aggregation of the blowout loss categories, comprising: production, asset, human health, environmental response and reputation losses leads to risk estimation using dynamically determined probability of occurrence. Lastly, various sub-models developed for the stages/sub-operations of drilling operations and the consequence modelling approach are integrated for a holistic risk analysis of drilling operations.

Improving safety of nursing staff: challenges and solutions regarding safety for nursing staff in acute care psychiatric settings

Workplace violence is defined as an act of abuse, threatening behaviour, intimidation, or assault on a person in his or her place of employment. Unfortunately, such violence is a reality for nurses. These take the form of physical, verbal, and threating behaviours, and harassment. Violence, particularly verbal abuse, is so prevalent that it is often considered “part of the job” and can contribute to many negative professional and personal effects for nurses. Therefore, it is important to understand what influences an individual to become violent in order to suggest and support initiatives to decrease it. A literature review and consultations with key stakeholders were conducted to gather relevant information regarding violence committed by patients and others visiting mental health care settings. Through data analysis, two relevant themes were revealed: reporting and interventions. Reporting incidents of workplace violence is important to track and quantify aggressive episodes, thus emphasizing its seriousness. Nurses may differ in the perception of what constitutes violence, underreport incidents, and feel a sense of futility when reported violence continues. In addition, cumbersome methods of reporting can be a hindrance to the reporting process. Six areas of potential interventions were identified to increase safety for nurses. These are staffing, de-escalation training, environmental considerations, addictions services, organizational support, and consequences. All findings were summarized in a document to be presented to the leadership of the Mental Health and Addictions program within the local health care authority. The goal is to offer recommendations to lead to a decrease in workplace aggression and increased safety for nurses in the acute care psychiatric setting.