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Made available in DSpace on 2014-10-09T12:24:58Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:56:15Z (GMT). No. of bitstreams: 1 01288.pdf: 1641778 bytes, checksum: 2707c37a53de3662e15951333b3ff12a (MD5) / Dissertacao (Mestrado) / IEA/D / Escola Politecnica, Universidade de Sao Paulo - POLI/USP

For humans, walking is the principle means of locomotion, or moving from one point to another. While upright locomotion is a human characteristic, the way humans direct their locomotion has not been studied extensively. Prior to the late 1940's, little research or scholarly thought was published regarding locomotion. In 1950, J. J. Gibson published one of the first texts on visual perception, which included theories and research on how humans interpret and react to a world of movement, even as they move within that world. Published research on the topic has been sporadic since then, especially when compared to the volume of work on eye-hand coordination and other eye-brain perception issues. Very little work has been documented on humans moving in a "real world" setting, not laboratory settings or under very specific timing requirements. This study begins by proposing a heuristic framework of human navigation, a description of how humans move from point to point, navigating over and across navigation hazards in the walking path. The heuristic model provides an engineering perspective for the safe design of pedestrian areas, allowing sufficient area for visual recognition of hazards. Two observational studies were performed, one with four different navigation hazards humans come in contact with and the other one with two different hazards that humans pass without contacting. These two classes of hazards involve different perceptual principles. The studies examined the effects of ambient lighting available affected the time required for high attention, fine navigation when approaching a navigation hazard. Specific comparisons between types of navigation hazards were not contemplated, since the perceptual and motor requirements varied considerably among the hazards. Low ambient light levels, representing twilight and night conditions, increase the amount of time required for fine navigation. Analysis of variance (ANOVA) showed a statistically significant difference in the fine navigation time to contact a navigation hazard for stairs travelling down, a 900 turn in the path, and walking downhill with a step midway. ANOVA also showed a significant difference in the fine navigation time to pass a navigation hazard for two different hazards. Under all conditions, post hoc analysis showed Night lighting levels were different from Day lighting levels. Practical applications of this research are in the facilities planning and safety design fields. The individual's locomotion speed combined with the fine navigation time required determines the distance needed for visual recognition of the hazard and preparatory locomotor changes. With extensive research, formalized guidelines and standards can be developed for the safe planning, design and redesign of pedestrian walkways. The human factors engineer could interact knowledgeably with other professional designers to assure that walking paths are designed to meet the human's requirements for safe locomotion. / Master of Science

Small graphite-moderated and gas-cooled reactors have been around since the beginning of the atomic age. Though their existence in the past has been associated with nuclear weapons programs, they are capable of being used in civilian power programs. The simpler design constraints associated with this type of reactor would make them ideal for developing nations to bolster their electricity generation and help promote a greater standard of living in those nations. However, the same benefits that make this type of reactor desirable also make it suspicious to the international community as a possible means to shorten that state?s nuclear latency. If a safeguards approach could be developed for a fuel cycle featuring one of these reactors, it would ease the tension surrounding their existence and possibly lead to an increased latency through engineered barriers. The development of this safeguards approach follows a six step procedure. First, the fuel cycle was analyzed for the types of facilities found in it and how nuclear material flows between facilities. The goals of the safeguards system were established next, using the normal IAEA standards for the non-detection and false alarm probabilities. The 5 MWe Reactor was modeled for both plutonium production and maximum power capacity. Each facility was analyzed for material throughput and the processes that occur in each facility were researched. Through those processes, diversion pathways were developed to test the proposed safeguards system. Finally, each facility was divided into material balance areas and a traditional nuclear material accountancy system was set up to meet the established safeguards goals for the facility. The DPRK weapons program is a great example of the type of fuel cycle that is the problem. The three major facilities in the fuel cycle, the Fuel Fabrication Facility, the 5 MWe Reactor, and the Radiochemical Laboratory, can achieve the two goals of safeguards using traditional methods. Each facility can be adequately safeguarded using methods and practices that are relatively inexpensive and can obtain material balance periods close to the timeliness limits set forth by the IAEA. The Fuel Fabrication Facility can be safeguarded at both its current needed capacity and its full design capacity using inexpensive measurements. The material balance period needed for both capacities are reasonable. For the 5 MWe reactor, plutonium production is simulated to be 6.7 kg per year and is on the high side of estimates. The Radiochemical Laboratory can also be safeguarded at its current capacity. In fact, the timeliness goal for the facility dictates what the material balance period must be for the chosen set of detectors which make it very reasonable.

Small graphite-moderated and gas-cooled reactors have been around since the beginning of the atomic age. Though their existence in the past has been associated with nuclear weapons programs, they are capable of being used in civilian power programs. The simpler design constraints associated with this type of reactor would make them ideal for developing nations to bolster their electricity generation and help promote a greater standard of living in those nations. However, the same benefits that make this type of reactor desirable also make it suspicious to the international community as a possible means to shorten that state?s nuclear latency. If a safeguards approach could be developed for a fuel cycle featuring one of these reactors, it would ease the tension surrounding their existence and possibly lead to an increased latency through engineered barriers. The development of this safeguards approach follows a six step procedure. First, the fuel cycle was analyzed for the types of facilities found in it and how nuclear material flows between facilities. The goals of the safeguards system were established next, using the normal IAEA standards for the non-detection and false alarm probabilities. The 5 MWe Reactor was modeled for both plutonium production and maximum power capacity. Each facility was analyzed for material throughput and the processes that occur in each facility were researched. Through those processes, diversion pathways were developed to test the proposed safeguards system. Finally, each facility was divided into material balance areas and a traditional nuclear material accountancy system was set up to meet the established safeguards goals for the facility. The DPRK weapons program is a great example of the type of fuel cycle that is the problem. The three major facilities in the fuel cycle, the Fuel Fabrication Facility, the 5 MWe Reactor, and the Radiochemical Laboratory, can achieve the two goals of safeguards using traditional methods. Each facility can be adequately safeguarded using methods and practices that are relatively inexpensive and can obtain material balance periods close to the timeliness limits set forth by the IAEA. The Fuel Fabrication Facility can be safeguarded at both its current needed capacity and its full design capacity using inexpensive measurements. The material balance period needed for both capacities are reasonable. For the 5 MWe reactor, plutonium production is simulated to be 6.7 kg per year and is on the high side of estimates. The Radiochemical Laboratory can also be safeguarded at its current capacity. In fact, the timeliness goal for the facility dictates what the material balance period must be for the chosen set of detectors which make it very reasonable.

Indiana University-Purdue University Indianapolis (IUPUI) / There is a well-documented bidirectional relationship between pain and cognitive dysfunction, especially working memory. Despite this extensive body of research, the pain–working memory relationship is poorly understood. Pain catastrophizing – exaggerated negative cognitive and emotional responses towards pain – may contribute to working memory deficits by occupying finite, shared cognitive resources, but this has yet to be investigated. The present study sought to clarify the role of pain catastrophizing (assessed as both a trait-level disposition and state-level process) in working memory dysfunction. Healthy undergraduate participants were randomized to an ischemic pain or control task, during which they completed verbal and non-verbal working memory tests. They also completed measures of state- and trait-level pain catastrophizing. Mediation analyses indicated that state-level pain catastrophizing mediated the relationships of pain group to both verbal and non-verbal working memory, such that participants in the pain group (vs. the control group) catastrophized more about their pain, which then resulted in worse verbal and non-verbal working memory performance. In moderated mediation analyses, trait-level pain catastrophizing moderated this mediation effect for both verbal and non-verbal working memory. Those participants in the pain group who reported greater tendency to catastrophize about pain in general exhibited greater catastrophizing in-the-moment during the pain task, thereby leading to worse verbal and non-verbal working memory performance. These results provide evidence for pain catastrophizing as a putative mechanism and moderating factor of working memory dysfunction in pain. Future research should replicate these results in chronic pain samples, investigate other potential mechanisms (e.g., sleep), and develop interventions to ameliorate cognitive dysfunction by targeting pain catastrophizing.

Due to its negative relation with turnover and the associated costs, job stress is a growing concern within the healthcare industry. By surveying 461 employees of a large Midwestern healthcare system, the present study evaluated perceptions of citizenship pressure (perceived pressure to engage in extra-role job duties) and examined its relationship with job stress and turnover intentions. The sample consisted of direct and indirect patient care providers and was predominately White, females who worked full-time. Hierarchical multiple regression analyses indicated that job stress partially mediates the direct relationship between citizenship pressure and turnover intentions. Specifically, healthcare workers experience job stress and desire leaving positions that make them feel that simply fulfilling their formally prescribed job duties is not enough to be seen as a good employee. Drawing from the theoretical model of psychological resilience, the current study also examined whether employees’ level of trait mindfulness (tendency to focus on experiences without judgment) moderates the identified mediation. Findings from a first- and second-stage moderated mediation analysis suggested that trait mindfulness does not buffer the negative outcomes (i.e., job stress, turnover intentions) associated with citizenship pressure within the healthcare industry. Despite the non-significant results related to mindfulness, significant negative relationships were found between trait mindfulness and each key construct (i.e., citizenship pressure, job stress, turnover intentions). Such findings demonstrate the potential relevance of trait mindfulness in promoting employee resilience within the workplace. Results also contribute to the citizenship pressure literature and highlight the need for additional research, especially within the healthcare industry.

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Made available in DSpace on 2014-10-09T12:24:14Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:10Z (GMT). No. of bitstreams: 1 00032.pdf: 1355141 bytes, checksum: 01f9cb92c30eca4c85591156ed8c22d5 (MD5) / Dissertacao (Mestrado) / IEA/D / Escola Politecnica, Universidade de Sao Paulo - POLI/USP