111 research outputs found
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Biological Assessment of the Advanced Turbine Design at Wanapum Dam, 2005
This report summarizes the results of studies sponsored by the U.S. Department of Energy and conducted by Pacific Northwest National Laboratory to evaluate the biological performance (likelihood of injury to fish) from an advanced design turbine installed at Unit 8 of Wanapum Dam on the Columbia River in Washington State in 2005. PNNL studies included a novel dye technique to measure injury to juvenile fish in the field, an evaluation of blade-strike using both deterministic and stochastic models, and extended analysis of the response of the Sensor Fish Device to strike, pressure, and turbulence within the turbine system. Fluorescein dye was used to evaluate injuries to live fish passed through the advanced turbine and an existing turbine at two spill discharges (15 and 17 kcfs). Under most treatments the results were not significantly different for the two turbines, however, eye injury occurred in nearly 30% of fish passing through Unit 9 but in less than 10% of those passing through Unit 8 at 15 kcfs. Both deterministic and stochastic blade-strike models were applied for the original and new AHTS turbines. The modeled probabilities were compared to the Sensor Fish results (Carlson et al. 2006) and the biological studies using juvenile fish (Normandeau et al. 2005) under the same operational parameters. The new AHTS turbine had slightly higher modeled injury rates than the original turbine, but no statistical evidence to suggest that there is significant difference in blade-strike injury probabilities between the two turbines, which is consistent with the experiment results using Sensor Fish and juvenile fish. PNNL also conducted Sensor Fish studies at Wanapum Dam in 2005 concurrent with live fish studies. The probablility of severe collision events was similar for both turbine. The advanced turbine had a slightly lower probability of severe shear events but a slightly higher probability of slight shear
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Laboratory Studies on the Effects of Shear on Fish
The overall objective of our studies was to specify an index describing the hydraulic force that fish experience when subjected to a shear environment. Fluid shear is a phenomenon that is important to fish. However, elevated levels of shear may result in strain rates that injure or kill fish. At hydroelectric generating facilities, concerns have been expressed that strain rates associated with passage through turbines, spillways, and fish bypass systems may adversely affect migrating fish. Development of fish friendly hydroelectric turbines requires knowledge of the physical forces (injury mechanisms) that impact entrained fish and the fish's tolerance to these forces. It requires up-front, pre-design specifications for the environmental conditions that occur within the turbine system, in other words, determining or assuming that those conditions known to injure fish will provide the descriptions of conditions that engineers must consider in the design of a turbine system. These biological specifications must be carefully and thoroughly documented throughout the design of a fish friendly turbine. To address the development of biological specifications, we designed and built a test facility where juvenile fish could be subjected to a range of shear environments and quantified their biological response
Discourses and practices in teaching methods and assessment: Insights from an early career academic
© The Author(s) 2015. Translating the purposes of education into practice is particularly challenging for those who are new or have recently entered academia. By reflecting on my first years of teaching in higher education, I discuss two key aspects of my teaching practice: shifts in choice of teaching methods and a critique of different forms of assessment. Through the discussion, I argue that a teacher needs to be reflective on both these aspects and that such reflection needs to be carried out so that the student develops into a âself-directing,â âself-monitoring,â and âself-correctingâ individual. At the end of the discussion, the relevance of a âproject-based learningâ approach starts to become significant in taking my pedagogical practice forward
Prevalence and determinants of unintended pregnancies amongst women attending antenatal clinics in Pakistan
Background: Unintended pregnancies are a global public health concern and contribute significantly to adverse maternal and neonatal health, social and economic outcomes and increase the risks of maternal deaths and neonatal mortality. In countries like Pakistan where data for the unintended pregnancies is scarce, studies are required to estimate its accurate prevalence and predictors using more specific tools such as the London Measure of Unplanned Pregnancies (LMUP). Methods: We conducted a hospital based cross sectional survey in two tertiary care hospitals in Pakistan. We used a pre tested structured questionnaire to collect the data on socio-demographic characteristics, reproductive history, awareness and past experience with contraceptives and unintended pregnancies using six item the LMUP. We used Univariate and multivariate analysis to explore the association between unintended pregnancies and predictor variables and presented the association as adjusted odds ratios. We also evaluated the psychometric properties of the Urdu version of the LMUP. Results: Amongst 3010 pregnant women, 1150 (38.2%) pregnancies were reported as unintended. In the multivariate analysis ageâ\u3câ20 years (AOR 3.5 1.1-6.5), being illiterate (AOR 1.9 1.1-3.4), living in a rural setting (1.7 1.2-2.3), having a pregnancy interval ofâ=â\u3c 12 months (AOR 1.7 1.4-2.2), having a parity of \u3e2 (AOR 1.4 1.2-1.8), having no knowledge about contraceptive methods (AOR 3.0 1.7-5.4) and never use of contraceptive methods (AOR 2.3 1.4-5.1) remained significantly associated with unintended pregnancy. The Urdu version of the LMUP scale was found to be acceptable, valid and reliable with the Cronbach\u27s alpha of 0.85. Conclusions: This study explores a high prevalence of unintended pregnancies and important factors especially those related to family planning. Integrated national family program that provides contraceptive services especially the modern methods to women during pre-conception and post-partum would be beneficial in averting unintended pregnancies and their related adverse outcomes in Pakistan
Maternal health in resource-poor urban settings: how does women's autonomy influence the utilization of obstetric care services?
Background: Despite various international efforts initiated to improve maternal health, morethan half a million women worldwide die each year as a result of complications arising frompregnancy and childbirth. This research was guided by the following questions: 1) How doeswomen's autonomy influence the choice of place of delivery in resource-poor urban settings? 2)Does its effect vary by household wealth? and 3) To what extent does women's autonomy mediatethe relationship between women's education and use of health facility for delivery?Methods: The data used is from a maternal health study carried out in the slums of Nairobi, Kenya.A total of 1,927 women (out of 2,482) who had a pregnancy outcome in 2004â2005 were selectedand interviewed. Seventeen variable items on autonomy were used to construct women's decisionmaking,freedom of movement, and overall autonomy. Further, all health facilities serving the studypopulation were assessed with regard to the number, training and competency of obstetric staff;services offered; physical infrastructure; and availability, adequacy and functional status of suppliesand other essential equipment for safe delivery, among others. A total of 25 facilities weresurveyed.Results: While household wealth, education and demographic and health covariates had strongrelationships with place of delivery, the effects of women's overall autonomy, decision-making andfreedom of movement were rather weak. Among middle to least poor households, all threemeasures of women's autonomy were associated with place of delivery, and in the expecteddirection; whereas among the poorest women, they were strong and counter-intuitive. Finally, thestudy showed that autonomy may not be a major mediator of the link between education and useof health services for delivery.Conclusion: The paper argues in favor of broad actions to increase women's autonomy both asan end and as a means to facilitate improved reproductive health outcomes. It also supports thecall for more appropriate data that could further support this line of action. It highlights the needfor efforts to improve households' livelihoods and increase girls' schooling to alter perceptions ofthe value of skilled maternal health care
Evaluation of juvenile salmon behavior at Bonneville Dam, Columbia River, using a multibeam technique
In recent years, with increased effort to bypass and guide fragile stocks of juvenile salmon in the Columbia Basin past hydroelectric projects, it has been increasingly important to obtain fine-scale fish behavior data in a non-intrusive manner. The Dual-Head Multibeam Sonar is an emerging technology for fisheries applications that addresses that requirement. It has two principal advantages over traditional hydroacoustic techniques: 1) it allows for simultaneous large-volume coverage of a region of interest, and 2) it affords three-dimensional tracking capability. The use of Dual-Head Multibeam Sonar in this study resulted in an unprecedented insight into fine-scale smolt behavior upstream of a prototype surface collector at the Bonneville Dam first powerhouse in 1998. Our results indicated that outmigrant juvenile salmon had an increased likelihood of milling or holding. This discovery will lead to better design criteria for future bypass and collector systems. Future fisheries multibeam sonar systems will likely be fully integrated systems with built-in real-time tracking capability. These systems may be used to track targets relative to physical guidance structures or other behavior-modifying stimuli such as light, turbulent flow, electrical/magnetic fields, or low-frequency sound and vibration. The combination of fine-scale fish behavior data and environmental parameters will yield better design criteria for the safe passage of listed or endangered species of Pacific salmon
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