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A significantly untapped renewable energy source exists in the world's oceans. It is estimated that if 0.2% of the ocean's untapped energy could be harnessed, it could provide power sufficient for the ...
Citation Citation
- Title:
- Investigation and comparison of generators for dynamic operation in ocean buoys
- Author:
- Schacher, Anthony Clinton
A significantly untapped renewable energy source exists in the world's oceans. It is estimated that if 0.2% of the ocean's untapped energy could be harnessed, it could provide power sufficient for the entire world. Ocean energy extraction is an old concept, and it is currently seeing the benefit of advancing support technologies and an increasing awareness of potential future energy deficits. Girard, in Paris, registered the world's first wave energy device patent in 1799. Over more than 200 years of development, the number of patents has greatly increased and today there are currently more than 1500 ocean wave energy device patents. This thesis presents and examines the concept of using an ocean wave as the prime mover for a buoy-mounted, directly driven, electrical generator. The primary focus will be on two particular generator types, a Permanent Magnet Synchronous Generator (PMSG) and a Wound Rotor Induction Generator (WRIG), and their reactions to a simulated wave profile. The simulations were based on the concept of a directly driven screw, either a roller screw or ball screw, and a sinusoidal wave profile. The development of this thesis moves through four sections: introduction of wave energy, the details of the experimentation that was conducted; the results of those experiments and the comparisons with mathematical models; and finally the conclusion and recommendations for future experimentation in this area. A number of different experiments have been conducted for this thesis on the directly driven buoy generator scenario. They range from baseline control tests, which establish a characterization of the generators, to intricate multi-directional reciprocating drive research. The reciprocating drive scenario is used to simulate a unidirectional direct drive, where one half of the stroke is used to generate electrical power and the energy from the other half of the stroke is stored in inertial mass, such as a spring, or some other similar energy storage device. The experiments were conducted on both the PMSG and the WRIG as was appropriate to their characteristics, to see how each of the platforms reacts to similar prime movers. Experimental data from the PMSG and WRIG investigations will help to home in on which type of generator would be more suitable for a given buoy generator design. The designation will be based on two main factors, the physical generator to drive screw connection, and the power take-off (PTO) system to be implemented between the buoy generators and the electrical utility grid. Additionally, an over-running clutch connection will be implemented to verify the notion of a partial cycle "free-wheeling" generation scheme based on the inertial force of the generator itself. It has been hypothesized that if the inertial force of the generator were greater than the load force from the output connection, then the generator would be allowed to "free-wheel" through half of the wave cycle. This will allow the generator to remain rotating in one direction, as opposed to a directly coupled connection which would force the direction of rotation to oscillate from clockwise to counterclockwise as the buoy driving the generator floated over a wave front. By creating a unidirectional rotation, the ability to use a WRIG becomes much more applicable due to the requirement for fairly high rotational speed for generation. Much like a child's mechanical top, a WRIG will be able to run up to a base speed suitable for generation and then the electrical utility grid connection will be energized. By contrast, the PMSG would likely be used in a reciprocating scenario thereby taking advantage of the intrinsic constant magnetic field, which will produce a usable output at low rotational speeds. It is concluded that each of these generators will have a potential niche to fill in Ocean Energy extraction buoys. Due to the reciprocating nature of the ocean waves and the varying periods and magnitudes, some form of the output conditioning will need to be applied if there are plans for a direct grid connection. The WRIG outputs a fairly constant voltage but the current magnitude varies with the wave profile. If some form of current leveling was introduced and the output current magnitude was made more constant the WRIG will be the prime candidate for a direct grid connection. The PMSG, and its ease of output rectification make it the choice for a rectified transmission to shore scheme, where it can then be inverted to undistorted ac power and connected into the electrical utility grid.
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1362. [Article] Three essays on the economics of malaria
Malaria is the world’s most important parasitic infectious disease, and is a major cause of mortality and morbidity in many developing countries. In this dissertation I study the interaction of malaria ...Citation Citation
- Title:
- Three essays on the economics of malaria
- Author:
- Datta, Saurabh Charles
Malaria is the world’s most important parasitic infectious disease, and is a major cause of mortality and morbidity in many developing countries. In this dissertation I study the interaction of malaria and economic development at both the macro- and micro-economic levels. In the first essay I examine the economic impact of malaria on income per capita using cross-country time-series data for 100 malaria prone countries between the years 1985 and 2001. I try to explain the so-called “malaria gap,” which refers a general difference (gap) in parameter estimates found between macro- and micro-economic studies of the impact of malaria on economic well-being. By using more detailed data and controlling for a larger number of economic determinants of malaria than previous macro-economic studies, I am able to resolve most of the “malaria gap” associated with earlier studies in the literature. I show that the impact of malaria on economic well-being is statistically significant but fairly small, which coincides with the findings of certain recent micro-level studies. Policy implications of these empirical findings are discussed. In the second essay I turn my focus to the fact that malaria itself is an endogenous variable over which households and government have some control. I start with simple plots of data that show that malaria has a negative correlation with national income per capita, whether looking across countries at a point in time, or looking at a single country over time. Some countries have moved steadily over time from an equilibrium characterized by low income and high malaria, to a new equilibrium with a relatively high income and low rate of malaria. I develop and estimate a simultaneous equations model to explain these relationships. I distinguish three potential causal chains: the ability for decreases in malaria to increase income, the ability for increases in income to reduce malaria (reverse causality), and external factors that may lead to both higher income and lower malaria (incidental association). I find that changes in income have a much stronger effect on malaria incidence than the other way around. While a 1% rise in the number of malaria cases per million decreases income per capita by less than 0.01%, a 1% rise in income per capita decreases the number of malaria cases per million by more than 1.1%. If income were just 1% higher, 603,189 cases of malaria could be averted annually in the 100 countries of the sample. In the third essay I take a completely different approach in that I use micro-economic household survey data to examine how farming households in poor, malaria-prone areas respond to an outbreak of malaria. I focus on their choice of cropping pattern, since they may shift away from labor-intensive, high-risk yet high-return crops towards those with lower risk and effort yet much lower returns. Households may also move away from formal jobs with long time commitments towards daily labor type activities in which they only work when healthy. These hypotheses are tested using detailed data for 919 households of the Kagera region in Tanzania over the 1991-94 period. To specify an appropriate econometric model, I first develop a theoretical model that captures the micro-economic processes that I highlight above. The econometric results are generally consistent with the ideas in the theoretical model. Outbreaks of malaria and other natural disasters, such as pest attacks and drought, prompt households to move away from chemical-input- and labor-intensive crops (e.g., sugarcane, tobacco, cotton) towards subsistence (e.g., cassava and sweet potato) and tree crops (e.g., coffee and banana). At the same time, they are found to be depending more on casual labor employment and remittance income, while cutting down expenditures on purchased agricultural inputs and net asset creation.
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1363. [Article] Converting forest biomass to energy in Oregon : stakeholder perspectives on a growing movement
Within Oregon there is considerable interest in the possibility of converting woody biomass to energy. This interest stems from three converging factors: the desire to reduce the threat of uncharacteristic ...Citation Citation
- Title:
- Converting forest biomass to energy in Oregon : stakeholder perspectives on a growing movement
- Author:
- Stidham, Melanie
Within Oregon there is considerable interest in the possibility of converting woody biomass to energy. This interest stems from three converging factors: the desire to reduce the threat of uncharacteristic wildfire by removing excess material from the forests, the possibility to stimulate rural economies that are dependent on forest products, and generation of renewable and/or clean energy from a local source. There have been a number of studies to assess the feasibility of wide-scale conversion of biomass to energy. These efforts have largely focused on technical barriers to the use of biomass for energy rather than social barriers. This study explores the social context of converting forest biomass to energy, through use of semi-structured interviews. Forty interviewees were purposively selected from the following Oregon stakeholder groups: federal and state agencies, elected officials, community organizations, conservation organizations, the forest industry sector, Tribes, energy utilities and non-utility energy experts. Information gained through the interviews was used to meet two research objectives: 1) to understand stakeholders' views on converting forest biomass to energy in Oregon; 2) to identify, from the perspectives of stakeholders, the opportunities for and barriers to converting forest biomass to energy, and potential strategies to overcome the barriers. In addition, there were two secondary objectives: a) to identify areas of common ground and conflict between and within stakeholder groups; and b) to identify policy components that would be necessary in the integration of the forestry and energy industries in Oregon. Among research participants there was wide agreement on what constitutes forest biomass; typically small diameter material that is currently non-merchantable, produced as a by-product of restoration or other forest management activities. There was most agreement that restoration treatments are needed in low-elevation ponderosa pine forests in eastern and southwestern Oregon to reduce the risk of uncharacteristically large and severe wildfire. It is this risk of unusually intense wildfire that many research participants felt was driving this issue in Oregon, rather than potential energy or rural economic development benefits. Many research participants wanted at-risk forests restored to conditions within their historic/natural range of variability, which depended on site specific characteristics, but generally meant fewer trees per acre and inclusion of low-intensity fire. The top three reasons research participants were interested in biomass utilization were the opportunities to generate renewable energy, restore forests, and stimulate economic growth in rural communities. While participants were enthusiastic about these opportunities, they brought up a number of barriers that would have to be addressed before the full suite of opportunities could be realized. The most vital and most challenging barrier was access to supply. Factors making supply more difficult to secure included the expense associated with long transport distances, and that while supply needs to be long-term, continuous, inexpensive, and guaranteed, it is mostly on federal land, where the public is involved in land management decisions and politics plays a role. Another challenge is the long history of contention between parties related to forest products coming from federal land, and these parties would have to all agree that biomass utilization using supply from federal forests is acceptable before supply could be made available. Many research participants suggested that collaboration could allow these projects to be developed in a manner acceptable to all parties. Costs could be federally subsidized to make projects more feasible. Participants encouraged development of pilot projects to move discussion from speculation to actuality. Many research participants expressed more comfort in smaller energy facilities to prevent energy needs from dictating forest management, i.e., to prevent the tail from wagging the dog. The overarching goal of this research is to provide information useful to collaboration groups, policymakers, land managers, communities, and relevant advocacy groups to create a foundation for discussions as forest biomass energy becomes an increasingly prominent issue in Oregon.
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It is critical for wildlife managers to understand the population dynamics of a harvested species, particularly for ungulates, which are a valuable wildlife resource. Due to concerns that mule deer (Odocoileus ...
Citation Citation
- Title:
- Survival Rates and Cause-Specific Mortality of Mule Deer in South-Central Oregon
- Author:
- Mulligan, Elizabeth M.
It is critical for wildlife managers to understand the population dynamics of a harvested species, particularly for ungulates, which are a valuable wildlife resource. Due to concerns that mule deer (Odocoileus hemionus) populations in Oregon were declining, more comprehensive data on population vital rates and the factors potentially affecting them were needed by resource managers. To meet this research need, Oregon Department of Fish and Wildlife implemented a seven year study to investigate habitat use and survival of mule deer in eastern Oregon. From 2005-2012, the agency radiocollared 621 mule deer in south-central Oregon in order to gain more comprehensive information about seasonal movement, seasonal and annual survival, and changes in habitat use for the population. I used the radio-telemetry data from this larger study to investigate mule deer survival rates and cause-specific mortality and the effects of deer seasonal distributions, movement behavior, and environmental factors such as annual and climatic variation. I used known-fate data for 408 adult female radio-collared mule deer to estimate monthly survival rates and to investigate a variety of factors that might affect these rates including seasonal distribution, temporal effects (seasonal, annual, and trends across season and year), movement behavior, and climatic covariates on differing scales. Variation in survival rates for this population of female mule deer in eastern Oregon was best explained by an additive effect of migration behavior, fall migration period, and precipitation levels on individual winter ranges. Survival was significantly higher for migratory deer than residents. Both groups had lower survival during the fall migration period (Oct-Nov) and a positive linear relationship between survival and winter precipitation in individual winter ranges. Annual survival estimates for migrants ranged from 0.81-0.82, which is similar to other findings, but survival rates for residents (0.76- 0.77) were low in comparison to survival rates for adult female mule deer in other parts of their range. I used a nonparametric cumulative incidence function estimator (NPCIFE) to generate annual cumulative incidence functions separately for males and females due to differing risks associated with each sex. The four competing sources of mortality I included in this analysis for males were legal harvest, illegal harvest, predation, and starvation, disease, vehicle or fence-collision combined as one category (i.e., other). For females in investigated predation, human-associated mortality (vehicle or fence), illegal harvest, and natural causes (starvation and disease). Annual risk functions were pooled across all years of the study to maximize sample size. For males, the cumulative risk was highest for legal harvest (0.249, 95%CI=0.172-0.326), with predation the next highest cause of mortality for this sex (0.104, 95%CI=0.042-0.611). For females, the cumulative risk was highest for predation, (0.044, 95%CI=0.028-0.065) with anthropogenic causes (0.038, 95%CI=0.021-0.054) and illegal harvest (0.031, 95%CI=0.17-0.054) also important sources of mortality. Higher monthly survival rates of migrants compared to residents (across all months of the biological cycle) suggested that leaving for potentially higher quality summer foraging grounds outweighed the cost of traveling through unfamiliar habitats and energy expenditure from migration. Conversely, it may also imply that the summer ranges for residents had a negative effect on survival due to habitat quality or human disturbance. Both migrants and residents had lower monthly survival during the fall migration period (Oct - Nov). Female mule deer were excluded from the state-managed bow and rifle hunting season during this study, but females may experience the negative effects of human disturbance associated with fall hunting activities. This time of year is also energetically costly for females, being that some may still be nursing, which could have an additive effect to the energy used to migrate or avoid human disturbance. Winter precipitation also had positive effect on survival for both groups, possibly because increased average winter precipitation resulted in increased winter forage quantity and quality. My results suggest that female survival rates observed during my study are on the low end of the range reported for this species and may be contributing to population declines of mule deer in Oregon. Annual estimates of male survival were also low, but it is unclear how that might contribute to overall population declines without more information on annual and seasonal variation in male survival. Surprisingly, I observed high levels of illegal harvest on female deer and evidence that female survival during the fall migration period, which overlaps Oregon’s legal harvest season, was lower than other times of the year. It is unclear why the fall migration period negatively affects both migrants and resident deer similarly, but future research should attempt to determine the specific factors that are negatively impacting mule deer survival during this time period in south-central Oregon. In addition, as human development in the area continues to grow, it is important to consider migration paths and the habitat quality of both summer and winter ranges. My results suggested that conditions may differ between summer ranges in particular, for residents vs. migrants, and understanding these differences may be the key to increasing survival of female mule deer in Oregon. Sharing information from this study with law enforcement and the general public may be the first step towards increasing awareness of, and thereby reducing, the relatively high levels of illegal harvest I documented for the female population. Future research should focus on investigating the differences in habitat quality for residents versus migrants, the factors that decrease survival during fall migration for both groups, and the social and economic factors that contribute to the illegal harvest of female mule deer in eastern Oregon.
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First introduced to the USA in 1958, Myxobolus cerebralis, the parasite responsible for whirling disease in salmonids, has since spread across the country causing severe declines in wild trout populations ...
Citation Citation
- Title:
- Potential for dispersal of the non-native parasite Myxobolus cerebralis : qualitative risk assessments for the state of Alaska and the Willamette River Basin, Oregon
- Author:
- Arsan, E. Leyla
First introduced to the USA in 1958, Myxobolus cerebralis, the parasite responsible for whirling disease in salmonids, has since spread across the country causing severe declines in wild trout populations in the intermountain west. Recent development of risk assessment models used to assess the likelihood and consequences of exotic parasite introduction, have strengthened the process of science-based decision-making in aquatic animal health. In the case of M. cerebralis, it is necessary to use a risk assessment model with two unique segments that clearly address the distinct life stages and respective hosts of the parasite separately. The studies described examine the probability of M. cerebralis introduction and establishment for two regions: the state of Alaska, and the Willamette River basin, Oregon. The Alaska risk assessment was based on the assumption that the parasite did not already occur in the state. However, in the process of validating this assumption, we documented the first polymerase chain reaction (PCR) detection of the parasite in the state. The pathogen was identified in hatchery rainbow trout (Oncorhynchus mykiss) from the Anchorage area. Although this is the first detection of the parasite in Alaska, clinical whirling disease has never been documented in the state. To qualitatively assess the risk of further spread of M. cerebralis in Alaska, four potential routes of dissemination were examined: movement of fish by humans, natural dispersal (via migratory birds and stray anadromous salmon), recreational activities, and commercial seafood processing. This research indicates the most likely pathway for M. cerebralis transport in Alaska is human movement of fish. In the Willamette River basin, Oregon, introduction of M. cerebralis has already occurred, though establishment appears limited to a single private hatchery. Introduction in this region was considered the most likely to occur as a result of human movements of fish. Straying anadromous salmonids were also assessed and were present in higher numbers than predicted. However, they were not infected with the parasite, and thus the probability for introduction by this route is low. The probability of introduction of the parasite varies throughout the Willamette River basin. Areas with the highest probability for M. cerebralis introduction were identified as the Clackamas and Santiam River subbasins. The Clackamas River has already experienced an introduction of the parasite, has the largest concentration of hatcheries (state, federal, and private), has a popular sport fishery, and is the closest major tributary to the enormous piscivorous bird-populations in the Columbia River estuary. The Santiam subbasin has a popular sport fishery, received the highest number of stray fish in the Willamette River basin, and has the second largest concentration of hatcheries in the Willamette River basin. Unique from introduction, establishment of the parasite is dependent upon several environmental and biological factors including: water temperatures, spatial/temporal overlap of hosts, and the distribution and genetic composition of the parasite’s invertebrate host, Tubifex tubifex. The distribution, genetic composition and susceptibility of T. tubifex, were considered the most important factor in the ability of M. cerebralis to establish in both systems. Surveys of oligochaete populations were conducted in both study regions. In Alaska, T. tubifex was not detected from the southeast region and the apparent lack of appropriate tubificid hosts may prevent establishment in that part of the state. However, 4 lineages (I, III, IV, and VI) of the species were identified from southcentral Alaska. Lineage IV has not been previously been described in North America and its susceptibility to M. cerebralis was unknown. When lineage IV T. tubifex and 3 mixed-lineage (I, III, IV and VI) groups were exposed to M. cerebralis, only lineage III became infected under our experimental conditions. Thus, if the parasite were dispersed, conditions are appropriate for establishment and propagation of the parasite life cycle in southcentral Alaska, although detrimental effects on fish populations may be reduced as a result of the presence of non-susceptible lineages of T. tubifex. The probability of further establishment in this area is greatest in Ship Creek, where the abundance of susceptible T. tubifex, the presence of susceptible rainbow trout (Oncorhynchus mykiss), and the proximity to the known area of infection make conditions particularly appropriate. Similar to findings in Alaska, the Willamette River basin, Oregon also supports populations of susceptible T. tubifex. If the pathogen were introduced, probability of establishment is high in certain areas of the basin as all conditions are appropriate for propagation of the parasite life cycle. Tributaries to the mainstem Willamette River have the highest probability of establishment as these areas have the greatest numbers of susceptible T. tubifex. However, the abundance of resistant strains of T. tubifex could mitigate the effects of M. cerebralis if introduced. Management recommendations to reduce the likelihood of parasite dissemination are similar for Oregon and Alaska since human movement of fish and angler activities were considered the most likely routes of introduction for both regions. Based on this research, steps should also be taken to limit human movement of fish, whether by restricting carcass planting for stream enrichment in Oregon, or by prohibiting use of fish heads as bait in southcentral Alaska. The states should also allot resources to angler education and awareness of the effects of angler activity and recreation on dispersal of M. cerebralis. This could be done using a combination of brochures and signage at boat ramps describing how to prevent spread of aquatic nuisance species.
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1366. [Article] Exploring the relationship between engineering design project characteristics and risk indicators
Engineering design projects are implemented to accomplish a variety of goals in organizations. As the complexity of each project grows, the risk and uncertainty accompanying each project increases as well. ...Citation Citation
- Title:
- Exploring the relationship between engineering design project characteristics and risk indicators
- Author:
- Yim, Rachel L.
Engineering design projects are implemented to accomplish a variety of goals in organizations. As the complexity of each project grows, the risk and uncertainty accompanying each project increases as well. As a result project managers must identify potential risks to projects and create plans to avoid realized risks leading to project failures. A risk indicator is a set of circumstances that are indicative of the strong likelihood of a risk event occurring during a project. This research was created to explore the relationship between risk indicators and various project characteristics, including project classification (the type of business goals the project was created to fill) and project type (whether the project was a first or a second attempt to solve an engineering design problem). The results of this research are applicable to engineering managers who are responsible for the successful completion of design projects. The research questions addressed in this study were: 1) Is there a difference in the frequency of occurrence between the 36 risk indicator codes? 2) If there is a difference, in the risk indicator frequencies, which risk indicator codes occur most often? 3) Which risk indicator codes are the most prevalent in association with certain project characteristics? These research questions were explored with the intent of discovering the risk indicators that are most important for project managers to consider in creating risk management plans based upon project characteristics. The goal of this research is to contribute to the project management body of knowledge and to provide insight into the nature of the relationship between various project characteristics and risk indicators. To achieve this objective, eleven medium-complexity engineering design projects were selected for study. Two interview protocols were developed to elicit information about critical events occurring during the life cycles of these engineering design projects. Employees from a variety of job functions, who were directly involved in the selected projects, were interviewed. Multiple researchers coded transcripts created from the interviews. Researchers used a code scheme, developed from the literature on project success factors. The text from interview transcripts was analyzed to identify similarities and differences in the frequencies of different risk indicator codes for different project characteristics. Frequently occurring risk indicators were noted and implications for project managers were identified. The projects were divided into groups with similar project characteristics. Differences in the rates of occurrence of risk indicators were used to identify risk indicators, based on these specific project characteristics. Similarities and differences in the rates of occurrence of risk indicators in the different groups of projects were analyzed for emergent themes. The results provided strong evidence for significant differences in the frequency of occurrence for risk indicators based on project characteristics. The most frequently occurring risk indicators differed for three project classifications (strategic, compliance, and operational). The most frequently occurring risk indicators also differed for original and rework projects. Nonparametric statistical tests were also applied to the data to test between significant differences across all risk indicators, using the same project characteristics. Communication challenges were prevalent for all types of projects. Research has shown that inadequate communication can cause time and cost overruns on projects and can lead to rework projects. The types of communication challenges that were the most frequent differed between project classifications. For compliance projects, the most predominant communication risk was between the organization and suppliers. Communication risks between the organization and the customers occurred most often in operational projects. Finally in strategic projects, the most frequently occurring risks to communication occurred internally, between different business and engineering groups within the organization. Another important theme was the need for standard procedures to provide adequate documentation to the different groups involved in projects. Risks associated with a lack of information provided to the different business and engineering groups working together on projects, were common among all projects. Many interviewees suggested the need for standard procedures to provide all necessary information to all groups assigned to each project, in order to facilitate the coordination of the work. A lack of up front planning was detrimental for both original and rework projects. A lack of up front planning in original projects, at times, resulted in project failure, thereby creating the need for a rework project. In rework projects, planning at the beginning of a project was sometimes rushed due to the urgency of the project, thereby causing additional risks to the success of rework projects later on in the project life cycle. Project managers can use the findings from this research to create more effective risk management plans tailored to the characteristics of a particular project. Knowledge of the risk indicators with the highest frequency of occurrence in each type of project can direct managers to the most effective use of risk management resources. The results of this research also add to the project management body of knowledge and provide a deeper understanding of the relationship between project characteristics and specific risk factors. The results also provide evidence that the project classification and project type are important determinants of the types of risks that will likely be faced in the course of a project. The approach used for this study can be applied to other industries and other types of projects to further extend the understanding of the relationship between project characteristics and risks. While there was evidence that some risks are typical to all design projects, a larger study is needed to generalize these findings beyond design projects and beyond the engineering organization studied.
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1367. [Article] Breeding an open pollinated broccoli for organic production systems using participatory methods
Organic agriculture is an important and growing sector of U.S. and world food production. Consumers are increasingly aware of and interested in the production practices and impacts associated with agriculture ...Citation Citation
- Title:
- Breeding an open pollinated broccoli for organic production systems using participatory methods
- Author:
- McKenzie, Laurie R.
Organic agriculture is an important and growing sector of U.S. and world food production. Consumers are increasingly aware of and interested in the production practices and impacts associated with agriculture and as such, are showing a preference for sustainably produced, raised, and harvested foods. In order to continue to meet the growing demand for organic produce, organic growers need cultivars that are optimally adapted to organic and low input conditions. Quality seed is the foundation of any functional and stable farming system. Unfortunately the lack of organically bred and produced seed is hindering the continued growth and success of organic farming. Meeting the needs of the organic sector has been a challenge for the seed industry; it is an industry that often doesn't understand the specific and unique requirements associated with the diversity of environmental and market demands of organic systems. However, organic farmers and the organic food systems they supply, require a robust organic seed system that is appropriately adapted to regional agronomic challenges and market needs, meets standards and regulations, and encompasses the social and ecological values of organic agriculture. One plausible approach to meeting the cultivar and seed needs of organic and low input production systems is through the use of participatory plant breeding (PPB). PPB is a collaborative approach for identifying and developing genetically diverse plant material and varieties involving partnerships among formal sector breeders and researchers, farmers, extension agents, educators, and end users. Participatory plant breeding fundamentally changes the way that formal breeding programs and farmers manage germplasm and plant genetic resources. Typically, formal breeding programs restrict access to germplasm and breeding materials and only supply farmers with finished varieties. In PPB, farmers are involved in the early stages of creation and evaluation of germplasm and breeding material, and stay engaged with the breeding process until new varieties are created. PPB is an excellent model for breeding specifically for organic systems because organic systems in developed countries have many similarities to low-input agricultural systems in the developing world. Some of these parallels include heterogeneous growing environments, a wide range of end uses and marketing strategies, lack of suitably adapted and/or derived varieties, lack of attention from the formal seed sector, and a reduced reliance on synthetic inputs (compared to conventional systems). Breeding for organic systems is a relatively young field and breeders in the formal sector do not have a good handle on what traits are important for robust production under organic conditions. Thus the opportunity to meld farmers' experience and knowledge with breeders' expertise is an effective way to breed for organic production systems. The purpose of this project was to investigate and explore the opportunities and challenges of organic plant breeding using participatory research methods. This research had three goals: 1) to develop an open pollinated broccoli with contemporary quality traits for organic production systems using participatory strategies; 2) to compare broccoli selections made by formally trained plant breeders and farmer breeders; and 3) to capture the stories and experiences of the formal breeders and farmer breeders involved with this broccoli material in order to contribute to the growing wealth of knowledge on collaborative and organic breeding work. The Oregon State University Vegetable Breeding Program made significant progress towards decreasing the variability of the broccoli project material through three successive years of modified half-sibling selections. Evaluations and selections were based more strongly on quality traits rather than soley on production traits such as yield. Although progress was incremental and statistically verified in only three out of the fifteen quality traits, we observed trends in the data indicating progress towards an increasingly uniform, stable, and reliable open pollinated broccoli with specific adaptation for organic production systems. There were very few differences between broccoli materials developed by formally trained plant breeders and farmer breeders. This was especially true for the three cultivars developed in the Pacific Northwest (PNW) (one in Washington and two in Oregon). The 'East Coast' population, which had been collaboratively selected by formal and farmer breeders in New York, expressed significantly distinct differences from the PNW materials. When the farmer breeder and formal breeder materials were pooled together and compared to pooled check cultivars they expressed significant differences for nearly all traits across all years. This demonstrated that all of the collaboratively developed open pollinated materials are distinctly different from the F1 hybrids currently available. Our work has demonstrated a few of the myriad of positive outcomes achievable with the use of participatory plant breeding for organic production systems. The participatory nature of this project resulted in increased confidence and feelings of empowerment for all involved. Both farmers and breeders felt their involvement was socially beneficial and widened their networking and seed community circles. The farmer-bred cultivar 'Solstice' is now available as a result of Jonathan Spero's work, and a cultivar tentatively named 'Benton' is about to be released for sale through Oregon State University. Our results agree with previous study findings that formal and farmer breeder selections are often not distinctly different; thus providing evidence for continuing to support the involvement and education of farmers in plant breeding, especially in reference to organic production systems. This study demonstrates the potential of collaboratively developed and farmer-bred cultivars to become viable and vibrant open pollinated alternatives to the current open pollinated cultivars on the market today.
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The purpose of this study was to determine the readability of three series of selected fourth, fifth and sixth grade social studies textbooks, a total of nine textbooks. Two measurements were utilized: ...
Citation Citation
- Title:
- The readability of selected fourth, fifth and sixth grade social studies textbooks as determined by the Fry Readability Graph and group informal reading inventories
- Author:
- Pruitt, Janet Louise McCracken, 1930-
The purpose of this study was to determine the readability of three series of selected fourth, fifth and sixth grade social studies textbooks, a total of nine textbooks. Two measurements were utilized: a readability formula (Fry Readability Graph; Knapp, 1971), and group informal reading inventories. The Fry Graph was applied to ten randomly selected 100-word passages in each text; proper nouns were included in the computations. The group informal reading inventories were constructed from the same textbooks on passages not previously taught. The tests were administered in May to 1467 students in 70 randomly selected classrooms. Procedures Both descriptive and inferential statistics were used to analyze the data. Readability levels derived by the application of the Fry Graph were reported for each text:, as was the range of readability within each text and the deviation of each sample from the overall readability of the textbook. The test scores from the group informal reading inventories were first reported in terms of the per cent of subjects scoring at the independent level (90, 95, 100 per cent), the instructional level (65, 70, 75, 80, 85 per cent) and the frustration level (60 per cent or lower) for the sample. Mean test scores were also computed for the sample, the urban and rural subsets, for each grade level, and for each publisher. To determine if there were significant differences among the subsets, the following null hypotheses were formulated: H1 There are no significant differences in the mean scores of the urban and rural subjects. H2 There are no significant differences in the mean scores of the subjects in grades four, five and six. H3 There are no significant differences among the mean scores of the subjects tested on the D. C. Heath, the Silver Burdett or the Benefic Press social studies series. The differences among groups were statistically analyzed at the .05 and .01 levels of significance by the pooled variance t-test or by the analysis of variance. When the analysis of variance resulted in a significant F value, the multiple range test was applied to determine the exact location of the mean difference. Findings of the Study Fry Readability Graph 1. Two textbooks, the fourth grade textbooks published by D. C. Heath and by Silver Burdett, had readability levels in agreement with the publishers' designated grade level. The remaining seven textbooks had readability levels one to four years above the designated grade level. 2. The average range of readability within the textbooks was 6.2 years with little evidence of a gradation from less difficult to more difficult reading material. 3. When the three series were ranked according to their relative difficulty on the basis of the Fry readability levels, it was determined that: a. The D. C. Heath series is the least difficult. b. The Silver Burdett series occupies an intermediate position. c. The Benefic Press series is the most difficult. Group Informal Reading Inventories 1. For the total sample 9.41 per cent of the subjects scored at the independent level, 32.04 per cent scored at the instructional level, and 58.55 per cent scored at the frustration level. The mean test score was 54.82 per cent. 2. The mean score (56.64 per cent) of the urban subjects was significantly higher (.01 level) than the mean score (52.35 per cent) of the rural subjects with a t value of 3.30. H1 was rejected. 3. The mean score for grade four was 50.35 per cent; for grade five, 53.96 per cent; and for grade six, 58.09 per cent. The analysis of variance resulted in a significant (.01 level) F value of 11.25. H2 was rejected. 4. The mean scores by publisher were: D. C. Heath, 55.88 per cent; Silver Burdett, 55.77 per cent; and Benefic Press, 50.38 per cent. The analysis of variance resulted in a significant (.01 level) F value of 5.47. The multiple range test showed significant differences between the Benefic Press and D. C. Heath series (.01 level) and between the Benefic Press and Silver Burdett series (.01 level). There were no significant differences between the D. C. Heath and Silver Burdett series. H3 was rejected. Implications 1. The findings of this study did not differ in any substantial way from the results reported by earlier investigators. Further studies of the readability of social studies textbooks similar in content to the three series analyzed in this investigation is not warranted. 2. Additional research is needed to determine if systematic instruction resembling the procedures prescribed for a well-developed basal reading lesson will significantly affect the ability of students to comprehend social studies textbooks. Recommendations 1. Current knowledge regarding the nature of concept development should be a major consideration for curriculum decisions in the social studies. Piaget's findings regarding the cognitive functioning of elementary school students provide insight regarding the capabilities of this age group. 2. Instructional alternatives that diminish heavy reliance on the textbook should be afforded a fair trial in the classroom, e.g., simulation and gaming (Cuetzkow, 1962; Inbar, 1972), process analog (Fielder, 1967; Joyce, 1972), role playing (Shaftel, 1967), problem solving (Fenton, 1967; Shaftel, 1967), inquiry approaches (Suchman, 1964; Clements, Fielder, Tabachnick, 1966), and inductive development of concepts and generalizations (Taba, 1966; Fenton, 1966; Hanna, 1965). 3. A publicly financed agency staffed by expert analysts and equipped with the necessary resources should be established to provide analysis services to publishers and to determine the difficulty level of all instructional materials as they appear on the market (Bormuth, 1971). 4. Pilot editions of all new textbooks should be field tested with a cross section of students using procedures similar to those utilized by the publishers of standardized tests. 5. When classroom teachers make reading assignments in social studies textbooks, they should faithfully adhere to the same procedures that are prescribed for a well-developed basal reading lesson.
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Because many coral-reef fishes are observable in situ, are amenable to transplantation, have small home ranges and short generation times, they provide a excellent system to investigate many topics within ...
Citation Citation
- Title:
- Coral-reef fishes : insights into larval dispersal and invasion ecology
- Author:
- Pusack, Timothy J.
Because many coral-reef fishes are observable in situ, are amenable to transplantation, have small home ranges and short generation times, they provide a excellent system to investigate many topics within general ecology, fisheries biology, and conservation biology. The primary goal of this dissertation was to use the coral-reef fishes system to investigate two pressing sets of issues that face marine ecologists and managers of living marine resources. The first topic is the spatial and temporal patterns of larval dispersal and reproductive success in a marine metapopulation (Chapter 2). Because miniscule larvae are difficult to track in the vast pelagic environment, little is known about the patterns of larval dispersal. Yet, the more that is understood about the spatial and temporal variability in larval dispersal, the easier it will be to identify sites that are self-sustaining and exporting larvae to unprotect sites, a common goal of marine reserves. Incorporating this information into siting of marine reserves will improve their effectiveness. The second topic is fundamental in the ecology of biological invasions: species specific interactions between an invasive predator and native species. Specifically, I investigated the ability of an invasive predator to disrupt natural population regulation of a native prey species (Chapter 3), and the ability of a native predator to provide biotic resistance against the invasive species (Chapter 4). Because management of the lionfish invasion is needed throughout the Caribbean and Atlantic waters, it is necessary to understand not only how lionfish can change the native system, but also potential ways to moderate the negative effects. To address the first topic, we collected a total of 3,278 genetic tissue samples from bicolor damselfish (Stegastes partitus) over a four year period from reefs near four islands that encompass Exuma Sound, Bahamas (Chapter 2). Using a Bayesian parentage analysis, eight parent-offspring pairs were detected, which directly documented both connectivity between and self-recruitment on an ecological time scale. Remarkably, some larvae returned to the exact same reef where they were spawned, while others traveled to sites greater than 100 km distance. The only study island without a detected parent-offspring pair, Lee Stocking Island, was also the island that showed the most restrictive gene flow on evolutionary time scales. Additionally, variability was documented in the spatial and temporal signatures of sweepstakes reproduction and Wahlund effects. The variation we observed may be influenced by seasonal mesoscale gyres present in Exuma Sound, which play a prominent role in shaping local oceanographic patterns. Understanding how to identify pathways of larval dispersal is important to designing networks of marine reserves, because a common goal of reserves is to protect populations that are self-seeding and can export larvae. Thus, this research not only demonstrates that temporal variability is a prominent characteristic of larval dispersal, but provides an example of how to identify these populations. To address the second topic, two studies using both lab observations and manipulative field experiments were conducted to study the interaction between invasive Indo-Pacific red lionfish (Pterois volitans) and two different native species. In the first study (Chapter 3) three different data sets were used to document the effect of lionfish predation on their top prey species, the bridled goby (Coryphopterus glaucofraenum). The first data set was extracted from three previous studies to compare the change in abundance of bridled goby between patch reefs with lionfish and patch reefs that were predator-free. The second data set came from laboratory feeding trials to test for the presence of a size refuge for bridled goby caused by lionfish gape limitation. The third data set came from a manipulative field experiment using 22 nearshore reefs where the per capita mortality of bridled gobies was compared among four orthogonal predator treatments: (1) predator-free control, (2) a single native predator only -- the graysby grouper (Cephalopholis cruentatus) -- representing the pre-invasion system, (3) a single lionfish only, and (4) one native grouper and one lionfish, representing the invaded system. The combined results from these three data sets demonstrated that lionfish can consistently consume a significant amount and an extremely high proportion of bridled goby on small patch reefs. While small lionfish cannot eat bridled goby larger than 0.42 times their body size, large lionfish eat virtually the entire size range of bridled goby. These findings indicate that lionfish have the potential to extirpate local goby populations. In the second experiment, lionfish were exposed to different abundances of a native grouper, the Nassau grouper (Epinephelus striatus), on 28 nearshore patch reefs in the Bahamas. Lionfish persistence and growth was monitored over 10 weeks, as well as the abundance of small, < 5 cm total length (TL), native reef fishes. Nassau grouper did not affect lionfish persistence or growth. Yet, reefs with a lionfish and many Nassau grouper saw a significant increase in the abundance of small reef fishes compared to reefs with only lionfish or lionfish with few grouper. Thus, it appears that high densities of Nassau grouper provide some biotic resistance on Bahamian patch reefs by potentially interfering with lionfish predation on native fishes, perhaps by interrupting stalking behavior. This dissertation highlights the flexibility of the coral-reef fishes system for investigation of broadly different topics in basic and applied ecology. Coral-reef fishes are a tractable system for both large and small scale studies, as well as laboratory observations and manipulative field experiments. The findings of this dissertation advance the understanding of metapopulation dynamics and have implications for fisheries management and marine reserve design. This research also documents further evidence of the negative effects of lionfish, yet provides some promising findings that may indicate some native biotic resistance to this devastating of marine invasions.
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Eight Tertiary sedimentary and volcanic units crop out in the thesis area. From oldest to youngest they are the: Sager Creek formation (informal); Pittsburg Bluff Formation; Northrup Creek formation (informal); ...
Citation Citation
- Title:
- The geology of the Elk Mountain-Porter Ridge area, Clatsop County, northwest Oregon
- Author:
- Goalen, Jeffrey Scott
Eight Tertiary sedimentary and volcanic units crop out in the thesis area. From oldest to youngest they are the: Sager Creek formation (informal); Pittsburg Bluff Formation; Northrup Creek formation (informal); Smuggler Cove formation (informal); Wickiup Mountain and Cannon Beach members (both informal) of the Astoria Formation; the Grande Ronde Basalt, and Frenchman Springs Member of the Wanapum Basalt, both of the Columbia River Basalt Group. Also, areally limited, unnamed sedimentary strata interbedded between flows of the Columbia River Basalt Group crop out in the study area. Quaternary deposits consist of alluvium, colluvium, and landslide debris. Rhythmically-bedded, foram-bearing, carbonaceous to micaceous mudstone and graded, fine-grained, feldspathic turbidite sandstone are the dominant lithologies of the upper Eocene (Refugian) Sager Creek formation. Plane-laminae and climbing ripple-laminae typical of Bouma b,c, and d intervals are common in the thin turbidite sandstone beds. Contemporaneous, rare, thick, sandstones may represent submarine feeder channels that supplied the more widespread, thinly-bedded overbank turbidite sandstones. Foraminiferal paleobathymetry indicates that deposition was in bathyal water depths. Sager Creek deposition was followed by a regression or offlap of the late Eocene to early Oligocene (Refugian) sea as indicated by the molluscan fossils and thick, bioturbated sandstone of the predominantly shallow-marine Pittsburg Bluff Formation. The lower part of the formation consists of outer shelf, glauconitic, fossiliferous sandstone and subordinate mudstone. Higher in the section are middle-shelf, fine-grained, bioturbated, tuffaceous, arkosic sandstones. These sandstones contain minor glauconite, wave- and storm-generated molluscan shell hash beds, carbonized wood fragments, and calcareous concretions. Deposition occurred in 20 - 50 m open-marine shelf water depths; however, the depositional environment may have shallowed to a bay-like setting (Moore, 1982, written communication). The upper part of the unit consists of thin- to medium-bedded, carbonaceous siltstone and mudstone with minor ashfall tuffs. Therefore, deposition of the Pittsburg Bluff Formation occurred as a shallowing-upward, then deepening depositional episode, punctuated by contemporaneous, intermittent eruption of nearby calc-alkaline western Cascade volcanoes. The deep-marine Oligocene to lower Miocene (Zemorrian to Saucesian) Northrup Creek formation is predominantly composed of thinly-laminated mudstone interbedded with thin, very fine-grained, graded, micaceous arkosic sandstone. Bouma c-d-e and a-b-e sequences are common in the turbidite sandstone; Bouma a-e intervals occur locally in sandstone/mudstone couplets. Paleocurrent indicators suggest that the predominant transport direction of these turbidite deposits was northeast to southwest. Abraded, carbonaceous plant debris and mica are abundant in the sandstone laminations. The upper part of the formation consists of thick, mollusk-bearing, moderately- to well-sorted, arkosic sandstone and minor polymict grit beds. A shallowing-upward, high-energy, shallow-marine shelf environment of deposition is indicated for the upper part of the formation. Contemporaneous with shelf and slope deposition of the Sager Creek, Pittsburg Bluff and Northrup Creek formations, the deep-water late Eocene to early Miocene Smuggler Cove formation was deposited as a distal or lateral correlative in a low-energy, outer shelf to slope setting. This foram-bearing unit consists of thick, bioturbated, bathyal, tuffaceous mudstone and siltstone with minor thin- to thick-bedded ashfall and current-reworked tuff. A marine onlap is indicated by the conformable relationship between the upper sandstone unit of the Northrup Creek formation and the overlying Smuggler Cove formation in the eastern part of the thesis area. The overlying lower to middle Miocene Astoria Formation contains two members in the thesis area: a high-energy, shallow shelf, fine- to medium-grained, fossiliferous, micaceous arkosic sandstone (Wickiup Mountain member), and an overlying, thinly-laminated, deepmarine mudstone (Cannon Beach member). Diatom floras indicate that a thermal "oceanographic irregularity" (water warmer than normal) may have occurred during deposition of the Cannon Beach member. At least six, and possibly eight, flows of the middle Miocene Grande Ronde Basalt (Columbia River Basalt Group) are present in the thesis area. Individual flows have been ascribed to the (N1?), R2, and N2 magnetozones. Geochemically, the flows consist of low MgO high Ti02, low MgO low Ti02, and high MgO subtypes. These subaerial to submarine flows are correlated to Mangan and others (1986) chemical subtypes 2D, 5C, 5A, and 4A of the Columbia Plateau-derived Grande Ronde Basalt of eastern Washington and eastern Oregon. The correlations are based on similarity of age, major element chemistry, stratigraphic position, and magnetic polarity. Field evidence suggests that thick, submarine pillow and breccia complexes generated sufficient pressure to autoinvasively inject into the Eocene to middle Miocene sedimentary strata of the Plympton/Porter ridge and Elk Mountain areas. This process apparently formed many randomly-oriented dike- and sill-like intrusions in the western part of the thesis area. However, in the eastern and central parts of the thesis area, three sub-parallel dikes (the Northrup, Beneke, and Fishhawk Falls dikes) extend along linear trends for tens of kilometers. This suggests that their emplacement was, in part, influenced by earlier or contemporaneous regional tectonism. At least two, and as many as five, flows of the Frenchman Springs Member of the Wanapum Basalt occur in the thesis area: one to two abundantly plagioclase-phyric Basalt of Ginkgo flow(s), and one to three Basalt of Sand Hollow flows (terminology after Beeson and Tolan, 1985). These flows consist of subaqueous pillow palagonite breccia and vesicular, columnar-jointed, subaerial basalt. No Frenchman Springs flows are invasive in the thesis area. Local middle Miocene sedimentary interbeds between flows of Grande Ronde and Frenchman Springs Basalt are lithologically and sedimentologically diverse. Common lithologies are fine- to mediumgrained, arkosic sandstone, coarse-grained basaltic sandstone, and structureless mudstone. Depositional environments represented by these strata are fluvial, marginal-marine, and shallow-marine. Thicknesses of individual interbeds range from 0.2 to 50 m. The thesis area is located on the northwest flank of the Oregon Coast Range anticline, adjacent to the Nehalem Arch. Large-scale northeast-trending oblique to strike-slip left-lateral faults coupled with northwest-trending oblique to strike-slip right-lateral faults dominate the structure of the area. These faults may have formed as conjugate shears (Riedel shear) caused by north-south compressive stress related to the oblique subduction of the Juan de Fuca Plate beneath the North American Plate. Five episodes of deformation are suggested by faults, dike orientations, unconformities, and other geological relationships within the thesis area: a late Eocene north-south compressional episode, an early Oligocene to early Miocene uplift, a middle Miocene northwest-southeast extensional episode, a post-middle Miocene to Pliocene (?) north-south compressional episode, and a north-south extensional event that occurred between the post-middle Miocene and Recent. Although crushed rock (for road and revetment construction) is currently the primary mineral resource within the thesis area, several potential fault traps on this northwest flank of the Nehalem Arch may contain significant reserves of natural gas. This conclusion is based upon field, laboratory, and subsurface (well) data. The Clark and Wilson sandstone of the middle to late Eocene Cowlitz Formation, the producing unit at the nearby Mist gas field, represents the most attractive target horizon. Additionally, the porous and permeable upper sandstone unit of the Northrup Creek formation could contain shallow hydrocarbon reserves beneath the northern part of the area.