2,239 research outputs found
Occurrence, abundance, and associations of Topeka Shiners and species of greatest conservation need in streams and oxbows of Iowa and Minnesota
Since settlement, the landscape of the Midwestern United States has undergone many changes. In Iowa and southern Minnesota, approximately 70-80% of land is in agricultural production. Agricultural practices often involve substantial modifications to existing streams. Many streams in Iowa and southern Minnesota have been channelized to aid in removal of excess water from crop fields. Channelization results in not only more homogenous habitat in the stream channel, but also leads to less connectivity between the stream and its floodplain. Many fish species have evolved to prefer particular habitat features, such as riffles, pools, and off-channel habitat. Because these habitats are often removed or made less accessible through channelization, populations of many native stream fishes in Iowa and Minnesota have declined over several decades. The Topeka Shiner (Notropis topeka) is the only fish that is federally listed as endangered in the interior streams of Iowa and Minnesota. About two decades ago, Topeka Shiners were found to commonly persist in oxbows. As a result, several agencies are now involved in restoring oxbows that have filled with sediment over time to improve habitat for Topeka Shiners and a range of other fishes and terrestrial wildlife. However, a greater understanding of what characteristics of restored and unrestored oxbows influence the presence of Topeka Shiners is needed. Furthermore, Topeka Shiners and other species of conservation need can only populate oxbows if they first are present in the adjacent stream channel. Thus, a greater understanding of characteristics that influence the presence of several of Iowa and Minnesota’s rare fish species in streams is needed.
I used electrofishing and seining to sample fish assemblages at stream sites, whereas I only used bag seines to sample the fish assemblage at oxbow sites. At each site, I also measured dozens of potentially influential abiotic (habitat and water quality) characteristics. Examining streams and oxbows separately, I then used nonmetric multidimensional scaling and logistic regression models to determine which predictor variables were most important for the presence of Topeka Shiners and other species of greatest conservation need (SGCN). In 2016-2017, 111 stream sites and 98 oxbows were sampled in the Boone River, Beaver Creek, North Raccoon River, and Rock River watersheds. Topeka Shiners were present at 40 stream sites and 13 SGCN were sampled but only six were common enough (present at 20-67% of sites) to include in statistical modeling. The presence of four of six SGCN was positively associated with species richness, and three species were associated with either wetted width and/or gravel substrate. In general, important variables for predicting species presence in streams varied across models and species. Topeka Shiners were present at 40 oxbows, being sampled more often and with a higher average relative abundance in restored oxbows compared to unrestored oxbows. Logistic regression models indicated that Topeka Shiner presence was positively associated with species richness, Brassy Minnow Catch Per Unit Effort (CPUE), Orangespotted Sunfish CPUE, dissolved oxygen, and turbidity in an oxbow, while also being negatively associated with oxbow wetted length. The results of this project add to our understanding of associations of rare fish species and will be used to help guide the restoration process for Topeka Shiners and other SGCN
Identification Of Differences Between Information Communicated By Text Messaging And Voice Message On Feedback
This study examined the modifying effect of communication via voice or text on a cellular phone as it relates to the effects of feedback on future performance, self-efficacy, and perceived face validity. Previous literature has established an effect of positive feedback enhancing future performance and self-efficacy, and negative feedback decreasing future performance and self-efficacy, but no research currently exists on how this effect can be modified by method of delivery over cellular phone. This study examined the effect of positive and negative feedback by having participants complete self-efficacy, face validity, and performance measures. The participants then received positive or negative feedback via voice or text message on their cellular phones, and then completed a second set of measures. The results of this study did not find the expected base effect of positive and negative feedback, and showed that the forms used by participants had significantly different results. However, using a method to center scores, it was found that receiving feedback by voice significantly increased future performance when feedback was positive, and decreased when feedback was negative, in comparison to receiving the feedback by text. Future research should seek to further validate the results of this study by replicating the findings using equivalent forms. It should also look at demographic factors in relation to this study\u27s findings
Testing the waters: a spatial analysis of an engineered water management system at Angamuco, Michoacán, Mexico
2019 Fall.Includes bibliographical references.The prehistoric Purépecha site of Angamuco is located on the eastern edge of the Lake Pátzcuaro Basin in Michoacán, Mexico, the geopolitical core of the Late Postclassic Purépecha Empire. The site is situated on an ancient volcanic lava flow known as a malpais with no nearby sources of perennial surface water to support the large population present. The region's climate is marked by a wet and dry cycle, wherein 80% of the precipitation received by the basin falls between the months of May through August. This thesis attempts to delineate the natural hydrology of the landscape at Angamuco and to identify and quantify the water management system engineered by the inhabitants of the site to retain surface runoff throughout the course of the annual dry season. Using LiDAR data acquired for Angamuco and algorithmic tools in ESRI ArcMap 10.6, the hydrology of the site can be visualized in order to extract and quantify the spatial and volumetric characteristics of the reservoirs at the site. By combining the volumetric reservoir data, hydrologic data, and climatic data for the region, a more dynamic picture of prehistoric water management begins to emerge. The analysis of these datasets provides evidence that the landscape at Angamuco was modified to optimize water retention at specific locations and that the water retention features are of adequate size and volumetric capacity to sustain a large population over the course of the dry season. Additional field research might greatly supplement the data presented here to provide a clearer picture of the complex water management strategies of the prehistoric inhabitants of Angamuco
A capabilities approach to environmental assessment: enhancing the integration of human development and well-being in participatory environmental decision making
Building on the work of Martha Nussbaum and Amartya Sen, this research aims to enhance integration of human development and well-being in environmental assessment through developing a capabilities approach to the practice. The research emphasises the effectiveness and equity imperatives of public participation and highlights the inclusion of appropriate social considerations in environmental decision making. The participatory focus emphasises the potential for decision shaping by stakeholders and decision support for stakeholders to participate meaningfully in environmental assessment. The research develops an evaluative framework for public participation that better considers the capabilities of stakeholders. It explores the potential consilience of the capabilities approach and that of environmental assessment, with emphasis on the principles of justice in participatory decision making. A mixed methods approach explores, tests and evaluates a selection of five South African environmental assessment case studies using an applied capabilities framework. Four main methods are employed, a discourse analysis of environmental assessment reports, a conventional Q methodology, an adapted ranking Q methodology, and a survey using Likert scales. The research findings highlight the relationship between the stakeholder's capability considerations that relate to aspects of their 'ability', 'opportunity' and 'constraints' to participation. The research ranks an array of capabilities and provides insight into the types of capabilities stakeholders value highly when reflecting on their participation experience in environmental decision making. Reflecting on the emergent findings from the cases, the research contributes to the praxis of environmental assessment through theoretical development. The theoretical framework focuses on an individual's participation capabilities as well as a broader consideration of capabilities for practice to increase the realizable opportunities, or freedoms, to choose the kinds of environmental futures that can reasonably be considered as valuable and sustainable. Capability concepts of 'ceilings', 'thresholds' and 'capability sufficiency' are commended as supplementary to existing practice specifications of 'meaningful' participation. The research commends that the capabilities approach has potential to be included as a core part of the training for assessment practitioners. It also concludes that the field of environmental assessment provides a rich empirical context for the development of a more robust sustainability-orientated capabilities approach
Absolute tumor perfusion determined by nuclear magnetic resonance spectroscopy :
The ultimate goal of this dissertation is to describe the optimization and implementation of an NMR indicator uptake technique which can non-invasively and repeatedly measure tissue perfusion. Chapter II concerns itself with the method optimization of the NMR approaches to measuring tissue perfusion. Since the primary goal of this dissertation research is to obtain absolute perfusion measures, and the AIF is required for this, Chapter II discusses the development of the apparatus and NMR method with which one can extract an apparent AIF from individual rats - a method which will not necessarily result in the animal\u27s immediate death. As a further extension of this goal, research was performed to determine the feasibility of eliminating the need for individual AIF measurement by constructing a common AIF from a small set of animals, and then of using this derived common AIF for all subsequent animals within a study. Chapter II also describes results of computer simulations performed to assess the impact which tissue perfusional heterogeneity, indicator SIN within the tissue sample, and variations in the AIF have on determining absolute perfusion with the two methods of data analysis used with the NMR uptake approach. In Chapter III, a modified uptake approach is introduced (developed as a consequence of the results of the research performed in Chapter II) which uses a common AIF and a bolus indicator dose, as well as optimized data analysis. This modified uptake approach is tested against a commonly used method (which does not require knowledge of an AIF in measuring absolute tissue perfusion. The comparison was done by designing apparatus and developing techniques which allowed the simultaneous performance of whole-volume average perfusion measurements of a rat tumor model with both the modified NMR uptake method and the commonly used microsphere approach. Finally, Chapter IV summarizes the dissertation experiments performed, and briefly comments on the significance of this research
Notes and Discussion Piece: Status of the Topeka Shiner in Iowa
The Topeka shiner Notropis topeka is native to Iowa, Kansas, Minnesota, Missouri, Nebraska, and South Dakota and has been federally listed as endangered since 1998. Our goals were to determine the present distribution and qualitative status of Topeka shiners throughout its current range in Iowa and characterize the extent of decline in relation to its historic distribution. We compared the current (2016–2017) distribution to distributions portrayed in three earlier time periods. In 2016–2017 Topeka shiners were found in 12 of 20 HUC10 watersheds where they occurred historically. Their status was classified as stable in 21% of the HUC10 watersheds, possibly stable in 25%, possibly recovering in 8%, at risk in 33%, and possibly extirpated in 13% of the watersheds. The increasing trend in percent decline evident in earlier time periods reversed, going from 68% in 2010–11 to 40% in the most recent surveys. Following decades of decline, the status of Topeka shiners in Iowa appears to be improving. One potential reason for the reversal in the distributional decline of Topeka shiners in Iowa is the increasing number of oxbow restorations. Until a standardized monitoring program is established for Iowa, periodic status assessments such as this will be necessary to chronicle progress toward conserving this endangered fish species
QoE-aware inter-stream synchronization in open N-screens cloud
The growing popularity and increasing performance of mobile devices is transforming the way in which media can be consumed, from single device playback to orchestrated multi-stream experiences across multiple devices. One of the biggest challenges in realizing such immersive media experience is the dynamic management of synchronicity between associated media streams. This is further complicated by the faceted aspects of user perception and heterogeneity of user devices and networks. This paper introduces a QoE-aware open inter-stream media synchronization framework (IMSync). IMSync employs efficient monitoring and control mechanisms, as well as a bespoke QoE impact model derived from subjective user experiments. Given a current lag, IMSync's aim is to use the impact model to determine a good catch-up strategy that minimizes detrimental impact on QoE. The impact model balances the accumulative impact of re-synchronization processes and the degree of non-synchronicity to ensure the QoE. Experimental results verify the run-time performance of the framework as a foundation for immersive media experience in open N-Screens cloud
SEDP-2014-05
In this study we elicit agents' prior information set regarding a public good, exogenously give information treatments to survey respondents and subsequently elicit willingness to pay for the good and posterior information sets. The design of this field experiment allows us to perform theoretically motivated hypothesis testing between different updating rules: non-informative updating, Bayesian updating, and incomplete updating. We find causal evidence that agents imperfectly update their information sets. We also field causal evidence that the amount of additional information provided to subjects relative to their pre-existing information levels can affect stated WTP in ways consistent overload from too much learning. This result raises important (though familiar) issues for the use of stated preference methods in policy analysis
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