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Assessment of perennial bioenergy buffers within a row crop production system
Get PDFModern agricultural production systems face a major challenge today. While producing large amounts of food, energy, and bioproducts, these systems need to be managed to achieve long-term sustainability (e.g. crop productivity potential) and minimal downstream effects (e.g. externalities such as eutrophication and hypoxia). One approach to addressing these challenges is through the development and implementation of multifunctional landscape designs which can be used to achieve different, yet related goals, such as crop production and reduction of negative environmental impacts (e.g. water quality, biodiversity loss, greenhouse gas emissions, and declining soil health). One component of multifunctional landscape design in annual row crop production is the integration of perennial bioenergy crops on marginal lands (buffers, filter strips, shelter belts, etc.) which has the potential to provide alternative crop revenues and increase environmental and societal benefits through the provision of ecosystem services. However, the benefits of perennial bioenergy crops may vary by crop types, cropping systems, management practices, and field landscapes; therefore, more field research is needed to understand the influence of these factors. The studies presented in this dissertation determined the impacts of crop management, crop type, and landscape design on ecosystem service potential and biomass productivity of perennial bioenergy crops produced on marginal agricultural lands in Illinois, USA. The first 9-year study (2011-present) evaluated the impacts of strategically placed short-rotation shrub willow (Salix miyabeana ‘SX61’) buffers in a corn-soybean field in central Illinois on nutrient loss reduction and recovery, greenhouse gas emissions, soil health, and biodiversity (invertebrate, plant, and soil microbial). Willows were found to significantly reduce nitrate-nitrogen loss from the neighboring grain cropping system, as well as reduce nitrous oxide emissions, increase soil organic matter, and provide habitat for unique microorganisms, plants and important invertebrate functional groups such as pollinators and predators. The position of the buffers within the agricultural field was also important for the provision of some of these services and for enhanced biomass production. The second study focuses on the impact of nitrogen fertility and harvest management on feedstock productivity of several perennial warm-season grass species and cultivars (switchgrass, Miscanthus x giganteus, and perennial grass mixtures) on a wet marginal land. The study found Miscanthus x giganteus produced the greatest amount of biomass of the feedstocks compared. However, harvest timing (summer versus after a killing frost) was found to be the largest factor influencing sustainable biomass production as compared to nitrogen (N) fertilizer application. Overall, the results of these studies show the potential benefits of producing perennial bioenergy crops on marginal land; however, they also highlight the importance of considering management, crop type, and landscape design in the production of perennial bioenergy crops as they can influence both crop productivity as well as the provision of ecosystem services.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2022-05-01The student, Colleen Zumpf, accepted the attached license on 2020-01-31 at 09:25.The student, Colleen Zumpf, submitted this Dissertation for approval on 2020-01-31 at 09:42.This Dissertation was approved for publication on 2020-01-31 at 10:24.DSpace SAF Submission Ingestion Package generated from Vireo submission #14864 on 2020-08-25 at 17:38:31Made available in DSpace on 2020-08-27T00:46:48Z (GMT). No. of bitstreams: 3
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Effects of Management Practices on Grassland Plant and Bird Community Composition in Kane County Forest Preserves
Get PDFLoss of grassland ecosystems over the past century has increased importance of efforts to improve and restore habitat for native plant species and the biotic communities they support. As a result of these efforts, biotic and abiotic conditions and interactions with the environment are altered. Species evolution based on these particular environmental conditions has caused many species to be mapped onto various environmental gradients which can be defined as niche separation. This study attempted to determine what environmental gradients had the strongest impact upon grassland bird and plant species niche separation, particularly those gradients defined by management activities such as burning, chemical maintenance, and mechanical maintenance of forbs and brush. The main hypothesis tested was that abundance of grassland bird and plant species will be positively related to the increase in frequency of maintenance events including burn, chemical, and mechanical maintenance. The related sub-hypothesis is that bird and plant communities will also respond to other abiotic and biotic factors or characteristics of the sampling units. In 45 sampling units within 9 forest preserves in Kane County, IL. Plant species percent cover, bird species abundance, soil moisture, and vegetation structure were measured. Data including burn regime, chemical and mechanical maintenance, grassland age, and seeding/planting frequencies were obtained from the Forest Preserve District of Kane County. Other variables analyzed including percent fragmentation, grassland size, and proportion of neighboring habitat type (forest, wetland, and shrubland) or land use (developed or agriculture) were determined using ArcMap. Eighteen environmental/management factors were analyzed against 156 plant species and 42 bird species across the 45 sampling units using canonical correspondence analysis (CCA). CCA axes explained 45.1% and 51.5% of total variation in plant and bird species distributions, respectively. This study’s two hypotheses were partially supported because both grassland plant and bird species responded positively to mechanical maintenance of brush and forbs, prescribed burning, and other environmental factors. Top environmental/management factors that influenced plant species distribution were hours of mechanical forb maintenance; followed by proportion of neighboring forest, wetland, and shrubland within a 400m radius; hours of mechanical brush maintenance; vegetation height; and grassland size within a 200m radius. Top factors that influenced bird species distribution were soil moisture followed by grassland size within both 200m and 400m radii, percent fragmentation both 200m and 400m radii, hours of mechanical forb maintenance, and proportion of neighboring agriculture cover within a 400m radius. Ten factors, three of which were maintenance activities, influenced both plant and bird species distributions. Results of both plant and bird species CCAs suggest that there is no single dominating environmental gradient that influences distribution. Moreover, additional environmental factors not included in this study may influence both grassland plant and bird species distributions. This study highlights the importance of conducting observational analyses on management sites to determine what major factors influence species presence and how management decisions can best be used to have the largest benefit upon the community as a whole
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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