1,721,001 research outputs found
Effects of Landscape Position on Perennial Biomass and Food Crop Performance in Buffer Areas
No full textFiles contain all data collected over a 2-year period at two locations in Minnesota.Due to the environmental consequences of annual-dominated cropping systems, there is an increasing need to identify agronomic strategies which incorporate perennial crops. One strategy for increasing perennial cover is through the targeted use of annually-harvested perennial food and bioproducts crops in buffer strips, which has the potential to create new revenue streams for farmers and substantially mitigate agricultural nutrient pollution from conventional cropping systems. As buffers are typically installed on marginal land, it is critical to understand how landscape position influences the success of perennial crops. The objectives in this study were to determine the relatively early influence of landscape position on the productivity of a variety of perennial crops and their subsequent soil nutrients and soil water storing capabilities. In this experiment, nine perennial (alfalfa, alsike clover, indiangrass, switchgrass, big bluestem, prairie cordgrass, intermediate wheatgrass, high diversity polyculture, low diversity polyculture) and two annual (corn, soybean) crops were planted across two landscape positions (hillslope and deposition). Plant biomass, plant tissue nitrogen, soil moisture, and soil NO3-N and NH4-N were measured and compared at two different locations in Minnesota. Overall, the polyculture mixes, and to some extent intermediate wheatgrass, performed the best with respect to biomass production while also providing ecosystem services across most soil by landscape position combinations tested in this study. However, there were some important findings specific to each soil and landscape position combination, mainly oriented towards biomass production. We also observed temporal patterns in soil moisture and depth-related patterns in soil N reductions. This study presents an opportunity to optimize the use of perennial crops on marginal agricultural lands for improved environmental and economic benefit.Minnesota Soybean Research & Promotion Council, project 30-5030-18-06.Black, Katie, L.; Johnson, Gregg, A; Samantha, Wells, S.; Garcia y Garcia, Axel; Jungers, Jacob, M.; Jeffrey, Strock, S.. (2024). Effects of Landscape Position on Perennial Biomass and Food Crop Performance in Buffer Areas. Retrieved from the Data Repository for the University of Minnesota (DRUM), https://doi.org/10.13020/52cc-k949
Data and Codebook for "Constructing a New Measure of Macropartisanship Disaggregated by Race and Ethnicity"
No full textContains macropartisanship data disaggregated by race and ethnicity. The data will be updated each summer around July 1st
Effects of Landscape Position on Perennial Biomass and Food Crop Performance in Buffer Areas
No full textBlack, Katie L.; Johnson, Gregg A; Jungers, Jacob M.; Garcia y Garcia, Axel; Strock, Jeffrey S.; Garcia y Garcia, Axel; Wells, Samantha. (2022). Effects of Landscape Position on Perennial Biomass and Food Crop Performance in Buffer Areas. Retrieved from the University Digital Conservancy, https://doi.org/10.13020/w3hn-gp06
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
Biological Control of Canada Thistle in Wetland Prairie Restoration
No full textPseudomonas syringae pv. tagetis (Pst), a phytopathogenic bacterium, was evaluated as natural biological control agent for Canada thistle [Cirsium arvense (L.) Scop.]. Canada thistle patches exhibiting symptoms of Pst infection commonly occur along roadsides in association with perennial grasses and a grass litter layer. Field experiments were conducted to determine if grass and litter provide an environment that supports Pst infection of Canada thistle or if grass, litter, and soil collected from infected Canada thistle patches act as inoculum sources for Pst infection of Canada thistle. This experiment provides evidence that grass and litter are important components of the landscape that support the natural Pst infection of Canada thistle, and perennial grass competition has potential to manage Canada thistle in roadside rights-of-way and wetland restoration sites. A previously published Pst specific primer set was determined to require high Pst populations for detection.Minnesota Department of TransportationEichstaedt, Kari; Wyse, Donald; Johnson, Gregg. (2007). Biological Control of Canada Thistle in Wetland Prairie Restoration. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/5592
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
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