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TOSS: A topology-based scheduler for storm c1usters
No full text© 2020 IEEE. Nowadays, our world is undergoing profound challenges in processing a massive amount of data. A handful of computation technologies emerge as a promising computation platform for data intensive processing. Apache Storm is an outstanding open-source platform for largescale streaming computation, which is widely used in the industry (eg., Twitter). Performance bottleneck problems encountered in streaming data applications motivate us to investigate scheduling issues in Storm. A key aspect of tuning Storm performance is to decide how to deploy components of a storm application among all available nodes in a cluster. Driven by our observations, we design and implement a new scheduling strategy called TOSS based on application structures. Compared to the existing round-robin scheduler, TOSS not only judiciously handles tight-bind components, but also balances workloads by introducing a self-tuning mechanism in the deployment stage. We conduct experiments by applying two popular and distinct topologies to evaluate the performance of TOSS. The experimental results suggest that TOSS significantly boost the performance of the round-robin scheduler. ln particular, TOSS substantially improves the system throughput of Storm while shortens latency of Storm applications
Preliminary application of DNA barcoding toward the detection of viable plant propagules at an initial, international point-of-entry in Georgia, USA
No full text© 2020, Springer Nature Switzerland AG. Over 90% of global commercial trade occurs between seaports, which are initial points-of-entry for nonnative, potentially invasive propagules. As such, there is a need to develop means to both rapidly intercept and identify propagules as they arrive. Here, we focus on plant propagules that are assumed to be non-native, in seed form. Because standard morphological techniques alone are laborious and require taxonomic expertise, we sought to address if identification through barcoding of the plastid DNA (rbcL + matK genes) of plant seeds could improve current processes in the early detection and rapid response to prevent entry/establishment of nonnative plant species. This research conducted a preliminary foray to evaluate the utility of widely accepted plant plastid DNA barcodes to identify plant propagules (seeds, hereafter) collected from the air-intake grilles of refrigerated shipping containers of a single agricultural commodity arriving at the Port of Savannah, Georgia, USA. We ask four questions: (1) Can DNA barcoding be used to detect seeds collected from shipping containers at the port? (2) What is the genetic composition of propagules entering the port? (3) How do morphological identifications compare to those based on genetic analysis? (4) Are nonnative invasive plant species present on shipping containers entering the Port of Savannah? This research collected 11,044 seeds from 628 refrigerated shipping containers between 2015 and 2017. Seeds were then morphologically sorted into Seed Types. Barcoding of the matK and rbcL gene regions of the plastid genomes directly isolated from seeds resulted in poor amplification. This is likely due to a host of potential confounding factors. Therefore, we germinated seeds and utilized leaf-tissues for sequencing of these two gene regions. From BLASTn analyses, results returned top hits for a variety of species, with up to 22 possible nonnative plant species and one definite Federal Noxious Weed. This work investigates the interception application of DNA barcoding to improve agro- and bio-security issues posed by nonnative and invasive species. Though this study required the germination of the seeds to obtain leaf-tissue suitable for our DNA barcoding method, we effectively demonstrated seed viability. Our seed identification process was lengthy and understandably not feasible for real-time application. Therefore, we seek to improve our methods for future applications by testing other approaches that may better complement morphological identification. Next reasonable steps include improved extraction protocols, metabarcoding to generate DNA barcode sequences directly from groups of seeds harvested from shipping containers and implementing other next-generation sequencing techniques
Creating an oer collection of automatically scored practice exercises for computer science
No full text© 2020 Copyright held by the owner/author(s). Publication rights licensed to ACM. Open Educational Resources (OER) is one way to help reduce the cost of higher education. We created a repository of 90 (and growing) practice problems for learning introductory programming using Python 3. In order to provide immediate feedback to learners as well as alleviate the scoring burden on instructors, these exercises include tests for a popular automatic web based scoring platform. We have been using and refining these materials for the past four semesters and collecting student user survey data. Overall, students have had a positive reaction to the practice format
The Effect of Online Core Courses Enrollment on Student Success: The Case of University System of Georgia
No full text© 2020, © 2020 Taylor & Francis Group, LLC. This study examines the impact of online core courses on students’ academic and financial outcomes of postsecondary students. To do so, we analyzed data from a large sample of students in the University System of Georgia (USG), governing agency of Georgia’s 26 public universities and colleges. Since 2001, USG has offered “eCore” courses: lower-division core curriculum courses that are offered fully online to students enrolled in either face-to-face or fully online programs, and satisfy requirements at any USG institution. Our dataset contains students seeking associate degrees (N = 103,684) and bachelor’s degrees (N = 238,648) analyzed independently. Our research investigates the impact that eCore has on student retention, graduation, and loan accumulation. Our findings show that students who took eCore courses enrolled in more semesters regardless of the degree being sought. Associate-seeking students who enrolled in eCore courses were more likely to graduate and took on fewer loans on average
Top to bottom: an expanded ranking of economics journals
No full text© 2020 Informa UK Limited, trading as Taylor & Francis Group. In what we believe is the largest ranking of its kind in economics, this study extends the economics journal ranking literature by examining the impact of papers published in more than 550 economics journals. Based on Google Scholar citations per article to all articles published in the 15-year period from 2001 through 2015, we find that the top five journals are the American Economic Review, Quarterly Journal of Economics, Journal of Financial Economics, Journal of Political Economy and Journal of Economic Perspectives. Moreover, three of the American Economic Association’s newest journals–American Economic Journal: Applied Economics, American Economic Journal: Macroeconomics, and American Economic Journal: Economic Policy–are ranked among the top 30 economics journals. An expanded ranking such as that provided in this study is likely a useful tool for researchers, particularly the new ones, in navigating the field of economics
Positionality and Participatory Ethics in the Global South: Critical Reflections on and Lessons Learned from Fieldwork Failure
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Liberia Migration Project
No full textThe Liberia Migration Project created by two classes (Advanced Community Geography fall 2019 and Introduction to Digital Humanities spring 2020). Was a reciprocal partnership between the documentary film company Azilia Films, who plans to produce a history of our long-lived connections between Liberia and the Lower Chattahoochee River, and the Columbus Community Geography Center at Columbus State University. In fall 2019, students used mix methods to engage local residents in an Oral History Harvest and GIS technologies to identify folks in our region who might be related to 100 families that left the Lower Chattahoochee Region for Liberia in 1867 and 1868. In spring 2020, students analyzed digitized data from The African Repository and Colonial Journal published by the American Colonialism Society to help place the 100 families that left our region in a broader context of all emigres who left the region during 1867 and 1868. We share that data (in spreadsheet form) along with the date of numbers of emigres from all sailings, and the maps of the locations that emigres left and their first place of settlement. This digital publication shares that information, along with a timeline of events and a discussion of the social, economic and political context in which folks from Columbus, Georgia found themselves in as they made the decision to leave the region and the United States for a new life in West Africa
Recombinant Expression of Preptin Analogs for Alanine Scanning Mutagenesis of Residues 27-29
Get PDFThe novel peptide preptin consists of 34 amino acid residues corresponding to Asp69-Leu102 of proinsulin-like growth factor E-peptide. Preptin has been isolated from pancreatic beta cells, and it has been found to exhibit both metabolic and mitogenic activities. This makes preptin an attractive candidate to treat insulin-independent diabetes and osteoporosis. Alanine scanning mutagenesis was utilized to substitute an alanine for residues Trp27, Arg28, and Gln29 of preptin in order to ultimately study the structure-activity relationship of these residues to preptin’s metabolic activity
Exploring Interactions of Phyllosphere Epiphytes with Plant Pathogenic Bacteria Pseudomonas and Xanthomonas on Tomato
Get PDFRecent studies have indicated the importance of resident microflora of plants in contributing towards overall plant health. Among difference components of the plant microbiome, Methylobacterium and Sphingomonas have been recognized as common residents of the phyllosphere for many host plants, however their role in disease control needs to be further investigated. The purpose of this study was to conduct experiments investigating the effectiveness of phyllosphere Methylobacterium and Sphingomonas isolated from red clover against common tomato phyllosphere bacterial pathogens, Pseudomonas syringae pv. tomato and Xanthomonas perforans. Additionally, this study uses X. perforans wild-type and X. perforans type VI secretion system (T6SS) mutant strains to observe the role of type VI secretion system in infection with a potential biocontrol agent. To explain interactions among the phyllosphere residents, nutritional similarity, motility and direct inhibition were observed in vitro. Based off the literature, it was hypothesized that Sphingomonas would prove to be a potential biocontrol agent against P. syringae pv. tomato, X. perforans wild-type and T6SS mutant. Methylobacteria would not prove to be a potential biocontrol agent against P. syrinage pv. tomato nor X. perforans wild-type and mutant. Lastly, it was hypothesized that X. perforans wild-type would be more virulent than the X. perforans T6SS when competing with a potential biocontrol agent (red clover commensal).
In planta experiments under growth chamber conditions indicated no significant change in disease with seeds that were soaked in a mix of red clover commensals when dipped in phyllosphere pathogens P. syringae pv. tomato and X. perforans wild-type and T6SS mutant. P. syringae pv. tomato was unable to infect control tomato plants in trial two under growth chamber conditions, and was not tested further in planta. In vitro testing indicated a red clover phyllosphere commensal, S. taxi 55669, inhibited X. perforans wild-type and mutant colonies on R2a plates. Therefore, S. taxi 55669 was studied for disease protection further in the greenhouse with seedling dip experiments. To assess the effectiveness of S. taxi 55669 in planta, foliar disease percent and bacterial population counts were recorded on bacterial dipped seedlings coinoculated with phyllopshere pathogens X. perforans wild-type and T6SS mutant. It is not recommended that S. taxi 55669 serve as a potential biocontrol for P. syringae pv. tomato 99B799 ba ed off the neutral effect S. taxi 55669 had with in vitro testing. Methylobacteria observed in this study, did not show any benefits against disease against P. syringae pv. tomato and X. perforans wild-type and T6SS mutant. However, the results from this study indicate S. taxi 55669 should be studied further for plant health, and has potential as a biocontrol against X. perforans. X. perforans T6SS mutant was found to be less virulent in the presence of S. taxi 55669, than X. perforans wild-type. Based off the high NOI and decrease in foliar disease, this study shows S. taxi 5669 has potential as a biocontrol for X. perforans. The decrease in motility and bacterial populations of X. perforans T6SS mutant when in the presence of S. taxi 55669 highlights the importance of icmF3 in motility and ability to attack resident phyllosphere bacteria. The lack of differentiation between direct inhibition on R2a plates of X. perforans wildtype and T6SS mutant in the presence of S. taxi 55669 indicates a part of the T6SS mutant system may still be functional