1,721,031 research outputs found
Mystus prabini, a new species of catfish (Siluriformes: Bagridae) from Arunachal Pradesh, north-eastern, India
No full textDarshan, Achom, Abujam, Santoshkumar, Kumar, Ram, Parhi, Janmejay, Singh, Yambem Suresh, Vishwanath, Waikhom, Das, Debangshu Narayan, Pandey, Pramod Kumar (2019): Mystus prabini, a new species of catfish (Siluriformes: Bagridae) from Arunachal Pradesh, north-eastern, India. Zootaxa 4648 (3): 511-522, DOI: 10.11646/zootaxa.4648.3.
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Nutrient and Bacterial Contamination Assessment and Filtration Media Selection for Dairy Cattle Drinking Water Treatment
Get PDFNitrate and bacterial groundwater pollution from dairy farms and surrounding croplands is a large and growing problem not only for surrounding ecosystems, but also for the health of the cattle consuming this untreated water if present at high enough levels. Point-of-use filtration methods could provide a low-cost means of removing such contaminants to within acceptable levels, but experimentation is needed to identify acceptable media and optimal treatment designs.This thesis is divided into four main chapters; the first chapter presents an introduction to the issue, pollutant health implications, and existing treatment options within a comprehensive literature review. The second chapter aims to assess the prevalence of nitrate and bacteria levels in dairy cattle water troughs throughout several dairy farms in central California. The purpose of the second chapter is to determine whether contaminant levels are within recommended levels as well as to identify the predominant source of each contamination to inform future design aspects of a treatment system. The third chapter aims to assess different commercially available, natural media for their ability to remove nitrate and bacteria through various column filtration and batch adsorption experiments. The fourth chapter outlines preliminary field-scale experiments conducted to assess removal potential at higher flow rates as well as identifies ways to further optimize for contaminant removal. While there are no set regulations for levels of either pollutant for dairy cattle water consumption, the general recommendation of 44 ppm NO3- was exceeded in 47% of the 62 troughs, and 89% of the 44 troughs analyzed for bacterial levels exceeded the recommended 15 CFU/100 mL total coliform count for adult cattle. These results suggest a significant portion of troughs would benefit from nitrate and bacteria reduction, and when alternative water sources are unavailable, column filtration may provide a sufficient treatment option. Of the filter media tested at lab scale, powdered activated carbon (PAC) provided the highest removal efficiency and adsorption capacity for both contaminants, but the high pressure required as well as its susceptibility to reduced long-term efficiency suggests that multi-media column filtration with PAC may improve the viability for a small-scale cattle drinking water filtration treatment system. Granular activated charcoal (GAC), which has larger particle size and lower surface area was found to achieve the second highest removal rate for both contaminants with lower pressure requirements, so column filtration with mixed media including both PAC and GAC is proposed and tested at field scale. While further optimization is required for the proposed treatment system, it offers a low cost and easily implementable treatment option for improving dairy cattle drinking water in troughs
A neighborhood statistics model for predicting stream pathogen indicator levels
Get PDFBecause elevated levels of water-borne Escherichia coli in streams are a leading cause of water quality impairments in the U.S., water-quality managers need tools for predicting aqueous E. coli levels. Presently, E. coli levels may be predicted using complex mechanistic models that have a high degree of unchecked uncertainty or simpler statistical models. To assess spatio-temporal patterns of instream E. coli levels, herein we measured E. coli, a pathogen indicator, at 16 sites (at four different times) within the Squaw Creek watershed, Iowa, and subsequently, the Markov Random Field model was exploited to develop a neighborhood statistics model for predicting instream E. coli levels. Two observed covariates, local water temperature (degrees Celsius) and mean cross-sectional depth (meters), were used as inputs to the model. Predictions of E. coli levels in the water column were compared with independent observational data collected from 16 in-stream locations. The results revealed that spatio-temporal averages of predicted and observed E. coli levels were extremely close. Approximately 66 % of individual predicted E. coli concentrations were within a factor of 2 of the observed values. In only one event, the difference between prediction and observation was beyond one order of magnitude. The mean of all predicted values at 16 locations was approximately 1 % higher than the mean of the observed values. The approach presented here will be useful while assessing instream contaminations such as pathogen/pathogen indicator levels at the watershed scale.This is a manuscript of an article published as Pandey, Pramod K., Gregory B. Pasternack, Mahbubul Majumder, Michelle L. Soupir, and Mark S. Kaiser. "A neighborhood statistics model for predicting stream pathogen indicator levels." Environmental Monitoring and Assessment 187, no. 3 (2015): 124. The final publication is available at Springer via https://doi.org/10.1007/s10661-014-4228-1. Posted with permission.</p
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
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Determination of prevalence of E. coli and Salmonella in dairy lagoon liquid manure and development of ozone and air injection treatment methods for pathogen reduction
Get PDFDairy industry is important for milk production and has substantial contribution to the California’s economy, however, dairy farms also produce manure, which impacts the environment. Dairy manure contains carbon, nitrogen and phosphorus, which are beneficial to soil. Manure also contains many bacteria including human pathogen, such as Salmonella and Escherichia coli (E. coli) which poses risk to public health. In this research, an intensive reconnaissance survey of manure stored in dairy lagoon was conducted to determine the prevalence of E. coli and Salmonella. In addition, an attempt was made to develop the ozone and air-based treatment method to reduce pathogen in liquid manure. First a comprehensive review on microbial pollution of manure, and various control method was performed (Chapter 1). Secondly, a field study was undertaken to collect dairy manure from 20 dairy farms to determine the prevalence of indicator E. coli, Shiga toxin producing E. coli (STEC), and E. coli O157:H7 (Chapter 2). Finally, a lab scale experiment was developed to determine the impact of ozone and air injection on E. coli inactivation in liquid manure (Chapter 3). The first chapter addresses the issues of microbial pathogen in manure and associated risk to human, animal and environment and impacts of various treatment methods on bacteria control. Previous studies showed that anaerobic digestion reduces E. coli and Salmonella under prolonged incubation and high temperature conditions, however, many anaerobic pathogens such as Clostridium survive anaerobic environment. In anaerobic incubation, E. coli level is reduced, but these bacteria are not eliminated completely. In the second chapter, several bacteria testing methods were used to determine the prevalence of E. coli, Salmonella, STEC and E. coli O157:H7 which are common pathogens in dairy manure. About 177 manure samples were collected from 20 dairy farms from primary and secondary lagoons to test the bacteria using agar culture-based methods, polymerase chain reaction (PCR) method for detection of E. coli and Salmonella. In addition, a real- time PCR based method was used to determine the presence of E coli O157:H7. Results showed that the prevalence of Salmonella in manure sample is lower than E. coli. The bacteria detection approach presented here could reduce the number of testing required during downstream confirmation process. The presence of Salmonella was found in 2.26 % of the samples, and both the culture-based and PCR methods yielded comparable outcomes in detecting Salmonella. Moreover, approximately 11.30% of the total samples out of the 177 were identified as positive for STEC by qPCR. None of the lagoon samples were positive to E coli O157:H7 by qPCR. The outcomes of this study hold substantial importance to determine the microbial quality of lagoon manure, and aid in the selection of appropriate methodologies for determining the prevalence of pathogenic organisms in dairy manure. In the third chapter, lab scale experiments were conducted to determine the impacts of ozone injection (Ozonation) and air injection (Aeration) in liquid dairy manure on E. coli reduction. Liquid manure was exposed to ozone and air for multiple durations (0 min, 60 min, 120 min, and 240 min) and E. coli levels were determined. Further, manure samples were analyzed for pH, salt content, potassium (K+), sodium (Na+), nitrate (NO3-), calcium (Ca2+), and electrical conductivity (EC, mS/cm). Results showed that Ozonation can be an effective treatment method to reduce E. coli levels in liquid manure. Further nitrate ions were reduced substantially by Ozonation. The analysis of variance (one way and two way) revealed significance difference in E. coli and nitrate reductions in liquid slurry among ozone and air treatments (p <0.05). The study's results carry significance importance in terms of developing a simple field-scale method for reducing microbial and nutrient pollutions from dairy lagoon manure
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
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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