416 research outputs found
Hamilton Decompositions of Graphs with Primitive Complements
No full textA graph G is a pair (V, E) where V is the set of vertices(or nodes) and E is the set of edges connecting the vertices. A graph is called k-regular, if all of its vertices are incident with k edges. A k-factor of a graph G is a k-regular spanning subgraph of G, and a Hamilton cycle is a connected 2-factor. So, a Hamilton cycle in G is a cycle that passes through all the vertices of G. A regular graph is called primitive, if it has no proper factors.
Also, a Hamilton decomposition of a graph G is a partition of the edges of G into edge-disjoint Hamilton cycles. Decompositions of graphs into Hamilton cycles with no Hamilton cycles in the complement, and into 2-factors with no 2-factors in the complement have been done in previous studies by D.G. Hoffman, C.A. Rodger, and A. Rosa. In this study, we find necessary and sufficient conditions for the existence of Hamilton decompositions of graphs with primitive complements. We also find sufficient conditions for the existence of Hamilton decompositions of graphs where the primitive complement is in a complete multipartite graph. We use a graph homomorphism technique, called amalgamation, for the proofs of the main results
Amalgamations and Detachments of Graphs and Hypergraphs
No full textA \textit{detachment} of a graph is a graph obtained from by splitting some or all of its vertices into more than one vertex. If is a function from into , then a \textit{-detachment} of is a detachment of in which each vertex of splits into vertices. is an \textit{amalgamation} of if there exists a function called an \textit{amalgamation function} from onto and a bijection such that joining and is in iff joining and is in .
We prove that for a given edge-colored graph there exists a detachment so that the result is a graph in which the edges are shared among the vertices in ways that are fair with respect to several notions of balance (such as between pairs of vertices, degrees of vertices in both the graph and in each color class, etc.). The connectivity of color classes is also addressed.
Most results in the literature on amalgamations focus on the detachments of amalgamated complete graphs and complete multipartite graphs. Many such results follow as immediate corollaries to the main result, which addresses amalgamations of graphs in general.
We exhibit some applications of this result in Hamiltonian decomposition of several families of graphs, and also we show that many known graph decomposition results can be obtained by a short proof using the main theorem. We study the companion embedding problems with many applications.
We then extend various results by Hilton, Nash-Williams and Rodger to hypergraphs. Such extensions provide a powerful tool to generalizes Baranyai's Theorems, and related results by Berge and Johnson.
We study several hypergraph embedding problems which will extend results of Brouwer, Schrijver, Baranyai, H{\"a}ggkvist and Hellgren.
In connection with Baranyai-Katona conjecture, we provide necessary and sufficient conditions for a complete uniform hypergraph to be connected factorizable, answering a question by Katona
The role of the tongue-of-ionization in the formation of the poleward wall of the main trough in the European post-midnight sector
No full textA series of radio tomography reconstructions from the University of Wales Aberystwyth receiver chains in Scandinavia and the UK, imaging the midnight-dawn sector on 13 December 2001, reveal a persistent large-scale electron density enhancement, which forms the poleward wall of the main ionization trough. Measurements by the European Incoherent Scatter radar (EISCAT) rule out in situ soft-particle precipitation as the main source of the higher densities. SuperDARN plasma drift observations and electric potential patterns place the feature in the dawn cell of the high-latitude convection, leading to the conclusion that the higher density is likely to have originated as photoionization and was convected over the polar cap to the nightside and around toward dawn in a tongue-of-ionization (TOI). Suitable runs of the Coupled ThermosphereIonosphere-Plasmasphere (CTIP) model support this interpretation and also reveal that the formation of the TOI is heavily UT dependent, which would lead to it being most prominent at nighttime in the European sector
Field studies in porcine epidemic diarrhea virus (PEDV) surveillance and control
No full textThe introduction of oral fluid-based sampling is a relatively new concept in diagnostic medicine which has been rapidly adopted by the swine industry. While the detection of porcine reproductive and respiratory syndrome virus (PRRSV) and influenza A (IAV) in oral fluids has been well documented, research on the detection of most other pathogens requires additional research.
Therefore, the objective of the study described in Chapter 3 was to describe PEDV detection patterns in growing pigs as shown by PEDV rRT-PCR testing of pen oral fluids. While feces have traditionally been the dominant sample for PEDV detection, the research in Chapter 3 describes oral fluids as a practical sample type for PEDV detection in growing pigs. Specifically, PEDV was detected in oral fluids until 69 days post exposure (DPE) which was longer than pen feces (55 DPE) and individual fecal swabs (41 DPE). PEDV Cq values in oral fluids were comparable to PEDV Cq values in pen feces; however, PEDV Cq values in oral fluids and pen feces were significantly higher than individual fecal swabs.
Chapter 3 described PEDV antibody kinetics, as shown by ELISA detection of IgA and IgG in individual pig serum and pen oral fluid samples and provided estimates of the cutoffs and performance of the PEDV "whole virus" IgA and IgG ELISAs. PEDV antibody responses (IgG and IgA) were detected in both serum and oral fluid by 10 - 14 days post exposure. The oral fluid PEDV IgA responses were particularly noteworthy with the maximum oral fluid IgA response reported at 96 DPE.
The investigators evaluated anamnestic antibody responses of gilts previously exposed to PEDV through vaccination using serum, colostrum, and milk samples in Chapter 4. Using 5 different vaccination protocols (unvaccinated controls and one and/or 2 doses of either Vaccine A or Vaccine B), the investigators found that two doses of vaccine did not booster immune responses any more than one dose of vaccine did. This was not unexpected since these gilts had been exposed to PEDV 8 months early. Nevertheless, the results in Chapter 4 demonstrate that vaccination can booster immune responses in previously exposed gilts.</p
Biosecurity Insights from the United States Swine Health Improvement Plan: Analyzing Data to Enhance Industry Practices
No full textBiosecurity practices aim to reduce the frequency of disease outbreaks in a farm, region, or country and play a pivotal role in fortifying the country’s pork industry against emerging threats, particularly foreign animal diseases (FADs). This article addresses the current biosecurity landscape of the US swine industry by summarizing the biosecurity practices reported by the producers through the United States Swine Health Improvement Plan (US SHIP) enrollment surveys, and it provides a general assessment of practices implemented. US SHIP is a voluntary, collaborative effort between industry, state, and federal entities regarding health certification programs for the swine industry. With 12,195 sites surveyed across 31 states, the study provides a comprehensive snapshot of current biosecurity practices. Key findings include variability by site types that have completed Secure Pork Supply plans, variability in outdoor access and presence of perimeter fencing, and diverse farm entry protocols for visitors. The data also reflect the industry’s response to the threat of FADs, exemplified by the implementation of the US SHIP in 2020. As the US SHIP program advances, these insights will guide industry stakeholders in refining biosecurity practices, fostering endemic re-emerging and FAD preparedness, and ensuring the sustainability of the swine industry in the face of evolving challenges.This article is published as Harlow, Michael, Montserrat Torremorell, Cristopher J. Rademacher, Jordan Gebhardt, Tyler Holck, Leticia CM Linhares, Rodger G. Main, and Giovani Trevisan. "Biosecurity Insights from the United States Swine Health Improvement Plan: Analyzing Data to Enhance Industry Practices." Animals 14, no. 7 (2024): 1134.
doi: https://doi.org/10.3390/ani14071134. Copyright: © 2024 by the authors. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/)
Rapid PRRSV-2 ORF5-based lineage classification using Nextclade
No full textPorcine reproductive and respiratory syndrome virus (PRRSV) continues to be a global challenge for swine health. Yim-Im et al. 2023 provides a standard genetic nomenclature, extending previously published works to better characterize PRRSV-2 ORF5-based genetic lineages on a global scale. To facilitate the use of this nomenclature, scaffold sequences, including historical and contemporary vaccines, were synthesized into a dataset designed for Nextclade v3.0. Metadata from the scaffold sequences representing year, country, and RFLP typing of the sequence were incorporated into the dataset. These scaffold sequences were processed through the Augur pipeline using DQ478308.1 as a reference strain for rooting and comparison. The resultant classifier can be accessed through the Nextclade website (https://clades.nextstrain.org/) or a link on the PRRSView homepage (https://prrsv.vdl.iastate.edu/). The resultant classifier functions the same as other classifiers hosted by the Nextclade core group and can provide phylogenetic-based PRRSV-2 ORF5 classifications on demand. Nextclade provides additional sequence metrics such as classification quality and notable mutations relative to the reference. The submitted sequences are grafted to the reference tree using phylogenetic placement, allowing for comparison to nearby sequences of reference viruses and vaccine strains. Additional comparisons between sequences can be made with metadata incorporated in the dataset. Although Nextclade is hosted as a webtool, the sequences are not uploaded to a server, and all analysis stay strictly confidential to the user. This work provides a standardized, trivial workflow facilitated by Nextclade to rapidly assign lineage classifications to PRRSV-2, identify mutations of interest, and compare contemporary strains to relevant vaccines.This article is published as Zeller, Michael A., Jennifer Chang, Giovani Trevisan, Rodger Main, Phillip C. Gauger, and Jianqiang Zhang. "Rapid PRRSV-2 ORF5-based lineage classification using Nextclade." Frontiers in Veterinary Science 11: 1419340. doi: https://doi.org/10.3389/fvets.2024.1419340
Detection of porcine epidemic diarrhea virus–neutralizing antibody using high-throughput imaging cytometry
No full textPorcine epidemic diarrhea virus (PEDV) is an emerging porcine coronavirus that causes a tremendous economic burden on the swine industry. The assessment of PEDV-neutralizing antibody levels provides a valuable tool to assess and predict herd immunity. We evaluated the performance of a PEDV imaging cytometry–based high-throughput neutralization test (HTNT) and compared the HTNT to a fluorescent focus neutralization (FFN) assay using serum samples from pigs of known PEDV infection status (n = 159). Estimates of diagnostic sensitivity and specificity for HTNT and FFN assays derived from receiver-operator characteristic (ROC) curve analyses showed that both PEDV FFN and HTNT provided excellent diagnostic performance. However, in the laboratory, imaging cytometry provided an objective and semi-automated approach that removed human subjectivity from the testing process and reduced the read-time of a 96-well plate to < 4 min. In addition, imaging cytometry facilitated the rapid collection and long-term storage of test images and data for further evaluation or client consultation. For PEDV and other pathogens, imaging cytometry could provide distinct advantages over classic virus neutralization or FFN assays for the detection and quantitation of neutralizing antibody.This is a manuscript of an article published as Sarmento, Luciana V., Korakrit Poonsuk, Liying Tian, Juan C. Mora-Díaz, Rodger G. Main, David H. Baum, Jeffrey J. Zimmerman, and Luis G. Giménez-Lirola. "Detection of porcine epidemic diarrhea virus–neutralizing antibody using high-throughput imaging cytometry." Journal of Veterinary Diagnostic Investigation 32, no. 2 (2020): 324-328. doi: https://doi.org/10.1177/1040638720903346. Posted with Permission. Copyright The Authors 2020
Newspaper journalism and the changing publics of multimedia cities
No full textThis document is a rendition of the poster that was presented at the ESF conference ‘Cities and Media: Cultural Perspectives on Urban Identities in a Mediatized World’, held 25-29 October 2006 in Vadstena, Sweden. It comprises a brief survey of one major theme of Scott Rodger' doctoral work: the future orientations of editors and managers – the attempts made to project the political (and economic) standing of the Toronto Star into the present and near future ‘multimedia city’
The Church of England and religious education during the twentieth century
No full textThis is the author accepted manuscript. The final version is available from JSTOR via the DOI in this record
Pathogenicity and immune response against porcine circovirus type 3 infection in caesarean-derived, colostrum-deprived pigs
No full textRecently, a novel PCV species (PCV3) has been detected in cases associated with sow mortality, lesions consistent with porcine dermatitis and nephropathy syndrome, reproductive failure and multisystemic inflammation. The pathogenesis and clinical significance of PCV3 is still unclear. In this study, we investigated the immunopathogenesis of PCV3 in CD/CD pigs. Four treatment groups, PCV3 (n=6), PCV3-KLH (n=6), control (n=3) and control-KLH (n=3), were included with PCV3-positive tissue homogenate (gc=3.38×1012 ml−1 and gc=1.04×1011 ml−1), confirmed by quantitative PCR (qPCR) and next-generation sequencing. Clinical signs, viremia, viral shedding, systemic cytokines, humoral (IgG) and T-cellular response were evaluated for 42 days. At necropsy, tissues were collected for histological evaluation and PCV3 detection by qPCR and in situ hybridization. No significant clinical signs were observed through the study. Viremia was detected in both PCV3-inoculated groups from 3 days post-inoculation (p.i.) until the end of the study. Nasal shedding was detected from 3 to 28 days p.i. and faecal shedding was transient. PCV3 induced an early (7 days p.i.) and sustained (42 days p.i.) IgG response. No significant T-cell response was observed. Histological evaluation demonstrated lesions consistent with multisystemic inflammation and perivasculitis. All tissues evaluated were positive by qPCR and virus replication was confirmed by positive in situ hybridization. This study demonstrated the potential role of PCV3 in subclinical infection, producing a mild, multisystemic inflammatory response, prolonged viremia detectable for 42 days p.i., presence of IgG humoral response and viral shedding in nasal secretions. More research is required to understand and elucidate potential co-factors necessary in the manifestation and severity of clinical disease.This article is published as Temeeyasen, Gun, Shay Lierman, Bailey L. Arruda, Rodger Main, Fabio Vannucci, Luis G. Gimenez-Lirola, and Pablo E. Piñeyro. "Pathogenicity and immune response against porcine circovirus type 3 infection in caesarean-derived, colostrum-deprived pigs." Journal of General Virology 102, no. 11 (2021): 001502.
DOI: 10.1099/jgv.0.001502
Copyright 2021 The Author(s)
Attribution 4.0 International (CC BY 4.0)
Posted with permission
- …
