1,851 research outputs found

    Surface Defect Classification for Hot-Rolled Steel Strips by Selectively Dominant Local Binary Patterns

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    Developments in defect descriptors and computer vision-based algorithms for automatic optical inspection (AOI) allows for further development in image-based measurements. Defect classification is a vital part of an optical-imaging-based surface quality measuring instrument. The high-speed production rhythm of hot continuous rolling requires an ultra-rapid response to every component as well as algorithms in AOI instrument. In this paper, a simple, fast, yet robust texture descriptor, namely selectively dominant local binary patterns (SDLBPs), is proposed for defect classification. First, an intelligent searching algorithm with a quantitative thresholding mechanism is built to excavate the dominant non-uniform patterns (DNUPs). Second, two convertible schemes of pattern code mapping are developed for binary encoding of all uniform patterns and DNUPs. Third, feature extraction is carried out under SDLBP framework. Finally, an adaptive region weighting method is built for further strengthening the original nearest neighbor classifier in the feature matching stage. The extensive experiments carried out on an open texture database (Outex) and an actual surface defect database (Dragon) indicates that our proposed SDLBP yields promising performance on both classification accuracy and time efficiencyPeer reviewe

    Inbreeding ratio and genetic relationships among strains of the Western clawed frog, Xenopus tropicalis

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    The Western clawed frog, Xenopus tropicalis, is a highly promising model amphibian, especially in developmental and physiological research, and as a tool for understanding disease. It was originally found in the West African rainforest belt, and was introduced to the research community in the 1990s. The major strains thus far known include the Nigerian and Ivory Coast strains. However, due to its short history as an experimental animal, the genetic relationship among the various strains has not yet been clarified, and establishment of inbred strains has not yet been achieved. Since 2003 the Institute for Amphibian Biology (IAB), Hiroshima University has maintained stocks of multiple X. tropicalis strains and conducted consecutive breeding as part of the National BioResource Project. In the present study we investigated the inbreeding ratio and genetic relationship of four inbred strains at IAB, as well as stocks from other institutions, using highly polymorphic microsatellite markers and mitochondrial haplotypes. Our results show successive reduction of heterozygosity in the genome of the IAB inbred strains. The Ivory Coast strains clearly differed from the Nigerian strains genetically, and three subgroups were identified within both the Nigerian and Ivory Coast strains. It is noteworthy that the Ivory Coast strains have an evolutionary divergent genetic background. Our results serve as a guide for the most effective use of X. tropicalis strains, and the long-term maintenance of multiple strains will contribute to further research efforts

    Shape-induced force fields in optical trapping

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    Advances in optical tweezers, coupled with the proliferation of two-photon polymerization systems, mean that it is now becoming routine to fabricate and trap non-spherical particles. The shaping of both light beams and particles allows fine control over the flow of momentum from the optical to mechanical regimes. However, understanding and predicting the behaviour of such systems is highly complex in comparison with the traditional optically trapped microsphere. In this Article, we present a conceptually new and simple approach based on the nature of the optical force density. We illustrate the method through the design and fabrication of a shaped particle capable of acting as a passive force clamp, and we demonstrate its use as an optically trapped probe for imaging surface topography. Further applications of the design rules highlighted here may lead to new sensors for probing biomolecule mechanics, as well as to the development of optically actuated micromachines

    Considering the Case for Biodiversity Cycles: Reexamining the Evidence for Periodicity in the Fossil Record

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    Medvedev and Melott (2007) have suggested that periodicity in fossil biodiversity may be induced by cosmic rays which vary as the Solar System oscillates normal to the galactic disk. We re-examine the evidence for a 62 million year (Myr) periodicity in biodiversity throughout the Phanerozoic history of animal life reported by Rohde & Mueller (2005), as well as related questions of periodicity in origination and extinction. We find that the signal is robust against variations in methods of analysis, and is based on fluctuations in the Paleozoic and a substantial part of the Mesozoic. Examination of origination and extinction is somewhat ambiguous, with results depending upon procedure. Origination and extinction intensity as defined by RM may be affected by an artifact at 27 Myr in the duration of stratigraphic intervals. Nevertheless, when a procedure free of this artifact is implemented, the 27 Myr periodicity appears in origination, suggesting that the artifact may ultimately be based on a signal in the data. A 62 Myr feature appears in extinction, when this same procedure is used. We conclude that evidence for a periodicity at 62 Myr is robust, and evidence for periodicity at approximately 27 Myr is also present, albeit more ambiguous.Comment: Minor modifications to reflect final published versio

    Parasitic pneumonia in roe deer (Capreolus capreolus) in Cornwall, Great Britain, caused by Varestrongylus capreoli (Protostrongylidae)

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    Abstract Background Roe deer (Capreolus capreolus) became extinct over large areas of Britain during the post mediaeval period but following re-introductions from Europe during the 1800s and early 1900s the population started to recover and in recent decades there has been a spectacular increase. Many roe deer are shot in Britain each year but despite this there is little published information on the diseases and causes of mortality of roe deer in Great Britain. Case presentation The lungs of two hunter-shot roe deer in Cornwall showed multiple, raised, nodular lesions associated with numerous protostrongylid-type nematode eggs and first stage larvae. There was a pronounced inflammatory cell response (mostly macrophages, eosinophils and multinucleate giant cells) and smooth muscle hypertrophy of the smaller bronchioles. The morphology of the larvae was consistent with that of a Varestrongylus species and sequencing of an internal transcribed spacer-2 fragment confirmed 100% identity with a published Norwegian Varestrongylus cf. capreoli sequence. To the best of the authors’ knowledge this is the first confirmed record of V. capreoli in Great Britain. Co-infection with an adult protostrongylid, identified by DNA sequencing as Varestrongylus sagittatus, was also demonstrated in one case. Conclusions Parasitic pneumonia is regarded as a common cause of mortality in roe deer and is typically attributed to infection with Dictyocaulus sp. This study has shown that Varestrongylus capreoli also has the capability to cause significant lung pathology in roe deer and heavy infection could be of clinical significance

    Improved annotation of 3' untranslated regions and complex loci by combination of strand-specific direct RNA sequencing, RNA-seq and ESTs

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    The reference annotations made for a genome sequence provide the framework for all subsequent analyses of the genome. Correct annotation is particularly important when interpreting the results of RNA-seq experiments where short sequence reads are mapped against the genome and assigned to genes according to the annotation. Inconsistencies in annotations between the reference and the experimental system can lead to incorrect interpretation of the effect on RNA expression of an experimental treatment or mutation in the system under study. Until recently, the genome-wide annotation of 3-prime untranslated regions received less attention than coding regions and the delineation of intron/exon boundaries. In this paper, data produced for samples in Human, Chicken and A. thaliana by the novel single-molecule, strand-specific, Direct RNA Sequencing technology from Helicos Biosciences which locates 3-prime polyadenylation sites to within +/- 2 nt, were combined with archival EST and RNA-Seq data. Nine examples are illustrated where this combination of data allowed: (1) gene and 3-prime UTR re-annotation (including extension of one 3-prime UTR by 5.9 kb); (2) disentangling of gene expression in complex regions; (3) clearer interpretation of small RNA expression and (4) identification of novel genes. While the specific examples displayed here may become obsolete as genome sequences and their annotations are refined, the principles laid out in this paper will be of general use both to those annotating genomes and those seeking to interpret existing publically available annotations in the context of their own experimental dataComment: 44 pages, 9 figure

    RNA-Seq reveals large quantitative differences between the transcriptomes of outbreak and non-outbreak locusts

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    Outbreaks of locust populations repeatedly devastate economies and ecosystems in large parts of the world. The consequent behavioural shift from solitarious to gregarious and the concomitant changes in the locusts’ biology are of relevant scientific interest. Yet, research on the main locust species has not benefitted from recent advances in genomics. In this first RNA-Seq study on Schistocerca gregaria, we report two transcriptomes, including many novel genes, as well as differential gene expression results. In line with the large biological differences between solitarious and gregarious locusts, almost half of the transcripts are differentially expressed between their central nervous systems. Most of these transcripts are over-expressed in the gregarious locusts, suggesting positive correlations between the levels of activity at the population, individual, tissue and gene expression levels. We group these differentially expressed transcripts by gene function and highlight those that are most likely to be associated with locusts’ phase change either in a species-specific or general manner. Finally, we discuss our findings in the context of population-level and physiological events leading to gregariousness.M. Bakkali wishes to thank the Spanish Ministerio de Ciencia y Tecnología for the for the Ramón y Cajal fellowship and for the BFU2010-16438 grant that supported both this research and the FPI studentship to Rubén Martín Blázquez. We thank Mrs. Pernille Lavgesen for revision of the English language writing of this manuscript. We also thank the editor for the valuable comments on the manuscript
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