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Sample records for extrachromosomal circles structurally

  1. Amplified DNAs in laboratory stocks of Leishmania tarentolae: extrachromosomal circles structurally and functionally similar to the inverted-H-region amplification of methotrexate-resistant Leishmania major

    SciTech Connect

    Petrillo-Peixoto, M.L.; Beverley, S.M. )

    1988-12-01

    We describe the structure of amplified DNA that was discovered in two laboratory stocks of the protozoan parasite Leishmania tarentolae. Restriction mapping and molecular cloning revealed that a region of 42 kilobases was amplified 8- to 30-fold in these lines. Southern blot analyses of digested DNAs or chromosomes separated by pulsed-field electrophoresis showed that the amplified DNA corresponded to the H region, a locus defined originally by its amplification in methotrexate-resistant Leishmania major. Similarities between the amplified DNA of the two species included (i) extensive cross-hybridization; (ii) approximate conservation of sequence order; (iii) extrachromosomal localization; (iv) an overall inverted, head-to-head configuration as a circular 140-kilobase tetrameric molecule; (v) two regions of DNA sequence rearrangement, each of which was closely associated with the two centers of the inverted repeats; (vi) association with methotrexate resistance; and (vii) phenotypically conservative amplification, in which the wild-type chromosomal arrangement was retained without apparent modification. Our data showed that amplified DNA mediating drug resistance arose in unselected L. tarentolae, although the pressures leading to apparently spontaneous amplification and maintenance of the H region are not known. The simple structure and limited extent of DNA amplified in these and other Leishmania lines suggests that the study of gene amplification in Leishmania spp. offers an attractive model system for the study of amplification in cultured mammalian cells and tumors. We also introduced a method for measuring the size of large circular DNAs, using gamma-irradiation to introduce limited double-strand breaks followed by sizing of the linear DNAs by pulsed-field electrophoresis.

  2. Identification of extrachromosomal circular DNA in hop via rolling circle amplification

    USDA-ARS?s Scientific Manuscript database

    During a survey looking for viruses affecting hop plants in the Willamette Valley of Oregon, a circular DNA molecule was identified via rolling circle amplification (RCA) and later characterized. The 5.7 kb long molecule only matched in a minor cover to a microsatellite region in the Humulus lupulus...

  3. Archaeal Extrachromosomal Genetic Elements

    PubMed Central

    Wang, Haina; Peng, Nan; Shah, Shiraz A.

    2015-01-01

    SUMMARY Research on archaeal extrachromosomal genetic elements (ECEs) has progressed rapidly in the past decade. To date, over 60 archaeal viruses and 60 plasmids have been isolated. These archaeal viruses exhibit an exceptional diversity in morphology, with a wide array of shapes, such as spindles, rods, filaments, spheres, head-tails, bottles, and droplets, and some of these new viruses have been classified into one order, 10 families, and 16 genera. Investigation of model archaeal viruses has yielded important insights into mechanisms underlining various steps in the viral life cycle, including infection, DNA replication and transcription, and virion egression. Many of these mechanisms are unprecedented for any known bacterial or eukaryal viruses. Studies of plasmids isolated from different archaeal hosts have also revealed a striking diversity in gene content and innovation in replication strategies. Highly divergent replication proteins are identified in both viral and plasmid genomes. Genomic studies of archaeal ECEs have revealed a modular sequence structure in which modules of DNA sequence are exchangeable within, as well as among, plasmid families and probably also between viruses and plasmids. In particular, it has been suggested that ECE-host interactions have shaped the coevolution of ECEs and their archaeal hosts. Furthermore, archaeal hosts have developed defense systems, including the innate restriction-modification (R-M) system and the adaptive CRISPR (clustered regularly interspaced short palindromic repeats) system, to restrict invasive plasmids and viruses. Together, these interactions permit a delicate balance between ECEs and their hosts, which is vitally important for maintaining an innovative gene reservoir carried by ECEs. In conclusion, while research on archaeal ECEs has just started to unravel the molecular biology of these genetic entities and their interactions with archaeal hosts, it is expected to accelerate in the next decade. PMID

  4. Energetics and structures of fullerene crop circles

    NASA Astrophysics Data System (ADS)

    Han, Jie

    1998-01-01

    The energetics and structures of carbon tori are studied using molecular simulation. They include circular and polygonal tori, formed by bending ( n, n) tubes and by joining ( n, n) and ( n+1, n-1) or ( n+2, n-2) tubes with pentagon-heptagon defects, respectively, in which n=5, 8 and 10. The strain energy of a circular and polygonal torus decreases by D-2 and D-1, respectively, where D is the torus diameter. Comparisons in average and local maximum strain suggest that defect-free circular tori are more energetically stable and kinetically accessible than defective polygonal tori. This confirms the hypothesis that circular tori are the predominant constituents of the observed fullerene crop circles in laser-grown single-wall carbon nanotubes.

  5. Extrachromosomal genetic elements in Micrococcus.

    PubMed

    Dib, Julián Rafael; Liebl, Wolfgang; Wagenknecht, Martin; Farías, María Eugenia; Meinhardt, Friedhelm

    2013-01-01

    Micrococci are Gram-positive G + C-rich, nonmotile, nonspore-forming actinomycetous bacteria. Micrococcus comprises ten members, with Micrococcus luteus being the type species. Representatives of the genus play important roles in the biodegradation of xenobiotics, bioremediation processes, production of biotechnologically important enzymes or bioactive compounds, as test strains in biological assays for lysozyme and antibiotics, and as infective agents in immunocompromised humans. The first description of plasmids dates back approximately 28 years, when several extrachromosomal elements ranging in size from 1.5 to 30.2 kb were found in Micrococcus luteus. Up to the present, a number of circular plasmids conferring antibiotic resistance, the ability to degrade aromatic compounds, and osmotolerance are known, as well as cryptic elements with unidentified functions. Here, we review the Micrococcus extrachromosomal traits reported thus far including phages and the only quite recently described large linear extrachromosomal genetic elements, termed linear plasmids, which range in size from 75 kb (pJD12) to 110 kb (pLMA1) and which confer putative advantageous capabilities, such as antibiotic or heavy metal resistances (inferred from sequence analyses and curing experiments). The role of the extrachromosomal elements for the frequently proven ecological and biotechnological versatility of the genus will be addressed as well as their potential for the development and use as genetic tools.

  6. Environmental Assessment: Disposition of Chiefs’ Circle Residential Structures

    DTIC Science & Technology

    2012-04-27

    soils potentially contaminated with Chlordane (a pesticide used in the past in MFH areas for the control of subterranean termites ). If Chlordane...subterranean termites . The pesticide was applied underground around the foundation of the housing units, so soils beneath and Chiefs’ Circle

  7. [Gambling addiction: the psychopathological structure of game-circle].

    PubMed

    Malygin, V L; Chugaevskaia, E V; Khvostikov, G S

    2010-01-01

    Thirty-two pathological gamblers were examined. The SCL-90-R, the LSI (Life Style Index) and the CSW questionnaires were used to evaluate psychopathological disorders. Based on the data obtained and the analysis of the development of pathological behavior, authors singled out 6 periods of the game-circle: 1) distress that directly followed the game (anxiety-depressive, obsessive-compulsive and paranoia disorders); 2) moderate anxiety-depressive disorders; 3) subdepressive disorders with predominance of asthenia and apathy; 4) anxiety and dysphoria comorbid with subdepression; 5) the narrow state of consciousness (game trans) preceding the relapse; 6) the return to game.

  8. Groups of line and circle diffeomorphisms. Criteria for almost nilpotency and structure theorems

    NASA Astrophysics Data System (ADS)

    Beklaryan, L. A.

    2016-08-01

    Almost nilpotency criteria and structure theorems are presented for the class of finitely generated groups of line and circle diffeomorphisms with mutually transversal elements. Key ingredients in the proof of the structure theorems are the existence/absence of an invariant measure, the (previously established) criterion for the existence of an invariant measure and restatements of this criterion in terms of various (topological, algebraic, combinatorial) characteristics of the group. The question of whether certain features of these characteristics or the existence of an invariant measure are typical for groups of line and circle diffeomorphisms is discussed. Bibliography: 34 titles.

  9. Automatic detection and quantification of WBCs and RBCs using iterative structured circle detection algorithm.

    PubMed

    Alomari, Yazan M; Sheikh Abdullah, Siti Norul Huda; Zaharatul Azma, Raja; Omar, Khairuddin

    2014-01-01

    Segmentation and counting of blood cells are considered as an important step that helps to extract features to diagnose some specific diseases like malaria or leukemia. The manual counting of white blood cells (WBCs) and red blood cells (RBCs) in microscopic images is an extremely tedious, time consuming, and inaccurate process. Automatic analysis will allow hematologist experts to perform faster and more accurately. The proposed method uses an iterative structured circle detection algorithm for the segmentation and counting of WBCs and RBCs. The separation of WBCs from RBCs was achieved by thresholding, and specific preprocessing steps were developed for each cell type. Counting was performed for each image using the proposed method based on modified circle detection, which automatically counted the cells. Several modifications were made to the basic (RCD) algorithm to solve the initialization problem, detecting irregular circles (cells), selecting the optimal circle from the candidate circles, determining the number of iterations in a fully dynamic way to enhance algorithm detection, and running time. The validation method used to determine segmentation accuracy was a quantitative analysis that included Precision, Recall, and F-measurement tests. The average accuracy of the proposed method was 95.3% for RBCs and 98.4% for WBCs.

  10. Automatic Detection and Quantification of WBCs and RBCs Using Iterative Structured Circle Detection Algorithm

    PubMed Central

    Alomari, Yazan M.; Zaharatul Azma, Raja

    2014-01-01

    Segmentation and counting of blood cells are considered as an important step that helps to extract features to diagnose some specific diseases like malaria or leukemia. The manual counting of white blood cells (WBCs) and red blood cells (RBCs) in microscopic images is an extremely tedious, time consuming, and inaccurate process. Automatic analysis will allow hematologist experts to perform faster and more accurately. The proposed method uses an iterative structured circle detection algorithm for the segmentation and counting of WBCs and RBCs. The separation of WBCs from RBCs was achieved by thresholding, and specific preprocessing steps were developed for each cell type. Counting was performed for each image using the proposed method based on modified circle detection, which automatically counted the cells. Several modifications were made to the basic (RCD) algorithm to solve the initialization problem, detecting irregular circles (cells), selecting the optimal circle from the candidate circles, determining the number of iterations in a fully dynamic way to enhance algorithm detection, and running time. The validation method used to determine segmentation accuracy was a quantitative analysis that included Precision, Recall, and F-measurement tests. The average accuracy of the proposed method was 95.3% for RBCs and 98.4% for WBCs. PMID:24803955

  11. Extrachromosomal elements in lower eukaryotes:

    SciTech Connect

    Wickner, R.B.; Hinnebusch, A.; Lambowitz, A.M.; Gunsalus, I.C.; Hollaender, A.

    1986-01-01

    While most genes are chromosomal, the nonchromosomal genes have played a disproportionate role in molecular biology, in part because of their easy accessibility and in part because they represent the most mobile portion of a cell's genome. Fungi, yeasts, protozoa, slime molds, algae, and other single-celled nucleated species, have recently gained dramatic popularity with the development of transformation methods for Saccharomyces, Neurospora, Schizosaccharomyces, Dictyostelium, and others of this group. The realization that Saccharomyces has oncogenes, RNA tumor viruses, intervening sequences, and all the mitotic, mitochondrial, and other structures typical of so-called ''higher'' eukaryotic organisms has confirmed the use of such organisms as model systems. Their use in biotechnology also shows great promise. The study in lower eukaryotes of mitochondria and chloroplasts has yielded many insights into similar structures in higher organisms as well as many unexpected finds, such as mechanisms of intron excision and the biology of introns, RNA catalysis, variation of the genetic code, and mechanisms of protein import across membranes.

  12. Genome-wide Purification of Extrachromosomal Circular DNA from Eukaryotic Cells.

    PubMed

    Møller, Henrik D; Bojsen, Rasmus K; Tachibana, Chris; Parsons, Lance; Botstein, David; Regenberg, Birgitte

    2016-04-04

    Extrachromosomal circular DNAs (eccDNAs) are common genetic elements in Saccharomyces cerevisiae and are reported in other eukaryotes as well. EccDNAs contribute to genetic variation among somatic cells in multicellular organisms and to evolution of unicellular eukaryotes. Sensitive methods for detecting eccDNA are needed to clarify how these elements affect genome stability and how environmental and biological factors induce their formation in eukaryotic cells. This video presents a sensitive eccDNA-purification method called Circle-Seq. The method encompasses column purification of circular DNA, removal of remaining linear chromosomal DNA, rolling-circle amplification of eccDNA, deep sequencing, and mapping. Extensive exonuclease treatment was required for sufficient linear chromosomal DNA degradation. The rolling-circle amplification step by φ29 polymerase enriched for circular DNA over linear DNA. Validation of the Circle-Seq method on three S. cerevisiae CEN.PK populations of 10(10) cells detected hundreds of eccDNA profiles in sizes larger than 1 kilobase. Repeated findings of ASP3-1, COS111, CUP1, RSC30, HXT6, HXT7 genes on circular DNA in both S288c and CEN.PK suggests that DNA circularization is conserved between strains at these loci. In sum, the Circle-Seq method has broad applicability for genome-scale screening for eccDNA in eukaryotes as well as for detecting specific eccDNA types.

  13. Gene editing activity on extrachromosomal arrays in C. elegans transgenics.

    PubMed

    Falgowski, Kerry A; Kmiec, Eric B

    2011-04-15

    Gene editing by modified single-stranded oligonucleotides is a strategy aimed at inducing single base changes into the genome, generating a permanent genetic change. The work presented here explores gene editing capabilities in the model organism Caenorhabditis elegans. Current approaches to gene mutagenesis in C. elegans have been plagued by non-specificity and thus the ability to induce precise, directed alterations within the genome of C. elegans would offer a platform upon which structure/function analyses can be carried out. As such, several in vivo assay systems were developed to evaluate gene editing capabilities in C. elegans. Fluorescence was chosen as the selectable endpoint as fluorescence can be easily detected through the transparent worm body even from minimal expression. Two tissue specific fluorescent expression vectors containing either a GFP or mCherry transgene were mutagenized to create a single nonsense mutation within the open reading frame of each respective fluorescent gene. These served as the target site to evaluate the frequency of gene editing on extrachromosomal array transgenic lines. Extrachromosomal arrays can carry hundreds of copies of the transgene, therefore low frequency events (like those in the gene editing reaction) may be detected. Delivery of the oligonucleotide was accomplished by microinjection into the gonads of young adult worms in an effort to induce repair of the mutated fluorescent gene in the F1 progeny. Despite many microinjections on the transgenic strains with varying concentrations of ODNs, no gene editing events were detected. This result is consistent with the previous research, demonstrating the difficulties encountered in targeting embryonic stem cells and the pronuclei of single-celled embryos. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. The structure of kinetoplast DNA. 1. The mini-circles of Crithidia lucilae are heterogeneous in base sequence.

    PubMed

    Kleisen, M C; Borst, P; Weijers, P J

    1976-04-15

    We have analysed limit digests of mini-circles from kinetoplast DNA of Crithidia luciliae by gel electrophoresis. Endonucleases HapII and AluI cut the circles into at least 37 and 21 fragments, respectively, and leave no circles intact. In both cases the added molecular weights of the fragments, estimated from mobility in gels, exceeds 18 X 10(6), i.e. more than 12 times the molecular weight of the mini-circle DNA. Endonucleases HindII + III, EcoRI and HpaI cut only part of the circles. These results show that the mini-circles are heterogeneous in base sequence. Different sequence classes are present in different amounts. DNA-DNA renaturation analysis of mini-circle DNA yields a complexity of about 3 X 10(6), i.e. twice the molecular weight on one mini-circle. The delta tm of native and renatured duplexes is about 1 degree C, showing that the sequence heterogeneity is a micro-heterogeneity. Electron microscopy, gel electrophoresis and sedimentation analysis show that the circles that are not cut by endonucleases HindII + III remain catenated in very large associations. These associations lack the 'rosette' structures and the long edge loops characteristic of intact kinetoplast DNA. This suggests that the mini-circle classes cut by endonucleases HindII + III are present throughout the network and that the maxi-circle component of the network (see accompanying paper) is not essential to hold the network together. Prolonged electrophoresis on 1.5% or 2% agarose gels resolves the open mini-circles into three and linearized mini-circles into four bands, present in different amounts. We conclude that the mini-circles are also heterogeneous in size, the difference in size between the two extreme size classes being 4% of the contour length. Digestion with endonuclease HapII shows that at least three out of these four bands differ in sequence. Possible mechanisms that could account for the micro-heterogeneity in sequence of mini-circles are discussed.

  15. Clustered regularly interspaced short palindrome repeats (CRISPRs) have spacers of extrachromosomal origin.

    PubMed

    Bolotin, Alexander; Quinquis, Benoit; Sorokin, Alexei; Ehrlich, S Dusko

    2005-08-01

    Numerous prokaryote genomes contain structures known as clustered regularly interspaced short palindromic repeats (CRISPRs), composed of 25-50 bp repeats separated by unique sequence spacers of similar length. CRISPR structures are found in the vicinity of four genes named cas1 to cas4. In silico analysis revealed another cluster of three genes associated with CRISPR structures in many bacterial species, named here as cas1B, cas5 and cas6, and also revealed a certain number of spacers that have homology with extant genes, most frequently derived from phages, but also derived from other extrachromosomal elements. Sequence analysis of CRISPR structures from 24 strains of Streptococcus thermophilus and Streptococcus vestibularis confirmed the homology of spacers with extrachromosomal elements. Phage sensitivity of S. thermophilus strains appears to be correlated with the number of spacers in the CRISPR locus the strain carries. The authors suggest that the spacer elements are the traces of past invasions by extrachromosomal elements, and hypothesize that they provide the cell immunity against phage infection, and more generally foreign DNA expression, by coding an anti-sense RNA. The presence of gene fragments in CRISPR structures and the nuclease motifs in cas genes of both cluster types suggests that CRISPR formation involves a DNA degradation step.

  16. Clustered regularly interspaced short palindrome repeats (CRISPRs) have spacers of extrachromosomal origin.

    PubMed

    Bolotin, Alexander; Quinquis, Benoit; Sorokin, Alexei; Ehrlich, S Dusko

    2005-08-01

    Numerous prokaryote genomes contain structures known as clustered regularly interspaced short palindromic repeats (CRISPRs), composed of 25-50 bp repeats separated by unique sequence spacers of similar length. CRISPR structures are found in the vicinity of four genes named cas1 to cas4. In silico analysis revealed another cluster of three genes associated with CRISPR structures in many bacterial species, named here as cas1B, cas5 and cas6, and also revealed a certain number of spacers that have homology with extant genes, most frequently derived from phages, but also derived from other extrachromosomal elements. Sequence analysis of CRISPR structures from 24 strains of Streptococcus thermophilus and Streptococcus vestibularis confirmed the homology of spacers with extrachromosomal elements. Phage sensitivity of S. thermophilus strains appears to be correlated with the number of spacers in the CRISPR locus the strain carries. The authors suggest that the spacer elements are the traces of past invasions by extrachromosomal elements, and hypothesize that they provide the cell immunity against phage infection, and more generally foreign DNA expression, by coding an anti-sense RNA. The presence of gene fragments in CRISPR structures and the nuclease motifs in cas genes of both cluster types suggests that CRISPR formation involves a DNA degradation step.

  17. Excision and replication of extrachromosomal DNA of pea (Pisum sativum)

    SciTech Connect

    Hof, J.V.; Bjerknes, C.A.; Delihas, N.C.

    1983-02-01

    Experiments with cultured pea roots were conducted to determine (i) whether extrachromosomal DNA was produced by cells in the late S phase or in the G2 phase of the cell cycle, (ii) whether the maturation of nascent DNA replicated by these cells achieved chromosomal size, (iii) when extrachromosomal DNA was removed from the chromosomal duplex, and (iv) the replication of nascent chains by the extrachromosomal DNA after its release from the chromosomal duplex. Autoradiography and cytophotometry of cells of carbohydrate-starved root tips revealed that extrachromosomal DNA was produced by a small fraction of cells accumulated in the late S phase after they had replicated about 80% of their DNA. Velocity sedimentation of nascent chromosomal DNA in alkaline sucrose gradients indicated that the DNA of cells in the late S phase failed to achieve chromosomal size. After reaching sizes of 70 x 10/sup 6/ to 140 x 10/sup 6/ daltons, some of the nascent chromosomal molecules were broken, presumably releasing extrachromosomal DNA several hours later. Sedimentation of selectively extracted extrachromosomal DNA either from dividing cells or from those in the late S phase showed that it replicated two nascent chains, one of 3 x 10/sup 6/ daltons and another of 7 x 10/sup 6/ daltons. Larger molecules of extrachromosomal DNA were detectable after cells were labeled for 24 h. These two observations were compatible with the idea that the extrachromosomal DNA was first replicated as an integral part of the chromosomal duplex, was cut from the duplex, and then, once free of the chromosome, replicated two smaller chains of 3 x 10/sup 6/ and 7 x 10/sup 6/ daltons. 24 references.

  18. Nematode phospholipid metabolism: an example of closing the genome-structure-function circle

    PubMed Central

    Lee, Soon Goo; Jez, Joseph M.

    2014-01-01

    Parasitic nematodes that infect humans, animals, and plants cause health problems, livestock and agricultural losses, and economic damage worldwide and are important targets for drug development. The growing availability of nematode genomes supports the discovery of new pathways that differ from host organisms and are a starting point for structural and functional studies of novel antiparasitic targets. As an example of how genome data, structural biology, and biochemistry integrate into a research cycle targeting parasites, we summarize the discovery of the phosphobase methylation pathway for phospholipid synthesis in nematodes and compare the phosphoethanolamine methyltransferases from nematodes, plants, and Plasmodium. Crystallographic and biochemical studies of the phosphoethanolamine methyltransferases in this pathway provide a foundation that guides the next steps that close the genome-structure-function circle. PMID:24685202

  19. Extrachromosomal oncogene amplification drives tumour evolution and genetic heterogeneity.

    PubMed

    Turner, Kristen M; Deshpande, Viraj; Beyter, Doruk; Koga, Tomoyuki; Rusert, Jessica; Lee, Catherine; Li, Bin; Arden, Karen; Ren, Bing; Nathanson, David A; Kornblum, Harley I; Taylor, Michael D; Kaushal, Sharmeela; Cavenee, Webster K; Wechsler-Reya, Robert; Furnari, Frank B; Vandenberg, Scott R; Rao, P Nagesh; Wahl, Geoffrey M; Bafna, Vineet; Mischel, Paul S

    2017-03-02

    Human cells have twenty-three pairs of chromosomes. In cancer, however, genes can be amplified in chromosomes or in circular extrachromosomal DNA (ecDNA), although the frequency and functional importance of ecDNA are not understood. We performed whole-genome sequencing, structural modelling and cytogenetic analyses of 17 different cancer types, including analysis of the structure and function of chromosomes during metaphase of 2,572 dividing cells, and developed a software package called ECdetect to conduct unbiased, integrated ecDNA detection and analysis. Here we show that ecDNA was found in nearly half of human cancers; its frequency varied by tumour type, but it was almost never found in normal cells. Driver oncogenes were amplified most commonly in ecDNA, thereby increasing transcript level. Mathematical modelling predicted that ecDNA amplification would increase oncogene copy number and intratumoural heterogeneity more effectively than chromosomal amplification. We validated these predictions by quantitative analyses of cancer samples. The results presented here suggest that ecDNA contributes to accelerated evolution in cancer.

  20. Quality Circles

    DTIC Science & Technology

    1990-04-09

    wi11. examine the origin, the elements +or a sucCessful program and problems in managing Luality Circles. END NOTES 1. Olga L. Crocker. Johnny...detailed plans are prepared for formal presentation to management. 15 END NOTES t J. M. Juran. "The 4C Circle Fhenomenon" In Quality Circles Selected...Management must advertise its commitment not to lay off employees as a result of quality circle sugqestions. 22 END NOTES 1. La-wrence J. Korb. "Progress

  1. Evaluating Restorative Justice Circles of Support and Accountability: Can Social Support Overcome Structural Barriers?

    PubMed

    Bohmert, Miriam Northcutt; Duwe, Grant; Hipple, Natalie Kroovand

    2016-06-05

    In a climate in which stigmatic shaming is increasing for sex offenders as they leave prison, restorative justice practices have emerged as a promising approach to sex offender reentry success and have been shown to reduce recidivism. Criminologists and restorative justice advocates believe that providing ex-offenders with social support that they may not otherwise have is crucial to reducing recidivism. This case study describes the expressive and instrumental social support required and received, and its relationship to key outcomes, by sex offenders who participated in Circles of Support and Accountability (COSAs), a restorative justice, reentry program in Minnesota. In-depth interviews with re-entering sex offenders and program volunteers revealed that 75% of offenders reported weak to moderate levels of social support leaving prison, 70% reported receiving instrumental support in COSAs, and 100% reported receiving expressive support. Findings inform work on social support, structural barriers, and restorative justice programming during sex offender reentry. © The Author(s) 2016.

  2. Linear extrachromosomal DNA in the morel Morchella conica.

    PubMed

    Meinhardt, F; Esser, K

    1984-01-01

    Altogether 18 different strains of the genus Morchella were assayed for the presence of extrachromosomal genetic elements. It was shown that 8 out of 13 strains of the Morchella conica group contain plasmids of comparable size (6 kb and 8 kb respectively). The 5 representatives of Morchella esculenta were not found to contain extrachromosomal DNA. The plasmid of one strain (nr. 3) was further analysed. By restriction analyses and electron microscopy it was confirmed that the plasmid is linear having a molecular weight of 6 kb. It was further shown that it carries at both ends inverted repeats of 0.75 kb.

  3. Exploring Writing Circles as Innovative, Collaborative Writing Structures with Teacher Candidates

    ERIC Educational Resources Information Center

    Roberts, Sherron Killingsworth; Blanch, Norine; Gurjar, Nandita

    2017-01-01

    Writing circles are "small groups... meeting regularly to share drafts, choose common writing topics, practice positive response, and in general, help each other become better writers" (Vopat, 2009, p. 6). In this exploratory study, writing circles were employed with elementary teacher candidates in hopes of enhancing their perceptions…

  4. Solving Problems through Circles

    ERIC Educational Resources Information Center

    Grahamslaw, Laura; Henson, Lisa H.

    2015-01-01

    Several problem-solving interventions that utilise a "circle" approach have been applied within the field of educational psychology, for example, Circle Time, Circle of Friends, Sharing Circles, Circle of Adults and Solution Circles. This research explored two interventions, Solution Circles and Circle of Adults, and used thematic…

  5. Solving Problems through Circles

    ERIC Educational Resources Information Center

    Grahamslaw, Laura; Henson, Lisa H.

    2015-01-01

    Several problem-solving interventions that utilise a "circle" approach have been applied within the field of educational psychology, for example, Circle Time, Circle of Friends, Sharing Circles, Circle of Adults and Solution Circles. This research explored two interventions, Solution Circles and Circle of Adults, and used thematic…

  6. Literature Circles.

    ERIC Educational Resources Information Center

    Katz, Claudia Anne; Kuby, Sue Ann

    2002-01-01

    Describes the use of literature circles, a student-led reading and discussion method that encourages students to see stories in various ways. Explains the student selection of titles, roles of group members, and collaborative projects that complete the activity. (LRW)

  7. Literature Circles.

    ERIC Educational Resources Information Center

    Pitman, Marge

    A study investigated whether using literature circles in the study of non-fiction improved student attitudes about reading and improved comprehension while developing self-confidence and cooperation. A purposeful sample of five students from a combined grade 5/6 class were chosen based on their negative responses about attitude and ability…

  8. Literature Circles.

    ERIC Educational Resources Information Center

    Katz, Claudia Anne; Kuby, Sue Ann

    2002-01-01

    Describes the use of literature circles, a student-led reading and discussion method that encourages students to see stories in various ways. Explains the student selection of titles, roles of group members, and collaborative projects that complete the activity. (LRW)

  9. Amplification of a Zygosaccharomyces bailii DNA segment in wine yeast genomes by extrachromosomal circular DNA formation.

    PubMed

    Galeote, Virginie; Bigey, Frédéric; Beyne, Emmanuelle; Novo, Maite; Legras, Jean-Luc; Casaregola, Serge; Dequin, Sylvie

    2011-03-10

    We recently described the presence of large chromosomal segments resulting from independent horizontal gene transfer (HGT) events in the genome of Saccharomyces cerevisiae strains, mostly of wine origin. We report here evidence for the amplification of one of these segments, a 17 kb DNA segment from Zygosaccharomyces bailii, in the genome of S. cerevisiae strains. The copy number, organization and location of this region differ considerably between strains, indicating that the insertions are independent and that they are post-HGT events. We identified eight different forms in 28 S. cerevisiae strains, mostly of wine origin, with up to four different copies in a single strain. The organization of these forms and the identification of an autonomously replicating sequence functional in S. cerevisiae, strongly suggest that an extrachromosomal circular DNA (eccDNA) molecule serves as an intermediate in the amplification of the Z. bailii region in yeast genomes. We found little or no sequence similarity at the breakpoint regions, suggesting that the insertions may be mediated by nonhomologous recombination. The diversity between these regions in S. cerevisiae represents roughly one third the divergence among the genomes of wine strains, which confirms the recent origin of this event, posterior to the start of wine strain expansion. This is the first report of a circle-based mechanism for the expansion of a DNA segment, mediated by nonhomologous recombination, in natural yeast populations.

  10. Production of extrachromosomal microDNAs is linked to mismatch repair pathways and transcriptional activity

    PubMed Central

    Dillon, Laura W.; Kumar, Pankaj; Shibata, Yoshiyuki; Wang, Yuh-Hwa; Willcox, Smaranda; Griffith, Jack D.; Pommier, Yves; Takeda, Shunichi; Dutta, Anindya

    2015-01-01

    SUMMARY MicroDNAs are <400-base extrachromosomal circles found in mammalian cells. Tens of thousands of microDNAs have been found in all tissue types, including sperm. MicroDNAs arise preferentially from areas with high gene density, GC content, and exon density, from promoters with activating chromatin modifications and in sperm from the 5'-UTR of full-length LINE-1 elements, but are depleted from lamin-associated heterochromatin. Analysis of microDNAs from a set of human cancer cell lines revealed lineage-specific patterns of microDNA origins. A survey of microDNAs from chicken cells defective in various DNA repair proteins reveal that homologous recombination and nonhomologous end joining repair pathways are not required for microDNA production. Deletion of the MSH3 DNA mismatch repair protein results in a significant decrease in microDNA abundance, specifically from non-CpG genomic regions. Thus, microDNAs arise as part of normal cellular physiology; either from DNA breaks associated with RNA metabolism or from replication slippage followed by mismatch repair. PMID:26051933

  11. Amplification of a Zygosaccharomyces bailii DNA Segment in Wine Yeast Genomes by Extrachromosomal Circular DNA Formation

    PubMed Central

    Galeote, Virginie; Bigey, Frédéric; Beyne, Emmanuelle; Novo, Maite; Legras, Jean-Luc; Casaregola, Serge; Dequin, Sylvie

    2011-01-01

    We recently described the presence of large chromosomal segments resulting from independent horizontal gene transfer (HGT) events in the genome of Saccharomyces cerevisiae strains, mostly of wine origin. We report here evidence for the amplification of one of these segments, a 17 kb DNA segment from Zygosaccharomyces bailii, in the genome of S. cerevisiae strains. The copy number, organization and location of this region differ considerably between strains, indicating that the insertions are independent and that they are post-HGT events. We identified eight different forms in 28 S. cerevisiae strains, mostly of wine origin, with up to four different copies in a single strain. The organization of these forms and the identification of an autonomously replicating sequence functional in S. cerevisiae, strongly suggest that an extrachromosomal circular DNA (eccDNA) molecule serves as an intermediate in the amplification of the Z. bailii region in yeast genomes. We found little or no sequence similarity at the breakpoint regions, suggesting that the insertions may be mediated by nonhomologous recombination. The diversity between these regions in S. cerevisiae represents roughly one third the divergence among the genomes of wine strains, which confirms the recent origin of this event, posterior to the start of wine strain expansion. This is the first report of a circle-based mechanism for the expansion of a DNA segment, mediated by nonhomologous recombination, in natural yeast populations. PMID:21423766

  12. Production of Extrachromosomal MicroDNAs Is Linked to Mismatch Repair Pathways and Transcriptional Activity.

    PubMed

    Dillon, Laura W; Kumar, Pankaj; Shibata, Yoshiyuki; Wang, Yuh-Hwa; Willcox, Smaranda; Griffith, Jack D; Pommier, Yves; Takeda, Shunichi; Dutta, Anindya

    2015-06-23

    MicroDNAs are <400-base extrachromosomal circles found in mammalian cells. Tens of thousands of microDNAs have been found in all tissue types, including sperm. MicroDNAs arise preferentially from areas with high gene density, GC content, and exon density from promoters with activating chromatin modifications and in sperm from the 5'-UTR of full-length LINE-1 elements, but are depleted from lamin-associated heterochromatin. Analysis of microDNAs from a set of human cancer cell lines revealed lineage-specific patterns of microDNA origins. A survey of microDNAs from chicken cells defective in various DNA repair proteins reveals that homologous recombination and non-homologous end joining repair pathways are not required for microDNA production. Deletion of the MSH3 DNA mismatch repair protein results in a significant decrease in microDNA abundance, specifically from non-CpG genomic regions. Thus, microDNAs arise as part of normal cellular physiology—either from DNA breaks associated with RNA metabolism or from replication slippage followed by mismatch repair.

  13. Genomics of clostridial pathogens: implication of extrachromosomal elements in pathogenicity.

    PubMed

    Brüggemann, Holger

    2005-10-01

    The recently decoded genomes of the major clostridial toxin-producing pathogens Clostridium perfringens, Clostridium tetani, Clostridium botulinum and Clostridium difficile have provided a huge amount of new sequence data. Recent studies have focused on the identification and investigation of pathogenic determinants and the regulatory events governing their expression. The sequence data revealed also the genomic background of virulence genes, as well as the contribution of extrachromosomal elements to a pathogenic phenotype. This has generated new insights in clostridial pathogenesis - and will continue to do so in the future - and has deepened our understanding of the anaerobic lifestyle of clostridial species.

  14. Selective Entrapment of Extrachromosomally Amplified DNA by Nuclear Budding and Micronucleation during S Phase

    PubMed Central

    Shimizu, Noriaki; Itoh, Nobuo; Utiyama, Hiroyasu; Wahl, Geoffrey M.

    1998-01-01

    Acentric, autonomously replicating extrachromosomal structures called double-minute chromosomes (DMs) frequently mediate oncogene amplification in human tumors. We show that DMs can be removed from the nucleus by a novel micronucleation mechanism that is initiated by budding of the nuclear membrane during S phase. DMs containing c-myc oncogenes in a colon cancer cell line localized to and replicated at the nuclear periphery. Replication inhibitors increased micronucleation; cell synchronization and bromodeoxyuridine–pulse labeling demonstrated de novo formation of buds and micronuclei during S phase. The frequencies of S-phase nuclear budding and micronucleation were increased dramatically in normal human cells by inactivating p53, suggesting that an S-phase function of p53 minimizes the probability of producing the broken chromosome fragments that induce budding and micronucleation. These data have implications for understanding the behavior of acentric DNA in interphase nuclei and for developing chemotherapeutic strategies based on this new mechanism for DM elimination. PMID:9508765

  15. Circling Saturn

    NASA Image and Video Library

    2014-11-24

    Saturn is circled by its rings (seen nearly edge-on in this image), as well as by the moons Tethys (the large bright body near the lower right hand corner of this image) and Mimas (seen as a slight crescent against Saturn's disk above the rings, at about 4 o'clock). The shadows of the rings, each ringlet delicately recorded across Saturn's face, also circle around Saturn's south pole. Although the rings and larger moons of Saturn mostly orbit very near the planet's equatorial plane, this image shows that they do not all lie precisely in the orbital plane. Part of the reason that Mimas (246 miles, or 396 kilometers across) and Tethys (660 miles, or 1062 kilometers across) appear above and below the ring plane because their orbits are slightly inclined (about 1 to 1.5 degrees) relative to the rings. This view looks toward the sunlit side of the rings from slightly above the ringplane. The image was taken in visible light with the Cassini spacecraft wide-angle camera on Aug. 14, 2014. The view was obtained at a distance of approximately 1.1 million miles (1.7 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 23 degrees. Image scale is 63 miles (102 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA18288

  16. Sequencing the extrachromosomal circular mobilome reveals retrotransposon activity in plants

    PubMed Central

    Llauro, Christel; Jobet, Edouard; Robakowska-Hyzorek, Dagmara; Lasserre, Eric; Ghesquière, Alain; Panaud, Olivier

    2017-01-01

    Retrotransposons are mobile genetic elements abundant in plant and animal genomes. While efficiently silenced by the epigenetic machinery, they can be reactivated upon stress or during development. Their level of transcription not reflecting their transposition ability, it is thus difficult to evaluate their contribution to the active mobilome. Here we applied a simple methodology based on the high throughput sequencing of extrachromosomal circular DNA (eccDNA) forms of active retrotransposons to characterize the repertoire of mobile retrotransposons in plants. This method successfully identified known active retrotransposons in both Arabidopsis and rice material where the epigenome is destabilized. When applying mobilome-seq to developmental stages in wild type rice, we identified PopRice as a highly active retrotransposon producing eccDNA forms in the wild type endosperm. The mobilome-seq strategy opens new routes for the characterization of a yet unexplored fraction of plant genomes. PMID:28212378

  17. Identification, characterization and preliminary X-ray diffraction analysis of the rolling-circle replication initiator protein from plasmid pSTK1.

    PubMed

    Carr, Stephen B; Mecia, Lauren B; Phillips, Simon E V; Thomas, Christopher D

    2013-10-01

    Antibiotic resistance in bacterial pathogens poses an ever-increasing risk to human health. In antibiotic-resistant strains of Staphylococcus aureus this resistance often resides in extra-chromosomal plasmids, such as those of the pT181 family, which replicate via a rolling-circle mechanism mediated by a plasmid-encoded replication initiation protein. Currently, there is no structural information available for the pT181-family Rep proteins. Here, the crystallization of a catalytically active fragment of a homologous replication initiation protein from the thermophile Geobacillus stearothermophilus responsible for the replication of plasmid pSTK1 is reported. Crystals of the RepSTK1 fragment diffracted to a resolution of 2.5 Å and belonged to space group P2₁2₁2₁.

  18. Characterization of extrachromosomal DNA in the flesh fly Sarcophaga bullata.

    PubMed

    Samols, D; Swift, H

    1979-11-01

    The polytene pupal foot pad cells of the flesh fly Sarcophaga bullata contain numerous extrachromosomal DNA containing granules. We have determined both the origin and the nature of the DNA sequences present in these granules. Studies done with quinacrine staining of seven day old pupal foot-pad polytene nuclei showed that the granules fluoresced very brightly while the chromosomal bands to which the granules were attached did not. The only other highly fluorescent regions of the polytene karyotype were the centromeric heterochromatin of chromosomes C and E and several bands associated with the nucleolus of Chromsome A. When polytene nuclei were hybridized in situ with cRNA made from highly repetitive DNA, many of the granules positively labeled. Most of the label on these slides was concentrated on the centromeric heterochromatin of chromosomes C and E. Quinacrine staining of the foot-pad cells at very early stages of pupal development showed that when granules were present, they were always closely associated with the same two centromeric regions, those of chromosomes C and E. Since the highly repetitive DNA located in these centromeric regions is underreplicated, we conclude that the granules result from an extrusion process which takes place early during the polytenization of these cells. The chromosomal integrity of the centromeric heterochromatin of chromosomes C and E is apparently disrupted and repetitive sequences are dissociated from the chromosomes as DNA granules which then secondarily become associated with chromosomal bands throughout the nucleus.

  19. Isolation and characterization of extrachromosomal circular DNAs in mouse heart, brain and liver tissues at various ages

    SciTech Connect

    Flores, S.C.

    1988-01-01

    Eucaryotic cells contains extrachromosomal circular (eccDNAs) which can be separated and distinguished from chromosomal DNA. Using alkaline denaturation-renaturation, exonuclease III digestion and density gradient centrifugations, covalently closed circular DNA (cc-cDNA) molecules were isolated from 1-, 8-, 16-, and 24-month C57BL/6 mouse heart, brain and liver organs. Restriction enzyme analyses and other enzymatic treatments established the covalently closed nature of the isolated molecules. Electron microscopic analyses of heart eccDNAs showed similar size distributions at all ages, but more discrete size classes and slightly larger circles were observed in 24-month heart eccDNA preparations. Heart contained more circles per cell than either liver or brain, which contained approximately the same amount of eccDNAs per genome. Furthermore, ({sup 3}H)-pBR322 recovery studies revealed no endogenous factors that might have affected the yields of eccDNAs from young and old tissues. To determine if there were any age-related or tissue-specific differences in repetitive sequences in eccDNAs, heart, brain and liver eccDNAs were probed with B1, B2, IAP, L1 and satellite sequences of the mouse genome. The hybridization results showed that these sequence families were differentially represented at all ages in eccDNAs. B2 sequences were the highest in heart, while satellite sequences were the highest in liver and brain. In heart, very little age-related change was observed in the quantity of repetitive sequences. Nevertheless, a tendency to decrease for B1 and B2 sequences at 24 months was observed. In liver, repetitive sequences decreased from 1 to 8 months of age, with very little change beyond that time point. Brain eccDNA repetitive sequences did not change significantly with age.

  20. Extrachromosomal DNA and cell differentiation in cultured pea roots (Pisum sativum)

    SciTech Connect

    Van't Hof, J.

    1986-01-01

    Histological, cytological and molecular analyses of DNA replication and differentiation and meristematic precursors of vascular parenchyma in cultured pea roots show that the initial steps in the transition from a dividing to a differentiated cell involve retardation of DNA replication in late S phase and production of extrachromosomal molecules by excision from late replicating chromosomal DNA. Portions of the extrachromosomal DNA are displaced by a strand displacement mechanism thereby producing free single-stranded molecules. That extrachromosomal molecules have rDNA reflects the fact that in pea roots replication of the ribosomal genes is maximal during late S phase (unpublished results). It is likely, therefore, that the excised late replicating DNA contains some rDNA sequences. 30 refs., 3 figs.

  1. Mismatch repair of heteroduplex DNA intermediates of extrachromosomal recombination in mammalian cells.

    PubMed Central

    Deng, W P; Nickoloff, J A

    1994-01-01

    Previous work indicated that extrachromosomal recombination in mammalian cells could be explained by the single-strand annealing (SSA) model. This model predicts that extrachromosomal recombination leads to nonconservative crossover products and that heteroduplex DNA (hDNA) is formed by annealing of complementary single strands. Mismatched bases in hDNA may subsequently be repaired to wild-type or mutant sequences, or they may remain unrepaired and segregate following DNA replication. We describe a system to examine the formation and mismatch repair of hDNA in recombination intermediates. Our results are consistent with extrachromosomal recombination occurring via SSA and producing crossover recombinant products. As predicted by the SSA model, hDNA was present in double-strand break-induced recombination intermediates. By placing either silent or frameshift mutations in the predicted hDNA region, we have shown that mismatches are efficiently repaired prior to DNA replication. Images PMID:8264607

  2. Cells of pea (Pisum sativum) that differentiate from G2 phase have extrachromosomal DNA

    SciTech Connect

    Van't Hof, J.; Bjerknes, C.A.

    1982-04-01

    Velocity sedimentation in an alkaline sucrose gradient of newly replicated chromosomal DNA revealed the presence of extrachromosomal DNA that was not replicated by differentiating cells in the elongation zone. The extrachromosomal DNA had a number average molecular weight of 12 x 10/sup 6/ to 15 x 10/sup 6/ and a weight average molecular weight of 25 x 10/sup 6/, corresponding to about 26 x 10/sup 6/ and 50 x 10/sup 6/ daltons, respectively, of double-stranded DNA. The molecules were stable, lasting at least 72 h after being formed. Concurrent measurements by velocity sedimentation, autoradiography, and cytophotometry of isolated nuclei indicated that the extrachromosomal molecules were associated with root-tip-cells that stopped dividing and differentiated from G2 phase but not with those that stopped dividing and differentiated from G1 phase.

  3. Reactivation of chromosomally integrated human herpesvirus-6 by telomeric circle formation.

    PubMed

    Prusty, Bhupesh K; Krohne, George; Rudel, Thomas

    2013-01-01

    More than 95% of the human population is infected with human herpesvirus-6 (HHV-6) during early childhood and maintains latent HHV-6 genomes either in an extra-chromosomal form or as a chromosomally integrated HHV-6 (ciHHV-6). In addition, approximately 1% of humans are born with an inheritable form of ciHHV-6 integrated into the telomeres of chromosomes. Immunosuppression and stress conditions can reactivate latent HHV-6 replication, which is associated with clinical complications and even death. We have previously shown that Chlamydia trachomatis infection reactivates ciHHV-6 and induces the formation of extra-chromosomal viral DNA in ciHHV-6 cells. Here, we propose a model and provide experimental evidence for the mechanism of ciHHV-6 reactivation. Infection with Chlamydia induced a transient shortening of telomeric ends, which subsequently led to increased telomeric circle (t-circle) formation and incomplete reconstitution of circular viral genomes containing single viral direct repeat (DR). Correspondingly, short t-circles containing parts of the HHV-6 DR were detected in cells from individuals with genetically inherited ciHHV-6. Furthermore, telomere shortening induced in the absence of Chlamydia infection also caused circularization of ciHHV-6, supporting a t-circle based mechanism for ciHHV-6 reactivation.

  4. The Discovery of Rolling Circle Amplification and Rolling Circle Transcription.

    PubMed

    Mohsen, Michael G; Kool, Eric T

    2016-11-15

    Nucleic acid amplification is a hugely important technology for biology and medicine. While the polymerase chain reaction (PCR) has been highly useful and effective, its reliance on heating and cooling cycles places some constraints on its utility. For example, the heating step of PCR can destroy biological molecules under investigation and heat/cool cycles are not applicable in living systems. Thus, isothermal approaches to DNA and RNA amplification are under widespread study. Perhaps the simplest of these are the rolling circle approaches, including rolling circle amplification (RCA) and rolling circle transcription (RCT). In this strategy, a very small circular oligonucleotide (e.g., 25-100 nucleotides in length) acts as a template for a DNA or an RNA polymerase, producing long repeating product strands that serve as amplified copies of the circle sequence. Here we describe the early developments and studies involving circular oligonucleotides that ultimately led to the burgeoning rolling circle technologies currently under development. This Account starts with our studies on the design of circular oligonucleotides as novel DNA- and RNA-binding motifs. We describe how we developed chemical and biochemical strategies for synthesis of well-defined circular oligonucleotides having defined sequence and open (unpaired) structure, and we outline the unusual ways in which circular DNAs can interact with other nucleic acids. We proceed next to the discovery of DNA and RNA polymerase activity on these very small cyclic DNAs. DNA polymerase "rolling circle" activities were discovered concurrently in our laboratory and that of Andrew Fire. We describe the surprising efficiency of this process even on shockingly small circular DNAs, producing repeating DNAs thousands of nucleotides in length. RNA polymerase activity on circular oligonucleotides was first documented in our group in 1995; especially surprising in this case was the finding that the process occurs efficiently

  5. Recumbent Stone Circles

    NASA Astrophysics Data System (ADS)

    Ruggles, Clive L. N.

    During the 1970s and early 1980s, British archaeoastronomers were striving to bridge the interpretative gulf between the "megalithic observatories" of Alexander Thom and an archaeological mainstream that, generally speaking, was hostile to any mention of astronomy in relation to the megalithic monuments of Neolithic and Early Bronze Age Britain. The Scottish recumbent stone circles (RSCs) came to represent an example where sounder methodology could overcome many of the data selection issues that had beset earlier studies and, with due restraint, produce credible interpretations. Systematic studies of their orientations consistently concluded that the RSCs had a strong lunar connection, and it was widely envisaged that they were the setting for ceremonies associated with the appearance of the moon over the recumbent stone. Other evidence such as the presence of white quartz and the spatial distribution of cupmarks appeared to back up this conclusion. New archaeological investigations since 1999 have challenged and modified these conclusions, confirming in particular that the circles were built to enclose cairns rather than to demarcate open spaces. Yet the restricted pattern of orientations of these structures could only have been achieved by reference to the basic diurnal motions of the skies, and orientation in relation to simple observations of the midsummer moon remains the most likely reading of the alignment evidence taken as a whole. On the other hand, a consideration of the broader context, which includes the nearby Clava cairns, highlights instead the symbolic importance of the sun.

  6. [Willis and his circle].

    PubMed

    van Gijn, Jan; Gijselhart, Joost P

    2012-01-01

    Thomas Willis (1621-1675) grew up in Wiltshire and studied medicine in Oxford, at a time when the city was besieged and then occupied by Parliamentarian troops. He started his career as a country doctor while concurrently taking part in informal gatherings with other scientists (William Petty, Christopher Wren and, later on, Robert Hooke, Richard Lower and Robert Boyle). They performed physical and chemical experiments and carried out a variety of tests on animals. After the restoration of the monarchy in 1660 Willis combined his practice with academic teaching. From then on he focused his studies on the structure and function of the brain, dissecting brains after removal from the skull and fixation in 'spirit of wine'. In his 'Cerebri anatome' of 1664, illustrated by Wren, he drew attention to the arterial circle at the base of the brain, including its physiological advantages. This arterial circle had been incompletely described by others in the past and fully, but only in writing, by Wepfer in 1658.

  7. Identification of regions essential for extrachromosomal replication and maintenance of an endogenous plasmid in Dictyostelium.

    PubMed Central

    Ahern, K G; Howard, P K; Firtel, R A

    1988-01-01

    Initial experiments with the endogenous 12.3 kb Dictyostelium discoideum plasmid Ddp1 led to the generation of a large shuttle vector, Ddp1-20. In addition to Ddp1, this vector contains pBR322 and a gene fusion that confers G418 resistance in Dictyostelium cells. We have shown that Ddp1-20 replicates extrachromosomally in Dictyostelium cells and can be grown in Escherichia coli cells (1). We have now examined deletions within this vector to identify the elements essential for extrachromosomal replication and stable maintenance of the plasmid. We find that a 2.2 kb fragment is sufficient to confer stable, extrachromosomal replication with a reduction in copy number from about 40 to approximately 10-15 copies per cell. Vectors containing additional Ddp1 sequences have a higher copy number. The 2.2 kb region contains none of the complete, previously identified transcription units on Ddp1 expressed during vegetative growth or development. These results suggest that gene products expressed by Ddp1 are not essential for replication, stability, or partitioning of the plasmid between daughter cells. Vectors carrying only the 2.2 kb fragment plus the gene fusion conferring G418 resistance transform Dictyostelium cells with high efficiency using either calcium phosphate mediated transformation or electroporation. Finally, we have examined the relative levels of expression of actin promoters driving neoR genes when in extrachromosomal or integrating vectors. Images PMID:3405751

  8. Talking Circles Promote Equitable Discourse

    ERIC Educational Resources Information Center

    Hung, Marcus

    2015-01-01

    Teachers facilitate math talk in the classroom, but introducing a structured discussion format called the "talking circle" can influence opportunities for equitable student participation. Drawing on his reflections over the 2013-14 academic year and reviewing his detailed teaching notes and lesson plans, Marcus Hung takes a close look at…

  9. Get to Know a Circle

    ERIC Educational Resources Information Center

    Neel-Romine, LeAnn E.; Paul, Sara; Shafer, Kathryn G.

    2012-01-01

    Middle-grades students have a concept image of a circle, but they lack experience in the act of defining. The structure of definitions needs to include conditions that are necessary and sufficient. Most students are able to identify necessary conditions, but they have trouble determining if sufficient conditions are met. How do teachers engage…

  10. The Vertical Structure, Ionization, and Kinematic Structure of Spiral Arm Outflows Inside and Outside the Solar Circle

    NASA Astrophysics Data System (ADS)

    Gostisha, Martin; Benjamin, R. A.; Haffner, L. M.; Hill, A. S.; Barger, K. A.

    2013-06-01

    Velocity-resolved surveys of the Galactic plane with the Wisconsin H-alpha Mapper indicate a thick distribution of ~1 kpc for the ionized gas layer of the Galaxy, but also show that the emission is enhanced in the vicinity of spiral arms. We characterize the vertical scale-heights of the Perseus Arm and Scutum-Centaurus Arm as a function of azimuth and compare the structure of these arms in ionized gas (from WHAM) and neutral gas (from the Leiden-Argentina-Bonn survey). We then explore the hypothesis that these arms are the sources of correlated outflow from the Galactic disk and compare the observed velocity structure of the arms with different predictions for outflow kinematics.

  11. The Women's Circle comes full circle.

    PubMed

    Saylors, Karen

    2003-01-01

    Women have been the backbone of service provision for health and healing in the Native American community in the San Francisco Bay Area. The contributions of Native women are exemplified in the Women's Circle of the Native American Health Centers in San Francisco and Oakland. Women receive a broad range of services through the Women's Circle--in a coed residential substance abuse treatment facility (Friendship House), in groups, in one-on-one counseling, and at the Friendship House American Indian Lodge, a residential women and children's facility in Oakland. This article will look at lessons learned, using both quantitative outcome measures and ethnographic means to examine the impact of the Women's Circle and how the circle was completed. Program staff were interviewed to gain insight into how the program impacted female clients. The article juxtaposes the program elements clients identified as important to their healing and staff's perceptions about the growth of the program. Distinct women's health issues--physical, emotional, mental and spiritual-sculpted program development. Significant findings and lifestyle changes that occurred around involvement in the Women's Circle are examined.

  12. Literature Circles: Getting Started.

    ERIC Educational Resources Information Center

    Fink, Lisa

    Literature Circles are a great way to supplement a reading program in a literature-based classroom. In this lesson plan, students create and answer comprehension questions, discover new vocabulary, and examine elements of literature. The students feel ownership in Literature Circles, because they are responsible for the meeting. Any genre of…

  13. Polygons and Their Circles

    ERIC Educational Resources Information Center

    Stephenson, Paul

    2009-01-01

    In order to find its circumference, Archimedes famously boxed the circle between two polygons. Ending the first of a series of articles (MT179) with an aside, Francis Lopez-Real reverses the situation to ask: Which polygons can be boxed between two circles? (The official term for such polygons is "bicentric".) The sides of these polygons are…

  14. Polygons and Their Circles

    ERIC Educational Resources Information Center

    Stephenson, Paul

    2009-01-01

    In order to find its circumference, Archimedes famously boxed the circle between two polygons. Ending the first of a series of articles (MT179) with an aside, Francis Lopez-Real reverses the situation to ask: Which polygons can be boxed between two circles? (The official term for such polygons is "bicentric".) The sides of these polygons are…

  15. Kaposi's sarcoma-associated herpesvirus stably clusters its genomes across generations to maintain itself extrachromosomally.

    PubMed

    Chiu, Ya-Fang; Sugden, Arthur U; Fox, Kathryn; Hayes, Mitchell; Sugden, Bill

    2017-09-04

    Genetic elements that replicate extrachromosomally are rare in mammals; however, several human tumor viruses, including the papillomaviruses and the gammaherpesviruses, maintain their plasmid genomes by tethering them to cellular chromosomes. We have uncovered an unprecedented mechanism of viral replication: Kaposi's sarcoma-associated herpesvirus (KSHV) stably clusters its genomes across generations to maintain itself extrachromosomally. To identify and characterize this mechanism, we developed two complementary, independent approaches: live-cell imaging and a predictive computational model. The clustering of KSHV requires the viral protein, LANA1, to bind viral genomes to nucleosomes arrayed on both cellular and viral DNA. Clustering affects both viral partitioning and viral genome numbers of KSHV. The clustering of KSHV plasmids provides it with an effective evolutionary strategy to rapidly increase copy numbers of genomes per cell at the expense of the total numbers of cells infected. © 2017 Chiu et al.

  16. Epigenetic Repeat-Induced Gene Silencing in the Chromosomal and Extrachromosomal Contexts in Human Cells

    PubMed Central

    Mitsuda, Sho-hei; Shimizu, Noriaki

    2016-01-01

    A plasmid bearing both a replication initiation region and a matrix attachment region is spontaneously amplified in transfected mammalian cells and generates plasmid repeats in the extrachromosomal double minutes (DMs) or the chromosomal homogeneously staining region (HSR). Generally, the repeat sequences are subject to repeat-induced gene silencing, the mechanism of which remains to be elucidated. Previous research showed that gene expression from the same plasmid repeat was higher from repeats located at DMs than at the HSR, which may reflect the extrachromosomal environment of the DMs. In the current study, plasmid repeats in both DMs and HSR were associated with repressive histone modifications (H3K9me3, H3K9me2), and the levels of repressive chromatin markers were higher in HSR than in DMs. Inactive chromatin is known to spread to neighboring regions in chromosome arm. Here, we found that such spreading also occurs in extrachromosomal DMs. Higher levels of active histone modifications (H3K9Ac, H3K4me3, and H3K79me2) were detected at plasmid repeats in DMs than in HSR. The level of DNA CpG methylation was generally low in both DMs and HSR; however, there were some hypermethylated copies within the population of repeated sequences, and the frequency of such copies was higher in DMs than in HSR. Together, these data suggest a “DNA methylation-core and chromatin-spread” model for repeat-induced gene silencing. The unique histone modifications at the extrachromosomal context are discussed with regard to the model. PMID:27525955

  17. Extrachromosomal DNA of pea (Pisum sativum) root-tip cells replicates by strand displacement

    SciTech Connect

    Krimer, D.B.; Van't Hof, J.

    1983-04-01

    In cultured pea roots there is extrachromosomal DNA associated with cells that differentiate from the G/sub 2/ phase of the cell cycle that is absent from those that differentiate from the G/sub 1/ phase. The authors examined this extrachromosomal DNA by electron microscopy and found that it consisted of three types: (i) double-stranded linear molecules with single-stranded branches (74%), (ii) double-stranded molecules without branches (26%), and (iii) free single-stranded molecules. The double-stranded molecules with or without branches were similar in length, having a modal length of 10-15 ..mu..m. The free single-stranded molecules were shorter and had a mean length of 3.8 ..mu..m. The length of the branches attached to the duplex molecules was only slightly less than that of the free form. The duplex molecules with branches were interpreted as configurations reflecting an ongoing strand-displacement process that results in free single-stranded molecules. Finally, measurements on duplex molecules with multiple branches suggested that the extrachromosomal DNA may exist in the form of tandemly repeated sequences. 8 references, 8 figures.

  18. Regulated expression of the feline panleukopenia virus P38 promoter on extrachromosomal FPV/EBV chimeric plasmids.

    PubMed Central

    Clemens, D L; Carlson, J O

    1989-01-01

    Feline panleukopenia virus/Epstein-Barr virus (FPV/EBV) chimeric expression plasmids were constructed to study regulation of the structural protein gene of the parvovirus, FPV, in a homologous cell culture system. Detection and quantitation of activity from the native FPV promoter, P38, was facilitated by fusing the Escherichia coli lacZ gene with the FPV structural protein gene. Feline cell lines which stably maintained these plasmids extrachromosomally were established. Constitutive beta-galactosidase activity was low but increased up to 40-fold after infection with FPV. Expression of beta-galactosidase was only detected when the FPV/lacZ gene was oriented in the same transcriptional direction as the Epstein-Barr virus gene coding for EBNA-1. When a small open reading frame upstream of the FPV/lacZ initiation codon was deleted, beta-galactosidase expression increased another 4.7- to 26-fold. These changes in beta-galactosidase activity indicate that expression of the FPV structural protein gene is regulated both transcriptionally and posttranscriptionally. Images PMID:2542586

  19. Kinematic Structures for Processing of Surfaces with a Circle Directrix and a Straight Line Generatrix (Part IV)

    NASA Astrophysics Data System (ADS)

    Cioară, R.

    2016-11-01

    A body with a given geometry can be obtained by various manufacturing procedures, entailing, however, different surface quality, dimensional precision and (most importantly) productivity. Each body is characterised by one or more surfaces, simple or complex, as the case may be. It is known that a surface is characterised by a directrix and a generatrix, as well as by the modality of its physical achievement by means of the machines and tools uses for manufacturing. The directrix is obtained as a result of a primary motion and possibly one or more secondary motions. The generatrix is obtained as a result of one secondary motion, rarely more. If the generatrix is materialized on a tool, then a secondary motion is not necessary. In addition one or more auxiliary motions are needed. Other generation modalities not excluded, from the theory of surface generation on machine-tools it is known that the directrix, as well as the generatrix can be: materialized; generated by copying; kinematically generated as the trajectory of a point; kinematically generated as the envelope of a family of curves; generated by rolling; or programmed. Typically in literature generation “by copying” and “programmed generation” of the directrix and generatrix are not addressed distinctively, both being assumed as of the same nature. The recent evolution of industrial electronics and implicitly of machine-tools has determined a clear differentiation between the kinematics and construction of machine-tools (still) using generation by copying from a master and the kinematics of NC machine-tools. The paper is one of kinematic synthesis, oriented towards innovation-invention, and presents by means of examples, not necessarily known or typical, all six cases of generation of surfaces characterised by a straight line generatrix and a circle directrix obtained kinematically as the envelope of a family of curves.

  20. Beyond the Chromosome: The Prevalence of Unique Extra-Chromosomal Bacteriophages with Integrated Virulence Genes in Pathogenic Staphylococcus aureus

    PubMed Central

    Utter, Bryan; Deutsch, Douglas R.; Schuch, Raymond; Winer, Benjamin Y.; Verratti, Kathleen; Bishop-Lilly, Kim; Sozhamannan, Shanmuga; Fischetti, Vincent A.

    2014-01-01

    In Staphylococcus aureus, the disease impact of chromosomally integrated prophages on virulence is well described. However, the existence of extra-chromosomal prophages, both plasmidial and episomal, remains obscure. Despite the recent explosion in bacterial and bacteriophage genomic sequencing, studies have failed to specifically focus on extra-chromosomal elements. We selectively enriched and sequenced extra-chromosomal DNA from S. aureus isolates using Roche-454 technology and uncovered evidence for the widespread distribution of multiple extra-chromosomal prophages (ExPΦs) throughout both antibiotic-sensitive and -resistant strains. We completely sequenced one such element comprised of a 43.8 kbp, circular ExPΦ (designated ФBU01) from a vancomycin-intermediate S. aureus (VISA) strain. Assembly and annotation of ФBU01 revealed a number of putative virulence determinants encoded within a bacteriophage immune evasion cluster (IEC). Our identification of several potential ExPΦs and mobile genetic elements (MGEs) also revealed numerous putative virulence factors and antibiotic resistance genes. We describe here a previously unidentified level of genetic diversity of stealth extra-chromosomal elements in S. aureus, including phages with a larger presence outside the chromosome that likely play a prominent role in pathogenesis and strain diversity driven by horizontal gene transfer (HGT). PMID:24963913

  1. Quantization on the circle

    NASA Astrophysics Data System (ADS)

    Merad, M.

    2006-05-01

    We present, via the path-integral approach, the quantum study of a particle without spin constrained to move on a circle and subjected to the action of an external field (V, A). In the first stage, we follow the Faddeev-Senjanovic constraints technique that is essentially based on the Dirac algorithm; and in the second stage, we use the path-integral coherent state relative to the circle, compatible with the topological properties. In the two cases, the free particle and the problem of the magnetic field are shown as an illustrative calculation.

  2. Literature Circles Go Digital

    ERIC Educational Resources Information Center

    Bromley, Karen; Faughnan, Michelle; Ham, Susan; Miller, Melissa; Armstrong, Traci; Crandall, Cassandra; Garrison, Julia; Marrone, Nicholas

    2014-01-01

    This article describes a literature circle of seven pre-service teacher education students who read "Al Capone Shines My Shoes" (G. Choldenko, 2009). Students used the Internet to complete their roles, shared what they learned as they discussed the book, and then wrote about the digital experience. Four themes emerged from an analysis of…

  3. Differentiating through Literature Circles

    ERIC Educational Resources Information Center

    Helgeson, John

    2017-01-01

    This article begins with an example of a typical middle-school experience with literature circles. Students read a common text and come prepared to share and discuss the text based on individual roles they are assigned. Teachers are using this practice to address the complexity levels of texts in order to help students develop the skills they need…

  4. Differentiating through Literature Circles

    ERIC Educational Resources Information Center

    Helgeson, John

    2017-01-01

    This article begins with an example of a typical middle-school experience with literature circles. Students read a common text and come prepared to share and discuss the text based on individual roles they are assigned. Teachers are using this practice to address the complexity levels of texts in order to help students develop the skills they need…

  5. Review: The Closing Circle

    ERIC Educational Resources Information Center

    Environment, 1972

    1972-01-01

    Two views of prominent biologists are presented side-by-side. Focal point is Barry Commoner's book, The Closing Circle, with a subsequent review by Paul Ehrlich. Growth of population, increases in affluence, and increased pollution from products of technology are considered. (BL)

  6. Circles Inscribed in Rhombuses

    ERIC Educational Resources Information Center

    Srinivasan, V.K.

    2013-01-01

    In this teaching oriented article, I am introducing the concept of an equilateral rhombus, which is completely characterized. Three main theorems are given with proofs in Section 2. Most of the time, the rhombuses that are discussed are not squares. For a given circle of a specified radius sigma greater than?0, there is exactly one equilateral…

  7. Circling "the Scourge"

    ERIC Educational Resources Information Center

    Keller, Bess

    2005-01-01

    In Kenya alone, where the infection rate is estimated to have reached 13 percent of the population, 27,000 teachers will die and more than 2 million children will lose one or both parents to AIDS in the next five years. The Kenyan project uses "study circles," in which teachers learn together about HIV, script new sexual behaviors for…

  8. Why Story Circle Matters

    ERIC Educational Resources Information Center

    Lyon, George Ella

    2016-01-01

    If adult attention is screen scrambled, what about kids, whose brains are still developing? In a world where we are over stimulated and hyperlinked-in we are deprived of the kind of time with a person or experience that deepens and sustains us. Here, poet laureate George Ella Lyon writes that the story circle can be such an experience. A school…

  9. The Circle of Collaboration.

    ERIC Educational Resources Information Center

    Burnham, Jacki; Discher, Stephanie; Ingle, Krista

    This brief paper describes the Circle of Collaboration approach at one elementary school in Utah that is focusing on development of an inclusive school for all students and implementation of a program (Balance Literacy) to enhance students' reading skills. Balance Literacy incorporates phonemic awareness, phonic instruction, fluency, vocabulary,…

  10. Why Story Circle Matters

    ERIC Educational Resources Information Center

    Lyon, George Ella

    2016-01-01

    If adult attention is screen scrambled, what about kids, whose brains are still developing? In a world where we are over stimulated and hyperlinked-in we are deprived of the kind of time with a person or experience that deepens and sustains us. Here, poet laureate George Ella Lyon writes that the story circle can be such an experience. A school…

  11. Breaking the Sacred Circle.

    ERIC Educational Resources Information Center

    Bill, Willard E.

    Intended as a basis for student discussions on American Indian issues, this article provides background on American Indian and Alaskan Native spiritual values and the white man's disruption of the Sacred Circle of Life. The foundation of the philosophies of North American indigenous peoples was the idea of cyclical reaffirmation and the goal of…

  12. Inside Larry's Circle

    ERIC Educational Resources Information Center

    Arnold, Alice

    2009-01-01

    Last spring, students from several North Carolina middle schools were invited to participate in the annual Celebrate the Arts festival in Columbus Country. Larry Hewett, a local art teacher, had been selected to instruct the middle-school students. Larry's River Rock Circles project was made as the starting point for the Celebrate the Arts…

  13. The Circle of Discrimination:

    ERIC Educational Resources Information Center

    Bloch, Herman D.

    1976-01-01

    Extends previous studies dealing with the socioeconomic subordination of Blacks. Thesis is that within the circle of discrimination there are cycles, within of which is a germinated seed that forms a subsequent cycle, and the process goes on and on; the pattern becomes self-generative. (Author/AM)

  14. Circles Inscribed in Rhombuses

    ERIC Educational Resources Information Center

    Srinivasan, V.K.

    2013-01-01

    In this teaching oriented article, I am introducing the concept of an equilateral rhombus, which is completely characterized. Three main theorems are given with proofs in Section 2. Most of the time, the rhombuses that are discussed are not squares. For a given circle of a specified radius sigma greater than?0, there is exactly one equilateral…

  15. Literature Circles in ELT

    ERIC Educational Resources Information Center

    Shelton-Strong, Scott J.

    2012-01-01

    While the intrinsic value of reading extensively for L2 learners has rarely been questioned, practicalities of implementation and the existence of gains beyond lexical enrichment have generated discussion. This article outlines and explores the benefits which Literature Circles (LCs) offer to English language learning and attempts to identify…

  16. Japanese Quality Control Circles.

    ERIC Educational Resources Information Center

    Nishiyama, Kazuo

    In recent years, United States scholars with an interest in international business and organizational communication have begun to notice the success of Japanese "quality control circles." These are small groups, usually composed of seven to ten workers, who are organized at the production levels within most large Japanese factories. A…

  17. Circling "the Scourge"

    ERIC Educational Resources Information Center

    Keller, Bess

    2005-01-01

    In Kenya alone, where the infection rate is estimated to have reached 13 percent of the population, 27,000 teachers will die and more than 2 million children will lose one or both parents to AIDS in the next five years. The Kenyan project uses "study circles," in which teachers learn together about HIV, script new sexual behaviors for…

  18. Going Round in Circles

    ERIC Educational Resources Information Center

    Clausen-May, Tandi

    2006-01-01

    In this article, the author describes two Powerpoint presentations designed to help visual learners calculate the circumference and the area of a circle. In particular, the author describes how these presentations can be used to establish mental images that can help pupils to understand, and so recall, the principles that underlie the formulae for…

  19. Inside Larry's Circle

    ERIC Educational Resources Information Center

    Arnold, Alice

    2009-01-01

    Last spring, students from several North Carolina middle schools were invited to participate in the annual Celebrate the Arts festival in Columbus Country. Larry Hewett, a local art teacher, had been selected to instruct the middle-school students. Larry's River Rock Circles project was made as the starting point for the Celebrate the Arts…

  20. Review: The Closing Circle

    ERIC Educational Resources Information Center

    Environment, 1972

    1972-01-01

    Two views of prominent biologists are presented side-by-side. Focal point is Barry Commoner's book, The Closing Circle, with a subsequent review by Paul Ehrlich. Growth of population, increases in affluence, and increased pollution from products of technology are considered. (BL)

  1. Formation of Extrachromosomal Circular DNA from Long Terminal Repeats of Retrotransposons in Saccharomyces cerevisiae.

    PubMed

    Møller, Henrik D; Larsen, Camilla E; Parsons, Lance; Hansen, Anders Johannes; Regenberg, Birgitte; Mourier, Tobias

    2015-12-17

    Extrachromosomal circular DNA (eccDNA) derived from chromosomal Ty retrotransposons in yeast can be generated in multiple ways. Ty eccDNA can arise from the circularization of extrachromosomal linear DNA during the transpositional life cycle of retrotransposons, or from circularization of genomic Ty DNA. Circularization may happen through nonhomologous end-joining (NHEJ) of long terminal repeats (LTRs) flanking Ty elements, by Ty autointegration, or by LTR-LTR recombination. By performing an in-depth investigation of sequence reads stemming from Ty eccDNAs obtained from populations of Saccharomyces cerevisiae S288c, we find that eccDNAs predominantly correspond to full-length Ty1 elements. Analyses of sequence junctions reveal no signs of NHEJ or autointegration events. We detect recombination junctions that are consistent with yeast Ty eccDNAs being generated through recombination events within the genome. This opens the possibility that retrotransposable elements could move around in the genome without an RNA intermediate directly through DNA circularization.

  2. Unstable amplification of two extrachromosomal elements in alpha-difluoromethylornithine-resistant Leishmania donovani.

    PubMed Central

    Hanson, S; Beverley, S M; Wagner, W; Ullman, B

    1992-01-01

    We describe the first example of unstable gene amplification consisting of linear extrachromosomal DNAs in drug-resistant eukaryotic cells. alpha-Difluoromethylornithine (DFMO)-resistant Leishmania donovani with an amplified ornithine decarboxylase (ODC) gene copy number contained two new extrachromosomal DNAs, both present in 10 to 20 copies. One of these was a 140-kb linear DNA (ODC140-L) on which all of the amplified copies of the odc gene were located. The second was a 70-kb circular DNA (ODC70-C) containing an inverted repeat but lacking the odc gene. Both ODC140-L and ODC70-C were derived from a preexisting wild-type chromosome, probably by a conservative amplification mechanism. Both elements were unstable in the absence of DFMO, and their disappearance coincided with a decrease in ODC activity and an increase in DFMO growth sensitivity. These results suggest the possibility that ODC70-C may play a role in DFMO resistance. These data expand the diversity of known amplification mechanisms in eukaryotes to include the simultaneous unstable amplification of both linear and circular DNAs. Further characterization of these molecules will provide insights into the molecular mechanisms underlying gene amplification, including the ability of linear amplified DNAs to acquire telomeres and the determinants of chromosomal stability. Images PMID:1448081

  3. VIEW DOWN BIRCH CIRCLE FROM CORNER OF BIRCH CIRCLE AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW DOWN BIRCH CIRCLE FROM CORNER OF BIRCH CIRCLE AND ELM DRIVE. VIEW FACING SOUTHWEST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  4. Training Needs of Quality Circles.

    ERIC Educational Resources Information Center

    Smeltzer, Larry R.; Kedia, Ben L.

    1987-01-01

    Quality circle training has been adapted from Japan, but United States training needs are very different. A survey of quality circle members indicated they perceived human relations skills to be significantly more important than problem-analysis skills. (CH)

  5. A Round Is a Circle...

    ERIC Educational Resources Information Center

    Boyarsky, Terry L.

    2006-01-01

    Circles are everywhere and endlessly intriguing. We know, sense, and feel them in time, space, sound, and the cycles of nature. A person's life contains spirals, repetitions, going out and coming back. Poets write of circles; composers write song cycles. Circles are at the root of the curriculum, concepts deep yet accessible, infinite in their…

  6. A Round Is a Circle...

    ERIC Educational Resources Information Center

    Boyarsky, Terry L.

    2006-01-01

    Circles are everywhere and endlessly intriguing. We know, sense, and feel them in time, space, sound, and the cycles of nature. A person's life contains spirals, repetitions, going out and coming back. Poets write of circles; composers write song cycles. Circles are at the root of the curriculum, concepts deep yet accessible, infinite in their…

  7. Bacteria swimming in circles

    NASA Astrophysics Data System (ADS)

    Lauga, Eric; Diluzio, Willow; Garstecki, Piotr; Whitesides, George; Stone, Howard

    2004-11-01

    The bacteria E.coli, which lives in our stomach, swims in a viscous fluid by rotating its flagella together in a helical bundle. The rotation is due to the action of rotary motors embedded in the cell wall. Motivated by experimental observations (Frymier et al., 1995, PNAS vol. 92), as well as our own extensive experiments, that bacteria near solid surfaces do not swim in a straight line but swim in circles, we present a mechanical model for a swimming microorganism near a solid boundary. We show that the combination of a rotating helical bundle and a solid boundary leads to a circular motion to the right of the bacterium (as viewed from above), in accordance with experimental observations. Values of the radii of the circle and the rotation rate are predicted and compared with experimental data.

  8. Black Pine Circle Project

    SciTech Connect

    Mytko, Christine

    2014-03-31

    A group of seventh graders from Black Pine Circle school in Berkeley had the opportunity to experience the Advanced Light Source (ALS) as "users" via a collaborative field trip and proposal project. The project culminated with a field trip to the ALS for all seventh graders, which included a visit to the ALS data visualization room, a diffraction demonstration, a beamline tour, and informative sessions about x-rays and tomography presented by ALS scientists.

  9. Black Pine Circle Project

    ScienceCinema

    Mytko, Christine

    2016-07-12

    A group of seventh graders from Black Pine Circle school in Berkeley had the opportunity to experience the Advanced Light Source (ALS) as "users" via a collaborative field trip and proposal project. The project culminated with a field trip to the ALS for all seventh graders, which included a visit to the ALS data visualization room, a diffraction demonstration, a beamline tour, and informative sessions about x-rays and tomography presented by ALS scientists.

  10. Visualization and quantitative analysis of extrachromosomal telomere-repeat DNA in individual human cells by Halo-FISH.

    PubMed

    Komosa, Martin; Root, Heather; Meyn, M Stephen

    2015-02-27

    Current methods for characterizing extrachromosomal nuclear DNA in mammalian cells do not permit single-cell analysis, are often semi-quantitative and frequently biased toward the detection of circular species. To overcome these limitations, we developed Halo-FISH to visualize and quantitatively analyze extrachromosomal DNA in single cells. We demonstrate Halo-FISH by using it to analyze extrachromosomal telomere-repeat (ECTR) in human cells that use the Alternative Lengthening of Telomeres (ALT) pathway(s) to maintain telomere lengths. We find that GM847 and VA13 ALT cells average ∼80 detectable G/C-strand ECTR DNA molecules/nucleus, while U2OS ALT cells average ∼18 molecules/nucleus. In comparison, human primary and telomerase-positive cells contain <5 ECTR DNA molecules/nucleus. ECTR DNA in ALT cells exhibit striking cell-to-cell variations in number (<20 to >300), range widely in length (<1 to >200 kb) and are composed of primarily G- or C-strand telomere-repeat DNA. Halo-FISH enables, for the first time, the simultaneous analysis of ECTR DNA and chromosomal telomeres in a single cell. We find that ECTR DNA comprises ∼15% of telomere-repeat DNA in GM847 and VA13 cells, but <4% in U2OS cells. In addition to its use in ALT cell analysis, Halo-FISH can facilitate the study of a wide variety of extrachromosomal DNA in mammalian cells.

  11. Visualization and quantitative analysis of extrachromosomal telomere-repeat DNA in individual human cells by Halo-FISH

    PubMed Central

    Komosa, Martin; Root, Heather; Meyn, M. Stephen

    2015-01-01

    Current methods for characterizing extrachromosomal nuclear DNA in mammalian cells do not permit single-cell analysis, are often semi-quantitative and frequently biased toward the detection of circular species. To overcome these limitations, we developed Halo-FISH to visualize and quantitatively analyze extrachromosomal DNA in single cells. We demonstrate Halo-FISH by using it to analyze extrachromosomal telomere-repeat (ECTR) in human cells that use the Alternative Lengthening of Telomeres (ALT) pathway(s) to maintain telomere lengths. We find that GM847 and VA13 ALT cells average ∼80 detectable G/C-strand ECTR DNA molecules/nucleus, while U2OS ALT cells average ∼18 molecules/nucleus. In comparison, human primary and telomerase-positive cells contain <5 ECTR DNA molecules/nucleus. ECTR DNA in ALT cells exhibit striking cell-to-cell variations in number (<20 to >300), range widely in length (<1 to >200 kb) and are composed of primarily G- or C-strand telomere-repeat DNA. Halo-FISH enables, for the first time, the simultaneous analysis of ECTR DNA and chromosomal telomeres in a single cell. We find that ECTR DNA comprises ∼15% of telomere-repeat DNA in GM847 and VA13 cells, but <4% in U2OS cells. In addition to its use in ALT cell analysis, Halo-FISH can facilitate the study of a wide variety of extrachromosomal DNA in mammalian cells. PMID:25662602

  12. Metabolic stability of the extrachromosomal ribosomal RNA genes in the slime mould Physarum polycephalum.

    PubMed

    Hall, L; Gubler, U; Braun, R

    1978-05-01

    The rRNA genes of the slime mould Physarum polycephalum are located on free, linear DNA molecules of a discrete size, Mr=38X10(6). Using an isotope dilution technique we have examined the metabolic stability of these extrachromosomal genes during active, balanced growth. Microplasmodia, prelabelled with [3H]thymidine, were used to prepare synchronous surface plasmodial cultures which were subsequently grown on unlabelled medium. The gross synthesis of ribosomal DNA was then determined over three consecutive mitotic divisions from the ratio of 3H to 14C in a hybrid formed between the extracted ribosomal [3H]DNA and a [14C]rRNA probe. It was found that ribosomal DNA, like chromosomal DNA, is completely stable during active growth.

  13. Nonselective Persistence of a Rickettsia conorii Extrachromosomal Plasmid during Mammalian Infection

    PubMed Central

    Riley, Sean P.; Fish, Abigail I.; Garza, Daniel A.; Banajee, Kaikhushroo H.; Harris, Emma K.; del Piero, Fabio

    2016-01-01

    Scientific analysis of the genus Rickettsia is undergoing a rapid period of change with the emergence of viable genetic tools. The development of these tools for the mutagenesis of pathogenic bacteria will permit forward genetic analysis of Rickettsia pathogenesis. Despite these advances, uncertainty still remains regarding the use of plasmids to study these bacteria in in vivo mammalian models of infection, namely, the potential for virulence changes associated with the presence of extrachromosomal DNA and nonselective persistence of plasmids in mammalian models of infection. Here, we describe the transformation of Rickettsia conorii Malish 7 with the plasmid pRam18dRGA[AmTrCh]. Transformed R. conorii stably maintains this plasmid in infected cell cultures, expresses the encoded fluorescent proteins, and exhibits growth kinetics in cell culture similar to those of nontransformed R. conorii. Using a well-established murine model of fatal Mediterranean spotted fever, we demonstrate that R. conorii(pRam18dRGA[AmTrCh]) elicits the same fatal outcomes in animals as its untransformed counterpart and, importantly, maintains the plasmid throughout infection in the absence of selective antibiotic pressure. Interestingly, plasmid-transformed R. conorii was readily observed both in endothelial cells and within circulating leukocytes. Together, our data demonstrate that the presence of an extrachromosomal DNA element in a pathogenic rickettsial species does not affect either in vitro proliferation or in vivo infectivity in models of disease and that plasmids such as pRam18dRGA[AmTrCh] are valuable tools for the further genetic manipulation of pathogenic rickettsiae. PMID:26755154

  14. Characterization of Rhizobium grahamii extrachromosomal replicons and their transfer among rhizobia.

    PubMed

    Althabegoiti, María Julia; Ormeño-Orrillo, Ernesto; Lozano, Luis; Torres Tejerizo, Gonzalo; Rogel, Marco Antonio; Mora, Jaime; Martínez-Romero, Esperanza

    2014-01-08

    Rhizobium grahamii belongs to a new phylogenetic group of rhizobia together with Rhizobium mesoamericanum and other species. R. grahamii has a broad-host-range that includes Leucaena leucocephala and Phaseolus vulgaris, although it is a poor competitor for P. vulgaris nodulation in the presence of Rhizobium etli or Rhizobium phaseoli strains. This work analyzed the genome sequence and transfer properties of R. grahamii plasmids. Genome sequence was obtained from R. grahamii CCGE502 type strain isolated from Dalea leporina in Mexico. The CCGE502 genome comprises one chromosome and two extrachromosomal replicons (ERs), pRgrCCGE502a and pRgrCCGE502b. Additionally, a plasmid integrated in the CCGE502 chromosome was found. The genomic comparison of ERs from this group showed that gene content is more variable than average nucleotide identity (ANI). Well conserved nod and nif genes were found in R. grahamii and R. mesoamericanum with some differences. R. phaseoli Ch24-10 genes expressed in bacterial cells in roots were found to be conserved in pRgrCCGE502b. Regarding conjugative transfer we were unable to transfer the R. grahamii CCGE502 symbiotic plasmid and its megaplasmid to other rhizobial hosts but we could transfer the symbiotic plasmid to Agrobacterium tumefaciens with transfer dependent on homoserine lactones. Variable degrees of nucleotide identity and gene content conservation were found among the different R. grahamii CCGE502 replicons in comparison to R. mesoamericanum genomes. The extrachromosomal replicons from R. grahamii were more similar to those found in phylogenetically related Rhizobium species. However, limited similarities of R. grahamii CCGE502 symbiotic plasmid and megaplasmid were observed in other more distant Rhizobium species. The set of conserved genes in R. grahamii comprises some of those that are highly expressed in R. phaseoli on plant roots, suggesting that they play an important role in root colonization.

  15. Characterization of Rhizobium grahamii extrachromosomal replicons and their transfer among rhizobia

    PubMed Central

    2014-01-01

    Background Rhizobium grahamii belongs to a new phylogenetic group of rhizobia together with Rhizobium mesoamericanum and other species. R. grahamii has a broad-host-range that includes Leucaena leucocephala and Phaseolus vulgaris, although it is a poor competitor for P. vulgaris nodulation in the presence of Rhizobium etli or Rhizobium phaseoli strains. This work analyzed the genome sequence and transfer properties of R. grahamii plasmids. Results Genome sequence was obtained from R. grahamii CCGE502 type strain isolated from Dalea leporina in Mexico. The CCGE502 genome comprises one chromosome and two extrachromosomal replicons (ERs), pRgrCCGE502a and pRgrCCGE502b. Additionally, a plasmid integrated in the CCGE502 chromosome was found. The genomic comparison of ERs from this group showed that gene content is more variable than average nucleotide identity (ANI). Well conserved nod and nif genes were found in R. grahamii and R. mesoamericanum with some differences. R. phaseoli Ch24-10 genes expressed in bacterial cells in roots were found to be conserved in pRgrCCGE502b. Regarding conjugative transfer we were unable to transfer the R. grahamii CCGE502 symbiotic plasmid and its megaplasmid to other rhizobial hosts but we could transfer the symbiotic plasmid to Agrobacterium tumefaciens with transfer dependent on homoserine lactones. Conclusion Variable degrees of nucleotide identity and gene content conservation were found among the different R. grahamii CCGE502 replicons in comparison to R. mesoamericanum genomes. The extrachromosomal replicons from R. grahamii were more similar to those found in phylogenetically related Rhizobium species. However, limited similarities of R. grahamii CCGE502 symbiotic plasmid and megaplasmid were observed in other more distant Rhizobium species. The set of conserved genes in R. grahamii comprises some of those that are highly expressed in R. phaseoli on plant roots, suggesting that they play an important role in root colonization

  16. Time to Circle Up: Using Morning Meeting in Professional Development

    ERIC Educational Resources Information Center

    Bornstein, Jodi; Bradley, Jennifer

    2007-01-01

    Most teachers of young children start their days with some type of class meeting--typically circle time. Although similar to circle time, Morning Meeting is structured with four essential components: the greeting (children greet each other); sharing (several children share important information about themselves); a group activity (the group…

  17. Circle of Ashes

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Circle of Ashes

    This plot tells astronomers that a pulsar, the remnant of a stellar explosion, is surrounded by a disk of its own ashes. The disk, revealed by the two data points at the far right from NASA's Spitzer Space Telescope, is the first ever found around a pulsar. Astronomers believe planets might rise up out of these stellar ashes.

    The data in this plot, or spectrum, were taken by ground-based telescopes and Spitzer. They show that light from around the pulsar can be divided into two categories: direct light from the pulsar, and light from the dusty disk swirling around the pulsar. This excess light was detected by Spitzer's infrared array camera. Dust gives off more infrared light than the pulsar because it's cooler.

    The pulsar, called 4U 0142+61, was once a massive star, until about 100,000 years ago, when it blew up in a supernova explosion and scattered dusty debris into space. Some of that debris was captured into what astronomers refer to as a 'fallback disk,' now circling the leftover stellar core, or pulsar. The disk resembles protoplanetary disks around young stars, out of which planets are thought to be born.

    The data have been corrected to remove the effects of light scattering from dust that lies between Earth and the pulsar.

    The ground-based data is from the Keck I telescope atop Mauna Kea, Hawaii.

  18. Introducing Healing Circles and Talking Circles into Primary Care

    PubMed Central

    Mehl-Madrona, Lewis; Mainguy, Barbara

    2014-01-01

    We report on the incorporation of a North American aboriginal procedure called “the talking circle” into primary care in areas serving this population. Communication is regulated through the passing of a talking piece (an object of special meaning or symbolism to the circle facilitator, who is usually called the circle keeper). Twelve hundred people participated in talking circles in which 415 attended 4 sessions and completed pre- and postquestionnaires. Outcome measures included baseline and end Measure Your Medical Outcome Profile version 2 forms. Participation in at least 4 talking circles resulted in a statistically significant improvement in reported symptoms and overall quality of life (p < 0.001 and effect sizes ranging from 0.75 to 1.19). The talking circle is a useful tool to use with Native Americans. It may be useful as a means to reduce health care costs by providing other alternative settings to deal with stress-related and other life problems. PMID:24867544

  19. Control of telomere length by a trimming mechanism that involves generation of t-circles

    PubMed Central

    Pickett, Hilda A; Cesare, Anthony J; Johnston, Rebecca L; Neumann, Axel A; Reddel, Roger R

    2009-01-01

    Telomere lengths are maintained in many cancer cells by the ribonucleoprotein enzyme telomerase but can be further elongated by increasing telomerase activity through the overexpression of telomerase components. We report here that increased telomerase activity results in increased telomere length that eventually reaches a plateau, accompanied by the generation of telomere length heterogeneity and the accumulation of extrachromosomal telomeric repeat DNA, principally in the form of telomeric circles (t-circles). Telomeric DNA was observed in promyelocytic leukemia bodies, but no intertelomeric copying or telomere exchange events were identified, and there was no increase in telomere dysfunction-induced foci. These data indicate that human cells possess a mechanism to negatively regulate telomere length by trimming telomeric DNA from the chromosome ends, most likely by t-loop resolution to form t-circles. Additionally, these results indicate that some phenotypic characteristics attributed to alternative lengthening of telomeres (ALT) result from increased mean telomere length, rather than from the ALT mechanism itself. PMID:19214183

  20. Kaposi’s sarcoma–associated herpesvirus stably clusters its genomes across generations to maintain itself extrachromosomally

    DOE PAGES

    Chiu, Ya-Fang; Sugden, Arthur U.; Fox, Kathryn; ...

    2017-07-10

    Genetic elements that replicate extrachromosomally are rare in mammals; however, several human tumor viruses, including the papillomaviruses and the gammaherpesviruses, maintain their plasmid genomes by tethering them to cellular chromosomes. We have uncovered an unprecedented mechanism of viral replication: Kaposi’s sarcoma–associated herpesvirus (KSHV) stably clusters its genomes across generations to maintain itself extrachromosomally. To identify and characterize this mechanism, we developed two complementary, independent approaches: live-cell imaging and a predictive computational model. The clustering of KSHV requires the viral protein, LANA1, to bind viral genomes to nucleosomes arrayed on both cellular and viral DNA. Clustering affects both viral partitioning andmore » viral genome numbers of KSHV. The clustering of KSHV plasmids provides it with an effective evolutionary strategy to rapidly increase copy numbers of genomes per cell at the expense of the total numbers of cells infected.« less

  1. Transaction Circles with Digital Texts as a Foundation for Democratic Practices

    ERIC Educational Resources Information Center

    Brown, Sally

    2015-01-01

    Transaction circles weave together elements of guided reading and literature circles in an open conversational structure that supports students as agentive learners. Discourse within these circles utilizing digital informational texts assist in the development of democratic practices even in a time when federal mandates limit curricula and…

  2. Learning about Aboriginal contexts: the reading circle approach.

    PubMed

    Begoray, Deborah L; Banister, Elizabeth

    2008-07-01

    As more opportunities arise for nursing students to obtain experience in community sites, they will be called on to practice in culturally appropriate ways more often. Although nurses remain challenged by the range of populations needing differentiated approaches, Aboriginal cultural contexts deserve special attention. Nurse educators must help students increase their understanding of Aboriginal life and ways of knowing. One way to facilitate this understanding is through a learning approach called reading circles. Reading circles offer a structure in the classroom for students to interact about ideas or readings. The reading circle process is congruent with Aboriginal ways of learning, which emphasize working in circle, with each member having a role and an equal chance to be heard. Aboriginal students in the class may be particularly comfortable with this learning method. This article describes specific steps for incorporating the reading circle approach into the nurse education classroom.

  3. [Polyadenylated RNA and mRNA export factors in extrachromosomal nuclear domains of vitellogenic oocytes of the insect Tenebrio molitor].

    PubMed

    Bogoliubov, D S; Kiselev, A M; Shabel'nikov, S V; Parfenov, V N

    2012-01-01

    The nucleus ofvitellogenic oocytes of the yellow mealworm, Tenebrio molitor, contains a karyosphere that consists of the condensed chromatin embedded in an extrachromosomal fibrogranular material. Numerous nuclear bodies located freely in the nucleoplasm are also observed. Amongst these bodies, counterparts of nuclear speckles (= interchromatin granule clusters, IGCs) can be identified by the presence of the marker protein SC35. Microinjections of fluorescently tagged methyloligoribonucleotide probes 2'-O-Me(U)22, complementary to poly(A) tails of RNAs, revealed poly(A)+ RNA in the vast majority of IGCs. We found that all T. molitor oocyte IGCs contain heterogeneous ribonucleoprotein (hnRNP) core protein Al that localizes to IGCs in an RNA-dependent manner. The extrachromosomal material of the karyosphere and a part of nucleoplasmic IGCs also contain the adapter protein Aly that is known to provide a link between pre-mRNA splicing and mRNA export. The essential mRNA export factor/receptor NXF1 was observed to colocalize with Aly. In nucleoplasmic IGCs, NXF1 was found to localize in an RNA-dependent manner whereas it is RNA-independently located in the extrachromosomal material of the karyosphere. We believe our data suggest on a role of the nucleoplasmic IGCs in mRNA biogenesis and retention in a road to nuclear export.

  4. Extrachromosomal HPV-16 LCR transcriptional activation by HDACi opposed by cellular differentiation and DNA integration

    PubMed Central

    Bojilova, Ekaterina Dimitrova; Weyn, Christine; Antoine, Marie-Hélène; Fontaine, Véronique

    2016-01-01

    Histone deacetylase inhibitors (HDACi) have been shown to render HPV-carrying cells susceptible to intrinsic and extrinsic apoptotic signals. As such, these epigenetic drugs have entered clinical trials in the effort to treat cervical cancer. Here, we studied the effect of common HDACi, with an emphasis on Trichostatin A (TSA), on the transcriptional activity of the HPV-16 Long Control Region (LCR) in order to better understand the impact of these agents in the context of the HPV life cycle and infection. HDACi strongly induced transcription of the firefly luciferase reporter gene under the control of the HPV-16 LCR in a variety of cell lines. In the HaCaT keratinocyte cell line undergoing differentiation induced by TSA, we observed a reduction in LCR-controlled transcription. Three major AP-1 binding sites in the HPV-16 LCR are involved in the regulation by TSA. However, whatever the status of differentiation of the HaCaT cells, TSA induced integration of extra-chromosomal transfected DNA into the cellular genome. Although these data suggest caution using HDACi in the treatment of HR HPV infection, further in vivo studies are necessary to better assess the risk. PMID:27705914

  5. Function of circle of Willis

    PubMed Central

    Vrselja, Zvonimir; Brkic, Hrvoje; Mrdenovic, Stefan; Radic, Radivoje; Curic, Goran

    2014-01-01

    Nearly 400 years ago, Thomas Willis described the arterial ring at the base of the brain (the circle of Willis, CW) and recognized it as a compensatory system in the case of arterial occlusion. This theory is still accepted. We present several arguments that via negativa should discard the compensatory theory. (1) Current theory is anthropocentric; it ignores other species and their analog structures. (2) Arterial pathologies are diseases of old age, appearing after gene propagation. (3) According to the current theory, evolution has foresight. (4) Its commonness among animals indicates that it is probably a convergent evolutionary structure. (5) It was observed that communicating arteries are too small for effective blood flow, and (6) missing or hypoplastic in the majority of the population. We infer that CW, under physiologic conditions, serves as a passive pressure dissipating system; without considerable blood flow, pressure is transferred from the high to low pressure end, the latter being another arterial component of CW. Pressure gradient exists because pulse wave and blood flow arrive into the skull through different cerebral arteries asynchronously, due to arterial tree asymmetry. Therefore, CW and its communicating arteries protect cerebral artery and blood–brain barrier from hemodynamic stress. PMID:24473483

  6. Function of circle of Willis.

    PubMed

    Vrselja, Zvonimir; Brkic, Hrvoje; Mrdenovic, Stefan; Radic, Radivoje; Curic, Goran

    2014-04-01

    Nearly 400 years ago, Thomas Willis described the arterial ring at the base of the brain (the circle of Willis, CW) and recognized it as a compensatory system in the case of arterial occlusion. This theory is still accepted. We present several arguments that via negativa should discard the compensatory theory. (1) Current theory is anthropocentric; it ignores other species and their analog structures. (2) Arterial pathologies are diseases of old age, appearing after gene propagation. (3) According to the current theory, evolution has foresight. (4) Its commonness among animals indicates that it is probably a convergent evolutionary structure. (5) It was observed that communicating arteries are too small for effective blood flow, and (6) missing or hypoplastic in the majority of the population. We infer that CW, under physiologic conditions, serves as a passive pressure dissipating system; without considerable blood flow, pressure is transferred from the high to low pressure end, the latter being another arterial component of CW. Pressure gradient exists because pulse wave and blood flow arrive into the skull through different cerebral arteries asynchronously, due to arterial tree asymmetry. Therefore, CW and its communicating arteries protect cerebral artery and blood-brain barrier from hemodynamic stress.

  7. Quality circles promote mine safety

    SciTech Connect

    Edwards, S.D.

    1983-04-01

    A ''quality circle'' is a small group of people (usually seven to 10 members), who meet on a regular basis to identify, analyze, and solve work-related problems. It is a means to develop employees rather than simply a technique to increase production or reduce waste. The ''people-oriented'' philosophy underlying quality circles is based on the idea that workers who are involved in decisions that affect their work become more productive. Quality circles are based on the concept of statistical analysis control first introduced in Japan by Dr. W. Edwards Deming. Today, there are more than 8,000,000 industrial workers in Japan participating in quality circles. This article outlines this concept as it evolved in quite a different setting, a surface coal mine in southwestern Illinois, United States.

  8. Introducing Motion in a Circle.

    ERIC Educational Resources Information Center

    Roche, John

    2001-01-01

    Motion in a circle troubled Newton and his contemporaries and troubles students today. Presents a clear presentation of certain aspects, particularly centripetal acceleration and centrifugal force. (Author/MM)

  9. Director Circles of Conic Sections

    ERIC Educational Resources Information Center

    Srinivasan, V. K.

    2002-01-01

    Given a conic section, the locus of a moving point in the plane of the conic section such that the two tangent lines drawn to the conic section from the moving point are all mutually perpendicular is a curve. In the case of an ellipse and hyperbola this curve is a circle referred to as the director circle. In the case of the parabola this curve…

  10. Director Circles of Conic Sections

    ERIC Educational Resources Information Center

    Srinivasan, V. K.

    2002-01-01

    Given a conic section, the locus of a moving point in the plane of the conic section such that the two tangent lines drawn to the conic section from the moving point are all mutually perpendicular is a curve. In the case of an ellipse and hyperbola this curve is a circle referred to as the director circle. In the case of the parabola this curve…

  11. Circle of Willis atherosclerosis, Alzheimer's disease and the Dean number.

    PubMed

    Ismailov, Rovshan M

    2013-10-26

    The important role of atherosclerosis in pathophysiology of Alzheimer's Disease has become evident. Mechanisms such as hyperlipidemia, inflammation, abdominal obesity and insulin resistance are important yet they may not fully explain the specific involvement of the Circle of Willis in these pathologies. The Circle of Wills is a complex geometrical structure which has several areas with different curvature as well as various branching angles of vessels composing the circle. The hemodynamics in this region should take into account the Dean number which indicates the influence of curvature on the resistance to blood flow. Thus, areas with various curvature and angles may have different hemodynamics and there are certain areas in the Circle of Willis that are more likely to develop atherosclerotic changes. Therefore, this could suggest the novel pathophysiological pathway resulting from the geometric peculiarities of the Circle of Willis. One of the directions of future research is to examine whether specific areas of the Circle of Willis are more likely to develop atherosclerotic changes compared to other ones. Selective areas of the Circle of Willis affected by atherosclerotic changes could indicate the primary role of atherosclerosis promoting Alzheimer's disease although other pathophysiological mechanisms suggesting the opposite direction should be also examined in prospective studies.

  12. Regulation and targeting of recombination in extrachromosomal substrates carrying immunoglobulin switch region sequences.

    PubMed Central

    Leung, H; Maizels, N

    1994-01-01

    We have used extrachromosomal substrates carrying immunoglobulin heavy-chain S mu and S gamma 3 switch region sequences to study activation and targeting of recombination by a transcriptional enhancer element. Substrates are transiently introduced into activated primary murine B cells, in which recombination involving S-region sequences deletes a conditionally lethal marker, and recombination is measured by transformation of Escherichia coli in the second step of the assay. Previously we found that as many as 25% of replicated substrates recombined during 40-h transfection of lipopolysaccharide (LPS)-stimulated primary cells and that efficient recombination was dependent on the presence of S-region sequences as well as a transcriptional activator region in the constructs (H. Leung and N. Maizels, Proc. Natl. Acad. Sci. USA 89:4154-4158, 1992). Here we show that recombination of the switch substrates is threefold more efficient in LPS-cultured primary B cells than in the T-cell line EL4; the activities responsible for switch substrate recombination thus appear to be more abundant or more active in cells which can carry out chromosomal switch recombination. We test the role of the transcriptional activator region and show that the immunoglobulin heavy-chain intron enhancer (E mu) alone stimulates recombination as well as E mu combined with a heavy-chain promoter and that mutations that diminish enhancer-dependent transcription 500-fold diminish recombinational activation less than 2-fold. These observations suggest that the enhancer stimulates recombination by a mechanism that does not depend on transcript production or that is insensitive to the level of transcript production over a very broad range. Furthermore, we find that E mu stimulates recombination when located either upstream or downstream of S mu but that the position of the recombinational activator does affect the targeting of recombination junctions, suggesting that the relatively imprecise targeting of

  13. The 'inner circle' of the cereal genomes.

    PubMed

    Bolot, Stéphanie; Abrouk, Michael; Masood-Quraishi, Umar; Stein, Nils; Messing, Joachim; Feuillet, Catherine; Salse, Jérôme

    2009-04-01

    Early marker-based macrocolinearity studies between the grass genomes led to arranging their chromosomes into concentric 'crop circles' of synteny blocks that initially consisted of 30 rice-independent linkage groups representing the ancestral cereal genome structure. Recently, increased marker density and genome sequencing of several cereal genomes allowed the characterization of intragenomic duplications and their integration with intergenomic colinearity data to identify paleo-duplications and propose a model for the evolution of the grass genomes from a common ancestor. On the basis of these data an 'inner circle' comprising five ancestral chromosomes was defined providing a new reference for the grass chromosomes and new insights into their ancestral relationships and origin, as well as an efficient tool to design cross-genome markers for genetic studies.

  14. Empirical Evaluation of Different Feature Representations for Social Circles Detection

    DTIC Science & Technology

    2015-06-16

    Kaggle competition on learning social circles in networks [5]. The data consist of hand- labelled friendship egonets from Facebook and a set of 57...study and compare the performance on the available labelled Facebook data from the Kaggle competition on learning social circles in networks. We...from both structural egonet information and user profile features. We study and compare the performance on the available labelled Facebook data from

  15. Circle nephrostomy tube revisited

    PubMed Central

    Noureldin, Yasser A.; Diab, Christian; Valenti, David; Andonian, Sero

    2016-01-01

    Introduction: There are few options for patients requiring chronic urinary drainage using nephrostomy tubes. Although circle nephrostomy tube (CNT) was invented in 1954, it is rarely used. Its advantages include longer indwelling time such that it is changed semi-annually when compared with the standard nephrostomy tube (SNT), which is changed monthly. However, there are no studies comparing indwelling times and costs with these two tubes. The aim of the present study was to compare CNT with SNT in terms of frequency of tube changes, reasons for earlier tube changes, and associated costs. Methods: Patients who had CNT inserted between 2009 and 2015 were reviewed. The indications for chronic indwelling nephrostomy tubes were tabulated. The frequency of tube changes was compared between CNT and SNT in the same patients. Furthermore, costs associated with insertion and exchange of CNT and SNT were analyzed. Results: Seven patients with mean age of 71.9 ± 7.6 years (range 43–96) had a total of 36 CNT changes. The mean number of CNT changes was four (range 2–5) at a mean interval of 168.3 ± 15.6 days (range 120–231). All patients had SNT prior to converting to CNT. When compared with the mean interval for SNT changes, the mean interval for CNT changes was significantly longer (44.8 ± 19.4 vs. 168.3 ± 41.3 days; p=0.028). Tube blockage and urinary leakage were the most common reasons for earlier than scheduled CNT changes. In our centre, CNT insertion and exchange cost $1965.48 and $923.96 compared with $1450.43 and $803.81 for SNT, respectively. There was an estimated cost savings of $46 861.10 (range $87 414.30 –$40 553.20) for the whole cohort by switching from SNTs to CNTs. Conclusions: Despite the small sample size as the main limitation, this study confirms that CNTs are associated with significantly fewer changes and lower cost when compared with SNTs for poor-surgical-risk patients requiring chronic NTs.

  16. Quality Circles: Determination of Significant Factors for Success an a General Model for Implementing a Quality Circle Process.

    DTIC Science & Technology

    1981-06-01

    12 Impact of Quality Circles . . . . . . . 15 The Quality Circle Process . . .. . . . . 17 Subjective Research ... . o . . 18 Summary...33 General Model for Implementing a Quality Circles Process........ .. ..... 90 . Quality Circles General Areas of System Impact ...historical background, the Quality Circle process, and the impact of Quality Circles upon an organization. Quality Circles Defined. "A Quality Circle

  17. Two Circles and Their Common Tangents

    ERIC Educational Resources Information Center

    Srinivasan, V. K.

    2002-01-01

    Given two circles C 1 and C 2 in a plane such that neither one of the two circles is contained in the other, there are either four common tangents when the circles do not intersect at all or the circles have three common tangents when they touch each other externally or only two common tangents when the circles intersect exactly at two points. The…

  18. Two Circles and Their Common Tangents

    ERIC Educational Resources Information Center

    Srinivasan, V. K.

    2002-01-01

    Given two circles C 1 and C 2 in a plane such that neither one of the two circles is contained in the other, there are either four common tangents when the circles do not intersect at all or the circles have three common tangents when they touch each other externally or only two common tangents when the circles intersect exactly at two points. The…

  19. Maintenance of very long telomeres by recombination in the Kluyveromyces lactis stn1-M1 mutant involves extreme telomeric turnover, telomeric circles, and concerted telomeric amplification.

    PubMed

    Xu, Jianing; McEachern, Michael J

    2012-08-01

    Some cancers utilize the recombination-dependent process of alternative lengthening of telomeres (ALT) to maintain long heterogeneous telomeres. Here, we studied the recombinational telomere elongation (RTE) of the Kluyveromyces lactis stn1-M1 mutant. We found that the total amount of the abundant telomeric DNA in stn1-M1 cells is subject to rapid variation and that it is likely to be primarily extrachromosomal. Rad50 and Rad51, known to be required for different RTE pathways in Saccharomyces cerevisiae, were not essential for the production of either long telomeres or telomeric circles in stn1-M1 cells. Circles of DNA containing telomeric repeats (t-circles) either present at the point of establishment of long telomeres or introduced later into stn1-M1 cells each led to the formation of long tandem arrays of the t-circle's sequence, which were incorporated at multiple telomeres. These tandem arrays were extraordinarily unstable and showed evidence of repeated rounds of concerted amplification. Our results suggest that the maintenance of telomeres in the stn1-M1 mutant involves extreme turnover of telomeric sequences from processes including both large deletions and the copying of t-circles.

  20. Charged particle dynamics in multiple colliding electromagnetic waves. Survey of random walk, Lévy flights, limit circles, attractors and structurally determinate patterns

    DOE PAGES

    Bulanov, S. V.; Esirkepov, T. Zh.; Koga, J. K.; ...

    2017-03-09

    The multiple colliding laser pulse concept formulated by Bulanovet al.(Phys. Rev. Lett., vol. 104, 2010b, 220404) is beneficial for achieving an extremely high amplitude of coherent electromagnetic field. Since the topology of electric and magnetic fields of multiple colliding laser pulses oscillating in time is far from trivial and the radiation friction effects are significant in the high field limit, the dynamics of charged particles interacting with the multiple colliding laser pulses demonstrates remarkable features corresponding to random walk trajectories, limit circles, attractors, regular patterns and Lévy flights. Lastly, under extremely high intensity conditions the nonlinear dissipation mechanism stabilizes the particle motionmore » resulting in the charged particle trajectory being located within narrow regions and in the occurrence of a new class of regular patterns made by the particle ensembles.« less

  1. The Anatomy of Circulus Arteriosus Cerebri (Circle of Willis): A Study in Turkish Population.

    PubMed

    Karatas, Ayse; Yilmaz, Hakan; Coban, Gokmen; Koker, Murat; Uz, Aysun

    2016-01-01

    The function of the circle of Willis, an arterial polygon, is to protect the brain from ischemia. The aim of this study is to define the structural characteristics of the circle of Willis within the Turkish adult population, along with variations and arteries involved in the measurement of diameters and lengths on cadavers. The circle of Willis was evaluated in 100 fresh adult cadavers. Structures of the circle of Willis were evaluated as being typical or atypical images and according to the diameter of AComP. All arteries forming the circle's length and diameters were measured. All arteries forming the circle of Willis as 91% were anatomically observed. The typical structure in which hypoplasia arteries is not involved was obtained as 8%. The atypical circle of Willis with aplasia was seen as 9%. 87% of adult, 9% fetal, and 4% transitional configuration in the samples were detected. The variations of the circle of Willis were more common in the posterior portion. Hypoplasia was found to be the most common variation and noted as a maximum in AComP (85%). Aplasia was noted as the second most common variation after hypoplasia and again the most common in AComP (5%). Advances in radiological methods which provide images of cerebral vessels and the development of cerebrovascular surgery have increased the importance of the circle of Willis in neurosurgery and neurology. The structure of the circle of Willis is of great importance in occlusive cerebrovascular diseases and cerebrovascular surgery.

  2. Gene amplification system based on double rolling-circle replication as a model for oncogene-type amplification.

    PubMed

    Watanabe, Takaaki; Tanabe, Hideyuki; Horiuchi, Takashi

    2011-09-01

    Gene amplification contributes to a variety of biological phenomena, including malignant progression and drug resistance. However, details of the molecular mechanisms remain to be determined. Here, we have developed a gene amplification system in yeast and mammalian cells that is based on double rolling-circle replication (DRCR). Cre-lox system is used to efficiently induce DRCR utilizing a recombinational process coupled with replication. This system shows distinctive features seen in amplification of oncogenes and drug-resistance genes: (i) intra- and extrachromosomal amplification, (ii) intensive chromosome rearrangement and (iii) scattered-type amplification resembling those seen in cancer cells. This system can serve as a model for amplification of oncogenes and drug-resistance genes, and improve amplification systems used for making pharmaceutical proteins in mammalian cells.

  3. The Circle Approach to Trigonometry

    ERIC Educational Resources Information Center

    Moore, Kevin c.; LaForest, Kevin R.

    2014-01-01

    How do students think about an angle measure of ninety degrees? How do they think about ratios and values on the unit circle? How might angle measure be used to connect right-triangle trigonometry and circular functions? And why might asking these questions be important when introducing trigonometric functions to students? When teaching…

  4. On a Family of Circles

    ERIC Educational Resources Information Center

    Feeman, Timothy G.

    2011-01-01

    We generalize a standard example from precalculus and calculus texts to give a simple description in polar coordinates of any circle that passes through the origin. We discuss an occurrence of this formula in the context of medical imaging. (Contains 1 figure.)

  5. Quality Circles that Enhance Productivity.

    ERIC Educational Resources Information Center

    Romine, Larry

    1981-01-01

    Profiles Lane Community College's use of the quality circle concept to raise quality while holding down costs, whereby a voluntary group of 12 employees working in the same department meet one hour per week to identify, analyze, and solve work-related problems and implement solutions proposed to and approved by management. (DMM)

  6. Digital Storytelling: Reinventing Literature Circles

    ERIC Educational Resources Information Center

    Tobin, Maryann Tatum

    2012-01-01

    New literacies in reading research demand the study of comprehension skills using multiple modalities through a more complex, multi-platform view of reading. Taking into account the robust roll of technology in our daily lives, this article presents an update to the traditional literature circle lesson to include digital storytelling and…

  7. Quality Circles that Enhance Productivity.

    ERIC Educational Resources Information Center

    Romine, Larry

    1981-01-01

    Profiles Lane Community College's use of the quality circle concept to raise quality while holding down costs, whereby a voluntary group of 12 employees working in the same department meet one hour per week to identify, analyze, and solve work-related problems and implement solutions proposed to and approved by management. (DMM)

  8. On the Circle of Apollonius

    ERIC Educational Resources Information Center

    Ayoub, Ayoub B.

    2006-01-01

    The circle discussed in this paper is named after "The Great Geometer of Antiquity", that is Apollonius of Perga (ca. 262-190 BCE). Among his many contributions to geometry is a book with the title "Plane Loci." This book included, among others, a problem about the locus of a point moving in a plane such that the ratio of its distances from two…

  9. The Circle Approach to Trigonometry

    ERIC Educational Resources Information Center

    Moore, Kevin c.; LaForest, Kevin R.

    2014-01-01

    How do students think about an angle measure of ninety degrees? How do they think about ratios and values on the unit circle? How might angle measure be used to connect right-triangle trigonometry and circular functions? And why might asking these questions be important when introducing trigonometric functions to students? When teaching…

  10. Are Quality Circles Right for Your Company?

    ERIC Educational Resources Information Center

    Ambler, Aldonna R.; Overholt, Miles H.

    1982-01-01

    The concept of quality circles is discussed. The authors explore company compatibility with Japanese management philosophy, a compatibility test, planning for the change to quality circles, need for a flexible design, and setting worthwhile goals. (CT)

  11. Quality circles: Organizational adaptations, improvements and results

    NASA Technical Reports Server (NTRS)

    Tortorich, R.

    1985-01-01

    The effective application in industry and government of quality circles work was demonstrated. The results achieved in quality and productivity improvements and cost savings are impressive. The circle process should be institutionalized within industry and government. The stages of circle program growth, innovations that help achieve circle process institutionalization, and the result achieved at Martin Marietta's Michoud Division and within the National Aeronautics and Space Administration (NASA) are addressed.

  12. Yarning Circles in the Literacy Classroom

    ERIC Educational Resources Information Center

    Mills, Kathy A.; Sunderland, Naomi; Davis-Warra, John

    2014-01-01

    This article explains how the speaking and listening practice of yarning circles can be used in the literacy classroom. The article opens with an account of a live enactment of yarning circles with elementary students in a mainstream classroom in Australia. It explains the purpose and origin of yarning circles in Indigenous communities, and…

  13. Science Literacy Circles: Big Ideas about Science

    ERIC Educational Resources Information Center

    Devick-Fry, Jane; LeSage, Teresa

    2010-01-01

    Science literacy circles incorporate the organization of both science notebooks and literature circles to help K-8 students internalize big ideas about science. Using science literacy circles gives students opportunities to engage in critical thinking as they inductively develop understanding about science concepts. (Contains 1 table and 7…

  14. Yarning Circles in the Literacy Classroom

    ERIC Educational Resources Information Center

    Mills, Kathy A.; Sunderland, Naomi; Davis-Warra, John

    2014-01-01

    This article explains how the speaking and listening practice of yarning circles can be used in the literacy classroom. The article opens with an account of a live enactment of yarning circles with elementary students in a mainstream classroom in Australia. It explains the purpose and origin of yarning circles in Indigenous communities, and…

  15. Perceptual Differences in Attitudes on Quality Circles.

    ERIC Educational Resources Information Center

    Holcomb, Lynn; Berger, Leonard

    1986-01-01

    A study was conducted to determine any perceptual differences toward quality circles in a chemical plant. It also tried to determine if any perceptual differences that might be found could be related to attitudes toward the circles themselves or the attitudes toward circle members. Length of service was also a factor. (CT)

  16. Creating Circle of Courage Schools

    ERIC Educational Resources Information Center

    Van Bockern, Steve; McDonald, Tim

    2012-01-01

    Dream what a school would be like in which the purpose is to meet the needs of children and the larger community so that all can lead a good life. Using the Circle of Courage[TM]--a model grounded in values of deep respect for the dignity of all--the authors of this article outline overarching goals and indicators that can turn this dream into…

  17. Creating Circle of Courage Schools

    ERIC Educational Resources Information Center

    Van Bockern, Steve; McDonald, Tim

    2012-01-01

    Dream what a school would be like in which the purpose is to meet the needs of children and the larger community so that all can lead a good life. Using the Circle of Courage[TM]--a model grounded in values of deep respect for the dignity of all--the authors of this article outline overarching goals and indicators that can turn this dream into…

  18. Nanogrid rolling circle DNA sequencing

    DOEpatents

    Church, George M.; Porreca, Gregory J.; Shendure, Jay; Rosenbaum, Abraham Meir

    2017-04-18

    The present invention relates to methods for sequencing a polynucleotide immobilized on an array having a plurality of specific regions each having a defined diameter size, including synthesizing a concatemer of a polynucleotide by rolling circle amplification, wherein the concatemer has a cross-sectional diameter greater than the diameter of a specific region, immobilizing the concatemer to the specific region to make an immobilized concatemer, and sequencing the immobilized concatemer.

  19. Yeast plasmid 2-micron circle promotes recombination within bacterial transposon Tn5.

    PubMed Central

    Jayaram, M; Broach, J R

    1983-01-01

    The site-specific recombination system (FLP) encoded by the yeast plasmid 2-micron circle can also act in yeast on the inverted repeats of the bacterial transposon Tn5. The efficiency of this recombination is dependent on the location of Tn5 within the 2-micron circle genome but can be as high as that observed for 2-micron circle itself. Comparison of the DNA sequences between the Tn5 repeat and the 2-micron circle recombination region reveals certain strikingly similar structural features that might be important in the recombination reaction. Images PMID:6316350

  20. Structures of replication initiation proteins from staphylococcal antibiotic resistance plasmids reveal protein asymmetry and flexibility are necessary for replication

    PubMed Central

    Carr, Stephen B.; Phillips, Simon E.V.; Thomas, Christopher D.

    2016-01-01

    Antibiotic resistance in pathogenic bacteria is a continual threat to human health, often residing in extrachromosomal plasmid DNA. Plasmids of the pT181 family are widespread and confer various antibiotic resistances to Staphylococcus aureus. They replicate via a rolling circle mechanism that requires a multi-functional, plasmid-encoded replication protein to initiate replication, recruit a helicase to the site of initiation and terminate replication after DNA synthesis is complete. We present the first atomic resolution structures of three such replication proteins that reveal distinct, functionally relevant conformations. The proteins possess a unique active site and have been shown to contain a catalytically essential metal ion that is bound in a manner distinct from that of any other rolling circle replication proteins. These structures are the first examples of the Rep_trans Pfam family providing insights into the replication of numerous antibiotic resistance plasmids from Gram-positive bacteria, Gram-negative phage and the mobilisation of DNA by conjugative transposons. PMID:26792891

  1. Structures of replication initiation proteins from staphylococcal antibiotic resistance plasmids reveal protein asymmetry and flexibility are necessary for replication.

    PubMed

    Carr, Stephen B; Phillips, Simon E V; Thomas, Christopher D

    2016-03-18

    Antibiotic resistance in pathogenic bacteria is a continual threat to human health, often residing in extrachromosomal plasmid DNA. Plasmids of the pT181 family are widespread and confer various antibiotic resistances to Staphylococcus aureus. They replicate via a rolling circle mechanism that requires a multi-functional, plasmid-encoded replication protein to initiate replication, recruit a helicase to the site of initiation and terminate replication after DNA synthesis is complete. We present the first atomic resolution structures of three such replication proteins that reveal distinct, functionally relevant conformations. The proteins possess a unique active site and have been shown to contain a catalytically essential metal ion that is bound in a manner distinct from that of any other rolling circle replication proteins. These structures are the first examples of the Rep_trans Pfam family providing insights into the replication of numerous antibiotic resistance plasmids from Gram-positive bacteria, Gram-negative phage and the mobilisation of DNA by conjugative transposons. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  2. Camera calibration using two concentric circles: linear approach

    NASA Astrophysics Data System (ADS)

    Ma, Wenjuan; Zheng, Yinqiang; Liu, Yuncai

    2009-05-01

    We present a new algorithm for camera calibration using two concentric circles, which is a linear approach. In the calibration, a pinhole camera model is used. Different from previous methods, we take the projective equations of 3-D circles, which include the intrinsic parameter matrix of the camera, as the basis of our calibration approach. According to the special structure of the projective equations in algebra, we can get a linear equation system about the intrinsic parameters. After enough equations are constructed, the calibration can be easily finished. With at least three images of the two concentric circles, all five intrinsic parameters can be recovered. Experiments using computer simulated data and real data demonstrate the robustness and accuracy of our method.

  3. Textmasters: Bringing Literature Circles to Textbook Reading across the Curriculum

    ERIC Educational Resources Information Center

    Wilfong, Lori G.

    2009-01-01

    A fifth-grade science teacher and university researcher challenged the notion that textbook reading follows the same archaic formula: read the textbook and answer the questions at the end of the section. Together, they adapted literature circle roles to fit textbook structures, resulting in the strategy they call Textmasters. This article…

  4. Assessment of the Circle of Willis with Cranial Tomography Angiography.

    PubMed

    Karatas, Ayse; Coban, Gokmen; Cinar, Celal; Oran, Ismail; Uz, Aysun

    2015-09-06

    The circle of Willis is a major collateral pathway important in ischemic conditions. The aim of our study was to assess the structural characteristics of the circle of Willis within the Turkish adult population, along with variations and arteries involved in the measurement of diameters and lengths on cranial computed tomography angiography (CTA). One hundred adult patients who underwent CTA images were evaluated retrospectively. Results of the study revealed 82% adult, 17% fetal, and 1% transitional configurations. A complete polygonal structure was observed in 28% of cases. Variations of the circle of Willis were more common in the posterior portion. Hypoplasia was found to be the most common variation and was observed as a maximum in the posterior communicating artery (AComP). The patency and size of arteries in the circle of Willis are important in occlusive cerebrovascular diseases and cerebrovascular surgery. Although CTA is an easily accessible non-invasive clinical method for demonstrating the vascular structure, CTA should be evaluated taking into account image resolution quality and difficulties in the identification of small vessels.

  5. Evidence against equimolarity of large repeat arrangements and a predominant master circle structure of the mitochondrial genome from a monkeyflower (Mimulus guttatus) lineage with cryptic CMS.

    PubMed

    Mower, Jeffrey P; Case, Andrea L; Floro, Eric R; Willis, John H

    2012-01-01

    Despite intense investigation for over 25 years, the in vivo structure of plant mitochondrial genomes remains uncertain. Mapping studies and genome sequencing generally produce large circular chromosomes, whereas electrophoretic and microscopic studies typically reveal linear and multibranched molecules. To more fully assess the structure of plant mitochondrial genomes, the complete sequence of the monkeyflower (Mimulus guttatus DC. line IM62) mitochondrial DNA was constructed from a large (35 kb) paired-end shotgun sequencing library to a high depth of coverage (~30×). The complete genome maps as a 525,671 bp circular molecule and exhibits a fairly conventional set of features including 62 genes (encoding 35 proteins, 24 transfer RNAs, and 3 ribosomal RNAs), 22 introns, 3 large repeats (2.7, 9.6, and 29 kb), and 96 small repeats (40-293 bp). Most paired-end reads (71%) mapped to the consensus sequence at the expected distance and orientation across the entire genome, validating the accuracy of assembly. Another 10% of reads provided clear evidence of alternative genomic conformations due to apparent rearrangements across large repeats. Quantitative assessment of these repeat-spanning read pairs revealed that all large repeat arrangements are present at appreciable frequencies in vivo, although not always in equimolar amounts. The observed stoichiometric differences for some arrangements are inconsistent with a predominant master circular structure for the mitochondrial genome of M. guttatus IM62. Finally, because IM62 contains a cryptic cytoplasmic male sterility (CMS) system, an in silico search for potential CMS genes was undertaken. The three chimeric open reading frames (ORFs) identified in this study, in addition to the previously identified ORFs upstream of the nad6 gene, are the most likely CMS candidate genes in this line.

  6. Evidence against Equimolarity of Large Repeat Arrangements and a Predominant Master Circle Structure of the Mitochondrial Genome from a Monkeyflower (Mimulus guttatus) Lineage with Cryptic CMS

    PubMed Central

    Mower, Jeffrey P.; Case, Andrea L.; Floro, Eric R.; Willis, John H.

    2012-01-01

    Despite intense investigation for over 25 years, the in vivo structure of plant mitochondrial genomes remains uncertain. Mapping studies and genome sequencing generally produce large circular chromosomes, whereas electrophoretic and microscopic studies typically reveal linear and multibranched molecules. To more fully assess the structure of plant mitochondrial genomes, the complete sequence of the monkeyflower (Mimulus guttatus DC. line IM62) mitochondrial DNA was constructed from a large (35 kb) paired-end shotgun sequencing library to a high depth of coverage (∼30×). The complete genome maps as a 525,671 bp circular molecule and exhibits a fairly conventional set of features including 62 genes (encoding 35 proteins, 24 transfer RNAs, and 3 ribosomal RNAs), 22 introns, 3 large repeats (2.7, 9.6, and 29 kb), and 96 small repeats (40–293 bp). Most paired-end reads (71%) mapped to the consensus sequence at the expected distance and orientation across the entire genome, validating the accuracy of assembly. Another 10% of reads provided clear evidence of alternative genomic conformations due to apparent rearrangements across large repeats. Quantitative assessment of these repeat-spanning read pairs revealed that all large repeat arrangements are present at appreciable frequencies in vivo, although not always in equimolar amounts. The observed stoichiometric differences for some arrangements are inconsistent with a predominant master circular structure for the mitochondrial genome of M. guttatus IM62. Finally, because IM62 contains a cryptic cytoplasmic male sterility (CMS) system, an in silico search for potential CMS genes was undertaken. The three chimeric open reading frames (ORFs) identified in this study, in addition to the previously identified ORFs upstream of the nad6 gene, are the most likely CMS candidate genes in this line. PMID:22534162

  7. Mosaic Analysis Using a Ncl-1 (+) Extrachromosomal Array Reveals That Lin-31 Acts in the Pn.p Cells during Caenorhabditis Elegans Vulval Development

    PubMed Central

    Miller, L. M.; Waring, D. A.; Kim, S. K.

    1996-01-01

    We describe a genetic mosaic analysis procedure in which Caenorhabditis elegans mosaics are generated by spontaneous loss of an extrachromosomal array. This technique allows almost any C. elegans gene that can be used in germline transformation experiments to be used in mosaic analysis experiments. We identified a cosmid clone that rescues the mutant phenotype of ncl-1, so that this cell-autonomous marker could be used to analyze mosaic animals. To determine the sites of action for unc-29 and lin-31, an extrachromosomal array was constructed containing the ncl-1(+) cosmid linked to lin-31(+) and unc-29(+) cosmids. This array is mitotically unstable and can be lost to produce a clone of mutant cells. The specific cell division at which the extrachromosomal array had been lost was deduced by scoring the Ncl phenotypes of individual cells in genetic mosaics. The Unc-29 and Lin-31 phenotypes were then scored in these animals to determine in which cells these genes are required. This analysis showed that unc-29, which encodes a subunit of the acetylcholine receptor, acts in the body muscle cells. Furthermore, lin-31, which specifies cell fates during vulval induction and encodes a putative transcription factor similar to HNF-3/fork head, acts in the Pn.p cells. PMID:8807292

  8. "Online Literature Circles Rock!" Organizing Online Literature Circles in a Middle School Classroom

    ERIC Educational Resources Information Center

    Day, Deanna; Kroon, Sally

    2010-01-01

    Fifty-one sixth graders participated in three rounds of online literature circles and three face-to-face literature circles. The authors describe how the online literature circles were introduced and organized in the classroom and discuss the tensions, struggles, and successes from their implementation. An analysis of qualitative data yielded…

  9. The Study Circle Handbook. A Manual for Study Circle Discussion Leaders, Organizers, and Participants.

    ERIC Educational Resources Information Center

    Topsfield Foundation, Pomfret, CT. Study Circles Resource Center.

    This handbook presents the fundamentals of successful study circle leadership. It also includes pointers for study circle organizers and participants, concluding with a comparison of dialogue and debate--a guide for distinguishing study circles from other types of discussion. The guide contains seven sections that cover the following topics: (1)…

  10. Small RNA-based feedforward loop with AND-gate logic regulates extrachromosomal DNA transfer in Salmonella.

    PubMed

    Papenfort, Kai; Espinosa, Elena; Casadesús, Josep; Vogel, Jörg

    2015-08-25

    Horizontal gene transfer via plasmid conjugation is a major driving force in microbial evolution but constitutes a complex process that requires synchronization with the physiological state of the host bacteria. Although several host transcription factors are known to regulate plasmid-borne transfer genes, RNA-based regulatory circuits for host-plasmid communication remain unknown. We describe a posttranscriptional mechanism whereby the Hfq-dependent small RNA, RprA, inhibits transfer of pSLT, the virulence plasmid of Salmonella enterica. RprA employs two separate seed-pairing domains to activate the mRNAs of both the sigma-factor σ(S) and the RicI protein, a previously uncharacterized membrane protein here shown to inhibit conjugation. Transcription of ricI requires σ(S) and, together, RprA and σ(S) orchestrate a coherent feedforward loop with AND-gate logic to tightly control the activation of RicI synthesis. RicI interacts with the conjugation apparatus protein TraV and limits plasmid transfer under membrane-damaging conditions. To our knowledge, this study reports the first small RNA-controlled feedforward loop relying on posttranscriptional activation of two independent targets and an unexpected role of the conserved RprA small RNA in controlling extrachromosomal DNA transfer.

  11. Small RNA-based feedforward loop with AND-gate logic regulates extrachromosomal DNA transfer in Salmonella

    PubMed Central

    Papenfort, Kai; Espinosa, Elena; Casadesús, Josep; Vogel, Jörg

    2015-01-01

    Horizontal gene transfer via plasmid conjugation is a major driving force in microbial evolution but constitutes a complex process that requires synchronization with the physiological state of the host bacteria. Although several host transcription factors are known to regulate plasmid-borne transfer genes, RNA-based regulatory circuits for host–plasmid communication remain unknown. We describe a posttranscriptional mechanism whereby the Hfq-dependent small RNA, RprA, inhibits transfer of pSLT, the virulence plasmid of Salmonella enterica. RprA employs two separate seed-pairing domains to activate the mRNAs of both the sigma-factor σS and the RicI protein, a previously uncharacterized membrane protein here shown to inhibit conjugation. Transcription of ricI requires σS and, together, RprA and σS orchestrate a coherent feedforward loop with AND-gate logic to tightly control the activation of RicI synthesis. RicI interacts with the conjugation apparatus protein TraV and limits plasmid transfer under membrane-damaging conditions. To our knowledge, this study reports the first small RNA-controlled feedforward loop relying on posttranscriptional activation of two independent targets and an unexpected role of the conserved RprA small RNA in controlling extrachromosomal DNA transfer. PMID:26307765

  12. Campoletis sonorensis Endoparasitic Wasps Contain Forms of C. sonorensis Virus DNA Suggestive of Integrated and Extrachromosomal Polydnavirus DNAs

    PubMed Central

    Fleming, Jo-Ann G. W.; Summers, Max D.

    1986-01-01

    Campoletis sonorensis virus (CsV) (Polydnaviridae) previously was detected only in the calyx epithelial cells and lumen of the oviducts from female C. sonorensis (Ichneumonidae) endoparasitic wasps (Norton et al., Cell Tissue Res. 162:195-208, 1975). Using dot-blot hybridizations, we detected low amounts of CsV DNA in male and female wasp head and thorax tissues and in male abdominal tissues. Low amounts of extrachromosomal viral DNA were detected in Southern blots of undigested male wasp DNA and in male DNA purified by isopycnic centrifugation. High-molecular-weight male wasp DNA digested with any of several restriction endonucleases and hybridized with cloned viral DNAs from CsV superhelices B and Q under stringent conditions contained CsV-specific DNA fragments that differed significantly in size and number from the hybridizing fragments detected in comparably digested viral DNA. Identical offsize restriction fragments were detected in digested female head and thorax DNA. These data suggest that at least CsV DNAs B and Q are integrated in C. sonorensis cellular DNA and that the virus may be transmitted through the germline. Images PMID:16789255

  13. Extrachromosomal homologous DNA recombination in plant cells is fast and is not affected by CpG methylation.

    PubMed Central

    Puchta, H; Kocher, S; Hohn, B

    1992-01-01

    Using a sensitive transient assay, we investigated extrachromosomal homologous DNA recombination (ECR) in plant cells. As the plant genome is highly C methylated, we addressed the question of whether CpG methylation has an influence on DNA recombination efficiencies. Whereas the expression level of the fully CpG-methylated DNA molecules was reduced drastically, we found no significant changes in ECR efficiencies between two partly CpG-methylated plasmids or between one fully CpG-methylated and one nonmethylated plasmid. Using a modified polymerase chain reaction analysis, we were able to detect recombination between two fully CpG-methylated plasmids. Furthermore, we characterized the kinetics of the ECR reaction. Cotransfection of plasmids carrying truncated copies of the beta-glucuronidase (GUS) gene resulted in enzyme activity with a delay of only half an hour compared with that of the plasmid carrying the functional marker gene. This indicates that the ECR reaction itself requires no more than 30 min. By polymerase chain reaction, we were able to detect the recombined GUS gene as early as 2 h after transfection. This result and the time course of the transient GUS activity indicate that ECR occurs mainly early after transfection. The biological significance of this finding is discussed, and properties of ECR and intrachromosomal recombination are compared. Images PMID:1630452

  14. Unit Circles and Inverse Trigonometric Functions

    ERIC Educational Resources Information Center

    Barrera, Azael

    2014-01-01

    Historical accounts of trigonometry refer to the works of many Indian and Arab astronomers on the origin of the trigonometric functions as we know them now, in particular Abu al-Wafa (ca. 980 CE), who determined and named all known trigonometric functions from segments constructed on a regular circle and later on a unit circle (Moussa 2011;…

  15. Creating Learning Communities through Circles of Learning.

    ERIC Educational Resources Information Center

    Funk, Carole

    One of the critical elements of effective schools developed as a result of recent reform efforts and restructuring processes was the concept of learning communities and learning circles. This short paper discusses learning communities and learning circles. It defines learning communities as "a fellowship of learners in which the teachers in a…

  16. Unit Circles and Inverse Trigonometric Functions

    ERIC Educational Resources Information Center

    Barrera, Azael

    2014-01-01

    Historical accounts of trigonometry refer to the works of many Indian and Arab astronomers on the origin of the trigonometric functions as we know them now, in particular Abu al-Wafa (ca. 980 CE), who determined and named all known trigonometric functions from segments constructed on a regular circle and later on a unit circle (Moussa 2011;…

  17. Euclidean Circles and Their Modular Images.

    ERIC Educational Resources Information Center

    Austin, Joe Dan

    1990-01-01

    Shows a series of Euclidean equations using the Euclidean algorithm to get the greatest common divisor of two integers. Describes the use of the equations to generate a series of circles. Discusses computer generation of Euclidean circles and provides a BASIC program. (YP)

  18. Building Background Knowledge within Literature Circles

    ERIC Educational Resources Information Center

    Barone, Diane; Barone, Rebecca

    2012-01-01

    The authors examined the strength of literature circles in developing background knowledge--an acknowledged sticking point in the development of understanding for middle graders--with a special focus on the literature circle role of "investigator," where it is student initiative and not teacher direction that guides comprehension. Observing…

  19. The Reading Circle Movement in Texas

    ERIC Educational Resources Information Center

    Spearman, Mindy

    2007-01-01

    In the late-nineteenth and early-twentieth centuries, state-sponsored reading circles provided American teachers with an opportunity for low-cost professional development. Teachers who participated in reading circles read professional literature, discussed the material with colleagues, and, occasionally, completed written assignments based on the…

  20. Universal estimates for critical circle mappings.

    PubMed

    Khanin, K. M.

    1991-08-01

    A thermodynamic formalism is constructed for critical circle mappings. It is used to prove universal estimates for the asymptotic behavior of renormalized mappings. Certain applications of statistical mechanics to research on the ergodic properties of critical homeomorphisms of a circle are also discussed.

  1. Thomas Willis of the "circle of Willis".

    PubMed

    Choudhari, Kishor A; Sharma, Divyesh; Leyon, Joe J

    2008-12-01

    Thomas Willis is best known for the circle of Willis. The life story of this 17th- century medical genius, who remains an inspiration for all neuroscientists 300 years later, is summarized in this article. We outline his academic achievements, including his description of the famous basal arterial circle, and we attempt to obtain insight into his visionary thought process through this historical review.

  2. Building Background Knowledge within Literature Circles

    ERIC Educational Resources Information Center

    Barone, Diane; Barone, Rebecca

    2012-01-01

    The authors examined the strength of literature circles in developing background knowledge--an acknowledged sticking point in the development of understanding for middle graders--with a special focus on the literature circle role of "investigator," where it is student initiative and not teacher direction that guides comprehension. Observing…

  3. Developing Soft Skills Using "Literature Circles"

    ERIC Educational Resources Information Center

    Azmi, Mohd Nazri Bin Latiff

    2013-01-01

    This study investigates the impact of the implementation of "Literature Circles" in an Active Learning classroom in relations to developing soft skills among university students. The use of Literature Circles is a well-known strategy in teaching the students to be more creative, independent, and think out of the box. A group of…

  4. Biomechanical analysis of circles on pommel horse.

    PubMed

    Fujihara, Toshiyuki; Fuchimoto, Takafumi; Gervais, Pierre

    2009-03-01

    The aim of this study was to analyse the principal mechanics of circles. Seventeen university male gymnasts performed circles on an instrumented pommel horse model that enabled the pommel reaction forces to be recorded at 1000 Hz with two force plates. The circles were also videotaped using two digital video cameras operating at 60 frames per second. During circles, the vertical component of the reaction forces peaked in the double-hand support phases. Changes in the velocity of the centre of mass corresponded to the change in the tangential components of horizontal reaction forces. The velocity of the centre of mass had its peaks in the single-hand support phases and its local minimums in the double-hand support phases. The velocity of the ankles and that of the centre of mass of the head and trunk were minimal in the single-hand support phases and were maximal in the double-hand support phases. These results suggest that the circles were composed of vertical movements and two kinds of rotations: rotation of the centre of mass and rotation of the body itself about the centre of mass. These two kinds of rotations, which influence the legs' rotational velocity, are phase dependent. To further our understanding of circles, research on circles in different orientations on the pommel horse will be beneficial.

  5. Plasmid Rolling-Circle Replication.

    PubMed

    Ruiz-Masó, J A; MachóN, C; Bordanaba-Ruiseco, L; Espinosa, M; Coll, M; Del Solar, G

    2015-02-01

    Plasmids are DNA entities that undergo controlled replication independent of the chromosomal DNA, a crucial step that guarantees the prevalence of the plasmid in its host. DNA replication has to cope with the incapacity of the DNA polymerases to start de novo DNA synthesis, and different replication mechanisms offer diverse solutions to this problem. Rolling-circle replication (RCR) is a mechanism adopted by certain plasmids, among other genetic elements, that represents one of the simplest initiation strategies, that is, the nicking by a replication initiator protein on one parental strand to generate the primer for leading-strand initiation and a single priming site for lagging-strand synthesis. All RCR plasmid genomes consist of a number of basic elements: leading strand initiation and control, lagging strand origin, phenotypic determinants, and mobilization, generally in that order of frequency. RCR has been mainly characterized in Gram-positive bacterial plasmids, although it has also been described in Gram-negative bacterial or archaeal plasmids. Here we aim to provide an overview of the RCR plasmids' lifestyle, with emphasis on their characteristic traits, promiscuity, stability, utility as vectors, etc. While RCR is one of the best-characterized plasmid replication mechanisms, there are still many questions left unanswered, which will be pointed out along the way in this review.

  6. Examination of the Circle Spline Routine

    NASA Technical Reports Server (NTRS)

    Dolin, R. M.; Jaeger, D. L.

    1985-01-01

    The Circle Spline routine is currently being used for generating both two and three dimensional spline curves. It was developed for use in ESCHER, a mesh generating routine written to provide a computationally simple and efficient method for building meshes along curved surfaces. Circle Spline is a parametric linear blending spline. Because many computerized machining operations involve circular shapes, the Circle Spline is well suited for both the design and manufacturing processes and shows promise as an alternative to the spline methods currently supported by the Initial Graphics Specification (IGES).

  7. Characterization of the extrachromosomal function (ECF) sigma factors of Arcobacter butzleri

    USDA-ARS?s Scientific Manuscript database

    Campylobacter jejuni is the most commonly reported cause of bacterial foodborne illness in North America. C. jejuni decorates its surface polysaccharides with a variety of variable phosphorylated structures, including O-methyl phosphoramidate (MeOPN) modifications on the capsular polysaccharide. Alt...

  8. Analysis of the VPE sequences in the Caenorhabditis elegans vit-2 promoter with extrachromosomal tandem array-containing transgenic strains.

    PubMed Central

    MacMorris, M; Spieth, J; Madej, C; Lea, K; Blumenthal, T

    1994-01-01

    The Caenorhabditis elegans vit genes, encoding vitellogenins, are abundantly expressed in the adult hermaphrodite intestine. Two repeated elements, vit promoter element 1 (VPE1 [TGTCAAT]) and VPE2 (CTGATAA), have been identified in the 5' flanking DNA of each of the vit genes of C. elegans and Caenorhabditis briggsae. These elements have previously been shown to be needed for correctly regulated expression of a vit-2/vit-6 fusion gene in low-copy-number, integrated transgenes. Here we extend the analysis of the function of VPE1 and VPE2 by using transgenic lines carrying large, extrachromosomal arrays of the test genes. The results validate the use of such arrays for transgenic analysis of gene regulation in C. elegans, by confirming previous findings showing that the VPE1 at -45 and both VPE2s are sites of activation. Additional experiments now indicate that when the -45 VPE1 is inverted or replaced by a VPE2, nearly total loss of promoter function results, suggesting that the highly conserved -45 VPE1 plays a unique role in vit-2 promoter function. In contrast, single mutations eliminating the three upstream VPE1s are without effect. However, in combination in double and triple mutants, these upstream VPE1 mutations cause drastic reductions in expression levels. The -150 VPE2 can be replaced by a XhoI site (CTCGAG), and the -90 VPE2 can be eliminated, as long as the overlapping VPE1 is left intact, but when these two replacements are combined, activity is lost. Thus, the promoter must have at least one VPE2 and it must have at least two VPE1s, one at -45 and one additional upstream element. Images PMID:8264616

  9. Extrachromosomal sequences of hepatitis B virus DNA in peripheral blood mononuclear cells of acquired immune deficiency syndrome patients.

    PubMed

    Noonan, C A; Yoffe, B; Mansell, P W; Melnick, J L; Hollinger, F B

    1986-08-01

    The primary etiologic agent of the acquired immune deficiency syndrome (AIDS) is a human T-lymphotropic retrovirus (the AIDS virus). However, the pathogenesis of this virus suggests that other cofactors may contribute to the development of clinically overt disease. The hepatitis B virus (HBV) has been implicated as a potential cofactor because HBV and AIDS virus infections frequently coexist, striking similarities exist in their epidemiologic patterns, and recent data indicate that HBV is lymphotropic. To establish the prevalence of HBV infections in lymphoid cells from individuals with AIDS-related disorders, sera and peripheral blood mononuclear cells (PBMC) from 16 males with AIDS virus infections were examined for the presence of HBV DNA by DNA X DNA blot hybridization. Fifteen (94%) of these individuals had serologic evidence of a recent or prior HBV infection. HBV DNA was detected in the PBMC of all of these patients, regardless of existing HBV serology. Among the 36 control individuals without AIDS-related symptomatology, PBMC-associated HBV DNA was detected in 8 of 14 carriers of hepatitis B surface antigen (HBsAg) and in 3 of 10 individuals immune to HBV, but it was absent from the PBMC of 12 individuals without HBV infection. In all instances, the HBV DNA was extrachromosomal and existed as replicative intermediates or high molecular weight oligomers of the viral genome. Replicative intermediates and serum-associated HBV DNA were detected in all hepatitis B e antigen-positive carriers, regardless of their clinical status. In contrast, the high molecular weight oligomers of HBV DNA were detected in the PBMC of all of the AIDS virus-infected patients examined, but in only 33% of those in the control group who had evidence of HBV infection. This finding suggests that a unique and complex HBV-host-cell interaction exists in patients infected with the AIDS virus.

  10. Rapid evolution of recombinant Saccharomyces cerevisiae for Xylose fermentation through formation of extra-chromosomal circular DNA.

    PubMed

    Demeke, Mekonnen M; Foulquié-Moreno, María R; Dumortier, Françoise; Thevelein, Johan M

    2015-03-01

    Circular DNA elements are involved in genome plasticity, particularly of tandem repeats. However, amplifications of DNA segments in Saccharomyces cerevisiae reported so far involve pre-existing repetitive sequences such as ribosomal DNA, Ty elements and Long Terminal Repeats (LTRs). Here, we report the generation of an eccDNA, (extrachromosomal circular DNA element) in a region without any repetitive sequences during an adaptive evolution experiment. We performed whole genome sequence comparison between an efficient D-xylose fermenting yeast strain developed by metabolic and evolutionary engineering, and its parent industrial strain. We found that the heterologous gene XylA that had been inserted close to an ARS sequence in the parent strain has been amplified about 9 fold in both alleles of the chromosomal locus of the evolved strain compared to its parent. Analysis of the amplification process during the adaptive evolution revealed formation of a XylA-carrying eccDNA, pXI2-6, followed by chromosomal integration in tandem arrays over the course of the evolutionary adaptation. Formation of the eccDNA occurred in the absence of any repetitive DNA elements, probably using a micro-homology sequence of 8 nucleotides flanking the amplified sequence. We isolated the pXI2-6 eccDNA from an intermediate strain of the evolutionary adaptation process, sequenced it completely and showed that it confers high xylose fermentation capacity when it is transferred to a new strain. In this way, we have provided clear evidence that gene amplification can occur through generation of eccDNA without the presence of flanking repetitive sequences and can serve as a rapid means of adaptation to selection pressure.

  11. Rapid Evolution of Recombinant Saccharomyces cerevisiae for Xylose Fermentation through Formation of Extra-chromosomal Circular DNA

    PubMed Central

    Demeke, Mekonnen M.; Foulquié-Moreno, María R.; Dumortier, Françoise; Thevelein, Johan M.

    2015-01-01

    Circular DNA elements are involved in genome plasticity, particularly of tandem repeats. However, amplifications of DNA segments in Saccharomyces cerevisiae reported so far involve pre-existing repetitive sequences such as ribosomal DNA, Ty elements and Long Terminal Repeats (LTRs). Here, we report the generation of an eccDNA, (extrachromosomal circular DNA element) in a region without any repetitive sequences during an adaptive evolution experiment. We performed whole genome sequence comparison between an efficient D-xylose fermenting yeast strain developed by metabolic and evolutionary engineering, and its parent industrial strain. We found that the heterologous gene XylA that had been inserted close to an ARS sequence in the parent strain has been amplified about 9 fold in both alleles of the chromosomal locus of the evolved strain compared to its parent. Analysis of the amplification process during the adaptive evolution revealed formation of a XylA-carrying eccDNA, pXI2-6, followed by chromosomal integration in tandem arrays over the course of the evolutionary adaptation. Formation of the eccDNA occurred in the absence of any repetitive DNA elements, probably using a micro-homology sequence of 8 nucleotides flanking the amplified sequence. We isolated the pXI2-6 eccDNA from an intermediate strain of the evolutionary adaptation process, sequenced it completely and showed that it confers high xylose fermentation capacity when it is transferred to a new strain. In this way, we have provided clear evidence that gene amplification can occur through generation of eccDNA without the presence of flanking repetitive sequences and can serve as a rapid means of adaptation to selection pressure. PMID:25738959

  12. Topography of arterial circle of the brain in Egyptian spiny mouse (Acomys cahirinus, Desmarest).

    PubMed

    Szczurkowski, A; Kuchinka, J; Nowak, E; Kuder, T

    2007-04-01

    Using stained acryl latex-injected techniques, the arterial circle of the brain in Acomys cahirinus Desmarest was studied. Results revealed an important individual variability of investigated structure. Three morphological variants were found: (1) the lack of typical arterial circle--opened in front and the back side, (2) partial opened at the back side, (3) completely closed arterial circle. This finding is opposed to many species of mammals, including rodents, and especially laboratory mouse. In our point of view, it seems to be a specific character.

  13. Classification and equivariant cohomology of circle actions on 3d manifolds

    NASA Astrophysics Data System (ADS)

    He, Chen

    2017-10-01

    The classification of Seifert manifolds was given in terms of numeric data by Seifert (1933), and then generalized by Raymond (1968) and Orlik and Raymond (1968) to circle actions on closed 3d manifolds. In this paper, we further generalize the classification to circle actions on 3d manifolds with boundaries by adding a numeric parameter and a graph of cycles. Then, we describe the rational equivariant cohomology of 3d manifolds with circle actions in terms of ring, module and vector-space structures. We also compute equivariant Betti numbers and Poincaré series for these manifolds and discuss the equivariant formality.

  14. [Health education based on culture circles].

    PubMed

    Monteiro, Estela Maria Leite Meirelles; Vieira, Neiva Francenely Cunha

    2010-01-01

    This study aims at systematizing with the participants of Culture Circles a proposal of reconstruction of actions of health education that show the necessary competences to the nurses of Family Health Program for a practice in education on critical and reflexive health. It is constituted of a research action, where the researcher based in "Paulo Freire Method" is encouraging debates in eight Culture Circles having the participation of ten nurses. The Circles give them the training of a political conscience , essential to the process of " empowerment " of the health professional in practicing his socio-politics competence. The proposal of achieving the Culture Circles establish a link of complicity between health professionals and communitarian groups with the actions of health promotion.

  15. A Special Circle for Quadratic Equations.

    ERIC Educational Resources Information Center

    Patterson, Walter M.; Lubecke, Andre M.

    1991-01-01

    Discussed is a method of approximating the roots of a quadratic that allows the discovery of relationships between parabolas and circles and between the use of geometry and algebra. Included are the procedure and justification of the method. (KR)

  16. Point and Circle Configurations; A New Theorem.

    ERIC Educational Resources Information Center

    Dorwart, Harold L.

    1988-01-01

    Point and circle configurations are not well known, so Clifford's chain of theorems and Miquel's theorem, whose diagrams exhibit such configurations, are discussed. A new theorem similar to Miquel's is then presented. (MNS)

  17. The experience of meaning in circle dance

    PubMed Central

    Borges da Costa, Ana L.; Cox, Diane L.

    2016-01-01

    ABSTRACT Circle dance, which derives from the tradition of folk dances, is practised worldwide. This article explores the meanings participants attribute to it. In-depth interviews with 39 participants, teachers and coordinators of teacher training programmes from the circle dance network in the United Kingdom were undertaken. Applying a constructivist grounded theory approach, major categories, representing respectively the experiences of circle dance participants, teachers and coordinators, were developed. This article specifically focuses on the first major category, termed “I can't imagine life without it”, which relates to the experience of 22 dancers. From an occupational perspective, the study reveals how participants realise a sense of meaning and satisfaction through engagement in circle dance and the potential contribution of this occupation to well-being. PMID:27366111

  18. Sets that Contain Their Circle Centers

    ERIC Educational Resources Information Center

    Martin, Greg

    2008-01-01

    Say that a subset S of the plane is a "circle-center set" if S is not a subset of a line, and whenever we choose three non-collinear points from S, the center of the circle through those three points is also an element of S. A problem appearing on the Macalester College Problem of the Week website stated that a finite set of points in the plane,…

  19. Sets that Contain Their Circle Centers

    ERIC Educational Resources Information Center

    Martin, Greg

    2008-01-01

    Say that a subset S of the plane is a "circle-center set" if S is not a subset of a line, and whenever we choose three non-collinear points from S, the center of the circle through those three points is also an element of S. A problem appearing on the Macalester College Problem of the Week website stated that a finite set of points in the plane,…

  20. TRE5-A retrotransposition profiling reveals putative RNA polymerase III transcription complex binding sites on the Dictyostelium extrachromosomal rDNA element.

    PubMed

    Spaller, Thomas; Groth, Marco; Glöckner, Gernot; Winckler, Thomas

    2017-01-01

    The amoeba Dictyostelium discoideum has a haploid genome in which two thirds of the DNA encodes proteins. Consequently, the space available for selfish mobile elements to expand without excess damage to the host genome is limited. The non-long terminal repeat retrotransposon TRE5-A maintains an active population in the D. discoideum genome and apparently adapted to this gene-dense environment by targeting positions ~47 bp upstream of tRNA genes that are devoid of protein-coding regions. Because only ~24% of tRNA genes are associated with a TRE5-A element in the reference genome, we evaluated whether TRE5-A retrotransposition is limited to this subset of tRNA genes. We determined that a tagged TRE5-A element (TRE5-Absr) integrated at 384 of 405 tRNA genes, suggesting that expansion of the current natural TRE5-A population is not limited by the availability of targets. We further observed that TRE5-Absr targets the ribosomal 5S gene on the multicopy extrachromosomal DNA element that carries the ribosomal RNA genes, indicating that TRE5-A integration may extend to the entire RNA polymerase III (Pol III) transcriptome. We determined that both natural TRE5-A and cloned TRE5-Absr retrotranspose to locations on the extrachromosomal rDNA element that contain tRNA gene-typical A/B box promoter motifs without displaying any other tRNA gene context. Based on previous data suggesting that TRE5-A targets tRNA genes by locating Pol III transcription complexes, we propose that A/B box loci reflect Pol III transcription complex assembly sites that possess a function in the biology of the extrachromosomal rDNA element.

  1. The linear extrachromosomal DNA of Physarum polycephalum replicates and is maintained under non-selective conditions in two different lower eukaryotes.

    PubMed

    Künzler, P

    1985-03-25

    The slime mould Physarum polycephalum contains 100 to 200 molecules of extrachromosomal linear DNA (PeDNA). Two sets of the 19S and 26S ribosomal genes are located on each molecule of PeDNA. In the nonmitotic phase of the cell cycle PeDNA is localised in the nucleolus. The molecules are maintained throughout vegetative growth. In order to study the signals responsible for its maintenance, PeDNA was purified and introduced into the two distantly related yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe. Surprisingly, intact PeDNA transforms both yeasts with high frequency and PeDNA sequences are maintained in the absence of selective pressure.

  2. Protocol for Isolating the Mouse Circle of Willis.

    PubMed

    Hur, Justine Claire; Blaise, Régis; Limon, Isabelle

    2016-10-22

    The cerebral arterial circle (circulus arteriosus cerebri) or circle of Willis (CoW) is a circulatory anastomosis surrounding the optic chiasma and hypothalamus that supplies blood to the brain and surrounding structures. It has been implicated in several cerebrovascular disorders, including cerebral amyloid angiopathy (CAA)-associated vasculopathies, intracranial atherosclerosis and intracranial aneurysms. Studies of the molecular mechanisms underlying these diseases for the identification of novel drug targets for their prevention require animal models. Some of these models may be transgenic, whereas others will involve isolation of the cerebro-vasculature, including the CoW.The method described here is suitable for CoW isolation in any mouse lineage and has considerable potential for screening (expression of genes, protein production, posttranslational protein modifications, secretome analysis, etc.) studies on the large vessels of the mouse cerebro-vasculature. It can also be used for ex vivo studies, by adapting the organ bath system developed for isolated mouse olfactory arteries.

  3. Physiological and lifestyle factors contributing to risk and severity of peri-orbital dark circles in the Brazilian population*

    PubMed Central

    Matsui, Mary S; Schalka, Sérgio; Vanderover, Garrett; Fthenakis, Christina G.; Christopher, J; Bombarda, Patricia Camarano Pinto; Bueno, Juliana Regina; Viscomi, Bianca Lenci Inácio; Bombarda Júnior, Mário Sérgio

    2015-01-01

    BACKGROUND Peri-orbital dark circles are a cosmetic concern worldwide, and have been attributed to hyperpigmentation from allergy or atopic dermatitis, blood stasis, structural shadowing effects, and a thin epidermis/dermis under the eye. It is of interest to better understand lifestyle and demographic risk factors and the relative impact of melanin, blood and epidermal/dermal factors on the severity of Peri-orbital dark circles. OBJECTIVE To compare by non-invasive imaging the impact of biological factors to a visual grading scale for Peri-orbital dark circles, and test the correlation of various demographic factors with Peri-orbital dark circles. METHODS Subjects completed a lifestyle and health survey, and Peri-orbital dark circles severity was evaluated using standardized photographs. Hyperspectral image analysis was used to assess the contributions of melanin, blood volume, degree of blood oxygen saturation, and dermal scattering. RESULTS Family history was the most significant risk factor for Peri-orbital dark circles. The average age of onset was 24 years, and earlier onset correlated with higher severity scores. Asthma was significantly associated with Peri-orbital dark circles scores, but self-reported allergy was not. In this study, sleep was not correlated with Peri-orbital dark circles scores. Hyperspectral imaging indicated that melanin was the dominant correlate for Peri-orbital dark circles severity, while oxygen saturation was secondary. The difference between under-eye and cheek measurements for ∆L*and ∆E* were the most significant instrumental parameters correlated with visual assessment of Peri-orbital dark circles severity. CONCLUSION Although typically associated with lack of sleep, risk of Peri-orbital dark circles is primarily hereditary. The main factors contributing to the appearance of Peri-orbital dark circles are melanin and (deoxygenated) blood. PMID:26375218

  4. Experiments Testing the Causes of Namibian Fairy Circles

    PubMed Central

    Tschinkel, Walter R.

    2015-01-01

    The grasslands on the sandy soils of the eastern edge of the Namib Desert of Namibia are strikingly punctuated by millions of mostly regularly-spaced circular bare spots 2 to 10 m or more in diameter, generally with a margin of taller grasses. The causes of these so called fairy circles are unknown, but several hypotheses have been advanced. In October 2009, we set up experiments that specifically tested four hypothesized causes, and monitored these 5 times between 2009 and 2015. Grass exclusion in circles due to seepage of subterranean vapors or gases was tested by burying an impermeable barrier beneath fairy circles, but seedling density and growth did not differ from barrier-less controls. Plant germination and growth inhibition by allelochemicals or nutrient deficiencies in fairy circle soils were tested by transferring fairy circle soil to artificially cleared circles in the grassy matrix, and matrix soil to fairy circles (along with circle to circle and matrix to matrix controls). None of the transfers changed the seedling density and growth from the control reference conditions. Limitation of plant growth due to micronutrient depletion within fairy circles was tested by supplementing circles with a micronutrient mixture, but did not result in differences in plant seedling density and growth. Short-range vegetation competitive feedbacks were tested by creating artificially-cleared circles of 2 or 4 m diameter located 2 or 6 m from a natural fairy circle. The natural circles remained bare and the artificial circles revegetated. These four experiments provided evidence that fairy circles were not caused by subterranean vapors, that fairy circle soil per se did not inhibit plant growth, and that the circles were not caused by micronutrient deficiency. There was also no evidence that vegetative feedbacks affected fairy circles on a 2 to 10 m scale. Landscape-scale vegetative self-organization is discussed as a more likely cause of fairy circles. PMID:26510015

  5. Experiments Testing the Causes of Namibian Fairy Circles.

    PubMed

    Tschinkel, Walter R

    2015-01-01

    The grasslands on the sandy soils of the eastern edge of the Namib Desert of Namibia are strikingly punctuated by millions of mostly regularly-spaced circular bare spots 2 to 10 m or more in diameter, generally with a margin of taller grasses. The causes of these so called fairy circles are unknown, but several hypotheses have been advanced. In October 2009, we set up experiments that specifically tested four hypothesized causes, and monitored these 5 times between 2009 and 2015. Grass exclusion in circles due to seepage of subterranean vapors or gases was tested by burying an impermeable barrier beneath fairy circles, but seedling density and growth did not differ from barrier-less controls. Plant germination and growth inhibition by allelochemicals or nutrient deficiencies in fairy circle soils were tested by transferring fairy circle soil to artificially cleared circles in the grassy matrix, and matrix soil to fairy circles (along with circle to circle and matrix to matrix controls). None of the transfers changed the seedling density and growth from the control reference conditions. Limitation of plant growth due to micronutrient depletion within fairy circles was tested by supplementing circles with a micronutrient mixture, but did not result in differences in plant seedling density and growth. Short-range vegetation competitive feedbacks were tested by creating artificially-cleared circles of 2 or 4 m diameter located 2 or 6 m from a natural fairy circle. The natural circles remained bare and the artificial circles revegetated. These four experiments provided evidence that fairy circles were not caused by subterranean vapors, that fairy circle soil per se did not inhibit plant growth, and that the circles were not caused by micronutrient deficiency. There was also no evidence that vegetative feedbacks affected fairy circles on a 2 to 10 m scale. Landscape-scale vegetative self-organization is discussed as a more likely cause of fairy circles.

  6. Magnetic Resonance Angiographic Study of Anatomic Variations of the Circle of Willis in a Population in Tehran.

    PubMed

    Jalali Kondori, Bahman; Azemati, Fateme; Dadseresht, Sonia

    2017-04-01

    The circle of Willis, an anastomotic polygon at the base of the brain, forms an important collateral network to maintain cerebral blood perfusion. The aim of this study was to investigate different anatomic variations of the circle of Willis and their prevalence. This cross-sectional study was conducted on 525 healthy participants including 205 men and 320 women. The mean age of the patients was 51.5 years. Three-dimensional time-of-flight magnetic resonance angiography (3D-TOF MRA) technique was used. Vascular variations in the anterior and posterior parts of the circle were evaluated. The findings show that the complete circle of Willis was visible in a small number of patients. The circle of Willis had a complete vascular structure in 20.9% of the patients. The anterior part of the circle of Willis had a complete structure in 80.95% of the cases, while the posterior part had a complete structure in 20.95% of the cases. We observed wide variations in the circle of Willis configuration in our study. Similar to other studies, most variations are related to the posterior part of the circle of Willis. Absence of bilateral posterior communicating artery variation is more common than other types of variations in this population.

  7. Quality Circle Effectiveness as a Function of Upper-Management Support, Circle Initiation, and Collar Color.

    ERIC Educational Resources Information Center

    Tang, Thomas Li-Ping; And Others

    Japanese management practices have attracted much interest in the United States. The use of quality circles (QCs) common in Japan, has been considered a promising approach to improving Americn workers' productivity. A quality circle is made up of workers from the same group who meet to discuss quality problems, recommend solutions, and implement…

  8. Expanding-Circle Students Learning "Standard English" in the Outer-Circle Asia

    ERIC Educational Resources Information Center

    Kobayashi, Yoko

    2011-01-01

    Drawing upon Kachru's concentric circles of English, the present study explores whether middle-class Japanese students who chose to study English solo at private language schools in Singapore diverge from many others who (wish to) study inner-circle English. The study is stimulated by the repeated interdisciplinary findings that, in spite of the…

  9. Expanding-Circle Students Learning "Standard English" in the Outer-Circle Asia

    ERIC Educational Resources Information Center

    Kobayashi, Yoko

    2011-01-01

    Drawing upon Kachru's concentric circles of English, the present study explores whether middle-class Japanese students who chose to study English solo at private language schools in Singapore diverge from many others who (wish to) study inner-circle English. The study is stimulated by the repeated interdisciplinary findings that, in spite of the…

  10. Attributions of Quality Circles' Failure: Perceptions among Top-Management, Supporting Staff, and Quality Circle Members.

    ERIC Educational Resources Information Center

    Tang, Thomas Li-Ping; Butler, Edie Aguilar

    Quality circles, a management practice that involves groups of workers from the same work area voluntarily meeting on a regular basis to identify, analyze, and solve various work-related problems, have been used in Japan for over 40 years. In the United States, quality circles have been tried in many organizations during the past 2 decades and…

  11. Generic Rigidity for Circle Diffeomorphisms with Breaks

    NASA Astrophysics Data System (ADS)

    Kocić, Saša

    2016-06-01

    We prove that {C^r}-smooth ({r > 2}) circle diffeomorphisms with a break, i.e., circle diffeomorphisms with a single singular point where the derivative has a jump discontinuity, are generically, i.e., for almost all irrational rotation numbers, not {C^{1+\\varepsilon}}-rigid, for any {\\varepsilon > 0}. This result complements our recent proof, joint with Khanin (Geom Funct Anal 24:2002-2028, 2014), that such maps are generically {C^1}-rigid. It stands in remarkable contrast to the result of Yoccoz (Ann Sci Ec Norm Sup 17:333-361, 1984) that {C^r}-smooth circle diffeomorphisms are generically {C^{r-1-κ}}-rigid, for any {κ > 0}.

  12. Gradual regime shifts in fairy circles.

    PubMed

    Zelnik, Yuval R; Meron, Ehud; Bel, Golan

    2015-10-06

    Large responses of ecosystems to small changes in the conditions--regime shifts--are of great interest and importance. In spatially extended ecosystems, these shifts may be local or global. Using empirical data and mathematical modeling, we investigated the dynamics of the Namibian fairy circle ecosystem as a case study of regime shifts in a pattern-forming ecosystem. Our results provide new support, based on the dynamics of the ecosystem, for the view of fairy circles as a self-organization phenomenon driven by water-vegetation interactions. The study further suggests that fairy circle birth and death processes correspond to spatially confined transitions between alternative stable states. Cascades of such transitions, possible in various pattern-forming systems, result in gradual rather than abrupt regime shifts.

  13. Literature Circles Go to College

    ERIC Educational Resources Information Center

    Levy, Ronna J.

    2011-01-01

    In basic writing classrooms and scholarship, reading too often remains invisible; neither research nor established practice provides tangible activities to support reading and connect it to writing. This article documents a search for structured, scaffolded, low-stakes reading activities, a search that moves off the college campus and into the…

  14. Raccoon Circles: A Handbook for Facilitators.

    ERIC Educational Resources Information Center

    Cain, Jim

    This handbook presents a collection of over 35 experiential and adventure-based activities using only a single item of equipment--a 15-foot long section of 1-inch tubular climbing webbing, called a raccoon circle. Some of the activities are quiet, some are loud, and they range from low to high challenge levels. Different-sized groups can be…

  15. Syllable Circles for Pronunciation Learning and Teaching

    ERIC Educational Resources Information Center

    Whipple, John; Cullen, Charlie; Gardiner, Keith; Savage, Tim

    2015-01-01

    Syllable Circles are interactive visualizations representing prominence as a feature in short phrases or multi-syllable words. They were designed for computer-aided pronunciation teaching. This study explores whether and how interactive visualizations can affect language learners' awareness of prominence, or stress, in English pronunciation. The…

  16. Literature Circles: A Collaborative Success Story!

    ERIC Educational Resources Information Center

    Carpinelli, Tish

    2006-01-01

    The key to improving students' attitudes about reading is to expose them to more contemporary literature--books to which they can relate in settings and themes--books that they are more likely to enjoy. This article describes a collaborative literature circles project between an English teacher and a media specialist that was extremely successful…

  17. Circles and the Lines That Intersect Them

    ERIC Educational Resources Information Center

    Clay, Ellen L.; Rhee, Katherine L.

    2014-01-01

    In this article, Clay and Rhee use the mathematics topic of circles and the lines that intersect them to introduce the idea of looking at the single mathematical idea of relationships--in this case, between angles and arcs--across a group of problems. They introduce the mathematics that underlies these relationships, beginning with the questions…

  18. Promoting Staff Support in Schools: Solution Circles

    ERIC Educational Resources Information Center

    Brown, Emma; Henderson, Linda

    2012-01-01

    The Solution Circle (SC) approach is a flexible tool which encourages participants to maintain a positive, creative approach to problem-solving. This project focussed on the introduction of this approach to staff in a primary and a secondary school. The rationale was to implement a problem-solving/discussion tool that would allow staff to utilise…

  19. Community Social Work and the Learning Circle

    ERIC Educational Resources Information Center

    Lavan, Ann

    2008-01-01

    Outlines an approach for introducing students to Community Social Work by use of clear, engaging stated objectives. Approach is called the Learning Circle and was devised as a tool to enhance student participation and to stimulate networking, dialogue and conversation about social work commitment to community intervention and community-based…

  20. The Circle of Learning at Kickapoo.

    ERIC Educational Resources Information Center

    Dupuis, Victor L.; Walker, Margery W.

    1988-01-01

    Describes student-centered curriculum development for grades 7-12 at the Kickapoo Nation School. Discusses the merger of open education concepts and the Circle of Learning philosophy to provide education consistent with American Indian cultural values, but appropriate to functioning in the modern world. (SV)

  1. Mathematics Teachers Circle around Problem Solving

    ERIC Educational Resources Information Center

    Fernandes, Anthony; Koehler, Jacob; Reiter, Harold

    2011-01-01

    Making problem solving a central part of teaching may be challenging to teachers who have limited experiences in learning and teaching mathematics in this way. Math Teachers' Circles were developed with the aim of establishing a "culture of problem solving" among middle school mathematics teachers. This culture could then be carried back into…

  2. Circles and the Lines That Intersect Them

    ERIC Educational Resources Information Center

    Clay, Ellen L.; Rhee, Katherine L.

    2014-01-01

    In this article, Clay and Rhee use the mathematics topic of circles and the lines that intersect them to introduce the idea of looking at the single mathematical idea of relationships--in this case, between angles and arcs--across a group of problems. They introduce the mathematics that underlies these relationships, beginning with the questions…

  3. Inside the Circle: Kehewin Native Education Manual.

    ERIC Educational Resources Information Center

    John, Rosa; And Others

    The book is divided into four sections in a way that ensures seasonal recognition and environmental awareness. Each chapter within the sections begins with one or more oral histories from Native nations relevant to the concepts and ideas covered in that chapter. The student is introduced to the Native perspective through the concept of the circle,…

  4. Literature Circles as Support for Language Development

    ERIC Educational Resources Information Center

    Elhess, Mohamed; Egbert, Joy

    2015-01-01

    There are many instructional approaches for helping English language learners improve both reading comprehension and overall language proficiency. One such approach, the literature circle--which is somewhat like a student book club in the classroom--has drawn a great deal of attention in recent years (Schlick Noe and Johnson 1999). Many teachers…

  5. Quality Circles in the Community College.

    ERIC Educational Resources Information Center

    Cloud, Robert C.

    Background information on the history and use of quality circles is provided in this paper, along with a discussion of the applicability of this management technique to the community college setting. First, introductory material is presented on the development of the approach in the early 1950s, its widespread use in the industrial and business…

  6. Promoting Staff Support in Schools: Solution Circles

    ERIC Educational Resources Information Center

    Brown, Emma; Henderson, Linda

    2012-01-01

    The Solution Circle (SC) approach is a flexible tool which encourages participants to maintain a positive, creative approach to problem-solving. This project focussed on the introduction of this approach to staff in a primary and a secondary school. The rationale was to implement a problem-solving/discussion tool that would allow staff to utilise…

  7. VIEW ACROSS BIRCH CIRCLE, SHOWING PLAYGROUND #1 NEAR DATE DRIVE. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW ACROSS BIRCH CIRCLE, SHOWING PLAYGROUND #1 NEAR DATE DRIVE. VIEW FACING NORTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  8. VIEW OF BIRCH CIRCLE, FROM INTERSECTION WITH DATE DRIVE. VIEW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF BIRCH CIRCLE, FROM INTERSECTION WITH DATE DRIVE. VIEW FACING WEST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  9. VIEW OF NORTHWEST BEND IN BIRCH CIRCLE. VIEW FACING WEST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF NORTHWEST BEND IN BIRCH CIRCLE. VIEW FACING WEST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  10. VIEW OF ELM DRIVE FROM ITS INTERSECTION WITH ELM CIRCLE. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF ELM DRIVE FROM ITS INTERSECTION WITH ELM CIRCLE. VIEW FACING SOUTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  11. The linear extrachromosomal DNA of Physarum polycephalum replicates and is maintained under non-selective conditions in two different lower eukaryotes.

    PubMed Central

    Künzler, P

    1985-01-01

    The slime mould Physarum polycephalum contains 100 to 200 molecules of extrachromosomal linear DNA (PeDNA). Two sets of the 19S and 26S ribosomal genes are located on each molecule of PeDNA. In the nonmitotic phase of the cell cycle PeDNA is localised in the nucleolus. The molecules are maintained throughout vegetative growth. In order to study the signals responsible for its maintenance, PeDNA was purified and introduced into the two distantly related yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe. Surprisingly, intact PeDNA transforms both yeasts with high frequency and PeDNA sequences are maintained in the absence of selective pressure. Images PMID:3889843

  12. Genome sequence of the Leisingera aquimarina type strain (DSM 24565T), a member of the marine Roseobacter clade rich in extrachromosomal elements

    PubMed Central

    Riedel, Thomas; Teshima, Hazuki; Petersen, Jörn; Fiebig, Anne; Davenport, Karen; Daligault, Hajnalka; Erkkila, Tracy; Gu, Wei; Munk, Christine; Xu, Yan; Chen, Amy; Pati, Amrita; Ivanova, Natalia; Goodwin, Lynne A.; Chain, Patrick; Detter, John C.; Rohde, Manfred; Gronow, Sabine; Kyrpides, Nikos C.; Woyke, Tanja; Göker, Markus; Brinkhoff, Thorsten; Klenk, Hans-Peter

    2013-01-01

    Leisingera aquimarina Vandecandelaere et al. 2008 is a member of the genomically well characterized Roseobacter clade within the family Rhodobacteraceae. Representatives of the marine Roseobacter clade are metabolically versatile and involved in carbon fixation and biogeochemical processes. They form a physiologically heterogeneous group, found predominantly in coastal or polar waters, especially in symbiosis with algae, in microbial mats, in sediments or associated with invertebrates. Here we describe the features of L. aquimarina DSM 24565T together with the permanent-draft genome sequence and annotation. The 5,344,253 bp long genome consists of one chromosome and an unusually high number of seven extrachromosomal elements and contains 5,129 protein-coding and 89 RNA genes. It was sequenced as part of the DOE Joint Genome Institute Community Sequencing Program 2010 and of the activities of the Transregional Collaborative Research Centre 51 funded by the German Research Foundation (DFG). PMID:24501625

  13. Enhanced production of hepatitis B surface antigen in NIH 3T3 mouse fibroblasts by using extrachromosomally replicating bovine papillomavirus vector.

    PubMed Central

    Wang, Y; Stratowa, C; Schaefer-Ridder, M; Doehmer, J; Hofschneider, P H

    1983-01-01

    We have constructed a recombinant pBR322 plasmid composed of a subgenomic transforming fragment of bovine papillomavirus DNA and the hepatitis B surface antigen gene from cloned hepatitis B virus DNA and used it for transfection of NIH 3T3 mouse fibroblasts. The transformed cells retain the plasmids in extrachromosomal form with a copy number of about 50 to 100 per cell. Expression of the hepatitis B surface antigen gene linked to bovine papillomavirus DNA is independent of its orientation relative to the bovine papillomavirus vector. Cell lines continuously secreting high amounts of hepatitis B surface antigen into the medium could be established. The antigen is released into the culture medium as 22-nm particles, having the same physical properties and constituent polypeptides as those found in the serum of hepatitis B virus-infected patients. Images PMID:6308420

  14. Circles of Support and Personalization: Exploring the Economic Case

    ERIC Educational Resources Information Center

    Wistow, Gerald; Perkins, Margaret; Knapp, Martin; Bauer, Annette; Bonin, Eva-Maria

    2016-01-01

    Circles of Support aim to enable people with learning disabilities (and others) to live full lives as part of their communities. As part of a wider study of the economic case for community capacity building conducted from 2012 to 2014, we conducted a mixed methods study of five Circles in North West England. Members of these Circles were…

  15. A Spring Playscape Project: Building a Tree Circle

    ERIC Educational Resources Information Center

    Keeler, Rusty

    2009-01-01

    The Tree Circle is a green gathering area for children made by planting trees in a circle. For children, the Tree Circle becomes a magical place for dramatic play, quiet retreat, or lively nature exploration. For teachers and parents it becomes a shady grove for snacks and stories. The trees create a sweet spot that changes during the seasons and…

  16. VIEW OF FACILITY 628 ON BIRCH CIRCLE, ON THE CORNER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF FACILITY 628 ON BIRCH CIRCLE, ON THE CORNER OF CEDAR DRIVE AND BIRCH CIRCLE, ON THE NAVY SIDE OF THE NEIGHBORHOOD. VIEW FACING NORTH/NORTHWEST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  17. Circles of Support and Personalization: Exploring the Economic Case

    ERIC Educational Resources Information Center

    Wistow, Gerald; Perkins, Margaret; Knapp, Martin; Bauer, Annette; Bonin, Eva-Maria

    2016-01-01

    Circles of Support aim to enable people with learning disabilities (and others) to live full lives as part of their communities. As part of a wider study of the economic case for community capacity building conducted from 2012 to 2014, we conducted a mixed methods study of five Circles in North West England. Members of these Circles were…

  18. The "Us" in Discuss: Grouping in Literature Circles

    ERIC Educational Resources Information Center

    Batchelor, Katherine

    2012-01-01

    This article describes one middle school teacher's use of literature circles using heterogeneous grouping. It begins with a brief rationale for using literature circles in the language arts classroom. Next, it describes techniques to form literature circles. Then, it shares how to build and establish a supportive environment within each group. It…

  19. The Acoustic Reality of the Kachruvian Circles: A Rhythmic Perspective

    ERIC Educational Resources Information Center

    Low, Ee Ling

    2010-01-01

    This paper investigates whether the rhythmic properties of varieties of English found in each of the concentric circles of Kachru's model can, in any way, be elucidated by the "Three Circles" model. A measurement and comparison of the rhythm of three varieties of English: British English (from the Inner Circle), Singapore English (from…

  20. A Spring Playscape Project: Building a Tree Circle

    ERIC Educational Resources Information Center

    Keeler, Rusty

    2009-01-01

    The Tree Circle is a green gathering area for children made by planting trees in a circle. For children, the Tree Circle becomes a magical place for dramatic play, quiet retreat, or lively nature exploration. For teachers and parents it becomes a shady grove for snacks and stories. The trees create a sweet spot that changes during the seasons and…

  1. Quality Circles: Involvement, Problem-Solving, and Recognition.

    ERIC Educational Resources Information Center

    Moretz, H. Lynn

    1983-01-01

    The media production department of Central Piedmont Community College (CPCC) began quality circle meetings in January 1981 after studying the process of quality circles and obtaining the understanding and support of the college administration. A quality circle is a small group of people doing similar work who voluntarily meet on a regular basis to…

  2. Origin and evolution of the archaeo-eukaryotic primase superfamily and related palm-domain proteins: structural insights and new members

    PubMed Central

    Iyer, Lakshminarayan M.; Koonin, Eugene V.; Leipe, Detlef D.; Aravind, L.

    2005-01-01

    We report an in-depth computational study of the protein sequences and structures of the superfamily of archaeo-eukaryotic primases (AEPs). This analysis greatly expands the range of diversity of the AEPs and reveals the unique active site shared by all members of this superfamily. In particular, it is shown that eukaryotic nucleo-cytoplasmic large DNA viruses, including poxviruses, asfarviruses, iridoviruses, phycodnaviruses and the mimivirus, encode AEPs of a distinct family, which also includes the herpesvirus primases whose relationship to AEPs has not been recognized previously. Many eukaryotic genomes, including chordates and plants, encode previously uncharacterized homologs of these predicted viral primases, which might be involved in novel DNA repair pathways. At a deeper level of evolutionary connections, structural comparisons indicate that AEPs, the nucleases involved in the initiation of rolling circle replication in plasmids and viruses, and origin-binding domains of papilloma and polyoma viruses evolved from a common ancestral protein that might have been involved in a protein-priming mechanism of initiation of DNA replication. Contextual analysis of multidomain protein architectures and gene neighborhoods in prokaryotes and viruses reveals remarkable parallels between AEPs and the unrelated DnaG-type primases, in particular, tight associations with the same repertoire of helicases. These observations point to a functional equivalence of the two classes of primases, which seem to have repeatedly displaced each other in various extrachromosomal replicons. PMID:16027112

  3. Yoctomole electrochemical genosensing of Ebola virus cDNA by rolling circle and circle to circle amplification.

    PubMed

    Carinelli, S; Kühnemund, M; Nilsson, M; Pividori, M I

    2017-07-15

    This work addresses the design of an Ebola diagnostic test involving a simple, rapid, specific and highly sensitive procedure based on isothermal amplification on magnetic particles with electrochemical readout. Ebola padlock probes were designed to detect a specific L-gene sequence present in the five most common Ebola species. Ebola cDNA was amplified by rolling circle amplification (RCA) on magnetic particles. Further re-amplification was performed by circle-to-circle amplification (C2CA) and the products were detected in a double-tagging approach using a biotinylated capture probe for immobilization on magnetic particles and a readout probe for electrochemical detection by square-wave voltammetry on commercial screen-printed electrodes. The electrochemical genosensor was able to detect as low as 200 ymol, corresponding to 120 cDNA molecules of L-gene Ebola virus with a limit of detection of 33 cDNA molecules. The isothermal double-amplification procedure by C2CA combined with the electrochemical readout and the magnetic actuation enables the high sensitivity, resulting in a rapid, inexpensive, robust and user-friendly sensing strategy that offers a promising approach for the primary care in low resource settings, especially in less developed countries. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Rolling-circle transposons in eukaryotes.

    PubMed

    Kapitonov, V V; Jurka, J

    2001-07-17

    All eukaryotic DNA transposons reported so far belong to a single category of elements transposed by the so-called "cut-and-paste" mechanism. Here, we report a previously unknown category of eukaryotic DNA transposons, Helitron, which transpose by rolling-circle replication. Autonomous Helitrons encode a 5'-to-3' DNA helicase and nuclease/ligase similar to those encoded by known rolling-circle replicons. Helitron-like transposons have conservative 5'-TC and CTRR-3' termini and do not have terminal inverted repeats. They contain 16- to 20-bp hairpins separated by 10--12 nucleotides from the 3'-end and transpose precisely between the 5'-A and T-3', with no modifications of the AT target sites. Together with their multiple diverged nonautonomous descendants, Helitrons constitute approximately 2% of both the Arabidopsis thaliana and Caenorhabditis elegans genomes and also colonize the Oriza sativa genome. Sequence conservation suggests that Helitrons continue to be transposed.

  5. Canadian Quality Circle pilot project in osteoporosis

    PubMed Central

    Ioannidis, George; Papaioannou, Alexandra; Thabane, Lehana; Gafni, Amiram; Hodsman, Anthony; Kvern, Brent; Johnstone, Dan; Plumley, Nathalie; Baldwin, Alanna; Doupe, M.; Katz, Alan; Salach, Lena; Adachi, Jonathan D.

    2007-01-01

    PROBLEM ADDRESSED Family physicians are not adequately following the 2002 Osteoporosis Canada guidelines for providing optimal care to patients with osteoporosis. OBJECTIVE OF PROGRAM The Canadian Quality Circle (CQC) pilot project was developed to assess the feasibility of the CQC project design and to gather informationfor implementing a national study of quality circles (QCs). The national study would assess whether use ofQCs could improve family physicians’ adherence to the osteoporosis guidelines. PROGRAM DESCRIPTION The pilot project enrolled 52 family physicians and involved 7 QCs. The project had 3 phases: training and baseline data collection, educational intervention and follow-up data collection, and sessions on implementing strategies for care. CONCLUSION Findings from the pilot study showed that the CQC project was well designed and well received. Use of QCs appeared to be feasible for transferring knowledge and giving physicians an opportunity to analyze work-related problems and develop solutions to them. PMID:17934033

  6. Function representation with circle inversion map systems

    NASA Astrophysics Data System (ADS)

    Boreland, Bryson; Kunze, Herb

    2017-01-01

    The fractals literature develops the now well-known concept of local iterated function systems (using affine maps) with grey-level maps (LIFSM) as an approach to function representation in terms of the associated fixed point of the so-called fractal transform. While originally explored as a method to achieve signal (and 2-D image) compression, more recent work has explored various aspects of signal and image processing using this machinery. In this paper, we develop a similar framework for function representation using circle inversion map systems. Given a circle C with centre õ and radius r, inversion with respect to C transforms the point p˜ to the point p˜', such that p˜ and p˜' lie on the same radial half-line from õ and d(õ, p˜)d(õ, p˜') = r2, where d is Euclidean distance. We demonstrate the results with an example.

  7. Distortion theorems for polynomials on a circle

    SciTech Connect

    Dubinin, V N

    2000-12-31

    Inequalities for the derivatives with respect to {phi}=arg z the functions ReP(z), |P(z)|{sup 2} and arg P(z) are established for an algebraic polynomial P(z) at points on the circle |z|=1. These estimates depend, in particular, on the constant term and the leading coefficient of the polynomial P(z) and improve the classical Bernstein and Turan inequalities. The method of proof is based on the techniques of generalized reduced moduli.

  8. Critical circle maps and thermodynamic formalism

    NASA Astrophysics Data System (ADS)

    Poshokhodjaeva, Gulnora

    2017-03-01

    Let Xk be the space of analytic, critical circle homeomorphisms with an irrational rotation number ρk = [k, k,…, k,…]. It is shown [S. Ostlund, D. Rand, J. Sethna and E. Siggia, Physica D,8 (1983) 303] that, the renormalization operator ℛ defined on Xk has a unique fixed point T 0. In this paper, we study the properties of orbits of a critical point and build a potential for T 0.

  9. Rolling circle amplification of metazoan mitochondrialgenomes

    SciTech Connect

    Simison, W. Brian; Lindberg, D.R.; Boore, J.L.

    2005-07-31

    Here we report the successful use of rolling circle amplification (RCA) for the amplification of complete metazoan mt genomes to make a product that is amenable to high-throughput genome sequencing techniques. The benefits of RCA over PCR are many and with further development and refinement of RCA, the sequencing of organellar genomics will require far less time and effort than current long PCR approaches.

  10. The role of vision in repetitive circle drawing.

    PubMed

    Zelaznik, H N; Lantero, D

    1996-06-01

    In the present experiment the role of vision in the control of repetitive circular movements was examined. Subjects drew circles at a 600 ms per circle rate. During the first nine seconds of the trial subjects moved with full vision and were paced by a metronome. During the latter 15 seconds, vision could be removed and/or the pacing signal could be removed. There were no effects of the pacing signal on the temporal and spatial characteristics of the circle. Withdrawal of vision did not affect the shape of the circle, but did change its scaler quality. The circles became smaller and the center drifted in a systematic fashion. Furthermore, the loss of vision produced an increase in variability in the circle shape, size and location. It is clear that in a simple task such as circle drawing, vision serves not as a source of information about form, but to maintain a stable and consistent form.

  11. Does the Value Circle Exist Within Persons or Only Across Persons?

    PubMed

    Borg, Ingwer; Bardi, Anat; Schwartz, Shalom H

    2017-04-01

    This study tests whether the Schwartz (1992) value circle exists within individuals, not only across individuals, thereby providing evidence for the within-person rationale underlying the value circle. We analyze responses from five samples (a representative sample in Britain, a general population sample in the United States, and university students in Britain and Iran) varying in value measures of the Schwartz value theory (SVS, PVQ40, PVQ21). An unfolding model is used to map each person's value profile into a two-dimensional space representing both persons and values. In all samples, clear value circles were found, with values ordered around the circle largely according to the theory. The model also represents most individuals well. The value circle exists within individuals, providing strong support for the underlying within-person rationale for the Schwartz (1992) value theory. The unfolding analysis allows identifying which persons fit the model less well and in which way, identifying how meaningful subgroups differ in their value profiles, and testing whether meaningful subgroups have different value structures. The model opens up many new possibilities for research linking values to other variables.

  12. Rolling-circle replication of mitochondrial DNA in the higher plant Chenopodium album (L.).

    PubMed Central

    Backert, S; Dörfel, P; Lurz, R; Börner, T

    1996-01-01

    The mitochondrial genomes of higher plants are larger and more complex than those of all other groups of organisms. We have studied the in vivo replication of chromosomal and plasmid mitochondrial DNAs prepared from a suspension culture and whole plants of the dicotyledonous higher plant Chenopodium album (L.). Electron microscopic studies revealed sigma-shaped, linear, and open circular molecules (subgenomic circles) of variable size as well as a minicircular plasmid of 1.3 kb (mp1). The distribution of single-stranded mitochondrial DNA in the sigma structures and the detection of entirely single-stranded molecules indicate a rolling-circle type of replication of plasmid mp1 and subgenomic circles. About half of the sigma-like molecules had tails exceeding the lengths of the corresponding circle, suggesting the formation of concatemers. Two replication origins (nicking sites) could be identified on mpl by electron microscopy and by a new approach based on the mapping of restriction fragments representing the identical 5' ends of the tails of sigma-like molecules. These data provide, for the first time, evidence for a rolling-circle mode of replication in the mitochondria of higher plants. PMID:8887658

  13. The symmetric elliptic and hyperbolic restricted 3-body problem on the unit circle

    NASA Astrophysics Data System (ADS)

    Luis, Franco-Pérez; Ernesto, Pérez-Chavela

    2016-01-01

    We study the restricted 3-body problem with the constriction of motion to the unit circle. First, we study the 2-body problem on the unit circle and give the explicit solutions for a regularized version of the equations of motion for any initial data. We classify the motions in elliptic, parabolic, hyperbolic type and an equilibrium state. Then, we analyze the restricted 3-body problem on the unit circle when the primary bodies are performing elliptic and hyperbolic motions. We show the existence of just one equilibrium state when the masses of primary bodies are equal and we exhibit the hyperbolic structure of this equilibrium point via an exponential dichotomy. In the last part we regularize the equations of motion. We show the global dynamics and some periodic solutions with its respective period.

  14. The Life Cycle and Life Span of Namibian Fairy Circles

    PubMed Central

    Tschinkel, Walter R.

    2012-01-01

    In Namibia of southwestern Africa, the sparse grasslands that develop on deep sandy soils under rainfall between 50 and 100 mm per annum are punctuated by thousands of quasi-circular bare spots, usually surrounded by a ring of taller grass. The causes of these so-called “fairy circles” are unknown, although a number of hypotheses have been proposed. This paper provides a more complete description of the variation in size, density and attributes of fairy circles in a range of soil types and situations. Circles are not permanent; their vegetative and physical attributes allow them to be arranged into a life history sequence in which circles appear (birth), develop (mature) and become revegetated (die). Occasionally, they also enlarge. The appearance and disappearance of circles was confirmed from satellite images taken 4 years apart (2004, 2008). The frequency of births and deaths as a fraction of the total population of circles allowed the calculation of an approximate turnover rate, and from this, an estimate of circle lifespan. Lifespan appeared to vary with circle size, with small circles averaging about 24 years, and larger ones 43–75 years. Overall lifespan averaged about 41 yr. A second, independent estimate of lifespan was made by revisiting circles 2 to 9 years after their clear status had been confirmed. This resulted in a lifespan estimate of about 60 years. Any causal explanation of fairy circles must include their birth, development and death, their mean lifespan and the variation of their features under different conditions. PMID:22761663

  15. The rolling-circle melting-pot model for porcine circovirus DNA replication

    USDA-ARS?s Scientific Manuscript database

    A stem-loop structure, formed by a pair of inverted repeats during DNA replication, is a conserved feature at the origin of DNA replication (Ori) among plant and animal viruses, bacteriophages and plasmids that replicate their genomes via the rolling-circle replication (RCR) mechanism. Porcine circo...

  16. Expanding Circles within the Outer Circle: The Rural Kisii in Kenya

    ERIC Educational Resources Information Center

    Michieka, Martha M.

    2009-01-01

    This paper evaluates a range of factors that have contributed to the limited spread of English to rural Kisii, Kenya, making the presence of English in this non-urban context fall closer to an English as a Foreign Language (EFL) or Expanding Circle continuum than to the expected English as a Second Language (ESL) context. Kenya is an Outer Circle…

  17. Attributions of Quality Circles' Failure: Differences among Top Management, Supporting Staff, and Quality Circle Members.

    ERIC Educational Resources Information Center

    Tang, Thomas Li-Ping; Butler, Edie Aguilar

    For the past two decades, Japanese management practices have attracted a great deal of attention in the United States. Quality Circles (QCs) have been considered to be one of the most promising approaches to improving American workers' productivity. QCs are defined as small groups of employees from the same work area who meet to identify, analyze,…

  18. The arithmetic of elliptic fibrations in gauge theories on a circle

    NASA Astrophysics Data System (ADS)

    Grimm, Thomas W.; Kapfer, Andreas; Klevers, Denis

    2016-06-01

    The geometry of elliptic fibrations translates to the physics of gauge theories in F-theory. We systematically develop the dictionary between arithmetic structures on elliptic curves as well as desingularized elliptic fibrations and symmetries of gauge theories on a circle. We show that the Mordell-Weil group law matches integral large gauge transformations around the circle in Abelian gauge theories and explain the significance of Mordell-Weil torsion in this context. We also use Higgs transitions and circle large gauge transformations to introduce a group law for genus-one fibrations with multi-sections. Finally, we introduce a novel arithmetic structure on elliptic fibrations with non-Abelian gauge groups in F-theory. It is defined on the set of exceptional divisors resolving the singularities and divisor classes of sections of the fibration. This group structure can be matched with certain integral non-Abelian large gauge transformations around the circle when studying the theory on the lower-dimensional Coulomb branch. Its existence is required by consistency with Higgs transitions from the non-Abelian theory to its Abelian phases in which it becomes the Mordell-Weil group. This hints towards the existence of a new underlying geometric symmetry.

  19. Circle actions on almost complex manifolds with isolated fixed points

    NASA Astrophysics Data System (ADS)

    Jang, Donghoon

    2017-09-01

    In Jang (2014), the author proves that if the circle acts symplectically on a compact, connected symplectic manifold M with three fixed points, then M is equivariantly symplectomorphic to some standard action on CP2. In this paper, we extend the result to a circle action on an almost complex manifold; if the circle acts on a compact, connected almost complex manifold M with exactly three fixed points, then dim M = 4. Moreover, the weights at the fixed points agree with those of a standard circle action on the complex projective plane CP2. Also, we deal with the cases of one fixed point and two fixed points.

  20. Existence of Chimera State on Two Parallel Circles

    NASA Astrophysics Data System (ADS)

    Lin, Larry; Yang, Pei-Kun

    2016-06-01

    A nonlocal coupling system with oscillators on two parallel circles can evolve into a chimera state for suitable values of the parameters α and β. The parameter β is the distance between the circles and affects the phase-locked areas of the chimera state. The Kuramoto theory successfully describes whether and where the oscillators are phase-locked or drifting. The position difference ΔX describes the displacement of phase-locked areas between the circles. The dynamics of the model with four oscillators also show similar phenomena. The position difference ΔX results from the arrangement of oscillators on the two parallel circles.

  1. GENERATING FRACTAL PATTERNS BY USING p-CIRCLE INVERSION

    NASA Astrophysics Data System (ADS)

    Ramírez, José L.; Rubiano, Gustavo N.; Zlobec, Borut Jurčič

    2015-10-01

    In this paper, we introduce the p-circle inversion which generalizes the classical inversion with respect to a circle (p = 2) and the taxicab inversion (p = 1). We study some basic properties and we also show the inversive images of some basic curves. We apply this new transformation to well-known fractals such as Sierpinski triangle, Koch curve, dragon curve, Fibonacci fractal, among others. Then we obtain new fractal patterns. Moreover, we generalize the method called circle inversion fractal be means of the p-circle inversion.

  2. Time-lapse ultrashort pulse microscopy of infection in three-dimensional versus two-dimensional culture environments reveals enhanced extra-chromosomal virus replication compartment formation

    NASA Astrophysics Data System (ADS)

    Gibbs, Holly C.; Sing, Garwin; Armas, Juan Carlos González; Campbell, Colin J.; Ghazal, Peter; Yeh, Alvin T.

    2013-03-01

    The mechanisms that enable viruses to harness cellular machinery for their own survival are primarily studied in cell lines cultured in two-dimensional (2-D) environments. However, there are increasing reports of biological differences between cells cultured in 2-D versus three-dimensional (3-D) environments. Here we report differences in host-virus interactions based on differences in culture environment. Using ultrashort pulse microscopy (UPM), a form of two-photon microscopy that utilizes sub-10-fs pulses to efficiently excite fluorophores, we have shown that de novo development of extra-chromosomal virus replication compartments (VRCs) upon murine cytomegalovirus (mCMV) infection is markedly enhanced when host cells are cultured in 3-D collagen gels versus 2-D monolayers. In addition, time-lapse imaging revealed that mCMV-induced VRCs have the capacity to grow by coalescence. This work supports the future potential of 3-D culture as a useful bridge between traditional monolayer cultures and animal models to study host-virus interactions in a more physiologically relevant environment for the development of effective anti-viral therapeutics. These advances will require broader adoption of modalities, such as UPM, to image deep within scattering tissues.

  3. Modeling biogeophysical interactions in nonsorted circles in the Low Arctic

    NASA Astrophysics Data System (ADS)

    Nicolsky, D. J.; Romanovsky, V. E.; Tipenko, G. S.; Walker, D. A.

    2008-09-01

    We investigate biogeophysical processes that cause differential frost heave in nonsorted circles north of the Alaska's Brooks Range. The main objective is the development of a numerical thermo-mechanical model of a nonsorted circle. The presented model includes mass, momentum and energy conservation laws for water, ice and soil. We applied this model to simulate differential frost heave at the Franklin Bluffs site and obtained a good quantitative agreement with measured dynamics of soil temperature, water content, and frost heave. For other locations such as at the Sagwon Hills and Howe Island sites we obtained qualitative agreement with frost-heave measurements. Sensitivity analysis shows that the most active development of differential frost heave occurs for nonsorted circles within waterlogged areas, as observed in field measurements. For well drained sites, model results and field observations show that the differential frost heave is much smaller in magnitude comparing to that of the water-logged sites. Sensitivity of the model to alternation of the vegetation cover shows that a strong heterogeneity in the vegetation cover promotes active development of the differential frost heave. For nonsorted circles with vegetation on top of the circle, the computed differential heave is less pronounced. The radius of the nonsorted circle influences the magnitude of the frost heave. The computed maximum frost heave in the center of the circle corresponds to 1-1.5 meter diameter nonsorted circles. For nonsorted circles with larger diameters, computed frost heave in the center of a circle is smaller compared to the heave at the circle circumference.

  4. Neurodynamics in Randomly Coupled Circle Maps

    NASA Astrophysics Data System (ADS)

    Matsuno, Tetsuya; Toko, Kiyoshi; Yamafuji, Kaoru

    1996-05-01

    The dynamics of retrieval processes in a system composed of coupled circle maps is studied by means of a statistical method and numerical simulations. Phase patterns are embedded in coupling parameters so that the system may work as an associative memory system. A parameter, which is an amplification factor multiplied to all the coupling strengths, is introduced for investigating the effect of the strength of the coupling nonlinearity on the behavior of the system concerned. The statistical method provides a set of time evolution equations representing the macroscopic behavior. It is found that the storage capacity is considerably enhanced by the introduced amplification factor. It is also shown that the system exhibits macroscopic chaotic oscillations when the strength of the coupling is sufficiently large. Moreover, the clustering is observed, as in other types of the globally coupled nonlinear systems.

  5. Controlled Microwave Heating Accelerates Rolling Circle Amplification.

    PubMed

    Yoshimura, Takeo; Suzuki, Takamasa; Mineki, Shigeru; Ohuchi, Shokichi

    2015-01-01

    Rolling circle amplification (RCA) generates single-stranded DNAs or RNA, and the diverse applications of this isothermal technique range from the sensitive detection of nucleic acids to analysis of single nucleotide polymorphisms. Microwave chemistry is widely applied to increase reaction rate as well as product yield and purity. The objectives of the present research were to apply microwave heating to RCA and indicate factors that contribute to the microwave selective heating effect. The microwave reaction temperature was strictly controlled using a microwave applicator optimized for enzymatic-scale reactions. Here, we showed that microwave-assisted RCA reactions catalyzed by either of the four thermostable DNA polymerases were accelerated over 4-folds compared with conventional RCA. Furthermore, the temperatures of the individual buffer components were specifically influenced by microwave heating. We concluded that microwave heating accelerated isothermal RCA of DNA because of the differential heating mechanisms of microwaves on the temperatures of reaction components, although the overall reaction temperatures were the same.

  6. Physical inactivity and obesity: A vicious circle

    PubMed Central

    Pietiläinen, Kirsi H; Kaprio, Jaakko; Borg, Patrik; Plasqui, Guy; Yki-Järvinen, Hannele; Kujala, Urho M.; Rose, Richard J; Westerterp, Klaas R; Rissanen, Aila

    2007-01-01

    Objective Physical activity (PA) begins to decline in adolescence with concomitant increase in weight. We hypothesized that a vicious circle may arise between decreasing physical activity and weight gain from adolescence to early adulthood. Research Methods and Procedures PA and self-perceived physical fitness assessed in adolescence (16-18 years) were used to predict the development of obesity (BMI≥30 kg/m2) and abdominal obesity (waist≥88 cm in females and ≥102 cm in males) at age 25 in 4240 twin individuals (90% of twins born in Finland 1975-1979). Ten 25-year-old monozygotic (MZ) twin pairs discordant for obesity (16 kg weight difference) were then carefully evaluated for current PA (triaxial accelerometer), total energy expenditure (TEE, doubly labeled water), and basal metabolic rate (BMR, indirect calorimetry). Results Physical inactivity in adolescence strongly predicted the risk of obesity (OR 3.9, 95%CI 1.4-10.9) and abdominal obesity (4.8, 1.9-12.0) at age 25, even after adjusting for baseline and current BMI. Poor physical fitness in adolescence also increased the risk of overall (5.1, 2.0-12.7) and abdominal obesity (3.2, 1.5-6.7) in adulthood. Physical inactivity was both causative and secondary to the development of obesity discordance in the MZ pairs. TEE did not differ between the MZ co-twins. PA levels were lower whereas BMR was higher in the obese co-twins. Discussion Physical inactivity in adolescence strongly and independently predicts total and especially abdominal obesity in young adulthood, favoring the development of a self-perpetuating vicious circle of obesity and physical inactivity. Physical (in)activity should be a major target of obesity prevention in the young. PMID:18239652

  7. Kachru's Three Concentric Circles and English Teaching Fallacies in EFL and ESL Contexts

    ERIC Educational Resources Information Center

    Xiaoqiong, Betsy Hu; Xianxing, Jiang

    2011-01-01

    This paper attempts to introduce and explain the famous Three Concentric Circles proposed by Kachru, namely, the Inner Circle, the Outer Circle and the Expanding Circle. Based on Kachru's theory, the paper proceeds to discuss four fallacies in EFL and ESL contexts, which are (1) English learners in the Outer and Expanding Circles learn English…

  8. The Japanese Quality Control Circle: Why It Works.

    ERIC Educational Resources Information Center

    Watanabe, Susumu

    1991-01-01

    The competitiveness of Japanese industry is in part because of their quality circles. Despite the West's interest in most Japanese business practices, quality circles have been difficult to transplant. This may be a result of misconceptions about their nature and the erroneous idea that workers' motivation is sociocultural, whereas in fact it is…

  9. Growing a Circle of Courage Culture: One School's Journey

    ERIC Educational Resources Information Center

    Espiner, Deborah; Guild, Diane

    2010-01-01

    Mt. Richmond Special School is the first Circle of Courage school in New Zealand. The school reflects the richness of the cultural and learning diversity found in many New Zealand schools. Located in the heart of South Auckland, the school's 130 students represent a wide range of ethnic backgrounds. The universal values in the Circle of Courage…

  10. 29 CFR 1620.26 - Red circle rates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 4 2010-07-01 2010-07-01 false Red circle rates. 1620.26 Section 1620.26 Labor Regulations Relating to Labor (Continued) EQUAL EMPLOYMENT OPPORTUNITY COMMISSION THE EQUAL PAY ACT § 1620.26 Red circle rates. (a) The term “red circle” rate is used to describe certain unusual, higher than normal...

  11. 29 CFR 1620.26 - Red circle rates.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 4 2013-07-01 2013-07-01 false Red circle rates. 1620.26 Section 1620.26 Labor Regulations Relating to Labor (Continued) EQUAL EMPLOYMENT OPPORTUNITY COMMISSION THE EQUAL PAY ACT § 1620.26 Red circle rates. (a) The term “red circle” rate is used to describe certain unusual, higher than normal...

  12. VIEW OF ELM CIRCLE, FROM BETWEEN FACILITIES 750 AND 750. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF ELM CIRCLE, FROM BETWEEN FACILITIES 750 AND 750. VIEW FACING EAST/NORTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  13. VIEW OF PLAYGROUND #3 ON SOUTHERN PORTION OF BIRCH CIRCLE, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF PLAYGROUND #3 ON SOUTHERN PORTION OF BIRCH CIRCLE, SHOWING BENCH AND DRINKING FOUNTAIN. VIEW FACING NORTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  14. VIEW OF DATE DRIVE, FROM INTERSECTION WITH BIRCH CIRCLE, WITH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF DATE DRIVE, FROM INTERSECTION WITH BIRCH CIRCLE, WITH FACILITY 809 ON LEFT, 816 ON RIGHT. NOTE THE MANY DATE PALMS. VIEW FACING NORTHWEST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  15. VIEW OF PLAYGROUND #4 NEAR ELM CIRCLE, SHOWING PICNIC TABLE. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF PLAYGROUND #4 NEAR ELM CIRCLE, SHOWING PICNIC TABLE. VIEW FACING EAST/NORTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  16. VIEW OF BIRCH CIRCLE FROM ITS INTERSECTION WITH CEDAR DRIVE, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF BIRCH CIRCLE FROM ITS INTERSECTION WITH CEDAR DRIVE, ON THE MARINE SIDE OF THE NEIGHBORHOOD. RESIDENTIAL TOWER VISIBLE ON FAR RIGHT. VIEW FACING EAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  17. VIEW OF BIRCH CIRCLE, SHOWING SEGMENT WHICH FORMS THE WESTERNMOST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF BIRCH CIRCLE, SHOWING SEGMENT WHICH FORMS THE WESTERNMOST BOUNDARY OF THE NEIGHBORHOOD. VIEW FACING NORTH/NORTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  18. VIEW OF BACKYARD AREA BEHIND FACILITIES 529 (BIRCH CIRCLE) AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF BACKYARD AREA BEHIND FACILITIES 529 (BIRCH CIRCLE) AND 606 (CEDAR DRIVE). VIEW FACING SOUTHWEST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  19. Study Circles and the Dialogue to Change Program

    ERIC Educational Resources Information Center

    Brennan, Mary; Brophy, Mark

    2010-01-01

    The origins of study circles can be traced back to the Chautauqua movement in the USA in the late nineteenth century. However, interest diminished in the USA and the Swedes discovered and enthusiastically imported the study circle idea as a remedy to their problems of poverty and illiteracy and to educate the broadest possible spectrum of society…

  20. VIEW OF THE OUTER RING OF CENTER CIRCLE, LOOKING NORTH. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF THE OUTER RING OF CENTER CIRCLE, LOOKING NORTH. GRANITE COPING DEFINES THE SWAIN FAMILY PLOT, WHICH CONTAINS A CELTIC CROSS, ON WHICH THE CIRCLE REFERS TO ETERNAL LIFE, AND A RECLINING HUMAN FIGURE IN ETERNAL SLEEP - Woodlands Cemetery, 4000 Woodlands Avenue, Philadelphia, Philadelphia County, PA

  1. An Effective Time and Management Strategy in Quality Circles.

    ERIC Educational Resources Information Center

    Halverson, Don E.

    Contending that participation in quality circles enhances effective time management by school administrators and teachers, this guide provides both a theoretical briefing and practical recommendations for better time management. A pre- posttest prefaces a review of basic concepts of quality circles with reference to the work of Abraham Maslow,…

  2. The Japanese Quality Control Circle: Why It Works.

    ERIC Educational Resources Information Center

    Watanabe, Susumu

    1991-01-01

    The competitiveness of Japanese industry is in part because of their quality circles. Despite the West's interest in most Japanese business practices, quality circles have been difficult to transplant. This may be a result of misconceptions about their nature and the erroneous idea that workers' motivation is sociocultural, whereas in fact it is…

  3. Participation and Gender in Circle-Time Situations in Preschool

    ERIC Educational Resources Information Center

    Emilson, Anette; Johansson, Eva

    2013-01-01

    This study sought to investigate participatory values in relation to gender, as expressed in interactions between teachers and children in circle-time situations in Swedish and Norwegian preschools. This paper reports evidence from three research questions: How is children's participation conditioned in circle-time situations? How are…

  4. Quality Circles: Applications in Vocational Education. Information Series No. 249.

    ERIC Educational Resources Information Center

    Lloyd, Russell F.; Rehg, Virgil R.

    A strategy for increasing worker participation in an effort to remedy the problems of declining productivity and quality is the quality circles concept. The quality circles process involves small groups of employees who meet voluntarily on a regular basis to identify, analyze, and develop solutions to problems and to implement the solutions when…

  5. Integrating Literature Circles into a Cotaught Inclusive Classroom

    ERIC Educational Resources Information Center

    Whittaker, Catharine R.

    2012-01-01

    Literature circles or book clubs are small, heterogeneous groups of students who have chosen to read and discuss the same book together. The research on literature circles suggests that they hold great promise for increasing students' enjoyment of reading and honing their literacy skills. When evidence-based strategies are embedded into a…

  6. Growing a Circle of Courage Culture: One School's Journey

    ERIC Educational Resources Information Center

    Espiner, Deborah; Guild, Diane

    2010-01-01

    Mt. Richmond Special School is the first Circle of Courage school in New Zealand. The school reflects the richness of the cultural and learning diversity found in many New Zealand schools. Located in the heart of South Auckland, the school's 130 students represent a wide range of ethnic backgrounds. The universal values in the Circle of Courage…

  7. Empowerment of Children through Circle Time: Myth or Reality?

    ERIC Educational Resources Information Center

    Collins, Bernie

    2013-01-01

    The focus of this paper is circle time, a widely used method in primary schools in Ireland and elsewhere. It involves children sitting in a circle with their teacher using method-specific techniques and strategies for self-esteem enhancement, promoting positive relationships and development of social skills. Qualitative research was undertaken in…

  8. Participation and Gender in Circle-Time Situations in Preschool

    ERIC Educational Resources Information Center

    Emilson, Anette; Johansson, Eva

    2013-01-01

    This study sought to investigate participatory values in relation to gender, as expressed in interactions between teachers and children in circle-time situations in Swedish and Norwegian preschools. This paper reports evidence from three research questions: How is children's participation conditioned in circle-time situations? How are…

  9. The Sacred Circle: A Process Pedagogy of Healing.

    ERIC Educational Resources Information Center

    Regnier, Robert

    1994-01-01

    The process pedagogy proposed here, based on Canadian Plains Indians' Sacred Circle teaching and educational practices at an aboriginal high school, views healing as transition toward meaning, wholeness, connectedness, and balance. The paper examines Whitehead's criticism of western metaphysics, the Sacred Circle as expression of aboriginal…

  10. An Effective Time and Management Strategy in Quality Circles.

    ERIC Educational Resources Information Center

    Halverson, Don E.

    Contending that participation in quality circles enhances effective time management by school administrators and teachers, this guide provides both a theoretical briefing and practical recommendations for better time management. A pre- posttest prefaces a review of basic concepts of quality circles with reference to the work of Abraham Maslow,…

  11. Using Social Psychology To Make Quality Circles More Effective.

    ERIC Educational Resources Information Center

    Smither, Robert D.

    Quality circles have proliferated in organizations throughout the 1980s, but their success depends on careful planning and monitoring, and on an awareness of social psychology and group dynamics. This presentation accordingly evaluates some of the assumptions of the literature on quality circles and suggests ways in which social psychology…

  12. Empowerment of Children through Circle Time: Myth or Reality?

    ERIC Educational Resources Information Center

    Collins, Bernie

    2013-01-01

    The focus of this paper is circle time, a widely used method in primary schools in Ireland and elsewhere. It involves children sitting in a circle with their teacher using method-specific techniques and strategies for self-esteem enhancement, promoting positive relationships and development of social skills. Qualitative research was undertaken in…

  13. DETAIL VIEW OF PIEDMONT AVENUE TRAFFIC CIRCLE AT INTERSECTION OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL VIEW OF PIEDMONT AVENUE TRAFFIC CIRCLE AT INTERSECTION OF CHANNING WAY. SEEN FROM EAST SIDE OF CIRCLE LOOKING NORTH AT 2395 PIEDMONT, SIGMA PI HOUSE BY FREDERICK H. REIMERS, 1928. Photograph by Brian Grogan, July 8, 2007 - Piedmont Way & the Berkeley Property Tract, East of College Avenue between Dwight Way & U.C. Memorial Stadium, Berkeley, Alameda County, CA

  14. What Works: Study Circles in the Real World. Best Practices for Producing Community-Wide Study Circles.

    ERIC Educational Resources Information Center

    Mengual, Gloria

    This document, which is based on information gathered during a 1998 study of how study circle programs contribute to community problem solving, presents best practices for producing community-wide study circles. The best practices are illustrated through stories that are grouped into five sections on the following themes: (1) creating a…

  15. A Real Time PCR Platform for the Simultaneous Quantification of Total and Extrachromosomal HIV DNA Forms in Blood of HIV-1 Infected Patients

    PubMed Central

    Canovari, Benedetta; Scotti, Maddalena; Acetoso, Marcello; Valentini, Massimo; Petrelli, Enzo; Magnani, Mauro

    2014-01-01

    Background The quantitative measurement of various HIV-1 DNA forms including total, unintegrated and integrated provirus play an increasingly important role in HIV-1 infection monitoring and treatment-related research. We report the development and validation of a SYBR Green real time PCR (TotUFsys platform) for the simultaneous quantification of total and extrachromosomal HIV-1 DNA forms in patients. This innovative technique makes it possible to obtain both measurements in a single PCR run starting from frozen blood employing the same primers and standard curve. Moreover, due to identical amplification efficiency, it allows indirect estimation of integrated level. To specifically detect 2-LTR a qPCR method was also developed. Methodology/Findings Primers used for total HIV-1 DNA quantification spanning a highly conserved region were selected and found to detect all HIV-1 clades of group M and the unintegrated forms of the same. A total of 195 samples from HIV-1 patients in a wide range of clinical conditions were analyzed with a 100% success rate, even in patients with suppressed plasma viremia, regardless of CD4+ or therapy. No significant correlation was observed between the two current prognostic markers, CD4+ and plasma viremia, while a moderate or high inverse correlation was found between CD4+ and total HIV DNA, with strong values for unintegrated HIV DNA. Conclusions/Significance Taken together, the results support the use of HIV DNA as another tool, in addition to traditional assays, which can be used to estimate the state of viral infection, the risk of disease progression and to monitor the effects of ART. The TotUFsys platform allowed us to obtain a final result, expressed as the total and unintegrated HIV DNA copy number per microgram of DNA or 104 CD4+, for 12 patients within two working days. PMID:25364909

  16. Sleep disturbances and PTSD: a perpetual circle?

    PubMed Central

    van Liempt, Saskia

    2012-01-01

    Background Sleep facilitates the consolidation of fear extinction memory. Nightmares and insomnia are hallmark symptoms of posttraumatic stress disorder (PTSD), possibly interfering with fear extinction and compromising recovery. A perpetual circle may develop when sleep disturbances increase the risk for PTSD and vice versa. To date, therapeutic options for alleviating sleep disturbances in PTSD are limited. Methods We conducted three studies to examine the relationship between sleep and posttraumatic symptoms: (1) a prospective longitudinal cohort study examining the impact of pre-deployment insomnia symptoms and nightmares on the development of PTSD; (2) a cross-sectional study examining subjective sleep measures, polysomnography, endocrinological parameters, and memory in veterans with PTSD, veterans without PTSD, and healthy controls (HCs); (3) a randomized controlled trial (RCT) (n=14) comparing the effect of prazosin and placebo on sleep disturbances in veterans with PTSD. In addition to these studies, we systematically reviewed the literature on treatment options for sleep disturbances in PTSD. Results Pre-deployment nightmares predicted PTSD symptoms at 6 months post-deployment; however, insomnia symptoms did not. Furthermore, in patients with PTSD, a correlation between the apnea index and PTSD severity was observed, while obstructive sleep apnea syndrome was not more prevalent. We observed a significant increase in awakenings during sleep in patients with PTSD, which were positively correlated with adrenocorticotropic hormone (ACTH) levels, negatively correlated with growth hormone (GH) secretion, and the subjective perception of sleep depth. Also, heart rate was significantly increased in PTSD patients. Interestingly, plasma levels of GH during the night were decreased in PTSD. Furthermore, GH secretion and awakenings were independent predictors for delayed recall, which was lower in PTSD. In our RCT, prazosin was not associated with improvement of any

  17. Controlled Microwave Heating Accelerates Rolling Circle Amplification

    PubMed Central

    Yoshimura, Takeo; Suzuki, Takamasa; Mineki, Shigeru; Ohuchi, Shokichi

    2015-01-01

    Rolling circle amplification (RCA) generates single-stranded DNAs or RNA, and the diverse applications of this isothermal technique range from the sensitive detection of nucleic acids to analysis of single nucleotide polymorphisms. Microwave chemistry is widely applied to increase reaction rate as well as product yield and purity. The objectives of the present research were to apply microwave heating to RCA and indicate factors that contribute to the microwave selective heating effect. The microwave reaction temperature was strictly controlled using a microwave applicator optimized for enzymatic-scale reactions. Here, we showed that microwave-assisted RCA reactions catalyzed by either of the four thermostable DNA polymerases were accelerated over 4-folds compared with conventional RCA. Furthermore, the temperatures of the individual buffer components were specifically influenced by microwave heating. We concluded that microwave heating accelerated isothermal RCA of DNA because of the differential heating mechanisms of microwaves on the temperatures of reaction components, although the overall reaction temperatures were the same. PMID:26348227

  18. Rolling-circle replication of bacterial plasmids.

    PubMed Central

    Khan, S A

    1997-01-01

    Many bacterial plasmids replicate by a rolling-circle (RC) mechanism. Their replication properties have many similarities to as well as significant differences from those of single-stranded DNA (ssDNA) coliphages, which also replicate by an RC mechanism. Studies on a large number of RC plasmids have revealed that they fall into several families based on homology in their initiator proteins and leading-strand origins. The leading-strand origins contain distinct sequences that are required for binding and nicking by the Rep proteins. Leading-strand origins also contain domains that are required for the initiation and termination of replication. RC plasmids generate ssDNA intermediates during replication, since their lagging-strand synthesis does not usually initiate until the leading strand has been almost fully synthesized. The leading- and lagging-strand origins are distinct, and the displaced leading-strand DNA is converted to the double-stranded form by using solely the host proteins. The Rep proteins encoded by RC plasmids contain specific domains that are involved in their origin binding and nicking activities. The replication and copy number of RC plasmids, in general, are regulated at the level of synthesis of their Rep proteins, which are usually rate limiting for replication. Some RC Rep proteins are known to be inactivated after supporting one round of replication. A number of in vitro replication systems have been developed for RC plasmids and have provided insight into the mechanism of plasmid RC replication. PMID:9409148

  19. Quantizations on the circle and coherent states

    NASA Astrophysics Data System (ADS)

    Chadzitaskos, G.; Luft, P.; Tolar, J.

    2012-06-01

    We present a possible construction of coherent states on the unit circle as configuration space. Our approach is based on Borel quantizations on S1 including the Aharonov-Bohm-type quantum description. Coherent states are constructed by Perelomov’s method as group-related coherent states generated by Weyl operators on the quantum phase space {Z} \\times S^{1}. Because of the duality of canonical coordinates and momenta, i.e. the angular variable and the integers, this formulation can also be interpreted as coherent states over an infinite periodic chain. For the construction, we use the analogy with our quantization and coherent states over a finite periodic chain where the quantum phase space was {Z}_{M} \\times {Z}_{M}. The coherent states constructed in this work are shown to satisfy the resolution of unity. To compare them with canonical coherent states, some of their further properties are also studied demonstrating similarities as well as substantial differences. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Coherent states: mathematical and physical aspects’.

  20. Inhomogeneous field theory inside the arctic circle

    NASA Astrophysics Data System (ADS)

    Allegra, Nicolas; Dubail, Jérôme; Stéphan, Jean-Marie; Viti, Jacopo

    2016-05-01

    Motivated by quantum quenches in spin chains, a one-dimensional toy-model of fermionic particles evolving in imaginary-time from a domain-wall initial state is solved. The main interest of this toy-model is that it exhibits the arctic circle phenomenon, namely a spatial phase separation between a critically fluctuating region and a frozen region. Large-scale correlations inside the critical region are expressed in terms of correlators in a (euclidean) two-dimensional massless Dirac field theory. It is observed that this theory is inhomogenous: the metric is position-dependent, so it is in fact a Dirac theory in curved space. The technique used to solve the toy-model is then extended to deal with the transfer matrices of other models: dimers on the honeycomb and square lattice, and the six-vertex model at the free fermion point (Δ =0 ). In all cases, explicit expressions are given for the long-range correlations in the critical region, as well as for the underlying Dirac action. Although the setup developed here is heavily based on fermionic observables, the results can be translated into the language of height configurations and of the gaussian free field, via bosonization. Correlations close to the phase boundary and the generic appearance of Airy processes in all these models are also briefly revisited in the appendix.

  1. Androgen circle of polycystic ovary syndrome.

    PubMed

    Homburg, Roy

    2009-07-01

    Although the aetiology of polycystic ovary syndrome (PCOS) is still not known and the search for causative genes is proving elusive, it is generally agreed that hyperandrogenism is at the heart of the syndrome. Here, it is proposed that excess androgens are the root cause of PCOS starting from their influence on the female fetus in programming gene expression, producing the characteristic signs and symptoms which are then exacerbated by a propagation of excess ovarian androgen production from multiple small follicles, anovulation and insulin resistance in the reproductive life-span, thus setting up a vicious perpetual circle of androgen excess. This opinion paper, rather than being a full-scale review, is intentionally biased in support of this hypothesis that androgen excess is the 'root of all evil' in PCOS; in the hope that its acceptance could lead to more direct treatment of the syndrome in all its facets rather than the symptomatic treatment of side effects of androgen excess that we are addressing today.

  2. Comparison of the coaxial circle circuit with the conventional circle circuit.

    PubMed

    Mizrak, Ayse; Bilgi, Murat; Koruk, Senem; Ganidagli, Suleyman; Karatas, Erkan; Oner, Unsal; Gul, Rauf; Sahin, Levent

    2011-08-01

    The coaxial circle system helps prevent heat loss during surgery, and it also acts as a humidifier. This study aimed to compare the coaxial breathing system and the conventional system in their ability to warm and moisturize inhaled gases, and we also analyzed lung function protection and saccharin clearance time in patients who underwent tympanomastoidectomy (TMT) with the aid of these two systems. Forty adult patients of ASA physical status I-II were scheduled for elective TMT. A standard volume-dependent ventilator setting was used to establish normocapnia. The coaxial circle system was used in the treated group (n=20), whereas the conventional circuit system was used in the control group (n=20). Saccharin clearance, VC (vital capacity), FRC (functional residual capacity), FEV1 (forced expiratory volume in 1 second), airway pressure, relative humidity and temperature of inspired gas, body temperature and adverse and hemodynamic effects were measured at different perioperative periods. The relative humidity (mg H2O Lt -1) of inspired gas in the treated group was higher than in the control group at 5, 15, 30, 45, 60 and 90 minutes after anesthesia induction. The temperature of inspired gas (Centigrade) in the treated group was higher than in the control group (p<0.05) after 5, 10, 15, 30, 45, and 90 minutes of anesthesia. Postoperative saccharin clearance time was lower than before the operation in the treated group (p<0.05). Postoperative FRC was lower than preoperative FRC in the study and control groups (p<0.05). The coaxial circle system decreased postoperative saccharin clearance time and increased postoperative FRC, relative humidity and the temperature of inspired fresh gas, without any adverse perioperative effects in patients who underwent TMT.

  3. Fair cubic transition between two circles with one circle inside or tangent to the other

    NASA Astrophysics Data System (ADS)

    Dimulyo, Sarpono; Habib, Zulfiqar; Sakai, Manabu

    2009-08-01

    This paper describes a method for joining two circles with a C-shaped and an S-shaped transition curve, composed of a cubic Bézier segment. As an extension of our previous work; we show that a single cubic curve can be used for blending or for a transition curve preserving G 2 continuity regardless of the distance of their centers and magnitudes of the radii which is an advantage. Our method with shape parameter provides freedom to modify the shape in a stable manner.

  4. Using NIST Crystal Data Within Siemens Software for Four-Circle and SMART CCD Diffractometers

    PubMed Central

    Byram, Susan K.; Campana, Charles F.; Fait, James; Sparks, Robert A.

    1996-01-01

    NIST Crystal Data developed at The National Institute for Standards and Technology has been incorporated with Siemens single crystal software for data collection on four-circle and two-dimensional CCD diffractometers. Why this database is useful in the process of single crystal structure determination, and how the database is searched, are described. Ideas for future access to this and other databases are presented. PMID:27805166

  5. The circle before willis: a historical account of the intracranial anastomosis.

    PubMed

    Lo, William B; Ellis, Harold

    2010-01-01

    The circle of Willis is one of the most famous eponymous structures in human anatomy. There is no doubt Thomas Willis at Oxford accurately demonstrated the anastomotic arterial supply at the base of the brain. However, this eponymous name does not reveal the history of the discovery of the ramification, nor does it give credit to the anatomists and artists who have contributed to the understanding of this clinically important structure. This article first traces the story of the discovery of the circle of Willis. Willis' contribution and innovative approaches are then discussed. Finally, despite Willis' not being the first to describe the circle, we explain why he still deserves to retain the eponymous title. The earlier description of the vasculature at the base of the brain was fixated on a nonexistent structure, at least not in humans, named the rete mirabile. The more scientific study of the blood supply to the brain took place during the Renaissance period, which culminated in the work of Thomas Willis in the 17th century.

  6. 24. VIEW SHOWING CIRCLE CONCRETE PAD AT RADAR SITE, LOOKING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. VIEW SHOWING CIRCLE CONCRETE PAD AT RADAR SITE, LOOKING SOUTH Everett Weinreb, photographer, April 1988 - Los Pinetos Nike Missile Site, Santa Clara Road, Los Angeles National Forest, Sylmar, Los Angeles County, CA

  7. OUTER RIM OF CIRCLE, WITH LIVE OAK TREE AT LEFT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OUTER RIM OF CIRCLE, WITH LIVE OAK TREE AT LEFT FOREGROUND AND CEMETERY SECTION 25 IN BACKGROUND. VIEW TO WEST. - Barrancas National Cemetery, Naval Air Station, 80 Hovey Road, Pensacola, Escambia County, FL

  8. 7. VIEW NORTHWEST, OLD WHITE HORSE PIKE FORM CIRCLE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. VIEW NORTHWEST, OLD WHITE HORSE PIKE FORM CIRCLE - White Horse Pike Rond Point, Intersection of Crescent Boulevard (U.S. Route 130), White Horse Pike (U.S. Route 30), & Clay Avenue, Collingswood, Camden County, NJ

  9. Improving Nursing Management and Practice through Quality Circles.

    ERIC Educational Resources Information Center

    Wine, Julie A.; Baird, John E., Jr.

    1983-01-01

    Nursing managers have tried a number of systems to increase employee participation, and quality circles seem to be the most promising method currently available. Describes effective implementation techniques within a nursing organization. (JOW)

  10. Marathon Oil Company – Circle Ridge NPDES Permit

    EPA Pesticide Factsheets

    Under NPDES permit WY-0000949, the Marathon Oil Company – Circle Ridge is authorized to discharge from its wastewater treatment facility located in Fremont County, Wyoming to a tributary to Coal Draw.

  11. The Euler Line and Nine-Point-Circle Theorems.

    ERIC Educational Resources Information Center

    Eccles, Frank M.

    1999-01-01

    Introduces the Euler line theorem and the nine-point-circle theorem which emphasize transformations and the power of functions in a geometric concept. Presents definitions and proofs of theorems. (ASK)

  12. 1. AERIAL VIEW OF BRIDGE IN CONTEXT INCLUDING VICTORY CIRCLE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. AERIAL VIEW OF BRIDGE IN CONTEXT INCLUDING VICTORY CIRCLE FROM SOUTH. LOOKING NORTH. - Rue Road Bridge, Rue Road, spanning Matchaponix Brook, .35 mile east of intersection with Route 613, Jamesburg, Middlesex County, NJ

  13. Path discrepancies between great circle and rhumb line

    NASA Technical Reports Server (NTRS)

    Kaul, Rajan

    1987-01-01

    A simulation of a mathematical model to compute path discrepancies between great circle and rhumb line flight paths is presented. The model illustrates that the path errors depend on the latitude, the bearing, and the trip length of the flight.

  14. From Quality Circles to Participation: Managing the Transition (Part Two).

    ERIC Educational Resources Information Center

    Simmons, John

    1985-01-01

    This article draws on the experience of such firms as People Express, General Motors, and Digital Equipment Corporation to illustrate successful transition from quality circle participation to full participation in management. (CT)

  15. Low Circle Fatigue Life Model Based on ANFIS

    NASA Astrophysics Data System (ADS)

    Liu, Changhong; Liu, Xintian; Huang, Hu; Zhao, Lihui

    With the adaptive network fuzzy inference system (ANFIS), this paper presents a method of building a model of the low circle fatigue life. According to real experiment data got in the low circle fatigue experiment, a fatigue life model for low fatigue experiment is built. Finally, comparing with the Manson-Coffin equation, it can be concluded that the model of ANFIS is accurately and effectively.

  16. General exact solution of incompressible potential flows around two circles

    NASA Astrophysics Data System (ADS)

    Qianxi, Wang; Lixian, Zhuang; Binggang, Tong

    1993-02-01

    Three exact solutions are obtained for 2-D incompressible potential flows around two moving circles in three cases: (i) expansion (or contraction) of themselves, (ii) approaching (or departing from) each other, (iii) moving perpendicularly to the line connecting the centres in opposite directions. Meanwhile, another set of two exact solutions is obtained for 2-D incompressible potential flows between two moving eccentric circles in two cases: moving parallely or perpendicularly to the line connecting the centres.

  17. Biology coming full circle: joining the whole and the parts.

    PubMed

    Wikswo, John P; Porter, Andrew P

    2015-01-01

    The new cover of Experimental Biology and Medicine features the hermeneutic circle of biology, a concept we have adapted from the hermeneutic principle that one understands the whole only in terms of each part and the parts only in terms of the whole. Our hermeneutic circle summarizes the course of experimental biology through 2500 years of the achievements of reductionist research (understanding the parts), which culminates in our ability to rapidly sequence the genome. Rather than returning along the same path in a constructionist approach that simply builds upon this knowledge, but in reverse, an alternative is to close the circle with synthetic constructions that seek to integrate the full complexity of biological and physiological systems (understanding the whole), of which organs-on-chips are one example. This closing of the circle cannot be a comprehensively accurate representation of biology, but it can be a synthetic one that effectively defines particular biological subsystems. The illustration of the hermeneutic circle of biology is also intended to suggest both the multiple cycles that may be required to reach such a synthesis and the expansion of the circle in an outward spiral as knowledge increases. Our commentary explains the symbolism of the new cover in a philosophical and scientific discussion.

  18. Biology coming full circle: Joining the whole and the parts

    PubMed Central

    Porter, Andrew P

    2015-01-01

    The new cover of Experimental Biology and Medicine features the hermeneutic circle of biology, a concept we have adapted from the hermeneutic principle that one understands the whole only in terms of each part and the parts only in terms of the whole. Our hermeneutic circle summarizes the course of experimental biology through 2500 years of the achievements of reductionist research (understanding the parts), which culminates in our ability to rapidly sequence the genome. Rather than returning along the same path in a constructionist approach that simply builds upon this knowledge, but in reverse, an alternative is to close the circle with synthetic constructions that seek to integrate the full complexity of biological and physiological systems (understanding the whole), of which organs-on-chips are one example. This closing of the circle cannot be a comprehensively accurate representation of biology, but it can be a synthetic one that effectively defines particular biological subsystems. The illustration of the hermeneutic circle of biology is also intended to suggest both the multiple cycles that may be required to reach such a synthesis and the expansion of the circle in an outward spiral as knowledge increases. Our commentary explains the symbolism of the new cover in a philosophical and scientific discussion. PMID:25583953

  19. Endoscopic endonasal transsphenoidal exposure of circle of Willis (CW); can it be applied in vascular neurosurgery in the near future? A cadaveric study of 26 cases.

    PubMed

    Chowdhury, Forhad H; Haque, Mohammod R; Kawsar, Khandkar A; Ara, Shamim; Mohammod, Quazi Deen; Sarker, Mainul H; Goel, Atul H

    2012-01-01

    Endonasal transsphenoidal approaches are getting rapidly popular in removing many midline skullbase lesions from crista galli to foramen magnum. For safe removal of these lesions, familiarity with endoscopic endonasal anatomy of circle of Willis is very important. Furthermore, for safe development of this approach in vascular neurosurgery in the near future, endoscopic endonasal exposure of circle of Willis is a fundamental step. The goals in this study were to dissect the circle of Willis completely through the endoscopic endonasal approach and to become more familiar with the views and skills associated with the technique by using fresh cadaveric specimens. After obtaining ethical clearance, 26 fresh cadaver heads were used without any preparation. Using a neuroendoscope, complete exposure of the circle of Willis was done endonasaly, and various observations including relation of circle of Willis was recorded. Complete exposure of the circle of Willis was made through an endonasal approach in all cases without injuring surrounding structures. Endoscopic endonasal extended transsphenoidal exposure of CW can make the surgeon more efficient in removing midline skullbase lesions with safe handling of different parts of circle of Willis and it may help in development of endonasal endoscopic vascular neurosurgery in the near future.

  20. PyMGC3: Finding stellar streams in the Galactic Halo using a family of Great Circle Cell counts methods

    NASA Astrophysics Data System (ADS)

    Mateu, C.

    2014-11-01

    PyMGC3 is a Python toolkit to apply the Modified Great Circle Cell Counts (mGC3) method to search for tidal streams in the Galactic Halo. The code computes pole count maps using the full mGC3/nGC3/GC3 family of methods. The original GC3 method (Johnston et al., 1996) uses positional information to search for 'great-circle-cell structures'; mGC3 makes use of full 6D data and nGC3 uses positional and proper motion data.

  1. Circles reshaping the RNA world: from waste to treasure.

    PubMed

    Liu, Jing; Liu, Tian; Wang, Xiaman; He, Aili

    2017-03-09

    A new type of RNAs was identified from genes traditionally thought to express messenger or linear ncRNA (noncoding RNA) only. They were subsequently named as circRNAs (circular RNAs) due to the covalently closed structure. Accumulating studies were performed to explore the expression profile of circRNAs in different cell types and diseases, the outcomes totally changed our view of ncRNAs, which was thought to be junk by-products in the process of gene transcription, and enriched our poor understanding of its underlying functions. The expression profile of circRNAs is tissue-specific and alters across various stages of cell differentiation. The biological function of circRNAs is multi-faceted, involving five main features (sponge effect, post-transcriptional regulation, rolling circle translation, circRNA-derived pseudogenes and splicing interference) and varying differently from the locations, binding sites and acting modes of circRNAs. The regulating role of circRNAs is not isolated but through an enormous complicated network involving mRNAs, miRNAs and proteins. Although most of the potential functions still remain unclear, circRNAs have been proved to be ubiquitous and critical in regulating cellular processes and diseases, especially in cancers, from the laboratory to the clinic. Herein, we review circRNAs' classification, biogenesis and metabolism, their well-studied and anticipated functions, the current understanding of the potential implications of circRNAs in tumorigenesis and cancer targeted therapy.

  2. Putting the Unit in Pre-Service Secondary Teachers' Unit Circle

    ERIC Educational Resources Information Center

    Moore, Kevin C.; LaForest, Kevin R.; Kim, Hee Jung

    2016-01-01

    We discuss a teaching experiment that explored two pre-service secondary teachers' meanings for the unit circle. Our analyses suggest that the participants' initial unit circle meanings predominantly consisted of calculational strategies for relating a given circle to what they called "the unit circle." These strategies did not entail…

  3. 77 FR 39651 - Proposed Establishment of Class E Airspace; Circle Town, MT

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-05

    ... County Airport, Circle Town, MT, to accommodate aircraft using new Area Navigation (RNAV) Global... aircraft using new RNAV (GPS) standard instrument approach procedures at Circle Town County Airport. This.... * * * * * ANM MT E5 Circle Town, MT [New] Circle Town County Airport (Lat. 47[deg]25'06'' N., long. 105[deg]33...

  4. Three Concentric Circles: Young Chinese English Learners' Perceptions of Purposeful Audiences

    ERIC Educational Resources Information Center

    Liu, Jack Jinghui

    2015-01-01

    English learners have more access to communicate with different purposeful audiences across the Three Concentric Circles of English (Kachu, 1985): the Inner Circle, the Outer Circle and the Expanding Circle. However, young language learners' purposeful audience as a focus of communication has not been emphasized as much as other linguistic…

  5. Putting the Unit in Pre-Service Secondary Teachers' Unit Circle

    ERIC Educational Resources Information Center

    Moore, Kevin C.; LaForest, Kevin R.; Kim, Hee Jung

    2016-01-01

    We discuss a teaching experiment that explored two pre-service secondary teachers' meanings for the unit circle. Our analyses suggest that the participants' initial unit circle meanings predominantly consisted of calculational strategies for relating a given circle to what they called "the unit circle." These strategies did not entail…

  6. Coal geology of the Northeast Circle area, McCone and Dawson counties, Montana

    USGS Publications Warehouse

    Wincentsen, Herbert

    1979-01-01

    The Northeast Circle area is in central McCone and northern Dawson Counties, northeastern Montana. The area encompasses about 940 square miles and has a maximum relief of greater than 1,000 feet. The lowest point (altitude of less than 2,200 feet) is in the Redwater River Valley in the northern part of the area. The highest point (altitude of less than 3,200 feet) is on the Yellowstone-Missouri divide, located in parts of Tps. 18 and 19 N., Rso 49, 50, and 51E., and T. 20 N., Rs. 52 and 53 E. Surface exposures in most of the area consist of yellowish or light-colored sandy shales of the Tongue River Member of the Paleocene Fort Union Formation. The coal beds in the Northeast Circle area occur in the lower 500 feet of this member and are persistent in the field. The predominant structural features of the area are the northeast end of the Weldon monocline-fault in Tps. 21 and 22 N., R. 47 E., and a small steep depression near Circle in sec. 10, T. 19 N., R. 48 E. Otherwise, the structure of the area is nearly flat. Coal in the Northeast Circle area is composed of six main beds: the S, L1, R, Q, P, and Pust beds, in ascending stratigraphic order. Of these, the S, Pust, and P beds are the thickest. The S bed is more than 20 feet thick in some places, but usually ranges in thickness from 6 to 10 feet. The Pust bed, which is about 430-490 feet above the S bed, is more than 18 feet thick in the upper bench and as much as 9 feet thick in the lower bench. Coal thickness in the P bed varies from 0 to 10.5 feet. The other coal seams in the area are generally less than 5 feet thick. All coals are lignite in rank.

  7. White matter disease and an incomplete circle of Willis.

    PubMed

    Ryan, Daniel James; Byrne, Susan; Dunne, Ruth; Harmon, Mark; Harbison, Joseph

    2015-06-01

    White matter disease occurs as a consequence of small vessel disease; however, hypoperfusion may also play a role. We investigated whether patients with less cerebral vessel anastomosis may develop more white matter disease. Magnetic resonance imaging (1.5t) with intracranial magnetic resonance angiography data was collected on a convenience sample between July 2008 and January 2009. All patients were independently assessed for circle of Willis variants by two researchers and categorized into two groups: those with a complete circle of Willis and those with an incomplete circle of Willis (absent vessels). The complete group was sub-divided into a classical group (entirely normal circle of Willis) and a hypoplastic group (hypoplasia but no absent vessels). White matter disease assessment was conducted for these groups, by two researchers blind to magnetic resonance angiography findings, on all patients over 50 years old. The circle of Willis was characterized in 163 patients, while 90 (>50 years) underwent white matter disease assessment. The kappa inter-rater reliability between both circle of Willis assessors and between both white matter disease assessors was 0.57 and 0.63, respectively. The prevalence of circle of Willis variants strongly correlated with the seminal paper by Riggs and Rupp. Independent of age and gender, those with an incomplete circle of Willis (n = 68) exhibited 58% more white matter disease than those with a complete circle of Willis (n = 22) (white matter disease score 6.52 vs. 4.11, respectively, P = 0.03). Patients with absent anterior vessels exhibited more frontal white matter disease than those with intact anterior vessels (3.7 vs. 1.72, P < 0.001). Patients with absent posterior vessels exhibited more occipital white matter disease than those with intact posterior vessels (2.52 vs. 1.34, P = 0.014). These data suggest that congenital absence of anastomotic capacity correlates with incident white matter disease, thus

  8. Effect of stern hull shape on turning circle of ships

    NASA Astrophysics Data System (ADS)

    Jaswar, Maimun, A.; Wahid, M. A.; Priyanto, A.; Zamani, Pauzi, Saman

    2012-06-01

    Many factors such as: stern hull shape, length, draught, trim, propulsion system and external forces affecting the drift angle influence rate of turn and size of turning circle of ships. This paper discusses turning circle characteristics of U and V stern hull shape of Very Large Crude Oil Carrier (VLCC) ships. The ships have same principal dimension such as length, beam, and draught. The turning circle characteristics of the VLCC ships are simulated at 35 degree of rudder angle. In the analysis, firstly, turning circle performance of U-type VLCC ship is simulated. In the simulation, initial ship speed is determined using given power and rpm. Hydrodynamic derivatives coefficients are determined by including effect of fullness of aft run. Using the obtained, speed and hydrodynamic coefficients, force and moment acting on hull, force and moment induced by propeller, force and moment induced by rudder are determined. Finally, ship trajectory, ratio of speed, yaw angle and drift angle are determined. Results of simulation results of the VLCC ship are compared with the experimental one as validation. Using the same method, V-type VLCC is simulated and the simulation results are compared with U-type VLCC ship. Results shows the turning circle of U-type is larger than V-type due to effect stern hul results of simulation are.

  9. An efficient circle detector not relying on edge detection

    NASA Astrophysics Data System (ADS)

    Cai, Jia; Huang, Panfeng; Chen, Lu; Zhang, Bin

    2016-06-01

    Accurate and efficient detection of circular modules fixed on non-cooperative target is a key technology for Tethered Space Robot. This paper presents an efficient circle detector based on region-growing of gradient and histogram distribution of Euclidean distance. Region-growing of gradient is applied to generate arc support regions from single point. And the corresponding square fitting areas are defined to accelerate the detection and decrease storage. A histogram is then used to count frequency of the distances that participates in the accumulator and the parameters of each circle are acquired. Finally, a verification strategy of circular integrity is designed to test the detection results. We have tested our algorithm on 35 images dealing with kinds of circles and ellipses. Experimental results demonstrate that our method is able to detect circular objects under occlusion, image noises and moderate shape deformations with a good precision.

  10. The Circle of Apollonius and Its Applications in Introductory Physics

    NASA Astrophysics Data System (ADS)

    Partensky, Michael B.

    2008-02-01

    The circle of Apollonius is named after the ancient geometrician Apollonius of Perga. This beautiful geometric construct can be helpful when solving some general problems of geometry and mathematical physics, optics, and electricity. Here we discuss two of its applications: localizing an object in space and calculating electric fields. First, we pose an entertaining localization problem to trigger students' interest in the subject. Analyzing this problem, we introduce the circle of Apollonius and show that this geometric technique helps solve the problem in an elegant and intuitive manner. Then we switch to seemingly unrelated problems of calculating the electric fields. We show that the zero equipotential line for two unlike charges is the Apollonius circle for these two charges and use this discovery to find the electric field of a charge positioned near a grounded conductive sphere. Finally, we pose some questions for further examination.

  11. Analysis of the symmetric configuration of the circle of Willis in a series of autopsied corpses.

    PubMed

    Stojanović, Nebojga; Stefanović, Ivica; Kostić, Aleksandar; Radisavejević, Misa; Stojanov, Dragan; Petrović, Sladjana

    2015-04-01

    The forming of the blood vessels network configuration at the base of the brain and interconnecting of blood vessels during the embryogenesis is directly related to the phylogenetic development of the brain and brain structures. A blood vessel configuration at the brain base, in the form of a ring or a hexagon, stands in direct relation to the perfusion needs of certain parts of the brain during its primary differentiation. The aim of this paper was to determine the incidence of certain blood vessel configurations at the base of the brain and understanding their symmetry or asymmetry. Analysis of the blood vessels at the base of the brain was performed on the autopsied subjects. The object of observation was the anterior segment of the circle of Willis consisting of C1- a. carotis interna (ICA), above a. communicaus posterior (PcoA), the segment A1 a. cerebri anterior (ACA) from a. carotis interna bifurcation to the a. communicans anterior (AcoA) and a communicans anterior itself, as well as the posterior segment consisting of PcoA and the segment P1--a. cerebri posterior (PCA) from the a. basilaris bifurcation to the PcoA. For the purpose of grouping the findings, the four basic configuration types of the circle of Willis were identified based on its symmetry or asymmetry. Type-A (symmetric circle of Willis), type-B (asymmetric circle of Willis' due to the unilateral hypoplastic A1-ACA); type-C (symmetric circle of Willis with bilateral symmetric changes on PcoA) and type-D (asymmetric circle of Willis due to the asymmetric changes on PcoA). Autosy was performed on 56 corpses. A total of 41 (73.2%) subjects were recorded with a symmetric configuration of the circle of Willis', of which 27 (48.2%) subjects had type A and 14 (25%) type C. The asymmetric configuration was present in 15 (26.8%) subjects, of whom 9 (16%) had type B and 6 (10.8%) subjects, of whom 9 (16%) had type B and 6 (10.8%) type D. The symmetric Willis group (73.2%) did not have a homogeneous

  12. The role of Willis circle variations during unilateral selective cerebral perfusion: a study of 500 circles.

    PubMed

    Papantchev, Vassil; Stoinova, Vesela; Aleksandrov, Alexander; Todorova-Papantcheva, Daniela; Hristov, Stanislav; Petkov, Dimitar; Nachev, Gencho; Ovtscharoff, Wladimir

    2013-10-01

    During unilateral selective cerebral perfusion (uSCP), with right axillary artery or brachiocephalic trunk cannulation, the brain receives blood only via the right common carotid artery and right vertebral artery (VA). The left hemisphere is perfused mainly through the circle of Willis (CW). However, at least 50% of individuals have some variation in the CW. The aim of the present work was to study the variations in CW and VA that could have an impact on haemodynamics during uSCP. From May 2005 to March 2012, a total number of 250 circles obtained via routine dissection for medico-legal reasons were examined. The external diameters of all CW segments and both VAs were measured. From January 2008 to March 2012, a total number of 250 patients subjected to computed tomographic angiography of the CW were also examined. Nine evident configurations of the CW that could cause hypoperfusion during uSCP were observed. They were subdivided in to seven types, according to location and the number of major vessels at risk of hypoperfusion. Type IA: hypo/aplasia of left posterior communicating artery (PComA), found in 35.6% of cases; Type IB: hypo/aplasia of anterior communicating artery (AComA), found in 2% of cases; Type IIA: hypo/aplasia of both left PComA and AComA, found in 4.8% of cases; Type IIB: hypo/aplasia of precommunicating (P1) segment of left posterior cerebral artery or right VA, found in 9.2% of cases; Type IIIA: hypo/aplasia of precommunicating (A1) segment of right anterior cerebral artery, found in 6% of cases; Type IIIB: hypo/aplasia of both right VA and AComA, found in 0.2% of cases; Type IV: hypo/aplasia of both right A1 and right VA or both right A1 and left P1, found in 0.8% of cases. All types were present in 58.6% of all examined CWs. Our results show that CW variations are present in a significant number of patients. Our data support the need for extensive preoperative examination and meticulous intraoperative monitoring of cerebral perfusion during u

  13. Easing The Calculation Of Bolt-Circle Coordinates

    NASA Technical Reports Server (NTRS)

    Burley, Richard K.

    1995-01-01

    Bolt Circle Calculation (BOLT-CALC) computer program used to reduce significant time consumed in manually computing trigonometry of rectangular Cartesian coordinates of holes in bolt circle as shown on blueprint or drawing. Eliminates risk of computational errors, particularly in cases involving many holes or in cases in which coordinates expressed to many significant digits. Program assists in many practical situations arising in machine shops. Written in BASIC. Also successfully compiled and implemented by use of Microsoft's QuickBasic v4.0.

  14. Marrying Heterogeneous Circles of Trust: No Silver Bullet Yet

    NASA Astrophysics Data System (ADS)

    Ates, Mikaël; Gravier, Christophe; Fayolle, Jacques; Sauviac, Bruno

    2008-11-01

    Numerous business and state-owned entities assert the need of secured information exchanges on digital identities based on trusted third parties. Entities trusting each other create a federation. At first, it is necessary for them to formalize this alliance with legal documents. In a second time, an architecture of identity federation will allow them to establish technical trust links, creating a circle of trust, most often with a public key infrastructure. The real challenge for the identity federation domain is the interoperability of information systems thanks to normalized and standardized protocols, that is to say, realize interconnection of circles of trust.

  15. Iterative-decreasing calibration method based on regional circle

    NASA Astrophysics Data System (ADS)

    Zhao, Hongyang

    2017-07-01

    In the field of computer vision, camera calibration is a hot issue. For the existing coupled problem of calculating distortion center and the distortion factor in the process of camera calibration, this paper presents an iterative-decreasing calibration method based on regional circle, uses the local area of the circle plate to calculate the distortion center coordinates by iterative declining, and then uses the distortion center to calculate the local area calibration factors. Finally, makes distortion center and the distortion factor for the global optimization. The calibration results show that the proposed method has high calibration accuracy.

  16. Interaction of circling relativistic charges and interference in their radiation

    NASA Astrophysics Data System (ADS)

    Gordeyev, A. N.

    1997-11-01

    The radiation emitted by two charges circling at opposite ends of a diameter at arbitrary uniform speed is considered, with special attention being paid to interference effects. The difference in the rate of radiation from the system and the sum of the powers emitted separately by each circling charge is shown to be equal to the work done by the particles on each other through their exact Liénard-Wiechert fields, in accordance with the Poynting theorem. Some peculiarities of the radiation at high and low speeds are noted and explained.

  17. A Phase Transition for Circle Maps and Cherry Flows

    NASA Astrophysics Data System (ADS)

    Palmisano, Liviana

    2013-07-01

    We study C 2 weakly order preserving circle maps with a flat interval. The main result of the paper is about a sharp transition from degenerate geometry to bounded geometry depending on the degree of the singularities at the boundary of the flat interval. We prove that the non-wandering set has zero Hausdorff dimension in the case of degenerate geometry and it has Hausdorff dimension strictly greater than zero in the case of bounded geometry. Our results about circle maps allow to establish a sharp phase transition in the dynamics of Cherry flows.

  18. Organometallic chemistry: Fused ferrocenes come full circle

    NASA Astrophysics Data System (ADS)

    Musgrave, Rebecca A.; Manners, Ian

    2016-09-01

    Chemists have long been fascinated by electron delocalization, from both a fundamental and applied perspective. Macrocyclic oligomers containing fused ferrocenes provide a new structural framework -- containing strongly interacting metal centres -- that is capable of supporting substantial charge delocalization.

  19. Toroidal Single Wall Carbon Nanotubes in Fullerene Crop Circles

    NASA Technical Reports Server (NTRS)

    Han, Jie; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    We investigate energetics and structure of circular and polygonal single wall carbon nanotubes (SWNTs) using large scale molecular simulations on NAS SP2, motivated by their unusual electronic and magnetic properties. The circular tori are formed by bending tube (no net whereas the polygonal tori are constructed by turning the joint of two tubes of (n, n), (n+1, n-1) and (n+2, n-2) with topological pentagon-heptagon defect, in which n =5, 8 and 10. The strain energy of circular tori relative to straight tube decreases by I/D(sup 2) where D is torus diameter. As D increases, these tori change from buckling to an energetically stable state. The stable tori are perfect circular in both toroidal and tubular geometry with strain less than 0. 03 eV/atom when D greater than 10, 20 and 40 nm for torus (5,5), (8,8) and (10, 10). Polygonal tori, whose strain is proportional to the number of defects and I/D are energetically stable even for D less than 10 nm. However, their strain is higher than that of perfect circular tori. In addition, the local maximum strain of polygonal tori is much higher than that of perfect circular tori. It is approx. 0.03 eV/atom or less for perfect circular torus (5,5), but 0.13 and 0.21 eV/atom for polygonal tori (6,4)/(5,5) and (7,3)/(5,5). Therefore, we conclude that the circular tori with no topological defects are more energetically stable and kinetically accessible than the polygonal tori containing the pentagon-heptagon defects for the laser-grown SWNTs and Fullerene crop circles.

  20. Production of dumbbell probe through hairpin cleavage-ligation and increasing RCA sensitivity and specificity by circle to circle amplification

    PubMed Central

    Wei, Hua; Tang, Suming; Hu, Tianyu; Zhao, Guojie; Guan, Yifu

    2016-01-01

    Dumbbell probe (DP) attracts increasing interests in rolling circle amplification (RCA). A universal DP production method through cleavage-ligation of hairpin was proposed and optimized. The production is characterized by restriction endonuclease (RE)-induced cleavage ends ligation. It has the advantage of phosphorylation-free, splint-free and purification-free. To optimize designing, we found that the position of RE cleavage sequence in the stem and the primer position in the loop affected the formation and amplification of DP obviously. Both sticky and blunt ends cleaved by RE produce DP efficiently. Moreover, we introduced this DP into circle to circle (C2C) RCA based on the same cleavage-ligation principle, and acquired high sensitivity. By combining a two-ligation design and the C2C strategy, specificity for detecting let-7 family members was increased extremely. Furthermore, coreaction of different steps facilitated convenient formation and amplification process of DP. PMID:27385060

  1. Production of dumbbell probe through hairpin cleavage-ligation and increasing RCA sensitivity and specificity by circle to circle amplification.

    PubMed

    Wei, Hua; Tang, Suming; Hu, Tianyu; Zhao, Guojie; Guan, Yifu

    2016-07-07

    Dumbbell probe (DP) attracts increasing interests in rolling circle amplification (RCA). A universal DP production method through cleavage-ligation of hairpin was proposed and optimized. The production is characterized by restriction endonuclease (RE)-induced cleavage ends ligation. It has the advantage of phosphorylation-free, splint-free and purification-free. To optimize designing, we found that the position of RE cleavage sequence in the stem and the primer position in the loop affected the formation and amplification of DP obviously. Both sticky and blunt ends cleaved by RE produce DP efficiently. Moreover, we introduced this DP into circle to circle (C2C) RCA based on the same cleavage-ligation principle, and acquired high sensitivity. By combining a two-ligation design and the C2C strategy, specificity for detecting let-7 family members was increased extremely. Furthermore, coreaction of different steps facilitated convenient formation and amplification process of DP.

  2. Culture Circles: A Cultural Self-Awareness Exercise.

    ERIC Educational Resources Information Center

    Coombs, Gary; Sarason, Yolanda

    1998-01-01

    The Culture Circles exercise involves pairs of students in describing their cultural background, customs, and role models and then describing these things from the point of view of a different cultural background. Debriefing discussions examine what is culture, whether people choose their identity, and the discomfort of difference. (SK)

  3. The 2004 Presidential Election and Young Voters. CIRCLE Fact Sheet.

    ERIC Educational Resources Information Center

    Center for Information and Research on Civic Learning and Engagement, 2004

    2004-01-01

    Young people?s interest in the 2004 presidential election is at its highest since 1992. According to a September MTV/The Center for Information & Research on Civic Learning & Engagement (CIRCLE) poll conducted by CBS News, 81 percent of young registered voters are paying close attention to the campaign, compared to 85 percent in 1992, the last…

  4. Maximum-likelihood estimation of circle parameters via convolution.

    PubMed

    Zelniker, Emanuel E; Clarkson, I Vaughan L

    2006-04-01

    The accurate fitting of a circle to noisy measurements of circumferential points is a much studied problem in the literature. In this paper, we present an interpretation of the maximum-likelihood estimator (MLE) and the Delogne-Kåsa estimator (DKE) for circle-center and radius estimation in terms of convolution on an image which is ideal in a certain sense. We use our convolution-based MLE approach to find good estimates for the parameters of a circle in digital images. In digital images, it is then possible to treat these estimates as preliminary estimates into various other numerical techniques which further refine them to achieve subpixel accuracy. We also investigate the relationship between the convolution of an ideal image with a "phase-coded kernel" (PCK) and the MLE. This is related to the "phase-coded annulus" which was introduced by Atherton and Kerbyson who proposed it as one of a number of new convolution kernels for estimating circle center and radius. We show that the PCK is an approximate MLE (AMLE). We compare our AMLE method to the MLE and the DKE as well as the Cramér-Rao Lower Bound in ideal images and in both real and synthetic digital images.

  5. Circle Time for Social and Emotional Learning in Primary School

    ERIC Educational Resources Information Center

    Cefai, Carmel; Ferrario, Erika; Cavioni, Valeria; Carter, Audrey; Grech, Tracy

    2014-01-01

    This paper discusses the findings and implications of a semi-randomised control trial study on the effectiveness of circle time (CT) on primary school students' social and emotional learning, as well as classroom teachers' and students' experience of CT. A social and emotional learning programme was delivered through CT by trained classroom…

  6. Intersections of a Circle and a Square: An Investigation

    ERIC Educational Resources Information Center

    Canada, Dan; Blair, Stephen

    2007-01-01

    The investigation of how a circle and square lying in the same plane could intersect each other is an excellent example of geometric problem-solving. This paper explores three facets of the investigation: (1) finding out how many points of intersection are possible, (2) classifying the different ways of intersection, and (3) determining which ways…

  7. NCSALL Study Circle Guide: Teaching and Learning in Authentic Contexts

    ERIC Educational Resources Information Center

    National Center for the Study of Adult Learning and Literacy (NCSALL), 2003

    2003-01-01

    This Study Circle is based on research conducted by a team led by Victoria Purcell-Gates. Their research examines the relationships between two dimensions of literacy instruction (the degree of authenticity of activities and texts and the degree of student/teacher collaboration) and changes in the literacy practices of students outside the…

  8. First Nations Education in Canada: The Circle Unfolds.

    ERIC Educational Resources Information Center

    Battiste, Marie, Ed.; Barman, Jean, Ed.

    This collection of 15 writings by Aboriginal and non-Aboriginal educators examines the issues and dilemmas of First Nations education in Canada 25 years after the beginnings of First Nations control of education. Organized around the concept of the Sacred Circle, the essays are grouped into four sections: reconceptualizing First Nations education,…

  9. Critical Friendship Circles: The Cultural Challenge of Cool Feedback

    ERIC Educational Resources Information Center

    Wachob, Phyllis

    2011-01-01

    A critical friend is a friend who offers critique on practice. Critical Friendship Circles (CFCs) are groups of critical friends who meet for feedback using a protocol. A study with 95 participants at an American university in Egypt has revealed challenges specific to the culture of most "Teaching English as a Foreign Language"…

  10. Literature Circles: A Perfect Match for Online Instruction

    ERIC Educational Resources Information Center

    Whittingham, Jeff

    2013-01-01

    This article describes the author's search for an appropriate and satisfying online teaching method. After experimenting with several methods (chat room, discussion board, student led discussion), the author reached back to his face-to-face classroom success with literature circles. This article reports the results of research conducted by the…

  11. Pre-Service Teachers' Concept Image for Circle and Ellipse

    ERIC Educational Resources Information Center

    Wright, Vince

    2013-01-01

    Concept image is proposed by Vinner and Tall (1981) to differentiate the elements and relationships that a learner constructs about a concept from formal mathematical definition for the same concept. The answers of 119 University students to an examination question are analysed to establish the concept images they have for circle and ellipse. The…

  12. First Voice: The Circle of Courage and Independent Living

    ERIC Educational Resources Information Center

    Reid, Jennifer S.; Ross, Jean W.

    2005-01-01

    Adolescents in foster care must have a voice and play an active role in envisioning and planning for successful adulthood. This principle serves as the philosophy of First Voice, a training package for anyone who works with youth in foster care. The philosophy corresponds with the four parts of the Circle of Courage--Independence, Belonging,…

  13. Transversality in scalar reaction-diffusion equations on a circle

    NASA Astrophysics Data System (ADS)

    Czaja, Radoslaw; Rocha, Carlos

    We prove that stable and unstable manifolds of hyperbolic periodic orbits for general scalar reaction-diffusion equations on a circle always intersect transversally. The argument also shows that for a periodic orbit there are no homoclinic connections. The main tool used in the proofs is Matano's zero number theory dealing with the Sturm nodal properties of the solutions.

  14. First Nations Education in Canada: The Circle Unfolds.

    ERIC Educational Resources Information Center

    Battiste, Marie, Ed.; Barman, Jean, Ed.

    This collection of 15 writings by Aboriginal and non-Aboriginal educators examines the issues and dilemmas of First Nations education in Canada 25 years after the beginnings of First Nations control of education. Organized around the concept of the Sacred Circle, the essays are grouped into four sections: reconceptualizing First Nations education,…

  15. Full Circle: A New Look at Multiage Education.

    ERIC Educational Resources Information Center

    Chase, Penelle; Doan, Jane

    Noting that there is a great demand for information to help educators learn about and develop programs in multiage education, this book shares many ideas on multiage instruction. The 12 chapters of the book are: (1) "Circling Back" (Jane Doan), on the resurgence of interest in the multiage movement; (2) "One Day" (Penelle Chase), exploring a day…

  16. Literature Circles: A Perfect Match for Online Instruction

    ERIC Educational Resources Information Center

    Whittingham, Jeff

    2013-01-01

    This article describes the author's search for an appropriate and satisfying online teaching method. After experimenting with several methods (chat room, discussion board, student led discussion), the author reached back to his face-to-face classroom success with literature circles. This article reports the results of research conducted by the…

  17. Revisiting Cyberbullying in Schools Using the Quality Circle Approach

    ERIC Educational Resources Information Center

    Paul, Simone; Smith, Peter K.; Blumberg, Herbert H.

    2012-01-01

    An earlier study reported the use of Quality Circles (QC) in a UK school in the context of understanding and reducing bullying and cyberbullying. Here, we report further work in the same school setting. The QC approach allows explorative analysis of problems in school settings, whereby students embark on a problem-solving exercise over a period of…

  18. Full Circle: A New Look at Multiage Education.

    ERIC Educational Resources Information Center

    Chase, Penelle; Doan, Jane

    Noting that there is a great demand for information to help educators learn about and develop programs in multiage education, this book shares many ideas on multiage instruction. The 12 chapters of the book are: (1) "Circling Back" (Jane Doan), on the resurgence of interest in the multiage movement; (2) "One Day" (Penelle Chase), exploring a day…

  19. The Characterizations of Triangles Using the Nine-Point Circles

    ERIC Educational Resources Information Center

    Srinivasan, V. K.

    2012-01-01

    In this note, primarily intended for high school students and high school teachers, characterizations of a right triangle and an equilateral triangle in the Euclidean plane are presented using the nine-point circle of a given triangle. Geometrical applications are explored along with their possible uses in the teaching environment. (Contains 4…

  20. Defining Leadership: Collegiate Women's Learning Circles: A Qualitative Approach

    ERIC Educational Resources Information Center

    Preston-Cunningham, Tammie; Elbert, Chanda D.; Dooley, Kim E.

    2017-01-01

    The researchers employed qualitative methods to evaluate first-year female students' definition of "leadership" through involvement in the Women's Learning Circle. The findings revealed that students defined leadership in two dimensions: traits and behaviors. The qualitative findings explore a multidimensional approach to the voices of…

  1. Sacred Circles: 2000 Years of North American Indian Art

    ERIC Educational Resources Information Center

    Journal of American Indian Education, 1977

    1977-01-01

    "Sacred Circles" opened April 16, 1977 at the Nelson Gallery of Art-Atkins Museum of Fine Arts in Kansas City for its only showing in the Americas; the 850 objects on loan from 90 museums and private collectors included the "Adena Pipe" (considered the most important archaeological object found in the eastern US). (JC)

  2. Professionalization in Youth Work? Opening and Deepening Circles of Inquiry

    ERIC Educational Resources Information Center

    Fusco, Dana; Baizerman, Michael

    2013-01-01

    In this article, the authors examine the claims of professionalization in youth work as both a process and outcome that aims to ultimately improve the lives of young people. The topic of professionalization is then approached through three circles of inquiry that reframe the issue(s) through the historical and sociocultural situatedness of…

  3. Modeling of human circle of Willis with and without aneurisms.

    PubMed

    Ivanov, Dmitry; Dol, Alexander; Pavlova, Olga; Aristambekova, Asel

    2014-01-01

    This paper includes results of the first stage of research aimed at the development of recommendations for physicians in order to help them to choose a particular type of cerebral arteries aneurysms treatment. Recent studies show that the majority of aneurysms develop as a result of hemodynamic and degenerative lesions of the vascular wall. Obviously, such wall damage can be studied using the methods of continuum mechanics and numerical simulations. Biomechanical modelling allows us to study hemodynamic parameters and stress-strain state of these arteries in health and disease, and to formulate practical recommendations for the necessity and reasonable selection of a particular type of cerebral arteries aneurysm treatment. At this stage the realistic geometric models of arterial circle of Willis were built for its normal state and in the presence of aneurysms. The ultrasound analysis of circle of Willis was conducted in order to obtain blood flow parameters and the boundary conditions for carotid and vertebral arteries. Also, the mechanical properties of these arteries were investigated and constants of the Mooney-Rivlin strain energy function were obtained. Thus, the boundary problem describing the behaviour of human Willis circle arteries was stated. Further, this problem will be solved numerically using the finite element method. The numerical results will be analyzed from the point of view of the influence of the mechanical factors on the emergence, growth and rupture of circle of Willis aneurysms.

  4. Sacred Circles: 2000 Years of North American Indian Art

    ERIC Educational Resources Information Center

    Journal of American Indian Education, 1977

    1977-01-01

    "Sacred Circles" opened April 16, 1977 at the Nelson Gallery of Art-Atkins Museum of Fine Arts in Kansas City for its only showing in the Americas; the 850 objects on loan from 90 museums and private collectors included the "Adena Pipe" (considered the most important archaeological object found in the eastern US). (JC)

  5. The magic of fairy circles: Built or created?

    NASA Astrophysics Data System (ADS)

    Sahagian, Dork

    2017-05-01

    Fairy circles are rings of relatively dense grass in arid regions with sparse vegetation. The most famous examples are found in the Namib Desert. There has been an ongoing debate regarding the origin of these features, and a recent paper by Ravi et al. (2017, doi:10.1002/2016JG003604) sheds some light on this situation.

  6. United States Participation in the Pacific Circle Consortium. Final Report.

    ERIC Educational Resources Information Center

    Northwest Regional Educational Lab., Portland, OR.

    The goal of the Pacific Circle Project is to improve international and intercultural understanding among the people and nations of the Pacific. Consortium member countries are Australia, Canada, New Zealand, and the United States. Within the countries are chosen member institutions. Two major types of activities of the consortium are the exchange…

  7. School of Urban Wilderness Survival and the Circle of Courage

    ERIC Educational Resources Information Center

    Marlowe, Jay M.; Pearl, Nick L.; Marlowe, Mike J.

    2009-01-01

    Brendtro, Brokenleg, and Van Bockern (2002) describe the Circle of Courage model for creating environments in which all children can thrive. This approach blends youth developmental research, the wisdom of pioneer workers, and Native American philosophies of child care. This model for reclaiming youth at risk posits four elements as essential for…

  8. Outcomes and Accomplishments of The Circles of Care Planing Efforts

    ERIC Educational Resources Information Center

    Duclos, Christine W.; Phillips, Mary; LeMaster, Pamela L.

    2004-01-01

    This paper presents outcomes and accomplishments of the first round of participating individuals, communities, and grantees of the Circles of Care program (CoC). While accomplishing all CoC program goals, the initiative supported grantees in developing individual service delivery system models and positioned each grantee advantageously for…

  9. Hoop Dancing: Literature Circles and Native American Storytelling.

    ERIC Educational Resources Information Center

    Bruce, Heather E.

    2003-01-01

    Considers how misrepresentations of Indian culture can be addressed through the study of Native American oral traditions and literatures. Details the use of literature circles and storytelling in the classroom to combat negative stereotypes and racism. Discusses ways of weaving interpretive threads, examining misconceptions, reading and writing…

  10. The Misuse of the Circle Notation to Represent Aromatic Rings.

    ERIC Educational Resources Information Center

    Belloli, Robert C.

    1983-01-01

    Discusses the confusion and erroneous conclusions that can result from the overuse and misuse of the circle notation to represent aromaticity in polycylic aromatic hydrocarbons. Includes nature of the problem, textbook treatment, and a possible compromise method of representation. (Author/JN)

  11. The Quality Control Circle: Is It for Education?

    ERIC Educational Resources Information Center

    Land, Arthur J.

    From its start in Japan after World War II, the Quality Control Circle (Q.C.) approach to management and organizational operation evolved into what it is today: people doing similar work meeting regularly to identify, objectively analyze, and develop solutions to problems. The Q.C. approach meets Maslow's theory of motivation by inviting…

  12. School of Urban Wilderness Survival and the Circle of Courage

    ERIC Educational Resources Information Center

    Marlowe, Jay M.; Pearl, Nick L.; Marlowe, Mike J.

    2009-01-01

    Brendtro, Brokenleg, and Van Bockern (2002) describe the Circle of Courage model for creating environments in which all children can thrive. This approach blends youth developmental research, the wisdom of pioneer workers, and Native American philosophies of child care. This model for reclaiming youth at risk posits four elements as essential for…

  13. First Voice: The Circle of Courage and Independent Living

    ERIC Educational Resources Information Center

    Reid, Jennifer S.; Ross, Jean W.

    2005-01-01

    Adolescents in foster care must have a voice and play an active role in envisioning and planning for successful adulthood. This principle serves as the philosophy of First Voice, a training package for anyone who works with youth in foster care. The philosophy corresponds with the four parts of the Circle of Courage--Independence, Belonging,…

  14. Examining Circle of Security™: A Review of Research and Theory

    ERIC Educational Resources Information Center

    Mercer, Jean

    2015-01-01

    The Circle of Security™ interventions are psychosocial treatments intended to increase maternal sensitivity and thus child attachment security in infants and young children. A small number of publications have reported empirical research on outcomes of these treatments. This article reviews the research evidence, plausibility, theoretical…

  15. The Circle of Apollonius and Its Applications in Introductory Physics

    ERIC Educational Resources Information Center

    Partensky, Michael B.

    2008-01-01

    The circle of Apollonius is named after the ancient geometrician Apollonius of Perga. This beautiful geometric construct can be helpful when solving some general problems of geometry and mathematical physics, optics, and electricity. Here we discuss two of its applications: localizing an object in space and calculating electric fields. First, we…

  16. Examining Circle of Security™: A Review of Research and Theory

    ERIC Educational Resources Information Center

    Mercer, Jean

    2015-01-01

    The Circle of Security™ interventions are psychosocial treatments intended to increase maternal sensitivity and thus child attachment security in infants and young children. A small number of publications have reported empirical research on outcomes of these treatments. This article reviews the research evidence, plausibility, theoretical…

  17. VIEW OF PIEDMONT AVENUE TRAFFIC CIRCLE AT INTERSECTION OF CHANNING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF PIEDMONT AVENUE TRAFFIC CIRCLE AT INTERSECTION OF CHANNING WAY. SEEN FROM NE CORNER LOOKING SW. Photograph by Fredrica Drotos and Michael Kelly, July 9, 2006 - Piedmont Way & the Berkeley Property Tract, East of College Avenue between Dwight Way & U.C. Memorial Stadium, Berkeley, Alameda County, CA

  18. VIEW OF PIEDMONT AVENUE TRAFFIC CIRCLE AT INTERSECTION OF CHANNING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF PIEDMONT AVENUE TRAFFIC CIRCLE AT INTERSECTION OF CHANNING WAY VIEW OF 2401 PIEDMONT, ALPHA EPSILON PHI HOUSE BY RATCLIFF & RATCLIFF, 1958. SEEN FROM NW CORNER LOOKING SE. Photograph by Brian Grogan, July 8, 2007 - Piedmont Way & the Berkeley Property Tract, East of College Avenue between Dwight Way & U.C. Memorial Stadium, Berkeley, Alameda County, CA

  19. Circle Time for Social and Emotional Learning in Primary School

    ERIC Educational Resources Information Center

    Cefai, Carmel; Ferrario, Erika; Cavioni, Valeria; Carter, Audrey; Grech, Tracy

    2014-01-01

    This paper discusses the findings and implications of a semi-randomised control trial study on the effectiveness of circle time (CT) on primary school students' social and emotional learning, as well as classroom teachers' and students' experience of CT. A social and emotional learning programme was delivered through CT by trained classroom…

  20. The Study Circle--For Learning and Democracy

    ERIC Educational Resources Information Center

    Bjerkaker, Sturla

    2006-01-01

    The study circle is described as a democratic and emancipatory method for learning that can be summarized in three words: learning by sharing. This method offers opportunities and possibilities for all participants to contribute their previous knowledge and experiences through open and democratic dialogue. As a method for "liberal adult…

  1. Intersections of a Circle and a Square: An Investigation

    ERIC Educational Resources Information Center

    Canada, Dan; Blair, Stephen

    2007-01-01

    The investigation of how a circle and square lying in the same plane could intersect each other is an excellent example of geometric problem-solving. This paper explores three facets of the investigation: (1) finding out how many points of intersection are possible, (2) classifying the different ways of intersection, and (3) determining which ways…

  2. Defining Leadership: Collegiate Women's Learning Circles: A Qualitative Approach

    ERIC Educational Resources Information Center

    Preston-Cunningham, Tammie; Elbert, Chanda D.; Dooley, Kim E.

    2017-01-01

    The researchers employed qualitative methods to evaluate first-year female students' definition of "leadership" through involvement in the Women's Learning Circle. The findings revealed that students defined leadership in two dimensions: traits and behaviors. The qualitative findings explore a multidimensional approach to the voices of…

  3. The Governance of Australia. Civics and Citizenship Learning Circle Kit.

    ERIC Educational Resources Information Center

    Gow, Neil

    This kit, the first of four learning circles on civics and citizenship, addresses a series of broad issues about the way in which Australia is governed. Introductory materials include a synopsis of the six sessions; lists of 51 references, 29 Internet sites, and 13 videos and CDs; glossary; and list of 19 resource materials. Session guides are…

  4. Critical Friendship Circles: The Cultural Challenge of Cool Feedback

    ERIC Educational Resources Information Center

    Wachob, Phyllis

    2011-01-01

    A critical friend is a friend who offers critique on practice. Critical Friendship Circles (CFCs) are groups of critical friends who meet for feedback using a protocol. A study with 95 participants at an American university in Egypt has revealed challenges specific to the culture of most "Teaching English as a Foreign Language"…

  5. The Misuse of the Circle Notation to Represent Aromatic Rings.

    ERIC Educational Resources Information Center

    Belloli, Robert C.

    1983-01-01

    Discusses the confusion and erroneous conclusions that can result from the overuse and misuse of the circle notation to represent aromaticity in polycylic aromatic hydrocarbons. Includes nature of the problem, textbook treatment, and a possible compromise method of representation. (Author/JN)

  6. Inclusive Teaching Circles: Mechanisms for Creating Welcoming Classrooms

    ERIC Educational Resources Information Center

    Moore, Sharon; Wallace, Sherri L.; Schack, Gina; Thomas, M. Shelley; Lewis, Linda; Wilson, Linda; Miller, Shawnise; D'Antoni, Joan

    2010-01-01

    This essay examines the Inclusive Teaching Circle (ITC) as a mechanism for faculty development in creating instructional tools that embrace an inclusive pedagogy reflecting diversity, cultural competence and social justice. We describe one group's year-long participation in an ITC at a large, metropolitan research university in the south. Next, we…

  7. Problem Posing and Problem Solving in a Math Teacher's Circle

    ERIC Educational Resources Information Center

    Appleton, Eric; Farina, Solange; Holzer, Tyler; Kotelawala, Usha; Trushkowsky, Mark

    2017-01-01

    This article describes the New York City Community of Adult Math Instructors (CAMI), a math teachers' circle founded in November 2014. The authors share details about their own participation in CAMI to show the professional growth that research-based, peer-led professional development can offer for adult educators.

  8. VIEW OF PIEDMONT AVENUE TRAFFIC CIRCLE AT INTERSECTION OF CHANNING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF PIEDMONT AVENUE TRAFFIC CIRCLE AT INTERSECTION OF CHANNING WAY. SEEN FROM SW CORNER TOWARDS 2395 PIEDMONT, SIGMA PI HOUSE BY FREDERICK H. REIMERS, 1928. LOOKING NORTH. Photograph by Brian Grogan, July 8, 2007 - Piedmont Way & the Berkeley Property Tract, East of College Avenue between Dwight Way & U.C. Memorial Stadium, Berkeley, Alameda County, CA

  9. Using Literature Circles to Discuss Social Justice in Teacher Education

    ERIC Educational Resources Information Center

    Madhuri, Marga; Walker, Nancy; Landmann-Johnsey, Erica; Laughter, Judson

    2015-01-01

    Literacy educators feel it is incumbent on teacher preparation programs to prepare teacher candidates with the dispositions and competencies needed to work with students from diverse racial, cultural, and economic backgrounds. As a way to initiate the discussion and help candidates examine their own views on race, literature circles are used. The…

  10. The Circle of Apollonius and Its Applications in Introductory Physics

    ERIC Educational Resources Information Center

    Partensky, Michael B.

    2008-01-01

    The circle of Apollonius is named after the ancient geometrician Apollonius of Perga. This beautiful geometric construct can be helpful when solving some general problems of geometry and mathematical physics, optics, and electricity. Here we discuss two of its applications: localizing an object in space and calculating electric fields. First, we…

  11. Ecohydrologic interactions within "fairy circles" in the Namib Desert

    NASA Astrophysics Data System (ADS)

    Ravi, S.; Wang, L.; Kaseke, K. F.; Buynevich, I. V.

    2016-12-01

    Vegetation patterns such as rings, bands and spots are recurrent characteristics of resource limited arid and semi arid ecosystems. One of the most recognizable vegetation patterns is the millions of grass rings, often referred to as "fairy circles", within the arid grassland matrix extending over hundreds of kilometers in the Namib Desert, from southern Angola to northern South Africa. Several modeling studies have highlighted the role of plant-soil interactions in the formation of grass ring patterns. However, little is known about the spatial and temporal variability of hydrological processes inside a ring. In particular, detailed field measurements of hydrological and soil properties inside and outside the fairy circles are limited. We conducted extensive measurements of infiltration rate, soil moisture, grass biometric, and sediment grain size distribution from multiple circles and interspaces in the Namib Desert. Our results indicate that considerable heterogeneity in hydrological processes exists within the rings, resulting from the presence of coarser particles in the bare soil inner areas and concentration of fine soil on the vegetated ring edges. The trapping of aeolian and water-borne sediments by plants may result in the observed soil textural changes beneath the vegetation, which in turn, explains the heterogeneity in hydrological processes, such as infiltration and runoff. We offer experimental evidence for the ecohydrological interactions within fairy circles and discuss the implications of our findings to the "self-organization hypothesis" for their formation.

  12. A Paradigm Shift to Reading around the Hermeneutic Circle.

    ERIC Educational Resources Information Center

    Sparks, Elizabeth E.

    The background, challenge, opportunity, and excitement of hermeneutics can be explored in three signposts of a hermeneutic turn in a doctoral research proposal: from being gifted to gifted reading, from method to interpretation, and from metacognition to the hermeneutic circle. A change in the research site of a study of the metacognitive…

  13. Reading without Teachers: Literature Circles in an EFL Classroom

    ERIC Educational Resources Information Center

    Hsu, Jeng-yih Tim

    2004-01-01

    Unsuccessful college education often turns our students into book haters who will stop reading as soon as they graduate. The idea of literature circles embraces the concept of "reading for fun" and is intended to create more independent readers and book addicts who will continuously read for the rest of their lives. Pioneers in literacy…

  14. Quality Circles in the Community College. ERIC Digest.

    ERIC Educational Resources Information Center

    ERIC Clearinghouse for Junior Colleges, Los Angeles, CA.

    Quality Circles (QC's) consist of small groups of people who perform the same work and who voluntarily meet on a regular basis to discuss problems, seek solutions, and cooperate with management in the implementation of those solutions. QC's operate on the premise that employee participation in decision making and problem solving improves the…

  15. Optimizing care in osteoporosis: The Canadian quality circle project

    PubMed Central

    Ioannidis, George; Thabane, Lehana; Gafni, Amiram; Hodsman, Anthony; Kvern, Brent; Johnstone, Dan; Plumley, Nathalie; Salach, Lena; Jiwa, Famida; Adachi, Jonathan D; Papaioannou, Alexandra

    2008-01-01

    Background While the Osteoporosis Canada 2002 Canadian guidelines provided evidence based strategies in preventing, diagnosing, and managing this condition, publication and distribution of guidelines have not, in and of themselves, been shown to alter physicians clinical approaches. We hypothesize that primary care physicians enrolled in the Quality Circle project would change their patient management of osteoporosis in terms of awareness of osteoporosis risk factors and bone mineral density testing in accordance with the guidelines. Methods The project consisted of five Quality Circle phases that included: 1) Training & Baseline Data Collection, 2) First Educational Intervention & First Follow-Up Data Collection 3) First Strategy Implementation Session, 4) Final Educational Intervention & Final Follow-up Data Collection, and 5) Final Strategy Implementation Session. A total of 340 circle members formed 34 quality circles and participated in the study. The generalized estimating equations approach was used to model physician awareness of risk factors for osteoporosis and appropriate utilization of bone mineral density testing pre and post educational intervention (first year of the study). Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated. Results After the 1st year of the study, physicians' certainty of their patients' risk factor status increased. Certainty varied from an OR of 1.4 (95% CI: 1.1, 1.8) for prior vertebral fracture status to 6.3 (95% CI: 2.3, 17.9) for prior hip fracture status. Furthermore, bone mineral density testing increased in high risk as compared with low risk patients (OR: 1.4; 95% CI: 1.2, 1.7). Conclusion Quality Circle methodology was successful in increasing both physicians' awareness of osteoporosis risk factors and appropriate bone mineral density testing in accordance with the 2002 Canadian guidelines. PMID:18828906

  16. Types of the cerebral arterial circle (circle of Willis) in a Sri Lankan Population

    PubMed Central

    2011-01-01

    Background The variations of the circle of Willis (CW) are clinically important as patients with effective collateral circulations have a lower risk of transient ischemic attack and stroke than those with ineffective collaterals. The aim of the present cadaveric study was to investigate the anatomical variations of the CW and to compare the frequency of prevalence of the different variations with previous autopsy studies as variations in the anatomy of the CW as a whole have not been studied in the Indian subcontinent. Methods The external diameter of all the arteries forming the CW in 225 normal Sri Lankan adult cadaver brains was measured using a calibrated grid to determine the prevalence in the variation in CW. Chisquared tests and a correspondence analysis were performed to compare the relative frequencies of prevalence of anatomical variations in the CW across 6 studies of diverse ethnic populations. Results We report 15 types of variations of CW out of 22 types previously described and one additional type: hypoplastic precommunicating part of the anterior cerebral arteries (A1) and contralateral posterior communicating arteries (PcoA) 5(2%). Statistically significant differences (p < 0.0001) were found between most of the studies except for the Moroccan study. An especially notable difference was observed in the following 4 configurations: 1) hypoplastic precommunicating part of the posterior cerebral arteries (P1), and contralateral A1, 2) hypoplastic PcoA and contralateral P1, 3) hypoplastic PcoA, anterior communicating artery (AcoA) and contralateral P1, 4) bilateral hypoplastic P1s and AcoA in a Caucasian dominant study by Fisher versus the rest of the studies. Conclusion The present study reveals that there are significant variations in the CW among intra and inter ethnic groups (Caucasian, African and Asian: Iran and Sri Lanka dominant populations), and warrants further studies keeping the methods of measurements, data assessment, and the definitions

  17. The C-Circle Assay for alternative-lengthening-of-telomeres activity.

    PubMed

    Henson, Jeremy D; Lau, Loretta M; Koch, Sylvia; Martin La Rotta, Nancy; Dagg, Rebecca A; Reddel, Roger R

    2017-02-01

    The C-Circle Assay has satisfied the need for a rapid, robust and quantitative ALT assay that responds quickly to changes in ALT activity. The C-Circle Assay involves (i) extraction or simple preparation (Quick C-Circle Preparation) of the cell's DNA, which includes C-Circles (ii) amplification of the self-primed C-Circles with a rolling circle amplification reaction and (iii) sequence specific detection of the amplification products by native telomeric DNA dot blot or telomeric qPCR. Here we detail the protocols and considerations required to perform the C-Circle Assay and its controls, which include exonuclease removal of linear telomeric DNA, production of the synthetic C-Circle C96 and modulation of ALT activity by γ-irradiation.

  18. Playing favorites: the influence of leaders' inner circle on group processes and performance.

    PubMed

    Burris, Ethan R; Rodgers, Matthew S; Mannix, Elizabeth A; Hendron, Michael G; Oldroyd, James B

    2009-09-01

    Leaders frequently form stronger relationships with certain subordinates moreso than others, creating an inner circle of close friendships and an outer circle of more distant relationships. Three studies examine the effects of inner-circle membership on group dynamics and interpersonal influence in hierarchical teams. Study 1 finds that, compared to outer-circle members, inner-circle members feel safer and participate in the group discussion more, and leaders recognize them as making a greater contribution and allocate a larger bonus to them. Consequently, inner-circle members influence the groups' decisions more, and team decision quality improves when inner-circle members possess expert knowledge. Study 2 finds that leaders attended to and recalled suggestions from their inner circle more regardless of argument strength, suggesting heuristic information processing. Study 3 replicates these findings using intact teams in a large governmental agency. Implications for leadership and group decision making are discussed.

  19. Topographic control of sorted circle morphology on Svalbard

    NASA Astrophysics Data System (ADS)

    Voigt, Joana; Hauber, Ernst; Reiss, Dennis; Hiesinger, Harald; Johnsson, Andreas; van Gasselt, Stephan; Balme, Matt; Head, Jim; de Verra, Jean-Pierre; Steinbrügge, Gregor; Jaumann, Ralf

    2015-04-01

    Patterned ground is a typical phenomenon in polar, subpolar and alpine regions [1]. As it is commonly (but not necessarily!) related to freeze-thaw cycles, its presence on Mars could possibly point to locations and periods where and when liquid water existed in the recent past [2]. Sorted circles are a class of patterned ground that was tentatively identified in Elysium Planitia (Mars) [3], but this interpretation has been challenged on the basis of physical considerations [4]. Without direct access to potential patterned ground on Mars, the analysis of terrestrial analogues can inform the interpretation of Martian landforms. Svalbard (Norway) offers a wide variety of permafrost features that are morphologically analogous to Martian cold-climate landforms [5]. It hosts some of the best examples of sorted circles on Earth, which are located on the westernmost tip of Brøgger peninsula, on a broad strand flat that is characterized by a series of postglacial beach ridges [6]. Here we report on our analysis of sorted circle morphology (especially their plan-view shape, i.e. their "roundness" or ellipticity) and its correlation with local topography (slopes, curvature). Sorted circle morphology was determined from HRSC-AX images (for details on the flight campaign and image properties see ref [5]) and through field work. Topographic information comes from a 50 cm gridded DEM derived from HRSC-AX stereo images. We measured sorted circle morphology (ellipticity, azimuth of major axis) along a WNW-ESE traverse that runs from the inland towards the sea and is oriented perpendicular to the local beach ridge trend. Selected areas with homogeneous sorted circle appearance were visually mapped, and compared to the average slope, aspect, and the calculated topographic wetness index (TWI). Furthermore the whole traverse was classified into four different morphologies of the sorted patterned ground (sorted circles, sorted "ellipses", sorted nets and areas without patterned ground

  20. Late Mousterian persistence near the Arctic Circle.

    PubMed

    Slimak, Ludovic; Svendsen, John Inge; Mangerud, Jan; Plisson, Hugues; Heggen, Herbjørn Presthus; Brugère, Alexis; Pavlov, Pavel Yurievich

    2011-05-13

    Palaeolithic sites in Russian high latitudes have been considered as Upper Palaeolithic and thus representing an Arctic expansion of modern humans. Here we show that at Byzovaya, in the western foothills of the Polar Urals, the technological structure of the lithic assemblage makes it directly comparable with Mousterian Middle Palaeolithic industries that so far have been exclusively attributed to the Neandertal populations in Europe. Radiocarbon and optical-stimulated luminescence dates on bones and sand grains indicate that the site was occupied during a short period around 28,500 carbon-14 years before the present (about 31,000 to 34,000 calendar years ago), at the time when only Upper Palaeolithic cultures occupied lower latitudes of Eurasia. Byzovaya may thus represent a late northern refuge for Neandertals, about 1000 km north of earlier known Mousterian sites.

  1. "Vicious circles": the development of morbid obesity.

    PubMed

    Owen-Smith, Amanda; Donovan, Jenny; Coast, Joanna

    2014-09-01

    Although there has been extensive research around the etiology of moderate obesity, there are still important questions relating to the development and lived experience of extreme obesity. We present a synthesis of data from two in-depth qualitative studies in which morbidly obese participants (N = 31) were able to explain the development of the condition in their own terms. We identified consistent themes in the two datasets, and undertook a detailed data synthesis. Particularly salient themes in the development of morbid obesity related to family structures and early socialization experiences, and the role of emotional distress was dominant in both initial weight gain and ongoing cycles of loss and regain. All informants accepted some responsibility for their health state, but identified a number of mitigating factors that limited personal culpability that were often related to the fulfillment of gendered social expectations.

  2. Getting Started with Literature Circles. The Bill Harp Professional Teachers Library Series.

    ERIC Educational Resources Information Center

    Noe, Katherine L. Schlick; Johnson, Nancy J.

    Designed to help teachers get started using literature circles in their classrooms, this book gives teachers a boost to begin, offers some insights from other teachers, and helps teachers clarify where to go next. It notes that literature circles (or literature study groups, book clubs, or discussion circles) take many forms and engage students in…

  3. Building Strong Neighborhoods: A Study Circle Guide for Public Dialogue and Community Problem Solving.

    ERIC Educational Resources Information Center

    Leighninger, Matt; Flavin-McDonald, Catherine; Ghandour, Reem

    This document explains how to establish study circles for public dialogue and community problem solving with the aim of building strong neighborhoods. The foreword explains the value of study circles in addressing the challenges currently facing all kinds of neighborhoods and presents 10 specific guidelines for organizing study circles in a…

  4. The Chicken and the Egg: Inviting Response and Talk through Socratic Circles

    ERIC Educational Resources Information Center

    Styslinger, Mary E.; Pollock, Timothy

    2010-01-01

    This collaborative inquiry answers the following questions: 1) What is the nature of talk during Socratic Circles? 2) What is student response to talk? 3) How might knowing more about student response to talk and the nature of talk improve teaching during Socratic Circles? The article first describes the process of implementing Socratic Circles,…

  5. Native American Values and Management Education: Envisioning an Inclusive Virtuous Circle

    ERIC Educational Resources Information Center

    Verbos, Amy Klemm; Gladstone, Joe S.; Kennedy, Deanna M.

    2011-01-01

    Circles are symbols of interconnectedness. Behavioral circles can be vicious or virtuous. Many American Indians are caught in a vicious circle of exclusion from the purported benefits of Westernization, entrapment in its negative elements, and the ongoing undermining of their culture and thus their identities. Yet Native Americans, along with many…

  6. Expanding the Reach of Extension to Underserved Audiences through Study Circles in Rural Idaho

    ERIC Educational Resources Information Center

    Cummins, Melissa; Petty, Barbara; Hansen, Lyle; Hoffman, Katie; Wittman, Grace

    2012-01-01

    Extension educators expanded the reach of their programming to underserved audiences through the implementation of Study Circles in rural Southern Idaho. Study Circles gave educators entry into communities by establishing relationships necessary for long-term change. Study Circle discussions in rural Southern Idaho led to stronger relationships…

  7. 77 FR 55691 - Establishment of Class E Airspace; Circle Town, MT

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-11

    ...This action establishes Class E airspace at Circle Town County Airport, Circle Town, MT to accommodate aircraft using new Area Navigation (RNAV) Global Positioning System (GPS) standard instrument approach procedures at Circle Town County Airport. This improves the safety and management of Instrument Flight Rules (IFR) operations at the...

  8. First the Look and Then the Sound: Creating Conversations at Circle Time.

    ERIC Educational Resources Information Center

    Kantor, Rebecca; And Others

    Presented is an interactional analysis of preschool circle time that builds on the view of classrooms as social systems within the broader culture of schooling. In the preschool studied, 18 children, 2 teachers, and several student teachers learned to use circle time together. The head teacher's approach to circle time was a developmental one,…

  9. National Forest System working circles: a question of size and ownership composition

    Treesearch

    Robert J. Hrubes

    1976-01-01

    Allowable-cut (potential yield) levels on National Forest land are determined for planning units called working circles. The size of working circles has been increased over the past 30 years to the present scale which is often coincident with National Forest boundaries. Larger working circles have recently been considered because of the anticipated impacts on timber...

  10. Quality Circles: Implications for Training. Overview: ERIC Fact Sheet No. 24.

    ERIC Educational Resources Information Center

    Imel, Susan

    Quality circles are part of the movement to provide workers with increased autonomy, responsibility, and authority. Key elements of quality circles are the characteristics of their members, volunteer participation, regular meetings, training, problem identification, and solution implementation. The theoretical bases of quality circles include:…

  11. Around the CIRCLE: Research and Practice. Volume 5, Number 1, Fall 2007

    ERIC Educational Resources Information Center

    Center for Information and Research on Civic Learning and Engagement (CIRCLE), 2007

    2007-01-01

    The Center for Information and Research on Civic Learning and Engagement (CIRCLE) promotes research on the civic and political engagements of Americans between the ages of 15 and 25. The following topics are covered in this issue of "Around the CIRCLE": (1) Common Social Studies Teaching Practices and their Civic Outcomes; (2) CIRCLE Jointly Hosts…

  12. Calculation of Latitude and Longitude for Points on Perimeter of a Circle on a Sphere

    SciTech Connect

    Morris, Heidi E.

    2015-08-14

    This document describes the calculation of the Earth-Centered Earth Fixed (ECEF) coordinates for points lying on the perimeter of a circle. Here, the perimeter of the circle lies on the surface of the sphere and the center of the planar circle is below the surface. These coordinates are converted to latitude and longitude for mapping fields on the surface of the earth.

  13. Native American Values and Management Education: Envisioning an Inclusive Virtuous Circle

    ERIC Educational Resources Information Center

    Verbos, Amy Klemm; Gladstone, Joe S.; Kennedy, Deanna M.

    2011-01-01

    Circles are symbols of interconnectedness. Behavioral circles can be vicious or virtuous. Many American Indians are caught in a vicious circle of exclusion from the purported benefits of Westernization, entrapment in its negative elements, and the ongoing undermining of their culture and thus their identities. Yet Native Americans, along with many…

  14. Getting Started with Literature Circles. The Bill Harp Professional Teachers Library Series.

    ERIC Educational Resources Information Center

    Noe, Katherine L. Schlick; Johnson, Nancy J.

    Designed to help teachers get started using literature circles in their classrooms, this book gives teachers a boost to begin, offers some insights from other teachers, and helps teachers clarify where to go next. It notes that literature circles (or literature study groups, book clubs, or discussion circles) take many forms and engage students in…

  15. The Chicken and the Egg: Inviting Response and Talk through Socratic Circles

    ERIC Educational Resources Information Center

    Styslinger, Mary E.; Pollock, Timothy

    2010-01-01

    This collaborative inquiry answers the following questions: 1) What is the nature of talk during Socratic Circles? 2) What is student response to talk? 3) How might knowing more about student response to talk and the nature of talk improve teaching during Socratic Circles? The article first describes the process of implementing Socratic Circles,…

  16. From EUCLID to Ptolemy in English Crop Circles

    NASA Astrophysics Data System (ADS)

    Hawkins, G. S.

    1997-12-01

    The late Lord Soli Zuckerman, science advisor to several British governments, encouraged the author, an astronomer, to test the theory that all crop circles were made by hoaxers. Within the hundreds of formations in Southern England he saw a thread of surprising historical content at the intellectual level of College Dons. One diagram in celestial mechanics involved triple conjunctions of Mercury, Venus and Mars every 67 2/3 years. Ptolemy's fourth musical scale, tense diatonic, occurred in the circles during the period 1978-88. Starting on E, Ptolemaic ratios make our perfect diatonic scale of white notes on the keyboard of the piano or church organ. For separated circles the ratio was given by diameters, and for concentric circles it was diameters squared. A series of rotationally symmetric figures began in 1988 which combined Ptolemy's ratios with Euclid's theorems. In his last plane theorem, Euclid (Elements 13,12) proved that the square on the side of an equilateral triangle is 3 times the square on the circum-circle radius -- diatonic note G(2). From the 1988 figure one can prove the square on the side is 16/3 times the square on the semi-altitude, giving note F(3). Later rotational figures over the next 5 years led to diatonic ratios for the hexagon, square and triangle. They gave with the exactness of Euclidean theorems the notes F, C(2) and E(2), and they are the only regular polygons to do so. Although these 4 crop theorems derive from Euclid, they were previously unknown as a set in the literature, nor had the Ptolemaic connection been published. Professional magazines asked the readers to provide a fifth theorem that would generate the above 4 theorems, but none was forthcoming. Ultimately the cicle makers showed knowledge of this generating theorem using a 200-ft design at Litchfield, Hampshire. After 1993, rotationally symmetric geometries continued to appear, but with much more complicated patterns. One design showed 6 crescent moons in a hexagon

  17. Detection of the optic nerve head in fundus images of the retina using the Hough transform for circles.

    PubMed

    Zhu, Xiaolu; Rangayyan, Rangaraj M; Ells, Anna L

    2010-06-01

    Detection of the optic nerve head (ONH) is a key preprocessing component in algorithms for the automatic extraction of the anatomical structures of the retina. We propose a method to automatically locate the ONH in fundus images of the retina. The method includes edge detection using the Sobel operators and detection of circles using the Hough transform. The Hough transform assists in the detection of the center and radius of a circle that approximates the margin of the ONH. Forty images of the retina from the Digital Retinal Images for Vessel Extraction (DRIVE) dataset were used to test the performance of the proposed method. The center and boundary of the ONH were independently marked by an ophthalmologist for evaluation. Free-response receiver operating characteristics (FROC) analysis as well as measures of distance and overlap were used to evaluate the performance of the proposed method. The centers of the ONH were detected with an average distance of 0.36 mm to the corresponding centers marked by the ophthalmologist; the detected circles had an average overlap of 0.73 with the boundaries of the ONH drawn by the ophthalmologist. FROC analysis indicated a sensitivity of detection of 92.5% at 8.9 false-positives per image. With an intensity-based criterion for the selection of the circle and a limit of 40 pixels (0.8 mm) on the distance between the center of the detected circle and the manually identified center of the ONH, a successful detection rate of 90% was obtained with the DRIVE dataset.

  18. A connection between orthogonal polynomials on the unit circle and matrix orthogonal polynomials on the real line

    NASA Astrophysics Data System (ADS)

    Cantero, M. J.; Ferrer, M. P.; Moral, L.; Velázquez, L.

    2003-05-01

    Szego's procedure to connect orthogonal polynomials on the unit circle and orthogonal polynomials on [-1,1] is generalized to nonsymmetric measures. It generates the so-called semi-orthogonal functions on the linear space of Laurent polynomials [Lambda], and leads to a new orthogonality structure in the module [Lambda]×[Lambda]. This structure can be interpreted in terms of a 2×2 matrix measure on [-1,1], and semi-orthogonal functions provide the corresponding sequence of orthogonal matrix polynomials. This gives a connection between orthogonal polynomials on the unit circle and certain classes of matrix orthogonal polynomials on [-1,1]. As an application, the strong asymptotics of these matrix orthogonal polynomials is derived, obtaining an explicit expression for the corresponding Szego's matrix function.

  19. Rolling Circle Amplification of Complete Nematode Mitochondrial Genomes

    PubMed Central

    Tang, Sha; Hyman, Bradley C.

    2005-01-01

    To enable investigation of nematode mitochondrial DNA evolution, methodology has been developed to amplify intact nematode mitochondrial genomes in preparative yields using a rolling circle replication strategy. Successful reactions were generated from whole cell template DNA prepared by alkaline lysis of the rhabditid nematode Caenorhabditis elegans and a mermithid nematode, Thaumamermis cosgrovei. These taxa, representing the two major nematode classes Chromodorea and Enoplea, maintain mitochondrial genomes of 13.8 kb and 20.0 kb, respectively. Efficient amplifications were conducted on template DNA isolated from individual or pooled nematodes that were alive or stored at -80°C. Unexpectedly, these experiments revealed that multiple T. cosgrovei mitochondrial DNA haplotypes are maintained in our local population. Rolling circle amplification products can be used as templates for standard PCR reactions with specific primers that target mitochondrial genes or for direct DNA sequencing. PMID:19262866

  20. Culture Circles in adolescent empowerment for the prevention of violence.

    PubMed

    Monteiro, Estela Maria Leite Meirelles; Neto, Waldemar Brandão; de Lima, Luciane Soares; de Aquino, Jael Maria; Gontijo, Daniela Tavares; Pereira, Beatriz Oliveira

    2015-04-03

    An action research based on Paulo Freire's Culture Circles was developed to implement a health education intervention involving adolescents, in collective knowledge construction about strategies for the prevention of violence. The data collection in the Culture Circles involved 11 adolescents and included observation and field diary, photographic records and recording. The educational action aroused a critical socio-political and cultural position in the adolescents towards the situations of vulnerability to violence, including the guarantee of human rights, justice and the combat of inequities; changes in the social relations, combat against discrimination and intolerance; expansion of access and reorientation of health services through intersectoral public policies. The intervention empowered the group of adolescents for the prevention of violence and permitted the inclusion of health professionals in the school context, from an interdisciplinary perspective, contributing to the establishment of social support and protection networks.

  1. Culture Circles in adolescent empowerment for the prevention of violence

    PubMed Central

    Monteiro, Estela Maria Leite Meirelles; Neto, Waldemar Brandão; de Lima, Luciane Soares; de Aquino, Jael Maria; Gontijo, Daniela Tavares; Pereira, Beatriz Oliveira

    2015-01-01

    An action research based on Paulo Freire's Culture Circles was developed to implement a health education intervention involving adolescents, in collective knowledge construction about strategies for the prevention of violence. The data collection in the Culture Circles involved 11 adolescents and included observation and field diary, photographic records and recording. The educational action aroused a critical socio-political and cultural position in the adolescents towards the situations of vulnerability to violence, including the guarantee of human rights, justice and the combat of inequities; changes in the social relations, combat against discrimination and intolerance; expansion of access and reorientation of health services through intersectoral public policies. The intervention empowered the group of adolescents for the prevention of violence and permitted the inclusion of health professionals in the school context, from an interdisciplinary perspective, contributing to the establishment of social support and protection networks. PMID:25931647

  2. Landscapes, Circles and Antikythera: The Birth of the Mechanical Universe

    NASA Astrophysics Data System (ADS)

    Edmunds, M. G.

    The joint Greek/UK/US Antikythera Mechanism Research Project is currently producing a definitive set of experimental optical and X-ray imaging data of the Mechanism. The interpretation will require a good knowledge of the context in which it was made. Following from the sacred landscapes of northern Europe it is difficult to escape the symbolism of the "circle" in prehistoric cosmologies, and the pre-eminence of the circle in Greek astronomical thought is obvious. Is the "circular" ikon of the main wheel in Antikythera Mechanism simply another gear wheel, or might ideas of cosmology have influenced its design? How important would devices like the Antikythera Mechanism have been in providing a physical model of the Universe , pushing mathematical abstraction into reality? The relevance of the Mechanism is understanding the development of ideas and philosophy, particularly determinism is emphasized.

  3. Abundance of Mode-Locking for Quasiperiodically Forced Circle Maps

    NASA Astrophysics Data System (ADS)

    Wang, J.; Jäger, T.

    2017-07-01

    We study the phenomenon of mode-locking in the context of quasiperiodically forced non-linear circle maps. As a main result, we show that under certain C^1-open condition on the geometry of twist parameter families of such systems, the closure of the union of mode-locking plateaus has positive measure. In particular, this implies the existence of infinitely many mode-locking plateaus (open Arnold tongues). The proof builds on multiscale analysis and parameter exclusion methods in the spirit of Benedicks and Carleson, which were previously developed for quasiperiodic SL(2,R)-cocycles by Young and Bjerklöv. The methods apply to a variety of examples, including a forced version of the classical Arnold circle map.

  4. Rolling circle amplification of complete nematode mitochondrial genomes.

    PubMed

    Tang, Sha; Hyman, Bradley C

    2005-06-01

    To enable investigation of nematode mitochondrial DNA evolution, methodology has been developed to amplify intact nematode mitochondrial genomes in preparative yields using a rolling circle replication strategy. Successful reactions were generated from whole cell template DNA prepared by alkaline lysis of the rhabditid nematode Caenorhabditis elegans and a mermithid nematode, Thaumamermis cosgrovei. These taxa, representing the two major nematode classes Chromodorea and Enoplea, maintain mitochondrial genomes of 13.8 kb and 20.0 kb, respectively. Efficient amplifications were conducted on template DNA isolated from individual or pooled nematodes that were alive or stored at -80 degrees C. Unexpectedly, these experiments revealed that multiple T. cosgrovei mitochondrial DNA haplotypes are maintained in our local population. Rolling circle amplification products can be used as templates for standard PCR reactions with specific primers that target mitochondrial genes or for direct DNA sequencing.

  5. Micro-IBA analysis of Au/Si eutectic "crop-circles"

    NASA Astrophysics Data System (ADS)

    Amato, Giampiero; Battiato, Alfio; Croin, Luca; Jaksic, Milko; Siketic, Zdravko; Vignolo, Umberto; Vittone, Ettore

    2015-04-01

    When a thin gold layer is deposited onto the native oxide of a silicon wafer and is annealed at temperatures greater than 600 °C, peculiar circular features, few micrometers in diameter, with a regular polygon at the centre of each circle, reminiscent of so called "alien" crop circles, can be observed. A model has been recently proposed in Matthews et al. [1], where the formation of such circular structures is attributed to the interdiffusion of gold and silicon through holes in the native oxide induced by the weakening of the amorphous silica matrix occurring during the annealing process. The rupture of the liquid Au/Si eutectic disc surrounding the pinhole in the oxide causes the debris to be pulled to the edges of the disk, forming Au droplets around it and leaving an empty zone of bare silicon oxide. In this paper, we present a morphological study and a RBS/PIXE analyses of these circular structures, carried out by scanning electron microscopy and by 4 MeV C microbeam, respectively. The results confirm the depletion of gold in the denuded circular zones, and the presence of gold droplets in the centers, which can be attributed to the Au segregation occurring during the cooling stage.

  6. Discovery of fairy circles in Australia supports self-organization theory

    PubMed Central

    Getzin, Stephan; Yizhaq, Hezi; Bell, Bronwyn; Erickson, Todd E.; Postle, Anthony C.; Katra, Itzhak; Tzuk, Omer; Zelnik, Yuval R.; Wiegand, Kerstin; Wiegand, Thorsten; Meron, Ehud

    2016-01-01

    Vegetation gap patterns in arid grasslands, such as the “fairy circles” of Namibia, are one of nature’s greatest mysteries and subject to a lively debate on their origin. They are characterized by small-scale hexagonal ordering of circular bare-soil gaps that persists uniformly in the landscape scale to form a homogeneous distribution. Pattern-formation theory predicts that such highly ordered gap patterns should be found also in other water-limited systems across the globe, even if the mechanisms of their formation are different. Here we report that so far unknown fairy circles with the same spatial structure exist 10,000 km away from Namibia in the remote outback of Australia. Combining fieldwork, remote sensing, spatial pattern analysis, and process-based mathematical modeling, we demonstrate that these patterns emerge by self-organization, with no correlation with termite activity; the driving mechanism is a positive biomass–water feedback associated with water runoff and biomass-dependent infiltration rates. The remarkable match between the patterns of Australian and Namibian fairy circles and model results indicate that both patterns emerge from a nonuniform stationary instability, supporting a central universality principle of pattern-formation theory. Applied to the context of dryland vegetation, this principle predicts that different systems that go through the same instability type will show similar vegetation patterns even if the feedback mechanisms and resulting soil–water distributions are different, as we indeed found by comparing the Australian and the Namibian fairy-circle ecosystems. These results suggest that biomass–water feedbacks and resultant vegetation gap patterns are likely more common in remote drylands than is currently known. PMID:26976567

  7. Content-aware photo collage using circle packing.

    PubMed

    Yu, Zongqiao; Lu, Lin; Guo, Yanwen; Fan, Rongfei; Liu, Mingming; Wang, Wenping

    2014-02-01

    In this paper, we present a novel approach for automatically creating the photo collage that assembles the interest regions of a given group of images naturally. Previous methods on photo collage are generally built upon a well-defined optimization framework, which computes all the geometric parameters and layer indices for input photos on the given canvas by optimizing a unified objective function. The complex nonlinear form of optimization function limits their scalability and efficiency. From the geometric point of view, we recast the generation of collage as a region partition problem such that each image is displayed in its corresponding region partitioned from the canvas. The core of this is an efficient power-diagram-based circle packing algorithm that arranges a series of circles assigned to input photos compactly in the given canvas. To favor important photos, the circles are associated with image importances determined by an image ranking process. A heuristic search process is developed to ensure that salient information of each photo is displayed in the polygonal area resulting from circle packing. With our new formulation, each factor influencing the state of a photo is optimized in an independent stage, and computation of the optimal states for neighboring photos are completely decoupled. This improves the scalability of collage results and ensures their diversity. We also devise a saliency-based image fusion scheme to generate seamless compositive collage. Our approach can generate the collages on nonrectangular canvases and supports interactive collage that allows the user to refine collage results according to his/her personal preferences. We conduct extensive experiments and show the superiority of our algorithm by comparing against previous methods.

  8. Chirality in microswimmer motion: From circle swimmers to active turbulence

    NASA Astrophysics Data System (ADS)

    Löwen, Hartmut

    2016-11-01

    In this minireview, recent progress in our understanding of the basic physical principles of microswimmers which perform a motion characterized by chirality is summarized. We discuss both the chiral motion of a single circle swimmer and the occurrence of bacterial turbulence where swirls of different chirality are formed spontaneously in an interacting ensemble of linear microswimmers. Some recent highlights in this context as obtained by theory, simulation and experiment are summarized and briefly discussed.

  9. Social Circles Detection from Ego Network and Profile Information

    DTIC Science & Technology

    2014-12-19

    way of organizing contacts in personal networks. They are therefore currently implemented in the major social net- working systems, such as Facebook ...inadequate for the task. The corpus is composed of 110 egonets retrieved from Facebook , with their Social Circles manually labelled by the egos. They are...representation contains information of the three levels of friendship , giving a value of 1 to the 1st rank relationship, 0.5 to the 2nd rank

  10. SL(2, r) Yang-Mills Theory on a Circle

    NASA Astrophysics Data System (ADS)

    Bengtsson, Ingemar; Hallin, Joakim

    The kinematic of SL(2, ℝ) Yang-Mills theory on a circle is considered, for reasons that are spelt out. The gauge transformations exhibit hyperbolic fixed points, and this results in a physical configuration space with a non-Hausdorff “network” topology. The ambiguity encountered in canonical quantization is then much more pronounced than in the compact case and cannot be resolved through the kind of appeal made to group theory in that case.

  11. Rolling circle amplification detection of RNA and DNA

    DOEpatents

    Christian, Allen T.; Pattee, Melissa S.; Attix, Cristina M.; Tucker, James D.

    2004-08-31

    Rolling circle amplification (RCA) has been useful for detecting point mutations in isolated nucleic acids, but its application in cytological preparations has been problematic. By pretreating cells with a combination of restriction enzymes and exonucleases, we demonstrate RCA in solution and in situ to detect gene copy number and single base mutations. It can also detect and quantify transcribed RNA in individual cells, making it a versatile tool for cell-based assays.

  12. BANQUET SPEECH Full Circle: Star Ferry to Stardust

    NASA Astrophysics Data System (ADS)

    Matthews, Clifford N.

    2008-10-01

    Good evening. I'd like to invite you to join me on a journey that could be entitled “Full Circle: Star Ferry to Stardust”. “Star Ferry” represents Hong Kong, my home town, and especially its university - Hong Kong University - as I knew it during the years of World War II. “Stardust” refers to our gathering here to report on our research on possible organic chemistry in space.

  13. Fucus extract: cosmetic treatment for under-eye dark circles.

    PubMed

    Chavan, Manasi; Sun, Yuhua; Litchauer, Jill; Denis, Alain

    2014-01-01

    Dark circles around the eyes are a complex issue with two main possible causes, the accumulation of melanin in the skin around the eyes and the accumulation of heme resulting from blood leakage. The free heme produced in this manner is highly cytotoxic, proinflammatory and pro-oxidative. To evaluate the effect of Fucus extract on heme oxygenase-1 (HO-1) stimulation activity, and to study its in vitro anti-inflammatory, antioxidative, and collagen stimulation activity. The HO-1 stimulation activity was first evaluated at gene level by reverse transcriptase- polymerase chain reaction targeting specific HO-1 gene, and then followed by Western blot in protein level. The in vitro anti-inflammatory effect was measured by quantification of interleukin-8 (IL-8) level. The in vitro antioxidative activity was measured. Collagen stimulation activity was quantitatively measured by the amount of deposited collagen I in the extracellular matrix. Fucus extract was identified to have HO-1 stimulation activity at both gene and protein level. By stimulating this enzyme, it promotes the degradation of toxic heme to its protective catabolites (CO, Ferritin, and bilirubin) and reduces the source of dark circles. In addition, Fucus extract showed good anti-inflammatory efficacy. The strong antioxidation property of Fucus extract can reduce eye bags and wrinkles while its collagen boosting activity will potentially reduce fine lines and wrinkles. Fucus extract is a novel product that brings a quadruple approach to the treatment of under-eye dark circles.

  14. Comparison between SVPWM two level in internal and external circle of hexagon

    NASA Astrophysics Data System (ADS)

    Giyantara, Andhika; Rameli, Mochammad

    2017-01-01

    This study presents a space vector pulse width modulation (SVPWM) method. Switching time for SVPWM two level is used to generate a sinusoidal waveform from the inverter. This waveform using as input for the induction motor. Usually, we use the internal circle to generate sinusoidal method. However, from the calculation, we can get two different equations, for the internal circle in hexagon and external circle for the hexagon. Comparison between voltage vector in the internal and external circle of hexagon using THD (Total Harmonic Distortion) value for each circle.

  15. Circles of support and accountability: The characteristics of core members in England and Wales.

    PubMed

    Clarke, Martin; Warwick, Leah; Völlm, Birgit

    2017-04-01

    Circles of support and accountability, or Circles, use community volunteers to help reintegrate sex offenders at risk of reoffending in the community. The aims of this study are to describe the first 275 male sex offenders ('core members') in England and Wales supported by a Circle and to compare those attending the five largest Circles. As part of their monitoring activity, 10 Circles extracted data from case files, anonymised it and submitted it to Circles UK, the national oversight body. Circles have expanded rapidly with 165 (60%) of Circles commencing in the three years 2011-2013 compared with 110 in the nine years 2002-2010. Most core members were referred from the Probation Service (82%). Circles were provided to men with a range of predicted risks of reoffending - from low (26%) to very high (12%). There were some positive changes between the beginning and end of Circles, such as fewer men being unemployed and more living in their own chosen accommodation. Circles have been used to support the reintegration of a wide range of sex offenders. Given their rapid growth and flexibility, consistent recording standards are required across. These standards should be reviewed periodically to ensure all important fields of change are captured, including frequency of attendance, length per session and quality of engagement in the work. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  16. Can the Expanding Circle Own English? Comments on Yoo's "Nonnative Teachers in the Expanding Circle and the Ownership of English"

    ERIC Educational Resources Information Center

    Ren, Wei

    2014-01-01

    Yoo's (2014) article raises a number of questions concerning local teachers' status and the ownership of English in the Expanding Circle. In this article, I address five issues that I see as most important relating to the ownership of English and empowering local teachers in the Expanding Circle. I provide up-to-date evidence of World…

  17. Can the Expanding Circle Own English? Comments on Yoo's "Nonnative Teachers in the Expanding Circle and the Ownership of English"

    ERIC Educational Resources Information Center

    Ren, Wei

    2014-01-01

    Yoo's (2014) article raises a number of questions concerning local teachers' status and the ownership of English in the Expanding Circle. In this article, I address five issues that I see as most important relating to the ownership of English and empowering local teachers in the Expanding Circle. I provide up-to-date evidence of World…

  18. Plasmid rolling-circle replication: highlights of two decades of research.

    PubMed

    Khan, Saleem A

    2005-03-01

    This review provides a historical perspective of the major findings that contributed to our current understanding of plasmid rolling-circle (RC) replication. Rolling-circle-replicating (RCR) plasmids were discovered approximately 20 years ago. The first of the RCR plasmids to be identified were native to Gram-positive bacteria, but later such plasmids were also identified in Gram-negative bacteria and in archaea. Further studies revealed mechanistic similarities in the replication of RCR plasmids and the single-stranded DNA bacteriophages of Escherichia coli, although there were important differences as well. Three important elements, a gene encoding the initiator protein, the double strand origin, and the single strand origin, are contained in all RCR plasmids. The initiator proteins typically contain a domain involved in their sequence-specific binding to the double strand origin and a domain that nicks within the double strand origin and generates the primer for DNA replication. The double strand origins include the start-site of leading strand synthesis and contain sequences that are bound and nicked by the initiator proteins. The single strand origins are required for synthesis of the lagging strand of RCR plasmids. The single strand origins are non-coding regions that are strand-specific, and contain extensive secondary structures. This minireview will highlight the major findings in the study of plasmid RC replication over the past twenty years. Regulation of replication of RCR plasmids will not be included since it is the subject of another review.

  19. Numerical simulations of the blood flow in the patient-specific arterial cerebral circle region.

    PubMed

    Reorowicz, Piotr; Obidowski, Damian; Klosinski, Przemyslaw; Szubert, Wojciech; Stefanczyk, Ludomir; Jozwik, Krzysztof

    2014-05-07

    The Cerebral Circle Region, also known as the Circle of Willis (CoW), is a loop of arteries that form arterial connections between supply arteries to distribute blood throughout the cerebral mass. Among the population, only 25% to 50% have a complete system of arteries forming the CoW. 3D time-varying simulations for three different patient-specific artery anatomies of CoW were performed in order to gain a better insight into the phenomena existing in the cerebral blood flow. The models reconstructed on the basis of computer tomography images start from the aorta and include the largest arteries that supply the CoW and the arteries of CoW. Velocity values measured during the ultrasound examination have been compared with the results of simulations. It is shown that the flow in the right anterior artery in some cases may be supplied from the left internal carotid artery via the anterior communicating artery. The investigations conducted show that the computational fluid dynamic tool, which provides high resolution in both time and space domains, can be used to support physicians in diagnosing patients of different ages and various anatomical arterial structures.

  20. The legendary contributions of Thomas Willis (1621-1675): the arterial circle and beyond.

    PubMed

    Rengachary, Setti S; Xavier, Andrew; Manjila, Sunil; Smerdon, Usha; Parker, Brandon; Hadwan, Suzan; Guthikonda, Murali

    2008-10-01

    Thomas Willis established neurology as a distinct discipline and made significant original contributions to many related fields including anatomy, pathology, cardiology, endocrinology, and gastroenterology. He is most remembered for his work in elucidating the function and anatomy of the circle of Willis. Willis' accomplishments and research methods can be credited in large part to his unconventional medical education which did not include traditional teachings, but rather emphasized learning through clinical practice. Although Willis was not the first to describe the arterial circle, he was the first to describe its function and provide a complete, undisputed illustration through his own innovative use of dye studies. The Willis classification of cranial nerves was still in use over 100 years after its original description. He has also described several disease entities and named many brain structures. Willis' accomplishments in comparative anatomy and understanding the pathophysiology of various diseases through original multidisciplinary experimental work in a clinical setting reveal that he was a true pioneer in translational research.

  1. Morphometry and Variability of the Brain Arterial Circle in Chinchilla (Chinchilla laniger, Molina).

    PubMed

    Kuchinka, Jacek

    2017-02-09

    Arterial circles of brains from 70 adult chinchillas were filled with synthetic latex. The arterial circle of the brain is formed as the result of vertebral arteries being merged into the basilar artery. Caudally, both vertebral arteries gave rise to the ventral spinal artery. The ventral spinal artery splits into tiny cerebellar vessels, the pontine and cochlear branches. Distally, the basilar artery ramified into two terminal branches that formed the arterial circle of brain, rostrally open in most cases (75%). The observed variability of the arterial circle of brain of chinchillas pertained to all elements of that circle. The greatest variability within the vessels of the circle of Willis in chinchillas was observed in 22 cases (31.4%) of internal ophthalmic arteries. In chinchillas, a trend toward slight variability within the arteries comprising the arterial circle of the brain was observed in 44 animals. This accounted for 62.8% of all cases. Only in three cases was the arterial circle of brain clearly symmetrical. At the same time, 23 animals (32.8%) revealed features of significant vascular variability within the brain base region. These consisted of disturbed geometry of the entire arterial circle, different levels of ramifications into individual arteries, as well as the number and diameter of arteries. No internal carotid arteries were observed in chinchillas apart from one atypical case in which the carotid artery extended unilaterally into the basilar artery. These investigations indicate on the significant variability of arterial circle in rodents. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc.

  2. 3-D Reservoir and Stochastic Fracture Network Modeling for Enhanced Oil Recovery, Circle Ridge Phosphoria/Tensleep Reservoir, and River Reservation, Arapaho and Shoshone Tribes, Wyoming

    SciTech Connect

    La Pointe, Paul; Parney, Robert; Eiben, Thorsten; Dunleavy, Mike; Whitney, John; Eubanks, Darrel

    2002-09-09

    The goal of this project is to improve the recovery of oil from the Circle Ridge Oilfield, located on the Wind River Reservation in Wyoming, through an innovative integration of matrix characterization, structural reconstruction, and the characterization of the fracturing in the reservoir through the use of discrete fracture network models.

  3. 3-D Reservoir and Stochastic Fracture Network Modeling for Enhanced Oil Recovery, Circle Ridge Phosphoria/Tensleep Reservoir, and River Reservation, Arapaho and Shoshone Tribes, Wyoming

    SciTech Connect

    La Pointe, Paul R.; Hermanson, Jan

    2002-09-09

    The goal of this project is to improve the recovery of oil from the Circle Ridge Oilfield, located on the Wind River Reservation in Wyoming, through an innovative integration of matrix characterization, structural reconstruction, and the characterization of the fracturing in the reservoir through the use of discrete fracture network models.

  4. Stereoscopic Machine-Vision System Using Projected Circles

    NASA Technical Reports Server (NTRS)

    Mackey, Jeffrey R.

    2010-01-01

    A machine-vision system capable of detecting obstacles large enough to damage or trap a robotic vehicle is undergoing development. The system includes (1) a pattern generator that projects concentric circles of laser light forward onto the terrain, (2) a stereoscopic pair of cameras that are aimed forward to acquire images of the circles, (3) a frame grabber and digitizer for acquiring image data from the cameras, and (4) a single-board computer that processes the data. The system is being developed as a prototype of machine- vision systems to enable robotic vehicles ( rovers ) on remote planets to avoid craters, large rocks, and other terrain features that could capture or damage the vehicles. Potential terrestrial applications of systems like this one could include terrain mapping, collision avoidance, navigation of robotic vehicles, mining, and robotic rescue. This system is based partly on the same principles as those of a prior stereoscopic machine-vision system in which the cameras acquire images of a single stripe of laser light that is swept forward across the terrain. However, this system is designed to afford improvements over some of the undesirable features of the prior system, including the need for a pan-and-tilt mechanism to aim the laser to generate the swept stripe, ambiguities in interpretation of the single-stripe image, the time needed to sweep the stripe across the terrain and process the data from many images acquired during that time, and difficulty of calibration because of the narrowness of the stripe. In this system, the pattern generator does not contain any moving parts and need not be mounted on a pan-and-tilt mechanism: the pattern of concentric circles is projected steadily in the forward direction. The system calibrates itself by use of data acquired during projection of the concentric-circle pattern onto a known target representing flat ground. The calibration- target image data are stored in the computer memory for use as a

  5. The Risks We Dread: A Social Circle Account

    PubMed Central

    Galesic, Mirta; Garcia-Retamero, Rocio

    2012-01-01

    What makes some risks dreadful? We propose that people are particularly sensitive to threats that could kill the number of people that is similar to the size of a typical human social circle. Although there is some variability in reported sizes of social circles, active contact rarely seems to be maintained with more than about 100 people. The loss of this immediate social group may have had survival consequences in the past and still causes great distress to people today. Therefore we hypothesize that risks that threaten a much larger number of people (e.g., 1000) will not be dreaded more than those that threaten to kill “only” the number of people typical for social circles. We found support for this hypothesis in 9 experiments using different risk scenarios, measurements of fear, and samples from different countries. Fear of risks killing 100 people was higher than fear of risks killing 10 people, but there was no difference in fear of risks killing 100 or 1000 people (Experiments 1–4, 7–9). Also in support of the hypothesis, the median number of deaths that would cause maximum level of fear was 100 (Experiments 5 and 6). These results are not a consequence of lack of differentiation between the numbers 100 and 1000 (Experiments 7 and 8), and are different from the phenomenon of “psychophysical numbing” that occurs in the context of altruistic behavior towards members of other communities rather than in the context of threat to one's own community (Experiment 9). We discuss several possible explanations of these findings. Our results stress the importance of considering social environments when studying people's understanding of and reactions to risks. PMID:22509250

  6. Star Formation Beyond the Solar Circle: A Survey of Surveys

    NASA Astrophysics Data System (ADS)

    Kerton, Charles R.

    2013-06-01

    This talk will review and distill the results of major radio, infrared, and combined radio/IR, surveys that have focused on the identification and characterization of active regions of star formation in the outer Galaxy. These surveys reveal that, in terms of star formation activity, the Milky Way beyond the solar circle is not a vast wasteland, but rather it is an area containing numerous regions of star formation well placed for detailed individual study, for large-scale studies of star formation within spiral arms, and for comparative studies with star formation occurring in different environments such as the inner Galaxy and Galactic center.

  7. Fairy circles and their non-local stochastic instability

    NASA Astrophysics Data System (ADS)

    Fuentes, Miguel Angel; Cáceres, Manuel O.

    2017-02-01

    We study analytically a non local stochastic partial differential equation describing a fundamental mechanism for patterns formation, as the one responsible for the so called fairy circles appearing in two different bio-physical scenarios; one on the African continent and another in Australia. Using a stochastic multiscale perturbation expansion, and a minimum coupling approximation we are able to describe the life-times associated to the stochastic evolution from an unstable uniform state to a patterned one. In this way we discuss how two different biological mechanisms can be collapsed in one analytical framework.

  8. Social Circles: A 3D User Interface for Facebook

    NASA Astrophysics Data System (ADS)

    Rodrigues, Diego; Oakley, Ian

    Online social network services are increasingly popular web applications which display large amounts of rich multimedia content: contacts, status updates, photos and event information. Arguing that this quantity of information overwhelms conventional user interfaces, this paper presents Social Circles, a rich interactive visualization designed to support real world users of social network services in everyday tasks such as keeping up with friends and organizing their network. It achieves this by using 3D UIs, fluid animations and a spatial metaphor to enable direct manipulation of a social network.

  9. The Phenomenological Circle and the Unity of Life and Thought.

    PubMed

    Atwood, George E; Stolorow, Robert D

    2016-06-01

    This paper describes the important role of our deep immersions in philosophy in the development of our phenomenological-contextualist approach to psychoanalysis. Influenced most particularly by the phenomenological movement, our collaborative dialogue over more than four decades has led us to a shared commitment to reflection upon the philosophical underpinnings and constitutive contexts of origin of all our theoretical ideas. The growth of our thinking follows an endlessly recurring phenomenological circle joining theoretical perspectives with the inquirers from whose emotional worlds they arise.

  10. The dot-in-circle sign of mycetoma on MRI.

    PubMed

    Kumar, Jyoti; Kumar, Atin; Sethy, Pradeep; Gupta, Somesh

    2007-12-01

    Mycetoma is a chronic granulomatous disease prevalent in tropical countries, but it also occurs in Europe and the United States. Early diagnosis is important as it has therapeutic implications. Although biopsy and microbiological culture provide the definitive diagnosis, these are difficult to achieve in many instances. The dot-in-circle sign is a recently proposed magnetic resonance imaging (MRI) sign of mycetoma, which is likely to be highly specific. We present a case of mycetoma of the thigh with characteristic MRI features. To the best of our knowledge, only 2 cases of mycetoma of the foot demonstrating this sign have been previously published.

  11. From spherical circle coverings to the roundest polyhedra

    NASA Astrophysics Data System (ADS)

    Tarnai, T.; Gáspár, Z.; Lengyel, A.

    2013-11-01

    The problem treated here is: amongst the convex polyhedra that can be circumscribed about the unit sphere and have ? faces, which has the minimum surface area? A new optimization method based on mechanical analogies is worked out to solve this problem. By using this method, new computer-generated solutions are presented for ? and ?. The second of these two conjectured roundest polyhedra has icosahedral symmetry. The relation of the results of this problem to the minimum coverings of the sphere with equal circles is discussed.

  12. Circle of least confusion of a spherical reflector.

    PubMed

    Hosken, Robert W

    2007-06-01

    A simple, tractable equation is provided for determining the size and location of the circle of least confusion of a concave spherical reflector. This method is exact for the object at infinity and with wave effects neglected. Designers of large radius Arecibo-like telescopes, both radio and optical, with symmetrical, spherical primaries should find the method useful. The mathematical results are valid for apertures with an angle of incidence up to 45 degrees. Comparisons of the location of the disk of least confusion with longitudinal spherical aberration and the radius of the disk with transverse spherical aberration are presented.

  13. Path discrepancies between great circle and rhumb line

    NASA Technical Reports Server (NTRS)

    Kaul, R.

    1983-01-01

    A mathematical model for a comparative analysis of great circle vs. rhumb line navigation in the continental United States has been developed at the Avionics Engineering Center, Ohio University. A FORTRAN simulation of the model has been implemented on the IBM 370 computer. The simulation predicts pertinent navigation information for the two flight paths. The basis for the project, which is a part of an M.S. thesis, is to provide a data base for computing discrepancies between the two flight paths. This document briefly describes the model and discusses the implications of the results obtained.

  14. Role of DNA damage and repair in the function of eukaryotic genes: radiation-induced single-strand breaks and their rejoining in chromosomal and extrachromosomal ribosomal DNA of Tetrahymena

    SciTech Connect

    Chiu, S.M.; Oleinick, N.L.

    1980-04-01

    The production and rejoining of single-strand breaks (SSB) in chromosomal DNA and extrachromosomal ribosomal DNA (rDNA) were investigated after sublethal doses of ..gamma.. radiation to exponentially growing Tetrahymena. Hydrogen-3-labeled total nuclear DNA isolated from either control or irradiated cells was heat denatured and electrophoresed in agarose gels containing formaldehyde. Ribosomal DNA was identified by hybridization to (/sup 32/P)rRNA after transferring the DNA from the gels to nitrocellulose strips. It was found that (a) approximately 0.68 SSB is produced in each strand of rDNA exposed to 40 krad; (b) greater than 80% of SSB were rejoined within the first 20 min after irradiation in both chromosomal and rDNA; and (c) the rejoining process in both chromosomal and rDNA proceeded in the presence of inhibitors of protein synthesis, RNA synthesis, or oxidative metabolism. While the majority of SSB induced by 40 krad is rejoined within 20 min after irradiation, the resumption of rRNA synthesis does not occur until 30 min thereafter; it is concluded that the restoration of the normal size of the rDNA template is probably necessary but not sufficient for the resumption of rRNA synthesis.

  15. Participant Experiences of Talking Circles on Type 2 Diabetes in Two Northern Plains American Indian Tribes

    PubMed Central

    Struthers, Roxanne; Hodge, Felicia Schanche; Geishirt-Cantrell, Betty; De Cora, Lorelei

    2011-01-01

    The Talking Circle, a culturally appropriate, 12-week educational intervention, was employed on two Northern Plains American Indian reservations to provide information on type 2 diabetes. In a phenomenological study, funded as a minority supplement to the Talking Circle intervention, the authors asked 8 American Indian participants of the Talking Circle to describe their experience of being an American Indian Talking Circle participant. Seven common themes describe the phenomenon of participating in a Talking Circle diabetic intervention. The Talking Circle technique was effective in providing information on type 2 diabetes through culturally appropriate community sharing. Type 2 diabetes is viewed by both outsiders and those involved as a chronic disease of the utmost concern in American Indian communities. PMID:14556421

  16. Peripapillary circle of Zinn-Haller revealed by fundus fluorescein angiography

    PubMed Central

    Ko, M.; Kim, D.; Ahn, Y.

    1997-01-01

    AIMS—To observe the vascular pattern of the peripapillary circle of Zinn-Haller in humans by fundus fluorescein angiography.
METHODS—307 cases (from 212 patients) of fundus fluorescein angiograms performed in patients with myopic degeneration were evaluated to find the circle of Zinn-Haller and to observe its fundus fluorescein angiographic features.
RESULTS—15 cases (from 13 patients) with the circle of Zinn-Haller were found. It appeared as concentric or zigzag-shaped vascular fillings within the temporal crescent region. All cases were observed in pathological myopia with peripapillary atrophy and a tilted disc. Each arterial circle showed variations in location and shape.
CONCLUSIONS—The temporal part of the circle of Zinn-Haller can be revealed by fundus fluorescein angiography particularly in pathological eyes with prominent peripapillary atrophy and a tilted disc. The morphological variation of this arterial circle should be considered.

 PMID:9349154

  17. Spectra of mothers of premature children about the educative circle of culture.

    PubMed

    Couto, Camila Santos do; Tupinambá, Milena Colares; Rangel, Aldecira Uchôa Monteiro; Frota, Mirna Albuquerque; Martins, Elis Mayre da Costa Silveira; Nobre, Caroline Soares; Landim, Átima Luna Pinheiro

    2014-12-01

    We sought to know the spectra of mothers of premature children regarding their experience with circle of culture of educational character and identifying the learning provided by the circle of culture about newborn care after hospital discharge. A descriptive study was performed in a hospital located in Fortaleza, Brazil. Three meetings of a circle of culture with 17 mothers of premature newborns were performed. The interpretation of the corpus was performed using thematic analysis. Emerged from the categories: Maternal experience in a circle of culture; Promoted social support among mothers through the circle of culture; and Learning provided by the circle of culture. It was concluded that teaching parents during the hospitalization of the child should be held in a way to involve parents in the care of the newborn, provide moments of health education, opportunities for support and dialogue between professionals and family.

  18. Eccentricity on AN Image Caused by Projection of a Circle and a Sphere

    NASA Astrophysics Data System (ADS)

    Matsuoka, R.; Maruyama, S.

    2016-06-01

    Circular targets on a plane are often utilized in photogrammetry, particularly in close range photogrammetry, while spherical targets are sometimes utilized in industrial applications. Both a circle and a sphere are projected as an ellipse onto an image. There is an eccentricity on an image between the centre of the projected ellipse and the projected location of the centre of a circle or a sphere. Since only the centre of the projected ellipse is measured, the correction of the eccentricity is considered to be necessary for highly accurate measurement. This paper shows a process to derive general formulae to calculate an eccentricity of a circle and a sphere using the size and the location of a circle or a sphere, and the focal length, the position and the attitude of a camera. Furthermore the paper shows methods to estimate the eccentricity of a circle and a sphere from the equation of the projected ellipse of a circle or a sphere on an image.

  19. A grounded theory of female adolescents' dating experiences and factors influencing safety: the dynamics of the Circle

    PubMed Central

    Toscano, Sharyl E

    2007-01-01

    Background This paper describes the nature and characteristics of the dating relationships of adolescent females, including any of their experiences of abuse. Methods A grounded theory approach was used with 22 theoretically sampled female adolescents ages 15–18. Results Several important themes emerged: Seven stages of dating consistently described the relationships of female adolescents. A circle consisting of two interacting same sex peer groups provided structure for each teen as they navigated the dating course. The circle was the central factor affecting a female adolescent's potential for risk or harm in dating relationships. Teens defined abuse as an act where the intention is to hurt. Having once succumbed to sexual pressure, teens felt unable to refuse sex in subsequent situations. Conclusion An awareness of both the stages of dating and the dynamics of the circle will assist health care providers to plan and implement interventions in the female adolescent population. Study findings on factors and influences that support non-abusive versus abusive relationship might help identify female teens at risk and/or support interventions aimed at preventing dating violence. PMID:17883833

  20. Feldkamp and circle-and-line cone-beam reconstruction for 3D micro-CT of vascular networks.

    PubMed

    Johnson, R H; Hu, H; Haworth, S T; Cho, P S; Dawson, C A; Linehan, J H

    1998-04-01

    Detailed morphometric knowledge of the microvascular network is needed for studies relating structure to haemodynamic function in organs like the lung. Clinical volumetric CT is limited to millimetre-order spatial resolution. Since evidence suggests that small arterioles (50 to 300 micrometres) dominate pulmonary haemodynamics, we built a micro-CT scanner, capable of imaging excised lungs in 3D with 100 microm resolution, for basic physiology research. The scanner incorporates a micro-focal (3 microm) x-ray source, an xyz theta stage and a CCD-coupled image intensifier detector. We imaged phantoms and contrast-enhanced rat lungs, reconstructing the data with either the Feldkamp or the circle-and-line cone-beam reconstruction algorithm. We present reconstructions using 180 views over 360 degrees for the circular trajectory, augmented with views from a linear scan for the circle-and-line algorithm. Especially for platelike features perpendicular to the rotation axis and remote from the midplane, the circle-and-line algorithm produces superior reconstructions compared with Feldkamp's algorithm. We conclude that the use of nonplanar source trajectories to perform micro-CT on contrast-enhanced, excised lungs can provide data useful for morphometric analysis of vascular trees, currently down to the 130 microm level.

  1. Analyzing Circle of Willis blood flow in ischemic stroke patients through 3D Stroke Arterial Flow Estimation.

    PubMed

    Chien, Aichi; Viñuela, Fernando

    2017-08-01

    Background The objective of ischemic stroke (IS) treatment is to achieve revascularization in cerebral arteries to restore blood flow. However, there is no available method to extract arterial flow data from clinical CTA images. We developed 3D Stroke Arterial Flow Estimation (SAFE), which provides blood flow data throughout the Circle of Willis based on 3D CTA and allows comparison of arterial flow distribution in the brain. Methods We implemented a newly developed 3D vascular reconstruction algorithm for clinical stroke CTA images. Based on the patient-specific vascular structure, SAFE calculates time-resolved blood flow information for the entire Circle of Willis and allows quantitative flow study of IS cases. Clinical IS cases are presented to demonstrate the feasibility. Four patients with CTA images and CT perfusion data were studied. To validate the SAFE analysis, correlation analysis comparing blood flow at the MCA, ICA, and BA was performed. Results Different blood flow patterns were found in individual IS patients. Altered flow patterns and high collateral flow rates were found near occlusions in all cases. Quantitative comparison of blood flow data showed that SAFE obtained flow data and CTP were significantly correlated and provide complementary information about cerebral blood flow for individual patients. Conclusions We present SAFE analysis for collecting detailed time-resolved cerebral arterial flow data in the entire Circle of Willis for IS. Further study with more cases may be important to test the clinical utilization of SAFE and helpful to the study of the underlying hemodynamics of stroke.

  2. Loopback rolling circle amplification for ultrasensitive detection of Kras gene.

    PubMed

    Xu, Huo; Wu, Dong; Jiang, Yifan; Zhang, Rongbo; Wu, Qingzheng; Liu, Yiyun; Li, Feng; Wu, Zai-Sheng

    2017-03-01

    Mutations in Kras gene may be used as a diagnostic marker and a target for treatment of the broad spectrum of human cancers. In this study, we developed a new class of amplification assay, double-hairpin molecular beacon (DHMB)-based cascade rolling circle amplification (RCA), for ultrasensitive and selective detection of Kras gene in a homogenous solution. Specifically, target DNA can hybridize with DHMB and activate cyclical target strand-displacement polymerization (CTDP) and nicking-mediated strand-displacement polymerization (NMDP). The resulting nicked/displaced fragments substantially outnumber target DNA and cause the cascade rolling circle amplification (C-RCA) and nicked fragment-induced strand-displacement polymerization (NFDP). Even if four amplification processes are designed, only DHMB, padlock probe and polymerization primer are involved. Under optimized conditions, this screening system exhibits a linear range of 5 orders of magnitude (from 100fM to 20nM), and the detection limit is down to 16fM. Moreover, the developed biosensing system offers a high assay specificity for perfectly matched target DNA, and the measured data from practical samples demonstrated the potential application in the cancer diagnoses. As a proof-of-concept genetic assay, the novel signaling strategy, as well as desirable analytical capability, would significantly benefit the development of versatile amplification gene profiling platforms, revealing great promise in biological studies and medical diagnostics.

  3. Renormalization of circle diffeomorphisms with a break-type singularity

    NASA Astrophysics Data System (ADS)

    Akhadkulov, Habibulla; Noorani, Mohd Salmi Md; Akhatkulov, Sokhobiddin

    2017-07-01

    Let f be an orientation-preserving circle diffeomorphism with an irrational rotation number and with a break point ξ0, that is, its derivative f\\prime has a jump discontinuity at this point. Suppose that f\\prime satisfies a certain Zygmund condition dependent on a parameter γ>0. We prove that the renormalizations of f are approximated by Möbius transformations in C 1-topology if γ\\in (0, 1] and in C 2-topology if γ\\in (1, +∞). Moreover, it is shown that, in case of γ\\in (1, +∞) the coefficients of Möbius transformations get asymptotically linearly dependent. Further, consider two circle diffeomorphisms with a break point, with the same size of the break and satisfying Zygmund condition with γ\\in (1, +∞). We prove that, under a certain technical condition on rotation numbers, the renormalizations of these diffeomorphisms approach each other in C 2-topology. This paper is dedicated to Professors Akhtam Abdurakhmanovich Dzhalilov and Konstantin Mikhailovich Khanin on the occasion of their 60th birthdays.

  4. Drawing Euler Diagrams with Circles: The Theory of Piercings.

    PubMed

    Stapleton, Gem; Leishi Zhang; Howse, John; Rodgers, Peter

    2011-07-01

    Euler diagrams are effective tools for visualizing set intersections. They have a large number of application areas ranging from statistical data analysis to software engineering. However, the automated generation of Euler diagrams has never been easy: given an abstract description of a required Euler diagram, it is computationally expensive to generate the diagram. Moreover, the generated diagrams represent sets by polygons, sometimes with quite irregular shapes that make the diagrams less comprehensible. In this paper, we address these two issues by developing the theory of piercings, where we define single piercing curves and double piercing curves. We prove that if a diagram can be built inductively by successively adding piercing curves under certain constraints, then it can be drawn with circles, which are more esthetically pleasing than arbitrary polygons. The theory of piercings is developed at the abstract level. In addition, we present a Java implementation that, given an inductively pierced abstract description, generates an Euler diagram consisting only of circles within polynomial time.

  5. Rolling Circle Amplification with Chemically Modified Nucleoside Triphosphates.

    PubMed

    Hollenstein, Marcel; Damha, Masad J

    2016-12-01

    Modified nucleoside triphosphates (dN*TPs) represent facile and versatile precursors for the introduction of chemical diversity into nucleic acids. While dN*TPs have been utilized in a plethora of practical applications, very little attention has been devoted to the assessment of their compatibility with isothermal amplification strategies. In this context, rolling circle amplification (RCA) is a wide-spread enzymatic replication method in which small single-stranded DNA (ssDNA) circles serve as templates in primer extension reactions yielding very long, ssDNA products. RCA is a pivotal tool for the generation of biosensor and diagnostic devices and is currently evaluated for its usefulness to create novel drug delivery systems. This unit describes the experimental procedures for the synthesis of modified RCA products using dN*TPs bearing chemical alterations at any possible location of the nucleosidic scaffold. Two ligation methods are presented for the generation of the DNA nanocircles that serve as templates for RCA, followed by a description of the RCA method itself and an assessment of the nuclease resistance of the ensuing products. © 2016 by John Wiley & Sons, Inc. Copyright © 2016 John Wiley & Sons, Inc.

  6. Federally sponsored multidisciplinary research centers: Learning, evaluation, and vicious circles.

    PubMed

    Youtie, Jan; Corley, Elizabeth A

    2011-02-01

    Despite the increasing investment in multi-year federally funded science and technology centers in universities, there are few studies of how these centers engage in learning and change based on information submitted from various agents in the oversight and evaluation process. One challenge is how to manage and respond to this evaluative information, especially when it is conflicting. Although the center can learn and adapt in response to this information, it can also become subject to a vicious circle of continuous restructuring and production of documentation to address various and potentially inconsistent recommendations. In this paper we illustrate the effects of such a dynamic based on our experiences as external evaluators of the $25 million NSF-funded Learning in Informal and Formal Environments (LIFE) Center. The case study presents an analysis of annual reports and strategic planning documents along with other sources of evidence to illustrate the evolution of center organizational approaches in response to evaluations by external review panels, center evaluators, program managers, and other external stakeholders. We conclude with suggestions for how evaluators may help centers ease the cost of learning and reduce the likelihood of a vicious circle. 2010 Elsevier Ltd. All rights reserved.

  7. [Family practice quality circles between goals and reality--an interaction analysis].

    PubMed

    Weisser, P; Härter, M; Tausch, B

    2000-01-01

    Quality circles are considered a key method for quality assurance in health care. However, there is a lack of systematic evaluation for quality circles in general practice, especially regarding the process quality of quality circle work. This article presents the results of an interaction analysis completing the systematic evaluation of quality circles in general practice in a region of south Germany. Using the so-called conference encoding method for interaction analysis we analyzed 7 out of 25 evaluated quality circles and 2348 interactions between the quality circle members. The participation rate of the moderators is high compared to the relative low contribution of the group members to the quality circle work. We could show that quality circles work topic-oriented, there is a wide exchange of experience between the group members and the group climate is positive. However, there were almost no specific activities to develop guidelines for diagnostic and therapeutic procedures. The results showed a significant discrepancy between the aims of quality circles and their practical realisation. Besides improved option for information and training programs for moderators and participants, we recommend further evaluation studies complemented with specific analysis of the process quality for example with the conference encoding method.

  8. Studies on Escherichia coli sex factors: evidence that covalent circles exist within cells and the general problem of isolation of covalent circles.

    PubMed

    Freifelder, D; Folkmanis, A; Kirschner, I

    1971-03-01

    We examined in detail conditions necessary for making reproducible and for maximizing the amount of deoxyribonucleic acid obtained from a sex factor-containing cell as covalent circles. The results argue that under optimal conditions covalent circles are neither created nor lost during the isolation procedure. The causes of the culture-to-culture variation in recovery of covalent circular deoxyribonucleic acid were investigated but an understanding of this is not yet at hand. Some commonly used conditions which drastically reduce the recovery of covalent circles are described.

  9. Studies on Escherichia coli Sex Factors: Evidence That Covalent Circles Exist Within Cells and the General Problem of Isolation of Covalent Circles

    PubMed Central

    Freifelder, David; Folkmanis, Atis; Kirschner, Ilana

    1971-01-01

    We examined in detail conditions necessary for making reproducible and for maximizing the amount of deoxyribonucleic acid obtained from a sex factor-containing cell as covalent circles. The results argue that under optimal conditions covalent circles are neither created nor lost during the isolation procedure. The causes of the culture-to-culture variation in recovery of covalent circular deoxyribonucleic acid were investigated but an understanding of this is not yet at hand. Some commonly used conditions which drastically reduce the recovery of covalent circles are described. PMID:4926680

  10. A rolling-circle plasmid from Psychrobacter sp. TA144: evidence for a novel rep subfamily.

    PubMed

    Tutino, M L; Duilio, A; Moretti, M A; Sannia, G; Marino, G

    2000-08-02

    In this paper we report the cloning and sequencing of two small plasmids, pTAUp and pTADw, from the Antarctic Gram-negative Psychrobacter sp strain TA144. The observation that pTAUp contains a putative Rep-coding gene (Psyrep) suggested that its duplication occurs via a rolling-circle replication mechanism. This hypothesis was confirmed by the identification of the pTAUp single-stranded DNA form. The putative pTAUp plus origin of replication was found at the 3' end of the Psyrep by using an in vivo complementation assay. Structural similarities at the level of (i) gene organization, (ii) protein sequence, and (iii) nick site sequences strongly suggest that the psychrophilic enzyme belongs to a new subfamily of replication enzymes. Copyright 2000 Academic Press.

  11. Two-circles theorem, q-periodic functions and entangled qubit states

    NASA Astrophysics Data System (ADS)

    Pashaev, Oktay K.

    2014-03-01

    For arbitrary hydrodynamic flow in circular annulus we introduce the two circle theorem, allowing us to construct the flow from a given one in infinite plane. Our construction is based on q-periodic analytic functions for complex potential, leading to fixed scale-invariant complex velocity, where q is determined by geometry of the region. Self-similar fractal structure of the flow with q-periodic modulation as solution of q-difference equation is studied. For one point vortex problem in circular annulus by fixing singular points we find solution in terms of q-elementary functions. Considering image points in complex plane as a phase space for qubit coherent states we construct Fibonacci and Lucas type entangled N-qubit states. Complex Fibonacci curve related to this construction shows reach set of geometric patterns.

  12. Molecular identification of Penicillium marneffei using rolling circle amplification.

    PubMed

    Sun, Jiufeng; Najafzadeh, M J; Zhang, Junmin; Vicente, V A; Xi, Liyan; de Hoog, G S

    2011-11-01

    Penicillium marneffei is the aetiological agent of a severe systemic disease in immunocompromised hosts in Southeast Asia. In the present study, we evaluated an identification method based on rolling circle amplification (RCA) enabling rapid and specific detection of single nucleotide differences. Three padlock probes were designed on the basis of the internal transcribed spacers 1 and 2 (ITS) of the rRNA operon. One of these (PmPL1) allowed specific amplification of P. marneffei DNA within one working day using a newly conceived protocol, while no cross-reactivity was observed with other fungi including related biverticillate penicillia. Amplification products can be detected by electrophoresis on agarose gel. The method provides a powerful tool for a rapid specific identification of P. marneffei in the clinical laboratory and has potential for ecological studies.

  13. The interpersonal circle as a heuristic model for interpersonal research.

    PubMed

    Lorr, M

    1996-04-01

    In this article, I review major advances in the development of the interpersonal circle and its measurement, as delineated by Timothy Leafy (1957) and his colleagues. In my early work (Lorr & McNair, 1963, 1965), an interpersonal Behavior Inventory consisting of manifest behavioral statements was constructed. The 14 categories were found to fit a circular order in several samples. Studies using LaForge and Suczek's (1955) Interpersonal Check List, and Wiggins's (1979) Interpersonal Adjective Scales further established the value of Leary's conceptions and extended them. Several major theorists, researchers, and clinicians including Benjamin, Carson, Horowitz, Kiesler, and Wiggins have been inspired by Leary and, in many cases, have extended his ideas in ways not originally envisioned. Recent research (e.g., Hofstee, de Raad, & Goldberg, 1992; Millon, 1987) demonstrated the pertinence of the interpersonal conception of personality to the 5-factor model and personality disorders.

  14. Literature circles book club for science and language arts

    NASA Astrophysics Data System (ADS)

    Bombard, Britain

    Students from an urban middle school participated in a Science Book Club for one semester using the literature circles format. These students voluntarily attended twice weekly lunch meetings, reading books that followed their Grade 7 science classes. Groups of three to six participants read the same text, each performing rotating jobs to improve group discussions during meetings. When a group completed a book, participants created a presentation to share what they learned with the other groups in the club and the researcher/teacher. This research measured gains in science content knowledge and language arts skills focusing on reading comprehension, and literary response and analysis. Gains were measured using pre-existing district benchmarks. An ANCOVA showed that while no gains were found in science content knowledge, there were gains in language arts in the areas of reading comprehension and literary response and analysis.

  15. Disease spread, susceptibility and infection intensity: vicious circles?

    PubMed

    Beldomenico, Pablo M; Begon, Michael

    2010-01-01

    Epidemiological models and studies of disease ecology typically ignore the role of host condition and immunocompetence when trying to explain the distribution and dynamics of infections and their impact on host dynamics. Recent research, however, indicates that host susceptibility should be considered carefully if we are to understand the mechanism by which parasite dynamics influence host dynamics and vice versa. Studies in insects, fish, amphibians and rodents show that infection occurrence and intensity are more probable and more severe in individuals with an underlying poor condition. Moreover, infection itself results in further deterioration of the host and a 'vicious circle' is created. We argue that this potential synergy between host susceptibility and infection should be more widely acknowledged in disease ecology research.

  16. Brownian motion of a circle swimmer in a harmonic trap.

    PubMed

    Jahanshahi, Soudeh; Löwen, Hartmut; Ten Hagen, Borge

    2017-02-01

    We study the dynamics of a Brownian circle swimmer with a time-dependent self-propulsion velocity in an external temporally varying harmonic potential. For several situations, the noise-free swimming paths, the noise-averaged mean trajectories, and the mean-square displacements are calculated analytically or by computer simulation. Based on our results, we discuss optimal swimming strategies in order to explore a maximum spatial range around the trap center. In particular, we find a resonance situation for the maximum escape distance as a function of the various frequencies in the system. Moreover, the influence of the Brownian noise is analyzed by comparing noise-free trajectories at zero temperature with the corresponding noise-averaged trajectories at finite temperature. The latter reveal various complex self-similar spiral or rosette-like patterns. Our predictions can be tested in experiments on artificial and biological microswimmers under dynamical external confinement.

  17. Quantum walks on a circle with optomechanical systems

    NASA Astrophysics Data System (ADS)

    Moqadam, Jalil Khatibi; Portugal, Renato; de Oliveira, Marcos Cesar

    2015-10-01

    We propose an implementation of a quantum walk on a circle in an optomechanical system by encoding the walker on the phase space of a radiation field and the coin on a two-level state of a mechanical resonator. The dynamics of the system is obtained by applying Suzuki-Trotter decomposition. We numerically show that the system displays typical behaviors of quantum walks, namely the probability distribution evolves ballistically and the standard deviation of the phase distribution is linearly proportional to the number of steps. We also analyze the effects of decoherence by using the phase-damping channel on the coin space, showing the possibility to implement the quantum walk with present-day technology.

  18. Brownian motion of a circle swimmer in a harmonic trap

    NASA Astrophysics Data System (ADS)

    Jahanshahi, Soudeh; Löwen, Hartmut; ten Hagen, Borge

    2017-02-01

    We study the dynamics of a Brownian circle swimmer with a time-dependent self-propulsion velocity in an external temporally varying harmonic potential. For several situations, the noise-free swimming paths, the noise-averaged mean trajectories, and the mean-square displacements are calculated analytically or by computer simulation. Based on our results, we discuss optimal swimming strategies in order to explore a maximum spatial range around the trap center. In particular, we find a resonance situation for the maximum escape distance as a function of the various frequencies in the system. Moreover, the influence of the Brownian noise is analyzed by comparing noise-free trajectories at zero temperature with the corresponding noise-averaged trajectories at finite temperature. The latter reveal various complex self-similar spiral or rosette-like patterns. Our predictions can be tested in experiments on artificial and biological microswimmers under dynamical external confinement.

  19. Digital micromirror device based ophthalmoscope with concentric circle scanning.

    PubMed

    Damodaran, Mathi; Vienola, Kari V; Braaf, Boy; Vermeer, Koenraad A; de Boer, Johannes F

    2017-05-01

    Retinal imaging is demonstrated using a novel scanning light ophthalmoscope based on a digital micromirror device with 810 nm illumination. Concentric circles were used as scan patterns, which facilitated fixation by a human subject for imaging. An annular illumination was implemented in the system to reduce the background caused by corneal reflections and thereby to enhance the signal-to-noise ratio. A 1.9-fold increase in the signal-to-noise ratio was found by using an annular illumination aperture compared to a circular illumination aperture, resulting in a 5-fold increase in imaging speed and a better signal-to-noise ratio compared to our previous system. We tested the imaging performance of our system by performing non-mydriatic imaging on two subjects at a speed of 7 Hz with a maximum 20° (diameter) field of view. The images were shot noise limited and clearly show various anatomical features of the retina with high contrast.

  20. Digital micromirror device based ophthalmoscope with concentric circle scanning

    PubMed Central

    Damodaran, Mathi; Vienola, Kari V.; Braaf, Boy; Vermeer, Koenraad A.; de Boer, Johannes F.

    2017-01-01

    Retinal imaging is demonstrated using a novel scanning light ophthalmoscope based on a digital micromirror device with 810 nm illumination. Concentric circles were used as scan patterns, which facilitated fixation by a human subject for imaging. An annular illumination was implemented in the system to reduce the background caused by corneal reflections and thereby to enhance the signal-to-noise ratio. A 1.9-fold increase in the signal-to-noise ratio was found by using an annular illumination aperture compared to a circular illumination aperture, resulting in a 5-fold increase in imaging speed and a better signal-to-noise ratio compared to our previous system. We tested the imaging performance of our system by performing non-mydriatic imaging on two subjects at a speed of 7 Hz with a maximum 20° (diameter) field of view. The images were shot noise limited and clearly show various anatomical features of the retina with high contrast. PMID:28663905

  1. Circle Hough transform implementation for dots recognition in braille cells

    NASA Astrophysics Data System (ADS)

    Jacinto Gómez, Edwar; Montiel Ariza, Holman; Martínez Sarmiento, Fredy Hernán.

    2017-02-01

    This paper shows a technique based on CHT (Circle Hough Transform) to achieve the optical Braille recognition (OBR). Unlike other papers developed around the same topic, this one is made by using Hough Transform to process the recognition and transcription of Braille cells, proving CHT to be an appropriate technique to go over different non-systematics factors who can affect the process, as the paper type where the text to traduce is placed, some lightning factors, input image resolution and some flaws derived from the capture process, which is realized using a scanner. Tests are performed with a local database using text generated by visual nondisabled people and some transcripts by sightless people; all of this with the support of National Institute for Blind People (INCI for their Spanish acronym) placed in Colombia.

  2. Literature Circles Resource Guide: Teaching Suggestions, Forms, Sample Book Lists and Database [with CD-ROM].

    ERIC Educational Resources Information Center

    Hill, Bonnie Campbell; Noe, Katherine L. Schlick; Johnson, Nancy J.

    This guide provides the practical support teachers need to make literature circles succeed. The information provided in the guide should answer the kinds of questions teachers ask colleagues about implementing literature circles. It is not intended to stand alone. It is designed to supplement and extend two professional books on literature…

  3. Improving the Reading Attitudes of College Students: Using Literature Circles to Learn about Content Reading

    ERIC Educational Resources Information Center

    Bernadowski, Carianne

    2013-01-01

    Literature circles and book clubs have become a popular instructional literacy strategy. In recent years, educators attempt to motivate students to read more in quantity and quality at an early age. A case study design was utilized that required undergraduate education majors to participate in literature circles reading historical fiction and…

  4. Young Puerto Rican Children's Exploration of Racial Discourses within the Figured Worlds of Literature Circles

    ERIC Educational Resources Information Center

    Castrodad-Rodriguez, Patricia Margarita

    2010-01-01

    This study examines the racial discourses of six and seven year old Puerto Rican children participating in small group literature circles over one academic year. The main research question is "How do Puerto Rican young children in a multiage classroom construct race through dialogue within the figured worlds of literature circles?" This study…

  5. Study Circles at the Pharmacy--A New Model for Diabetes Education in Groups.

    ERIC Educational Resources Information Center

    Sarkadi, Anna; Rosenqvist, Urban

    1999-01-01

    Tests the feasibility of a one-year group education model for patients with type 2 diabetes in Sweden. Within study circles led by pharmacists, participants learned to self-monitor glucose, to interpret the results and to act upon them. Results show that study circles held at pharmacies are a feasible way of education persons with type 2 diabetes.…

  6. Toward a "Lifetime of Literacies": Library Reading Circles for College Students

    ERIC Educational Resources Information Center

    Howrey, Mary M.; Rachelson, Esther S.

    2009-01-01

    This qualitative case study of the ReadDeVry reading circles program, a DeVry University funded project, identifies the theoretical and practical considerations for reading circles programs serving college students. As designed, the program addresses a number of the issues raised recently by national organizations such as the American College…

  7. VIEW FROM EAST SIDE OF ELM DRIVE/BIRCH CIRCLE BLOCK, SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW FROM EAST SIDE OF ELM DRIVE/BIRCH CIRCLE BLOCK, SHOWING SLOPING TOPOGRAPHY. VIEW FACING WEST. - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  8. Circle Time: An Exploratory Study of Activities and Challenging Behavior in Head Start Classrooms

    ERIC Educational Resources Information Center

    Zaghlawan, Hasan Y.; Ostrosky, Michaelene M.

    2011-01-01

    The purpose of this descriptive study was to examine circle time activities in eight Head Start classrooms. A total of 7 h of observations occurred in eight classrooms. Songs and academic activities were the most frequently occurring activities. Challenging behavior during circle time also was examined. The three activities with the highest…

  9. Young Puerto Rican Children's Exploration of Racial Discourses within the Figured Worlds of Literature Circles

    ERIC Educational Resources Information Center

    Castrodad-Rodriguez, Patricia Margarita

    2010-01-01

    This study examines the racial discourses of six and seven year old Puerto Rican children participating in small group literature circles over one academic year. The main research question is "How do Puerto Rican young children in a multiage classroom construct race through dialogue within the figured worlds of literature circles?" This study…

  10. Health Literacy Study Circles[superscript +]. Introduction: Overview, Planning, and Facilitation Tips

    ERIC Educational Resources Information Center

    Rudd, Rima; Soricone, Lisa; Santos, Maricel; Zobel, Emily; Smith, Janet

    2005-01-01

    A Health Literacy Study Circle[superscript +] is a multi-session professional development activity for adult education practitioners, conducted by a facilitator. All the information and materials required to conduct each Health Literacy Study Circle[superscript +] is presented in two parts: this Introduction and the "Facilitator's Guide" for each…

  11. Hough-transform-based circle detection using an array of multimode optical fibers

    NASA Astrophysics Data System (ADS)

    Li, Yao; Eichmann, George

    1987-02-01

    The generation of an optical Hough transform (OHT) to detect a circle is proposed. The method is based on the use of a 2D multimode step-index optical fiber array. Both the position and radius of a circle can be detected. Some of the OHT performance parameters are also discussed.

  12. "Ownership" of English in the Outer Circle: An Alternative to the NS-NNS Dichotomy

    ERIC Educational Resources Information Center

    Higgins, Christina

    2003-01-01

    The linguistic classification of English speakers from outer-circle countries, such as India, Malaysia, and Singapore, is often ambiguous because the Englishes they speak are considered different from interlanguages yet are not considered native varieties. This study investigates whether outer-circle speakers can be viewed as equivalent to…

  13. Dynamic Investigation of Triangles Inscribed in a Circle, Which Tend to an Equilateral Triangle

    ERIC Educational Resources Information Center

    Stupel, Moshe; Oxman, Victor; Sigler, Avi

    2017-01-01

    We present a geometrical investigation of the process of creating an infinite sequence of triangles inscribed in a circle, whose areas, perimeters and lengths of radii of the inscribed circles tend to a limit in a monotonous manner. First, using geometrical software, we investigate four theorems that represent interesting geometrical properties,…

  14. How Many Times Does a Radius Square Fit into the Circle?

    ERIC Educational Resources Information Center

    Flores, Alfinio; Regis, Troy P.

    2003-01-01

    Illustrates a way in which students can estimate the ratio of an area of a circle using the radius square. Discusses why the same value of pi appears in both the formulas for the circumference and the area of the circle. (YDS)

  15. Comparing Interactions in Literature Circles in Both Online and in Class Discussions

    ERIC Educational Resources Information Center

    Skeen, Christel Ghrist

    2014-01-01

    Discourse analysis of literature circles can lead educators to understand the different types of interactions taking place as students talk about text. Social and academic interactions exist in both face-to-face and online discussions of reading material. This study examines two different settings of literature circles and compares interactions of…

  16. The Use of Quality Circle Techniques To Improve Problem Solving in Elementary School.

    ERIC Educational Resources Information Center

    De Candido, Linda S.

    A sequentially planned program using quality circle techniques was adapted for the educational environment and Implemented in an elementary school in central Florida. The program consisted of 10 sessions designed to acquaint team leaders and administrators with the quality circle techniques and, under the direction of a trained facilitator, to…

  17. Three Keys for Successful Circle Time: Responding to Children with Diverse Abilities.

    ERIC Educational Resources Information Center

    Wald, Penelope J.; And Others

    This article presents strategies that promote responsive instruction of young children with diverse abilities during teacher-directed large group times, specifically "circle time." It uses a traditional circle time format to show how such typical activities as observing the weather can be modified to provide multisensory, multilevel, and…

  18. The Revival of Research Circles: Meeting the Needs of Modern Aging and the Third Age

    ERIC Educational Resources Information Center

    Ostlund, Britt

    2008-01-01

    This article provides evidence that it is worthwhile to reconsider the traditional research circle method as a means of involving people in the third age in fulfilling their needs to participate in learning activities and make their voices heard. The findings are based on three cases of research circles consistently driven by the interests of the…

  19. Analysis of Student Responses to Participation in Literature Circles in a University Classroom

    ERIC Educational Resources Information Center

    Randall, Lynda E.; DeCastro-Ambrosetti, Debra

    2009-01-01

    This combined quantitative and qualitative study examined the responses of students to participation in literature circles and the use of trade books in a university classroom. Students in an adolescence course participated in this strategy throughout the semester. The literature circles involved small groups of students who had chosen to read the…

  20. Circle Time: An Exploratory Study of Activities and Challenging Behavior in Head Start Classrooms

    ERIC Educational Resources Information Center

    Zaghlawan, Hasan Y.; Ostrosky, Michaelene M.

    2011-01-01

    The purpose of this descriptive study was to examine circle time activities in eight Head Start classrooms. A total of 7 h of observations occurred in eight classrooms. Songs and academic activities were the most frequently occurring activities. Challenging behavior during circle time also was examined. The three activities with the highest…

  1. Providing a Full Circle of Support to Teachers in an Inclusive Elementary School

    ERIC Educational Resources Information Center

    Waldron, Nancy L.; Redd, Lacy

    2011-01-01

    Providing a full circle of support to teachers in an inclusive elementary school, the Newberry Elementary School (NES) principal and staff have worked for 5 years to ensure the inclusion of students with disabilities in general education classrooms. The authors would like to share their perceptions of how this full circle (the multiple systems) of…

  2. A Historical Note on the Proof of the Area of a Circle

    ERIC Educational Resources Information Center

    Wilamowsky, Yonah; Epstein, Sheldon; Dickman, Bernard

    2011-01-01

    Proofs that the area of a circle is nr[superscript 2] can be found in mathematical literature dating as far back as the time of the Greeks. The early proofs, e.g. Archimedes, involved dividing the circle into wedges and then fitting the wedges together in a way to approximate a rectangle. Later more sophisticated proofs relied on arguments…

  3. Report of a Study of the Pacific Circle Consortium. [Final Report].

    ERIC Educational Resources Information Center

    Kemmis, Stephen

    A five-part cumulative report details the activities of the Pacific Circle Consortium. Section 1, on the origins of the Pacific Circle, describes the consortium on three levels: participating organization of Economic Cooperation and Development (OECD) countries, participating institutions, and development teams. In section 2, the involvement of…

  4. We Can All Participate! Adapting Circle Time for Children with Autism

    ERIC Educational Resources Information Center

    Barton, Erin E.; Reichow, Brian; Wolery, Mark; Chen, Ching-I

    2011-01-01

    This article describes a set of strategies for including children with autism in circle time. Successful inclusion involves careful planning, collaboration, and consideration of individual needs. Circle time can be a positive activity for children with autism when individual needs and strengths are considered. Environmental modifications and…

  5. Learning Circles: One Form of Knowledge Production in Social Action Research

    ERIC Educational Resources Information Center

    Ravensbergen, Frances; Vanderplaat, Madine

    2010-01-01

    This paper explores the use of "learning circles" as one form of knowledge production in social action research. It reports on a project that used learning circles as a setting within which to increase the engagement of people living with low income in developing strategies for the reduction and elimination of poverty in Canada. It…

  6. Collaborative Inquiry in Reading Recovery, or "Why Sit in a Circle?"

    ERIC Educational Resources Information Center

    Rodgers, Emily

    2000-01-01

    In Reading Recovery, training participants sit in a circle to discuss lessons that have been communally observed. The rationale for sitting in a circle without a table for discussion can be better understood by considering these two ideas: (1) the role of language in learning; and (2) the way conversation is affected by the physical positioning of…

  7. Laying the Groundwork for the Effective Implementation of Quality Circles in a Community College.

    ERIC Educational Resources Information Center

    Ruff, Dan

    This five-part paper provides an overview of the use of quality circles as a participative management technique in community colleges. Section I offers an introduction to the technique, reviewing the history of quality circles from their development in Japan in the early 1960s to their introduction in American higher education in the early 1980s.…

  8. Seeds of Change: Using Peacemaking Circles to Build a Village for Every Child

    ERIC Educational Resources Information Center

    Boyes-Watson, Carolyn

    2005-01-01

    Roca, Inc., a grassroots human development and community organization, has adopted the peacemaking circle as a tool in its relationship building with youth, communities, and formal systems. Circles are a method of communication derived from aboriginal and native traditions. In Massachusetts, the Department of Social Services and the Department of…

  9. A Historical Note on the Proof of the Area of a Circle

    ERIC Educational Resources Information Center

    Wilamowsky, Yonah; Epstein, Sheldon; Dickman, Bernard

    2011-01-01

    Proofs that the area of a circle is nr[superscript 2] can be found in mathematical literature dating as far back as the time of the Greeks. The early proofs, e.g. Archimedes, involved dividing the circle into wedges and then fitting the wedges together in a way to approximate a rectangle. Later more sophisticated proofs relied on arguments…

  10. Dynamic Investigation of Triangles Inscribed in a Circle, Which Tend to an Equilateral Triangle

    ERIC Educational Resources Information Center

    Stupel, Moshe; Oxman, Victor; Sigler, Avi

    2017-01-01

    We present a geometrical investigation of the process of creating an infinite sequence of triangles inscribed in a circle, whose areas, perimeters and lengths of radii of the inscribed circles tend to a limit in a monotonous manner. First, using geometrical software, we investigate four theorems that represent interesting geometrical properties,…

  11. Circle communication: an old form of communication useful for 21st century leadership.

    PubMed

    Michaels, Cathleen L

    2002-01-01

    Circle communication is a form of group exchange that builds a network of relationships, a sense of community. Through practices of active listening, intentional speaking, and conscious self-monitoring, circle communication emphasizes individual contribution while building consensus to fulfill the purpose of the group. In this regard, circle communication supports a shared leadership in which all individual and unique perspectives are engaged to create the common ground for action. Circle communication emerges from a shared humanity, which can balance the "division of labor" and people only being known by their specific organizational roles. Both are needed to sustain an organization. By nurturing the human side, regardless of role and function, circle communication intersects with diversity or the uniqueness of each individual, storytelling, coaching, guiding, and mentoring, as well as discovering and responding to conflict.

  12. A new method for fast circle detection in a complex background image

    NASA Astrophysics Data System (ADS)

    Wu, Meijun; Yang, Jie; Sun, Yadong

    2011-11-01

    A new method for circle detection, Hough gradient clustering method, has been developed in this paper. By using gradient direction angle to find the diameter of a circle, the new method can rapidly detect the circle in a complex background. The crucial steps in this method are the feature extraction and the clustering of the points which have the same gray direction angle and are collinear along the gradient direction. The application of the two-to-one space mapping and 1-2Hough transform can further reduce the useless calculation in the process of circle detection. Comparing with the Hough gradient method in OpenCV, the newly developed method shows a higher efficiency of circle detection in a complex background image as well as a great improvement in the anti-noise ability.

  13. Monte Carlo method based radiative transfer simulation of stochastic open forest generated by circle packing application

    NASA Astrophysics Data System (ADS)

    Jin, Shengye; Tamura, Masayuki

    2013-10-01

    Monte Carlo Ray Tracing (MCRT) method is a versatile application for simulating radiative transfer regime of the Solar - Atmosphere - Landscape system. Moreover, it can be used to compute the radiation distribution over a complex landscape configuration, as an example like a forest area. Due to its robustness to the complexity of the 3-D scene altering, MCRT method is also employed for simulating canopy radiative transfer regime as the validation source of other radiative transfer models. In MCRT modeling within vegetation, one basic step is the canopy scene set up. 3-D scanning application was used for representing canopy structure as accurately as possible, but it is time consuming. Botanical growth function can be used to model the single tree growth, but cannot be used to express the impaction among trees. L-System is also a functional controlled tree growth simulation model, but it costs large computing memory. Additionally, it only models the current tree patterns rather than tree growth during we simulate the radiative transfer regime. Therefore, it is much more constructive to use regular solid pattern like ellipsoidal, cone, cylinder etc. to indicate single canopy. Considering the allelopathy phenomenon in some open forest optical images, each tree in its own `domain' repels other trees. According to this assumption a stochastic circle packing algorithm is developed to generate the 3-D canopy scene in this study. The canopy coverage (%) and the tree amount (N) of the 3-D scene are declared at first, similar to the random open forest image. Accordingly, we randomly generate each canopy radius (rc). Then we set the circle central coordinate on XY-plane as well as to keep circles separate from each other by the circle packing algorithm. To model the individual tree, we employ the Ishikawa's tree growth regressive model to set the tree parameters including DBH (dt), tree height (H). However, the relationship between canopy height (Hc) and trunk height (Ht) is

  14. A Comprehensive Study of the Anatomical Variations of the Circle of Willis in Adult Human Brains

    PubMed Central

    Iqbal, S.

    2013-01-01

    Background: Cerebrovascular diseases such as stroke, aneurysms and arterio-venous malformations are very much prevalent in our country. Circle of Willis, as an anastomotic polygon at the base of the brain forms an important collateral network to maintain adequate cerebral perfusion. Changes in the normal morphology of the circle may condition the appearance and severity of symptoms of cerebrovascular disorders, such as aneurysms, infarctions and other vascular anomalies. A possible link between abnormalities of the circle of Willis and the mentally ill patients has been observed. Aim and Objectives: The aim of the present study is to have an intimate knowledge of the variations in the cerebral arterial circle and to clarify the clinical importance of these variations in certain forms of cerebrovascular diseases. So an attempt was made to analyse the anatomical variations of the circle in a random population. Material and Methods: The work was based on fifty adult brains from persons died of diverse causes. The materials were obtained during routine autopsy studies. The base of the brain including the brain stem with intact arterial circle was preserved in 10% formalin for 10 days. The circle of Willis and its major branches were carefully dissected under water using a magnifying lens. The variations were recorded and photographed. Results: Majority of the circles (52%) showed anomalies. Hypoplasia was the most frequent anomaly and was found in 24% of the brains. Accessory vessels in the form of duplications/triplications of anterior communicating artery were seen in 12% of the circles. The embryonic origin of the posterior cerebral artery from the internal carotid persisted in 10% of the circles. An incomplete circle due to the absence of one or other posterior communicating artery was found in 6% of the specimens.Variations are more frequent in posterior half of the circle. Conclusion: The anatomical variations of the circle of Willis were probably genetically

  15. A comprehensive study of the anatomical variations of the circle of willis in adult human brains.

    PubMed

    Iqbal, S

    2013-11-01

    Cerebrovascular diseases such as stroke, aneurysms and arterio-venous malformations are very much prevalent in our country. Circle of Willis, as an anastomotic polygon at the base of the brain forms an important collateral network to maintain adequate cerebral perfusion. Changes in the normal morphology of the circle may condition the appearance and severity of symptoms of cerebrovascular disorders, such as aneurysms, infarctions and other vascular anomalies. A possible link between abnormalities of the circle of Willis and the mentally ill patients has been observed. The aim of the present study is to have an intimate knowledge of the variations in the cerebral arterial circle and to clarify the clinical importance of these variations in certain forms of cerebrovascular diseases. So an attempt was made to analyse the anatomical variations of the circle in a random population. The work was based on fifty adult brains from persons died of diverse causes. The materials were obtained during routine autopsy studies. The base of the brain including the brain stem with intact arterial circle was preserved in 10% formalin for 10 days. The circle of Willis and its major branches were carefully dissected under water using a magnifying lens. The variations were recorded and photographed. Majority of the circles (52%) showed anomalies. Hypoplasia was the most frequent anomaly and was found in 24% of the brains. Accessory vessels in the form of duplications/triplications of anterior communicating artery were seen in 12% of the circles. The embryonic origin of the posterior cerebral artery from the internal carotid persisted in 10% of the circles. An incomplete circle due to the absence of one or other posterior communicating artery was found in 6% of the specimens.Variations are more frequent in posterior half of the circle. The anatomical variations of the circle of Willis were probably genetically determined, develop in early embryonic stage and persist in post natal life

  16. Localized vegetation patterns, fairy circles, and localized patches in arid landscapes

    NASA Astrophysics Data System (ADS)

    Escaff, D.; Fernandez-Oto, C.; Clerc, M. G.; Tlidi, M.

    2015-02-01

    We investigate the formation of localized structures with varying widths in one- and two-dimensional systems. The mechanism of stabilization is attributed to strongly nonlocal coupling mediated by a Lorentzian type of kernel. We show that, in addition to stable dips found recently [see, e.g. Fernandez-Oto et al., Phys. Rev. Lett. 110, 174101 (2013), 10.1103/PhysRevLett.110.174101], there are stable localized peaks which appear as a result of strongly nonlocal coupling. We applied this mechanism to arid ecosystems by considering a prototype model of a Nagumo type. In one dimension, we study the front connecting the stable uniformly vegetated state to the bare one under the effect of strongly nonlocal coupling. We show that strongly nonlocal coupling stabilizes both—dip and peak—localized structures. We show analytically and numerically that the width of a localized structure, which we interpret as a fairy circle, increases strongly with the aridity parameter. This prediction is in agreement with published observations. In addition, we predict that the width of localized patch decreases with the degree of aridity. Numerical results are in close agreement with analytical predictions.

  17. ULYSSES comes full circle, before revisiting the Sun's poles

    NASA Astrophysics Data System (ADS)

    1998-04-01

    From its unique perspective, Ulysses has provided scientists with the very first all-round map of the heliosphere, the huge bubble in space filled by the Sun's wind. The Earth swims deep inside the heliosphere, and gusts and shocks in the solar wind can harm satellites, power supplies and ommunications. They may also affect our planet's weather. A better grasp of the solar weather in the heliosphere is therefore one of the major aims of ESA's science programme. In a project of international cooperation between ESA and NASA, Ulysses was launched towards Jupiter in October 1990 by the US space shuttle Discovery. Arriving in February 1992, Ulysses stole energy from the giant planet in a slingshot manoeuvre and was propelled back towards the Sun in an elongated orbit almost at right angles to the ecliptic plane, where the Earth and other planets circle the Sun. "This month Ulysses returns to the point in space where its out-of-ecliptic journey began, but Jupiter isn't there," explains Richard Marsden, ESA's project scientist for Ulysses. "Following its own inexorable path around the Sun, Jupiter is far away on the opposite side of the Solar System. So Ulysses' course will not be changed a second time. The spacecraft is now in effect a man-made comet, forever bound into a 6-year polar orbit around the Sun." Ulysses now starts its second orbit. It will travel over the poles of the Sun in 2000-2001 just as the count of dark sunspots is expected to reach a maximum. With its operational life extended for the Ulysses Solar Maximum Mission, the spacecraft will find the heliosphere much stormier than during its first orbit. Discoveries so far Like its mythical namesake, Ulysses has already had an eventful voyage of discovery. Its unique trajectory has provided the scientific teams with a new perspective, from far out in space and especially in the previously unknown regions of the heliosphere over the Sun's poles. Passing within 9.8 degrees of the polar axis, the highly

  18. "Quality Circles": A Strategy for Personal and Curriculum Development. Coombe Lodge Working Paper. Information Bank Number 1803.

    ERIC Educational Resources Information Center

    Field, M. J.; Harrison, A. B.

    Quality circles attempt to satisfy both task and personal needs through staff involvement in solving work-related problems. This paper summarizes quality circle theory, applies it to school settings, and suggests a framework for introducing the process to educational institutions. After briefly defining quality circles, the article presents two…

  19. Modelling of the toe trajectory during normal gait using circle-fit approximation.

    PubMed

    Fang, Juan; Hunt, Kenneth J; Xie, Le; Yang, Guo-Yuan

    2016-10-01

    This work aimed to validate the approach of using a circle to fit the toe trajectory relative to the hip and to investigate linear regression models for describing such toe trajectories from normal gait. Twenty-four subjects walked at seven speeds. Best-fit circle algorithms were developed to approximate the relative toe trajectory using a circle. It was detected that the mean approximation error between the toe trajectory and its best-fit circle was less than 4 %. Regarding the best-fit circles for the toe trajectories from all subjects, the normalised radius was constant, while the normalised centre offset reduced when the walking cadence increased; the curve range generally had a positive linear relationship with the walking cadence. The regression functions of the circle radius, the centre offset and the curve range with leg length and walking cadence were definitively defined. This study demonstrated that circle-fit approximation of the relative toe trajectories is generally applicable in normal gait. The functions provided a quantitative description of the relative toe trajectories. These results have potential application for design of gait rehabilitation technologies.

  20. Kinetics of the forelimb in horses circling on different ground surfaces at the trot.

    PubMed

    Chateau, Henry; Camus, Mathieu; Holden-Douilly, Laurène; Falala, Sylvain; Ravary, Bérangère; Vergari, Claudio; Lepley, Justine; Denoix, Jean-Marie; Pourcelot, Philippe; Crevier-Denoix, Nathalie

    2013-12-01

    Circling increases the expression of distal forelimb lameness in the horse, depending on rein, diameter and surface properties of the circle. However, there is limited information about the kinetics of horses trotting on circles. The aim of this study was to quantify ground reaction force (GRF) and moments in the inside and outside forelimb of horses trotting on circles and to compare the results obtained on different ground surfaces. The right front hoof of six horses was equipped with a dynamometric horseshoe, allowing the measurement of 3-dimensional GRF, moments and trajectory of the centre of pressure. The horses were lunged at slow trot (3 m/s) on right and left 4 m radius circles on asphalt and on a fibre sand surface. During circling, the inside forelimb produced a smaller peak vertical force and the stance phase was longer in comparison with the outside forelimb. Both right and left circling produced a substantial transversal force directed outwards. On a soft surface (sand fibre), the peak transversal force and moments around the longitudinal and vertical axes of the hoof were significantly decreased in comparison with a hard surface (asphalt). Sinking of the lateral or medial part of the hoof in a more compliant surface enables reallocation of part of the transversal force into a proximo-distal force, aligned with the limb axis, thus limiting extrasagittal stress on the joints.