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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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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…

  16. 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.

  17. 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.

  18. 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.

  19. 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)

  20. 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

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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…

  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. 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

  14. 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

  15. 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

  16. 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.

  17. 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

  18. 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.

  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. 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…

  1. 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…

  2. 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…

  3. 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…

  4. 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…

  5. 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…

  6. 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)

  7. 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…

  8. 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

  9. 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.

  10. 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…

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. 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

  16. [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.

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

    PubMed

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

    2016-11-15

    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.

  18. 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

  19. 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.

  20. 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…

  1. 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

  2. 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

  3. 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…

  4. 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.

  5. 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…

  6. 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.

  7. 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…

  8. 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)

  9. 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…

  10. 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…

  11. 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)

  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. 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…

  14. 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

  15. 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.

  16. 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…

  17. 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

  18. 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

  19. 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)…

  20. 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.

  1. 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)

  2. 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…

  3. 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.

  4. 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…

  5. 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;…

  6. 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…

  7. 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…

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  9. 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

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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).

  16. 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.

  17. 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.

  18. 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

  19. [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.

  20. 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,…

  1. 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.

  2. 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

  3. 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.

  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. 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…

  6. 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…

  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. Gradual regime shifts in fairy circles

    PubMed Central

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

    2015-01-01

    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. PMID:26362787

  9. 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.

  10. 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…

  11. 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…

  12. 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…

  13. 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…

  14. 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,…

  15. 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)

  16. 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…

  17. 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…

  18. 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…

  19. 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…

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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…

  7. 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…

  8. 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…

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  19. 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,…

  20. 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…

  1. 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.

  2. 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.

  3. 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.

  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. 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…

  7. 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…

  8. 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…

  9. D'Nealian Handwriting versus Circle-Stick Print.

    ERIC Educational Resources Information Center

    Thurber, Donald N.

    This paper argues against teaching children to make letters using circle-stick writing. It contends that the circle-stick method requires continued pen/pencil lifts hindering rhythm or flow in the writing process and that there is little carry-over value into cursive writing as the two scripts are totally different. D'Nealian print, one type of…

  10. 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…

  11. 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…

  12. 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…

  13. 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…

  14. 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,…

  15. 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…

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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.

  8. 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’.

  9. 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

  10. 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

  11. 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.

  12. 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)

  13. 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

  14. 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

  15. 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

  16. 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.

  17. 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.

  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. 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.

  20. 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.

  1. 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.

  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. 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…

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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…

  14. 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…

  15. 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…

  16. 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…

  17. 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…

  18. 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…

  19. 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…

  20. 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…

  1. 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"…

  2. 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…

  3. 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…

  4. 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,…

  5. 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,…

  6. 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)

  7. 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…

  8. 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)

  9. The Circle of Courage and Erikson's Psychological Stages.

    ERIC Educational Resources Information Center

    Coughlan, Felicity; Welsh-Breetzke, Andrea

    2002-01-01

    Describes the application of positive youth development principles to challenges faced by adolescent females in South Africa. A mainline, Euro-centric theory, Erikson's life stages (1963), is compared with the Circle of Courage model based on Native American Tribal wisdom. The differences and correlation in these approaches are explored through…

  10. 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

  11. 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

  12. 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)

  13. 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…

  14. 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…

  15. 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…

  16. 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…

  17. 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…

  18. 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…

  19. 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…

  20. 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

  1. 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…

  2. 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

  3. 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.

  4. "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.

  5. 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

  6. 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

  7. 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…

  8. 78 FR 9910 - Circle Environmental #1 and #2 Sites; Dawson, Terrell County, GA; Notice of Settlement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-12

    .... Submit your comments by Site name Circle Environmental 1 and 2 Site by one of the following methods: www... AGENCY Circle Environmental 1 and 2 Sites; Dawson, Terrell County, GA; Notice of Settlement AGENCY... removal action at the Circle Environmental 1 and 2 Superfund Sites located in Dawson, Terrell...

  9. 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.

  10. 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…

  11. 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...

  12. 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,…

  13. 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,…

  14. 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…

  15. 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.

  16. 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.

  17. 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.

  18. 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

  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. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  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. 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…

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  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. 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

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. [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.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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…

  17. 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,…

  18. 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…

  19. 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…

  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. 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…

  2. 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…

  3. 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…

  4. 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…

  5. 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.…

  6. 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)

  7. 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…

  8. 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…

  9. 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…

  10. 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

  11. 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…

  12. 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…

  13. 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.

  14. 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…

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 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

  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.

  1. Using great circles to understand motion on a rotating sphere

    NASA Astrophysics Data System (ADS)

    McIntyre, D. H.

    2000-12-01

    Motion observed in a rotating frame of reference is generally explained by invoking inertial forces. While this approach simplifies some problems, there is often little physical insight into the motion, in particular into the effects of the Coriolis force. To aid in the understanding of three-dimensional inertial forces, motion on a rotating sphere is considered from the points of view of an inertial observer and of an observer fixed on the sphere. The inertial observer observes the motion to be along a great circle fixed in the inertial frame, in analogy with simple straight-line motion in the two-dimensional case. This simple "straight-line" viewpoint of the inertial observer is reconciled qualitatively and quantitatively with the view of the rotating observer that requires inertial forces in order to account for the motion. Through a succession of simple examples, the Coriolis and centrifugal effects are isolated and illustrated, as well as effects due to the curvilinear nature of motion on a sphere.

  2. Gold Nanowire Based Electrical DNA Detection Using Rolling Circle Amplification

    PubMed Central

    2014-01-01

    We present an electrical sensor that uses rolling circle amplification (RCA) of DNA to stretch across the gap between two electrodes, interact with metal nanoparticle seeds to generate an electrically conductive nanowire, and produce electrical signals upon detection of specific target DNA sequences. RCA is a highly specific molecular detection mechanism based on DNA probe circularization. With this technique, long single-stranded DNA with simple repetitive sequences are produced. Here we show that stretched RCA products can be metalized using silver or gold solutions to form metal wires. Upon metallization, the resistance drops from TΩ to kΩ for silver and to Ω for gold. Metallization is seeded by gold nanoparticles aligned along the single-stranded DNA product through hybridization of functionalized oligonucleotides. We show that combining RCA with electrical DNA detection produces results in readout with very high signal-to-noise ratio, an essential feature for sensitive and specific detection assays. Finally, we demonstrate detection of 10 ng of Escherichia coli genomic DNA using the sensor concept. PMID:24433087

  3. Hypomagnesemia in Type 2 Diabetes: A Vicious Circle?

    PubMed

    Gommers, Lisanne M M; Hoenderop, Joost G J; Bindels, René J M; de Baaij, Jeroen H F

    2016-01-01

    Over the past decades, hypomagnesemia (serum Mg(2+) <0.7 mmol/L) has been strongly associated with type 2 diabetes mellitus (T2DM). Patients with hypomagnesemia show a more rapid disease progression and have an increased risk for diabetes complications. Clinical studies demonstrate that T2DM patients with hypomagnesemia have reduced pancreatic β-cell activity and are more insulin resistant. Moreover, dietary Mg(2+) supplementation for patients with T2DM improves glucose metabolism and insulin sensitivity. Intracellular Mg(2+) regulates glucokinase, KATP channels, and L-type Ca(2+) channels in pancreatic β-cells, preceding insulin secretion. Moreover, insulin receptor autophosphorylation is dependent on intracellular Mg(2+) concentrations, making Mg(2+) a direct factor in the development of insulin resistance. Conversely, insulin is an important regulator of Mg(2+) homeostasis. In the kidney, insulin activates the renal Mg(2+) channel transient receptor potential melastatin type 6 that determines the final urinary Mg(2+) excretion. Consequently, patients with T2DM and hypomagnesemia enter a vicious circle in which hypomagnesemia causes insulin resistance and insulin resistance reduces serum Mg(2+) concentrations. This Perspective provides a systematic overview of the molecular mechanisms underlying the effects of Mg(2+) on insulin secretion and insulin signaling. In addition to providing a review of current knowledge, we provide novel directions for future research and identify previously neglected contributors to hypomagnesemia in T2DM.

  4. BLOOD FLOW IN THE CIRCLE OF WILLIS: MODELING AND CALIBRATION*

    PubMed Central

    DEVAULT, KRISTEN; GREMAUD, PIERRE A.; NOVAK, VERA; OLUFSEN, METTE S.; VERNIÈRES, GUILLAUME; ZHAO, PENG

    2008-01-01

    A numerical model based on one-dimensional balance laws and ad hoc zero-dimensional boundary conditions is tested against experimental data. The study concentrates on the circle of Willis, a vital subnetwork of the cerebral vasculature. The main goal is to obtain efficient and reliable numerical tools with predictive capabilities. The flow is assumed to obey the Navier–Stokes equations, while the mechanical reactions of the arterial walls follow a viscoelastic model. Like many previous studies, a dimension reduction is performed through averaging. Unlike most previous work, the resulting model is both calibrated and validated against in vivo data, more precisely transcranial Doppler data of cerebral blood velocity. The network considered has three inflow vessels and six outflow vessels. Inflow conditions come from the data, while outflow conditions are modeled. Parameters in the outflow conditions are calibrated using a subset of the data through ensemble Kalman filtering techniques. The rest of the data is used for validation. The results demonstrate the viability of the proposed approach. PMID:19043621

  5. Poor condition and infection: a vicious circle in natural populations.

    PubMed

    Beldomenico, Pablo M; Telfer, Sandra; Gebert, Stephanie; Lukomski, Lukasz; Bennett, Malcolm; Begon, Michael

    2008-08-07

    Pathogens may be important for host population dynamics, as they can be a proximate cause of morbidity and mortality. Infection dynamics, in turn, may be dependent on the underlying condition of hosts. There is a clear potential for synergy between infection and condition: poor condition predisposes to host infections, which further reduce condition and so on. To provide empirical data that support this notion, we measured haematological indicators of infection (neutrophils and monocytes) and condition (red blood cells (RBCs) and lymphocytes) in field voles from three populations sampled monthly for 2 years. Mixed-effect models were developed to evaluate two hypotheses, (i) that individuals with low lymphocyte and/or RBC levels are more prone to show elevated haematological indicators of infection when re-sampled four weeks later, and (ii) that a decline in indicators of condition is likely to follow the development of monocytosis or neutrophilia. We found that individuals with low RBC and lymphocyte counts had increased probabilities of developing monocytosis and higher increments in neutrophils, and that high indices of infection (neutrophilia and monocytosis) were generally followed by a declining tendency in the indicators of condition (RBCs and lymphocytes). The vicious circle that these results describe suggests that while pathogens overall may be more important in wildlife dynamics than has previously been appreciated, specific pathogens are likely to play their part as elements of an interactive web rather than independent entities.

  6. Poor condition and infection: a vicious circle in natural populations

    PubMed Central

    Beldomenico, Pablo M; Telfer, Sandra; Gebert, Stephanie; Lukomski, Lukasz; Bennett, Malcolm; Begon, Michael

    2008-01-01

    Pathogens may be important for host population dynamics, as they can be a proximate cause of morbidity and mortality. Infection dynamics, in turn, may be dependent on the underlying condition of hosts. There is a clear potential for synergy between infection and condition: poor condition predisposes to host infections, which further reduce condition and so on. To provide empirical data that support this notion, we measured haematological indicators of infection (neutrophils and monocytes) and condition (red blood cells (RBCs) and lymphocytes) in field voles from three populations sampled monthly for 2 years. Mixed-effect models were developed to evaluate two hypotheses, (i) that individuals with low lymphocyte and/or RBC levels are more prone to show elevated haematological indicators of infection when re-sampled four weeks later, and (ii) that a decline in indicators of condition is likely to follow the development of monocytosis or neutrophilia. We found that individuals with low RBC and lymphocyte counts had increased probabilities of developing monocytosis and higher increments in neutrophils, and that high indices of infection (neutrophilia and monocytosis) were generally followed by a declining tendency in the indicators of condition (RBCs and lymphocytes). The vicious circle that these results describe suggests that while pathogens overall may be more important in wildlife dynamics than has previously been appreciated, specific pathogens are likely to play their part as elements of an interactive web rather than independent entities. PMID:18448414

  7. Circle diagram approach for self excited induction generators

    SciTech Connect

    Muljadi, E.; Carlin, P.W.; Osgood, R.M.

    1993-05-01

    When an induction generator is connected to a utility line supply, the voltage and frequency at the terminal output are the same as the voltage and frequency of the utility line supply to which the generator is connected. The reactive power needed by the induction generator is supplied by the utility and the real power is returned to the utility. With a fixed frequency dictated by the utility, the induction machine starts generating above the synchronous speed. The range of speed is also limited by the slip. At a very high slip, the copper losses increases as the current increases. On the other hand, in an isolated operation, the induction generator operates in self-excitation mode. It determines its own voltage and frequency. These two quantities depend on the size of the AC capacitor, the induction machine parameters, the electrical load, and the speed of the generator. The operating speed of the induction generator is extended without generating excessive loss. This paper presents an analytical study by utilizing a circle diagram to illustrate the operation of the induction generator in isolated operation. The steady-state calculations are presented to support the analysis. Possible applications for the system in variable-speed generation are currently under investigation. The output can be directly connected to equipment that is non-sensitive to the frequency (a heater, battery charger, etc.) or can be connected to a converter to get a fixed-frequency AC output.

  8. The Children, Intimate Relationships, and Conflictual Life Events (CIRCLE) Interview for Simultaneous Measurement of Intimate Partner and Parent to Child Aggression.

    PubMed

    Marshall, Amy D; Feinberg, Mark E; Jones, Damon E; Chote, Daniel R

    2016-09-19

    Despite substantial rates of parent to child aggression (PCA) and intimate partner aggression (IPA) co-occurrence within families, the co-occurrence of PCA and IPA within incidents of aggression has not previously been examined. To do so, we developed the Children, Intimate Relationships, and Conflictual Life Events (CIRCLE) interview to simultaneously measure incidents of psychological and physical PCA and IPA. The CIRCLE interview was administered quarterly for approximately 1 year to 109 women and 94 men from 111 couples with a first born child approximately 32 months of age at study initiation. Demonstrating the CIRCLE interview's ability to yield new knowledge about the nature of family aggression, we describe the frequency of aggressive incidents, the average number of aggressive behaviors within incidents, the daily occurrence of multiple aggressive incidents, and rates of within-incident PCA and IPA co-occurrence. With the exception of men's physical IPA, aggression scores derived from the CIRCLE interview exhibited a relatively high degree of interpartner reporting concordance, as well as structural validity and convergent validity with common aggression measures. Aggression reports via repeated testing were not influenced by social desirability or attempts to avoid aggression. Participants who perceived enhanced memory for aggression as a function of study participation reported increasing PCA and IPA frequencies over time. In the prediction of child conduct and emotional problems, the CIRCLE interview demonstrated predictive validity and incremental validity over traditional aggression measures. For the first time, within-incident co-occurrence of PCA and IPA was documented and shown to uniquely impact child outcomes. (PsycINFO Database Record

  9. Constructing knowledge about the trigonometric functions and their geometric meaning on the unit circle

    NASA Astrophysics Data System (ADS)

    Altman, Renana; Kidron, Ivy

    2016-10-01

    Processes of knowledge construction are investigated. A learner is constructing knowledge about the trigonometric functions and their geometric meaning on the unit circle. The analysis is based on the dynamically nested epistemic action model for abstraction in context. Different tasks are offered to the learner. In his effort to perform the different tasks, he has the opportunity to understand the process used to create unit circle representations of trigonometric expressions. The theoretical framework of abstraction in context is used to analyse the evolution of the learner's construction of knowledge in the transition from 'triangle' trigonometry to 'circle' trigonometry.

  10. Off-great-circle paths in transequatorial propagation: 1. Discrete and diffuse types

    NASA Astrophysics Data System (ADS)

    Tsunoda, Roland T.; Maruyama, Takashi; Tsugawa, Takuya; Yokoyama, Tatsuhiro; Ishii, Mamoru; Nguyen, Trang T.; Ogawa, Tadahiko; Nishioka, Michi

    2016-11-01

    There is mounting evidence that plasma structure in nighttime equatorial F layer evolves from large-scale wave structure (LSWS) in the bottomside F layer. This process cannot be ignored because equatorial plasma bubbles (EPBs) arise from large-amplitude LSWS; and, because intense radiowave scintillations are associated with EPBs, understanding the LSWS-to-EPB process is a crucial step toward reliable Space Weather Forecasting. In this regard, the transequatorial propagation (TEP) experiment appears to be the most useful among available research instruments. After a lapse of 30 years, the TEP experiment has been resurrected; a goal of this research is to understand TEP measurements well enough so that they can be used to diagnose the LSWS-to-EPB process. Toward this end, new results are presented in two companion papers. Herein (P1), off-great-circle (OGC) propagation paths are shown to consist of two types, discrete and diffuse. The new findings include the following: (1) a generalized multireflection model that can explain most of the observed properties; (2) the discrete type is supported by multireflections from an unstructured upwelling, (3) the diffuse type is supported by reflections from plasma structure in EPBs; and (4) the observed east-west (EW) asymmetry can be explained in terms of a distorted upwelling or plasma structure along the west wall of an upwelling. In Paper 2 (P2), a second form of observed EW asymmetry is explained in terms of plasma structure, which is not aligned with the geomagnetic field. The findings strongly confirm a close relationship between upwellings, ESF patches, and OGC paths.

  11. DINE-1, the highest copy number repeats in Drosophila melanogaster are non-autonomous endonuclease-encoding rolling-circle transposable elements (Helentrons)

    PubMed Central

    2014-01-01

    Background The Drosophila INterspersed Elements-1 (DINE-1/INE1) transposable elements (TEs) are the most abundant component of the Drosophila melanogaster genome and have been associated with functional gene duplications. DINE-1 TEs do not encode any proteins (non-autonomous) thus are moved by autonomous partners. The identity of the autonomous partners has been a mystery. They have been allied to Helitrons (rolling-circle transposons), MITEs (DNA transposons), and non-LTR retrotransposons by different authors. Results We report multiple lines of bioinformatic evidence that illustrate the relationship of DINE-1 like TEs to endonuclease-encoding rolling-circle TEs (Helentrons). The structural features of Helentrons are described, which resemble the organization of the non-autonomous partners, but differ significantly from canonical Helitrons. In addition to the presence of an endonuclease domain fused to the Rep/Helicase protein, Helentrons have distinct structural features. Evidence is presented that illustrates that Helentrons are widely distributed in invertebrate, fish, and fungal genomes. We describe an intermediate family from the Phytophthora infestans genome that phylogenetically groups with Helentrons but that displays Helitron structure. In addition, evidence is presented that Helentrons can capture gene fragments in a pattern reminiscent of canonical Helitrons. Conclusions We illustrate the relationship of DINE-1 and related TE families to autonomous partners, the Helentrons. These findings will allow their proper classification and enable a more accurate understanding of the contribution of rolling-circle transposition to the birth of new genes, gene networks, and genome composition. PMID:24959209

  12. Vibration characteristic analysis method for the quartz microgyroscope based on the admittance circle

    NASA Astrophysics Data System (ADS)

    Wang, Haoxu; Dong, Peitao; Xie, Liqiang; Wu, Xuezhong

    2014-03-01

    The vibration characteristic analysis method for a quartz microgyroscope based on the admittance circle is reported in this paper. Admittance theory is introduced and the admittance circle principle is analysed to study the vibration characteristics of the quartz microgyroscope. The prototype gyroscope was fabricated by micro-electromechanical systems (MEMS) technology. The admittance and phase diagram of the work mode were obtained by vibration mode test systems. Then the admittance circle of the work mode was drawn, and the parameter identification of the transfer function between the voltage and current was completed to analyse the vibration characteristics. Therefore, the vibration characteristic analysis method based on the admittance circle can be used to build the transfer function of the quartz microgyroscope, which is helpful for the design of a high performance quartz microgyroscope.

  13. 78 FR 44119 - Circle Environmental #1 Superfund Site; Dawson, Terrell County, Georgia; Notice of Settlement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-23

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY Circle Environmental 1 Superfund Site; Dawson, Terrell County, Georgia; Notice of Settlement... Environmental 1 Superfund Site located in Dawson, Terrell County, Georgia. The settlement addresses...

  14. Visual Thinking, Algebraic Thinking, and a Full Unit-Circle Diagram.

    ERIC Educational Resources Information Center

    Shear, Jonathan

    1985-01-01

    The study of trigonometric functions in terms of the unit circle offer an example of how students can learn algebraic relations and operations while using visually oriented thinking. Illustrations are included. (MNS)

  15. DC66842 VIEW WEST FROM BANNEKER CIRCLE (RESERVATION NO. 719) TO ...

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

    DC-668-42 VIEW WEST FROM BANNEKER CIRCLE (RESERVATION NO. 719) TO THE DOME OF THE JEFFERSON MEMORIAL IN WEST POTOMAC PARK - L'Enfant-McMillan Plan of Washington, DC, Washington, District of Columbia, DC

  16. DC66820 VISTA EAST ALONG M STREET TO THOMAS CIRCLE FROM ...

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

    DC-668-20 VISTA EAST ALONG M STREET TO THOMAS CIRCLE FROM RESERVATION NO. 14 0 AT NEW HAMPSHIRE AVENUE AND 21ST STREET, NW - L'Enfant-McMillan Plan of Washington, DC, Washington, District of Columbia, DC

  17. SECTIONS B AND A FROM FLAGPOLE CIRCLE, WITH 28TH NEW ...

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

    SECTIONS B AND A FROM FLAGPOLE CIRCLE, WITH 28TH NEW YORK REGIMENT MONUMENT AT LEFT AND PENNSYLVANIA MONUMENT AT CENTER. VIEW TO NORTH. - Culpeper National Cemetery, 305 U.S. Avenue, Culpeper, Culpeper County, VA

  18. Generation of minimally persistent circle formation for a multi-agent system

    NASA Astrophysics Data System (ADS)

    Luo, Xiao-Yuan; Shao, Shi-Kai; Zhang, Yu-Yan; Li, Shao-Bao; Guan, Xin-Ping; Liu, Zhi-Xin

    2014-02-01

    In this paper, two methods of generating minimally persistent circle formation are presented. The proposed methods adopt a leader-follower strategy and all followers are firstly motivated to move into the leader's interaction range. Based on the information about relative angle and relative distance, two numbering schemes are proposed to generate minimally persistent circle formation. Distributed control laws are also designed to maintain the desired relative distance between agents. The distinctive features of the proposed methods are as follows. First, only 2n - 3 unilateral communication links for n agents are needed during the circle formation process and thus the communication complexity can be reduced. In addition, the formation topology is kept fixed for the whole motion and achieves a self-stability property. Finally, each follower keeps a regualr interval with its neighbors and the formation converges to a uniform circle formation. Simulation results are also provided to demonstrate the effectiveness of the proposed methods.

  19. Sister Circles as a Culturally Relevant Intervention for Anxious African American Women

    PubMed Central

    Neal-Barnett, Angela; Stadulis, Robert; Murray, Marsheena; Payne, Margaret Ralston; Thomas, Anisha; Salley, Bernadette B.

    2011-01-01

    Research on anxiety treatment with African American women reveals a need to develop interventions that address factors relevant to their lives. Such factors include feelings of isolation, multiple roles undertaken by Black women, and faith. A recurrent theme across treatment studies is the importance of having support from other Black women. Sister circles are support groups that build upon existing friendships, fictive kin networks, and the sense of community found among African Americans females. Sister circles appear to offer many of the components Black women desire in an anxiety intervention. In this article, we explore sister circles as an intervention for anxious African American women. Culturally-infused aspects from our sister circle work with middle-class African American women are presented. Further research is needed. PMID:22081747

  20. VizieR Online Data Catalog: W1J00 and W2J00 Transit Circle Catalogs (Rafferty+, 2016)

    NASA Astrophysics Data System (ADS)

    Rafferty, T. J.; Holdenried, E. R.; Urban, S. E.

    2016-06-01

    The W1J00, named because it was the first (of two) Washington transit circle catalog to be referred to the Equinox of J2000.0, is the result of observations made with the Six-inch Transit Circle in Washington, D.C., between September 1977 and July 1982. The observing program was structured to be absolute, in the sense that the positions were not explicitly relying on any previous observations. The absolute positions were defined with respect to an internally consistent frame that was unique to the particular instrument. Following the reductions, comparisons with stars from the Hipparcos Catalogue (European Space Agency 1997) revealed unaccounted for systematic differences on the level of 100-200mas. It was decided, therefore, to include data on both the absolute positions reduced in way common to many past Washington transit circle catalogs, as well as the positions differentially adjusted to the system of the Hipparcos Catalog. The W1J00 contains mean positions of 7267 stars and 4383 observations of solar system objects. The majority of the stars fall into two categories; those from the Fifth Fundamental Catalog (FK5; Fricke et al 1988), and those from the Catalog Of 3539 Zodiacal Stars For The Equinox 1950.0 (Robertson 1940). The solar system objects include the Sun, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, eight minor planets (Eunomia, Flora, Hebe, Iris, Juno, Metis, Pallas, and Vesta), and the dwarf planet Ceres. Characteristics of the W1J00 catalog: Category Range Average ------------------------------------------------------------- Magnitudes -1.6 to 10.4 7.18 RA standard errors of the mean 15 to 460 mas 98 mas Dec standard errors of the mean 10 to 400 mas 107 mas RA Number of observations / star 3 to 187 10 Dec Number of observations / star 2 to 179 10 Declination coverage -39 to +90 degrees ------------------------------------------------------------- Details of the W1J00 can be found in Rafferty, Holdenried, and Urban (2016, Publ. USNO, 2nd

  1. A Voyage around the Recumbent Stone Circles of North-East Scotland

    NASA Astrophysics Data System (ADS)

    Henty, Liz

    2015-05-01

    This paper details new archaeoastronomical research undertaken at the Recumbent Stone Circles (RSCs) of Scotland. Research to date has concentrated on the recumbent arrangement and the major theorists such as Thom, Ruggles and Burl, proposed that the recumbent and pillars are aligned to the lunar standstills or the passage of the moon over the recumbent. This research took a different voyage around the circles, which included checking all the stones of the circle for solar and stellar alignments as well as lunar alignments. It looks at nine RSCs, using both new plans drawn up by RCAHMS and plans published by Thom. The research was prompted by preliminary research, reported on at SEAC 2010, which detailed fieldwork completed at three sites. Because of the earlier focus on the recumbent, the RSCs have generally been interpreted in terms of a lunar narrative. By contrast, the aims of this research were to examine the circle in its entirety examining each circle stone for possible solar, lunar and stellar alignments using the dates of 2500 BC and 2000 BC. The results for all the circle stones showed that there were just as many solar as lunar alignments and that some stellar alignments may have been important symbolically.

  2. Black-hole black-string phase transitions in thermal (1 + 1)-dimensional supersymmetric Yang Mills theory on a circle

    NASA Astrophysics Data System (ADS)

    Aharony, Ofer; Marsano, Joseph; Minwalla, Shiraz; Wiseman, Toby

    2004-11-01

    We review and extend earlier work that uses the AdS/CFT correspondence to relate the black-hole black-string transition of gravitational theories on a circle to a phase transition in maximally supersymmetric (1 + 1)-dimensional SU(N) gauge theories at large N, again compactified on a circle. We perform gravity calculations to determine a likely phase diagram for the strongly coupled gauge theory. We then directly study the phase structure of the same gauge theory, now at weak 't Hooft coupling. In the interesting temperature regime for the phase transition, the (1 + 1)-dimensional theory reduces to a (0 + 1)-dimensional bosonic theory, which we solve using Monte Carlo methods. We find strong evidence that the weakly coupled gauge theory also exhibits a black hole black string-like phase transition in the large N limit. We demonstrate that a simple Landau Ginzburg-like model describes the behaviour near the phase transition remarkably well. The weak coupling transition appears to be close to the cusp between a first-order and a second-order transition.

  3. PID comes full circle: applications of V(D)J recombination excision circles in research, diagnostics and newborn screening of primary immunodeficiency disorders.

    PubMed

    van Zelm, Menno C; van der Burg, Mirjam; Langerak, Anton W; van Dongen, Jacques J M

    2011-01-01

    The vast majority of patients suffering from a primary immunodeficiency (PID) have defects in their T- and/or B-cell compartments. Despite advances in molecular diagnostics, in many patients no underlying genetic defect has been identified. B- and T-lymphocytes are unique in their ability to create a receptor by genomic rearrangement of their antigen receptor genes via V(D)J recombination. During this process, stable circular excision products are formed that do not replicate when the cell proliferates. Excision circles can be reliably quantified using real-time quantitative (RQ-)PCR techniques. Frequently occurring δREC-ψJα T-cell receptor excision circles (TRECs) have been used to assess thymic output and intronRSS-Kde recombination excision circles (KREC) to quantify B-cell replication history. In this perspective, we describe how TRECs and KRECs are formed during precursor - T- and B-cell differentiation, respectively. Furthermore, we discuss new insights obtained with TRECs and KRECs and specifically how these excision circles can be applied to support therapy monitoring, patient classification and newborn screening of PID.

  4. Students' Quality Control Circle: A Case Study on Students' Participation in the Quality Control Circle at the Faculty of Business and Management.

    ERIC Educational Resources Information Center

    Shariff, Siti Halijjah

    1999-01-01

    A pilot study evaluated participation of 18 undergraduate students for one year in two Students' Quality Control Circles (SQCC) at the Faculty of Business and Management, Institut Teknologi MARA (Malaysia). Feedback from the students indicated that the SQCC was a suitable learning process and that it could be adopted as a subject. (DB)

  5. On the organizing role of nonmuscular forces during performance of a giant circle in gymnastics.

    PubMed

    Sevrez, Violaine; Rao, Guillaume; Berton, Eric; Bootsma, Reinoud J

    2012-02-01

    Five elite gymnasts performed giant circles on the high bar under different conditions of loading (without and with 6-kg loads attached to the shoulders, waist or ankles). Comparing the gymnasts' kinematic pattern of movement with that of a triple-pendulum moving under the sole influence of nonmuscular forces revealed qualitative similarities, including the adoption of an arched position during the downswing and a piked position during the upswing. The structuring role of nonmuscular forces in the organization of movement was further reinforced by the results of an inverse dynamics analysis, assessing the contributions of gravitational, inertial and muscular components to the net joint torques. Adding loads at the level of the shoulders, waist or ankles systematically influenced movement kinematics and net joint torques. However, with the loads attached at the level of the shoulders or waist, the load-induced changes in gravitational and inertial torques provided the required increase in net joint torque, thereby allowing the muscular torques to remain unchanged. With the loads attached at the level of the ankles, this was no longer the case and the gymnasts increased the muscular torques at the shoulder and hip joints. Together, these results demonstrate that expert gymnasts skillfully exploit the operative nonmuscular forces, employing muscle force only in the capacity of complementary forces needed to perform the task.

  6. Experimental study of hemodynamics in the circle of willis

    PubMed Central

    2015-01-01

    Background The Circle of Willis (CoW) is an important collateral pathway of the cerebral blood flow. An experimental study of the cerebral blood flow (CBF) distribution in different anatomical variations may help to a better understanding of the collateral mechanism of the CoW. Methods An in-vitro test rig was developed to simulate the physiological cerebral blood flow in the CoW. Ten anatomical variations were considered in this study, include a set of different degrees of stenosis in L-ICA and L-ICA occlusion coexist with common anatomical variations. Volume flow rates of efferent arteries and pressure signals at the end of communicating arteries of each case were recorded. Physiological pressure waveforms were applied as inlet boundary condition. Results In the development of L-ICA stenosis, the total CBF decreases with the increase of stenosis degree. The blood supply of ipsilateral middle cerebral artery (MCA) was affected most by the stenosis of L-ICA. Anterior communicating artery (ACoA) and ipsilateral posterior communicating artery (PCoA) function as important collateral pathways of cerebral collateral circulation when unilateral stenosis occurred. The blood supply of anterior cerebral circulation was compensated by the posterior cerebral circulation through ipsilateral PCoA when L-ICA stenosis degree is greater than 40% and the affected side was compensated immediately by the unaffected side through ACoA. Blood flow of the anterior circulation and the total CBF reached the minimum among all cases studied when L-ICA occlusion coexist with the absence of PCoA. Conclusion The results demonstrated the flow distribution patterns of the CoW under anatomical variations and clarified the collateral mechanism of the CoW. The flow ACoA is the most sensitive indexes to the morphology change of ipsilateral ICA. The relative independence of the circulation in anterior and posterior sections of the CoW is not broken and the function of ipsilateral PCoA is not activated

  7. Introspection, empathy, and the semi-circle of mental health.

    PubMed

    Kohut, H

    1982-01-01

    Written shortly before his death, Heinz Kohut's last paper opens with a discussion of the paper 'Introspection, empathy, and psychoanalysis', written in 1959, which he presented at the Twenty-fifth Anniversary Meeting of the Chicago Institute for Psychoanalysis. In his first essay on the role of empathy in psychoanalysis, an essay that according to Kohut provided a foundation for many of his subsequent investigations in the field of depth psychology, he advanced the thesis that the introspective-empathic stance of the observer defines the science of psychoanalysis. The author explains that he was moved to propose this operational definition of psychoanalysis twenty-five years before because he felt that the introduction of the psychobiological concept of the drives (as well as various social psychological concepts) had not led to a true integration of psychoanalysis with biology or medicine but to a psychological and moral view of 'Guilty Man' that worked to distort the analyst's perception in the clinical and applied field. Kohut asserts that by defining itself operationally, psychoanalysis can accept itself as psychology, a psychology that studies man in terms of a self attempting to realize the programme laid down in his depth during the span of his life. The final section of the paper is devoted to a re-examination of man's intergenerational relationships in light of the shift Kohut advocates from psychobiology to psychology. The Oedipus complex is not to be understood as the end product of the uninfluentiable conflict of basic opposing instincts but as the result of interferences that impinge on man's development. Acknowledging the mythic power of Freud's formulation of the Oedipus complex, the author offers a dose of mythical counter-magic (to which the 'semi-circle of mental health' in the paper's title refers) and a re-interpretation of the story of King Oedipus. Kohut believes that the essence of human experience is not to be found in the biologically

  8. Off-great-circle paths in transequatorial propagation: 2. Nonmagnetic-field-aligned reflections

    NASA Astrophysics Data System (ADS)

    Tsunoda, Roland T.; Maruyama, Takashi; Tsugawa, Takuya; Yokoyama, Tatsuhiro; Ishii, Mamoru; Nguyen, Trang T.; Ogawa, Tadahiko; Nishioka, Michi

    2016-11-01

    There is considerable evidence that plasma structure in nighttime equatorial F layer develops from large-scale wave structure (LSWS) in bottomside F layer. However, crucial details of how this process proceeds, from LSWS to equatorial plasma bubbles (EPBs), remain to be sorted out. A major obstacle to success is the paucity of measurements that provide a space-time description of the bottomside F layer over a broad geographical region. The transequatorial propagation (TEP) experiment is one of few methods that can do so. New findings using a TEP experiment, between Shepparton (SHP), Australia, and Oarai (ORI), Japan, are presented in two companion papers. In Paper 1 (P1), (1) off-great-circle (OGC) paths are described in terms of discrete and diffuse types, (2) descriptions of OGC paths are generalized from a single-reflection to a multiple-reflection process, and (3) discrete type is shown to be associated with an unstructured but distorted upwelling, whereas the diffuse type is shown to be associated with EPBs. In Paper 2 (P2), attention is placed on differences in east-west (EW) asymmetry, found between OGC paths from the SHP-ORI experiment and those from another near-identical TEP experiment. Differences are reconciled by allowing three distinct sources for the EW asymmetries: (1) reflection properties within an upwelling (see P1), (2) OGC paths that depend on magnetic declination of geomagnetic field (B), and (3) OGC paths supported by non-B-aligned reflectors at latitudes where inclination of B is finite.

  9. Morphological variations of the peripapillary circle of Zinn-Haller by flat section

    PubMed Central

    Ko, M.; Kim, D.; Ahn, Y.

    1999-01-01

    AIMS—To evaluate the morphometric and morphological variations of the circle of Zinn-Haller (CZH) in the human eye.
METHODS—42 human enucleated eyes were used in this study. After transverse flat thick sections were cut through the optic nerve and adjacent sclera, tissue sections were stained with haematoxylin and eosin or examined immediately by wet preparation under a light microscope. The average vessel diameter of the arterial circle and the average distance between the optic nerve head (ONH) and the arterial circle were determined. Various branching patterns of the CZH were also evaluated.
RESULTS—The vessel diameter of the arterial circle was 123 (SD 75) µm (range 20-230 µm). The distance of the CZH from the ONH margin was 403 (352) µm (0-1050 µm). The CZH gave off branches to the optic nerve and to the peripapillary choroid (PPC) with various branching patterns especially at the entry point of paraoptic short posterior ciliary artery.
CONCLUSIONS—The CZH exists within a variable distance from the ONH and its average diameter is similar to that of the central retinal vessels though it shows marked variation even in the same circle. The CZH also shows variable configurations in branching patterns. These variations may act as contributing factors that are responsible for the individual susceptibility of the anterior optic nerve and the PPC to circulatory disturbances.

 PMID:10381675

  10. Infraorbital Dark Circles: A Review of the Pathogenesis, Evaluation and Treatment.

    PubMed

    Vrcek, Ivan; Ozgur, Omar; Nakra, Tanuj

    2016-01-01

    Infraorbital dark circles represent a common and multifactorial challenge in the world of aesthetic medicine and are the result of a variety of factors including deep facial anatomy, soft tissue changes, as well as contributions from the skin. A variety of treatment options exist, and a customised management strategy can be developed for the particular anatomic changes present. A literature search using MEDLINE and non-MEDLINE sources was performed utilising keywords including: 'Dark circles' 'infraorbital dark circles', 'infraorbital pigment', 'under-eye circles' and 'lower eyelid bags'. A comprehensive review of the literature was performed and the data were assimilated with evidence from our practice. This review provides a detailed discussion of the aetiology, pathogenesis, evaluation and management of infraorbital dark circles. An understanding of the deep and superficial anatomy is crucial to the management of this complex entity. The armamentarium for treatment includes minimally invasive interventions such as makeup and cosmeceuticals, a variety of laser and chemical treatments, fillers and fat transfer, as well as more invasive surgical manoeuvres.

  11. [Inspiratory and expiratory resistance of 8 semi-closed circle systems].

    PubMed

    Feigenwinter, P; Zbinden, A M

    1991-08-01

    The resistance of a circle system is an important factor that determines the respiratory effort of the patient. The inspiratory and expiratory resistances were measured in eight semi-closed circle systems used in Europe: Dräger Cicero, Dräger 8 ISO, Dräger AV1, Ohmeda Modulus II Plus, Gambro Engström Elsa, Siemens Servo Ventilator 900 D with circle system 985, Siemens Ventilator 710, and Megamed 700A with circle system 219. The measurements were all performed in the position "spontaneous breathing" according to a new proposal of the CEN (Comité Européen de Normalisation). The following circle systems exceeded the proposed limit of 0.6 kPa at a gas flow of 60 l/min (with CO2-Absorber): Dräger AV1 in expiration and Siemens Servo Ventilator in both expiration and inspiration. The expiratory resistance was also determined by using intermittent flows. The results differed, as the expiratory gas flow can be influenced by the falling or rising ventilator bellows. The authors conclude that considerable differences exist between various breathing systems and that not all systems can be recommended for use in patients with limited breathing force, such as small children.

  12. Specific RNA self-cleavage in coconut cadang cadang viroid: potential for a role in rolling circle replication.

    PubMed Central

    Liu, Y H; Symons, R H

    1998-01-01

    The rolling circle replication of the small, single-stranded viroid RNAs requires a specific processing reaction to produce monomeric RNAs that are ligated into the final circular form. For avocado sunblotch viroid, peach latent mosaic viroid, and chrysanthemum chlorotic mottle viroid, the hammerhead self-cleavage reaction is considered to provide this processing reaction. We have searched for a similar type of reaction in the 246-nt coconut cadang cadang viroid, the smallest viroid of the 24-member potato spindle tuber viroid (PSTV) group. RNA transcripts prepared from the cloned central or C domain of this viroid self-cleaved specifically after denaturation with methylmercuric hydroxide followed by incubation in the presence of spermidine but in the absence of added magnesium ions. The unique cleavage site was located in the bottom strand of the C domain within a potential hairpin structure that is conserved within members of all three subgroups of the PSTV group of viroids. PMID:9630248

  13. Women and Chemistry in Regency England: New Light on the Marcet Circle.

    PubMed

    Leigh, G Jeffery; Rocke, Alan J

    2016-02-01

    Jane Marcet's Conversations on Chemistry (first edition, 1806) was possibly the best-selling English-language chemistry book of the first half of the nineteenth century. Recent scholarship has explored the degree to which her husband assisted in the writing of the book, without diminishing the high merits of the author. Previously unpublished correspondence, some of which appears here for the first time, casts new light on the social and professional circle of Jane and Alexander Marcet, including its influence on Jane's book. One of the members of that circle was a hitherto unrecognised but highly capable young female chemist, Frederica Sebright. The story told here underlines the tensions in elite circles in early nineteenth-century England between broad-minded acceptance and patronising limitations for women in science.

  14. Modeling Particle Rolling Behavior by the Modified Eccentric Circle Model of DEM

    NASA Astrophysics Data System (ADS)

    Chang, Yi-Long; Chen, Tsung-Hsien; Weng, Meng-Chia

    2012-09-01

    This study proposes a modified eccentric circle model to simulate the rolling resistance of circle particles through the distinct element method (DEM) simulation. The proposed model contains two major concepts: eccentric circle and local rotational damping. The mass center of a circular particle is first adjusted slightly for eccentricity to provide rotational stiffness. Local rotational damping is adopted to dissipate energy in the rotational direction. These associated material parameters can be obtained easily from the rolling behavior of one rod. This study verifies the proposed model with the repose angle tests of chalk rod assemblies, and the simulated results were satisfactory. Simulations using other existing models were also conducted for comparison, showing that the proposed model achieved better results. A landslide model test was further simulated, and this simulation agreed with both the failure pattern and the sliding process. In conclusion, particle rolling simulation using the proposed model appears to approach the actual particle trajectory, making it useful for various applications.

  15. Traffic flow behavior at a single lane roundabout as compared to traffic circle

    NASA Astrophysics Data System (ADS)

    Lakouari, N.; Ez-Zahraouy, H.; Benyoussef, A.

    2014-09-01

    In this paper, we propose a stochastic Cellular Automata (CA) model to study traffic flow at a single-lane urban roundabout (resp. traffic circle) of N entry points (resp. exit points), the entry points are controlled by rates α1 and α2 while the removal rates from the exit points are denoted by β. The traffic is controlled by a self-organized scheme. Based on computer simulation, density profiles, global density and current are calculated in terms of rates. Furthermore, the phase diagrams for roundabout as well as traffic circle are constructed. It has turned out that the phase diagrams consist essentially of two phases namely free flow and jamming. It is noted that the typology of the phase diagrams of the roundabout is not similar to it in the traffic circle. Furthermore, we have compared the performance of the two systems in terms of the geometrical properties and the number of entry points.

  16. An analysis of two classes of grazing incidence mirrors for use with Rowland circle spectrometers

    NASA Technical Reports Server (NTRS)

    Green, James; Bowyer, Stuart

    1986-01-01

    Results are presented of a comparative analysis of Hettrick Bowyer Type II (HBII) and Wolter-Schwarzschild Type II (WSII) optics for use with Rowland circle spectrometers. The HBII can substitute, with few exceptions, for a WSII in any Rowland circle with little change in spectrometer performance or design. However, the HBII telescope offers several clear advantages over the WSII in these configurations. Because the HBII employs a virtual focus, it requires a much shorter instrument length than a WSII. For example, a 3-m Rowland circle spectrometer, fed by an optimized, f/10, 1-m diameter WSII, has a total instrument length of 6 m. If a HBII is used to feed the identical spectrometer, the entire instrument length can be as little as 3 m. In addition, the improved imaging gained with the larger graze angles of the HBII design results in better resolution in slitless operation modes.

  17. Mosh pits and Circle pits: Collective motion at heavy metal concerts

    NASA Astrophysics Data System (ADS)

    Bierbaum, Matthew; Silverberg, Jesse L.; Sethna, James P.; Cohen, Itai

    2013-03-01

    Heavy metal concerts present an extreme environment in which large crowds (~102 -105) of humans experience very loud music (~ 130 dB) in sync with bright, flashing lights, often while intoxicated. In this setting, we find two types of collective motion: mosh pits, in which participants collide with each other randomly in a manner resembling an ideal gas, and circle pits, in which participants run collectively in a circle forming a vortex of people. We model these two collective behaviors using a flocking model and find qualitative and quantitative agreement with the behaviors found in videos of metal concerts. Futhermore, we find a phase diagram showing the transition from a mosh pit to a circle pit as well as a predicted third phase, lane formation.

  18. Great circle solution to polarization-based quantum communication (QC) in optical fiber

    DOEpatents

    Nordholt, Jane Elizabeth; Peterson, Charles Glen; Newell, Raymond Thorson; Hughes, Richard John

    2016-03-15

    Birefringence in optical fibers is compensated by applying polarization modulation at a receiver. Polarization modulation is applied so that a transmitted optical signal has states of polarization (SOPs) that are equally spaced on the Poincare sphere. Fiber birefringence encountered in propagation between a transmitter and a receiver rotates the great circle on the Poincare sphere that represents the polarization bases used for modulation. By adjusting received polarizations, polarization components of the received optical signal can be directed to corresponding detectors for decoding, regardless of the magnitude and orientation of the fiber birefringence. A transmitter can be configured to transmit in conjugate polarization bases whose SOPs can be represented as equidistant points on a great circle so that the received SOPs are mapped to equidistant points on a great circle and routed to corresponding detectors.

  19. Hydraulic characteristics of an underdrained irrigation circle, Muskegon County wastewater disposal system, Michigan

    USGS Publications Warehouse

    McDonald, M.G.

    1980-01-01

    Muskegon County, Mich., disposes of wastewater by spray irrigating farmland on its waste-disposal site. Buried drains in the highly permeable unconfined aquifer at the site control the level of the water table. Hydraulic conductivity of the aquifer and drain leakance, the reciprocal of resistance to flow into the drains, was determined at a representative irrigation circle while calibrating a model of the ground-water flow system. Hydraulic conductivity is .00055 meter per second, in the north zone of the circle, and .00039 meter per second in the south zone. Drain leakance is low in both zones: 0.0000029 meter per second in the north and 0.0000095 meter per second in the south. Low drain leakance is responsible for waterlogging when irrigation rates are maintained at design levels. The capacity of the study circle to accept wastewater has been reduced by more than 35%.

  20. Circles-in-the-sky searches and observable cosmic topology in a flat universe

    NASA Astrophysics Data System (ADS)

    Mota, B.; Rebouças, M. J.; Tavakol, R.

    2010-05-01

    In a universe with a detectable nontrivial spatial topology, the last scattering surface contains pairs of matching circles with the same distribution of temperature fluctuations—the so-called circles-in-the-sky. Searches for nearly antipodal circles-in-the-sky in maps of cosmic microwave background radiation have so far been unsuccessful. This negative outcome, along with recent theoretical results concerning the detectability of nearly flat compact topologies, is sufficient to exclude a detectable nontrivial topology for most observers in very nearly flat positively and negatively curved universes, whose total matter-energy density satisfies 0<|Ωtot-1|≲10-5. Here, we investigate the consequences of these searches for observable nontrivial topologies if the Universe turns out to be exactly flat (Ωtot=1). We demonstrate that in this case, the conclusions deduced from such searches can be radically different. We show that, although there is no characteristic topological scale in the flat manifolds, for all multiply-connected orientable flat manifolds, it is possible to directly study the action of the holonomies in order to obtain a general upper bound on the angle that characterizes the deviation from antipodicity of pairs of matching circles associated with the shortest closed geodesic. This bound is valid for all observers and all possible values of the compactification length parameters. We also show that in a flat universe, there are observers for whom the circles-in-the-sky searches already undertaken are insufficient to exclude the possibility of a detectable nontrivial spatial topology. It is remarkable how such small variations in the spatial curvature of the Universe, which are effectively indistinguishable geometrically, can have such a drastic effect on the detectability of cosmic topology. Another important outcome of our results is that they offer a framework with which to make statistical inferences from future circles-in-the-sky searches on

  1. "Socratic Circles are a Luxury": Exploring the Conceptualization of a Dialogic Tool in Three Science Classrooms

    NASA Astrophysics Data System (ADS)

    Copelin, Michelle Renee

    Research has shown that dialogic instruction promotes learning in students. Secondary science has traditionally been taught from an authoritative stance, reinforced in recent years by testing policies requiring coverage. Socratic Circles are a framework for student-led dialogic discourse, which have been successfully used in English language arts and social studies classrooms. The purpose of this research was to explore the implementation process of Socratic Circles in secondary science classes where they have been perceived to be more difficult. Focusing on two physical science classes and one chemistry class, this study described the nature and characteristics of Socratic Circles, teachers' dispositions toward dialogic instruction, the nature and characteristics of student discussion, and student motivation. Socratic Circles were found to be a dialogic support that influenced classroom climate, social skills, content connections, and student participation. Teachers experienced conflict between using traditional test driven scripted teaching, and exploring innovation through dialogic instruction. Students experienced opportunities for peer interaction, participation, and deeper discussions in a framework designed to improve dialogic skills. Students in two of the classrooms showed evidence of motivation for engaging in peer-led discussion, and students in one class did not. The class that did not show evidence of motivation had not been given the same scaffolding as the other two classes. Two physical science teachers and one chemistry teacher found that Socratic Circles required more scaffolding than was indicated by their peers in other disciplines such as English and social studies. The teachers felt that student's general lack of background knowledge for any given topic in physical science or chemistry necessitated the building of a knowledge platform before work on a discussion could begin. All three of the teachers indicated that Socratic Circles were a

  2. From the Weyl quantization of a particle on the circle to number–phase Wigner functions

    SciTech Connect

    Przanowski, Maciej Brzykcy, Przemysław Tosiek, Jaromir

    2014-12-15

    A generalized Weyl quantization formalism for a particle on the circle is shown to supply an effective method for defining the number–phase Wigner function in quantum optics. A Wigner function for the state ϱ{sup ^} and the kernel K for a particle on the circle is defined and its properties are analysed. Then it is shown how this Wigner function can be easily modified to give the number–phase Wigner function in quantum optics. Some examples of such number–phase Wigner functions are considered.

  3. [[Role of dyslipidemia in pathogenesis of vascular events among Arctic Circle population].

    PubMed

    Maslov, L N; Vychuzhanova, E A; Gorbunov, A S; Tsibul'nikov, S Iu

    2014-01-01

    Habitation within the polar circle increases cardiovascular mortality rate and particularly increases mortality as a result of coronary events. The main reason of elevation of mortality from these diseases is a dyslipidemia which developed more among alien population residing long time in Far North. Dyslipidemia is less found among aboriginal population of Arctic Circle keeping traditional way of life and respectively it is low rate of mortality from coronary heart disease. The data showed that low rate of dyslipidemia among aboriginal population of North regions depends on fish consumption which is high content of Ω3-polyunsaturated fatty acids.

  4. Vicious circles of punishment: a reading of Melanie Klein's Envy and gratitude.

    PubMed

    Smith, Henry F

    2008-01-01

    Staged as a moral drama, Melanie Klein's Envy and Gratitude (1957) straddles two eras: one reflecting a simpler more concrete, historical method, and the other an approach of greater complexity, focused on the transferential moment. Embedded within the transference are the vicious circles of envy and punishment that are the hallmark of Klein's text. Punishment itself which is always punishment of both self and other, creates its own vicious circle, set in motion by a single act. In the sadomasochistic enactments that result, the moral force of Klein's categories fuels the countertransference. A detailed clinical hour is presented.

  5. Expanding the Circle: Respecting the Past Preparing for the Future.

    ERIC Educational Resources Information Center

    Ness, Jean E.; Huisken, Jennifer S.

    This curriculum was developed to support American Indian high school students in their transition from high school to postsecondary life. It provides a structured process and culturally relevant activities that can be led by either teachers, tribal elders, community members, or paraprofessionals. The curriculum is based on principles such as a…

  6. The Box and the Circle--Two Systems of Life: A Model for Understanding Native-Non-Native Issues.

    ERIC Educational Resources Information Center

    Derrick, Jann

    Working as a family systems therapist with Native and non-Native families, the author observed two opposing social systems. Non-native families systems typify "The Box System," whereas native family systems portray "The Circle System." A few characteristics of the Circle System are: (1) a focus on life and peacefulness; (2) females and children…

  7. A Study of Traditional Circle Games of Five-Year-Old United States Public School Kindergarten Children.

    ERIC Educational Resources Information Center

    Rothlein, Liz; Einspruch, Eric

    A total of 203 teachers of 5-year-olds in public school kindergartens representing 35 states responded to a questionnaire about traditional circle games. The teachers were asked to identify three of the favorite traditional circle games used in their classrooms and to indicate how often and how long the games were played. In addition, teachers…

  8. Talking Books: Gender and the Responses of Adolescents in Literature Circles

    ERIC Educational Resources Information Center

    Lloyd, Rachel Malchow

    2006-01-01

    The use of student-led discussions, or literature circles, offers the potential to engage all students through a more democratic, dialogic approach. The central goal of this research was to understand how adolescents practise literacy within the context of a peer reading group, and how gender impacts these practices. Transcripts of student-led…

  9. Cultural Safety Circles and Indigenous Peoples' Perspectives: Inclusive Practices for Participation in Higher Education

    ERIC Educational Resources Information Center

    Aseron, Johnnie; Greymorning, S. Neyooxet; Miller, Adrian; Wilde, Simon

    2013-01-01

    Indigenous experiences, as found within traditional ways and cultural practices, are an acknowledgement of traditional methods for sharing, learning, and collective knowledge development and maintenance. The application of Cultural Safety Circles can help provide a collective space where definitions for cultural and educational exchange can take…

  10. Encounters with Wisdom: A Case Study of Community Worker Reflection Circles in San Antonio, TX

    ERIC Educational Resources Information Center

    Arispe, Don D.

    2013-01-01

    This case study focuses upon the transformational experiences of 28 social service and pastoral workers engaged in a Reflection Circle Process (RCP) in San Antonio, TX. The RCP involves the writing of a holistic journal entry, known as a process note, coupled with an in-depth exploration of the note with the help of a group of trusted peers, known…

  11. A Queer Circle of Friends, Indeed! The School Social as Intervention or as Movement

    ERIC Educational Resources Information Center

    Thompson, S. Anthony

    2012-01-01

    The purpose of this paper to present two approaches intended to support the social lives of those typically on the borders of school life. Circles of friends (CoFs) was designed to assist students labelled with disabilities, while Gay-straight alliances (GSAs) addresses needs of supporting students who identify as lesbian, gay, bisexual,…

  12. STEM High School Teachers' Views of Implementing PBL: An Investigation Using Anecdote Circles

    ERIC Educational Resources Information Center

    deChambeau, Aimée L.; Ramlo, Susan E.

    2016-01-01

    Problem-based learning (PBL) has been gaining in popularity, especially within the context of STEM-based (science, technology, engineering, and mathematics) schools. Program assessments for these schools typically focus on student standardized test scores rather than the needs of the teachers. This study utilized anecdote circles, storytelling via…

  13. Dinner Tables and Concentric Circles: A Harmony of Mathematics, Music, and Physics

    ERIC Educational Resources Information Center

    Douthett, Jack; Krantz, Richard J.

    2008-01-01

    How should men and women be seated around a dinner table to maximize conversation between members of the opposite sex? What can be said about the distribution of points around two concentric circles? How are the white and black keys on the piano keyboard organized? What spin configuration in the Ising model minimizes energy? These four problems…

  14. Early-Years Teachers' Concept Images and Concept Definitions: Triangles, Circles, and Cylinders

    ERIC Educational Resources Information Center

    Tsamir, Pessia; Tirosh, Dina; Levenson, Esther; Barkai, Ruthi; Tabach, Michal

    2015-01-01

    This study investigates practicing early-years teachers' concept images and concept definitions for triangles, circles, and cylinders. Teachers were requested to define each figure and then to identify various examples and non-examples of the figure. Teachers' use of correct and precise mathematical language and reference to critical and…

  15. Using Reading Circles Strategy for Developing Preparatory Students' Critical Reading Skills and Social Skills

    ERIC Educational Resources Information Center

    Abdelrasoul, Mohamed Mahmoud Ibrahim

    2014-01-01

    The present study aimed at developing the necessary critical reading skills and social skills of the Egyptian EFL second year preparatory school students, through a proposed program based on using reading circles strategy. The study participants were 44 students from Sohag Experimental Preparatory School in Sohag Governorate. Instruments of the…

  16. Mathematical Practices in a Technological Setting: A Design Research Experiment for Teaching Circle Properties

    ERIC Educational Resources Information Center

    Akyuz, Didem

    2016-01-01

    This article documents the classroom mathematical practices observed in a collegiate level teacher education course related to the circle topic. The course, which was prepared as design research, utilized a dynamic geometry environment which influenced the type and nature of the evolved mathematical practices. The study uses emergent perspective…

  17. Treatment of infraorbital dark circles using 694-nm fractional Q-switched ruby laser.

    PubMed

    Xu, Tian-Hua; Li, Yuan-Hong; Chen, John Z S; Gao, Xing-Hua; Chen, Hong-Duo

    2016-12-01

    The objective of this study was to evaluate the efficacy and safety of using a 694-nm fractional Q-switched ruby laser to treat infraorbital dark circles. Thirty women with infraorbital dark circles (predominant color: dark/brown) participated in this open-labeled study. The participants received eight sessions of 694-nm fractional Q-switched ruby laser treatment using a fluence of 3.0-3.5 J/cm(2), at an interval of 7 days. The melanin deposition in the lesional skin was observed in vivo using reflectance confocal microscopy (RCM). The morphological changes were evaluated using a global evaluation, an overall self-assessment, and a Mexameter. Twenty-eight of the 30 patients showed global improvements that they rated as excellent or good. Twenty-six patients rated their overall satisfaction as excellent or good. The melanin index indicated a substantial decrease from 240.44 (baseline) to 194.56 (P < 0.05). The RCM results showed a dramatic decrease in melanin deposition in the upper dermis. The adverse effects were minimal. The characteristic finding of dark/brown infraorbital dark circles is caused by increased melanin deposition in the upper dermis. The treatment of these infraorbital dark circles using a 694-nm fractional QSR laser is safe and effective.

  18. Strategic Framing Study Circles: Toward a Gold Standard of Framing Pedagogy

    ERIC Educational Resources Information Center

    Feinberg, Jane

    2009-01-01

    This article explains how communities of practice have been developed as part of FrameWorks' field-building efforts. Strategic Framing Study Circles, as they are known, have been conducted with four statewide coalitions, one group of national organizations, and an emerging regional coalition. The goal of each community of practice is to build…

  19. Constructing Knowledge about the Trigonometric Functions and Their Geometric Meaning on the Unit Circle

    ERIC Educational Resources Information Center

    Altman, Renana; Kidron, Ivy

    2016-01-01

    Processes of knowledge construction are investigated. A learner is constructing knowledge about the trigonometric functions and their geometric meaning on the unit circle. The analysis is based on the dynamically nested epistemic action model for abstraction in context. Different tasks are offered to the learner. In his effort to perform the…

  20. Transforming Lives: Women's Study Circles in Historical and Cross-Cultural Perspective.

    ERIC Educational Resources Information Center

    Johnson, Linda L.

    1989-01-01

    Examines the role which women's study groups and writing circles have played in the education of women in Japan, China, and the United States. Serves as an introduction to a cross-cultural study of women's history in the three cultures. Points out that the course raises questions about the politics of women's education. (LS)

  1. Using Social Networks and ICTs to Enhance Literature Circles: A Practical Approach

    ERIC Educational Resources Information Center

    Walker, Andrea

    2010-01-01

    The purpose of this paper is to describe and demonstrate how social networks such as "Facebook" and "Goodreads", and information and communication technologies (ICTs) tools like laptops and iPods can support and enhance literature circles. The innovation described is implemented by the library and aims to promote reading for…

  2. Dirac Circles and Quantum Hall Effect in 3D Inversion-Symmetric Crystals

    NASA Astrophysics Data System (ADS)

    Wieder, Benjamin J.; Kim, Youngkuk; Kane, C. L.

    2015-03-01

    In the presence of inversion and time-reversal symmetries, materials with weak spin-orbit coupling may host topologically protected Dirac line nodes. A band inversion transition in these systems can produce a line node which closes on itself and forms a protected Dirac circle. The surfaces parallel to this circle host zero-energy puddles in momentum space which are flat if the inverting bands have the same effective mass. In cases with differing effective masses, the surface modes disperse, but the bulk Dirac circle remains gapless. Adding an external magnetic field perpendicular to this circle creates surface Landau levels, whose number can be controlled by tuning the field strength. When a new level is created or destroyed, the bulk becomes gapless and the zero-temperature bulk conductivity displays a sharp peak. The sequence of conductivity peaks describes an unusual manifestation of the integer quantum hall effect. We characterize surface and bulk transport as a function of magnetic field strength and in the presence of disorder.

  3. The Inner Circle: Staff Development and Community Education, Bill C-61. Summary Description.

    ERIC Educational Resources Information Center

    Loucks, Bryan

    The Inner Circle project addresses the leadership staff and community education needs of Ontario's Native peoples as they relate to the introduction and implementation of the Young Offenders Act of 1984. The project is the first phase of a unique education process supporting self-determination, local control, and institution-building among…

  4. Using Literature Circles to Increase Reading Comprehension in Third Grade Elementary Students

    ERIC Educational Resources Information Center

    Briggs, Shawna R.

    2010-01-01

    Reading comprehension strategies are important skills for a child to learn. Good strategies support struggling students to be more successful in all subjects at school as reading is the basis for subsequent mastery of most subjects (Bender & Larkin, 2003). This action research project examined the use of literature circles in a third grade class.…

  5. Engagement Angle Modeling for Multiple-circle Continuous Machining and Its Application in the Pocket Machining

    NASA Astrophysics Data System (ADS)

    WU, Shixiong; MA, Wei; BAI, Haiping; WANG, Chengyong; SONG, Yuexian

    2017-03-01

    The progressive cutting based on auxiliary paths is an effective machining method for the material accumulating region inside the mould pocket. But the method is commonly based on the radial depth of cut as the control parameter, further more there is no more appropriate adjustment and control approach. The end-users often fail to set the parameter correctly, which leads to excessive tool load in the process of actual machining. In order to make more reasonable control of the machining load and tool-path, an engagement angle modeling method for multiple-circle continuous machining is presented. The distribution mode of multiple circles, dynamic changing process of engagement angle, extreme and average value of engagement angle are carefully considered. Based on the engagement angle model, numerous application techniques for mould pocket machining are presented, involving the calculation of the milling force in multiple-circle continuous machining, and rough and finish machining path planning and load control for the material accumulating region inside the pocket, and other aspects. Simulation and actual machining experiments show that the engagement angle modeling method for multiple-circle continuous machining is correct and reliable, and the related numerous application techniques for pocket machining are feasible and effective. The proposed research contributes to the analysis and control tool load effectively and tool-path planning reasonably for the material accumulating region inside the mould pocket.

  6. Circle of Security in Child Care: Putting Attachment Theory into Practice in Preschool Classrooms

    ERIC Educational Resources Information Center

    Cooper, Glen; Hoffman, Kent; Powell, Bert

    2017-01-01

    This article describes the Circle of Security-Classroom (COS-C) approach to applying attachment theory in preschool settings. Early childhood is an incubator for a wide range of development including the underpinnings of school readiness. Secure teacher-child relationships support this process. However, most preschool staff members lack guidance…

  7. The Listening Circle: Using the SBI Model to Enhance Peer Feedback

    ERIC Educational Resources Information Center

    Bommelje, Rick

    2012-01-01

    The Listening Circle is a learning activity that is designed to provide students with the opportunity to connect listening knowledge with observed behaviors and to strengthen student peer feedback. Not knowing how to give feedback can result in messages that are confusing, tactless, and counter-productive. Many feedback messages leave the receiver…

  8. An Examination of Children's Oral Storytelling in a First Grade Storytelling Circle

    ERIC Educational Resources Information Center

    West, Jean Ann

    2012-01-01

    The purposes of this naturalistic, descriptive study were to examine the stories that children in one first grade classroom told in a storytelling circle, how the children's knowledge, in-school experiences, and out-of-school experiences were reflected in their stories, and how the children used their knowledge and experiences as tools to…

  9. Making a Circle: Tool Use and the Spaces where We Live

    ERIC Educational Resources Information Center

    Noble, Tracy; DiMattia, Cara; Nemirovsky, Ricardo; Barros, Apolinario

    2006-01-01

    A group of high school students created a drawing of a circle using a device called the Drawing Machine. To describe their experiences, we propose an alternative to the idea that to master a tool one must create a mental version of the tool. We suggest, instead, that as students change their relationships to a tool over time, their lived-in spaces…

  10. The Pervasiveness and Impact of Corporate Quality Circles: A Survey of Major American Corporations.

    ERIC Educational Resources Information Center

    Hellweg, Susan A.; And Others

    To assess the pervasiveness of quality circles in American corporations, as well as to ascertain perceptions of their impact in terms of various organizational outcomes, a 45-item questionnaire was mailed to personnel directors of the Fortune 500 corporations. Some time after the initial mailing, a follow-up mailing was executed to maximize the…

  11. A Refinement of Collaborative Circles Theory: Resource Mobilization and Innovation in an Emerging Sport

    ERIC Educational Resources Information Center

    Corte, Ugo

    2013-01-01

    Farrell's (2001) theory of collaborative circles provides a useful frame for analyzing the interpersonal dynamics that enable creative collaboration in small groups, but it leaves contextual factors of collaboration undertheorized. Using ethnographic data on freestyle BMXers in Greenville, North Carolina, this article demonstrates how resource…

  12. Dear Nel: Opening the Circles of Care (Letters to Nel Noddings)

    ERIC Educational Resources Information Center

    Lake, Robert

    2012-01-01

    This collection is a moving tribute to Nel Noddings, a fascinating and influential scholar who has contributed greatly to numerous fields, including education, feminism, ethics, and the study of social justice and equity. "Dear Nel: Opening the Circles of Care" presents contributions from renowned teachers, educators, and activists, such as David…

  13. 1. View to west along Green Street/The Circle showing partial ...

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

    1. View to west along Green Street/The Circle showing partial southeast elevation and facade (northeast elevation) of Carpenter & Paint Shop, with Medical Storage Building (HABS No. VA-1287-K) and Central Power House (HABS No. VA-1287-J) beyond - Portsmouth Naval Hospital, Carpenter & Paint Shop, Green Street, Portsmouth, Portsmouth, VA

  14. Circle Justice: A Creative Arts Approach to Conflict Resolution in the Classroom

    ERIC Educational Resources Information Center

    Gibbons, Karen

    2010-01-01

    This brief report describes a cooperative classroom art therapy intervention in a public elementary school that provided conflict resolution education, social learning, and group cohesion among sixth-grade students. The organizing framework of a "circle justice" group explored the roles of fictional characters in conflict, including…

  15. Literature Circles: Meeting Reading Standards, Making Personal Connections, and Appreciating Other Interpretations

    ERIC Educational Resources Information Center

    Latendresse, Carter

    2004-01-01

    This article discusses a reading instruction applicable to widely diverse classrooms, because it weaves together dynamic strands from three approaches to teaching reading: literature circle method, reciprocal teaching, and modern literary theories. The author presents three stages to achieve reading success: (1) applying the key features of…

  16. "Telling Stories Long into the Night": Romantic Circles High School Project.

    ERIC Educational Resources Information Center

    Walton, Brenda H.; Bork, Tara

    2001-01-01

    Reports on the authors' experiences in the Romantic Circles (RC) High School Project. Considers how RC High enables technology to be used as a tool in the study of literature and culture of the past, subjects that often seem dead and remote from a student's concern. (SG)

  17. Always Searching for Strengths: Interviewing and Counseling with the Circle of Courage

    ERIC Educational Resources Information Center

    Frankowski, Barbara; Duncan, Paula

    2013-01-01

    Several excellent frameworks exist that define components of positive youth development and demonstrate an inverse relationship with adolescent risks (Ginsburg, 2007). The authors have found that many of their colleagues have been drawn to the Circle of Courage for its clarity and spirit (Brendtro, Brokenleg, & Van Bockern, 2002). This model is…

  18. Runaway Climate Change as Challenge to the "Closing Circle" of Education for Sustainable Development

    ERIC Educational Resources Information Center

    Selby, David; Kagawa, Fumiyo

    2010-01-01

    Education for sustainable development (ESD) is the latest and thickest manifestation of the "closing circle" of policy-driven environmental education. Characterised by definitional haziness, a tendency to blur rather than lay bare inconsistencies and incompatibilities, and a cozy but ill-considered association with the globalisation agenda, the…

  19. Training the Scientific Thinking Circle in Pre- and Primary School Children

    ERIC Educational Resources Information Center

    Dejonckheere, Peter J. N.; Van De Keere, Kristof; Mestdagh, Nele

    2009-01-01

    Using two experiments, the authors examined the extent to which the scientific thinking circle can be used as heuristics to support scientific thinking in a classroom of children between the ages of 3 and 9 years old. To do this, the authors asked the children to build a bridge, raft, or electrical circuit using the material available to them.…

  20. Learners' Perceptions toward Pronunciation Instruction in Three Circles of World Englishes

    ERIC Educational Resources Information Center

    Kang, Okim

    2015-01-01

    From the perspective of World Englishes (i.e., varieties of English in different regions of the world), mutual intelligibility is a key issue for both listeners and speakers. Nevertheless, learners often have an idealized notion of native-speaker spoken norms and may be in favor of more prestigious inner circle models than others. This study…

  1. "Helping Circles" Giving High School Students a Helping Hand with Writing.

    ERIC Educational Resources Information Center

    Johnson, Mary Jo

    1988-01-01

    A teaching strategy is described that provides controlled support to hearing-impaired high school students through teacher-led "helping circles" to encourage elaboration and exploration in their writing. It enables students to share their written work in class, have an audience for their work, and provide and receive helpful criticism. (VW)

  2. Determination of positions of solar system bodies at Repsold meridian circle from 1992 till 1999

    NASA Astrophysics Data System (ADS)

    Maigurova, N. V.; Pogoniy, A. D.; Pyshnenko, V. N.; Sibilev, V. P.

    2002-04-01

    Position of the Solar system bodies: Uran, Neptune, Galilean satellites of Jupiter, satellite of Saturn Titan, Ceres, Pallas, Juno, Vesta, Hebe, Iris, and Melpomene were obtained from observations at Repsold Meridian Circle of Nikolaev Astronomical Observatory made in 1992-1999.

  3. Circle Talks as Situated Experiential Learning: Context, Identity, and Knowledgeability in "Learning from Reflection"

    ERIC Educational Resources Information Center

    Seaman, Jayson; Rheingold, Alison

    2013-01-01

    This article presents research that used ethnographic and sociolinguistic methods to study ways participants learn through reflection when carried out as a "circle talk." The data indicate that participants in the event (a) invoked different contextual frames that (b) implicated them in various identity positions, which (c) affected how…

  4. Functions of Rep and Rep' during porcine circovirus rolling-circle replication

    Technology Transfer Automated Retrieval System (TEKTRAN)

    PCV replicates its single-stranded (ss) DNA genome via the rolling-circle replication (RCR) mechanism. In contrast to other RCR biological systems which utilize only one multi-functional protein (Rep) to replicate their respective genomes, PCV requires two proteins (Rep and Rep'). Rep and Rep' are i...

  5. Transactional Literature Circles and the Reading Comprehension of English Learners in the Mainstream Classroom

    ERIC Educational Resources Information Center

    McElvain, Cheryl Marie

    2010-01-01

    This study examines a problem that many mainstream teachers face today: how to successfully improve reading comprehension for English language learners (ELLs) in an English-only environment. The researcher examines both the academic and psychosocial effects of the Transactional Literature Circles (TLC) programme on a treatment group of 75 fourth…

  6. Quality Circles. ERIC Highlights for School Administrators, May/June 1983.

    ERIC Educational Resources Information Center

    Lake, Sara

    Developed by Japanese corporations to improve productivity and product quality, quality circles (QC's) are small, voluntary groups of workers who share common job responsibilities and who meet regularly to generate solutions to problems. Features of QC's that are applicable to schools are examined in the nine articles summarized in this annotated…

  7. Youth Voter Turnout 1992 to 2004: Estimates from Exit Polls. CIRCLE Fact Sheet.

    ERIC Educational Resources Information Center

    Center for Information and Research on Civic Learning and Engagement, 2005

    2005-01-01

    CIRCLE has issued two releases estimating youth turnout in the 2004 presidential election. The first release was issued on November 3rd and provided the earliest turnout estimates based on National Election Pool (NEP) state and national exit polls and a preliminary vote count. The second was a Fact Sheet released on November 8th which provided…

  8. An Investigation of "Circle of Friends" Peer-Mediated Intervention for Students with Autism

    ERIC Educational Resources Information Center

    Schlieder, Mary; Maldonado, Nancy; Baltes, Beate

    2014-01-01

    The dramatic rise in children diagnosed with autism spectrum disorder (ASD) is accompanied by a substantial increase in public school inclusion. A growing body of research supports the need for teachers proficient in evidence-based practices to support such students. One strategy involves using peer support networks like Circle of Friends (CoF)…

  9. An Analysis of Elementary School Children's Fractional Knowledge Depicted with Circle, Rectangle, and Number Line Representations

    ERIC Educational Resources Information Center

    Tunç-Pekkan, Zelha

    2015-01-01

    It is now well known that fractions are difficult concepts to learn as well as to teach. Teachers usually use circular pies, rectangular shapes and number lines on the paper as teaching tools for fraction instruction. This article contributes to the field by investigating how the widely used three external graphical representations (i.e., circle,…

  10. Measuring the Impact of the Circle of Trust[R] Approach

    ERIC Educational Resources Information Center

    Smith, Janet

    2012-01-01

    Since the first Circle of Trust retreat was offered in 2005, the Center for Courage & Renewal (CCR) and other individual facilitators across the United States, Canada, and Australia have continued to offer many cross-professional retreats, as they have proven extremely popular. They are designed for people from any profession who want to…

  11. Dialing in to a Circle of Trust: A "Medium" Tech Experiment and Poetic Evaluation

    ERIC Educational Resources Information Center

    Love, Christine T.

    2012-01-01

    In his 2004 book "A Hidden Wholeness," Parker Palmer makes explicit the unique qualities of the transformational "circle of trust." He describes a group of people embracing the paradox of "being alone together," where the only goal of the group is to invite the emergence of the soul of each individual, through…

  12. Principles and Practices of the Circle of Trust[R] Approach

    ERIC Educational Resources Information Center

    Chadsey, Terry; Jackson, Marcy

    2012-01-01

    Through the Center for Courage & Renewal, the authors offer personal and professional retreats and programs designed to explore vocational and life questions, offer renewal and encouragement, and deepen engagement in professional practice. Using what they call the Circle of Trust[R] approach, they invite groups into a communal process based upon a…

  13. "Slow Down, You Move Too Fast:" Literature Circles as Reflective Practice

    ERIC Educational Resources Information Center

    Sanacore, Joseph

    2013-01-01

    Becoming an effective literacy learner requires a bit of slowing down and appreciating the reflective nature of reading and writing. Literature circles support this instructional direction because they provide opportunities for immersing students in discussions that encourage their personal responses. When students feel their personal responses…

  14. Facebook and Virtual Literature Circle Partnership in Building a Community of Readers

    ERIC Educational Resources Information Center

    Stewart, Paulette

    2009-01-01

    Social networks have given rise to a reading activity called an online literature circle. Generally from four to six students meet together in an online chat room to discuss the same reading. In this environment students engage in critical thinking and reflection as they read, discuss and respond to books. Collaboration is at the heart of this…

  15. Inquiry Circles as a Vehicle for Comprehending Informational Texts: Preservice Teachers' Reactions and Perceptions

    ERIC Educational Resources Information Center

    Diego-Medrano, Elsa; Coneway, Betty; Williams, Judy D.

    2016-01-01

    This study was conducted to explore teacher candidates' reactions and perceptions regarding their participation in inquiry circles and to discover how the experience influenced their comprehension of an informational text. The 98 teacher candidates involved in this study were enrolled in a children's literature course at a four-year university.…

  16. A Study of Traditional Circle Games Played in Public School Kindergartens across the United States.

    ERIC Educational Resources Information Center

    Rothlein, Liz; And Others

    1988-01-01

    Investigates traditional circle games played in 203 public school kindergartens in 35 states. Results indicate that music/movement and racing games were the major game categories; the most common frequency and duration was three times per week for 20 minutes; and the purposes of the games were to have fun, and to foster social, physical motor, and…

  17. Math Circles: A Tool for Promoting Engagement among Middle School Minority Males

    ERIC Educational Resources Information Center

    Kennedy, Eugene; Smolinsky, Lawrence

    2016-01-01

    This article presents results of a case study of a math circle designed for low income, minority students from an inner city middle school. The students were 6th, 7th and 8th grade African American and Hispanic males enrolled in a science, technology, engineering and mathematics focused charter school. The study focused on the impact of…

  18. New head equivalent phantom for task and image performance evaluation representative for neurovascular procedures occurring in the Circle of Willis

    NASA Astrophysics Data System (ADS)

    Ionita, Ciprian N.; Loughran, Brendan; Jain, Amit; Swetadri Vasan, S. N.; Bednarek, Daniel R.; Levy, Elad; Siddiqui, Adnan H.; Snyder, Kenneth V.; Hopkins, L. N.; Rudin, Stephen

    2012-03-01

    Phantom equivalents of different human anatomical parts are routinely used for imaging system evaluation or dose calculations. The various recommendations on the generic phantom structure given by organizations such as the AAPM, are not always accurate when evaluating a very specific task. When we compared the AAPM head phantom containing 3 mm of aluminum to actual neuro-endovascular image guided interventions (neuro-EIGI) occurring in the Circle of Willis, we found that the system automatic exposure rate control (AERC) significantly underestimated the x-ray parameter selection. To build a more accurate phantom for neuro-EIGI, we reevaluated the amount of aluminum which must be included in the phantom. Human skulls were imaged at different angles, using various angiographic exposures, at kV's relevant to neuro-angiography. An aluminum step wedge was also imaged under identical conditions, and a correlation between the gray values of the imaged skulls and those of the aluminum step thicknesses was established. The average equivalent aluminum thickness for the skull samples for frontal projections in the Circle of Willis region was found to be about 13 mm. The results showed no significant changes in the average equivalent aluminum thickness with kV or mAs variation. When a uniform phantom using 13 mm aluminum and 15 cm acrylic was compared with an anthropomorphic head phantom the x-ray parameters selected by the AERC system were practically identical. These new findings indicate that for this specific task, the amount of aluminum included in the head equivalent must be increased substantially from 3 mm to a value of 13 mm.

  19. Limits of the circles-in-the-sky searches in the determination of cosmic topology of nearly flat universes

    NASA Astrophysics Data System (ADS)

    Gomero, G. I.; Mota, B.; Rebouças, M. J.

    2016-08-01

    An important observable signature of a detectable nontrivial spatial topology of the Universe is the presence in the cosmic microwave background sky of pairs of matching circles with the same distributions of temperature fluctuations—the so-called circles in the sky. Most of the recent attempts to find these circles, including the ones undertaken by the Planck Collaboration, were restricted to antipodal or nearly antipodal circles with radii λ ≥1 5 ° . In the most general search, pairs of circles with deviation from antipodality angles 0 ° ≤θ ≤16 9 ° and radii 1 0 ° ≤λ ≤9 0 ° were investigated. No statistically significant pairs of matching circles were found in the searches so far undertaken. Assuming that the negative result of general search can be confirmed through analysis made with data from Planck and future cosmic microwave background experiments, we examine the question as to whether there are nearly flat universes with compact topology, satisfying Planck constraints on cosmological parameters, that would give rise to circles in the sky whose observable parameters λ and θ fall outside the parameter ranges covered by this general search. We derive the expressions for the deviation from antipodality and for the radius of the circles associated to a pair of elements (γ , γ-1 ) of the holonomy group Γ which define the spatial section of any positively curved universe with a nontrivial compact topology. We show that there is a critical position that maximizes the deviation from antipodality and prove that, no matter how nearly flat the Universe is, it can always have a nontrivial spatial topology that gives rise to circles whose deviation from antipodality θ is larger than 169° and whose radii of the circles λ are smaller than 10° for some observers's positions. This makes it apparent that slightly positively curved nearly flat universes with cosmological parameters within Planck bounds can be endowed with a nontrivial spatial

  20. NanoCluster Beacons as reporter probes in rolling circle enhanced enzyme activity detection.

    PubMed

    Juul, Sissel; Obliosca, Judy M; Liu, Cong; Liu, Yen-Liang; Chen, Yu-An; Imphean, Darren M; Knudsen, Birgitta R; Ho, Yi-Ping; Leong, Kam W; Yeh, Hsin-Chih

    2015-05-14

    As a newly developed assay for the detection of endogenous enzyme activity at the single-catalytic-event level, Rolling Circle Enhanced Enzyme Activity Detection (REEAD) has been used to measure enzyme activity in both single human cells and malaria-causing parasites, Plasmodium sp. Current REEAD assays rely on organic dye-tagged linear DNA probes to report the rolling circle amplification products (RCPs), the cost of which may hinder the widespread use of REEAD. Here we show that a new class of activatable probes, NanoCluster Beacons (NCBs), can simplify the REEAD assays. Easily prepared without any need for purification and capable of large fluorescence enhancement upon hybridization, NCBs are cost-effective and sensitive. Compared to conventional fluorescent probes, NCBs are also more photostable. As demonstrated in reporting the human topoisomerases I (hTopI) cleavage-ligation reaction, the proposed NCBs suggest a read-out format attractive for future REEAD-based diagnostics.

  1. Renaturation of complementary single-stranded DNA circles: complete rewinding facilitated by the DNA untwisting enzyme.

    PubMed Central

    Champoux, J J

    1977-01-01

    Renaturation of two complementary single-stranded circles should be limited by topological constraints against the rewinding of the DNA helix. If a mixture of complementary single-stranded rings is annealed and then treated with the DNA untwisting enzyme, the DNA circles completely renature as judged by (i) the presence of interlocked rings that sediment at 53 S in alkali, (ii) the buoyant density of the renatured DNA in CsCl gradients containing ethidium bromide, and (iii) the resistance of the product to the single-strand-specific S1 nuclease. Therefore, the DNA untwisting enzyme is able to provide a transient single-strand break that is sufficient to allow the two strands to completely rewind. The possibility that the untwisting enzyme might facilitate the initiation of the process of genetic recombination is discussed. PMID:202951

  2. Semi-automated identification of cones in the human retina using circle Hough transform

    PubMed Central

    Bukowska, Danuta M.; Chew, Avenell L.; Huynh, Emily; Kashani, Irwin; Wan, Sue Ling; Wan, Pak Ming; Chen, Fred K

    2015-01-01

    A large number of human retinal diseases are characterized by a progressive loss of cones, the photoreceptors critical for visual acuity and color perception. Adaptive Optics (AO) imaging presents a potential method to study these cells in vivo. However, AO imaging in ophthalmology is a relatively new phenomenon and quantitative analysis of these images remains difficult and tedious using manual methods. This paper illustrates a novel semi-automated quantitative technique enabling registration of AO images to macular landmarks, cone counting and its radius quantification at specified distances from the foveal center. The new cone counting approach employs the circle Hough transform (cHT) and is compared to automated counting methods, as well as arbitrated manual cone identification. We explore the impact of varying the circle detection parameter on the validity of cHT cone counting and discuss the potential role of using this algorithm in detecting both cones and rods separately. PMID:26713186

  3. Utilization of the concentric circle model in clinical nursing: a review.

    PubMed

    Kazuma, K

    1999-12-01

    In this article, I review applications of the concentric circle model in clinical nursing. The concentric circle model is based on the cross-sectional shape of the body extremities at several points, and can be used in the areas of both kinesiology and nutritional science. This model makes it possible to calculate the cross-sectional area of muscles from measurement of the circumference of the extremities and the thickness of adipose (fatty) tissue. Then, changes in muscle strength or nutritional status can be inferred or assessed from these data. This model requires only simple and non-invasive measurements, and this is a significant and essential characteristic for its use by nurses, both in clinical and research applications.

  4. Bells Galore: Oscillations and circle-map dynamics from space-filling fractal functions

    SciTech Connect

    Puente, C.E.; Cortis, A.; Sivakumar, B.

    2008-10-15

    The construction of a host of interesting patterns over one and two dimensions, as transformations of multifractal measures via fractal interpolating functions related to simple affine mappings, is reviewed. It is illustrated that, while space-filling fractal functions most commonly yield limiting Gaussian distribution measures (bells), there are also situations (depending on the affine mappings parameters) in which there is no limit. Specifically, the one-dimensional case may result in oscillations between two bells, whereas the two-dimensional case may give rise to unexpected circle map dynamics of an arbitrary number of two-dimensional circular bells. It is also shown that, despite the multitude of bells over two dimensions, whose means dance making regular polygons or stars inscribed on a circle, the iteration of affine maps yields exotic kaleidoscopes that decompose such an oscillatory pattern in a way that is similar to the many cases that converge to a single bell.

  5. Evaluating Quality Circles in U.S. Industry: A Feasibility Study.

    DTIC Science & Technology

    1982-06-30

    Mail Survey of IAQC Members APPENDIX B: May 1982 Survey of Readers of The Quality Circles Journal APPENDIX C: English- Language Questionnaires...34--- Questionnaire on General Work Conditions .Oq APPENDIX D: Japanese- Language Questionnaires: tj0 Questionnaire for Plait Administrator Questionnaire for Quality...A second concern by U.S. managers is whether the cause for the recent boom in Japanese productivity nay not be a function of other variables which

  6. Journeys of the Circle: a culturally congruent life skills intervention for adolescent Indian drinking.

    PubMed

    Marlatt, G Alan; Larimer, Mary E; Mail, Patricia D; Hawkins, Elizabeth H; Cummins, Lillian Huang; Blume, Arthur W; Lonczak, Heather S; Burns, Kelly M; Chan, Karen K; Cronce, Jessica M; La Marr, C June; Radin, Sandra; Forquera, Ralph; Gonzales, Rebecca; Tetrick, Crystal; Gallion, Steve

    2003-08-01

    There has been an increasing call for and development of culturally appropriate substance prevention/intervention for ethnic minorities in schools and communities, especially among reservation and in urban American Indian and Alaska Native (AIAN) communities. Past attempts to intervene in and reduce misuse of alcohol and other drugs have not had great success. The Journeys of the Circle Project utilized innovative programs with a strong emphasis on historic cultural traditions.

  7. Collective motion of humans in mosh and circle pits at heavy metal concerts.

    PubMed

    Silverberg, Jesse L; Bierbaum, Matthew; Sethna, James P; Cohen, Itai

    2013-05-31

    Human collective behavior can vary from calm to panicked depending on social context. Using videos publicly available online, we study the highly energized collective motion of attendees at heavy metal concerts. We find these extreme social gatherings generate similarly extreme behaviors: a disordered gaslike state called a mosh pit and an ordered vortexlike state called a circle pit. Both phenomena are reproduced in flocking simulations demonstrating that human collective behavior is consistent with the predictions of simplified models.

  8. Collective Motion of Humans in Mosh and Circle Pits at Heavy Metal Concerts

    NASA Astrophysics Data System (ADS)

    Silverberg, Jesse L.; Bierbaum, Matthew; Sethna, James P.; Cohen, Itai

    2013-05-01

    Human collective behavior can vary from calm to panicked depending on social context. Using videos publicly available online, we study the highly energized collective motion of attendees at heavy metal concerts. We find these extreme social gatherings generate similarly extreme behaviors: a disordered gaslike state called a mosh pit and an ordered vortexlike state called a circle pit. Both phenomena are reproduced in flocking simulations demonstrating that human collective behavior is consistent with the predictions of simplified models.

  9. The Astrophysical Signatures of Black Holes: The Horizon, The ISCO, The Ergosphere and The Light Circle

    NASA Astrophysics Data System (ADS)

    Abramowicz, Marek A.

    Three advanced instruments planned for a near future ( LOFT, GRAVITY, THE EVENT HORIZON TELESCOPE) provide unprecedented angular and time resolutions, which allow to probe regions in the immediate vicinity of black holes. We may soon be able to search for the signatures of the super-strong gravity that is characteristic to black holes: the event horizon, the ergosphere, the innermost stable circular orbit (ISCO), and the photon circle. This review discusses a few fundamental problems concerning these theoretical concepts.

  10. CircleRides: developing an older adult transportation application and evaluating feedback.

    PubMed

    Heinz, Melinda; Kelly, Norene

    2015-05-01

    The purpose of the current study was to assess perceptions of CircleRides, a paper prototype of a service website designed to meet older adult transportation needs. Researchers used purposive sampling to conduct two focus groups comprised of older adults to obtain feedback on the CircleRides prototype at the beginning of its iterative design process. One focus group was conducted in a continuing care retirement community (n = 13) and the other in an independent living community for older adults (n = 11). The study assessed perceptions of the CircleRides prototype as well as self-reported older adult transportation preferences and needs. Three themes emerged from the data: (a) trust and concern, (b) socialization, and (c) flexibility and options. Researchers found that participants are interested in transportation options; however, concern exists about trusting a new system or prototype that has not established a reputation. Findings from the current study offer lessons learned for future iterations and for creating transportation prototypes for older adults.

  11. Innovation in qualitative interviews: "Sharing Circles" in a First Nations community.

    PubMed

    Rothe, J P; Ozegovic, D; Carroll, L J

    2009-10-01

    There is growing recognition that different research approaches are necessary to understand the complex interaction between individual and social processes that contribute to risk-taking and injuries. Therefore, qualitative studies have an important role in injury prevention research. This article describes qualitative research in general and outlines some of the ways qualitative research can add to our understanding of injury. It also describes the role, format and methods of interviews (person-to-person and focus groups) commonly performed in qualitative studies, and proposes a novel approach to interviewing that has special relevance and value in injury research with indigenous populations. This methodology adapts focus group methods to be consistent with the goals and procedures of the traditional First Nations communities' Sharing Circles. This adaptation provides a culturally appropriate and sensitive method of developing a deep and broad understanding of indigenous participants' verbal descriptions of their feelings, their experiences and their modes of reasoning. After detailing of this adaptation of the Sharing Circle as a vibrant and vital interview and analysis method, the use of Sharing Circle interview methodology will be illustrated in a study investigating how an Alberta First Nations community experiences and deals with disproportionate levels of injuries arising from impaired driving, outlining important findings uncovered using this novel interviewing method. These findings have been informative to First Nations communities themselves, have informed policy makers provincially and nationally, and have instigated culturally appropriate intervention techniques for Canadian First Nations communities.

  12. Amplitude variables of circle on the pedagogic pommel horse in gymnastics.

    PubMed

    Baudry, Ludovic; Sforza, Chiarella; Leroy, David; Lovecchio, Nicola; Gautier, Geoffroy; Thouvarecq, Régis

    2009-05-01

    The movement amplitude is a key component of numerous elements in gymnastics. The purpose of the present study is to highlight the most pertinent amplitude variable of the circle performed on the pedagogic pommel horse. Twelve gymnasts (6 expert gymnasts vs. 6 nonexpert gymnasts) performed 10 circles on this event. A Vicon 512 system was used to record the 3-dimensional position of 11 markers fixed on the gymnasts. Our results revealed than 4 amplitude variables permitted us to significantly discriminate the levels of performance of the gymnasts (p < 0.05): shoulder extension in front phase, body alignment, shoulder diameter, and ankle diameter. In a training perspective, this result could help coaches focus their advice and pedagogic situations on the pertinent technical criteria. Then, a stepwise discriminant analysis performed on the 4 previously selected variables showed that 2 variables allowed us to accurately discriminate the circle amplitude: ankle diameter and body alignment. These 2 variables can be used by coaches as a specific index to objectively determine the performance levels of gymnasts and to measure improvement in movements after specific training.

  13. Random covering of the circle: the configuration-space of the free deposition process

    NASA Astrophysics Data System (ADS)

    Huillet, Thierry

    2003-12-01

    Consider a circle of circumference 1. Throw at random n points, sequentially, on this circle and append clockwise an arc (or rod) of length s to each such point. The resulting random set (the free gas of rods) is a collection of a random number of clusters with random sizes. It models a free deposition process on a 1D substrate. For such processes, we shall consider the occurrence times (number of rods) and probabilities, as n grows, of the following configurations: those avoiding rod overlap (the hard-rod gas), those for which the largest gap is smaller than rod length s (the packing gas), those (parking configurations) for which hard rod and packing constraints are both fulfilled and covering configurations. Special attention is paid to the statistical properties of each such (rare) configuration in the asymptotic density domain when ns = rgr, for some finite density rgr of points. Using results from spacings in the random division of the circle, explicit large deviation rate functions can be computed in each case from state equations. Lastly, a process consisting in selecting at random one of these specific equilibrium configurations (called the observable) can be modelled. When particularized to the parking model, this system produces parking configurations differently from Rényi's random sequential adsorption model.

  14. White Blood Cell Segmentation by Circle Detection Using Electromagnetism-Like Optimization

    PubMed Central

    Oliva, Diego; Díaz, Margarita; Zaldivar, Daniel; Pérez-Cisneros, Marco; Pajares, Gonzalo

    2013-01-01

    Medical imaging is a relevant field of application of image processing algorithms. In particular, the analysis of white blood cell (WBC) images has engaged researchers from fields of medicine and computer vision alike. Since WBCs can be approximated by a quasicircular form, a circular detector algorithm may be successfully applied. This paper presents an algorithm for the automatic detection of white blood cells embedded into complicated and cluttered smear images that considers the complete process as a circle detection problem. The approach is based on a nature-inspired technique called the electromagnetism-like optimization (EMO) algorithm which is a heuristic method that follows electromagnetism principles for solving complex optimization problems. The proposed approach uses an objective function which measures the resemblance of a candidate circle to an actual WBC. Guided by the values of such objective function, the set of encoded candidate circles are evolved by using EMO, so that they can fit into the actual blood cells contained in the edge map of the image. Experimental results from blood cell images with a varying range of complexity are included to validate the efficiency of the proposed technique regarding detection, robustness, and stability. PMID:23476713

  15. Effects of Local Configuration on the Flow in the Circle of Willis

    NASA Astrophysics Data System (ADS)

    Page, J. H.; Wu, G. X.; Smith, F. T.

    The circle of Willis is a confluence of large arteries which form a ring-like, three-to-six junction. The right and left internal carotid arteries and the basilar artery carry blood up the neck and meet a circular arrangement of three communicating arteries at the base of the cerebrum. Six cerebral arteries then depart from the circle of Willis towards different areas of the brain. The circle of Willis plays a pivotal role in allowing the correct blood distribution in the cerebrum. The presence of the communicating arteries provides routes along which blood may flow in order to moderate or effect changes in the efferent flux distribution, in response to variations in the supply of and local demands for blood[1]. The anterior communicating artery is a common site for the occurrence of cerebral aneurysms, an abnormal bulge in the arterial wall which grows over time [2]. Such cerebral aneurysms can eventually rupture leading to a subarachnoid haemorrhage [2]. It is widely thought that forces exerted by the blood on the arterial wall, such as wall pressure and wall shear stress, make a significant contribution to the growth of aneurysms [3].

  16. Hydraulic characteristics of an underdrained irrigation circle, Muskegon County, wastewater disposal system, Michigan

    USGS Publications Warehouse

    McDonald, M.G.

    1981-01-01

    Muskegon County, Michigan, disposes of waste water by spray irrigating farmland on its waste-disposal site. Buried drains in the highly permeable unconfined aquifer at the site control the level of the water table. Hydraulic conductivity of the aquifer and drain-leakance, the reciprocal of resistance to flow into the drains, was determined at a representative irrigation circle while calibrating a model of the ground-water flow system. Hydraulic conductivity is 0.00055 meter per second in the north zone of the circle and 0.00039 meter per second in the south zone. Drain leakance is low in both zones: 2.9 x 10-6 meters per second in the north and 9.5 x 10-6 meters per second in the south. Low drain leakance is responsible for waterlogging when irrigation rates are maintained at design levels. The capacity of the study circle to accept waste water is 35 percent less than design capacity.

  17. Impact of a learning circle intervention across academic and service contexts on developing a learning culture.

    PubMed

    Walker, Rachel; Henderson, Amanda; Cooke, Marie; Creedy, Debra

    2011-05-01

    Partnerships between university schools of nursing and health services lead to successful learning experiences for students and staff. A purposive sample of academics and students from a university school of nursing and clinicians from three health institutions involved in clinical learning (n=73) actively participated in a learning circles intervention conducted over 5 months in south east Queensland. Learning circle discussions resulted in enhanced communication and shared understanding regarding: (1) staff attitudes towards students, expectations and student assessment; (2) strategies enhancing preparation of students, mechanisms for greater support of and recognition of clinicians; (3) challenges faced by staff in the complex processes of leadership in clinical nursing education; (4) construction of learning, ideas for improving communication, networking and sharing; and (5) questioning routine practices that may not enhance student learning. Pre-post surveys of hospital staff (n=310) revealed significant differences across three sub-scales of 'accomplishment' (t=-3.98, p<.001), 'recognition' (t=-2.22, p<.027) and 'influence' (t=-11.82, p<.001) but not 'affiliation'. Learning circles can positively enhance organisational learning culture. The intervention enabled participants to recognise mutual goals. Further investigation around staff perception of their influence on their workplace is required.

  18. Planning Curvature-Constrained Paths to Multiple Goals Using Circle Sampling.

    PubMed

    Lobaton, Edgar; Zhang, Jinghe; Patil, Sachin; Alterovitz, Ron

    2011-01-01

    We present a new sampling-based method for planning optimal, collision-free, curvature-constrained paths for nonholonomic robots to visit multiple goals in any order. Rather than sampling configurations as in standard sampling-based planners, we construct a roadmap by sampling circles of constant curvature and then generating feasible transitions between the sampled circles. We provide a closed-form formula for connecting the sampled circles in 2D and generalize the approach to 3D workspaces. We then formulate the multi-goal planning problem as finding a minimum directed Steiner tree over the roadmap. Since optimally solving the multi-goal planning problem requires exponential time, we propose greedy heuristics to efficiently compute a path that visits multiple goals. We apply the planner in the context of medical needle steering where the needle tip must reach multiple goals in soft tissue, a common requirement for clinical procedures such as biopsies, drug delivery, and brachytherapy cancer treatment. We demonstrate that our multi-goal planner significantly decreases tissue that must be cut when compared to sequential execution of single-goal plans.

  19. Planning Curvature-Constrained Paths to Multiple Goals Using Circle Sampling

    PubMed Central

    Lobaton, Edgar; Zhang, Jinghe; Patil, Sachin; Alterovitz, Ron

    2011-01-01

    We present a new sampling-based method for planning optimal, collision-free, curvature-constrained paths for nonholonomic robots to visit multiple goals in any order. Rather than sampling configurations as in standard sampling-based planners, we construct a roadmap by sampling circles of constant curvature and then generating feasible transitions between the sampled circles. We provide a closed-form formula for connecting the sampled circles in 2D and generalize the approach to 3D workspaces. We then formulate the multi-goal planning problem as finding a minimum directed Steiner tree over the roadmap. Since optimally solving the multi-goal planning problem requires exponential time, we propose greedy heuristics to efficiently compute a path that visits multiple goals. We apply the planner in the context of medical needle steering where the needle tip must reach multiple goals in soft tissue, a common requirement for clinical procedures such as biopsies, drug delivery, and brachytherapy cancer treatment. We demonstrate that our multi-goal planner significantly decreases tissue that must be cut when compared to sequential execution of single-goal plans. PMID:22294101

  20. Ixodes ricinus and Borrelia prevalence at the Arctic Circle in Norway.

    PubMed

    Hvidsten, Dag; Stuen, Snorre; Jenkins, Andrew; Dienus, Olaf; Olsen, Renate S; Kristiansen, Bjørn-Erik; Mehl, Reidar; Matussek, Andreas

    2014-03-01

    The distribution limit of Ixodes ricinus ticks in northwestern Europe (Brønnøy, Norway, 1° south of the Arctic Circle), has been known since the 1930s. To reconfirm this finding and extend studies in the areas adjacent to the Arctic Circle (66°33' N), ticks were collected from dogs and cats in 8 districts in northern Norway from 64°56' N to 68°48' N. We detected 549 I. ricinus, 244 (44%) of them in Brønnøy district, and 305 (range 6-87 ticks) in 7 districts in the northern part of the study area. The prevalence of Borrelia in these ticks was determined by real-time PCR. In the Brønnøy district (65°28' N, 12°12' E), 29% of the I. ricinus were Borrelia spp.-positive, and the species B. afzelii was nearly twice as prevalent as B. garinii and/or B. valaisiana. In the study area north of Brønnøy district, only 12 (4%) of the collected ticks contained Borrelia spp. In conclusion, tick occurrence and Borrelia prevalence are high in the Brønnøy district. In contrast, I. ricinus occurrence and Borrelia prevalence are low further north across the Arctic Circle in Norway.

  1. A U.K. cost-benefit analysis of circles of support and accountability interventions.

    PubMed

    Elliott, Ian A; Beech, Anthony R

    2013-06-01

    Circles of Support and Accountability (CoSA) aim to augment sex offender risk management at the point of community reentry by facilitating "Circles" of volunteers who provide support, guidance, and advice, while ensuring that the offender remains accountable for their actions. In this study, the authors provide (a) a rapid evidence assessment of the effectiveness of CoSA in reducing reoffending, and (b) a U.K. cost-benefit analysis for CoSA when compared to the criminal justice costs of reoffending. From the study analysis, the average cost of a "Circle" was estimated to be £11,303 per annum and appears to produce a 50% reduction in reoffending (sexual and nonsexual), as the estimated cost of reoffending was estimated to be £147,161 per offender, per annum. Based on a hypothetical cohort of 100 offenders--50 of whom receive CoSA and 50 of whom do not--investment in CoSA appears to provide a cost saving of £23,494 and a benefit-cost ratio of 1.04. Accounting for estimates that the full extent of the cost to society may be 5 to 10 times the tangible costs substantially increases estimated cost savings related to CoSA.

  2. Adaptive circle-ellipse fitting method for estimating tree diameter based on single terrestrial laser scanning

    NASA Astrophysics Data System (ADS)

    Bu, Guochao; Wang, Pei

    2016-04-01

    Terrestrial laser scanning (TLS) has been used to extract accurate forest biophysical parameters for inventory purposes. The diameter at breast height (DBH) is a key parameter for individual trees because it has the potential for modeling the height, volume, biomass, and carbon sequestration potential of the tree based on empirical allometric scaling equations. In order to extract the DBH from the single-scan data of TLS automatically and accurately within a certain range, we proposed an adaptive circle-ellipse fitting method based on the point cloud transect. This proposed method can correct the error caused by the simple circle fitting method when a tree is slanted. A slanted tree was detected by the circle-ellipse fitting analysis, then the corresponding slant angle was found based on the ellipse fitting result. With this information, the DBH of the trees could be recalculated based on reslicing the point cloud data at breast height. Artificial stem data simulated by a cylindrical model of leaning trees and the scanning data acquired with the RIEGL VZ-400 were used to test the proposed adaptive fitting method. The results shown that the proposed method can detect the trees and accurately estimate the DBH for leaning trees.

  3. Over-expression of myosin7A in cochlear hair cells of circling mice

    PubMed Central

    Kim, Yoo Yeon; Nam, Hajin; Jung, Harry; Kim, Boyoung

    2017-01-01

    Circling mouse (C57BL/6J-cir/cir) deleted the transmembrane inner ear (Tmie) gene is an animal model for human non-syndromic recessive deafness, DFNB6. In circling mouse, hair cells in the cochlea have degenerated and hair bundles have become irregularity as time goes on. Tmie protein carries out a function of the mechanoelectrical transduction channel in cochlear hair cells. Myosin7a (MYO7A) protein has key roles in development of the cochlear hair bundles as well as in the function of cochlear hair cells. To find whether Tmie protein interacts with MYO7A proteins in the cochlea postnatal developmental stage, we investigated expression of the MYO7A proteins in the cochlear hair cells of circling mice by western blot analysis and whole mount immunofluorescence at postnatal day 5 (P5). The expression of MYO7A showed statistically significant increase in the cochlea of C57BL/6J-+/cir and C57BL/6J-cir/cir mice than that of C57BL/6J-+/+ mice. The MYO7A intensity of the cochlear hair cells also increased in C57BL/6J-+/cir and C57BL/6J-cir/cir mice compared with those of C57BL/6J-+/+ mice. Taken together, the results indicate that Tmie protein may have an important role with MYO7A protein in the development and maintenance of the stereociliary bundles during postnatal developmental stage of the cochlea.

  4. On Möbius orthogonality for interval maps of zero entropy and orientation-preserving circle homeomorphisms

    NASA Astrophysics Data System (ADS)

    Karagulyan, Davit

    2015-10-01

    We will prove Sarnak's conjecture on Möbius disjointness for continuous interval maps of zero entropy and also for orientation-preserving circle homeomorphisms by reducing these result to a well-known theorem of Davenport from 1937.

  5. "Really," "Not Possible," "I Can't Believe It": Exploring Informational Text in Literature Circles

    ERIC Educational Resources Information Center

    Barone, Diane; Barone, Rebecca

    2016-01-01

    Fifth graders' interpretations of nonfiction or informational text were explored. Each literature circle group read and responded to informational text. Discoveries included that students' conversations and written responses were closely connected to text and that students created multimodal responses.

  6. Quality Circles

    DTIC Science & Technology

    1990-04-09

    spread rapidly through many major Japanese firms. In 1962, Dr. Kaoru Ishikawa tied these new quality control methods to the theories of Maslow , Herzberg...should be on people solving problems and not on hierarchical pyramids of paperwork. 21 6. Management must learn how to positively reinforce participative

  7. Analysis of pMA67, a predicted rolling-circle replicating, mobilizable, tetracycline-resistance plasmid from the honey bee pathogen, Paenibacillus larvae.

    PubMed

    Murray, K Daniel; Aronstein, Katherine A; de León, Jesse H

    2007-09-01

    This work characterizes a recently discovered natural tetracycline-resistance plasmid called pMA67 from Paenibacillus larvae--a Gram-positive bacterial pathogen of honey bees. We provide evidence that pMA67 replicates by the rolling-circle mechanism, and sequence comparisons place it in the pMV158 family of rolling-circle replicons. The plasmid contains predicted rep, cop, and rnaII genes for control of replication initiating at a predicted double-strand origin. The plasmid has an ssoT single-strand origin, which is efficient enough to allow only very small amounts of the single-stranded DNA intermediate to accumulate. The overall efficiency of replication is sufficient to render the plasmid segregationally stable without selection in P. larvae and in Bacillus megaterium, but not in Escherichia coli. The plasmid is expected to be mobilizable due to the presence of a mob gene and an oriT site. The plasmid contains a tetL gene, whose predicted amino acid sequence implies a relatively ancient divergence from all previously known plasmid-encoded tetL genes. We confirm that the tetL gene alone is sufficient for conferring resistance to tetracyclines. Sequence comparisons, mostly with the well-characterized pMV158, allow us to predict promoters, DNA and RNA secondary structures, DNA and protein motifs, and other elements.

  8. Action-Oriented Study Circles Facilitate Efforts in Nursing Homes to “Go from Feeding to Serving”: Conceptual Perspectives on Knowledge Translation and Workplace Learning

    PubMed Central

    Westergren, Albert

    2012-01-01

    Background. Action-oriented study circles (AOSC) have been found to improve nutrition in 24 nursing homes in Sweden. Little, however, is known about the conceptual use of knowledge (changes in staffs' knowledge and behaviours). Methods. Qualitative and quantitative methods, structured questionnaires for evaluating participants' (working in nursing homes) experiences from study circles (n = 592, 71 AOSC) and for comparisons between AOSC participants (n = 74) and nonparticipants (n = 115). Finally, a focus group interview was conducted with AOSC participants (in total n = 12). Statistical, conventional, and directed content analyses were used. Results. Participants experienced a statistically significant increase in their knowledge about eating and nutrition, when retrospectively comparing before participating and after, as well as in comparison to non-participants, and they felt that the management was engaged in and took care of ideas regarding food and mealtimes to a significantly greater extent than non-participants. The use of AOSC was successful judging from how staff members had changed their attitudes and behaviours toward feeding residents. Conclusions. AOSC facilitates professional development, better system performance, and, as shown in previous studies, better patient outcome. Based on a collaborative learning perspective, AOSC manages to integrate evidence, context, and facilitation in the efforts to achieve knowledge translation in a learning organisation. This study has implications also for other care settings implementing AOSC. PMID:22991666

  9. Squaring the circle? Combining models, indicators, experts and end-users in integrated land-use management support tools.

    PubMed

    Fürst, Christine; Volk, Martin; Makeschin, Franz

    2010-12-01

    The most important challenges faced in the field of integrated land-use management are (i) harmonizing and integrating different datasets, (ii) selecting appropriate indicators, (iii) fitting suitable models to adequate scales, and finally (iv) integrating data, indicators and models into systems that allow both a high level of participation and flexibility with the adaptation to a variety of questions and applications. The articles of this special issue "Squaring the Circle? Combining Models, Indicators, Experts and End-Users in Integrated Land-Use Management Support Tools" demonstrate the challenges that are related to this topic. The case studies present examples of such integrated systems in order to recommend best practices to support land-use management and to reveal existing shortcomings. As a conclusion, seven features of a successful applicable integrated land-use management support system are derived: (1) ability to deal with discontinuity in information and datasets, (2) contribution to solve the problem of indicator diversity, (3) structuring the decision-making process, (4) support of participation processes in generating decisions, (5) development, comparison and evaluation of land-use alternatives, (6) assessment of the efficiency and trade-offs of management options, and (7) assistance of stakeholders in group communication processes.

  10. Graphical Data Analysis on the Circle: Wrap-Around Time Series Plots for (Interrupted) Time Series Designs.

    PubMed

    Rodgers, Joseph Lee; Beasley, William Howard; Schuelke, Matthew

    2014-01-01

    Many data structures, particularly time series data, are naturally seasonal, cyclical, or otherwise circular. Past graphical methods for time series have focused on linear plots. In this article, we move graphical analysis onto the circle. We focus on 2 particular methods, one old and one new. Rose diagrams are circular histograms and can be produced in several different forms using the RRose software system. In addition, we propose, develop, illustrate, and provide software support for a new circular graphical method, called Wrap-Around Time Series Plots (WATS Plots), which is a graphical method useful to support time series analyses in general but in particular in relation to interrupted time series designs. We illustrate the use of WATS Plots with an interrupted time series design evaluating the effect of the Oklahoma City bombing on birthrates in Oklahoma County during the 10 years surrounding the bombing of the Murrah Building in Oklahoma City. We compare WATS Plots with linear time series representations and overlay them with smoothing and error bands. Each method is shown to have advantages in relation to the other; in our example, the WATS Plots more clearly show the existence and effect size of the fertility differential.

  11. Curved grating fabrication techniques for concentric-circle grating, surface-emitting semiconductor lasers

    NASA Technical Reports Server (NTRS)

    Jordan, Rebecca H.; King, Oliver; Wicks, Gary W.; Hall, Dennis G.; Anderson, Erik H.; Rooks, Michael J.

    1993-01-01

    We describe the fabrication and operational characteristics of a novel, surface-emitting semiconductor laser that makes use of a concentric-circle grating to both define its resonant cavity and to provide surface emission. A properly fabricated circular grating causes the laser to operate in radially inward- and outward-going circular waves in the waveguide, thus, introducing the circular symmetry needed for the laser to emit a beam with a circular cross-section. The basic circular-grating-resonator concept can be implemented in any materials system; an AlGaAs/GaAs graded-index, separate confinement heterostructure (GRINSCH), single-quantum-well (SQW) semiconductor laser, grown by molecular beam epitaxy (MBE), was used for the experiments discussed here. Each concentric-circle grating was fabricated on the surface of the AlGaAs/GaAs semiconductor laser. The circular pattern was first defined by electron-beam (e-beam) lithography in a layer of polymethylmethacrylate (PMMA) and subsequently etched into the semiconductor surface using chemically-assisted (chlorine) ion-beam etching (CAIBE). We consider issues that affect the fabrication and quality of the gratings. These issues include grating design requirements, data representation of the grating pattern, and e-beam scan method. We provide examples of how these techniques can be implemented and their impact on the resulting laser performance. A comparison is made of the results obtained using two fundamentally different electron-beam writing systems. Circular gratings with period lambda = 0.25 microns and overall diameters ranging from 80 microns to 500 microns were fabricated. We also report our successful demonstration of an optically pumped, concentric-circle grating, semiconductor laser that emits a beam with a far-field divergence angle that is less than one degree. The emission spectrum is quite narrow (less than 0.1 nm) and is centered at wavelength lambda = 0.8175 microns.

  12. Uniform circular motion concept attainment through circle share learning model using real media

    NASA Astrophysics Data System (ADS)

    Ponimin; Suparmi; Sarwanto; Sunarno, W.

    2017-01-01

    Uniform circular motion is an important concept and has many applications in life. Student’s concept understanding of uniform circular motion is not optimal because the teaching learning is not carried out properly in accordance with the characteristics of the concept. To improve student learning outcomes required better teaching learning which is match with the characteristics of uniform circular motion. The purpose of the study is to determine the effect of real media and circle share model to the understanding of the uniform circular motion concept. The real media was used to visualize of uniform circular motion concept. The real media consists of toy car, round table and spring balance. Circle share model is a learning model through discussion sequentially and programmed. Each group must evaluate the worksheets of another group in a circular position. The first group evaluates worksheets the second group, the second group evaluates worksheets third group, and the end group evaluates the worksheets of the first group. Assessment of learning outcomes includes experiment worksheets and post-test of students. Based on data analysis we obtained some findings. First, students can explain the understanding of uniform circular motion whose angular velocity and speed is constant correctly. Second, students can distinguish the angular velocity and linear velocity correctly. Third, students can explain the direction of the linear velocity vector and the direction of the centripetal force vector. Fourth, the student can explain the influence of the mass, radius, and velocity toward the centripetal force. Fifth, students can explain the principle of combined of wheels. Sixth, teaching learning used circle share, can increase student activity, experimental results and efficiency of discussion time.

  13. An Exploration of Social Circles and Prescription Drug Abuse Through Twitter

    PubMed Central

    2013-01-01

    Background Prescription drug abuse has become a major public health problem. Relationships and social context are important contributing factors. Social media provides online channels for people to build relationships that may influence attitudes and behaviors. Objective To determine whether people who show signs of prescription drug abuse connect online with others who reinforce this behavior, and to observe the conversation and engagement of these networks with regard to prescription drug abuse. Methods Twitter statuses mentioning prescription drugs were collected from November 2011 to November 2012. From this set, 25 Twitter users were selected who discussed topics indicative of prescription drug abuse. Social circles of 100 people were discovered around each of these Twitter users; the tweets of the Twitter users in these networks were collected and analyzed according to prescription drug abuse discussion and interaction with other users about the topic. Results From November 2011 to November 2012, 3,389,771 mentions of prescription drug terms were observed. For the 25 social circles (n=100 for each circle), on average 53.96% (SD 24.3) of the Twitter users used prescription drug terms at least once in their posts, and 37.76% (SD 20.8) mentioned another Twitter user by name in a post with a prescription drug term. Strong correlation was found between the kinds of drugs mentioned by the index user and his or her network (mean r=0.73), and between the amount of interaction about prescription drugs and a level of abusiveness shown by the network (r=0.85, P<.001). Conclusions Twitter users who discuss prescription drug abuse online are surrounded by others who also discuss it—potentially reinforcing a negative behavior and social norm. PMID:24014109

  14. Two-photon microscopy with double-circle trajectories for in vivo cerebral blood flow measurements

    NASA Astrophysics Data System (ADS)

    Landolt, Andrin; Obrist, Dominik; Wyss, Matthias; Barrett, Matthew; Langer, Dominik; Jolivet, Renaud; Soltysinski, Tomasz; Roesgen, Thomas; Weber, Bruno

    2013-05-01

    Scanning microscopes normally use trajectories which produce full-frame images of an object at a low frame rate. Time-resolved measurements are possible if scans along a single line are repeated at a high rate. In conjunction with fluorescence labeling techniques, in vivo recording of blood flow in single capillaries is possible. The present work investigates scanning with double-circle trajectories to measure blood flow simultaneously in several vessels of a capillary network. With the trajectory centered near a bifurcation, a double circle crosses each vessel twice, creating a sensing gate for passing dark red blood cells in fluorescently labeled plasma. From the stack of scans repeated at 1,300 Hz, the time-resolved velocity is retrieved using an image correlation approach. Single bifurcation events can be identified from a few fluorescently labeled red blood cells. The applicability of the method for in vivo measurements is illustrated on the basis of two-photon laser scanning microscopy of the cerebral capillary network of mice. Its performance is assessed with synthetic data generated from a two-phase model for the perfusion in a capillary network. The calculation of velocities is found to be sufficiently robust for a wide range of conditions. The achievable limits depend significantly on the experimental conditions and are estimated to be in the 1 μm/s (velocity) and 0.1 s (time resolution) ranges, respectively. Some manual fine-tuning is required for optimal performance in terms of accuracy and time resolution. Further work may lead to improved reliability with which bifurcation events are identified in the algorithm and to include red blood cell flux and hematocrit measurements. With the capability for time-resolved measurements in all vessels of a bifurcation, double-circle scanning trajectories allow a detailed study of the dynamics in vascular networks.

  15. Crustal Strike-Slip Faulting along Small Circle Paths in the Northwestern United States

    NASA Astrophysics Data System (ADS)

    Brocher, T. M.; Wells, R. E.; Lamb, A. P.; Weaver, C. S.

    2015-12-01

    Late Cenozoic and Quaternary faults, seismicity lineaments, and focal mechanisms provide evidence that clockwise rotation of Washington and Oregon is accommodated by north-directed thrusting and strike-slip deformation in the Washington segment of the Cascadia forearc. Curvilinear NW- to NNW-trending high-angle strike-slip faults and seismicity lineaments define small circles around an Euler pole (117.7°W, 47.9°N) of rotation relative to North America that approximates GPS-derived poles for the rotation of eastern Washington and the Snake River Plain. Although the lengths of strike-slip faults that follow small circle paths suggest maximum earthquake magnitudes of M6.6 to M7.2, their slip rates calculated from the Euler pole are low (0.3 to 0.5 mm/yr). Many normal faults in the Lewis and Clark Zone in Montana, the Centennial fault system north of the Snake River Plain, west of the Wasatch Front, in the northern Basin and Range, and locally east of the Oregon Cascade arc are radial to this pole of rotation, suggesting that these normal faults help accommodate this crustal rotation. Regions undergoing contraction in western Washington and northwestern Oregon are separated from those to the east undergoing extension by lines radial to the Euler pole. In our regional kinematic model, dextral faults along small circles connect SW-directed crustal extension in the Intermountain Seismic Belt and E-directed extension in the Cascade arc south of Mount Hood to N-directed contraction in the Olympic Peninsula, Puget Lowland, and the Yakima Fold and Thrust Belt. The lack of Quaternary faulting and seismicity in the Oregon segment of the forearc is consistent with its clockwise rotation as a rigid block. Potential drivers of the crustal rotation include westward slab rollback and the Yellowstone geoid high, and the overall velocity field may integrate the response of rotating blocks and distributed deformation between them.

  16. 3-D RESERVOIR AND STOCHASTIC FRACTURE NETWORK MODELING FOR ENHANCED OIL RECOVERY, CIRCLE RIDGE PHOSPHORIA/TENSLEEP RESERVOIR, WIND RIVER RESERVATION, ARAPAHO AND SHOSHONE TRIBES, WYOMING

    SciTech Connect

    Paul La Pointe; Jan Hermanson; Robert Parney; Thorsten Eiben; Mike Dunleavy; Ken Steele; John Whitney; Darrell Eubanks; Roger Straub

    2002-11-18

    This report describes the results made in fulfillment of contract DE-FG26-00BC15190, ''3-D Reservoir and Stochastic Fracture Network Modeling for Enhanced Oil Recovery, Circle Ridge Phosphoria/Tensleep Reservoir, Wind River Reservation, Arapaho and Shoshone Tribes, Wyoming''. The goal of this project is to improve the recovery of oil from the Tensleep and Phosphoria Formations in 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. Fields in which natural fractures dominate reservoir permeability, such as the Circle Ridge Field, often experience sub-optimal recovery when recovery processes are designed and implemented that do not take advantage of the fracture systems. For example, a conventional waterflood in a main structural block of the Field was implemented and later suspended due to unattractive results. It is estimated that somewhere less than 20% of the OOIP in the Circle Ridge Field have been recovered after more than 50 years' production. Marathon Oil Company identified the Circle Ridge Field as an attractive candidate for several advanced IOR processes that explicitly take advantage of the natural fracture system. These processes require knowledge of the distribution of matrix porosity, permeability and oil saturations; and understanding of where fracturing is likely to be well-developed or poorly developed; how the fracturing may compartmentalize the reservoir; and how smaller, relatively untested subthrust fault blocks may be connected to the main overthrust block. For this reason, the project focused on improving knowledge of the matrix properties, the fault block architecture and to develop a model that could be used to predict fracture intensity, orientation and fluid flow/connectivity properties. Knowledge of matrix properties was

  17. [Capoeira circle or sports academy? The emergence of modern styles of capoeira and their global context].

    PubMed

    Assunção, Matthias Röhrig

    2014-01-01

    The emergence of the modern styles of capoeira should be considered in the global context of the modernization of martial arts currently in progress in Europe and Asia on the one hand, and the new phase of Afro-descendant modernity on the other. The confrontation between the capoeira, jiu-jitsu and other martial arts circles led mestre Bimba to develop his regional Bahian fighting style. The revival of traditional capoeira as Angolan capoeira led by mestre Pastinha is part of the broader movement of affirmation of Afro-Bahian culture in Salvador and the growing visibility of the Afro-descendant body in the Atlantic world.

  18. Aircraft Detection from VHR Images Based on Circle-Frequency Filter and Multilevel Features

    PubMed Central

    Gao, Feng; Li, Bo

    2013-01-01

    Aircraft automatic detection from very high-resolution (VHR) images plays an important role in a wide variety of applications. This paper proposes a novel detector for aircraft detection from very high-resolution (VHR) remote sensing images. To accurately distinguish aircrafts from background, a circle-frequency filter (CF-filter) is used to extract the candidate locations of aircrafts from a large size image. A multi-level feature model is then employed to represent both local appearance and spatial layout of aircrafts by means of Robust Hue Descriptor and Histogram of Oriented Gradients. The experimental results demonstrate the superior performance of the proposed method. PMID:24163637

  19. Circum-Arctic Resource Appraisal: Estimates of Undiscovered Oil and Gas North of the Arctic Circle

    USGS Publications Warehouse

    Bird, Kenneth J.; Charpentier, Ronald R.; Gautier, Donald L.; Houseknecht, David W.; Klett, Timothy R.; Pitman, Janet K.; Moore, Thomas E.; Schenk, Christopher J.; Tennyson, Marilyn E.; Wandrey, Craig R.

    2008-01-01

    The U.S. Geological Survey (USGS) has completed an assessment of undiscovered conventional oil and gas resources in all areas north of the Arctic Circle. Using a geology-based probabilistic methodology, the USGS estimated the occurrence of undiscovered oil and gas in 33 geologic provinces thought to be prospective for petroleum. The sum of the mean estimates for each province indicates that 90 billion barrels of oil, 1,669 trillion cubic feet of natural gas, and 44 billion barrels of natural gas liquids may remain to be found in the Arctic, of which approximately 84 percent is expected to occur in offshore areas.

  20. On Combinatorial Analogs of the Group of Diffeomorphisms of the Circle

    NASA Astrophysics Data System (ADS)

    Neretin, Yu A.

    1993-04-01

    The goal of this article is to construct and study groups which, from the point of view of the theory of representations, should resemble the group of diffeomorphisms of the circle. The first type of such groups are the diffeomorphism groups of p-adic projective lines. The second type are groups consisting of diffeomorphisms (satisfying certain conditions) of the absolutes of Bruhat-Tits trees; they can be regarded as precisely the diffeomorphism groups of Cantor perfect sets. Several series of unitary representations of these groups are constructed, including the analogs of highest-weight representations.

  1. Quadrature formulas on the unit circle with prescribed nodes and maximal domain of validity

    NASA Astrophysics Data System (ADS)

    Bultheel, Adhemar; Daruis, Leyla; González-Vera, Pablo

    2009-09-01

    In this paper we investigate the Szego-Radau and Szego-Lobatto quadrature formulas on the unit circle. These are (n+m)-point formulas for which m nodes are fixed in advance, with m=1 and m=2 respectively, and which have a maximal domain of validity in the space of Laurent polynomials. This means that the free parameters (free nodes and positive weights) are chosen such that the quadrature formula is exact for all powers zj, -p<=j<=p, with p=p(n,m) as large as possible.

  2. [Ars medica Anhaltina (V): Physicians and scientists of the Anhalt territories in Goethe's circle of friends].

    PubMed

    Kaiser, W; Völker, A

    1986-11-15

    From the view of regional history for the Anhaltine territory several medical and natural scientists are to be mentioned whom a remarkable role can be ascribed in the Weimarian circle round Goethe. The Bernburg physician and pharmaceutist Bucholz became there for many years his consultee for questions of natural sciences; Gren, who also came from Bernburg, became the antipode in the dispute about problems of optics. Goethe visited Gilbert, who was educated in Dessau, in his laboratory in Halle. In old age the poet was supported as physician and friend by Carl Vogel, born in Dessau, who described Goethe's last disease.

  3. The Low-Metallicity Galaxy, I Zw 18 (Z=1/50 Z(circle dot))

    NASA Technical Reports Server (NTRS)

    Heap, Sara R.

    2003-01-01

    Both observations and evolutionary models indicate that rotation becomes a more important factor at lower metallicities. Some important effects of rotation include: increasing the rate of mass-loss; lowering the effective gravity; altering the evolutionary track on the Hertzsprung-Russell Diagram (HRD); extending the main-sequence phase (both on the HR diagram and in time); and mixing of CNO-processed elements up to the stellar surface. We discuss these effects for massive stars in the low-metallicity galaxy, I Zw 18 (Z=1/50 Z(circle dot)) and their implications for the first stars.

  4. NanoCluster Beacons as reporter probes in rolling circle enhanced enzyme activity detection

    NASA Astrophysics Data System (ADS)

    Juul, Sissel; Obliosca, Judy M.; Liu, Cong; Liu, Yen-Liang; Chen, Yu-An; Imphean, Darren M.; Knudsen, Birgitta R.; Ho, Yi-Ping; Leong, Kam W.; Yeh, Hsin-Chih

    2015-04-01

    As a newly developed assay for the detection of endogenous enzyme activity at the single-catalytic-event level, Rolling Circle Enhanced Enzyme Activity Detection (REEAD) has been used to measure enzyme activity in both single human cells and malaria-causing parasites, Plasmodium sp. Current REEAD assays rely on organic dye-tagged linear DNA probes to report the rolling circle amplification products (RCPs), the cost of which may hinder the widespread use of REEAD. Here we show that a new class of activatable probes, NanoCluster Beacons (NCBs), can simplify the REEAD assays. Easily prepared without any need for purification and capable of large fluorescence enhancement upon hybridization, NCBs are cost-effective and sensitive. Compared to conventional fluorescent probes, NCBs are also more photostable. As demonstrated in reporting the human topoisomerases I (hTopI) cleavage-ligation reaction, the proposed NCBs suggest a read-out format attractive for future REEAD-based diagnostics.As a newly developed assay for the detection of endogenous enzyme activity at the single-catalytic-event level, Rolling Circle Enhanced Enzyme Activity Detection (REEAD) has been used to measure enzyme activity in both single human cells and malaria-causing parasites, Plasmodium sp. Current REEAD assays rely on organic dye-tagged linear DNA probes to report the rolling circle amplification products (RCPs), the cost of which may hinder the widespread use of REEAD. Here we show that a new class of activatable probes, NanoCluster Beacons (NCBs), can simplify the REEAD assays. Easily prepared without any need for purification and capable of large fluorescence enhancement upon hybridization, NCBs are cost-effective and sensitive. Compared to conventional fluorescent probes, NCBs are also more photostable. As demonstrated in reporting the human topoisomerases I (hTopI) cleavage-ligation reaction, the proposed NCBs suggest a read-out format attractive for future REEAD-based diagnostics. Electronic

  5. The Heidelberg circle: German inflections on the professionalization of Russian chemistry in the 1860s.

    PubMed

    Gordin, Michael D

    2008-01-01

    The success of the "second importation" of science to Russia during the Great Reforms of the 1860s is illustrated by examining the extended postdoctoral study of chemists in Heidelberg. While there, they adapted the Russian intelligentsia institution of the "circle," or kruzhok, to cope with their alienation from the German culture they were confronting. Upon their return to Russia, they felt the lack of the communicative network they had established while abroad and reimported the kruzhok to serve as a central model for the formation of the Russian Chemical Society in 1868.

  6. Bathymetric and Hydraulic Survey of the Matanuska River near Circle View Estates, Alaska

    USGS Publications Warehouse

    Conaway, Jeffrey S.

    2008-01-01

    An acoustic Doppler current profiler interfaced with a differentially corrected global positioning system was used to map bathymetry and multi-dimensional velocities on the Matanuska River near Circle View Estates, Alaska. Data were collected along four spur dikes and a bend in the river during a period of active bank erosion. These data were collected as part of a larger investigation into channel processes being conducted to aid land managers with development of a long-term management plan for land near the river. The banks and streambed are composed of readily erodible material and the braided channels frequently scour and migrate. Lateral channel migration has resulted in the periodic loss of properties and structures along the river for decades. For most of the survey, discharge of the Matanuska River was less than the 25th percentile of long-term streamflow. Despite this relatively low flow, measured water velocities were as high as 15 feet per second. The survey required a unique deployment of the acoustic Doppler current profiler in a tethered boat that was towed by a small inflatable raft. Data were collected along cross sections and longitudinal profiles. The bathymetric and velocity data document river conditions before the installation of an additional spur dike in 2006 and during a period of bank erosion. Data were collected along 1,700 feet of river in front of the spur dikes and along 1,500 feet of an eroding bank. Data collected at the nose of spur dikes 2, 3, and 4 were selected to quantify the flow hydraulics at the locations subject to the highest velocities. The measured velocities and flow depths were greatest at the nose of the downstream-most spur dike. The maximum point velocity at the spur dike nose was 13.3 feet per second and the maximum depth-averaged velocity was 11.6 feet per second. The maximum measured depth was 12.0 feet at the nose of spur dike 4 and velocities greater than 10 feet per second were measured to a depth of 10 feet

  7. Replication of avocado sunblotch viroid: evidence for a symmetric pathway with two rolling circles and hammerhead ribozyme processing.

    PubMed Central

    Daròs, J A; Marcos, J F; Hernández, C; Flores, R

    1994-01-01

    The structure of a series of RNAs extracted from avocado infected by the 247-nt avocado sunblotch viroid (ASBVd) was investigated. The identification of multistranded complexes containing circular ASBVd RNAs of (+) and (-) polarity suggests that replication of ASBVd proceeds through a symmetric pathway with two rolling circles where these two circular RNAs are the templates. This is in contrast to the replication of potato spindle tuber viroid and probably of most of its related viroids, which proceeds via an asymmetric pathway where circular (+)-strand and linear multimeric (-)-strand RNAs are the two templates. Linear (+) and (-) ASBVd RNAs of subgenomic length (137 nt and about 148 nt, respectively) and one linear (+)-strand ASBVd RNA of supragenomic length (383-384 nt) were also found in viroid-infected tissue. The two linear (+)-strand RNAs have the same 5'- and 3'-terminal sequences, with the supragenomic species being a fusion product of the monomeric and subgenomic (+)-strand ASBVd RNAs. The 3' termini of these two (+)-strand molecules, which at least in the subgenomic RNA has an extra nontemplate cytidylate residue, could represent sites of either premature termination of the (+)-strands or specific initiation of the (-)-strands. The 5' termini of sub- and supragenomic (+)-strand and the 5' terminus of the subgenomic (-)-strand ASBVd RNA are identical to those produced in the in vitro self-cleavage reactions of (+) and (-) dimeric ASBVd RNAs, respectively. These observations strongly suggest that the hammerhead structures which mediate the in vitro self-cleavage reactions are also operative in vivo. Images Fig. 1 Fig. 3 Fig. 4 Fig. 5 PMID:7809126

  8. Revisiting the vicious circle of dry eye disease: a focus on the pathophysiology of meibomian gland dysfunction

    PubMed Central

    Baudouin, Christophe; Messmer, Elisabeth M; Geerling, Gerd; Akova, Yonca A; Benítez-del-Castillo, José; Boboridis, Kostas G; Merayo-Lloves, Jesús; Rolando, Maurizio; Labetoulle, Marc

    2016-01-01

    Meibomian gland dysfunction (MGD) is the most frequent cause of dry eye disease (DED). Eyelid inflammation, microbial growth, associated skin disorders as well as potentially severe corneal complications culminate to make MGD a complex multifactorial disorder. It is probable that MGD is a heterogeneous condition arising from any combination of the following five separate pathophysiological mechanisms: eyelid inflammation, conjunctival inflammation, corneal damage, microbiological changes and DED resulting from tear film instability. The pathogenesis of both MGD and DED can be described in terms of a ‘vicious circle’: the underlying pathophysiological mechanisms of DED and MGD interact, resulting in a double vicious circle. The MGD vicious circle is self-stimulated by microbiological changes, which results in increased melting temperature of meibum and subsequent meibomian gland blockage, reinforcing the vicious circle of MGD. Meibomian gland blockage, dropout and inflammation directly link the two vicious circles. MGD-associated tear film instability provides an entry point into the vicious circle of DED and leads to hyperosmolarity and inflammation, which are both a cause and consequence of DED. Here we propose a new pathophysiological scheme for MGD in order to better identify the pathological mechanisms involved and to allow more efficient targeting of therapeutics. Through better understanding of this scheme, MGD may gain true disease status rather than being viewed as a mere dysfunction. PMID:26781133

  9. [Geostatistics analyzing to cause of formation of circle distribution of plant communities in Horqin Sandy Land].

    PubMed

    He, Xingdong; Gao, Yubao; Zhao, Wenzhi; Cong, Zili

    2004-09-01

    Investigation results in the present study showed that plant communities took typical concentric circles distribution patterns along habitat gradient from top, slope to interdune on a few large fixed dunes in middle part of Korqin Sandy Land. In order to explain this phenomenon, analysis of water content and its spatial heterogeneity in sand layers on different locations of dunes was conducted. In these dunes, water contents in sand layers of the tops were lower than those of the slopes; both of them were lower than those of the interdunes. According to the results of geostatistics analysis, whether shifting dune or fixed dune, spatial heterogeneity of water contents in sand layers took on regular changes, such as ratios between nugget and sill and ranges reduced gradually, fractal dimension increased gradually, the regular changes of these parameters indicated that random spatial heterogeneity reduced gradually, and autocorrelation spatial heterogeneity increased gradually from the top, the slope to the interdune. The regular changes of water contents in sand layers and their spatial heterogeneity of different locations of the dunes, thus, might be an important cause resulted in the formation of the concentric circles patterns of the plant communities on these fixed dunes.

  10. Enhancing Students' Conceptual Understanding by Engaging Science Text with Reflective Writing as a Hermeneutical Circle

    NASA Astrophysics Data System (ADS)

    Kalman, Calvin S.

    2011-02-01

    Students can have great difficulty reading scientific texts and trying to cope with the professor in the classroom. Part of the reason for students' difficulties is that for a student taking a science gateway course the language, ontology and epistemology of science are akin to a foreign culture. There is thus an analogy between such a student and an anthropologist spending time among a native group in some remote part of the globe. This brings us naturally to the subject of hermeneutics. It is through language that we attempt to understand an alien culture. The hermeneutical circle involves the interplay between our construct of the unfamiliar with our own outlook that deepens with each pass. It can be argued that for novice students to acquire a full understanding of scientific texts, they also need to pursue a recurrent construction of their comprehension of scientific concepts. In this paper it is shown how an activity, reflective-writing, can enhance students' understanding of concepts in their textbook by getting students to approach text in the manner of a hermeneutical circle. This is illustrated using studies made at three post-secondary institutions.

  11. Niche-partitioning of edaphic microbial communities in the Namib Desert gravel plain Fairy Circles.

    PubMed

    Ramond, Jean-Baptiste; Pienaar, Annelize; Armstrong, Alacia; Seely, Mary; Cowan, Don A

    2014-01-01

    Endemic to the Namib Desert, Fairy Circles (FCs) are vegetation-free circular patterns surrounded and delineated by grass species. Since first reported the 1970's, many theories have been proposed to explain their appearance, but none provide a fully satisfactory explanation of their origin(s) and/or causative agent(s). In this study, we have evaluated an early hypothesis stating that edaphic microorganisms could be involved in their formation and/or maintenance. Surface soils (0-5 cm) from three different zones (FC center, FC margin and external, grass-covered soils) of five independent FCs were collected in April 2013 in the Namib Desert gravel plains. T-RFLP fingerprinting of the bacterial (16S rRNA gene) and fungal (ITS region) communities, in parallel with two-way crossed ANOSIM, showed that FC communities were significantly different to those of external control vegetated soil and that each FC was also characterized by significantly different communities. Intra-FC communities (margin and centre) presented higher variability than the controls. Together, these results provide clear evidence that edaphic microorganisms are involved in the Namib Desert FC phenomenon. However, we are, as yet, unable to confirm whether bacteria and/or fungi communities are responsible for the appearance and development of FCs or are a general consequence of the presence of the grass-free circles.

  12. Self-organized vortices of circling self-propelled particles and curved active flagella

    NASA Astrophysics Data System (ADS)

    Yang, Yingzi; Qiu, Feng; Gompper, Gerhard

    2014-01-01

    Self-propelled pointlike particles move along circular trajectories when their translocation velocity is constant and the angular velocity related to their orientation vector is also constant. We investigate the collective behavior of ensembles of such circle swimmers by Brownian dynamics simulations. If the particles interact via a "velocity-trajectory coordination" rule within neighboring particles, a self-organized vortex pattern emerges. This vortex pattern is characterized by its particle-density correlation function Gρ, the density correlation function Gc of trajectory centers, and an order parameter S representing the degree of the aggregation of the particles. Here we systematically vary the system parameters, such as the particle density and the interaction range, in order to reveal the transition of the system from a light-vortex-dominated to heavy-vortex-dominated state, where vortices contain mainly a single and many self-propelled particles, respectively. We also study a semidilute solution of curved, sinusoidal-beating flagella, as an example of circling self-propelled particles with explicit propulsion mechanism and excluded-volume interactions. Our simulation results are compared with previous experimental results for the vortices in sea-urchin sperm solutions near a wall. The properties of the vortices in simulations and experiments are found to agree quantitatively.

  13. Linking Science Analysis with Observation Planning: A Full Circle Data Lifecycle

    NASA Technical Reports Server (NTRS)

    Grosvenor, Sandy; Jones, Jeremy; Koratkar, Anuradha; Li, Connie; Mackey, Jennifer; Neher, Ken; Wolf, Karl; Obenschain, Arthur F. (Technical Monitor)

    2001-01-01

    A clear goal of the Virtual Observatory (VO) is to enable new science through analysis of integrated astronomical archives. An additional and powerful possibility of the VO is to link and integrate these new analyses with planning of new observations. By providing tools that can be used for observation planning in the VO, the VO will allow the data lifecycle to come full circle: from theory to observations to data and back around to new theories and new observations. The Scientist's Expert Assistant (SEA) Simulation Facility (SSF) is working to combine the ability to access existing archives with the ability to model and visualize new observations. Integrating the two will allow astronomers to better use the integrated archives of the VO to plan and predict the success of potential new observations more efficiently, The full circle lifecycle enabled by SEA can allow astronomers to make substantial leaps in the quality of data and science returns on new observations. Our paper examines the exciting potential of integrating archival analysis with new observation planning, such as performing data calibration analysis on archival images and using that analysis to predict the success of new observations, or performing dynamic signal-to-noise analysis combining historical results with modeling of new instruments or targets. We will also describe how the development of the SSF is progressing and what have been its successes and challenges.

  14. A model for leaf initiation: determination of phyllotaxis by waves in the generative circle.

    PubMed

    Abraham-Shrauner, Barbara; Pickard, Barbara G

    2011-11-01

    A biophysical model is proposed for how leaf primordia are positioned on the shoot apical: meristem in both spiral and whorl phyllotaxes. Primordia are initiated by signals that propagate: in the epidermis in both azimuthal directions away from the cotyledons or the most recently: specified primordia. The signals are linear waves as inferred from the spatial periodicity of the: divergence angle and a temporal periodicity. The periods of the waves, which represent actively: transported auxin, are much smaller than the plastochron interval. Where oppositely directed: waves meet at one or more angular positions on the periphery of the generative circle, auxin: concentration builds and as in most models this stimulates local movement of auxin to: underlying cells, where it promotes polarized cell division and expansion. For higher order: spirals the wave model requires asymmetric function of auxin transport; that is, opposite wave: speeds differ. An algorithm for determination of the angular positions of leaves in common leaf: phyllotaxic configurations is proposed. The number of turns in a pattern repeat, number of leaves: per level and per pattern repeat, and divergence angle are related to speed of auxin transport and: radius of the generative circle. The rule for composition of Fibonacci or Lucas numbers: associated with some phyllotaxes is discussed. A subcellular model suggests how the shoot: meristem might specify either symmetric or asymmetric transport of auxin away from the: forming primordia that produce it. Biological tests that could make or break the mathematical: and molecular hypotheses are proposed.

  15. A CLIQUE algorithm using DNA computing techniques based on closed-circle DNA sequences.

    PubMed

    Zhang, Hongyan; Liu, Xiyu

    2011-07-01

    DNA computing has been applied in broad fields such as graph theory, finite state problems, and combinatorial problem. DNA computing approaches are more suitable used to solve many combinatorial problems because of the vast parallelism and high-density storage. The CLIQUE algorithm is one of the gird-based clustering techniques for spatial data. It is the combinatorial problem of the density cells. Therefore we utilize DNA computing using the closed-circle DNA sequences to execute the CLIQUE algorithm for the two-dimensional data. In our study, the process of clustering becomes a parallel bio-chemical reaction and the DNA sequences representing the marked cells can be combined to form a closed-circle DNA sequences. This strategy is a new application of DNA computing. Although the strategy is only for the two-dimensional data, it provides a new idea to consider the grids to be vertexes in a graph and transform the search problem into a combinatorial problem.

  16. Cervical carotid and circle of willis arterial anatomy of macaque monkeys: a comparative anatomy study.

    PubMed

    Kumar, Nishant; Lee, John J; Perlmutter, Joel S; Derdeyn, Colin P

    2009-07-01

    Macaque monkeys are used in many research applications, including cerebrovascular investigations. However, detailed catalogs of the relevant vascular anatomy are scarce. We present our experience with macaque vessel patterns as determined by digital subtraction angiography of 34 different monkeys. We retrospectively analyzed digital subtraction angiograms obtained during experimental internal carotid artery (ICA) catheterization and subsequent injection of 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine. Results were catalogued according to vascular distribution and variants observed. Macaque monkeys have a bovine aortic arch. The carotid vessels generally bifurcate, but are occasionally observed to divide into three vessels. The external carotid gives rise primarily to two trunks: an occipital branch and a common vessel that subsequently gives off the lingual, facial, and superior thyroid arteries. The internal maxillary artery may be present as a terminal branch of the external carotid or as a branch of the occipital artery. The ICA is similar in course to that of the human. The anterior circle of Willis was intact in all monkeys in our study. Its primary difference from that of the human is the union of the bilateral anterior cerebral arteries as a single (azygous) median vessel. Macaque cervical carotid and circle of Willis arterial anatomy differs from humans in a couple of specific patterns. Knowledge of these differences and similarities between human and macaque anatomy is important in developing endovascular macaque models of human diseases, such as ischemic stroke.

  17. Infraorbital Dark Circles: A Review of the Pathogenesis, Evaluation and Treatment

    PubMed Central

    Vrcek, Ivan; Ozgur, Omar; Nakra, Tanuj

    2016-01-01

    Infraorbital dark circles represent a common and multifactorial challenge in the world of aesthetic medicine and are the result of a variety of factors including deep facial anatomy, soft tissue changes, as well as contributions from the skin. A variety of treatment options exist, and a customised management strategy can be developed for the particular anatomic changes present. A literature search using MEDLINE and non-MEDLINE sources was performed utilising keywords including: ‘Dark circles’ ‘infraorbital dark circles’, ‘infraorbital pigment’, ‘under-eye circles’ and ‘lower eyelid bags’. A comprehensive review of the literature was performed and the data were assimilated with evidence from our practice. This review provides a detailed discussion of the aetiology, pathogenesis, evaluation and management of infraorbital dark circles. An understanding of the deep and superficial anatomy is crucial to the management of this complex entity. The armamentarium for treatment includes minimally invasive interventions such as makeup and cosmeceuticals, a variety of laser and chemical treatments, fillers and fat transfer, as well as more invasive surgical manoeuvres. PMID:27398005

  18. Walt Disney World`s utility efficiency awards and environmental circles of excellence

    SciTech Connect

    Allen, P.J.; Kivler, W.B.

    1996-05-01

    This paper describes an innovative approach to energy conservation that has been started at WALT DISNEY WORLD. The program that was established was designed to heighten the awareness of energy usage in our Management and Cast Members, establish a method for recognizing and rewarding positive energy conservation efforts and, most importantly, keeping the effort simple and fun. Two programs work together to meet this goal: Utility Efficiency Awards and the Environmental Circles of Excellence. The Utility Efficiency Awards are given to the top areas that have demonstrated a reduction in utility consumption relative to the same period in prior years. More importantly, a report is generated that shows a best-to-worst ranking. Relying on the idea that {open_quotes}nobody wants to be on the bottom of the list{close_quotes}, conservation is enhanced by focusing attention on improving efficiency. To encourage direct cast member involvement in our environmental program, the Environmental Circles of Excellence were created. These groups, made up of hourly and salaried cast members, discuss their location`s environmental commitments, set goals and implement programs. This paper describes these initiatives in detail and presents some initial results that have heightened the awareness of energy conservation at WALT DISNEY WORLD.

  19. Vervet monkeys solve a multiplayer "forbidden circle game" by queuing to learn restraint.

    PubMed

    Fruteau, Cécile; van Damme, Eric; Noë, Ronald

    2013-04-22

    In social dilemmas, the ability of individuals to coordinate their actions is crucial to reach group optima. Unless exacted by power or force, coordination in humans relies on a common understanding of the problem, which is greatly facilitated by communication. The lack of means of consultation about the nature of the problem and how to solve it may explain why multiagent coordination in nonhuman vertebrates has commonly been observed only when multiple individuals react instantaneously to a single stimulus, either natural or experimentally simulated, for example a predator, a prey, or a neighboring group. Here we report how vervet monkeys solved an experimentally induced coordination problem. In each of three groups, we trained a low-ranking female, the "provider," to open a container holding a large amount of food, which the providers only opened when all individuals dominant to them ("dominants") stayed outside an imaginary "forbidden circle" around it. Without any human guidance, the dominants learned restraint one by one, in hierarchical order from high to low. Once all dominants showed restraint immediately at the start of the trial, the providers opened the container almost instantly, saving all individuals opportunity costs due to lost foraging time. Solving this game required trial-and-error learning based on individual feedback from the provider to each dominant, and all dominants being patient enough to wait outside the circle while others learned restraint. Communication, social learning, and policing by high-ranking animals played no perceptible role.

  20. Problems of optimal transportation on the circle and their mechanical applications

    NASA Astrophysics Data System (ADS)

    Plakhov, Alexander; Tchemisova, Tatiana

    2017-02-01

    We consider a mechanical problem concerning a 2D axisymmetric body moving forward on the plane and making slow turns of fixed magnitude about its axis of symmetry. The body moves through a medium of non-interacting particles at rest, and collisions of particles with the body's boundary are perfectly elastic (billiard-like). The body has a blunt nose: a line segment orthogonal to the symmetry axis. It is required to make small cavities with special shape on the nose so as to minimize its aerodynamic resistance. This problem of optimizing the shape of the cavities amounts to a special case of the optimal mass transportation problem on the circle with the transportation cost being the squared Euclidean distance. We find the explicit solution for this problem when the amplitude of rotation is smaller than a fixed critical value, and give a numerical solution otherwise. As a by-product, we get explicit description of the solution for a class of optimal transportation problems on the circle.

  1. Spindle error motion measurement using concentric circle grating and sinusoidal frequency-modulated semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Higuchi, Masato; Vu, Thanh-Tung; Aketagawa, Masato

    2016-11-01

    The conventional method of measuring the radial, axial and angular spindle motion is complicated and needs large spaces. Smaller instrument is better in terms of accurate and practical measurement. A method of measuring spindle error motion using a sinusoidal phase modulation and a concentric circle grating was described in the past. In the method, the concentric circle grating with fine pitch is attached to the spindle. Three optical sensors are fixed under grating and observe appropriate position of grating. The each optical sensor consists of a sinusoidal frequency modulated semiconductor laser as the light source, and two interferometers. One interferometer measures an axial spindle motion by detecting the interference fringe between reflected beam from fixed mirror and 0th-order diffracted beam. Another interferometer measures a radial spindle motion by detecting the interference fringe between ±2nd-order diffracted beams. With these optical sensor, 3 axial and 3 radial displacement of grating can be measured. From these measured displacements, axial, radial and angular spindle motion is calculated concurrently. In the previous experiment, concurrent measurement of the one axial and one radial spindle displacement at 4rpm was described. In this paper, the sinusoidal frequency modulation realized by modulating injection current is used instead of the sinusoidal phase modulation, which contributes simplicity of the instrument. Furthermore, concurrent measurement of the 5 axis (1 axial, 2 radial and 2 angular displacements) spindle motion at 4000rpm may be described.

  2. Child protection network and the intersector implementation of the circle of security as alternatives to medication☆

    PubMed Central

    Becker, Ana Laura Martins M.M.; de Souza, Paulo Haddad; de Oliveira, Mônica Martins; Paraguay, Nestor Luiz Bruzzi B.

    2014-01-01

    Objectives: To describe the clinical history of a child with aggressive behavior and recurring death-theme speech, and report the experience of the team of authors, who proposed an alternative to medication through the establishment of a protection network and the inter-sector implementation of the circle of security concept. Case description: A 5-year-old child has a violent and aggressive behavior at the daycare. The child was diagnosed by the healthcare center with depressive disorder and behavioral disorder, and was medicated with sertraline and risperidone. Side effects were observed, and the medications were discontinued. Despite several actions, such as talks, teamwork, psychological and psychiatric follow-up, the child's behavior remained unchanged. Remarks: A unique therapeutic project was developed by Universidade Estadual de Campinas' Medical School students in order to establish a connection between the entities responsible for the child's care (daycare center, healthcare center, and family). Thus, the team was able to develop a basic care protection network. The implementation of the inter-sector circle of security, as well as the communication and cooperation among the teams, produced very favorable results in this case. This initiative was shown to be a feasible and effective alternative to the use of medication for this child. PMID:25479857

  3. The Boston-area HASWIC Research Circle: an innovative participatory method for coloring in the picture of a special work environment.

    PubMed

    Moir, Susan; Azaroff, Lenore S

    2007-01-01

    Recent qualitative studies have investigated some of the hazards affecting women in non-traditional trades such as construction. However, one-time interactions among researcher participants, and between researchers and participants, in standard settings such as focus groups and interviews, cannot provide the time, space, and relationships to fully explore tradeswomen's in-depth knowledge of their work environment. This study applied a Scandinavian method called the Research Circle to convene a group of experienced women construction workers repeatedly over a period of two years so they could collaborate with researchers in explaining workplace issues. The results both validated and expanded upon previous findings about health and safety for women in construction, including gender discrimination, lack of access to sanitary facilities, retaliation for reporting hazards and injuries, and inadequate training and equipment. Especially important, findings illustrate some of the complex hierarchical social structures involved in both female and male construction workers responding to hazardous conditions.

  4. Are we indeed what we eat? Street food consumption in the Market Circle area of Takoradi, Ghana.

    PubMed

    Hiamey, Stephen Edem; Amuquandoh, Francis Eric; Boison, Grace Aba

    2013-01-01

    The paper examines street foods consumption in the Market Circle of Sekondi-Takoradi, Ghana. The data used for the study were obtained from individuals who were either purchasing or consuming street foods in the Market Circle in August of 2011. The results revealed that the average consumer makes use of street foods six times in a week and there was a penchant for carbohydrate based foods over other types of street foods. Reasons including cost saving, convenience and eating on credit were noted to underlie the consumption of street foods in the area. Based on the findings, it was concluded that the high consumption of street foods in the Market Circle was for reasons other than nutrition and health.

  5. Generic Equations for Constructing Smooth Paths Along Circles and Tangent Lines With Application to Airport Ground Paths

    NASA Technical Reports Server (NTRS)

    Barker, L. Keith

    1998-01-01

    The primary purpose of this publication is to develop a mathematical model to describe smooth paths along any combination of circles and tangent lines. Two consecutive circles in a path are either tangent (externally or internally) or they appear on the same (lateral) or opposite (transverse) sides of a connecting tangent line. A path may start or end on either a segment or circle. The approach is to use mathematics common to robotics to design the path as a multilink manipulator. This approach allows a hierarchical view of the problem and keeps the notation manageable. A user simply specifies a few parameters to configure a path. Necessary and sufficient conditions automatically ensure the consistency of the inputs for a smooth path. Two example runway exit paths are given, and an angle to go assists in knowing when to switch from one path element to the next.

  6. Stereotypic circling behavior in mice with vestibular dysfunction: asymmetrical effects of intrastriatal microinjection of a dopamine agonist.

    PubMed

    Ishiguro, Akio; Inagaki, Masumi; Kaga, Makiko

    2007-07-01

    Bronx Waltzer (bv) mouse, which has been used as a model of hearing and vestibular dysfunction, shows remarkable repetitive circling behavior. This study investigated whether the behavior is caused by the asymmetry of striatal function by observing the behavior of the bv mice following microinjection of dopamine D1 agonist, A68930 into the striatum ipsilaterally and contralaterally to the preferred direction of rotation separately. High dose of the drug induced opposite effects on ipsilateral rotations by the side of injections with statistical significance (p = .0026). These results suggested that the stereotypic circling behavior involves striatum and is based on striatal asymmetry.

  7. On-chip detection of rolling circle amplified DNA molecules from Bacillus globigii spores and Vibrio cholerae.

    PubMed

    Østerberg, Frederik W; Rizzi, Giovanni; Donolato, Marco; Bejhed, Rebecca S; Mezger, Anja; Strömberg, Mattias; Nilsson, Mats; Strømme, Maria; Svedlindh, Peter; Hansen, Mikkel F

    2014-07-23

    For the first time DNA coils formed by rolling circle amplification are quantified on-chip by Brownian relaxation measurements on magnetic nanobeads using a magnetoresistive sensor. No external magnetic fields are required besides the magnetic field arising from the current through the sensor, which makes the setup very compact. Limits of detection down to 500 Bacillus globigii spores and 2 pM of Vibrio cholerae are demonstrated, which are on the same order of magnitude or lower than those achieved previously using a commercial macro-scale AC susceptometer. The chip-based readout is an important step towards the realization of field tests based on rolling circle amplification molecular analyses.

  8. Unique Microbial Phylotypes in Namib Desert Dune and Gravel Plain Fairy Circle Soils

    PubMed Central

    van der Walt,, Andries J.; Johnson, Riegardt M.; Cowan, Don A.; Seely, Mary

    2016-01-01

    ABSTRACT Fairy circles (FCs) are barren circular patches of soil surrounded by grass species. Their origin is poorly understood. FCs feature in both the gravel plains and the dune fields of the Namib Desert. While a substantial number of hypotheses to explain the origin and/or maintenance of fairy circles have been presented, none are completely consistent with either their properties or their distribution. In this study, we investigated the hypothesis that FC formation in dunes and gravel plains is due to microbial phytopathogenesis. Surface soils from five gravel plain and five dune FCs, together with control soil samples, were analyzed using high-throughput sequencing of bacterial/archaeal (16S rRNA gene) and fungal (internal transcribed spacer [ITS] region) phylogenetic markers. Our analyses showed that gravel plain and dune FC microbial communities are phylogenetically distinct and that FC communities differ from those of adjacent vegetated soils. Furthermore, various soil physicochemical properties, particularly the pH, the Ca, P, Na, and SO4 contents, the soil particle size, and the percentage of carbon, significantly influenced the compositions of dune and gravel plain FC microbial communities, but none were found to segregate FC and vegetated soil communities. Nevertheless, 9 bacterial, 1 archaeal, and 57 fungal phylotypes were identified as FC specific, since they were present within the gravel plain and dune FC soils only, not in the vegetated soils. Some of these FC-specific phylotypes were assigned to taxa known to harbor phytopathogenic microorganisms. This suggests that these FC-specific microbial taxa may be involved in the formation and/or maintenance of Namib Desert FCs. IMPORTANCE Fairy circles (FCs) are mysterious barren circular patches of soil found within a grass matrix in the dune fields and gravel plains of the Namib Desert. Various hypotheses attempting to explain this phenomenon have been proposed. To date, however, none have been

  9. Automatic diagnosis of malaria based on complete circle-ellipse fitting search algorithm.

    PubMed

    Sheikhhosseini, M; Rabbani, H; Zekri, M; Talebi, A

    2013-12-01

    Diagnosis of malaria parasitemia from blood smears is a subjective and time-consuming task for pathologists. The automatic diagnostic process will reduce the diagnostic time. Also, it can be worked as a second opinion for pathologists and may be useful in malaria screening. This study presents an automatic method for malaria diagnosis from thin blood smears. According to this fact that malaria life cycle is started by forming a ring around the parasite nucleus, the proposed approach is mainly based on curve fitting to detect parasite ring in the blood smear. The method is composed of six main phases: stain object extraction step, which extracts candidate objects that may be infected by malaria parasites. This phase includes stained pixel extraction step based on intensity and colour, and stained object segmentation by defining stained circle matching. Second step is preprocessing phase which makes use of nonlinear diffusion filtering. The process continues with detection of parasite nucleus from resulted image of previous step according to image intensity. Fourth step introduces a complete search process in which the circle search step identifies the direction and initial points for direct least-square ellipse fitting algorithm. Furthermore in the ellipse searching process, although parasite shape is completed undesired regions with high error value are removed and ellipse parameters are modified. Features are extracted from the parasite candidate region instead of whole candidate object in the fifth step. By employing this special feature extraction way, which is provided by special searching process, the necessity of employing clump splitting methods is removed. Also, defining stained circle matching process in the first step speeds up the whole procedure. Finally, a series of decision rules are applied on the extracted features to decide on the positivity or negativity of malaria parasite presence. The algorithm is applied on 26 digital images which are provided

  10. Circumplex Scales of Intergroup Goals: an interpersonal circle model of goals for interactions between groups.

    PubMed

    Locke, Kenneth D

    2014-04-01

    Six studies (N = 1,682) used the Circumplex Scales of Intergroup Goals (CSIG)--an inventory based on the interpersonal circle-to assess individuals' agentic and communal goals for interactions between groups (nations in Studies 1-4, organizations in Study 5, political parties in Study 6). Noteworthy findings included the following: People with stronger unagentic-and-uncommunal goals perceived other groups as dangers, were wary of intergroup negotiations, and sanctioned authoritarianism and inequality. People with stronger agentic-and-uncommunal goals proudly identified with their country and compatriots, disapproved of nations unlike their own, and preferred the conservative candidate in a national election. People with stronger communal-and-unagentic goals identified with people beyond their ingroup, and wanted their group to resolve intergroup conflicts by behaving cooperatively rather than competitively or aggressively. By providing an encompassing framework capable of organizing and integrating these types of diverse findings, the circumplex model can facilitate cumulative scientific progress.

  11. Full-Circle Color Panorama of Phoenix Landing Site on Northern Mars, Vertical Projection

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This view combines more than 400 images taken during the first several weeks after NASA's Phoenix Mars Lander arrived on an arctic plain at 68.22 degrees north latitude, 234.25 degrees east longitude on Mars.

    The full-circle panorama in approximately true color shows the polygonal patterning of ground in the landing area, similar to patterns in permafrost areas on Earth. North is toward the top. Trenches where Phoenix's robotic arm has been exposing subsurface material are visible just north of the lander.

    This view comprises more than 100 different camera pointings, with images taken through three different filters at each pointing. It is presented here as a vertical projection.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  12. Circle quorum system-based non-stop network service model.

    PubMed

    Song, Ping; Sun, Jian-ling; He, Zhi-jun

    2004-05-01

    Rapid developments in network systems of business service have resulted in more reliance on distributed computing, typified by "subscriber/push" architectures. Unfortunately, frequent and unexpectable network failures were routine, and downtime was not in hours, but in days. High availability has become the most important factor decreasing business risk and improving Quality of Service. Cluster technology has solved the non-stop problem on Local Area Network. However, most technologies including cluster today fail to ensure the non-stop Internet service based on Routers. With good performance on high availability and fault tolerance, quorum systems are very suitable for application to distributed business service networks. In this work, we modeled and developed a non-stop Internet service system based on a new quorum system, circle quorum system, for Boston Mutual Fund Broker, US. With five protocols, it provided highly available data services for clients on Internet.

  13. Quality control circles: will they work at Sandia. Findings from a review of 66 sources

    SciTech Connect

    Jeys, G.H.

    1982-01-01

    Quality Control Circles (QCC's) meet regularly to solve limited, but important, problems related directly to their work. The QCC is organized so that the worker becomes involved in problem solving and quality awareness in meaningful and creative ways. Participation is voluntary. This concept has been successfully used in Japan for two decades. QCC's are now being implemented at an accelerating rate world-wide. There are questions as to QCC's applicability in the United States and in particular with respect to an R and D facility such as Sandia. This paper summarizes information about the QCC concept with respect to its implementation and applicability to Sandia. Information was extracted from 66 sources as noted in an Annotated Bibliography. Analysis techniques used by QCC's were utilized in the construction of this paper, especially with the Annotated Bibliography.

  14. Applying the Advancing Excellence in America's Nursing Homes Circle of Success to improving and sustaining quality.

    PubMed

    Bakerjian, Debra; Zisberg, Anna

    2013-01-01

    Looking forward to the Quality Assurance Performance Improvement (QAPI) program to be implemented and required in 2014, and as nursing home staff provide care for residents with increasingly complex health issues, knowledge of how to implement quality improvement (QI) is imperative. The nursing home administrator and director of nursing (DON) provide overall leadership, but it is the primary responsibility of the DON and other registered nurse staff to implement and manage the day to day QI process. This article describes potential roles of nursing leaders and key components of a QI project using a pressure ulcer case study exemplar to illustrate a quality improvement process. The authors suggest specific methods that RN leaders can employ using the Advancing Excellence Campaign Circle of Success as an organizing framework along with evidence-based resources. Nursing home leaders could use this article as a guideline for implementing any clinical quality improvement process.

  15. Ultrasensitive detection of microRNA through rolling circle amplification on a DNA tetrahedron decorated electrode.

    PubMed

    Miao, Peng; Wang, Bidou; Meng, Fanyu; Yin, Jian; Tang, Yuguo

    2015-03-18

    MicroRNAs are a class of evolutionally conserved, small noncoding RNAs involved in the regulation of gene expression and affect a variety of biological processes including cellular differentiation, immunological response, tumor development, and so on. Recently, microRNAs have been identified as promising disease biomarkers. In this work, we have fabricated a novel electrochemical method for ultrasensitive detection of microRNA. Generally, a DNA tetrahedron decorated gold electrode is employed as the recognition interface. Then, hybridizations between DNA tetrahedron, microRNA, and primer probe initiate rolling circle amplification (RCA) on the electrode surface. Silver nanoparticles attached to the RCA products provide significant electrochemical signals and a limit of detection as low as 50 aM is achieved. Moreover, homology microRNA family members with only one or two mismatches can be successfully distinguished. Therefore, this proposed method reveals great advancements toward improved disease diagnosis and prognosis.

  16. The Sacred Circle: a conceptual framework for spiritual care in hospice.

    PubMed

    Paton, L

    1996-01-01

    Hospice care has consistently recognized the need to integrate spiritual care into holistic plans of care for dying patients and their families. Designing and implementing spiritual care interventions can be potentially difficult for hospice practitioners who have not had specific training in theology or pastoral care. Matthew Fox, a theologian, has developed a model of spiritual development that utilizes an ecumenical, ethical framework that can be directly applied to the care of hospice patients and families. This model employs a Sacred Circle approach that begins with an emphasis upon the sense of awe and wonder (the Via Positiva), moves into the next cycle by recognizing problems and negative emotions (the Via Negativa), that then flows into the creative solutions to problems (the Via Creativa), which finally transforms the problem into a new level of understanding (the Via Transformativa).

  17. Dot-in-Circle Sign - A Diagnostic MRI Sign for "Madura Foot".

    PubMed

    Javed, Faiza; Nazir, Rashid; Sharma, Manoj; Yasir, Sanam; Babar, Sadia

    2017-03-01

    Mycetoma is a slowly progressive localised, granulomatous, subcutaneous tissue infection common among adult males aged 20 - 50 years. The causing agents include both bacteria (actinomycetoma) and fungi (eumycetoma). This chronic infection was described in literature as Madura foot and eventually mycetoma, due to its etiology. Early clinical diagnosis before the appearance of sinuses and grains (aggregates of organism surrounded by granulation tissue, which are discharged from the draining sinuses) is difficult. Early diagnosis is important due to the therapeutic implications. Although biopsy and microbiological cultures provide definitive diagnosis. Delay in diagnosis may lead to amputation of the affected part. The recently described "dot-in-circle" sign on magnetic resonance imaging (MRI) is easy to recognise and highly specific. We present a case of histologically proven mycetoma with characteristic MRI features.

  18. Rigid motions: Action-angles, relative cohomology and polynomials with roots on the unit circle

    NASA Astrophysics Data System (ADS)

    Françoise, J.-P.; Garrido, P. L.; Gallavotti, G.

    2013-03-01

    Revisiting canonical integration of the classical solid near a hyperbolic or elliptic uniform rotation, normal canonical coordinates p, q are constructed so that the Hamiltonian becomes a function ("normal form") of x+ = pq or of x- = p2 + q2: the two cases are treated simultaneously distinguishing them, respectively, by a label a = ±, in terms of various power series with coefficients which are shown to be polynomials in a variable r^2_a depending on the inertia moments. The normal forms are derived via the analysis of a relative cohomology problem and shown to be obtainable without reference to the construction of the normal coordinates via elliptic integrals (unlike the derivation of the normal coordinates p, q). Results and conjectures also emerge about the properties of the above polynomials and the location of their roots. In particular a class of polynomials with all roots on the unit circle arises.

  19. Reducing error vector magnitude of OFDM signals using threshold vector circle method

    NASA Astrophysics Data System (ADS)

    Wang, Jingqi; Wu, Qingqing; Wang, Dong; Zhang, Chunlei; Wu, Wen

    2016-10-01

    The main disadvantage of Orthogonal Frequency Division Multiplexing (OFDM) signal is the high peak-to-average power ratio (PAPR) which influences the system power efficiency and system performance in the presence of nonlinearities within the high power amplifier (HPA). The error vector magnitude (EVM) is one of the performance metrics by communications standards in OFDM system. In this paper, a novel PAPR reduction method from geometric angle analysis is proposed which keeps the EVM and bit-error-rate (BER) performance. In our method, a threshold vector circle is designed in frequency domain in order to adjust the amplitude and phase of the OFDM signal constellation points to near the ideal points. Simulation results show that PAPR of a QPSK modulated OFDM signal is reduced from 10.98dB to 7.502dB with an EVM reduction of 2.57%. This technique should vastly improve the performance of OFDM signal in communication system.

  20. Adapting Washington Circle performance measures for public sector substance abuse treatment systems.

    PubMed

    Garnick, Deborah W; Lee, Margaret T; Horgan, Constance M; Acevedo, Andrea

    2009-04-01

    The Washington Circle, a group focused on developing and disseminating performance measures for substance abuse services, developed three such measures for private health plans. In this article, we explore whether these measures are appropriate for meeting measurement goals in the public sector and feasible to calculate in the public sector using data collected for administrative purposes by state and local substance abuse and/or mental health agencies. Working collaboratively, 12 states specified revised measures and 6 states pilot tested them. Two measures were retained from the original specifications: initiation of treatment and treatment engagement. Additional measures were focused on continuity of care after assessment, detoxification, residential or inpatient care. These data demonstrate that state agencies can calculate performance measures from routinely available information and that there is wide variability in these indicators. Ongoing research is needed to examine the reasons for these results, which might include lack of patient interest or commitment, need for quality improvement efforts, or financial issues.

  1. Novel analytical methods for stratus OCT: alignment of the scan circle.

    PubMed

    Marín-Franch, Iván; Swanson, William H; Adams, Brittany R; Zhu, Haogang; Crabb, David P

    2012-12-01

    Measurement of retinal nerve fiber layer (RNFL) thickness using optical coherence tomography (OCT) is commonly used in the detection and management of glaucoma. The Stratus OCT (Carl Zeiss Meditec, Inc., Dublin, CA) is widely used, but image acquisition is subject to artifacts, such as those caused by normal fixational eye movements, and this leads to unreliable measurements. Novel analytical methods have been developed to estimate the amount of misalignment of the circular scanning protocol used by the Stratus OCT. A computer program with a graphical user interface implementing these methods has been written by some of the authors. A case example is presented in this report that shows the effect that vertical displacements of the OCT scan have on measured RNFL thickness. The example is used to demonstrate how the software can be used for estimating the positional alignment of the scan circle. This software can potentially improve the identification of unreliable RNFL thickness measurements and is freely available from the authors.

  2. Iris unwrapping using the Bresenham circle algorithm for real-time iris recognition

    NASA Astrophysics Data System (ADS)

    Carothers, Matthew T.; Ngo, Hau T.; Rakvic, Ryan N.; Broussard, Randy P.

    2015-02-01

    An efficient parallel architecture design for the iris unwrapping process in a real-time iris recognition system using the Bresenham Circle Algorithm is presented in this paper. Based on the characteristics of the model parameters this algorithm was chosen over the widely used polar conversion technique as the iris unwrapping model. The architecture design is parallelized to increase the throughput of the system and is suitable for processing an inputted image size of 320 × 240 pixels in real-time using Field Programmable Gate Array (FPGA) technology. Quartus software is used to implement, verify, and analyze the design's performance using the VHSIC Hardware Description Language. The system's predicted processing time is faster than the modern iris unwrapping technique used today∗.

  3. Virus Hunting: Discovery of New Episomal Circular Viruses by Rolling Circle Techniques.

    PubMed

    Vanmechelen, Bert; Rector, Annabel; Maes, Piet

    2017-02-06

    Many methods for the discovery of novel viruses are based on amplification of the virus using consensus or degenerate PCR primers. A downside of this approach is that it requires prior knowledge of the viral nucleotide sequence to be applicable. Presented in this unit is a method for the sequence-independent amplification of circular viral genomes that is based on the rolling-circle mechanism used by certain viruses in their natural replication cycle. The amplification of the virus of interest is coupled to the isolation of the viral genome by gel extraction following a restriction digestion. Once isolated, the sequence of the viral genome can be determined by nanopore sequencing, a rapid and inexpensive next-generation sequencing technology that generates long reads in real time. The method described in this unit was originally developed for the discovery of papillomaviruses, but can be used for the identification of all types of circular DNA viruses. © 2017 by John Wiley & Sons, Inc.

  4. Anatomical labeling of the circle of willis using maximum a posteriori graph matching.

    PubMed

    Robben, David; Sunaert, Stefan; Thijs, Vincent; Wilms, Guy; Maes, Frederik; Suetens, Paul

    2013-01-01

    A new method for anatomically labeling the vasculature is presented and applied to the Circle of Willis. Our method converts the segmented vasculature into a graph that is matched with an annotated graph atlas in a maximum a posteriori (MAP) way. The MAP matching is formulated as a quadratic binary programming problem which can be solved efficiently. Unlike previous methods, our approach can handle non tree-like vasculature and large topological differences. The method is evaluated in a leave-one-out test on MRA of 30 subjects where it achieves a sensitivity of 93% and a specificity of 85% with an average error of 1.5 mm on matching bifurcations in the vascular graph.

  5. A multiloop generalization of the circle criterion for stability margin analysis

    NASA Technical Reports Server (NTRS)

    Safonov, M. G.; Athans, M.

    1981-01-01

    In order to provide a theoretical tool well suited for use in characterizing the stability margins (e.g., gain and phase margins) of multiloop feedback systems, multiloop input-output stability results generalizing the circle stability criterion are considered. Generalized conic sectors with 'centers' and 'radii' determined by linear dynamical operators are employed to enable an engineer to specify the stability margins which he desires as a frequency-dependent convex set of modeling errors (including nonlinearities, gain variations, and phase variations) which the system must be able to tolerate in each feedback loop without instability. The resulting stability criterion gives sufficient conditions for closed-loop stability in the presence of such frequency-dependent modeling errors, even when the modeling errors occur simultaneously in all loops.

  6. Preparation of Small RNAs Using Rolling Circle Transcription and Site-Specific RNA Disconnection

    PubMed Central

    Wang, Xingyu; Li, Can; Gao, Xiaomeng; Wang, Jing; Liang, Xingguo

    2015-01-01

    A facile and robust RNA preparation protocol was developed by combining rolling circle transcription (RCT) with RNA cleavage by RNase H. Circular DNA with a complementary sequence was used as the template for promoter-free transcription. With the aid of a 2′-O-methylated DNA, the RCT-generated tandem repeats of the desired RNA sequence were disconnected at the exact end-to-end position to harvest the desired RNA oligomers. Compared with the template DNA, more than 4 × 103 times the amount of small RNA products were obtained when modest cleavage was carried out during transcription. Large amounts of RNA oligomers could easily be obtained by simply increasing the reaction volume. PMID:25584899

  7. Digital quantification of rolling circle amplified single DNA molecules in a resistive pulse sensing nanopore.

    PubMed

    Kühnemund, M; Nilsson, M

    2015-05-15

    Novel portable, sensitive and selective DNA sensor methods for bio-sensing applications are required that can rival conventionally used non-portable and expensive fluorescence-based sensors. In this paper, rolling circle amplification (RCA) products are detected in solution and on magnetic particles using a resistive pulse sensing (RPS) nanopore. Low amounts of DNA molecules are detected by padlock probes which are circularized in a strictly target dependent ligation reaction. The DNA-padlock probe-complex is captured on magnetic particles by sequence specific capture oligonucleotides and amplified by a short RCA. Subsequent RPS analysis is used to identify individual particles with single attached RCA products from blank particles. This proof of concept opens up for a novel non-fluorescent digital DNA quantification method that can have many applications in bio-sensing and diagnostic approaches.

  8. Observations with the Real Instituto y Observatorio de la Armada CCD transit circle in Argentina

    NASA Astrophysics Data System (ADS)

    Muiños, J. I.; Belizón, F.; Vallejo, M.; Mallamaci, C.; Pérez, J. A.

    The Real Instituto y Observatorio de la Armada (ROA) meridian circle was moved to the Estación de Altura Carlos Ulrrico Cesco in the República Argentina in 1996. Until November 1999 the observations were carried out with a moving slit micrometer. In spring 2001 the result of these observations has been published, forming the first Hispano-Argentinian Meridian Catalogue (HAMC). In December 1999 was installed a SpectraSource CCD camera of 1552×1024 pixels of 9 μ. The CCD camera observes in drift scan mode. A survey of the southern hemisphere is being observed from +3° to -60° of declination. In this contribution is presented a description of the telescope and the automatic control system, the results of observations carried out with the slit micrometer, and the observational and preliminary reduction techniques with the CCD camera, the present state of the southern hemisphere survey and the future possibilities.

  9. Posterior circulation ischemia in patients with fetal-type circle of Willis and hypoplastic vertebrobasilar system.

    PubMed

    Lochner, Piergiorgio; Golaszewski, Stefan; Caleri, Francesca; Ladurner, Gunther; Tezzon, Frediano; Zuccoli, Giulio; Nardone, Raffaele

    2011-12-01

    Little attention has been given to the fetal-type posterior circle of Willis (FTP) in the literature; also symptomatic basilar artery (BA) hypoplasia has been rarely reported. We aimed to illustrate that the association of a hypoplastic vertebrobasilar system (VBS) with the FTP may lead to posterior circulation ischemia. Magnetic resonance imaging and three-dimensional time-of-flight magnetic resonance angiography were performed in 88 consecutive patients with ischemic stroke or TIA in the VBS. Thirteen patients were identified with either stroke or TIA in the context of a hypoplastic VBS and a fetal origin of the posterior cerebral arteries. All patients had unilateral or bilateral FTP, hypoplastic BA and at least one hypoplastic vertebral artery. Transcranial color-coded duplex revealed decreased flow velocity and increased pulsatility index along the BA. A hypoplastic VBS may be accompanied by the FTP and its simultaneous occurrence can predispose to ischemic events in the posterior circulation.

  10. A multiloop generalization of the circle criterion for stability margin analysis

    NASA Technical Reports Server (NTRS)

    Safonov, M. G.; Athans, M.

    1979-01-01

    In order to provide a theoretical tool suited for characterizing the stability margins of multiloop feedback systems, multiloop input-output stability results generalizing the circle stability criterion are considered. Generalized conic sectors with 'centers' and 'radii' determined by linear dynamical operators are employed to specify the stability margins as a frequency dependent convex set of modeling errors (including nonlinearities, gain variations and phase variations) which the system must be able to tolerate in each feedback loop without instability. The resulting stability criterion gives sufficient conditions for closed loop stability in the presence of frequency dependent modeling errors, even when the modeling errors occur simultaneously in all loops. The stability conditions yield an easily interpreted scalar measure of the amount by which a multiloop system exceeds, or falls short of, its stability margin specifications.

  11. The Washington Circle continuity of care performance measure: Predictive validity with adolescents discharged from residential treatment

    PubMed Central

    Godley, Mark D.; Funk, Rodney R.; Lee, Margaret T.; Garnick, Deborah W.

    2009-01-01

    The current study examined the predictive validity of the Washington Circle (WC) continuity of care after long-term residential treatment performance measure, as well as the impact of assertive continuing care interventions on achieving continuity of care. This measure is a process measure that focuses on timely delivery of a minimal floor of services that are necessary to provide sufficient quality of treatment but should not be construed to be the optimal continuity of care after residential treatment for any specific adolescent. Participants included 342 adolescents who were admitted to long-term residential treatment and randomly assigned to either standard continuing care or an assertive continuing care condition. Overall, results provide initial support for the WC continuity of care after residential treatment performance measure as a useful predictor of 3-month recovery status. Additionally, assignment to an assertive continuing care condition was found to significantly increase the likelihood of achieving continuity of care. PMID:19553067

  12. Repressor logic modules assembled by rolling circle amplification platform to construct a set of logic gates

    PubMed Central

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

    2016-01-01

    Small molecule metabolites and their allosterically regulated repressors play an important role in many gene expression and metabolic disorder processes. These natural sensors, though valuable as good logic switches, have rarely been employed without transcription machinery in cells. Here, two pairs of repressors, which function in opposite ways, were cloned, purified and used to control DNA replication in rolling circle amplification (RCA) in vitro. By using metabolites and repressors as inputs, RCA signals as outputs, four basic logic modules were constructed successfully. To achieve various logic computations based on these basic modules, we designed series and parallel strategies of circular templates, which can further assemble these repressor modules in an RCA platform to realize twelve two-input Boolean logic gates and a three-input logic gate. The RCA-output and RCA-assembled platform was proved to be easy and flexible for complex logic processes and might have application potential in molecular computing and synthetic biology. PMID:27869177

  13. Effects of angular gain transformations between movement and visual feedback on coordination performance in unimanual circling

    PubMed Central

    Rieger, Martina; Dietrich, Sandra; Prinz, Wolfgang

    2014-01-01

    Tool actions are characterized by a transformation (of spatio-temporal and/or force-related characteristics) between movements and their resulting consequences in the environment. This transformation has to be taken into account, when planning and executing movements and its existence may affect performance. In the present study we investigated how angular gain transformations between movement and visual feedback during circling movements affect coordination performance. Participants coordinated the visual feedback (feedback dot) with a continuously circling stimulus (stimulus dot) on a computer screen in order to produce mirror symmetric trajectories of them. The movement angle was multiplied by a gain factor (0.5–2; nine levels) before it was presented on the screen. Thus, the angular gain transformations changed the spatio-temporal relationship between the movement and its feedback in visual space, and resulted in a non-constant mapping of movement to feedback positions. Coordination performance was best with gain = 1. With high gains the feedback dot was in lead of the stimulus dot, with small gains it lagged behind. Anchoring (reduced movement variability) occurred when the two trajectories were close to each other. Awareness of the transformation depended on the deviation of the gain from 1. In conclusion, the size of an angular gain transformation as well as its mere presence influence performance in a situation in which the mapping of movement positions to visual feedback positions is not constant. When designing machines or tools that involve transformations between movements and their external consequences, one should be aware that the mere presence of angular gains may result in performance decrements and that there can be flaws in the representation of the transformation. PMID:24634665

  14. From Fragments to a museum display: restoration of a Gautier meridian circle

    NASA Astrophysics Data System (ADS)

    Granato, Marcus

    2009-07-01

    The Museu de Astronomia e Ciências Afins (MAST), which opened to the public in 1985, is a research institute of the Brazilian Ministry of Science and Technology. One of its main activities is to preserve its collections, especially the most important one, its collection of scientific instruments, which grants MAST its identity as a museum of science and technology. Among the 2,000 objects in the collection there is a Gautier meridian circle that has a 190-mm diameter objective lens and a focal distance of 2,400 mm, with its axis aligned east-west. It should be noted that this instrument was at great risk of being lost to the collection, as it had been left dismantled since the 1960s, and the top part of the dome that sheltered it had been demolished in the 1980s, leaving just a vestibule and the base of the dome, which was in danger of completely collapsing. The intervention philosophy applied was not to put the instrument back in working order, but to allow it to be viewed and understood by the public within a coherent display space. As for the dome, a shelter was built for the instrument using a metal cover of a similar volume and appearance to the original, but with a different function, i.e. it is no longer designed to permit astronomical investigations, but rather to protect the exhibition space and merge harmoniously with the rest of the listed architectural complex. This paper presents information about the history of this meridian circle and its restoration, as well as about the Imperial Observatório do Rio de Janeiro/Observatório Nacional where this instrument was originally used.

  15. Delayed Triggering of Early Aftershocks by Multiple Waves Circling the Earth

    NASA Astrophysics Data System (ADS)

    Sullivan, B.; Peng, Z.

    2011-12-01

    It is well known that direct surface waves of large earthquakes are capable of triggering shallow earthquakes and deep tremor at long-range distances. Recent studies have shown that multiple surface waves circling the earth could also remotely trigger microearthquakes [Peng et al., 2011]. However, it is still not clear whether multiple surface waves returning back to the mainshock epicenters could also trigger/modulate aftershock activities. Here we conduct a study to search for evidence of such triggering by systematically examining aftershock activities of 20 magnitude-8-or-higher earthquakes since 1990 that are capable of producing surface waves circling the globe repeatedly. We compute the magnitude of completeness for each sequence, and stack all the sequences together to compute the seismicity and moment rates by sliding data windows. The sequences are also shuffled randomly and these rates are compared to the actual data as well as synthetic aftershock sequences to estimate the statistical significance of the results. We also compare them with varying stacks of magnitude 7-8 earthquakes to better understand the possible biases that could be introduced by our rate calculation method. Our preliminary results suggest that there is some moderate increase of early aftershock activity after a few hours when the surface waves return to the epicentral region. However, we could not completely rule out the possibility that such an increase is purely due to random fluctuations of aftershocks or caused by missing aftershocks in the first few hours after the mainshock. We plan to examine continuous waveform data of selected sequences to obtain a better understanding of the multiple surface waves and aftershock activity.

  16. Rolling-Circle Transposons Catalyze Genomic Innovation in a Mammalian Lineage

    PubMed Central

    Thomas, Jainy; Phillips, Caleb D.; Baker, Robert J.; Pritham, Ellen J.

    2014-01-01

    Rolling-circle transposons (Helitrons) are a newly discovered group of mobile DNA widespread in plant and invertebrate genomes but limited to the bat family Vespertilionidae among mammals. Little is known about the long-term impact of Helitron activity because the genomes where Helitron activity has been extensively studied are predominated by young families. Here, we report a comprehensive catalog of vetted Helitrons from the 7× Myotis lucifugus genome assembly. To estimate the timing of transposition, we scored presence/absence across related vespertilionid genome sequences with estimated divergence times. This analysis revealed that the Helibat family has been a persistent source of genomic innovation throughout the vespertilionid diversification from approximately 30–36 Ma to as recently as approximately 1.8–6 Ma. This is the first report of persistent Helitron transposition over an extended evolutionary timeframe. These findings illustrate that the pattern of Helitron activity is akin to the vertical persistence of LINE retrotransposons in primates and other mammalian lineages. Like retrotransposition in primates, rolling-circle transposition has generated lineage-specific variation and accounts for approximately 110 Mb, approximately 6% of the genome of M. lucifugus. The Helitrons carry a heterogeneous assortment of host sequence including retroposed messenger RNAs, retrotransposons, DNA transposons, as well as introns, exons and regulatory regions (promoters, 5′-untranslated regions [UTRs], and 3′-UTRs) of which some are evolving in a pattern suggestive of purifying selection. Evidence that Helitrons have contributed putative promoters, exons, splice sites, polyadenylation sites, and microRNA-binding sites to transcripts otherwise conserved across mammals is presented, and the implication of Helitron activity to innovation in these unique mammals is discussed. PMID:25223768

  17. Insect seasonality: circle map analysis of temperature-driven life cycles.

    PubMed

    Powell, James A; Logan, Jesse A

    2005-05-01

    Maintaining an adaptive seasonality, with life cycle events occurring at appropriate times of year and in synchrony with cohorts and ephemeral resources, is a basic ecological requisite for many cold-blooded organisms. There are many mechanisms for synchronizing developmental milestones, such as egg laying (oviposition), egg hatching, cocoon opening, and the emergence of adults. These are often irreversible, specific to particular life stages, and include diapause, an altered physiological state which can be reversed by some synchronizing environmental cue (e.g. photoperiod). However, many successful organisms display none of these mechanisms for maintaining adaptive seasonality. In this paper, we briefly review the mathematical relationship between environmental temperatures and developmental timing and discuss the consequences of viewing these models as circle maps from the cycle of yearly oviposition dates and temperatures to oviposition dates for subsequent generations. Of particular interest biologically are life cycles which are timed to complete in exactly 1 year, or univoltine cycles. Univoltinism, associated with reproductive success for many temperate species, is related to stable fixed points of the developmental circle map. Univoltine fixed points are stable and robust in broad temperature bands, but lose stability suddenly to maladaptive cycles at the edges of these bands. Adaptive seasonality may therefore break down with little warning with constantly increasing or decreasing temperature change, as in scenarios for global warming. These ideas are illustrated and explored in the context of Mountain Pine Beetle (Dendroctonus ponderosae Hopkins) occurring in the marginal thermal habitat of central Idaho's Rocky Mountains. Applications of these techniques have not been widely explored by the applied math community, but are likely to provide great insight into the response of biological systems to climate change.

  18. Rolling-circle transposons catalyze genomic innovation in a mammalian lineage.

    PubMed

    Thomas, Jainy; Phillips, Caleb D; Baker, Robert J; Pritham, Ellen J

    2014-09-14

    Rolling-circle transposons (Helitrons) are a newly discovered group of mobile DNA widespread in plant and invertebrate genomes but limited to the bat family Vespertilionidae among mammals. Little is known about the long-term impact of Helitron activity because the genomes where Helitron activity has been extensively studied are predominated by young families. Here, we report a comprehensive catalog of vetted Helitrons from the 7× Myotis lucifugus genome assembly. To estimate the timing of transposition, we scored presence/absence across related vespertilionid genome sequences with estimated divergence times. This analysis revealed that the Helibat family has been a persistent source of genomic innovation throughout the vespertilionid diversification from approximately 30-36 Ma to as recently as approximately 1.8-6 Ma. This is the first report of persistent Helitron transposition over an extended evolutionary timeframe. These findings illustrate that the pattern of Helitron activity is akin to the vertical persistence of LINE retrotransposons in primates and other mammalian lineages. Like retrotransposition in primates, rolling-circle transposition has generated lineage-specific variation and accounts for approximately 110 Mb, approximately 6% of the genome of M. lucifugus. The Helitrons carry a heterogeneous assortment of host sequence including retroposed messenger RNAs, retrotransposons, DNA transposons, as well as introns, exons and regulatory regions (promoters, 5'-untranslated regions [UTRs], and 3'-UTRs) of which some are evolving in a pattern suggestive of purifying selection. Evidence that Helitrons have contributed putative promoters, exons, splice sites, polyadenylation sites, and microRNA-binding sites to transcripts otherwise conserved across mammals is presented, and the implication of Helitron activity to innovation in these unique mammals is discussed.

  19. Correlation of Fos expression and circling asymmetry during gerbil vestibular compensation

    NASA Technical Reports Server (NTRS)

    Kaufman, G. D.; Shinder, M. E.; Perachio, A. A.

    1999-01-01

    Vestibular compensation is a central nervous system process resulting in recovery of functional movement and control following a unilateral vestibular lesion. Small pressure injections of phosphorothioate 20mer oligonucleotides were used to probe the role of the Fos transcription protein during vestibular compensation in the gerbil brainstem. During isoflurane gas anesthesia, antisense probes against the c-fos mRNA sequence were injected into the medial vestibular and prepositus nuclei unilaterally prior to a unilateral surgical labyrinthectomy. Anionic dyes, which did not interact with the oligonucleotides, were used to mark the injection site and help determine the extent of diffusion. The antiFos oligonucleotide injections reduced Fos expression at the injection site in neurons which normally express Fos after the lesion, and also affected circling behavior induced by hemilabyrinthectomy. With both ipsilateral and contralateral medial vestibular and prepositus nuclei injections, less ipsilateral and more contralateral circling was noted in animals injected with antiFos injections as compared to non-injected controls. The degree of change in these behaviors was dependent upon the side of the injection. Histologically, antiFos injections reduced the number of Fos immunolabeled neurons around the injection site, and increased Fos expression contralaterally. The correlation of the number of neurons with Fos expression to turning behavior was stronger for contralateral versus ipsilateral turns, and for neurons in the caudal and ipsilateral sub-regions of the medial vestibular and prepositus nuclei. The results are discussed in terms of neuronal firing activity versus translational activity based on the asymmetrical expression of the Fos inducible transcription factor in the medial vestibular and prepositus nuclei. Although ubiquitous in the brain, transcription factors like Fos can serve localized and specific roles in sensory-specific adaptive stimuli. Antisense

  20. The Use of "Circle of Friends" Strategy to Improve Social Interactions and Social Acceptance: A Case Study of a Child with Asperger's Syndrome and Other Associated Needs

    ERIC Educational Resources Information Center

    O'Connor, Eileen

    2016-01-01

    The study outlined here was an attempt to examine the use of "Circle of Friends" as a single intervention approach in addressing the issue of inappropriate social interactions in a child with Asperger Syndrome. The child selected was in a mainstream setting, as the main feature of a circle of friends is peers supporting peers. The child…