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Sample records for chromatid cohesion required

  1. Identification of protein complexes required for efficient sister chromatid cohesion

    NARCIS (Netherlands)

    Mayer, Melanie L; Pot, Isabelle; Chang, Michael; Xu, Hong; Aneliunas, Victoria; Kwok, Teresa; Newitt, Rick; Aebersold, Ruedi; Boone, Charles; Brown, Grant W; Hieter, Philip

    2004-01-01

    Ctf8p is a component of Ctf18-RFC, an alternative replication factor C-like complex required for efficient sister chromatid cohesion in Saccharomyces cerevisiae. We performed synthetic genetic array (SGA) analysis with a ctf8 deletion strain as a primary screen to identify other nonessential genes r

  2. Cohesin SMC1 beta is required for meiotic chromosome dynamics, sister chromatid cohesion and DNA recombination

    NARCIS (Netherlands)

    Revenkova, E.; Eijpe, M.; Heyting, C.; Hodges, C.A.; Hunt, P.A.; Liebe, B.; Scherthan, H.; Jessberger, R.

    2004-01-01

    Sister chromatid cohesion ensures the faithful segregation of chromosomes in mitosis and in both meiotic divisions1, 2, 3, 4. Meiosis-specific components of the cohesin complex, including the recently described SMC1 isoform SMC15, were suggested to be required for meiotic sister chromatid cohesion a

  3. The MCM-binding protein ETG1 aids sister chromatid cohesion required for postreplicative homologous recombination repair.

    Directory of Open Access Journals (Sweden)

    Naoki Takahashi

    2010-01-01

    Full Text Available The DNA replication process represents a source of DNA stress that causes potentially spontaneous genome damage. This effect might be strengthened by mutations in crucial replication factors, requiring the activation of DNA damage checkpoints to enable DNA repair before anaphase onset. Here, we demonstrate that depletion of the evolutionarily conserved minichromosome maintenance helicase-binding protein ETG1 of Arabidopsis thaliana resulted in a stringent late G2 cell cycle arrest. This arrest correlated with a partial loss of sister chromatid cohesion. The lack-of-cohesion phenotype was intensified in plants without functional CTF18, a replication fork factor needed for cohesion establishment. The synergistic effect of the etg1 and ctf18 mutants on sister chromatid cohesion strengthened the impact on plant growth of the replication stress caused by ETG1 deficiency because of inefficient DNA repair. We conclude that the ETG1 replication factor is required for efficient cohesion and that cohesion establishment is essential for proper development of plants suffering from endogenous DNA stress. Cohesion defects observed upon knockdown of its human counterpart suggest an equally important developmental role for the orthologous mammalian ETG1 protein.

  4. The Cohesin Subunit Rad21 Is Required for Synaptonemal Complex Maintenance, but Not Sister Chromatid Cohesion, during Drosophila Female Meiosis

    Science.gov (United States)

    Lehner, Christian F.; Heidmann, Stefan K.

    2014-01-01

    Replicated sister chromatids are held in close association from the time of their synthesis until their separation during the next mitosis. This association is mediated by the ring-shaped cohesin complex that appears to embrace the sister chromatids. Upon proteolytic cleavage of the α-kleisin cohesin subunit at the metaphase-to-anaphase transition by separase, sister chromatids are separated and segregated onto the daughter nuclei. The more complex segregation of chromosomes during meiosis is thought to depend on the replacement of the mitotic α-kleisin cohesin subunit Rad21/Scc1/Mcd1 by the meiotic paralog Rec8. In Drosophila, however, no clear Rec8 homolog has been identified so far. Therefore, we have analyzed the role of the mitotic Drosophila α-kleisin Rad21 during female meiosis. Inactivation of an engineered Rad21 variant by premature, ectopic cleavage during oogenesis results not only in loss of cohesin from meiotic chromatin, but also in precocious disassembly of the synaptonemal complex (SC). We demonstrate that the lateral SC component C(2)M can interact directly with Rad21, potentially explaining why Rad21 is required for SC maintenance. Intriguingly, the experimentally induced premature Rad21 elimination, as well as the expression of a Rad21 variant with destroyed separase consensus cleavage sites, do not interfere with chromosome segregation during meiosis, while successful mitotic divisions are completely prevented. Thus, chromatid cohesion during female meiosis does not depend on Rad21-containing cohesin. PMID:25101996

  5. A matter of choice: the establishment of sister chromatid cohesion

    OpenAIRE

    Uhlmann, Frank

    2009-01-01

    Sister chromatid cohesion is the basis for the recognition of chromosomal DNA replication products for their bipolar segregation in mitosis. Fundamental to sister chromatid cohesion is the ring-shaped cohesin complex, which is loaded onto chromosomes long before the initiation of DNA replication and is thought to hold replicated sister chromatids together by topological embrace. What happens to cohesin when the replication fork approaches, and how cohesin recognizes newly synthesized sister c...

  6. Meiotic sister chromatid cohesion and recombination in two filamentous fungi

    NARCIS (Netherlands)

    Heemst, van D.

    2000-01-01

    Homologous recombination and sister chromatid cohesion play important roles in the maintenance of genome integrity and the fidelity of chromosome segregation in mitosis and meiosis. Within the living cell, the integrity of the DNA is threatened by various factors that cause DNA-lesions, of which DNA

  7. Meiotic sister chromatid cohesion and recombination in two filamentous fungi

    OpenAIRE

    Heemst, van, D.

    2000-01-01

    Homologous recombination and sister chromatid cohesion play important roles in the maintenance of genome integrity and the fidelity of chromosome segregation in mitosis and meiosis. Within the living cell, the integrity of the DNA is threatened by various factors that cause DNA-lesions, of which DNA double-strand breaks (DSBs) are considered particularly deleterious. The causative agents can be of endogenous origin, such as metabolically produced free radicals, and of exogenous origin, such a...

  8. Meiosis-specific cohesin component, Stag3 is essential for maintaining centromere chromatid cohesion, and required for DNA repair and synapsis between homologous chromosomes.

    Directory of Open Access Journals (Sweden)

    Jessica Hopkins

    2014-07-01

    Full Text Available Cohesins are important for chromosome structure and chromosome segregation during mitosis and meiosis. Cohesins are composed of two structural maintenance of chromosomes (SMC1-SMC3 proteins that form a V-shaped heterodimer structure, which is bridged by a α-kleisin protein and a stromal antigen (STAG protein. Previous studies in mouse have shown that there is one SMC1 protein (SMC1β, two α-kleisins (RAD21L and REC8 and one STAG protein (STAG3 that are meiosis-specific. During meiosis, homologous chromosomes must recombine with one another in the context of a tripartite structure known as the synaptonemal complex (SC. From interaction studies, it has been shown that there are at least four meiosis-specific forms of cohesin, which together with the mitotic cohesin complex, are lateral components of the SC. STAG3 is the only meiosis-specific subunit that is represented within all four meiosis-specific cohesin complexes. In Stag3 mutant germ cells, the protein level of other meiosis-specific cohesin subunits (SMC1β, RAD21L and REC8 is reduced, and their localization to chromosome axes is disrupted. In contrast, the mitotic cohesin complex remains intact and localizes robustly to the meiotic chromosome axes. The instability of meiosis-specific cohesins observed in Stag3 mutants results in aberrant DNA repair processes, and disruption of synapsis between homologous chromosomes. Furthermore, mutation of Stag3 results in perturbation of pericentromeric heterochromatin clustering, and disruption of centromere cohesion between sister chromatids during meiotic prophase. These defects result in early prophase I arrest and apoptosis in both male and female germ cells. The meiotic defects observed in Stag3 mutants are more severe when compared to single mutants for Smc1β, Rec8 and Rad21l, however they are not as severe as the Rec8, Rad21l double mutants. Taken together, our study demonstrates that STAG3 is required for the stability of all meiosis

  9. UBL5 is essential for pre-mRNA splicing and sister chromatid cohesion in human cells

    DEFF Research Database (Denmark)

    Oka, Yasuyoshi; Varmark, Hanne; Vitting-Seerup, Kristoffer;

    2014-01-01

    UBL5 is an atypical ubiquitin-like protein, whose function in metazoans remains largely unexplored. We show that UBL5 is required for sister chromatid cohesion maintenance in human cells. UBL5 primarily associates with spliceosomal proteins, and UBL5 depletion decreases pre-mRNA splicing efficiency......, leading to globally enhanced intron retention. Defective sister chromatid cohesion is a general consequence of dysfunctional pre-mRNA splicing, resulting from the selective downregulation of the cohesion protection factor Sororin. As the UBL5 yeast orthologue, Hub1, also promotes spliceosome functions...

  10. SNW1 enables sister chromatid cohesion by mediating the splicing of sororin and APC2 pre-mRNAs

    Science.gov (United States)

    van der Lelij, Petra; Stocsits, Roman R; Ladurner, Rene; Petzold, Georg; Kreidl, Emanuel; Koch, Birgit; Schmitz, Julia; Neumann, Beate; Ellenberg, Jan; Peters, Jan-Michael

    2014-01-01

    Although splicing is essential for the expression of most eukaryotic genes, inactivation of splicing factors causes specific defects in mitosis. The molecular cause of this defect is unknown. Here, we show that the spliceosome subunits SNW1 and PRPF8 are essential for sister chromatid cohesion in human cells. A transcriptome-wide analysis revealed that SNW1 or PRPF8 depletion affects the splicing of specific introns in a subset of pre-mRNAs, including pre-mRNAs encoding the cohesion protein sororin and the APC/C subunit APC2. SNW1 depletion causes cohesion defects predominantly by reducing sororin levels, which causes destabilisation of cohesin on DNA. SNW1 depletion also reduces APC/C activity and contributes to cohesion defects indirectly by delaying mitosis and causing “cohesion fatigue”. Simultaneous expression of sororin and APC2 from intron-less cDNAs restores cohesion in SNW1-depleted cells. These results indicate that the spliceosome is required for mitosis because it enables expression of genes essential for cohesion. Our transcriptome-wide identification of retained introns in SNW1- and PRPF8-depleted cells may help to understand the aetiology of diseases associated with splicing defects, such as retinosa pigmentosum and cancer. PMID:25257309

  11. Defective sister chromatid cohesion is synthetically lethal with impaired APC/C function

    OpenAIRE

    De Lange, Job; Faramarz, Atiq; Oostra, Anneke B.; Menezes, Renee X.; van der Meulen, Ida H.; Rooimans, Martin A.; Rockx, Davy A.; Brakenhoff, Ruud H.; van Beusechem, Victor W; King, Randall W; Winter, Johan P. de; Wolthuis, Rob M. F.

    2015-01-01

    Warsaw breakage syndrome (WABS) is caused by defective DDX11, a DNA helicase that is essential for chromatid cohesion. Here, a paired genome-wide siRNA screen in patient-derived cell lines reveals that WABS cells do not tolerate partial depletion of individual APC/C subunits or the spindle checkpoint inhibitor p31comet. A combination of reduced cohesion and impaired APC/C function also leads to fatal mitotic arrest in diploid RPE1 cells. Moreover, WABS cell lines, and several cancer cell line...

  12. SNW1 enables sister chromatid cohesion by mediating the splicing of sororin and APC2 pre-mRNAs

    OpenAIRE

    van der Lelij, Petra; Stocsits, Roman R; Ladurner, Rene; Petzold, Georg; Kreidl, Emanuel; Koch, Birgit; Schmitz, Julia; Neumann, Beate; Ellenberg, Jan; Peters, Jan-Michael

    2014-01-01

    Although splicing is essential for the expression of most eukaryotic genes, inactivation of splicing factors causes specific defects in mitosis. The molecular cause of this defect is unknown. Here, we show that the spliceosome subunits SNW1 and PRPF8 are essential for sister chromatid cohesion in human cells. A transcriptome-wide analysis revealed that SNW1 or PRPF8 depletion affects the splicing of specific introns in a subset of pre-mRNAs, including pre-mRNAs encoding the cohesion protein s...

  13. SGO1 maintains bovine meiotic and mitotic centromeric cohesions of sister chromatids and directly affects embryo development.

    Directory of Open Access Journals (Sweden)

    Feng-Xia Yin

    Full Text Available Shugoshin (SGO is a critical factor that enforces cohesion from segregation of paired sister chromatids during mitosis and meiosis. It has been studied mainly in invertebrates. Knowledge of SGO(s in a mammalian system has only been reported in the mouse and Hela cells. In this study, the functions of SGO1 in bovine oocytes during meiotic maturation, early embryonic development and somatic cell mitosis were investigated. The results showed that SGO1 was expressed from germinal vesicle (GV to the metaphase II stage. SGO1 accumulated on condensed and scattered chromosomes from pre-metaphase I to metaphase II. The over-expression of SGO1 did not interfere with the process of homologous chromosome separation, although once separated they were unable to move to the opposing spindle poles. This often resulted in the formation of oocytes with 60 replicated chromosomes. Depletion of SGO1 in GV oocytes affected chromosomal separation resulting in abnormal chromosome alignment at a significantly higher proportion than in control oocytes. Knockdown of SGO1 expression significantly decreased the embryonic developmental rate and quality. To further confirm the function(s of SGO1 during mitosis, bovine embryonic fibroblast cells were transfected with SGO1 siRNAs. SGO1 depletion induced the premature dissociation of chromosomal cohesion at the centromere and along the chromosome arm giving rise to abnormal appearing mitotic patterns. The results of this study infer that SGO1 is involved in the centromeric cohesion of sister chromatids and chromosomal movement towards the spindle poles. Depletion of SGO1 causes arrestment of cell division in meiosis and mitosis.

  14. Mechanics of Sister Chromatids studied with a Polymer Model

    Directory of Open Access Journals (Sweden)

    Yang eZhang

    2013-10-01

    Full Text Available Sister chromatid cohesion denotes the phenomenon that sister chromatids are initially attached to each other in mitosis to guarantee the error-free distribution into the daughter cells. Cohesion is mediated by binding proteins and only resolved after mitotic chromosome condensation is completed. However, the amount of attachement points required to maintain sister chromatid cohesion while still allowing proper chromosome condensation is not known yet. Additionally the impact of cohesion on the mechanical properties of chromosomes also poses an interesting problem. In this work we study the conformational and mechanical properties of sister chromatids by means of computer simulations. We model both protein-mediated cohesion between sister chromatids and chromosome condensation with a dynamic binding mechanisms. We show in a phase diagram that only specific link concentrations lead to connected and fully condensed chromatids that do not intermingle with each other nor separate due to entropic forces. Furthermore we show that dynamic bonding between chromatids decrease the Young's modulus compared to non-bonded chromatids.

  15. Rec8p, a meiotic recombination and sister chromatid cohesion phosphoprotein of the Rad21p family conserved from fision yeast to humans.

    OpenAIRE

    Parisi, S.; McKay, Michael; Molnar, M; Thompson, Anne; van der Spek, Peter; Drunen-Schoenmaker, E.; Kanaar, Roland; Lehmann, E.; Hoeijmakers, Jan; Kohli, J

    1999-01-01

    textabstractOur work and that of others defined mitosis-specific (Rad21 subfamily) and meiosis-specific (Rec8 subfamily) proteins involved in sister chromatid cohesion in several eukaryotes, including humans. Mutation of the fission yeast Schizosaccharomyces pombe rec8 gene was previously shown to confer a number of meiotic phenotypes, including strong reduction of recombination frequencies in the central region of chromosome III, absence of linear element polymerization, reduced pairing of h...

  16. Increased sister chromatid cohesion and DNA damage response factor localization at an enzyme-induced DNA double-strand break in vertebrate cells.

    LENUS (Irish Health Repository)

    Dodson, Helen

    2009-10-01

    The response to DNA damage in vertebrate cells involves successive recruitment of DNA signalling and repair factors. We used light microscopy to monitor the genetic dependencies of such localization to a single, induced DNA double strand break (DSB) in vertebrate cells. We used an inducible version of the rare-cutting I-SceI endonuclease to cut a chromosomally integrated I-SceI site beside a Tet operator array that was visualized by binding a Tet repressor-GFP fusion. Formation of gamma-H2AX foci at a single DSB was independent of ATM or Ku70. ATM-deficient cells showed normal kinetics of 53Bp1 recruitment to DSBs, but Rad51 localization was retarded. 53Bp1 and Rad51 foci formation at a single DSB was greatly reduced in H2AX-null DT40 cells. We also observed decreased inter-sister chromatid distances after DSB induction, suggesting that cohesin loading at DSBs causes elevated sister chromatid cohesion. Loss of ATM reduced DSB-induced cohesion, consistent with cohesin being an ATM target in the DSB response. These data show that the same genetic pathways control how cells respond to single DSBs and to multiple lesions induced by whole-cell DNA damage.

  17. The SUMO protease SENP1 is required for cohesion maintenance and mitotic arrest following spindle poison treatment

    Energy Technology Data Exchange (ETDEWEB)

    Era, Saho [Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, IFOM-IEO campus, Via Adamello 16, 20139 Milan (Italy); Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501 (Japan); Abe, Takuya; Arakawa, Hiroshi [Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, IFOM-IEO campus, Via Adamello 16, 20139 Milan (Italy); Kobayashi, Shunsuke [Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501 (Japan); Szakal, Barnabas [Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, IFOM-IEO campus, Via Adamello 16, 20139 Milan (Italy); Yoshikawa, Yusuke; Motegi, Akira; Takeda, Shunichi [Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501 (Japan); Branzei, Dana, E-mail: dana.branzei@ifom.eu [Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, IFOM-IEO campus, Via Adamello 16, 20139 Milan (Italy)

    2012-09-28

    Highlights: Black-Right-Pointing-Pointer SENP1 knockout chicken DT40 cells are hypersensitive to spindle poisons. Black-Right-Pointing-Pointer Spindle poison treatment of SENP1{sup -/-} cells leads to increased mitotic slippage. Black-Right-Pointing-Pointer Mitotic slippage in SENP1{sup -/-} cells associates with apoptosis and endoreplication. Black-Right-Pointing-Pointer SENP1 counteracts sister chromatid separation during mitotic arrest. Black-Right-Pointing-Pointer Plk1-mediated cohesion down-regulation is involved in colcemid cytotoxicity. -- Abstract: SUMO conjugation is a reversible posttranslational modification that regulates protein function. SENP1 is one of the six SUMO-specific proteases present in vertebrate cells and its altered expression is observed in several carcinomas. To characterize SENP1 role in genome integrity, we generated Senp1 knockout chicken DT40 cells. SENP1{sup -/-} cells show normal proliferation, but are sensitive to spindle poisons. This hypersensitivity correlates with increased sister chromatid separation, mitotic slippage, and apoptosis. To test whether the cohesion defect had a causal relationship with the observed mitotic events, we restored the cohesive status of sister chromatids by introducing the TOP2{alpha}{sup +/-} mutation, which leads to increased catenation, or by inhibiting Plk1 and Aurora B kinases that promote cohesin release from chromosomes during prolonged mitotic arrest. Although TOP2{alpha} is SUMOylated during mitosis, the TOP2{alpha}{sup +/-} mutation had no obvious effect. By contrast, inhibition of Plk1 or Aurora B rescued the hypersensitivity of SENP1{sup -/-} cells to colcemid. In conclusion, we identify SENP1 as a novel factor required for mitotic arrest and cohesion maintenance during prolonged mitotic arrest induced by spindle poisons.

  18. The SUMO protease SENP1 is required for cohesion maintenance and mitotic arrest following spindle poison treatment

    International Nuclear Information System (INIS)

    Highlights: ► SENP1 knockout chicken DT40 cells are hypersensitive to spindle poisons. ► Spindle poison treatment of SENP1−/− cells leads to increased mitotic slippage. ► Mitotic slippage in SENP1−/− cells associates with apoptosis and endoreplication. ► SENP1 counteracts sister chromatid separation during mitotic arrest. ► Plk1-mediated cohesion down-regulation is involved in colcemid cytotoxicity. -- Abstract: SUMO conjugation is a reversible posttranslational modification that regulates protein function. SENP1 is one of the six SUMO-specific proteases present in vertebrate cells and its altered expression is observed in several carcinomas. To characterize SENP1 role in genome integrity, we generated Senp1 knockout chicken DT40 cells. SENP1−/− cells show normal proliferation, but are sensitive to spindle poisons. This hypersensitivity correlates with increased sister chromatid separation, mitotic slippage, and apoptosis. To test whether the cohesion defect had a causal relationship with the observed mitotic events, we restored the cohesive status of sister chromatids by introducing the TOP2α+/− mutation, which leads to increased catenation, or by inhibiting Plk1 and Aurora B kinases that promote cohesin release from chromosomes during prolonged mitotic arrest. Although TOP2α is SUMOylated during mitosis, the TOP2α+/− mutation had no obvious effect. By contrast, inhibition of Plk1 or Aurora B rescued the hypersensitivity of SENP1−/− cells to colcemid. In conclusion, we identify SENP1 as a novel factor required for mitotic arrest and cohesion maintenance during prolonged mitotic arrest induced by spindle poisons.

  19. Regulation of the Drosophila Enhancer of split and invected-engrailed gene complexes by sister chromatid cohesion proteins.

    Directory of Open Access Journals (Sweden)

    Cheri A Schaaf

    Full Text Available The cohesin protein complex was first recognized for holding sister chromatids together and ensuring proper chromosome segregation. Cohesin also regulates gene expression, but the mechanisms are unknown. Cohesin associates preferentially with active genes, and is generally absent from regions in which histone H3 is methylated by the Enhancer of zeste [E(z] Polycomb group silencing protein. Here we show that transcription is hypersensitive to cohesin levels in two exceptional cases where cohesin and the E(z-mediated histone methylation simultaneously coat the entire Enhancer of split and invected-engrailed gene complexes in cells derived from Drosophila central nervous system. These gene complexes are modestly transcribed, and produce seven of the twelve transcripts that increase the most with cohesin knockdown genome-wide. Cohesin mutations alter eye development in the same manner as increased Enhancer of split activity, suggesting that similar regulation occurs in vivo. We propose that cohesin helps restrain transcription of these gene complexes, and that deregulation of similarly cohesin-hypersensitive genes may underlie developmental deficits in Cornelia de Lange syndrome.

  20. Cohesin acetyltransferase Esco2 is a cell viability factor and is required for cohesion in pericentric heterochromatin

    OpenAIRE

    Whelan, Gabriela; Kreidl, Emanuel; Wutz, Gordana; Egner, Alexander; Peters, Jan-Michael; Eichele, Gregor

    2012-01-01

    Sister chromatid cohesion, mediated by cohesin and regulated by Sororin, is essential for chromosome segregation. In mammalian cells, cohesion establishment and Sororin recruitment to chromatin‐bound cohesin depends on the acetyltransferases Esco1 and Esco2. Mutations in Esco2 cause Roberts syndrome, a developmental disease in which mitotic chromosomes have a ‘railroad’ track morphology. Here, we show that Esco2 deficiency leads to termination of mouse development at pre‐ and post‐implantatio...

  1. Pds5B is required for cohesion establishment and Aurora B accumulation at centromeres

    OpenAIRE

    Carretero, María; Ruiz-Torres, Miguel; Rodríguez-Corsino, Miriam; Barthelemy, Isabel; Losada, Ana

    2013-01-01

    Cohesin mediates sister chromatid cohesion and contributes to the organization of interphase chromatin through DNA looping. In vertebrate somatic cells, cohesin consists of Smc1, Smc3, Rad21, and either SA1 or SA2. Three additional factors Pds5, Wapl, and Sororin bind to cohesin and modulate its dynamic association with chromatin. There are two Pds5 proteins in vertebrates, Pds5A and Pds5B, but their functional specificity remains unclear. Here, we demonstrate that Pds5 proteins are essential...

  2. Sgo1 is required for co-segregation of sister chromatids during achiasmate meiosis I

    OpenAIRE

    Dudas, Andrej; Ahmad, Shazia; Gregan, Juraj

    2011-01-01

    The reduction of chromosome number during meiosis is achieved by two successive rounds of chromosome segregation, called meiosis I and meiosis II. While meiosis II is similar to mitosis in that sister kinetochores are bi-oriented and segregate to opposite poles, recombined homologous chromosomes segregate during the first meiotic division. Formation of chiasmata, mono-orientation of sister kinetochores and protection of centromeric cohesion are three major features of meiosis I chromosomes wh...

  3. Rmi1, a member of the Sgs1–Top3 complex in budding yeast, contributes to sister chromatid cohesion

    OpenAIRE

    Lai, Mong Sing; Seki, Masayuki; Ui, Ayako; Enomoto, Takemi

    2007-01-01

    The Saccharomyces cerevisiae RecQ-mediated genome instability (Rmi1) protein was recently identified as the third member of the slow growth suppressor 1–DNA topoisomerase III (Sgs1–Top3) complex, which is required for maintaining genomic stability. Here, we show that cells lacking RMI1 have a mitotic delay, which is partly dependent on the spindle checkpoint, and are sensitive to the microtubule depolymerizing agent benomyl. We show that rmi1 and top3 single mutants are defective in sister ch...

  4. Sister chromatid exchanges

    International Nuclear Information System (INIS)

    Sister chromatid exchanges (SCEs) are cytological manifestations of DNA double-strand breakage and rejoining at homologous sites between the two chromatids of a chromosome. The occurrence of SCEs was deduced from the transformation of small ring chromosomes to large ring chromosomes following cell division. Using tritiated thymidine as marker and microautoradiography for detection, others demonstrated the occurrence of SCEs from the silver grain pattern on the sister chromatids. This method was eventually replaced by cytochemical methods. One showed that if cells were grown in medium containing 5-bromo-deoxyuridine (BrdUrd) for two cycles, the sister chromatids can be distinguished by the differential quenching of the fluorescence of the fluorochrome Hoechst 33258. Reduced staining with Giemsa stain of the BrdUrd-incorporated chromatids was also found to be useful in differentiating sister chromatids. The authors review in this chapter only those studies which have implications on the origin of SCEs

  5. Cohesin without cohesion: a novel role for Pds5 in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Kevin Tong

    Full Text Available High fidelity chromosome segregation during mitosis requires that cells identify the products of DNA replication during S-phase and then maintain that identity until anaphase onset. Sister chromatid identity is achieved through cohesin complexes (Smc1, Smc3, and Mcd1 and Irr1/Scc3, but the structure through which cohesins perform this task remains enigmatic. In the absence of unambiguous data, a popular model is that a subset of cohesin subunits form a huge ring-like structure that embraces both sister chromatids. This 'one-ring two-sister chromatid embrace' model makes clear predictions--including that premature cohesion loss in mitotic cells must occur through a substantial reduction in cohesin-DNA associations. We used chromatin immunoprecipitation to directly test for cohesin dissociation from well-established cohesin binding sites in mitotic cells inactivated for Pds5--a key cohesin regulatory protein. The results reveal little if any chromatin dissociation from cohesins, despite a regimen that produces both massive loss of sister chromatid tethering and cell inviability. We further excluded models that cohesion loss in mitotic cells inactivated for Pds5 arises through either cohesin subunit degradation, premature Hos1-dependent Smc3 de-acetylation or Rad61/WAPL-dependent regulation of cohesin dynamics. In combination, our findings support a model that cohesin complexes associate with each sister and that sister chromatid cohesion likely results from cohesin-cohesin interactions. We further assessed the role that Pds5 plays in cohesion establishment during S-phase. The results show that Pds5 inactivation can result in establishment defects despite normal cohesion loading and Smc3 acetylation, revealing a novel establishment role for Pds5 that is independent of these processes. The combination of findings provides important new insights that significantly impact current models of both cohesion establishment reactions and maintenance.

  6. Age-related aneuploidy through cohesion exhaustion

    OpenAIRE

    Jessberger, Rolf

    2012-01-01

    Pregnancy in older women is problematic, as oocytes are particularly prone to chromosome missegregation, and aneuploidy increases with age. Sister chromatid cohesion is weakened or lost with age, having a major impact in age-dependent aneuploidy, as discussed here.

  7. 40 CFR 79.65 - In vivo sister chromatid exchange assay.

    Science.gov (United States)

    2010-07-01

    ... references should be consulted. (1) 40 CFR 798.5915, In vivo Sister Chromatid Exchange Assay. (2) Kato, H... 40 Protection of Environment 16 2010-07-01 2010-07-01 false In vivo sister chromatid exchange... PROGRAMS (CONTINUED) REGISTRATION OF FUELS AND FUEL ADDITIVES Testing Requirements for Registration §...

  8. Energy-dependent cell cohesion in myxobacteria.

    OpenAIRE

    Gilmore, D F; White, D

    1985-01-01

    Cohesion in the myxobacterium Stigmatella aurantiaca was characterized. Two classes of cohesion were revealed, termed class A and class B. Class A cohesion is a characteristic of vegetative cells grown in tryptone or casitone (Difco Laboratories, Detroit, Mich.), whereas class B cohesion requires the addition of calcium ion for induction. Class A cohesion occurs in the presence of any cation and is temperature independent. Class B cohesion requires the presence of a cation in the calcium grou...

  9. Distance from cohesive end site cos determines the replication requirement for recombination in phage lambda.

    OpenAIRE

    Stahl, F. W.; KOBAYASHI, I.; Stahl, M M

    1982-01-01

    Previous work showed that crossing-over in the middle of the chromosome of phage lambda requires more DNA replication than does crossing-over near the termini. Relocation of cos, the sequence that determines the lambda termini, alters the requirements for replication in a given marked interval, demonstrating that distance from cos determines the amount of DNA replication that is required for genetic exchange. This result supports a break and copy mechanism for recombination mediated by the re...

  10. [Cohesion inside eu- and heterochromatin in human cells].

    Science.gov (United States)

    Cherepaninets, V D; Zhironkina, O A; Strelkova, O S; Kurchashova, S Iu; Kireev, I I

    2015-01-01

    It is considered that sister chromatids are held together immediately after replication by special protein complex--cohesin that consists of Smc1--Smc3 core dimer and two additional subunits, Scc1 and Scc3. This process is called cohesion. We have characterized binding of cohesin complex to early- and late-replicated chromatin at different stages of the cell cycle in human cells HeLa and HT1080 using superresolution microscopy (based on Structural ilumination microscopy--SIM) and immunoelectron microscopy. It has been shown that cohesins do not play important role in cohesion of heterochromatic domains, but they provide cohesion and organization of subdomains in euchromatic regions. PMID:25872375

  11. Mechanisms of sister chromatid recombination

    International Nuclear Information System (INIS)

    Studies using T948 as a model system have been carried out aimed at elucidating the mechanism of sister chromatid recombination (SCR). Characterization of U.V. light- and x-ray-induced SCR, the relationiship between SCR induction and DNA repair using rad mutations, and the relationship between SCR induction and the time of cell division using cdc mutations are presented. It has been supposed that SCR is induced at the phase of S-G2 following DNA replication, that postreplication break of DNA strands is strongly involved in the induction of SCR, and that induction type of SCR, i.e., conversion type or recombination type, is dependent upon the type of molecular damage of DNA. (Namekawa, K.)

  12. The budding yeast protein Chl1p is required to preserve genome integrity upon DNA damage in S-phase

    OpenAIRE

    Laha, Suparna; Das, Shankar Prasad; Hajra, Sujata; Sau, Soumitra; Sinha, Pratima

    2006-01-01

    The budding yeast protein, Chl1p, is required for sister-chromatid cohesion, transcriptional silencing, rDNA recombination and aging. In this work, we show that Chl1p is also required for viability when DNA replication is stressed, either due to mutations or if cells are treated with genotoxic agents like methylmethane sulfonate (MMS) and ultraviolet (UV) rays. The chl1 mutation caused synthetic growth defects with mutations in DNA replication genes. At semi-permissive temperatures, the doubl...

  13. Regions & Cohesion

    OpenAIRE

    KOFF, Harlan; Maganda, Carmen

    2012-01-01

    The journal of the Consortium for Comparative Research on Regional Integration and Social Cohesion (RISC), a cross-regional, interdisciplinary, and multi-lingual network of socially conscious and prestigious research institutes in Europe, North America, South America, Africa, and Asia. Due to the dramatic changes in global affairs related to regional integration, studies can no longer be limited to the analysis of economic competitiveness and political power in global geopolitics. Regions and...

  14. Multiple subunits of the Caenorhabditis elegans anaphase-promoting complex are required for chromosome segregation during meiosis I.

    OpenAIRE

    Davis, Edward S.; Wille, Lucia; Chestnut, Barry A.; Sadler, Penny L.; Shakes, Diane C; Golden, Andy

    2002-01-01

    Two genes, originally identified in genetic screens for Caenorhabditis elegans mutants that arrest in metaphase of meiosis I, prove to encode subunits of the anaphase-promoting complex or cyclosome (APC/C). RNA interference studies reveal that these and other APC/C subunits are essential for the segregation of chromosomal homologs during meiosis I. Further, chromosome segregation during meiosis I requires APC/C functions in addition to the release of sister chromatid cohesion.

  15. Territorial Cohesion Indicators for Sustainability and Economic Breakthrough

    OpenAIRE

    Agita Livina; Visvaldis Valtenbergs

    2013-01-01

    The analysis of large internal disparities between metropolitan regions and rural regions of European Union NUTS III level shows relevance of territorial cohesion Territorial cohesion requires integrated approach in regional planning and regional development. Therefore assessing progress towards territorial cohesion is a demanding task. In this report we are examining indicators of territorial cohesion using four themes that are usually associated with territorial cohesion - environmental res...

  16. Chromatid interchanges at intrachromosomal telomeric DNA sequences

    International Nuclear Information System (INIS)

    Chinese hamster Don cells were exposed to X-rays, mitomycin C and teniposide (VM-26) to induce chromatid exchanges (quadriradials and triradials). After fluorescence in situ hybridization (FISH) of telomere sequences it was found that interstitial telomere-like DNA sequence arrays presented around five times more breakage-rearrangements than the genome overall. This high recombinogenic capacity was independent of the clastogen, suggesting that this susceptibility is not related to the initial mechanisms of DNA damage. (author)

  17. Psychological characteristics of group cohesion athletes.

    Directory of Open Access Journals (Sweden)

    Sheriff Sarhan

    2011-07-01

    Full Text Available The basic components of group cohesion in sport teams. An analysis of publications on cohesion within the groups where an interconnection of individual goals of each participant group with common goals and the end result of teamwork. The concept of harmony in the team sports, where the rate of group cohesion is dependent on such integrative index as psychological climate. It is established that a number of athletes to achieve high results require high cohesion, unity, value-normative orientation, deep identification and responsibility for the results of the joint group activities.

  18. Cohesion: a new perspective

    OpenAIRE

    Braun, Daniel G.

    1983-01-01

    Recently the U.S. Army has recognized the benefits to combat effectiveness and retention associated with building cohesion in small units and has established programs intended to build cohesion. These programs have focused on small units in the combat arms and rely primarily on building cohesion through increased continuity of the unit's personnel. Research has established the significance of homogeneity of work group members in the building of cohesion in work groups. This research devel...

  19. Cohesion Policy Contributing to Territorial Cohesion: Future Scenarios

    NARCIS (Netherlands)

    Faludi, A.; Peyrony, J.

    2011-01-01

    The Barca Report advocates for developmental policies to be ‘place-based’: integrated as far as they affect ‘places’. The debate on territorial cohesion is equally concerned with integrating relevant policies and actions. This requires well-established democratic institutions and adequate responses

  20. Promoting Community Cohesion in England

    Science.gov (United States)

    Morris, Andrew B.; McDaid, Maggie; Potter, Hugh

    2011-01-01

    Following serious disturbances in some northern cities in England in 2001, concerns about possible rising inter-communal tension have led to a statutory duty to promote community cohesion being placed on schools. Inspectors from the Office for Standards in Education (Ofsted) are required to make judgements in the leadership and management section…

  1. Dynamics of Cohesive Sediments

    DEFF Research Database (Denmark)

    Johansen, Claus

    The present thesis considers the transport processes of cohesive sediments. The cohesive sediment used in the laboratory experiments was kaolinite, a clay mineral, in order to be able to reproduce the individual experiments. In the first part of the thesis, the theoretical considerations regarding...

  2. Diversity and Social Cohesion

    Science.gov (United States)

    Pagani, Camilla

    2014-01-01

    The issue of diversity, in its broadest sense, is discussed here in its relation to social cohesion, cross-cultural relations, ingroup-outgroup relations and educational interventions. The main thesis of the paper is that real social cohesion in an ingroup rests on the acknowledgment of and the dialog with the diversities of the members of the…

  3. Social cohesion in Europe

    NARCIS (Netherlands)

    Reverda, Nol

    2010-01-01

    This chapter explores the current discussions and policies towards social exclusion and cohesion in Europe. In a first section will briefly be identified how the wording in the social work discourse changed from originally the thinking in terms of poverty to the ideas of social cohesion nowadays. Th

  4. Cohesion in real materials

    International Nuclear Information System (INIS)

    Theoretically calculated values of cohesion force density are compared with their values in real materials. Cohesion at the interface of twin inclusions in niobium at 4.2 K, slip bands in niobium at 77 K, slip bands in niobium oxidized and predeformed at 295 K after cooling down to 77 K, in slip bands of different hardened and tempered steels, at the boundaries of Al99.999 grains - in the process of torsional vibrations at 523 K, have been determined. To calculate cohesion force density and dry friction coefficient a two-member formula of dry friction is used. In all the cases cohesion force density of real materials was below its values calculated theoretically. Excess of yield limit and strengthening curve under compression over yield limit and strengthening curve under tension is explaind as a result of summation and subtraction of external stresses and cohesion forces

  5. Homologous recombination, sister chromatid cohesion, and chromosome condensation in mammalian meiosis

    NARCIS (Netherlands)

    Eijpe, M.

    2002-01-01

    In the life cycle of sexually reproducing eukaryotes, haploid and diploid generations of cells alternate. Two types of cell division occur in such a life cycle: mitosis and meiosis. They are compared in chapter 1 . Haploid and diploid cells can multiply by mitoses.

  6. The origin recognition complex links replication, sister chromatid cohesion and transcriptional silencing in Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Suter, Bernhard; Tong, Amy; Chang, Michael; Yu, Lisa; Brown, Grant W; Boone, Charles; Rine, Jasper

    2004-01-01

    Mutations in genes encoding the origin recognition complex (ORC) of Saccharomyces cerevisiae affect initiation of DNA replication and transcriptional repression at the silent mating-type loci. To explore the function of ORC in more detail, a screen for genetic interactions was undertaken using large

  7. Relating Cohesive Zone Model to Linear Elastic Fracture Mechanics

    Science.gov (United States)

    Wang, John T.

    2010-01-01

    The conditions required for a cohesive zone model (CZM) to predict a failure load of a cracked structure similar to that obtained by a linear elastic fracture mechanics (LEFM) analysis are investigated in this paper. This study clarifies why many different phenomenological cohesive laws can produce similar fracture predictions. Analytical results for five cohesive zone models are obtained, using five different cohesive laws that have the same cohesive work rate (CWR-area under the traction-separation curve) but different maximum tractions. The effect of the maximum traction on the predicted cohesive zone length and the remote applied load at fracture is presented. Similar to the small scale yielding condition for an LEFM analysis to be valid. the cohesive zone length also needs to be much smaller than the crack length. This is a necessary condition for a CZM to obtain a fracture prediction equivalent to an LEFM result.

  8. Redefining Cohesiveness in Groups.

    Science.gov (United States)

    Keyton, Joann; Springston, Jeff

    1990-01-01

    Attempted to replicate and extend research on work of Kelly and Duran in assessing relationship of group member perceptions of group interaction to group effectiveness. Concludes perceived similarity may not always align with perceptions of cohesiveness. (Author/ABL)

  9. Regression with network cohesion

    OpenAIRE

    Li, Tianxi; Levina, Elizaveta; Zhu, Ji

    2016-01-01

    Prediction problems typically assume the training data are independent samples, but in many modern applications samples come from individuals connected by a network. For example, in adolescent health studies of risk-taking behaviors, information on the subjects' social networks is often available and plays an important role through network cohesion, the empirically observed phenomenon of friends behaving similarly. Taking cohesion into account in prediction models should allow us to improve t...

  10. Institutional Capacity for Territorial Cohesion

    OpenAIRE

    Van Well, Lisa

    2011-01-01

    Territorial cohesion has its legal basis in the Treaty of Lisbon and is one of the overarching goals in the 2007-2013 Cohesion Policy instruments. Still the definition of territorial cohesion can be characterized as a ‘moving target’ - each EU Member State and region conceptualizes the policy goal in as befits the specific regional challenges and opportunities of the territory. The thesis examines the concept of territorial cohesion as a normative goal that is intended to be implemented at va...

  11. Cohesion Policy Contributing to Territorial Cohesion – Future Scenarios

    Directory of Open Access Journals (Sweden)

    Andreas Faludi

    2011-09-01

    Full Text Available The Barca Report advocates for developmental policies to be ‘place-based’: integrated as far as they affect ‘places’. The debate on territorial cohesion is equally concerned with integrating relevant policies and actions. This requires well-established democratic institutions and adequate responses to the demands of technical systems and of markets. Following Lisbeth Hooghe and Gary Marks, the respective arrangements are described as Governance Type I and Type II. All levels of government, including that of the EU, partake in both types, but relations between them are problematic, particularly in the context of Europe 2020: Will this EU strategy be mainly a matter for Directorate-Generals and their various clients pursuing their policies (Governance Type II, or will Cohesion policy, with its more integrated and decentralised approach, involving many levels of government and stakeholders (Governance Type I form platforms for integrating them? This paper presents four scenarios; each based on a combination of strong/weak Governance Type I and Type II, which are labelled as the ‘Anglo-Saxon’, ‘Saint-Simonian’, ‘Rhineland’ and the ‘European’ Scenarios. The authors prefer the latter, but the best one can hope for in the short term is for this option not to fall by the wayside.

  12. Adhesion and Cohesion

    Directory of Open Access Journals (Sweden)

    J. Anthony von Fraunhofer

    2012-01-01

    Full Text Available The phenomena of adhesion and cohesion are reviewed and discussed with particular reference to dentistry. This review considers the forces involved in cohesion and adhesion together with the mechanisms of adhesion and the underlying molecular processes involved in bonding of dissimilar materials. The forces involved in surface tension, surface wetting, chemical adhesion, dispersive adhesion, diffusive adhesion, and mechanical adhesion are reviewed in detail and examples relevant to adhesive dentistry and bonding are given. Substrate surface chemistry and its influence on adhesion, together with the properties of adhesive materials, are evaluated. The underlying mechanisms involved in adhesion failure are covered. The relevance of the adhesion zone and its importance with regard to adhesive dentistry and bonding to enamel and dentin is discussed.

  13. Enhanced chromatid damage in blood lymphocytes after G2 phase x irradiation, a marker of the ataxia-telangiectasia gene

    International Nuclear Information System (INIS)

    An assay for ataxia-telangiectasia (A-T) heterozygotes, i.e., healthy carriers of the A-T gene(s), requiring only a small sample (3.5 mL) of peripheral blood, is described. Frequencies of chromatid aberrations in phytohemagglutinin-stimulated blood lymphocytes collected by demecolcine from 0.5 hour to 1.5 hours after x irradiation with 58 roentgens were twofold to threefold higher in A-T heterozygotes than in clinically normal controls and twofold to three-fold higher in A-T patients (homozygotes) than in A-T gene carriers. The persistence of chromatid breaks and gaps in lymphocytes following radiation-induced DNA damage during G2 suggests a deficiency or deficiencies in DNA repair that may be the defect at the molecular level that results in the enhanced radiosensitivity and cancer proneness characterizing A-T gene carriers and patients

  14. Competition and social cohesion

    OpenAIRE

    Mario Libertini

    2014-01-01

    "Competition" and "social cohesion" are both protected by E.U. and Italian laws. The author moves from the analysis of the meaning of these two concepts, in order to reflect on their compatibility and the way to conciliate them. The central problem - in the opinion of the Author - is to abandon the myth of spontaneous markets' order and to rebuild a political order able to maintain and support, as far as possible, the competitive market economy, but also to govern economic processes in critic...

  15. Diversity, Inclusiveness and Social Cohesion

    OpenAIRE

    Staveren, Irene; Zahid PERVAIZ; A. R. Chaudhary

    2013-01-01

    markdownabstract__Abstract__ This study aims to investigate the role of diversity (ethnic, linguistic and religious) and social inequality in determining social cohesion. By using cross-country data, we have found that social inequality may be more important factor than diversity in determining cohesiveness of a society. Our analysis suggests that inclusive societies may be in better position to cope with the possible threat of diversity for social cohesion. By reducing social inequality, soc...

  16. Social cohesion matters in health

    OpenAIRE

    Chuang, Ying-Chih; Chuang, Kun-Yang; Yang, Tzu-Hsuan

    2013-01-01

    Introduction The concept of social cohesion has invoked debate due to the vagueness of its definition and the limitations of current measurements. This paper attempts to examine the concept of social cohesion, develop measurements, and investigate the relationship between social cohesion and individual health. Methods This study used a multilevel study design. The individual-level samples from 29 high-income countries were obtained from the 2000 World Value Survey (WVS) and the 2002 European ...

  17. Document Cohesion Flow: Striving towards Coherence

    NARCIS (Netherlands)

    Crossley, Scott; Dascalu, Mihai; Trausan-Matu, Stefan; Allen, Laura; McNamara, Danielle

    2016-01-01

    Text cohesion is an important element of discourse processing. This paper presents a new approach to modeling, quantifying, and visualizing text cohesion using automated cohesion flow indices that capture semantic links among paragraphs. Cohesion flow is calculated by applying Cohesion Network Analy

  18. Unit cohesion and social structure

    OpenAIRE

    MuΣnoz, Jorge Alberto.

    1995-01-01

    Unit cohesion at the primary-group level has been an enduring concern of the Department of Defense since the Viet Nam conflict. This effort studies the antecedent causal factors impinging on the primary-group cohesion within the context of a political mov

  19. Immigration, social cohesion, and naturalization

    DEFF Research Database (Denmark)

    Lægaard, Sune

    2010-01-01

    The standard appeal to social cohesion in relation to immigration concerns admittance and residence. But social cohesion is sometimes also invoked as a relevant concern in relation to the attainment of citizenship in the state through naturalization. Many western states have recently tightened...

  20. Demythologising social cohesion: Towards a practical theological vision

    Directory of Open Access Journals (Sweden)

    Stephanus F. de Beer

    2014-08-01

    Full Text Available This article considers the topical issue of social cohesion. It seeks to demythologise the issuebringing it into critical conversation with eight related categories. It proposes that a vision ofa socially cohesive society should employ all eight categories as parallel and complementarystrategies. Secondly, it proposes a practical theological vision of social cohesion that will notonly embrace these eight categories but will root itself in a spirituality of the table, informedby a vision of the oikos of God, seeking shalom in the oikos and doing so through four strategicmoments of engagement.Intradisciplinary and/or interdisciplinary implications: This article indicates that socialcohesion requires an integrated approach of different strategies, not competing butcomplementing each other. Social cohesion requires interdisciplinary, intradisciplinary andtransdisciplinary research and action. For example, exploring ways in which land redistributioninhibits or contributes to social cohesion requires multiple stakeholders and disciplinesdiscerning together. The proposed practical theological vision implies new categories to beincluded in curricula and practical theological discourse for it to contribute meaningfully notonly to the current debate but also to practices fostering a socially cohesive society.

  1. The role of biophysical cohesion on subaqueous bed form size

    Science.gov (United States)

    Parsons, Daniel R.; Schindler, Robert J.; Hope, Julie A.; Malarkey, Jonathan; Baas, Jaco H.; Peakall, Jeffrey; Manning, Andrew J.; Ye, Leiping; Simmons, Steve; Paterson, David M.; Aspden, Rebecca J.; Bass, Sarah J.; Davies, Alan G.; Lichtman, Ian D.; Thorne, Peter D.

    2016-02-01

    Biologically active, fine-grained sediment forms abundant sedimentary deposits on Earth's surface, and mixed mud-sand dominates many coasts, deltas, and estuaries. Our predictions of sediment transport and bed roughness in these environments presently rely on empirically based bed form predictors that are based exclusively on biologically inactive cohesionless silt, sand, and gravel. This approach underpins many paleoenvironmental reconstructions of sedimentary successions, which rely on analysis of cross-stratification and bounding surfaces produced by migrating bed forms. Here we present controlled laboratory experiments that identify and quantify the influence of physical and biological cohesion on equilibrium bed form morphology. The results show the profound influence of biological cohesion on bed form size and identify how cohesive bonding mechanisms in different sediment mixtures govern the relationships. The findings highlight that existing bed form predictors require reformulation for combined biophysical cohesive effects in order to improve morphodynamic model predictions and to enhance the interpretations of these environments in the geological record.

  2. RSC Facilitates Rad59-Dependent Homologous Recombination between Sister Chromatids by Promoting Cohesin Loading at DNA Double-Strand Breaks ▿

    OpenAIRE

    Oum, Ji-Hyun; Seong, Changhyun; Kwon, YoungHo; Ji, Jae-Hoon; Sid, Amy; Ramakrishnan, Sreejith; Ira, Grzegorz; Malkova, Anna; Sung, Patrick; Lee, Sang Eun; Shim, Eun Yong

    2011-01-01

    Homologous recombination repairs DNA double-strand breaks by searching for, invading, and copying information from a homologous template, typically the homologous chromosome or sister chromatid. Tight wrapping of DNA around histone octamers, however, impedes access of repair proteins to DNA damage. To facilitate DNA repair, modifications of histones and energy-dependent remodeling of chromatin are required, but the precise mechanisms by which chromatin modification and remodeling enzymes cont...

  3. Rtt107 phosphorylation promotes localisation to DNA double-stranded breaks (DSBs and recombinational repair between sister chromatids.

    Directory of Open Access Journals (Sweden)

    Pranav Ullal

    Full Text Available Efficient repair of DNA double-stranded breaks (DSB requires a coordinated response at the site of lesion. Nucleolytic resection commits repair towards homologous recombination, which preferentially occurs between sister chromatids. DSB resection promotes recruitment of the Mec1 checkpoint kinase to the break. Rtt107 is a target of Mec1 and serves as a scaffold during repair. Rtt107 plays an important role during rescue of damaged replication forks, however whether Rtt107 contributes to the repair of DSBs is unknown. Here we show that Rtt107 is recruited to DSBs induced by the HO endonuclease. Rtt107 phosphorylation by Mec1 and its interaction with the Smc5-Smc6 complex are both required for Rtt107 loading to breaks, while Rtt107 regulators Slx4 and Rtt101 are not. We demonstrate that Rtt107 has an effect on the efficiency of sister chromatid recombination (SCR and propose that its recruitment to DSBs, together with the Smc5-Smc6 complex is important for repair through the SCR pathway.

  4. DNA-mediated transfer of a human DNA repair gene that controls sister chromatid exchange.

    OpenAIRE

    Thompson, L H; Brookman, K W; Minkler, J L; Fuscoe, J C; Henning, K A; Carrano, A V

    1985-01-01

    The Chinese hamster cell line mutant EM9, which has a reduced ability to repair DNA strand breaks, is noted for its highly elevated frequency of sister chromatid exchange, a property shared with cells from individuals with Bloom's syndrome. The defect in EM9 cells was corrected by fusion hybridization with normal human fibroblasts and by transfection with DNA from hybrid cells. The transformants showed normalization of sister chromatid exchange frequency but incomplete correction of the repai...

  5. Forms of cohesion in confinement institutions

    Directory of Open Access Journals (Sweden)

    Ekaterina D. Slobodenyuk

    2015-12-01

    Full Text Available Objective to identify the diversity of cohesion forms in confinement institutions. Methods qualitative analyses based on indepth semistructured interviews. Results the study included adaptation of Western methodologies of the cohesion phenomenon analysis to the Russian reality and operationalization of the moral bases of group cohesion. This served as the bases for designing a guide for indepth semistructured interviews 10 interviews were conducted with people recently released from general and strict regime colonies. Content analysis of the interviews revealed a number of structural sections that demonstrate the diversity of cohesion forms alongside with one that is most meaningful to the prisoners and therefore the most well perceived and articulated by respondents. Analysis of the latter allowed to identify a set of groups showing different degree and nature of cohesion. By the degree of cohesion one can identify the poorly cohesive groups quotloutsquot moderately cohesive quotredsquot quotthievesquot and highly cohesive quotfightersquot. By the nature of cohesion in the prisonersrsquo community there are both groups united on the basis of social morality quotredsquot quotthievesquot and groups demonstrating a high degree of cohesion based on the social justice morality quotfightersquot. A detailed analysis of the latter group also showed that the cohesion can have both traits of morality social justice and features of social order moral. Scientific novelty using the sociopsychological theory of the moral motives in determining the bases of cohesion. Practical significance the research results can be applied for the development of sociopsychological techniques for the penal system reform.

  6. Separase Is Required for Homolog and Sister Disjunction during Drosophila melanogaster Male Meiosis, but Not for Biorientation of Sister Centromeres.

    OpenAIRE

    Blattner, Ariane C.; Soumya Chaurasia; McKee, Bruce D.; Lehner, Christian F.

    2016-01-01

    Spatially controlled release of sister chromatid cohesion during progression through the meiotic divisions is of paramount importance for error-free chromosome segregation during meiosis. Cohesion is mediated by the cohesin protein complex and cleavage of one of its subunits by the endoprotease separase removes cohesin first from chromosome arms during exit from meiosis I and later from the pericentromeric region during exit from meiosis II. At the onset of the meiotic divisions, cohesin has ...

  7. Flocculation Dynamics of cohesive sediment

    NARCIS (Netherlands)

    Maggi, F.

    2005-01-01

    Cohesive sediment suspended in natural waters is subject not only to transport and deposition processes but also to reactions of flocculation, \\textit{i.e.} aggregation of fine particles, and breakup of aggregates. Although aggregation and breakup occur at small and very small length scales compared

  8. Employability Development Teams: Cohesion Factors

    Science.gov (United States)

    Johnson, Douglas W.; Munger, Paul F.

    1972-01-01

    In this study the researchers attempted to analyze the factors of age, sex, racial-ethnic background, operational life of the team, educational status, leader status, team size, caseload size, and the location of program site in terms of their potential effects upon team cohesion. (Author)

  9. Developing Indicators of Territorial Cohesion

    DEFF Research Database (Denmark)

    Gallina, Andrea; Farrugia, Nadia

    (EU). The objective of territorial cohesion, which builds on the European Spatial Development Perspective (ESDP), is to help achieve a more balanced development by reducing existing disparities, avoiding territorial imbalances and by making sectoral policies, which have a spatial impact and regional...

  10. Auto consolidated cohesive sediments erosion

    International Nuclear Information System (INIS)

    Pollutants and suspended matters of a river can accumulate into the sedimentary column. Once deposited, they are submitted to self-weight consolidation processes, ageing and burying, leading to an increase of their erosion resistance. Pollutant fluxes can be related to sedimentary fluxes, determined by threshold laws. In this work, an erosion threshold model is suggested by introducing a cohesion force into the usual force balance. A model of cohesion is developed on the basis of interactions between argillaceous cohesive particles (clays), particularly the Van der Waals force, whose parameterization is ensured by means of granulometry and porosity. Artificial erosion experiments were performed in a recirculating erosion flume with natural cored sediments where critical shear stress measurements were performed. Other analyses provided granulometry and porosity. The results obtained constitute a good database for the literature. The model is then applied to the experimental conditions and gives good agreement with measurements. An example of the accounting for self-weight consolidation processes is finally suggested, before finishing on a Mohr like diagram dedicated to soft cohesive sediment erosion. (author)

  11. INTERCO - Indicators of territorial cohesion. Final Report

    OpenAIRE

    Dao, Quoc-Hy; Plagnat Cantoreggi, Pauline; Rousseaux, Vanessa; Angelidis, Minas; Batzikou, Spyridoula; Bazoula, Vivian; Tsigkas, Epameinontas; van Well, Lisa; Sterling, José; Schürmann, Carsten; Böhme, Kai; Gloersen, Erik; Brockett, Susan

    2012-01-01

    32 Top Indicators for 6 Territorial Cohesion Priorities. INTERCO- Indicators of Territorial Cohesion- delivers valuable input for policy makers and scientist interested in indicators for territorial cohesion. The analytical framework developed by the research team proved to be applicable and successful in revealing the existing spatial disparities and territorial cohesion trends in Europe and can be used by policy makers at different levels. According to the Final Report, the main results sho...

  12. Does Social Cohesion Really Promote Reforms?

    OpenAIRE

    Andréasson, Hannes; Elert, Niklas; Karlson, Nils

    2013-01-01

    This paper investigates whether social cohesion makes economic reforms more likely. First, we investigated whether social cohesion is a coherent concept by using a principal-component factor (PCF) analysis covering 16 indicators used to measure social cohesion in the previous literature for 40 different countries. The results suggested that in fact social cohesion is a multidimensional concept, consisting of no less than five orthogonal components or distinct dimensions, which we labeled soci...

  13. Analysis of textual Cohesion in News Report

    Institute of Scientific and Technical Information of China (English)

    刘盛兰

    2014-01-01

    Cohesion embodies the non-structural resources in English discourse and indicates the latent continuity existing in the text.On the basis of cohesion theory,this paper analyzes textual cohesion of the selected news reports form BBC website,in order to explore the way of structuring the text and realizing the meaning of the text.

  14. Analysis of Cohesion inOliver Twist

    Institute of Scientific and Technical Information of China (English)

    程文文

    2016-01-01

    Cohesion is an important concept in the study of stylistics. This thesis aims to study the applications of cohesion in the Charles Dicken’ world-famous novelOliver Twist, including both the grammatical and lexical cohesive devices in the work.

  15. Sister chromatid exchange assay as a predictor of tumor chemoresponse.

    Science.gov (United States)

    Mourelatos, D

    2016-06-01

    Sister Chromatid Exchanges (SCEs) are known to enhance as a consequence of exposure to various mutagenic agents and appear to indicate DNA damaging effects and/or subsequent repair by homologous recombination (HR). DNA damage plays an interesting role in the majority of mechanisms underlying the effects of antitumor drugs, since the genetic activity of the plethora of these agents is due to their ability to damage the DNA. The DNA-effects of antitumor agents towards normal cells (genotoxicity) are great drawbacks of antitumor therapy and are connected to important adverse health effects in cancer patients undergoing chemotherapy. On the other hand, failure of chemotherapy in many cases is due to the DNA repair ability which cancer, like normal cells, also possess. As both DNA repair and genotoxic exposure are expected to vary among patients, correlating SCEs frequencies with only individual repair capacity may be feasible to predict. Cancer risk has not been observed to be associated with high SCEs levels. Since the administration of effective antitumor drugs with limited adverse effects is of great importance in the success of anticancer therapy, a lot of interest has been directed toward the development of methods and approaches that would enable the correct selection of appropriate drugs prior to the initiation of therapy on an individual basis. To this effect, more than 30 years ago, an investigation of the ability of the in vitro and the in vivo SCEs-assay to predict the in vitro and in vivo sensitivity of tumor cells to newly synthesized drugs or to those already in use began. In this short review a critical appraisal of the SCEs-assay as an important biomarker used for predicting cancer chemo-response as well as a summary of the key findings from several studies published within the last 20 years in this field is performed. PMID:27265374

  16. DNA crosslinking, sister-chromatid exchange and specific-locus mutations.

    Science.gov (United States)

    Carrano, A V; Thompson, L H; Stetka, D G; Minkler, J L; Mazrimas, J A; Fong, S

    1979-11-01

    Chinese hamster ovary cells were treated with the DNA-crosslinking chemicals, mitomycin C (MMC) and porfiromycin (POR), and their monofunctional derivative decarbamoyl mitomycin C (DCMMC). After exposure, the cells were studied for the induction of sister-chromatid exchanges (SCEs) and mutations at the hypoxanthine phosphoribosyltransferase and adenine phosphoribosyltransferase loci. The frequency of SCEs varied significantly in successive sampling intervals, requiring the weighting of each interval by the percentage of second-division mitosis in that interval to obtain the mean SCE frequency for each dose. All 3 compounds were potent inducers of SCEs but weakly mutagenic. All 3 chemicals by concentration were approximately equally effective in inducing SCEs or mutations. When the induced SCEs and mutations were compared at equal levels of survival, DCMMC was slightly more effective than MMC or POR in inducing SCEs and somewhat less mutagenic. These results indicate that the DNA interstrand crosslink is not the major lesion responsible for the induction of SCE or mutation by these compounds. PMID:522865

  17. DNA crosslinking, sister-chromatid exchange and specific-locus mutations

    Energy Technology Data Exchange (ETDEWEB)

    Carrano, A.V.; Thompson, L.H.; Stetka, D.G.; Minkler, J.L.; Mazrimas, J.A.; Fong, S.

    1979-01-01

    Chinese hamster ovary cells were treated with the DNA-crosslinking chemicals, mitomycin C (MMC) and porfiromycin (POR), and their monofunctional derivative decarbamoyl mitomycin C (DCMMC). After exposure, the cells were studied for the induction of sister-chromatid exchanges (SCEs) and mutations at the hypoxanthine phosphoribosyltransferase and adenine phosphoribosyltransferase loci. The frequency of SCEs varied significantly in successive sampling intervals, requiring the weighting of each interval by the percentage of second-division mitosis in that interval to obtain the mean SCE frequency for each dose. All 3 compounds were potent inducers of SCEs but weakly mutagenic. All 3 chemicals by concentration were approximately equally effective in inducing SCEs or mutations. When the induced SCEs and mutations were compared at equal levels of survival, DCMMC was slightly more effective than MMC or POR in inducing SCEs and somewhat less mutagenic. These results indicate that the DNA interstrand crosslink is not the major lesion responsible for the induction of SCE or mutation by these compounds.

  18. The cohesiveness of sourcing teams

    DEFF Research Database (Denmark)

    Lidegaard, Nina

    2015-01-01

    Sourcing teams are introduced as an approach to achieving the interdepartmental integration necessary for companies to address the complexity of strategic sourcing. Companies aim at facilitating teams capable of balancing the goals and tasks of the team with departmental expectations; however, th...... cohesiveness is introduced as an explanatory factor and, consequently, linkages between team cohesiveness and team performance are proposed.......Sourcing teams are introduced as an approach to achieving the interdepartmental integration necessary for companies to address the complexity of strategic sourcing. Companies aim at facilitating teams capable of balancing the goals and tasks of the team with departmental expectations; however, the...... practical implementation is often unsuccessful leading to poor performance. Originating in PSM literature, factors influencing sourcing team performance are categorised into three: top management support, organisational structures, and those related to team members. In this paper, the concept of...

  19. Flocculation Dynamics of cohesive sediment

    OpenAIRE

    Maggi, F.

    2005-01-01

    Cohesive sediment suspended in natural waters is subject not only to transport and deposition processes but also to reactions of flocculation, \\textit{i.e.} aggregation of fine particles, and breakup of aggregates. Although aggregation and breakup occur at small and very small length scales compared to transport and deposition, flocculation can effectively have an impact on the large scale as well. Some phenomena that are correlated to (or find roots in) flocculation reactions are, for instan...

  20. Regions and the Territorial Cohesion

    OpenAIRE

    Ioan Ianos; Irina Saghin; Gabriel Pascariu

    2013-01-01

    Territorial cohesion is an important target of European Union, constantly promoted by its institutions and their representatives. In the context of the Europe 2020 strategy, one of the most important support documents, the region represents a very important issue, being considered to be the key to its successfulness. The region is seen as a support for the smart growth and all the operational policy concepts try to make use of the spatial potential, by taking better account of the territorial...

  1. Cohesiveness, Productivity, and Wage Dispersion

    OpenAIRE

    Levine, David

    1989-01-01

    When work groups support the goals of the firm, firms will want to narrow wage dispersion in order to increase group cohesiveness and productivity. This narrowing of wage differentials has several implications: (1) Firms will pay wages that vary less than marginal productivity; (2) Firms that must pay the high end of their wage distribution a particularly high wage will pay all workers particularly high wages; (3) The market ignores the rent that egalitarian wages provide to low-wage workers,...

  2. The Impact of Cooperative Video Games on Team Cohesion

    Science.gov (United States)

    Anderson, Greg

    2010-01-01

    In today's economy, productivity and efficiency require collaboration between employees. In order to improve collaboration the factors affecting teamwork must be examined to identify where changes can be made in order to increase performance. One factor contributing to teamwork is team cohesion and represents a process whereby members are joined…

  3. Modeling Asteroid Spin-up with Cohesion

    Science.gov (United States)

    Walsh, Kevin J.; Richardson, D. C.; Michel, P.

    2008-09-01

    Recent work has shown that the gradual spin-up of cohesionless gravitational aggregates produces a wide range of outcomes depending on the specific configuration of the body, such as particle size distribution. One important outcome is the creation of binary asteroids, which requires bodies that can maintain spherical/oblate shapes as the body is spun to rapid rotation (Walsh et al., 2008, Nature, 454, 188-191). Our recent work includes a similar model which also models cohesion within the gravitational aggregate by way of a spring-like restoring force between neighboring particles that vanishes under high strain. We will present early results of gradual spin-up tests on gravitational aggregates covering a large range of starting conditions including the initial body shape and size, as well as varying configurations for the cohesion properties. These results will be compared to previous spin-up work as well as analytical theory. KJW and PM had the support of the French Programme National de Planétologie and the ACT Team of ESA and Ariadna Study 07/4111"Asteroid Rotational Fragmentation". KJW is also supported by the Henri Poincaré fellowship at the Observatoire de la Côte d'Azur, Nice, France, and Rotary International -- District 1730. DCR acknowledges support from the National Science Foundation under grant AST0708110 and the National Aeronautics and Space Administration under Grant No. NNX08AM39G.

  4. Intact Cohesion, Anaphase, and Chromosome Segregation in Human Cells Harboring Tumor-Derived Mutations in STAG2.

    Directory of Open Access Journals (Sweden)

    Jung-Sik Kim

    2016-02-01

    Full Text Available Somatic mutations of the cohesin complex subunit STAG2 are present in diverse tumor types. We and others have shown that STAG2 inactivation can lead to loss of sister chromatid cohesion and alterations in chromosome copy number in experimental systems. However, studies of naturally occurring human tumors have demonstrated little, if any, correlation between STAG2 mutational status and aneuploidy, and have further shown that STAG2-deficient tumors are often euploid. In an effort to provide insight into these discrepancies, here we analyze the effect of tumor-derived STAG2 mutations on the protein composition of cohesin and the expected mitotic phenotypes of STAG2 mutation. We find that many mutant STAG2 proteins retain their ability to interact with cohesin; however, the presence of mutant STAG2 resulted in a reduction in the ability of regulatory subunits WAPL, PDS5A, and PDS5B to interact with the core cohesin ring. Using AAV-mediated gene targeting, we then introduced nine tumor-derived mutations into the endogenous allele of STAG2 in cultured human cells. While all nonsense mutations led to defects in sister chromatid cohesion and a subset induced anaphase defects, missense mutations behaved like wild-type in these assays. Furthermore, only one of nine tumor-derived mutations tested induced overt alterations in chromosome counts. These data indicate that not all tumor-derived STAG2 mutations confer defects in cohesion, chromosome segregation, and ploidy, suggesting that there are likely to be other functional effects of STAG2 inactivation in human cancer cells that are relevant to cancer pathogenesis.

  5. Interchromosomal distribution of gamma ray-induced chromatid aberrations in Chinese hamster ovary cells

    International Nuclear Information System (INIS)

    Inter chromosomal distributions of breakpoints from chromatid-type aberrations induced by gamma rays in Chinese hamster ovary cells were analyzed. In most chromosomes the distribution was as expected from chromosome lengths for simple breaks or the respective relative corrected length in case of exchanges. There were deviations from expectation in a few chromosomes for chromatid breaks, interchanges, intra-arm intra changes and inter-arm intra changes. Especially interesting are the results concerning chromosomes 2 and 8, which were more often involved in exchanges than expected. An 'exchange phenotype' for these chromosomes is proposed and possible explanations for the nonrandom distribution of chromosome breakpoints are presented. (author)

  6. Forms of cohesion in confinement institutions

    OpenAIRE

    Ekaterina D. Slobodenyuk; Evgeniya D. Volkova

    2015-01-01

    Objective to identify the diversity of cohesion forms in confinement institutions. Methods qualitative analyses based on indepth semistructured interviews. Results the study included adaptation of Western methodologies of the cohesion phenomenon analysis to the Russian reality and operationalization of the moral bases of group cohesion. This served as the bases for designing a guide for indepth semistructured interviews 10 interviews were conducted with people recently relea...

  7. Sociodemographic Disparities in Czech Cohesion Regions

    OpenAIRE

    Šotkovský, Ivan

    2011-01-01

    The article is deal with the sociodemographic differences between Czech cohesion regions for the last teenty years and more. There are drew up the basic Czech population and spatial regions differencess in the preface. The spatial hierarchy of the cohesion regions is completed about its eight spatial units. There are those cohesion regions (NUTS 2) in the Czech Republic: Central Bohemia (CBM), Central Moravia (CMR), Moravia Silesia (MS), Northeast (NE), Northwest (NW), Prague (PRG), Southeast...

  8. Automated Behavior and Cohesion Assessment Tools Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An important consideration of long duration space flight operations is interpersonal dynamics that effect crew cohesion and performance. Flight surgeons have stated...

  9. Frequencies of chromosomal aberrations and sister chromatid exchanges in the benthic worm Neanthes arenaceodentata exposed to ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, F.L.; Rice, D.W. Jr., Moore, D.H.

    1984-07-01

    Traditional bioassays are unsuitable for assessing sublethal effects from ocean disposal of low-level radioactive waste because mortality and phenotypic responses are not anticipated. We compared the usefulness of chromosomal aberration and sister chromatid exchange (SCE) induction as measures of low-level radiation effects in a sediment-dwelling marine worm, Neanthes arenaceodentata. The SCEs, in contrast to chromosomal aberrations, do not alter the overall chromosome morphology and in mammalian cells appear to be a more sensitive indicator of DNA alterations caused by environmental mutagens. Newly hatched larvae were exposed to two radiation-exposure regimes of either x rays at a high dose rate of 0.7 Gy (70 rad)/min for as long as 5.5 min or to /sup 60/Co gamma rays at a low dose rate of from 4.8 x 10/sup -5/ to 1.2 x 10/sup -1/ Gy (0.0048 to 12 rad)/h for 24 h. After irradiation, the larvae were exposed to 3 x 10/sup -5/M bromodeoxyuridine (BrdUrd) for 28 h (x-ray-irradiated larvae) or for 54 h (/sup 60/Co-irradiated larvae). Larval cells were examined for the proportion of cells in first, second, and third or greater division. Frequencies of chromosomal aberrations and SCEs were determined in first and second division cells, respectively. Results from x-ray irradiation indicated that dose-related increases occur in chromosome and chromatid deletions, but a dose of equal or greater 2 Gy (equal to or greater than 200 rad) was required to observe a significant increase. Worm larvae receiving /sup 60/Co irradiation showed elevated SCE frequencies with a significant increase of 0.6 Gy (60 rad). We suggest that both SCEs and chromosomal aberrations may be useful for measuring effects on genetic material induced by radiation. 56 references, 7 figures, 9 tables.

  10. Frequencies of chromosomal aberrations and sister chromatid exchanges in the benthic worm Neanthes arenaceodentata exposed to ionizing radiation

    International Nuclear Information System (INIS)

    Traditional bioassays are unsuitable for assessing sublethal effects from ocean disposal of low-level radioactive waste because mortality and phenotypic responses are not anticipated. We compared the usefulness of chromosomal aberration and sister chromatid exchange (SCE) induction as measures of low-level radiation effects in a sediment-dwelling marine worm, Neanthes arenaceodentata. The SCEs, in contrast to chromosomal aberrations, do not alter the overall chromosome morphology and in mammalian cells appear to be a more sensitive indicator of DNA alterations caused by environmental mutagens. Newly hatched larvae were exposed to two radiation-exposure regimes of either x rays at a high dose rate of 0.7 Gy (70 rad)/min for as long as 5.5 min or to 60Co gamma rays at a low dose rate of from 4.8 x 10-5 to 1.2 x 10-1 Gy (0.0048 to 12 rad)/h for 24 h. After irradiation, the larvae were exposed to 3 x 10-5M bromodeoxyuridine (BrdUrd) for 28 h (x-ray-irradiated larvae) or for 54 h (60Co-irradiated larvae). Larval cells were examined for the proportion of cells in first, second, and third or greater division. Frequencies of chromosomal aberrations and SCEs were determined in first and second division cells, respectively. Results from x-ray irradiation indicated that dose-related increases occur in chromosome and chromatid deletions, but a dose of equal or greater 2 Gy (equal to or greater than 200 rad) was required to observe a significant increase. Worm larvae receiving 60Co irradiation showed elevated SCE frequencies with a significant increase of 0.6 Gy (60 rad). We suggest that both SCEs and chromosomal aberrations may be useful for measuring effects on genetic material induced by radiation. 56 references, 7 figures, 9 tables

  11. Regions and the Territorial Cohesion

    Directory of Open Access Journals (Sweden)

    Ioan Ianos

    2013-08-01

    Full Text Available Territorial cohesion is an important target of European Union, constantly promoted by its institutions and their representatives. In the context of the Europe 2020 strategy, one of the most important support documents, the region represents a very important issue, being considered to be the key to its successfulness. The region is seen as a support for the smart growth and all the operational policy concepts try to make use of the spatial potential, by taking better account of the territorial specificities. Two main questions play attention: the need to transform the present-day developmental regions into administrative ones is a priority? What kind of regionalization it must to be promoted? Correlating these issues with already defined territorial cohesion, the administrative region is a real tool for the future territorial development. The experience of the last 14 years asks urgently the building of a new territorial administrative reform, giving competences to regions. For instant, each development region is a construction resulted from a free association of the counties. Their role in the regional development is much reduced one, because their regional councils are not elected; decisions taken at this level are consultative for the social, economical, cultural or political actors.

  12. Comparison of genome stability in two pig breeds by using the sister chromatid exchange (SCE test

    Directory of Open Access Journals (Sweden)

    V. Barbieri

    2010-01-01

    Full Text Available The sister chromatid exchange (SCE test has been used to detect genome stability in humans (Chaganti, 1974 and the main livestock species (Ciotola et al., 2004; Di Meo et al., 2000; Di Berardino et al., 1979, and to discover DNA damage caused by a variety of natural and artificial chemical compounds (Iannuzzi et al., 1990.

  13. RecA stimulates sister chromatid exchange and the fidelity of double-strand break repair, but not gene targeting, in plants transformed by Agrobacterium

    OpenAIRE

    Reiss, Bernd; Schubert, Ingo; Köpchen, Kerstin; Wendeler, Edelgard; Schell, Jeff; Puchta, Holger

    2000-01-01

    Expression of the bacterial RecA protein in plants stimulates homologous recombination in tobacco. Here we show that RecA plays a direct role in DNA strand exchange in vivo. The number of sister chromatid exchanges (SCEs) was increased 2.4-fold over wild type in transgenic tobacco plants expressing a nuclear-targeted RecA (nt-RecA) protein and could not be increased further by DNA damage, which caused a doubling of the baseline SCE frequency in wild-type plants. Although gene targeting requir...

  14. Investigations into the molecular mechanism of chromatid breakage in the G2-phase of mammalian cells

    International Nuclear Information System (INIS)

    Chromatid breakage following irradiation of cells in the G2-phase of the cell cycle results from the induction of DNA double-strand breaks (dsb). The conversion of dsb into chromatid breaks (cb) has a genetic basis, seemingly different from that of dsb rejoining. The variation in extent of this conversion is exemplified by the stiking variation in frequency of cb in irradiated cycling T-lymphocytes between different normal individuals. Elevated cb frequency in lymphocytes of around 40% of breast cancer patients and their first-degree relatives suggests the presence of mutations in low penetrance cancer predisposing genes that also affect conversion of dsb to cb. Investigation of the mechanism of chromatid radiosensitivity using genetically engineered rodent cell lines containing unique dsb break sites indicate that a single isolated dsb is sufficient to cause a cb. The single-event nature of chromatid breakage is confirmed by the fact that cb are induced as a linear function of radiation dose. Moreover, we have recently shown that ultrasoft carbon-K X-rays also induce chromatid breakage. In this case the energy of the secondary electrons produced by carbon-K X-rays is too low to span more than one DNA double helix, thus further supporting our conclusion that a single dsb is responsible for the formation of a cb. Chromatid breakage is thought to involve a rearrangement between DNA strands at the crossover points of chromatin loop(s) triggered by the presence of a dsb within the loop structure. The occasional observation of 'looped-out' sections of chromatin at cb sites supports this hypothesis. The occurrence of 'colour-switches' between FPG stained chromatids at a proportion of break sites (e.g. about 16% in CHO cells) shows that a significant proportion of cb definitely result from chromatin rearrangements. Measurements of altered colour-switch ratio (csr) in mutant rodent and human cells (irs1 and AT cells respectively) also indicate a genetic basis for the

  15. "-ing" Project: Encouraging Cohesion in Small Groups

    Science.gov (United States)

    McBride, M. Chad

    2006-01-01

    Group cohesiveness is a topic addressed in most small group communication texts and courses and is often defined as the degree of attraction members feel towards one another, the degree of loyalty within a group, or the "groupness" felt among members. Further, groups which are cohesive tend to be happier and more productive. When working on…

  16. Pathways from jobs to social cohesion

    OpenAIRE

    Wietzke, Frank-Borge

    2014-01-01

    There is growing recognition that access to good jobs is an important driver of social cohesion. While economic dimensions of labor market outcomes are relatively well documented, evidence on the link between social cohesion and jobs is still surprisingly scarce. This paper, based on an earlier background report for the WDR 2013, presents empirical evidence for pathways between labor marke...

  17. Why are Rich Countries more Politically Cohesive?

    DEFF Research Database (Denmark)

    Dalgaard, Carl-Johan Lars; Olsson, Ola

    other groups in society. If the gains from specialization become sufficiently large, however, a market economy will emerge. From being essentially non-cohesive under self-sufficiency, the political decision making process becomes cohesive in the market economy, as the welfare of individuals will be...

  18. Low density fragile states in cohesive powders

    OpenAIRE

    Umbanhowar, Paul B.; Goldman, Daniel I.

    2005-01-01

    We discuss the difference between cohesive and non-cohesive granular media in the context of a recent report of "dry quicksand." Weak low density states with properties like dry quicksand are readily formed in common household powders. In contrast, such states cannot be formed in cohesionless granular media such as ordinary sand.

  19. Transfer and Cohesion in Interdisciplinary Education

    Directory of Open Access Journals (Sweden)

    Søren Harnow Klausen

    2014-06-01

    Full Text Available One of the great challenges of interdisciplinary education is to create sufficient cohesion between disciplines. It is suggested that cohesion depends on the transfer of knowledge (in a broad sense, which includes skill and competences among the disciplines involved. Some of the most characteristic types of such transfer are identified and analyzed: Transfer of factual knowledge, theories, methods, models, skills, modes of collaboration and organization, meta-competences, disciplinary self-consciousness, problem selection, framework construction and motivation. Though some of these types of transfer may have a greater or smaller potential for creating cohesion, different kinds of cohesion may serve different interests, and there is no reason to assume that e.g. joint problem solving or theoretical integration should be more conducive to cohesion than e.g. contributions to motivation or disciplinary self-consciousness.

  20. Pension Insurance Cohesive Testing System

    Directory of Open Access Journals (Sweden)

    Askarbek Arzybaev

    2015-01-01

    Full Text Available Many public pension systems worldwide are experiencing difficult economic period as its economy is in the period of financial crisis which affected to the social budget sustainability.Population aging and last decade economic circumstances are the factors the pension systems should overcome for maintaining either appropriate level of benefit amount for decent life in the developed countries or minimum subsistence allowances in developing and poor countries. The only prescription how to keep the pension system resistible is its periodical renovation by testing the system on (i soundness and effectiveness within national financial and economic system, (ii appropriateness of its organization and administration, (iii compliance of parameters with international standards. The article presents Cohesive Testing System – new method of national pension systems testing and indexing based on international standards of pension security and new CTS indices of the researched set of pension systems.

  1. The Effects Of Physical And Biological Cohesion On Bedforms

    Science.gov (United States)

    Parsons, D. R.; Schindler, R.; Baas, J.; Hope, J. A.; Malarkey, J.; Paterson, D. M.; Peakall, J.; Manning, A. J.; Ye, L.; Aspden, R.; Alan, D.; Bass, S. J.

    2014-12-01

    Most coastal sediments consist of complex mixtures of cohesionless sands, physically-cohesive clays and extra cellular polymeric substances (EPS) that impart biological cohesion. Yet, our ability to predict bedform dimensions in these substrates is reliant on predictions based exclusively on cohesionless sand. We present findings from the COHBED project - which explicitly examines how bedform dynamics are modified by natural cohesion. Our experimental results show that for ripples, height and length are inversely proportional to initial clay content and bedforms take longer to appear, with no ripples when clay content exceeds 18%. When clay is replaced by EPS the development time and time of first appearance of ripples both increase by two orders of magnitude, with no bedforms above 0.125% EPS. For dunes, height and length are also inversely proportional to initial substrate clay content, resulting in a transition from dunes to ripples normally associated with velocity decreases. Addition of low EPS concentrations into the substrate results in yet smaller bedforms at the same clay contents and at high EPS concentrations, biological cohesion supersedes all electrostatic bonding, and bedform size is no longer related to mud content. The contrast in physical and biological cohesion effects on bedform development result from the disparity between inter-particle electrostatic bonding of clay particles and EPS grain coating and strands that physically link sediments together, which effects winnowing rates as bedforms evolve. These findings have wide ranging implications for bedform predictions in both modern and ancient environments. Coupling of biological and morphological processes not only requires an understanding of how bedform dimensions influence biota and habitat, but also how benthic species can modify bedform dimensions. Consideration of both aspects provides a means in which fluid dynamics, sediment transport and ecosystem energetics can be linked to yield

  2. INDUCTION, ACCUMULATION, AND PERSISTENCE OF SISTER CHROMATID EXCHANGES IN WOMEN WITH BREAST CANCER RECEIVING CYCLOPHOSPHAMIDE, ANDRIAMYCIN, AND 5-FLUOROACIL CHEMOTHERAPY

    Science.gov (United States)

    The induction, stimulation, and persistence of sister chromatid exchanges (SCE's) and high SCE frequency cells (HFC's) was measured in peripheral lymphocytes of women with breast cancer before chemotherapy and on multiple occasions during and after therapy. Chemotherapy consisted...

  3. Shugoshin1 May Play Important Roles in Separation of Homologous Chromosomes and Sister Chromatids during Mouse Oocyte Meiosis

    OpenAIRE

    Shen Yin; Jun-Shu Ai; Li-Hong Shi; Liang Wei; Ju Yuan; Ying-Chun Ouyang; Yi Hou; Da-Yuan Chen; Heide Schatten; Qing-Yuan Sun

    2008-01-01

    BACKGROUND: Homologous chromosomes separate in meiosis I and sister chromatids separate in meiosis II, generating haploid gametes. To address the question why sister chromatids do not separate in meiosis I, we explored the roles of Shogoshin1 (Sgo1) in chromosome separation during oocyte meiosis. METHODOLOGY/PRINCIPAL FINDINGS: Sgo1 function was evaluated by exogenous overexpression to enhance its roles and RNAi to suppress its roles during two meioses of mouse oocytes. Immunocytochemistry an...

  4. Design of Normal Concrete Mixtures Using Workability-Dispersion-Cohesion Method

    OpenAIRE

    Hisham Qasrawi

    2016-01-01

    The workability-dispersion-cohesion method is a new proposed method for the design of normal concrete mixes. The method uses special coefficients called workability-dispersion and workability-cohesion factors. These coefficients relate workability to mobility and stability of the concrete mix. The coefficients are obtained from special charts depending on mix requirements and aggregate properties. The method is practical because it covers various types of aggregates that may not be within sta...

  5. Frequency of sister chromatid exchange and chromosomal aberrations in asbestos cement workers.

    OpenAIRE

    Fatma, N; Jain, A. K.; Rahman, Q

    1991-01-01

    Exposure to asbestos minerals has been associated with a wide variety of adverse health effects including lung cancer, pleural mesothelioma, and cancer of other organs. It was shown previously that asbestos samples collected from a local asbestos factory enhanced sister chromatid exchanges (SCEs) and chromosomal aberrations in vitro using human lymphocytes. In the present study, 22 workers from the same factory and 12 controls were further investigated. Controls were matched for age, sex, and...

  6. "Sister Chromatid Exchanges and Micronuclei in Lymphocyte of Nurses Handling Antineoplastic Drugs"

    OpenAIRE

    Ansari-Lari, M; M.Saadat; Shahryari, M.; DD Farhud

    2001-01-01

    Individuals handling antineoplastic drugs or their wastes may absorb these potent genotoxic agents. The effects of handling antineoplastic drugs were examined in a group of 24 nurses working in the hematology and oncology departments of two different university hospitals in Shiraz (Iran) and in a group of 18 unexposed nurses as control group. The cytogenetic repercussions of exposure were assessed by examining sister chromatid exchanges (SCEs) and micronuclei (Mn) in circulating lymphocytes. ...

  7. Sister chromatid exchange analysis in lymphocytes of workers exposed to hexavalent chromium.

    OpenAIRE

    Nagaya, T.; Ishikawa, N.; Hata, H.

    1989-01-01

    To investigate the usefulness of sister chromatid exchange (SCE) analysis in lymphocytes as an indicator for mutagenic effects after in vivo exposure to hexavalent chromium (Cr), SCE frequency was analysed in lymphocytes of 44 Cr platers occupationally exposed to hexavalent Cr and 47 controls. Although urinary Cr analysis confirmed that the Cr platers were exposed to Cr, no effects of the exposure on SCE frequency were found. Smokers, both Cr platers and controls, had a significantly higher S...

  8. An increase in telomere sister chromatid exchange in murine embryonic stem cells possessing critically shortened telomeres

    OpenAIRE

    Wang, Yisong; Erdmann, Natalie; Giannone, Richard J.; Wu, Jun; Gomez, Marla; Liu, Yie

    2005-01-01

    Telomerase deficiency leads to a progressive loss of telomeric DNA that eventually triggers cell apoptosis in human primary cells during prolonged growth in culture. Rare survivors can maintain telomere length through either activation of telomerase or recombination-based telomere lengthening, and thus proliferate indefinitely. We have explored the possibility that telomeres may be maintained through telomere sister chromatid exchange (T-SCE) in murine telomere reverse transcriptase-deficient...

  9. A study of sister chromatid exchange in patients with dental amalgam restorations

    OpenAIRE

    E Lakshmi Priya; K Ranganathan; Uma Devi K Rao; Elizabeth Joshua; Deepu George Mathew; Kavitha Wilson

    2014-01-01

    Study Background: Dental amalgam is still widely used as a restorative material in developing countries due to its low cost and ease of manipulation. The health risks associated with the components of this restorative material has always been a matter of concern. Our study was designed to address this question regarding dental amalgam. Objective: To study sister chromatid exchange (SCE) as an indicator of systemic genotoxicity, due to the exposure from the components of amalgam restoratio...

  10. Radiation-induced chromosome aberrations and sister chromatid exchanges in lymphocytes from patients with tuberous sclerosis

    International Nuclear Information System (INIS)

    Lymphocytes from four patients with tuberous sclerosis (TS) and four normal controls were studied for sister chromatid exchanges (SCEs) and chromosome aberrations in gamma-ray irradiated cultures. There was no significant difference between SCE frequencies of TS lymphocytes and those of control lymphocytes at all doses examined (1, 2, and 4 Gy). However, chromosome aberrations in TS lymphocytes were significantly higher than those in the normal controls at the highest dose (4 Gy) (p < 0.05). (author)

  11. Sister Chromatid Exchange Frequency in Lymphocytes Cultured from Cotton Gin Workers

    OpenAIRE

    ATMACA, Münevver; BAĞCI, Hüseyin; AÇIKBAŞ, İbrahim; GÜMÜŞ, Dilihan; DÜZCAN, Füsun

    2004-01-01

    Genetic biomonitoring of human populations exposed to potential mutagens/carcinogens can be performed using different genetic markers. Sister chromatid exchange (SCE) is one of the most extensively used markers of the early biological effects of DNA damaging agents. In order to assess the genotoxicity associated with exposure to cotton dust, we determined SCE frequency in peripheral blood lymphocytes cultured from 20 cotton gin workers and 20 controls. Student’s-t test indicated an ...

  12. Challenging the wall of fast rotating asteroids - constraining internal cohesive strength for MBAs and NEAs

    Science.gov (United States)

    Polishook, David; Moskovitz, Nicholas; Binzel, Richard P.; DeMeo, Francesca E.; Aharonson, Oded; Thomas, Cristina; Lockhart, Matthew; Thirouin, Audrey; Mommert, Michael; Trilling, David; Burt, Brian

    2015-11-01

    We report an observation of a 2 km size main belt asteroid (MBA), (60716) 2000 GD65, with a lightcurve indicating a rotation period of 1.9529±0.0002 hours, i.e. challenging the ‘rubble pile spin barrier’. This adds to a handful of MBAs, recently observed by the Palomar Transient Factory (PTF) survey (Chang et al. 2014, 2015), with diameters between 0.5-1.5 km and lightcurves indicating rotation periods of 1.2-1.9 hours. These asteroids are relatively large compared to the population of small near-Earth asteroids (NEAs; Dteam).We apply the Holsapple (2007) model to these two distinct populations in order to constrain the cohesion within these objects and to search for monolithic asteroids. We use the lightcurve’s amplitude as indication of the triaxial shape ratio a/b, and assume b/c=1 (i.e. a>b=c). While the density is a free parameter, the given cohesion is the average of values for density ranges between 1.5 to 2.5 gr cm^-3, which are measured density values for asteroids (Carry 2012).We find that the fast rotating MBAs must have internal cohesive strength of at least ~25 to ~250 Pa in order to prevent disruption against centrifugal acceleration. Similar cohesion values have been found within lunar soils (100-1000 Pa; Mitchell et al. 1974). However, since only a few MBAs rotate so quickly, such internal cohesive strength might be rare within the population of km-size MBAs. Among NEAs, about 25% have minimal constrained cohesion values similar to those found for the fast rotating MBAs. Approximately 65% have no need for substantial cohesion values >25 Pa. Only ~10% of NEAs must have substantial internal cohesion of over 1000 Pa to prevent disruption, however none of them are rotating fast enough to require a fully monolithic body, i.e. cohesion >10 kPa.

  13. Multiple Rad5 activities mediate sister chromatid recombination to bypass DNA damage at stalled replication forks.

    Science.gov (United States)

    Minca, Eugen C; Kowalski, David

    2010-06-11

    DNA damage that blocks replication is bypassed in order to complete chromosome duplication and preserve cell viability and genome stability. Rad5, a PCNA polyubiquitin ligase and DNA-dependent ATPase in yeast, is orthologous to putative tumor suppressors and controls error-free damage bypass by an unknown mechanism. To identify the mechanism in vivo, we investigated the roles of Rad5 and analyzed the DNA structures that form during damage bypass at site-specific stalled forks present at replication origins. Rad5 mediated the formation of recombination-dependent, X-shaped DNA structures containing Holliday junctions between sister chromatids. Mutants lacking these damage-induced chromatid junctions were defective in resolving stalled forks, restarting replication, and completing chromosome duplication. Rad5 polyubiquitin ligase and ATPase domains both contributed to replication fork recombination. Our results indicate that multiple activities of Rad5 function coordinately with homologous recombination factors to enable replication template switch events that join sister chromatids at stalled forks and bypass DNA damage. PMID:20541998

  14. IMISCOE: Immigration, Social Cohesion and Social Innovation

    Czech Academy of Sciences Publication Activity Database

    Beranská, Veronika

    2014-01-01

    Roč. 101, č. 4 (2014), s. 488-489. ISSN 0009-0794 Institutional support: RVO:68378076 Keywords : migration * integration * social diversification * social cohesion Subject RIV: AC - Archeology, Anthropology, Ethnology Impact factor: 0.094, year: 2012

  15. Modelling cohesive, frictional and viscoplastic materials

    Science.gov (United States)

    Alehossein, Habib; Qin, Zongyi

    2016-06-01

    Most materials in mining and civil engineering construction are not only viscoplastic, but also cohesive frictional. Fresh concrete, fly ash and mining slurries are all granular-frictional-visco-plastic fluids, although solid concrete is normally considered as a cohesive frictional material. Presented here is both a formulation of the pipe and disc flow rates as a function of pressure and pressure gradient and the CFD application to fresh concrete flow in L-Box tests.

  16. Mixed Mode cohesive law with interface dilatation

    DEFF Research Database (Denmark)

    Sørensen, Bent F.; Goutianos, Stergios

    2014-01-01

    shear stresses opposing the crack face displacements. A phenomenological Mixed Mode cohesive zone law, derived from a potential function, is developed to describe the above mentioned fracture behaviour under monotonic opening. The interface dilatation introduces two new lengths. The cohesive law is...... implemented in the commercial finite element program Abaqus. The model is validated and tested against experimental results under various mode mixities. © 2013 Elsevier Ltd. All rights reserved....

  17. Understanding changes in social cohesion in Bolivia

    OpenAIRE

    Werner L. Hernani-Limarino

    2010-01-01

    This paper attempts to measure and explain the changes in “social cohesion” that took place in Bolivia during the first term of presidency of Evo Morales Ayma - Bolivia’s first indigenous president. Following Maxwell (2006), we define social cohesion as a distribution of beliefs, values and modes of thinking that make people feel they are members of the same community, engaged in common enterprises, and facing shared challenges. Accordingly, we measure the lack of social cohesion as the obser...

  18. Social norms, social cohesion, and corporate governance

    OpenAIRE

    Boytsun, Andriy; DELOOF, Marc; MATTHYSSENS, Paul

    2010-01-01

    Abstract Manuscript Type: Empirical Research Question/Issue: We study the relationship between informal rules (represented by social norms and social cohesion in a community) and corporate governance. A community is a large social unit characterized by a distinct set of informal rules. Specifically, three hypotheses are tested: (1) Communities with stronger social norms will have more open firm-level corporate governance, (2) More socially cohesive communities will have more op...

  19. In Vitro genotoxic and antigenotoxic studies of Thai Noni fruit juice by chromosomal aberration and sister chromatid exchange assays in human lymphocytes

    Directory of Open Access Journals (Sweden)

    Treetip Ratanavalachai

    2008-09-01

    Full Text Available The genotoxic and antigenotoxic effects of Noni fruit juice produced in Thailand have been studied in human lymphocytes for chromosome aberration assay and sister chromatid exchange (SCE assay in vitro. Treatment of Noni fruit juice(3.1-50 mg/ml alone for 3 h did not significantly induce chromosomal aberration or SCE (p<0.05. Noni fruit juice at 6.2 mg/ml is the optimum dose for cell survival and cell replication as demonstrated by the highest value of mitotic index and proliferation index (P.I.. Interestingly, pretreatment of Noni fruit juice at the same concentration of 6.2 mg/ml for 2 hfollowed by mitomycin C treatment at 3 μg/ml for 2 h significantly reduced SCE level induced by mitomycin C (p<0.05. However, these treatments did not show significant decrease in chromatid-type aberrations. Our data indicate that Thai Noni fruit juice is not genotoxic against human lymphocytes in vitro. In addition, pretreatment of Noni fruit juice at 6.2 mg/ml demonstrated no anticlastogenic effect while had some antigenotoxic effects as demonstrated by significant decrease in the SCE level induced by mitomycin C (p<0.05. Therefore, the optimum dose of Noni fruit juice used as a traditional medicine is required and needs to be studied further for the benefit of human health.

  20. Processing, localization, and requirement of human separase for normal anaphase progression

    OpenAIRE

    Chestukhin, Anton; Pfeffer, Christian; Milligan, Scott; DeCaprio, James A.; Pellman, David

    2003-01-01

    In all eukaryotes, anaphase is triggered by the activation of a protease called separase. Once activated, separase cleaves a subunit of cohesin, a complex that links replicated chromatids before anaphase. Separase and cohesin are conserved from yeasts to humans. Although the machinery for dissolving sister cohesion is conserved, the regulation of this process appears to be more complex in higher eukaryotes than in yeast. Here we report the cloning of full-length human separase cDNA and the ch...

  1. An information retrieval based approach for measuring service conceptual cohesion

    OpenAIRE

    Kazemi, Ali; Rostampour, Ali; Zamir, Amin; Jamshidi, Pooyan; Haghighi, Hassan; Shams, Fereideon

    2011-01-01

    non-peer-reviewed High cohesion as a desirable principle in software design has an incredible impact on software reuse, maintenance and support. In service-oriented architecture (SOA), the focus of services on single business functionality is defined as conceptual cohesion. Current metrics for measuring service cohesion reflect mostly the structural aspect of cohesion and therefore cannot be utilized to measure conceptual cohesion of services. Latent Semantic Indexing (LSI), on the othe...

  2. A Study on the Effect of Cohesive Laws on Finite Element Analysis of Crack Propagation Using Cohesive Elements

    International Nuclear Information System (INIS)

    In this paper, the effect of cohesive laws on the finite element analysis of crack propagation using cohesive elements is investigated through three-point bending and double cantilever beam problems. The cohesive elements are implemented into ABAQUS/Standard user subroutines(UEL), and the shape of cohesive law is varied by changing parameters in polynomial functions of cohesive traction-separation relations. In particular, crack propagation behaviors are studied by comparing load-displacement curves of the analysis models which have different shapes of cohesive laws with the same values of fracture energy and cohesive strength. Furthermore, the influence of the element size on crack propagation is discussed in this study

  3. Cohesion and Hierarchy in Physically Abusive Families

    Directory of Open Access Journals (Sweden)

    Clarissa De Antoni

    2009-06-01

    Full Text Available This paper investigates cohesion (emotional bonding and hierarchy (powerstructure in families with abuse against their children. Twenty low-incomefamilies participated. Father, mother and child’s perspective of family relations(cohesion and hierarchy were evaluated by the Family System Test(FAST. The relationship between father-child, mother-child, couple, andamong siblings were evaluated at typical and conflictive situations. Resultsshow a significance regarding to cohesion in typical and conflictive situationfor father-child and mother-child dyads in all perspectives (by father, mother,and child. There is no significant differences regarding to hierarchy. Theseresults suggest that the families see the intrafamilial violence as a constant,since they cannot differentiate between both situations.

  4. "Sister Chromatid Exchanges and Micronuclei in Lymphocyte of Nurses Handling Antineoplastic Drugs"

    Directory of Open Access Journals (Sweden)

    M Ansari-Lari

    2001-07-01

    Full Text Available Individuals handling antineoplastic drugs or their wastes may absorb these potent genotoxic agents. The effects of handling antineoplastic drugs were examined in a group of 24 nurses working in the hematology and oncology departments of two different university hospitals in Shiraz (Iran and in a group of 18 unexposed nurses as control group. The cytogenetic repercussions of exposure were assessed by examining sister chromatid exchanges (SCEs and micronuclei (Mn in circulating lymphocytes. A significant increased frequencies of SCE and Mn is observed in circulating lymphocytes. A significant increased frequencies of SCE and Mn is observed in nurses in daily contact with antineoplastic drugs as compared to control group.

  5. Photoreactivation of ultraviolet light-induced sister chromatid exchanges in potorous cells

    International Nuclear Information System (INIS)

    Exposure to visible light after UV-irradiation showed a remarkable effect on UV-induced sister chromatid exchanges (SCEs). After 6-h exposure to visible light (3 x 105 J/m2), two-thirds of the UV-induced SCEs were prevented, confirming Kato's findings. (Nature 249, 552-3, 1974) Exposure to visible light before UV irradiation had no effect. This effect of visible light on UV-induced CSEs was temperature dependent, suggesting the presence of enzymatic photoreactivation. (author)

  6. Evaluation of the persistence in the induction of Sister Chromatid Exchanges (SCE) by alkylating agents

    International Nuclear Information System (INIS)

    The persistence in the induction of sister chromatid exchanges (SCE) by the alkylating agents methyl and ethyl-methanesulfonates (MMS and EMS) was evaluated. For it, to groups of mice its were administered a dose of these agents and later its were analyzed the induced SCE's in two periods: early and late. Both agents caused high increments of SCE in the early period and small in the late one; however, the caused lately by EMS was significantly bigger. This late induction of SCE by EMS possibly is associated with an epigenetic change or with the presence of etiladucts in the phosphodiester bonds of the DNA. (Author)

  7. Chromosome aberrations and sister chromatid exchanges in Swedish paint industry workers

    Energy Technology Data Exchange (ETDEWEB)

    Haglund, U.; Lundberg, I.; Zech, L.

    1980-12-01

    Workers in the Swedish paint industry exposed to a mixture of organic solvents, mainly containing xylene or toluene, were investigated for genotoxic effects. No difference in the frequency of sister chromatid exchanges (SCE), 0.192 and 0.193 per chromosome, respectively, was noted in the peripheral lymphocytes of the exposed group of 17 workers and their matched reference group. No correlation was found between xylene or toluene exposure and SCE frequency nor between total solvent exposure and SCE frequency. The frequency of chromosome aberrations was also investigated for the five most exposed workers and their matched referents, and no difference was found. There was no correlation between SCE and chromosome breaks.

  8. A proposal of a standardised nomenclature for terminal minute sister chromatid exchanges

    Directory of Open Access Journals (Sweden)

    Máximo E. Drets

    2006-01-01

    Full Text Available We described spontaneous minute sister chromatid exchanges (SCE in telomeric regions of human and Chinese hamster ovary (CHO chromosomes more than 10 years ago. These structures, which we called t-SCE, were detected by means of highly precise quantitative microphotometrical scanning and computer graphic image analysis. Recently, several authors using the CO-FISH method also found small SCEs in telomeric regions and called them T-SCE. The use of different terms for designating the same phenomenon should be avoided. We propose ter SCE as a uniform nomenclature for minute telomeric SCEs.

  9. Cohesion in ball lightning and cook plasmas

    International Nuclear Information System (INIS)

    The phenomenon of ball lightning has been observed for a long time, but the nature of these luminous balls has been unknown. It is proposed here that they consist of highly excited Rydberg atoms with large polarizabilities. Thus the cohesion of the balls comes from photon exchange forces (London dispersion forces) rather than electron exchange (chemical) forces. The cohesion in plasmas generated at the back faces of detonating explosives (Cook's plasmas) may have a similar basis. Numerical estimates are given to justify these interpretations

  10. Anisotropy in cohesive, frictional granular media

    International Nuclear Information System (INIS)

    The modelling of cohesive, frictional granular materials with a discrete particle molecular dynamics is reviewed. From the structure of the quasi-static granular solid, the fabric, stress, and stiffness tensors are determined, including both normal and tangential forces. The influence of the material properties on the flow behaviour is also reported, including relations between the microscopic attractive force and the macroscopic cohesion as well as the dependence of the macroscopic friction on the microscopic contact friction coefficient. Related to the dynamics, the anisotropy of both structure and stress are exponentially approaching the maximum

  11. Peer interaction and learning opportunities in cohesive and less cohesive L2 classrooms

    OpenAIRE

    Leslie, Carolyn Elizabeth

    2016-01-01

    The present study investigates peer to peer oral interaction in two task based language teaching classrooms, one of which was a self-declared cohesive group, and the other a self- declared less cohesive group, both at B1 level. It studies how learners talk cohesion into being and considers how this talk leads to learning opportunities in these groups. The study was classroom-based and was carried out over the period of an academic year. Research was conducted in the classrooms and the task...

  12. Influence of irradiation at different stages of mitotic cycle upon production of sister chromatid exchanges in cultured Chinese hamster cells

    International Nuclear Information System (INIS)

    Frequency of sister chromatid exchanges (SCE) and microexchanges in Chinese hamster cells has been studied by means of the method of differential staining of chromatids on irradiation at different stages of the mitotic cycle. It is shown that the irradiation enhances frequency of SCE and microexchanges if it is carried out before the end of DNA replication synthesis. Comparison of frequency depenedence of radiation-induced microexchanges and SCE at different stages of the mitotic cycle results in the conclusion that the microexchanges are none other than small SCE

  13. Influence of irradiation at different stages of mitotic cycle unon production of sister chromatid exchanges in cultured chinese hamster cells

    International Nuclear Information System (INIS)

    Frequency of.sister chromatid exchanges (SCE) and microexchanges in the chinese hamster cells was investigated by means of the method of differential colouring of chromatids on irradiation at different stages of the mitotic cycle. It is shown that the irradiation increases frequency of SCE and microexchanges if it is performed before the end of the replicative DNA synthesis. Comparison of frequency dependence of radiation-induced microexchanges and SCE at different stages of the mitotic cycle permits to conclude that the microexchanges are small SCE

  14. Cultured mouse embryos metabolize benzo[a]pyrene during early gestation: genetic differences detectable by sister chromatid exchange.

    OpenAIRE

    Galloway, S M; Perry, P E; Meneses, J. (Julio); Nebert, D W; Pedersen, R A

    1980-01-01

    Mouse embryos explanted at 7 1/2 or 8 1/2 days of gestation were cultured in medium containing benzo[a]pyrene and supplemented with 5-bromodeoxyuridine to allow detection of sister chromatid exchanges. The murine Ah locus regulates the inducible metabolism of polycyclic hydrocarbons such as benzo[a]pyrene. A high frequency of sister chromatid exchange was induced by benzo[a]pyrene in embryos from three Ah-"responsive" inbred strains (BALB/cDub, C3H/AnfCum, and C57BL/6N); there was little or n...

  15. Group Cohesion in Experiential Growth Groups

    Science.gov (United States)

    Steen, Sam; Vasserman-Stokes, Elaina; Vannatta, Rachel

    2014-01-01

    This article explores the effect of web-based journaling on changes in group cohesion within experiential growth groups. Master's students were divided into 2 groups. Both used a web-based platform to journal after each session; however, only 1 of the groups was able to read each other's journals. Quantitative data collected before and…

  16. Validation of the Child Sport Cohesion Questionnaire

    Science.gov (United States)

    Martin, Luc J.; Carron, Albert V.; Eys, Mark A.; Loughead, Todd

    2013-01-01

    The purpose of the present study was to test the validity evidence of the Child Sport Cohesion Questionnaire (CSCQ). To accomplish this task, convergent, discriminant, and known-group difference validity were examined, along with factorial validity via confirmatory factor analysis (CFA). Child athletes (N = 290, M[subscript age] = 10.73 plus or…

  17. Investigating Team Cohesion in COCOMO II.2000

    Science.gov (United States)

    Snowdeal-Carden, Betty A.

    2013-01-01

    Software engineering is team oriented and intensely complex, relying on human collaboration and creativity more than any other engineering discipline. Poor software estimation is a problem that within the United States costs over a billion dollars per year. Effective measurement of team cohesion is foundationally important to gain accurate…

  18. Team Cohesion Effects on Business Game Performance.

    Science.gov (United States)

    Wolfe, Joseph; Box, Thomas M.

    1988-01-01

    Discussion of teamwork and group decision making focuses on study of undergraduates conducted to identify the variables that affect team cohesion in a business game. A literature review on small groups and business games is presented, hypotheses tested are described, discriminant analyses are explained, and suggestions for further research are…

  19. Toward a Cohesive Theory of Visual Literacy

    Science.gov (United States)

    Avgerinou, Maria D.; Pettersson, Rune

    2011-01-01

    Despite the fact that to date Visual Literacy (VL) scholars have not arrived at a general consensus for a theoretical organization of the VL field, important conceptual investigations have emerged over the past four decades. In this paper we discuss and synthesize those studies. We then present a first attempt toward a cohesive theory of VL. The…

  20. Building Cohesion in Positively Connected Exchange Networks

    Science.gov (United States)

    Schaefer, David R.; Kornienko, Olga

    2009-01-01

    This research investigates the process through which individuals build cohesive relationships in positively connected exchange relations. Positive connections exist any time exchange in one relation must precede exchange in another. Such situations arise through gatekeeping, in generalized exchange contexts, and when resources diffuse across a…

  1. The Corporate Stake in Social Cohesion

    Science.gov (United States)

    Oketch, Moses O.

    2005-01-01

    Corporate Social Responsibility (CSR) is a function that transcends, but includes, making profits, creating jobs, and producing goods and services. The effectiveness with which corporations perform this function determines their contribution (or lack of contribution) to social cohesion. This article therefore presents a discussion of some of the…

  2. Role of Education in Building Social Cohesion

    Science.gov (United States)

    Khan, Zebun Nisa

    2016-01-01

    Social Cohesion is the expression of that tradition of tolerance in all religions and cultures that are the basis of peace and progress. It is foreign to know culture and native to all nations. Tolerance and mercy have always and in all cultures being ideals of Government rules and human behavior. Professional educator often comments on the poor…

  3. Justice and Social Cohesion: Some conservative perspectives

    DEFF Research Database (Denmark)

    Pedersen, Søren Hviid

    2011-01-01

    liberals, on how to accommodate the different demands of various ethnic and religious groups and at the same time sustain a minimum of social cohesion and justice. One voice is missing and that is a conservative perspective. The purpose of this paper is to formulate a modern conservative analysis of this...

  4. On the Relationships between the Cohesive Devices and Their Meanings

    Institute of Scientific and Technical Information of China (English)

    肖肇威

    2008-01-01

    Cohesion is one of the phenomena of the text. It is expressed through the cohesive devices.As part of Functional Grammar,the cohesive devices relate themselves naturally to the meanings,which exist both in the text and in its social context.This paper is to explore the relationship between the cohesive devices and their meanings.These meanings subsume the discourse semantics in the text and the register in the social context.

  5. A cohesive elements based model to describe fracture and cohesive healing in elastomers

    OpenAIRE

    Baldi, A; Grande, A.M.; Bose, R.K.; Airoldi, A.; Garcia Espallargas, S.J.; Di Landro, L.; Van Der Zwaag, S.

    2013-01-01

    Several polymeric systems with intrinsic Self-Healing (SH) capabilities have been reported in literature. Many of them showed healing upon contact across the crack interface. Different parameters such as contact time, temperature, pressure or chemical activity determine the degree of healing obtained. In this work, a numerical simulation of the healing efficiency as a function of the environment is proposed based on the use of cohesive elements in a finite element model. Cohesive elements are...

  6. The Saccharomyces cerevisiae centromere protein Slk19p is required for two successive divisions during meiosis.

    OpenAIRE

    Zeng, X.; Saunders, W S

    2000-01-01

    Meiotic cell division includes two separate and distinct types of chromosome segregation. In the first segregational event the sister chromatids remain attached at the centromere; in the second the chromatids are separated. The factors that control the order of chromosome segregation during meiosis have not yet been identified but are thought to be confined to the centromere region. We showed that the centromere protein Slk19p is required for the proper execution of meiosis in Saccharomyces c...

  7. Facilitating Group Cohesion among Adolescents through Challenge Course Experiences.

    Science.gov (United States)

    Glass, J. Scott; Benshoff, James M.

    2002-01-01

    A study examined the effects of participation in a low-element challenge course on younger adolescents' perceptions of group cohesion. Pre- and post-tests of group cohesion were administered to 167 North Carolina adolescents aged 11-14. Participants perceived an increase in group cohesion after the daylong program, regardless of their age, race,…

  8. Cohesiveness and Performance on an Additive Task: Evidence for Multidimensionality.

    Science.gov (United States)

    Zaccaro, Stephen J.; Lowe, Charles A.

    1988-01-01

    Presents a study designed to contrast the effects of task-based and interpersonal cohesiveness on group performance of students. Concludes that high task cohesion helped group performance, while interpersonal attraction had no apparent effect. Finding that increased interpersonal cohesion improved task commitment, the authors suggest that…

  9. Biomonitoring of genotoxic risk in radar facility workers: comparison of the comet assay with micronucleus assay and chromatid breakage assay

    International Nuclear Information System (INIS)

    Genotoxic risks of occupational exposure in a radar facility were evaluated by using alkaline comet assay, micronucleus assay and chromatid breakage assay on peripheral blood leukocytes in exposed subjects and corresponding controls. Results show that occupational exposure to microwave radiation correlates with an increase of genome damage in somatic cells. The levels of DNA damage in exposed subjects determined by using alkaline comet assay were increased compared to control and showed interindividual variations. Incidence of micronuclei was also significantly increased compared to baseline control values. After short exposure of cultured lymphocytes to bleomycin, cells of occupationally exposed subjects responded with high numbers of chromatid breaks. Although the level of chromosome damage generated by bleomycin varied greatly between individuals, in exposed subjects a significantly elevated number of chromatid breaks was observed. Our results support data reported in literature indicating that microwave radiation represents a potential DNA-damaging hazard. Alkaline comet assay is confirmed as a sensitive and highly reproducible technique for detection of primary DNA damage inflicted in somatic cells. Micronucleus assay was confirmed as reliable bio-markers of effect and chromatid breakage assay as sensitive bio-marker of individual cancer susceptibility. The results obtained also confirm the necessity to improve measures and to perform accurate health surveillance of individuals occupationally exposed to microwave radiation

  10. KINETICS OF IN VIVO SISTER CHROMATID EXCHANGE INDUCTION IN MOUSE BONE MARROW CELLS BY ALKYLATING AGENTS: CYCLOPHOSPHAMIDE

    Science.gov (United States)

    Administration of cyclophosphamide (5, 10, 20 and 25 mg/kg body weight) to male CD-1 mice 2 hours after subcutaneous implantation of a 5-bromo-2'-deoxyuridine (BrdU) pellet (55 mg) resulted in a dose-dependent increase in sister chromatid exchanges (SCE) in bone marrow cells. Tre...

  11. Relationship Between Group Cohesion and Anxiety in Soccer

    OpenAIRE

    Borrego, Carla Chicau; Cid, Luis; Silva, Carlos

    2012-01-01

    Group cohesion in sport is a widely spread theme today. Research has found cohesion to be influenced by several individual and group components. Among the cognitive variables that relate to cohesion we found competitive anxiety. The purpose of this study was to examine the relation between task cohesion (ATG-T, and GI-T) and competitive state anxiety (A-state), and also if there would be a relation between cohesion and self-confidence. Participants were 366 football players of both genders ma...

  12. Micromechanical analysis of fracture processes in inelastic materials using cohesive zone approach

    International Nuclear Information System (INIS)

    Cohesive zone models (CZMs) are being increasingly used to simulate fracture and fragmentation processes in metallic, polymeric, ceramic materials and composites under thermo-mechanical, dynamic and fatigue loading. Instead of an infinitely sharp crack envisaged in fracture mechanics, CZM presupposes the presence of a fracture process zone where the energy is transferred from external work both in the forward and the wake regions of the propagating crack. We have adapted CZM approach to numerically model the inelastic fracture behavior in metallic materials. It is postulated that the forms of CZM are the manifestations of different micromechanical inelastic processes that are present in both forward and wake regions of the crack tip. In this paper, we examine the distribution of total dissipation energy, i.e. inelastic strain energy, and cohesive energy, the latter encompassing the work of fracture and other energy consuming mechanisms within the fracture process zone. It is clearly shown that the plastic energy in the material surrounding the crack is not accounted for in the cohesive energy. Thus, cohesive zone energy encompasses all the inelastic energy e.g. energy required for grain bridging, cavitations, internal sliding, surface energy but excludes any inelastic strain energy of the binding material. The effect of material parameters and form/shape of cohesive zone model in predicting the fracture behavior are also examined. Refs. 3 (author)

  13. Micromechanical modeling and inverse identification of damage using cohesive approaches

    International Nuclear Information System (INIS)

    In this study a micromechanical model is proposed for a collection of cohesive zone models embedded between two each elements of a standard cohesive-volumetric finite element method. An equivalent 'matrix-inclusions' composite is proposed as a representation of the cohesive-volumetric discretization. The overall behaviour is obtained using homogenization approaches (Hashin Shtrikman scheme and the P. Ponte Castaneda approach). The derived model deals with elastic, brittle and ductile materials. It is available whatever the triaxiality loading rate and the shape of the cohesive law, and leads to direct relationships between the overall material properties and the local cohesive parameters and the mesh density. First, rigorous bounds on the normal and tangential cohesive stiffnesses are obtained leading to a suitable control of the inherent artificial elastic loss induced by intrinsic cohesive models. Second, theoretical criteria on damageable and ductile cohesive parameters are established (cohesive peak stress, critical separation, cohesive failure energy,... ). These criteria allow a practical calibration of the cohesive zone parameters as function of the overall material properties and the mesh length. The main interest of such calibration is its promising capacity to lead to a mesh-insensitive overall response in surface damage. (author)

  14. AUTOMATIC TEXT SUMMARIZATION BASED ON TEXTUAL COHESION

    Institute of Scientific and Technical Information of China (English)

    Chen Yanmin; Liu Bingquan; Wang Xiaolong

    2007-01-01

    This paper presents two different algorithms that derive the cohesion structure in the form of lexical chains from two kinds of language resources HowNet and TongYiCiCiLin.The research that connects the cohesion structure of a text to the derivation of its summary is displayed.A novel model of automatic text summarization is devised,based on the data provided by lexicai chains from original texts.Moreover,the construction rules of lexical chains are modified according to characteristics of the knowledge database in order to be more suitable for Chinese suIninarization.Evaluation results show that high quality indicative summaries are produced from Chinese texts.

  15. Cohesion and Metaphor Aspects in Andabhuana Text

    Directory of Open Access Journals (Sweden)

    Ida Bagus Mahardika

    2015-02-01

    Full Text Available Cohesion and metaphor are the unique and interesting parts of language aspects in Andhabhuan text to research. They are quite dominant aspects in the story in developing its literature aesthetic. This research is based on the arts technical and analytical method. The result of the research on those two aspects shows that traditional aesthetic style in arts, as described in Andabhuana verses emphasize on the reference, meaning, selection and variation of words. The language parts used are aimed at bringing the text ideology to humanity perspective, especially the ?iwatattwa values as parts of Hindu teaching. Hence the cohesion and metaphor in Andabhuana text  are  semiotic description to transform to Balinese Hindus as most of them follow ?iwatattwa belief.

  16. Regional Actor Constellations in EU Cohesion Policy: Differentiation along the Policy Cycle

    Directory of Open Access Journals (Sweden)

    Achim Lang

    2011-12-01

    Full Text Available The aim of this article is to offer an empirical description and comparison of governance ar-rangements across different phases of EU cohesion policy and to offer explanations for national and regional variations in the prevalence of governance arrangements in non-Cohesion (Ger-many and Italy, old Cohesion (Greece and Spain, and CEE countries (Czech Republic, Hungary, Poland, covering two regions for each country. Drivers of actor participation on the regional level are often linked to legal and normative requirements regarding the partnership principle. However, we concluded that Europeanization is far from being a straightforward process. The transformation of established vertical power relations within the political system as well as state-society relations at the national and sub-national level in accordance with the partnership principle are mediated by domestic and regional factors – including given respon-sibilities and administrative capabilities of regional government.

  17. Evolutionary foundations of cooperation and group cohesion

    OpenAIRE

    Frank, Steven A.

    2011-01-01

    In biology, the evolution of increasingly cooperative groups has shaped the history of life. Genes collaborate in the control of cells; cells efficiently divide tasks to produce cohesive multicellular individuals; individual members of insect colonies cooperate in integrated societies. Biological cooperation provides a foundation on which to understand human behavior. Conceptually, the economics of efficient allocation and the game-like processes of strategy are well understood in biology; we...

  18. Cohesive motion in one-dimensional flocking

    OpenAIRE

    Dossetti, V.

    2011-01-01

    A one-dimensional rule-based model for flocking, that combines velocity alignment and long-range centering interactions, is presented and studied. The induced cohesion in the collective motion of the self-propelled agents leads to a unique group behaviour that contrasts with previous studies. Our results show that the largest cluster of particles, in the condensed states, develops a mean velocity slower than the preferred one in the absence of noise. For strong noise, the system also develops...

  19. Measuring group cohesion in document collections

    OpenAIRE

    Renoust B.; Melancon G.; Viaud M.-L.

    2013-01-01

    Exploring document collections remains a focus of research. This task can be tackled using various techniques, typically ranking documents according to a relevance index or grouping documents based on various clustering algorithms. The task complexity produces results of varying quality that inevitably carry noise. Users must be careful when interpreting document relevance or groupings. We address this problem by computing cohesion measures for a group of documents confirming/infirming whether ...

  20. Group Cohesion and Performance: A Bank Analysis

    OpenAIRE

    Cristina Petronela Durneac

    2012-01-01

    This paper aims to make a contribution to understanding the role of group cohesion and group performance in financial organizations in Romania. The analysis is based on a sociological research conducted in an economic and financial organization from Bucharest. The results are rather illustrative, but they can easily find the correspondent in other Romanian financial organizations. Based on quantitative data obtained from organizational survey, the general goal of the research is to contribute...

  1. Microscopic and macroscopic compaction of cohesive powders

    OpenAIRE

    Morgeneyer, M.; Schwedes, J.; Johnson, K; Kadau, D.; Wolf, D. E.; Heim, L

    2005-01-01

    A novel method to investigate the compaction behaviour of cohesive powders is presented. As a sample, a highly porous agglomerate formed by random ballistic deposition (RBD) of micron sized spherical particles is used. A nanomanipulator deforms this small structure under scanning electron microscope observation, allowing for the tracking of individual particle motion. Defined forces are applied and the resulting deformations are measured. The hereby obtained results are compared to results fr...

  2. Social cohesion and interpersonal conflicts in projects

    OpenAIRE

    Ojiako, Udechukwu; Manville, Graham; Zouk, Nadine; Chipulu, Maxwell

    2016-01-01

    One particular area of project management literature that has continued to gain momentum in literature is its social dimension; with a number of scholars emphasising the fact that there is a considerable social dimension to every project activity. Within this context, the authors examine parameters that drive social facets of projects with a particular focus on social cohesion, interpersonal conflicts and national culture. Data from 167 project managers working in Kuwait were collected utilis...

  3. Dimerization of CPAP Orchestrates Centrosome Cohesion Plasticity*

    OpenAIRE

    Zhao, Lingli; Jin, Changjiang; Chu, Youjun; Varghese, Chris; Hua, Shasha; Yan, Feng; Miao, Yong; Liu, Jing; Mann, David; Ding, Xia; Zhang, Jiancun; Wang, Zhiyong; Dou, Zhen; Yao, XueBiao

    2009-01-01

    Centrosome cohesion and segregation are accurately regulated to prevent an aberrant separation of duplicated centrosomes and to ensure the correct formation of bipolar spindles by a tight coupling with cell cycle machinery. CPAP is a centrosome protein with five coiled-coil domains and plays an important role in the control of brain size in autosomal recessive primary microcephaly. Previous studies showed that CPAP interacts with tubulin and controls centriole length. Here, we reported that C...

  4. Force transmission in cohesive granular media

    Science.gov (United States)

    Radjai, Farhang; Topin, Vincent; Richefeu, Vincent; Voivret, Charles; Delenne, Jean-Yves; Azéma, Emilien; El Youssoufi, Said

    2010-05-01

    We use numerical simulations to investigate force and stress transmission in cohesive granular media covering a wide class of materials encountered in nature and industrial processing. The cohesion results either from capillary bridges between particles or from the presence of a solid binding matrix filling fully or partially the interstitial space. The liquid bonding is treated by implementing a capillary force law within a debonding distance between particles and simulated by the discrete element method. The solid binding matrix is treated by means of the Lattice Element Method (LEM) based on a lattice-type discretization of the particles and matrix. Our data indicate that the exponential fall-off of strong compressive forces is a generic feature of both cohesive and noncohesive granular media both for liquid and solid bonding. The tensile forces exhibit a similar decreasing exponential distribution, suggesting that this form basically reflects granular disorder. This is consistent with the finding that not only the contact forces but also the stress components in the bulk of the particles and matrix, accessible from LEM simulations in the case of solid bonding, show an exponential fall-off. We also find that the distribution of weak compressive forces is sensitive to packing anisotropy, particle shape and particle size distribution. In the case of wet packings, we analyze the self-equilibrated forces induced by liquid bonds and show that the positive and negative particle pressures form a bi-percolating structure.

  5. An increase in telomere sister chromatid exchange in murine embryonic stem cells possessing critically shortened telomeres

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yisong [ORNL; Giannone, Richard J [ORNL; Wu, Jun [ORNL; Gomez, Marla V [ORNL; Liu, Yie [ORNL

    2005-01-01

    Telomerase deficiency leads to a progressive loss of telomeric DNA that eventually triggers cell apoptosis in human primary cells during prolonged growth in culture. Rare survivors can maintain telomere length through either activation of telomerase or recombination-based telomere lengthening, and thus proliferate indefinitely. We have explored the possibility that telomeres may be maintained through telomere sister chromatid exchange (T-SCE) in murine telomere reverse transcriptase-deficient (mTert -/-) splenocytes and ES cells. Because telomerase deficiency leads to gradual loss of telomeric DNA in mTert -/- splenocytes and ES cells and eventually to chromosomes with telomere signal-free ends (SFEs), we examined these cell types for evidence of sister chromatid exchange at telomeres, and observed an increase in T-SCEs only in a subset of mTert -/- splenocytes or ES cells that possessed multiple SFEs. Furthermore, T-SCEs were more often detected in ES cells than in splenocytes that harbored a similar frequency of SFEs. In mTert heterozygous (mTert +/-) ES cells or splenocytes, which are known to exhibit a decrease in average telomere length but no SFEs, no increase in T-SCE was observed. In addition to T-SCE, other genomic rearrangements (i.e., SCE) were also significantly increased in mTert -/- ES cells possessing critically short telomeres, but not in splenocytes. Our results suggest that animals and cell culture differ in their ability to carry out genomic rearrangements as a means of maintaining telomere integrity when telomeres become critically shortened.

  6. Effects of infliximab on sister chromatid exchanges and chromosomal aberration in patients with rheumatoid arthritis.

    Science.gov (United States)

    Atteritano, M; Mazzaferro, S; Mantuano, S; Bagnato, G L; Bagnato, G F

    2016-03-01

    The aim of this study was to evaluate in a 24-weeks the effect of anti-TNF-alpha, infliximab, on cytogenetic biomarkers in peripheral lymphocytes of patients with rheumatoid arthritis (RA). A total of 40 patients with RA met the criteria to be treated with methotrexate (15 mg/week) were evaluated. Twenty patients, randomly selected, were treated with infliximab in addition to methotrexate (group I), whereas the other 20 patients continued with only methotrexate treatment (group M). Twenty healthy volunteers matched for age, gender and smoking habits served as control group (group C). At baseline, sister chromatid exchange rate was 7.20 ± 2.21 in group I, 7.40 ± 1.60 in group M and 4.97 ± 1.32 in group C (P < 0.01 vs group I and M). After 24-weeks, sister chromatid exchange rate was 7.87 ± 2.54 in group I and 7.81 ± 1.95 in group M (P = ns). High frequency cells count was 4.9 % and 4.7 % in the groups I and M, respectively, at the end of the study (P = ns). The basal chromosomal aberration frequency was 4.90 % in group I and 5.20 % in groups M; after 24-weeks, this was 5.10 % in group I and 5.10 % in groups M (P = ns). Infliximab treatment, for 24 weeks, did not increase the cytogenetic biomarkers in patients with RA. Our data show that the use of infliximab has not a genotoxic effect in patients with RA. PMID:26012953

  7. In situ tensile fracture toughness of surficial cohesive marine sediments

    Science.gov (United States)

    Johnson, Bruce D.; Barry, Mark A.; Boudreau, Bernard P.; Jumars, Peter A.; Dorgan, Kelly M.

    2012-02-01

    This study reports the first in situ measurements of tensile fracture toughness, K IC, of soft, surficial, cohesive marine sediments. A newly developed probe continuously measures the stress required to cause tensile failure in sediments to depths of up to 1 m. Probe measurements are in agreement with standard laboratory methods of K IC measurements in both potter's clay and natural sediments. The data comprise in situ depth profiles from three field sites in Nova Scotia, Canada. Measured K IC at two muddy sites (median grain size of 23-50 μm) range from near zero at the sediment surface to >1,800 Pa m1/2 at 0.2 m depth. These profiles also appear to identify the bioturbated/mixed depth. K IC for a sandy site (>90% sand) is an order of magnitude lower than for the muddy sediments, and reflects the lack of cohesion/adhesion. A comparison of K IC, median grain size, and porosity in muddy sediments indicates that consolidation increases fracture strength, whereas inclusion of sand causes weakening; thus, sand-bearing layers can be easily identified in K IC profiles. K IC and vane-measured shear strength correlate strongly, which suggests that the vane measurements should perhaps be interpreted as shear fracture toughness, rather than shear strength. Comparison of in situ probe-measured values with K IC of soils and gelatin shows that sediments have a K IC range intermediate between denser compacted soils and softer, elastic gelatin.

  8. Cohesion Theory and Its Implications for English Reading Teaching

    Institute of Scientific and Technical Information of China (English)

    DU Wei-wei

    2015-01-01

    According to College English Curriculum Requirements (2007), reading is the main training aim of our college English teaching. And for the college graduates, reading is the main way through which they obtain information needed in their specialty. Most often, students think their problem in reading is vocabulary, which is not necessarily true. Sometimes even the readers look up all the new words, it is still hard for them to understand the text exactly and thoroughly. Though vocabulary plays an impor⁃ tant role in reading comprehension, it may not be the biggest hindrance on our way of correct comprehending. English reading teaching shouldn’t be confined to the teaching of vocabulary or sentences but should develop students’ability to analyze text be⁃ yond sentence level. It’s impossible to cover all the aspects of discourse analysis in one article and since cohesion is important and basic knowledge of discourse analysis, we will concentrate on the cohesive functions of discourse in English reading in this article.

  9. Separase Is Required for Homolog and Sister Disjunction during Drosophila melanogaster Male Meiosis, but Not for Biorientation of Sister Centromeres.

    Science.gov (United States)

    Blattner, Ariane C; Chaurasia, Soumya; McKee, Bruce D; Lehner, Christian F

    2016-04-01

    Spatially controlled release of sister chromatid cohesion during progression through the meiotic divisions is of paramount importance for error-free chromosome segregation during meiosis. Cohesion is mediated by the cohesin protein complex and cleavage of one of its subunits by the endoprotease separase removes cohesin first from chromosome arms during exit from meiosis I and later from the pericentromeric region during exit from meiosis II. At the onset of the meiotic divisions, cohesin has also been proposed to be present within the centromeric region for the unification of sister centromeres into a single functional entity, allowing bipolar orientation of paired homologs within the meiosis I spindle. Separase-mediated removal of centromeric cohesin during exit from meiosis I might explain sister centromere individualization which is essential for subsequent biorientation of sister centromeres during meiosis II. To characterize a potential involvement of separase in sister centromere individualization before meiosis II, we have studied meiosis in Drosophila melanogaster males where homologs are not paired in the canonical manner. Meiosis does not include meiotic recombination and synaptonemal complex formation in these males. Instead, an alternative homolog conjunction system keeps homologous chromosomes in pairs. Using independent strategies for spermatocyte-specific depletion of separase complex subunits in combination with time-lapse imaging, we demonstrate that separase is required for the inactivation of this alternative conjunction at anaphase I onset. Mutations that abolish alternative homolog conjunction therefore result in random segregation of univalents during meiosis I also after separase depletion. Interestingly, these univalents become bioriented during meiosis II, suggesting that sister centromere individualization before meiosis II does not require separase. PMID:27120695

  10. Coaches' Perceptions of Team Cohesion in Paralympic Sports.

    Science.gov (United States)

    Falcão, William R; Bloom, Gordon A; Loughead, Todd M

    2015-07-01

    The purpose of this study was to investigate Paralympic coaches' perceptions of team cohesion. Seven head coaches of summer and winter Canadian Paralympic sport teams participated in the study. Four participants coached individual sports and 3 coached team sports. Data were collected using semistructured interviews and analyzed using thematic analysis. The results addressed the coaches' perceptions of cohesion in the Paralympic sport setting and strategies used to foster cohesion with their teams. Participants described using techniques and strategies for enhancing cohesion that were similar to those in nondisability sport, such as task-related activities, goal setting, and regularly communicating with their athletes. They also listed how cohesion was distinct to the Paralympic setting, such as the importance of interpersonal activities to build social cohesion. The implications of these results for coaching athletes with a disability are also presented. PMID:26113550

  11. Variation of the symmetrical/asymmetrical ratio in chromatid interchanges during the various phases of the cell cycle of human lymphocytes 'in vitro'

    International Nuclear Information System (INIS)

    Experiments have been performed to verify whether in a human euploid cell system, such as lymphocyte cultures in vitro, there is a differential pattern of induction of chromatid exchanges in the various phases of the cycle. (Auth.)

  12. Mechanisms of hydraulic fracturing in cohesive soil

    Directory of Open Access Journals (Sweden)

    Jun-jie WANG

    2009-12-01

    Full Text Available Hydraulic fracturing in the soil core of earth-rockfill dams is a common problem affecting the safety of the dams. Based on fracture tests, a new criterion for hydraulic fracturing in cohesive soil was suggested. Using this criterion, the mechanisms of hydraulic fracturing in cubic soil specimens were investigated. The results indicate that the propagation of the crack in a cubic specimen under water pressure occurs in a mixed mode I-II if the crack face is not perpendicular to any of the principal stresses, and the crack most likely to propagate is the one that is perpendicular to the minor principal stress and propagates in mode I.

  13. Mechanisms of hydraulic fracturing in cohesive soil

    OpenAIRE

    Wang, Jun-Jie; Zhang, Hui-ping; Ming-jie ZHAO; Lin, Xin

    2009-01-01

    Hydraulic fracturing in the soil core of earth-rockfill dams is a common problem affecting the safety of the dams. Based on fracture tests, a new criterion for hydraulic fracturing in cohesive soil was suggested. Using this criterion, the mechanisms of hydraulic fracturing in cubic soil specimens were investigated. The results indicate that the propagation of the crack in a cubic specimen under water pressure occurs in a mixed mode I-II if the crack face is not perpendicular to any of the pri...

  14. Labour migration, communities and perceptions of social cohesion in England

    OpenAIRE

    Andrews, Rhys

    2012-01-01

    textabstractAbstract The unexpected scale of labour migration from eastern Europe to the UK following EU enlargement in 2004 was thought to pose a threat to the cohesiveness of those local communities hosting larger influxes of migrants. Nevertheless, areas rich in community capacity may have been able to incorporate migrant workers in ways that sustained social cohesion. This paper explores the effects of labour migration on residents’ perceptions of social cohesion in urban areas in England...

  15. The pervasive role of biological cohesion in bedform development

    OpenAIRE

    Malarkey, Jonathan; Jaco H Baas; Hope, Julie A.; Rebecca J Aspden; Parsons, Daniel R.; Peakall, Jeff; Paterson, David M; Schindler, Robert J.; Ye, Leiping; Lichtman, Ian D.; Bass, Sarah J.; Davies, Alan G.; Manning, Andrew J.; Thorne, Peter D.

    2015-01-01

    Sediment fluxes in aquatic environments are crucially dependent on bedform dynamics. However, sediment-flux predictions rely almost completely on clean-sand studies, despite most environments being composed of mixtures of non-cohesive sands, physically cohesive muds and biologically cohesive extracellular polymeric substances (EPS) generated by microorganisms. EPS associated with surficial biofilms are known to stabilize sediment and increase erosion thresholds. Here we present experimental d...

  16. Performance through Relationships. Towards a Cohesive Virtual Intercultural Team

    OpenAIRE

    Chutnik, Monika; Grzesik, Katarzyna

    2010-01-01

    Virtual teams create challenges both for their leaders and members. What positively impacts such teams’ performance is their cohesiveness. Team cohesion is rooted both in activities of the leader and the members. Basing on literature studies, the article presents a few ways to build cohesion of a virtual intercultural team. Specifically, it covers aspects such as team atmosphere, learning and information sharing, self-image and team identity, personalities and habits, practical tools, team de...

  17. Determinants of group cohesion on the football team.

    Directory of Open Access Journals (Sweden)

    Sheriff Sarhan

    2011-10-01

    Full Text Available It is shown analysis of the determinants of cohesion and their manifestation in athletes - football players. We consider personal factors and their relationship to credible group cohesion among players. Established that the determinants of group cohesion are a factor with "emotional instability - emotional stability," the experience of the team, normative behavior (factor G, the factor Q2: «conformism - non-conformism," resistance to conflict, factor A "closed - sociability" and the factor F: «restraint - expressiveness."

  18. CONSIDERATIONS REGARDING THE TEAM COHESION IMPACT ON HANDBALL PERFORMANCE

    OpenAIRE

    TONIŢA FLORENTINA; POPESCU LAVINIA; ALEXANDRESCU NICOLETA; MACOVEI SABINA

    2012-01-01

    AbstractIntroduction. From the perspective of our paper, we consider that creating an optimum cohesion in the handball team can have favorable influences on performances.Purpose. The present study describes the theoretical premises related to the concept of “cohesion” within the handball team.Content. The cohesion influence on the group productivity has been intensely studied. High cohesion groups can easily establish performance standards and offer a wider range of awards to its members. M.E...

  19. Social cohesion – a post-crisis analysis

    OpenAIRE

    Alina Magdalena MANOLE

    2012-01-01

    Social cohesion is a complex notion, subject to various different approaches that we set out to analyse. Thus, the article presents the scientific views regarding social cohesion, both at an individual or group level and at a macro-social level. The concluding section presents the consequences for public policy of a pluralist approach to defining social cohesion, while underlining the importance of a bi-dimensional view – disparities/inequality/social exclusion and social relations/social bon...

  20. Personality in teams: its relationship to social cohesion, task cohesion, and team performance

    NARCIS (Netherlands)

    A.E.M. van Vianen; C.K.W. de Dreu

    2001-01-01

    This study continued past research on the relationship between personality composition in teams and social cohesion and team performance (Barrick, Stewart, Neubert, & Mount, 1998). Results from the Barrick et al. sample (N = 50) were compared with data from two new samples, one comprising drilling t

  1. Overtopping breaching of cohesive homogeneous earth dam with different cohesive strength

    Institute of Scientific and Technical Information of China (English)

    ZHANG JianYun; LI Yun; XUAN GuoXiang; WANG XiaoGang; LI Jun

    2009-01-01

    dumping collapse.When the cohesive strength is smaller,the breach process becomes faster,and the peak outflow,the final width and depth of breach become bigger.The main character of the breach formation is single level head cutting and shearing collapse.

  2. Do we need social cohesion to be happy?

    OpenAIRE

    KLEIN Carlo

    2011-01-01

    We consider in a first step, that social cohesion will be a determinant of income and, in a second step, income will be a determinant of subjective well-being (SWB) along with social cohesion. We propose to use the weighted Three-Stage Least Squares (3SLS) method to estimate our two steps model, based on EVS wave 2008 data for Luxembourg. The impact of social cohesion on SWB is confirmed by the effect of the socio-cultural domain of social cohesion on SWB. The formal character of the politica...

  3. Path dependence of truss-like mixed mode cohesive laws

    DEFF Research Database (Denmark)

    Goutianos, Stergios; Sørensen, Bent F.

    2012-01-01

    A general theoretical analysis is presented to prove that, under mixed mode fracture, truss-like mixed mode cohesive laws (cohesive laws that are coupled in a special manner such that the traction vector follows the separation/opening vector) are path independent only in the limited case where the...... fracture resistance (and effective traction) is independent of the phase angle of openings. To verify the theoretical analysis, a specific class of truss-like cohesive laws, coupled with a failure criterion for damage initiation and an effective opening displacement is used. It is shown analytically and...... numerically that these cohesive laws are path dependent....

  4. Onderzoek naar de inductie van chromosoomafwijkingen en "sister-chromatid exchanges" door vinyltolueen met Chinese hamster cellen in vitro

    OpenAIRE

    Knaap, van der, J.A.; A.G.A.C.; Bergkamp; W.G.M.; Groot, de, C.P.G.M.; M.G.

    1987-01-01

    Vinyltolueen induceert geen chromosoomafwijkingen in V79 Chinese hamster cellen, noch in aanwezigheid noch in afwezigheid van ratte S9 als systeem voor metabolische activering. In dezelfde cellen wordt wel een inductie van zuster chromatide uitwisselingen (SCE's) gevonden door vinyltolueen, maar alleen in aanwezigheid van metabolische activering. Er wordt verondersteld dat een tweetal metabolieten verantwoordelijk is voor de genotoxische werking van vinyltolueen.

  5. Key Skills for Science Learning: The Importance of Text Cohesion and Reading Ability

    Science.gov (United States)

    Hall, Sophie Susannah; Maltby, John; Filik, Ruth; Paterson, Kevin B.

    2016-01-01

    To explore the importance of text cohesion, we conducted two experiments. We measured online (reading times) and offline (comprehension accuracy) processes for texts that were high and low cohesion. In study one (n?=?60), we manipulated referential cohesion using noun repetition (high cohesion) and synonymy (low cohesion). Students showed enhanced…

  6. Securin and not CDK1/cyclin B1 regulates sister chromatid disjunction during meiosis II in mouse eggs.

    Science.gov (United States)

    Nabti, Ibtissem; Reis, Alexandra; Levasseur, Mark; Stemmann, Olaf; Jones, Keith T

    2008-09-15

    Mammalian eggs remain arrested at metaphase of the second meiotic division (metII) for an indeterminate time before fertilization. During this period, which can last several hours, the continued attachment of sister chromatids is thought to be achieved by inhibition of the protease separase. Separase is known to be inhibited by binding either securin or Maturation (M-Phase)-Promoting Factor, a heterodimer of CDK1/cyclin B1. However, the relative contribution of securin and CDK/cyclin B1 to sister chromatid attachment during metII arrest has not been assessed. Although there are conditions in which either CDK1/cyclinB1 activity or securin can prevent sister chromatid disjunction, principally by overexpression of non-degradable cyclin B1 or securin, we find here that separase activity is primarily regulated by securin and not CDK1/cyclin B1. Thus the CDK1 inhibitor roscovitine and an antibody we designed to block the interaction of CDK1/cyclin B1 with separase, both failed to induce sister disjunction. In contrast, securin morpholino knockdown specifically induced loss of sister attachment, that could be restored by securin cRNA rescue. During metII arrest separase appears primarily regulated by securin binding, not CDK1/cyclin B1. PMID:18639540

  7. Genetics Home Reference: Roberts syndrome

    Science.gov (United States)

    ... mechanism underlying Roberts syndrome involves loss of ESCO2 acetyltransferase activity. Hum Mol Genet. 2008 Jul 15;17( ... Zou H. Two human orthologues of Eco1/Ctf7 acetyltransferases are both required for proper sister-chromatid cohesion. ...

  8. Induction of sister chromatid exchanges in xeroderma pigmentosum cells after exposure to ultraviolet light

    International Nuclear Information System (INIS)

    The role of DNA repair mechanisms in the induction of sister chromatid exchanges (SCE) after exposure to ultraviolet radiation was investigated in xeroderma pigmentosum cells. Cells from different excision-deficient XP strains, representing the 5 complementation groups in XP, A, B, C, D and E, and from excision-proficient XP variant strains were irradiated with low doses of UVR (0-3.5 J/m2). The number of SCE was counted after two cycles in the presence of BUdR. In cells of the complementation groups A, B, C and D the number of SCE was significantly higher than in UV-exposed control cells. The frequencies of SCE in group E cells and in XP variant cells were not different from those in control cells. Treatment with caffeine (0-200 μg/ml) did not result in a different response of variant cells compared with normal cells. A simple correlation between SCE frequency and residual excision-repair activity was not observed. The response of the excision-repair deficient cells suggests that unrepaired damage, produced by UVR is involved in the production of SCE

  9. Correlation of drug-induced sister chromatid exchanges in vitro with in vivo tumor response

    International Nuclear Information System (INIS)

    A spontaneous hepatocarcinoma (HCa) grown in C/sub 3/Hf/Kam mice was used to investigate the ability of the in vitro sister chromatid exchange (SCE) assay to predict in vivo tumor sensitivity to 3 chemotherapeutic agents: melphalan, cis-Platinum, and BCNU. For HCa cells grown in monolayer culture, melphalan was the most efficient at inducing SCEs, followed by cis-Platinum, with BCNU inducing the least. According to in vitro cell survival curves, HCa was most sensitive to melphalan, less sensitive to cis-Platinum, and essentially resistant to BCNU. The relative antineoplastic effects of melphalan, cis-Platinum, and BCNU in vivo were compared by the response of artificial and spontaneous pulmonary metastases and solid tumors to these agents. BCNU had no effect on the number of artificial metastases, while there was a dose-dependent decrease in the number of lung nodules in mice treated with melphalan or cis-Platinum, with melphalan being the more effective. Spontaneous pulmonary metastases generated from HCa leg tumors were reduced in those mice treated with melphalan, unaffected by cis-Platinum, and increased by BCNU. In HCa leg tumors (5 to 6 mm in diameter), melphalan induced the longest growth delay, with cis-Platinum inducing less, and BCNU the least. Thus, the relative effects produced by these 3 drugs in vivo were the same as predicted by SCE assay in vitro

  10. A high rate of telomeric sister chromatid exchange occurs in chronic lymphocytic leukaemia B-cells.

    Science.gov (United States)

    Medves, Sandrine; Auchter, Morgan; Chambeau, Laetitia; Gazzo, Sophie; Poncet, Delphine; Grangier, Blandine; Verney, Aurélie; Moussay, Etienne; Ammerlaan, Wim; Brisou, Gabriel; Morjani, Hamid; Géli, Vincent; Palissot, Valérie; Berchem, Guy; Salles, Gilles; Wenner, Thomas

    2016-07-01

    Cancer cells protect their telomere ends from erosion through reactivation of telomerase or by using the Alternative Lengthening of Telomere (ALT) mechanism that depends on homologous recombination. Chronic lymphocytic leukaemia (CLL) B cells are characterized by almost no telomerase activity, shelterin deregulation and telomere fusions. To characterize telomeric maintenance mechanisms in B-CLL patients, we measured their telomere length, telomerase expression and the main hallmarks of the ALT activity i.e. C-circle concentration, an extra-chromosomal telomere repeat (ECTR), and the level of telomeric sister chromatid exchange (T-SCE) rate. Patients showed relative homogenous telomere length although almost no TERT transcript and nearly no C-circle were evidenced. Nevertheless, compared with normal B cells, B-CLL cells showed an increase in T-SCE rate that was correlated with a strong down-regulation of the topoisomerase III alpha (TOP3A) expression, involved in the dissolution of Holliday Junctions (HJ), together with an increased expression of SLX1A, SLX4, MUS81 and GEN1, involved in the resolution of HJ. Altogether, our results suggest that the telomere maintenance mechanism of B-CLL cells do not preferentially use telomerase or ALT. Rather, the rupture of the dissolvasome/resolvasome balance may increase telomere shuffling that could homogenize telomere length, slowing telomere erosion in this disease. PMID:26970083

  11. Health assessment of gasoline and fuel oxygenate vapors: micronucleus and sister chromatid exchange evaluations.

    Science.gov (United States)

    Schreiner, Ceinwen A; Hoffman, Gary M; Gudi, Ramadevi; Clark, Charles R

    2014-11-01

    Micronucleus and sister chromatid exchange (SCE) tests were performed for vapor condensate of baseline gasoline (BGVC), or gasoline with oxygenates, methyl tert-butyl ether (G/MTBE), ethyl tert butyl ether (G/ETBE), t-amyl methyl ether (G/TAME), diisopropyl ether (G/DIPE), t-butyl alcohol (TBA), or ethanol (G/EtOH). Sprague Dawley rats (the same 5/sex/group for both endpoints) were exposed to 0, 2000, 10,000, or 20,000mg/m(3) of each condensate, 6h/day, 5days/week over 4weeks. Positive controls (5/sex/test) were given cyclophosphamide IP, 24h prior to sacrifice at 5mg/kg (SCE test) and 40mg/kg (micronucleus test). Blood was collected from the abdominal aorta for the SCE test and femurs removed for the micronucleus test. Blood cell cultures were treated with 5μg/ml bromodeoxyuridine (BrdU) for SCE evaluation. No significant increases in micronucleated immature erythrocytes were observed for any test material. Statistically significant increases in SCE were observed in rats given BGVC alone or in female rats given G/MTBE. G/TAME induced increased SCE in both sexes at the highest dose only. Although DNA perturbation was observed for several samples, DNA damage was not expressed as increased micronuclei in bone marrow cells. Inclusion of oxygenates in gasoline did not increase the effects of gasoline alone or produce a cytogenetic hazard. PMID:24852491

  12. Effect of landfill leachate on cell cycle, micronucleus, and sister chromatid exchange in Triticum aestivum

    Energy Technology Data Exchange (ETDEWEB)

    Li Guangke; Yun Yang; Li Hongyan [Center of Environment Science and Engineering, College of Environment and Resource, Shanxi University, Taiyuan, Shanxi 030006 (China); Sang Nan [Center of Environment Science and Engineering, College of Environment and Resource, Shanxi University, Taiyuan, Shanxi 030006 (China)], E-mail: sangnan_lgkcarl@yahoo.com.cn

    2008-06-30

    With increasing use of municipal solid waste landfills for waste disposal, the leachate generated has become a serious environmental concern. Therefore, it is important to set up simple and accurate methods for monitoring leachate toxicity. In the present study, the physiological and genetic toxicity of the leachate, generated from Xingou Municipal Landfill in China, were investigated with Triticum aestivum (wheat) bioassay. The results indicate that the lower leachate concentrations stimulated the germination, growth and cell division, and did not induce obvious increase in micronucleus (MN) frequency in root tips; while the higher concentrations inhibited the processes, and significantly augmented the MN frequency in a concentration- and time-dependent manner. In addition, pycnotic cells (PNC) and sister chromatid exchange (SCE) occurred in root tips at all leachate concentrations tested, and the frequencies had positive relation with the treatment concentration and time. The results imply that components of leachate from the landfill may be genotoxic in plant cells, and exposure to leachate in the aquatic environment may pose a potential genotoxic risk to organisms. The results also suggest that the wheat bioassay is efficient, simple and reproducible in monitoring genotoxicity of the leachate.

  13. Effect of landfill leachate on cell cycle, micronucleus, and sister chromatid exchange in Triticum aestivum

    International Nuclear Information System (INIS)

    With increasing use of municipal solid waste landfills for waste disposal, the leachate generated has become a serious environmental concern. Therefore, it is important to set up simple and accurate methods for monitoring leachate toxicity. In the present study, the physiological and genetic toxicity of the leachate, generated from Xingou Municipal Landfill in China, were investigated with Triticum aestivum (wheat) bioassay. The results indicate that the lower leachate concentrations stimulated the germination, growth and cell division, and did not induce obvious increase in micronucleus (MN) frequency in root tips; while the higher concentrations inhibited the processes, and significantly augmented the MN frequency in a concentration- and time-dependent manner. In addition, pycnotic cells (PNC) and sister chromatid exchange (SCE) occurred in root tips at all leachate concentrations tested, and the frequencies had positive relation with the treatment concentration and time. The results imply that components of leachate from the landfill may be genotoxic in plant cells, and exposure to leachate in the aquatic environment may pose a potential genotoxic risk to organisms. The results also suggest that the wheat bioassay is efficient, simple and reproducible in monitoring genotoxicity of the leachate

  14. Family Structure and Cohesion, and Depressive Symptoms in Adolescents.

    Science.gov (United States)

    McKeown, Robert E.; And Others

    1997-01-01

    Assessed whether presence of both natural parents at home and level of perceived emotional bonding in the family were predictors of depressive symptoms. Found cohesion was associated with depressive symptoms after controlling for family structure and parent education, but there were significant interactions of cohesion with race and gender.…

  15. Developing Cohesive Leadership Means Addressing All Parts of the System

    Science.gov (United States)

    Fisher, Troyce

    2010-01-01

    In her role with the School Administrators of Iowa leading Iowa's leadership grant from The Wallace Foundation, the author works with a coalition of individuals and groups striving to implement a cohesive leadership system for school leaders. Efforts to create a cohesive leadership system in Iowa for the past nine years have resulted in many…

  16. Leadership Status Congruency and Cohesion in Outdoor Expedition Groups

    Science.gov (United States)

    Eys, Mark A.; Ritchie, Stephen; Little, Jim; Slade, Heather; Oddson, Bruce

    2008-01-01

    The purpose of the present study was to examine the relationship between status congruency and group cohesion in outdoor expedition groups in an educational setting. Specifically, three aspects of status congruency were assessed in relation to group cohesion in four adventure canoe groups. The groups participated in 2-week expeditions in the…

  17. Exploring Group Cohesion in a Higher Education Field Experience

    Science.gov (United States)

    Malcarne, Brian Keith

    2012-01-01

    The purpose of this study was to gain understanding into the experience of group cohesion for university students participating in an academic field experience. A mixed methods approach was used following a two-phase, sequential research design to help provide a more complete explanation of how group cohesion was impacted by the field experience.…

  18. A Study of Cohesive Devices in English IM

    Institute of Scientific and Technical Information of China (English)

    MA Shu-yun

    2011-01-01

    The main purpose of the present research is to reveal features of the use of cohesive devices in English IM (Instant Message).In order to be accurate and explicit,Oxford WordSmith Tools (Version 4.0) is applied to investigate the frequency of each type of cohesive devices used by online-communicators.Cohesion in English IM is characterized by a number of distinguishing features:1) this genre of discourse makes abundant use of cohesive ties such as personal reference,lexical reiteration and ellipsis; 2) substitution and comparative reference are rarely applied; 3) The variety of conjunctions used is limited,and the most frequently used conjunctions are and,so,but and or.In analyzing the cohesive effect of each cohesive device,it is held that in order to overcome the limitations of the messaging systems and to achieve smooth communication,participants mainly adopt explicit cohesive ties which could achieve stronger force of cohesion in IM communication.

  19. Team Cohesion, Player Attitude, and Performance Expectations in Simulation.

    Science.gov (United States)

    Wellington, William J.; Faria, A. J.

    1996-01-01

    Examines the relationship of team cohesion, participant attitude, and performance expectations to actual performance results in a simulation competition. Findings indicate a strong relationship between beginning team cohesion and performance expectations and final game performance, but little relationship between beginning participant attitudes…

  20. Community Cohesion: A Report of the Independent Review Team.

    Science.gov (United States)

    Home Office, London (England).

    This study examined the views of English citizens and community leaders regarding problems related to disaffected, disadvantaged, culturally diverse groups. The Community Cohesion Review Team (CCRT) investigated issues needing to be addressed to bring about social cohesion. Communities were deeply polarized, with separate educational systems,…

  1. Cohesion in Online Student Teams versus Traditional Teams

    Science.gov (United States)

    Hansen, David E.

    2016-01-01

    Researchers have found that the electronic methods in use for online team communication today increase communication quality in project-based work situations. Because communication quality is known to influence group cohesion, the present research examined whether online student project teams are more cohesive than traditional teams. We tested…

  2. Social and economic cohesion in Romania: an overview

    OpenAIRE

    Alina Nuta; Doinita Ariton

    2011-01-01

    Firstly, this article examines the main theoretical framework of social and economic cohesion. Secondly, our study present the real cohesion aspects, involving Romania as a member state of the European Union regional development policy as a whole, highlighting aspects of economy, population, market, workforce, education, including the context of economic crisis.

  3. Discourse Analysis: Part I, Information Management and Cohesion.

    Science.gov (United States)

    Lovejoy, Kim Brian; Lance, Donald M.

    Combining linguistics and composition studies, this paper (part 1 of a two-part article) proposes a model for the analysis of information management and cohesion in written discourse. It defines concepts of discourse analysis--specifically information management, syntax, semantic reference, lexicon, cohesion, and intonation, with examples taken…

  4. Rotational Disruption of Gravitational Aggregates with Cohesive Strength

    Science.gov (United States)

    Richardson, Derek C.; Michel, P.; Walsh, K. J.

    2007-10-01

    Recent work (Walsh and Richardson 2006, 2007) has shown that although tidal disruption of near-Earth asteroids (NEAs) can account for some of the observed binary NEAs, a second mechanism is required to explain their relatively high population percentage (about 15%; Pravec et al. 2006). Here we present results investigating whether gravitational aggregates with some cohesive strength can more easily form binaries following rotational disruption than can pure rubble piles without cohesion. Our model consists of an idealized rubble pile of equal-size rigid spheres coupled with an elastic strength law with a fixed strain cutoff limit. In the manner of Richardson et al. (2005), we explore a parameter space of initial shape and spin using a numerical code to model the subsequent evolution of hundreds of individual aggregates. We measure the spin limit for mass loss as a function of initial shape, the amount of mass loss in the case of disruption, and the efficiency of binary formation. We also characterize any binaries formed and compare with observed binary NEAs. Our initial findings will be presented. DCR and KJW acknowledge support from NSF grants AST0307549 and AST0708110. PM acknowledges support of the ESA Advanced Concepts Team on the basis of the Ariadna study 07/4111, "Asteroid Centrifugal Fragmentation." References: Pravec, P. et al. 2006. Icarus 181, 63. Richardson, D.C., Elankumaran, P., Sanderson, R.E. 2005. Icarus 173, 349. Walsh, K.J., Richardson, D.C. 2006. Icarus 180, 201. Walsh, K.J., Richardson, D.C. 2007. Icarus, in press.

  5. Research on cohesive sediment erosion by flow: An overview

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Erosion of cohesive sediment by flow is a very complicated phenomenon occurring worldwide. Understanding and modeling of the erosion process are important for many issues such as the breaching of embankments, riverbank stability, siltation of harbors and navigation channels, service life of reservoirs, distribution of (heavy metal) pollutants and water quality problems. In the last few decades, numerous studies have been done on the erosion of cohesive sediment by flow. Nevertheless, the factors affecting the erosion resistance of cohesive sediment are still not fully understood and the knowledge of the physics of cohesive sediment erosion is in- adequate, as a result the mathematical modeling of this erosion is far from satis- factory. In this paper an overview of the studies on the erosion resistance, erosion threshold and the erosion rate of cohesive sediment by flow is presented. The outcomes achieved so far from the studies and the existing problems have been analyzed and summarized, based on which recommendations are proposed for future research.

  6. Relation between social cohesion and team performance in soccer teams.

    Science.gov (United States)

    Tziner, Aharon; Nicola, Nicola; Rizac, Anis

    2003-02-01

    Investigations of the influence on team performance of team composition, in terms of task-related attributes, e.g., personality traits, cognitive abilities, often assumes this relation to be mediated by the strength (intensity) of the interpersonal relations (social cohesion) among team members. However, there has been little empirical examination of how much social cohesion actually affects team outcomes. This preliminary study sought to examine this issue using soccer teams, which have been held to resemble workplace teams. Perceptions of team cohesion were collected from 198 Israeli soccer players (comprising 36 national league teams) during the week preceding their weekly games. A significant correlation was found between the perceptions of social cohesion and the results of the soccer matches, indicating a link between team social cohesion and team performance. Implications of the results, as well as the study's limitations, are discussed, and avenues for research are suggested. PMID:12705521

  7. Cohesive motion in one-dimensional flocking

    International Nuclear Information System (INIS)

    A one-dimensional rule-based model for flocking, which combines velocity alignment and long-range centering interactions, is presented and studied. The induced cohesion in the collective motion of the self-propelled agents leads to unique group behavior that contrasts with previous studies. Our results show that the largest cluster of particles, in the condensed states, develops a mean velocity slower than the preferred one in the absence of noise. For strong noise, the system also develops a non-vanishing mean velocity, alternating its direction of motion stochastically. This allows us to address the directional switching phenomenon. The effects of different sources of stochasticity on the system are also discussed. (paper)

  8. Lexicai Cohesion in Hearrt of Dartkness

    Institute of Scientific and Technical Information of China (English)

    马画

    2012-01-01

    Heart of Darkness, written by famous English novelist Joseph Conrad, is one of the most influential novellas in the 20^th century with its profound thoughts, remarkable artistry, unique double narrative structure, abundant metaphors and symbolic social meaning, has vivid stylistic features. This paper, by analyzing the novella from the angle of lexical cohesion, will help us know how the author achieves his literary meaning by making linguistic choices. The analysis of the novella from functional stylistic angle is of great stylistic siguificance and social significance. The aim of the textual analysis of Heart of Darkness is to find linguistic evidence for the reader's interpretation and the critical evaluation of the novella, which can also help college students appreciate and analyze literary texts, cultivating their ability in understanding and appreciating themes in literary works from a linguistic perspective.

  9. In situ erosion of cohesive sediment

    International Nuclear Information System (INIS)

    There has been increasing interest in tidal power schemes and the effect of a tidal energy barrage on the environment. A large man-made environmental change, such as a barrage, would be expected to have significant effects on the sediment distribution and stability of an estuary and these effects need to be assessed when considering a tidal barrage project. This report describes the development of apparatus for in-situ measurements of cohesive sediment erosion on inter-tidal mudflats. Development of the prototype field erosion bell and field testing was commissioned on behalf of the Department of Trade and Industry by the Energy Technology Support Unit (ETSU). This later work commenced in August 1991 and was completed in September 1992. (Author)

  10. Some considerations on the relationship between economic and social cohesion and implementation of the cohesion policy

    OpenAIRE

    Dziembała Małgorzata

    2016-01-01

    The processes of deepening economic integration and regional development contribute to the intensification of inter-regional disparities. The EU’s efforts to achieve cohesion are intended to contribute to lifting the level of socio-economic development, improving the quality of life of residents, and also solving emerging problems, including social ones, so that the benefits of growth spread evenly across the EU. This inevitably has the implication, in the name of solidarity principle, of the...

  11. The Role of Cohesive Particle Interactions on Solids Uniformity and Mobilization During Jet Mixing: Testing Recommendations

    International Nuclear Information System (INIS)

    Radioactive waste that is currently stored in large underground tanks at the Hanford Site will be staged in selected double-shell tanks (DSTs) and then transferred to the Waste Treatment and Immobilization Plant (WTP). Before being transferred, the waste will be mixed, sampled, and characterized to determine if the waste composition and meets the waste feed specifications. Washington River Protection Solutions is conducting a Tank Mixing and Sampling Demonstration Program to determine the mixing effectiveness of the current baseline mixing system that uses two jet mixer pumps and the adequacy of the planned sampling method. The overall purpose of the demonstration program is to mitigate the technical risk associated with the mixing and sampling systems meeting the feed certification requirements for transferring waste to the WTP. The purpose of this report is to analyze existing data and evaluate whether scaled mixing tests with cohesive simulants are needed to meet the overall objectives of the small-scale mixing demonstration program. This evaluation will focus on estimating the role of cohesive particle interactions on various physical phenomena that occur in parts of the mixing process. A specific focus of the evaluation will be on the uniformity of suspended solids in the mixed region. Based on the evaluation presented in this report and the absence of definitive studies, the recommendation is to conduct scaled mixing tests with cohesive particles and augment the initial testing with non-cohesive particles. In addition, planning for the quantitative tests would benefit from having test results from some scoping experiments that would provide results on the general behavior when cohesive inter-particle forces are important.

  12. Linear Elastic and Cohesive Fracture Analysis to Model Hydraulic Fracture in Brittle and Ductile Rocks

    Science.gov (United States)

    Yao, Yao

    2012-05-01

    Hydraulic fracturing technology is being widely used within the oil and gas industry for both waste injection and unconventional gas production wells. It is essential to predict the behavior of hydraulic fractures accurately based on understanding the fundamental mechanism(s). The prevailing approach for hydraulic fracture modeling continues to rely on computational methods based on Linear Elastic Fracture Mechanics (LEFM). Generally, these methods give reasonable predictions for hard rock hydraulic fracture processes, but still have inherent limitations, especially when fluid injection is performed in soft rock/sand or other non-conventional formations. These methods typically give very conservative predictions on fracture geometry and inaccurate estimation of required fracture pressure. One of the reasons the LEFM-based methods fail to give accurate predictions for these materials is that the fracture process zone ahead of the crack tip and softening effect should not be neglected in ductile rock fracture analysis. A 3D pore pressure cohesive zone model has been developed and applied to predict hydraulic fracturing under fluid injection. The cohesive zone method is a numerical tool developed to model crack initiation and growth in quasi-brittle materials considering the material softening effect. The pore pressure cohesive zone model has been applied to investigate the hydraulic fracture with different rock properties. The hydraulic fracture predictions of a three-layer water injection case have been compared using the pore pressure cohesive zone model with revised parameters, LEFM-based pseudo 3D model, a Perkins-Kern-Nordgren (PKN) model, and an analytical solution. Based on the size of the fracture process zone and its effect on crack extension in ductile rock, the fundamental mechanical difference of LEFM and cohesive fracture mechanics-based methods is discussed. An effective fracture toughness method has been proposed to consider the fracture process zone

  13. The Role of Cohesive Particle Interactions on Solids Uniformity and Mobilization During Jet Mixing: Testing Recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Gauglitz, Phillip A.; Wells, Beric E.; Bamberger, Judith A.; Fort, James A.; Chun, Jaehun; Jenks, Jeromy WJ

    2010-04-01

    Radioactive waste that is currently stored in large underground tanks at the Hanford Site will be staged in selected double-shell tanks (DSTs) and then transferred to the Waste Treatment and Immobilization Plant (WTP). Before being transferred, the waste will be mixed, sampled, and characterized to determine if the waste composition and meets the waste feed specifications. Washington River Protection Solutions is conducting a Tank Mixing and Sampling Demonstration Program to determine the mixing effectiveness of the current baseline mixing system that uses two jet mixer pumps and the adequacy of the planned sampling method. The overall purpose of the demonstration program is to mitigate the technical risk associated with the mixing and sampling systems meeting the feed certification requirements for transferring waste to the WTP.The purpose of this report is to analyze existing data and evaluate whether scaled mixing tests with cohesive simulants are needed to meet the overall objectives of the small-scale mixing demonstration program. This evaluation will focus on estimating the role of cohesive particle interactions on various physical phenomena that occur in parts of the mixing process. A specific focus of the evaluation will be on the uniformity of suspended solids in the mixed region. Based on the evaluation presented in this report and the absence of definitive studies, the recommendation is to conduct scaled mixing tests with cohesive particles and augment the initial testing with non-cohesive particles. In addition, planning for the quantitative tests would benefit from having test results from some scoping experiments that would provide results on the general behavior when cohesive inter-particle forces are important.

  14. Correlation of energy-dependent cell cohesion with social motility in Myxococcus xanthus.

    OpenAIRE

    Shimkets, L J

    1986-01-01

    An agglutination assay was used to study cell cohesion in the myxobacterium Myxococcus xanthus. Vegetative cells agglutinated in the presence of the divalent cations Mg2+ and Ca2+. Agglutination was blocked by energy poisons that inhibit electron transport, uncouple oxidative phosphorylation, or inhibit the membrane-bound ATPase. However, energy was not required for the maintenance of cells in the multicellular aggregate. Cyanide, a strong inhibitor of agglutination, did not cause cells to di...

  15. The Relationship between Dioxin Congeners in the Breast Milk of Vietnamese Women and Sister Chromatid Exchange

    Directory of Open Access Journals (Sweden)

    Hiroyuki Suzuki

    2014-04-01

    Full Text Available The aim of this study was to clarify the relationship between dioxin concentrations in breast milk and the sister chromatid exchange (SCE frequency in women from herbicide-sprayed and non sprayed areas. Blood samples were taken from 21 women with high TCDD (tetrachlorodibenzo-p-dioxin levels from sprayed areas, 23 women with moderate TCDD levels from sprayed areas, and 19 women from non sprayed areas to determine their SCE frequency. The SCE frequencies for the high and moderate TCDD groups from the sprayed area and for the non sprayed area group were 2.40, 2.19, and 1.48 per cell, respectively. Multiple regression analysis showed that the standardized β values for 1,2,3,6,7,8-hexaCDD (β = 0.60, 1,2,3,4,6,7,8-heptaCDD (β = 0.64, and octaCDD (β = 0.65 were higher than those for TCDD (β = 0.34 and 1,2,3,7,8-pentaCDD (β = 0.42. The adjusted R2 value for polyCDDs (R2 = 0.38 was higher than that for polyCDD toxic equivalents (TEQ (toxic equivalents; R2 = 0.23. This study therefore shows that levels of hexa-, hepta-, and octaCDD, which were previously regarded as being less toxic than TCDD, are closely related to SCE frequency and that the level of dioxin (pg/g lipid is potentially more useful as an indicator than TEQ value for explaining SCE frequency.

  16. The lethal response to Cdk1 inhibition depends on sister chromatid alignment errors generated by KIF4 and isoform 1 of PRC1.

    Science.gov (United States)

    Voets, Erik; Marsman, Judith; Demmers, Jeroen; Beijersbergen, Roderick; Wolthuis, Rob

    2015-01-01

    Cyclin-dependent kinase 1 (Cdk1) is absolutely essential for cell division. Complete ablation of Cdk1 precludes the entry of G2 phase cells into mitosis, and is early embryonic lethal in mice. Dampening Cdk1 activation, by reducing gene expression or upon treatment with cell-permeable Cdk1 inhibitors, is also detrimental for proliferating cells, but has been associated with defects in mitotic progression, and the formation of aneuploid daughter cells. Here, we used a large-scale RNAi screen to identify the human genes that critically determine the cellular toxicity of Cdk1 inhibition. We show that Cdk1 inhibition leads to fatal sister chromatid alignment errors and mitotic arrest in the spindle checkpoint. These problems start early in mitosis and are alleviated by depletion of isoform 1 of PRC1 (PRC1-1), by gene ablation of its binding partner KIF4, or by abrogation of KIF4 motor activity. Our results show that, normally, Cdk1 activity must rise above the level required for mitotic entry. This prevents KIF4-dependent PRC1-1 translocation to astral microtubule tips and safeguards proper chromosome congression. We conclude that cell death in response to Cdk1 inhibitors directly relates to chromosome alignment defects generated by insufficient repression of PRC1-1 and KIF4 during prometaphase. PMID:26423135

  17. Cohesion energetics of carbon allotropes: Quantum Monte Carlo study

    International Nuclear Information System (INIS)

    We have performed quantum Monte Carlo calculations to study the cohesion energetics of carbon allotropes, including sp3-bonded diamond, sp2-bonded graphene, sp–sp2 hybridized graphynes, and sp-bonded carbyne. The computed cohesive energies of diamond and graphene are found to be in excellent agreement with the corresponding values determined experimentally for diamond and graphite, respectively, when the zero-point energies, along with the interlayer binding in the case of graphite, are included. We have also found that the cohesive energy of graphyne decreases systematically as the ratio of sp-bonded carbon atoms increases. The cohesive energy of γ-graphyne, the most energetically stable graphyne, turns out to be 6.766(6) eV/atom, which is smaller than that of graphene by 0.698(12) eV/atom. Experimental difficulty in synthesizing graphynes could be explained by their significantly smaller cohesive energies. Finally, we conclude that the cohesive energy of a newly proposed graphyne can be accurately estimated with the carbon–carbon bond energies determined from the cohesive energies of graphene and three different graphynes considered here

  18. Anchor Plates in Two-Layered Cohesion Less Soils

    Directory of Open Access Journals (Sweden)

    Hamed Niroumand

    2010-01-01

    Full Text Available Problem statement: During the past few years a great number of experimental model and numerical analysis results on the uplift resistance of anchor plate embedded in homogeneous cohesion less soil has been reported by many researchers. A review of related literature shows that not much research has been done to analyze the performance of anchor plates in layered soils a problem, which is often encountered by the professional engineers in the field. Approach: This study presented the performance of the anchor plates in the cohesion less soil by different researchers. It was based on different previous researches, from the earliest till the most recent ones. The main aim of this research was focused on the prediction of the anchor plates behavior and the force in the layered cohesion less soils. Few laboratory studies were conducted to investigate the uplift capacity behavior of cohesion less soil by previous researchers. Results: The experimental and numerical investigation included uplift test on cohesion less soil by last researchers. The embedment ratio and the effect of density on uplift response were evaluated. This analysis was investigated experimentally and numerically behavior of anchor plates buried in two layered cohesion less soil. Although earlier researchers developed experimentally expressions to estimate the uplift capacity of irregular anchor plates in layered cohesion less soils. Conclusion: The study observed that the ultimate uplift capacity is dependent on the relative strength of the two layers, the depth ratio of embedment and the upper layer thickness ratio.

  19. Relationship between group cohesion and anxiety in soccer.

    Science.gov (United States)

    Borrego, Carla Chicau; Cid, Luis; Silva, Carlos

    2012-10-01

    Group cohesion in sport is a widely spread theme today. Research has found cohesion to be influenced by several individual and group components. Among the cognitive variables that relate to cohesion we found competitive anxiety. The purpose of this study was to examine the relation between task cohesion (ATG-T, and GI-T) and competitive state anxiety (A-state), and also if there would be a relation between cohesion and self-confidence. Participants were 366 football players of both genders male and female, aged between 15 to 23 years old, from Portugal's championships. Cohesion was measured using the Portuguese version of the Group Environment Questionnaire, and to assess competitive anxiety, we used the Portuguese version of the Competition State Anxiety Inventory 2. Our results show that female athletes report experiencing more cognitive anxiety and less self-confidence than male athletes. Only cognitive anxiety relates in a significantly negative way with the perception of cohesion (GI-T e ATG-T) in the total number of participants and in male athletes. Relatively to the somatic anxiety, it only relates negatively with the perception of the integration of the group in the total number of participants and in the male gender. PMID:23487008

  20. Molecular Intercalation and Cohesion of Organic Bulk Heterojunction Photovoltaic Devices

    KAUST Repository

    Bruner, Christopher

    2013-01-17

    The phase separated bulk heterojunction (BHJ) layer in BHJ polymer:fullerene organic photovoltaic devices (OPV) are mechanically weak with low values of cohesion. Improved cohesion is important for OPV device thermomechanical reliability. BHJ devices are investigated and how fullerene intercalation within the active layer affects cohesive properties in the BHJ is shown. The intercalation of fullerenes between the side chains of the polymers poly(3,3″′-didocecyl quaterthiophene) (PQT-12) and poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT) is shown to enhance BHJ layer cohesion. Cohesion values range from ≈1 to 5 J m -2, depending on the polymer:fullerene blend, processing conditions, and composition. Devices with non-intercalated BHJ layers are found to have significantly reduced values of cohesion. The resulting device power conversion efficiencies (PCE) are also investigated and correlated with the device cohesion. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Characterizing delamination of fibre composites by mixed mode cohesive laws

    DEFF Research Database (Denmark)

    Sørensen, Bent F.; Jacobsen, Torben K.

    2009-01-01

    cohesive stresses were found to depend on both the normal and tangential crack opening displacements. The bridging laws, which are to be used together with a mode mixity dependent crack tip fracture energy, were found to possess relative low bridging stresses; the peak normal bridging stress was......A novel method is used for the determination of mixed mode cohesive laws and bridging laws for the characterisation of crack bridging in composites. The approach is based on an application of the J integral. The obtained cohesive laws were found to possess high peak stress values. Mixed mode...

  2. Chiasmata promote monopolar attachment of sister chromatids and their co-segregation toward the proper pole during meiosis I.

    Directory of Open Access Journals (Sweden)

    Yukinobu Hirose

    2011-03-01

    Full Text Available The chiasma is a structure that forms between a pair of homologous chromosomes by crossover recombination and physically links the homologous chromosomes during meiosis. Chiasmata are essential for the attachment of the homologous chromosomes to opposite spindle poles (bipolar attachment and their subsequent segregation to the opposite poles during meiosis I. However, the overall function of chiasmata during meiosis is not fully understood. Here, we show that chiasmata also play a crucial role in the attachment of sister chromatids to the same spindle pole and in their co-segregation during meiosis I in fission yeast. Analysis of cells lacking chiasmata and the cohesin protector Sgo1 showed that loss of chiasmata causes frequent bipolar attachment of sister chromatids during anaphase. Furthermore, high time-resolution analysis of centromere dynamics in various types of chiasmate and achiasmate cells, including those lacking the DNA replication checkpoint factor Mrc1 or the meiotic centromere protein Moa1, showed the following three outcomes: (i during the pre-anaphase stage, the bipolar attachment of sister chromatids occurs irrespective of chiasma formation; (ii the chiasma contributes to the elimination of the pre-anaphase bipolar attachment; and (iii when the bipolar attachment remains during anaphase, the chiasmata generate a bias toward the proper pole during poleward chromosome pulling that results in appropriate chromosome segregation. Based on these results, we propose that chiasmata play a pivotal role in the selection of proper attachments and provide a backup mechanism that promotes correct chromosome segregation when improper attachments remain during anaphase I.

  3. Inhibition of protein synthesis does not antagonize induction of UV-induced sister-chromatid exchange in xeroderma pigmentosum cells

    International Nuclear Information System (INIS)

    Cycloheximide strongly antagonizes the induction of sisterchromatid exchanges by ethyl methanesulfonate or mitomycin C in human skin fibroblast and xeroderma pigmentosum cells (group A). Analogous behavior has been observed in several other species including Chinese hamster and plant cells. This report documents an exception to that pattern: cycloheximide fails to antagonize UV-induced sister chromatid exchange in xeroderma pigmentosum cells, whereas it does in normal human skin fibroblast cells. A genetic defect in these cells is postulated to alter the UV-mediated DNA recombination process. (author)

  4. Onderzoek naar de inductie van chromosoomafwijkingen en "sister- chromatid exchanges" door methecrylamide met Chinese hamster cellen in vitro

    OpenAIRE

    Knaap, van der, J.A.; A.G.A.C.; Bergkamp; W.G.M.; Groot, de, C.P.G.M.; M.G.

    1987-01-01

    Methacrylamide is onderzocht in een test op chromosoomafwijkingen en een test op zuster-chromatide uitwisselingen (SCE's) in V79 Chinese hamster cellen in vitro ; vanwege lage toxiciteit konden hoge concentraties (tot 10 mg/ml, 117,4 mmol/l) worden getest. Methacrylamide induceerde een significate, concentratie gerelateerde toename in het aantal SCE's per cel vanaf 2,5 mg/ml (29,4 mmol/l) zowel in aan- als in afwezigheid van metabolische activering. Daarentegen zijn er onvoldoende a...

  5. Onderzoek naar de inductie van chromosoomafwijkingen en "sister- chromatid exchanges" door methylmethacrylaat met Chinese hamster cellen in vitro

    OpenAIRE

    Knaap, van der, J.A.; A.G.A.C.; Bergkamp; W.G.M.; Groot, de, C.P.G.M.; M.G.

    1986-01-01

    Methylmethacrylaat of methacrylzure-methyl-ester bleek een clastogene werking te hebben in een test op chromosoomafwijkingen met Chinese hamster cellen in vitro, zowel in afwezigheid van een systeem voor metabolische activering (S9), bij concentraties vanaf 3 ul/ml 28,2 mmol/l), als in aanwezigheid van metabolische activering (S9) bij concentraties vanaf 2 ul/ml (18,8 mmol/l). Tevens induceerde methylmethacrylaat in deze cellen een significante toename in het aantal zuster-chromatide uitwisse...

  6. Onderzoek naar de inductie van chromosoomafwijkingen en "sister- chromatid exchanges" door vinylacetaat met Chinese hamster cellen in vitro

    OpenAIRE

    Knaap, van der, J.A.; A.G.A.C.; Bergkamp; W.G.M.; Groot, de, C.P.G.M.; M.G.

    1986-01-01

    Vinylacetaat bleek een clastogene werking te hebben in een test op chromosoomafwijkingen met Chinese hamstercellen in vitro vanaf 0,25 mmol/l zowel in aan- als in afwezigheid van een systeem voor metabolische activering (S9). Tevens induceerde vinylacetaat in deze cellen een sifnificante toename in het aantal zuster-chromatide uitwisselingen (SCE's) per cel, zowel in aan als in afwezigheid van een systeem voor metabolische activering (S9) bij concentraties van 0,03125 ul/ml (respectievel...

  7. Onderzoek naar de inductie van chromosoomafwijkingen en "sister- chromatid exchanges" door acrylamide met Chinese hamster cellen in vitro

    OpenAIRE

    Knaap, van der, J.A.; A.G.A.C.; Bergkamp; W.G.M.; Groot, de, C.P.G.M.; M.G.

    1986-01-01

    Acrylamide bleek een clastogene werking te hebben in een test op chromosoomafwijkingen met Chinese hamster cellen in vitro vanaf 0,1 mg/ml (1,4 mmol/l), zowel in aan- als afwezigheid van een systeem voor metaboliosche activering (S9). Tevens induceerde acrylamide in deze cellen een significante toename in het aantal zuster-chromatide uitwisselingen (SCE's) per cel, zowel in aan- als afwezigheid van een systeem voor metabolische activering (S9) bij concentraties van 0,6 en 1 mg/ml (respec...

  8. Erythrocytes modulate cell cycle progression but not the baseline frequency of sister chromatid exchanges in pig lymphocytes

    OpenAIRE

    Miguel A. Reigosa; Sonia Soloneski; Garcia, Carlos F.; Larramendy, Marcelo L.

    1997-01-01

    The effect of co-culturing varying concentrations of pig and human red blood cells (RBCs) on the baseline frequency of sister chromatid exchanges (SCEs) and cell-cycle progression in pig plasma (PLCs) and whole blood leukocyte cultures (WBCs) was studied. No variation in SCE frequency was observed between pig control WBC and PLC. Addition of pig and human RBCs to pig PLCs did not modify the baseline frequency of SCEs. On the other hand, cell proliferation was slower in PLCs than in WBCs. The ...

  9. Design of Normal Concrete Mixtures Using Workability-Dispersion-Cohesion Method

    Directory of Open Access Journals (Sweden)

    Hisham Qasrawi

    2016-01-01

    Full Text Available The workability-dispersion-cohesion method is a new proposed method for the design of normal concrete mixes. The method uses special coefficients called workability-dispersion and workability-cohesion factors. These coefficients relate workability to mobility and stability of the concrete mix. The coefficients are obtained from special charts depending on mix requirements and aggregate properties. The method is practical because it covers various types of aggregates that may not be within standard specifications, different water to cement ratios, and various degrees of workability. Simple linear relationships were developed for variables encountered in the mix design and were presented in graphical forms. The method can be used in countries where the grading or fineness of the available materials is different from the common international specifications (such as ASTM or BS. Results were compared to the ACI and British methods of mix design. The method can be extended to cover all types of concrete.

  10. Fluidization of fine powders cohesive versus dynamical aggregation

    CERN Document Server

    Valverde Millán, José Manuel

    2012-01-01

    This book illustrates the rich phenomenology exhibited by fine powders when fluidized by a gas flow, describing novel processes to assist fluidization by helping the gas flow to mobilize and break cohesive aggregates, which help to homogenize fluidization.

  11. Collectivism, Individualism, and Cohesion in a Team-based Occupation.

    Science.gov (United States)

    Workman, Michael

    2001-01-01

    Ethnographic interviews with 3 teams of 26 computer programmers revealed how levels of collectivism or individualism differed as groups solved problems. Cultural cohesion was identified as a separate construct from collectivism. (Contains 53 references.) (SK)

  12. COHESIVE ZONE FINITE ELEMENT-BASED MODELING OF HYDRAULIC FRACTURES

    Institute of Scientific and Technical Information of China (English)

    Zuorong Chen; A.P. Bunger; Xi Zhang; Robert G. Jeffrey

    2009-01-01

    Hydraulic fracturing is a powerful technology used to stimulate fluid production from reservoirs. The fully 3-D numerical simulation of the hydraulic fracturing process is of great importance to the efficient application of this technology, but is also a great challenge because of the strong nonlinear coupling between the viscous flow of fluid and fracture propagation. By taking advantage of a cohesive zone method to simulate the fracture process, a finite element model based on the existing pore pressure cohesive finite elements has been established to investigate the propagation of a penny-shaped hydraulic fracture in an infinite elastic medium. The effect of cohesive material parameters and fluid viscosity on the hydraulic fracture behaviour has been investigated. Excellent agreement between the finite element results and analytical solutions for the limiting case where the fracture process is dominated by rock fracture toughness demonstrates the ability of the cohesive zone finite element model in simulating the hydraulic fracture growth for this case.

  13. Modelling increased soil cohesion by plant roots with EUROSEM

    Science.gov (United States)

    de Baets, S.; Poesen, J.; Torri, D.; Salvador, M. P.

    2009-04-01

    Soil cohesion is an important variable to model soil detachment by runoff (Morgan et al., 1998a). As soil particles are not loose, soil detachment by runoff will be limited by the cohesion of the soil material. It is generally recognized that plant roots contribute to the overall cohesion of the soil. Determination of this increased cohesion and soil roughness however is complicated and measurements of shear strength and soil reinforcement by plant roots are very time- and labour consuming. A model approach offers an alternative for the assessment of soil cohesion provided by plant roots However, few erosion models account for the effects of the below-ground biomass in their calculation of erosion rates. Therefore, the main objectives of this study is to develop an approach to improve an existing soil erosion model (EUROSEM) accounting for the erosion-reducing effects of roots. The approach for incorporating the root effects into this model is based on a comparison of measured soil detachment rates for bare and for root-permeated topsoil samples with predicted erosion rates under the same flow conditions using the erosion equation of EUROSEM. Through backwards calculation, transport capacity efficiencies and corresponding soil cohesion values can be assessed for bare and root-permeated topsoils respectively. The results are promising and show that grass roots provide a larger increase in soil cohesion as compared with tap-rooted species and that the increase in soil cohesion is not significantly different under wet and dry soil conditions, either for fibrous root systems or for tap root systems. Relationships are established between measured root density values and the corresponding calculated soil cohesion values, reflecting the effects of roots on the resistance of the topsoil to concentrated flow incision. These relationships enable one to incorporate the root effect into the soil erosion model EUROSEM, through adapting the soil cohesion input value. A scenario

  14. Migration and work: the cohesive role of vocational training policies

    OpenAIRE

    Ragazzi, Elena; Sella, Lisa

    2013-01-01

    Migration and work are truly connected notions, both because one major cause of migration is the search of better working conditions, and because work is a fundamental vehicle of social cohesion, especially for the migrants. Hence, the European social model strongly connects social cohesion and employment policies, fostering sustainable growth and integration by offering increasing job opportunities, particularly concerning the weak categories. Therefore, work is a pillar of active citizenshi...

  15. European territorial cohesion policies: Parallels to socialist central planning?

    OpenAIRE

    Malý Jiří; Mulíček Ondřej

    2016-01-01

    Contemporary EU territorial cohesion policy presents some striking reminders of features of socialist central planning. The objective of socio-spatial solidarity aimed at balanced spatial development is a core principle of both spatial planning doctrines. Reviewing key planning documents, this article compares territorial cohesion discourses in terms of their normative and analytical natures in order to critically evaluate the uniqueness and novelty of the current modern concept. In spite of ...

  16. Effect of cationic polyelectrolytes addition in cement cohesion

    OpenAIRE

    Edison Albert Zuluaga-Hernández; Bibian A Hoyos

    2014-01-01

    Here is studied the variation in cohesion of cement main phase (C-S-H) as a result of cationic polyelectrolytes addition (quaternary amines spermine and norspermidine). Cohesion study was carried out by molecular simulation techniques (Monte Carlo) using a primitive model in a canonical ensemble (NVT). The proposed model takes into account the influence of ionic size of each particle and the addition of polyelectrolytes with different charge number and separation. The results obtained show th...

  17. Behavioural Contagion Explains Group Cohesion in a Social Crustacean

    OpenAIRE

    Pierre Broly; Jean-Louis Deneubourg

    2015-01-01

    In gregarious species, social interactions maintain group cohesion and the associated adaptive values of group living. The understanding of mechanisms leading to group cohesion is essential for understanding the collective dynamics of groups and the spatio-temporal distribution of organisms in environment. In this view, social aggregation in terrestrial isopods represents an interesting model due to its recurrence both in the field and in the laboratory. In this study, and under a perturbatio...

  18. Influence of sociability factors on social cohesion in web forums

    OpenAIRE

    Petrovčič, Andraž; Petrič, Gregor

    2015-01-01

    Social cohesion of online communities is considered a social glue that holds together a group of people, communicating and interacting on the internet and which allows this group to efficiently confront with pressures, coming from within or outside the online community. In this paper a particular definition of social cohesion of online community is presented, which introduces its three core dimensions: participation, sense of community and interpersonal trust - concepts that are considered in...

  19. Social Cohesion Activities and Attitude Change in Cyprus

    OpenAIRE

    Direnç Kanol

    2015-01-01

    Do social cohesion activities change the attitudes of the participants? This paper uses intergroup contact theory to explore attitude change resulting from contact with out-group(s) in social cohesion activities. Results from a pre-test/post-test design with fifty-five participants in two bicommunal camps in Cyprus show how attitudes change at the immediate end of these activities; an analysis of fourteen participants’ comments after one, thirteen, and twenty-five months provides a medium- to...

  20. Conductin/axin2 and Wnt signalling regulates centrosome cohesion

    OpenAIRE

    Hadjihannas, Michel V; Brückner, Martina; Behrens, Jürgen

    2010-01-01

    Wnt signalling regulates centrosome cohesion. Work by the Behrens group shows that conductin/axin2, a negative regulator of β-catenin, localizes to centrosomes by binding to the centriole-associated component C-Nap1. Conductin/axin2 promotes centrosome cohesion by phosphorylating β-catenin at centrosomes and the authors propose a model for the regulation of centrosome separation by conductin and Wnt signalling.

  1. Oscillations in shoal cohesion in zebrafish (Danio rerio)

    OpenAIRE

    Miller, Noam Y.; Gerlai, Robert

    2008-01-01

    In many species, group cohesion may be the result of a compromise between opposing forces (e.g. predator avoidance and competition for food). However, little empirical data exists on the dynamics of group cohesion. We present moment-to-moment positional data on zebrafish shoals and analyze temporal changes in inter-individual distances. We demonstrate that the distance between shoal members does not settle at any given value, as has previously been assumed, but oscillates with a period betwee...

  2. THE COHESIVE NATURE OF THE LATE RAMESSIDE LETTERS

    Institute of Scientific and Technical Information of China (English)

    Kim; Ridealgh

    2014-01-01

    <正>1.Introduction When addressing language cohesion,an attempt must be made to identify how language is used to create cohesive and coherent communication,or how one utterance follows another.William Labov describes the task at hand,stating that‘the fundamental problem of discourse analysis1is to show how one utterance follows another in a rational,rule governed manner—in other words,how we

  3. The Process Architecture of EU Territorial Cohesion Policy

    OpenAIRE

    Andreas Faludi

    2010-01-01

    When preparing the European Spatial Development Perspective (ESDP), Member States were supported by the European Commission but denied the EU a competence in the matter. Currently, the Treaty of Lisbon identifies territorial cohesion as a competence shared between the Union and the Member States. This paper is about the process architecture of territorial cohesion policy. In the past, this architecture resembled the Open Method of Coordination (OMC) which the White Paper on European Governanc...

  4. Territorial cohesion and regional development - case of Bosnia and Herzegovina

    OpenAIRE

    Osmankovic, Jasmina; Rabija SOMUN

    2010-01-01

    Territorial cohesion and regional development - case of Bosnia and Herzegovina In paper we analyzed territorial cohesion and regional development in Bosnia and Herzegovina from 1995 to 2010. In the context this theme we analyzed convergence and disproportional into Bosnia and Herzegovina during the postwar period. We used relevant statistical methods. We focus on demographic data and standard macroeconomic data (gross domestic product, gross domestic product per capita, employment rate, unemp...

  5. Territory: An Unknown Quantity in Debates on Territorial Cohesion

    OpenAIRE

    Andreas Faludi

    2013-01-01

    There are complaints about territorial cohesion being a vague concept, but in relevant debates territory, too, figures as an unknown quantity. Thus, is it the fixed property of any state, region or local administrative unit, or is it a malleable social construct; rather than being filled with bounded territories, does space overall contain a dynamic network with fuzzy internal, as well as external boundaries, with implications for territorial cohesion? After all, if the former were to be true...

  6. Territorial efficiency of the cohesion policy in Romania

    OpenAIRE

    Mirela Ionela ACELEANU; Daniela SAHLIAN; Daniela Livia TRAŞCĂ

    2013-01-01

    Cohesion policy is one of the solutions to overcome the current crisis because the efficient use of its financial instruments determines the strengthening of the competitiveness of the European economy, the acceleration of economic growth and employment growth. The transposition of the economic and social cohesion in the territorial level is not new, but the economic development of the regions highlights that the gaps within states have widened over time. In this paper, we propose to evaluate...

  7. COHESIVE STRENGTH OF DENTIN RESISTÊNCIA COESIVA DA DENTINA

    OpenAIRE

    DEMARCO, Flávio Fernando; Turbino, Miriam Lacalle; Edmir MATSON

    1997-01-01

    The bond strength of dentin adhesives to dentin has increased after each generation. Although dentin substratum is part of the bonding process, little importance has been given to measure dentin cohesive strength. The aim of this study was to evaluate the cohesive strength of dentin in human canines. Seventeen non carious canines were selected. All of them had been extracted for more than one year. The teeth were ground until dentin square samples with approximately 2 X 2 mm were obtained. Th...

  8. Grammatical cohesion in argumentative essays by Norwegian and Russian learners

    OpenAIRE

    2010-01-01

    The theoretical framework of this thesis is based on the seminal work of Halliday and Hasan (1976). The main goal of the thesis is to reveal what types of grammatical cohesive relations are displayed in argumentative essays of academic written English. To achieve this purpose the International Corpus of Learner English (ICLE) has been chosen to study how Norwegian and Russian learners of English construct their compositions. Four major types of grammatical cohesion have been studied: referenc...

  9. Institutions, Trade, and Social Cohesion in Fragile States

    OpenAIRE

    Mina Baliamoune-Lutz

    2008-01-01

    This paper examines the contribution of institutions, social cohesion, and trade to development (per-capita income) with an emphasis on fragile states in Africa. Results from Arellano-Bond GMM estimations suggest that political institutions, openness to trade, and social cohesion affect growth in fragile states via direct and indirect mechanisms. The results indicate that, beyond a certain level, openness to trade may actually be harmful to economic performance in fragile states, particularly...

  10. The role of SEA in integrating and balancing high policy objectives in European cohesion funding programmes

    Energy Technology Data Exchange (ETDEWEB)

    Jiricka, Alexandra, E-mail: alexandra.jiricka@boku.ac.at; Proebstl, Ulrike, E-mail: ulrike.proebstl@boku.ac.at

    2013-01-15

    Funding programmes for European cohesion policy are a crucial tool to support the sustainability goals of the European Union and national policies of its member states. All these funding programmes require a Strategic Environmental Assessment (SEA) to enhance sustainable development. This article compares five first SEA applications at cohesion policy level to discuss challenges, limitations and benefits of this instrument. In order to support the SEA-process a 'Handbook on SEA for Cohesion Policy 2007-13' (GRDP 2006) was developed. The paper examines the special requirements and challenges at the programme level given the special conditions for stakeholder involvement, integration of SEA in the programme development process and strategies to cope with uncertainties to ensure real compatibility with policy goals. Using action research and in-depth interviews with SEA planners and programme managers enabled us to analyse the suitability of the methodology proposed by the handbook. The results show that some recommendations of the handbook should be changed in order to increase the transparency and to enhance the standard and comparability of the SEA-documents. Overall the SEA proved to be a rather successful tool for the integration of sustainability goals at the EU and national policy levels. Its particular strengths emerged as the process makes uncertainties visible and leads to possible redefinitions while maintaining actual policy goals. - Highlights: Black-Right-Pointing-Pointer Comparing five case studies of first applications of SEA at cohesion policy level. Black-Right-Pointing-Pointer Overall the SEA proved to be a rather successful tool for the integration of sustainability goals. Black-Right-Pointing-Pointer The study makes uncertainties visible and shows how SEA could lead to possible redefinitions.

  11. Pier and contraction scour prediction in cohesive soils at selected bridges in Illinois

    Science.gov (United States)

    Straub, Timothy D.; Over, Thomas M.

    2010-01-01

    This report presents the results of testing the Scour Rate In Cohesive Soils-Erosion Function Apparatus (SRICOS-EFA) method for estimating scour depth of cohesive soils at 15 bridges in Illinois. The SRICOS-EFA method for complex pier and contraction scour in cohesive soils has two primary components. The first component includes the calculation of the maximum contraction and pier scour (Zmax). The second component is an integrated approach that considers a time factor, soil properties, and continued interaction between the contraction and pier scour (SRICOS runs). The SRICOS-EFA results were compared to scour prediction results for non-cohesive soils based on Hydraulic Engineering Circular No. 18 (HEC-18). On average, the HEC-18 method predicted higher scour depths than the SRICOS-EFA method. A reduction factor was determined for each HEC-18 result to make it match the maximum of three types of SRICOS run results. The unconfined compressive strength (Qu) for the soil was then matched with the reduction factor and the results were ranked in order of increasing Qu. Reduction factors were then grouped by Qu and applied to each bridge site and soil. These results, and comparison with the SRICOS Zmax calculation, show that less than half of the reduction-factor method values were the lowest estimate of scour; whereas, the Zmax method values were the lowest estimate for over half. A tiered approach to predicting pier and contraction scour was developed. There are four levels to this approach numbered in order of complexity, with the fourth level being a full SRICOS-EFA analysis. Levels 1 and 2 involve the reduction factors and Zmax calculation, and can be completed without EFA data. Level 3 requires some surrogate EFA data. Levels 3 and 4 require streamflow for input into SRICOS. Estimation techniques for both EFA surrogate data and streamflow data were developed.

  12. The role of SEA in integrating and balancing high policy objectives in European cohesion funding programmes

    International Nuclear Information System (INIS)

    Funding programmes for European cohesion policy are a crucial tool to support the sustainability goals of the European Union and national policies of its member states. All these funding programmes require a Strategic Environmental Assessment (SEA) to enhance sustainable development. This article compares five first SEA applications at cohesion policy level to discuss challenges, limitations and benefits of this instrument. In order to support the SEA-process a “Handbook on SEA for Cohesion Policy 2007–13” (GRDP 2006) was developed. The paper examines the special requirements and challenges at the programme level given the special conditions for stakeholder involvement, integration of SEA in the programme development process and strategies to cope with uncertainties to ensure real compatibility with policy goals. Using action research and in-depth interviews with SEA planners and programme managers enabled us to analyse the suitability of the methodology proposed by the handbook. The results show that some recommendations of the handbook should be changed in order to increase the transparency and to enhance the standard and comparability of the SEA-documents. Overall the SEA proved to be a rather successful tool for the integration of sustainability goals at the EU and national policy levels. Its particular strengths emerged as the process makes uncertainties visible and leads to possible redefinitions while maintaining actual policy goals. - Highlights: ► Comparing five case studies of first applications of SEA at cohesion policy level. ► Overall the SEA proved to be a rather successful tool for the integration of sustainability goals. ► The study makes uncertainties visible and shows how SEA could lead to possible redefinitions.

  13. In vivo study on the replicative model validity of sister chromatid exchanges production

    International Nuclear Information System (INIS)

    The sister chromatid exchanges (SCE) frequency determination has been used as index of damage to DNA, however the biological meaning of this event is still ignored. Different models in order to explain the mechanism of their formation have been proposed and they could be contained in two categories: a) those that consider that the SCE is produced by means of discreet lesions to the DNA and that they occur in the place of the lesion, and b) those that propose that the SCE is caused by a group of lesions and that therefore the place in which they occur could not be associated with a lesion in particular. The model of Painter (1980) belongs to this last group. It suggests that the region of the DNA where the clusters are united, is the only place in which the exchange of double chain could happen during the synthesis of the DNA and makes the prediction that since the x rays retard the beginning of the duplication, the pretreatment with ionizing radiation would reduce the frequency of SCE induced by agents capable to block the lengthening of the chain of DNA, that are the most efficient SCE inducers. The objective of the present work was to establish the validity of this replicative model for the SCE formation, based in its prediction. The effect of the unilateral preexposition of mouse to gamma radiation was determined on the SCE induction by Mitomycin C (MMC), in cells of the femoral bone marrow In vivo. This strategy allows to determine the effect of the pretreatment in the same organism, minimizing the variability of the response between individuals. There was not a significant variability between the frequencies of SCE, basal and induced by gamma radiation or MMC in the same organism. The animals that received the gamma radiation pretreatment, showed a reduction of approximately the 30 % in the frequency of SCE, assuming an additive effect of the radiation with the MMC. These results coincide with the prediction of the model of Painter, however it is not

  14. Micromechanical cohesion force measurements to determine cyclopentane hydrate interfacial properties.

    Science.gov (United States)

    Aman, Zachary M; Joshi, Sanjeev E; Sloan, E Dendy; Sum, Amadeu K; Koh, Carolyn A

    2012-06-15

    Hydrate aggregation and deposition are critical factors in determining where and when hydrates may plug a deepwater flowline. We present the first direct measurement of structure II (cyclopentane) hydrate cohesive forces in the water, liquid hydrocarbon and gas bulk phases. For fully annealed hydrate particles, gas phase cohesive forces were approximately twice that obtained in a liquid hydrocarbon phase, and approximately six times that obtained in the water phase. Direct measurements show that hydrate cohesion force in a water-continuous bulk may be only the product of solid-solid cohesion. When excess water was present on the hydrate surface, gas phase cohesive forces increased by a factor of three, suggesting the importance of the liquid or quasi-liquid layer (QLL) in determining cohesive force. Hydrate-steel adhesion force measurements show that, when the steel surface is coated with hydrophobic wax, forces decrease up to 96%. As the micromechanical force technique is uniquely capable of measuring hydrate-surface forces with variable contact time, the present work contains significant implications for hydrate applications in flow assurance. PMID:22484169

  15. Detection of cohesive forces in the rubble-pile asteroid (29075) 1950 DA

    Science.gov (United States)

    Rozitis, Benjamin; MacLennan, Eric; Emery, Joshua P.

    2014-11-01

    The physical behavior of rubble-pile asteroids has traditionally been described using only gravitational and frictional forces within a granular material. Cohesive forces in the form of small van der Waals forces between constituent grains have recently been predicted to be important for small rubble-pile asteroids (less than 10 kilometers in size), and could potentially explain how small fast spinning asteroids remain intact. It is possible to infer the existence of cohesive forces within a rubble-pile asteroid by determining if it has insufficient self-gravity, dictated by its bulk density, to prevent rotational breakup by centrifugal forces. The kilometer-sized and potentially-hazardous asteroid (29075) 1950 DA is one of the largest known candidates for being held together by cohesive forces, as it has a rotation period of 2.1216 h that is just beyond the critical spin limit of 2.2 h estimated for a cohesionless asteroid. Using the Advanced Thermophysical Model (or ATPM), in combination with the radar shape model, WISE thermal-infrared data, and Yarkovsky orbital drift measurement, we determined the thermal inertia, bulk density, and cohesive strength of (29075) 1950 DA (Rozitis et al., 2014, Nature, 512, 174-176). The thermal inertia value is remarkably low at 24 +20/-14 SI units, which gives a corresponding bulk density of 1.7 ± 0.7 g/cm^3 in the Yarkovsky orbital drift analysis. This bulk density is typical of a rubble-pile asteroid, and a minimum cohesive strength of 64 +12/-20 Pa is therefore required to prevent surface mass shedding and structural failure by centrifugal forces. This strength is comparable to, though somewhat less than, the cohesive forces found between the grains of lunar regolith. Finally, as (29075) 1950 DA has a 1 in 19,800 chance of impacting the Earth in 2880, and has the potential to disrupt like main-belt comet P/2013 R3, it raises new implications for impact mitigation against fast spinning rubble-pile asteroids.

  16. Kinetics of chromatid aberrations in G2 ataxia-telangiectasia cells exposed to X-rays and ara A

    International Nuclear Information System (INIS)

    The cytogenetic effects of X-rays alone or in combination with 9-β-D-arabinofuranosyladenine (ara A) were studied in an immortalized fibroblastic line of ataxia-telangiectasia (A-T) cells. It is postulated that the kinetics of disappearance (rejoining) of chromatid deletions with postirradiation incubation time reflects the underlying repair of dsb, and is inhibited by ara A. The rejoining kinetics for deletions in A-T was similar to that found in a previous study of normal human fibroblasts (Mozdarani and Bryant 1987). The number of deletions in X-irradiated A-T cells at 1.5 h before fixation was found to be higher by a factor of approximately 2 than that found previously in normals, indicating that in A-T a higher rate of conversion of dsb into chromatid deletions occurs. The frequency of exchanges induced in G2 A-T cells was similarly enhanced but, unlike the situation in normal cells, ara A was found to cause only a slight increase in this frequency. (author)

  17. The effect of biological cohesion on current ripple development

    Science.gov (United States)

    Malarkey, Jonathan; Baas, Jaco H.; Hope, Julie

    2014-05-01

    Results are presented from laboratory experiments examining the role of biological cohesion, associated with Extra Polymeric Substances, on the development of current ripples. The results demonstrate the importance of biological cohesion compared to the effect of physical cohesion associated with clays in an otherwise sandy bed. FURTHER INFORMATION In fluvial and marine environments sediment transport is mainly dependent on the nature of the bed surface (rippled or flat) and the nature of cohesion in the bed. Cohesion can be either physical, as a result of the presence of clays, or biological as a result of the presence of organisms. In the case of the latter, biological cohesion occurs as a result of the presence of Extra Polymeric Substances (EPS) secreted by microorganisms. While it is known that EPS can dramatically increase the threshold of motion (Grant and Gust, 1987), comparatively little is known about the effect of EPS on ripple formation and development. The experiments described here seek to fill this gap. They also allow the effect of biological cohesion to be compared with that of physical cohesion from previous experiments (Baas et al., 2013). The experiments, which were conducted in a 10m flume at Bangor University, involved a current over a bed made of fine sand, with a median diameter of 0.148mm, and various amounts of xanthan gum, a proxy for naturally occurring EPS (Vardy et al., 2007). The hydrodynamic experimental conditions were matched very closely to those of Baas et al. (2013). The ripple dimensions were recorded through the glass side wall of the tank using time lapse photography. In the physical cohesion experiments of Baas et al. (2013) for clay contents up to 12%, the clay was very quickly winnowed out of the bed, leaving essentially clay-free ripples that developed at more or less the same rate as clean sand ripples. The resulting equilibrium ripples were essentially the same length as the clean sand ripples but reduced in height. By

  18. Comments on the transition between cohesive and cohesionless sediment bed exchange

    Science.gov (United States)

    Mehta, Ashish J.; Letter, Joseph V.

    2013-10-01

    The presence of both cohesive and cohesionless particles in estuarine and lacustrine sediments makes it essential to model bed exchange of both types of particles. The usual practice is to select a purely empirical estimate of particle diameter marking the transition between the two behaviors. Based on available data on particle erosion and deposition in non-oscillating flows and viscoplastic properties of bed sediment, we have attempted to examine the likelihood of identifying the transition diameter within a less empirical framework. From the relationship between diameter and bed shear stress for a variety of cohesive and cohesionless sediments, it appears that two transition diameters can be defined. One is the largest diameter of clay mineral particles at which cohesion is considered to vanish. The other is the smallest diameter at which cohesionless behavior is assumed to end at the limit of the well-known Shields' relationship extended to very fine particles. These two diameters appear to be reasonably close for mainly inorganic mineral sediments. Assuming they are equal, six zones of bed exchange are identified in terms of diameter and bed shear stress. Depending on these two variables, zones of only erosion, no erosion or deposition, and only deposition can be designated. Realistic modeling of bed exchange of multi-size sediments requires that the full range of diameters be considered. Extension of this analysis to organic-rich sediments is pending better understanding of their rheological properties.

  19. In Vitro genotoxic and antigenotoxic studies of Thai Noni fruit juice by chromosomal aberration and sister chromatid exchange assays in human lymphocytes

    OpenAIRE

    Treetip Ratanavalachai; Sumon Thitiorul; Pranee Nandhasri

    2008-01-01

    The genotoxic and antigenotoxic effects of Noni fruit juice produced in Thailand have been studied in human lymphocytes for chromosome aberration assay and sister chromatid exchange (SCE) assay in vitro. Treatment of Noni fruit juice(3.1-50 mg/ml) alone for 3 h did not significantly induce chromosomal aberration or SCE (p

  20. Britishness and Community Cohesion in Muslim News Online

    Directory of Open Access Journals (Sweden)

    Hassen ZRIBA

    2013-12-01

    Full Text Available The issues of British national identity and social cohesion have become pressing concerns within the multicultural fabric of contemporary British society. The increasing number of immigrants and their offspring, along with the maintenance of their cultural roots, seem to represent a serious defiance to social cohesion and the alleged “purity” of Britishness. A number of race related reports were produced by the official authorities to churn out the necessary steps to be followed by the British (immigrants and host community in order to keep social stability and community cohesion. Thus, the politics of community cohesion came to the fore as the neologism of contemporary British political discourse. Such new discourse of governance has been digested and processed differently by different mass media. It has been decoded, for instance, preferably by mainstream news agencies like BBC News Online. However, arguably, it is read appositionally or at best negotiatedly by ethnicity-related news agencies such as Muslim News Online. In this article, attempt has been made to adopt media discourse analysis tools to decipher the ways Muslim News Online decoded and then encoded the hegemonic official discourses of Britishness and community cohesion. A critical and interpretative approach is used to accomplish such study. The corpus of this study is primarily extracted from the website of the Muslim News Online.

  1. Research on cohesive sediment erosion by flow: An overview

    Institute of Scientific and Technical Information of China (English)

    ZHU YongHui; LU dinYou; LIAO HongZhi; WANG diaSheng; FAN BeiLin; YAO ShiMing

    2008-01-01

    Erosion of cohesive sediment by flow is a very complicated phenomenon occurring worldwide. Understanding and modeling of the erosion process are important for many issues such as the breaching of embankments, riverbank stability, siltation of harbors and navigation channels, service life of reservoirs, distribution of (heavy metal) pollutants and water quality problems. In the last few decades, numerous studies have been done on the erosion of cohesive sediment by flow. Nevertheless, the factors affecting the erosion resistance of cohesive sediment are still not fully understood and the knowledge of the physics of cohesive sediment erosion is in-adequate, as a result the mathematical modeling of this erosion is far from saris-factory. In this paper an overview of the studies on the erosion resistance, erosion threshold and the erosion rate of cohesive sediment by flow is presented. The outcomes achieved so far from the studies and the existing problems have been analyzed and summarized, based on which recommendations are proposed for future research.

  2. Frequent and efficient use of the sister chromatid for DNA double-strand break repair during budding yeast meiosis.

    Directory of Open Access Journals (Sweden)

    Tamara Goldfarb

    Full Text Available Recombination between homologous chromosomes of different parental origin (homologs is necessary for their accurate segregation during meiosis. It has been suggested that meiotic inter-homolog recombination is promoted by a barrier to inter-sister-chromatid recombination, imposed by meiosis-specific components of the chromosome axis. Consistent with this, measures of Holliday junction-containing recombination intermediates (joint molecules [JMs] show a strong bias towards inter-homolog and against inter-sister JMs. However, recombination between sister chromatids also has an important role in meiosis. The genomes of diploid organisms in natural populations are highly polymorphic for insertions and deletions, and meiotic double-strand breaks (DSBs that form within such polymorphic regions must be repaired by inter-sister recombination. Efforts to study inter-sister recombination during meiosis, in particular to determine recombination frequencies and mechanisms, have been constrained by the inability to monitor the products of inter-sister recombination. We present here molecular-level studies of inter-sister recombination during budding yeast meiosis. We examined events initiated by DSBs in regions that lack corresponding sequences on the homolog, and show that these DSBs are efficiently repaired by inter-sister recombination. This occurs with the same timing as inter-homolog recombination, but with reduced (2- to 3-fold yields of JMs. Loss of the meiotic-chromosome-axis-associated kinase Mek1 accelerates inter-sister DSB repair and markedly increases inter-sister JM frequencies. Furthermore, inter-sister JMs formed in mek1Δ mutants are preferentially lost, while inter-homolog JMs are maintained. These findings indicate that inter-sister recombination occurs frequently during budding yeast meiosis, with the possibility that up to one-third of all recombination events occur between sister chromatids. We suggest that a Mek1-dependent reduction in

  3. A cohesive law for carbon nanotube/polymer interfaces based on the van der Waals force

    Science.gov (United States)

    Jiang, L. Y.; Huang, Y.; Jiang, H.; Ravichandran, G.; Gao, H.; Hwang, K. C.; Liu, B.

    2006-11-01

    We have established the cohesive law for interfaces between a carbon nanotube (CNT) and polymer that are not well bonded and are characterized by the van der Waals force. The tensile cohesive strength and cohesive energy are given in terms of the area density of carbon nanotube and volume density of polymer, as well as the parameters in the van der Waals force. For a CNT in an infinite polymer, the shear cohesive stress vanishes, and the tensile cohesive stress depends only on the opening displacement. For a CNT in a finite polymer matrix, the tensile cohesive stress remains the same, but the shear cohesive stress depends on both opening and sliding displacements, i.e., the tension/shear coupling. The simple, analytical expressions of the cohesive law are useful to study the interaction between CNT and polymer, such as in CNT-reinforced composites. The effect of polymer surface roughness on the cohesive law is also studied.

  4. Cohesiveness in financial news and its relation to market volatility.

    Science.gov (United States)

    Piškorec, Matija; Antulov-Fantulin, Nino; Novak, Petra Kralj; Mozetič, Igor; Grčar, Miha; Vodenska, Irena; Smuc, Tomislav

    2014-01-01

    Motivated by recent financial crises, significant research efforts have been put into studying contagion effects and herding behaviour in financial markets. Much less has been said regarding the influence of financial news on financial markets. We propose a novel measure of collective behaviour based on financial news on the Web, the News Cohesiveness Index (NCI), and we demonstrate that the index can be used as a financial market volatility indicator. We evaluate the NCI using financial documents from large Web news sources on a daily basis from October 2011 to July 2013 and analyse the interplay between financial markets and finance-related news. We hypothesise that strong cohesion in financial news reflects movements in the financial markets. Our results indicate that cohesiveness in financial news is highly correlated with and driven by volatility in financial markets. PMID:24849598

  5. The Effect of HRM Quality on Trust and Team Cohesion

    Directory of Open Access Journals (Sweden)

    Igor Ivašković

    2014-12-01

    Full Text Available The purpose of this study was to examine the relationships between the perceived quality of HRM, trust among athletes, their trust in head coach, and the perceived team cohesion in the context of basketball teams from four South East European countries. First, the modified version of HRM quality scale was verified on one sample of 277 athletes from 36 clubs. Then the model was developed with the theoretical fundamentals of social exchange theory and tested on data from other sample of 282 athletes from 37 basketball clubs. Results show that the perceived quality of HRM directly affects degree of athletes’ trust in the head coach. However, it does not have a direct impact on trust among athletes, neither on team cohesion. However, athletes’ trust in the head coach mediates the indirect effect between the perception of HRM and the perceived cohesiveness within the team, and it also plays the mediating role in the perceived HRM – trust among athletes’ relationships.

  6. Differential cohomology in a cohesive infinity-topos

    CERN Document Server

    Schreiber, Urs

    2013-01-01

    We formulate differential cohomology and Chern-Weil theory -- the theory of connections on fiber bundles and of gauge fields -- abstractly in the context of a certain class of higher toposes that we call "cohesive". Cocycles in this differential cohomology classify higher principal bundles equipped with cohesive structure (topological, smooth, synthetic differential, supergeometric, etc.) and equipped with connections, hence higher gauge fields. We discuss various models of the axioms and applications to fundamental notions and constructions in quantum field theory and string theory. In particular we show that the cohesive and differential refinement of universal characteristic cocycles constitutes a higher Chern-Weil homomorphism refined from secondary caracteristic classes to morphisms of higher moduli stacks of higher gauge fields, and at the same time constitutes extended geometric prequantization -- in the sense of extended/multi-tiered quantum field theory -- of hierarchies of higher dimensional Chern-S...

  7. Cohesion, consensus and extreme information in opinion dynamics

    CERN Document Server

    Sîrbu, Alina; Servedio, Vito D P; Tria, Francesca

    2013-01-01

    Opinion formation is an important element of social dynamics. It has been widely studied in the last years with tools from physics, mathematics and computer science. Here, a continuous model of opinion dynamics for multiple possible choices is analysed. Its main features are the inclusion of disagreement and possibility of modulating information, both from one and multiple sources. The interest is in identifying the effect of the initial cohesion of the population, the interplay between cohesion and information extremism, and the effect of using multiple sources of information that can influence the system. Final consensus, especially with external information, depends highly on these factors, as numerical simulations show. When no information is present, consensus or segregation is determined by the initial cohesion of the population. Interestingly, when only one source of information is present, consensus can be obtained, in general, only when this is extremely mild, i.e. there is not a single opinion stron...

  8. Photoreactivation of UV induced cell killing, chromosome aberrations, sister chromatide exchanges, mutations and pyrimidine dimers in Xenopus laevis fibroblasts

    International Nuclear Information System (INIS)

    Fibroblasts from Xenopus laevis, which posses photoreactivating enzyme were used to study the influence of photoreactivating light on the frequency of pyrimidine dimers in DNA, chromosomal aberrations, sister chromatid exchanges, cell killing and the induction of gene mutations (ouabain-resistance) induced by 254 nm ultraviolet irradiation. The frequency of all biological endpoints studied were reduced following exposure to photoreactivating light parallel to the reduction in the frequencies of pyrimidine dimers (determined as endonuclease sensitive sites). However, there was not always an absolute quantitative relationship between the reduction in the frequency of pyrimidine dimers and the reduction in the biological effects. This probably reflects a fast fixation process for the biological effects prior to removal of the dimers by photoreactivation. (orig.)

  9. Recombinant chromosome 9 possibly derived from breakage and reunion of sister chromatids within a paracentric inversion loop.

    Science.gov (United States)

    Phelan, M C; Stevenson, R E; Anderson, E V

    1993-05-15

    Chromosomally unbalanced offspring resulting from the recombination of parental paracentric inversions are uncommon. We report on a 20-month-old boy with a partial duplication of 9p due to the recombination of a paternal paracentric inversion. The patient's recombinant chromosome was designated rec(9)(p13-->p24::p12-->p24::p12-->qter). The patient's father and paternal aunt have a paracentric inversion of chromosome 9:inv(9)(p13p24). Although several mechanisms have been proposed to explain the chromosome imbalance generated from paracentric inversions, none of the previously described mechanisms can account for the structure of the recombinant chromosome observed in the propositus. We propose an unusual mechanism of formation involving breakage and unequal reunion of sister chromatids within the inversion loop to explain the structure of the patient's recombinant chromosome. PMID:8488876

  10. Test of radiation damage enhancement due to incorporation of BrUdR into DNA using chromatid aberrations

    International Nuclear Information System (INIS)

    Monte Carlo track structure calculations, leading to an estimation of the magnitude of enhancement of radiation damage due to the incorporation of the halogenated pyrimidine, bromodeoxyuridine (BrUdR) a thymine analog, into DNA have been made. The increase in the yield of double strand breaks for various degrees of substitution in one (monofilarly) or both strands (bifilarly) have been calculated. To test these calculations, quantitative selected radiation-induced aberrations have been obtained in Chinese hamster (V79) fibroblast chromosomes having various patterns of BrUdR substitution following irradiation with 250 kV X rays. Free ''breaks'' and achromatic lesions ''gaps'' show no appreciable sensitizations, but breaks involved in chromatid interchanges show significant enhancement though of lower magnitude than theoretical predictions

  11. Induction of sister-chromatid exchanges in ICR 2A frog cells exposed to 254 nm UV wavelengths

    International Nuclear Information System (INIS)

    Exposure of ICR 2A frog cells to 254 nm UV induced the formation of sister-chromatid exchanges (SCEs) in a fluence-dependent manner. Cells were also exposed to the UV produced by a fluorescent sunlamp that was filtered through 8C Mylar in order to simulate the mid-UV (290-320 nm) portion of sunlight reaching the earth's surface. In this instance, SCEs were induced in a linear fashion at low fluences but reached a plateau at a low level of induced SCEs. In addition, pretreatment of cells with the solar UV followed by exposure to 254 nm UV resulted in a significantly lower level of SCEs than in cells exposed to 254 nm UV alone. (author)

  12. Sister chromatid exchanges in X-ray irradiated blood lymphocytes from patients with hereditary diseases with radioresistant DNA synthesis

    International Nuclear Information System (INIS)

    X-ray irradiation induced sister chromatid exchanges (SCE) in blood lymphocytes from patient with Down's syndrome and adult progeria (in both the cases radioresistant DNA synthesis takes place). In normal lymphocytes (in which ionizing radiation inhibits the replicative synthesis of DNA) the rate of SCE rises with the rise of radiation dose. Thus, the rate of SCE in X-ray irradiated lymphocytes is in reverse dependence with radioresistance of replicative synthesis of DNA. The data obtained are explained in accordance with the replicative hypothesis of the SCE nature (Painter, 1980a): in cells of patients with Down's syndrome, xeroderma pigmentosum from 2 and progeria of adults the time of existence of partly replicated clusters of replicons is decreased due to radioresistant replicative synthesis of DNA, but the presence of partly replicated clusters of replicons in necessary for SCE formation. Therefore the rate of SCF in X-irradiated cells of these patients decreases

  13. Elongational rheology and cohesive fracture of photo-oxidated LDPE

    International Nuclear Information System (INIS)

    It was found recently that low-density polyethylene (LDPE) samples with different degrees of photo-oxidation represent an interesting system to study the transition from ductile to cohesive fracture and the aspects of the cohesive rupture in elongational flow. Sheets of LDPE were subjected to photo-oxidation in the presence of air using a xenon lamp to irradiate the samples for times between 1 day and 6 weeks. Characterisation methods included Fourier transform infrared spectroscopy, solvent extraction method, and rheology in shear and uniaxial extensional flows. Linear viscoelasticity was increasingly affected by increasing photo-oxidation due to crosslinking of LDPE, as corroborated by the carbonyl index, acid and aldehydes groups, and gel fraction. The molecular stress function model was used to quantify the experimental data, and the nonlinear model parameter β was found to be correlated with the gel content. The uniaxial data showed that the transition from ductile to cohesive fracture was shifted to lower elongational rates, the higher the gel content was. From 2 weeks photo-oxidation onwards, cohesive rupture occurred at every strain rate investigated. The true strain and true stress at cohesive fracture as well as the energy density applied to the sample up to fracture were analyzed. At low gel content, rupture was mainly determined by the melt fraction while at high gel content, rupture occurred predominantly in the gel structure. The strain at break was found to be independent of strain rate, contrary to the stress at break and the energy density. Thus, the true strain and not the stress at break or the energy density was found to be the relevant physical quantity to describe cohesive fracture behavior of photo-oxidated LDPE. The equilibrium modulus of the gel structures was correlated with the true strain at rupture. The stiffer the gel structure, the lower was the deformation tolerated before the sample breaks

  14. INTERACTIVE EFFECTS OF TEAM COHESION ON PERCEIVED EFFICACY IN SEMI-PROFESSIONAL SPORT

    Directory of Open Access Journals (Sweden)

    Francisco Miguel Leo Marcos

    2010-06-01

    Full Text Available The present study examined the relationships among cohesion, self-efficacy, coaches' perceptions of their players' efficacy at the individual level and athletes' perceptions of their teammates' efficacy. Participants (n = 76 recruited from four semi- professional soccer and basketball teams completed cohesiveness and efficacy questionnaires who. Data were analyzed through a correlational methodology. Results indicated significant correlations between self-efficacy and task cohesion and social cohesion. Regression analysis results suggest task cohesion positively related to coaches and teammate´s perception of efficacy. These results have implications for practitioners in terms of the importance of team building to enhance team cohesion and feelings of efficacy

  15. ALTRUISM, EGOISM AND GROUP COHESION IN A LOCAL INTERACTION MODEL

    OpenAIRE

    José A. García Martínez

    2004-01-01

    In this paper we have introduced and parameterized the concept of ?group cohesion? in a model of local interaction with a population divided into groups. This allows us to control the level of ?isolation? of these groups: We thus analyze if the degree of group cohesion is relevant to achieve an efficient behaviour and which level would be the best one for this purpose. We are interested in situations where there is a trade off between efficiency and individual incentives. This trade off is st...

  16. A Critical Discourse Analysis of the concept of social cohesion

    OpenAIRE

    Jakshøj, Christoffer; Yusuf, Ayaann Cabdi; Nielsen, Mie

    2015-01-01

    This project is puzzled by the lack of clear definitions and poorly conceptualization of the concept of social cohesion in the context of urban policy-making. Using Norman Fairclough’s ’Critical Discourse Analysis’ consisting of the three dimensions; a textual, a discursive practice, and a social practice on the Research Agenda by Social Polis. The project found that social cohesion as a concept is closely related with inclusion and solidarity, but that there is a tendency to use these term i...

  17. Cohesion of wet grains at high liquid content

    Science.gov (United States)

    Raux, Pascal; Bocquet, Lyderic; Biance, Anne-Laure

    2015-11-01

    Adding liquid to a granular medium highly increases its cohesion, due to the creation of capillary bridges between grains. From the paste obtained by mixing a large amount of water to spherical glass beads (~ 100 μm), we cast a compact beam. We study its rupture under its own weight, then deduce the cohesive strength, which increases with water content. This behavior diverges from what is expected from individual capillary bridges, suggesting a role of the liquid repartition in the granular medium. Curently at the Universidad Adolfo Ibañez (Chile).

  18. The Influence of Physical & Biological Cohesion on Dune Development

    Science.gov (United States)

    Schindler, Robert; Parsons, Daniel; Ye, Leiping; Baas, Jaco; Hope, Julie; Manning, Andy; Malarkey, Jonathan; Aspden, Rebecca; Lichtman, Dougal; Thorne, Peter; Peakall, Jeff; Patterson, David; Davies, Alan; Bass, Sarah; O'Boyle, Louise

    2014-05-01

    Existing predictions for dune bedforms are based on simplified physical parameters, with assumptions that sediment consists only of cohesionless sand. They do not include the complexities of mud: physical cohesion is imparted by cohesive clays and biological cohesion is created by the presence of organisms which, among other things, generate extra-cellular polymers (EPS). Using controlled experiments we show the profound influence on the size, development and equilibrium morphology of dune bedforms of both physical and biological cohesion. Experiments were completed at the Total Environment Simulator facility at Hull University, UK in a 10 x 2 m channel. A flat sediment bed was laid to 0.15 m depth. A unidirectional flow of 0.25 m depth was passed over the sediment for 10 h. In Phase 1 eight different sand:clay mixes were examined, where clay content was 18.0 - 2.1%. In Phase 2, the same mixtures were used with additions of EPS. A velocity of 0.8 m s-1 was used throughout, corresponding to the dune regime for the selected sand. Bedform development was monitored via ultrasonic ranging transducers, sediment cores and water samples. Phase 1 showed substantial differences in bedform type with clay content, with size inversely related to clay content, e.g. Run 1 (18.0% clay) generated 2D ripples; Run 7 (2.1% clay) generated 3D dunes. Transitional forms, included dunes with superimposed ripples, were present between these extremes. In Phase 2, EPS contents equivalent to only 1/30th of 1% by mass prevented the development of bedforms. Bedforms were generated in sediments with 1/20th and 1/10th of 1%, with an inverse relationship between bedform size and EPS content. Comparison of Phase 1 and Phase 2 runs with equal sand:mud ratios reveals that EPS acts to severely inhibit bedform development compared with the mud-only case. We can conclude that (1) the ripple-dune transition can occur under constant flow conditions, i.e. clay content may dictate bedform type, that (2) EPS

  19. Effect of processing parameters on the cohesive strength of laser surface engineered ceramic coatings on aluminum alloys

    International Nuclear Information System (INIS)

    The mechanical performance of laser surface engineered ceramic composite (TiC/Al) coating on 2024 and 6061 Al alloy substrates has been evaluated using four-point bend test. The performance of the coating is expressed in terms of the cohesive strength of the coating. Load-displacement measurements carried out during the bend test helps to determine the load corresponding to crack initiation. This load required to initiate fracture in the coating provides a measure of the strength of the coating. A simplistic approach based on elementary beam theory and strength of material in conjunction with rule of mixture was adopted to calculate the cohesive strength of the composite coating. This approach is also further extended for attempts to evaluate apparent residual stress within the coating. Since process parameters exert a significant influence in controlling the end properties of the component, the effect of laser power and laser scan speed on the cohesive strength has also been investigated. It is observed that coatings with lower scan speeds have much higher cohesive strengths and they also seem to have good metallurgical bond with the substrate thus showing better mechanical behavior than the other high scan speeds used in this present study. The apparent residual stress in the coating appears to transform from compressive to tensile in nature with increasing laser scan speed eventually contributing to delamination of the coating

  20. 3D model of radionuclide dispersion in coastal areas with multifraction cohesive and non-cohesive sediments

    Science.gov (United States)

    Brovchenko, Igor; Maderich, Vladimir; Jung, Kyung Tae

    2015-04-01

    We developed new radionuclide dispersion model that may be used in coastal areas, rivers and estuaries with non-uniform distribution of suspended and bed sediments both cohesive and non-cohesive types. Model describes radionuclides concentration in dissolved phase in water column, particulated phase on suspended sediments on each sediment class types, bed sediments and pore water. The transfer of activity between the water column and the pore water in the upper layer of the bottom sediment is governed by diffusion processes. The phase exchange between dissolved and particulate radionuclides is written in terms of desorption rate a12 (s-1) and distribution coefficient Kd,iw and Kd,ib (m3/kg) for water column and for bottom deposit, respectively. Following (Periáñez et al., 1996) the dependence of distribution coefficients is inversely proportional to the sediment particle size. For simulation of 3D circulation, turbulent diffusion and wave fields a hydrostatic model SELFE (Roland et. al. 2010) that solves Reynolds-stress averaged Navier-Stokes (RANS) equations and Wave Action transport equation on the unstructured grids was used. Simulation of suspended sediment concentration and bed sediments composition is based on (L. Pinto et. al., 2012) approach that originally was developed for non-cohesive sediments. In present study we modified this approach to include possibility of simulating mixture of cohesive and non-cohesive sediments by implementing parameterizations for erosion and deposition fluxes for cohesive sediments and by implementing flocculation model for determining settling velocity of cohesive flocs. Model of sediment transport was calibrated on measurements in the Yellow Sea which is shallow tidal basin with strongly non-uniform distribution of suspended and bed sediments. Model of radionuclide dispersion was verified on measurements of 137Cs concentration in surface water and bed sediments after Fukushima Daiichi nuclear accident. References Peri

  1. Coh-Metrix: Capturing Linguistic Features of Cohesion

    Science.gov (United States)

    McNamara, Danielle S.; Louwerse, Max M.; McCarthy, Philip M.; Graesser, Arthur C.

    2010-01-01

    This study addresses the need in discourse psychology for computational techniques that analyze text on multiple levels of cohesion and text difficulty. Discourse psychologists often investigate phenomena related to discourse processing using lengthy texts containing multiple paragraphs, as opposed to single word and sentence stimuli.…

  2. Cohesive Errors in Writing among ESL Pre-Service Teachers

    Science.gov (United States)

    Kwan, Lisa S. L.; Yunus, Melor Md

    2014-01-01

    Writing is a complex skill and one of the most difficult to master. A teacher's weak writing skills may negatively influence their students. Therefore, reinforcing teacher education by first determining pre-service teachers' writing weaknesses is imperative. This mixed-methods error analysis study aims to examine the cohesive errors in the writing…

  3. Simulation of cohesive fine powders under a plane shear

    NARCIS (Netherlands)

    Takada, Satohsi; Saitoh, K.; Hayakawa, H.

    2014-01-01

    Three-dimensional molecular-dynamics simulations of cohesive dissipative powders under a plane shear are performed. We find the various phases depending on the dimensionless shear rate and the dissipation rate as well as the density. We also find that the shape of clusters depends on the initial con

  4. Hydrodynamic instabilities in shear flows of dry cohesive granular particles

    NARCIS (Netherlands)

    Saitoh, Kuniyasu; Takada, Satoshi; Hayakawa, Hisao

    2015-01-01

    We extend the dynamic van der Waals model introduced by A. Onuki [Phys. Rev. Lett., 2005, 94, 054501] to the description of cohesive granular flows under a plane shear to study their hydrodynamic instabilities. By numerically solving the dynamic van der Waals model, we observed various heterogeneous

  5. Behavioural Contagion Explains Group Cohesion in a Social Crustacean.

    Directory of Open Access Journals (Sweden)

    Pierre Broly

    2015-06-01

    Full Text Available In gregarious species, social interactions maintain group cohesion and the associated adaptive values of group living. The understanding of mechanisms leading to group cohesion is essential for understanding the collective dynamics of groups and the spatio-temporal distribution of organisms in environment. In this view, social aggregation in terrestrial isopods represents an interesting model due to its recurrence both in the field and in the laboratory. In this study, and under a perturbation context, we experimentally tested the stability of groups of woodlice according to group size and time spent in group. Our results indicate that the response to the disturbance of groups decreases with increases in these two variables. Models neglecting social effects cannot reproduce experimental data, attesting that cohesion of aggregation in terrestrial isopods is partly governed by a social effect. In particular, models involving calmed and excited individuals and a social transition between these two behavioural states more accurately reproduced our experimental data. Therefore, we concluded that group cohesion (and collective response to stimulus in terrestrial isopods is governed by a transitory resting state under the influence of density of conspecifics and time spent in group. Lastly, we discuss the nature of direct or indirect interactions possibly implicated.

  6. Cohesion and device reliability in organic bulk heterojunction photovoltaic cells

    KAUST Repository

    Brand, Vitali

    2012-04-01

    The fracture resistance of P3HT:PC 60BM-based photovoltaic devices are characterized using quantitative adhesion and cohesion metrologies that allow identification of the weakest layer or interface in the device structure. We demonstrate that the phase separated bulk heterojunction layer is the weakest layer and report quantitative cohesion values which ranged from ∼1 to 20 J m -2. The effects of layer thickness, composition, and annealing treatments on layer cohesion are investigated. Using depth profiling and X-ray photoelectron spectroscopy on the resulting fracture surfaces, we examine the gradient of molecular components through the thickness of the bulk heterojunction layer. Finally, using atomic force microscopy we show how the topography of the failure path is related to buckling of the metal electrode and how it develops with annealing. The research provides new insights on how the molecular design, structure and composition affect the cohesive properties of organic photovoltaics. © 2011 Elsevier B.V. All rights reserved.

  7. Sense of Cohesion among Community Activists Engaging in Volunteer Activity

    Science.gov (United States)

    Levy, Drorit; Itzhaky, Haya; Zanbar, Lea; Schwartz, Chaya

    2012-01-01

    The present article attempts to shed light on the direct and indirect contribution of personal resources and community indices to Sense of Cohesion among activists engaging in community volunteer work. The sample comprised 481 activists. Based on social systems theory, three levels of variables were examined: (1) inputs, which included personal…

  8. The Process Architecture of EU Territorial Cohesion Policy

    NARCIS (Netherlands)

    Faludi, A.K.F.

    2010-01-01

    When preparing the European Spatial Development Perspective (ESDP), Member States were supported by the European Commission but denied the EU a competence in the matter. Currently, the Treaty of Lisbon identifies territorial cohesion as a competence shared between the Union and the Member States. Th

  9. Leadership, Cohesion, and Team Norms Regarding Cheating and Aggression.

    Science.gov (United States)

    Shields, David Lyle Light; And Others

    1995-01-01

    Study explored leadership, cohesion, and demographic variables in relation to team norms about cheating and aggression. Surveys of high school and college ball players indicated that older age, higher year in school, and more years playing ball correlated positively with expectations of peer cheating and aggression. (SM)

  10. Course Cohesion: An Elusive Goal for Tertiary Education

    Science.gov (United States)

    Bahr, Nan; Lloyd, Margaret

    2011-01-01

    A program's development and implementation in a higher education institution is usually launched with great fanfare, goodwill and a huge effort on the part of the whole development team to ensure a worthwhile cohesive set of learning experiences aligned to the desired course learning outcomes. It is often not long before the glue starts to come…

  11. Labour migration, communities and perceptions of social cohesion in England

    NARCIS (Netherlands)

    R. Andrews (Rhys)

    2012-01-01

    textabstractAbstract The unexpected scale of labour migration from eastern Europe to the UK following EU enlargement in 2004 was thought to pose a threat to the cohesiveness of those local communities hosting larger influxes of migrants. Nevertheless, areas rich in community capacity may have been a

  12. Long Fibre Composite Modelling Using Cohesive User's Element

    International Nuclear Information System (INIS)

    The development glass matrix composites reinforced by unidirectional long ceramic fibre has resulted in a family of very perspective structural materials. The only disadvantage of such materials is relatively high brittleness at room temperature. The main micromechanisms acting as toughening mechanism are the pull out, crack bridging, matrix cracking. There are other mechanisms as crack deflection etc. but the primer mechanism is mentioned pull out which is governed by interface between fibre and matrix. The contribution shows a way how to predict and/or optimise mechanical behaviour of composite by application of cohesive zone method and write user's cohesive element into the FEM numerical package Abaqus. The presented results from numerical calculations are compared with experimental data. Crack extension is simulated by means of element extinction algorithms. The principal effort is concentrated on the application of the cohesive zone model with the special traction separation (bridging) law and on the cohesive zone modelling. Determination of micro-mechanical parameters is based on the combination of static tests, microscopic observations and numerical calibration procedures.

  13. A Cohesive and Coherent Analysis of The Purloined Letter

    Institute of Scientific and Technical Information of China (English)

    杜娟娟; 郭鸿雁

    2013-01-01

      The thesis aims to do a research on the cohesion and coherence in The Purloined Letter written by Edgar Allan Poe based on the theories of Halliday and Hasan as well as the Chinese scholars Zhang Delu and Liu Rushan. By the means of them, Poe’s ingenious composition and vivid characters emerge in the mind of the readers.

  14. Global expression for representing cohesive-energy curves. II

    Science.gov (United States)

    Schlosser, Herbert; Ferrante, John

    1993-01-01

    Schlosser et al. (1991) showed that the R dependence of the cohesive energy of partially ionic solids may be characterized by a two-term energy relationship consisting of a Coulomb term arising from the charge transfer, delta-Z, and a scaled universal energy function, E*(a *), which accounts for the partially covalent character of the bond and for repulsion between the atomic cores for small R; a* is a scaled length. In the paper by Schlosser et al., the normalized cohesive-energy curves of NaCl-structure alkali-halide crystals were generated with this expression. In this paper we generate the cohesive-energy curves of several families of partially ionic solids with different crystal structures and differing degrees of ionicity. These include the CsCl-structure Cs halides, and the Tl and Ag halides, which have weaker ionic bonding than the alkali halides, and which have the CsCl and NaCl structures, respectively. The cohesive-energy-curve parameters are then used to generate theoretical isothermal compression curves for the Li, Na, K, Cs, and Ag halides. We find good agreement with the available experimental compression data.

  15. Territory: An Unknown Quantity in Debates on Territorial Cohesion

    Directory of Open Access Journals (Sweden)

    Andreas Faludi

    2013-08-01

    Full Text Available There are complaints about territorial cohesion being a vague concept, but in relevant debates territory, too, figures as an unknown quantity. Thus, is it the fixed property of any state, region or local administrative unit, or is it a malleable social construct; rather than being filled with bounded territories, does space overall contain a dynamic network with fuzzy internal, as well as external boundaries, with implications for territorial cohesion? After all, if the former were to be true, territorial cohesion would refer to qualities of what is inside bounded territories. If it were to be the latter, then the meaning of territorial cohesion would include qualities of the relations within a complex network of socially constructed, sometimes ephemeral constructs. There are implications for the ways subsidiarity and multi-level governance are invoked in EU discourse where there is a similar failure to question the underlying notion of territory. What is relevant here is the distinction between a ‘territorial’ and ‘relational’ geography. Considered opinion suggests that these alternatives can and, in view of the persistence of the principle of territorial representation, must be reconciled. However, though firmly entrenched, some constitutional theorists question the very principle. The debate is far from conclusive but at least it shows that discussion, even of this apparently fundamental principle is possible.

  16. Territory: An Unknown Quantity in Debates on Territorial Cohesion

    NARCIS (Netherlands)

    Faludi, A.K.F.

    2013-01-01

    There are complaints about territorial cohesion being a vague concept, but in relevant debates territory, too, figures as an unknown quantity. Thus, is it the fixed property of any state, region or local administrative unit, or is it a malleable social construct; rather than being filled with bounde

  17. Explaining Couple Cohesion in Different Types of Gay Families

    Science.gov (United States)

    van Eeden-Moorefield, Brad; Pasley, Kay; Crosbie-Burnett, Margaret; King, Erin

    2012-01-01

    This Internet-based study used data from a convenience sample of 176 gay men in current partnerships to examine differences in outness, cohesion, and relationship quality between three types of gay male couples: first cohabiting partnerships, repartnerships, and gay stepfamilies. Also, we tested whether relationship quality mediated the link…

  18. Examining the Relationship between Emotional Intelligence and Group Cohesion

    Science.gov (United States)

    Moore, Amanda; Mamiseishvili, Ketevan

    2012-01-01

    Collaborative learning experiences increase student learning, but what happens when students fail to collaborate? The authors investigated the relationship between emotional intelligence and group cohesion by studying 44 undergraduate teams who were completing semester-long projects in their business classes at a small private university in the…

  19. Measuring Cohesive Laws for Interfaces in Sandwich Structures

    DEFF Research Database (Denmark)

    Lundsgaard-Larsen, Christian; Sørensen, Bent F.; Berggreen, Carl Christian;

    2006-01-01

    Extraction of cohesive laws are conducted for interfaces in sandwich structures. Separation between face and core are driven by pure bending moments applied to double cantilever beam (DCB) specimens. By varying the ratio between moments applied to the beams the test is conducted for different mode...

  20. Understanding Social Inclusion, Social Cohesion and Social Capital

    OpenAIRE

    Robert Oxoby

    2009-01-01

    The topics of social capital, social cohesion, and social inclusion are increasingly gaining interest in economics, sociology, and politics, particularly in regards to addressing poverty and designing related policies. Here, we seek to develop the connections and interdependencies between these related concepts. We offer a framework for understanding the differences between these concepts and how they fit together in individual decision making.

  1. Social policies and structures under transition: cohesion and tensions

    Czech Academy of Sciences Publication Activity Database

    Večerník, Jiří

    2004-01-01

    Roč. 18, č. 4 (2004), s. 310-322. ISSN 1210-0455 R&D Projects: GA AV ČR IBS7028351 Institutional research plan: CEZ:AV0Z7028912 Keywords : social policy * social structure * cohesion Subject RIV: AO - Sociology, Demography

  2. Education, Social Cohesion, and the Future Role of International Organizations.

    Science.gov (United States)

    Heyneman, Stephen P.

    2003-01-01

    Summarizes social cohesion issues within education, concerns over how education performs this function, and implications for international organizations. The paper reviews the purposes of public education, discusses some modern challenges to these traditional functions and why it may be important for international organizations to assume a new…

  3. The Relationship between Task Cohesion and Competitive State Anxiety.

    Science.gov (United States)

    Eys, Mark A.; Hardy, James; Carron, Albert V.; Beauchamp, Mark R.

    2003-01-01

    Examined the association between athlete perceptions of task cohesiveness (Individual Attractions to the Group-Task and Group Integration-Task) and the degree to which they viewed their perceptions of the presence of pre-competition anxiety symptoms as facilitative or debilitative. Survey data indicated that the more positive their perceptions of…

  4. The Role of Lexical Cohesion in Writing Quality

    Directory of Open Access Journals (Sweden)

    Hmoud Alotaibi

    2015-01-01

    Full Text Available The idea of whether repetition has any relation with the writing quality of the text has remained an issue that intrigues a number of scholars in linguistics and in writing studies. Michael Hoey (1991, Halliday and Hasan (1976 are two prominent works in presenting detailed and thoughtful analysis of repetition occurrences in the text. This study uses a model of lexical cohesion proposed by Witte and Faigley (1981 which itself is based on the taxonomies of cohesive ties presented by Halliday and Hasan (1976.  The model deals with lexical cohesion and its subclasses, namely, repetition (same type, synonym, near-synonym, super-ordinate item, and general item and collocation. The corpus includes five argumentative essays written by students in the field of English language literature. Five teaching assistants were asked to rank the papers on a five-point scale based on their perception of the papers’ writing quality. The results showed that the paper that received the lowest rating in terms of the writing quality was the one that included the largest number of repetition occurrences of the same type. The study concludes by arguing that repetition may not be considered as monolithic, and suggests that every type of repetition needs to be examined individually in order to determine what enhances and what deteriorates the writing quality.Keywords: Lexical cohesion; Writing Quality; Repetition; Argumentative writing

  5. Identity in Fragile States: Social cohesion and state building

    OpenAIRE

    Seth Kaplan

    2009-01-01

    Seth Kaplan describes how understanding the relationship between identities, institutions, social cohesion, and state legitimacy is vital to spurring economic and political development in fragile states. The international community needs to stop imposing inflexible formulas for development and to start helping weak countries build on their own people's capacities for good governance.

  6. Social cohesion through football: a quasi-experimental mixed methods design to evaluate a complex health promotion program

    Directory of Open Access Journals (Sweden)

    Kemp Lynn

    2010-10-01

    also be solicited. Discussion The complexity of the Football United program poses challenges for measurement, and requires the study design to be responsive to the dynamic nature of the program and context. Assessment of change is needed at multiple levels, drawing on mixed methods and multidisciplinary approaches in implementation and evaluation. Attention to these challenges has underpinned the design and methods in the Social Cohesion through Football study, which will use a unique and innovative combination of measures that have not been applied together previously in social inclusion/cohesion and sport and social inclusion/cohesion program research.

  7. A Corpus-Based Study of Cohesion in English Medical Texts and its Chinese Translation

    OpenAIRE

    Zhao, Jia; Yan, Wenli; Zhou, Yumei

    2009-01-01

    Cohesion as an indispensable linguistic feature in discourse analysis and translation has aroused many researchers’ interest. To explore the regularity in shifting cohesive devices from English into Chinese our study was designed to analyze the similarities and differences of cohesive devices between English medical texts (EMTs) and their Chinese translation texts (CTTs). A parallel corpus consisting of 15 EMTs and 15 CTTs was established, each type of cohesive devices was identified, and pai...

  8. Coarse-Graining and Renormalization of Atomistic Binding Relations and Universal Macroscopic Cohesive Behavior

    OpenAIRE

    Nguyen, O. T.; Ortiz, M.

    2001-01-01

    We present two approaches for coarse-graining interplanar potentials and determining the corresponding macroscopic cohesive laws based on energy relaxation and the renormalization group. We analyze the cohesive behavior of a large---but finite---number of interatomic planes and find that the macroscopic cohesive law adopts a universal asymptotic form. The universal form of the macroscopic cohesive law is an attractive fixed point of a suitably-defined renormalization-group transformation.

  9. The relationship between game rules and team cohesion: an empirical study

    OpenAIRE

    Martin, Eleanor; Good, Judith

    2013-01-01

    Multiplayer games (both face-to-face and online) frequently feature teams. This study investigates whether it is possible to use the rules of a game to alter the team cohesion. Game rules from two face-to-face games were analyzed using Social Identity Theory to predict which will lead to more cohesive teams. Significant differences in team cohesion ratings given by the players after the games suggest that the game rules may indeed affect the team cohesion as predicted.

  10. Changes in Liikunnan Riemu's football team's cohesion during EUSA Games in Rotterdam

    OpenAIRE

    Pylvänäinen, Pauli

    2016-01-01

    The aim of this study was to examine Liikunnan Riemu’s football team’s changes in cohesion during European Universities Sports Association Games in Rotterdam, Netherlands. The basis for this study was to quantitatively examine cohesion using Carron’s and his colleagues (1985) developed Group Environmental Questionnaire for sport teams. The GEQ is divided into four dimensions which describe cohesion more accurately. High cohesion has been shown to lead to success in sports and v...

  11. Conceptualising and Measuring Social Cohesion in Africa: Towards a perceptions-based index

    OpenAIRE

    Langer, Arnim; Stewart, Frances; Smedts, Kristien; Demarest, Leila

    2015-01-01

    Social cohesion is a key concept in development studies. Weak social cohesion is often related to slow economic growth and (violent) conflict. So far few attempts have been made to measure this complex concept in a systematic manner. This paper introduces an innovative method to measure national-level social cohesion based on survey data from 19 African countries. We distinguish three dimensions of social cohesion; i.e. the extent of perceived inequalities, the level of societal trust, and th...

  12. Economic and Social Cohesion of EU – from Acquis to Concept

    OpenAIRE

    Dorel Ailenei

    2007-01-01

    The success of EU project depends of its economic and social cohesion. Unfortunately there are an important delay and much hesitation in official approaching of the concept of economic and social cohesion. A system theory approach is very useful to clarify the core problem of economic and social cohesion. Relating this approaching with Krugman-Venables model of spatial agglomeration, we could introduce centripetal and centrifugal forces to define a complete concept of cohesion.

  13. Cohesive zone modeling of intergranular cracking in polycrystalline aggregates

    Energy Technology Data Exchange (ETDEWEB)

    Simonovski, Igor, E-mail: Igor.Simonovski@ec.europa.eu [European Commission, DG-JRC, Institute for Energy and Transport, P.O. Box 2, NL-1755 ZG Petten (Netherlands); Cizelj, Leon, E-mail: Leon.Cizelj@ijs.si [Jožef Stefan Institute, Reactor Engineering Division, Jamova cesta 39, SI-1000 Ljubljana (Slovenia)

    2015-03-15

    Highlights: • Alternative approach to cohesive elements is proposed: cohesive-zone contact. • Applicability to measured and simulated grain structures is demonstrated. • Normal and normal/shear separation as a damage initialization is explored. • Normal/shear damage initialization significantly reduces ductility. • Little difference in Voronoi aggregate size on macroscopic response. - Abstract: Understanding and controlling early damage initiation and evolution are amongst the most important challenges in nuclear power plants, occurring in ferritic, austenitic steels and nickel based alloys. In this work a meso-scale approach to modeling initiation and evolution of early intergranular cracking is presented. This damage mechanism is present in a number of nuclear power plant components and depends on the material (e.g. composition, heat treatment, microstructure), environment and load. Finite element modeling is used to explicitly model the microstructure – both the grains and the grain boundaries. Spatial Voronoi tessellation is used to obtain the grain topology. In addition, measured topology of a 0.4 mm stainless steel wire is used. Anisotropic elasticity and crystal plasticity are used as constitutive laws for the grains. Grain boundaries are modeled using the cohesive zone approach. Different modeling assumptions/parameters are evaluated against the numerical stability criteria. The biggest positive contribution to numerical stability is the use of cohesive-type contact instead of cohesive elements. A small amount of viscous regularization should be also used along with the addition of a small amount of viscous forces to the global equilibrium equations. Two cases of grain boundary damage initiation are explored: (1) initiation due to normal separation and (2) initiation due to a combination of normal and shear separation. The second criterion significantly decreases the ductility of an aggregate and slightly improves the numerical stability.

  14. The effects of group cohesiveness on group conformity and member satisfaction

    OpenAIRE

    Kern, Wilfried

    1992-01-01

    This study investigated the effects of group cohesiveness on group conformity, and on member satisfaction. In this study, group cohesiveness, group conformity, and member satisfaction were considered to be constructs. The definition of the construct of group cohesiveness included the interrelated components of psychological closeness, interpersonal liking, group affiliation, and trust. The definition of group conformity included the components of compliance and acceptance. The ...

  15. Estimating cohesion in small groups using audio-visual nonverbal behavior

    NARCIS (Netherlands)

    H. Hung; D. Gatica-Perez

    2010-01-01

    Cohesiveness in teams is an essential part of ensuring the smooth running of task-oriented groups. Research in social psychology and management has shown that good cohesion in groups can be correlated with team effectiveness or productivity, so automatically estimating group cohesion for team traini

  16. Exploring the Effect of Background Knowledge and Text Cohesion on Learning from Texts in Computer Science

    Science.gov (United States)

    Gasparinatou, Alexandra; Grigoriadou, Maria

    2013-01-01

    In this study, we examine the effect of background knowledge and local cohesion on learning from texts. The study is based on construction-integration model. Participants were 176 undergraduate students who read a Computer Science text. Half of the participants read a text of maximum local cohesion and the other a text of minimum local cohesion.…

  17. Mixed-Mode Cohesive Damage Model Applied to the Simulation of the Mechanical Behaviour of Laminated Composite Adhesive Joints

    OpenAIRE

    de Moura, MFSF; Campilho, RDSG; Goncalves, JPM

    2009-01-01

    A study of the mechanical behaviour of laminated composite adhesive joints is presented in this paper. The study consists of both numerical simulations and experimental tests. It concentrates on single lap-shear joints made of carbon-epoxy laminated composites and an epoxy adhesive. The main objective is to verify the adequacy of cohesive damage models for the strength prediction of bonded joints. These models are attractive in modelling fracture problems since they do not require the definit...

  18. Competitive capabilities in territorially clustered firms: The strong-tied and cognitive-cohesive social network effect

    OpenAIRE

    Bárbara Larrañeta Gómez-Caminero; F. Xavier Molina-Morales

    2010-01-01

    Recent studies are supporting the idea that understanding the dynamics of firms’ value creation requires a complex and indirect association with their relational or social resources. In particular, in bounded geographical contexts this approach is replacing initial, perhaps too simplistic, assumptions. With this paper our aim is to contribute to this growing stream of research. The work focuses on the specific effects of the strength of ties and the cognitive cohesion of clustered firms on th...

  19. Cell-stage-specific enhancement by caffeine of the frequency of chromatid aberrations induced by X-rays in neutral ganglia of Drosophila melanogaster

    International Nuclear Information System (INIS)

    Caffeine (10-2 M) induced a high level of chromatid aberrations in neural ganglia of third-instar larvae of Drosophila melanogaster only when it was added to cells in late G2 and mitotic prophase. No aberrations were observed after treatment in late S-middle G2 or C-mitosis. We observed that, in these stages, caffeine strongly increased X-ray-induced damage (500 R). This potentiation was quantitatively similar. But it involved all types of aberration after treatment in C-mitosis, and essentially isochromatid deletions and chromatid exhanges after treatment in S-G2. Some hypotheses are put forth to explain the possible mechanism of action of caffeine in the potentiation of X-ray-induced damage. (orig.)

  20. Onderzoek naar de inductie van chromosoomafwijkingen en "sister- chromatid exchanges" door 2,3-epoxypropylmethacrylaat met Chinese hamster cellen in vitro

    OpenAIRE

    Knaap, van der, J.A.; A.G.A.C.; Bergkamp; W.G.M.; Groot, de, C.P.G.M.; M.G.

    1986-01-01

    2,3-epoxypropylmethacrylaat of glycidylmethacrylaat bleek een clastogene werking te hebben in een test op chromosoomafwijkingen met Chinese hamster cellen in vitro, zowel in aan- als afwezigheid van een systeem voor metabolische activering (S9), bij concentraties vanaf 0,03 ul/ml (0,23 mmol/l). Tevens induceerde 2,3-epoxypropylmethacrylaat in deze cellen een significante toename in het aantal zuster-chromatide uitwisselingen (SCE's) per cel, zowel in afwezigheid van metabolische activeri...

  1. DNA single strand breakage, DNA adducts, and sister chromatid exchange in lymphocytes and phenanthrene and pyrene metabolites in urine of coke oven workers.

    OpenAIRE

    W. Popp; Vahrenholz, C.; Schell, C; Grimmer, G.; Dettbarn, G; Kraus, R.; Brauksiepe, A; Schmeling, B; Gutzeit, T; von Bülow, J; Norpoth, K

    1997-01-01

    OBJECTIVES: To investigate the specificity of biological monitoring variables (excretion of phenanthrene and pyrene metabolites in urine) and the usefulness of some biomarkers of effect (alkaline filter elution, 32P postlabelling assay, measurement of sister chromatid exchange) in workers exposed to polycyclic aromatic hydrocarbons (PAHs). METHODS: 29 coke oven workers and a standardised control group were investigated for frequencies of DNA single strand breakage, DNA protein cross links (al...

  2. Left-right symmetry breaking in mice by left-right dynein may occur via a biased chromatid segregation mechanism, without directly involving the Nodal gene

    Directory of Open Access Journals (Sweden)

    StephanSauer

    2012-11-01

    Full Text Available Ever since cloning the classic iv mutation identified the ‘left-right dynein’ (lrd gene in mice, most research on body laterality determination has focused on its function in motile cilia at the node embryonic organizer. This model is attractive, as it links chirality of cilia architecture to asymmetry development. However, lrd is also expressed in blastocysts and embryonic stem cells, where it was shown to bias the segregation of recombined sister chromatids away from each other in mitosis. These data suggested that lrd is part of a cellular mechanism that recognizes and selectively segregates sister chromatids based on their replication history: old ‘Watson’ vs. old ‘Crick’ strands. We previously proposed that the mouse left-right axis is established via an asymmetric cell division prior to/or during gastrulation. In this model, left-right dynein selectively segregates epigenetically differentiated sister chromatids harboring a hypothetical ‘left-right axis development 1’ (‘lra1’ gene during the left-right axis establishing cell division. Here, asymmetry development would be ultimately governed by the chirality of the cytoskeleton and the DNA molecule. Our model predicts that randomization of chromatid segregation in lrd mutants should produce embryos with 25% situs solitus, 25% situs inversus, and 50% embryonic death due to heterotaxia and isomerism. Here we confirmed this prediction by using two distinct lrd mutant alleles. Other than lrd, thus far Nodal gene is the most upstream function implicated in visceral organs laterality determination. We next tested whether the Nodal gene constitutes the lra1 gene hypothesized in the model by testing mutant’s effect on 50% embryonic lethality observed in lrd mutants. Since Nodal mutation did not suppress lethality, we conclude that Nodal is not equivalent to the lra1 gene. In summary, we describe the origin of 50% lethality in lrd mutant mice not yet explained by any other

  3. IMPLICATIONS OF THE EU MULTI-LEVEL GOVERNANCE IN THE FIELD OF COMPETITION POLICY – A COMPARATIVE ANALYSIS OF THE CHARACTERISTICS OF COHESION AND COMPETITION POLICIES

    Directory of Open Access Journals (Sweden)

    Florin Bonciu

    2011-09-01

    Full Text Available The paper aims at analyzing the intrinsic characteristics of the European Union and to show that these characteristics objectively require the implementation of multi-level governance. A comparative analysis of the European Union’s cohesion and competition policy is presented from the point of view of these elements. Further on, given the implications of the economic crisis, the paper explores the possible translation from multi-level governance to polycentric governance and its implications for the cohesion and competition policies.

  4. Cohesive and anharmonic elastic properties of mixed fluorite crystals

    International Nuclear Information System (INIS)

    The cohesive and anharmonic elastic properties of four mixed fluorite crystals (CaxSr1-xF2, SrxBa1-xF2, BaxCa1-xF2 and CdxPb1-xF2) have been investigated by means of a three-body potential (TBP) model which consists of the long-range Coulomb and three-body interactions and the short-range van der Waals attraction and overlap repulsion effective upto the second neighbour ions. Due to the lack of measured data on cohesive energy, third-order elastic constants and pressure derivatives of the second-order elastic constants of mixed fluorites, the accuracy of the present results has been tested by comparing them with the so-called experimental results generated by the application of Vegard's law to their corresponding experimental values for the host fluorites. (author). 32 refs, 3 figs, 1 tab

  5. Measuring cohesive laws for interfaces in sandwich structures

    Energy Technology Data Exchange (ETDEWEB)

    Lundsgaard-Larsen, C.; Berggreen, C. [Technical Univ. of Denmark, Dept. of Mechanical Engineering, Kgs. Lyngby (Denmark); Soerensen, B.F.; Oestergaard, C. [Risoe National Lab., Materials Research Dept., Roskilde (Denmark)

    2006-07-01

    Extraction of cohesive laws are conducted for interfaces in sandwich structures. Separation between face and core are driven by pure bending moments applied to double cantilever beam (DCB) specimens. By varying the ratio between moments applied to the beams the test is conducted for different mode mixities. The sandwich specimens consists of glass fiber faces and Divinycell H200 foam core with a pre-crack between face and core made with teflon film. Arbitrary stiffening of the sandwich faces with steel bars adhered to the faces reduces rotations and ensures that the method is usable for a wide range of materials. The J integral is employed in closed form and the opening of the pre-crack tip is recorded by a commercial optical measurement system. Cohesive laws are extracted by differentiating J with respect to the normal and tangential opening of the pre-crack tip. Results for one specimen are presented and discussed. (au)

  6. Group Settling Velocity of Non-Cohesive Sediment Mixtures

    Institute of Scientific and Technical Information of China (English)

    WU Hualin; SHEN Huanting; ZHU Jianrong; ZHANG Xiaofeng

    2000-01-01

    Settling velocity is a fundamental parameter in sediment transport dynamics. For uniform par-ticles, there are abundant formulas for calculation of their settling velocities. But in natural fields, sediment consists of non-uniform particles. The interaction among particles is complex and should not be neglected. In this paper, based on the analysis of settling mechanism of non-cohesive and non-uniform particles, a theoretical model to describe settling mechanism is proposed. Besides suspension concentration andupward turbulent flow caused by other particles, collision among particles is another main factor influencing settling velocity. By introducing the collision theory, equations of fall velocity before collision, collision probability, and fall velocity after collision are established. Finally, a formula used to calculate the settling velocity of non-cohesive particles with wide grain gradation is presented, which agrees well with the experimental data.

  7. Task-Based Cohesive Evolution of Dynamic Brain Networks

    Science.gov (United States)

    Davison, Elizabeth

    2014-03-01

    Applications of graph theory to neuroscience have resulted in significant progress towards a mechanistic understanding of the brain. Functional network representation of the brain has linked efficient network structure to psychometric intelligence and altered configurations with disease. Dynamic graphs provide us with tools to further study integral properties of the brain; specifically, the mathematical convention of hyperedges has allowed us to study the brain's cross-linked structure. Hyperedges capture the changes in network structure by identifying groups of brain regions with correlation patterns that change cohesively through time. We performed a hyperedge analysis on functional MRI data from 86 subjects and explored the cohesive evolution properties of their functional brain networks as they performed a series of tasks. Our results establish the hypergraph as a useful measure in understanding functional brain dynamics over tasks and reveal characteristic differences in the co-evolution structure of task-specific networks.

  8. A consistent partly cracked XFEM element for cohesive crack growth

    DEFF Research Database (Denmark)

    Asferg, Jesper L.; Poulsen, Peter Noe; Nielsen, Leif Otto

    2007-01-01

    Present extended finite element method (XFEM) elements for cohesive crack growth may often not be able to model equal stresses on both sides of the discontinuity when acting as a crack-tip element. The authors have developed a new partly cracked XFEM element for cohesive crack growth with extra...... was used to solve the non-linear equations. The performance of the element is illustrated by modelling fracture mechanical benchmark tests. Investigations were carried out on the performance of the element for different crack lengths within one element. The results are compared with previously...... enrichments to the cracked elements. The extra enrichments are element side local and were developed by superposition of the standard nodal shape functions for the element and standard nodal shape functions for a sub-triangle of the cracked element. With the extra enrichments, the crack-tip element becomes...

  9. Wave-induced pore water pressure in marine cohesive soils

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Cyclic triaxial tests and numerical analyses were undertaken, in order to evaluate the wave-induced pore water pressure in seabed sediments in the Hangzhou Bay. The cyclic triaxial tests indicate that the rate of pore water pressure generation in cohesive soils decreases with time, and the development of the pore water pressure can be represented by a hyperbolic curve. Numerical analyses, taking into account the generation and dissipation of pore water pressure simultaneously, suggest that the pore water pressure buildup in cohesive soils may increase with time continuously until the pore water pressure ratio approaches to 1, or it may decrease after a certain time, which is controlled by drain conditions. These phenomena are different from those in sands. For waves with a return period of 100 a in the Hangzhou Bay, ifthe wave duration is more than 60 h, then the pore water pressure ratio will be close to 1 and soil fabric failure will take place.

  10. Family Change and Implications for Family Solidarity and Social Cohesion

    Directory of Open Access Journals (Sweden)

    Ravanera, Zenaida

    2008-01-01

    Full Text Available EnglishSocial cohesion can be viewed in terms of common projects and networks of social relations that characterize families, communities and society. In the past decades, the basis for family cohesion has shifted from organic to mechanical or from breadwinner to collaborative model. As in many Western countries, data on family change in Canada point to a greater flexibility in the entry and exit from relationships, a delay in the timing of family events, and a diversity of family forms. After looking at changes in families and in the family setting of individuals, the paper considers both intra-family cohesion and families as basis for social cohesion. Implications are raised for adults, children and publicp olicy.FrenchLa cohésion sociale peut se voir à travers les projets communs et les réseaux desrelations sociales qui caractérisent les familles, les communautés et les sociétés.La base de cohésion familiale est passée d’organique à mécanique, pour utiliserles termes de Durkheim, ou vers un modèle de collaboration plutôt qu’unepartage asymétrique de tâches. Comme dans d’autres sociétés orientales, lafamille au Canada est devenue plus flexible par rapport aux entrées et sortiesd’unions, il y a un délais dans les événements familiaux, et une variété deformes de familles. Après un regard sur les changements dans les familles etdans la situation familiale des individus, nous considérons la cohésion intrafamilialeet la famille comme base de cohésion sociale. Nous discutons desimpacts sur les adultes, les enfants et la politique publique.

  11. Long fibre composite modelling using cohesive user’s element

    Czech Academy of Sciences Publication Activity Database

    Kozák, Vladislav; Chlup, Zdeněk

    Melville : American Institute of Physics, 2010 - (Simos, T.), s. 621-624 ISBN 978-0-7354-0831-9. - (AIP Conference Proceedings. Vol. 1281). [ICNAAM 2010 : International Conference on Numerical Analysis and Applied Mathematics 2010 /8./. Rhodes (GR), 19.09.2010-25.09.2010] R&D Projects: GA ČR GA101/08/1304 Institutional research plan: CEZ:AV0Z20410507 Keywords : cohesive element * long fibre composites * FEM Subject RIV: JI - Composite Materials

  12. Health and social cohesion: why care about income inequality?

    OpenAIRE

    Kawachi, I; Kennedy, B P

    1997-01-01

    Throughout the world, wealth and income are becoming more concentrated. Growing evidence suggests that the distribution of income-in addition to the absolute standard of living enjoyed by the poor-is a key determinant of population health. A large gap between rich people and poor people leads to higher mortality through the breakdown of social cohesion. The recent surge in income inequality in many countries has been accompanied by a marked increase in the residential concentration of poverty...

  13. Interlamellar cohesion after corneal crosslinking using riboflavin and UVA

    OpenAIRE

    Wollensak, Gregor; Spörl, Eberhard; Mazzotta, Cosimo; Kalinski, Thomas; Sel, Saadettin

    2011-01-01

    Abstract ABSTRACT Aims: Collagen crosslinking (CXL) treatment of progressive keratoconus using the photosensitizer riboflavin and UVA light of 370 nm wavelength has been shown to increase significantly the tensile strength of corneal collagen by about 300%. In keratoconus, interlamellar and interfibrillar slippage have been proposed as pathogenetic mechanism. Therefore, the aim of this study was to assess the impact of CXL on the interlamellar cohesive force. Methods: 72 po...

  14. Regulation of cohesion-dependent cell interactions in Myxococcus xanthus.

    OpenAIRE

    Dana, J R; Shimkets, L J

    1993-01-01

    Myxococcus xanthus has two nearly independent genetic systems, A and S, which appear to mediate adventurous (single-cell) movement and social (group) movement, respectively. In addition to a notable reduction in group movement, social motility mutants exhibit decreased biofilm formation, cell cohesion, dye binding, fibril production, and fruiting body formation. The stk-1907 allele, containing transposon Tn5 insertion omega DK1907, was introduced into wild-type cells and many social motility ...

  15. Determination of flow-regime boundaries for cohesive particles

    Science.gov (United States)

    Knowlton, T. M.; Findlay, J. G.; Arastoopour, H.; Gidaspow, D.

    1992-10-01

    Cohesive particles (Geldart Group C powders) are fine particles generally less than 30 microns in size. Interparticle forces are large relative to inertial forces in these particles, and cause clumping, sticking, and channeling when attempts are made to fluidize them. These solids do not flow easily through pipes, and bridge extremely easily. The objectives of the work in this program were (1) to develop a hydrodynamic model which can be applied to cohesive solids, and (2) to obtain data in a large-scale (30-cm-diameter) riser to test the model. The work was divided into six tasks: Task 1. Preparation of a Project Work Plan; Task 2. Hydrodynamic Model Development; Task 3. Determination of Rheological Properties for Incorporation into the Model; Task 4. Small-Scale Flow Tests; Task 5. Large-Scale Flow Tests; and Task 6. Comparison of Model With Data. The work was conducted by the Institute of Gas Technology (IGT) in collaboration with the Illinois Institute of Technology (IIT). This work combined the expertise of IIT in model development, with the large-scale experimental capabilities of IGT. IIT researchers developed the hydrodynamic model in the program, while the large-scale data were generated by IGT. Following the preparation of the Project Work Plan in Task 1, work was started on the development of a two-dimensional hydrodynamic model to enable the behavior of cohesive solids in a dilute-phase riser to be simulated. In Task 2, two hydrodynamic models were developed based on the kinetic theory model of granular flow. The models were used to predict data presented in the literature, as well as data generated in Task 5 of this study. In Task 3, rheological data on cohesive oil shale with an average particle size of approximately 12 microns was obtained using a unique device called a cohetester.

  16. The Effect of HRM Quality on Trust and Team Cohesion

    OpenAIRE

    Igor Ivašković

    2014-01-01

    The purpose of this study was to examine the relationships between the perceived quality of HRM, trust among athletes, their trust in head coach, and the perceived team cohesion in the context of basketball teams from four South East European countries. First, the modified version of HRM quality scale was verified on one sample of 277 athletes from 36 clubs. Then the model was developed with the theoretical fundamentals of social exchange theory and tested on data from other sample of 282 ath...

  17. Effect of water temperature on cohesive soil erosion

    OpenAIRE

    Parks, Olivia Waverly

    2013-01-01

    In light of increased stream temperatures due to urbanization and climate change, theeffect of water temperature on cohesive soil erosion should be explored. The objectives of this study are to: determine the effect of water temperature on the erosion rates of clay; determine how erosion rates vary with clay mineralogy; and, explore the relationship between zeta potential and erosion rate. Samples of kaolinite- and montmorillonite-sand mixtures, and vermiculite-dominated soil were placed in t...

  18. An improved cohesive zone model for ductile dynamic crack propagation

    OpenAIRE

    Sagimon Buch, Marc

    2008-01-01

    Ductile dynamic crack propagation is a current field of research in aerospace industry. The damage created by an explosion in a flying airplane depends on the fracture behaviour of the fuselage materials. Thus the rate of fracture for aluminium 2024 T3 is being studied. Analytical and empirical calculation methods do not predict correctly the experimental fracture velocity. Numerical simulations using cohesive elements with standard material models do not estimate it correctly ...

  19. Territorial Cohesion in the Context of Interregional and Transnational Cooperation

    OpenAIRE

    Stein, Axel

    2010-01-01

    This paper draws on experience from the Interreg IIIC project ProgreSDEC, covering local and regional authorities from Greece, Italy, and Spain cooperating with each other in interregional and transnational projects. It looks both at the vertical and horizontal dimensions of European integration and explains three aspects of territorial cohesion. Talking about growing awareness, it should be differentiated between awareness relating to European issues - such as the European territorial and in...

  20. Interpreting Cohesive Forms in the Context of Discourse Inference

    OpenAIRE

    Kehler, Andrew

    1995-01-01

    In this thesis, we present analyses and algorithms for resolving a variety of cohesive phenomena in natural language, including VP-ellipsis, gapping, event reference, tense, and pronominal reference. Past work has attempted to explain the complicated behavior of these expressions with theories that operate within a single module of language processing. We argue that such approaches cannot be maintained; in particular, the data we present strongly suggest that the nature of the coherence relat...

  1. European Agenda for Research on Cities and Social Cohesion

    OpenAIRE

    2011-01-01

    One of the main goals of the Social Polis platform has been the production of a European Research Agenda on “Cities and Social Cohesion”. We believe research on Social Cohesion and Cities is crucial for tackling complex societal problems. We are also convinced that these problems should be addressed by approaching them from different perspectives. The failure of existing integrative mechanisms and the deepening of processes of differentiation and individualization in contempora...

  2. Closing the Gap: Territorial Cohesion through Polycentric Development

    OpenAIRE

    Meijers, E.J.; Waterhout, B.; Zonneveld, W.A.M.

    2007-01-01

    This article discusses and analyses national polycentric development policies aiming at cohesion. Due to its insertion in the 1999 European Spatial Development Perspective ‘polycentricity’ has become an important concept in discussions on Europe’s territorial and economic development. Its content remains however rather unclear. This paper contributes to the discussion on the meaning of polycentricity by looking at national polycentric development policies. These policies can be distinguished ...

  3. Effect of chlorophyllin on induction of exchanges in sister chromatids by gamma irradiation in mice spermatogonia in vivo

    International Nuclear Information System (INIS)

    Mouse were exposed to different doses of gamma radiation and the effect on Sister Chromatid Exchange (SCE) frequency in spermatogonias was evaluated. The effect was analyzed before and after Bromodeoxyuridine (BrdU) incorporation to determine the interference of such agent with the cellular response induced by radiation. The capacity of chlorophyllin (sodium and Copper salt derivative from chlorophyll) to reduce SCE induction by radiation in normal and BrdU radio sensitized spermatogonia was also determined. The results indicate that there was a significant increase in SCE frequency by gamma radiation exposure in these cells, such effect was higher irradiating after BrdU incorporation than before. This fact confirms previous observations that BrdU sensitizes some cells to SCE induction. With regard to the chlorophyllin effect, it was determined that this salt acts as a radioprotector reducing gamma-rays induced SCE before or after BrdU incorporation Total protection was obtained with 200 μg of chlorophyllin per g of body weight in both protocols. Under the experimental conditions this study there was no evidence of genotoxicity induced by chlorophyllin itself. The results suggest that this agent may act as a radioprotector by scavenging free radicals produced by gamma-radiation which cause DNA lesions that are involved in SCE formation. (Author)

  4. Inhibition of UV-induced sister chromatid exchanges in ICR 2A frog cells by pretreatment with γ-rays

    International Nuclear Information System (INIS)

    Exposure of ICR 2A frog cells to UV induced the formation of sister chromatid exchanges (SCEs). However, pretreatment of UV-irradiated cells with γ-rays resulted in a reduction in the level of SCEs, confirming the prediction made by the replication model for SCE induction. This effect was observed over a range of UV fluences (1-5 J/m/sup 2/) and γ-ray doses (50-500 rad). The depression in the yield of SCEs was greatest when the cells were UV-irradiated either immediately or 3 h after γ-irradiation. Following a 6 h incubation, the reduction was much less pronounced while at 48 h the level of SCEs was nearly identical to that of cells exposed to UV alone. This corresponds roughly to the kinetics of depression and recovery in DNA synthesis after γ-irradiation of ICR 2A cells. Hence, these results support the hypothesis that the depression of UV-induced SCEs was the result of a delay in replicon initiation caused by //i/-irradiation

  5. Sister chromatid exchanges and micronuclei in lymphocytes of operating room personnel occupationally exposed to enfluorane and nitrous oxide.

    Science.gov (United States)

    Pasquini, R; Scassellati-Sforzolini, G; Fatigoni, C; Marcarelli, M; Monarca, S; Donato, F; Cencetti, S; Cerami, F M

    2001-01-01

    The objective of this article is to assess whether occupational exposure to anesthetics increases genotoxic risk. We investigated two cytogenetic biomarkers, sister chromatid exchanges (SCE) and micronuclei (MN), in the peripheral blood lymphocytes of 46 anesthesiologists (24 men), working in operating rooms and mostly exposed to enfluorane and nitrous oxide, and 66 controls (35 men), not exposed to chemicals and living in the same area. Contrary to what was expected, a lower frequency of SCE was found in male anesthesiologists than in controls. Smoking status was found to be positively associated with SCE frequency in each group, while no relation to age was evident. On the contrary, MN frequency was significantly higher in female, but not male, anesthesiologists than in controls. Age and smoking status did not modify the association. No relationship between MN frequency and duration of employment was found in anesthesiologists. Smoking status and mean number of cigarettes smoked per day in smokers were not associated with MN frequency in either anesthesiologists or in controls. MN analysis seems to be a sensitive index of possible genotoxic effects of occupational exposure to anesthesiologists, and women appear to be more susceptible to these effects than men. PMID:11394710

  6. Hypersensitivity to mutation and sister-chromatid-exchange induction in CHO cell mutants defective in incising DNA containing UV lesions

    International Nuclear Information System (INIS)

    Five UV-sensitive mutant strains of CHO cells representing different genetic complementation groups were analyzed for their ability to perform the incision step of nucleotide excision repair after UV exposure. The assay utilized inhibitors of DNA synthesis to accumulate the short-lived strand breaks resulting from repair incisions. After 6 J/m2, each of the mutants showed 2, the rate in AA8 was similar to that at 6 J/m2, but the rates in the mutants were significantly higher (approx. 20% of the rate of AA8). Thus by this incision assay the mutants were phenotypically indistinguishable. Each of the mutants were hypersensitive to mutation induction at both the hprt and aprt loci by a factor of 10, and in the one strain tested ouabain resistance was induced sevenfold more efficiently than in AA8 cells. Sister chromatid exchange was also induced with sevenfold increased efficiency in the two mutant strains examined. Thus, here CHO mutants resemble xeroderma pigmentosum cells in terms of their incision defects and their hypersensitivity to DNA damage by UV

  7. The chromosome damage induced by x-ray radiation doses. Comparison between dicentric chromosomes, micronuclei and Sister Chromatid Exchanges analyses

    International Nuclear Information System (INIS)

    Exposure to ionizing radiations is a well-known source of chromosome damage. Here we present a comparison among three different methodologies employed to recognize cytogenetic damage, after an acute exposure of human lymphocytes to 3 Gy of X-rays (100kVp). Scoring of dicentric chromosomes, present in first mitosis ''in vitro'', was the method of preference as dicentrics increased 937.5 times with respect to background. Micronucleus scoring in binucleated-cytokinesis blocked cells showed an increase of 32.5 times, while it was only of 1.46 times when Sister Chromatid Exchanges (SCEs) were analyzed. The estimated probability of an acentric fragment becoming a micronucleus was around 0.25. Intercellular distribution of dicentrics agree with Poisson, while micronucleus were overdispersed. When analyzed at second cycle after damage induction, the dicentrics yield as well as the level of cells with unstable cromosome aberrations, decreased around a half. Finally, SCEs level was similar in cells with or without unstable structural chromosome aberrations. (Author)

  8. Effects of hyperthermia and x irradiation on sister chromatid exchange (SCE) frequency in Chinese hamster ovary (CHO) cells

    International Nuclear Information System (INIS)

    The BrdUrd labeling method was used to evaluate the effects of hyperthermia, x irradiation, and the combined treatment on the incidence of sister chromatid exchange (SCE) in Chinese hamster ovary (CHO) cells. Cells cultured in McCoy's 5A media containing 10 μM 5-bromodeoxyuridine were synchronized after one cell cycle by mitotic shake-off. Early-G1 cells were heated by submerging culture flasks in a 44 +- 0.050C water bath for periods of 20, 40, and 60 min. By the same method, other cultures were x irradiated at doses of 100, 200, 400, and 600 rad. A third protocol involved combined treatment of 20 min at 440C followed immediately by one of the above radiation doses. A fourth protocol reversed the sequence of the combined treatment applying x irradiation (200 or 400 rad) followed immediately by hyperthermia. The data showed that hyperthermia and x irradiation both elevated the frequency of SCEs significantly whether applied separately or together. The combined treatment (heat: 20 min at 440C plus varying x-radiation doses) produced results suggestive of a synergistic interaction. The sequence of the heat and x irradiation did not appear to have a significant effect on the production of SCE

  9. Elastatinal and leupeptin: effects on u.v.-induced mutation and sister-chromatid exchanges in Chinese hamster cells

    International Nuclear Information System (INIS)

    Microbial protease inhibitors elastatinal and leupeptin were tested for cytotoxicity and for effects on spontaneous and u.v.-induced 6-thioguanine-resistant (6TGr) mutation and sister-chromatid exchange (SCE) in V79 Chinese hamster cells. Continuous treatment with elastatinal exhibited marked cytotoxicity, while leupeptin was almost non-cytotoxic. Elastatinal rapidly induced cytotoxic effects as a function of its concentration and time of exposure. Near maximum cytotoxicity was reached after exposure of 6-8 h and this was partially abolished by the presence of 2.5 micrograms cycloheximide per ml. Concentrations of either protease inhibitor which gave 60-80% survival had no appreciable effects on u.v. survival and frequencies of spontaneous and u.v.-induced 6TGr mutation and SCE. However, reconstruction experiments revealed that pretreatments of 6TGr and 6TGs (wild-type) cells with these inhibitors for 6 days tended to block metabolic co-operation in their co-cultures. Thus, elastatinal and leupeptin are neither clastogenic mutagenic by themselves, and do not alter mutation fixation and expression

  10. The use of the differential staining of sister chromatids in the study of the cytogenetic radiation effects in human lymphocytes

    International Nuclear Information System (INIS)

    Differential staining of sister chromatides is performed, cells of the 1-st and the following mitoses are identified, chromosome aberrations are accounted, and statistic processing of data is performed. Venous blood of healthy donors is used as material for analysis. It is irradiated in flasks by 60Co gamma-quanta in the doses of 1, 1.5, 2, 3, 4, 5, 6, and 8 Gy. Lymphocytes of the peripheral blood are cultivated at 37 deg C in the medium containing antibiotics, phytohemaggluninin and 5-bromiurnedeoxyidine (BDU). The observed distributions of dicentrics in cells are compared with theoretic Poisson distribution. The dependence of frequency of dicentrics on radiation dose is studied by the method of regressive analysis. The importance of applying this technique in radiation cytogenetic investigations to increase the accuracy of chromosome aberration account in stimulated phytohemagglutinin cultures of lymphocytes of human peripheral blood and to study regularities of their elimination after cells pass the 1-st and the second mitoses, is shown

  11. Experimental identification of cohesive zone models from thermomechanical imaging techniques

    International Nuclear Information System (INIS)

    This work deals with the identification of cohesive zone models. These models were initially proposed in the 1960's. They are now more and more frequently used in numerical simulations to account for crack initiation and propagation in different materials and structures. The identification of these models still remains a delicate issue. The recent developments in imaging techniques now allow reaching local measurement fields (e.g. strain, temperature,..). We propose here to use the large amount of information given by these techniques to set up an identification procedure accounting for either the localization development (structural effect) and also the character of the different irreversibility sources encountered (thermomechanical behavior). We study damageable elasto-plastic ductile materials. Damage is associated to a cohesive behavior of the interface between volumic elements supposed to remain purely elasto-plastic. The identification procedure involves two steps. The first one consists in characterizing the shape and the parameters of the cohesive zone on tensile tests by analyzing the mechanical fields locally developed. The second one consists in checking the thermo-mechanical consistency of the identified model by confronting the calorimetric measurements deduced from temperature fields with the previsions of the identified model. This method is applied on different materials (Dual Phase steel and copper). A specific caution is conferred to the characterization of the characteristic length necessarily introduced by the identification. It is shown that this length can be estimated regarding the different parameters introduced in the image processing. (author)

  12. Direct Tension Test Using a Plate Specimen in Cohesive Soil

    Science.gov (United States)

    Nishimura, Shin-Ichi

    Hydraulic fracturing is probably one of the causes of leakage and collapse in a dam body or foundation. Water pressure develops cracks and this is one of the causes for hydraulic fracturing. It is important to evaluate characteristics of tensile strength in the foundation and embankment material of fill-dam to examine development conditions of the cracks. It is possible to evaluate tensile strength of hard rocks and metals by fixing both ends of the specimen with chucks and making it work directly. However, it is not possible to use the same method for soft material like cohesive soil. Hence direct tensile test was performed in this research by the plate type specimen used for the calculation of energy release rate (J integral). Then the stress distribution in the specimen and the energy release rate were calculated by FEM to examine a form of the specimen useful for the direct tensile test of cohesive soil. Consequently it is considered that tensile strength of cohesive soil can be measured by adjusting height of the specimen and length of the initial crack to a suitable value respectively.

  13. The Process Architecture of EU Territorial Cohesion Policy

    Directory of Open Access Journals (Sweden)

    Andreas Faludi

    2010-08-01

    Full Text Available When preparing the European Spatial Development Perspective (ESDP, Member States were supported by the European Commission but denied the EU a competence in the matter. Currently, the Treaty of Lisbon identifies territorial cohesion as a competence shared between the Union and the Member States. This paper is about the process architecture of territorial cohesion policy. In the past, this architecture resembled the Open Method of Coordination (OMC which the White Paper on European Governance praised, but only in areas where there was no EU competence. This reflected zero-sum thinking which may continue even under the Lisbon Treaty. After all, for as long as territorial cohesion was not a competence, voluntary cooperation as practiced in the ESDP process was pursued in this way. However, the practice of EU policies, even in areas where there is an EU competence, often exhibits features of the OMC. Surprisingly effective innovations hold the promise of rendering institutions of decision making comprehensible and democratically accountable. In the EU as a functioning polity decision making is thus at least part deliberative so that actors’ preferences are transformed by the force of the better argument. This brings into focus the socialisation of the deliberators into epistemic communities. Largely an informal process, this is reminiscent of European spatial planning having been characterised as a learning process.

  14. EU COHESION POLICY NEEDS DIFFERENTIATED POLICY MIX ADEQUATE TO SPECIFICS OF ECONOMIC REGIONS

    Directory of Open Access Journals (Sweden)

    Gheorghe ZAMAN

    2008-06-01

    Full Text Available The 2007-2013 programming period of the EU focuses on economic and social cohesion via three fundamental objectives: convergence – competitiveness and employment – European territorial co-operation. The horizontal dimension of cohesion policy refers to diminishing the regional disparities and solidarity with the lagging regions’ population. Considering the big regional disparities in the New Member States (NMS as well as the gap between their GDP per capita at national level and the EU average, these countries are the main beneficiary of the EU financial allocations, especially via convergence objective. However, two interrelated questions are entailed by this issue. One of them refers to the capacity of these countries to absorb effectively the EU funds. The other one concentrates on the impact of the absorbed EU funds, in other words to the qualitative aspects of the absorption capacity. Our paper discusses these aspects mainly from the viewpoint of regional disparities in the NMS, proposing a typology of their regions based on the main regional growth characteristics. The implications of the structural assistance on regional disparities are also addressed, taking into consideration economic and social criteria and requirements at EU, national, regional and local levels.

  15. Study on the impact of the single market on cohesion: implications for cohesion policy, growth and competitiveness

    OpenAIRE

    LSE Enterprise,

    2011-01-01

    This study was prepared by LSE Enterprise, drawing on work by the Centre for Social and Economic Research (CASE), the University of Helsinki, and Vienna University of Economics and Business. It assessed the impact of the Single Market on growth, competitiveness and employment in EU27, in particular as regards its role in generating disparities and convergence processes. It also analysed the institutional and policy linkages between cohesion policy, the Lisbon process and the Europe 2020 s...

  16. Cell-cycle regulation of cohesin stability along fission yeast chromosomes

    OpenAIRE

    Bernard, Pascal; Schmidt, Christine Katrin; Vaur, Sabine; Dheur, Sonia; Drogat, Julie; Genier, Sylvie; Ekwall, Karl; Uhlmann, Frank; Javerzat, Jean-Paul

    2007-01-01

    Sister chromatid cohesion is mediated by cohesin, but the process of cohesion establishment during S-phase is still enigmatic. In mammalian cells, cohesin binding to chromatin is dynamic in G1, but becomes stabilized during S-phase. Whether the regulation of cohesin stability is integral to the process of cohesion establishment is unknown. Here, we provide evidence that fission yeast cohesin also displays dynamic behavior. Cohesin association with G1 chromosomes requires continued activity of...

  17. Modeling reciprocal team cohesion-performance relationships, as impacted by shared leadership and members' competence.

    Science.gov (United States)

    Mathieu, John E; Kukenberger, Michael R; D'Innocenzo, Lauren; Reilly, Greg

    2015-05-01

    Despite the lengthy history of team cohesion-performance research, little is known about their reciprocal relationships over time. Using meta-analysis, we synthesize findings from 17 CLP design studies, and analyze their results using SEM. Results support that team cohesion and performance are related reciprocally with each other over time. We then used longitudinal data from 205 members of 57 student teams who competed in a complex business simulation over 10 weeks, to test: (a) whether team cohesion and performance were related reciprocally over multiple time periods, (b) the relative magnitude of those relationships, and (c) whether they were stable over time. We also considered the influence of team members' academic competence and degree of shared leadership on these dynamics. As anticipated, cohesion and performance were related positively, and reciprocally, over time. However, the cohesion → performance relationship was significantly higher than the performance → cohesion relationship. Moreover, the cohesion → performance relationship grew stronger over time whereas the performance → cohesion relationship remained fairly consistent over time. As expected, shared leadership related positively to team cohesion but not directly to their performance; whereas average team member academic competence related positively to team performance but was unrelated to team cohesion. Finally, we conducted and report a replication using a second sample of students competing in a business simulation. Our earlier substantive relationships were mostly replicated, and we illustrated the dynamic temporal properties of shared leadership. We discuss these findings in terms of theoretical importance, applied implications, and directions for future research. PMID:25751749

  18. Relationship of the demethylation of the DNA with the induction of the sister chromatid exchanges (SCE) In vivo

    International Nuclear Information System (INIS)

    The methylation of the DNA is an epigenetic modification that has an important paper in the regulation of the functionality of the genome of the organisms. It can be altered by demethylation processes, either natural or experimentally induced. The 5-azacytidine (Aza) is a compound that causes the demethylation of the DNA (dm-DNA), inducing with it, expression genic and increase in the frequency of the Sister Chromatid Exchange (SCE). The SCE is a genotoxicity indicator, caused by diverse mutagens and carcinogen. Since the biological meaning and the formation mechanism of this phenomenon has not been totally illustrious, the exploration of the relation between the dm-DNA and the induction of SCE, it could offer new knowledge to explain those queries. The purpose of this work was to study in cells of the mouse bone marrow In vivo, the effect of the Aza on the induction of SCE, based on two aspects: 1) dose answer and 2) the effectiveness of multiple exhibition. To six groups of three to five animals, they are administered Aza to dose of 5, 10, 15 or 20 mg/Kg of weight; in sharp or multiple form, previously to the bromodeoxyuridine supply and 24 h was sacrificed after this; 2 h after an injection with colchicine. Preparations of those metaphases were made, those which were dyed by means of a technique of fluorescence more Giemsa. It was observed that to sharp low dose, the Aza produced an increment in the frequency of SCE that although small it was proportional and statistically significant. To sharp and multiple high doses, the Aza doesn't cause additional increments of SCE, but if toxicity at cellular level and of individuals. It is concluded that a relationship exists between the dm-DNA and the induction of SCE. It is suggested that the total demethylation of the DNA causes 2 SCE/Cell in cells of the mouse bone marrow, or that the cytotoxicity prevents to evidence a bigger induction. (Author)

  19. Sister chromatid exchanges in the bone marrow cells of in vivo rats induced by gamma radiation and chemical mutagens

    International Nuclear Information System (INIS)

    Sister chromatid exchanges (SCE) in the bone marrow of in vivo rats induced by gamma radiation doses and by the chemical mutagens, mitomycin C (MMC), cyclophosphamide (CP), and sulphonate-methylmethane (SMM), were studied. The purpose was to evaluate the sensitivity and reproducibility of a simplified SCE in vivo detecting system developed in our laboratory and to compare the results obtained with those reported elsewhere. Simplification consisted in administering the amounts of 5-bromo-2'-deoxyuridine (BrdU) necessary to observe the SCE, after first adsorbing the BrdU in activated carbon and then injecting it interperitoneally, into the rats. The results were a longer time in vivo ADN incorporation without convulsions in the rats, and a reduction in the time course as compared to other methods. We observed a basal rate of 3.6+-0.37 SCE/cell and that: 0.44 Gy of gamma radiation induced 7.7+-0.73 SCE/cell; 1.6 μg/g of MMC induced 8.1+-1.20 SCE/cell; 5 μg/g of CP induced 8.25+-1.5 SCE/cell, 40 μg/g of SMM induced 22.0+-5 SCE/cell and 380 μg/g of sulphonate-ethylmethane induced 8.6+-1.2 SCE/cell. This showed that all the agents were capable of inducing SCE in the bone marrow cells of rats in vivo under our conditions. We noted a greater induced efficiency for gamma radiation than the obtained by other investigators and a relatively similar efficiency in the case of chemical mutagens as reported in other studies. (author)

  20. Evaluation of radioprotection properties of propolis by chromosomal alterations, cell proliferation kinetics, mitotic index and sister chromatid exchange

    International Nuclear Information System (INIS)

    A consequence of ionizing radiation is the induction of chromosomal alterations. This causality relation involves that chromosomal alterations can be considered a good indicator of the radiological damage. Some chemical agents can modulate the tissue response to radiation. These compounds are useful because they show certain selectivity, protecting the healthy tissues (radioprotectors) or increasing the sensibility of tissues to radiations (radiosensibilizators). Propolis substance has showed radioprotection properties which are performed in the following study. Propolis is a product of extraordinary interest for both medicine and pharmaceutical industry, since it is assumed to show diverse beneficial health effects. Among many other attributes of EEP (propolis ethanolic extract), it exhibits antioxidant and radical free scavenger properties. In a previous study, human peripheral blood lymphocytes were exposed to 2 Gy of γ rays in presence and absence of EEP, and the analysis showed a reduction in the frequency of dicentrics and rings, with a maximum protection of 50%. The proposed concentration for radioprotection would be between 120-500 μg.ml-1. The cytotoxic effect has been evaluated analyzing the EEP effect in the cellular division cycle. Propolis ethanolic extract (EEP) has been obtained and samples of peripheral blood have been cultured in the presence of increasing concentrations of EEP. In order to quantify it, two indexes have been used, the mitotic index and cell proliferation index. For both indexes the cytotoxic effect takes place from 750 μg.ml-1 concentrations onwards. Similar results were obtained for the analysis of chromosomal aberrations. Finally, propolis effect in lymphocytes by sister chromatid exchange test has been presented for higher concentrations of EEP. (author)

  1. Variation in sister chromatid exchange frequencies between human and pig whole blood, plasma leukocyte, and mononuclear leukocyte cultures

    International Nuclear Information System (INIS)

    Sister chromatid exchange (SCE) induction by ultraviolet (UV) light was studied in both human and pig whole blood cultures (WBC) and plasma leukocyte cultures (PLC). No variation in SCE frequency was observed between pig WBC and PLC in control as well as in treated cells. Conversely, SCE frequencies of human PLC were consistently higher than those of WBC in control and UV-exposed cells. Thus, red blood cells (RBCs) do not influence the sensitivity of lymphocytes to UV LIGHT exposure, and there must be some different culture condition(s) in the inducation of SCEs between human WBC and PLC but not in swine lymphocyte cultures. Since the BrdUrd/lymphocyte ratio of WBC was halved in PLC, the effect of BrdUrd concentration in inducing the SCE baseline frequency of PLC may be ruled out. Neither the cell separation technique nor polymorphonuclear leukocytes had a significant role in the elevated SCE frequency of human PLC or MLC. Experiments where human RBCs were titrated into human PLC showed that the induction of an elevated SCE frequency of PLC was suppressed in a dose-dependent manner by the presence of RBCs in the culture medium. Since the incorporation of pig or human RBCs into human PLC as well as into MLC reduced the SCE frequency to that of WBC, a common component and/or function existing in these cells is suggested. Analysis of different RBC components showed that RBCs, specifically RBC ghosts, release a diffusible but not dialyzable corrective factor into culture medium that is able to reduce the SCE frequencies of PLC

  2. Low doses of alpha particles do not induce sister chromatid exchanges in bystander Chinese hamster cells defective in homologous recombination

    Energy Technology Data Exchange (ETDEWEB)

    Nagasawa, H; Wilson, P F; Chen, D J; Thompson, L H; Bedford, J S; Little, J B

    2007-10-26

    We reported previously that the homologous recombinational repair (HRR)-deficient Chinese hamster mutant cell line irs3 (deficient in the Rad51 paralog Rad51C) showed only a 50% spontaneous frequency of sister chromatid exchange (SCE) as compared to parental wild-type V79 cells. Furthermore, when irradiated with very low doses of alpha particles, SCEs were not induced in irs3 cells, as compared to a prominent bystander effect observed in V79 cells (Nagasawa et al., Radiat. Res. 164, 141-147, 2005). In the present study, we examined additional Chinese hamster cell lines deficient in the Rad51 paralogs Rad51C, Rad51D, Xrcc2, and Xrcc3 as well as another essential HRR protein, Brca2. Spontaneous SCE frequencies in non-irradiated wild-type cell lines CHO, AA8 and V79 were 0.33 SCE/chromosome, whereas two Rad51C-deficient cell lines showed only 0.16 SCE/chromosome. Spontaneous SCE frequencies in cell lines defective in Rad51D, Xrcc2, Xrcc3, and Brca2 ranged from 0.23-0.33 SCE/chromosome, 0-30% lower than wild-type cells. SCEs were induced significantly 20-50% above spontaneous levels in wild-type cells exposed to a mean dose of 1.3 mGy of alpha particles (<1% of nuclei traversed by an alpha particle). However, induction of SCEs above spontaneous levels was minimal or absent after {alpha}-particle irradiation in all of the HRR-deficient cell lines. These data suggest that Brca2 and the Rad51 paralogs contribute to DNA damage repair processes induced in bystander cells (presumably oxidative damage repair in S-phase cells) following irradiation with very low doses of alpha particles.

  3. Cohesive zone length of metagabbro at supershear rupture velocity

    Science.gov (United States)

    Fukuyama, Eiichi; Xu, Shiqing; Yamashita, Futoshi; Mizoguchi, Kazuo

    2016-06-01

    We investigated the shear strain field ahead of a supershear rupture. The strain array data along the sliding fault surfaces were obtained during the large-scale biaxial friction experiments at the National Research Institute for Earth Science and Disaster Resilience. These friction experiments were done using a pair of meter-scale metagabbro rock specimens whose simulated fault area was 1.5 m × 0.1 m. A 2.6-MPa normal stress was applied with loading velocity of 0.1 mm/s. Near-fault strain was measured by 32 two-component semiconductor strain gauges installed at an interval of 50 mm and 10 mm off the fault and recorded at an interval of 1 MHz. Many stick-slip events were observed in the experiments. We chose ten unilateral rupture events that propagated with supershear rupture velocity without preceding foreshocks. Focusing on the rupture front, stress concentration was observed and sharp stress drop occurred immediately inside the ruptured area. The temporal variation of strain array data is converted to the spatial variation of strain assuming a constant rupture velocity. We picked up the peak strain and zero-crossing strain locations to measure the cohesive zone length. By compiling the stick-slip event data, the cohesive zone length is about 50 mm although it scattered among the events. We could not see any systematic variation at the location but some dependence on the rupture velocity. The cohesive zone length decreases as the rupture velocity increases, especially larger than √{2} times the shear wave velocity. This feature is consistent with the theoretical prediction.

  4. Investigation of non-cohesive levee breach by overtopping flow

    Institute of Scientific and Technical Information of China (English)

    YU Ming-hui; WEI Hong-yan; LIANG Yan-jie; ZHAO Yong

    2013-01-01

    This paper presents an experimental study of the overtopping breach of homogeneous non-cohesive levee or dike in a 180° bend rectangular flume.Detailed experimental and numerical results provide information on the breach flow discharge and longitudinal and transversal breach profiles for this type of levee.It is indicated that the water level and the flow discharge in the river and the levee material properties are significant influencing factors for the breach evolution.The plane form of the breach is approximately an asymmetrical hyperbola.A formula with a non-constant flow factor is proposed to compute this kind of breach discharge.

  5. Internal character dictates transition dynamics between isolation and cohesive grouping

    Science.gov (United States)

    Manrique, Pedro D.; Hui, Pak Ming; Johnson, Neil F.

    2015-12-01

    We show that accounting for internal character among interacting heterogeneous entities generates rich transition behavior between isolation and cohesive dynamical grouping. Our analytical and numerical calculations reveal different critical points arising for different character-dependent grouping mechanisms. These critical points move in opposite directions as the population's diversity decreases. Our analytical theory may help explain why a particular class of universality is so common in the real world, despite the fundamental differences in the underlying entities. It also correctly predicts the nonmonotonic temporal variation in connectivity observed recently in one such system.

  6. Water Transport through Cohesion-Tension in Porous Structures

    Science.gov (United States)

    Kosaraju, Srinivas

    2015-11-01

    The predominant theory to explain water transport through plant xylem is the cohesion-tension theory. According to the theory, negative pressure is created due to water evaporation through millions of microscopic capillary pores from tree leaves. The negative pressures are large enough to lift water hundreds of feet against gravity. In an attempt to replicate the process, multiple structures with varying porosity are tested to create negative pressures through water evaporation. The negative pressure created is used to support a water column. The current research is aimed to create artificial leaves using porous structures and be able to transport water in high rise buildings using renewable energy sources such as solar power.

  7. The role of Religion in Establishing Social Cohesion

    OpenAIRE

    Hervieu-Léger, Danièle

    2013-01-01

    With the enlargement of the European Union on the agenda, and at a time when there is a manifest need for a “European voice” to make itself heard on the world arena, it seems particularly appropriate to consider the role of religion in establishing social cohesion and creating European identity. The question has been raised explicitly in the current debates as to whether or not the introduction of the future European Constitution should refer to transcendent matters and/or Europe’s religious ...

  8. Multiculturalism and Community Cohesion in Britain: The Case of Arab Minority

    OpenAIRE

    Mohamed Benitto

    2015-01-01

    This article falls within the scope of debate about 'Community Cohesion' in Britain. Community cohesion is at the centre of public policy initiated in response to the urban disturbances in northern towns. Many official reports pointed out that lack of community cohesion is an element jeopardizing security and safe coexistence. In this sense, this article explores hindrances to intergroup coexistence, given that this issue is the main concern in this pluralist society since the attacks in Lond...

  9. Social Cohesion, Social Inequality and Social Participation in India: an Approach from Women’s Perspectives

    OpenAIRE

    Protap Mukherjee

    2012-01-01

    The concept of social cohesion has received great political and research attention at the national and supranational levels in developed countries. At the national level, Canadian Government and at the supranational level, the OECD, the World Bank and European Commission are dealing with the issues of social cohesion (Berger-Schmitt, 2002). The OECD and the World Bank, both have considered the importance of social cohesion factors in economic development and growth (Ritzen et.al., 2000). Chan...

  10. Family Cohesion and its Relationship to Psychological Distress among Latino Groups

    OpenAIRE

    Rivera, Fernando I.; Guarnaccia, Peter J.; Mulvaney-Day, Norah; Lin, Julia Y.; Torres, Maria; Alegria, Margarita

    2008-01-01

    This paper presents analyses of a representative sample of US Latinos (N=2540) to investigate whether family cohesion moderates the effects of cultural conflict on psychological distress. The results for the aggregated Latino group suggests a significant association between family cohesion and lower psychological distress and the combination of strong family cohesion with presence of family cultural conflict was associated with higher psychological distress. However, this association differed...

  11. The effect of group cohesion on rehabilitation outcome in cancer survivors

    OpenAIRE

    May, Anne M; Duivenvoorden, Hugo J.; Korstjens, Irene; van Weert, Ellen; Hoekstra-Weebers, Josette E. H. M.; Van Den Borne, Bart; Mesters, Ilse; van der Schans, Cees P; Ros, Wynand J. G.

    2008-01-01

    Objective: Group-based physical training interventions have been shown to be effective in increasing quality of life in cancer survivors. Until now, however, the impact of cohesion within the group on intervention outcome has not been investigated. Methods: We examined self-reported individual group cohesion ratings collected in the first half of a 12-week rehabilitation programme for cancer survivors (N = 132). Four dimensions of group cohesion were measured, i.e. the bond with the group as ...

  12. Social Cohesion : Theoretical Debates and Practical Applications with Respect to Jobs

    OpenAIRE

    Norton,Andrew; Haan, Arjan

    2012-01-01

    This paper reviews the sociological and related literatures to provide insights regarding social cohesion, including its unpredictability. Apparently some cohesive societies have erupted in violent conflict, and the public systems that one would expect to manage these potential conflicts have at times reinforced them. Simultaneously, some of the “pessimism” of classic sociology about decline of social cohesion, notably in the context of great transformations such as urbanization and industria...

  13. Cities, social cohesion and the environment: towards a future research agenda

    OpenAIRE

    Cook, Ian; Swyngedouw, Erik

    2012-01-01

    It will be argued in this paper that the problematic of social cohesion is also one of socio-ecological cohesion whereby the urbanisation of nature and its socio-environmentally enabling and disabling conditions are key processes. By viewing the contradictions of the urbanisation process as intrinsically socio-ecological ones, the terrain of social cohesion is shifted both epistemologically and politically. The paper critically examines three contemporary schools of thought that consider in d...

  14. An Analysis of Cohesive Devise in an English Text from the Perspective of Discourse Analysis

    Institute of Scientific and Technical Information of China (English)

    石佳

    2014-01-01

    This paper analyzes the cohesion in the text“Three Days to See”from the perspective of discourse analysis. It is ana-lyzed by cohesive devises put forward by Halliday, that is, reference, substitution and ellipsis, conjunction and lexical cohesion. It is found that all those devises have been used in the text, therefore making the text textual or“be a text”.

  15. Can High group cohesion be harmful? A case study of a Junior ice-hockey team

    OpenAIRE

    Rovio, Esa; Eskola, Jari; Kozub, Stephen A; Duda, Joan L.; Lintunen, Taru

    2009-01-01

    High group cohesion is considered to be beneficial and lead to better performance. This qualitative case study describes a case in which high social cohesion led to a deterioration in a team's performance. The aim of the present study was to investigate the relationships between performance in a team sport and social psychological group phenomena such as cohesion, conformity, groupthink, and group polarization. The participants were members of a junior-league ice-hockey team, consisting of th...

  16. Interactive Effects of Team Cohesion on Perceived Efficacy in Semi-Professional Sport

    OpenAIRE

    Francisco Miguel Leo Marcos; Pedro Antonio Sánchez Miguel; David Sánchez Oliva; Tomás García Calvo

    2010-01-01

    The present study examined the relationships among cohesion, self-efficacy, coaches’ perceptions of their players’ efficacy at the individual level and athletes’ perceptions of their teammates’ efficacy. Participants (n = 76) recruited from four semi- professional soccer and basketball teams completed cohesiveness and efficacy questionnaires who. Data were analyzed through a correlational methodology. Results indicated significant correlations between self-efficacy and task cohesion and socia...

  17. An examination of the relationship between athlete leadership and cohesion using social network analysis

    OpenAIRE

    Loughead, Todd M.; Fransen, Katrien; Van Puyenbroeck, Stef; Hoffmann, Matt; Boen, Filip

    2016-01-01

    Two studies investigated the structure of different athlete leadership networks and its relationship to cohesion using Social Network Analysis. In Study 1, we examined the relationship between a general leadership network and measures of task and social cohesion using the Group Environment Questionnaire. In Study 2, we investigated the leadership networks for four different athlete leadership roles (task, motivational, social, and external) and their association with task and social cohesion....

  18. Governance as glue: Urban governance and social cohesion in post-WWII neighbourhoods in the Netherlands

    OpenAIRE

    Dekker, K.K.

    2006-01-01

    At the time when the post-WWII neighbourhoods were built, they were much wanted housing environments. Today, however, they face many problems with safety, concentrations of poverty, and liveability. Much good is expected of social cohesion to restore the situation in these neighbourhoods. Policymakers and researchers alike are eager to understand how social cohesion in urban neighbourhoods can be improved. Simultaneously with the attention for social cohesion we observe a change in the way th...

  19. Social capital or social cohesion: what matters for subjective well-being (SWB)?

    OpenAIRE

    KLEIN Carlo

    2011-01-01

    The theoretical analysis of the concepts of social capital and of social cohesion shows that social capital should be considered as a micro concept whereas social cohesion, being a broader concept than social capital, is a more appropriate concept for macro analysis. Therefore, we suggest that data on the individual level should only be used to analyze the relationship between social capital, social cohesion indicators and subjective well-being and that they do not allow commenting on the lev...

  20. Mesoscopic discrete element modelling of cohesive powders for bulk handling applications

    OpenAIRE

    Thakur, Subhash Chandra

    2014-01-01

    Many powders and particulate solids are stored and handled in large quantities across various industries. These solids often encounter handling and storage difficulties that are caused by the material cohesion. The cohesive strength of a bulk material is a function of its past consolidation stress. For example, high material cohesive strength as a result from high storage stresses in a silo can cause ratholing problems during discharge. Therefore, it is essential to consider th...

  1. The African indigenous churches' spiritual resources for democracy and social cohesion

    OpenAIRE

    Sibusiso T. Masondo

    2014-01-01

    This article outlines resources possessed by the African indigenous churches (AICs) that help them engage with the democratic dispensation and could be used to foster social cohesion in South Africa. It starts off with the premise that social cohesion is that which holds the nation together. The South African rainbow-nation narrative tended to focus on tolerance and there cognition of diversity as strength. Tolerance does not address the fundamental issues that would facilitate cohesion. The ...

  2. Coordinates of the Absorption Capacity of Structural and Cohesion Funds at EU Level

    Directory of Open Access Journals (Sweden)

    Anca Simina POPESCU

    2015-09-01

    Full Text Available The structural and cohesion funds are considered an attractive instrument for the funding of investments opportunities especially in times of crisis when the private investments are reduced. Nevertheless, they have not been factually highlighted in order to empirically document the role of European funds in supporting the short-term economic growth, at macroeconomic level. The target of absorbing as much European financial non-refundable aid requires constant efforts made by the member states and administration authorities, the involvement of regional and local public administrations in each stage of the process, as well as an appropriate capacity of institutional structures and management and control systems, they being basic premises of this objective achievement.

  3. New Territorial Development Tools in the Cohesion Policy 2014-2020

    Directory of Open Access Journals (Sweden)

    Györgyi Nyikos

    2014-12-01

    Full Text Available Nowadays an important question is how to use the limited resources available in the most efficient and sustainable way. The assessment of development policy interventions and the question of successful absorption of development funds shifted clearly towards stronger enforcement of the aspects efficiency and effectiveness. There is clearly a need for an integrated approach to deliver an effective and sustainable response. The question is how the new territorial development tools – established by the new cohesion policy regulation for the coming programming period - can fit in these conditions, how can they help to achieve the common goals and response to the integrated approach. Cooperation and in-depth knowledge is required for stakeholders to make use of the new tools in an integrated manner.

  4. Exchange and cohesion in dyads and triads: A test of Simmel's hypothesis.

    Science.gov (United States)

    Yoon, Jeongkoo; Thye, Shane R; Lawler, Edward J

    2013-11-01

    This paper uses social exchange theory to address a classic question posed by Simmel (1964) regarding dyads and triads. The question is whether exchanges in a triad will generate more cohesion at the group level than exchanges in an isolated dyad. The main hypotheses, integrating several ideas from Simmel and social exchange theories, are as follows. First, triads generate less variability of behavior than dyads; that is, there is more uniformity or convergence in triads. Second, in the context of repeated exchange, we predict higher levels of cohesion in triads than in dyads. Third, positive emotion or affect has a stronger impact on cohesion in dyads than in triads, whereas uncertainty reduction has a stronger impact on cohesion in triads. To test these hypotheses, an experiment compared isolated dyads to dyads nested in a triadic exchange network. Subjects engaged in exchanges across a series of distinct episodes, using standard experimental procedures from research on relational cohesion (Lawler and Yoon, 1996) and exchange networks (Molm and Cook, 1995; Willer, 1999). Consistent with the hypotheses, the results reveal more convergence of behavior and higher cohesion in triads than in dyads; moreover, uncertainty reduction is the primary basis for cohesion in the triad, whereas positive affect was the primary basis for cohesion in the dyad. These results are discussed in relation to Simmelian dyad-triad dynamics and the theory of relational cohesion. PMID:24090845

  5. A study of team cohesion and player satisfaction in two face-to-face games

    OpenAIRE

    Martin, Eleanor; Good, Judith

    2013-01-01

    In this paper we investigate the link between game rules, team cohesion and players’ satisfaction with their teams within face-to-face team-based games. To measure team cohesion, rules from two games were analysed from the perspective of Social Identity Theory in order to form a hypothesis as to which game would be more likely to lead to more cohesive teams, where team cohesion is measured by the extent to which each player identifies with their team. Player satisfaction was measured by looki...

  6. Finite cohesion due to chain entanglement in polymer melts.

    Science.gov (United States)

    Cheng, Shiwang; Lu, Yuyuan; Liu, Gengxin; Wang, Shi-Qing

    2016-04-14

    Three different types of experiments, quiescent stress relaxation, delayed rate-switching during stress relaxation, and elastic recovery after step strain, are carried out in this work to elucidate the existence of a finite cohesion barrier against free chain retraction in entangled polymers. Our experiments show that there is little hastened stress relaxation from step-wise shear up to γ = 0.7 and step-wise extension up to the stretching ratio λ = 1.5 at any time before or after the Rouse time. In contrast, a noticeable stress drop stemming from the built-in barrier-free chain retraction is predicted using the GLaMM model. In other words, the experiment reveals a threshold magnitude of step-wise deformation below which the stress relaxation follows identical dynamics whereas the GLaMM or Doi-Edwards model indicates a monotonic acceleration of the stress relaxation dynamics as a function of the magnitude of the step-wise deformation. Furthermore, a sudden application of startup extension during different stages of stress relaxation after a step-wise extension, i.e. the delayed rate-switching experiment, shows that the geometric condensation of entanglement strands in the cross-sectional area survives beyond the reptation time τd that is over 100 times the Rouse time τR. Our results point to the existence of a cohesion barrier that can prevent free chain retraction upon moderate deformation in well-entangled polymer melts. PMID:26931322

  7. Ultrasonic probing of cohesive granular media at very low consolidation.

    Science.gov (United States)

    Botello, Francisco Ruiz; Castellanos, Antonio; Tournat, Vincent

    2016-07-01

    In this work, we study sound propagation in different granular media made of magnetite particles, steel particles, and glass beads consolidated under their own weight. We used two ultrasonic non invasive methods, which are found in good agreement, to estimate the longitudinal wave velocity Vp. In the first one, the velocity is determined through the resonance peaks of the powder slab. The second method determines the velocity with the time of flight of a short pulse traveling through the medium. Magnetite and steel samples show dispersive properties below a frequency ∼ 10kHz. The increase of attractive forces between particles lead to two competing effects; on one hand the solid fraction decreases and on the other hand the contacts are stiffer. A decrease in solid fraction implies that the number of contacts decreases leading to a decrease in the wave propagation velocity. On the other hand stronger contacts on average lead to an increase of sound velocity. In our experiments an increase in powder cohesion (caused by a decrease of the bead diameter) leads to an increase in sound velocity even though the solid fraction decreases. The same behavior is found in glass beads. These results show the predominant role of cohesive forces on sound propagation in loosely consolidated dry fine powders as well as the accuracy of ultrasonic methods for powder characterization. PMID:26683655

  8. Approche des notions de coherence et de cohesion sur un corpus oral (Applying the Notions of Coherence and Cohesion to an Oral Corpus).

    Science.gov (United States)

    Fillol, Francois; Mouchon, Jean

    1978-01-01

    Examines the narrations of several students of one event in order to analyze factors such as suprasegmentals, use of determiners, and verb forms, which contribute to cohesion and coherence in oral narration. (AM)

  9. Measuring erosion rates of contaminated cohesive sediments using laboratory and in-situ devices in combination: experiences of investigations in River Elbe and Saale

    Science.gov (United States)

    Noack, Markus; Gerbersdorf, Sabine; Hillebrand, Gudrun; Kasimir, Petra; Wieprecht, Silke

    2014-05-01

    Deposition of contaminated sediments in areas of no or low flow velocity such as groyne fields or impounded river stretches represent a significant thread to water quality if long-deposited sediments are remobilized during flood and storm events. In contrast to non-cohesive sediments the dynamics of cohesive sediments is not fully understood mainly because of multiple physico-chemical factors and variable biological influence. Hence, site-specific investigations are required to develop water management strategies as well as modelling approaches to predict the dynamic behavior of cohesive material. The Institute for Modelling Hydraulic and Environmental Systems (IWS, University of Stuttgart) has a strong experience in developing measuring strategies and techniques to deal with the complex interactions between biological and sedimentary characteristics regarding erosion and remobilization of cohesive material. Specifically, the detection of critical shear stresses for incipient motion of cohesive particles has been realized for both one laboratory device (SETEG) and an in-situ device. For site-specific investigations ideally both methods should be combined. The first method (SETEG) includes the on-site extraction of sediment cores allowing for depth-dependent analysis under controlled laboratory conditions, while the second one measures the surface only but reduces possible artifacts due to sediment withdrawal and transport. Both methods were applied at groyne fields and deposition areas of the River Elbe and River Saale, which are both heavily affected by pollution of anthropogenic contaminants mainly originating from the release of chemical industry before 1990. Next to the detection of critical shear stresses and erosion rates, further sedimentary attributes are analyzed such as particle size distribution, water content and density as well as biological attributes such as TOC and microbial mass. The analyses of the sediment cores result in vertical profiles for

  10. Use of a ring chromosome and pulsed-field gels to study interhomolog recombination, double-strand DNA breaks and sister-chromatid exchange in yeast

    International Nuclear Information System (INIS)

    The authors describe a system that uses pulsed-field gels for the physical detection of recombinant DNA molecules, double-strand DNA breaks (DSB) and sister-chromatid exchange in the yeast Saccharomyces cerevisiae. The system makes use of a circular variant of chromosome II (Chr. III). Meiotic recombination between this ring chromosome and a linear homolog produces new molecules of sizes distinguishable on gels from either parental molecule. They demonstrate that these recombinant molecules are not present either in strains with two linear Chr. III molecules or in rad50 mutants, which are defective in meiotic recombination. In conjunction with the molecular endpoints. They present data on the timing of commitment to meiotic recombination scored genetically. They have used x-rays to linearize circular Chr. III, both to develop a sensitive method for measuring frequency of DSB and as a means of detecting double-size circles originating in part from sister-chromatid exchange, which they find to be frequent during meiosis

  11. Cells from an immunodeficient patient (46BR) with a defect in DNA ligation are hypomutable but hypersensitive to the induction of sister chromatid exchanges

    International Nuclear Information System (INIS)

    A fibroblast cell strain, 46BR, derived from an immunodeficient patient is hypersensitive to the lethal effects of a wide range of DNA-damaging agents. It is also defective in strand-break rejoining after treatment with dimethyl sulfate and UV light. The present study shows that the cells have a defect in joining Okazaki-type fragments during DNA replication, supporting the interpretation that the basic defect is in ligation of DNA strands. The baseline level of sister chromatid exchange is slightly higher than in normal cells but it does not approach that of Bloom's syndrome or dyskeratosis congenita cells. Sensitivity to the induction of sister chromatid exchange and the hypersensitivity to the lethal effects of a set of DNA-damaging agents are correlated, implying that the basic defect influences both end points in similar manner. No 6-thioguanine-resistant mutants could be induced by either γ- or UV-irradiation in these cells, suggesting that error-prone repair pathways for damage induced by these agents may contain a common ligation step in human cells

  12. COHESIVE STRENGTH OF DENTIN RESISTÊNCIA COESIVA DA DENTINA

    Directory of Open Access Journals (Sweden)

    Flávio Fernando DEMARCO

    1997-07-01

    Full Text Available The bond strength of dentin adhesives to dentin has increased after each generation. Although dentin substratum is part of the bonding process, little importance has been given to measure dentin cohesive strength. The aim of this study was to evaluate the cohesive strength of dentin in human canines. Seventeen non carious canines were selected. All of them had been extracted for more than one year. The teeth were ground until dentin square samples with approximately 2 X 2 mm were obtained. They were embedded in acrylic resin and subjected to shear stress, in a Wolpert Machine, at a crosshead speed of 0.5 mm/min. The mean cohesive strength of dentin in shear mode was 33.95 (+-9.72 MPa. The fracture surfaces were observed under a X40 magnification. A finite element analysis was performed to observe the stress distribution as related to the shear test. The failure pattern was compatible with the shear test and also with the stress distribution in the finite element analysisA resistência de união dos adesivos dentinários tem sido aumentada com o desenvolvimento de cada nova geração. Pouca importância tem sido dada à resistência coesiva da dentina. A proposta deste estudo foi avaliar a resistência coesiva da dentina. Dezessete caninos humanos hígidos, os quais tinham sido extraídos há mais de um ano, foram usados. Os dentes foram desgastados até a obtenção de corpos-de-prova em dentina, de formato quadrangular, com tamanho aproximado de 2 X 2 mm. Os dentes foram incluídos em resina acrílica e, então, submetidos ao teste de cisalhamento em uma máquina de ensaios universais Wolpert, com uma velocidade de 0,5 mm/min. A resistência coesiva média da dentina no teste de cisalhamento foi de 33,95 (+- 9,72 MPa. O tipo de fratura foi analisado com um aumento de 40X. Foi realizada uma análise com elemento finito, para observar a distribuição do estresse relacionada com o teste de cisalhamento. O padrão de fratura encontrado foi compat

  13. Signaling Elaboration: Combining French Gerund Clauses with Lexical Cohesion Cues

    Directory of Open Access Journals (Sweden)

    Marianne Vergez-Couret

    2012-07-01

    Full Text Available In this paper, we focus on the Elaboration relation and on its automatic identification in French, using the theoretical framework of Segmented Discourse Representation Theory (SDRT. One of the information sources identified by the SDRT framework to infer the Elaboration relation is based on the existence of a potential subsumption link between the eventualities at stake, depending on lexical semantics and world knowledge. We investigate this claim by combining a weak syntactic marker of the Elaboration relation, namely the gerund clause, with lexical cohesion cues. We aim at automatically identifying gerund clauses which are Elaborations by finding cohesive links between the host main clause and the gerund clause. This approach makes it possible to accurately detect few cases of intra-sentential Elaborations in our corpus, confirming the fact that lexical cohesion cues are relevant for this task.Dans cet article, nous nous focalisons sur la relation d’Élaboration en français, telle qu’elle est décrite dans le modèle théorique de la SDRT (Segmented Discourse Representation Theory, et sur son identification automatique. Selon la SDRT, une des sources d’information permettant d’inférer la relation d’Élaboration est basée sur l’existence d’un lien de subsomption entre les types des éventualités des segments à relier, indiquant que le type de la seconde éventualité est un sous-type de celui de la première dans la sémantique lexicale des éventualités ou grâce à des connaissances du monde. Nous proposons de contribuer à cette question en combinant un indice de la relation d’Élaboration, i. e. la construction syntaxique du gérondif, et des indices de cohésion lexicale. Notre objectif est d’identifier automatiquement des propositions gérondives qui sont des Élaborations en repérant des indices de cohésion lexicale entre la proposition principale et la proposition gérondive. Cette approche permet de d

  14. Social Cohesion and the Labour Market: Societal Regimes of Civic Attitudes and Labour Market Regimes

    Science.gov (United States)

    Dimeglio, Isabelle; Janmaat, Jan Germen; Mehaut, Philippe

    2013-01-01

    The aim of this paper is to test the connections between the indicators used in the literature on social cohesion, which usually reflect "general" values or behaviours, and indicators specific to a particular space, namely the labour market. A key question is the stability of the social cohesion's indicators when moving from a societal level to…

  15. Effects of Lexical Cohesion and Macrorules on EFL Students' Main Idea Comprehension

    Science.gov (United States)

    Wilawan, Sujunya

    2011-01-01

    This study investigated the effects of an instructional procedure which incorporated lexical cohesion and macrorules to promote main idea comprehension of Thai EFL students. One hundred and six undergraduate students taking a reading module were randomly assigned to one of three teaching conditions: the combined use of lexical cohesion and…

  16. Anxiety Disorders and Latinos: The Role of Family Cohesion and Family Discord

    Science.gov (United States)

    Priest, Jacob B.; Denton, Wayne

    2012-01-01

    Family cohesion has shown to be associated with lower psychological distress and other risk behaviors for Latinos, but little is known about the relationship of family cohesion, family discord, and anxiety disorders. Using data from the National Latino and Asian American Study (n = 2,554), this study examines the relationship between family…

  17. An Investigation into the Use of Cohesive Devises in Iranian High School EFL Textbooks

    Directory of Open Access Journals (Sweden)

    Mansour Shabani

    2015-07-01

    Full Text Available The present study aimed at probing into the use of grammatical and lexical cohesive subdevices in Iranian high school EFL textbooks. To this end, the reading sections of three high school EFL textbooks and one pre-university EFL textbook were analyzed in terms of the distribution of grammatical and lexical cohesive subdevices. The results of One-way ANOVA illustrated that: athere are no significant differences among the frequencies of grammatical cohesive subdevices across grade 1 high school EFL textbook and the pre-university EFL textbook, bthere are significant differences among the frequencies of grammatical cohesive subdevices across grades 2 and 3 high school EFL textbooks. Moreover, the results of Chi-Square test showed that the significant values of all of the lexical cohesive subdevices were higher than .05 across each of the Iranian EFL high school textbooks. These findings can be beneficial for textbook writers, materials developers and EFL teachers.Keywords: EFL textbook; cohesion; grammatical cohesion; lexical cohesion

  18. Referential Cohesion and Logical Coherence of Narration after Closed Head Injury

    Science.gov (United States)

    Davis, G. Albyn; Coelho, Carl A.

    2004-01-01

    A group with closed head injury was compared to neurologically intact controls regarding the referential cohesion and logical coherence of narrative production. A sample of six stories was obtained with tasks of cartoon-elicited story-telling and auditory-oral retelling. We found deficits in the clinical group with respect to referential cohesion,…

  19. Influence of Sport Education on Group Cohesion in University Physical Education

    Science.gov (United States)

    Jenkins, Jayne M.; Alderman, Brandon L.

    2011-01-01

    The Sport Education ("SE") curricular model incorporated within university physical education Basic Instruction Program (BIP) may increase group cohesion. This study's purpose was to identify student perceptions of a BIP course taught within "SE," and investigate group cohesion in differing activity content. Participants included 430 students…

  20. Comparison of Group Cohesion, Class Participation, and Exam Performance in Live and Online Classes

    Science.gov (United States)

    Galyon, Charles E.; Heaton, Eleanore C. T.; Best, Tiffany L.; Williams, Robert L.

    2016-01-01

    Though class participation and group cohesion have shown some potential to promote student performance in conventional classrooms, their efficacy has not yet been demonstrated in an online-class setting. Group cohesion, defined as member attraction to and self-identification with a group, is thought to promote positive interdependence and the…

  1. Effects of a Low-Element Challenge Course on Abstinence Self-Efficacy and Group Cohesion

    Science.gov (United States)

    Clem, Jamie M.; Smith, Thomas E.; Richards, Kristin V.

    2012-01-01

    Substance abuse researchers identify self-efficacy and group cohesion as important components in alcohol and other drug-dependency treatment. Objectives: The purpose of this single-group, pretest-posttest study is to explore the therapeutic value of a challenge course intervention on the self-efficacy and group cohesion of nine chemically…

  2. Cohesion and Trauma: An Examination of a Collegiate Women's Volleyball Team

    Science.gov (United States)

    Fletcher, Teresa B.; Meyer, Barbara B.

    2009-01-01

    This study examined the effects of Adventure Based Counseling (i.e., a low-element challenge program) on the cohesion of a collegiate women's volleyball team. Results suggest postintervention improvements in team cohesion. The support created in the challenge experience also transferred to the players helping one another to grieve the untimely…

  3. Keeping It in the Family: ATRX Loss Promotes Persistent Sister Telomere Cohesion in ALT Cancer Cells.

    Science.gov (United States)

    Roake, Caitlin M; Artandi, Steven E

    2015-09-14

    In this issue of Cancer Cell, Ramamoorthy and Smith report that cancer cells that maintain their chromosome ends through alternative lengthening of telomeres (ALT) display persistent sister telomere cohesion. This delayed resolution of sister telomere cohesion depends upon the loss of ATRX and its histone-sequestering function and is associated with increased recombination between sister telomeres. PMID:26373274

  4. An Analysis of Textual Cohesion in a Passage from Maria Gripe's "Hugo och Josefin."

    Science.gov (United States)

    Andersson, Erik

    Sentence-by-sentence analysis of factual or propositional cohesion in the first 29 lines of a Swedish children's story finds several sources of coherence that contribute to its cohesion. First, the text receives much coherence from its description of a single event, a situation where happenings are normal and expected. Second, a rather primitive…

  5. Religious communities, immigration, and social cohesion in rural areas: Evidence from England

    NARCIS (Netherlands)

    R. Andrews (Rhys)

    2011-01-01

    textabstractReligious communities are important sources of bridging and bonding social capital that have varying implications for perceptions of social cohesion in rural areas. In particular, as well as cultivating cohesiveness more broadly, the bridging social capital associated within mainline rel

  6. Happier together. Social cohesion and subjective well-being in Europe.

    Science.gov (United States)

    Delhey, Jan; Dragolov, Georgi

    2016-06-01

    Despite mushrooming research on "social" determinants of subjective well-being (SWB), little is known as to whether social cohesion as a collective property is among the key societal conditions for human happiness. This article fills this gap in investigating the importance of living in a cohesive society for citizens' SWB. For 27 European Union countries, it combines the newly developed Bertelsmann Foundation's Cohesion Index with individual well-being data on life evaluation and psychological functioning as surveyed in the recent European Quality of Life Survey. The main results from multi-level analyses are as follows. First, Europeans are indeed happier and psychologically healthier in more cohesive societies. Second, all three core domains of cohesion increase individuals' SWB. Third, citizens in the more affluent part of Europe feel the positivity of social cohesion more consistently than those in the less affluent part. Finally, within countries, cohesion is good for the SWB of resource-rich and resource-poor groups alike. Our findings also shed new light on the ongoing debate on economic progress and quality of life: what makes citizenries of affluent societies happier is, in the first place, their capacity to create togetherness and solidarity among their members-in other words, cohesion. PMID:25683956

  7. Cohesive Adequacy in the Narrative Samples of School-Age Children Who Use African American English

    Science.gov (United States)

    Horton-Ikard, RaMonda

    2009-01-01

    Purpose: This study explored the type and adequacy of cohesive devices that are produced by school-age children who use African American English (AAE). Method: The language samples of 33 African American children, ages 7, 9, and 11 years, were transcribed, analyzed, and coded for AAE use and cohesive adequacy (e.g., personal reference,…

  8. Religious Communities, Immigration, and Social Cohesion in Rural Areas: Evidence from England

    Science.gov (United States)

    Andrews, Rhys

    2011-01-01

    Religious communities are important sources of bridging and bonding social capital that have varying implications for perceptions of social cohesion in rural areas. In particular, as well as cultivating cohesiveness more broadly, the bridging social capital associated within mainline religious communities may represent an especially important…

  9. Discourse Cohesion in the Verbal Interactions of Individuals Diagnosed with Autistic Disorder or Schizotypal Personality Disorder.

    Science.gov (United States)

    Baltaxe, Christiane A. M.; And Others

    1995-01-01

    This study compared high functioning adolescents and young adults with autism (n=8) or schizotypal personality disorder (n=9) in use of social language referencing. Both groups had similar rates, types, and patterns of cohesive reference errors, though subjects with schizotypal disorder used cohesive ties of reference more often and more correctly…

  10. A Computational Investigation of Cohesion and Lexical Network Density in L2 Writing

    Science.gov (United States)

    Green, Clarence

    2012-01-01

    This study used a new computational linguistics tool, the Coh-Metrix, to investigate and measure the differences in cohesion and lexical network density between native speaker and non-native speaker writing, as well as to investigate L2 proficiency level differences in cohesion and lexical network density. This study analyzed data from three…

  11. Cohesion Features in ESL Reading: Comparing Beginning, Intermediate and Advanced Textbooks

    Science.gov (United States)

    Plakans, Lia; Bilki, Zeynep

    2016-01-01

    This study of English as a second language (ESL) reading textbooks investigates cohesion in reading passages from 27 textbooks. The guiding research questions were whether and how cohesion differs across textbooks written for beginning, intermediate, and advanced second language readers. Using a computational tool called Coh-Metrix, textual…

  12. A comparison of cohesive features in IELTS writing of Chinese candidates and IELTS examiners

    Institute of Scientific and Technical Information of China (English)

    刘可

    2012-01-01

    This study aims at investigating cohesive ties applied in IELTS written texts produced by Chinese candidates and IELTS examiners,uncovering the differences in the use of cohesive features between the two groups,and analyzing whether the employment of cohesive ties is a possible problem in the Chinese candidates’ writing.Six written texts are analyzed in the study,with three Chinese candidates’ and three IELTS examiners’ IELTS writing respectively.The findings show that there exist differences in the use of cohesive devices between the two groups.Compared to the IETLS’ examiners’ writing,the group of Chinese candidates employed excessive conjunctions,with relatively less comparative and demonstrative reference ties used in their texts.Additionally,it appears that overusing repetition ties constitutes a potential problem in the candidates’ writing.Implications and suggestions about raising learners’ awareness and helping them to use cohesive devices effectively are discussed.

  13. A cohesive law for interfaces in graphene/hexagonal boron nitride heterostructure

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chenxi [Department of Mechanical and Aerospace Engineering, University of Miami, Coral Gables, Florida 33146 (United States); Lou, Jun [Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77251 (United States); Song, Jizhou, E-mail: jzsong@gmail.com [Department of Engineering Mechanics and Soft Matter Research Center, Zhejiang University, Hangzhou 310027 (China)

    2014-04-14

    Graphene/hexagonal boron nitride (h-BN) heterostructure has showed great potential to improve the performance of graphene device. We have established the cohesive law for interfaces between graphene and monolayer or multi-layer h-BN based on the van der Waals force. The cohesive energy and cohesive strength are given in terms of area density of atoms on corresponding layers, number of layers, and parameters in the van der Waals force. It is found that the cohesive law in the graphene/multi-layer h-BN is dominated by the three h-BN layers which are closest to the graphene. The approximate solution is also obtained to simplify the expression of cohesive law. These results are very useful to study the deformation of graphene/h-BN heterostructure, which may have significant impacts on the performance and reliability of the graphene devices especially in the areas of emerging applications such as stretchable electronics.

  14. Analysis of Cohesive Microsized Particle Packing Structure Using History-Dependent Contact Models

    CERN Document Server

    Tayeb, Raihan; Mao, Yijin; Zhang, Yuwen

    2016-01-01

    Granular packing structures of cohesive micro-sized particles with different sizes and size distributions, including mono-sized, uniform and Gaussian distribution, are investigated by using two different history dependent contact models with Discrete Element Method (DEM). The simulation is carried out in the framework of LIGGGHTS which is a DEM simulation package extended based on branch of granular package of widely used open-source code LAMMPS. Contact force caused by translation and rotation, frictional and damping forces due to collision with other particles or container boundaries, cohesive force, van der Waals force, and gravity are considered. The radial distribution functions (RDFs), force distributions, porosities, and coordination numbers under cohesive and non-cohesive conditions are reported. The results indicate that particle size and size distributions have great influences on the packing density for particle packing under cohesive effect: particles with Gaussian distribution have the lowest pac...

  15. A cohesive finite element formulation for modelling fracture and delamination in solids

    Indian Academy of Sciences (India)

    S Roy Chowdhury; R Narasimhan

    2000-12-01

    In recent years, cohesive zone models have been employed to simulate fracture and delamination in solids. This paper presents in detail the formulation for incorporating cohesive zone models within the framework of a large deformation finite element procedure. A special Ritz-finite element technique is employed to control nodal instabilities that may arise when the cohesive elements experience material softening and lose their stress carrying capacity. A few simple problems are presented to validate the implementation of the cohesive element formulation and to demonstrate the robustness of the Ritz solution method. Finally, quasi-static crack growth along the interface in an adhesively bonded system is simulated employing the cohesive zone model. The crack growth resistance curves obtained from the simulations show trends similar to those observed in experimental studies.

  16. Mode I Cohesive Law Characterization of Through-Crack Propagation in a Multidirectional Laminate

    Science.gov (United States)

    Bergan, Andrew C.; Davila, Carlos G.; Leone, Frank A.; Awerbuch, Jonathan; Tan, Tein-Min

    2014-01-01

    A method is proposed and assessed for the experimental characterization of through-the-thickness crack propagation in multidirectional composite laminates with a cohesive law. The fracture toughness and crack opening displacement are measured and used to determine a cohesive law. Two methods of computing fracture toughness are assessed and compared. While previously proposed cohesive characterizations based on the R-curve exhibit size effects, the proposed approach results in a cohesive law that is a material property. The compact tension specimen configuration is used to propagate damage while load and full-field displacements are recorded. These measurements are used to compute the fracture toughness and crack opening displacement from which the cohesive law is characterized. The experimental results show that a steady-state fracture toughness is not reached. However, the proposed method extrapolates to steady-state and is demonstrated capable of predicting the structural behavior of geometrically-scaled specimens.

  17. Bedform development and morphodynamics in mixed cohesive sediment substrates: the importance of winnowing and flocculation

    Science.gov (United States)

    Ye, Leiping; Parsons, Daniel; Manning, Andrew

    2016-04-01

    There remains a lack of process-based knowledge of sediment dynamics within flows over bedforms generated in complex mixtures of cohesionless sand and biologically-active cohesive muds in natural estuarine flow systems. The work to be presented forms a part of the UK NERC "COHesive BEDforms (COHBED)" project which aims to fill this gap in knowledge. Herein results from a field survey in sub-tidal zone of Dee estuary (NW, England) and a set of large-scale laboratory experiments, conducted using mixtures of non-cohesive sands, cohesive muds and Xanthan gum (as a proxy for the biological stickiness of Extracellular Polymeric Substances (EPS)) will be presented. The results indicate the significance of biological-active cohesive sediments in controlling winnowing rates and flocculation dynamics, which contributes significantly to rates of bedform evolution.

  18. Social Cohesion, Structural Holes, and a Tale of Two Measures

    Science.gov (United States)

    Latora, V.; Nicosia, V.; Panzarasa, P.

    2013-05-01

    In the social sciences, the debate over the structural foundations of social capital has long vacillated between two positions on the relative benefits associated with two types of social structures: closed structures, rich in third-party relationships, and open structures, rich in structural holes and brokerage opportunities. In this paper, we engage with this debate by focusing on the measures typically used for formalising the two conceptions of social capital: clustering and effective size. We show that these two measures are simply two sides of the same coin, as they can be expressed one in terms of the other through a simple functional relation. Building on this relation, we then attempt to reconcile closed and open structures by proposing a new measure, Simmelian brokerage, that captures opportunities of brokerage between otherwise disconnected cohesive groups of contacts. Implications of our findings for research on social capital and complex networks are discussed.

  19. Quantum-chemical approach to cohesive properties of metallic beryllium

    International Nuclear Information System (INIS)

    Calculations based upon the incremental approach, i.e. an expansion of the correlation energy in terms of one-body, two-body, and higher-order contributions from localized orbital groups, have been performed for metallic beryllium. We apply an embedding scheme which has been successfully applied recently to ground-state properties of magnesium and group 12 elements. This scheme forces localization in metallic-like model systems and allows for a gradual delocalization within the incremental approach. Quantum-chemical methods of the coupled-cluster and multi-reference configuration interaction type are used for evaluating individual increments. Results are given for the cohesive energy and lattice constants of beryllium, and it is shown that further development of the approach is needed for this difficult case

  20. Social cohesion, structural holes, and a tale of two measures

    CERN Document Server

    Latora, Vito; Panzarasa, Pietro

    2012-01-01

    In the social sciences, the debate over the structural foundations of social capital has long vacillated between two positions on the relative benefits associated with two types of social structures: closed structures, rich in third-party relationships; and open structures, rich in structural holes and brokerage opportunities. In this paper, we engage with this debate by focusing on the measures typically used for formalising the two conceptions of social capital: clustering and effective size. We show that these two measures are simply two sides of the same coin, as they can be expressed one in terms of the other through a simple functional relation. Building on this relation, we then attempt to reconcile closed and open structures by proposing a new measure, Simmelian brokerage, that captures opportunities of brokerage between otherwise disconnected cohesive groups of contacts. Implications of our findings for research on social capital and complex networks are discussed.

  1. One-Electron Theory of Metals. Cohesive and Structural Properties

    DEFF Research Database (Denmark)

    Skriver, Hans Lomholt

    means of the Linear Muffin-Tin Orbital (LMTO) method. It has been the goal of the work to establish how well this one-electron approach describes physical properties such as the crystal structures of the transition metals, the structural phase transitions in the alkali, alkaline earth, and rare earth......The work described in the report r.nd the 16 accompanying publications is based upon a one-electron theory obtained within the local approximation to density-functional theory, and deals with the ground state of metals as obtained from selfconsistent electronic-structure calculations performed by...... metals, and the localization of 3d, 4f, and 5f electrons in the 3d metal monoxides, the light lanthanides, and the actinides, respectively, as well as the cohesive properties of metals in general.!...

  2. Mechanisms of de cohesion in cutting aluminium matrix composites

    International Nuclear Information System (INIS)

    In this paper properties and applications of aluminium matrix composites are presented with a composite reinforced with saffil fibres selected for topical study. Behavior of matrix and reinforcement during machining with a cutting tool is analyzed. The paper presents an explosive quick-stop device designed to obtain undisturbed machined surface for examination. Meso hardness measurements of deformed structure, resultant chips and built-up-edge were carried out. Scanning micrographs of machined surface are presented with morphology and types of chips analysed. Values of the fibrousness angle ψ and thickening index kh of chip are evaluated. The research performed has enabled the authors to define mechanisms of e cohesion during cutting aluminium matrix composites. The results received for composite material are compared with those pertinent to aluminum alloys.

  3. Overtopping breaching of river levees constructed with cohesive sediments

    Science.gov (United States)

    Wei, Hongyan; Yu, Minghui; Wang, Dangwei; Li, Yitian

    2016-07-01

    Experiments were conducted in a bend flume to study the overtopping breaching process and the corresponding overflow rates of river levees constructed with cohesive sediments. The river and land regions were separated by the constructed levee in the bend flume. Results showed that the levee breaching process can be subdivided into a slope erosion stage, a headcut retreat stage and a breach widening stage. Mechanisms such as flow shear erosion, impinging jet erosion, side slope erosion and cantilever collapse were discovered in the breaching process. The erosion characteristics were determined by both flow and soil properties. Finally, a depth-averaged 2-D flow model was used to simulate the levee breaching flow rates, which is well expressed by the broad-crested weir flow formula. The deduced discharge coefficient was smaller than that of common broad-crested rectangular weirs because of the shape and roughness of the breach.

  4. Stress-compatible embedded cohesive crack in CST element

    DEFF Research Database (Denmark)

    Olesen, John Forbes; Poulsen, Peter Noe

    2010-01-01

    A simple element with an embedded strong discontinuity for modeling cohesive cracking of concrete is presented. The element differs from previous elements of the embedded type, in that a consistent stress field is obtained by direct enforcement of stress continuity across the crack. The...... displacement discontinuity is modeled in an XFEM fashion; however, the discontinuous displacement field is special, allowing for the direct enforcement of stress continuity. This in turn allows for elimination of extra degrees of freedom necessary for describing the crack deformations, thus the element has the...... same number of freedoms as its continuous basis: CST. The good performance of the element is demonstrated by its ability to simulate threepoint bending of a notched concrete beam. The advantage of the element is its simplicity and the straightforward implementation of it. Handling situations with...

  5. Method and apparatus for blending fine and cohesive powders in a fluidized bed with gas injection through ball valves

    International Nuclear Information System (INIS)

    A fluidized bed blender is described, suitable for blending powders including a mixture of fine and cohesive powders and in particular for converting a heterogeneous mixture of fine and cohesive UO2 into a homogeneous mixture. (U.K.)

  6. Analysis on the Cohesive and Coherent Features of John Kennedy’s First Inaugural Address

    Institute of Scientific and Technical Information of China (English)

    范莹芳

    2013-01-01

    John Kennedy’s first inaugural address is one of the widely appreciated speeches worldwide. It is famous not only for calling up the American people to well serve the country, but also for its extraordinary linguistic power to arouse the listeners’ emotions, which lies to a great extent in the marvelous employment of the cohesive and coherent devices in the process of its de⁃livery. Cohesion and coherence are two elementary and significant concepts in the theoretical system of discourse analysis. There⁃fore, they play an important role in the structuring, arrangement, interpretation and analysis of a discourse. In this sense, it is sig⁃nificant to analyze the cohesive and coherent features of John Kennedy’s first inaugural address in order to obtain a penetrating comprehension of the speech in many aspects. A detailed analysis on the cohesive and coherent features of the speech has been conducted in this paper. In the aspect of cohesion in the address, the devices employed fall into two categories: structural cohe⁃sion and non-structural cohesion. Structural cohesive devices used in the discourse are mainly grammatical cohesion and lexical cohesion like repetition, ellipsis, conjunction, etc. Non-structural methods adopted in the speech are transitivity, mood and mo⁃dality, thematic progression, parallel structure and so on. In the aspect of coherence, five levels of coherent methods have been employed, namely, lexical level, syntax level, semantic level, phonological level and social semiotic level. The neat intermingling of the cohesive and coherent methods function cooperatively and lead to the smooth going of the text.

  7. Discourse Structure Analysis for Requirement Mining

    OpenAIRE

    Juyeon Kang; Patrick Saint-dizier

    2014-01-01

    In this work, we first introduce two main approaches to writing requirements and then propose a method based on Natural Language Processing to improve requirement authoring and the overall coherence, cohesion and organization of requirement documents. We investigate the structure of requirement kernels, and then the discourse structure associated with those kernels. This will then enable the system to accurately extract requirements and their related contexts from texts (called requirement mi...

  8. Numerical simulation of cracks and interfaces with cohesive zone models in the extended finite element method, with EDF R and D software Code Aster

    International Nuclear Information System (INIS)

    In order to assess the harmfulness of detected defects in some nuclear power plants, EDF Group is led to develop advanced simulation tools. Among the targeted mechanisms are 3D non-planar quasi-static crack propagation, but also dynamic transients during unstable phases. In the present thesis, quasi-brittle crack growth is simulated based on the combination of the XFEM and cohesive zone models. These are inserted over large potential crack surfaces, so that the cohesive law will naturally separate adherent and de-bonding zones, resulting in an implicit update of the crack front, which makes the originality of the approach. This requires a robust insertion of non-smooth interface laws in the XFEM, which is achieved in quasi-statics with the use of XFEM-suited multiplier spaces in a consistent formulation, block-wise diagonal interface operators and an augmented Lagrangian formalism to write the cohesive law. Based on this concept and a novel directional criterion appealing to cohesive integrals, a propagation procedure over non-planar crack paths is proposed and compared with literature benchmarks. As for dynamics, an initially perfectly adherent cohesive law is implicitly treated within an explicit time-stepping scheme, resulting in an analytical determination of interface tractions if appropriate discrete spaces are used. Implementation is validated on a tapered DCB test. Extension to quadratic elements is then investigated. For stress-free cracks, it was found that a subdivision into quadratic sub-cells is needed for optimality. Theory expects enriched quadrature to be necessary for distorted sub-cells, but this could not be observed in practice. For adherent interfaces, a novel discrete multiplier space was proposed which has both numerical stability and produces quadratic convergence if used along with quadratic sub-cells. (author)

  9. Ultimate pier and contraction scour prediction in cohesive soils at selected bridges in Illinois

    Science.gov (United States)

    Straub, Timothy D.; Over, Thomas M.; Domanski, Marian M.

    2013-01-01

    The Scour Rate In COhesive Soils-Erosion Function Apparatus (SRICOS-EFA) method includes an ultimate scour prediction that is the equilibrium maximum pier and contraction scour of cohesive soils over time. The purpose of this report is to present the results of testing the ultimate pier and contraction scour methods for cohesive soils on 30 bridge sites in Illinois. Comparison of the ultimate cohesive and noncohesive methods, along with the Illinois Department of Transportation (IDOT) cohesive soil reduction-factor method and measured scour are presented. Also, results of the comparison of historic IDOT laboratory and field values of unconfined compressive strength of soils (Qu) are presented. The unconfined compressive strength is used in both ultimate cohesive and reduction-factor methods, and knowing how the values from field methods compare to the laboratory methods is critical to the informed application of the methods. On average, the non-cohesive method results predict the highest amount of scour, followed by the reduction-factor method results; and the ultimate cohesive method results predict the lowest amount of scour. The 100-year scour predicted for the ultimate cohesive, noncohesive, and reduction-factor methods for each bridge site and soil are always larger than observed scour in this study, except 12% of predicted values that are all within 0.4 ft of the observed scour. The ultimate cohesive scour prediction is smaller than the non-cohesive scour prediction method for 78% of bridge sites and soils. Seventy-six percent of the ultimate cohesive predictions show a 45% or greater reduction from the non-cohesive predictions that are over 10 ft. Comparing the ultimate cohesive and reduction-factor 100-year scour predictions methods for each bridge site and soil, the scour predicted by the ultimate cohesive scour prediction method is less than the reduction-factor 100-year scour prediction method for 51% of bridge sites and soils. Critical shear stress

  10. Erythrocytes modulate cell cycle progression but not the baseline frequency of sister chromatid exchanges in pig lymphocytes

    Directory of Open Access Journals (Sweden)

    Miguel A. Reigosa

    1997-09-01

    Full Text Available The effect of co-culturing varying concentrations of pig and human red blood cells (RBCs on the baseline frequency of sister chromatid exchanges (SCEs and cell-cycle progression in pig plasma (PLCs and whole blood leukocyte cultures (WBCs was studied. No variation in SCE frequency was observed between pig control WBC and PLC. Addition of pig and human RBCs to pig PLCs did not modify the baseline frequency of SCEs. On the other hand, cell proliferation was slower in PLCs than in WBCs. The addition of pig or human RBCs to PLCs accelerated the cell-cycle progression of pig lymphocytes. When RBCs were added to PLCs the concentration and time sequence of RBC incorporation affected the cell-cycle progression of swine lymphocytes. When doses of pig or human RBCs equivalent to those present in WBCs were added immediately after PLC stimulation, the cell-cycle kinetics were similar to those of WBCs. Shorter co-incubation periods or a reduction in the dose of RBCs made cell-cycle progression intermediate between PLC and WBC values. Thus, pig and human RBCs modulated the in vitro cell-cycle progression of pig lymphocytes in a time- and dose-dependent manner, and the low baseline frequency of SCEs of pig lymphocytes is independent of the presence or absence of erythrocytes in cultureFoi estudado o efeito de co-culturas com concentrações variadas de células sangüíneas vermelhas (RBCs suínas e humanas na freqüência basal de trocas de cromátides irmãs (SCEs e na progressão do ciclo celular em culturas de plasma de porco (PLCs e culturas leucocitárias do sangue total (WBCs. Não foi observada nenhuma variação na freqüências de SCEs entre os controles de WBC e PLC em porcos. A adição de RBCs de suínos e humanos a PLCs não modificou a freqüência basal de SCEs. Por outro lado, a proliferação celular foi mais lenta em PLCs que em WBCs. A adição de RBCs humanas ou suínas a PLCs acelerou a progressão do ciclo celular de linfócitos su

  11. Group cohesion in exercise classes: An examination of gender and type of exercise class differences

    Directory of Open Access Journals (Sweden)

    Hülya Aşçı

    2011-10-01

    Full Text Available Group cohesion has been attributed to the higher levels of attendance and performance and lower levels of drop-outs in exercise classes. Cohesion can be affected by different type of exercise classes and gender. Therefore, the main purpose of the study was to compare the group cohesion levels of martial arts participants (aikido, taekwondo, karate, and kendo with aerobic-like participants (aerobics, aero-steps, phys-gym, and high-low aerobics. This causal comparative study also aimed at examining sex differences in group cohesion in exercise classes. There were 140 participants (Mage=28.1 SD= 8.01 and female= 138 male= 2 in aerobic-like classes and 137 participants (Mage= 22.2 SD= 3.8 and female= 48 male= 89 in martial arts classes. Results revealed no sex differences between the groups on the perceptions of cohesion. On the other hand, except for individual attractions to the group-task dimension, participants of martial art classes had higher levels of group cohesion than the participants of aerobic-like classes. Consequently, it was concluded that different types of exercise classes may have different levels of cohesion and those differences were discussed within the context of exercise classes.

  12. E-Cohesion – a Simplification Method within European Union Rules

    Directory of Open Access Journals (Sweden)

    Paul Zai

    2015-05-01

    Full Text Available The e-cohesion is according to European Commission (EC a set of common rules for simplifying the accountancy and more precise reporting for European structural funds and European investment funds by using the digital technologies and public databases for all exchanges of information between the beneficiaries of projects financed with European funds and audit authorities, intermediate bodies, certifying authorities, managing authorities. The budget allocated for investments of the European Union (EU for period 2014- 2020 is of approximately a trillion Euros for sustainable growth, new jobs and competitiveness, solidarity and cohesion for an important role of EU in world. One of the ten points of reforms related with the cohesion politics refers to e-cohesion. The article outline the EU and Romania regulations prepared for e-cohesion target that is established for all EU countries in 2016. The paper is presenting the main opportunities and limits in the e-cohesion process for the horizon 2014-2020 using as methodology of study the computing and analysis based on the documentation published by EU, Netherlands and Romanian regulators. The study is also presenting the stage of e-cohesion changes reported by Netherlands and Romania.

  13. Interrelations between Energy Security Economics and Social Cohesion: Analysis of a Lithuanian Case

    Directory of Open Access Journals (Sweden)

    Dainius Genys

    2015-12-01

    Full Text Available Growing attention to sustainable development in academic discourse fosters discussions on how energy security affects society. In most cases the discussions consider the political and economic consequences, which affect or may affect the society. The aim of the article is to assess the impact of energy security economics on social cohesion in Lithuania. To achieve this aim the interrelations between energy security, energy economics and social cohesion are discussed. The theoretical framework of social cohesion (introduced by J. Jenson and P. Bernard is presented and applied in empirical analysis. The operationalization of empirical variables is based on economic, political and socio-cultural - activity areas, which are analyzed to verify the dichotomies between public attitudes and the actual behavior of society. These dichotomies help to distinguish six analytical dimensions, on the basis of which we created 17 empirical indicators, which analysis allows for describing the impact of Lithuanian energy security economics on social cohesion in quantitative data. The statistical analyses showed that the impact of attitudinal dimensions of energy security economics on social cohesion in Lithuania has an almost neutral effect: 3.05 (1-very negative; 3-neutral, 5-very positive. Whereas, the impact of behavioural dimensions of energy security economics on social cohesion has a negative effect: 2.47. The aggregated average of the overall impact of energy security economics on social cohesion in Lithuania has a negative effect: 2.76.

  14. Group cohesion in exercise classes: An examination of gender and type of exercise class differences

    Directory of Open Access Journals (Sweden)

    Selçuk Akpınar

    2011-10-01

    Full Text Available Group cohesion has been attributed to the higher levels of attendance and performance and lower levels of drop-outs in exercise classes. Cohesion can be affected by different type of exercise classes and gender. Therefore, the main purpose of the study was to compare the group cohesion levels of martial arts participants (aikido, taekwondo, karate, and kendo with aerobic-like participants (aerobics, aero-steps, phys-gym, and high-low aerobics. This causal comparative study also aimed at examining gender differences in group cohesion in exercise classes. There were 140 participants (Mage=28.1 SD= 8.01 and female= 138 male= 2 in aerobic-like classes and 137 participants (Mage= 22.2 SD= 3.8 and female= 48 male= 89 in martial arts classes. Results revealed no gender differences between the groups on the perceptions of cohesion. On the other hand, except for individual attractions to the group-task dimension, participants of martial art classes had higher levels of group cohesion than the participants of aerobic-like classes. Consequently, it was concluded that different types of exercise classes may have different levels of cohesion and those differences were discussed within the context of exercise classes. 

  15. Density and distribution of cohesive devices in the texts of literary and legal genres

    OpenAIRE

    Balevičienė, Dainora Ieva

    2014-01-01

    The aim of this paper was to analyze the impact of the genre on the use of cohesive devices in the literary and legal texts. To achieve the aim the following objectives were specified: to determine the typical patterns of the use of cohesive devices in literary and legal texts and to identify similarities and differences of the use of cohesive devices in the texts of different genres under investigation. The approaches to the research were quantitative and qualitative as well as content analy...

  16. How social network analysis can help to measure cohesion in collaborative distance-learning

    OpenAIRE

    Reffay, Christophe; Chanier, Thierry

    2003-01-01

    It has been argued that cohesion plays a central role in collaborative learning. In face-to-face classes, it can be reckoned from several visual or oral cues. In a Learning Management System or CSCL environment, such cues are absent. In this paper, we show that Social Network Analysis concepts, adapted to the collaborative distance-learning context, can help measuring the cohesion of small groups.Working on data extracted from a 10-week distance-learning experiment, we computed cohesion in se...

  17. The application of J integral to measure cohesive laws in materials undergoing large scale yielding

    DEFF Research Database (Denmark)

    Sørensen, Bent F.; Goutianos, Stergios

    2015-01-01

    We explore the possibility of determining cohesive laws by the J-integral approach for materials having non-linear stress-strain behaviour (e.g. polymers and composites) by the use of a DCB sandwich specimen, consisting of stiff elastic beams bonded to the non-linear test material, loaded with pure...... bending moments. For a wide range of parameters of the non-linear material, the plastic unloading during crack extension is small, resulting in J integral values (fracture resistance) that deviate maximum 15% from the work of the cohesive traction. Thus the method can be used to extract the cohesive laws...

  18. Cohesive model applied to fracture propagation in Indiana Limestone

    Science.gov (United States)

    Dewers, T. A.; Rinehart, A. J.; Bishop, J. E.

    2014-12-01

    We apply a cohesive fracture (CF) model to results of short-rod (SR), notched 3-point-bend (N3PB) tests, and Brazil tests in Indiana Limestone. Calibration and validation of the model are performed within a commercial finite element modeling platform. By using a linear traction-displacement softening response for a defined fracture-opening displacement (w1) following peak tensile stress (σcrit), the CF model numerically lumps different spatially distributed inelastic processes occurring at and around fracture tips into a thin zone within an elastic domain. Both the SR and the N3PB test specimen geometries use a notch partway through the sample to control the location of fracture propagation. We develop a mesh for both the SR and N3PB geometries with a narrow cohesive zone in the center of notches. From the Brazil tests, we find a tensile splitting stress (σsplit) of 5.9 MPa. We use a σsplit as the peak tensile stress (σcrit) for all simulations. The Young's modulus (E) and the critical crack opening distance (w1) of the CF model are calibrated against the SR data. The model successfully captures the elastic, yield, peak, and initial and late failure behavior and compares favorably against the N3PB tests. Differences in force-displacement and crack propagation are primarily caused by: more mixed-mode (shear and opening) crack propagation in N3PB than in SR tests, causing a higher peak; and transition from compression (high E) to tension (low E) in a larger volume of the N3PB sample than in the SR geometry. This material is based upon work supported as part of the Center for Frontiers of Subsurface Energy Security, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001114. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy

  19. The Application of Cohesion in English Reading and Writing Instruc-tion-Based on Diagnosis and Instruction Experiment

    Institute of Scientific and Technical Information of China (English)

    CHEN Ying-ying

    2014-01-01

    Based on Halliday and Hasan’s taxonomy of cohesive devices, the author investigates the deficiency of cohesive aware-ness of subjects through the analysis of questionnaires, interviews and problems existed in writing samples, and then the efficiency of applying cohesion theory to English teaching is examined through the data analysis of the results of the pre-test and post-test by SPSS Statistics 17.0. At last, the author draws the conclusion that applying cohesion theory to English teaching can, to a great extent, foster students’awareness of textual cohesion, develop their writing strategies, and improve their abilities of reading com-prehension.

  20. Effect of chlorophyllin on frequency radiation-induced of sister chromatid exchanges (SCE) and other cytogenetic events in mice bone marrow cells In Vivo

    International Nuclear Information System (INIS)

    The effect of chlorophyllin on gamma radiation induced Sister chromatid exchanges (SCE) and on the mitotic index (IM) and average generation time was determined. Groups of mice were treated in one of the following regimens: (1) untreated, (2) treated with chlorophyllin only, (3) irradiated and (4) treated with chlorophyllin and irradiated intraperitoneal administration of chlorophyllin preceding gamma radiation exposure protected again SCE induction and diminution of IM. However, radioprotection was not reflected in the average generation time for the chlorophyllin per se acceleration the average generation time. The results suggest that, under the experimental conditions of the study the SCE and IM are caused by free radicals produced by radiation and wat the action mechanics of chlorophyllin is scavenger free radicals. (Author)

  1. Sister chromatid exchanges, hyperdiploidy and chromosomal rearrangements studied in cells from melanoma-prone individuals belonging to families with the dysplastic nevus syndrome.

    Science.gov (United States)

    Jaspers, N G; Roza-de Jongh, E J; Donselaar, I G; Van Velzen-Tillemans, J T; van Hemel, J O; Rümke, P; van der Kamp, A W

    1987-01-01

    Cytogenetic investigations were performed on 25 individuals belonging to six melanoma-prone families with multiple melanocytic lesions (the dysplastic nevus syndrome, DNS). Patients having DNS with or without a history of melanoma were compared with clinically normal relatives and unrelated normal controls. The results indicate normal frequencies of hyperdiploidy and spontaneous sister chromatid exchanges in the fibroblasts of all individuals studied. Karyotypic analyses were carried out on the members of one family. The patients with DNS had a normal constitutional karyotype. In lymphocytes or fibroblasts from five patients, however, increased frequencies of cells with random chromosomal rearrangements were observed. These abnormalities, mainly translocations and inversions, were not found in two of the patients' spouses and in six clinically normal relatives. In the fibroblast cultures considerable clonal selection of cytogenetically abnormal cells occurred. PMID:3791172

  2. Genotoxicity of the anticonvulsant drug phenytoin (PHT): a follow-up study of PHT-untreated epileptic patients. I. Sister chromatid exchange (SCE) analysis.

    Science.gov (United States)

    Kaul, A; Goyle, S

    1999-01-01

    Phenytoin (PHT) is a widely prescribed antiepileptic drug. Its potential to interact with genetic material was investigated in a set of 30 epileptic patients (age 10-30 years) prior to and following the administration of PHT over a period of 9 months (grouped in a multiple of 3 months) and 40 control subjects in relation to age, sex, duration of drug therapy, and plasma concentration of PHT, using the sister chromatid exchange (SCE) frequency assay. Plasma levels of the phenytoin were measured by biochemical assay in epileptic patients before and after the PHT therapy. The peripheral blood lymphocytes were cultured and harvested at 72 h. The frequency of SCE was significantly higher (P genotoxic effect as expressed by the induction of increased SCE rates in treated epileptics, while disease does not play any role in inducing genetic damage as shown by no difference in SCE frequencies between control subjects and PHT-untreated epileptic patients. PMID:10321411

  3. The Aurora kinase Ipl1 maintains the centromeric localization of PP2A to protect cohesin during meiosis

    OpenAIRE

    Yu, Hong-Guo; Koshland, Douglas

    2007-01-01

    Homologue segregation during the first meiotic division requires the proper spatial regulation of sister chromatid cohesion and its dissolution along chromosome arms, but its protection at centromeric regions. This protection requires the conserved MEI-S332/Sgo1 proteins that localize to centromeric regions and also recruit the PP2A phosphatase by binding its regulatory subunit, Rts1. Centromeric Rts1/PP2A then locally prevents cohesion dissolution possibly by dephosphorylating the protein co...

  4. Induction of chromosome aberrations, sister chromatid exchanges and specific locus mutations by radiation and chemicals, and the application of the studies to population monitoring and risk estimation

    International Nuclear Information System (INIS)

    The major portion of the research of the Mammalian Cytogenetics Group can be considered to be directed towards estimating the genetic risk, and potentially the carcinogenicity, of radiation and chemical exposures to man. The approach taken is to attempt to determine the mechanism of induction of chromosome aberrations, sister chromatid exchanges and specific locus mutations, and to apply the information obtained to the interpretation of data from currently used assay systems, or for the development of new, more sensitive, or more predictive, assays. This report is divided into several sections, each one representing a separate series of experiments. There is a logical progression to the sections, and there is a clear relationship between them. The sections are: (1) x-ray-induced chromosome aberrations and the involvement of repair of DNA base damage; (2) hypothesis for the mechanism of induction of chromosome aberrations; (3) the induction of chromosome aberrations in lymphocytes from Down's syndrome individuals; (4) the induction of chromosome aberrations by chemical agents; (5) interactive effects of radiation and chemical agents; (6) risk estimation and population monitoring; (7) the mechanism of induction of sister chromatid exchanges and specific locus mutations; and (8) studies with a transplantable mouse myeloid leukemia - an animal model. The intention of these studies is to improve our ability to extrapolate from data obtained with laboratory animals to the likely outcome in man, in order to provide estimates of the genetic, and potentially the carcinogenic, risk to man from exposures to radiation and chemical agents. There are several studies that have been recently initiated but are not reported here because of limited results so far. These particularly involve the development or improvement of assay systems to provide a greater predictive value or greater sensitivity

  5. A comparative investigation of DNA strand breaks, sister chromatid exchanges and K-ras gene mutations induced by cadmium salts in cultured human cells

    International Nuclear Information System (INIS)

    Cadmium (Cd) is a toxic heavy metal of continuing occupational and environmental concern with a wide variety of adverse effects. Several studies have shown that cadmium produces DNA strand breaks, DNA-protein cross-links, oxidative DNA damage, chromosomal aberrations, dysregulation of gene expression resulting in enhanced proliferation, depressed apoptosis and/or altered DNA repair. This study was undertaken to investigate the ability of cadmium chloride (CdCl2) and cadmium sulphate (CdSO4) to induce point mutations in codon 12 of the K-ras protooncogene assessed by polymerase chain reaction-single strand conformation polymorphisms (PCR-SSCP) and RFLP-enriched PCR methods. Also their genotoxic effects were analyzed by the comet assay and sister chromatid exchanges test. The human lung fibroblast cell line MRC-5 was used for the experiments. Sister chromatid exchanges assay (SCEs) frequencies were significantly increased in cells exposed to cadmium salts in relation to controls (p < 0.001). Despite the slow increment observed in the three comet parameters considered when cells were treated with cadmium chloride, significant differences between groups were only found in the variable comet moment (CM) (p < 0.005). On the other hand, when cells were exposed to cadmium sulphate, the Kruskal-Wallis test showed highly significant differences between groups for migration, tail moment and comet moment parameters (p < 0.001). Nevertheless, a null or weak point mutation induction in K-ras protooncogene was detected using polymerase chain reaction-low ionic strength-single strand conformation polymorphisms (PCR-LIS-SSCP) and RFLP-enriched PCR methods when cells were treated with cadmium salts. Thus, inorganic cadmium produces genotoxicity in human lung fibroblast MRC-5 cells, in the absence of significant point mutation of the K-ras gene

  6. Identifying Clusters of Concepts in a Low Cohesive Class for Extract Class Refactoring Using Metrics Supplemented Agglomerative Clustering Technique

    CERN Document Server

    Rao, A Ananda

    2012-01-01

    Object oriented software with low cohesive classes can increase maintenance cost. Low cohesive classes are likely to be introduced into the software during initial design due to deviation from design principles and during evolution due to software deterioration. Low cohesive class performs operations that should be done by two or more classes. The low cohesive classes need to be identified and refactored using extract class refactoring to improve the cohesion. In this regard, two aspects are involved; the first one is to identify the low cohesive classes and the second one is to identify the clusters of concepts in the low cohesive classes for extract class refactoring. In this paper, we propose metrics supplemented agglomerative clustering technique for covering the above two aspects. The proposed metrics are validated using Weyuker's properties. The approach is applied successfully on two examples and on a case study.

  7. Effective Cohesive Behavior of Layers of Interatomic Planes

    Science.gov (United States)

    Braides, Andrea; Lew, Adrian J.; Ortiz, Michael

    2006-05-01

    A simple model of cleavage in brittle crystals consists of a layer of material containing N atomic planes separating in accordance with an interplanar potential under the action of an opening displacement δ prescribed on the boundary of the layer. The problem addressed in this work concerns the characterization of the constrained minima of the energy E N of the layer as a function of δ as N becomes large. These minima determine the effective or macroscopic cohesive law of the crystal. The main results presented in this communication are: (i) the computation of the Γ limit E 0 of E N as N → ∞; (ii) the characterization of the minimum values of E 0 as a function of the macroscopic opening displacement; (iii) a proof of uniform convergence of the minima of E N for the case of nearest-neighbor interactions; and (iv) a proof of uniform convergence of the derivatives of E N , or tractions, in the same case. The scaling on which the present Γ-convergence analysis is based has the effect of separating the bulk and surface contributions to the energy. It differs crucially from other scalings employed in the past in that it renders both contributions of the same order.

  8. Direct numerical simulations of collision efficiency of cohesive sediments

    Science.gov (United States)

    Zhang, Jin-Feng; Maa, Jerome P.-Y.; Zhang, Qing-He; Shen, Xiao-Teng

    2016-09-01

    A clear understanding of the collision efficiency of cohesive sediment particles is critical for more accurate simulation of the flocculation processes. It is difficult, if not impossible, to carry out laboratory experiments to determine the collision efficiency for small particles. Direct Numerical Simulation (DNS) is a relatively feasible approach to describe the motion of spherical particles under gravity in calm water, and thus, to study the collision efficiency of these particles. In this study, the Lattice Boltzmann (LB) method is used to calculate the relative trajectories of two approaching particles with different ratios of sizes and densities. Results show that the inter-molecular forces (i.e., van der Waals attractive force, electrostatic repulsive/attractive force, and displacement force), which are usually neglected in previous studies, would affect the trajectories, and thus, lead to an overestimation of the collision efficiency. It is found that to increase the particle size ratio from 0.1 to 0.8 only slightly increases the collision efficiency, since the force caused by fluid-solid interaction between these two particles is reduced. To increase the submerged particle density ratio from 1 to 22, however, would significantly decrease the collision efficiency. Earlier analytical formulations of collision efficiency, which only consider the effects of particle size ratio, have significantly overestimated the collision efficiency (change from 0.01 to 0.6) when the particle size ratio is around 0.5.

  9. Examination of European Union economic cohesion: A cluster analysis approach

    Directory of Open Access Journals (Sweden)

    Jiri Mazurek

    2014-01-01

    Full Text Available In the past years majority of EU members experienced the highest economic decline in their modern history, but impacts of the global financial crisis were not distributed homogeneously across the continent. The aim of the paper is to examine a cohesion of European Union (plus Norway and Iceland in terms of an economic development of its members from the 1st of January 2008 to the 31st of December 2012. For the study five economic indicators were selected: GDP growth, unemployment, inflation, labour productivity and government debt. Annual data from Eurostat databases were averaged over the whole period and then used as an input for a cluster analysis. It was found that EU countries were divided into six different clusters. The most populated cluster with 14 countries covered Central and West Europe and reflected relative homogeneity of this part of Europe. Countries of Southern Europe (Greece, Portugal and Spain shared their own cluster of the most affected countries by the recent crisis as well as the Baltics and the Balkans states in another cluster. On the other hand Slovakia and Poland, only two countries that escaped a recession, were classified in their own cluster of the most successful countries

  10. Localized Disturbance in a 2D Cohesive Granular Packing

    Science.gov (United States)

    Rieser, Jennifer; Laplagne, Mathilde; Durian, Douglas

    2015-03-01

    How the local structural configuration influences large-scale deformation in disordered materials is not known. Inspired by nano-indentation experiments, we characterize the response of disordered granular packing to a localized disturbance by driving a triangular wedge into the packing. The extent of the disturbance is explored by performing experiments with several wedge angles. The two-dimensionality of the system allows for direct observation of all particle dynamics during the indentation. The grains can be cohesive, with an attraction governed by tunable capillary forces that are induced through an interstitial fluid. Topological quantities derived from a radical Voronoi diagram as well as the resulting triangulation are used to characterize local structure within the packing. Dynamics are characterized by local deformations to the triangulation as well as the local non-affine motion. For all wedge angles, a boundary develops between moving and static grains. This size and shape of this boundary depend on the indenter angle, and in all cases, the size of the boundary increases with time. During the deformation, non-affine grain motion occurs both throughout the moving region as well as along the boundary, while holes tend to develop primarily along this boundary. MRSEC/DMR-1120901.

  11. Cohesive granular media modelization with non-convex particles shape: Application to UO2 powder compaction

    International Nuclear Information System (INIS)

    We model in this work granular materials composed of non-convex and cohesive aggregates, in view of application to the rheology of UO2 powders. The effect of non convexity is analyzed in terms of bulk quantities (Coulomb internal friction and cohesion) and micromechanical parameters such as texture anisotropy and force transmission. In particular, we find that the packing fraction evolves in a complex manner with the shape non convexity and the shear strength increases but saturates due to interlocking between the aggregates. We introduce simple models to describe these features in terms of micro-mechanical parameters. Furthermore, a systematic investigation of shearing, uniaxial compaction and simple compression of cohesive packings show that bulk cohesion increases with non-convexity but is strongly influenced by the boundary conditions and shear bands or stress concentration. (author)

  12. A Molecular-Scale Understanding of Cohesion and Fracture in P3HT:Fullerene Blends

    KAUST Repository

    Tummala, Naga Rajesh

    2015-04-21

    Quantifying cohesion and understanding fracture phenomena in thin-film electronic devices are necessary for improved materials design and processing criteria. For organic photovoltaics (OPVs), the cohesion of the photoactive layer portends its mechanical flexibility, reliability, and lifetime. Here, the molecular mechanism for the initiation of cohesive failure in bulk heterojunction (BHJ) OPV active layers derived from the semiconducting polymer poly-(3-hexylthiophene) [P3HT] and two mono-substituted fullerenes is examined experimentally and through molecular-dynamics simulations. The results detail how, under identical conditions, cohesion significantly changes due to minor variations in the fullerene adduct functionality, an important materials consideration that needs to be taken into account across fields where soluble fullerene derivatives are used.

  13. Appraisal in a Team Context: Perceptions of Cohesion Predict Competition Importance and Prospects for Coping.

    Science.gov (United States)

    Wolf, Svenja A; Eys, Mark A; Sadler, Pamela; Kleinert, Jens

    2015-10-01

    Athletes' precompetitive appraisal is important because it determines emotions, which may impact performance. When part of a team, athletes make their appraisal within a social context, and in this study we examined whether perceived team cohesion, as a characteristic of this context, related to appraisal. We asked 386 male and female intercollegiate team-sport athletes to respond to measures of cohesion and precompetitive appraisal before an in-season game. For males and females, across all teams, (a) an appraisal of increased competition importance was predicted by perceptions of higher task cohesion (individual level), better previous team performance, and a weaker opponent (team level) and (b) an appraisal of more positive prospects for coping with competitive demands was predicted by higher individual attractions to the group (individual level). Consequently, athletes who perceive their team as more cohesive likely appraise the pending competition as a challenge, which would benefit both emotions and performance. PMID:26524095

  14. Loss of ATRX Suppresses Resolution of Telomere Cohesion to Control Recombination in ALT Cancer Cells.

    Science.gov (United States)

    Ramamoorthy, Mahesh; Smith, Susan

    2015-09-14

    The chromatin-remodeler ATRX is frequently lost in cancer cells that use ALT (alternative lengthening of telomeres) for telomere maintenance, but its function in telomere recombination is unknown. Here we show that loss of ATRX suppresses the timely resolution of sister telomere cohesion that normally occurs prior to mitosis. In the absence of ATRX, the histone variant macroH2A1.1 binds to the poly(ADP-ribose) polymerase tankyrase 1, preventing it from localizing to telomeres and resolving cohesion. The resulting persistent telomere cohesion promotes recombination between sister telomeres, while it suppresses inappropriate recombination between non-sisters. Forced resolution of sister telomere cohesion induces excessive recombination between non-homologs, genomic instability, and impaired cell growth, indicating the ATRX-macroH2A1.1-tankyrase axis as a potential therapeutic target in ALT tumors. PMID:26373281

  15. The weakness of strong ties : Collective action failure in a highly cohesive group

    NARCIS (Netherlands)

    Flache, A; Macy, MW

    1996-01-01

    Following Homans, exchange theorists have modeled informal social control as an exchange of peer approval for compliance with group obligations. The exchange model predicts higher compliance in cohesive networks with strong social ties. However, previous specifications failed to incorporate bilatera

  16. Associations of smoking prevalence with individual and area level social cohesion

    OpenAIRE

    Patterson, J.; Eberly, L.; Ding, Y.; Hargreaves, M.

    2004-01-01

    Study objective: To discover if area level social cohesion, neighbourhood safety, and home safety are associated with current cigarette smoking among adults after adjustment for concentrations of poverty and low education.

  17. Identification of Nominated Classes for Software Refactoring Using Object-Oriented Cohesion Metrics

    Directory of Open Access Journals (Sweden)

    Safwat M. Ibrahim

    2012-03-01

    Full Text Available The production of well-developed software reduces the cost of the software maintainability. Therefore, many software metrics have been developed to measure the quality of the software design. Measuring class cohesion is considered as one of the most important software quality measurements. Unfortunately, most of approaches that have been proposed on cohesion metrics do not consider the inherited attributes and methods in measuring class cohesion. This paper provides a novel assessment criterion for measuring the quality of a software design. In this context, inherited attributes and methods are considered in the assessment. This offers a guideline for choosing the proper Depth of Inheritance Tree (DIT that refers to the nominated classes for refactoring. Experiments are carried out on more than 35K classes from more than 16 open-source projects using the most used cohesion metrics.

  18. Transformational leadership and task cohesion in sport: the mediating role of inside sacrifice.

    Science.gov (United States)

    Cronin, Lorcan Donal; Arthur, Calum Alexander; Hardy, James; Callow, Nichola

    2015-02-01

    In this cross-sectional study, we examined a mediational model whereby transformational leadership is related to task cohesion via sacrifice. Participants were 381 American (Mage = 19.87 years, SD = 1.41) Division I university athletes (188 males, 193 females) who competed in a variety of sports. Participants completed measures of coach transformational leadership, personal and teammate inside sacrifice, and task cohesion. After conducting multilevel mediation analysis, we found that both personal and teammate inside sacrifice significantly mediated the relationships between transformational leadership behaviors and task cohesion. However, there were differential patterns of these relationships for male and female athletes. Interpretation of the results highlights that coaches should endeavor to display transformational leadership behaviors as they are related to personal and teammate inside sacrifices and task cohesion. PMID:25730889

  19. Performance of information system implementation based on coupling-cohesion among subunits

    Institute of Scientific and Technical Information of China (English)

    Wang Tienan; Li Yijun; Wang Mingzhu

    2007-01-01

    The intermediate information system benefit and the coupling-cohesion of subunits are presented to study the performance of information system implementation. Based on the organizational information processing theory and the organizational behaviour theory, a theoretical model is established from the perspective of coupling-cohesion of subunits. The reliability and validity of the model are checked up with the structural equation models and the data collected with questionnaires. The results of the study give some theoretical and practical guidance.

  20. Structural quality of polyacrylamide-treated cohesive soils in the coastal tablelands of Pernambuco

    Directory of Open Access Journals (Sweden)

    Diego Vandeval Maranhão de Melo

    2014-04-01

    Full Text Available Water-soluble polymers are characterized as effective flocculating agents due to their molecular features. Their application to soils with horizons with structural problems, e.g, a cohesive character, contributes to improvements in the physical quality and thus to the agricultural suitability of such soils. The purpose of this study was to evaluate the structural quality of soils with cohesive horizons of coastal tablelands in the State of Pernambuco treated with polyacrylamide (PAM as chemical soil conditioner. To this end, three horizons (one cohesive and two non-cohesive of a Yellow Argisol (Ultisol were evaluated and to compare cohesive horizons, the horizon of a Yellow Latosol (Oxisol was selected. The treatments consisted of aqueous PAM solutions (12.5; 50.0; 100.0 mg kg-1 and distilled water (control. The structural aspects of the horizons were evaluated by the stability (soil mass retained in five diameter classes, aggregate distribution per size class (mean weight diameter- MWD, geometric mean diameter - GMD and the magnitude of the changes introduced by PAM by measuring the sensitivity index (Si. Aqueous PAM solutions increased aggregate stability in the largest evaluated diameter class of the cohesive and non-cohesive horizons, resulting in higher MWD and GMD, with highest efficiency of the 100 mg kg-1 solution. The cohesive horizon Bt1 in the Ultisol was most sensitive to the action of PAM, where highest Si values were found, but the structural quality of the BA horizon of the Oxisol was better in terms of stability and aggregate size distribution.

  1. Smoke-free coalition cohesiveness in rural tobacco-growing communities.

    Science.gov (United States)

    Butler, Karen M; Begley, Kathy; Riker, Carol; Gokun, Yevgeniya; Anderson, Debra; Adkins, Sarah; Record, Rachael; Hahn, Ellen J

    2014-06-01

    Promoting tobacco control policies in rural tobacco-growing communities presents unique challenges. The purpose of this study was to assess smoke-free coalition cohesiveness in rural communities and identify coalition members' perceived barriers or divisive issues that impede the development of smoke-free policies. A secondary aim was to evaluate differences in coalition cohesiveness between advocates in communities receiving stage-based, tailored policy advocacy assistance versus those without assistance. Tobacco control advocates from 40 rural Kentucky communities were interviewed by telephone during the final wave of a 5-year longitudinal study of community readiness for smoke-free policy. On average, five health advocates per county participated in the 45-min interview. Participants rated coalition cohesiveness as not at all cohesive, somewhat cohesive, or very cohesive, and answered one open-ended question about potentially divisive issues within their coalitions. The mean age of the 186 participants was 48.1 years (SD = 13.3). The sample was predominantly female (83.6%) and Caucasian (99.5%). Divisive concerns ranged from rights issues, member characteristics, type of law, and whether or not to allow certain exemptions. Three of the divisive concerns were significantly associated with their rankings of coalition cohesiveness: raising tobacco in the community, the belief that smoke-free would adversely affect the economy, and government control. Educating coalition members on the economics of smoke-free laws and the actual economic impact on tobacco-growing may promote smoke-free coalition cohesiveness. More resources are needed to support policy advocacy in rural tobacco-growing communities as well as efforts to reduce the divisive concerns reported in this study. PMID:24338076

  2. Peacekeeping and U.N. operational control: a study of their effect on unit cohesion

    OpenAIRE

    Cunningham, Ernest G.

    1995-01-01

    Unit cohesion, the human element in combat, is critical to a unit's ability to survive and conduct successful warfare. Several factors can degrade unit cohesion and subsequently, combat effectiveness. This study concentrates on two such factors, U.S./U.N. operational control and operations other than war (OOTW). A survey was conducted on 300 U.S. Marine Corps soldiers. The results revealed that non-traditional missions were acceptable to a majority of the soldiers if these missions were condu...

  3. MODELING OF THE HIGH CONCENTRATION LAYER OF COHESIVE SEDIMENT UNDER THE ACTION OF WAVES AND CURRENTS

    Institute of Scientific and Technical Information of China (English)

    Qinghe ZHANG; Yongsheng WU; Jijian LIAN; Pingxing DING

    2001-01-01

    High concentration layer of cohesive sediment frequently occurs in muddy estuaries and coastal zones, and causes rapid siltation of the waterways. A one dimensional vertical coupled model describing the interactions between waves, currents and suspended cohesive sediment is developed in the present paper. The numerical results and analyses with field measurements reveal the mechanism of the formation and transport behaviors of the layer under the action of waves and currents.

  4. On the Role of Social Identity and Cohesion in Characterizing Online Social Communities

    OpenAIRE

    Purohit, Hemant; Ruan, Yiye; Fuhry, David; Parthasarathy, Srinivasan; Sheth, Amit

    2012-01-01

    Two prevailing theories for explaining social group or community structure are cohesion and identity. The social cohesion approach posits that social groups arise out of an aggregation of individuals that have mutual interpersonal attraction as they share common characteristics. These characteristics can range from common interests to kinship ties and from social values to ethnic backgrounds. In contrast, the social identity approach posits that an individual is likely to join a group based o...

  5. Improving Participation Rates for Women of Color in Health Research: The Role of Group Cohesion

    OpenAIRE

    Smith-Ray, Renae L.; Mama, Scherezade; Reese-Smith, Jacqueline Y; Estabrooks, Paul A.; Lee, Rebecca E

    2012-01-01

    Adherence to physical activity and dietary interventions is a common challenge. Interventions that use group cohesion strategies show promise for increasing adherence, but have not been tested among women of color. The purpose of this study was to determine whether dimensions of group cohesion mediate the association between intervention condition and attendance within a community physical activity program for women of color. African American and Hispanic or Latina women (N=310) completed mea...

  6. Trajectories of Early Binge Drinking: A Function of Family Cohesion and Peer Use.

    Science.gov (United States)

    Soloski, Kristy L; Kale Monk, J; Durtschi, Jared A

    2016-01-01

    Using the National Longitudinal Study of Adolescent Health, we tested latent growth models examining whether the number of friends using alcohol and family cohesion were linked with trajectories of binge drinking (N = 3,342) from adolescence (average age 15.06) into young adulthood (average age 27.93). Adolescents with higher family cohesion had lower rates of binge drinking in adolescence (b = -.07, p Group Interventions as a potential approach. PMID:25585579

  7. The Impact of Group Cohesiveness on Organizational Performance: The Nigerian Case

    OpenAIRE

    Adeleke Oladapo Banwo; Jianguo Du; Uchechi Onokala

    2015-01-01

    Several scholarly studies have associated strong group performance with a high level of group cohesion among the members. In this study, we investigated the impact of group cohesion on organizational performance using Carron, Widmeyer, and Brawley group environment questionnaire and Beauchamp, Bray and Carron (2002) role perception and acceptance scale administered to 180 employees in four branches of a commercial bank in Nigeria. The questionnaire was divided into three sections: demographic...

  8. The Role of Neighbours Selection on Cohesion and Order of Swarms

    OpenAIRE

    Angelo M Calvão; Edgardo Brigatti

    2014-01-01

    We introduce a multi-agent model for exploring how selection of neighbours determines some aspects of order and cohesion in swarms. The model algorithm states that every agents' motion seeks for an optimal distance from the nearest topological neighbour encompassed in a limited attention field. Despite the great simplicity of the implementation, varying the amplitude of the attention landscape, swarms pass from cohesive and regular structures towards fragmented and irregular configurations. I...

  9. Improving Decision Speed, Accuracy and Group Cohesion through Early Information Gathering in House-Hunting Ants

    OpenAIRE

    Nathalie Stroeymeyt; Martin Giurfa; Franks, Nigel R.

    2010-01-01

    BACKGROUND: Successful collective decision-making depends on groups of animals being able to make accurate choices while maintaining group cohesion. However, increasing accuracy and/or cohesion usually decreases decision speed and vice-versa. Such trade-offs are widespread in animal decision-making and result in various decision-making strategies that emphasize either speed or accuracy, depending on the context. Speed-accuracy trade-offs have been the object of many theoretical investigations...

  10. Unit cohesion and the military's "Don't ask, Don't Tell" policy

    OpenAIRE

    Rea, Theresa M.

    1997-01-01

    The Department of Defense policy of excluding known homosexuals from military service is partially based on the assumption that homosexual service members pose a threat to the cohesion of a military unit. The assumption is drawn largely from anecdotal evidence suggesting that junior service members would be uncomfortable in an environment that accepted homosexuals. This thesis examines the attitudes and opinions of junior officers to determine various aspects of unit cohesion that may be affe...

  11. Why Do MEPs Defect? An Analysis of Party Group Cohesion in the 5 th European Parliament

    OpenAIRE

    Thorsten Faas

    2002-01-01

    This study analyses party group cohesion and patterns of defections of national party delegations from party group lines in the present European Parliament, using a total of 1,370 roll call votes. The study confirms previous findings according to which party groups in the EP show (surprisingly) high levels of cohesion. In addition and notwithstanding that, it reveals the circumstances under which MEPs and their national delegations are more likely to defect. Among other factors, it was analys...

  12. Enhancing cohesion in Thai postgraduate students' expository writing through feedback delivery and revision

    OpenAIRE

    Tangkiengsirisin, Supong

    2010-01-01

    This study investigated the effects of teacher written feedback and students' revision on the use of cohesive devices in expository compositions written by thirty Thai postgraduate students enrolled in a 16-week writing course at a Thai university. The teacher written comments, including corrective, advisory and indicative comments, were provided to the students' cause-effect, comparison/contrast and classification essays. The feedback on cohesion in this study dealt with form, content and, m...

  13. Selected aspects of territorial cohesion in Slovakia under the recent crisis

    OpenAIRE

    Jaššo Matej; Finka Maroš

    2010-01-01

    Territorial cohesion has been one of the most prominent topics of discourse among spatial planners, urban sociologists, economists and experts from various other fields. Territorial systems with high degree of cohesion are better equipped to withstand the external pressures and situational imbalancies. Recent global crisis exposed these imbalancies and challenged the smooth and balanced spatial development of European countries. Major economic setbacks influenced entire society in Slova...

  14. Territorial cohesion and regional development ‚Äí case of Bosnia and Herzegovina

    OpenAIRE

    Jasmina Osmankovic; Rabija Somun

    2011-01-01

    Territorial cohesion and regional development ‚Äí case of Bosnia and Herzegovina In paper we analyzed territorial cohesion and regional development in Bosnia and Herzegovina from 1995 to 2010. In the context this theme we analyzed convergence and disproportional into Bosnia and Herzegovina during the postwar period. We used relevant statistical methods. We focus on demographic data and standard macroeconomic data (gross domestic product, gross domestic product per capita, employment rate, u...

  15. Analysis of Cohesion and Collective Efficacy Profiles for the Performance of Soccer Players

    OpenAIRE

    Leo, Francisco M.; Sánchez-Miguel, Pedro A.; Sánchez-Oliva, David; Amado, Diana; García-Calvo, Tomás

    2013-01-01

    The principal aims of the study were to define different profiles of cohesion and perceived efficacy in soccer players and to measure their differences in performance. The subjects were 235 soccer players in the under-18 category who played in the National League in Spain and 15 coaches whose ages ranged from 29 to 45 years. Diverse instruments to assess cohesion, perceived efficacy, and expectations of success were used in the study. Moreover, we measured playing time and performance. The re...

  16. The Application of Textual Cohesion and Coherence to the Teaching of College English Intensive Reading

    Institute of Scientific and Technical Information of China (English)

    林隆清

    2007-01-01

    In the process of college English intensive reading teaching,the analysis of textual cohesion and coherence is of great significance in that it can help students better understand the structure and contents of the teaching mterials,improve their ability in commnding and applying the language,thus improving the quality of college English teaching.This paper tries to analyze how to apply the theory of textual cohesion and coherence to the teaching of college English intensive reading.

  17. Is It Ethnic Fractionalization or Social Exclusion, which affects Social Cohesion?

    OpenAIRE

    Staveren, Irene; Zahid PERVAIZ

    2015-01-01

    markdownabstractThe theory about missing links of economic growth often lags behind the empirical estimations of such links. A consensus has emerged that ethnic fractionalization has a negative impact on growth, also when controlled for income inequality. Often, although implicitly, the assumed channel is social cohesion. We analyse the effect of fractionalization on social cohesion with a different inequality measure, namely a social measure of inequality: the Inclusion of Minorities Index. ...

  18. Social Network Influences on Adolescent Substance Use: Disentangling Structural Equivalence from Cohesion

    OpenAIRE

    FUJIMOTO, KAYO; Valente, Thomas W.

    2012-01-01

    This study investigates two contagion mechanisms of peer influence based on direct communication (cohesion) versus comparison through peers who occupy similar network positions (structural equivalence) in the context of adolescents' drinking alcohol and smoking. To date, the two contagion mechanisms have been considered observationally inseparable, but this study attempts to disentangle structural equivalence from cohesion as a contagion mechanism by examining the extent to which the transmis...

  19. Modelling the quasi-static behaviour of bituminous material using a cohesive zone model

    OpenAIRE

    Tabakovic, Amir; Karac, Aleksandar; Ivankovic, Alojz; Gibney, Amanda; McNally, Ciaran; Gilchrist, M. D.

    2010-01-01

    This paper investigates the applicability of a cohesive zone model for simulating the performance of bituminous material subjected to quasistatic loading. The Dugdale traction law was implemented within a finite volume code in order to simulate the binder course mortar material response when subjected to indirect tensile loading. A uniaxial tensile test and a threepoint bend test were employed to determine initial stress-strain curves at different test rates and the cohesive zone parameters (...

  20. Religious communities, immigration, and social cohesion in rural areas: Evidence from England

    OpenAIRE

    Andrews, Rhys

    2011-01-01

    textabstractReligious communities are important sources of bridging and bonding social capital that have varying implications for perceptions of social cohesion in rural areas. In particular, as well as cultivating cohesiveness more broadly, the bridging social capital associated within mainline religious communities may represent an especially important source of support for the social integration of new immigrant groups. Although the bonding social capital associated with evangelical commun...

  1. Family cohesion as a longevity factor of business with intergenerational transmission

    OpenAIRE

    Fernández-Roca, Fco. Javier; López-Manjón, Jesús D.; Gutiérrez-Hidalgo, Fernando

    2014-01-01

    This article contributes to a line of research in Business History that aims to determine the factors of family business longevity in the long term with the study of individual cases. The literature has identified family cohesion as one of the essential factors for survival. Cohesion may be reinforced or broken at the time of the intergenerational transfer. This study finds that a critical response on the part of the business family to the difficulties associated with intergenerational transf...

  2. The importance of grammatical cohesion in Conrad Aiken's Silent snow, secret snow

    OpenAIRE

    Piton, Salvador

    2010-01-01

    Abstract: The components of this paper are essentially based on grammatical cohesion which comprises reference (nominal and demonstrative), substitution and ellipsis (both nominal, verbal and clausal) and were selected from "Silent Snow, Secret Snow" by Conrad Aiken. Considering the language used by the author and by virtue of the cohesive peculiarity of the short story, we proposed a division of the text into two distinct parts, presenting, there fore, a new perspective in terms of structure...

  3. On the excavation process of a moving vertical jet in cohesive soil

    OpenAIRE

    Nobel, A.J.

    2013-01-01

    In dredging practice jetting is widely used for the excavation of soil. In this study the jetting process of a moving vertical jet in cohesive soil has been investigated. A number of jet tests were conducted on artificially prepared cohesive soil samples. The observed failure mechanisms are discussed. A calculation model to predict the jet cavity dimensions as function of the main jet and soil parameters is derived and verified.

  4. Cement grouting during installation of ground anchors in non-cohesive soils

    OpenAIRE

    Domes, Xenia A. L.

    2015-01-01

    Pressure grouting during installation of grouted ground anchors is known to increase anchor capacity in non-cohesive soils, but little information is available on correlations between applied grouting pressures, duration of grouting, ground conditions and increase of anchor pull-out capacity. The presented PhD study is concerned with processes taking place during installation of grouted ground anchors in non-cohesive soils, where filtration of the cement grout is assumed. It...

  5. Objects Are Individuals but Stuff Doesn't Count: Perceived Rigidity and Cohesiveness Influence Infants' Representations of Small Groups of Discrete Entities.

    Science.gov (United States)

    Huntley-Fenner, Gavin; Carey, Susan; Solimando, Andrea

    2002-01-01

    Two experiments probed 8-month-olds' ability to represent different kinds of entities: rigid, cohesive objects; flexible, cohesive objects; and non-rigid, non-cohesive portions of sand. Results suggest that the processes by which infants individuate and track entities are sensitive to material kind, rigid cohesive objects occupy a privileged…

  6. Theoretical and experimental approach to test the cohesion of calcium phosphate pastes

    Directory of Open Access Journals (Sweden)

    M Bohner

    2006-08-01

    Full Text Available Recent studies have revealed that the ability of a calcium phosphate cement paste to harden in a physiological environment without desintegrating into small particles might be a key property to ensure a safe and reliable clinical use of calcium phosphate cements. However, this property called cohesion is not well understood and has not been studied extensively. The goal of the present study was to better understand which factors affect the cohesion of a calcium phosphate paste using the combination of a theoretical and experimental approach. In the theoretical approach, factors expected to influence the paste cohesion such as Van der Waals forces, electrostatic and steric interactions, as well as osmotic effects were listed and discussed. In the experimental approach, a new method to measure the cohesion of a non-setting calcium phosphate paste was presented and used to assess the effects of various factors on this property. The new method allowed a continuous measurement of cohesion and gave reproducible results. The experimental results confirmed the theoretical predictions: an increase of the liquid-to-powder ratio of the paste and of the powder particle size, as well as the addition of citrate ions and in limited cases dissolved xanthan polymer chains reduced the paste cohesion.

  7. Analysis of cohesion and collective efficacy profiles for the performance of soccer players.

    Science.gov (United States)

    Leo, Francisco M; Sánchez-Miguel, Pedro A; Sánchez-Oliva, David; Amado, Diana; García-Calvo, Tomás

    2013-12-18

    The principal aims of the study were to define different profiles of cohesion and perceived efficacy in soccer players and to measure their differences in performance. The subjects were 235 soccer players in the under-18 category who played in the National League in Spain and 15 coaches whose ages ranged from 29 to 45 years. Diverse instruments to assess cohesion, perceived efficacy, and expectations of success were used in the study. Moreover, we measured playing time and performance. The results of the study proved the existence of four cohesion and efficacy profiles that presented significant differences in expectations of success, playing time, and performance. Furthermore, significant differences were found in the distribution of players in the teams as a function of performance. The main conclusion of this study is that soccer players with higher cohesion and collective efficacy levels belonged to teams that completed the season at the top-level classification. In contrast, athletes with low cohesion and collective efficacy usually played in unsuccessful teams. Coaches and sports psychologists are encouraged to promote both social and task cohesion and collective efficacy to enhance team performance. PMID:24511358

  8. Modelling of cohesive sediment dynamics in tidal estuarine systems: Case study of Tagus estuary, Portugal

    Science.gov (United States)

    Franz, G.; Pinto, L.; Ascione, I.; Mateus, M.; Fernandes, R.; Leitão, P.; Neves, R.

    2014-12-01

    Cohesive sediment dynamics in estuarine systems is a major issue in water quality and engineering problems. Numerical models can help to assess the complex dynamics of cohesive sediments, integrating the information collected in monitoring studies. Following a numerical approach we investigated the main factors that influence the cohesive sediment dynamics in an estuarine system composed of large mudflats (Tagus estuary, Portugal). After a spin up period of the bottom layer and considering the combined effect of waves and currents on the bottom shear stress, the dynamics of cohesive sediment during the fortnightly and daily erosion-sedimentation cycle was properly reproduced by the model. The results of cohesive suspended sediments were validated with data from sixteen monitoring stations located along the estuary and turbidity data measured by two multiparametric probes. The hydrodynamics were previously validated by harmonic analysis and with ADCP data. Although tidal currents are the major cause of cohesive sediment erosion, the results suggest that wind waves also play an important role. The simulated sediment mass involved in the fortnightly tidal cycle was in the same order of magnitude of the annual load from the rivers, as observed in previous studies based on field data.

  9. STRUCTURAL AND COHESION FUNDS ABSORPTION DEGREE AS AT QUARTER I 2012

    Directory of Open Access Journals (Sweden)

    Cristian Nicolae STOINA

    2012-04-01

    Full Text Available The requirements imposed by the EU, the mechanisms of the community policies, the European rules and standards are challenges that manufacturers, processors, retailers and decision makers of the Romanian economic environment must cope with. In this article the structural and cohesion funds absorption degree was analyzed on the major allocation axis: transportation, environment, regional infrastructure, human resources development, increasing economic competitiveness, administrative capacity building and technical assistance.The purpose of this paper is to attain clear conclusions, which in turn may guide us to making recommendations on the identification of weaknesses that prevent a better absorption of the funds and determination of counteracting measures for these deficiencies.Among the main findings worth mentioning is the fact that the mechanism allowing access to European fi nancing is a functional, stable and efficient one. Of course, its performance could be greatly enhanced if the producers, processors, retailers and decision makers of the Romanian economic environment, previously mentioned, would give more signifi cance to this opportunity that makes the Romanian economic development possible.

  10. High-throughput knockout screen in Schizosaccharomyces pombe identifies a novel gene required for efficient homolog disjunction during meiosis I

    OpenAIRE

    Rumpf, Cornelia; Cipak, Lubos; Novatchkova, Maria; LI, ZHANG; Polakova, Silvia; Dudas, Andrej; Kovacikova, Ines; Miadokova, Eva; Ammerer, Gustav; Gregan, Juraj

    2010-01-01

    Meiosis is the process which produces haploid gametes from diploid precursor cells. This reduction of chromosome number is achieved by two successive divisions. Whereas homologs segregate during meiosis I, sister chromatids segregate during meiosis II. To identify novel proteins required for proper segregation of chromosomes during meiosis, we applied a high-throughput knockout technique to delete 87 S. pombe genes whose expression is upregulated during meiosis and analyzed the mutant phenoty...

  11. Enhanced performance of electrostatic precipitators through chemical modification of particle resistivity and cohesion

    Energy Technology Data Exchange (ETDEWEB)

    Durham, M.D.; Baldrey, K.E.; Bustard, C.J. [ADA Technologies, Inc., Englewood, CO (United States)

    1995-11-01

    Control of fine particles, including particulate air toxics, from utility boilers is required near-term by state and federal air regulations. Electrostatic precipitators (ESP) serve as the primary air pollution control device for the majority of coal-fired utility boilers in the Eastern and Midwestern united States. Cost-effective retrofit technologies for fine particle control, including flue gas conditioning, are needed for the large base of existing ESPs. Flue has conditioning is an attractive option because it requires minimal structural changes and lower capital costs. For flue gas conditioning to be effective for fine particle control, cohesive and particle agglomerating agents are needed to reduce reentrainment losses, since a large percentage of particulate emissions from well-performing ESPs are due to erosion, rapping, and non-rapping reentrainment. A related and somewhat ironic development is that emissions reductions of SO{sub 2} from utility boilers, as required by the Title IV acid rain program of the 1990 Clean Air Act amendments, has the potential to substantially increase particulate air toxics from existing ESPs. The switch to low-sulfur coals as an SO{sub 2} control strategy by many utilities has exacerbated ESP performance problems associated with high resistivity flyash. The use of flue gas conditioning has increased in the past several years to maintain adequate performance in ESPs which were not designed for high resistivity ash. However, commercially available flue gas conditioning systems, including NH{sub 3}/SO{sub 3} dual gas conditioning systems, have problems and inherent drawbacks which create a need for alternative conditioning agents. in particular, NH{sub 3}/SO{sub 3} systems can create odor and ash disposal problems due to ammonia outgassing. In addition, there are concerns over chemical handling safety and the potential for accidental releases.

  12. A social network analysis of social cohesion in a constructed pride: implications for ex situ reintroduction of the African lion (Panthera leo.

    Directory of Open Access Journals (Sweden)

    Jackie Abell

    Full Text Available Animal conservation practices include the grouping of captive related and unrelated individuals to form a social structure which is characteristic of that species in the wild. In response to the rapid decline of wild African lion (Panthera leo populations, an array of conservational strategies have been adopted. Ex situ reintroduction of the African lion requires the construction of socially cohesive pride structures prior to wild release. This pilot study adopted a social network theory approach to quantitatively assess a captive pride's social structure and the relationships between individuals within them. Group composition (who is present in a group and social interaction data (social licking, greeting, play was observed and recorded to assess social cohesion within a released semi-wild pride. UCINET and SOCPROG software was utilised to represent and analyse these social networks. Results indicate that the pride is socially cohesive, does not exhibit random associations, and the role of socially influential keystone individuals is important for maintaining social bondedness within a lion pride. These results are potentially informative for the structure of lion prides, in captivity and in the wild, and could have implications for captive and wild-founder reintroductions.

  13. A social network analysis of social cohesion in a constructed pride: implications for ex situ reintroduction of the African lion (Panthera leo).

    Science.gov (United States)

    Abell, Jackie; Kirzinger, Morgan W B; Gordon, Yvonne; Kirk, Jacqui; Kokeŝ, Rae; Lynas, Kirsty; Mandinyenya, Bob; Youldon, David

    2013-01-01

    Animal conservation practices include the grouping of captive related and unrelated individuals to form a social structure which is characteristic of that species in the wild. In response to the rapid decline of wild African lion (Panthera leo) populations, an array of conservational strategies have been adopted. Ex situ reintroduction of the African lion requires the construction of socially cohesive pride structures prior to wild release. This pilot study adopted a social network theory approach to quantitatively assess a captive pride's social structure and the relationships between individuals within them. Group composition (who is present in a group) and social interaction data (social licking, greeting, play) was observed and recorded to assess social cohesion within a released semi-wild pride. UCINET and SOCPROG software was utilised to represent and analyse these social networks. Results indicate that the pride is socially cohesive, does not exhibit random associations, and the role of socially influential keystone individuals is important for maintaining social bondedness within a lion pride. These results are potentially informative for the structure of lion prides, in captivity and in the wild, and could have implications for captive and wild-founder reintroductions. PMID:24376544

  14. Social cohesion, social participation and HIV testing among men who have sex with men in Swaziland.

    Science.gov (United States)

    Grover, Elise; Grosso, Ashley; Ketende, Sosthenes; Kennedy, Caitlin; Fonner, Virginia; Adams, Darrin; Sithole, Bhekie; Mnisi, Zandile; Maziya, Sibusiso Lulu; Baral, Stefan

    2016-06-01

    Social cohesion and social participation are social factors that may help reduce HIV risks and optimize health-seeking behaviors. We examined the association between these factors and HIV testing in the last 12 months among men who have sex with men (MSM) in Swaziland using a cross-sectional survey conducted with 326 men, 18 years of age or older reporting having sex with another man in the last 12 months. Social capital analyses included measures of social cohesion and social participation. The social cohesion measurement scale was created through exploratory factor analysis using polychoric correlations to determine unidimensionality and Cronbach's Alpha to assess internal consistency. The measurement scale was divided at the 25th and 75th percentiles using "high," "medium" and "low" levels of social cohesion for between-group comparisons. The social participation index included four questions regarding participation, resulting in a participation index ranging from 0 to 4. In the final multivariate logistic regression model, an increase in the level of social participation was found to be significantly associated with HIV testing in the last 12 months, adjusting for age, income, reporting a casual partner, family exclusion and rejection by other MSM due to sexual orientation (adjusted odds ratio [aOR]: 1.3, 95% confidence interval [CI] 1.1-1.7, p cohesion had almost twice the odds of HIV testing in the last 12 months (aOR: 1.8, 95% CI 1.1-3.3, p cohesion, though the overall social cohesion variable was not found to be significant using a Wald test in either the adjusted or unadjusted logistic regression models. These data suggest that building solidarity and trust within and between groups may be a strategy to improve uptake of HIV testing. PMID:26824888

  15. Cohesive Devices in English%英语中的衔接理论研究

    Institute of Scientific and Technical Information of China (English)

    陈晓波

    2012-01-01

    In linguistics fields, cohesion has become one of the major elements in discourse analysis, and cohesion theory has gained more and more attention. Cohesion is the foundation of coherence and plays a vital role in creating texture. Cohesion is the foundation of discourse coherence and plays a crucial role in constructing the text. Since 1976, Halliday and Hasan proposed the term of cohesion for the first time, many linguists and scholars have studied cohesion systematically, resulting in a series of compre- hensive theory, but there have been many different views. This paper reviews the research of many domestic and foreign scholars on the cohesion theory , and put forward my own views.%在语言学领域,衔接理论已经获得了越来越多的关注。衔接已成为话语分析中的主要元素之一。衔接是语篇连贯的基础,在构建文本上起着至关重要的作用,自从1976年英国语言学家韩礼德和哈桑首次给出衔接的概念以来,很多的语言学家和学者对衔接都进行过系统的研究,产生了一系列比较全面的理论,但是也出现了很多不同的看法。

  16. Social Cohesion between the Member States of the European Union: Past Developments and Prospects for an Enlarged Union

    OpenAIRE

    Berger-Schmitt, Regina

    2002-01-01

    The economic & social cohesion of Europe constitutes a main policy goal of the European Union. In this article a broad concept of social cohesion is proposed, which covers two principal dimensions: in addition to disparities in living conditions, which can be called the inequality dimension of social cohesion, social ties between countries are another important aspect, designated in brief as the social capital dimension. For both dimensions empirical analyses of selected indicators are presen...

  17. Probabilistic method for geotechnical design. Application to cohesive soils; Metodo probabilista de diseno geotecnico. Aplicacion en Suelos Cohesivos

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Rodriguez, A. J.; Quevedo Sotolongo, G.

    2012-07-01

    A methodology to carry out a process of stochastic modelling in the calculation of the bearing capacity of a strip footing, on a purely cohesive soil, is proposed. the mentioned modelling is based on the application of Monte Carlo Simulation, which is more efficient, in terms of results, than classic procedures using deterministic models. These results will be the base for the application of a probabilistic design method, specifically the safety theory, starting by a statistical characterization of every random variables the impact in the problem, and it defines as a final result, a safety level for the structure, whose value will be the nearest to required safety in first limit state design or stability limit state, which is equivalent to 0.98. By this way it is established the design point of the structure according to safety design condition. (Author) 9 refs.

  18. Income inequality, social cohesion, and class relations: a critique of Wilkinson's neo-Durkheimian research program.

    Science.gov (United States)

    Muntaner, C; Lynch, J

    1999-01-01

    Wilkinson's "income inequality and social cohesion" model has emerged as a leading research program in social epidemiology. Public health scholars and activists working toward the elimination of social inequalities in health can find several appealing features in Wilkinson's research. In particular, it provides a sociological alternative to former models that emphasize poverty, health behaviors, or the cultural aspects of social relations as determinants of population health. Wilkinson's model calls for social explanations, avoids the subjectivist legacy of U.S. functionalist sociology that is evident in "status" approaches to understanding social inequalities in health, and calls for broad policies of income redistribution. Nevertheless, Wilkinson's research program has characteristics that limit its explanatory power and its ability to inform social policies directed toward reducing social inequalities in health. The model ignores class relations, an approach that might help explain how income inequalities are generated and account for both relative and absolute deprivation. Furthermore, Wilkinson's model implies that social cohesion rather than political change is the major determinant of population health. Historical evidence suggests that class formation could determine both reductions in social inequalities and increases in social cohesion. Drawing on recent examples, the authors argue that an emphasis on social cohesion can be used to render communities responsible for their mortality and morbidity rates: a community-level version of "blaming the victim." Such use of social cohesion is related to current policy initiatives in the United States and Britain under the New Democrat and New Labor governments. PMID:10079398

  19. A cohesive zone model for the electromechanical damage of piezoelectric/ferroelectric materials

    International Nuclear Information System (INIS)

    A numerical fracture analysis of piezoelectric and ferroelectric materials is conducted using an advanced exponential cyclic cohesive zone model. The implemented irreversible cohesive law allows for the damage accumulation during subcritical electromechanical loading. Change in polarization direction (as a result of ferroelectric domain switching) due to applied electromechanical loading is taken into account. A generalized capacitor model representing the permittivity of the grain boundaries or cohesive elements is implemented in the cohesive law. Due to the presence of cohesive elements, a specimen can experience instability of the equilibrium response path. Therefore, post-peak strain-softening constitutive relations are investigated to handle the snapback effect. Numerical simulations are performed for a 3D basic test model as well as for a ferroelectric actuator. The observed results reflect a realistic influence of the electric field as well as domain switching on the fracture of the specimen. Mechanisms of damage initiation and accumulation are illustrated in the piezoelectric/ferroelectric medium under cyclic electric loading. (paper)

  20. Effects of Cohesion-Based Feedback on the Collaborations in Global Software Development Teams

    Directory of Open Access Journals (Sweden)

    Alberto Castro-Hernández

    2015-12-01

    Full Text Available This paper describes a study that examines the effect of cohesion-based feedback on a team member’s behaviors in a global software development project. Chat messages and forum posts were collected from a software development project involving students living in the US and Mexico. Half of the teams in the project received feedback in the form of a graphical representation that displayed the group’s cohesion level, while the other teams received no feedback. The nature of the group interactions as well as the linguistic content of such interactions was then analyzed and compared. Results from this analysis show statistically significant differences between the feedback and non-feedback c onditions. More s pecifically, cohesion-based feedback had a positive relation to a team’s total message count, response rate, and individual cohesion score. In addition, the analysis of linguistic categories showed that the most salient categories observed were related to words about time and work. Furthermore, a comparison between feedback variables and type (i.e., positive and negative feedback indicates that those individuals exposed to negative feedback had an increase in their communication pacing rates when exposed to positive feedback. Although the feedback system did not appear to affect individual performance, the findings s u ggest t h at t h e c o hesion m e asure d e fined in th is st ud y is positively correlated to the task cohesion construct and is also related to individual and team performance.