56,818 research outputs found
1ST MEASUREMENT OF GAMMA(D(S)(+)-]MU+NU)/GAMMA(D(S)(+)-]PHI-PI+)
No full textComplete Author List:
ACOSTA D, ATHANAS M, MASEK G, PAAR H, BEAN A, GRONBERG J, KUTSCHKE R, MENARY S, MORRISON RJ, NAKANISHI S, NELSON HN, NELSON TK, RICHMAN JD, RYD A, TAJIMA H, SCHMIDT D, SPERKA D, WITHERELL MS, PROCARIO M, YANG S, BALEST R, CHO K, DAOUDI M, FORD WT, JOHNSON DR, LINGEL K, LOHNER M, RANKIN P, SMITH JG, ALEXANDER JP, BEBEK C, BERKELMAN K, BESSON D, BROWDER TE, CASSEL DG, CHO HA, COFFMAN DM, DRELL PS, EHRLICH R, GALIK RS, GARCIASCIVERES M, GEISER B, GITTELMAN B, GRAY SW, HARTILL DL, HELTSLEY BK, JONES CD, JONES SL, KANDASWAMY J, KATAYAMA N, KIM PC, KREINICK DL, LUDWIG GS, MASUI J, MEVISSEN J, MISTRY NB, NG CR, NORDBERG E, OGG M, PATTERSON JR, PETERSON D, RILEY D, SALMAN S, SAPPER M, WORDEN H, WURTHWEIN F, AVERY P, FREYBERGER A, RODRIGUEZ J, STEPHENS R, YELTON J, CINABRO D, HENDERSON S, KINOSHITA K, LIU T, SAULNIER M, SHEN F, WILSON R, YAMAMOTO H, ONG B, SELEN M, SADOFF AJ, AMMAR R, BALL S, BARINGER P, COPPAGE D, COPTY N, DAVIS R, HANCOCK N, KELLY M, KWAK N, LAM H, KUBOTA Y, LATTERY M, NELSON JK, PATTON S, PERTICONE D, POLING R, SAVINOV V, SCHRENK S, WANG R, ALAM MS, KIM IJ, NEMATI B, ONEILL JJ, SEVERINI H, SUN CR, ZOELLER MM, CRAWFORD G, DAUBENMIER CM, FULTON R, FUJINO D, GAN KK, HONSCHEID K, KAGAN H, KASS R, LEE J, MALCHOW R, MORROW F, SKOVPEN Y, SUNG M, WHITE C, WHITMORE J, WILSON P, BUTLER F, FU X, KALBFLEISCH G, LAMBRECHT M, ROSS WR, SKUBIC P, SNOW J, WANG PL, WOOD M, BORTOLETTO D, BROWN DN, FAST J, MCILWAIN RL, MIAO T, MILLER DH, MODESITT M, SCHAFFNER SF, SHIBATA EI, SHIPSEY IPJ, WANG PN, BATTLE M, ERNST J, KROHA H, ROBERTS S, SPARKS K, THORNDIKE EH, WANG CH, DOMINICK J, SANGHERA S, SHELKOV V, SKWARNICKI T, STROYNOWSKI R, VOLOBOUEV I, ZADOROZHNY P, ARTUSO M, HE D, GOLDBERG M, HORWITZ N, KENNETT R, MONETI GC, MUHEIM F, MUKHIN Y, PLAYFER S, ROZEN Y, STONE S, THULASIDAS M, VASSEUR G, ZHU G, BARTELT J, CSORNA SE, EGYED Z, JAIN V, SHELDON P, AKERIB DS, BARISH B, CHADHA M, CHAN S, COWEN DF, EIGEN G, MILLER JS, OGRADY C, URHEIM J, WEINSTEIN A
HIV Prevention and Social Desirability: Husband–Wife Discrepancies in Reports of Condom Use
No full textReferencias bibliográficas:
• Ali, M. M., Cleland, J. G., & Carael, M. (2001). Sexual risk behavior in urban populations of northeastern Africa. AIDS and Behavior, 5, 343-352.
• Anglewicz, P., Adams, J., Obare, F., Kohler, H.-P., & Watkins, S. (2009). The Malawi Diffusion and Ideational Change Project 2004-06: Data collection, data quality and analysis of attrition. Demographic Research, 20, 503-540.
• Anglewicz, P. A., Bignami-Van Assche, S., Clark, S., & Mkandawire, J. (2010). HIV risk among currently married couples in rural Malawi: What do spouses know about each other? AIDS and Behavior, 14, 103-112.
• Bankole, A., Ahmed, F. H., Neema, S., Ouedraogo, C., & Konyani, S. (2007). Knowledge of correct condom use and consistency of use among adolescents in four countries in sub-Saharan Africa. African Journal of Reproductive Health,
11, 197-220.
• Barden-O'Fallon, J. L., deGraft-Johnson, J., Bisika, T., Sulzbach, S., Benson, A., & Tsui, A. O. (2004). Factors associated with HIV/AIDS knowledge and risk perception in rural Malawi. AIDS and Behavior, 8, 131-140.
• Bicchieri, C. (2006). The grammar of society: The nature and dynamics of social norms. New York: Cambridge University Press.
• Breen, R. (2000). Why is support for extreme parties underestimated by surveys? A latent class analysis. British Journal of Political Science, 30, 375-382.
• Bühler, C. & Kohler, H.-P. (2003). Talking about AIDS: The influence of communication networks on individual risk perceptions of HIV/AIDS infections and favored protective behaviors in South Nyanza District, Kenya. Demographic
Research Special Collection, 1, 397-438.
• Caldwell, J. C. (2000). Rethinking the African AIDS epidemic. Population and Development Review, 26, 117-135.
• Chimbiri, A. M. (2007). The condom is an "intruder" in marriage: Evidence from rural Malawi. Social Science & Medicine, 64, 1102-1115.
• Cleland, J., & Ali, M. M. (2006). Sexual abstinence, contraception, and condom use by young African women: A secondary analysis of survey data. The Lancet, 368, 1788-1793.
• Crowne, D. P., & Marlowe, D. A. (1960). A new scale of social desirability independent of psychopathology. Journal of Consulting Psychology, 24, 349-354.
• DeMaio, T. J. (1984). Social desirability and survey measurement: A review. In C. F. Turner & E. Martin (Eds.), Surveying subjective phenomena (pp. 257-282). New York: Russell Sage Foundation.
• de Walque, D. (2007). Sero-discordant couples in five African countries: Implications for prevention strategies. Population and Development Review, 33, 501-523.
• Dinkelman, T., & Lam, D. (2009). A model for understanding gender discrepancies in sexual behavior reports. Research Report No. 09-669, Population Studies Center, University of Michigan.
• Dunkle, K., Stephenson, R., Karita, E., Chomba, E., Kayitenkore, K., Vwalika, C., Greenberg, L., & Allen, S. (2008). New heterosexually transmitted HIV in married or cohabiting couples in urban Zambia and Rwanda: An analysis of survey
and clinical data. The Lancet, 371, 2183-2191.
• Feyisetan, B. (2000). Spousal communication and contraceptive use among the Yoruba of Nigeria. Population Research and Policy Review, 19, 29-45.
• Fowler, F. J. (1993). Survey research methods. Newbury Park, CA: Sage.
• Gelmon, L., Kenya, P., Oguya, F., Cheluget, B., & Haile, G. (2009). Kenya HIV prevention response and modes of transmission analysis. Nairobi, Kenya: National AIDS Control Council.
• Gillespie, S., Kadiyala, S., & Greener, R. (2007). Is poverty or wealth driving HIV transmission? AIDS, 21, 5-16.
• Gregson, S., Zhuwau, T., Ndlovu, J., & Nyamukapa, C. (2002). Methods to reduce social desirability bias in sex surveys in low-development settings. Sexually Transmitted Diseases, 29, 568-575.
• Hagenaars, J. A. (1993). Loglinear models with latent variables. Newbury Park, CA: Sage.
• Hagenaars, J. A., & McCutcheon, A. (2002). Applied latent class analysis. Newbury Park, CA: Sage.
• Hargreaves, J. R., Bonell, C. P., Boler, T., Boccia, D., Birdthistle, I., Fletcher, A., Pronyk, P. M., & Glynn, J. R. (2008). Systematic review exploring time trends in the association between educational attainment and risk of HIV infection in
sub-Saharan Africa. AIDS, 22, 403-414.
• Harvey, S. M., Bird, S. T., Henderson, J. T., Beckman, L. J., & Huszti, H. C. (2004). He said, she said: Concordance between sexual partners. Sexually Transmitted Diseases, 31, 185-191.
• Helleringer, S., & Kohler, H.-P. (2005). Social networks, perceptions of risk, and changing attitudes towards HIV/AIDS: New evidence from a longitudinal study using fixed-effects analysis. Population Studies, 59, 265-282.
• Huygens, P., Kajura, E., Seeley, J., & Barton, T. (1996). Rethinking methods for the study of sexual behaviour. Social Science & Medicine, 42, 221-231.
• Kissinger, P., Rice, J., Farly, T., Trim, S., Jewitt, K., Margavio, V., & Martin, D. H. (1999). Application of computer-assisted interviews to sexual behavior research. American Journal of Epidemiology, 149, 950-954.
• Lamberts, K., & Shanks, D. (1997). Knowledge, concepts, and categories. Hove, UK: Psychology Press.
• Lindan, C., Allen, S., Carael, M., Nsengumuremyi, F., Van de Perre, P., Serufilira, A., Tice, J., Black, D., Coates, T., & Hulley, S. (1991). Knowledge, attitudes, and perceived risk of AIDS among urban Rwandan women: Relationship to HIV
infection and behavior change. AIDS, 5, 993-1002.
• Malawi Demographic and Health Survey. (2000). Calverton, MD: National Statistical Office (Malawi) and ORC Macro.
• Malawi Demographic and Health Survey. (2004). Calverton, MD: National Statistical Office (Malawi) and ORC Macro.
• McCutcheon, A. (1987). Latent class analysis. Newbury Park, CA: Sage.
• Miller, K., Zulu, E. M., & Watkins, S. C. (2001). Husband-wife survey responses in Malawi. Studies in Family Planning, 32, 161-174.
• Morris, M., & Kretzschmar, M. (1995). Concurrent partnerships and transmission dynamics in networks. Social Networks, 17, 299-318.
• Morris, M., & Kretzschmar, M. (1997). Concurrent partnerships and the spread of HIV. AIDS, 11, 641-648.
• Nachega, J. B., Lehman, D. A., Hlatshwayo, D., Mothopeng, R., Chaisson, R. E., & Karstaedt, A. S. (2005). HIV/AIDS and antiretroviral treatment knowledge, attitudes, beliefs, and practices in HIV-infected adults in Soweto, South Africa.
Journal of Acquired Immune Deficiency Syndromes, 38, 196-201.
• Neequaye, A. R., Neequaye, J. E., & Biggar, R. J. (1991). Factors that could influence the spread of AIDS in Ghana, West Africa: Knowledge of AIDS, sexual behavior, prostitution, and traditional medical practices. Journal of Acquired
Immune Deficiency Syndromes, 4, 914-919.
• Phillips, D. L., & Clancy, K. J. (1972). Some effects of "social desirability" in survey studies. American Journal of Sociology, 77, 921-940.
• Reniers, G. (2008). Marital strategies for regulating exposure to HIV. Demography, 45, 417-438.
• Smith, D. J. (2006). Love and the risk of HIV: Courtship, marriage and infidelity in southeastern Nigeria. In J. Hirsch & H. Wardlow (Eds.), Modern loves: The anthropology of romantic courtship and companionate marriage (pp. 137-153).
Ann Arbor: University of Michigan Press.
• Smith, K., & Watkins, S. C. (2005). Perceptions of risk and strategies for prevention: Responses to HIV/AIDS in rural Malawi. Social Science & Medicine, 60, 649-660.
• Takyi, B. K., & Gyimah, S. O. (2007). Matrilineal family ties and marital dissolution in Ghana. Journal of Family Issues, 28, 682-705.
• Tavory, I., & Swidler, A. (2009). Condom semiotics: Meaning and condom use in rural Malawi. American Sociological Review, 74, 171-189.
• Tawfik, L. (2003). Soap, sweetness, and revenge: Patterns of sexual onset and partnerships amidst AIDS in rural Southern Malawi (Unpublished doctoral dissertation). Johns Hopkins University, Baltimore.
• Tawfik, L., & Watkins, S. C. (2007). Sex in Geneva, sex in Lilongwe, and sex in Balaka. Social Science & Medicine, 64, 1090-1101.
• UNAIDS & World Health Organization. (2007). AIDS epidemic update. Geneva, Switzerland: Authors.
• UNAIDS & World Health Organization. (2008). Report on the global AIDS epidemic. Geneva, Switzerland: Authors.
• UNAIDS & World Health Organization. (2009). UNAIDS annual report 2008: Towards universal access. Geneva, Switzerland: Authors.
• Vermunt, J. K. (1997). LEM: A general program for the analysis of categorical data [Computer software]. Department of Methodology and Statistics, Tilburg University, Tilburg, The Netherlands.
• Watkins, S. C. (2004). Navigating the AIDS epidemic in rural Malawi. Population and Development Review, 30, 673-705.
• Watkins, S., Behrman, P., Kohler, H.-P., & Zulu, E. M. (2003) Introduction to "Research on Demographic Aspects of HIV/AIDS in Rural Africa." Demographic Research, Special Collection, 1, 1-30.
• Westercamp, N., Matsson, C. L., Madonia, M., Moses, S., Agot, K., Ndinya-Achola, J. O., Otieno, E., Ouma, N., & Bailey, R. C. (2010). Determinants of consistent condom use vary by partner type among young men in Kisumu, Kenya: A
multi-level data analysis. AIDS and Behavior, 14, 949-959.
• World Bank. (2006). Malawi at a glance. Retrieved from.
• Zulu, E. M., & Chepngeno, G. (2003). Spousal communication about the risk of contracting HIV/AIDS in rural Malawi. Demographic Research, Special Collection, 1, 247-277.
•Resumen:
Greater use of condoms within marriage would help limit the spread of HIV in sub-Saharan Africa. Using data from the Malawi Diffusion and Ideational Change Project (MDICP), the authors examined the influence that the fidelity norm and the traditional association between marriage and reproduction have on condom use with a spouse. The sample included 749 married couples. The authors used latent class analysis to estimate a "true," or latent measure of condom use by couples based on the individual reports of husbands and wives and to explore the reasons why individuals tend to misreport their use of condoms. They found that married couples with more children were more likely to use condoms and that having been informed by experts about AIDS prevention at home induced men and women to overreport condom use within marriage in a survey but may not necessarily increase the extent to which condoms are used.Depto. de Sociología AplicadaFac. de EducaciónTRUEpu
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
Exclusive and inclusive semileptonic decays of B mesons to D mesons
No full textcomplete author list: Fulton R.; Jensen T.; Johnson D.; Kagan H.; Kass R.; Morrow F.; Whitmore J.; Wilson P.; Bortoletto D.; Chen W.; Dominick J.; McIlwain R.; Miller D.; Ng C.; Schaffner S.; Shibata E.; Shipsey I.; Yao W.; Battle M.; Sparks K.; Thorndike E.; Wang C.; Alam M.; Kim I.; Li W.; Romero V.; Sun C.; Wang P.; Zoeller M.; Goldberg M.; Haupt T.; Horwitz N.; Jain V.; Mestayer M.; Moneti G.; Rozen Y.; Rubin P.; Sharma V.; Skwarnicki T.; Thulasidas M.; Zhu G.; Csorna S.; Letson T.; Alexander J.; Artuso M.; Bebek C.; Berkelman K.; Browder T.; Cassel D.; Cheu E.; Coffman D.; Crawford G.; Dewire J.; Drell P.; Ehrlich R.; Galik R.; Garcia-Sciveres M.; Geiser B.; Gittelman B.; Gray S.; Halling A.; Hartill D.; Heltsley B.; Honscheid K.; Kandaswamy J.; Katayama N.; Kreinick D.; Lewis J.; Ludwig G.; Masui J.; Mevissen J.; Mistry N.; Nandi S.; Nordberg E.; O'Grady C.; Peterson D.; Pisharody M.; Riley D.; Sapper M.; Selen M.; Silverman A.; Stone S.; Worden H.; Worris M.; Sadoff A.; Avery P.; Besson D.; Garren L.; Yelton J.; Kinoshita K.; Pipkin F.; Procario M.; Wilson R.; Wolinski J.; Xiao D.; Zhu Y.; Ammar R.; Baringer P.; Coppage D.; Davis R.; Haas P.; Kwak N.; Lam H.; Ro S.; Kubota Y.; Nelson J.; Perticone D.; Poling R.; Fulton R.; Poling R.; Perticone D.; Nelson J.; Fulton R.</p
International lessons for the digital age
No full textSome commentators hold the view that the digital divide is a problem largely caused by lack of access to appropriate technologies which, when overcome, will act as a virtual panacea for many interlinked ills. Yet, others see this as far too simplistic an analysis in the search for radical solutions in a world of such extreme social inequality and global inequity. This paper will argue for a bottom-up rather than a top-down approach to finding those solutions, advocating a greater amount of needs-based work in this field, getting to the root of the problem by taking into account the particular set of conditions within each situation or case study. At the same time it will strive to create a more harmonious world view where each small scale project is seen as part of a network searching for broader solutions rather than an end product in themselves. In order to provide a framework for this argument, and support theories with informed practice, a case study of a teacher training project delivered to Rwandan students, through the medium of the English language and new technologies, will be used as an example of what has been achieved so far in the field of online learning, and what lessons could be learned for the future. The paper shall also argue for greater involvement on the part of British universities, so that voyages into this multidimensional terrain, widely explored but largely uncharted, remain more pedagogic than economi
Erosie door open taludbekledingen. Samenvattend verslag + Bijlage A t/m D
No full textOpen taludbekledingen die bestaan uit in verband geplaatste betonblokken met gaten, bieden de mogelijkheid vegetatie te doen groeien, waardoor mogelijk een milieuvriendelijke oever kan worden verkregen. In het pioniersstadium van de vegetatie is het evenwel ongewenst dat de gatvulling uitspoelt. Teneinde de relatie tussen waterbeweging en erosie van de gatvulling vast te stellen, is door de Dienst Weg- en Waterbouwkunde van Rijkswaterstaat per brief d.d. 16 maart 1987 (kenmerk WB 570), opdracht verleend aan het Waterloopkundig Laboratorium tot het uitvoeren van onderzoek naar de erosie door open taludbekledingen. Het doel van het onderzoek is het ontwikkelen van ontwerprichtlijnen voor taludbekledingen met gaten die groter zijn dan de zand- of filterkorrels eronder. Hiertoe dient de kritieke waterbeweging bij een oever- of dijkbekleding te worden vastgesteld, waarbij nog toelaatbare erosie is te verwachten. De toelaatbare erosie mag daarbij maximaal gelijk zijn aan de hoeveelheid sediment in de gaten. Filter- of basismateriaal gelegen onder de elementen mag dus niet uitspoelen. Bij oeverbekledingen waar vegetatie een rol moet gaan spelen, is de toelaatbare erosie kleiner, dat wil zeggen in de gaten dient sediment achter te blijven.Steenzettingen - TAW/EN
Measurement of the B̄→D*lν̄ branching fractions and -Vcb-
No full textcomplete author list:
Barish B.; Chadha M.; Chan S.; Cowen D.; Eigen G.; Miller J.; O'Grady C.; Urheim J.; Weinstein A.; Acosta D.; Athanas M.; Masek G.; Paar H.; Gronberg J.; Kutschke R.; Menary S.; Morrison R.; Nakanishi S.; Nelson H.; Nelson T.; Qiao C.; Richman J.; Ryd A.; Tajima H.; Sperka D.; Witherell M.; Procario M.; Balest R.; Cho K.; Daoudi M.; Ford W.; Johnson D.; Lingel K.; Lohner M.; Rankin P.; Smith J.; Alexander J.; Bebek C.; Berkelman K.; Bloom K.; Browder T.; Cassel D.; Cho H.; Coffman D.; Crowcroft D.; Drell P.; Ehrlich R.; Gaidarev P.; Galik R.; Garcia-Sciveres M.; Geiser B.; Gittelman B.; Gray S.; Hartill D.; Heltsley B.; Jones C.; Jones S.; Kandaswamy J.; Katayama N.; Kim P.; Kreinick D.; Ludwig G.; Masui J.; Mevissen J.; Mistry N.; Ng C.; Nordberg E.; Patterson J.; Peterson D.; Riley D.; Salman S.; Sapper M.; Würthwein F.; Avery P.; Freyberger A.; Rodriguez J.; Yang S.; Yelton J.; Cinabro D.; Henderson S.; Liu T.; Saulnier M.; Wilson R.; Yamamoto H.; Bergfeld T.; Eisenstein B.; Gollin G.; Ong B.; Palmer M.; Selen M.; Thaler J.; Edwards K.; Ogg M.; Bellerive A.; Britton D.; Hyatt E.; MacFarlane D.; Patel P.; Spaan B.; Sadoff A.; Ammar R.; Ball S.; Baringer P.; Bean A.; Besson D.; Coppage D.; Copty N.; Davis R.; Hancock N.; Kelly M.; Kotov S.; Kravchenko I.; Kwak N.; Lam H.; Kubota Y.; Lattery M.; Momayezi M.; Nelson J.; Patton S.; Perticone D.; Poling R.; Savinov V.; Schrenk S.; Wang R.; Alam M.; Kim I.; Nemati B.; Ling Z.; O'Neill J.; Severini H.; Sun C.; Wappler F.; Crawford G.; Daubenmier C.; Fulton R.; Fujino D.; Gan K.; Honscheid K.; Kagan H.; Kass R.; Lee J.; Malchow R.; Skovpen Y.; Sung M.; White C.; Zoeller M.; Butler F.; Fu X.; Kalbfleisch G.; Ross W.; Skubic P.; Wood M.; Fast J.; Mcilwain R.; Miao T.; Miller D.; Modesitt M.; Payne D.; Shibata E.; Shipsey I.; Wang P.; Battle M.; Ernst J.; Gibbons L.; Kwon Y.; Roberts S.; Thorndike E.; Wang C.; Dominick J.; Lambrecht M.; Sanghera S.; Shelkov V.; Skwarnicki T.; Stroynowski R.; Volobouev I.; Wei G.; Zadorozhny P.; Artuso M.; Goldberg M.; He D.; Horwitz N.; Kennett R.; Mountain R.; Moneti G.; Muheim F.; Mukhin Y.; Playfer S.; Rozen Y.; Stone S.; Thulasidas M.; Vasseur G.; Xing X.; Zhu G.; Bartelt J.; Csorna S.; Egyed Z.; Jain V.; Gibaut D.; Kinoshita K.; Kinoshita K.; Barish B
Measurement of the D+/- production asymmetry in 7 TeV pp collisions
No full textThe asymmetry in the production cross-section \sigma of D+/- mesons, A_P = (\sigma(D+) - \sigma(D-))/(\sigma(D+) + \sigma(D-)), is measured in bins of pseudorapidity \eta and transverse momentum p_T within the acceptance of the LHCb detector. The result is obtained with a sample of D+ -> K_S pi+ decays corresponding to an integrated luminosity of 1.0 fb^-1, collected in pp collisions at a centre of mass energy of 7 TeV at the Large Hadron Collider. When integrated over the kinematic range 2.0 K_S pi+ decay is negligible. No significant dependence on \eta or p_T is observed
Evidence for the decay B0→J/ψω and measurement of the relative branching fractions of meson decays to J/ψη and J/ψη′
No full textFirst evidence of the B 0 → J / ψ ω decay is found and the B s 0 → J / ψ η and B s 0 → J / ψ η ′ decays are studied using a dataset corresponding to an integrated luminosity of 1.0 fb -1 collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV. The branching fractions of these decays are measured relative to that of the B 0 → J / ψ ρ 0 decay:frac(B (B 0 → J / ψ ω), B (B 0 → J / ψ ρ 0)) = 0.89 ± 0.19 (stat) - 0.13 + 0.07 (syst),frac(B (B s 0 → J / ψ η), B (B 0 → J / ψ ρ 0)) = 14.0 ± 1.2 (stat) - 1.5 + 1.1 (syst) - 1.0 + 1.1 (frac(f d, f s)),frac(B (B s 0 → J / ψ η ′), B (B 0 → J / ψ ρ 0)) = 12.7 ± 1.1 (stat) - 1.3 + 0.5 (syst) - 0.9 + 1.0 (frac(f d, f s)), where the last uncertainty is due to the knowledge of f d / f s, the ratio of b-quark hadronization factors that accounts for the different production rate of B 0 and B s 0 mesons. The ratio of the branching fractions of B s 0 → J / ψ η ′ and B s 0 → J / ψ η decays is measured to befrac(B (B s 0 → J / ψ η ′), B (B s 0 → J / ψ η)) = 0.90 ± 0.09 (stat) - 0.02 + 0.06 (syst)
Assessing late-time singular behaviour in symmetry-plane models of 3D Euler flow
No full textMotivated by work on stagnation-point type exact solutions of the 3D Euler fluid equations by Gibbon [Gibbon et. al. Phys. D, 132, 497, (1999)] and the subsequent demonstration of finite-time blowup by Constantin [Constantin, Math. Res. Notices, 9, 455, (2000)] we introduce a one-parameter family of models of the 3D Euler equations on a 2D symmetry plane. These models provide a collection of blow-up scenarios which admit analytical solutions and are computationally inexpensive in comparison to the full 3D Euler equations. We take advantage of these features to examine the efficacy of novel methods which aid the assessment of finite-time blow-up in numerical simulations. The principal of these is the mapping to regular systems [Bustamante, Phys. D, 240, 1092, (2011)]; a bijective nonlinear mapping of time and the prognostic variables based on a Beale-Kato-Majda (BKM) type supremum norm regularity condition [Beale et. al. Commun. Math. Phys. 94, 61, (1984)]. We show a 3 order of magnitude increase of accuracy of the singularity time when employing the mapping with negligible additional computational expense. An investigation of the spectra of the primary field (vortex stretching rate) allows us to confirm a power law decrement of the analyticity-strip width with time in agreement with rigorous bounds bridging between the global spatial behaviour and BKM theorems [Bustamante & Brachet, Phys. Rev. E. 86, (2012)]
- …
