7 results on '"C. Markus"'
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2. Search for massive, unstable photinos that violate R parity
- Author
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R. Bartoldus, C. Y. Chang, M. F. Turner, H. O. Ogren, S. W. O'Neale, K. J. Anderson, B. C. Shen, Christoph Geich-Gimbel, M. Yurko, G. Beaudoin, P. Poffenberger, James Pinfold, C. Moisan, G. A. Beck, H. Mes, I. P. Duerdoth, Erez Etzion, D. Axen, A. Jawahery, Silvia Arcelli, D. G. Fong, J. Gascon, H. von der Schmitt, A. K. Honma, P. W. Jeffreys, Stefan Kluth, M. Jones, Richard Keeler, Shlomit Tarem, Gideon Bella, W. G. Scott, G. Giacomelli, G. T. Zorn, Shlomo Dado, S. L. Chu, R. Kowalewski, Otmar Biebel, Peter Sherwood, G. E. Richards, J. Hart, T. J. Smith, Achim Stahl, P. Teixeira-Dias, R. W. Springer, Alexander Wagner, J. D. Gillies, R.J. Akers, B. Schmitt, J. W. Gary, H. J. Burckhart, Jacqueline Batley, J. C. Clayton, R. J. Barlow, J. Kroll, P. Schenk, O. Schaile, J. Hagemann, J. Ludwig, K. Runge, P. Bock, P. Igo-Kemenes, A. M. Rossi, T. Tsukamoto, S. Levegrün, Marcello Mannelli, J. E. Duboscq, P. Bright-Thomas, H. Jeremie, D. J. Miller, S. Rossberg, C. J. Oram, M. J. Losty, F. X. Gentit, X. C. Lou, Giora Mikenberg, C. Jui, J. E. Conboy, D. G. Charlton, D. L. Wagner, M. S. Dixit, Frans Meijers, P. Mättig, Claude Leroy, J. P. Pansart, U. Maur, I. J. Bloodworth, R. P. Middleton, H. Deng, R. Humbert, N. I. Geddes, A. Pouladdej, F. Odorici, R. Lahmann, J. G. Layter, M. Hansroul, P. Scharff-Hansen, D. A. Hinshaw, D. C. Imrie, J. Goldberg, B. Boden, B. Poli, Gregor Herten, J. M. Roney, M. Settles, Norbert Wermes, A. D. Schaile, Sherry Towers, T. Kawamoto, B. Nellen, F. S. Merritt, C. Wahl, M. Morii, E. do Couto e Silva, M. Foucher, C. H. Shepherd-Themistocleous, Tohru Takeshita, H. M. Fischer, G. A. Snow, B. Wilkens, C. P. Ward, A. M. Smith, H. Takeda, P. Leblanc, John Hobbs, Peter R Hobson, S. Orito, M. Rosvick, R. J. Homer, A. Michelini, A. C. Janissen, D. L. Rees, F. G. Oakham, Madjid Boutemeur, G. W. Wilson, V. H. Winterer, T. Behnke, R. Mir, G. P. Siroli, Georges Azuelos, G. Vasseur, Margret Fincke-Keeler, B. Lorazo, J. E. Pilcher, D. Karlen, C. Burgard, H. Przysiezniak, Andris Skuja, Christoph Schwick, F. Lamarche, P. G. Estabrooks, C. M. Hawkes, M. Cooper, Daniel Lellouch, S. A. Robins, M. Fierro, J. F. Kral, K. W. Bell, J. P. Martin, R. J. Hemingway, J. A. McKenna, M. Hauschild, Tetsuro Mashimo, Takehiko Mori, P. Pfister, P. E.L. Clarke, P. S. Wells, P. M. Watkins, H. G. Evans, S. Barnett, M. J. Oreglia, J. Steuerer, S. De Jong, Max Weber, P. Jovanovic, Austin Ball, M. J. Goodrick, D. Menszner, T. Hilse, Randall Sobie, I. Cohen, G. D. Lafferty, Terry Richard Wyatt, O. Runolfsson, W. Gorn, B. Fabbro, A. Yeaman, B. Panzer-Steindel, J. C. Hill, N. K. Watson, Misao Sasaki, Alessandro Montanari, J. R. Carter, T. W. Pritchard, G. N. Patrick, C. Beeston, M. Coupland, Claudio Grandi, D. Hochman, Sachio Komamiya, Gideon Alexander, Paolo Capiluppi, E. Ros, Gunter Wolf, F. C. Grant, M. A. Whalley, P. M. Hattersley, T. P. Kokott, A. Luig, R. Yaari, S. Bethke, Marco Cuffiani, A. Buijs, D. M. Strom, C. Stegmann, K. Stephens, Kiyotomo Kawagoe, P. F. Harrison, J. R. McNutt, P. D. Acton, Stephen Lloyd, M. Tecchio, Ehud Duchovni, S. Wotton, M. Jimack, P. Weber, H. Ihssen, S. W. Gensler, S. J. Hillier, T. Kobayashi, G. Duckeck, R. Ströhmer, C. J. Virtue, V. Gibson, G. Quast, John Baines, H. M. Bosch, Wolfram Dietrich Zeuner, D. R. Ward, G. Transtromer, A. Astbury, U. Müller, A. J. Martin, Paul Kyberd, F. K. Loebinger, A. Rollnik, R. Giacomelli, John Allison, R. G. Kellogg, D. S. Koetke, Stefano Marcellini, James Letts, J. Mildenberger, Harold Nguyen, Gordon H. Hanson, M. W. Redmond, C. K. Hargrove, Matthias Schröder, H. Lafoux, N. Paz-Jaoshvili, Tara Shears, M. J. Pearce, Horst Breuker, C. Markus, P. Paschievici, D. Pitman, M. H. Lehto, D. M. Gingrich, P. Berlich, L. Köpke, D. R. Rust, A. M. Lee, J. Banks, N. J. Tresilian, R. D. Heuer, Fabrizio Fabbri, D. Van den plas, D. E. Plane, P. Bentkowski, G. M. Dallavalle, Alan Watson, D. J.P. Dumas, W. R. Gibson, A. Beck, E. Heflin, R. M. Brown, Lorne Levinson, B. W. Kennedy, E. Torrente-Lujan, C. Sbarra, Michael Dittmar, G. Yekutieli, A. A. Carter, Roger Jones, R. Van Kooten, R. E. Hughes-Jones, J. von Krogh, Dave Robinson, L. A. del Pozo, T. J. McMahon, J. Schwiening, R. K. Carnegie, J. A. Wilson, W. Schappert, A. Skillman, M. A. Thomson, A. Gaidot, M. Kuwano, T. Wlodek, M. Sproston, P. Routenburg, N. Tesch, A. Dieckmann, P. A. Elcombe, J. Becker, G. J. VanDalen, J. M. Lorah, and W. Mohr
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Physics ,Nuclear and High Energy Physics ,Particle physics ,Magnetic moment ,Solar neutrino ,High Energy Physics::Phenomenology ,Supersymmetry ,Parameter space ,lcsh:QC1-999 ,Nuclear physics ,R-parity ,High Energy Physics::Experiment ,Neutrino ,Photino ,Particle Physics - Experiment ,lcsh:Physics ,Lepton - Abstract
A search for unstable, massive photinos pair produced in e + e − collisions has been performed using the OPAL detector at LEP. The data sample corresponds to an integrated luminosity of 21 pb −1 collected at center-of-mass energies near the Z 0 resonance. The unstable photino is assumed to decay into τ ± / gn l ( l = e or μ ) final states, thereby violating individual lepton numbers and R parity. This search is inspired by a particular model of supersymmetry which is of interest within the context of solar neutrino experiments because it allows for a large neutrino magnetic moment. The present search excludes a large portion of the parameter space allowed by the model.
- Published
- 1993
3. Measurement of the Q(2) evolution of the photon structure function F-2(gamma)
- Author
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K. Ackerstaff, G. Alexander, J. Allison, N. Altekamp, K.J. Anderson, S. Anderson, S. Arcelli, S. Asai, D. Axen, G. Azuelos, A.H. Ball, E. Barberio, T. Barillari, R.J. Barlow, R. Bartoldus, J.R. Batley, S. Baumann, J. Bechtluft, C. Beeston, T. Behnke, A.N. Bell, K.W. Bell, G. Bella, S. Bentvelsen, S. Bethke, O. Biebel, A. Biguzzi, S.D. Bird, V. Blobel, I.J. Bloodworth, J.E. Bloomer, M. Bobinski, P. Bock, D. Bonacorsi, M. Boutemeur, B.T. Bouwens, S. Braibant, L. Brigliadori, R.M. Brown, H.J. Burckhart, C. Burgard, R. Bürgin, P. Capiluppi, R.K. Carnegie, A.A. Carter, J.R. Carter, C.Y. Chang, D.G. Charlton, D. Chrisman, P.E.L. Clarke, I. Cohen, J.E. Conboy, O.C. Cooke, M. Cuffiani, S. Dado, C. Dallapiccola, G.M. Dallavalle, R. Davies, S. De Jong, L.A. del Pozo, K. Desch, B. Dienes, M.S. Dixit, E. do Couto e Silva, M. Doucet, E. Duchovni, G. Duckeck, I.P. Duerdoth, D. Eatough, J.E.G. Edwards, P.G. Estabrooks, H.G. Evans, M. Evans, F. Fabbri, M. Fanti, A.A. Faust, F. Fiedler, M. Fierro, H.M. Fischer, I. Fleck, R. Folman, D.G. Fong, M. Foucher, A. Fürtjes, D.I. Futyan, P. Gagnon, J.W. Gary, J. Gascon, S.M. Gascon-Shotkin, N.I. Geddes, C. Geich-Gimbel, T. Geralis, G. Giacomelli, P. Giacomelli, R. Giacomelli, V. Gibson, W.R. Gibson, D.M. Gingrich, D. Glenzinski, J. Goldberg, M.J. Goodrick, W. Gorn, C. Grandi, E. Gross, J. Grunhaus, M. Gruwé, C. Hajdu, G.G. Hanson, M. Hansroul, M. Hapke, C.K. Hargrove, P.A. Hart, C. Hartmann, M. Hauschild, C.M. Hawkes, R. Hawkings, R.J. Hemingway, M. Herndon, G. Herten, R.D. Heuer, M.D. Hildreth, J.C. Hill, S.J. Hillier, P.R. Hobson, R.J. Homer, A.K. Honma, D. Horváth, K.R. Hossain, R. Howard, P. Hüntemeyer, D.E. Hutchcroft, P. Igo-Kemenes, D.C. Imrie, M.R. Ingram, K. Ishii, A. Jawahery, P.W. Jeffreys, H. Jeremie, M. Jimack, A. Joly, C.R. Jones, G. Jones, M. Jones, U. Jost, P. Jovanovic, T.R. Junk, D. Karlen, V. Kartvelishvili, K. Kawagoe, T. Kawamoto, P.I. Kayal, R.K. Keeler, R.G. Kellogg, B.W. Kennedy, J. Kirk, A. Klier, S. Kluth, T. Kobayashi, M. Kobel, D.S. Koetke, T.P. Kokott, M. Kolrep, S. Komamiya, T. Kress, P. Krieger, J. von Krogh, P. Kyberd, G.D. Lafferty, R. Lahmann, W.P. Lai, D. Lanske, J. Lauber, S.R. Lautenschlager, J.G. Layter, D. Lazic, A.M. Lee, E. Lefebvre, D. Lellouch, J. Letts, L. Levinson, S.L. Lloyd, F.K. Loebinger, G.D. Long, M.J. Losty, J. Ludwig, A. Macchiolo, A. Macpherson, M. Mannelli, S. Marcellini, C. Markus, A.J. Martin, J.P. Martin, G. Martinez, T. Mashimo, P. Mättig, W.J. McDonald, J. McKenna, E.A. Mckigney, T.J. McMahon, R.A. McPherson, F. Meijers, S. Menke, F.S. Merritt, H. Mes, J. Meyer, A. Michelini, G. Mikenberg, D.J. Miller, A. Mincer, R. Mir, W. Mohr, A. Montanari, T. Mori, M. Morii, U. Müller, S. Mihara, K. Nagai, I. Nakamura, H.A. Neal, B. Nellen, R. Nisius, S.W. O'Neale, F.G. Oakham, F. Odorici, H.O. Ogren, A. Oh, N.J. Oldershaw, M.J. Oreglia, S. Orito, J. Pálinkás, G. Pásztor, J.R. Pater, G.N. Patrick, J. Patt, M.J. Pearce, R. Perez-Ochoa, S. Petzold, P. Pfeifenschneider, J.E. Pilcher, J. Pinfold, D.E. Plane, P. Poffenberger, B. Poli, A. Posthaus, D.L. Rees, D. Rigby, S. Robertson, S.A. Robins, N. Rodning, J.M. Roney, A. Rooke, E. Ros, A.M. Rossi, P. Routenburg, Y. Rozen, K. Runge, O. Runolfsson, U. Ruppel, D.R. Rust, R. Rylko, K. Sachs, T. Saeki, E.K.G. Sarkisyan, C. Sbarra, A.D. Schaile, O. Schaile, F. Scharf, P. Scharff-Hansen, P. Schenk, J. Schieck, P. Schleper, B. Schmitt, S. Schmitt, A. Schöning, M. Schröder, H.C. Schultz-Coulon, M. Schumacher, C. Schwick, W.G. Scott, T.G. Shears, B.C. Shen, C.H. Shepherd-Themistocleous, P. Sherwood, G.P. Siroli, A. Sittler, A. Skillman, A. Skuja, A.M. Smith, G.A. Snow, R. Sobie, S. Söldner-Rembold, R.W. Springer, M. Sproston, K. Stephens, J. Steuerer, B. Stockhausen, K. Stoll, D. Strom, P. Szymanski, R. Tafirout, S.D. Talbot, S. Tanaka, P. Taras, S. Tarem, R. Teuscher, M. Thiergen, M.A. Thomson, E. von Törne, S. Towers, I. Trigger, Z. Trócsányi, E. Tsur, A.S. Turcot, M.F. Turner-Watson, P. Utzat, R. Van Kooten, M. Verzocchi, P. Vikas, E.H. Vokurka, H. Voss, F. Wäckerle, A. Wagner, C.P. Ward, D.R. Ward, P.M. Watkins, A.T. Watson, N.K. Watson, P.S. Wells, N. Wermes, J.S. White, B. Wilkens, G.W. Wilson, J.A. Wilson, G. Wolf, T.R. Wyatt, S. Yamashita, G. Yekutieli, V. Zacek, and D. Zer-Zion
- Subjects
Physics ,Nuclear and High Energy Physics ,Particle physics ,Range (particle radiation) ,010308 nuclear & particles physics ,2-Photon Production Processes ,Microvertex Detector ,FOS: Physical sciences ,LEP ,Generator ,01 natural sciences ,Photon structure function ,Luminosity ,High Energy Physics - Experiment ,Q2 ,Scattering ,GEV2 ,High Energy Physics - Experiment (hep-ex) ,High-Energy ,0103 physical sciences ,Leading Order ,010306 general physics ,Opal Detector ,Particle Physics - Experiment - Abstract
New measurements are presented of the photon structure function F_2^gamma(Q) at four values of Q^2 between 9 and 59 GeV/c^2 based on data collected with the OPAL detector at centre-of-mass energies of 161-172 GeV, with a total integrated luminosity of 18.1 pb^-1. The evolution of F_2^gamma with Q^2 in bins of x is determined in the Q^2 range from 1.86 to 135 GeV/c^2 using data taken at centre-of-mass energies of 91 GeV and 161-172 GeV. F_2^gamma is observed to increase with Q^2 with a slope of 1/alpha_em dF_2^gamma/dln(Q^2) = 0.10 +0.05 -0.03 measured in the range 0.1 < x < 0.6., 22 pages, LaTeX, 4 eps figures included, accepted by Phys. Lett. B
- Published
- 1998
4. Search for charged Higgs bosons in e(+)e(-) collisions at root s = 130-172 GeV
- Author
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Silvia Arcelli, H. O. Ogren, Christoph Geich-Gimbel, J. Lauber, R. W. Springer, S. Baumann, E. A. Mckigney, Vakhtang Kartvelishvili, S. M. Gascon-Shotkin, K. Stoll, Andris Skuja, R. Davis, W. P. Lai, S. D. Talbot, S. Petzold, J. E. Conboy, A. Fürtjes, A. D. Schaile, W. R. Gibson, Gabriella Pasztor, P. Vannerem, D. Eatough, M. Schumacher, E. Lefebvre, E. Tsur, Tetsuro Mashimo, Lutz Feld, J. M. Roney, D. Lui, D. I. Futyan, F. Odorici, Matthew Evans, A. M. Rossi, G. A. Snow, C. P. Ward, M. Verzocchi, K. W. Bell, J. Pálinkás, C. Y. Chang, P. Taras, H. A. Neal, S. Söldner-Rembold, Michael Kobel, W. Gorn, S. Yamashita, J. C. Hill, P. Igo-Kemenes, K. Ishii, H. Jeremie, Richard Teuscher, O. Schaile, J. Grunhaus, Erez Etzion, S. Betts, M. Hapke, H. M. Fischer, Sven Menke, Dave Charlton, Stefan Kluth, M. A. Thomson, A. S. Turcot, E. K. U. Gross, Ehud Duchovni, Allen Mincer, F. Fiedler, Julie Kirk, P. G. Estabrooks, W. J. McDonald, B. C. Shen, Claire Shepherd-Themistocleous, R. K. Keeler, Shlomit Tarem, D. E. Hutchcroft, A. J. Martin, M. Boutemeur, F. S. Merritt, R. Bürgin, S. D. Bird, M. Jimack, M. Sproston, J. Letts, R. J. Hemingway, N. K. Watson, A. Michelini, Siegfried Bethke, B. W. Kennedy, L. Brigliadori, Sachio Komamiya, A. K. Honma, R. M. Brown, Lorne Levinson, M. J. Oreglia, P. Jovanovic, W. G. Scott, K. Sachs, Austin Ball, Theodoros Geralis, Daniel Lellouch, A. T. Watson, P. M. Watkins, I. Nakamura, D. Axen, A. Jawahery, Peter Krieger, Shlomo Dado, A. A. Faust, James Pinfold, R. Perez-Ochoa, Gideon Bella, M. Kolrep, H. J. Burckhart, S. A. Robins, T. Kobayashi, Takehiko Mori, D. G. Fong, H. Mes, I. P. Duerdoth, T. P. Kokott, J. Gascon, Alessandro Montanari, P. Mättig, S. Braibant, Jacqueline Batley, J. Bechtluft, T. Saeki, Peter Sherwood, K. Ackerstaff, U. Jost, R. Mir, R. Hawkings, C. K. Hargrove, V. Zacek, W. M. Sang, Alessandra Fanfani, Alexander Wagner, J. A. McKenna, A. Skillman, S. W. O'Neale, G. Azuelos, Tara Shears, Randall Sobie, G. D. Lafferty, Satoshi Mihara, T. Behnke, Giora Mikenberg, S. F. Ashby, K. J. Anderson, J. R. Carter, G. N. Patrick, J. W. Gary, N. I. Geddes, Michael Hildreth, D. Glenzinski, Dezso Horvath, D. S. Koetke, R. Kowalewski, M. J. Losty, J. Schieck, W. Mohr, Raimund Ströhmer, P. Hüntemeyer, Marcello Mannelli, C. R. Jones, J. Ludwig, P. A. Hart, K. Runge, P. Bock, Guenter Duckeck, N. L. Rodning, Jean-Arcady Meyer, F. G. Oakham, B. Schmitt, E. L. Barberio, A. Posthaus, B. Poli, P. Poffenberger, Otmar Biebel, P. Scharff-Hansen, I. J. Bloodworth, A. Macchiolo, A. Joly, C. Dallapiccola, J. Goldberg, Gideon Alexander, Paolo Capiluppi, C. M. Hawkes, S. B. Anderson, R. L. Coxe, P. Szymanski, B. Nellen, M. F. Turner-Watson, Peter R Hobson, N. Altekamp, H. Voss, A. M. Smith, P. Gagnon, R. J. Barlow, Beatrix Dienes, C. Sbarra, D. J. Miller, Yoram Rozen, F. Scharf, A. Hocker, Richard Nisius, K. Stephens, P. I. Kayal, D. Zer-Zion, Stan Bentvelsen, P. Routenburg, German Martinez, D. Chrisman, G. D. Long, B. List, M. Foucher, John Allison, Marco Cuffiani, Volker Blobel, H. G. Evans, M. Fierro, M. J. Goodrick, I. Cohen, A. Sittler, Peter Schleper, Junichi Kanzaki, D. Karlen, V. Gibson, Reda Tafirout, Klaus Kurt Desch, Zoltan Laszlo Trocsanyi, G. Yekutieli, Norbert Wermes, Sherry Towers, T. Kawamoto, Christoph Rembser, E. Torrence, Stefan Schmitt, S. Orito, R. G. Kellogg, Csaba Hajdu, P. E.L. Clarke, T. R. Junk, M. K. Jones, Stefano Marcellini, Stephen Lloyd, Shoji Asai, Ekg Sarkisyan, B. Stockhausen, Paul Kyberd, P. W. Jeffreys, J. P. Martin, F. K. Loebinger, I. Trigger, Matthias Schröder, J. Steuerer, Ivor Fleck, Joleen Pater, A. Klier, R. Giacomelli, D. R. Ward, A. Oh, T. Kress, S. De Jong, C. Hartmann, D. E. Plane, Stephen Hillier, U. Ruppel, G. M. Dallavalle, M. Thiergen, D. M. Gingrich, A. A. Carter, Ron Folman, Paolo Giacomelli, M. Hansroul, P. Vikas, D. Lanske, P. Utzat, S. R. Lautenschlager, A. Biguzzi, A. Rooke, C. Burgard, R. J. Homer, O. Runolfsson, J. G. Layter, Claudio Grandi, T. J. McMahon, O. C. Cooke, P. Pfeifenschneider, C. Couyoumtzelis, J. Patt, André Schöning, O. Sahr, R. K. Carnegie, M. Herndon, M. Bobinski, J. A. Wilson, R. Lahmann, D. C. Imrie, D. Lazic, Daniele Bonacorsi, G. P. Siroli, Christoph Schwick, J. von Krogh, G. G. Hanson, M. Gruwé, L. A. del Pozo, G. Giacomelli, I. Lawson, Kiyotomo Kawagoe, A. De Roeck, M. S. Dixit, Frans Meijers, K. R. Hossain, K. Nagai, D. R. Rust, A. M. Lee, E. von Törne, R. Van Kooten, F. Wäckerle, M. Fanti, Robert McPherson, Mathieu Doucet, R. D. Heuer, Fabrizio Fabbri, A. Macpherson, R. Howard, J. S. White, Ikuo Ueda, D. M. Strom, P. S. Wells, Terry Richard Wyatt, N. J. Oldershaw, S. Robertson, Gregor Herten, J. E. Pilcher, G. W. Wilson, M. Hauschild, C. Markopoulos, C. Markus, E. H. Vokurka, and R. Bartoldus
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Nuclear and High Energy Physics ,Particle physics ,Electron–positron annihilation ,Microvertex Detector ,FOS: Physical sciences ,01 natural sciences ,7. Clean energy ,High-Energies ,Lower limit ,High Energy Physics - Experiment ,Nuclear physics ,High Energy Physics - Experiment (hep-ex) ,0103 physical sciences ,010306 general physics ,Boson ,Physics ,Luminosity (scattering theory) ,010308 nuclear & particles physics ,Branching fraction ,High Energy Physics::Phenomenology ,Monte-Carlo Program ,LEP ,Higgs boson ,Couplings ,High Energy Physics::Experiment ,Decays ,Cross-Sections ,Particle Physics - Experiment - Abstract
A search is described to detect charged Higgs bosons via the process e^+e^- -> H^+H^-, using data collected by the OPAL detector at center-of-mass energies of 130-172 GeV with a total integrated luminosity of 25 pb^-1. The decay channels are assumed to be H^+ -> qq'(bar) and H^+ -> \tau^+ \nu_{\tau}. No evidence for charged Higgs boson production is observed. The lower limit for its mass is determined to be 52 GeV at 95% confidence level, independent of the H^+ -> \tau^+ \nu_{\tau} branching ratio., Comment: 19 pages, LaTeX, uses a4p.sty, 3 eps figures included, submitted to Phys. Lett. B
- Published
- 1998
5. The LEAP checklist for Laboratory Evaluation and Analytical Performance characteristics reporting of clinical measurement procedures.
- Author
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Loh TP, Cooke BR, Tran TCM, Markus C, Zakaria R, Ho CS, Theodorsson E, and Greaves RF
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- Humans, Reference Standards, Laboratories, Checklist, Clinical Laboratory Services
- Abstract
Reporting a measurement procedure and its analytical performance following method evaluation in a peer-reviewed journal is an important means for clinical laboratory practitioners to share their findings. It also represents an important source of evidence base to help others make informed decisions about their practice. At present, there are significant variations in the information reported in laboratory medicine journal publications describing the analytical performance of measurement procedures. These variations also challenge authors, readers, reviewers, and editors in deciding the quality of a submitted manuscript. The International Federation of Clinical Chemistry and Laboratory Medicine Working Group on Method Evaluation Protocols (IFCC WG-MEP) developed a checklist and recommends its adoption to enable a consistent approach to reporting method evaluation and analytical performance characteristics of measurement procedures in laboratory medicine journals. It is envisioned that the LEAP checklist will improve the standardisation of journal publications describing method evaluation and analytical performance characteristics, improving the quality of the evidence base that is relied upon by practitioners., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)
- Published
- 2023
- Full Text
- View/download PDF
6. Calibration frequency and analytical variability of laboratory measurements.
- Author
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Lim CY, Ow Yang S, Markus C, and Loh TP
- Subjects
- Humans, Least-Squares Analysis, Computer Simulation, Quality Control, Uncertainty, Calibration
- Abstract
Background: There is uncertainty whether increased frequency of calibrations may affect the overall analytical variability of a measurement procedure as reflected in quality control (QC) performance. In this simulation study, we examined the impact of calibration frequencies on the variability of laboratory measurements., Methods: A 5-point calibration curve was modeled with simulated concentrations ranging from 10 to 10,000 mmol/l, and signal intensities with CVs of 3 % around the mean, under a Gaussian distribution. 3 levels of QC (20, 150, 600 mmol/l) interspersed within the analytical measurement range were also simulated., Results: The CV of the 3 QC levels remained stable across the different calibration frequencies simulated (5, 10, 15 and 30 QC measurements per recalibration episode). The imprecision was greatest (18 %) at the lowest concentration of 20 mmol/l, when the calibration curve was derived using ordinary least squares regression, reducing to 3.5 % and 3.8 % at 150 and 600 mmol/l, respectively. The CV of all 3 QC concentrations remained constant at 3.4 % and close the predefined CV (3 %) when weighted least squares regression was used to derive the calibration model. Similar findings were observed with 2-point calibrations using WLS models at narrower concentration ranges (50 and 100 mmol/l as well as 50 and 500 mmol/l)., Discussion: Within the parameters of the simulation study, an increased frequency of calibration events does not adversely impact the overall analytical performance of a measurement procedure under most circumstances., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)
- Published
- 2023
- Full Text
- View/download PDF
7. Lot-to-lot reagent verification: Effect of sample size and replicate measurement on linear regression approaches.
- Author
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Koh NWX, Markus C, Loh TP, and Lim CY
- Subjects
- Humans, Indicators and Reagents, Least-Squares Analysis, Linear Models, Sample Size, Laboratories
- Abstract
Background: We investigate the simulated impact of varying sample size and replicate number using ordinary least squares (OLS) and Deming regression (DR) in both weighted and unweighted forms, when applied to paired measurements in lot-to-lot verification., Methods: Simulation parameter investigated in this study were: range ratio, analytical coefficient of variation, sample size, replicates, alpha (level of significance) and constant and proportional biases. For each simulation scenario, 10,000 iterations were performed, and the average probability of bias detection was determined., Results: Generally, the weighted forms of regression significantly outperformed the unweighted forms for bias detection. At the low range ratio (1:10), for both weighted OLS and DR, improved bias detection was observed with greater number of replicates, than increasing the number of comparison samples. At the high range ratio (1:1000), for both weighted OLS and DR, increasing the number of replicates above two is only slightly more advantageous in the scenarios examined. Increasing the numbers of comparison samples resulted in better detection of smaller biases between reagent lots., Conclusions: The results of this study allow laboratories to determine a tailored approach to lot-to-lot verification studies, balancing the number of replicates and comparison samples with the analytical performance of measurement procedures involved., (Copyright © 2022 Elsevier B.V. All rights reserved.)
- Published
- 2022
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