Search

Your search keyword '"G. Bohm"' showing total 29 results
Start Over Author "G. Bohm" Search Limiters Peer Reviewed
29 results on '"G. Bohm"'

1. Rare germline heterozygous missense variants in BRCA1-associated protein 1, BAP1, cause a syndromic neurodevelopmental disorder

Author

Sébastien Küry, Frédéric Ebstein, Alice Mollé, Thomas Besnard, Ming-Kang Lee, Virginie Vignard, Tiphaine Hery, Mathilde Nizon, Grazia M.S. Mancini, Jacques C. Giltay, Benjamin Cogné, Kirsty McWalter, Wallid Deb, Hagar Mor-Shaked, Hong Li, Rhonda E. Schnur, Ingrid M. Wentzensen, Anne-Sophie Denommé-Pichon, Cynthia Fourgeux, Frans W. Verheijen, Eva Faurie, Rachel Schot, Cathy A. Stevens, Daphne J. Smits, Eileen Barr, Ruth Sheffer, Jonathan A. Bernstein, Chandler L. Stimach, Eliana Kovitch, Vandana Shashi, Kelly Schoch, Whitney Smith, Richard H. van Jaarsveld, Anna C.E. Hurst, Kirstin Smith, Evan H. Baugh, Suzanne G. Bohm, Emílie Vyhnálková, Lukáš Ryba, Capucine Delnatte, Juanita Neira, Dominique Bonneau, Annick Toutain, Jill A. Rosenfeld, Séverine Audebert-Bellanger, Brigitte Gilbert-Dussardier, Sylvie Odent, Frédéric Laumonnier, Seth I. Berger, Ann C.M. Smith, Franck Bourdeaut, Marc-Henri Stern, Richard Redon, Elke Krüger, Raphaël Margueron, Stéphane Bézieau, Jeremie Poschmann, Bertrand Isidor, Centre hospitalier universitaire de Nantes (CHU Nantes), unité de recherche de l'institut du thorax UMR1087 UMR6291 (ITX), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Nantes Université - UFR de Médecine et des Techniques Médicales (Nantes Univ - UFR MEDECINE), Nantes Université - pôle Santé, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Santé, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ), Universität Greifswald - University of Greifswald, Centre de Recherche en Transplantation et Immunologie - Center for Research in Transplantation and Translational Immunology (U1064 Inserm - CR2TI), Institut National de la Santé et de la Recherche Médicale (INSERM)-Nantes Université - UFR de Médecine et des Techniques Médicales (Nantes Univ - UFR MEDECINE), Génétique et Biologie du Développement, Institut Curie [Paris]-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Erasmus University Medical Center [Rotterdam] (Erasmus MC), University Medical Center [Utrecht], GeneDx [Gaithersburg, MD, USA], Hadassah Hebrew University Medical Center [Jerusalem], Emory University School of Medicine, Emory University [Atlanta, GA], Laboratoire de Biologie Neurovasculaire Intégrée [Angers] (CNRS UMR6214 - INSERM U771), Université d'Angers (UA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Faculté de Médecine d'Angers, MitoVasc - Physiopathologie Cardiovasculaire et Mitochondriale (MITOVASC), Université d'Angers (UA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), University of Tennessee System, Stanford University, Duke University Medical Center, University of Alabama at Birmingham [ Birmingham] (UAB), Columbia University [New York], Charles University [Prague] (CU), Centre Hospitalier Universitaire d'Angers (CHU Angers), PRES Université Nantes Angers Le Mans (UNAM), Imagerie et cerveau (iBrain - Inserm U1253 - UNIV Tours ), Université de Tours (UT)-Institut National de la Santé et de la Recherche Médicale (INSERM), Baylor College of Medicine (BCM), Baylor University, Centre Hospitalier Régional Universitaire de Brest (CHRU Brest), Unité neurovasculaire et troubles cognitifs (Neuvacod), Université de Poitiers, CHU Pontchaillou [Rennes], Institut de Génétique et Développement de Rennes (IGDR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)-Structure Fédérative de Recherche en Biologie et Santé de Rennes ( Biosit : Biologie - Santé - Innovation Technologique ), Centre de référence Maladies Rares CLAD-Ouest [Rennes], Children's National Medical Center, National Human Genome Research Institute (NHGRI), Institut Curie [Paris], Unité de génétique et biologie des cancers (U830), Institut Curie [Paris]-Institut National de la Santé et de la Recherche Médicale (INSERM), Greifswald University Hospital, Research reported in this manuscript was supported by the NIH Common Fund through the Office of Strategic Coordination/Office of the NIH Director under award number U01HG007672 to V.S. Further support was obtained by funding from the German Research Foundation (SFBTR 167 A4, GRK2719 B4) to E.K, and Clinical Genetics

Subjects
Male, Heterozygote, Proteasome Endopeptidase Complex, tumor, Adolescent, T-Lymphocytes, Ubiquitin-Protein Ligases, [SDV]Life Sciences [q-bio], Mutation, Missense, UPS, ubiquitin-proteasome system, chromatin remodeling, Histones, SDG 3 - Good Health and Well-being, Loss of Function Mutation, Report, ubiquitin, Genetics, Humans, cancer, Family, BAP1, Child, deubiquitination, Germ-Line Mutation, Genetics (clinical), [SDV.GEN]Life Sciences [q-bio]/Genetics, neurodevelopment, BRCA1 Protein, Tumor Suppressor Proteins, Ubiquitination, Infant, Chromatin Assembly and Disassembly, BRCA1, Chromatin, Gene Expression Regulation, Neurodevelopmental Disorders, intellectual disability, Child, Preschool, histone 2A, Female, Host Cell Factor C1, Ubiquitin Thiolesterase
Abstract

International audience; Nuclear deubiquitinase BAP1 (BRCA1-associated protein 1) is a core component of multiprotein complexes that promote transcription by reversing the ubiquitination of histone 2A (H2A). BAP1 is a tumor suppressor whose germline loss-of-function variants predispose to cancer. To our knowledge, there are very rare examples of different germline variants in the same gene causing either a neurodevelopmental disorder (NDD) or a tumor predisposition syndrome. Here, we report a series of 11 de novo germline heterozygous missense BAP1 variants associated with a rare syndromic NDD. Functional analysis showed that most of the variants cannot rescue the consequences of BAP1 inactivation, suggesting a loss-of-function mechanism. In T cells isolated from two affected children, H2A deubiquitination was impaired. In matching peripheral blood mononuclear cells, histone H3 K27 acetylation ChIP-seq indicated that these BAP1 variants induced genome-wide chromatin state alterations, with enrichment for regulatory regions surrounding genes of the ubiquitin-proteasome system (UPS). Altogether, these results define a clinical syndrome caused by rare germline missense BAP1 variants that alter chromatin remodeling through abnormal histone ubiquitination and lead to transcriptional dysregulation of developmental genes.

Published
2022
Full Text
View/download PDF

2. Rare HCV subtypes and retreatment outcomes in a cohort of European DAA-experienced patients

Author

Julia Dietz, Christiana Graf, Christoph P. Berg, Kerstin Port, Katja Deterding, Peter Buggisch, Kai-Henrik Peiffer, Johannes Vermehren, Georg Dultz, Andreas Geier, Florian P. Reiter, Tony Bruns, Jörn M. Schattenberg, Elena Durmashkina, Thierry Gustot, Christophe Moreno, Janina Trauth, Thomas Discher, Janett Fischer, Thomas Berg, Andreas E. Kremer, Beat Müllhaupt, Stefan Zeuzem, Christoph Sarrazin, C. Antoni, A. Teufel, R. Vogelmann, M. Ebert, J. Balavoine, E. Giostra, M. Berning, J. Hampe, T. Boettler, C. Neumann-Haefelin, R. Thimme, A. De Gottardi, A. Rauch, N. Semmo, V. Ellenrieder, M. Gress, A. Herrmann, A. Stallmach, D. Hoffmann, U. Protzer, A. Kodal, M. Löbermann, T. Götze, V. Keitel-Anselmino, C.M. Lange, R. Zachoval, J. Mayerle, A. Maieron, P. Michl, U. Merle, D. Moradpour, J.-P. Chave, M. Muche, H.-J. Epple, M. Müller-Schilling, F. Kocheise, T. Müller, F. Tacke, E. Roeb, J. Rissland, M. Krawczyk, P. Schulze, D. Semela, U. Spengler, J. Rockstroh, C.P. Strassburg, J. Siebler, J. Schulze zur Wiesch, F. Piecha, J. von Felden, S. Jordan, A. Lohse, M. Sprinzl, P. Galle, R. Stauber, B. Strey, W. Steckstor, W. Schmiegel, N.H. Brockmeyer, A. Canbay, C. Trautwein, F. Uschner, J. Trebicka, T. Weber, H. Wedemeyer, M. Cornberg, M. Manns, P. Wietzke-Braun, R. Günther, K. Willuweit, G. Hilgard, H. Schmidt, E. Zizer, J. Backhus, T. Seufferlein, O. Al-Taie, W. Angeli, S. Beckebaum, A. Erhardt, A. Garrido-Lüneburg, H. Gattringer, D. Genné, M. Gschwantler, F. Gundling, S. Hametner, R. Schöfl, S. Haag, H. Heinzow, T. Heyer, C. Hirschi, A. Jussios, S. Kanzler, N. Kordecki, M. Kraus, U. Kullig, S. Wollschläger, L. Magenta, B. Terziroli Beretta-Piccoli, M. Menges, L. Mohr, K. Muehlenberg, C. Niederau, B. Paulweber, A. Petrides, M. Pinkernell, R. Piso, W. Rambach, L. Reinhardt, M. Reiser, B. Riecken, A. Rieke, J. Roth, M. Schelling, P. Schlee, A. Schneider, D. Scholz, E. Schott, M. Schuchmann, U. Schulten-Baumer, A. Seelhoff, A. Stich, F. Stickel, J. Ungemach, E. Walter, A. Weber, H. Wege, T. Winzer, W. Abels, M. Adler, F. Audebert, C. Baermann, E. Bästlein, R. Barth, K. Barthel, W. Becker, J. Behrends, J. Benninger, F. Berger, D. Berzow, T. Beyer, M. Bierbaum, O. Blaukat, A. Bodtländer, G. Böhm, N. Börner, U. Bohr, B. Bokemeyer, H.R. Bruch, D. Bucholz, P. Buggisch, K. Matschenz, J. Petersen, O. Burkhard, N. Busch, C. Chirca, R. Delker, J. Diedrich, M. Frank, M. Diehl, A.O. Tal, M. Schneider, A. Dienethal, P. Dietel, N. Dikopoulos, M. Dreck, F. Dreher, L. Drude, K. Ende, U. Ehrle, K. Baumgartl, F. Emke, R. Glosemeyer, G. Felten, D. Hüppe, J. Fischer, U. Fischer, D. Frederking, B. Frick, G. Friese, B. Gantke, P. Geyer, H.R. Schwind, M. Glas, T. Glaunsinger, F. Goebel, U. Göbel, B. Görlitz, R. Graf, H. Gruber, C. Hartmann, C. Klag, G. Härter, M. Herder, T. Heuchel, S. Heuer, H. Hinrichsen, B. Seegers, K.-H. Höffl, H. Hörster, J.-U. Sonne, W.P. Hofmann, F. Holst, M. Hunstiger, A. Hurst, E. Jägel-Guedes, C. John, M. Jung, B. Kallinowski, B. Kapzan, W. Kerzel, P. Khaykin, M. Klarhof, U. Klüppelberg, Wolfratshausen, K. Klugewitz, B. Knapp, U. Knevels, T. Kochsiek, A. Körfer, A. Köster, M. Kuhn, A. Langekamp, B. Künzig, R. Link, M. Littman, H. Löhr, T. Lutz, P. Gute, G. Knecht, U. Lutz, D. Mainz, I. Mahle, P. Maurer, S. Mauss, C. Mayer, H. Möller, R. Heyne, D. Moritzen, M. Mroß, M. Mundlos, U. Naumann, O. Nehls, K, R. Ningel, A. Oelmann, H. Olejnik, K. Gadow, E. Pascher, A. Philipp, M. Pichler, F. Polzien, R. Raddant, M. Riedel, S. Rietzler, M. Rössle, W. Rufle, A. Rump, C. Schewe, C. Hoffmann, D. Schleehauf, W. Schmidt, G. Schmidt-Heinevetter, J. Schmidtler-von Fabris, L. Schneider, A. Schober, S. Niehaus-Hahn, J. Schwenzer, T. Seidel, G. Seitel, C. Sick, K. Simon, D. Stähler, F. Stenschke, H. Steffens, K. Stein, M. Steinmüller, T. Sternfeld, K. Svensson, W. Tacke, G. Teuber, K. Teubner, J. Thieringer, A. Tomesch, U. Trappe, J. Ullrich, G. Urban, S. Usadel, A. von Lucadou, F. Weinberger, M. Werheid-Dobers, P. Werner, T. Winter, E. Zehnter, and A. Zipf

Subjects
Direct-acting antivirals, Hepatitis C Virus, rare HCV genotypes, resistance-associated substitutions, treatment response, Diseases of the digestive system. Gastroenterology, RC799-869
Abstract

Background and Aims: Data on the prevalence and characteristics of so-called rare HCV genotypes (GTs) in larger cohorts is limited. This study investigates the frequency of rare GT and resistance-associated substitutions and the efficacy of retreatment in a European cohort. Methods: A total of 129 patients with rare GT1-6 were included from the European resistance database. NS3, NS5A, and NS5B were sequenced and clinical parameters and retreatment efficacies were collected retrospectively. Results: Overall 1.5% (69/4,656) of direct-acting antiviral (DAA)-naive and 4.4% (60/1,376) of DAA-failure patients were infected with rare GT. Although rare GTs were almost equally distributed throughout GT1-6 in DAA-naive patients, we detected mainly rare GT4 (47%, 28/60 GT4; of these n = 17, subtype 4r) and GT3 (25%, 15/60 GT3, of these n = 8, subtype 3b) among DAA-failures. A total of 62% (37/60) of DAA failures had not responded to first-generation regimes and the majority was infected with rare GT4 (57%, 21/37). In contrast, among patients with failure to pangenotypic DAA regimens (38%, 23/60), infections with rare GT3 were overrepresented (57%, 13/23). Although NS5A RASs were uncommon in rare GT2, GT5a, and GT6, we observed combined RASs in rare GT1, GT3, and GT4 at positions 28, 30, 31, which can be considered as inherent. DAA failures with completed follow-up of retreatment, achieved a high SVR rate (94%, 45/48 modified intention-to-treat analysis; 92%, 45/49 intention-to-treat). Three patients with GT4f, 4r, or 3b, respectively, had virological treatment failure. Conclusions: In this European cohort, rare HCV GT were uncommon. Accumulation of specific rare GT in DAA-failure patients suggests reduced antiviral activities of DAA regimens. The limited global availability of pangenotypic regimens for first line therapy as well as multiple targeted regimens for retreatment could result in HCV elimination targets being delayed. Impact and implications: Data on the prevalence and characteristics of rare HCV genotypes (GT) in larger cohorts are still scarce. This study found low rates of rare HCV GTs among European HCV-infected patients. In direct-acting antiviral (DAA)-failure patients, rare GT3 subtypes accumulated after pangenotypic DAA treatment and rare GT4 after first generation DAA failure and viral resistance was detected at NS5A positions 28, 30, and 31. The limited global availability of pangenotypic DAA regimens for first line therapy as well as multiple targeted regimens for retreatment could result in HCV elimination targets being delayed.

Published
2024
Full Text
View/download PDF

3. Statistics of weighted Poisson events and its applications

Author

G. Bohm and G. Zech

Subjects
FOS: Computer and information sciences, Physics, Nuclear and High Energy Physics, Poisson binomial distribution, FOS: Physical sciences, Probability and statistics, Poisson distribution, Methodology (stat.ME), symbols.namesake, Compound Poisson distribution, Physics - Data Analysis, Statistics and Probability, Compound Poisson process, Statistics, symbols, Zero-inflated model, ddc:530, Poisson regression, Fractional Poisson process, Instrumentation, Statistics - Methodology, Data Analysis, Statistics and Probability (physics.data-an)
Abstract

The statistics of the sum of random weights where the number of weights is Poisson distributed has important applications in nuclear physics, particle physics and astrophysics. Events are frequently weighted according to their acceptance or relevance to a certain type of reaction. The sum is described by the compound Poisson distribution (CPD) which is shortly reviewed. It is shown that the CPD can be approximated by a scaled Poisson distribution (SPD). The SPD is applied to parameter estimation in situations where the data are distorted by resolution effects. It performs considerably better than the normal approximation that is usually used. A special Poisson bootstrap technique is presented which permits to derive confidence limits for observations following the CPD., Comment: 14 pages, 2 figures

Published
2014
Full Text
View/download PDF

4. K*0 and φ meson production in proton–nucleus interactions at $\sqrt{s}=41.6\text{GeV}$

Author

I. Abt, M. Adams, M. Agari, H. Albrecht, A. Aleksandrov, V. Amaral, A. Amorim, S.J. Aplin, V. Aushev, Y. Bagaturia, V. Balagura, M. Bargiotti, O. Barsukova, J. Bastos, J. Batista, C. Bauer, T.S. Bauer, A. Belkov, I. Belotelov, A. Bertin, B. Bobchenko, M. Böcker, A. Bogatyrev, G. Bohm, M. Bräuer, M. Bruinsma, M. Bruschi, P. Buchholz, T. Buran, J. Carvalho, P. Conde, C. Cruse, M. Dam, K.M. Danielsen, M. Danilov, S. De Castro, H. Deppe, X. Dong, H.B. Dreis, V. Egorytchev, K. Ehret, F. Eisele, D. Emeliyanov, S. Essenov, L. Fabbri, P. Faccioli, M. Feuerstack-Raible, J. Flammer, B. Fominykh, M. Funcke, L. Garrido, A. Gellrich, B. Giacobbe, J. Gläß, D. Goloubkov, Y. Golubkov, A. Golutvin, I. Golutvin, I. Gorbounov, A. Gorišek, O. Gouchtchine, D.C. Goulart, S. Gradl, W. Gradl, F. Grimaldi, J. Groth-Jensen, Y. Guilitsky, J.D. Hansen, J.M. Hernández, W. Hofmann, M. Hohlmann, T. Hott, W. Hulsbergen, U. Husemann, O. Igonkina, M. Ispiryan, T. Jagla, C. Jiang, H. Kapitza, S. Karabekyan, N. Karpenko, S. Keller, J. Kessler, F. Khasanov, Y. Kiryushin, I. Kisel, E. Klinkby, K.T. Knöpfle, H. Kolanoski, S. Korpar, C. Krauss, P. Kreuzer, P. Križan, D. Krücker, S. Kupper, T. Kvaratskheliia, A. Lanyov, K. Lau, B. Lewendel, T. Lohse, B. Lomonosov, R. Männer, R. Mankel, S. Masciocchi, I. Massa, I. Matchikhilian, G. Medin, M. Medinnis, M. Mevius, A. Michetti, Y. Mikhailov, R. Mizuk, R. Muresan, M. zur Nedden, M. Negodaev, M. Nörenberg, S. Nowak, M.T. Núñez Pardo de Vera, M. Ouchrif, F. Ould-Saada, C. Padilla, D. Peralta, R. Pernack, R. Pestotnik, B.A. Petersen, M. Piccinini, M.A. Pleier, M. Poli, V. Popov, D. Pose, S. Prystupa, V. Pugatch, Y. Pylypchenko, J. Pyrlik, K. Reeves, D. Reßing, H. Rick, I. Riu, P. Robmann, I. Rostovtseva, V. Rybnikov, F. Sánchez, A. Sbrizzi, M. Schmelling, B. Schmidt, A. Schreiner, H. Schröder, U. Schwanke, A.J. Schwartz, A.S. Schwarz, B. Schwenninger, B. Schwingenheuer, F. Sciacca, N. Semprini-Cesari, S. Shuvalov, L. Silva, L. Sözüer, S. Solunin, A. Somov, S. Somov, J. Spengler, R. Spighi, A. Spiridonov, A. Stanovnik, M. Starič, C. Stegmann, H.S. Subramania, M. Symalla, I. Tikhomirov, M. Titov, I. Tsakov, U. Uwer, C. van Eldik, Y. Vassiliev, M. Villa, A. Vitale, I. Vukotic, H. Wahlberg, A.H. Walenta, M. Walter, J.J. Wang, D. Wegener, U. Werthenbach, H. Wolters, R. Wurth, A. Wurz, Y. Zaitsev, M. Zavertyaev, T. Zeuner, A. Zhelezov, Z. Zheng, R. Zimmermann, T. Živko, A. Zoccoli, I. ABT, M. ADAMS, M. AGARI, H. ALBRECHT, A. ALEKSANDROV, V. AMARAL, A. AMORIM, S.J. APLIN, V. AUSHEV, Y. BAGATURIA, V. BALAGURA, M. BARGIOTTI, O. BARSUKOVA, J. BASTOS, J. BATISTA, C. BAUER, T.S. BAUER, A. BELKOV, I. BELOTELOV, A. BERTIN, B. BOBCHENKO, M. BÖCKER, A. BOGATYREV, G. BOHM, M. BRÄUER, M. BRUINSMA, M. BRUSCHI, P. BUCHHOLZ, T. BURAN, J. CARVALHO, P. CONDE, C. CRUSE, M. DAM, K.M. DANIELSEN, M. DANILOV, S. DE CASTRO, H. DEPPE, X. DONG, H.B. DREIS, V. EGORYTCHEV, K. EHRET, F. EISELE, D. EMELIYANOV, S. ESSENOV, L. FABBRI, P. FACCIOLI, M. FEUERSTACK-RAIBLE, J. FLAMMER, B. FOMINYKH, M. FUNCKE, L. GARRIDO, A. GELLRICH, B. GIACOBBE, J. GLÄß, D. GOLOUBKOV, Y. GOLUBKOV, A. GOLUTVIN, I. GOLUTVIN, I. GORBOUNOV, A. GORISEK, O. GOUCHTCHINE, D.C. GOULART, S. GRADL, W. GRADL, F. GRIMALDI, J. GROTH-JENSEN, Y. GUILITSKY, J.D. HANSEN, J.M. HERNÁNDEZ, W. HOFMANN, M. HOHLMANN, T. HOTT, W. HULSBERGEN, U. HUSEMANN, O. IGONKINA, M. ISPIRYAN, T. JAGLA, C. JIANG, H. KAPITZA, S. KARABEKYAN, N. KARPENKO, S. KELLER, J. KESSLER, F. KHASANOV, Y. KIRYUSHIN, I. KISEL, E. KLINKBY, K.T. KNÖPFLE, H. KOLANOSKI, S. KORPAR, C. KRAUSS, P. KREUZER, P. KRIZAN, D. KRÜCKER, S. KUPPER, T. KVARATSKHELIIA, A. LANYOV, K. LAU, B. LEWENDEL, T. LOHSE, B. LOMONOSOV, R. MÄNNER, R. MANKEL, S. MASCIOCCHI, I. MASSA, I. MATCHIKHILIAN, G. MEDIN, M. MEDINNIS, M. MEVIUS, A. MICHETTI, Y. MIKHAILOV, R. MIZUK, R. MURESAN, M. ZUR NEDDEN, M. NEGODAEV, M. NÖRENBERG, S. NOWAK, M.T. NÚÑEZ PARDO DE VERA, M. OUCHRIF, F. OULD-SAADA, C. PADILLA, D. PERALTA, R. PERNACK, R. PESTOTNIK, B.A. PETERSEN, M. PICCININI, M.A. PLEIER, M. POLI, V. POPOV, D. POSE, S. PRYSTUPA, V. PUGATCH, Y. PYLYPCHENKO, J. PYRLIK, K. REEVES, D. REßING, H. RICK, I. RIU, P. ROBMANN, I. ROSTOVTSEVA, V. RYBNIKOV, F. SÁNCHEZ, A. SBRIZZI, M. SCHMELLING, B. SCHMIDT, A. SCHREINER, H. SCHRÖDER, U. SCHWANKE, A.J. SCHWARTZ, A.S. SCHWARZ, B. SCHWENNINGER, B. SCHWINGENHEUER, F. SCIACCA, N. SEMPRINI-CESARI, S. SHUVALOV, L. SILVA, L. SÖZÜER, S. SOLUNIN, A. SOMOV, S. SOMOV, J. SPENGLER, R. SPIGHI, A. SPIRIDONOV, A. STANOVNIK, M. STARIC, C. STEGMANN, H.S. SUBRAMANIA, M. SYMALLA, I. TIKHOMIROV, M. TITOV, I. TSAKOV, U. UWER, C. VAN ELDIK, Y. VASSILIEV, M. VILLA, A. VITALE, I. VUKOTIC, H. WAHLBERG, A.H. WALENTA, M. WALTER, J.J. WANG, D. WEGENER, U. WERTHENBACH, H. WOLTERS, R. WURTH, A. WURZ, Y. ZAITSEV, M. ZAVERTYAEV, T. ZEUNER, A. ZHELEZOV, Z. ZHENG, R. ZIMMERMANN, T. ZIVKO, A. ZOCCOLI, PRT, GBR, CZE, SWE, DEU, NOR, USA, SVN, CHE, DZA, BGR, DNK, RUS, NLD, DIP. DI FISICA, DIPARTIMENTO DI FISICA E ASTRONOMIA 'AUGUSTO RIGHI', Facolta' di INGEGNERIA, SECONDA FACOLTA' DI INGEGNERIA DELL'UNIVERSITA' DI BOLOGNA CON SEDE CESENA, Da definire, and AREA MIN. 02 - Scienze fisiche

Subjects
PA CROSS SECTION, Physics, Strange quark, Particle physics, HADROPRODUCTION, Physics and Astronomy (miscellaneous), Proton, Meson, 010308 nuclear & particles physics, Nuclear Theory, Sigma, HERA, Phi meson, 01 natural sciences, High Energy Physics - Experiment, 0103 physical sciences, ddc:530, High Energy Physics::Experiment, Rapidity, Atomic number, Nuclear Experiment, 010306 general physics, Engineering (miscellaneous)
Abstract

The inclusive production cross sections of the strange vector mesons K*0, K*0bar, and phi have been measured in interactions of 920 GeV protons with C, Ti, and W targets with the HERA-B detector at the HERA storage ring. Differential cross sections as a function of rapidity and transverse momentum have been measured in the central rapidity region and for transverse momenta up to pT=3.5 GeV/c. The atomic number dependence is parametrised as sigma(pA) = sigma(pN)*A**alpha, where sigma(pN) is the proton-nucleon cross section. Within the phase space accessible, alpha(K*0) = 0.86+/-0.03, alpha(K*0bar) = 0.87+/-0.03, and alpha(phi) = 0.96+/-0.02. The total proton-nucleon cross sections, determined by extrapolating the differential measurements to full phase space, are sigma(pN->K*0) = 5.06+/-0.54 mb, sigma(pN->K*0bar) = 4.02+/-0.45 mb, and sigma(pN->phi) = 1.17+/-0.11 mb. The Cronin effect is observed for the first time for vector mesons containing strange quarks; compared to the measurements of Cronin et al. for K+- mesons, the measured values of alpha for phi mesons coincide with those of K- mesons for all transverse momenta, while the enhancement for K*0 / K*0bar mesons is smaller., Comment: 19 pages, 17 figures, submitted to Eur Phys J C

Published
2007
Full Text
View/download PDF

5. The outer tracker detector of the HERA-B experiment. Part III: Operation and performance

Author

Z. Ke, O. Steinkamp, C. Stegmann, M. Ouchrif, G. Evgrafov, W. Hulsbergen, T. Buran, B. Schmidt, C. Padilla, R. Eckmann, A. S. Schwarz, R. Wurth, Jinghui Yang, R. Pernack, A. Moshkin, Yunpeng Liu, Yu.T. Kiryushin, Dmitry Emeliyanov, S. Nowak, M. Walter, Z. Zhu, M. Beck, G. Medin, I. Golutvin, A. Lanyov, Z. Zheng, I. Vukotic, M. Capeans, S. Vassiliev, A. Petrukhin, G. Bohm, Hermann Kolanoski, K. Berkhan, R. Mankel, D. Pose, Marcus Hohlmann, R. Zimmermann, J. Ni, Y. Jia, U. Uwer, I. Siccama, E. Michel, S. Karabekyan, Y. Wang, H. Schröder, N. Tesch, Th.S. Bauer, H. Albrecht, H. Deckers, S. Somov, B.X. Chen, X. Dong, C. Jiang, A. Spiridonov, J.J. Wang, V. Souvorov, A. Schreiner, U. Schwanke, K. Höpfner, S. Solunin, D. Krücker, D. Vishnevsky, H. Kapitza, K. Smirnov, I. Tsakov, M. Bruinsma, and T. Lohse

Subjects
Physics, Nuclear and High Energy Physics, Physics - Instrumentation and Detectors, Physics::Instrumentation and Detectors, business.industry, Hadron, Detector, Resolution (electron density), FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), Nuclear physics, Momentum, Optics, Planar, Gas gain, Calibration, High Energy Physics::Experiment, ddc:530, business, Instrumentation, HERA-B
Abstract

In this paper we describe the operation and performance of the HERA-B Outer Tracker, a 112674 channel system of planar drift tube layers. The performance of the HERA-B Outer Tracker system fullfilled all requirements for stable and efficient operation in a hadronic environment, thus confirming the adequacy of the honeycomb drift tube technology and of the front-end readout system. The detector was stably operated with a gas gain of 30000 in an Ar/CF4/CO2 (65:30:5) gas mixture, yielding a good efficiency for triggering and track reconstruction, larger than 95 % for tracks with momenta above 5 GeV/c. The hit resolution of the drift cells was 300 to 320 micrometers and the relative momentum resolution can be described as: sigma(p)/p (in %) = (1.61 +- 0.02) + (0.0051 +- 0.0006) p. At the end of the HERA-B running no aging effects in the Outer Tracker cells were observed., Comment: 38 pages, 20 figures. v2: Added clarifications about trigger efficiency, momentum resolution and alignment precision. Corrected typos. Improved figure quality

Published
2007
Full Text
View/download PDF

6. Polarization of Λ and Λ¯ in 920 GeV fixed-target proton–nucleus collisions

Author

I. Abt, M. Adams, M. Agari, H. Albrecht, A. Aleksandrov, V. Amaral, A. Amorim, S.J. Aplin, V. Aushev, Y. Bagaturia, V. Balagura, M. Bargiotti, O. Barsukova, J. Bastos, J. Batista, C. Bauer, Th.S. Bauer, A. Belkov, Ar. Belkov, I. Belotelov, A. Bertin, B. Bobchenko, M. Böcker, A. Bogatyrev, G. Bohm, M. Bräuer, M. Bruinsma, M. Bruschi, P. Buchholz, T. Buran, J. Carvalho, P. Conde, C. Cruse, M. Dam, K.M. Danielsen, M. Danilov, S. De Castro, H. Deppe, X. Dong, H.B. Dreis, V. Egorytchev, K. Ehret, F. Eisele, D. Emeliyanov, S. Erhan, S. Essenov, L. Fabbri, P. Faccioli, M. Feuerstack-Raible, J. Flammer, B. Fominykh, M. Funcke, Ll. Garrido, A. Gellrich, B. Giacobbe, J. Gläß, D. Goloubkov, Y. Golubkov, A. Golutvin, I. Golutvin, I. Gorbounov, A. Gorišek, O. Gouchtchine, D.C. Goulart, S. Gradl, W. Gradl, F. Grimaldi, Yu. Guilitsky, J.D. Hansen, J.M. Hernández, W. Hofmann, M. Hohlmann, T. Hott, W. Hulsbergen, U. Husemann, O. Igonkina, M. Ispiryan, T. Jagla, C. Jiang, H. Kapitza, S. Karabekyan, N. Karpenko, S. Keller, J. Kessler, F. Khasanov, Yu. Kiryushin, I. Kisel, E. Klinkby, K.T. Knöpfle, H. Kolanoski, S. Korpar, C. Krauss, P. Kreuzer, P. Križan, D. Krücker, S. Kupper, T. Kvaratskheliia, A. Lanyov, K. Lau, B. Lewendel, T. Lohse, B. Lomonosov, R. Männer, R. Mankel, S. Masciocchi, I. Massa, I. Matchikhilian, G. Medin, M. Medinnis, M. Mevius, A. Michetti, Yu. Mikhailov, R. Mizuk, R. Muresan, M. zur Nedden, M. Negodaev, M. Nörenberg, S. Nowak, M.T. Núñez Pardo de Vera, M. Ouchrif, F. Ould-Saada, C. Padilla, D. Peralta, R. Pernack, R. Pestotnik, B.AA. Petersen, M. Piccinini, M.A. Pleier, M. Poli, V. Popov, D. Pose, S. Prystupa, V. Pugatch, Y. Pylypchenko, J. Pyrlik, K. Reeves, D. Reßing, H. Rick, I. Riu, P. Robmann, I. Rostovtseva, V. Rybnikov, F. Sánchez, A. Sbrizzi, M. Schmelling, B. Schmidt, A. Schreiner, H. Schröder, U. Schwanke, A.J. Schwartz, A.S. Schwarz, B. Schwenninger, B. Schwingenheuer, F. Sciacca, N. Semprini-Cesari, S. Shuvalov, L. Silva, L. Sözüer, S. Solunin, A. Somov, S. Somov, J. Spengler, R. Spighi, A. Spiridonov, A. Stanovnik, M. Starič, C. Stegmann, H.S. Subramania, M. Symalla, I. Tikhomirov, M. Titov, I. Tsakov, U. Uwer, C. van Eldik, Yu. Vassiliev, M. Villa, A. Vitale, I. Vukotic, H. Wahlberg, A.H. Walenta, M. Walter, J.J. Wang, D. Wegener, U. Werthenbach, H. Wolters, R. Wurth, A. Wurz, Yu. Zaitsev, M. Zavertyaev, T. Zeuner, A. Zhelezov, Z. Zheng, R. Zimmermann, T. Živko, and A. Zoccoli

Subjects
Physics, Nuclear and High Energy Physics, Spectrometer, 010308 nuclear & particles physics, Polarization (waves), 01 natural sciences, Baryon, Nuclear physics, medicine.anatomical_structure, 0103 physical sciences, Transverse momentum, medicine, High Energy Physics::Experiment, Statistical error, Nuclear Experiment, 010306 general physics, Nucleus, HERA-B
Abstract

A measurement of the polarization of Λ and Λ ¯ baryons produced in pC and pW collisions at s = 41.6 GeV has been performed with the HERA-B spectrometer. The measurements cover the kinematic range of 0.6 GeV / c p ⊥ 1.2 GeV / c in transverse momentum and − 0.15 x F 0.01 in Feynman-x. The polarization results from the two different targets agree within the statistical error. In the combined data set, the largest deviation from zero, + 0.054 ± 0.029 , is measured for x F ≲ − 0.07 . Zero polarization is expected at x F = 0 in the absence of nuclear effects. The polarization results for the Λ agree with a parametrization of previous measurements which were performed at positive x F values, where the Λ polarization is negative. Results of Λ ¯ polarization measurements are consistent with zero.

Published
2006
Full Text
View/download PDF

7. Observations on cathode aging (Malter effect) in honeycomb drift chambers under high irradiation load

Author

G. Bohm, Hermann Kolanoski, V. Souvorov, A. Schreiner, K. Berkhan, U. Schwanke, M. Walter, C. Stegmann, and U. Uwer

Subjects
Physics, Nuclear and High Energy Physics, Physics::Instrumentation and Detectors, business.industry, Detector, Cathode, law.invention, Ignition system, Optics, Malter effect, Physics::Plasma Physics, law, Radiation damage, Honeycomb, Physics::Accelerator Physics, High Energy Physics::Experiment, Irradiation, Composite material, business, Instrumentation, FOIL method
Abstract

The Outer Tracking (OTR) system for the HERA-B detector at DESY consists of honeycomb drift tubes with cathodes folded from Pokalon-C foil, a soot-containing polycarbonate, operating with CF 4 -containing drift gas. The first prototypes, exposed to radiation in HERA-B, suffered radiation damage ascribed to the Malter effect (ignition of self-sustaining discharges). We present the results of investigations of cathode surface properties and include a semiquantitative discussion of the ion-layer formation process. The achieved understanding was important for the development of a radiation-hard detector.

Published
2003
Full Text
View/download PDF

8. Humidity dependence of anode corrosion in HERA-B Outer Tracker Chambers operated with Ar/CF4/CO2

Author

A. Schreiner, G. Bohm, Hermann Kolanoski, and M. Walter

Subjects
Physics, Nuclear and High Energy Physics, Analytical chemistry, Conductivity, Cathode, Dissociation (chemistry), law.invention, Anode, Corrosion, Malter effect, law, Irradiation, Instrumentation, HERA-B
Abstract

The Outer Tracker of the HERA-B experiment consists of drift tubes folded from gold-coated polycarbonate foils (honeycomb) and is operated with the gas mixture Ar/CF 4 /CO 2 . The choice of the materials and the drift gas was the result of an extended R&D program launched to avoid both anode aging (gain loss) and cathode aging (Malter effect). However, other aging effects were observed at high irradiation doses: rising conductivity of the wire-supporting strips and wire corrosion. In this paper, we show that these two aging effects could also be prevented by keeping water at a proper concentration (about 300 ppm ). In an attempt to interpret the test results, the production and reaction probability of molecular species produced via CF 4 dissociation in the avalanche are semi-quantitatively estimated.

Published
2003
Full Text
View/download PDF

9. Inclusive V production cross sections from 920 GeV fixed target proton-nucleus collisions

Author

Imma Riu, F. Sanchez, Hernan Wahlberg, L. Garrido, B. Bobchenko, N. Tesch, Brian Petersen, I. Kisel, C. Stegmann, C. B. Krauss, Mikhail Zavertyaev, O. Barsukova, J. L. Rosen, O. Steinkamp, Ulrich Werthenbach, D. Ryzhikov, F. Klefenz, D. Dujmic, I. Belotelov, H. Kapitza, H. Thurn, Yu. Pavlenko, P. Kreuzer, Jenny Ivarsson, Pietro Faccioli, M. Beck, I. Golutvin, V. Aushev, R. Wurth, T. Perschke, Mauro Villa, D. Broemmelsiek, M. Chmeissani, H. Sun, J. Yang, A. Michetti, Paul Edmund Karchin, A. Stanovnik, H. Fleckenstein, M. Ouchrif, S. Korpar, J. Luidemann, M. Spahn, K. Hofner, A. Kaoukher, Helmut Wolters, V. Saveliev, L. Sozuer, V. Vagnoni, J. Chamanina, A. Bogatyrev, Farid Ould-Saada, Kwong Lau, B. Lewende, M. Mevius, Yu.V. Mikhailov, L. Seybold, Ramon Miquel, J. D. Hansen, Søren Schmidt, Peter Robmann, Wolfgang Wagner, R. van Staa, R Stdenis, S. Hausmann, R. Chistov, D. Samtleben, B. Lomonosov, K. Berkhan, V. Rusinov, V. Eiges, M. Medinnis, D. C. Goulart, Dmitry Emeliyanov, S. Schaller, Z. Ke, I. Belyaev, A. Zhelezov, Samim Erhan, W. Ruckstuhl, A. Moshkin, V. Popov, Werner Hofmann, P.E. Schlein, J. Glass, R. F. Schwitters, Valery Pugatch, S. Essenov, J.J. Wang, D. Wegener, J. Rieling, Roberto Spighi, R. Mankel, A. Lange, D. Krücker, S. Nowak, D. Pose, J. Bastos, A. Belkov, Hyun-Chul Kim, N.N. Karpenko, W. Schmidt-Parzefall, Umberto Marini Bettolo Marconi, S. Steinbeck, V. Souvorov, A. Schreiner, Thomas Hamacher, B. Dolgoshein, W. Gradl, M. A. Pleier, C. Borgmeier, A. S. Schwarz, K. T. Knöpfle, B. Schwenninger, K. E. K. Gerndt, Antonio Zoccoli, Y. Guilitsky, Y. Vassiliev, U. Straumann, Yu.T. Kiryushin, I. Gorbounov, F. Saadi-Ludemannm, M. Dressel, M. Poli, D. Peralta, T. Lohse, I. Negri, M. Capeans, A. Bertin, Antonio Sbrizzi, Z. Zheng, S. Karabekyan, Y. Bagaturia, S. Ramachandran, G. Leffers, A. Vitale, I. Vukotic, S. Semenov, J. Zweizig, K. M. Danielsen, Benedetto Giacobbe, A. Gellrich, X. Dong, S. Shuvalov, Reinhard Männer, B. Schwingenheuer, B. Fominykh, F. Khasanov, M. Nörenberg, V. Rybnikov, M. Funcke, M. Walter, Nicola Semprini-Cesari, M. Bruinsma, M. Bargiotti, P. Pakhlov, C. van Eldik, H. Deppe, David Gascon, M. Hildebrandt, Kendall Reeves, I. C. Legrand, Vasco Amaral, S. Fourletov, M. Rietz, J. Shiu, O. Gouchtchine, J. Pyrlik, S. Solunin, W. Fallot-Burghardt, S. Keller, S. F. Takach, Christian Bauer, T. Glebe, Andrej Gorišek, D. Galli, H. Schröder, M. Ispiryan, M. Titov, G. Bohm, V. Bassetti, T. Fuljahn, Hermann Kolanoski, L. Matchikhilian, F Sciacca, Klaus Dehmelt, S. Gradl, R. Pernack, S. Issever, H. Itterbeck, V. Kochetkov, T. Zeuner, D. Skrk, I. Abt, B. X. Chen, M. Sang, P. Truöl, W. Hulsbergen, R. Baghshetsyan, P. J. Weyers, R. Wanke, J. Spengler, B. Schmidt, K. Ehret, Yuriy Pylypchenko, R. Pestotnik, Y. Jia, T. Buran, R. Loke, F. Sun, Ulrich Husemann, J. Flammer, M. Böcker, A. Pose, C. Jiang, A. Spiridonov, A. Christensen, M. Symalla, R. Eckmann, A. Golutvin, S. J. Aplin, João Carvalho, U. Trunk, M. S. Atiya, I. Tsakov, S. Nam, Olga Igonkina, V. Balagura, R. Muresan, M. Feuerstack-Raible, Y. Wang, C. Hast, G. Zech, A. Mohapatra, H. B. Dreis, M. Buchler, Mogens Dam, I. Arino, R. Mizuk, U. Schwanke, Laura Fabbri, S. De Castro, M. Danilov, P. Krizan, S. Masciocchi, A. H. Walenta, D. Goloubkov, K. Riechmann, B. Moshous, A. Lanyov, G. Medin, Z. Zhu, H. Deckers, A. Soldatov, T. Zivko, Marcus Hohlmann, A. Arefiev, F. Ratnikov, I. Tikhomirov, H. Albrecht, R. Zimmermann, I. Massa, A. Garcia, R. F. Harr, M. T. N. P. de Vera, T. Oest, D. Ressing, V. Egorytchev, A. Oliveira, A. Wurz, M. Bräuer, C. Rothe, H. D. Schultz, António Amorim, Peter Buchholz, T. Kvaratskheliia, Th.S. Bauer, T. Walter, M. Starič, A. Somov, M. Adams, E. Sexauer, M. Negodaev, Yang Liu, A. J. Schwartz, D. Stieler, Jose M Hernandez, M. Bruschi, M. Piccinini, A. Hoscher, G.J. Wagner, I. Siccama, M. Schmelling, S. Barsuk, S. Spratte, F. Eisele, M. Capponi, T. Hott, P. Conde, T. Jagla, S. Somov, Yu. Zaitsev, C. Cruse, C. Padilla, S. Xella-Hansen, A. Abyzov, and U. Uwer

Subjects
Physics, Physics and Astronomy (miscellaneous), Proton, 010308 nuclear & particles physics, Sigma, HERA, Lambda, 7. Clean energy, 01 natural sciences, Atomic mass, Nuclear physics, 0103 physical sciences, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, Nucleon, 010303 astronomy & astrophysics, Engineering (miscellaneous), HERA-B, Bar (unit)
Abstract

Inclusive differential cross sections dsigma(pA)/dx(F) and dsigma(pA)/dp(t)(2) for the production of K-S(0), Lambda, and (U) over bar particles are measured at HERA in proton-induced reactions on C, Al, Ti, and W targets. The incident beam energy is 920 GeV, corresponding to roots = 41.6 GeV in the proton-nucleon system. The ratios of differential cross sections dsigma(pA)(K-S(0))/dsigma(pA)(Lambda) and dsigma(pA)((U) over bar)/dsigma(pA) (Lambda) are measured to be 6.2 +/- 0.5 and 0.66 +/- 0.07, respectively, for x(F) approximate to -0.06. No significant dependence upon the target material is observed. Within errors, the slopes of the transverse momentum distributions da,Ald t also show no significant dependence upon the target material. The dependence of the extrapolated total cross sections sigma(pA) on the atomic mass A of the target material is discussed, and the deduced cross sections per nucleon sigma(pN) are compared with results obtained at other energies.

Published
2003
Full Text
View/download PDF

10. J/psi production via chi(c) decays in 920 GeV pA interactions

Author

Samim Erhan, P. Kreuzer, M. Noerenberg, M. T. Nunez Pardo de Vera, R. Muresan, B. Schmidt, L. Garrido, H. B. Dreis, K. Berkhan, T. Hott, A. Stanovnik, U. Uwer, Sebastian Nowak, V. Rusinov, D. Wegener, R. Mizuk, C. Borgmeier, W. Gradl, M. Walter, D. Ryzhikov, Peter Robmann, M. Hildebrandt, S. Schmidt, B. A. Petersen, V. Saveliev, O. Gouchtchine, R. vanStaa, K. Riechmann, J. Yang, Pietro Faccioli, I. Massa, V. Aushev, J.D. Hansen, M. Spahn, C. Cruse, H. Wahlberg, D. Dujmic, J. Glaess, G. Bohm, C. Hast, Hermann Kolanoski, M. Dressel, A. Somov, G. Medin, J. Chamanina, J. Zweizig, P.E. Schlein, K. M. Danielsen, R. F. Schwitters, R. Eckmann, P. Conde, D. Kruecker, Igor Golutvin, M. Boecker, T. Jagla, S. Schaller, A. Moshkin, R. Wanke, A. Zhelezov, Yu. Zaitsev, Y. Pylypchenko, O. Steinkamp, T. Zivko, L. Sozuer, F. Sanchez, Jenny Ivarsson, M. Capponi, D. Goloubkov, K. T. Knöpfle, Kwong Lau, A. Gellrich, W. Schmidt-Parzefall, R. Spighi, Thomas Hamacher, Y. Vassiliev, I. Negri, G. Leffers, Rok Pestotnik, M. Symalla, S. J. Aplin, H. Schroeder, S. Essenov, A. Michetti, Paul Edmund Karchin, Y. Guilitsky, S. Steinbeck, S. Solunin, W. Fallot-Burghardt, U. Werthenbach, Yu.V. Mikhailov, A. Kaoukher, G.J. Wagner, B. Lewendel, David Gascon, S. F. Takach, M. Titov, T. Zeuner, A. H. Walenta, Y. Wang, J. Spengler, A. Belkov, L. Matchikhilian, O. Barsukova, S. Karabekyan, R Stdenis, U. Trunk, A. J. Schwartz, D. Stieler, Jose M Hernandez, I. Siccama, I. Abt, H. Itterbeck, Ramon Miquel, R. Baghshetsyan, D. C. Goulart, D. Galli, V. Popov, Werner Hofmann, Imma Riu, Mikhail Zavertyaev, B. Dolgoshein, V. Kochetkov, Ch. Rothe, B. Schwenninger, B. Giacobbe, S. Shuvalov, B. Bobchenko, M. Capeans, Yu. Pavlenko, Hyun-Chul Kim, A. Arefiev, S. De Castro, A. Wurz, Yu.T. Kiryushin, Laura Fabbri, L. Seybold, A. Lanyov, F. Klefenz, B. Lomonosov, V. Eiges, M. Feuerstack-Raible, C. Jiang, A. Spiridonov, V. Rybnikov, A. Golutvin, C. Padilla, W. Ruckstuhl, F. Ratnikov, I. Tikhomirov, S. Nam, Nicola Semprini-Cesari, Mauro Villa, M. Schmelling, M. A. Pleier, K. Höpfner, A. Christensen, Y. Bagaturia, Christian Bauer, D. Peralta, V. Bassetti, R. Wurth, B. Moshous, U. Schwanke, P. Truöl, C. B. Krauss, T. Oest, S. Barsuk, Samo Korpar, M. Poli, M. Adams, N. Tesch, U. Marconi, Fouzia Saadi-Lüdemann, Antonio Zoccoli, Jian Wang, M. Chmeissani, João Carvalho, Antonio Sbrizzi, J. Lüdemann, S. Spratte, E. Sexauer, D. Ressing, F. Khasanov, Robert Harr, S. Hausmann, I. Vukotic, S. Xella-Hansen, A. Bogatyrev, M. Bruinsma, U. Husemann, M. Negodaev, Kendall Reeves, T. Glebe, S. Fourletov, V. Souvorov, J. Bastos, T. Buran, I. Kisel, M. Buchler, I. Belyaev, Maurizio Piccinini, Y. Goloubkov, A. Gorisek, Dmitry Emeliyanov, T. Perschke, I. Tsakov, S. Gradl, A. Schreiner, S. Ramachandran, S. Keller, Vasco Amaral, X. Chen, F Sciacca, Klaus Dehmelt, Mogens Dam, X. Dong, R. Pernack, S. Issever, M. Sang, A. S. Schwarz, Th. S. Bauer, J. L. Rosen, A. Bertin, K. Ehret, N.N. Karpenko, D. Broemmelsiek, P. J. Weyers, R. Loke, K. E. K. Gerndt, Yunpeng Liu, Peter Buchholz, B. Schwingenheuer, A. Pose, W. Hulsbergen, Y. Jia, Z. Zheng, Marco Bruschi, A. Holscher, T. Walter, Thomas Lohse, J. Pyrlik, F. Eisele, A. Soldatov, Marcus Hohlmann, S. Somov, M. Ispiryan, J. Flammer, M. Bargiotti, B. Fominykh, Helmut Wolters, Farid Ould-Saada, M. Ouchrif, I. Arino, Wolfgang Wagner, M. Beck, Olga Igonkina, R. Zimmermann, P. Krizan, V. Balagura, H. Deckers, M. Danilov, I. Gorbounov, G. Zech, A. Mohapatra, T. Kvaratskheliia, R. Mankel, M. Funcke, I. C. Legrand, H. Albrecht, M. Starič, D. Skrk, V. Egorytchev, A. Oliveira, A. Lange, D. Pose, M. Braeuer, Mike Medinnis, C. van Eldik, Z. Ke, H. Deppe, J. Rieling, H. D. Schultz, Vincenzo Vagnoni, M. Rietz, C. Stegmann, A. Vitale, S. Semenov, António Amorim, T. Fuljahn, A. Garcia, R. Maenner, M. Mevius, H. Fleckenstein, R. Chistov, D. Samtleben, I. Belotelov, H. Kapitza, H. Thurn, Valery Pugatch, M. S. Atiya, S. Masciocchi, Z. Zhu, Geometry, (Astro)-Particles Physics, Mathematical Analysis, and Business Web and Media

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, 01 natural sciences, 7. Clean energy, High Energy Physics - Experiment, Nuclear physics, 0103 physical sciences, Radiative transfer, High Energy Physics::Experiment, 010306 general physics, Nuclear Experiment, HERA-B
Abstract

Using data collected by the HERA-B experiment, we have measured the fraction of J\psi's produced via radiative chi_c decays in interactions of 920 GeV protons with carbon and titanium targets. We obtained R_{\chi_c} = 0.32 \pm 0.06_{stat} \pm 0.04_{sys} for the fraction of J\psi from chi_c decays averaged over proton-carbon and proton-titanium collisions. This result is in agreement with previous measurements and is compared with theoretical predictions., Comment: 16 pages, 5 figs

Published
2003
Full Text
View/download PDF

11. High-performance 5.5 μm quantum cascade lasers with high-reflection coating

Author

N. Ulbrich, A. Sigl, G. Scarpa, M.-C. Amann, G. Abstreiter, G. Bohm, and Jürgen Rosskopf

Subjects
Materials science, Computer Networks and Communications, business.industry, engineering.material, Liquid nitrogen, Laser, Atomic and Molecular Physics, and Optics, law.invention, Reflection (mathematics), Optics, Coating, Cascade, law, Optical cavity, engineering, Optoelectronics, Electrical and Electronic Engineering, business, Quantum, Lasing threshold
Abstract

A high-reflection coating for 5.5 µm strain-compensated InGaAs/InAlAs quantum cascade lasers is described. Using a high-reflection coating on both facets of a laser cavity, a threshold current density of 0.5 kA/cm2 was observed at liquid-nitrogen temperature, whereas for an uncoated structure of comparable length the threshold current density was 1 kA/cm2. Laser action for a 2.1 mm long and 30 µm wide device with coated facets was achieved in pulsed mode up to the record high temperature of 470 K. A 2.5 mm long and 30 µm wide device with uncoated facets shows lasing action up to 440 K.

Published
2002
Full Text
View/download PDF

12. Short-Cavity Long-Wavelength VCSELs With Modulation Bandwidths in Excess of 15 GHz

Author

Michael Muller, Markus-Christian Amann, Werner Hofmann, and G. Bohm

Subjects
Materials science, business.industry, Bandwidth (signal processing), Optical communication, Dielectric, Laser, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, law.invention, Semiconductor laser theory, Long wavelength, Optics, Tunnel junction, law, Fiber laser, Optoelectronics, Electrical and Electronic Engineering, business
Abstract

InP-based buried tunnel junction vertical-cavity surface-emitting lasers (VCSELs) incorporating a novel short-cavity (SC) design are presented. These highly single-mode devices emitting at 1.55 mum show record-high modulation bandwidths in excess of 15 GHz together with greatly enhanced intrinsic resonance frequencies. For elevated temperatures of 65degC and 80degC, 3-dB-modulation bandwidths beyond 13 and 10 GHz are demonstrated, respectively. Reasons for the improved modulation behavior are the smaller intrinsic damping due to reduced photon-lifetime, and the better heat-management of these SC-VCSELs.

Published
2009
Full Text
View/download PDF

13. Focus on glaciers: a geo-photo exposition of vanishing beauty

Author

G. Rossi, G. Böhm, A. Saraò, D. Cotterle, L. Facchin, P. Giurco, R. G. Lucchi, M. E. Musco, F. Petrera, S. Picotti, and S. Salon

Subjects
Geography. Anthropology. Recreation, Science
Abstract

Scientific research, respect for the environment, and passion for photography merged into an exceptional heritage of images collected by the researchers and technicians of the National Institute of Oceanography and Applied Geophysics (OGS). The images were taken during past scientific expeditions conducted all over the world to widen scientific knowledge in the fields of Earth and ocean sciences, to raise awareness on the environment and conservation of natural resources, and to mitigate natural risks. In this paper, we describe a photographic exhibition organized using some of the OGS images to draw public attention to the striking effects of global warming. In the artistic images displayed, the glaciers were the protagonists. Their infinite greyish blue shades and impossible shapes were worthy of a great sculptor, and the boundaries with rocks or with the sea were sometimes sharp and dramatic and sometimes so nuanced that they looked like watercolours. The beauty of the images attracted the attention of the public to unknown realities, allowing us to document the dramatic retreat of the Alpine glaciers and to show the majesty of the Arctic and Antarctic landscapes, which are fated to vanish under the present climate warming trend. The choice of the exhibition location allowed us to reach a broad public of working-age adults, who are difficult to involve in outreach events. The creators of the images were present during the exhibition to respond to visitors' curiosity about research targets, the emotional and environmental context, and the technical details or aesthetic choices of the photographs.

Published
2020
Full Text
View/download PDF

14. Progress in mask technology for ion implantation based nanofabrication

Author

U. A. Griesinger, A. Menschig, G. Weimann, Günther Tränkle, M. Burkard, G. Bohm, Heinz Schweizer, and H. Klein

Subjects
Nanolithography, Fabrication, Photoluminescence, Ion implantation, Quantum dot, General Engineering, Nanotechnology, Nanometre, Electroplating, Blueshift
Abstract

Gold dot implantation masks with diameters down to 45 nm have been defined using a liftoff process and have been used to fabricate GaAs/AlGaAs quantum dots by the technique of masked‐implantation‐enhanced intermixing (MIEI). The photoluminescence of these quantum dots shows a high intensity down to the smallest diameters and a systematic blueshift due to the quantum size effect. Furthermore, a novel nanometer electroplating (NEP) technique for the fabrication of gold dot implantation masks down to 30 nm with high aspect ratios (≳1:3) is presented. It is expected that the NEP masks are superior to the liftoff masks for future application of the MIEI technique.

Published
1994
Full Text
View/download PDF

15. Modulation-doped InAlAs/InGaAs quantum well structures for high electron mobility transistors

Author

Günther Tränkle, G. Weimann, S. Grigull, H. Heiss, M. Sexl, G. Bohm, and W. Klein

Subjects
Electron mobility, Photoluminescence, Materials science, Condensed matter physics, business.industry, Transconductance, Doping, General Engineering, Heterojunction, Optoelectronics, Field-effect transistor, business, Quantum well, Molecular beam epitaxy
Abstract

Modulation‐doped InAlAs/InGaAs heterostructures were grown on InP substrates by solid source molecular beam epitaxy. Lattice matching within ±10−3 was reproducibly obtained. The high quality of the ternary compounds is demonstrated by narrow photoluminescence linewidths of full width at half‐maximum=2 and 13 meV for InGaAs and InAlAs, respectively. The transport properties are excellent, too, with a 4.2 K mobility of 84 000 cm2/Vs for two‐dimensional electron gas concentrations of 1.3×1012 cm−2 in conventional single heterostructures. Optimized single quantum‐well structures with high current carrying capacity due to modulation doping in both barriers have sheet carrier concentrations of 4.0×1012 cm−2 and 4.2 K mobilities of 28 000 cm2/Vs. Sub‐μm‐high electron mobility transistors processed from these structures show a maximum transconductance of 500 mS/mm at a drain current of 445 mA/mm. A very high maximum drain current of 1120 mA/mm is obtained, while maintaining cutoff frequencies of fT=118 GHz and fm...

Published
1994
Full Text
View/download PDF

16. Drift wave spectra at the WIIA-stellarator

Author

H Schluter, G Luthen, G Derra, L Schmitz, and G Bohm

Subjects
Physics, Gyroradius, Condensed Matter Physics, Omega, Spectral line, law.invention, Ion, Amplitude, Classical mechanics, Nuclear Energy and Engineering, law, Diamagnetism, Atomic physics, Test particle, Stellarator
Abstract

Large amplitude drift wave fluctuations have been investigated in a 1=2 stellarator with very low shear (Ls/Ln>or=600). Considerable broadening and decorrelation of the linear unstable modes omega k approximately omega e*(k) ( omega e*(k)=kperpendicular to (kBTe/eB). Del ne/ne being the diamagnetic drift frequency) due to nonlinear wave-wave coupling is observed ( Delta omega k approximately= omega k). The resulting saturated turbulent spectrum shows some evidence for an inverse cascade process transferring wave energy from the most unstable modes to lower kperpendicular to (kperpendicular to rho s approximately=0.1 according to linear theory, rho s=(kTe/mi)12// omega ci being the effective ion gyroradius). A rather high saturation level ( delta n/n)2

Published
1985
Full Text
View/download PDF

17. Gas ionization on the axis of a circular waveguide

Author

B. Kampmann, H. Beerwald, and G Bohm

Subjects
Physics, Acoustics and Ultrasonics, business.industry, Plasma, Condensed Matter Physics, Circular waveguide, Omega, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Magnetic field, Optics, Cylindrical waveguide, Ionization, Electric field, Magnetic pressure, Atomic physics, business
Abstract

The gas ionization in a cylindrical waveguide by means of the E01 mode is investigated. The possibility of generating a pulsed discharge concentrated at the axis is demonstrated. The experiments are carried out for the case of zero magnetic field and the case of a strong axial magnetic field ( omega c2>> omega 2).

Published
1976
Full Text
View/download PDF

18. MEMS-tunable 1.55-μm VCSEL with extended tuning range incorporating a buried tunnel junction.

Author

M. Maute, B. Kogel, G. Bohm, P. Meissner, and M.-C. Amann

Abstract

We present an electrically pumped and micromechanically tunable InP-based vertical-cavity surface-emitting laser operating in the 1.55-μm wavelength range. The current confinement is achieved by a buried tunnel junction. The GaAs-based movable top mirror membrane is fabricated separately, assembled on top of the device, and can be actuated electrothermally. A single mode output power of about 1.7 mW and a tuning range of 28 nm was obtained. By the use of an antireflection coating at the semiconductor-air-interface, we were able to extend the tuning range up to 60 nm as expected from one-dimensional simulations. [ABSTRACT FROM PUBLISHER]

Published
2006
Full Text
View/download PDF

19. 10-Gb/s data transmission using BCB passivated 1.55-μm InGaAlAs-InP VCSELs.

Author

W. Hofmann, N.H. Zhu, M. Ortsiefer, G. Bohm, J. Rosskopf, L. Chao, S. Zhang, M. Maute, and M.-C. Amann

Abstract

Molecular-beam-epitaxy-grown InGaAlAs-InP vertical-cavity surface-emitting lasers with buried tunnel junction for 1.55-μm wavelength, passivated with benzocyclobutene (BCB) and coplanar contacts are presented. The devices show 3-dB modulation frequencies above 8 GHz (small signal modulation) and wide open eye diagrams up to 10 Gb/s over more than 4.6-km ITU-T G.653 fiber (data transmission experiment). [ABSTRACT FROM PUBLISHER]

Published
2006
Full Text
View/download PDF

20. 2.5-mW single-mode operation of 1.55-μm buried tunnel junction VCSELs.

Author

M. Ortsiefer, S. Baydar, K. Windhorn, G. Bohm, J. Rosskopf, R. Shau, E. Ronneberg, W. Hofmann, and M.-C. Amann

Abstract

We present 1.55-μm wavelength buried tunnel junction InGaAlAs-InP vertical-cavity surface-emitting lasers with low threshold current and high efficiency. An improved mirror design is accomplished with high-reflective low-loss epitaxial InGaAlAs-InAlAs and hybrid dielectric CaF2-ZnS-Au layer stacks, respectively. Lasers with aperture diameters of only around 5 μm exhibit continuous-wave single-mode output powers at room temperature well beyond 2 mW. Threshold voltages and series resistances as low as 0.9 V and 30-40 Ω have been measured. The spectral behavior shows excellent performance over the relevant current and temperature range. [ABSTRACT FROM PUBLISHER]

Published
2005
Full Text
View/download PDF

21. 80°C continuous-wave operation of 2.01-μm wavelength InGaAlAs-InP vertical-cavity surface-emitting lasers.

Author

C. Lauer, M. Ortsiefer, R. Shau, J. Rosskopf, G. Bohm, E. Ronneberg, F. Kohler, and M.-C. Amann

Abstract

Electrically pumped buried tunnel junction InGaAlAs-InP vertical-cavity surface-emitting lasers (VCSELs) with self-adjusted lateral current and optical confinement and record emission wavelengths beyond 2 μm are presented. Front and back side mirrors are realized using 31.5 epitaxial layer pairs of alternating InGaAs-InAlAs and a dielectric 2.5 pair CaF2-a-Si layer stack. The devices show single-mode continuous-wave operation up to heat sink temperatures over 80°C. The maximum output power at 20°C reaches 0.43 mW, threshold current and voltage are as low as 0.66 mA and 0.73 V, respectively. To reach the long emission wavelength, we use an optimized active region comprising heavily strained quantum wells. High-resolution X-ray diffraction and photoluminescence measurements reveal excellent material quality without relaxation in the quantum wells. [ABSTRACT FROM PUBLISHER]

Published
2004
Full Text
View/download PDF

23. 'Index Petrefactorum' – Ein Katalog der Petrefaktensammlung der Gesellschaft Naturforschender Freunde zu Berlin aus dem 18. Jahrhundert

Author

G. Böhme and K. Böhme

Subjects
Paleontology, QE701-760
Abstract

Ein hanndschriftlicher Sammlungskatalog im Institut für Paläontologie des Museums für Naturkunde zu Berlin, dessen Herkunft bisher unklar war, wurde als Katalog der Petrefaktensammlung der 1773 gegründeten Gesellschaft Naturforschender Freunde zu Berlin erkannt. Der Index petrefactorum aus dem Ende des 18. Jahrhunderts dokumentiert Umfang und Entwicklungsstand dieser Sammlung. Autor des Kataloges ist Friedrich Wilhelm Siegfried (1734–1809), der seit der Gründung der Gesellschaft zu den ordentlichen Mitgliedern zählte. Von den im Katalog aufgeführten Objekten konnten in den Sammlungen des Instituts für Paläontologie mehrere Stücke nachgewiesen werden. A hand written collection catalogue in the Institute of Palaeontology of the Museum of Natural History, Berlin, whose origin was previously unclear, is identified as a catalogue of the fossil collection of the Society of the Friends of Natural History Research in Berlin (Gesellschaft Naturforschender Freunde zu Berlin), foundet in 1773. This "Index petrefactorum" from the end of the 18th century documents the extent and state of development of the collection. The author of the catalogue was Friedrich Wilhelm Siegfried (1734–1809) who was a full member of the society from the time of its founding. Among the objets listed in the catalogue it can be shown that several pieces can still be found today in the collections of the Institute of Palaeontology. doi:10.1002/mmng.20040070105

Published
2004
Full Text
View/download PDF

24. Amphibienreste aus dem Oberpliozän von Kaltensundheim (Rhön, Thüringen)

Author

G. Böhme

Subjects
Paleontology, QE701-760
Abstract

Aus den oberpliozänen Füllsedimenten eines fossilen Erdfalles bei Kaltensundheim in der Rhön (Thüringen) werden Skelettreste von anuren Amphibien beschrieben. Es liegen Reste von Bufo bufo (Linnaeus, 1758), Bufo sp., Rana temporaria Linus, 1758 sowie vermutliche Parietale nicht bestimmbarer Salientia vor. Die bisher mehrfach genannte Latonia lässt sich nicht nachweisen. Sie muss aus der Faunenliste von Kaltensundheim gestrichen werden.Skeletal remains of anuran amphibians are described from sediment filled earthfall depression of upper Pliocene age near Kaltensundheim/Rhön (Thuringia). Bufo bufo (Linnaeus, 1758), Bufo sp., Rana temporaria Linnaeus, 1758, as well as a probable parietal of an indeterminate salientian could be distinguished. There is no evidence of the often mentioned Latonia. This genus should be eliminated from the faunal list of Kaltensundheim.doi:10.1002/mmng.20020050113

Published
2002
Full Text
View/download PDF

25. The Campi Flegrei Blind Test: Evaluating the Imaging Capability of Local Earthquake Tomography in a Volcanic Area

Author

E. Priolo, L. Lovisa, A. Zollo, G. Böhm, L. D'Auria, S. Gautier, F. Gentile, P. Klin, D. Latorre, A. Michelini, T. Vanorio, and J. Virieux

Subjects
Geophysics. Cosmic physics, QC801-809
Abstract

During the 1982–1984 bradyseismic crises in the Campi Flegrei area (Italy), the University of Wisconsin deployed a network of seismological stations to record local earthquakes. In order to analyse the potential of the recorded data in terms of tomographic imaging, a blind test was recently set up and carried out in the framework of a research project. A model representing a hypothetical 3D structure of the area containing the Campi Flegrei caldera was also set up, and a synthetic dataset of time arrivals was in turn computed. The synthetic dataset consists of several thousand P- and S-time arrivals, computed at about fourteen stations. The tomographic inversion was performed by four independent teams using different methods. The teams had no knowledge of either the input velocity model or the earthquake hypocenters used to create the synthetic dataset. The results obtained by the different groups were compared and analysed in light of the true model. This work provides a thorough analysis of the earthquake tomography potential of the dataset recording the seismic activity at Campi Flegrei in the 1982–1984 period. It shows that all the tested earthquake tomography methods provide reliable low-resolution images of the background velocity field of the Campi Flegrei area, but with some differences. However, none of them succeeds in detecting the hypothetical structure details (i.e. with a size smaller than about 1.5–2 km), such as a magmatic chamber 4 km deep and especially the smaller, isolated bodies, which represent possible magmatic chimneys and intrusions.

Published
2012
Full Text
View/download PDF

28. Adaptive regridding in 3D reflection tomography

Author

A. Vesnaver, G. Rossi, and G. Böhm

Subjects
reflection tomography, irregular grids, automatic regridding, travel time inversion, Meteorology. Climatology, QC851-999, Geophysics. Cosmic physics, QC801-809
Abstract

3D reflection tomography allows the macro-model of complex geological structures to be reconstructed. In the usual approach, the spatial distribution of the velocity field is discretized by regular grids. This choice simplifies the development of the related software, but introduces two serious drawbacks: various domains of the model may be poorly covered, and a relevant mismatch between the grid and a complex velocity field may occur. So the tomographic inversion becomes unstable, unreliable and necessarily blurred. In this paper we introduce an algorithm to adapt the grid to the available ray paths and to the velocity field in sequence: so we get irregular grids with a locally variable resolution. We can guide the grid fitting procedure interactively, if we are going to introduce some geological a priori information; otherwise, we define a fully automatic approach, which exploits the Delauny triangles and Voronoi polygons.

Published
1997
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results