11 results on '"M.L. Dia"'
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2. Molecular detection of CTX-M-15-type β-lactamases in Escherichia coli strains from Senegal
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M.L. Dia, B. Ngom, R. Diagne, R. Ka, S. Lo, M.F. Cisse, G. Arlet, and A.I. Sow
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Escherichia coli ,extended-spectrum β-lactamases ,genes ,molecular characterization ,Senegal ,Infectious and parasitic diseases ,RC109-216 - Abstract
We aimed to detect the extended-spectrum β-lactamases (ESBLs) secreted by clinical strains of Escherichia coli at Fann University Hospital in Dakar and to characterize them molecularly. We identified 32 isolates producing ESBLs. The CTX-M-15 gene was the most frequently detected ESBL gene, detected in 90.63% of the isolates studied.
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- 2016
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3. Molecular detection of resistance to rifampicin and isoniazid in tuberculosis patients in Senegal
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O Balde, B Diouf, N N Cisse, P A L Gueye, M.L. Dia, M. Cisse, M Sarr, A I Sow, and F Ba
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Tuberculosis ,business.industry ,Isoniazid ,Plant Science ,respiratory system ,biochemical phenomena, metabolism, and nutrition ,bacterial infections and mycoses ,medicine.disease ,Microbiology ,Rapid detection ,Treatment failure ,03 medical and health sciences ,0302 clinical medicine ,Infectious Diseases ,030228 respiratory system ,polycyclic compounds ,medicine ,Sputum ,heterocyclic compounds ,030212 general & internal medicine ,medicine.symptom ,business ,Rifampicin ,medicine.drug - Abstract
The aim of this study was to use molecular methods to determine the profile of resistance to rifampicin (RMP or RIF) and isoniazid (INH) in mycobacteria from tuberculosis patients in Senegal. Sputum samples (48) received by the mycobacterial laboratory of the National Antituberculosis Program (NATP) in Senegal between 2012 and 2014 were studied. Most of these samples came from patients in treatment failure or relapse (58.33%). They were tested with the Xpert MTB/RIF or line-probe assays (LPAs) or both. 17 (35.41%) isolates resistant to INH, 16 (33.33%) resistant to RMP, and 16 that were multidrug-resistant (MDR) (33.33%) were identified. Two isolates (4.16%) were susceptible to INH, but resistant to RMP (INH-S/RIF-R). The molecular tests facilitated the rapid detection of MDR isolates. However, INH resistance should be assessed in all cases in which RIF resistance is detected, given the demonstrated existence of INH-S/RIF-R strains. Key words: Tuberculosis, Xpert MTB/RIF, line-probe assays (LPA), resistance, Senegal.
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- 2016
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4. Molecular characterization of group A rotaviruses circulating in Senegal over a 7-year period (2005-2011)
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Mouhamadou A. Sonko, M. Cisse, Momar Code Ba, M.L. Dia, Amadou Diop, R. Ka, D. Diop, and A I Sow
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viruses ,Period (gene) ,Strain (biology) ,virus diseases ,Plant Science ,Biology ,medicine.disease_cause ,Microbiology ,Group A ,Virology ,Diarrhea ,fluids and secretions ,Infectious Diseases ,Rotavirus ,Genotype ,medicine ,Group A rotaviruses ,medicine.symptom ,Genotyping - Abstract
Group A rotaviruses are characterized by large genomic diversity that is typically studied by genotyping of the VP7 glycoprotein, which defines G-type, and the protease-sensitive VP4, which defines P-type. The aim of this study was to examine the genotypes of group A rotavirus strains circulating in Senegal over a 7-year period between 2005 and 2011. ELISA positive stool specimens were analyzed by PAGE and were genotyped by multiplex hemi-nested RT-PCR. Data were analyzed with Epi Info 7 software. Rotavirus was found in 222 samples of stools of which 32 (14.41 %) were positive on PAGE. Five electropherotype patterns were identified, three long (L1, L2 or L3) and two short (S1 or S2). Twenty-three (23) samples had a long electropherotype and nine had a short electropherotype. One hundred strains (45.04%) were analyzed by VP7 genotyping, which identified five different genotypes: G1, G2, G3, G8 and G9. Ninety-three (93) samples (41.89%) were analyzed by VP4 genotyping which showed four different genotypes: P[4], P[6], P[8] and P[11] and mixed genotypes (1.8%). Seventy seven (34.68%) samples were genotyped for both VP7 and VP4. The G1P[8] strain was the most predominant strain followed by the G9P[8] strain. Rotavirus strains circulating in Senegal are genetically diverse. Genotypes G1P[8] and G9P[8] are the predominant strains. We also found mixed infections that could favor the emergence of new viral strains. Thus, regular monitoring of genotypes circulating in the country is required. Key words: Rotavirus, diarrhea, genotypes, children, Senegal.
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- 2015
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5. Détection fortuite de cmy-2 et dha-1 chez des isolats d’Escherichia coli producteurs de BLSE au Sénégal
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F. Robin, A. Gaye-Diallo, R. Bonnet, Racha Beyrouthy, O.F. Diallo, Ahmad Iyane Sow, Awa Ba-Diallo, M.L. Dia, Seynabou Lo, France Telecom - CNET (CNET), France Télécom, Institut Mauritanien de Recherches Océanographiques et des Pêches, Faculty of Public Health [Tripoli, Liban] (FSP III), Lebanese University [Beirut], Centre Hospitalier Universitaire Clermont Ferrand, CHU Clermont-Ferrand, Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte - Clermont Auvergne (M2iSH), Institut National de la Recherche Agronomique (INRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Clermont Auvergne (UCA)-Centre de Recherche en Nutrition Humaine d'Auvergne (CRNH d'Auvergne), Institut Mauritanien de Recherches Océanographiques et des Pêches (IMROP), Faculty of Public Health [Lebanese University] (FSP III), Lebanese University [Beirut] (LU), Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte (M2iSH), and Institut National de la Recherche Agronomique (INRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre de Recherche en Nutrition Humaine d'Auvergne (CRNH d'Auvergne)
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0301 basic medicine ,Transposable element ,biology ,030106 microbiology ,Esbl production ,[SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology ,biochemical phenomena, metabolism, and nutrition ,bacterial infections and mycoses ,biology.organism_classification ,medicine.disease_cause ,[SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology ,3. Good health ,Pathology and Forensic Medicine ,Microbiology ,03 medical and health sciences ,Plasmid ,Parasitology ,Large study ,medicine ,bacteria ,Gene ,Escherichia coli ,Bacteria ,ComputingMilieux_MISCELLANEOUS - Abstract
Cephalosporinases, which are naturally present in some enterobacterial species, can be mobilized by transposons, migrate to plasmids, and spread into other species such as Escherichia coli. The aim of this study was to characterize genes responsible for the production of extended-spectrum β-lactamases (ESBL) in E. coli isolates from urinary origin isolated in two hospitals in Senegal. Thus, a fortuitous discovery of plasmidic cephalosporinase in two isolates was noted. One of the isolates produced dha-1 associated with ESBL CTX-M-14, the other produced cmy-2, ESBL CTXM-15, tem-1 penicillinase, and oxa-1. This confirms the circulation of multidrug-resistant bacteria producing plasmidic cephalosporinase in Senegal. However, a large study is needed to better understand the prevalence and the nature of the genes involved.
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- 2017
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6. Molecular detection of CTX-M-15-type β-lactamases in Escherichia coli strains from Senegal
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Sow Ai, Ngom B, G. Arlet, Seynabou Lo, Ka R, Cisse Mf, R Diagne, and M.L. Dia
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0301 basic medicine ,030106 microbiology ,Biology ,medicine.disease_cause ,Microbiology ,lcsh:Infectious and parasitic diseases ,molecular characterization ,03 medical and health sciences ,extended-spectrum β-lactamases ,Esbl gene ,medicine ,polycyclic compounds ,Escherichia coli ,lcsh:RC109-216 ,genes ,Gene ,Letter to the Editor ,β lactamases ,biochemical phenomena, metabolism, and nutrition ,University hospital ,bacterial infections and mycoses ,Virology ,Senegal ,Infectious Diseases ,bacteria - Abstract
We aimed to detect the extended-spectrum β-lactamases (ESBLs) secreted by clinical strains of Escherichia coli at Fann University Hospital in Dakar and to characterize them molecularly. We identified 32 isolates producing ESBLs. The CTX-M-15 gene was the most frequently detected ESBL gene, detected in 90.63% of the isolates studied.
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- 2016
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7. Optimal control analysis of a COVID-19 and tuberculosis co-dynamics model
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M.S. Goudiaby, L.D. Gning, M.L. Diagne, Ben M. Dia, H. Rwezaura, and J.M. Tchuenche
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Bifurcation ,Co-infection ,COVID-19 ,Optimal control ,Reproduction number ,Tuberculosis ,Computer applications to medicine. Medical informatics ,R858-859.7 - Abstract
Tuberculosis and COVID-19 are among the diseases with major global public health concern and great socio-economic impact. Co-infection of these two diseases is inevitable due to their geographical overlap, a potential double blow as their clinical similarities could hamper strategies to mitigate their spread and transmission dynamics. To theoretically investigate the impact of control measures on their long-term dynamics, we formulate and analyze a mathematical model for the co-infection of COVID-19 and tuberculosis. Basic properties of the tuberculosis only and COVID-19 only sub-models are investigated as well as bifurcation analysis (possibility of the co-existence of the disease-free and endemic equilibria). The disease-free and endemic equilibria are globally asymptotically stable. The model is extended into an optimal control system by incorporating five control measures. These are: tuberculosis awareness campaign, prevention against COVID-19 (e.g., face mask, physical distancing), control against co-infection, tuberculosis and COVID-19 treatment. Five strategies which are combinations of the control measures are investigated. Strategy B which focuses on COVID-19 prevention, treatment and control of co-infection yields a better outcome in terms of the number of COVID-19 cases prevented at a lower percentage of the total cost of this strategy.
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- 2022
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8. HIV and COVID-19 co-infection: A mathematical model and optimal control
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N. Ringa, M.L. Diagne, H. Rwezaura, A. Omame, S.Y. Tchoumi, and J.M. Tchuenche
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COVID-19 ,HIV ,Co-infection ,Basic reproduction number ,Optimal control ,Computer applications to medicine. Medical informatics ,R858-859.7 - Abstract
A new mathematical model for COVID-19 and HIV/AIDS is considered to assess the impact of COVID-19 on HIV dynamics and vice-versa. Investigating the epidemiologic synergy between COVID-19 and HIV is important. The dynamics of the full model is driven by that of its sub-models; therefore, basic analysis of the two sub-models; HIV-only and COVID-19 only is carried out. The basic reproduction number is computed and used to prove local and global asymptotic stability of the sub-models’ disease-free and endemic equilibria. Using the fmincon function in the Optimization Toolbox of MATLAB, the model is fitted to real COVID-19 data set from South Africa. The impact of intervention measures, namely, COVID-19 and HIV prevention interventions and COVID-19 treatment are incorporated into the model using time-dependent controls. It is observed that HIV prevention measures can significantly reduce the burden of co-infections with COVID-19, while effective treatment of COVID-19 could reduce co-infections with opportunistic infections such as HIV/AIDS. In particular, the COVID-19 only prevention strategy averted about 10,500 new co-infection cases, with similar number also averted by the HIV-only prevention control.
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- 2022
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9. Topological first-order vortices in a gauged CP(2) model
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R. Casana, M.L. Dias, and E. da Hora
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Physics ,QC1-999 - Abstract
We study time-independent radially symmetric first-order solitons in a CP(2) model interacting with an Abelian gauge field whose dynamics is controlled by the usual Maxwell term. In this sense, we develop a consistent first-order framework verifying the existence of a well-defined lower bound for the corresponding energy. We saturate such a lower bound by focusing on those solutions satisfying a particular set of coupled first-order differential equations. We solve these equations numerically using appropriate boundary conditions giving rise to regular structures possessing finite-energy. We also comment the main features these configurations exhibit. Moreover, we highlight that, despite the different solutions we consider for an auxiliary function β(r) labeling the model (therefore splitting our investigation in two a priori distinct branches), all resulting scenarios engender the very same phenomenology, being physically equivalent.
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- 2017
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10. Multi-Messenger Physics With the Pierre Auger Observatory
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Karl-Heinz Kampert, Miguel Alejandro Mostafa, Enrique Zas, The Pierre Auger Collaboration, A. Aab, P. Abreu, M. Aglietta, I.F.M. Albuquerque, J.M. Albury, I. Allekotte, A. Almela, J. Alvarez Castillo, J. Alvarez-Muñiz, G.A. Anastasi, L. Anchordoqui, B. Andrada, S. Andringa, C. Aramo, H. Asorey, P. Assis, G. Avila, A.M. Badescu, A. Bakalova, A. Balaceanu, F. Barbato, R.J. Barreira Luz, S. Baur, K.H. Becker, J.A. Bellido, C. Berat, M.E. Bertaina, X. Bertou, P.L. Biermann, J. Biteau, S.G. Blaess, A. Blanco, J. Blazek, C. Bleve, M. Boháčová, D. Boncioli, C. Bonifazi, N. Borodai, A.M. Botti, J. Brack, T. Bretz, A. Bridgeman, F.L. Briechle, P. Buchholz, A. Bueno, S. Buitink, M. Buscemi, K.S. Caballero-Mora, L. Caccianiga, L. Calcagni, A. Cancio, F. Canfora, J.M. Carceller, R. Caruso, A. Castellina, F. Catalani, G. Cataldi, L. Cazon, M. Cerda, J.A. Chinellato, J. Chudoba, L. Chytka, R.W. Clay, A.C. Cobos Cerutti, R. Colalillo, A. Coleman, M.R. Coluccia, R. Conceição, A. Condorelli, G. Consolati, F. Contreras, F. Convenga, M.J. Cooper, S. Coutu, C.E. Covault, B. Daniel, S. Dasso, K. Daumiller, B.R. Dawson, J.A. Day, R.M. de Almeida, S.J. de Jong, G. De Mauro, J.R.T. de Mello Neto, I. De Mitri, J. de Oliveira, F.O. de Oliveira Salles, V. de Souza, J. Debatin, M. del Río, O. Deligny, N. Dhital, M.L. Díaz Castro, F. Diogo, C. Dobrigkeit, J.C. D'Olivo, Q. Dorosti, R.C. dos Anjos, M.T. Dova, A. Dundovic, J. Ebr, R. Engel, M. Erdmann, C.O. Escobar, A. Etchegoyen, H. Falcke, J. Farmer, G. Farrar, A.C. Fauth, N. Fazzini, F. Feldbusch, F. Fenu, L.P. Ferreyro, J.M. Figueira, A. Filipčič, M.M. Freire, T. Fujii, A. Fuster, B. García, H. Gemmeke, A. Gherghel-Lascu, P.L. Ghia, U. Giaccari, M. Giammarchi, M. Giller, D. Głas, J. Glombitza, F. Gobbi, G. Golup, M. Gómez Berisso, P.F. Gómez Vitale, J.P. Gongora, N. González, I. Goos, D. Góra, A. Gorgi, M. Gottowik, T.D. Grubb, F. Guarino, G.P. Guedes, E. Guido, R. Halliday, M.R. Hampel, P. Hansen, D. Harari, T.A. Harrison, V.M. Harvey, A. Haungs, T. Hebbeker, D. Heck, P. Heimann, G.C. Hill, C. Hojvat, E.M. Holt, P. Homola, J.R. Hörandel, P. Horvath, M. Hrabovský, T. Huege, J. Hulsman, A. Insolia, P.G. Isar, I. Jandt, J.A. Johnsen, M. Josebachuili, J. Jurysek, A. Kääpä, K.H. Kampert, B. Keilhauer, N. Kemmerich, J. Kemp, H.O. Klages, M. Kleifges, J. Kleinfeller, R. Krause, D. Kuempel, G. Kukec Mezek, A. Kuotb Awad, B.L. Lago, D. LaHurd, R.G. Lang, R. Legumina, M.A. Leigui de Oliveira, V. Lenok, A. Letessier-Selvon, I. Lhenry-Yvon, O.C. Lippmann, D. Lo Presti, L. Lopes, R. López, A. López Casado, R. Lorek, Q. Luce, A. Lucero, M. Malacari, G. Mancarella, D. Mandat, B.C. Manning, P. Mantsch, A.G. Mariazzi, I.C. Mariş, G. Marsella, D. Martello, H. Martinez, O. Martínez Bravo, M. Mastrodicasa, H.J. Mathes, S. Mathys, J. Matthews, G. Matthiae, E. Mayotte, P.O. Mazur, G. Medina-Tanco, D. Melo, A. Menshikov, K.-D. Merenda, S. Michal, M.I. Micheletti, L. Middendorf, L. Miramonti, B. Mitrica, D. Mockler, S. Mollerach, F. Montanet, C. Morello, G. Morlino, M. Mostafá, A.L. Müller, M.A. Muller, S. Müller, R. Mussa, L. Nellen, P.H. Nguyen, M. Niculescu-Oglinzanu, M. Niechciol, D. Nitz, D. Nosek, V. Novotny, L. Nožka, A Nucita, L.A. Núñez, F. Oikonomou, A. Olinto, M. Palatka, J. Pallotta, M.P. Panetta, P. Papenbreer, G. Parente, A. Parra, M. Pech, F. Pedreira, J. Pȩkala, R. Pelayo, J. Peña-Rodriguez, L.A.S. Pereira, M. Perlin, L. Perrone, C. Peters, S. Petrera, J. Phuntsok, T. Pierog, M. Pimenta, V. Pirronello, M. Platino, J. Poh, B. Pont, C. Porowski, R.R. Prado, P. Privitera, M. Prouza, A. Puyleart, S. Querchfeld, S. Quinn, R. Ramos-Pollan, J. Rautenberg, D. Ravignani, M. Reininghaus, J. Ridky, F. Riehn, M. Risse, P. Ristori, V. Rizi, W. Rodrigues de Carvalho, J. Rodriguez Rojo, M.J. Roncoroni, M. Roth, E. Roulet, A.C. Rovero, P. Ruehl, S.J. Saffi, A. Saftoiu, F. Salamida, H. Salazar, G. Salina, J.D. Sanabria Gomez, F. Sánchez, E.M. Santos, E. Santos, F. Sarazin, R. Sarmento, C. Sarmiento-Cano, R. Sato, P. Savina, M. Schauer, V. Scherini, H. Schieler, M. Schimassek, M. Schimp, F. Schlüter, D. Schmidt, O. Scholten, P. Schovánek, F.G. Schröder, S. Schröder, J. Schumacher, S.J. Sciutto, M. Scornavacche, R.C. Shellard, G. Sigl, G. Silli, O. Sima, R. Šmída, G.R. Snow, P. Sommers, J.F. Soriano, J. Souchard, R. Squartini, D. Stanca, S. Stanič, J. Stasielak, P. Stassi, M. Stolpovskiy, A. Streich, F. Suarez, M. Suárez-Durán, T. Sudholz, T. Suomijärvi, A.D. Supanitsky, J. Šupík, Z. Szadkowski, A. Taboada, O.A. Taborda, A. Tapia, C. Timmermans, C.J. Todero Peixoto, B. Tomé, G. Torralba Elipe, A. Travaini, P. Travnicek, M. Trini, M. Tueros, R. Ulrich, M. Unger, M. Urban, J.F. Valdés Galicia, I. Valiño, L. Valore, P. van Bodegom, A.M. van den Berg, A. van Vliet, E. Varela, B. Vargas Cárdenas, D. Veberič, C. Ventura, I.D. Vergara Quispe, V. Verzi, J. Vicha, L. Villaseñor, J. Vink, S. Vorobiov, H. Wahlberg, A.A. Watson, M. Weber, A. Weindl, M. Wiedeński, L. Wiencke, H. Wilczyński, T. Winchen, M. Wirtz, D. Wittkowski, B. Wundheiler, L. Yang, A. Yushkov, E. Zas, D. Zavrtanik, M. Zavrtanik, L. Zehrer, A. Zepeda, B. Zimmermann, M. Ziolkowski, Z. Zong, and F. Zuccarello
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UHECR ,high energy neutrinos ,high energy photons ,high energy neutrons ,multi-messenger astrophysics ,compact binary mergers ,Astronomy ,QB1-991 ,Geophysics. Cosmic physics ,QC801-809 - Abstract
An overview of the multi-messenger capabilities of the Pierre Auger Observatory is presented. The techniques and performance of searching for Ultra-High Energy neutrinos, photons and neutrons are described. Some of the most relevant results are reviewed, such as stringent upper bounds that were placed to a flux of diffuse cosmogenic neutrinos and photons, bounds placed on neutrinos emitted from compact binary mergers that were detected by LIGO and Virgo during their first and second observing runs, as well as searches for high energy photons and neutrons from the Galactic center that constrain the properties of the putative Galactic PeVatron, observed by the H.E.S.S. collaboration. The observation of directional correlations between ultra-high energy cosmic rays and either high energy astrophysical neutrinos or specific source populations, weighted by their electromagnetic radiation, are also discussed. They constitute additional multi-messenger approaches aimed at identifying the sources of high energy cosmic rays.
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- 2019
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11. Evidence for a mixed mass composition at the ‘ankle’ in the cosmic-ray spectrum
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A. Aab, P. Abreu, M. Aglietta, E.J. Ahn, I. Al Samarai, I.F.M. Albuquerque, I. Allekotte, P. Allison, A. Almela, J. Alvarez Castillo, J. Alvarez-Muñiz, M. Ambrosio, G.A. Anastasi, L. Anchordoqui, B. Andrada, S. Andringa, C. Aramo, F. Arqueros, N. Arsene, H. Asorey, P. Assis, J. Aublin, G. Avila, A.M. Badescu, A. Balaceanu, C. Baus, J.J. Beatty, K.H. Becker, J.A. Bellido, C. Berat, M.E. Bertaina, P.L. Biermann, P. Billoir, J. Biteau, S.G. Blaess, A. Blanco, J. Blazek, C. Bleve, M. Boháčová, D. Boncioli, C. Bonifazi, N. Borodai, A.M. Botti, J. Brack, I. Brancus, T. Bretz, A. Bridgeman, F.L. Briechle, P. Buchholz, A. Bueno, S. Buitink, M. Buscemi, K.S. Caballero-Mora, B. Caccianiga, L. Caccianiga, A. Cancio, F. Canfora, L. Caramete, R. Caruso, A. Castellina, G. Cataldi, L. Cazon, R. Cester, A.G. Chavez, A. Chiavassa, J.A. Chinellato, J. Chudoba, R.W. Clay, R. Colalillo, A. Coleman, L. Collica, M.R. Coluccia, R. Conceição, F. Contreras, M.J. Cooper, S. Coutu, C.E. Covault, J. Cronin, R. Dallier, S. D'Amico, B. Daniel, S. Dasso, K. Daumiller, B.R. Dawson, R.M. de Almeida, S.J. de Jong, G. De Mauro, J.R.T. de Mello Neto, I. De Mitri, J. de Oliveira, V. de Souza, J. Debatin, L. del Peral, O. Deligny, C. Di Giulio, A. Di Matteo, M.L. Díaz Castro, F. Diogo, C. Dobrigkeit, J.C. D'Olivo, A. Dorofeev, R.C. dos Anjos, M.T. Dova, A. Dundovic, J. Ebr, R. Engel, M. Erdmann, M. Erfani, C.O. Escobar, J. Espadanal, A. Etchegoyen, H. Falcke, K. Fang, G. Farrar, A.C. Fauth, N. Fazzini, B. Fick, J.M. Figueira, A. Filevich, A. Filipčič, O. Fratu, M.M. Freire, T. Fujii, A. Fuster, B. García, D. Garcia-Pinto, F. Gaté, H. Gemmeke, A. Gherghel-Lascu, P.L. Ghia, U. Giaccari, M. Giammarchi, M. Giller, D. Głas, C. Glaser, H. Glass, G. Golup, M. Gómez Berisso, P.F. Gómez Vitale, N. González, B. Gookin, J. Gordon, A. Gorgi, P. Gorham, P. Gouffon, A.F. Grillo, T.D. Grubb, F. Guarino, G.P. Guedes, M.R. Hampel, P. Hansen, D. Harari, T.A. Harrison, J.L. Harton, Q. Hasankiadeh, A. Haungs, T. Hebbeker, D. Heck, P. Heimann, A.E. Herve, G.C. Hill, C. Hojvat, E. Holt, P. Homola, J.R. Hörandel, P. Horvath, M. Hrabovský, T. Huege, J. Hulsman, A. Insolia, P.G. Isar, I. Jandt, S. Jansen, J.A. Johnsen, M. Josebachuili, A. Kääpä, O. Kambeitz, K.H. Kampert, P. Kasper, I. Katkov, B. Keilhauer, E. Kemp, R.M. Kieckhafer, H.O. Klages, M. Kleifges, J. Kleinfeller, R. Krause, N. Krohm, D. Kuempel, G. Kukec Mezek, N. Kunka, A. Kuotb Awad, D. LaHurd, L. Latronico, M. Lauscher, P. Lautridou, P. Lebrun, R. Legumina, M.A. Leigui de Oliveira, A. Letessier-Selvon, I. Lhenry-Yvon, K. Link, L. Lopes, R. López, A. López Casado, Q. Luce, A. Lucero, M. Malacari, M. Mallamaci, D. Mandat, P. Mantsch, A.G. Mariazzi, I.C. Mariş, G. Marsella, D. Martello, H. Martinez, O. Martínez Bravo, J.J. Masías Meza, H.J. Mathes, S. Mathys, J. Matthews, J.A.J. Matthews, G. Matthiae, E. Mayotte, P.O. Mazur, C. Medina, G. Medina-Tanco, D. Melo, A. Menshikov, S. Messina, M.I. Micheletti, L. Middendorf, I.A. Minaya, L. 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- Subjects
Physics ,QC1-999 - Abstract
We report a first measurement for ultrahigh energy cosmic rays of the correlation between the depth of shower maximum and the signal in the water Cherenkov stations of air-showers registered simultaneously by the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlation measurement is a unique feature of a hybrid air-shower observatory with sensitivity to both the electromagnetic and muonic components. It allows an accurate determination of the spread of primary masses in the cosmic-ray flux. Up till now, constraints on the spread of primary masses have been dominated by systematic uncertainties. The present correlation measurement is not affected by systematics in the measurement of the depth of shower maximum or the signal in the water Cherenkov stations. The analysis relies on general characteristics of air showers and is thus robust also with respect to uncertainties in hadronic event generators. The observed correlation in the energy range around the ‘ankle’ at lg(E/eV)=18.5–19.0 differs significantly from expectations for pure primary cosmic-ray compositions. A light composition made up of proton and helium only is equally inconsistent with observations. The data are explained well by a mixed composition including nuclei with mass A>4. Scenarios such as the proton dip model, with almost pure compositions, are thus disfavored as the sole explanation of the ultrahigh-energy cosmic-ray flux at Earth. Keywords: Pierre Auger Observatory, Cosmic rays, Mass composition, Ankle
- Published
- 2016
- Full Text
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