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66. Contemporary Presentation and Management of Valvular Heart Disease The EURObservational Research Programme Valvular Heart Disease II Survey

Author

Iung, B., Delgado, V., Rosenhek, R., Price, S., Prendergast, B., Wendler, O., Bonis, M. de, Tribouilloy, C., Evangelista, A., Bogachev-Prokophiev, A., Apor, A., Ince, H., Laroche, C., Popescu, B.A., Pierard, L., Haude, M., Hindricks, G., Ruschitzka, F., Windecker, S., Bax, J.J., Maggioni, A., Vahanian, A., Mekhaldi, S., Lemaitre, K., Authier, S., Druais, H., Goda, A., Mascherbauer, J., Samadov, F., Pasquet, A., Linhartova, K., Ihlemann, N., Abdelhamid, M., Saraste, A., Kostovska, E.S., Bajraktari, G., Mirrakhimov, E., Erglis, A., Mizariene, V., Cassar, D., Tomkiewicz-Pajak, L., Ribeiras, R., Popescu, B., Beleslin, B., Simkova, I., Dogan, S.M., Rahman-Haley, S., Shirka, E., Dado, E., Zera, E., Bica, L., Heger, M., Muslumova, F., Jahangirov, T., Ahmedov, T., Husseynov, S., Cosyns, B., Camp, G. van, Sindelarova, S., Branny, M., Parenicova, I., Vondrackova, D.J., Homza, M., Ostransky, J., Hasan-Ali, H., Abdelhady, Y., Hassan, M., Soliman, H., Mostafa, A.E., Moaaz, M., Kazamel, G., Sadek, Y., Eltobgi, S., Kamal, D., Kylmala, M., Turpeinen, A., Monin, J.L., Jobic, Y., Attias, D., Magne, J., Marechaux, S., Donal, E., Biere, L., Bernard, A., Daudin, M., Khounlaboud, M., Habib, G., Bardet, H., Audonnet, M., Thuny, F., Plurien, F., Berenfeld, A., Gervais, R., Sorbets, E., Charbonnier, A., Bauer, F., Menager-Gangloff, C., Gjerakorska-Radovikj, M., Jordanova, S., Caglayan, E., Hambrecht, R., Akin, I., Maier, L., Nickenig, G., Scholtz, W., Schulze, P.C., Heintzen, M., Er, F., Sigusch, H., Spargias, K., Kamperidis, V., Sachpekidis, V., Bellos, V., Kanakakis, I., Papafaklis, M., Makris, A., Poulimenos, L., Katsaros, A., Lampropoulos, K., Bartha, E., Zsary, A., Jebelovszki, E., Cziraki, A., Borsanyi, T., Lupkovics, G., Jarai, Z., Ibrahimi, P., Arapova, R., Laahunova, E., Sime, I., Rancane, G., Radauskaite, G., Raugaliene, R., Xuereb, R.G., Djaberi, R., Komar, M., Szymanski, P., Zaborska, B., Mizia-Stec, K., Regulski, M., Bogacki, P., Sedziwy, E., Komor, K., Myszor, J., Joao, I., Martins, R., Cabral, S., Gago, P., Cardoso, G., Almeida, I., Antunes, N., Carvalho, S., Galrinho, A., Freitas, A., Grigorica, L., Mitre, A., Ionac, A., Tint, D., Popescu, A., Petris, A.O., Onut, R., Pop, C., Usurelu, C., Beyer, R., Militaru, C., Eminovici, G., Arsenescu-Georgescu, C., Irtyuga, O., Semenova, E., Boldyrev, S., Kozmin, D., Gross, Y., Zotov, A., Kuznetsov, D., Nemchenko, E., Kulumbegov, O., Jakubov, R., Stefanov, S., Schneider, Y., Tsechanovich, V., Gamzaev, A., Fomenko, M., Mayorova, O., Skripkina, E., Safina, V., Slastin, Y., Koroleva, T., Polyaeva, L., Tarasenko, I., Alekseeva, S., Magamet, V., Medvedev, I., Khilova, L., Verevetinov, A., Stojsic-Milosavljevic, A., Nikolic, N.M., Ostric, D.K., Ruzicic, D., Pavlovic, S., Milosavljevic, J., Jovovic, L., Margoczy, R., Valocik, G., Studencan, M., Iglesias, F.C., Mendez, I., Gomez, A.G., Sanchez Fernandez, P.L., Valenzuela, G.M., Cladellas, M., Villegas, D.V., Moral, S., Gallego, I.M., Paya, R., Caballero, L., Paton, R.R., Esteban, E., Iglesia-Carreno, C., Alberca, M.T., Valle, A., Molina-Mora, M.J., Castro, N., Sayar, N., Demirtas, A.O., Yesilay, A., Demir, S., Bozkurt, A., Kanar, B., Gudul, N.E., Yildirim, T., Taylan, G., Mert, K.U., Yilmaztepe, M.A., Mert, G.O., Cosansu, K., Sayin, M.R., Karabag, T., EORP VHD II Investigators, Instituto Universitario de Investigacion de Nanocienca de Aragon, University of Zaragoza - Universidad de Zaragoza [Zaragoza], Instituto de Física de Cantabria (IFCA), Universidad de Cantabria [Santander]-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Leibniz Institute for Astrophysics Potsdam (AIP), St. Josef Hospital, Ruhr-University Bochum, Université Paris Diderot - Paris 7 (UPD7), Institut National de la Santé et de la Recherche Médicale (INSERM), Leiden University Medical Center (LUMC), Universiteit Leiden, Medizinische Universität Wien = Medical University of Vienna, Department of Imaging Royal Brompton Hospital, Royal Brompton Hospital, Guy's and St Thomas' Hospital [London], CHU Amiens-Picardie, Mécanismes physiopathologiques et conséquences des calcifications vasculaires - UR UPJV 7517 (MP3CV), Université de Picardie Jules Verne (UPJV)-CHU Amiens-Picardie, Vall d'Hebron University Hospital [Barcelona], Imagine - Institut des maladies génétiques (IMAGINE - U1163), Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM), CHU Necker - Enfants Malades [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP), Centre Hospitalier Universitaire de Liège (CHU-Liège), Lukaskrankenhaus, Universität Leipzig, University Heart Centre Freiburg - Bad Krozingen, Research Center [Associazione Nazionale Medici Cardiologi Ospedalieri] (ANMCO Research Center), Associazione Nazionale Medici Cardiologi Ospedalieri [Firenze] (ANMCO), Service de cardiologie, Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-AP-HP - Hôpital Bichat - Claude Bernard [Paris], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Université Paris Diderot - Paris 7 (UPD7), Uppsala University, SAFRAN Group, Laboratory of In Vivo Cellular and Molecular Imaging, Vrije Universiteit Brussel (VUB), Université de Lille, Sciences et Technologies, Laboratoire Traitement du Signal et de l'Image (LTSI), Université de Rennes (UR)-Institut National de la Santé et de la Recherche Médicale (INSERM), Université de Rennes - Faculté de Médecine (UR Médecine), Université de Rennes (UR), CHU Pontchaillou [Rennes], Laboratoire de Protection et Remodelage du Myocarde (PMRM), Université d'Angers (UA)-Université d'Angers (UA), Laboratoire d'Excellence : Lipoprotéines et Santé : prévention et Traitement des maladies Inflammatoires et du Cancer (LabEx LipSTIC), Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université Paris-Sud - Paris 11 (UP11)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut Gustave Roussy (IGR)-Centre Hospitalier Régional Universitaire de Nancy (CHRU Nancy)-Centre Hospitalier Régional Universitaire de Besançon (CHRU Besançon)-Université de Bourgogne (UB)-Centre Hospitalier Universitaire de Dijon - Hôpital François Mitterrand (CHU Dijon)-Centre Régional de Lutte contre le cancer Georges-François Leclerc [Dijon] (UNICANCER/CRLCC-CGFL), UNICANCER-UNICANCER-Institut National de la Santé et de la Recherche Médicale (INSERM)-Fédération Francophone de la Cancérologie Digestive, FFCD-Université de Montpellier (UM)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Etablissement français du sang [Bourgogne-Franche-Comté] (EFS BFC)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), CHU de Saint-Brieuc, Hôpital Lapeyronie [Montpellier] (CHU), Assistance Publique - Hôpitaux de Marseille (APHM), Centre Régional de Lutte contre le Cancer François Baclesse [Caen] (UNICANCER/CRLC), Normandie Université (NU)-UNICANCER-Tumorothèque de Caen Basse-Normandie (TCBN), Institut de la Vision, Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, University of Latvia (LU), Dipartimento di Scienza dei Materiali = Department of Materials Science [Milano-Bicocca], Università degli Studi di Milano-Bicocca = University of Milano-Bicocca (UNIMIB), MDM Laboratory, IMM-CNR, Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Réseaux épuration et qualité des eaux (UR REBX), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), King Abdullah University of Science and Technology (KAUST), INSTITUTO NACIONAL DE INVESTIGACAO AGRARIA E VETERINARIA VILA DO CONDE PRT, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Université de Médecine Carol Davila, Emergency Institute for Cardiovascular Diseases 'Prof. Dr. C.C. Iliescu' [Bucharest, Romania], Département Intelligence Ambiante et Systèmes Interactifs (DIASI), Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Department of photonics engineering, Danmarks Tekniske Universitet = Technical University of Denmark (DTU), Clinical sciences, Cardio-vascular diseases, Cardiology, Universität Leipzig [Leipzig], Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de la Santé et de la Recherche Médicale (INSERM), Université de Rennes 1 - Faculté de Médecine (UR1 Médecine), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Institut National de la Recherche Agronomique (INRA)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université Paris-Sud - Paris 11 (UP11)-École pratique des hautes études (EPHE), UNICANCER-UNICANCER-Institut National de la Santé et de la Recherche Médicale (INSERM)-Fédération Francophone de la Cancérologie Digestive, FFCD-Université de Montpellier (UM)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Etablissement français du sang [Bourgogne-Franche-Comté] (EFS [Bourgogne-Franche-Comté])-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Università degli Studi di Milano-Bicocca [Milano] (UNIMIB), Technical University of Denmark [Lyngby] (DTU), Université d'Angers (UA), Iung, Bernard, Delgado, Victoria, Rosenhek, Raphael, Price, Susanna, Prendergast, Bernard, Wendler, Olaf, De Bonis, Michele, Tribouilloy, Christophe, Evangelista, Arturo, Bogachev-Prokophiev, Alexander, Apor, Astrid, Ince, Hüseyin, Laroche, Cécile, Popescu, Bogdan A, Piérard, Luc, Haude, Michael, Hindricks, Gerhard, Ruschitzka, Frank, Windecker, Stephan, Bax, Jeroen J, Maggioni, Aldo, and Vahanian, Alec

Subjects
Male, Time Factors, [SDV]Life Sciences [q-bio], 030204 cardiovascular system & hematology, heart valve diseases, valvular surgery, Cardiologists, 0302 clinical medicine, Time-to-Treatment/trends, Referral and Consultation/trends, Heart Valve Diseases/diagnosis, Medicine, echocardiography, 03.02. Klinikai orvostan, 030212 general & internal medicine, Prospective Studies, Practice Patterns, Physicians', 610 Medicine & health, Referral and Consultation, valvular heart disease, Middle Aged, Europe, Practice Guidelines as Topic, cardiovascular system, Healthcare Disparities/trends, transcatheter aortic valve replacement, Female, Guideline Adherence, Presentation (obstetrics), Cardiology and Cardiovascular Medicine, guideline, Cardiologists/trends, medicine.medical_specialty, transcatheter intervention, Clinical Decision-Making, Time-to-Treatment, Europe/epidemiology, 03 medical and health sciences, Physiology (medical), Guideline Adherence/trends, Humans, Healthcare Disparities, Intensive care medicine, Aged, business.industry, medicine.disease, Practice Patterns, Physicians'/trends, Health Care Surveys, business, aged, 80 and over, guidelines as topic
Abstract

Background: Valvular heart disease (VHD) is an important cause of mortality and morbidity and has been subject to important changes in management. The VHD II survey was designed by the EURObservational Research Programme of the European Society of Cardiology to analyze actual management of VHD and to compare practice with guidelines. Methods: Patients with severe native VHD or previous valvular intervention were enrolled prospectively across 28 countries over a 3-month period in 2017. Indications for intervention were considered concordant if the intervention was performed or scheduled in symptomatic patients, corresponding to Class I recommendations specified in the 2012 European Society of Cardiology and in the 2014 American Heart Association/American College of Cardiology VHD guidelines. Results: A total of 7247 patients (4483 hospitalized, 2764 outpatients) were included in 222 centers. Median age was 71 years (interquartile range, 62–80 years); 1917 patients (26.5%) were ≥80 years; and 3416 were female (47.1%). Severe native VHD was present in 5219 patients (72.0%): aortic stenosis in 2152 (41.2% of native VHD), aortic regurgitation in 279 (5.3%), mitral stenosis in 234 (4.5%), mitral regurgitation in 1114 (21.3%; primary in 746 and secondary in 368), multiple left-sided VHD in 1297 (24.9%), and right-sided VHD in 143 (2.7%). Two thousand twenty-eight patients (28.0%) had undergone previous valvular intervention. Intervention was performed in 37.0% and scheduled in 26.8% of patients with native VHD. The decision for intervention was concordant with Class I recommendations in symptomatic patients with severe single left-sided native VHD in 79.4% (95% CI, 77.1–81.6) for aortic stenosis, 77.6% (95% CI, 69.9–84.0) for aortic regurgitation, 68.5% (95% CI, 60.8–75.4) for mitral stenosis, and 71.0% (95% CI, 66.4–75.3) for primary mitral regurgitation. Valvular interventions were performed in 2150 patients during the survey; of them, 47.8% of patients with single left-sided native VHD were in New York Heart Association class III or IV. Transcatheter procedures were performed in 38.7% of patients with aortic stenosis and 16.7% of those with mitral regurgitation. Conclusions: Despite good concordance between Class I recommendations and practice in patients with aortic VHD, the suboptimal number in mitral VHD and late referral for valvular interventions suggest the need to improve further guideline implementation.

Published
2019
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67. Disentangling the spatiotemporal structure of turbulence using multi-spacecraft data

Author

TenBarge, JM, Alexandrova, O, Boldyrev, S, Califano, F, Cerri, SS, Chen, CHK, Howes, GG, Horbury, T, Isenberg, PA, Ji, H, Klein, KG, Krafft, C, Kunz, M, Loureiro, NF, Mallet, A, Maruca, BA, Matthaeus, WH, Meyrand, R, Quataert, E, Perez, JC, Roberts, OW, Sahraoui, F, Salem, CS, Schekochihin, AA, Spence, H, Squire, J, Told, D, Verscharen, D, Wicks, RT, and Science and Technology Facilities Council (STFC)

Subjects
astro-ph.SR, physics.space-ph, physics.plasm-ph, Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics
Abstract

This white paper submitted for 2020 Decadal Assessment of Plasma Science concerns the importance of multi-spacecraft missions to address fundamental questions concerning plasma turbulence. Plasma turbulence is ubiquitous in the universe, and it is responsible for the transport of mass, momentum, and energy in such diverse systems as the solar corona and wind, accretion discs, planet formation, and laboratory fusion devices. Turbulence is an inherently multi-scale and multi-process phenomenon, coupling the largest scales of a system to sub-electron scales via a cascade of energy, while simultaneously generating reconnecting current layers, shocks, and a myriad of instabilities and waves. The solar wind is humankind's best resource for studying the naturally occurring turbulent plasmas that permeate the universe. Since launching our first major scientific spacecraft mission, Explorer 1, in 1958, we have made significant progress characterizing solar wind turbulence. Yet, due to the severe limitations imposed by single point measurements, we are unable to characterize sufficiently the spatial and temporal properties of the solar wind, leaving many fundamental questions about plasma turbulence unanswered. Therefore, the time has now come wherein making significant additional progress to determine the dynamical nature of solar wind turbulence requires multi-spacecraft missions spanning a wide range of scales simultaneously. A dedicated multi-spacecraft mission concurrently covering a wide range of scales in the solar wind would not only allow us to directly determine the spatial and temporal structure of plasma turbulence, but it would also mitigate the limitations that current multi-spacecraft missions face, such as non-ideal orbits for observing solar wind turbulence. Some of the fundamentally important questions that can only be addressed by in situ multipoint measurements are discussed.

Published
2019

68. Extreme Plasma Astrophysics

Author

Uzdensky, D, Begelman, M, Beloborodov, A, Blandford, R, Boldyrev, S, Cerutti, B, Fiuza, F, Giannios, D, Grismayer, T, Kunz, M, Loureiro, N, Lyutikov, M, Medvedev, M, Petropoulou, M, Philippov, A, Quataert, E, Schekochihin, A, Schoeffler, K, Silva, L, Sironi, L, Spitkovsky, A, Werner, G, Zhdankin, V, Zrake, J, and Zweibel, E

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Plasma Physics (physics.plasm-ph), Physics::Plasma Physics, Physics::Space Physics, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astrophysics - High Energy Astrophysical Phenomena, Physics - Plasma Physics
Abstract

This is a science white paper submitted to the Astro-2020 and Plasma-2020 Decadal Surveys. The paper describes the present status and emerging opportunities in Extreme Plasma Astrophysics -- a study of astrophysically-relevant plasma processes taking place under extreme conditions that necessitate taking into account relativistic, radiation, and QED effects., A science white paper submitted to the Astro-2020 and Plasma-2020 Decadal Surveys. 7 pages including cover page and references. Paper updated in late March 2019 to include a several additional co-authors and references, and a few small changes

Published
2019

80. Current trends in cannulation and neuroprotection during surgery of the aortic arch in Europe†‡

Author

De Paulis, Ruggero, Czerny, Martin, Weltert, Luca, Bavaria, Joseph, Borger, Michael A., Carrel, Thierry P., Etz, Christain D., Grimm, Michael, Loubani, Mahmoud, Pacini, Davide, Resch, Timothy, Urbanski, Paul P., Weigang, Ernst, Grimm, M., Grabenwöger, M., Schepens, M., Maatouk, M., Van Ruyssevelt, P., Rodrigus, I., Van Nooten, G., Panayotov, P., Papantchev, V., Medved, I., Sutlic, Z., Ilkjaer, L., Skov Olsen, P., Hippelainen, M., Deleuze, P., Collart, F., Camilleri, L., Caus, T., Villemot, JP, Schmoeckel, M., Iversen, S., Matschke, K., Moritz, A., Fischlein, T., Hammel, D., Doll, KN, Warnecke, H., Reichenspurner, H., Beyesdorf, F., Boning, A., Liebold, A., Asfour, B., Mohr, W., Diegeler, A., Charitos, C., Khouri, M., Palatianos, G., Bairaktaris, A., Sivitanidis, E., Gregorini, R., Torracca, L., Cirio, EM, Mercogliano, D., Esposito, G., Cassese, M., Caparrotti, S., Mazzei, V., De Paulis, R., Mazzola, A., Menicanti, L., Tarelli, G., Glauber, M., Murzi, B., Antona, C., Casabona, R., Di Bartolomeo, R., Muneretto, C., Gherli, T., Lamarra, M., Stradiņš, P., Klautz, R., Grandjean, JG, Stooker, W., Bogers, JJ, Geiran, O., Hirnle, T., Rogowski, J., Brykczynski, M., Jemielity, M., Antunes, M., Tinica, G., Gaspar, M., Priktov, V., Maksimov, A., Belash, S., Boldyrev, S., Barbuchatti, K., Nikolishin, A., Abdulaev, M., Izhbuldin, R., Yunusov, V., Bikbulatov, R., Dzemeshkevich, S., Podoksenov, A., Shipulin, V., Zotov, A., Lockowandt, U., Castellanos, E., Sádaba, R., Mosquera Rodriguez, V., Silva, J., Nistal, JF, Galiñanes Hernández, M., Porras, C., Llorens, R., Saenz Berbejillo, A., Prêtre, R., Carrel, T., Senay, S., Orhan Veli, D., Ruçhan, A., Bülent, K., Sener, E., Katrancioglu, N., Apaydin, AZ, Battaloğlu, B., Yilik, L., Özeren, M., Aykut Aka, S., Tuygun, AK, Ketenci, B., Dağsali, S., Kaplan, M., Akçevin, A., and Nashef, S.

Abstract

OBJECTIVES To conduct a survey across European cardiac centres to evaluate the methods used for cerebral protection during aortic surgery involving the aortic arch. METHODS All European centres were contacted and surgeons were requested to fill out a short, comprehensive questionnaire on an internet-based platform. One-third of more than 400 contacted centres completed the survey correctly. RESULTS The most preferred site for arterial cannulation is the subclavian-axillary, both in acute and chronic presentation. The femoral artery is still frequently used in the acute condition, while the ascending aorta is a frequent second choice in the case of chronic presentation. Bilateral antegrade brain perfusion is chosen by the majority of centres (2/3 of cases), while retrograde perfusion or circulatory arrest is very seldom used and almost exclusively in acute clinical presentation. The same pumping system of the cardio pulmonary bypass is most of the time used for selective cerebral perfusion, and the perfusate temperature is usually maintained between 22 and 26°C. One-third of the centres use lower temperatures. Perfusate flow and pressure are fairly consistent among centres in the range of 10-15 ml/kg and 60 mmHg, respectively. In 60% of cases, barbiturates are added for cerebral protection, while visceral perfusion still receives little attention. Regarding cerebral monitoring, there is a general tendency to use near-infrared spectroscopy associated with bilateral radial pressure measurement. CONCLUSIONS These data represent a snapshot of the strategies used for cerebral protection during major aortic surgery in current practice, and may serve as a reference for standardization and refinement of different approaches

Published
2017

81. Nature of kinetic scale turbulence in the Earth's magnetosheath

Author

Chen, CHK, Boldyrev, S, and Science and Technology Facilities Council (STFC)

Subjects
Science & Technology, 0306 Physical Chemistry (Incl. Structural), turbulence, MAGNETIC-FIELD FLUCTUATIONS, ANISOTROPY MEASUREMENTS, Astronomy & Astrophysics, magnetic fields, plasmas, 0305 Organic Chemistry, SOLAR-WIND TURBULENCE, 0201 Astronomical And Space Sciences, solar wind, ELECTRON MAGNETOHYDRODYNAMIC TURBULENCE, Physics::Space Physics, Physical Sciences, COLLISIONLESS SHOCKS, waves, ALFVENIC TURBULENCE, CLUSTER OBSERVATIONS, TAYLOR HYPOTHESIS, DISSIPATION RANGE, ASTROPHYSICAL GYROKINETICS
Abstract

We present a combined observational and theoretical analysis to investigate the nature of plasma turbulence at kinetic scales in the Earth's magnetosheath. In the first decade of the kinetic range, just below the ion gyroscale, the turbulence was found to be similar to that in the upstream solar wind: predominantly anisotropic, low-frequency and kinetic Alfvén in nature. A key difference, however, is that the magnetosheath ions are typically much hotter than the electrons, ${T}_{{\rm{i}}}\gg {T}_{{\rm{e}}}$, which, together with ${\beta }_{{\rm{i}}}\sim 1$, leads to a change in behavior in the second decade, close to electron scales. The turbulence here is characterized by an increased magnetic compressibility, following a mode we term the inertial kinetic Alfvén wave, and a steeper spectrum of magnetic fluctuations, consistent with the prediction ${E}_{B}({k}_{\perp })\propto {k}_{\perp }^{-11/3}$ that we obtain from a set of nonlinear equations. This regime of plasma turbulence may also be relevant for other astrophysical environments with ${T}_{{\rm{i}}}\gg {T}_{{\rm{e}}}$, such as the solar corona, hot accretion flows, and regions downstream of collisionless shocks.

Published
2017

82. Research of the Influence of Several Constants of the Quadratic Turbulence Model on the Results of Pulsated Separated Flow Simulation

Author

Boldyrev A., Boldyrev S., and Kharchuk S.

Subjects
Physics::Fluid Dynamics, turbulent flow, numerical simulation, pulsated flow, reattachment length, separated flow, turbulence model
Abstract

© 2017 The Authors.Offered in this article modification variant of quadratic High-Reynolds number k-ϵ turbulence model is intended for more accurate prediction of the local characteristics of pulsated separated turbulent flow of compressible gas in channel behind diaphragm at rather high values of Strouhal number. Correction functions C1 and κ values are determined at Sh = 0.0.5, Re = 17000 and Re = 33000 regimes. Thus, the mathematical model of the flow is represented by the Reynolds-averaged Navier-Stokes equations, continuity equation, energy equation, equation of the ideal gas, equations of the original and modified turbulence model. The dimensions of the computational region, regime parameters and experimental data of the flow characteristics are taken from the dissertation of I.A. Davletshin. Generation of the pulsation in numerical experiments is achieved by periodic fluctuation of the outlet area in the channel during the time. Verifying calculations were carried out. Simulation results (skin-friction and pressure coefficients, reattachment length, turbulent characteristics) were compared with experimental data. Shear stress and axial velocity varying along the channel during the pulsation period was analyzed. It was established that original turbulence model permits necessary calculation accuracy only at Sh < 0.07, moreover, applying of the correction function allows to predict behavior of observed flow parameters at a higher pulsation frequency.

Published
2017

87. Development of a mathematical model of hydroerosive wear in piston couples of hydraulic machines: Part 2

Author

Budarova O. and Boldyrev S.

Subjects
hydroerosive wear, air, math model, piston couples, water, fluids, hydraulic machines
Abstract

© 2014, Allerton Press, Inc. The paper presents a definition of hydroerosive wear that occurs in hydraulic machines due to the presence of water or air in a fluid that was used in the mathematical model. As is indicated by the complex of equations obtained by conversions, the relationship between the velocity of the hydroerosive wear of piston couples and the presence of water in fluid is exponential. In addition, the wear velocity is determined to be directly proportional to the presence of air inside of the hydraulic system and inversely proportional to the pressure achieved by the pump.

Published
2014

88. Numerical experiment optimization to obtain the characteristics of the centrifugal pump steps package

Author

Boldyrev S. and Boldyrev A.

Abstract

© Published under licence by IOP Publishing Ltd. The numerical simulation method of turbulent flow in a running space of the working-stage in a centrifugal pump using the periodicity conditions has been formulated. The proposed method allows calculating the characteristic indices of one pump step at a lower computing resources cost. The comparison of the pump characteristics' calculation results with pilot data has been conducted.

Published
2014

89. Development of a mathematical model of the hydroerosive wear of the piston couple in hydraulic machines: Part 1

Author

Budarova O. and Boldyrev S.

Subjects
hydroerosive wear, air, math model, water, piston couple, fluids, hydraulic machines
Abstract

© 2014, Allerton Press, Inc. The paper presents a definition of hydroerosive wear, which occurs in hydraulic machines due to water/air presence in fluid, obtained from a mathematical model. The model includes fatigue processes related to the influence of hydraulic water droplets inside of air bubbles in the surface layer of metal, as well as a sharp increase in temperature caused by adiabatic compression in the piston chamber of a hydraulic machine.

Published
2014

99. Avifauna Structure Of Boreal Zone Open Habitats (Ishim Plain, Western Siberia)

Author

Boldyrev Stepan, Levykh Alena, Ganzherli Nadezhda, Gashev Sergey, and Sorokina Natalya

Subjects
avifauna, ornithocenosis, ishim river region, open habitats, species diversity, natural-climatic zones, Ecology, QH540-549.5
Abstract

In 2014‒2016 field seasons, bird censuses were conducted on 34 flyways in seven different types of open habitats of the Russian part of the Ishim River region. Ninety-five species from 72 genera from 10 orders were registered. It is established that the taxonomic composition and ecological structure of avifauna of the habitats under investigation comply with their biotopical characteristics; diversity of taxons and ecological groups show positive correlation with habitats’ heterogeneity. In natural habitats, the maximum total abundance of birds, highest species diversity within the habitat (α-diversity) and species sustainability are characteristic of river meadows ornithocenoses, mainly due to low-numbered species and a higher evenness index. In disturbed habitats, the maximum total abundance, species diversity, Shannon diversity index, Pielou’s evenness index, minimal index of diversity and highest indices of elastic and general sustainability are characteristic of abandoned fields ornithocenoses, due to a more complex structure of vegetation communities and habitat resource capacity, which increased in the course of secondary succession. Due to natural and historical unity, middle and northern forest steppe’s avifaunae are most similar. The southern taiga open habitats’ ornithocenoses are most heterogeneous, due to an increased amount of dendrophilous birds along with forest habitats’ increased area and diversity.

Published
2021
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100. Residual Energy in Weak and Strong MHD Turbulence

Author

Boldyrev, S., Perez, J. C., and Yuxuan Wang

Subjects
Physics::Fluid Dynamics, Plasma Physics (physics.plasm-ph), Astrophysics of Galaxies (astro-ph.GA), Physics::Space Physics, Fluid Dynamics (physics.flu-dyn), FOS: Physical sciences, Physics - Fluid Dynamics, Chaotic Dynamics (nlin.CD), Nonlinear Sciences - Chaotic Dynamics, Astrophysics - Astrophysics of Galaxies, Physics - Plasma Physics
Abstract

Recent numerical and observational studies revealed that spectra of magnetic and velocity fluctuations in MHD turbulence have different scaling indexes. This intriguing feature has been recently explained in the case of weak MHD turbulence, that is, turbulence consisting of weakly interacting Alfven waves. However, astrophysical turbulence is strong in majority of cases. In the present work, we propose a unifying picture that allows one to address weak and strong MHD turbulence on the same footing. We argue that magnetic and kinetic energies are different in both weak and strong MHD turbulence. Their difference, the so-called residual energy, is spontaneously generated by turbulence, it has the Fourier spectrum E_r(k)=E_v(k)-E_b(k) \propto -f_w(k_||/k_perp) k_perp^{-2} in weak turbulence, and E_r(k) \propto -f_s(k_||/k_perp) k_perp^{-3} in strong turbulence. Here f_w,s(x) are functions declining fast for x>C_w,s and not significantly varying for $x, Comment: To appear in ASP Conference Series, 6th International Conference of Numerical Modeling of Space Plasma Flows (2011), Nikolai V. Pogorelov, Ed

Published
2012
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