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IEEE International Conference on Bioinformatics and Biomedicine

作者： Reda Rawi Khalid Kunji Abdelali Haoudi Halima Bensmail Computational Science and Engineering Qatar Computing Research Institute Hamad Bin Khalifa University King Abdullah International Medical Research Center King Abdulaziz Medical City

ISBN: (纸本)9781467368001

HIV-1 Env glycoprotein complex is the key protein that mediates binding and entry of HIV-1 into human host cells. The complex entry process involves three main steps. First, the attachment, the interaction of gp120 and CD4. Second, the coreceptor binding, where gp120 binds the chemokine receptor CCR5 or CXCR4, and finally, the fusion of viral and host cell membranes. Despite the fact that several coordinate structures of HIV-1 Env in unliganded state exist (as well as in complex with CD4, CD4 mimics, or various antibodies, and of gp41 in intermediate and post-fusion state), a comprehensive understanding of structural arrangements and communication within gp120 and gp41 domains during the entry is far from complete. In this study, we applied a direct amino acid interaction detecting method to analyse the function and structure of HIV-1 Env protein sequences representing all group M subtypes. We identified more than 400 coevolving residue pairs within Env, of which the majority are real contacts and proximal in the available coordinate structures, or have functional implications such as receptor binding, variable loop, gp120-gp41, and interdomain interactions. This work provides a new dimension of information in HIV research, important in assisting protein coordinate structure prediction and in designing new and effective entry inhibitors.

关键词： HIV-1 Env Group M subtypes Contact Prediction

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Latest Advances in Theories and Applications of Cognitive Robotics and Brain-Inspired Systems

Latest Advances in Theories and Applications of Cognitive Ro...

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2015 IEEE Advanced Information Technology,Electronic and Automation Control Conference(IAEAC 2015)

作者： YingXU Wang International Institute of Cognitive Informatics and Cognitive Computing(ICIC) Laboratory for Computational Intelligence Cognitive Systemsand Software Science Dept.of Electrical and Computer Engineering Schulich School of Engineering and Hotchkiss Brain Institute University of Calgary

In the new era of intelligence revolution beyond information and computing revolutions,a brain-like intelligent system is emerging known as cognitive robots.A cognitive robot is an autonomous system that is capable of perception,learning,and inference mimicking the cognitive mechanisms of the brain by computational *** robotics is a discipline that studies theories,mathematical means,implementations,and engineering applications of cognitive *** theoretical foundations of cognitive robotics are underpinned in brain science,cognitive science,abstract intelligence,knowledge science,intelligence science,cognitive linguistics,and denotational *** keynote lecture presents the latest advances in theories and applications of cognitive robotics and brain-inspired *** theoretical framework of cognitive robotics and its denotational mathematical means such as concept algebra,semantic algebra,behavioral process algebra,and inference algebra are *** challenges in cognitive robotics are formally studied on what the necessary and sufficient intelligent behaviors of cognitive robots are,and what distinguish the intelligent capabilities of cognitive robots from their imperative *** structural and functional models of cognitive robots are explored at the intelligent layers of imperative,autonomic,and cognitive *** progress in cognitive robotics has led to the development of cognitive systems,nextgeneration computers,and cognitive machine learning engines,as well as the growth of contemporary knowledge-based industries.

关键词： Cognitive robotics cognitive informatics cognitive computing abstract intelligence computational intelligence denotational mathematics concept algebra semantic algebra brain science neuroinformatics cognitive machine learning cognitive knowledge base artificial intelligence and cognitive systems

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Packet-oriented streamline tracing on modern SIMD architectures

Packet-oriented streamline tracing on modern SIMD architectu...

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15th Eurographics Symposium on Parallel Graphics and Visualization, EG PGV 2015

作者： Hentschel, B. Göbbert, J.H. Klemm, M. Springer, P. Schnorr, A. Kuhlen, T.W. Virtual Reality Group RWTH Aachen University Germany JARA - High Performance Computing Germany Software and Services Group Intel GmbH Germany Aachen Institute for Advanced Study in Computational Engineering Science RWTH Aachen University Germany Jülich Supercomputing Centre Forschungszentrum Jülich GmbH Germany HPAC - High Performance and Automatic Computing RWTH Aachen University Germany

ISBN: (纸本)9783905674811

The advection of integral lines is an important computational kernel in vector field visualization. We investigate how this kernel can profit from vector (SIMD) extensions in modern CPUs. As a baseline, we formulate a streamline tracing algorithm that facilitates auto-vectorization by an optimizing compiler. We analyze this algorithm and propose two different optimizations. Our results show that particle tracing does not per se benefit from SIMD computation. Based on a careful analysis of the auto-vectorized code, we propose an optimized data access routine and a re-packing scheme which increases average SIMD efficiency. We evaluate our approach on three different, turbulent flow fields. Our optimized approaches increase integration performance up to 5:6 over our baseline measurement. We conclude with a discussion of current limitations and aspects for future work. © The Eurographics Association 2015.

关键词： Program processors

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Cosmology with phase 1 of the square kilometre array

arXiv

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arXiv 2018年

作者： Bacon, David J. Battye, Richard A. Bull, Philip Camera, Stefano Ferreira, Pedro G. Harrison, Ian Parkinson, David Pourtsidou, Alkistis Santos, Mário G. Wolz, Laura Abdalla, Filipe Akrami, Yashar Alonso, David Andrianomena, Sambatra Ballardini, Mario Bernal, José Luis Bertacca, Daniele Bengaly, Carlos A.P. Bonaldi, Anna Bonvin, Camille Brown, Michael L. Chapman, Emma Chen, Song Chen, Xuelei Cunnington, Steven Davis, Tamara M. Dickinson, Clive Fonseca, José Grainge, Keith Harper, Stuart Jarvis, Matt J. Maartens, Roy Maddox, Natasha Padmanabhan, Hamsa Pritchard, Jonathan R. Raccanelli, Alvise Rivi, Marzia Roychowdhury, Sambit Sahlén, Martin Schwarz, Dominik J. Siewert, Thilo M. Viel, Matteo Villaescusa-Navarro, Francisco Xu, Yidong Yamauchi, Daisuke Zuntz, Joe Institute of Cosmology & Gravitation University of Portsmouth Dennis Sciama Building PortsmouthPO1 3FX United Kingdom Jodrell Bank Centre for Astrophysics School of Physics and Astronomy University of Manchester ManchesterM13 9PL United Kingdom School of Physics & Astronomy Queen Mary University of London 327 Mile End Road LondonE1 4NS United Kingdom Dipartimento di Fisica Universitá degli Studi di Torino Via P. Giuria 1 Torino10125 Italy INFN – Istituto Nazionale di Fisica Nucleare Sezione di Torino Via P. Giuria 1 Torino10125 Italy INAF – Osservatorio Astrofisico di Torino Strada Osservatorio 20 Pino Torinese10025 Italy Department of Physics University of Oxford Denys Wilkinson Building Keble Road OxfordOX1 3RH United Kingdom Korea Astronomy and Space Science Institute Yuseong-gu Daedeokdae-ro 776 Daejeon34055 Korea Republic of Department of Physics & Astronomy University of the Western Cape Cape Town7535 South Africa SKA South Africa The Park Cape Town7405 South Africa Instituto de Astrofisica e Ciencias do Espaco Universidade de Lisboa OAL Tapada da Ajuda LisboaPT1349-018 Portugal Astrophysics Group School of Physics University of Melbourne ParkvilleVIC3010 Australia Department of Physics and Astronomy University College London Gower Street LondonWC1E 6BT United Kingdom Department of Physics and Electronics Rhodes University PO Box 94 Grahamstown6140 South Africa Lorentz Institute for Theoretical Physics Leiden University P.O. Box 9506 Leiden2300 RA Netherlands Département de Physique École Normale Supérieure PSL Research University CNRS 24 rue Lhomond Paris75005 France Department of Mathematics & Applied Mathematics University of Cape Town Cape Town7701 South Africa INAF - Istituto di Radioastronomia via Gobetti 101 Bologna40129 Italy Martí Franquès 1 BarcelonaE08028 Spain Dept. de Física Quàntica i Astrofísica Universitat de Barcelona Martí i Franquès 1 BarcelonaE08028 Spain Argelander-Institut für Astronomi

We present a detailed overview of the cosmological surveys that will be carried out with Phase 1 of the Square Kilometre Array (SKA1), and the science that they will enable. We highlight three main surveys: a medium-deep continuum weak lensing and low-redshift spectroscopic HI galaxy survey over 5,000 deg2;a wide and deep continuum galaxy and HI intensity mapping survey over 20,000 deg2 from z = 0.35 − 3;and a deep, high-redshift HI intensity mapping survey over 100 deg2 from z = 3 − 6. Taken together, these surveys will achieve an array of important scientific goals: measuring the equation of state of dark energy out to z ∼ 3 with percent-level precision measurements of the cosmic expansion rate;constraining possible deviations from General Relativity on cosmological scales by measuring the growth rate of structure through multiple independent methods;mapping the structure of the Universe on the largest accessible scales, thus constraining fundamental properties such as isotropy, homogeneity, and non-Gaussianity;and measuring the HI density and bias out to z = 6. These surveys will also provide highly complementary clustering and weak lensing measurements that have independent systematic uncertainties to those of optical surveys like LSST and Euclid, leading to a multitude of synergies that can improve constraints significantly beyond what optical or radio surveys can achieve on their own. This document, the 2018 Red Book, provides reference technical specifications, cosmological parameter forecasts, and an overview of relevant systematic effects for the three key surveys, and will be regularly updated by the Cosmology science Working Group in the run up to start of operations and the Key science Programme of SKA1. Copyright © 2018, The Authors. All rights reserved.

关键词： Surveys

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A stochastic maximum principle for risk-sensitive mean-field type control

A stochastic maximum principle for risk-sensitive mean-field...

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作者： Djehiche, Boualem Tembine, Hamidou Tempone, Raul Department of Mathematics KTH Royal Institute of Technology Stockholm100 44 Sweden Center for Interdisciplinary Studies in Security and Privacy Electrical and Computer Engineering Polytechnic School of Engineering New York University NY10003 United States Division of Engineering Saadiyat Island New York University Abu Dhabi Abu Dhabi United Arab Emirates SRI Uncertainty Quantification Center in Computational Science and Engineering CEMSE King Abdullah University of Science and Technology Thuwai Jeddah23955-6900 Saudi Arabia

In this paper we study mean-field type control problems with risk-sensitive performance functionals. We establish a stochastic maximum principle (SMP) for optimal control of stochastic differential equations (SDEs) of mean-field type, in which the drift and the diffusion coefficients as well as the performance functional depend not only on the state and the control but also on the mean of the distribution of the state. Our result extends the risk-sensitive SMP (without mean-field coupling) of Lim and Zhou (2005), derived for feedback (or Markov) type optimal controls, to optimal control problems for non-Markovian dynamics which may be time-inconsistent in the sense that the Bellman optimality principle does not hold. In our approach to the risk-sensitive SMP, the smoothness assumption on the value-function imposed in Lim and Zhou (2005) needs not be satisfied. For a general action space a Peng's type SMP is derived, specifying the necessary conditions for optimality. Two examples are carried out to illustrate the proposed risk-sensitive mean-field type SMP under linear stochastic dynamics with exponential quadratic cost function. Explicit solutions are given for both mean-field free and mean-field models. © 1963-2012 IEEE.

关键词： Maximum principle

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Analysis of Sparse Quasi-Newton Updates with Positive Definite Matrix Completion

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Journal of the Operations Research Society of China 2014年第1期2卷 39-56页

作者： Yu-Hong Dai Nobuo Yamashita State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics and Scientific/Engineering ComputingAcademy of Mathematics and Systems ScienceChinese Academy of SciencesP.O.Box 2719Beijing 100080People’s Republic of China Department of Applied Mathematics and Physics Graduate School of InformaticsKyoto UniversityKyoto 606-8501Japan

Based on the idea of maximum determinant positive definite matrix completion,Yamashita(Math Prog 115(1):1–30,2008)proposed a new sparse quasi-Newton update,called MCQN,for unconstrained optimization problems with sparse Hessian *** exchange of the relaxation of the secant equation,the MCQN update avoids solving difficult subproblems and overcomes the ill-conditioning of approximate Hessian ***,local and superlinear convergence results were only established for the MCQN update with the DFP *** this paper,we extend the convergence result to the MCQN update with the whole Broyden’s convex *** results are also reported,which suggest some efficient ways of choosing the parameter in the MCQN update the Broyden’s family.

关键词： Quasi-Newton method Large-scale problems Sparsity Positive definite matrix completion Superlinear convergence

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Dependence of atmospheric muon rate on seawater depth measured with the first KM3NeT detection units

arXiv

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arXiv 2019年

作者： Ageron, M. Aiello, S. Ameli, F. Andre, M. Androulakis, G. Anghinolfi, M. Anton, G. Ardid, M. Aublin, J. Bagatelas, C. Barbarino, G. Baret, B. Basegmez du, S. Pree Belias, A. Berbee, E. van Den, A.M. Berg Bertin, V. van Beveren, V. Biagi, S. Biagioni, A. Bianucci, S. Billault, M. Bissinger, M. de Boer, R. Boumaaza, J. Bourret, S. Bouta, M. Bouwhuis, M. Bozza, C. Brânzaş, H. Briel, M. Bruchner, M. Bruijn, R. Brunner, J. Buis, E. Buompane, R. Busto, J. Cacopardo, G. Caillat, L. Calì, C. Calvo, D. Capone, A. Celli, S. Chabab, M. Chau, N. Cherubini, S. Chiarella, V. Chiarusi, T. Circella, M. Cocimano, R. Coelho, J.A.B. Coleiro, A. Colomer, M. Molla Colonges, S. Coniglione, R. Cosquer, A. Coyle, P. Creusot, A. Cuttone, G. D’Amato, C. D’Amico, A. D’Onofrio, A. Dallier, R. de Palma, M. de Sio, C. Di Palma, I. Díaz, A.F. Diego-Tortosa, D. Distefano, C. Domi, A. Donà, R. Donzaud, C. van Dooren, L. Dornic, D. Dörr, M. Durocher, M. Eberl, T. van Eeden, T. El Bojaddaini, I. Eljarrari, H. Elsaesser, D. Enzenhöfer, A. Fermani, P. Ferrara, G. Filipović, M.D. Fusco, L.A. Gajanana, D. Gal, T. Garcia Soto, A. Garufi, F. Gialanella, L. Giorgio, E. Giuliante, A. Gozzini, S.R. Gracia, R. Graf, K. Grasso, D. Grégoire, T. Grella, G. Grimaldi, A. Grmek, A. Guderian, D. Guerzoni, M. Guidi, C. Hallmann, S. Hamdaoui, H. van Haren, H. Heijboer, A. Hekalo, A. Henry, S. Hernández-Rey, J.J. Hofestädt, J. Huang, F. Huesca, E. Santiago Illuminati, G. James, C.W. Jansweijer, P. Jongen, M. de Jong, M. de Jong, P. Kadler, M. Kalaczynski, P. Kalekin, O. Katz, U.F. Kayzel, F. Keller, P. Khan, N.R. Chowdhury van der Knaap, F. Koffeman, E.N. Kooijman, P. Koopstra, J. Kouchner, A. Kreter, M. Kulikovskiy, V. Meghna, K.K. Lahmann, R. Lamare, P. Larosa, G. Laurence, J. Le Breton, R. Leone, F. Leonora, E. Levi, G. Librizzi, F. Lincetto, M. Litrico, P. Llorens, C.D. Alvarez Lonardo, A. Longhitano, F. Lopez-Coto, D. Maggi, G. Manczak, J. Mannheim, K. Aix Marseille Univ CNRS/IN2P3 CPPM Marseille France INFN Sezione di Catania Via Santa Sofia 64 Catania95123 Italy INFN Sezione di Roma Piazzale Aldo Moro 2 Roma00185 Italy Universitat Politècnica de Catalunya Laboratori d’Aplicacions Bioacústiques Centre Tecnològic de Vilanova i la Geltrú Avda. Rambla Exposició s/n Vilanova i la Geltrú08800 Spain NCSR Demokritos Institute of Nuclear and Particle Physics Ag. Paraskevi Attikis Athens15310 Greece INFN Sezione di Genova Via Dodecaneso 33 Genova16146 Italy Friedrich-Alexander-Universität Erlangen-Nürnberg Erlangen Centre for Astroparticle Physics Erwin-Rommel-Straße 1 Erlangen91058 Germany Universitat Politècnica de València Instituto de Investigación para la Gestión Integrada de las Zonas Costeras C/ Paranimf 1 Gandia46730 Spain APC Université Paris Diderot CNRS/IN2P3 CEA/IRFU Observatoire de Paris Sorbonne Paris Cité Paris75205 France INFN Sezione di Napoli Complesso Universitario di Monte S. Angelo Via Cintia ed. G Napoli80126 Italy Università di Napoli "Federico II" Dip. Scienze Fisiche "E. Pancini" Complesso Universitario di Monte S. Angelo Via Cintia ed. G Napoli80126 Italy Nikhef National Institute for Subatomic Physics PO Box 41882 Amsterdam1009 DB Netherlands KVI-CART University of Groningen Groningen Netherlands INFN Laboratori Nazionali del Sud Via S. Sofia 62 Catania95123 Italy INFN Sezione di Pisa Largo Bruno Pontecorvo 3 Pisa56127 Italy University Mohammed V in Rabat Faculty of Sciences 4 av. Ibn Battouta B.P. 1014 RabatR.P. 10000 Morocco University Mohammed I Faculty of Sciences BV Mohammed VI B.P. 717 R.P Oujda60000 Morocco Università di Salerno e INFN Gruppo Collegato di Salerno Dipartimento di Fisica Via Giovanni Paolo II 132 Fisciano84084 Italy ISS Atomistilor 409 MagureleRO-077125 Romania University of Amsterdam Institute of Physics/IHEF PO Box 94216 Amsterdam1090 GE Netherlands TNO Technical Sciences PO Box 155 Delft2600 AD Netherlands Un

KM3NeT is a research infrastructure located in the Mediterranean Sea, that will consist of two deep-sea Cherenkov neutrino detectors. With one detector (ARCA), the KM3NeT Collaboration aims at identifying and studying TeV-PeV astrophysical neutrino sources. With the other detector (ORCA), the neutrino mass ordering will be determined by studying GeV-scale atmospheric neutrino oscillations. The first KM3NeT detection units were deployed at the Italian and French sites between 2015 and 2017. In this paper, a description of the detector is presented, together with a summary of the procedures used to calibrate the detector in-situ. Finally, the dependence of muon rate between 2232−3386 m seawater depth is compared with a parameterisation of the underwater muon flux. Copyright © 2019, The Authors. All rights reserved.

关键词： Neutrons

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Tomography is Necessary for Universal Entanglement Detection with Single-Copy Observables

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Physical Review Letters 2016年第23期116卷 230501-230501页

作者： Dawei Lu Tao Xin Nengkun Yu Zhengfeng Ji Jianxin Chen Guilu Long Jonathan Baugh Xinhua Peng Bei Zeng Raymond Laflamme Institute for Quantum Computing University of Waterloo Waterloo N2L 3G1 Ontario Canada State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics Tsinghua University Beijing 100084 China Centre for Quantum Computation and Intelligent Systems Faculty of Engineering and Information Technology University of Technology Sydney NSW 2007 Australia Department of Mathematics and Statistics University of Guelph Guelph Ontario N1G 2W1 Canada State Key Laboratory of Computer Science Institute of Software Chinese Academy of Sciences Beijing 100190 China Joint Center for Quantum Information and Computer Science University of Maryland College Park Maryland 20742 USA Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics University of Science and Technology of China Hefei Anhui 230036 China Canadian Institute for Advanced Research Toronto Ontario M5G 1Z8 Canada Perimeter Institute for Theoretical Physics Waterloo Ontario N2L 2Y5 Canada

Entanglement, one of the central mysteries of quantum mechanics, plays an essential role in numerous tasks of quantum information science. A natural question of both theoretical and experimental importance is whether universal entanglement detection can be accomplished without full state tomography. In this Letter, we prove a no-go theorem that rules out this possibility for nonadaptive schemes that employ single-copy measurements only. We also examine a previously implemented experiment [H. Park et al., Phys. Rev. Lett. 105, 230404 (2010)], which claimed to detect entanglement of two-qubit states via adaptive single-copy measurements without full state tomography. In contrast, our simulation and experiment both support the opposite conclusion that the protocol, indeed, leads to full state tomography, which supplements our no-go theorem. These results reveal a fundamental limit of single-copy measurements in entanglement detection and provide a general framework of the detection of other interesting properties of quantum states, such as the positivity of partial transpose and the k-symmetric extendibility.

关键词： Entanglement detection Entanglement measures Quantum tomography Nuclear magnetic resonance

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Are There Signatures of Harmonic Oscillator Shells Far from Stability? First Spectroscopy of Zr110

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Physical Review Letters 2017年第3期118卷 032501-032501页

作者： N. Paul A. Corsi A. Obertelli P. Doornenbal G. Authelet H. Baba B. Bally M. Bender D. Calvet F. Château S. Chen J.-P. Delaroche A. Delbart J.-M. Gheller A. Giganon A. Gillibert M. Girod P.-H. Heenen V. Lapoux J. Libert T. Motobayashi M. Niikura T. Otsuka T. R. Rodríguez J.-Y. Roussé H. Sakurai C. Santamaria N. Shimizu D. Steppenbeck R. Taniuchi T. Togashi Y. Tsunoda T. Uesaka T. Ando T. Arici A. Blazhev F. Browne A. M. Bruce R. Carroll L. X. Chung M. L. Cortés M. Dewald B. Ding F. Flavigny S. Franchoo M. Górska A. Gottardo A. Jungclaus J. Lee M. Lettmann B. D. Linh J. Liu Z. Liu C. Lizarazo S. Momiyama K. Moschner S. Nagamine N. Nakatsuka C. Nita C. R. Nobs L. Olivier Z. Patel Zs. Podolyák M. Rudigier T. Saito C. Shand P.-A. Söderström I. Stefan R. Orlandi V. Vaquero V. Werner K. Wimmer Z. Xu IRFU CEA Université Paris-Saclay F-91191 Gif-sur-Yvette France RIKEN Nishina Center 2-1 Hirosawa Wako Saitama 351-0198 Japan ESNT IRFU CEA Université Paris-Saclay F-91191 Gif-sur-Yvette France IPNL Université de Lyon Université Lyon 1 CNRS/IN2P3 F-69622 Villeurbanne France School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking University Beijing 100871 People’s Republic of China CEA DAM DIF F-91297 Arpajon France PNTPM CP229 Université Libre de Bruxelles B-1050 Bruxelles Belgium Department of Physics University of Tokyo 7-3-1 Hongo Bunkyo Tokyo 113-0033 Japan Departamento de Física Teorica Universidad Autónoma de Madrid 28049 Madrid Spain Center for Nuclear Study University of Tokyo 7-3-1 Hongo Bunkyo Tokyo 113-0033 Japan GSI Helmholtzzentrum für Schwerionenforschung GmbH 64291 Darmstadt Germany Justus-Liebig-Universität Giessen D-35392 Giessen Germany Institut für Kernphysik Universität zu Köln 50937 Köln Germany School of Computing Engineering and Mathematics University of Brighton Brighton BN2 4GJ United Kingdom Department of Physics University of Surrey Guildford GU2 7XH United Kingdom Institute for Nuclear Science and Technology VAEI 179 Hoang Quoc Viet Cau Giay Hanoi Vietnam Institut für Kernphysik Technische Universität Darmstadt 64289 Darmstadt Germany Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 People’s Republic of China Institut de Physique Nucléaire CNRS-IN2P3 Université Paris—Sud Université Paris-Saclay 91406 Orsay Cedex France Instituto de Estructura de la Materia CSIC 28006 Madrid Spain Department of Physics The University of Hong Kong Pokfulam Hong Kong Department of Physics Faculty of Science Kyoto University Kyoto 606-8502 Japan Horia Hulubei National Institute of Physics and Nuclear Engineering (IFIN-HH) RO-077125 Bucharest Romania Advanced Science Research Center Japan Atomic Energy Agency Tokai Ibaraki 319-1195 Japan

The first measurement of the low-lying states of the neutron-rich Zr110 and Mo112 was performed via in-beam γ-ray spectroscopy after one proton removal on hydrogen at ∼200 MeV/nucleon. The 21+ excitation energies were found at 185(11) keV in Zr110, and 235(7) keV in Mo112, while the R42=E(41+)/E(21+) ratios are 3.1(2), close to the rigid rotor value, and 2.7(1), respectively. These results are compared to modern energy density functional based configuration mixing models using Gogny and Skyrme effective interactions. We conclude that first levels of Zr110 exhibit a rotational behavior, in agreement with previous observations of lighter zirconium isotopes as well as with the most advanced Monte Carlo shell model predictions. The data, therefore, do not support a harmonic oscillator shell stabilization scenario at Z=40 and N=70. The present data also invalidate predictions for a tetrahedral ground state symmetry in Zr110.

关键词： Energy levels & level densities Nuclear structure & decays Rare & new isotopes 90 ≤ A ≤ 149 Collective models Nuclear density functional theory Radioactive beams Shell model Spectrometers & spectroscopic techniques

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The GALAH survey: Chemical Tagging of Star Clusters and New Members in the Pleiades

arXiv

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arXiv 2017年

作者： Kos, Janez Bland-Hawthorn, Joss Freeman, Ken Buder, Sven Traven, Gregor de Silva, Gayandhi M. Sharma, Sanjib Asplund, Martin Duong, Ly Lin, Jane Lind, Karin Martell, Sarah Simpson, Jeffrey D. Stello, Dennis Zucker, Daniel B. Zwitter, Tomaž Anguiano, Borja Costa, Gary Da Horner, Jonathan Kafle, Prajwal R. Lewis, Geraint Munari, Ulisse Nataf, David M. Ness, Melissa Reid, Warren Schlesinger, Katie Ting, Yuan-Sen Wyse, Rosemary Sydney Institute for Astronomy School of Physics University of Sydney A28 NSW2006 Australia Research School of Astronomy & Astrophysics Australian National University ACT2611 Australia Max-Planck-Institut for Astronomy Königstuhl 17 HeidelbergD-69117 Germany Faculty of Mathematics and Physics University of Ljubljana Jadranska 19 Ljubljana1000 Slovenia Australian Astronomical Observatory North RydeNSW2133 Australia Department of Physics and Astronomy Uppsala University Box 516 UppsalaSE-751 20 Sweden School of Physics UNSW SydneyNSW2052 Australia Department of Physics and Astronomy Macquarie Univeristy SydneyNSW2109 Australia Stellar Astrophysics Centre Department of Physics and Astronomy Aarhus University Aarhus CDK-8000 Denmark Department of Astronomy University of Virginia CharlottesvilleVA22904-4325 United States Computational Engineering and Science Research Centre University of Southern Queensland ToowoombaQLD4350 Australia 35 Stirling Highway CRAWLEYWA6009 Australia INAF National Institute of Astrophysics Astronomical Observatory of Padova 36012 Asiago Itay Center for Astrophysical Sciences Department of Physics and Astronomy Johns Hopkins University BaltimoreMD21218 Western Sydney University Locked Bag 1797 Penrith South DCNSW2751 Australia

The technique of chemical tagging uses the elemental abundances of stellar atmospheres to ‘reconstruct’ chemically homogeneous star clusters that have long since dispersed. The GALAH spectroscopic survey –which aims to observe one million stars using the Anglo-Australian Telescope – allows us to measure up to 30 elements or dimensions in the stellar chemical abundance space, many of which are not independent. How to find clustering reliably in a noisy high-dimensional space is a difficult problem that remains largely unsolved. Here we explore t-distributed stochastic neighbour embedding (t-SNE) – which identifies an optimal mapping of a high-dimensional space into fewer dimensions – whilst conserving the original clustering information. Typically, the projection is made to a 2D space to aid recognition of clusters by eye. We show that this method is a reliable tool for chemical tagging because it can: (i) resolve clustering in chemical space alone, (ii) recover known open and globular clusters with high efficiency and low contamination, and (iii) relate field stars to known clusters. t-SNE also provides a useful visualization of a high-dimensional space. We demonstrate the method on a dataset of 13 abundances measured in the spectra of 187,000 stars by the GALAH survey. We recover 7 of the 9 observed clusters (6 globular and 3 open clusters) in chemical space with minimal contamination from field stars and low numbers of outliers. With chemical tagging, we also identify two Pleiades supercluster members (which we confirm kinematically), one as far as 6◦ – one tidal radius away from the cluster centre. Copyright © 2017, The Authors. All rights reserved.

关键词： Stars

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