检索结果-内蒙古大学图书馆

Global investments in pandemic preparedness and COVID-19: development assistance and domestic spending on health between 1990 and 2026

学校读者我要写书评

暂无评论

The Lancet Global Health 2023年第3期11卷 e385-e413页

作者： Micah, Angela E. Bhangdia, Kayleigh Cogswell, Ian E. Lasher, Dylan Lidral-Porter, Brendan Maddison, Emilie R. Nguyen, Trang Nhu Ngoc Patel, Nishali Pedroza, Paola Solorio, Juan Stutzman, Hayley Tsakalos, Golsum Wang, Yifeng Warriner, Wesley Zhao, Yingxi Zlavog, Bianca S. Abbafati, Cristiana Abbas, Jaffar Abbasi-Kangevari, Mohsen Abbasi-Kangevari, Zeinab Abdelmasseh, Michael Abdulah, Deldar Morad Abedi, Aidin Abegaz, Kedir Hussein Abhilash, E.S. Aboagye, Richard Gyan Abolhassani, Hassan Abrigo, Michael R.M. Abubaker Ali, Hiwa Abu-Gharbieh, Eman Adem, Mohammed Hussien Afzal, Muhammad Sohail Ahmadi, Ali Ahmed, Haroon Ahmed Rashid, Tarik Aji, Budi Akbarialiabad, Hossein Akelew, Yibeltal Al Hamad, Hanadi Alam, Khurshid Alanezi, Fahad Mashhour Alanzi, Turki M. Al-Hanawi, Mohammed Khaled Alhassan, Robert Kaba Aljunid, Syed Mohamed Almustanyir, Sami Al-Raddadi, Rajaa M. Alvis-Guzman, Nelson Alvis-Zakzuk, Nelson J. Amare, Azmeraw T. Ameyaw, Edward Kwabena Amini-Rarani, Mostafa Amu, Hubert Ancuceanu, Robert Andrei, Tudorel Anwar, Sumadi Lukman Appiah, Francis Aqeel, Muhammad Arabloo, Jalal Arab-Zozani, Morteza Aravkin, Aleksandr Y. Aremu, Olatunde Aruleba, Raphael Taiwo Athari, Seyyed Shamsadin Avila-Burgos, Leticia Ayanore, Martin Amogre Azari, Samad Baig, Atif Amin Bantie, Abere Tilahun Barrow, Amadou Baskaran, Pritish Basu, Sanjay Batiha, Abdul-Monim Mohammad Baune, Bernhard T. Berezvai, Zombor Bhardwaj, Nikha Bhardwaj, Pankaj Bhaskar, Sonu Boachie, Micheal Kofi Bodolica, Virginia Botelho, João Silva Botelho Braithwaite, Dejana Breitborde, Nicholas J.K. Busse, Reinhard Cahuana-Hurtado, Lucero Catalá-López, Ferrán Chansa, Collins Charan, Jaykaran Chattu, Vijay Kumar Chen, Simiao Chukwu, Isaac Sunday Dadras, Omid Dandona, Lalit Dandona, Rakhi Dargahi, Abdollah Debela, Sisay Abebe Denova-Gutiérrez, Edgar Desye, Belay Dharmaratne, Samath Dhamminda Diao, Nancy Doan, Linh Phuong Dodangeh, Milad dos Santos, Wendel Mombaque Doshmangir, Leila Dube, John Eini, Ebrahim El Sayed Zaki, Maysaa El Tantawi, Maha Enyew, Daniel Berhanie Institute for Health Metrics and Evaluation University of Washington Seattle WA United States Department of Applied Mathematics University of Washington Seattle WA United States Department of Health Metrics Sciences School of Medicine University of Washington Seattle WA United States Nuffield Department of Medicine University of Oxford Oxford United Kingdom Department of Juridical and Economic Studies La Sapienza University Rome Italy Antai College of Economics Shanghai Jiao Tong University Shanghai China Non-communicable Diseases Research Center Tehran University of Medical Sciences Tehran Iran Research Center for Immunodeficiencies Tehran University of Medical Sciences Tehran Iran Multiple Sclerosis Research Center Tehran University of Medical Sciences Tehran Iran Children’s Medical Center Tehran University of Medical Sciences Tehran Iran Department of Epidemiology and Biostatistics Tehran University of Medical Sciences Tehran Iran Tehran Heart Center Tehran University of Medical Sciences Tehran Iran Faculty of Medicine Tehran University of Medical Sciences Tehran Iran National Institute for Health Research Tehran University of Medical Sciences Tehran Iran Department of Pharmacology Tehran University of Medical Sciences Tehran Iran Department of Cardiology Tehran University of Medical Sciences Tehran Iran Sina Trauma and Surgery Research Center Tehran University of Medical Sciences Tehran Iran Digestive Diseases Research Institute Tehran University of Medical Sciences Tehran Iran Department of Neurology Tehran University of Medical Sciences Tehran Iran Social Determinants of Health Research Center Shahid Beheshti University of Medical Sciences Tehran Iran Department of Epidemiology Shahid Beheshti University of Medical Sciences Tehran Iran Department of Health Economics and Statistics Shahid Beheshti University of Medical Sciences Tehran Iran Department of Neurosurgery Shahid Beheshti University of Medical Sciences Tehran Iran Ophthalmic R

Background: The COVID-19 pandemic highlighted gaps in health surveillance systems, disease prevention, and treatment globally. Among the many factors that might have led to these gaps is the issue of the financing of national health systems, especially in low-income and middle-income countries (LMICs), as well as a robust global system for pandemic preparedness. We aimed to provide a comparative assessment of global health spending at the onset of the pandemic;characterise the amount of development assistance for pandemic preparedness and response disbursed in the first 2 years of the COVID-19 pandemic;and examine expectations for future health spending and put into context the expected need for investment in pandemic preparedness. Methods: In this analysis of global health spending between 1990 and 2021, and prediction from 2021 to 2026, we estimated four sources of health spending: development assistance for health (DAH), government spending, out-of-pocket spending, and prepaid private spending across 204 countries and territories. We used the Organisation for Economic Co-operation and Development (OECD)'s Creditor Reporting System (CRS) and the WHO Global Health Expenditure Database (GHED) to estimate spending. We estimated development assistance for general health, COVID-19 response, and pandemic preparedness and response using a keyword search. Health spending estimates were combined with estimates of resources needed for pandemic prevention and preparedness to analyse future health spending patterns, relative to need. Findings: In 2019, at the onset of the COVID-19 pandemic, US$9·2 trillion (95% uncertainty interval [UI] 9·1–9·3) was spent on health worldwide. We found great disparities in the amount of resources devoted to health, with high-income countries spending $7·3 trillion (95% UI 7·2–7·4) in 2019;293·7 times the $24·8 billion (95% UI 24·3–25·3) spent by low-income countries in 2019. That same year, $43·1 billion in development assistance was provided

关键词：

Jet modification via π0-hadron correlations in Au+Au collisions at sNN=200 GeV

学校读者我要写书评

暂无评论

Physical Review C 2024年第4期110卷 044901页

作者： N. J. Abdulameer U. Acharya A. Adare S. Afanasiev C. Aidala N. N. Ajitanand Y. Akiba H. Al-Bataineh J. Alexander M. Alfred K. Aoki N. Apadula L. Aphecetche J. Asai H. Asano E. T. Atomssa R. Averbeck T. C. Awes B. Azmoun V. Babintsev M. Bai G. Baksay L. Baksay A. Baldisseri N. S. Bandara B. Bannier K. N. Barish P. D. Barnes B. Bassalleck A. T. Basye S. Bathe S. Batsouli V. Baublis C. Baumann A. Bazilevsky M. Beaumier S. Beckman S. Belikov R. Belmont R. Bennett A. Berdnikov Y. Berdnikov L. Bichon A. A. Bickley B. Blankenship D. S. Blau J. G. Boissevain J. S. Bok H. Borel V. Borisov K. Boyle M. L. Brooks J. Bryslawskyj H. Buesching V. Bumazhnov G. Bunce S. Butsyk C. M. Camacho S. Campbell B. S. Chang W. C. Chang J. L. Charvet C.-H. Chen D. Chen S. Chernichenko M. Chiu C. Y. Chi I. J. Choi J. B. Choi R. K. Choudhury T. Chujo P. Chung A. Churyn V. Cianciolo Z. Citron B. A. Cole M. Connors P. Constantin R. Corliss M. Csanád T. Csörgő D. d'Enterria T. Dahms S. Dairaku T. W. Danley K. Das A. Datta M. S. Daugherity G. David K. DeBlasio K. Dehmelt A. Denisov A. Deshpande E. J. Desmond O. Dietzsch A. Dion P. B. Diss M. Donadelli V. Doomra J. H. Do O. Drapier A. Drees K. A. Drees A. K. Dubey J. M. Durham A. Durum D. Dutta V. Dzhordzhadze Y. V. Efremenko F. Ellinghaus H. En'yo T. Engelmore A. Enokizono R. Esha K. O. Eyser B. Fadem N. Feege D. E. Fields M. Finger, Jr. M. Finger D. Firak D. Fitzgerald F. Fleuret S. L. Fokin Z. Fraenkel J. E. Frantz A. Franz A. D. Frawley K. Fujiwara Y. Fukao T. Fusayasu P. Gallus C. Gal P. Garg I. Garishvili H. Ge F. Giordano A. Glenn H. Gong M. Gonin J. Gosset Y. Goto R. Granier de Cassagnac N. Grau S. V. Greene M. Grosse Perdekamp T. Gunji T. Guo H.-Å. Gustafsson T. Hachiya A. Hadj Henni J. S. Haggerty K. I. Hahn H. Hamagaki H. F. Hamilton J. Hanks R. Han S. Y. Han E. P. Hartouni K. Haruna S. Hasegawa T. O. S. Haseler K. Hashimoto E. Haslum R. Hayano M. Heffner T. K. Hemmick T. Hester X. He J. C. Hill A. Hodges M. Hohlmann R. S. Hollis W. Holzmann K. Homma B. Hong T. Horaguchi D. Hornback T. Debrecen University H-4010 Debrecen Egyetem tér 1 Hungary HUN-REN ATOMKI H-4026 Debrecen Bem tér 18/c Hungary Atlanta Georgia 30303 USA University of Colorado Boulder Colorado 80309 USA Joint Institute for Nuclear Research 141980 Dubna Moscow Region Russia Department of Physics University of Massachusetts Amherst Massachusetts 01003-9337 USA Department of Physics University of Michigan Ann Arbor Michigan 48109-1040 USA Chemistry Department Stony Brook University SUNY Stony Brook New York 11794-3400 USA RIKEN Nishina Center for Accelerator-Based Science Wako Saitama 351-0198 Japan RIKEN BNL Research Center New Mexico State University Las Cruces New Mexico 88003 USA Department of Physics and Astronomy Howard University Washington DC 20059 USA KEK High Energy Accelerator Research Organization Tsukuba Ibaraki 305-0801 Japan Kyoto University Kyoto 606-8502 Japan Iowa State University Ames Iowa 50011 USA Department of Physics and Astronomy Stony Brook University SUNY Stony Brook New York 11794-3800 USA SUBATECH (Ecole des Mines de Nantes CNRS-IN2P3 Université de Nantes) BP 20722-44307 Nantes France Laboratoire Leprince-Ringuet Ecole Polytechnique CNRS-IN2P3 Route de Saclay F-91128 Palaiseau France Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA Physics Department IHEP Protvino State Research Center of Russian Federation Institute for High Energy Physics Protvino 142281 Russia Collider-Accelerator Department Florida Institute of Technology Melbourne Florida 32901 USA Dapnia CEA Saclay F-91191 Gif-sur-Yvette France University of California-Riverside Riverside California 92521 USA Los Alamos National Laboratory Los Alamos New Mexico 87545 USA University of New Mexico Albuquerque New Mexico 87131 USA Abilene Christian University Abilene Texas 79699 USA Baruch College City University of New York New York New York 10010 USA PNPI Petersburg Nuclear Physics Institute Gatchina Leningrad region 188300 Russia Institut für

High-momentum two-particle correlations are a useful tool for studying jet-quenching effects in the quark-gluon plasma. Angular correlations between neutral-pion triggers and charged hadrons with transverse momenta in the range 4–12 GeV/c and 0.5–7 GeV/c, respectively, have been measured by the PHENIX experiment in 2014 for Au+Au collisions at sNN=200 GeV. Suppression is observed in the yield of high-momentum jet fragments opposite the trigger particle, which indicates jet suppression stemming from in-medium partonic energy loss, while enhancement is observed for low-momentum particles. The ratio and differences between the yield in Au+Au collisions and p+p collisions, IAA and ΔAA, as a function of the trigger-hadron azimuthal separation, Δϕ, are measured for the first time at the BNL Relativistic Heavy Ion Collider. These results better quantify how the yield of low-pT associated hadrons is enhanced at wide angle, which is crucial for studying energy loss as well as medium-response effects.

关键词： Particle correlations & fluctuations Relativistic heavy-ion collisions Hadrons Pions Hadron colliders

Scattering of long water waves in a canal with rapidly varying cross-section in the presence of a current

学校读者我要写书评

暂无评论

Physical Review Fluids 2017年第9期2卷 094805-094805页

作者： Semyon Churilov Andrei Ermakov Germain Rousseaux Yury Stepanyants Department of Applied Mathematics Nizhny Novgorod State Technical University Nizhny Novgorod 603950 Russia and School of Agricultural Computational and Environmental Sciences University of Southern Queensland QLD 4350 Australia

The analytical study of long-wave scattering in a canal with a rapidly varying cross-section is presented. It is assumed that waves propagate on a stationary current with a given flow rate. Due to the fixed flow rate, the current speed is different in the different sections of the canal, upstream and downstream. The scattering coefficients (the transmission and reflection coefficients) are calculated for all possible orientations of incident wave with respect to the background current (downstream and upstream propagation) and for all possible regimes of current (subcritical, transcritical, and supercritical). It is shown that in some cases negative energy waves can appear in the process of waves scattering. The conditions are found when the over-reflection and over-transmission phenomena occur. In particular, it is shown that a spontaneous wave generation can arise in a transcritical accelerating flow, when the background current enhances due to the canal narrowing. This resembles a spontaneous wave generation on the horizon of an evaporating black hole due to the Hawking effect.

关键词： Astrophysical fluid dynamics Interfacial flows Oceanography Quantum cosmology

Extrinsic gaussian processes for regression and classification on manifolds

学校读者我要写书评

暂无评论

arXiv 2017年

作者： LIN, LIZHEN NIU, MU CHEUNG, POKMAN DUNSON, DAVID B. Department of Applied and Computational Mathematics and Statistics University of Notre Dame United States School of Mathematics and Statistics University of Glasgow United Kingdom Department of Mathematics Hong Kong University of Science and Technology China Department of Statistical Science Duke University United States

Gaussian processes (GPs) are very widely used for modeling of unknown functions or surfaces in applications ranging from regression to classification to spatial processes. Although there is an increasingly vast literature on applications, methods, theory and algorithms related to GPs, the overwhelming majority of this literature focuses on the case in which the input domain corresponds to a Euclidean space. However, particularly in recent years with the increasing collection of complex data, it is commonly the case that the input domain does not have such a simple form. For example, it is common for the inputs to be restricted to a non-Euclidean manifold, a case which forms the motivation for this article. In particular, we propose a general extrinsic framework for GP modeling on manifolds, which relies on embedding of the manifold into a Euclidean space and then constructing extrinsic kernels for GPs on their images. These extrinsic Gaussian processes (eGPs) are used as prior distributions for unknown functions in Bayesian inferences. Our approach is simple and general, and we show that the eGPs inherit fine theoretical properties from GP models in Euclidean spaces. We consider applications of our models to regression and classification problems with predictors lying in a large class of manifolds, including spheres, planar shape spaces, a space of positive definite matrices, and Grassmannians. Our models can be readily used by practitioners in biological sciences for various regression and classification problems, such as disease diagnosis or detection. Our work is also likely to have impact in spatial statistics when spatial locations are on the sphere or other geometric spaces. Copyright © 2017, The Authors. All rights reserved.

关键词： Gaussian distribution

The Atacama Cosmology Telescope: Probing the baryon content of SDSS DR15 galaxies with the thermal and kinematic Sunyaev-Zel’dovich effects

学校读者我要写书评

暂无评论

Physical Review D 2021年第4期104卷 043503-043503页

作者： E. M. Vavagiakis P. A. Gallardo V. Calafut S. Amodeo S. Aiola J. E. Austermann N. Battaglia E. S. Battistelli J. A. Beall R. Bean J. R. Bond E. Calabrese S. K. Choi N. F. Cothard M. J. Devlin C. J. Duell S. M. Duff A. J. Duivenvoorden J. Dunkley R. Dunner S. Ferraro Y. Guan J. C. Hill G. C. Hilton M. Hilton R. Hložek Z. B. Huber J. Hubmayr K. M. Huffenberger J. P. Hughes B. J. Koopman A. Kosowsky Y. Li M. Lokken M. Madhavacheril J. McMahon K. Moodley S. Naess F. Nati L. B. Newburgh M. D. Niemack L. A. Page B. Partridge E. Schaan A. Schillaci C. Sifón D. N. Spergel S. T. Staggs J. N. Ullom L. R. Vale A. Van Engelen J. Van Lanen E. J. Wollack Z. Xu Department of Physics Cornell University Ithaca New York 14853 USA Department of Astronomy Cornell University Ithaca New York 14853 USA Center for Computational Astrophysics Flatiron Institute New York New York 10010 USA NIST Quantum Sensors Group 325 Broadway Boulder Colorado 80305 USA Physics Department Sapienza University of Rome Piazzale Aldo Moro 5 I-00185 Rome Italy Canadian Institute for Theoretical Astrophysics University of Toronto Toronto Ontario M5S 3H8 Canada School of Physics and Astronomy Cardiff University The Parade Cardiff CF24 3AA United Kingdom Department of Applied and Engineering Physics Cornell University Ithaca New York 14853 USA Department of Physics and Astronomy University of Pennsylvania 209 South 33rd Street Philadelphia Pennsylvania 19104 USA Joseph Henry Laboratories of Physics Jadwin Hall Princeton University Princeton New Jersey 08544 USA Department of Astrophysical Sciences Peyton Hall Princeton University Princeton New Jersey 08544 USA Instituto de Astrofísica and Centro de Astro-Ingeniería Facultad de Física Pontificia Universidad Católica de Chile Avenida Vicuña Mackenna 4860 7820436 Macul Santiago Chile Lawrence Berkeley National Laboratory One Cyclotron Road Berkeley California 94720 USA Berkeley Center for Cosmological Physics UC Berkeley California 94720 USA Department of Physics and Astronomy University of Pittsburgh Pittsburgh Pennsylvania 15260 USA Department of Physics Columbia University New York New York 10027 USA Astrophysics Research Centre University of KwaZulu-Natal Westville Campus Durban 4041 South Africa David A. Dunlap Department of Astronomy and Astrophysics University of Toronto 50 St. George Street Toronto Ontario M5S 3H4 Canada Dunlap Institute for Astronomy and Astrophysics University of Toronto 50 St. George Street Toronto Ontario M5S 3H4 Canada Department of Physics Florida State University Tallahassee Florida 32306 USA Department of Physics and Astronomy Rutgers Th

We present measurements of the average thermal Sunyaev Zel’dovich (tSZ) effect from optically selected galaxy groups and clusters at high signal-to-noise (up to 12σ) and estimate their baryon content within a 2.1′ radius aperture. Sources from the Sloan Digital Sky Survey Baryon Oscillation Spectroscopic Survey DR15 catalog overlap with 3,700 sq deg of sky observed by the Atacama Cosmology Telescope (ACT) from 2008 to 2018 at 150 and 98 GHz (ACT DR5), and 2,089 sq deg of internal linear combination component-separated maps combining ACT and Planck data (ACT DR4). The corresponding optical depths τ¯, which depend on the baryon content of the halos, are estimated using results from cosmological hydrodynamic simulations assuming an active galactic nuclei feedback radiative cooling model. We estimate the mean mass of the halos in multiple luminosity bins, and compare the tSZ-based τ¯ estimates to theoretical predictions of the baryon content for a Navarro-Frenk-White profile. We do the same for τ¯ estimates extracted from fits to pairwise baryon momentum measurements of the kinematic Sunyaev-Zel’dovich effect (kSZ) for the same dataset obtained in a companion paper. We find that the τ¯ estimates from the tSZ measurements in this work and the kSZ measurements in the companion paper agree within 1σ for two out of the three disjoint luminosity bins studied, while they differ by 2–3σ in the highest luminosity bin. The optical depth estimates account for one-third to all of the theoretically predicted baryon content in the halos across luminosity bins. Potential systematic uncertainties are discussed. The tSZ and kSZ measurements provide a step toward empirical Compton-y¯−τ¯ relationships to provide new tests of cluster formation and evolution models.

关键词： Cosmic microwave background Cosmological parameters Cosmology Large scale structure of the Universe

The Atacama Cosmology Telescope: Detection of the pairwise kinematic Sunyaev-Zel’dovich effect with SDSS DR15 galaxies

学校读者我要写书评

暂无评论

Physical Review D 2021年第4期104卷 043502-043502页

作者： V. Calafut P. A. Gallardo E. M. Vavagiakis S. Amodeo S. Aiola J. E. Austermann N. Battaglia E. S. Battistelli J. A. Beall R. Bean J. R. Bond E. Calabrese S. K. Choi N. F. Cothard M. J. Devlin C. J. Duell S. M. Duff A. J. Duivenvoorden J. Dunkley R. Dunner S. Ferraro Y. Guan J. C. Hill G. C. Hilton M. Hilton R. Hložek Z. B. Huber J. Hubmayr K. M. Huffenberger J. P. Hughes B. J. Koopman A. Kosowsky Y. Li M. Lokken M. Madhavacheril J. McMahon K. Moodley S. Naess F. Nati L. B. Newburgh M. D. Niemack L. A. Page B. Partridge E. Schaan A. Schillaci C. Sifón D. N. Spergel S. T. Staggs J. N. Ullom L. R. Vale A. Van Engelen J. Van Lanen E. J. Wollack Z. Xu Department of Astronomy Cornell University Ithaca New York 14853 USA Department of Physics Cornell University Ithaca New York 14853 USA Center for Computational Astrophysics Flatiron Institute New York New York 10010 USA NIST Quantum Devices Group 325 Broadway Mailcode 817.03 Boulder Colorado 80305 USA Physics Department Sapienza University of Rome Piazzale Aldo Moro 5 I-00185 Rome Italy Canadian Institute for Theoretical Astrophysics University of Toronto Toronto Ontario M5S 3H8 Canada School of Physics and Astronomy Cardiff University The Parade Cardiff CF24 3AA United Kingdom Department of Applied and Engineering Physics Cornell University Ithaca New York USA 14853 Department of Physics and Astronomy University of Pennsylvania 209 South 33rd Street Philadelphia Pennsylvania 19104 USA Joseph Henry Laboratories of Physics Jadwin Hall Princeton University Princeton New Jersey 08544 USA Department of Astrophysical Sciences Peyton Hall Princeton University Princeton New Jersey 08544 USA Instituto de Astrofísica and Centro de Astro-Ingeniería Facultad de Física Pontificia Universidad Católica de Chile Avenue Vicuña Mackenna 4860 7820436 Macul Santiago Chile Lawrence Berkeley National Laboratory One Cyclotron Road Berkeley California 94720 USA Berkeley Center for Cosmological Physics UC Berkeley Berkley California 94720 USA Department of Physics and Astronomy University of Pittsburgh Pittsburgh Pennsylvania 15260 USA Department of Physics Columbia University New York New York 10027 USA Astrophysics Research Centre University of KwaZulu-Natal Westville Campus Durban 4041 South Africa David A. Dunlap Department of Astronomy and Astrophysics University of Toronto 50 St. George Street Toronto Ontario M5S 3H4 Canada Dunlap Institute for Astronomy and Astrophysics University of Toronto 50 St. George Street Toronto Ontario M5S 3H4 Canada Department of Physics Florida State University Tallahassee Florida 32306 USA Department of Physics and

We present a 5.4σ detection of the pairwise kinematic Sunyaev-Zeldovich (kSZ) effect using Atacama Cosmology Telescope (ACT) and Planck CMB observations in combination with Luminous Red Galaxy samples from the Sloan Digital Sky Survey (SDSS) DR15 catalog. Results are obtained using three ACT CMB maps: co-added 150 and 98 GHz maps, combining observations from 2008–2018 (ACT DR5), which overlap with SDSS DR15 over 3,700 sq. deg., and a component-separated map using night-time only observations from 2014–2015 (ACT DR4), overlapping with SDSS DR15 over 2,089 sq. deg. Comparisons of the results from these three maps provide consistency checks in relation to potential frequency-dependent foreground contamination. A total of 343,647 galaxies are used as tracers to identify and locate galaxy groups and clusters from which the kSZ signal is extracted using aperture photometry. We consider the impact of various aperture photometry assumptions and covariance estimation methods on the signal extraction. Theoretical predictions of the pairwise velocities are used to obtain best-fit, mass-averaged, optical depth estimates for each of five luminosity-selected tracer samples. A comparison of the kSZ-derived optical depth measurements obtained here to those derived from the thermal SZ effect for the same sample is presented in a companion paper.

关键词： Cosmic microwave background Cosmological parameters Large scale structure of the Universe

Strong wave–mean-flow coupling in baroclinic acoustic streaming

学校读者我要写书评

暂无评论

arXiv 2018年

作者： Michel, Guillaume Chini, Gregory P. Laboratoire de Physique Statistique École Normale Supérieure CNRS Université P. et M. Curie Université Paris Diderot Paris75005 France Department of Mechanical Engineering Program in Integrated Applied Mathematics University of New Hampshire DurhamNH03824 United States

The interaction of an acoustic wave with a stratified fluid can drive strong streaming flows owing to the baroclinic production of fluctuating vorticity, as recently demonstrated by Chini et al. (J. Fluid Mech., 744, 2014, pp. 329–351). In the present investigation, a set of wave/mean-flow interaction equations is derived that governs the coupled dynamics of a standing acoustic-wave mode of characteristic (small) amplitude and the streaming flow it drives in a thin channel with walls maintained at differing temperatures. Unlike classical Rayleigh streaming, the resulting mean flow arises at O() rather than at O(2). Consequently, fully two-way coupling between the waves and the mean flow is possible: the streaming is sufficiently strong to induce O(1) rearrangements of the imposed background temperature and density fields, which modifies the spatial structure and frequency of the acoustic mode on the streaming time scale. A novel Wentzel–Kramers–Brillouin–Jeffreys analysis is developed to average over the fast wave dynamics, enabling the coupled system to be integrated strictly on the slow time scale of the streaming flow. Analytical solutions of the reduced system are derived for weak wave forcing and are shown to reproduce results from prior direct numerical simulations (DNS) of the compressible Navier–Stokes and heat equations with remarkable accuracy. Moreover, numerical simulations of the reduced system are performed in the regime of strong wave/mean-flow coupling for a fraction of the computational cost of the corresponding DNS. These simulations shed light on the potential for baroclinic acoustic streaming to be used as an effective means to enhance heat transfer. Copyright © 2018, The Authors. All rights reserved.

关键词： Numerical models

Mapping electronic states of dual-parallel and symmetric zigzag grain boundaries of graphene on highly oriented pyrolytic graphite

学校读者我要写书评

暂无评论

arXiv 2017年

作者： Ma, Jun Li, Xiaying Yin, Longjing Wang, Wenxiao Sun, Qi Yang, Yu Zhang, Ping Nie, Jiacai Xiong, Changmin Dou, Ruifen Department of Physics Beijing Normal University Beijing100875 China Institute of Applied Physics and Computational Mathematics Beijing100088 China

The grain boundaries (GBs) of a graphene surface were extensively studied because GBs with specific defect configurations result in the formation of new curved structures, which can be treated as new carbon allotropes. We studied the structures and electronic spectra of two periodic GBs in graphene on highly oriented pyrolytic graphite (HOPG) surfaces using scanning tunneling microscopy and spectroscopy (STM/S). Our results demonstrated that a GB consisting of dual parallel periodic dislocation cores of pentagonal-heptagonal (5-7) carbon rings gives rise to an enhanced localized state at 0.45 eV above the Dirac point in graphene surfaces, which is attributed to van Hove singularities (VHSs). Moreover, the energy positions of the localized states are varied between 0.40 and 0.47 eV depending on the site and eventually decayed to 0.36 eV. The variation of the energy positions is induced by two parallel GBs because of the higher electron density at the GB as a defect center and the lower electron away from the GB. Another periodic GB with a symmetric zigzag structural feature induced VHSs at - 0.038 and 0.12 eV near the Fermi level. Moreover, intervalley scattering was observed on both these GBs. This means that carrier concentration and thus, the conductance around the periodic GBs can be significantly enhanced by localized density of states. This finding suggests that graphene with a properly embedded ordered GB is promising for improving the performance of graphene-based electronic devices. Copyright © 2017, The Authors. All rights reserved.

关键词： Graphene

A limited habitable zone for complex life

学校读者我要写书评

暂无评论

arXiv 2019年

作者： Schwieterman, Edward W. Reinhard, Christopher T. Lyons, Timoth W. Olson, Stephanie L. Harman, Chester E. Department of Earth and Planetary Sciences University of California RiversideCA United States NASA Postdoctoral Program Universities Space Research Association ColumbiaMD United States NASA Astrobiology Institute Alternative Earths Team RiversideCA United States Virtual Planetary Laboratory SeattleWA United States Bl M bl S I tit t f S i S ttl W hi t United States School of Earth and Atmospheric Sciences Georgia Institute of Technology AtlantaGA United States De artment of Geo h sical Sciences Universit of Chica o Chica o IL United States NASA Goddard Institute for S ace Studies New YorkNY United States Department of Applied Mathematics and Applied Physics Columbia University New YorkNY United States

The habitable zone (HZ) is commonly defined as the range of distances from a host star within which liquid water, a key requirement for life, may exist on a planet’s surface. Substantially more CO2 than present in Earth’s modern atmosphere is required to maintain clement temperatures for most of the HZ, with several bars required at the outer edge. However, most complex aerobic life on Earth is limited by CO2 concentrations of just fractions of a bar. At the same time, most exoplanets in the traditional HZ reside in proximity to M dwarfs, which are more numerous than Sun-like G dwarfs but are predicted to promote greater abundances of gases that can be toxic in the atmospheres of orbiting planets, such as carbon monoxide (CO). Here we show that the HZ for complex aerobic life is likely limited relative to that for microbial life. We use a 1D radiative-convective climate and photochemical models to circumscribe a Habitable Zone for Complex Life (HZCL) based on known toxicity limits for a range of organisms as a proof of concept. We find that for CO2 tolerances of 0.01, 0.1, and 1 bar, the HZCL is only 21%, 32%, and 50% as wide as the conventional HZ for a Sun-like star, and that CO concentrations may limit some complex life throughout the entire HZ of the coolest M dwarfs. These results cast new light on the likely distribution of complex life in the universe and have important ramifications for the search for exoplanet biosignatures and technosignatures. Copyright © 2019, The Authors. All rights reserved.

关键词： Carbon monoxide