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Constraining black holes with light boson hair and boson stars using epicyclic frequencies and quasiperiodic oscillations

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Physical Review D 2017年第12期95卷 124025-124025页

作者： Nicola Franchini Paolo Pani Andrea Maselli Leonardo Gualtieri Carlos A. R. Herdeiro Eugen Radu Valeria Ferrari Dipartimento di Fisica “Sapienza” Università di Roma & Sezione INFN Roma1 Piazzale Aldo Moro 5 00185 Roma Italy School of Mathematical Sciences University of Nottingham University Park Nottingham NG7 2RD United Kingdom CENTRA Departamento de Física Instituto Superior Técnico—IST Universidade de Lisboa—UL Avenida Rovisco Pais 1 1049 Lisboa Portugal Theoretical Astrophysics Eberhard Karls University of Tuebingen Tuebingen 72076 Germany Departamento de Física da Universidade de Aveiro and Center for Research and Development in Mathematics and Applications (CIDMA) Campus de Santiago 3810-183 Aveiro Portugal

Light bosonic fields are ubiquitous in extensions of the Standard Model. Even when minimally coupled to gravity, these fields might evade the assumptions of the black-hole no-hair theorems and give rise to spinning black holes which can be drastically different from the Kerr metric. Furthermore, they allow for self-gravitating compact solitons, known as (scalar or Proca) boson stars. The quasiperiodic oscillations (QPOs) observed in the x-ray flux emitted by accreting compact objects carry information about the strong-field region, thus providing a powerful tool to constrain deviations from Kerr’s geometry and to search for exotic compact objects. By using the relativistic precession model as a proxy to interpret the QPOs in terms of geodesic frequencies, we investigate how the QPO frequencies could be used to test the no-hair theorem and the existence of light bosonic fields near accreting compact objects. We show that a detection of two QPO triplets with current sensitivity can already constrain these models and that the future eXTP mission or a LOFT-like mission can set very stringent constraints on black holes with bosonic hair and on (scalar or Proca) boson stars. The peculiar geodesic structure of compact scalar/Proca boson stars implies that these objects can easily be ruled out as alternative models for x-ray source GRO J1655-40.

关键词： Alternative gravity theories Classical black holes Particle astrophysics X ray astronomy

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Cell formation problem: A genetic algorithm based on an inter-operation flow matrix 45

Cell formation problem: A genetic algorithm based on an inte...

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45th International Conference on Computers and Industrial Engineering, CIE 2015

作者： Xambre, A.R. Department of Economics Management and Industrial Engineering CIDMA Center for Research and Development in Mathematics and Applications University of Aveiro Campus de Santiago Aveiro3810-193 Portugal

When designing a Cellular Manufacturing System an essential step is to solve the cell formation problem: determining which machines and parts belong to each cell. The main purpose is to obtain autonomous cells capable of completely processing the respective family of parts and thus eliminate, or at least reduce, intercellular flow. Additionally, if there is more than one machine of each type (i.e. if a certain operation can be performed in different machines) the assignment of operations to specific machines becomes part of the cell formation problem. In this paper an algorithm for the cell formation problem with multiple identical machines, which minimises the intercellular flow, is presented. The algorithm uses the information provided by an inter-operation flow matrix so the real flow, associated with each solution, can be adequately determined. Furthermore, due to the combinatorial nature of this problem, the procedure is based on genetic algorithms in order to improve the exploration of the solution space.

关键词： Genetic algorithms

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An overview from hygroscopic aerosols to cloud droplets: The HygrA-CD campaign in the Athens basin

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Science of The Total Environment 2017年 574卷 216-233页

作者： A. Papayannis A. Argyrouli A. Bougiatioti E. Remoundaki S. Vratolis A. Nenes S. Solomos M. Komppula E. Giannakaki J. Kalogiros R. Banks K. Eleftheriadis E. Mantas E. Diapouli C.G. Tzanis S. Kazadzis I. Binietoglou L. Labzovskii C.S. Zerefos Laser Remote Sensing Unit Physics Department School of Applied Mathematics and Physical Sciences National Technical University of Athens 15780 Zografou Greece School of Earth & Atmospheric Sciences Georgia Institute of Technology Atlanta 30332 GA USA Laboratory of Environmental Science and Engineering School of Mining and Metallurgical Engineering National Technical University of Athens 15780 Zografou Greece ERL INRSTES N.C.S.R. Demokritos 15310 Agia Paraskevi Attiki Greece ICE-HT Foundation for Research and Technology Hellas 26504 Patras Greece Institute of Environmental Research and Sustainable Development National Observatory of Athens Athens Greece School of Chemical & Biomolecular Engineering Georgia Institute of Technology Atlanta 30332 GA USA Institute for Astronomy Astrophysics Space Applications and Remote Sensing National Observatory of Athens Athens Greece Finnish Meteorological Institute Kuopio Finland Department of Environmental Physics and Meteorology Faculty of Physics University of Athens Athens Greece Barcelona Supercomputing Center-Centro Nacional de Supercomputación (BSC-CNS) Earth Sciences Department Jordi Girona 29 Edificio Nexus II Barcelona Spain Environmental Modelling Laboratory Polytechnic University of Catalonia Barcelona Spain Climate Research Group Division of Environmental Physics and Meteorology Department of Physics National and Kapodistrian University of Athens 15784 Athens Greece Physikalisch-Meteorologisches Observatorium Davos World Radiation Center Switzerland National Institute of Research and Development for Optoelectronics Magurele Romania Research Center of Ecological Safety Russian Academy of Sciences St. Petersburg Russia Biomedical Research Foundation of the Academy of Athens Athens Greece Navarino Environmental Observatory (N.E.O.) Messinia Greece

The international experimental campaign Hygroscopic Aerosols to Cloud Droplets (HygrA-CD), organized in the Greater Athens Area (GAA), Greece from 15 May to 22 June 2014, aimed to study the physico-chemical properties of aerosols and their impact on the formation of clouds in the convective Planetary Boundary Layer (PBL). We found that under continental (W-NW-N) and Etesian (NE) synoptic wind flow and with a deep moist PBL (~ 2–2.5 km height), mixed hygroscopic (anthropogenic, biomass burning and marine) particles arrive over the GAA, and contribute to the formation of convective non-precipitating PBL clouds (with droplets of ~ 16–20 μm mean diameter) with vertical extent up to 500 m. Under these conditions, high updraft velocities (1–2 m s − 1 ) and cloud condensation nuclei (CCN) concentrations (~ 2000 cm − 3 at 1% supersaturation), generated clouds with an estimated cloud droplet number of ~ 600 cm − 3 . Under Saharan wind flow conditions (S-SW) a shallow PBL (< 1–1.2 km height) develops, leading to much higher CCN concentrations (~ 3500–5000 cm − 3 at 1% supersaturation) near the ground; updraft velocities, however, were significantly lower, with an estimated maximum cloud droplet number of ~ 200 cm − 3 and without observed significant PBL cloud formation. The largest contribution to cloud droplet number variance is attributed to the updraft velocity variability, followed by variances in aerosol number concentration.

关键词： Aerosol Raman lidar Doppler lidar Precipitation radar SMPS CCN Aerosol chemical properties WRF FLEXPART model Cloud development Cloud droplet number HygrA-CD Athens Greece

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Advanced Methods in the Fractional Calculus of Variations 1

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丛书名： SpringerBriefs in Applied Sciences and Technology

2015年

作者： Agnieszka B. Malinowska, Tatiana Odzijewicz, Delfim F.M. Torres (auth.)

ISBN: (数字)9783319147567

ISBN: (纸本)9783319147550;9783319147567

This brief presents a general unifying perspective on the fractional calculus. It brings together results of several recent approaches in generalizing the least action principle and the EulerLagrange equations to include fractional *** dependence of Lagrangians on generalized fractional operators as well as on classical derivatives is considered along with still more general problems in which integer-order integrals are replaced by fractional integrals. General theorems are obtained for several types of variational problems for which recent results developed in the literature can be obtained as special cases. In particular, the authors offer necessary optimality conditions of EulerLagrange type for the fundamental and isoperimetric problems, transversality conditions, and Noether symmetry theorems. The existence of solutions is demonstrated under Tonelli type conditions. The results are used to prove the existence of eigenvalues and corresponding orthogonal eigenfunctions of fractional SturmLiouville *** Methods in the Fractional Calculus of Variations is a self-contained text which will be useful for graduate students wishing to learn about fractional-order systems. The detailed explanations will interest researchers with backgrounds in applied mathematics, control and optimization as well as in certain areas of physics and engineering.

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Some operational properties of the Laguerre transform

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AIP Conference Proceedings 2017年第1期1798卷

作者： M. M. Rodrigues V. N. Huy N. M. Tuan 1CIDMA - Center for Research and Development in Mathematics and Applications Department of Mathematics University of Aveiro Campus Universitário de Santiago 3810-193 Aveiro Portugal 2Department of Mathematics College of Science Vietnam National University 334 Nguyen Trai Thanh Xuan Hanoi Vietnam 3Dept. of Mathematics College of Education Vietnam National University G7 Build 144 Xuan Thuy Rd. Cau Giay Dist. Hanoi Vietnam

This paper is devoted to the study of some properties of the Laguerre transform. We define new properties of the Laguerre transform in a weighted L2–space. Moreover, we present some results concerning the action of t...

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Generalized Krein Parameters of a Strongly Regular Graph

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Applied mathematics 2015年第1期6卷 37-45页

作者： Luis Almeida Vieira Vasco Moco Mano CMUP—Center of Research of Mathematics of University of Porto Department of Civil EngineeringUniversity of PortoPortoPortugal CIDMA—Center for Research and Development in Mathematics and Applications Department of MathematicsUniversity of AveiroAveiroPortugal

We consider the real three-dimensional Euclidean Jordan algebra associated to a strongly regular graph. Then, the Krein parameters of a strongly regular graph are generalized and some generalized Krein admissibility conditions are deduced. Furthermore, we establish some relations between the classical Krein parameters and the generalized Krein parameters.

关键词： Algebraic Combinatorics Association Schemes Strongly Regular Graphs Graphs and Linear Algebra

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Erratum to: Individualizing propofol dosage: a multivariate linear model approach

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Journal of clinical monitoring and computing 2017年第1期31卷 239页

作者： Conceição Rocha Teresa Mendonça Maria Eduarda Silva Pedro Gambús Faculdade de Ciências da Universidade do Porto Rua do Campo Alegre 4169-007 Porto Portugal. mnrocha@fc.up.pt. Center for Research & Development in Mathematics and Applications (CIDMA) Aveiro Portugal. mnrocha@fc.up.pt. Faculdade de Ciências da Universidade do Porto Rua do Campo Alegre 4169-007 Porto Portugal. Center for Research & Development in Mathematics and Applications (CIDMA) Aveiro Portugal. Faculdade de Economia da Universidade do Porto Rua Dr. Roberto Frias 4200-464 Porto Portugal. Systems Pharmacology Effect Control and Modeling (SPEC-M) Research Group Department of Anesthesia Hospital CLINIC de Barcelona and Neuroimmunology Research Group Institut d'Investigacions Biomédiques August Pi i Sunyer (IDIBAPS) Barcelona Spain. Department of Anesthesia and Perioperative Care University of California San Francisco (UCSF) San Francisco CA USA.

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Implementation of behavioral systems

Lecture Notes in Control and Information Sciences

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Lecture Notes in Control and Information Sciences 2015年 462卷 151-168页

作者： Napp, Diego Rocha, Paula Department of Mathematics CIDMA – Center for Research and Development in Mathematics and Applications University of Aveiro Campus Universitario de Santiago Aveiro3810-193 Portugal Department of Electrical and Computer Engineering SYSTEC - Research Center for Systems and Technologies University of Porto Porto Portugal

In this chapter, we study control by interconnection of a given linear differential system (the plant behavior) with a suitable controller. The problem formulations and their solutions are completely representation free, and specified only in terms of the system dynamics. A controller is a system that constrains the plant behavior through a certain set of variables. In this context, there are two main situations to be considered: either all the system variables are available for control, i.e., are control variables (full control) or only some of the variables are control variables (partial control). For systems evolving over a time domain (1D) the problems of implementability by partial (regular) interconnection are well understood. In this chapter, we study why similar results are not valid in themultidimensional (nD) case. Finally, we study two important classes of controllers, namely, canonical controllers and regular controllers. © Springer International Publishing Switzerland 2015.

关键词： Controllers

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A study on massive open online courses in higher education 15

A study on massive open online courses in higher education

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15th Portuguese Association for Information Systems Conference, CAPSI 2015

作者： Costa, Carolina Teixeira, Leonor Alvelos, Helena Department of Economics Management and Industrial Engineering University of Aveiro Portugal IEETA - Institute of Electronics and Telematics Engineering of Aveiro Department of Economics Management and Industrial Engineering University of Aveiro Portugal CIDMA - Center for Research and Development in Mathematics and Applications Department of Economics Management and Industrial Engineering University of Aveiro Portugal

In this paper the current usage of active Massive Open Line Courses (MOCC) is analysed. First a systematic literature revision is performed, in order to identify and classify the published works and the existing developments in this area, being the most used MOOCs platforms also found out. Afterwards, a content analysis of the two most popular MOOCs’ platforms – Coursera and EdX – and a comparison between them is performed. This analysis takes into account, among others, the number and areas of knowledge of the accessible courses, the Higher Education Institutions (HEI) that offer courses using the platforms, the length of the courses and the expected workload for a student to successfully complete the MOOCs. The main findings were that the use of MOOCs has been growing in the last years and that Coursera and EdX are the two main platforms used by HEIs in order to make MOCCs available. © 2015 Associacao Portuguesa de Sistemas de Informacao. All rights reserved.

关键词： E-learning

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An institution for Alloy and its translation to second-order logic

Advances in Intelligent Systems and Computing

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Advances in Intelligent Systems and Computing 2014年 263卷 45-75页

作者： Neves, Renato Madeira, Alexandre Martins, Manuel Barbosa, Luís University of Minho Braga Portugal Department of Mathematics University of Aveiro Aveiro Portugal Center for Research and Development in Mathematics and Applications Department of Mathematics University of Aveiro Aveiro Portugal

Lightweight formal methods, of which Alloy is a prime example, combine the rigour of mathematics without compromising simplicity of use and suitable tool support. In some cases, however, the verification of safety or mission critical software entails the need formore sophisticated technologies, typically based on theorem provers. This explains a number of attempts to connect Alloy to specific theorem provers documented in the literature. This chapter, however, takes a different perspective: instead of focusing on one more combination of Alloy with still another prover, it lays out the foundations to fully integrate this system in the Hets platform which supports a huge network of logics, logic translators and provers. This makes possible for Alloy specifications to "borrow" the power of several, non dedicated proof systems. The chapter extends the authors’ previous work on this subject by developing in full detail the semantical foundations for this integration, including a formalisation of Alloy as an institution, and introducing a new, more general translation of the latter to second-order logic. © Springer International Publishing Switzerland 2014.

关键词： Theorem proving

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