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Publisher: Hindawi   (Total: 334 journals)

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Showing 1 - 200 of 334 Journals sorted alphabetically
Abstract and Applied Analysis     Open Access   (Followers: 3, SJR: 0.512, h-index: 32)
Active and Passive Electronic Components     Open Access   (Followers: 7, SJR: 0.157, h-index: 15)
Advances in Acoustics and Vibration     Open Access   (Followers: 24, SJR: 0.259, h-index: 6)
Advances in Agriculture     Open Access   (Followers: 7)
Advances in Artificial Intelligence     Open Access   (Followers: 14)
Advances in Artificial Neural Systems     Open Access   (Followers: 3)
Advances in Astronomy     Open Access   (Followers: 34, SJR: 0.351, h-index: 17)
Advances in Bioinformatics     Open Access   (Followers: 18, SJR: 0.421, h-index: 8)
Advances in Biology     Open Access   (Followers: 8)
Advances in Chemistry     Open Access   (Followers: 12)
Advances in Civil Engineering     Open Access   (Followers: 33, SJR: 0.338, h-index: 8)
Advances in Condensed Matter Physics     Open Access   (Followers: 8, SJR: 0.248, h-index: 10)
Advances in Decision Sciences     Open Access   (Followers: 4, SJR: 0.231, h-index: 6)
Advances in Ecology     Open Access   (Followers: 13)
Advances in Electrical Engineering     Open Access   (Followers: 18)
Advances in Endocrinology     Open Access   (Followers: 1)
Advances in Fuzzy Systems     Open Access   (Followers: 5, SJR: 0.258, h-index: 7)
Advances in Hematology     Open Access   (Followers: 9, SJR: 0.892, h-index: 18)
Advances in High Energy Physics     Open Access   (Followers: 21, SJR: 0.892, h-index: 19)
Advances in Human-Computer Interaction     Open Access   (Followers: 19, SJR: 0.439, h-index: 9)
Advances in Materials Science and Engineering     Open Access   (Followers: 30, SJR: 0.263, h-index: 11)
Advances in Mathematical Physics     Open Access   (Followers: 6, SJR: 0.332, h-index: 10)
Advances in Medicine     Open Access   (Followers: 3)
Advances in Meteorology     Open Access   (Followers: 18, SJR: 0.498, h-index: 10)
Advances in Multimedia     Open Access   (Followers: 2, SJR: 0.191, h-index: 10)
Advances in Neuroscience     Open Access   (Followers: 8)
Advances in Nonlinear Optics     Open Access   (Followers: 5)
Advances in Numerical Analysis     Open Access   (Followers: 3)
Advances in Nursing     Open Access   (Followers: 21)
Advances in Operations Research     Open Access   (Followers: 11, SJR: 0.343, h-index: 7)
Advances in Optical Technologies     Open Access   (Followers: 3, SJR: 0.283, h-index: 16)
Advances in OptoElectronics     Open Access   (Followers: 5, SJR: 0.973, h-index: 16)
Advances in Orthopedic Surgery     Open Access   (Followers: 9)
Advances in Orthopedics     Open Access   (Followers: 9)
Advances in Pharmacological Sciences     Open Access   (Followers: 5, SJR: 0.695, h-index: 13)
Advances in Physical Chemistry     Open Access   (Followers: 11, SJR: 0.297, h-index: 7)
Advances in Power Electronics     Open Access   (Followers: 20, SJR: 0.26, h-index: 6)
Advances in Preventive Medicine     Open Access   (Followers: 6)
Advances in Public Health     Open Access   (Followers: 19)
Advances in Software Engineering     Open Access   (Followers: 10)
Advances in Tribology     Open Access   (Followers: 10, SJR: 0.267, h-index: 6)
Advances in Urology     Open Access   (Followers: 10, SJR: 0.629, h-index: 16)
Advances in Virology     Open Access   (Followers: 7, SJR: 1.04, h-index: 12)
AIDS Research and Treatment     Open Access   (Followers: 3, SJR: 1.125, h-index: 14)
Analytical Cellular Pathology     Open Access   (Followers: 1, SJR: 0.334, h-index: 12)
Anatomy Research Intl.     Open Access   (Followers: 1)
Anemia     Open Access   (Followers: 4, SJR: 0.991, h-index: 11)
Anesthesiology Research and Practice     Open Access   (Followers: 13, SJR: 0.513, h-index: 12)
Applied and Environmental Soil Science     Open Access   (Followers: 15, SJR: 0.53, h-index: 9)
Applied Bionics and Biomechanics     Open Access   (Followers: 8, SJR: 0.23, h-index: 13)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Archaea     Open Access   (Followers: 3, SJR: 1.248, h-index: 27)
Arthritis     Open Access   (Followers: 4)
Autism Research and Treatment     Open Access   (Followers: 29)
Autoimmune Diseases     Open Access   (Followers: 3, SJR: 0.909, h-index: 17)
Behavioural Neurology     Open Access   (Followers: 7, SJR: 0.696, h-index: 34)
Biochemistry Research Intl.     Open Access   (Followers: 6, SJR: 1.085, h-index: 17)
Bioinorganic Chemistry and Applications     Open Access   (Followers: 9, SJR: 0.286, h-index: 19)
BioMed Research Intl.     Open Access   (Followers: 6, SJR: 0.725, h-index: 59)
Biotechnology Research Intl.     Open Access   (Followers: 2)
Bone Marrow Research     Open Access   (Followers: 2)
Canadian J. of Gastroenterology & Hepatology     Open Access   (Followers: 3, SJR: 0.856, h-index: 53)
Canadian J. of Infectious Diseases and Medical Microbiology     Open Access   (Followers: 3, SJR: 0.409, h-index: 25)
Canadian Respiratory J.     Open Access   (Followers: 1, SJR: 0.503, h-index: 42)
Cardiology Research and Practice     Open Access   (Followers: 7, SJR: 0.941, h-index: 17)
Cardiovascular Psychiatry and Neurology     Open Access   (Followers: 4, SJR: 1.091, h-index: 14)
Case Reports in Anesthesiology     Open Access   (Followers: 10)
Case Reports in Cardiology     Open Access   (Followers: 2)
Case Reports in Critical Care     Open Access   (Followers: 8)
Case Reports in Dentistry     Open Access   (Followers: 3)
Case Reports in Dermatological Medicine     Open Access   (Followers: 2)
Case Reports in Emergency Medicine     Open Access   (Followers: 13)
Case Reports in Endocrinology     Open Access   (SJR: 0.326, h-index: 1)
Case Reports in Gastrointestinal Medicine     Open Access   (Followers: 3)
Case Reports in Genetics     Open Access   (Followers: 1)
Case Reports in Hematology     Open Access   (Followers: 2)
Case Reports in Hepatology     Open Access   (Followers: 1)
Case Reports in Immunology     Open Access   (Followers: 4)
Case Reports in Infectious Diseases     Open Access   (Followers: 5)
Case Reports in Medicine     Open Access   (Followers: 3)
Case Reports in Nephrology     Open Access   (Followers: 4)
Case Reports in Neurological Medicine     Open Access   (Followers: 1)
Case Reports in Obstetrics and Gynecology     Open Access   (Followers: 10)
Case Reports in Oncological Medicine     Open Access   (Followers: 2)
Case Reports in Ophthalmological Medicine     Open Access   (Followers: 2)
Case Reports in Orthopedics     Open Access   (Followers: 7)
Case Reports in Otolaryngology     Open Access   (Followers: 5)
Case Reports in Pathology     Open Access   (Followers: 3)
Case Reports in Pediatrics     Open Access   (Followers: 5)
Case Reports in Psychiatry     Open Access   (Followers: 10)
Case Reports in Pulmonology     Open Access   (Followers: 2)
Case Reports in Radiology     Open Access   (Followers: 8)
Case Reports in Rheumatology     Open Access   (Followers: 4)
Case Reports in Surgery     Open Access   (Followers: 7)
Case Reports in Transplantation     Open Access  
Case Reports in Urology     Open Access   (Followers: 8)
Case Reports in Vascular Medicine     Open Access  
Case Reports in Veterinary Medicine     Open Access   (Followers: 5)
Chemotherapy Research and Practice     Open Access   (Followers: 1)
Child Development Research     Open Access   (Followers: 13)
Chinese J. of Engineering     Open Access   (Followers: 2)
Chinese J. of Mathematics     Open Access  
Cholesterol     Open Access   (Followers: 1, SJR: 0.906, h-index: 12)
Chromatography Research Intl.     Open Access   (Followers: 7)
Computational and Mathematical Methods in Medicine     Open Access   (Followers: 2, SJR: 0.415, h-index: 22)
Computational Intelligence and Neuroscience     Open Access   (Followers: 9, SJR: 0.232, h-index: 30)
Critical Care Research and Practice     Open Access   (Followers: 9, SJR: 0.916, h-index: 14)
Current Gerontology and Geriatrics Research     Open Access   (Followers: 9, SJR: 0.8, h-index: 12)
Dataset Papers in Science     Open Access  
Depression Research and Treatment     Open Access   (Followers: 13, SJR: 0.77, h-index: 11)
Dermatology Research and Practice     Open Access   (Followers: 2, SJR: 0.576, h-index: 15)
Diagnostic and Therapeutic Endoscopy     Open Access   (SJR: 0.651, h-index: 18)
Discrete Dynamics in Nature and Society     Open Access   (Followers: 5, SJR: 0.323, h-index: 24)
Disease Markers     Open Access   (Followers: 1, SJR: 0.774, h-index: 49)
Economics Research Intl.     Open Access   (Followers: 2)
Education Research Intl.     Open Access   (Followers: 18)
Emergency Medicine Intl.     Open Access   (Followers: 6)
Enzyme Research     Open Access   (Followers: 4, SJR: 0.457, h-index: 18)
Epidemiology Research Intl.     Open Access   (Followers: 10)
Epilepsy Research and Treatment     Open Access   (Followers: 3)
Evidence-based Complementary and Alternative Medicine     Open Access   (Followers: 18, SJR: 0.615, h-index: 50)
Experimental Diabetes Research     Open Access   (Followers: 10, SJR: 1.591, h-index: 30)
Gastroenterology Research and Practice     Open Access   (Followers: 3, SJR: 0.664, h-index: 21)
Genetics Research Intl.     Open Access   (Followers: 1)
Hepatitis Research and Treatment     Open Access   (Followers: 6)
HPB Surgery     Open Access   (Followers: 5, SJR: 0.798, h-index: 22)
Indian J. of Materials Science     Open Access  
Infectious Diseases in Obstetrics and Gynecology     Open Access   (Followers: 7, SJR: 0.976, h-index: 34)
Influenza Research and Treatment     Open Access   (Followers: 2)
Interdisciplinary Perspectives on Infectious Diseases     Open Access   (Followers: 2, SJR: 0.763, h-index: 15)
Intl. J. of Aerospace Engineering     Open Access   (Followers: 65, SJR: 0.241, h-index: 6)
Intl. J. of Agronomy     Open Access   (Followers: 8, SJR: 0.223, h-index: 2)
Intl. J. of Alzheimer's Disease     Open Access   (Followers: 11, SJR: 1.193, h-index: 25)
Intl. J. of Analysis     Open Access  
Intl. J. of Analytical Chemistry     Open Access   (Followers: 21, SJR: 0.157, h-index: 2)
Intl. J. of Antennas and Propagation     Open Access   (Followers: 9, SJR: 0.385, h-index: 15)
Intl. J. of Atmospheric Sciences     Open Access   (Followers: 23)
Intl. J. of Bacteriology     Open Access  
Intl. J. of Biodiversity     Open Access   (Followers: 4)
Intl. J. of Biomaterials     Open Access   (Followers: 5, SJR: 0.485, h-index: 10)
Intl. J. of Biomedical Imaging     Open Access   (Followers: 5, SJR: 0.581, h-index: 23)
Intl. J. of Breast Cancer     Open Access   (Followers: 12)
Intl. J. of Carbohydrate Chemistry     Open Access   (Followers: 7)
Intl. J. of Cell Biology     Open Access   (Followers: 4, SJR: 2.658, h-index: 25)
Intl. J. of Chemical Engineering     Open Access   (Followers: 7, SJR: 0.361, h-index: 10)
Intl. J. of Chronic Diseases     Open Access   (Followers: 1)
Intl. J. of Combinatorics     Open Access   (Followers: 1)
Intl. J. of Computer Games Technology     Open Access   (Followers: 11, SJR: 0.213, h-index: 12)
Intl. J. of Corrosion     Open Access   (Followers: 10, SJR: 0.19, h-index: 7)
Intl. J. of Dentistry     Open Access   (Followers: 6, SJR: 0.558, h-index: 11)
Intl. J. of Differential Equations     Open Access   (Followers: 6, SJR: 0.363, h-index: 11)
Intl. J. of Digital Multimedia Broadcasting     Open Access   (Followers: 5, SJR: 0.144, h-index: 10)
Intl. J. of Ecology     Open Access   (Followers: 7, SJR: 0.8, h-index: 11)
Intl. J. of Electrochemistry     Open Access   (Followers: 6)
Intl. J. of Endocrinology     Open Access   (Followers: 3, SJR: 0.961, h-index: 24)
Intl. J. of Engineering Mathematics     Open Access   (Followers: 3)
Intl. J. of Evolutionary Biology     Open Access   (Followers: 9)
Intl. J. of Family Medicine     Open Access   (Followers: 2)
Intl. J. of Food Science     Open Access   (Followers: 3)
Intl. J. of Forestry Research     Open Access   (Followers: 4)
Intl. J. of Genomics     Open Access   (Followers: 2, SJR: 0.721, h-index: 7)
Intl. J. of Geophysics     Open Access   (Followers: 5, SJR: 0.416, h-index: 8)
Intl. J. of Hepatology     Open Access   (Followers: 3)
Intl. J. of Hypertension     Open Access   (Followers: 5, SJR: 0.823, h-index: 20)
Intl. J. of Inflammation     Open Access   (SJR: 0.876, h-index: 14)
Intl. J. of Inorganic Chemistry     Open Access   (Followers: 2)
Intl. J. of Manufacturing Engineering     Open Access   (Followers: 2)
Intl. J. of Mathematics and Mathematical Sciences     Open Access   (Followers: 3, SJR: 0.346, h-index: 27)
Intl. J. of Medicinal Chemistry     Open Access   (Followers: 6)
Intl. J. of Metals     Open Access   (Followers: 4)
Intl. J. of Microbiology     Open Access   (Followers: 5, SJR: 1.006, h-index: 18)
Intl. J. of Microwave Science and Technology     Open Access   (Followers: 4, SJR: 0.167, h-index: 5)
Intl. J. of Molecular Imaging     Open Access  
Intl. J. of Navigation and Observation     Open Access   (Followers: 19, SJR: 0.411, h-index: 7)
Intl. J. of Nephrology     Open Access   (Followers: 2, SJR: 0.926, h-index: 14)
Intl. J. of Oceanography     Open Access   (Followers: 8)
Intl. J. of Optics     Open Access   (Followers: 6, SJR: 0.262, h-index: 7)
Intl. J. of Otolaryngology     Open Access   (Followers: 1)
Intl. J. of Pediatrics     Open Access   (Followers: 4)
Intl. J. of Peptides     Open Access   (Followers: 4, SJR: 0.73, h-index: 16)
Intl. J. of Photoenergy     Open Access   (Followers: 2, SJR: 0.348, h-index: 28)
Intl. J. of Plant Genomics     Open Access   (Followers: 4, SJR: 1.578, h-index: 20)
Intl. J. of Polymer Science     Open Access   (Followers: 23, SJR: 0.265, h-index: 11)
Intl. J. of Population Research     Open Access   (Followers: 2)
Intl. J. of Proteomics     Open Access   (Followers: 1)
Intl. J. of Quality, Statistics, and Reliability     Open Access   (Followers: 13, SJR: 0.345, h-index: 4)
Intl. J. of Reconfigurable Computing     Open Access   (SJR: 0.182, h-index: 8)
Intl. J. of Reproductive Medicine     Open Access   (Followers: 5)
Intl. J. of Rheumatology     Open Access   (Followers: 4, SJR: 1.015, h-index: 18)
Intl. J. of Rotating Machinery     Open Access   (Followers: 2, SJR: 0.402, h-index: 19)
Intl. J. of Spectroscopy     Open Access   (Followers: 8)
Intl. J. of Stochastic Analysis     Open Access   (Followers: 4, SJR: 0.234, h-index: 19)
Intl. J. of Surgical Oncology     Open Access   (Followers: 1, SJR: 0.753, h-index: 11)
Intl. J. of Telemedicine and Applications     Open Access   (Followers: 3, SJR: 0.757, h-index: 14)
Intl. J. of Vascular Medicine     Open Access   (SJR: 0.865, h-index: 16)
Intl. J. of Vehicular Technology     Open Access   (Followers: 4, SJR: 0.169, h-index: 6)
Intl. J. of Zoology     Open Access   (Followers: 2, SJR: 0.389, h-index: 8)
Intl. Scholarly Research Notices     Open Access   (Followers: 199)
ISRN Astronomy and Astrophysics     Open Access   (Followers: 7)
J. of Addiction     Open Access   (Followers: 10)

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Journal Cover Advances in Astronomy
  [SJR: 0.351]   [H-I: 17]   [34 followers]  Follow
    
  This is an Open Access Journal Open Access journal
   ISSN (Print) 1687-7969 - ISSN (Online) 1687-7977
   Published by Hindawi Homepage  [334 journals]
  • The Observer’s Guide to the Gamma-Ray Burst Supernova Connection

    • Abstract: We present a detailed report of the connection between long-duration gamma-ray bursts (GRBs) and their accompanying supernovae (SNe). The discussion presented here places emphasis on how observations, and the modelling of observations, have constrained what we know about GRB-SNe. We discuss their photometric and spectroscopic properties, their role as cosmological probes, including their measured luminosity–decline relationships, and how they can be used to measure the Hubble constant. We present a statistical summary of their bolometric properties and use this to determine the properties of the “average” GRB-SN. We discuss their geometry and consider the various physical processes that are thought to power the luminosity of GRB-SNe and whether differences exist between GRB-SNe and the SNe associated with ultra-long-duration GRBs. We discuss how observations of their environments further constrain the physical properties of their progenitor stars and give a brief overview of the current theoretical paradigms of their central engines. We then present an overview of the radioactively powered transients that have been photometrically associated with short-duration GRBs, and we conclude by discussing what additional research is needed to further our understanding of GRB-SNe, in particular the role of binary-formation channels and the connection of GRB-SNe with superluminous SNe.
      PubDate: Tue, 11 Apr 2017 09:21:31 +000
       
  • Research on Control Method of Keeping Flight Formation by Using SDRE on
           the Sun-Earth Libration Points

    • Abstract: Keeping the flying formation of spacecraft is a key problem which needs to be solved in deep space exploration missions. In this paper, the nonlinear dynamic model of formation flying is established and a series of transformations are carried out on this model equation. By using SDRE (State-Dependent Riccati Equation) algorithm, the optimal control of flying formation is realized. Compared with the traditional control method based on the average orbit elements and LQR (Linear Quadratic Regulator) control method, the SDRE control method has higher control precision and is more suitable for the advantages of continuous control in practical engineering. Finally, the parameter values of the sun-earth libration point L2 are substituted in the equation and simulation is performed. The simulation curves of SDRE controller are compared with LQR controller. The results show that the SDRE controllers time cost is less than the LQR controllers and the former’s fuel consumption is less than the latter’s in the system transition process.
      PubDate: Mon, 13 Feb 2017 09:43:45 +000
       
  • Modeling Kelvin–Helmholtz Instability in Soft X-Ray Solar Jets

    • Abstract: Development of Kelvin–Helmholtz (KH) instability in solar coronal jets can trigger the wave turbulence considered as one of the main mechanisms of coronal heating. In this review, we have investigated the propagation of normal MHD modes running on three X-ray jets modeling them as untwisted and slightly twisted moving cylindrical flux tubes. The basic physical parameters of the jets are temperatures in the range of 5.2–8.2 MK, particle number densities of the order of  cm−3, and speeds of 385, 437, and 532 km s−1, respectively. For small density contrast between the environment and a given jet, as well as at ambient coronal temperature of 2.0 MK and magnetic field around 7 G, we have obtained that the kink () mode propagating on moving untwisted flux tubes can become unstable in the first and second jets at flow speeds of ≅348 and 429 km s−1, respectively. The KH instability onset in the third jet requires a speed of ≅826 km s−1, higher than the observed one. The same mode, propagating in weakly twisted flux tubes, becomes unstable at flow speeds of ≅361 km s−1 for the first and of 443 km s−1 for the second jet. Except the kink mode, the twisted moving flux tube supports the propagation of higher () MHD modes that can become unstable at accessible jets’ speeds.
      PubDate: Wed, 08 Feb 2017 00:00:00 +000
       
  • Astronomical Tasks for Tests of X-Ray Optics in VZLUSAT-1 Nanosatellite

    • Abstract: VZLUSAT-1 nanosatellite (scheduled launch in spring 2017 from India) is a CubeSat mission which, besides other instrumentation, contains X-ray desk to perform efficiency tests of the X-ray optics. In this article the analysis of potential observational candidates for VZLUSAT-1 X-ray board is presented together with the suggestion of observational modes, laboratory measurements, and estimations of exposure settings.
      PubDate: Tue, 07 Feb 2017 00:00:00 +000
       
  • Analysis of the Conformally Flat Approximation for Binary Neutron Star
           Initial Conditions

    • Abstract: The spatially conformally flat approximation (CFA) is a viable method to deduce initial conditions for the subsequent evolution of binary neutron stars employing the full Einstein equations. Here we analyze the viability of the CFA for the general relativistic hydrodynamic initial conditions of binary neutron stars. We illustrate the stability of the conformally flat condition on the hydrodynamics by numerically evolving ~100 quasicircular orbits. We illustrate the use of this approximation for orbiting neutron stars in the quasicircular orbit approximation to demonstrate the equation of state dependence of these initial conditions and how they might affect the emergent gravitational wave frequency as the stars approach the innermost stable circular orbit.
      PubDate: Mon, 09 Jan 2017 09:18:56 +000
       
  • High-Order Analytic Expansion of Disturbing Function for Doubly Averaged
           Circular Restricted Three-Body Problem

    • Abstract: Terms in the analytic expansion of the doubly averaged disturbing function for the circular restricted three-body problem using the Legendre polynomial are explicitly calculated up to the fourteenth order of semimajor axis ratio between perturbed and perturbing bodies in the inner case , and up to the fifteenth order in the outer case . The expansion outcome is compared with results from numerical quadrature on an equipotential surface. Comparison with direct numerical integration of equations of motion is also presented. Overall, the high-order analytic expansion of the doubly averaged disturbing function yields a result that agrees well with the numerical quadrature and with the numerical integration. Local extremums of the doubly averaged disturbing function are quantitatively reproduced by the high-order analytic expansion even when is large. Although the analytic expansion is not applicable in some circumstances such as when orbits of perturbed and perturbing bodies cross or when strong mean motion resonance is at work, our expansion result will be useful for analytically understanding the long-term dynamical behavior of perturbed bodies in circular restricted three-body systems.
      PubDate: Tue, 06 Dec 2016 12:59:28 +000
       
  • Gamma-Ray Bursts: A Radio Perspective

    • Abstract: Gamma-ray bursts (GRBs) are extremely energetic events at cosmological distances. They provide unique laboratory to investigate fundamental physical processes under extreme conditions. Due to extreme luminosities, GRBs are detectable at very high redshifts and potential tracers of cosmic star formation rate at early epoch. While the launch of Swift and Fermi has increased our understanding of GRBs tremendously, many new questions have opened up. Radio observations of GRBs uniquely probe the energetics and environments of the explosion. However, currently only 30% of the bursts are detected in radio bands. Radio observations with upcoming sensitive telescopes will potentially increase the sample size significantly and allow one to follow the individual bursts for a much longer duration and be able to answer some of the important issues related to true calorimetry, reverse shock emission, and environments around the massive stars exploding as GRBs in the early Universe.
      PubDate: Wed, 23 Nov 2016 13:37:12 +000
       
  • Effective Perihelion Advance and Potentials in a Conformastatic Background
           with Magnetic Field

    • Abstract: Exact solutions of the Einstein-Maxwell field equations for a conformastatic metric with magnetized sources are investigated. In this context, effective potentials are studied in order to understand the dynamics of the magnetic field in galaxies. We derive the equations of motion for neutral and charged particles in a spacetime background characterized by this class of solutions. In this particular case, we investigate the main physical properties of the equatorial circular orbits and related effective potentials. In addition, we obtain an effective analytic expression for the perihelion advance of test particles. Our theoretical predictions are compared with the observational data calibrated with the ephemerides of the planets of the solar system and the Moon (EPM2011). In general, we show that the magnetic punctual mass predicts values that are in better agreement with observations than the values predicted in Einstein’s gravity alone.
      PubDate: Sun, 20 Nov 2016 14:10:20 +000
       
  • Intelligent Cognitive Radio Models for Enhancing Future Radio Astronomy
           Observations

    • Abstract: Radio astronomy organisations desire to optimise the terrestrial radio astronomy observations by mitigating against interference and enhancing angular resolution. Ground telescopes (GTs) experience interference from intersatellite links (ISLs). Astronomy source radio signals received by GTs are analysed at the high performance computing (HPC) infrastructure. Furthermore, observation limitation conditions prevent GTs from conducting radio astronomy observations all the time, thereby causing low HPC utilisation. This paper proposes mechanisms that protect GTs from ISL interference without permanent prevention of ISL data transmission and enhance angular resolution. The ISL transmits data by taking advantage of similarities in the sequence of observed astronomy sources to increase ISL connection duration. In addition, the paper proposes a mechanism that enhances angular resolution by using reconfigurable earth stations. Furthermore, the paper presents the opportunistic computing scheme (OCS) to enhance HPC utilisation. OCS enables the underutilised HPC to be used to train learning algorithms of a cognitive base station. The performances of the three mechanisms are evaluated. Simulations show that the proposed mechanisms protect GTs from ISL interference, enhance angular resolution, and improve HPC utilisation.
      PubDate: Mon, 17 Oct 2016 14:29:12 +000
       
  • A Decade of GRB Follow-Up by BOOTES in Spain (2003–2013)

    • Abstract: This article covers ten years of GRB follow-ups by the Spanish BOOTES stations: 71 follow-ups providing 23 detections. Follow-ups by BOOTES-1B from 2005 to 2008 were given in a previous article and are here reviewed and updated, and additional detection data points are included as the former article merely stated their existence. The all-sky cameras CASSANDRA have not yet detected any GRB optical afterglows, but limits are reported where available.
      PubDate: Mon, 10 Oct 2016 13:15:44 +000
       
  • Analytic Models of Brown Dwarfs and the Substellar Mass Limit

    • Abstract: We present the analytic theory of brown dwarf evolution and the lower mass limit of the hydrogen burning main-sequence stars and introduce some modifications to the existing models. We give an exact expression for the pressure of an ideal nonrelativistic Fermi gas at a finite temperature, therefore allowing for nonzero values of the degeneracy parameter. We review the derivation of surface luminosity using an entropy matching condition and the first-order phase transition between the molecular hydrogen in the outer envelope and the partially ionized hydrogen in the inner region. We also discuss the results of modern simulations of the plasma phase transition, which illustrate the uncertainties in determining its critical temperature. Based on the existing models and with some simple modification, we find the maximum mass for a brown dwarf to be in the range . An analytic formula for the luminosity evolution allows us to estimate the time period of the nonsteady state (i.e., non-main-sequence) nuclear burning for substellar objects. We also calculate the evolution of very low mass stars. We estimate that ≃11% of stars take longer than  yr to reach the main sequence, and ≃5% of stars take longer than  yr.
      PubDate: Mon, 10 Oct 2016 07:46:30 +000
       
  • Space Creation Mechanism during the Expansion of Universe

    • Abstract: We propose a novel mechanism related to the expansion of universe. Recently Verlinde’s proposal has been applied to the deformed bosons being a candidate for the dark energy constituents, since the negative pressure of the deformed bosons. The expansion of universe is dependent on the dark energy and implies a creation of space; we admit that the space creation mechanism is related to the deformed bosons and so is the dark energy. In order to relate the dark energy and the mechanism for creation of space, we consider Verlinde’s proposal including the Holographic principle for emergence of space, which was recently applied to the deformed bosons. To check the validity of our mechanism, we calculate the ratio of the size of universe before and after the expansion and compare the results with the observational data. We find that the results are consistent with each other and infer that the proposed mechanism works correctly.
      PubDate: Wed, 28 Sep 2016 07:50:45 +000
       
  • Atmospheric Effect on Cosmic Ray Muons at High Cut-Off Rigidity Station

    • Abstract: Cosmic ray data and radiosonde measurements from Riyadh, Saudi Arabia (Rc = 14.4 GV), for the period 2002–2012, were used to study the effect of atmospheric pressure, level of pion production, and temperature at that level, on cosmic ray muons. We found that, even if corrections were made to the detected muons using these three parameters, seasonal variations of the cosmic rays still exist. This suggests that other terrestrial and/or extraterrestrial causes may be considered. The levels of pion production and atmospheric pressure are inversely correlated with the muon rate. On the other hand, the temperature at the pion production level is correlated with muons in spring and winter and inversely correlated in fall and summer. There is no clear explanation for this behavior.
      PubDate: Thu, 25 Aug 2016 09:44:26 +000
       
  • Caravan-Submm, Black Hole Imager in the Andes

    • Abstract: Imaging a black hole horizon as a shadow at the center of black hole accretion disk is another method to prove/check Einstein’s general relativity at strong gravitational fields. Such black hole imaging is expected to be achievable using a submillimeter wavelength VLBI (very long baseline interferometer) technique. Here, we introduce a Japanese black hole imaging project, Caravan-submm undertaken in the Andes.
      PubDate: Wed, 20 Jul 2016 10:05:04 +000
       
  • Kilonova/Macronova Emission from Compact Binary Mergers

    • Abstract: We review current understanding of kilonova/macronova emission from compact binary mergers (mergers of two neutron stars or a neutron star and a black hole). Kilonova/macronova is emission powered by radioactive decays of -process nuclei and it is one of the most promising electromagnetic counterparts of gravitational wave sources. Emission from the dynamical ejecta of ~0.01 is likely to have a luminosity of ~1040–1041 erg s−1 with a characteristic timescale of about 1 week. The spectral peak is located in red optical or near-infrared wavelengths. A subsequent accretion disk wind may provide an additional luminosity or an earlier/bluer emission if it is not absorbed by the precedent dynamical ejecta. The detection of near-infrared excess in short GRB 130603B and possible optical excess in GRB 060614 supports the concept of the kilonova/macronova scenario. At 200 Mpc distance, a typical peak brightness of kilonova/macronova with ejecta is about 22 mag and the emission rapidly fades to >24 mag within ~10 days. Kilonova/macronova candidates can be distinguished from supernovae by (1) the faster time evolution, (2) fainter absolute magnitudes, and (3) redder colors. Since the high expansion velocity () is a robust outcome of compact binary mergers, the detection of smooth spectra will be the smoking gun to conclusively identify the gravitational wave source.
      PubDate: Thu, 14 Jul 2016 07:15:28 +000
       
  • The Photometric Investigation of V921 Her Using the Lunar-Based
           Ultraviolet Telescope of Chang’e-3 Mission

    • Abstract: The light curve of V921 Her in ultraviolet band observed by the Lunar-based Ultraviolet Telescope (LUT) is analyzed by the Wilson-Devinney code. Our solutions conclude that V921 Her is an early type marginal contact binary system with an additional close-in component. The binary system is under poor thermal contact with a temperature difference of nearly 700 K between the two components. The close-in component contributes about 19% of the total luminosity in the triple system. Combining the radial velocity study together with our photometric solutions, the mass of the primary star and secondary one is calculated to be , . The evolutionary scenario of V921 Her is discussed. All times of light minimum of V921 Her available in the bibliography are taken into account and the curve is analyzed for the first time. The most probable fitting results are discussed in the paper, which also confirm the existence of a third component ( year) around the binary system. The period of V921 Her is also undergoing a continuously rapid increase at a rate of , which may be due to mass transfer from the less massive component to the more massive one.
      PubDate: Wed, 15 Jun 2016 09:26:11 +000
       
  • A Time-Dependent and Cosmological Model Consistent with Cosmological
           Constraints

    • Abstract: The prevailing constant cosmological model agrees with observational evidence including the observed red shift, Big Bang Nucleosynthesis (BBN), and the current rate of acceleration. It assumes that matter contributes 27% to the current density of the universe, with the rest (73%) coming from dark energy represented by the Einstein cosmological parameter in the governing Friedmann-Robertson-Walker equations, derived from Einstein’s equations of general relativity. However, the principal problem is the extremely small value of the cosmological parameter (~10−52 m2). Moreover, the dark energy density represented by is presumed to have remained unchanged as the universe expanded by 26 orders of magnitude. Attempts to overcome this deficiency often invoke a variable model. Cosmic constraints from action principles require that either both and remain time-invariant or both vary in time. Here, we propose a variable cosmological model consistent with the latest red shift data, the current acceleration rate, and BBN, provided the split between matter and dark energy is 18% and 82%. decreases (, where is the normalized cosmic time) and increases () with cosmic time. The model results depend only on the chosen value of at present and in the far future and not directly on .
      PubDate: Wed, 08 Jun 2016 09:19:53 +000
       
  • Diverse Features of the Multiwavelength Afterglows of Gamma-Ray Bursts:
           Natural or Special?

    • Abstract: The detection of optical rebrightenings and X-ray plateaus in the afterglows of gamma-ray bursts (GRBs) challenges the generic external shock model. Recently, we have developed a numerical method to calculate the dynamics of the system consisting of a forward shock and a reverse shock. Here, we briefly review the applications of this method in the afterglow theory. By relating these diverse features to the central engines of GRBs, we find that the steep optical rebrightenings would be caused by the fall-back accretion of black holes, while the shallow optical rebrightenings are the consequence of the injection of the electron-positron-pair wind from the central magnetar. These studies provide useful ways to probe the characteristics of GRB central engines.
      PubDate: Sun, 15 May 2016 08:22:39 +000
       
  • Adjacent Zero Communication Parallel Cloud Computing Method and Its System
           for -Body Problem with Short-Range Interaction Domain Decomposition

    • Abstract: Although parallel computing is used in the existing numerical solutions of -body problem, tons of communications between particles render the parallel efficiency extremely low. Despite the fact that domain decomposition based on short-range interaction is used, when is exceedingly large and lots of communications exist between particles in adjacent areas, the parallel efficiency remains terribly low. This paper puts forward adjacent zero communication parallel cloud computing method for -body problem with short-range interaction domain decomposition. According to this method, the adjacent subblock data are exchanged and redundantly stored without acquiring data from other subblocks in the parallel processing, so the waiting time for data transmission can be saved and hence the parallel processing efficiency can be enhanced substantially.
      PubDate: Mon, 21 Mar 2016 10:45:29 +000
       
  • Physical Environment of Accreting Neutron Stars

    • Abstract: Neutron stars (NSs) powered by accretion, which are known as accretion-powered NSs, always are located in binary systems and manifest themselves as X-ray sources. Physical processes taking place during the accretion of material from their companions form a challenging and appealing topic, because of the strong magnetic field of NSs. In this paper, we review the physical process of accretion onto magnetized NS in X-ray binary systems. We, firstly, give an introduction to accretion-powered NSs and review the accretion mechanism in X-ray binaries. This review is mostly focused on accretion-induced evolution of NSs, which includes scenario of NSs both in high-mass binaries and in low-mass systems.
      PubDate: Mon, 21 Mar 2016 09:17:36 +000
       
  • Realization of High Dynamic Range Imaging in the GLORIA Network and Its
           Effect on Astronomical Measurement

    • Abstract: Citizen science project GLORIA (GLObal Robotic-telescopes Intelligent Array) is a first free- and open-access network of robotic telescopes in the world. It provides a web-based environment where users can do research in astronomy by observing with robotic telescopes and/or by analyzing data that other users have acquired with GLORIA or from other free-access databases. Network of 17 telescopes allows users to control selected telescopes in real time or schedule any more demanding observation. This paper deals with new opportunity that GLORIA project provides to teachers and students of various levels of education. At the moment, there are prepared educational materials related to events like Sun eclipse (measuring local atmosphere changes), Aurora Borealis (calculation of Northern Lights height), or transit of Venus (measurement of the Earth-Sun distance). Student should be able to learn principles of CCD imaging, spectral analysis, basic calibration like dark frames subtraction, or advanced methods of noise suppression. Every user of the network can design his own experiment. We propose advanced experiment aimed at obtaining astronomical image data with high dynamic range. We also introduce methods of objective image quality evaluation in order to discover how HDR methods are affecting astronomical measurements.
      PubDate: Sun, 13 Mar 2016 13:51:32 +000
       
  • Planar Central Configurations of Symmetric Five-Body Problems with Two
           Pairs of Equal Masses

    • Abstract: We study central configuration of a set of symmetric planar five-body problems where the five masses are arranged in such a way that , , and are collinear and , , and are collinear; the two sets of collinear masses form a triangle with at the intersection of the two sets of collinear masses; four of the bodies are on the vertices of an isosceles trapezoid and the fifth body can take various positions on the axis of symmetry both outside and inside the trapezoid. We form expressions for mass ratios and identify regions in the phase space where it is possible to choose positive masses which will make the configuration central. We also show that the triangular configuration is not possible.
      PubDate: Tue, 08 Mar 2016 09:38:19 +000
       
  • A Hydrodynamical Model of a Rotating Wind Source and Its Effects on the
           Collapse of a Rotating Core

    • Abstract: This work presents three-dimensional hydrodynamical simulations with the fully parallel GAGDET2 code, to model a rotating source that emits wind in order to study the subsequent dynamics of the wind in three independent scenarios. In the first scenario we consider several models of the wind source, which is characterized by a rotation velocity and an escape velocity , so that the models have a radially outward wind velocity magnitude given by 1, 2, 4, 6, and 8 times . In the second scenario, we study the interaction of winds emitted from a binary system in two kinds of models: one in which the source remains during the wind emission and a second one in which all the source itself becomes wind. In the third scenario we consider the interaction of a rotating source that emits wind within a collapsing and rotating core. In this scenario we consider only wind models of the second kind built over a new initial radial mesh, such that the angular velocity of the wind is 1, 100, and 1000 times the angular velocity of the core .
      PubDate: Sun, 27 Dec 2015 11:54:16 +000
       
  • The Impact of KLT Coder on the Image Distortion in Astronomy

    • Abstract: Presented paper is devoted to the application of Karhunen-Loève transform (KLT) for compression and to study of KLT impact on the image distortion in astronomy. This transform is an optimal fit for images with Gaussian probability density function in order to minimize the root mean square error (RMSE). The main part of the encoder is proposed in relation to statistical image properties. Selected astronomical image processing algorithms are used for the encoder testing. The astrometry and point spread function distortion are selected as the most important criteria. The results are compared with JPEG2000 standard. The KLT encoder provides better results from the RMSE point of view. These results are promising and show the novel approach to the design of lossy image compression algorithms and also suitability for algorithms of image data structuring for retrieving, transfer, and distribution.
      PubDate: Tue, 24 Nov 2015 09:27:49 +000
       
  • Parameterizing the SFC Baryogenesis Model

    • Abstract: We have numerically explored the scalar field condensate baryogenesis model for numerous sets of model’s parameters, within their natural range of values. We have investigated the evolution of the baryon charge carrying field, the evolution of the baryon charge contained in the scalar field condensate, and the final value of the generated baryon charge on the model’s parameters: the gauge coupling constant , the Hubble constant at the inflationary stage , the mass , and the self-coupling constants .
      PubDate: Tue, 15 Sep 2015 10:40:06 +000
       
  • Corrigendum to “Regions of Central Configurations in a Symmetric 4
           + 1-Body Problem”

    • PubDate: Sun, 13 Sep 2015 13:52:55 +000
       
  • The Appearance and Disappearance of Exocomet Gas Absorption

    • Abstract: CaII K-line (3933 Å) absorption profiles observed towards 15 A-type and two B-type stars with known (or suspected) debris disks, in addition to archival spectral data for three A-type stars, are presented. Inspection of the extracted CaII K-line absorption lines has determined that one late B-type (HD 58647) and four new A-type (HD 56537, HD 64145, HD 108767, and HD 109573) stellar systems exhibit short-term (night-to-night) absorption variation within these profiles. This variability is due to the liberation of gas from falling evaporating bodies (the so-called FEBs activity) on the grazing approach of exocomets towards their parent star. Also we present archival spectra of the FeI λ3860 Å and CaII K-lines towards β Pictoris (HD 39060) that, for the first time, reveal the absorption signatures of FEB activity at similar velocities in both line profiles. FEB-hosting stars seem to be of an earlier type (on average spectral type Al.8 as compared with A3.1) than those where no FEB activity has been observed. This could be due to stellar activity levels (such as chromospheric activity or nonradial pulsations) being of a higher level within the atmospheres of these hotter A-type stars.
      PubDate: Sun, 13 Sep 2015 09:02:13 +000
       
  • Cosmic Rays Report from the Structure of Space

    • Abstract: Spectrum of cosmic rays follows a broken power law over twelve orders of magnitude. Since ubiquitous power laws are manifestations of the principle of least action, we interpret the spectrum accordingly. Our analysis complies with understanding that low-energy particles originate mostly from rapidly receding sources throughout the cosmos. The flux peaks about proton rest energy whereafter it decreases because fewer and fewer receding sources are energetic enough to provide particles with high enough velocities to compensate for the recessional velocities. Above 1015.6 eV the flux from the expanding Universe diminishes below the flux from the nearby nonexpanding part of the Universe. In this spectral feature, known as the “knee,” we relate to a distance of about 1.3 Mpc where the gravitational potential tallies the energy density of free space. At higher energies particles decelerate in a dissipative manner to attain thermodynamic balance with the vacuum. At about 1017.2 eV a distinct dissipative mechanism opens up for protons to slow down by electron-positron pair production. At about 1019.6 eV a more effective mechanism opens up via pion production. All in all, the universal principle discloses that the broad spectrum of cosmic rays probes the structure of space from cosmic distances down to microscopic details.
      PubDate: Sun, 06 Sep 2015 13:57:49 +000
       
  • An Improved Infrared/Visible Fusion for Astronomical Images

    • Abstract: An undecimated dual tree complex wavelet transform (UDTCWT) based fusion scheme for astronomical visible/IR images is developed. The UDTCWT reduces noise effects and improves object classification due to its inherited shift invariance property. Local standard deviation and distance transforms are used to extract useful information (especially small objects). Simulation results compared with the state-of-the-art fusion techniques illustrate the superiority of proposed scheme in terms of accuracy for most of the cases.
      PubDate: Wed, 26 Aug 2015 09:34:34 +000
       
  • On the Stability of in the Relativistic R3BP with Oblate Secondary and
           Radiating Primary

    • Abstract: We consider a version of the relativistic restricted three-body problem (R3BP) which includes the effects of oblateness of the secondary and radiation of the primary. We determine the positions and analyze the stability of the triangular points. We find that these positions are affected by relativistic, oblateness, and radiation factors. It is also seen that both oblateness of the secondary and radiation of the primary reduce the size of stability region. Further, a numerical exploration computing the positions of the triangular points and the critical mass ratio of some binaries systems consisting of the Sun and its planets is given in the tables.
      PubDate: Tue, 25 Aug 2015 10:00:47 +000
       
 
 
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