90 research outputs found
Svestka's Research: Then and Now
Zdenek Svestka's research work influenced many fields of solar physics,
especially in the area of flare research. In this article I take five of the
areas that particularly interested him and assess them in a "then and now"
style. His insights in each case were quite sound, although of course in the
modern era we have learned things that he could not readily have envisioned.
His own views about his research life have been published recently in this
journal, to which he contributed so much, and his memoir contains much
additional scientific and personal information (Svestka, 2010).Comment: Invited review for "Solar and Stellar Flares," a conference in honour
of Prof. Zden\v{e}k \v{S}vestka, Prague, June 23-27, 2014. This is a
contribution to a Topical Issue in Solar Physics, based on the presentations
at this meeting (Editors Lyndsay Fletcher and Petr Heinzel
Acceptance and Use of E-Learning Based on Cloud Computing: The Role of Consumer Innovativeness
Cloud computing and E-learning are the inevitable trend of computational science in general, and information systems and technologies in specific.However, there are not many studies on the adoption of cloud-based E-learning systems. Moreover, while there are many papers on information system adoption as well as customer innovativeness, the innovativeness and adoption in the same model seems to be rare in the literature. The study combines the extended
Unified Theory of Acceptance and Use of Technology (UTAUT2) and consumer innovativeness on the adoption of E-learning systems based on cloud computing. A survey was conducted among 282 cloud-based E-learning participants and analyzed by structural equation modeling (SEM). The findings indicate that the adoption of cloud-based E-learning is influenced by performance expectancy, social influence, hedonic motivation, and habit. Interestingly, although innovativeness is not significant to use intention, it has a positive effect on E-learning usage which is relatively new in Vietnam
Distribution and composition of Mg-calcite and dolomite in the water and sediments of Lake Balaton
Gravitational Collapse and Disk Formation in Magnetized Cores
We discuss the effects of the magnetic field observed in molecular clouds on
the process of star formation, concentrating on the phase of gravitational
collapse of low-mass dense cores, cradles of sunlike stars. We summarize recent
analytic work and numerical simulations showing that a substantial level of
magnetic field diffusion at high densities has to occur in order to form
rotationally supported disks. Furthermore, newly formed accretion disks are
threaded by the magnetic field dragged from the parent core during the
gravitational collapse. These disks are expected to rotate with a sub-Keplerian
speed because they are partially supported by magnetic tension against the
gravity of the central star. We discuss how sub-Keplerian rotation makes it
difficult to eject disk winds and accelerates the process of planet migration.
Moreover, magnetic fields modify the Toomre criterion for gravitational
instability via two opposing effects: magnetic tension and pressure increase
the disk local stability, but sub-Keplerian rotation makes the disk more
unstable. In general, magnetized disks are more stable than their nonmagnetic
counterparts; thus, they can be more massive and less prone to the formation of
giant planets by gravitational instability.Comment: Chapter 16 in "Magnetic Fields in Diffuse Media", Springer-Verlag,
eds. de Gouveia Dal Pino, E., Lazarian, A., Melioli,
Linking environmental cancer with occupational epidemiology research: the role of the International Agency for Research on Cancer (IARC)
Linking environmental cancer with occupational epidemiology research: the role of the International Agency for Research on Cancer (IARC)
Kinetics and locus of failure of receptor-ligand-mediated adhesion between latex spheres. I. Protein-carbohydrate bond
Kinetics and locus of failure of receptor-ligand-mediated adhesion between latex spheres. II. Protein-protein bond
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