627 research outputs found
Report on the Twelfth United Nations/European Space Agency Workshop on Basic Space Science
Pursuant to recommendations of the United Nations Conference on the
Exploration and Peaceful Uses of Outer Space (UNISPACE III) and deliberations
of the United Nations Committee on the Peaceful Uses of Outer Space (UNCOPUOS),
annual UN/European Space Agency workshops on basic space science have been held
around the world since 1991. These workshops contributed to the development of
astrophysics and space science, particularly in developing nations. Following a
process of prioritization, the workshops identified the following elements as
particularly important for international cooperation in the field: (i)
operation of astronomical telescope facilities implementing TRIPOD, (ii)
virtual observatories, (iii) astrophysical data systems, (iv) concurrent design
capabilities for the development of international space missions, and (v)
theoretical astrophysics such as applications of nonextensive statistical
mechanics. Beginning in 2005, the workshops focus on preparations for the
International Heliophysical Year 2007 (IHY2007). The workshops continue to
facilitate the establishment of astronomical telescope facilities as pursued by
Japan and the development of low-cost, ground-based, world-wide instrument
arrays as lead by the IHY secretariat.Comment: PDF, 9 page
Analytical results connecting stellar structure parameters and extended reaction rates
Possible modification in the velocity distribution in the non-resonant
reaction rates leads to an extended reaction rate probability integral. The
closed form representation for these thermonuclear functions are used to obtain
the stellar luminosity and neutrino emission rates. The composite parameter {C}
that determines the standard nuclear reaction rate through the
Maxwell-Boltzmann energy distribution is extended to {C}^* by the extended
reaction rates through a more general distribution than the Maxwell-Boltzmann
distribution. The new distribution is obtained by the pathway model introduced
by Mathai in 2005 [Linear Algebra and Its Applications, 396, 317-328]. Simple
analytic models considered by various authors are utilized for evaluating
stellar luminosity and neutrino emission rates and are obtained in generalized
special functions such as Meijer's G-function and Fox's H-function. The
standard and extended non-resonant thermonuclear functions are compared by
plotting them. Behavior of the new energy distribution, more general than
Maxwell-Boltzmann is also studied.Comment: 20 pages, LaTe
Stochastic processes via the pathway model
After collecting data from observations or experiments, the next step is to
build an appropriate mathematical or stochastic model to describe the data so
that further studies can be done with the help of the models. In this article,
the input-output type mechanism is considered first, where reaction, diffusion,
reaction-diffusion, and production-destruction type physical situations can fit
in. Then techniques are described to produce thicker or thinner tails (power
law behavior) in stochastic models. Then the pathway idea is described where
one can switch to different functional forms of the probability density
function) through a parameter called the pathway parameter.Comment: 15 pages, 7 figures, LaTe
- …