112,618 research outputs found
Theoretical planetary mass spectra - a predition for COROT
The satellite COROT will search for close-in exo-planets around a few
thousand stars using the transit search method. The COROT mission holds the
promise of detecting numerous exo-planets. Together with radial velocity
follow-up observations, the masses of the detected planets will be known.
We have devised a method for predicting the expected planetary populations
and compared it to the already known exo-planets. Our method works by looking
at all hydrostatic envelope solutions of giant gas planets that could possibly
exist in arbitrary planetary nebulae and comparing the relative abundance of
different masses. We have completed the first such survey of hydrostatic
equilibria in an orbital range covering periods of 1 to 50 days.
Statistical analysis of the calculated envelopes suggests division into three
classes of giant planets that are distinguished by orbital separation. We term
them classes G (close-in), H, and J (large separation). Each class has distinct
properties such as a typical mass range.
Furthermore, the division between class H and J appears to mark important
changes in the formation: For close-in planets (classes G and H) the concept of
a critical core-mass is meaningless while it is important for class J. This
result needs confirmation by future dynamical analysis.Comment: 6 pages, 3 figures, MNRAS letter, accepted 2007 February
Relativistic quantum motion of spin-0 particles under the influence of non-inertial effects in the cosmic string space-time
We study solutions for the Klein-Gordon equation with vector and scalar
potentials of the Coulomb types under the influence of non-inertial effects in
the space-time of topological defects. We also investigate a quantum particle
described by the Klein-Gordon oscillator in the background space-time generated
by a string. An important result obtained is that the non-inertial effects
restrict the physical region of the space-time where the particle can be
placed. In addition, we show that these potentials can form bound states for
the relativistic wave equation equation in this kind of background.Comment: arXiv admin note: text overlap with arXiv:1608.0669
Klein-Gordon oscillator in a topologically nontrivial space-time
In this study, we analyze solutions of the wave equation for scalar particles
in a space-time with nontrivial topology. Solutions for the Klein--Gordon
oscillator are found considering two configurations of this space-time. In the
first one, it is assumed the space where the metric is
written in the usual inertial frame of reference. In the second case, we
consider a rotating reference frame adapted to the circle S1. We obtained
compact expressions for the energy spectrum and for the particles wave
functions in both configurations. Additionally, we show that the energy
spectrum of the solution associated to the rotating system has an additional
term that breaks the symmetry around
Social Entrepreneurship That Truly Benefits the Poor: An Integrative Justice Approach
The phenomenal growth of social entrepreneurship over thelast decade has ably demonstrated how technology, innovation, and anentrepreneurial spirit can afford better solutions to the vexing social andenvironmental problems of our time than can traditional aid and charitybasedefforts. In most cases, but not always, the poor and disadvantagedhave benefited from the growth of social entrepreneurship. In order toensure that social entrepreneurship does indeed benefit the poor, it isimperative that there be normative guidelines for fair and just engagementwith impoverished populations. A model that has been presented in themarketing and public policy literature is the integrative justice model (IJM)for impoverished populations. While the IJM was developed primarily in thecontext of multinational corporations (MNCs) operating in emerging markets,its applicability extends beyond MNCs. This article attempts to apply theIJM principles in the context of social entrepreneurship in order to providesocial entrepreneurial organizations (SEOs) with a normative frameworkaimed at ensuring that the poor truly benefit from their activities. Basedon this framework, the article suggests certain areas to which SEOs oughtto be particularly attentive in their practice. The article also makes somesuggestions for further research
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