4,590 research outputs found
The role of the Krauss\u2019s organ in sound production in Pamphagidae (Caelifera: Orthoptera).
In Pamphagidae, the Krauss\u2019s organ is located on both sides of the 2nd tergite and its function is superficially known. It has been proposed to have a stridulatory function. This organ can be found in all Pamphagidae except the apterous genera. Rearing specimens of some species and observing mounted pamphagids allowed the author to observe that when the Krauss\u2019s organ is absent (most apterous species) the tympanum is also absent; further, he discovered specialized stridulatory structures on hind femurs of some taxa for sound emission. By rearing two Pamphagidae belonging to different genera, fragments of stridulations involving the Krauss\u2019s organ and specialized structures on the hind femur surface were obtained for the first time. Mapping the presence of these morphological characters onto the known Pamphagidae list revealed that specialization on the hind femur surface evolved multiple times in multiple geographical locations in winged species with a wrinkled Krauss\u2019s organ. The function of the sounds produced by the femur-Krauss\u2019s organ method remains to be studied
Smith on Krauss, \u27The Physics of Star Trek\u27
Review of Lawrence M. Krauss.The Physics of Star Trek. New York: Basic Books, 1995. xvi + 188 pp. $20.00(cloth), ISBN 978-0-465-00559-8.
Reviewed by Anne Collins Smith (Austin Community College) Published on H-PCAACA (May, 1996
Dynamics of WIMPs in the solar system and implications for direct and indirect detection
Semi-analytic treatments of the evolution of orbits of weakly interacting
massive particles (WIMPs) in the solar system suggest that the WIMPs bound to
the solar system may enhance the direct detection rate relative to that of the
unbound population by up to a factor of order unity, and boost the flux of
neutrinos from WIMP annihilation in the Earth by up to two orders of magnitude.
To test these important but uncertain results, we perform a suite of numerical
orbit integrations to explore the properties of the bound WIMP population as a
function of the WIMP mass and the scattering cross section with baryonic
matter. For regions of WIMP parameter space presently allowed by experiments,
we find that (i) the bound WIMP population enhances the direct detection rate
by at most ~1% relative to the rate from unbound halo WIMPs; (ii) it is
unlikely that planned km^3-scale neutrino telescopes will detect neutrinos from
WIMP annihilation in the Earth; (iii) the event rate from neutrinos produced by
WIMP annihilation in the Sun may be much smaller than implied by the usual
calculations, which assume that WIMPs scattered onto bound orbits are rapidly
thermalized in the Sun.Comment: 4 pages, 1 figure, to appear in the IDM2008 conference proceeding
Book Review of 'Breaking the surface : an art/archaeology of prehistoric architecture' by Douglass Bailey
DFT Calculations as a Tool to Analyse Quadrupole Splittings of Spin Crossover Fe(II) complexes
Density functional methods have been applied to calculate the quadrupole
splitting of a series of iron(II) spin crossover complexes. Experimental and
calculated values are in reasonable agreement. In one case spin-orbit coupling
is necessary to explain the very small quadrupole splitting value of 0.77 mm/s
at 293 K for a high-spin isomer
The Spectroscopic Age of 47 Tuc
High signal-to-noise integrated spectra of the metal-rich globular cluster 47
Tuc, spanning the H-gamma(HR) and Fe4668 line indices, have been obtained. The
combination of these indices has been suggested (Jones & Worthey 1995, ApJ,
446, L31) as the best available mechanism for cleanly separating the
age-metallicity degeneracy which hampers the dating of distant, unresolved,
elliptical galaxies. For the first time, we apply this technique to a nearby
spheroidal system, 47 Tuc, for which independent ages, based upon more
established methods, exist. Such an independent test of the technique's
suitability has not been attempted before, but is an essential one before its
application to more distant, unresolved, stellar populations can be considered
valid. Because of its weak series of Balmer lines, relative to model spectra,
our results imply a spectroscopic ``age'' for 47 Tuc well in excess of 20 Gyr,
at odds with the colour-magnitude diagram age of 14+/-1 Gyr. The derived metal
abundance, however, is consistent with the known value. Emission ``fill-in'' of
the H-gamma line as the source of the discrepancy cannot be entirely excluded
by existing data, although the observational constraints are restrictive.Comment: 17 pages, 4 figures, LaTeX, accepted for publication in The
Astronomical Journal, also available at
http://casa.colorado.edu/~bgibson/publications.htm
- …