2,847 research outputs found
Prevalence, intensity, and effect of a nematode (Philometra saltatrix) in the ovaries of bluefish (Pomatomus saltatrix)
Examination of 203 adult bluefish (Pomatomus saltatrix) from
Long Island, New York, in 2002 and 2003 and 66 from the Outer Banks, North Carolina, in 2003 revealed the presence of dracunculoid nematodes (Philometra saltatrix) in the ovaries of female fish. Percent prevalence reached 88% in July and then decreased after the peak of the spawning season. Bluefish contained up to 100 parasites per fish. Infection was associated with a range of disorders, including hemorrhage, inf lammation, edema, prenecrotic
and necrotic changes, and follicular atresia, that may prevent proper development of oocytes and probably affect bluefish fecundity. Historical occurrences, life cycle, and geographical distribution of this nematode remain largely unknown, but may play important roles in recruitment
processes of bluefish
Simulation study of pressure and temperature dependence of the negative thermal expansion in Zn(CN)(2)
12 pages, 16 figures12 pages, 16 figures12 pages, 16 figures12 pages, 16 figure
Rigid unit modes in tetrahedral crystals
The 'rigid unit mode' (RUM) model requires unit blocks, in our case
tetrahedra of SiO_4 groups, to be rigid within first order of the displacements
of the O-ions. The wave-vectors of the lattice vibrations, which obey this
rigidity, are determined analytically. Lattices with inversion symmetry yield
generically surfaces of RUMs in reciprocal space, whereas lattices without this
symmetry yield generically lines of RUMs. Only in exceptional cases as in
beta-quartz a surface of RUMs appears, if inversion symmetry is lacking. The
occurence of planes and bending surfaces, straight and bent lines is discussed.
Explicit calculations are performed for five modifications of SiO_2 crystals.Comment: 18 pages, 6 figures, improved notatio
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CamGrid: Experiences in constructing a university-wide, Condor-based grid at the University of Cambridge
Proceedings of the 2004 UK e-Science All Hands Meeting, 31st August - 3rd September, Nottingham UKIn this article we describe recent work done in building a university-wide grid at the University of Cambridge based on the Condor middleware [1]. Once the issues of stakeholder concerns (e.g.
security policies) and technical problems (e.g. firewalls and private IP addresses) have been taken into account, a solution based on two separate Condor environments was decided on. The first of these is a single large pool administered centrally by the University Computing Service (UCS) and
the second a federated service of flocked Condor pools belonging to various departments and run over a Virtual Private Network (VPN). We report on the current status of this ongoing work
RXTE Observations of LMC X-1 and LMC X-3
Of all known persistent stellar-mass black hole candidates, only LMC X-1 and
LMC X-3 consistently show spectra that are dominated by a soft, thermal
component. We present results from long (170ksec) Rossi X-ray Timing Explorer
(RXTE) observations of LMC X-1 and LMC X-3 made in 1996 December. The spectra
can be described by a multicolor disk blackbody plus an additional high-energy
power-law. Even though the spectra are very soft (Gamma is about 2.5), RXTE
detected a significant signal from LMC X-3 up to energies of 50keV, the hardest
energy at which the object was ever detected.
Focusing on LMC X-3, we present results from the first year of an ongoing
monitoring campaign with RXTE which started in 1997 January. We show that the
appearance of the object changes considerably over its ~200d long cycle. This
variability can either be explained by periodic changes in the mass transfer
rate or by a precessing accretion disk analogous to Her X-1.Comment: 4 pages, 5 figures, also available at
http://aitzu3.ait.physik.uni-tuebingen.de/publications/preprints1998.html to
be published in "Highlights of X-Ray Astronomy, a symposium in honour of
Joachim Truemper" (B. Aschenbach et al., eds.), MPE Repor
Pair distribution functions calculated from interatomic potential models using the General Utility Lattice Program.
A new module has been developed for the widely used General Utility Lattice\ud
Program (GULP). The phonon-based theory developed by Chung & Thorpe\ud
[Phys. Rev. B (1999), 59, 4807–4812] to calculate pair distribution function\ud
(PDF) peak widths has been utilized to give a selection of commonly used\ud
correlation functions. A numerical library of neutron scattering information is\ud
now available within GULP, and is used to produce results that can be\ud
compared with neutron scattering experimental data. The influence of different\ud
phonon modes on the PDF can be assessed by excluding modes above or below\ud
a cut-off frequency. Results are presented for sample crystallographic systems,\ud
MgO, SrTiO3 and -cristobalite, as well as CaxSr1xTiO3 at x = 0.5, which makes\ud
use of the capability to handle partial occupancies to compare different Ca/Sr\ud
ordering arrangements with a disordered model in which every Ca/Sr site has\ud
50% occupancy of both species
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