296 research outputs found
Partial characterization of a Pasteuria sp. attacking the citrus nematode, Tylenchulus semipenetrans, in Florida
Des juvéniles et des mâles du nématode des citrus, #Tylenchulus semipenetrans, infestés par #Pasteuria sp. ont été détectés dans des échantillons de sol de vergers de citrus de la partie centrale de la Floride. Au cours d'essais au laboratoire, il a été observé que trois à seize endospores s'attachent à la cuticule du nématode. Des endospores mûres sont présentes à l'intérieur du nématode 18 jours après l'attache des endospores. Le développement du parasite est asynchrone, dépendant du spécimen du nématode. Chez les mâles, la région du corps contenant les spermatocytes n'est pas colonisée. Les juvéniles de deuxième stade et les mâles infestés contiennent de 320 à 400 endospores (18 jours après l'attache des endospores, à 25 °C). Les femelles ne sont pas parasitées et aucune endospore n'a été détectée sur leur cuticule. Les endospores de #Pasteuria sp. ne s'attachent pas à la cuticule de #Meloidogyne incognita, M. javanica, Radopholus citrophilus ou #R. similis$. (Résumé d'auteur
Classical stability of U(1)_A domain walls in dense matter QCD
It was recently shown that there exists metastable U(1)_A domain wall
configurations in high-density QCD (\mu >> 1 GeV). In the following we will
assess the stability of such non-trivial field configurations at intermediate
densities (\mu < 1 GeV). The existence of such configurations at intermediate
densities could have interesting consequences for the physics of neutron stars
with high core density.Comment: 13 pages, 2 Postscript figures, typos correcte
Global Strings in High Density QCD
We show that several types of global strings occur in colour superconducting
quark matter due to the spontaneous violation of relevant U(1) symmetries.
These include the baryon U(1)_B, and approximate axial U(1)_A symmetries as
well as an approximate U(1)_S arising from kaon condensation. We discuss some
general properties of these strings and their interactions. In particular, we
demonstrate that the U(1)_A strings behave as superconducting strings. We draw
some parallels between these strings and global cosmological strings and
discuss some possible implications of these strings to the physics in neutron
star cores.Comment: LaTeX JHEP-format (26 pages) Option in source for REVTeX4 forma
Drum vortons in high density QCD
Recently it was shown that high density QCD supports of number of topological
defects. In particular, there are U(1)_Y strings that arise due to K^0
condensation that occurs when the strange quark mass is relatively large. The
unique feature of these strings is that they possess a nonzero K^+ condensate
that is trapped on the core. In the following we will show that these strings
(with nontrivial core structure) can form closed loops with conserved charge
and currents trapped on the string worldsheet. The presence of conserved
charges allows these topological defects, called vortons, to carry angular
momentum, which makes them classically stable objects. We also give arguments
demonstrating that vortons carry angular momentum very efficiently (in terms of
energy per unit angular momentum) such that they might be the important degrees
of freedom in the cores of neutron stars.Comment: 11 pages, accepted for publication in Physical Review
Charge Neutrality of the Color-Flavor Locked Phase from the Low Energy Effective Theory
We investigate the issue of charge neutrality of the CFL phase of dense
quark matter using the low energy effective theory of high density QCD. We show
that the local electric and color charge neutrality of the ground state in a
homogeneous color superconducting medium follows from its dynamics. We also
consider the situation of a spatially inhomogeneous medium, such as may be
found in a neutron star core. We find that spatial inhomogeneity results in the
generation of electric fields, and positrons/electrons may be present in the
ground state. We estimate the concentration of charged leptons in the ground
state to be and consider their influence on the
opacity of the medium with respect to the modified photons.Comment: typos corrected, this version to appear in PR
- …