13,064 research outputs found
A revision of the striatella species group of the genus Rhagoletis (Diptera: Tephritidae)
A taxonomic revision of species of the striatella group, including descriptions ofthree new species from Mexico, Nicaragua and Costa Rica is presented. To date we recognize 6 species in this group: Rhagoletis striatella, R. jamaicensis, R. macquartii, R. triangularis n. sp., R. nicaraguensis n. sp., and R. solanophaga n. sp. Information and records about their distribution, known host plants, and morphological relationships among the species are discussed. A key to the species within the group is presented.Se presenta una revision taxonomic a de las especies del grupo striatella, la cual incluye descripciones de tres nuevas especies provenientes de Mexico, Nicaragua y Costa Rica. Ala fecha reconocemos 6 especies en este grupo: Rhagoletis striatella, R. jamaicensis, R. macquartii, R. triangularis n. sp., R. nicaraguensis n. sp., and R. solanophaga n. sp .. Se discute informacion sobre su distribucion, plantas hospederas conocidas, y las relaciones morfologicas entre sus especies. Ademas se presenta una clave para separar todas las especies del grupo
Magnetically Induced Metallic Phase in Superconducting Tantalum Films
We have studied the electronic transport properties of homogeneously
disordered superconducting tantalum thin films in magnetic fields. The films
exhibit three distinct transport regimes in the zero temperature limit which we
identify as superconducting, metallic, and insulating phases. The metallic
phase is unexpected. The transport characteristics of this metallic phase are
found to be similar to those of MoGe films and high mobility dilute
two-dimensional electrons or holes confined in semiconductor interface or
transistor geometry.Comment: four pages, four figure
Automorphisms of moduli spaces of symplectic bundle
Let X be an irreducible smooth complex projective curve of genus at least 3.
Fix a line bundle L on X. Let M_{Sp}(L) be the moduli space of symplectic
bundles (E, ExE ---> L) on X, with the symplectic form taking values in L. We
show that the automorphism group of M_{Sp}(L) is generated by automorphisms
sending E to ExM, where M is a 2-torsion line bundle, and automorphisms induced
by automorphisms of X.Comment: 21 page
Charged current neutrino induced coherent pion production
We analyze the neutrino induced charged current coherent pion production at
the energies of interest for recent experiments like K2K and MiniBooNE. Medium
effects in the production mechanism and the distortion of the pion wave
function, obtained solving the Klein Gordon equation with a microscopic optical
potential, are included in the calculation. We find a strong reduction of the
cross section due to these effects and also substantial modifications of the
energy distributions of the final lepton and pion.Comment: 11 pages, 6 figures. Some details and new references added; results
unchanged. Accepted in PR
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