26,593 research outputs found
Genera of the bee tribe Reedapini (Hymenoptera: Colletidae)
Those bees classified in the genera Reedapis Michener and Cephalocolletes Michener are discussed and organized into a new tribe, Reedapini Engel. In addition, three species formerly classified in Cephalocolletes are removed to two new genera: Lonchopriscus Engel, new genus, with the species Lonchopriscus crassipunctatus (Urban), new combination, and Cactocolletes Engel, new genus, for Cactocolletes isabelae (Urban), new combination, and C. rugatus (Urban), new combination. The tribe and its constituent genera are diagnosed, and a key is provided for the identification of the latter along with their included species
A new species of Mermiglossa from Kenya, with comments on the arrangement of Old World Panurginae (Hymenoptera: Andrenidae)
A new species of the panurgine bee genus Mermiglossa Friese (Panurginae) is described and figured from females captured near Voi in the southern part of the former Coast Province, Kenya, a historical type locality for several bee species. Mermiglossa voicola Ascher & Engel, new species, is distinguished from the only other species of the genus, M. rufa Friese from central Namibia. The new species is readily identified due to its black rather than red metasoma and compound eyes slightly convergent above rather than parallel-sided. The new species raises the total number of described bee species for Kenya to 343, extends the known distribution of its genus and subtribe from the Namib Desert of southwestern Africa to the western edge of the Nviri Desert of East Africa, and provides further evidence of extensive biogeographic connections between these disjunct xeric areas. Recent changes in the family-group classification of Old World Panurginae are discussed in relation to recognition of Mermiglossina as a valid subtribe within an expanded tribe Panurgini also including the New World perditines
A new species of Ptiloglossa from Mexico, with new records of Ptiloglossa cyaniventris from Panama and Costa Rica (Hymenoptera: Colletidae)
A new bee species of the genus Ptiloglossa Smith (Colletidae: Diphaglossinae: Caupolicanini) is described and figured from Jalisco, Mexico, while new records are provided for Ptiloglossa cyaniventris Friese from Panama and a single locality in Costa Rica.  Ptiloglossa chamelensis Ayala & Engel, new species, is endemic to Mexico and is close to P. rugata Moure, both sharing a similar shape in the fused metatibial spur, but in the new species the metatibia is widest at the level of the spur, and the female has black integument with dense yellow pubescence on metasomal terga I–IV.  Ptiloglossa cyaniventris is newly recorded from males collected in Panama and Costa Rica and is characteristic for its dark integument, with intense metallic blue highlights on the metasomal terga, the narrow and long metatibia, and elongate metabasitarsus with an anterior, longitudinal ridge and slightly depressed outer surface
Impact of Uncertainties in Hadron Production on Air-Shower Predictions
At high energy, cosmic rays can only be studied by measuring the extensive
air showers they produce in the atmosphere of the Earth. Although the main
features of air showers can be understood within a simple model of successive
interactions, detailed simulations and a realistic description of particle
production are needed to calculate observables relevant to air shower
experiments. Currently hadronic interaction models are the main source of
uncertainty of such simulations. We will study the effect of using different
hadronic models available in CORSIKA and CONEX on extensive air shower
predictions.Comment: 12 pages, 6 figures, to appear in the proceedings of International
Conference on Interconnection between High Energy Physics and Astroparticle
Physics: From Colliders to Cosmic Rays, Prague, Czech Republic, 7-13 Sep 200
Intrinsic-Density Functionals
The Hohenberg-Kohn theorem and Kohn-Sham procedure are extended to
functionals of the localized intrinsic density of a self-bound system such as a
nucleus. After defining the intrinsic-density functional, we modify the usual
Kohn-Sham procedure slightly to evaluate the mean-field approximation to the
functional, and carefully describe the construction of the leading corrections
for a system of fermions in one dimension with a spin-degeneracy equal to the
number of particles N. Despite the fact that the corrections are complicated
and nonlocal, we are able to construct a local Skyrme-like intrinsic-density
functional that, while different from the exact functional, shares with it a
minimum value equal to the exact ground-state energy at the exact ground-state
intrinsic density, to next-to-leading order in 1/N. We briefly discuss
implications for real Skyrme functionals.Comment: 15 page
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