521 research outputs found
Description of Bathysciola liqueana n. sp. from the central Pyrenees. Designation of lectotypes and distribution data for species of the B. meridionalis group (Jacquelin du Val, 1854) (Insecta, Coleoptera, Leiodidae, Cholevinae, Leptodirini)
Se describe una nueva especie del género Bathysciola Jeannel, 1910 (B. liqueana sp. n.) que pertenece al grupo "meridionalis". Se ha encontrado en medio subterráneo, en la Grotte de Liqué, macizo de Larroque, Moulis, Ariège, Francia. La especie más similar es Bathysciola meridionalis (Jacquelin du Val, 1854), también descubierta en Ariège. Los caracteres distintivos se encuentran básicamente en el edeago: es corto, ancho, con el ápice redondeado en B. liqueana sp. n. y largo, estrecho, con el ápice puntiagudo en B. meridionalis. Se discute su posición taxonómica y se completa el estudio con ilustraciones de las estructuras que permiten distinguir estos táxones, así como también los datos de distribución de que se dispone, incluyendo también a B. finismillennii Fresneda & Salgado, 2006. Se designan los lectotipos de B. meridionalis y de B. nitidula Normand, 1907.
Palabras clave: Coleoptera, Leiodidae, Bathysciola, Grupo "meridionalis", Pirineos.Se describe una nueva especie del género Bathysciola Jeannel, 1910 (B. liqueana sp. n.) que pertenece al grupo "meridionalis". Se ha encontrado en medio subterráneo, en la Grotte de Liqué, macizo de Larroque, Moulis, Ariège, Francia. La especie más similar es Bathysciola meridionalis (Jacquelin du Val, 1854), también descubierta en Ariège. Los caracteres distintivos se encuentran básicamente en el edeago: es corto, ancho, con el ápice redondeado en B. liqueana sp. n. y largo, estrecho, con el ápice puntiagudo en B. meridionalis. Se discute su posición taxonómica y se completa el estudio con ilustraciones de las estructuras que permiten distinguir estos táxones, así como también los datos de distribución de que se dispone, incluyendo también a B. finismillennii Fresneda & Salgado, 2006. Se designan los lectotipos de B. meridionalis y de B. nitidula Normand, 1907.
Palabras clave: Coleoptera, Leiodidae, Bathysciola, Grupo "meridionalis", Pirineos.We describe a new species of the genus Bathysciola Jeannel, 1910 (B. liqueana n. sp.) belonging to the "meridionalis" group. It was collected in a subterranean environment, in Liqué cave, Larroque massif, Moulis, Ariège, France. The closest species is Bathysciola meridionalis (Jacquelin du Val, 1854), also known from Ariège. The new species differs mainly in morphological characteristics of the aedeagus: short, wide, with rounded apex in B. liqueana n. sp. whereas it is long, narrow, with pointed apex in B. meridionalis. We discuss the taxonomical position of the new species and provide illustrations of structures showing the differences between the two species, along with distribution data, including for B. finismillennii Fresneda & Salgado, 2006. We designate lectotypes of B. meridionalis and B. nitidula Normand, 1907.
Key words: Coleoptera, Leiodidae, Bathysciola, "meridionalis" group, Pyrenees
Una nueva especie troglobiomorfa de Trechus Clairville, 1806 y evidencias de colonizaciones múltiples del medio subterráneo de los montes cantábricos (Coleoptera, Carabidae, Trechinae)
Se describe Trechus (Trechus) valenzuelai sp. n. de los montes cantábricos en España: Sierra de Cuera, en Asturias. La especie se ha encontrado en el medio subterráneo, en cuevas y dolinas. El estudio morfológico revela que se debe situar como especie hermana de Trechus escalerae Abeille de Perrin, 1903, en el clado de T. saxicola Putzeys, 1870. Se ha encontrado una sinapomorfía en los edeagos de T. escalerae y T. valenzuelai sp. n. que se describe e ilustra: el endofalo tiene una fanera con forma de porra, alargada, robusta y muy esclerotizada, en cuya base se encuentra un saco membranoso recubierto por espínulas. Se discute la taxonomía y la sistemática, y se aportan ilustraciones de las estructuras que muestran las diferencias entre T. escalerae y T. valenzuelai sp. n.; también se proporcionan datos relativos a la distribución y la biogeografía, así como hipótesis sobre los procesos de especiación, tomando como base de argumentación los datos moleculares previamente publicados, la estructura geológica de la región y los acontecimientos paleoclimáticos; se postulan procesos de colonización activa, simultáneos e independientes, del medio subterráneo. Se designa el lectotipo de T. escalerae.A new troglobiomorphic Trechus Clairville, 1806 and evidence of multiple colonizations in the subterranean environment of the Cantabrian mountains (Coleoptera, Carabidae, Trechinae)
We describe Trechus (Trechus) valenzuelai n. sp. from the Cantabrian area of Spain: Sierra de Cuera, Asturias. The species was collected in the subterranean environment, in caves and dolines. Morphological examination revealed that the new species is sister to Trechus escalerae Abeille de Perrin, 1903 within the T. saxicola clade. A synapomorphy of the male genitalia, shared by T. valenzuelai n. sp. and T. escalerae, is described and illustrated: the endophallus has a sclerotised piece shaped like a club, elongated, robust, strongly sclerotised and with a membranous sac covered with small spicules at the base. We discuss the taxonomy of the new species and provide illustrations of structures showing the differences between T. escalerae and T. valenzuelai n. sp., along with biogeographical and distributional data and hypotheses regarding the speciation events based on previously pubished molecular data, and the geological structure and the palaeoclimatology of their geographical area. We hypothesize that in this clade, the colonization of the subterranean environment was the result of multiple, independent and simultaneous colonization processes. A lectotype is designated for T. escalerae.Se describe Trechus (Trechus) valenzuelai sp. n. de los montes cantábricos en España: Sierra de Cuera, en Asturias. La especie se ha encontrado en el medio subterráneo, en cuevas y dolinas. El estudio morfológico revela que se debe situar como especie hermana de Trechus escalerae Abeille de Perrin, 1903, en el clado de T. saxicola Putzeys, 1870. Se ha encontrado una sinapomorfía en los edeagos de T. escalerae y T. valenzuelai sp. n. que se describe e ilustra: el endofalo tiene una fanera con forma de porra, alargada, robusta y muy esclerotizada, en cuya base se encuentra un saco membranoso recubierto por espínulas. Se discute la taxonomía y la sistemática, y se aportan ilustraciones de las estructuras que muestran las diferencias entre T. escalerae y T. valenzuelai sp. n.; también se proporcionan datos relativos a la distribución y la biogeografía, así como hipótesis sobre los procesos de especiación, tomando como base de argumentación los datos moleculares previamente publicados, la estructura geológica de la región y los acontecimientos paleoclimáticos; se postulan procesos de colonización activa, simultáneos e independientes, del medio subterráneo. Se designa el lectotipo de T. escalerae
Geophysical investigation and dynamic modelling of unstable slopes: case-study of Kainama (Kyrgyzstan)
The presence of massive Quaternary loess units at the eastern border of the Fergana Basin (Kyrgyzstan, Central Asia) makes this area particularly prone to the development of catastrophic loess earthflows, causing damages and injuries almost every year. Efficient disaster management requires a good understanding of the main causes of these mass movements, that is, increased groundwater pressure and seismic shaking. This paper focuses on the Kainama earthflow, mainly composed of loess, which occurred in 2004 April. Its high velocity and the long run-out zone caused the destruction of 12 houses and the death of 33 people. In summer 2005, a field survey consisting of geophysical and seismological measurements was carried out along the adjacent slope. By combination and geostatistical analysis of these data, a reliable 3-D model of the geometry and properties of the subsurface layers, as shown in the first part of the paper, was created. The analysis of the seismological data allowed us to point out a correlation between the thickness of the loess cover and the measured resonance frequencies and associated amplification potential. The second part of this paper is focused on the study of the seismic response of the slope by numerical simulations, using a 2-D finite difference code named FLAC. Modelling of the seismic amplification potential along the slope confirmed the results obtained from the seismological survey—strong amplifications at the crest and bottom of the slope where there is a thick loess cover and almost no amplification in the middle part of the slope. Furthermore, dynamic slope stability analyses were conducted to assess the influence of local amplifications and increased groundwater pressures on the slope failure. The results of the dynamic modelling, although preliminary, show that a combination of seismic and hydrologic origin (pore pressure build-up during the seismic shaking) is the most probable scenario responsible for the 2004 failur
Measurements of Sheath Currents and Equilibrium Potential on the Explorer VIII Satellite (1960 xi)
Experimental data were obtained from the Explorer VIII satellite on five parameters pertinent to the problem of the interaction of space vehicles with an ionized atmosphere. The five parameters are: photoemission current due to electrons emitted from the satellite surfaces as a result of solar radiation; electron and positive ion currents due to the diffusion of charged particles from the medium to the spacecraft; the vehicle potential relative to the medium, and the ambient electron temperature. Included in the experimental data is the aspect dependence of the photoemission and diffusion currents. On the basis of the observations, certain characteristics of the satellite's plasma sheath are postulated
Finite-size anyons and perturbation theory
We address the problem of finite-size anyons, i.e., composites of charges and
finite radius magnetic flux tubes. Making perturbative calculations in this
problem meets certain difficulties reminiscent of those in the problem of
pointlike anyons. We show how to circumvent these difficulties for anyons of
arbitrary spin. The case of spin 1/2 is special because it allows for a direct
application of perturbation theory, while for any other spin, a redefinition of
the wave function is necessary. We apply the perturbative algorithm to the
N-body problem, derive the first-order equation of state and discuss some
examples.Comment: 18 pages (RevTex) + 4 PS figures (all included); a new section on
equation of state adde
Path integrals on a flux cone
This paper considers the Schroedinger propagator on a cone with the conical
singularity carrying magnetic flux (``flux cone''). Starting from the operator
formalism and then combining techniques of path integration in polar
coordinates and in spaces with constraints, the propagator and its path
integral representation are derived. "Quantum correction" in the Lagrangian
appears naturally and no a priori assumption is made about connectivity of the
configuration space.Comment: LaTeX file, 9 page
A chiral bag model approach to delta electroproduction
Helicity amplitudes for the transition are calculated
using the cloudy bag model. A correction for center-of-mass motion is carried
out using a modified Peierls-Thouless projection method. This reduces the
magnitude of the transition amplitudes at small momentum transfer and enhances
them at modest momentum transfers. Our calculation shows that the pion cloud
contributes substantially to the transition helicity amplitudes, with the final
result giving reasonable agreement with the corresponding experimental values.Comment: 16 pages, 6 ps figures, revte
Remarks on the Configuration Space Approach to Spin-Statistics
The angular momentum operators for a system of two spin-zero
indistinguishable particles are constructed, using Isham's Canonical Group
Quantization method. This mathematically rigorous method provides a hint at the
correct definition of (total) angular momentum operators, for arbitrary spin,
in a system of indistinguishable particles. The connection with other
configuration space approaches to spin-statistics is discussed, as well as the
relevance of the obtained results in view of a possible alternative proof of
the spin-statistics theorem.Comment: 18 page
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