Primera cita de Leptodactylus ocellatus (Linnaeus, 1758) (Amphibia, Anura, Leptodactylidae) en Bolivia y comentarios sobre especies próximas

The distributions of Leptodactylus ocellatus, L. chaquensis, and L. macrosternum in Bolivia are reviewed and discussed. Leptodactylus chaquensis and L. ocellatus are easily distinguished morphologically but L. chaquensis and L. macrosternum are indistinguishable. In Bolivia, L. ocellatus is known only from a single locality in the Paraguay River basin, which is reported here for the first time. Leptodactylus chaquensis occurs in the Chaco region of southeastern Bolivia, but it is unknown to what extent this species enters the Cerrado. The distribution boundaries and putative overlapping areas of L. chaquensis and L. macrosternum are unknown.Se revisa y discute la distribución de Leptodactylus ocellatus, L. chaquensis y L. macrosternum en Bolivia. Mientras que, morfológicamente, L. chaquensis y L. ocellatus se diferencian fácilmente, L. chaquensis y L. macrosternum son imposibles de distinguir. Leptodactylus ocellatus se encuentra en la parte boliviana de la cuenca del río Paraguay, aunque de momento se conoce solamente de una localidad, que se cita aquí por primera vez. Leptodactylus chaquensis habita en el Chaco, pero se deconoce hasta dónde penetra en el Cerrado. No se conocen los límites de las áreas de distribución y posibles zonas de solapamiento de L. chaquensis y L. macrosternum

Mapping properties of weakly singular periodic volume potentials in Roumieu classes

The analysis of the dependence of integral operators on perturbations plays an important role in the study of inverse problems and of perturbed boundary value problems. In this paper, we focus on the mapping properties of the volume potentials with weakly singular periodic kernels. Our main result is to prove that the map which takes a density function and a periodic kernel to a (suitable restriction of the) volume potential is bilinear and continuous with values in a Roumieu class of analytic functions. This result extends to the periodic case of some previous results obtained by the authors for nonperiodic potentials, and it is motivated by the study of perturbation problems for the solutions of boundary value problems for elliptic differential equations in periodic domains

The taxonomic status of Hyla roeschmanni De Grys, 1938 (Anura: Hylidae)

Accepted by S. Carranza: 18 May 2006; published: 12 Jun. 2006The taxonomic status of Hyla roeschmanni De Grys, 1938 (Anura: Hylidae) is reviewed. We place Hyla roeschmanni as a junior synonym of Hypsiboas raniceps Cope, 1862. Because the holotype of Hyla roeschmanni was destroyed, we designate a neotype from Department Beni, Bolivia, and provide a description of the neotype.This work was partially funded by the projects REN/GLO 2001-1046 and CGL2005-03156 of the Spanish Ministry of Education and Science (I. De la Riva, Principal Investigator).Peer reviewe

Distribution and morphological variation of Eleutherodactylus mercedesae Lynch & McDiarmid, 1987 (Amphibia, Anura, Leptodactylidae) with first record for Peru

Accepted by S. Carranza: 19 May 2006; published: 3 Aug. 2006 49[EN] We report new distributional information for Eleutherodactylus mercedesae in Bolivia, and provide the first record for Peru based on an adult female. This species, previously endemic to Bolivia, now ranges across about 1000 km in cloud forests on the Amazonian slopes of the Andes from southern Peru to central Bolivia. We provide the first morphological description of females based on two specimens, compare them with the male type and paratype, add some observations to the original description, and comment on variation in the species.[ES] Aportamos información novedosa sobre la distribución de Eleutherodactylus mercedesae en Bolivia y la primera cita para Perú, basada en una hembra adulta. Esta especie se consideraba hasta ahora endémica para Bolivia. Su rango conocido de distribución comprende actualmente unos 1000 km de los bosques nublados de las laderas amazónicas de los Andes, desde el sur de Perú al centro de Bolivia. Se describe por primera vez la hembra de esta especie en base a dos ejemplares, que son comparados con el holotipo y el paratipo. Añadimos algunas observaciones sobre la descripción original y la variación morfológica de la especie.This work was partially funded by projects REN/GLO 2001-1046 and CGL2005-03156 of the Spanish Ministry of Education and Science (I. De la Riva, Principal Investigator).Peer reviewe

The Distress Calls of \u3cem\u3eLeptodactylus chaquensis\u3c/em\u3e Cei, 1950 and \u3cem\u3eLeptodactylus elenae\u3c/em\u3e Heyer, 1978 (Anura: Leptodactylidae)

We describe the distress calls of Leptodactylus chaquensis and Leptodactylus elenae. They each consist of a single, long, tonal sound with complex harmonic structure and complex frequency modulation. The distress calls of both species are different from their respective advertisement calls. Moreover, there are also clear interspecific differences. Harmonic frequencies in L. elenae are higher, there are fewer emphasized harmonics and the call is shorter and repeated at a higher rate (sometimes paired) than the call of L. chaquensis. Call duration, call rate, and position of the dominant harmonic change with the strength of the stimulus that the individuals are under; therefore, they are more variable than their respective advertisement calls

UAV-derived photogrammetric point clouds and multispectral indices for fuel estimation in Mediterranean forests

Sensors attached to unmanned aerial vehicles (UAVs) allow estimating a large number of forest attributes related to forest fuels. This study assesses photogrammetric point clouds and multispectral indices obtained from a fixed-wing UAV for the classification of Prometheus fuel types in 82 forest plots in Aragón (NE Spain). Images captured by an RGB camera and a multispectral sensor allowed generating high density photogrammetric point clouds (RGB: 3000 points/m2; multispectral: 85 points/m2), which were normalized using alternatively a Digital Elevation Model (DEM) of 0.5, 1, and 2 m resolution. A set of structural and textural variables were derived from the normalized point cloud heights, and for the latter, the gray-level co-occurrence matrix (GLCM) approach was used. Multispectral images were also used to create seven spectral vegetation indices. The most relevant structural, textural, and spectral variables to introduce into the fuel types classification models were selected using Dunn's test, which included: the vegetation height at the 50th percentile, the coefficient of variation of the heights, the percentage of returns above 4 m, the mean textural dissimilarity, and the mean of the Green Chlorophyll Index. Three different data samples were introduced in the models: i) the relevant structural and textural variables from the RGB camera (RGB data sample); ii) the relevant structural, textural, and spectral variables from the multispectral sensor (MS data sample); and iii) the relevant structural and textural variables from the RGB camera plus the relevant spectral variable from the multispectral sensor (integrated data sample). After comparing three machine learning classification techniques (Random Forest, and Linear and Radial Support Vector Machine), the best results were obtained with Random Forest with k-fold cross-validation (k-10) and the integrated data sample with normalized point clouds at 0.5 m DEM resolution (overall accuracy = 71%). The variables successfully identified the Prometheus main fire carriers (i.e., shrubs or trees) and confusions were mainly located within the fuel types of the same dominant stratum, especially in fuel types 3 and 6. These results demonstrate the ability of UAV imagery to classify forest fuels in Mediterranean environments when RGB and multispectral data are combined

Excitons and charged excitons in semiconductor quantum wells

A variational calculation of the ground-state energy of neutral excitons and of positively and negatively charged excitons (trions) confined in a single-quantum well is presented. We study the dependence of the correlation energy and of the binding energy on the well width and on the hole mass. The conditional probability distribution for positively and negatively charged excitons is obtained, providing information on the correlation and the charge distribution in the system. A comparison is made with available experimental data on trion binding energies in GaAs-, ZnSe-, and CdTe-based quantum well structures, which indicates that trions become localized with decreasing quantum well width.Comment: 9 pages, 11 figure

Interlaminar Response of LSI-Produced C/SiC Ceramic Matrix Composites: Experiments and Modelling

This work investigates the interlaminar properties of a C/SiC composite produced by Liquid Silicon Infiltration, combining experiments based on Double Cantilever Beam tests and numerical analyses. Experimentally, a method to obtain pre-cracks with sharp tips at precise locations is proposed, and specimens with different thickness are used to investigate the effects of bending stress states in the delamination process. The properties of tri-linear Cohesive Zone Models for the modelling of delamination are identified numerically, by using automatic regression techniques without requiring additional assumptions or testing. Fiber bridging effects were observed and modelled, including the evaluation of the process zone lengths with different experimental, analytical, and numerical methods. Overall, the work provides a qualitative insight in the delamination process of long fiber reinforced C/SiC laminates produced with a cost-affordable technique and proposes an experimental and numerical protocol to characterize and model delamination phenomena, taking into account the scattering of material properties