Effective Maxwell's equations in general periodic microstructures

We study the time harmonic Maxwell equations in a meta-material consisting of perfect conductors and void space. The meta-material is assumed to be periodic with period $\eta > 0$; we study the behaviour of solutions $(E^{\eta}, H^{\eta})$ in the limit $\eta \to 0$ and derive an effective system. In geometries with a non-trivial topology, the limit system implies that certain components of the effective fields vanish. We identify the corresponding effective system and can predict, from topological properties of the meta-material, whether or not it permits the propagation of waves

Study of four Neotropical species of tree crickets Oecanthus Serville, 1831 (Orthoptera, Gryllidae) using cytogenetic and molecular markers

Karyotypes in the worldwide subfamily Oecanthinae show variations in diploid number, chromosome morphology, and sex-chromosome system. This study described the chromosome set and phylogenetic relationships of four Neotropical species, Oecanthus lineolatus, O. valensis, O. pallidus, and O. pictus. We used classical cytogenetics and Bayesian Inference for phylogenetic reconstruction, using the mitochondrial genes COI, 12S rRNA, and 16S rRNA; and analyzed the phylogenetic patterns of changes in chromosome numbers, using ChromEvol. We observed differences in chromosome number among species and two different sex-chromosome systems. Oecanthus pictus showed 2n = 21, X0♂/22, XX♀; O. lineolatus, 2n = 20, XY♂/XX♀; and O. valensis and O. pallidus, 2n = 18, XY♂/XX♀. The karyotype of Oecanthus was asymmetric, one group with large chromosomes and variation in heterochromatin distribution, and another with small acrocentric chromosomes. The phylogenetic tree recovered two main groups: one with the Palearctic species and another with species from different bioregions, but with low posterior probability. The Neotropical species grouped separately, O. valensis and O. pictus with Nearctic and Ethiopian species, and O. pallidus and O. lineolatus in another, well-supported clade. Together, the phylogenic and chromosome data suggest descending dysploidy events during the evolution of the group

Cultura política de la democracia en Perú y en las Américas, 2014 : gobernabilidad democrática a través de 10 años del Barómetro de las Américas

El presente estudio es parte de un programa de investigaciones que el Proyecto de Opinión Pública de América Latina (LAPOP) viene llevando a cabo desde hace más de dos décadas. LAPOP es un consorcio de instituciones académicas y de investigación en las Américas, con sede central en Vanderbilt University, en Estados Unidos. En el proyecto LAPOP participan más de 30 instituciones de toda la región, cuyos esfuerzos tienen el propósito de producir estudios científicos, objetivos e independientes de opinión pública. Dichas investigaciones se enfocan principalmente en la medición de actitudes y comportamientos políticos relacionados con la democracia y la calidad de vida

Understanding the chromosomal evolution in cuckoos (Aves, Cuculiformes): a journey through unusual rearrangements

The Cuculiformes are a family of over 150 species that live in a range of habitats, such as forests, savannas, and deserts. Here, bacterial artificial chromosome (BAC) probes (75 from chicken and 14 from zebra finch macrochromosomes 1–10 +ZW and for microchromosomes 11–28 (except 16)) were used to investigate chromosome homologies between chicken and the squirrel cuckoo ( Piaya cayana). In addition, repetitive DNA probes were applied to characterize the chromosome organization and to explore the role of these sequences in the karyotype evolution of P. cayana. We also applied BAC probes for chicken chromosome 17 and Z to the guira cuckoo ( Guira guira) to test whether this species has an unusual Robertsonian translocation between a microchromosome and the Z chromosome, recently described in the smooth-billed ani ( Crotophaga ani). Our results revealed extensive chromosome reorganization with inter- and intrachromosomal rearrangements in P. cayana, including a conspicuous chromosome size and heterochromatin polymorphism on chromosome pair 20. Furthermore, we confirmed that the Z-autosome Robertsonian translocation found in C. ani is also found in G. guira, not P. cayana. These findings suggest that this translocation occurred prior to the divergence between C. ani and G. guira, but after the divergence with P. cayana

Comparison of calling songs in three allopatric populations of Endecous itatibensis (Orthoptera, Phalangopsinae)

Three isolated populations of the cricket Endecous itatibensis Rehn, 1918 had been analyzed to test the hypothesis of divergence in the calling song estridulation and to discuss its implications in the speciation process. The song registers were obtained from specimens in Corumbataí, Piraciacaba and Itatiba cities, state of São Paulo, Brazil. In the three analyzed populations, calling songs are composed by pairs of notes. Specimens from Corumbataí emit composed phrases with 3 to 18 pairs of notes, while those of Piracicaba and Itatiba have 1 to 3 pairs of notes. Inter- and intrapopulational variability in the frequencies of acoustic signals were detected. While recording the calling songs, other stridulations were registered, possibly from species of Orthoptera or Hemiptera. When the tapes were analyzed in the laboratory, it was verified that there was no overlap among the species' calling songs, in such a way that each species had their particular band of frequencies, avoiding interespecific acoustic competition

Morphological characterization of the proventriculus of Gryllus assimilis Fabricius (Orthoptera, Gryllidae)

The proventriculus morphology of the cricket Gryllus assimilis Fabricius, 1775 is described using scanning electron microscopy and the correlation of this structure with the feeding habits briefly considered

Adelosgryllus rubricephalus: a new genus and species of cricket (Orthoptera: Phalangopsidae)

Um novo gênero e espécie de grilo falangopsídeo Adelosgryllus rubricephalus é descrito. Ilustrações de espécimes macho e fêmea e a descrição dos escleritos fálicos, assim como os cromossomos e a distribuição geográfica conhecida são relatados. Uma discussão sobre a posição taxonômica desse grilo dentro da família Phalangopsidae é incluída.Adelosgryllus rubricephalus, a new genus and species of phalangopsid cricket are described. Illustrations of male and female specimens as well as descriptions of phallic sclerites, chromosomes and geographical known distribution are furnished. A discussion on the species taxonomic status of this cricket within the family is also included

FIGURE 2 in Anurogryllus Saussure, 1877 (Orthoptera: Gryllidae: Gryllinae) from southern Brazil: new species and new records

FIGURE 2. — Anurogryllus patos sp. nov. holotype general morphology. A—habitus, dorsal; B—habitus, ventral; C—head and pronotum, dorsal; D—head and pronotum, lateral; E—femur III, lateral; F—external tympanum in the tibia III; Ginternal tympanum in the tibia III; H—right tegmen, dorsal; I—supra-anal plate, dorsal; J—subgenital plate, ventral