The Apparent Fractal Conjecture

This short communication advances the hypothesis that the observed fractal structure of large-scale distribution of galaxies is due to a geometrical effect, which arises when observational quantities relevant for the characterization of a cosmological fractal structure are calculated along the past light cone. If this hypothesis proves, even partially, correct, most, if not all, objections raised against fractals in cosmology may be solved. For instance, under this view the standard cosmology has zero average density, as predicted by an infinite fractal structure, with, at the same time, the cosmological principle remaining valid. The theoretical results which suggest this conjecture are reviewed, as well as possible ways of checking its validity.Comment: 6 pages, LaTeX. Text unchanged. Two references corrected. Contributed paper presented at the "South Africa Relativistic Cosmology Conference in Honour of George F. R. Ellis 60th Birthday"; University of Cape Town, February 1-5, 199

Spatial and observational homogeneities of the galaxy distribution in standard cosmologies

This work discusses the possible empirical verification of the geometrical concept of homogeneity of the standard relativistic cosmology considering its various definitions of distance. We study the physical consequences of the distinction between the usual concept of spatial homogeneity (SH), as defined by the Cosmological Principle, and the concept of observational homogeneity (OH), arguing that OH is in principle falsifiable by means of astronomical observations, whereas verifying SH is only possible indirectly. Simulated counts of cosmological sources are produced by means of a generalized number-distance expression that can be specialized to produce either the counts of the Einstein-de Sitter (EdS) cosmology, which has SH by construction, or other types of counts, which do, or do not, have OH by construction. Expressions for observational volumes and differential densities are derived with the various cosmological distance definitions in the EdS model. Simulated counts that have OH by construction do not always exhibit SH features. The reverse situation is also true. Besides, simulated counts with no OH features at low redshift start showing OH characteristics at high redshift. The comoving distance seems to be the only distance definition where both SH and OH appear simultaneously. The results show that observations indicating possible lack of OH do not necessarily falsify the standard Friedmannian cosmology, meaning that this cosmology will not necessarily always produce observable homogeneous densities. The general conclusion is that the use of different cosmological distances in the characterization of the galaxy distribution lead to significant ambiguities in reaching conclusions about the behavior of the large-scale galaxy distribution in the Universe.Comment: 12 pages, 12 figures, LaTeX. Matches the final version sent to the journal. Accepted for publication in "Astronomy and Astrophysics

No sex-biased dispersal in a primate with an uncommon social system-cooperative polyandry.

An influential hypothesis proposed by Greenwood (1980) suggests that different mating systems result in female and male-biased dispersal, respectively, in birds and mammals. However, other aspects of social structure and behavior can also shape sex-biased dispersal. Although sex-specific patterns of kin cooperation are expected to affect the benefits of philopatry and dispersal patterns, empirical evidence is scarce. Unlike many mammals, Saguinus geoffroyi (Geoffroy's tamarin) has a breeding system in which typically multiple males mate with a single breeding female. Males typically form cooperative reproductive partnerships between relatives, whereas females generally compete for reproductive opportunities. This system of cooperative polyandry is predicted to result in female-biased dispersal, providing an opportunity to test the current hypotheses of sex-biased dispersal. Here we test for evidence of sex-biased dispersal in S. geoffroyi using demographic and genetic data from three populations. We find no sex bias in natal dispersal, contrary to the prediction based on the mating patterns. This pattern was consistent after controlling for the effects of historical population structure. Limited breeding opportunities within social groups likely drive both males and females to disperse, suggesting that dispersal is intimately related to the social context. The integration of genetic and field data revealed that tamarins are another exception to the presumed pattern of male-biased dispersal in mammals. A shift in focus from mating systems to social behavior, which plays a role in most all processes expected to influence sex-bias in dispersal, will be a fruitful target for research both within species and across taxa

Estado Confusional Agudo após Corticoterapia Inalada

Background: The connection between corticotherapy and neuropsychiatric symptoms is widely known, being one of the first questions we need to assess when presenting with first episode psychiatric symptoms or confusional state. Aims: To date, data on cases related to inhaled corticotherapy and neuropsychiatric effects is scarce. In this paper we describe a rare case in a young woman. Methods: The clinical case presented led us to try to understand the data published on the subject in order to discuss it in greater length. Results and Conclusions: We present and discuss a 27-year-old patient’s case, with no previous psychiatric disease, who was admitted to our Psychiatric ward after the onset of severe acute behavioural disturbance characterized by aggressiveness, visual and auditory hallucinatory activity, misidentification and altered conscience status. It was later found that seven days earlier she had been prescribed inhaled corticotherapy for a minor respiratory infection. A few days after corticotherapy withdrawal, the clinical symptoms improved significantly.info:eu-repo/semantics/publishedVersio

Western iberian granites: a contribution to their geodynamic interpretation

[Resumo] Este trabalho apresenta fundamentalmente urna síntese do conhecimento dos granitos peninsulares, obtido através das várias abordagéns c1ássicas (geocronológica, peuográfica, estrutural e geoquímica). Existem já muitos dados disponíveis que «catalogados» e reinterpretados no quadro do conhecimento fornecido por outras disciplinas da Geologia, possibilitam a sua interpreta~ao geodinamica. Dá-se enfase ás c1assifica~6es baseadas em datos mineralógicos e estruturais, possiveis de obter no campo que, conjuntamente com dados geocronológicos, permitem reconhecer, como primeiros grandes grupos: granitos pré orogénicos, orogénicos e tardi/pós orogénicos. Os granitos pré orogénicos sao contemporaneos do vulcanismo estratificado, com que se procuram relacionar. Ocorrem em alinhamentos, referenciados no texto, e que se procuram interpretar como resultantes de falhas profundas, recorrentes, que terao permitido a ascensao, de magmas gerados em níveis profundos da crusta (e manto?). Contudo, a maioria dos granitos peninsulares anté-mesozoicos, sao contemporaneos da deforma~aohercínica (orogénicos). Estes granitos, onde tem sido reconhecida a existencia de vários subgrupos, ocorrendo geralmente associados a entidades estruturais importantes, apresentam características diferentes conforme as zonas paleogeográficas e estruturais peninsulares em que ocorrem e o periodo da sua instala~ao. As suas associaçoes com rochas de naturaleza mais máfica sao menos frequentes nas ZCI e ZAWL, indicando maior envolvimento da crusta continental nestas zonas (maior espessamento da crusta, durante a colisao hercínica?). Os granitos tardi/pós orogénicos ocorrem em todas as regi6es muitas vezes associados a grandes desligamentos de rejogo tardio. Tecem-se ainda algumas considera~6es relativas ao significado da escassez de rochas graníticas no domínio meridional da ZCI que se considera como urna regiao de divergencia da estrutura~aopré-hercínica, e apresenta-se um modelo geodinamico do enquadramento dos tipos principais de granitos orogénicos. Faz-se ainda urna síntese dos resultados obtidos em domíniosmenos clássicos, tais como a geoquímica estatística e a geofísica, no sentido de suscitar novas abordagens do tema.[Abstract] These paper presents an integrated review ()f the current geochronological, petrological, structural and geochemical knowledge on the western iberian granites. The available database is now large enough to allow a geodynamic interpretation of their genesis and installation. The field classifications based on petrographic and structural criteria together with geochronological data lead to the recognization of three first order groups: pre-orogenic, orogenic an tardi- post-orogenic granites. The pre-orogenic granites are contemporaneous with the stratified paleozoic volcanic rocks with which they are geneticaly correlated. They occur along lineaments which are interpreted as resulting from deep recurrent faults along which the magmas carne up. Many rocks from these lineaments present low Sri ratios suggesting generation at deep (rustal (or mantelic?) regions. However, the great majority of Iberia ante-mesozoic granites, are contemporaneous with the hercynian deformation (orogenic granites). Several subgroups of these granites have been recognised, all of them usually associated with important tectonic structures. They present characteristcs which are specific of the paleogeographic and structural zones where they accur and of its time of intrusion. Tardi- post-orogenic granites, usually assoeiated with younger deep fracturation, occur aH over Iberia. The granite /maphic rock associations are more frequent in the Ossa Morena and the Cantabric zones than in the Centro-Iberian and the Asturic-West-Leonesa zones, suggesting more crustal intervention on the generation of the granites in these two last zones (more crustal thickness at the time of the hercynian F32 collisiona!. phase). The scarcity of granitic rocks in the southern part of the Centro-Iberian zone is discussed. The general absence of granites and other data suggest that this region could have been a «continental plateau» from which the pre-hercynan structuration was divergent. A geodinamic model is proposed based in these ideas. A review of data obtained by less conventional means -such as geophysics and statistical geochemistry- is presented in the hope of suggestin new approaches to the study of the iberian granite

Desempenho produtivo de oito clones de cajueiro-anão precoce cultivados sob regime de sequeiro no cerrado sul maranhense.

bitstream/CPAMN-2009-09/17841/1/CT153.pd

Group theory for structural analysis and lattice vibrations in phosphorene systems

Group theory analysis for two-dimensional elemental systems related to phosphorene is presented, including (i) graphene, silicene, germanene and stanene, (ii) dependence on the number of layers and (iii) two stacking arrangements. Departing from the most symmetric $D_{6h}^{1}$ graphene space group, the structures are found to have a group-subgroup relation, and analysis of the irreducible representations of their lattice vibrations makes it possible to distinguish between the different allotropes. The analysis can be used to study the effect of strain, to understand structural phase transitions, to characterize the number of layers, crystallographic orientation and nonlinear phenomena.Comment: 24 pages, 3 figure