Dispersive representation of the K pi vector form factor and fits to tau -> K pi nu(tau) and Ke3 data

Recently, we introduced several dispersive representations for the vector $K\pi$ form factor and fitted them to the Belle spectrum of $\tau \to K \pi \nu_\tau$. Here, we briefly present the model and discuss the results for the slope and curvature of $F_+(s)$ arising from the best fit. Furthermore, we compare the pole position of the charged $K^*(892)$ computed from our model with other results in the literature. Finally, we discuss the prospects of a simultaneous fit to $\tau \to K \pi \nu_\tau$ and $K_{e3}$ spectra.Comment: Talk given at "International Workshop on Effective Field Theories: from the pion to the upsilon", February 2009, Valencia, Spain. 7 pages, 2 figures. PoS style. Minor correction in figure

Comparison of musculoskeletal networks of the primate forelimb

Anatomical network analysis is a framework for quantitatively characterizing the topological organization of anatomical structures, thus providing a way to compare structural integration and modularity among species. Here we apply this approach to study the macroevolution of the forelimb in primates, a structure whose proportions and functions vary widely within this group. We analyzed musculoskeletal network models in 22 genera, including members of all major extant primate groups and three outgroup taxa, after an extensive literature survey and dissections. The modules of the proximal limb are largely similar among taxa, but those of the distal limb show substantial variation. Some network parameters are similar within phylogenetic groups (e.g., non-primates, strepsirrhines, New World monkeys, and hominoids). Reorganization of the modules in the hominoid hand compared to other primates may relate to functional changes such as coordination of individual digit movements, increased pronation/supination, and knuckle-walking. Surprisingly, humans are one of the few taxa we studied in which the thumb musculoskeletal structures do not form an independent anatomical module. This difference may be caused by the loss in humans of some intrinsic muscles associated with the digits or the acquisition of additional muscles that integrate the thumb more closely with surrounding structures

First anatomical network analysis of fore- and hindlimb musculoskeletal modularity in bonobos, common chimpanzees, and humans

Studies of morphological integration and modularity, and of anatomical complexity in human evolution typically focus on skeletal tissues. Here we provide the first network analysis of the musculoskeletal anatomy of both the fore- and hindlimbs of the two species of chimpanzee and humans. Contra long-accepted ideas, network analysis reveals that the hindlimb displays a pattern opposite to that of the forelimb: Pan big toe is typically seen as more independently mobile, but humans are actually the ones that have a separate module exclusively related to its movements. Different fore- vs hindlimb patterns are also seen for anatomical network complexity (i.e., complexity in the arrangement of bones and muscles). For instance, the human hindlimb is as complex as that of chimpanzees but the human forelimb is less complex than in Pan. Importantly, in contrast to the analysis of morphological integration using morphometric approaches, network analyses do not support the prediction that forelimb and hindlimb are more dissimilar in species with functionally divergent limbs such as bipedal humans

The incompatible behaviour of gold in reduced magmas : a working hypothesis

O ouro apresenta comportamento distinto ao longo da evolução magmática, de acordo com a fO2 do magma. Em condições oxidantes, caracterizadas pela presença de magnetite como a principal fase de óxido de Fe-Ti, a concentração de ouro em rochas plutóinicas diminui com a diferenciação. No entanto, em condições redutoras, caracterizadas pela predominância de ilmenite, a concentração de ouro em rochas plutónicas aumenta com a diferenciação. Neste trabalho, comparam se as estruturas das fases de óxido de Fe-Ti (magnetite e ilmenite) com os possíveis iões de ouro (auroso, Au+; e aurico, Au3+). É formulada a hipótese de sob condições mais oxidantes ocorrer ouro aurico que, devido a ter um raio iónico similar ao ferro ferroso e, até certo ponto, férrico, é facilmente incorporado na magnetite que vai cristalizando, pelo que a magnetite actua como um sumidouro para o ouro e leva à sua progressiva remoção do magma. Sob condições mais redutoras, o único ião de ouro presente é o auroso que, devido ao seu grande raio iónico, não é passível de ser incorporado na ilmenite (nem possivelmente na magnetite). Deste modo, o ouro comporta se como um elemento incompatível e tende a acumular se em fluidos tardios, ficando disponível para levar à formação de mineralizações auríferas