On the efficiency of stochastic volume sources for the determination of light meson masses

We investigate the efficiency of single timeslice stochastic sources for the calculation of light meson masses on the lattice as one varies the quark mass. Simulations are carried out with Nf = 2 flavours of non-perturbatively O(a) improved Wilson fermions for pion masses in the range of 450 - 760 MeV. Results for pseudoscalar and vector meson two-point correlation functions computed using stochastic as well as point sources are presented and compared. At fixed computational cost the stochastic approach reduces the variance considerably in the pseudoscalar channel for all simulated quark masses. The vector channel is more affected by the intrinsic stochastic noise. In order to obtain stable estimates of the statistical errors and a more pronounced plateau for the effective vector meson mass, a relatively large number of stochastic sources must be used.Comment: 18 pages, 6 figure

Floral development and floral phyllotaxis in Anaxagorea (Annonaceae)

Background and Aims Anaxagorea is the phylogenetically basalmost genus in the large tropical Annonaceae (custard apple family) of Magnoliales, but its floral structure is unknown in many respects. The aim of this study is to analyse evolutionarily interesting floral features in comparison with other genera of the Annonaceae and the sister family Eupomatiaceae. Methods Live flowers of Anaxagorea crassipetala were examined in the field with vital staining, liquid-fixed material was studied with scanning electron microscopy, and microtome section series were studied with light microscopy. In addition, herbarium material of two other Anaxagorea species was cursorily studied with the dissecting microscope. Key Results Floral phyllotaxis in Anaxagorea is regularly whorled (with complex whorls) as in all other Annonaceae with a low or medium number of floral organs studied so far (in those with numerous stamens and carpels, phyllotaxis becoming irregular in the androecium and gynoecium). The carpels are completely plicate as in almost all other Annonaceae. In these features Anaxagorea differs sharply from the sister family Eupomatiaceae, which has spiral floral phyllotaxis and ascidiate carpels. Flat stamens and the presence of inner staminodes differ from most other Annonaceae and may be plesiomorphic in Anaxagorea. However, the inner staminodes appear to be non-secretory in most Anaxagorea species, which differs from inner staminodes in other families of Magnoliales (Eupomatiaceae, Degeneriacae, Himantandraceae), which are secretory. Conclusions Floral phyllotaxis in Anaxagorea shows that there is no signature of a basal spiral pattern in Annonaceae and that complex whorls are an apomorphy not just for a part of the family but for the family in its entirety, and irregular phyllotaxis is derived. This and the presence of completely plicate carpels in Anaxagorea makes the family homogeneous and distinguishes it from the closest relatives in Magnoliale

PINOCHIA, A NEW GENUS OF APOCYNACEAE, APOCYNOIDEAE FROM THE GREATER ANTILLES, MEXICO AND CENTRAL AMERICA

Pinochia, a new neotropical genus of Apocynaceae, subfamily Apocynoideae, is segregated from Forsteronia, described and illustrated. Four new combinations and a key to the species are provide

A phylogenetic analysis of Apostasioideae (Orchidaceae) based on ITS, trn L-F and mat K sequences

Abstract.: The orchid subfamily Apostasioideae consists of two genera, Apostasia and Neuwiedia. To study the position of Apostasioideae within Orchidaceae and their intra- and intergeneric relationships, a molecular phylogenetic analysis has been conducted on the nuclear ITS region and the two plastid DNA regions trnL-F intron and matK. The two genera traditionally ascribed to Apostasioideae are each monophyletic. In Apostasia, A. nuda, with two stamens and no staminode, is sister to a clade comprising three species characterised by two stamens and one staminode. Within Neuwiedia, maximum parsimony analyses place N. zollingeri as sister to the clade formed by N. borneensis and N. veratrifolia. A family-wide phylogenetic analysis of matK sequences representing all proposed subfamilies of Orchidaceae produced five moderately to well-supported clades. One of these clades, Apostasioideae, is sister to the clade formed by Vanilloideae, Cypripedioideae, Orchidoideae and Epidendroideae. High transition-transversion ratio and the absence of stop codons in the individual sequences suggest that matK is at the transition from a possibly functional gene to a pseudogene in Apostasioideae, contrary to what is found in some other groups of Orchidacea

A new species of Mandevilla (Apocynaceae) from limestone outcrops in Central Brazil with a short note on the occurrence of geophytes in rauvolfioids and apocynoids

Mandevilla calcicola, endemic to limestone formations in Goias state, Brazil, is described. A key and photos for all Mandevilla species reported in Goias and Distrito Federal, Brazil, are included. This new species is assessed as Critically Endangered (CR). A short note on the occurrence of geophytes in rauvolfioids and apocynoids (focused on Mandevilla) and its taxonomic value is included

A revised classification of the Apocynaceae s.l.

The Asclepiadaceae, as traditionally defined, have repeatedly been shown to be an apomorphic derivative of the Apocynaceae. It has often been recommended that the Asclepiadaceae be subsumed within the Apocynaceae in order to make the latter monophyletic. To date, however, no comprehensive, unified classification has been established. Here we provide a unified classification for the Apocynaceae, which consists of 424 genera distributed among five subfamilies: Rauvolfioideae, Apocynoideae, Periplocoideae, Secamonoideae, and Asclepiadoideae. Keys to the subfamilies and tribes are provided, with lists of genera that (as far as we have been able to ascertain) are recognized in each trib

A phylogenetic analysis of Apostasioideae (Orchidaceae) based on ITS, trn L-F and mat K sequences

The orchid subfamily Apostasioideae consists of two genera, Apostasia and Neuwiedia . To study the position of Apostasioideae within Orchidaceae and their intra- and intergeneric relationships, a molecular phylogenetic analysis has been conducted on the nuclear ITS region and the two plastid DNA regions trn L-F intron and mat K. The two genera traditionally ascribed to Apostasioideae are each monophyletic. In Apostasia , A. nuda , with two stamens and no staminode, is sister to a clade comprising three species characterised by two stamens and one staminode. Within Neuwiedia , maximum parsimony analyses place N. zollingeri as sister to the clade formed by N. borneensis and N. veratrifolia . A family-wide phylogenetic analysis of mat K sequences representing all proposed subfamilies of Orchidaceae produced five moderately to well-supported clades. One of these clades, Apostasioideae, is sister to the clade formed by Vanilloideae, Cypripedioideae, Orchidoideae and Epidendroideae. High transition-transversion ratio and the absence of stop codons in the individual sequences suggest that mat K is at the transition from a possibly functional gene to a pseudogene in Apostasioideae, contrary to what is found in some other groups of Orchidaceae.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41641/1/606_2004_Article_133.pd

Universality of Level Spacing Distributions in Classical Chaos

We suggest that random matrix theory applied to a classical action matrix can be used in classical physics to distinguish chaotic from non-chaotic behavior. We consider the 2-D stadium billiard system as well as the 2-D anharmonic and harmonic oscillator. By unfolding of the spectrum of such matrix we compute the level spacing distribution, the spectral auto-correlation and spectral rigidity. We observe Poissonian behavior in the integrable case and Wignerian behavior in the chaotic case. We present numerical evidence that the action matrix of the stadium billiard displays GOE behavior and give an explanation for it. The findings present evidence for universality of level fluctuations - known from quantum chaos - also to hold in classical physics