Comparative morphology of female flowers and systematics in Geonomeae (Arecaceae)

Abstract.: Female floral structure is compared in Geonomeae (Arecaceae). A perianth is formed by two alternate whorls of three basally congenitally united and imbricate sepals and three basally congenitally united and apically valvate petals. A sterile androecium is formed by a variable number of staminodes, which are united into a tube. The gynoecium shows three more or less equally developed carpels or is pseudomonomerous (Geonoma). The single anatropous ovule per carpel is median, either basal or at mid-height of the ovary. A septal nectary is present at the base and mid-height of the ovaries and exits at different levels of the ovary. Carpels in pseudomonomerous gynoecia seem to be "basistylous”, but the styles are more lateral or apical in gynoecia with all three carpels equally developed. Stigmas expose unicellular or multicellular (Welfia) papillae at anthesis. Pollen tube transmitting tracts and a compitum are present in the ventral slits of the postgenitally united styles. Floral structure in Geonomeae is compared with other Arecaceae, especially Arecoideae, in a morphological and systematic contex

Floral structure of Kirkia (Kirkiaceae) and its position in Sapindales

BACKGROUND AND AIMS: The monogeneric Kirkiaceae (Sapindales) were formerly placed as Kirkioideae in Simaroubaceae. However, recent molecular phylogenetic studies indicate that they are not in Simaroubaceae and they appear to be sister to the clade of Anacardiaceae plus Burseraceae. Such affinity was never considered or discussed since the first description of Kirkia. The present study is the first detailed analysis of the floral structure of a representative of Kirkiaceae and the first comparison with other sapindalean families, especially Anacardiaceae and Burseraceae. METHODS: Floral structure of Kirkia wilmsii was studied using transversal and longitudinal microtome section series, scanning electron microscopy and light microscopy. KEY RESULTS: The flowers of Kirkia wilmsii are morphologically bisexual but functionally unisexual. They are polysymmetric, isomerous (tetramerous) and haplostemonous. The ovary is syncarpous and entirely synascidiate. The floral apex forms a hemispherical protrusion on top of the ovary. The styles are free but postgenitally united and apically form a stigmatic head with a compitum. Each carpel is uniovulate (biovulate in a few other species) and ovules are crassinucellar, bitegmic and slightly campylotropous. The micropyle is formed by both integuments and is unusually long. The unusual two radially disposed locules in each carpel in the former genus Pleiokirkia can be explained developmentally by the two offset and tightly contiguous lateral placentae. CONCLUSIONS: Paralleling the molecular results, a suite of floral features supports the position of Kirkiaceae close to the Anacardiaceae-Burseraceae clade, and not in Simaroubacea

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

Comparative morphology of female flowers and systematics in Geonomeae (Arecaceae)

Female floral structure is compared in Geonomeae (Arecaceae). A perianth is formed by two alternate whorls of three basally congenitally united and imbricate sepals and three basally congenitally united and apically valvate petals. A sterile androecium is formed by a variable number of staminodes, which are united into a tube. The gynoecium shows three more or less equally developed carpels or is pseudomonomerous (Geonoma). The single anatropous ovule per carpel is median, either basal or at mid-height of the ovary. A septal nectary is present at the base and mid-height of the ovaries and exits at different levels of the ovary. Carpels in pseudomonomerous gynoecia seem to be "basistylous”, but the styles are more lateral or apical in gynoecia with all three carpels equally developed. Stigmas expose unicellular or multicellular (Welfia) papillae at anthesis. Pollen tube transmitting tracts and a compitum are present in the ventral slits of the postgenitally united styles. Floral structure in Geonomeae is compared with other Arecaceae, especially Arecoideae, in a morphological and systematic contex

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

Primitive computations in speech processing

Previous research suggests that artificial-language learners exposed to quasi-continuous speech can learn that the first and the last syllables of words have to belong to distinct classes (e.g., Endress & Bonatti, 2007; Peña, Bonatti, Nespor, & Mehler, 2002). The mechanisms of these generalizations, however, are debated. Here we show that participants learn such generalizations only when the crucial syllables are in edge positions (i.e., the first and the last), but not when they are in medial positions (i.e., the second and the fourth in pentasyllabic items). In contrast to the generalizations, participants readily perform statistical analyses also in word middles. In analogy to sequential memory, we suggest that participants extract the generalizations using a simple but specific mechanism that encodes the positions of syllables that occur in edges. Simultaneously, they use another mechanism to track the syllable distribution in the speech streams. In contrast to previous accounts, this model explains why the generalizations are faster than the statistical computations, require additional cues, and break down under different conditions, and why they can be performed at all. We also show that that similar edge-based mechanisms may explain many results in artificial-grammar learning and also various linguistic observations

Characterising the CI and CI-like carbonaceous chondrites using thermogravimetric analysis and infrared spectroscopy

The CI and CI-like chondrites provide a record of aqueous alteration in the early solar system. However, the CI-like chondrites differ in having also experienced a late stage period of thermal metamorphism. In order to constrain the nature and extent of the aqueous and thermal alteration, we have investigated the bulk mineralogy and abundance of H2O in the CI and CI-like chondrites using thermogravimetric analysis and infrared spectroscopy. The CI chondrites Ivuna and Orgueil show significant mass loss (28.5–31.8 wt.%) upon heating to 1000 °C due to dehydration and dehydroxylation of abundant phyllosilicates and Fe-(oxy)hydroxides and the decomposition of Fe-sulphides, carbonates and organics. Infrared spectra for Ivuna and Orgueil have a prominent 3-μm feature due to bound −OH/H2O in phyllosilicates and Fe-(oxy)hydroxides and only a minor 11-μm feature from anhydrous silicates. These characteristics are consistent with previous studies indicating that the CI chondrites underwent near-complete aqueous alteration. Similarities in the total abundance of H2O and 3 μm/11 μm ratio suggest that there is no difference in the relative degree of hydration experienced by Ivuna and Orgueil. In contrast, the CI-like chondrites Y-82162 and Y-980115 show lower mass loss (13.8–18.8 wt.%) and contain >50 % less H2O than the CI chondrites. The 3-μm feature is almost absent from spectra of Y-82162 and Y-980115 but the 11-μm feature is intense. The CI-like chondrites experienced thermal metamorphism at temperatures >500 °C that initially caused dehydration and dehydroxylation of phyllosilicates before partial recrystallization back into anhydrous silicates. The surfaces of many C-type asteroids were probably heated through impact metamorphism and/or solar radiation, so thermally altered carbonaceous chondrites are likely good analogues for samples that will be returned by the Hayabusa-2 and OSIRIS-REx missions

Solar System Processes Underlying Planetary Formation, Geodynamics, and the Georeactor

Only three processes, operant during the formation of the Solar System, are responsible for the diversity of matter in the Solar System and are directly responsible for planetary internal-structures, including planetocentric nuclear fission reactors, and for dynamical processes, including and especially, geodynamics. These processes are: (i) Low-pressure, low-temperature condensation from solar matter in the remote reaches of the Solar System or in the interstellar medium; (ii) High-pressure, high-temperature condensation from solar matter associated with planetary-formation by raining out from the interiors of giant-gaseous protoplanets, and; (iii) Stripping of the primordial volatile components from the inner portion of the Solar System by super-intense solar wind associated with T-Tauri phase mass-ejections, presumably during the thermonuclear ignition of the Sun. As described herein, these processes lead logically, in a causally related manner, to a coherent vision of planetary formation with profound implications including, but not limited to, (a) Earth formation as a giant gaseous Jupiter-like planet with vast amounts of stored energy of protoplanetary compression in its rock-plus-alloy kernel; (b) Removal of approximately 300 Earth-masses of primordial gases from the Earth, which began Earth's decompression process, making available the stored energy of protoplanetary compression for driving geodynamic processes, which I have described by the new whole-Earth decompression dynamics and which is responsible for emplacing heat at the mantle-crust-interface at the base of the crust through the process I have described, called mantle decompression thermal-tsunami; and, (c)Uranium accumulations at the planetary centers capable of self-sustained nuclear fission chain reactions.Comment: Invited paper for the Special Issue of Earth, Moon and Planets entitled Neutrino Geophysics Added final corrections for publicatio

First evidence of coherent K+K^{+} meson production in neutrino-nucleus scattering

Neutrino-induced charged-current coherent kaon production, $\nu_{\mu}A\rightarrow\mu^{-}K^{+}A$, is a rare, inelastic electroweak process that brings a $K^+$ on shell and leaves the target nucleus intact in its ground state. This process is significantly lower in rate than neutrino-induced charged-current coherent pion production, because of Cabibbo suppression and a kinematic suppression due to the larger kaon mass. We search for such events in the scintillator tracker of MINERvA by observing the final state $K^+$, $\mu^-$ and no other detector activity, and by using the kinematics of the final state particles to reconstruct the small momentum transfer to the nucleus, which is a model-independent characteristic of coherent scattering. We find the first experimental evidence for the process at $3\sigma$ significance.Comment: added ancillary file with information about the six kaon candidate