4,823 research outputs found

    A new species of bird’s nest fungi: characterisation of Cyathus subglobisporus sp. nov. based on morphological and molecular data

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    Recent collections of bird’s nest fungi (i.e. Crucibulum, Cyathus, Mycocalia, Nidula, and Nidularia species) in northern Thailand resulted in the discovery of a new species of Cyathus, herein described as C. subglobisporus. This species is distinct by a combination of ivory-coloured fruiting bodies covered with shaggy hairs, plications on the inner surface of the peridium and subglobose basidiospores. Phylogenetic analyses based on ITS and LSU ribosomal DNA sequences using neighbour-joining, maximum likelihood and weighted maximum parsimony support Cyathus subglobisporus as a distinct species and sister to a clade containing C. annulatus, C. renweii and C. stercoreus in the Striatum group

    Dispersion Relations for Thermally Excited Waves in Plasma Crystals

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    Thermally excited waves in a Plasma crystal were numerically simulated using a Box_Tree code. The code is a Barnes_Hut tree code proven effective in modeling systems composed of large numbers of particles. Interaction between individual particles was assumed to conform to a Yukawa potential. Particle charge, mass, density, Debye length and output data intervals are all adjustable parameters in the code. Employing a Fourier transform on the output data, dispersion relations for both longitudinal and transverse wave modes were determined. These were compared with the dispersion relations obtained from experiment as well as a theory based on a harmonic approximation to the potential. They were found to agree over a range of 0.9<k<5, where k is the shielding parameter, defined by the ratio between interparticle distance a and dust Debye length lD. This is an improvement over experimental data as current experiments can only verify the theory up to k = 1.5.Comment: 8 pages, Presented at COSPAR '0

    Dyrithiopsis lakefuxianensis gen et sp. nov. from Fuxian Lake, Yunnan, China and notes on the taxonomic confusion surrounding Dyrithium

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    A new taxon with Dyrithium-like characteristics was collected from Lake Fuxian in China. The taxon is typical of the Amphisphaeriaceae in that it has relatively large, ostiolate, immersed ascomata, unitunicate asci with a J+ subapical ring, and brown ascospores. It is similar to Dyrithium in that it has muriform ascospores, but considerable confusion surrounds this genus. In Dyrithium asci are bitunicate and lack a J+ subapical ring, while this was not true of our species. A new genus, Dyrithiopsis, therefore is established to accommodate this new taxon. Details of its anamorph also are provided, based on cultural studies. Parsimony analyses of part of the large-subunit rDNA provide further evidence to support the familial placement of this new genus in the Amphisphaeriaceae. The taxonomic position of Dyrithium also is discussed.published_or_final_versio

    Phylogenetics and evolution of nematode-trapping fungi (Orbiliales) estimated from nuclear and protein coding genes

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    The systematic classification of nematode-trapping fungi is redefined based on phylogenies inferred from sequence analyses of 28S rDNA, 5.8S rDNA and ß-tubulin genes. Molecular data were analyzed with maximum parsimony, maximum likelihood and Bayesian analysis. An emended generic concept of nematode-trapping fungi is provided. Arthrobotrys is characterized by adhesive networks, Dactylellina by adhesive knobs, and Drechslerella by constricting-rings. Phylogenetic placement of taxa characterized by stalked adhesive knobs and non-constricting rings also is confirmed in Dactylellina. Species that produce unstalked adhesive knobs that grow out to form loops are transferred from Gamsylella to Dactylellina, and those that produce unstalked adhesive knobs that grow out to form networks are transferred from Gamsylella to Arthrobotrys. Gamsylella as currently circumscribed cannot be treated as a valid genus. A hypothesis for the evolution of trapping-devices is presented based on multiple gene data and morphological studies. Predatory and nonpredatory fungi appear to have been derived from nonpredatory members of Orbilia. The adhesive knob is considered to be the ancestral type of trapping device from which constricting rings and networks were derived via two pathways. In the first pathway adhesive knobs retained their adhesive material forming simple two-dimension networks, eventually forming complex three-dimension networks. In the second pathway adhesive knobs lost their adhesive materials, with their ends meeting to form nonconstricting rings and they in turn formed constricting rings with three inflated-cells.published_or_final_versio

    The validity of the Distress Thermometer in female partners of men with prostate cancer

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    © 2018 John Wiley & Sons Ltd Female partners of prostate cancer (PCa) survivors experience heightened psychological distress that may be greater than that expressed by PCa patients. However, optimal approaches to detect distressed, or at risk of distress, partners are unclear. This study applied receiver operating characteristics analysis to evaluate diagnostic accuracy, sensitivity and specificity of the Distress Thermometer (DT) compared to widely used measures of general (Hospital Anxiety and Depression Scale) and cancer-specific (Impact of Events Scale-Revised) distress. Participants were partners of men with localised PCa (recruited around diagnosis) about to undergo or had received surgical treatment (N = 189), and partners of men diagnosed with PCa who were 2–4 years post-treatment (N = 460). In both studies, diagnostic utility of the DT overall was not optimal. Although area under the curve scores were acceptable (ranges: 0.71–0.92 and 0.83–0.94 for general and cancer-specific distress, respectively), sensitivity, specificity and optimal DT cut-offs for partner distress varied for general (range: ≄2 to ≄5) and cancer-specific (range: ≄3 to ≄5) distress both across time and between cohorts. Thus, it is difficult to draw firm conclusions about the diagnostic capabilities of the DT for partners or recommend its use in this population. More comprehensive screening measures may be needed to detect partners needing psychological intervention

    The Reality of Stock Market Jumps Diversification

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    We propose a non-parametric procedure for estimating systemic co-jumps and independent idiosyncratic jumps for 35 stock markets, and study news associated with these jumps as reported in Factiva and Bloomberg from 1988 to 2014. Our results suggest that it is important to distinguish between systemic co-jumps and idiosyncratic jumps. We find both types of jumps have important implications for home-bias investors, while idiosyncratic jumps have economically significant impact on portfolios weights for emerging markets. Our news analysis suggests systemic jumps are typically caused by currency crises, sectoral failure, liquidity issues, and deteriorating economic climate, while idiosyncratic jumps are usually caused by political unrest, currency instability, and large firm effects on small economies. In fact, many of the idiosyncratic jumps share the same origin although different stock markets experienced the impact differently at different times

    First Attempt at Spectroscopic Detection of Gravity Modes in a Long-Period Pulsating Subdwarf B Star -- PG 1627+017

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    In the first spectroscopic campaign for a PG 1716 variable (or long-period pulsating subdwarf B star), we succeeded in detecting velocity variations due to g-mode pulsations at a level of 1.0-1.5 km/s.The observations were obtained during 40 nights on 2-m class telescopes in Arizona, South Africa,and Australia. The target,PG1627+017, is one of the brightest and largest amplitude stars in its class.It is also the visible component of a post-common envelope binary.Our final radial velocity data set includes 84 hours of time-series spectroscopy over a time baseline of 53 days. Our derived radial velocity amplitude spectrum, after subtracting the orbital motion, shows three potential pulsational modes 3-4 sigma above the mean noise level, at 7201.0s,7014.6s and 7037.3s.Only one of the features is statistically likely to be real,but all three are tantalizingly close to, or a one day alias of, the three strongest periodicities found in the concurrent photometric campaign. We further attempted to detect pulsational variations in the Balmer line amplitudes. The single detected periodicity of 7209 s, although weak, is consistent with theoretical expectations as a function of wavelength.Furthermore, it allows us to rule out a degree index of l= 3 or l= 5 for that mode. Given the extreme weakness of g-mode pulsations in these stars,we conclude that anything beyond simply detecting their presence will require larger telescopes,higher efficiency spectral monitoring over longer time baselines,improved longitude coverage, and increased radial velocity precision.Comment: 39 pages, 9 figures, 4 tables, ApJ accepted. See postscript for full abtrac
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