42 research outputs found

    Eugenia membranifolia: a long-forgotten Brazilian Atlantic rainforest Myrtaceae

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    Eugenia membranifolia Niedenzu, a forgotten name in Brazilian Myrtaceae and presently known only from one isotype, is reported as the correct name for most of the gatherings until now identified as Eugenia bocainensis. We provide a detailed description of E. membranifolia with comments on its distribution, ecology and conservation status, and compare it with E. bocainensis. Key words: Eugenia bocainensis, IUCN Red List, Myrteae, Phyllocaly

    Optimization of MKID Noise Performance Via Readout Technique for Astronomical Applications

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    Detectors employing superconducting microwave kinetic inductance detectors (MKIDs) can be read out by measuring changes in either the resonator frequency or dissipation. We will discuss the pros and cons of both methods, in particular, the readout method strategies being explored for the Multiwavelength Sub/millimeter Inductance Camera (MUSIC) to be commissioned at the CSO in 2010. As predicted theoretically and observed experimentally, the frequency responsivity is larger than the dissipation responsivity, by a factor of 2-4 under typical conditions. In the absence of any other noise contributions, it should be easier to overcome amplifier noise by simply using frequency readout. The resonators, however, exhibit excess frequency noise which has been ascribed to a surface distribution of two-level fluctuators sensitive to specific device geometries and fabrication techniques. Impressive dark noise performance has been achieved using modified resonator geometries employing interdigitated capacitors (IDCs). To date, our noise measurement and modeling efforts have assumed an onresonance readout, with the carrier power set well below the nonlinear regime. Several experimental indicators suggested to us that the optimal readout technique may in fact require a higher readout power, with the carrier tuned somewhat off resonance, and that a careful systematic study of the optimal readout conditions was needed. We will present the results of such a study, and discuss the optimum readout conditions as well as the performance that can be achieved relative to BLIP

    Observations of H1426+428 with HEGRA -- Observations in 2002 and reanalysis of 1999&2000 data

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    The HEGRA system of imaging air Cherenkov telescopes has been used to observe the BL Lac object H1426+428 (z=0.129z=0.129) for 217.5 hours in 2002. In this data set alone, the source is detected at a confidence level of 5.3 σ5.3~\sigma, confirming this object as a TeV source. The overall flux level during the observations in 2002 is found to be a factor of 2.5\approx 2.5 lower than during the previous observations by HEGRA in 1999&2000. A new spectral analysis has been carried out, improving the signal-to-noise ratio at the expense of a slightly increased systematic uncertainty and reducing the relative energy resolution to ΔE/E12\Delta E/E\le 12 % over a wide range of energies. The new method has also been applied to the previously published data set taken in 1999 and 2000, confirming the earlier claim of a flattening of the energy spectrum between 1 and 5 TeV. The data set taken in 2002 shows again a signal at energies above 1 TeV. We combine the energy spectra as determined by the CAT and VERITAS groups with our reanalyzed result of the 1999&2000 data set and apply a correction to account for effects of absorption of high energy photons on extragalactic background light in the optical to mid infrared band. The shape of the inferred source spectrum is mostly sensitive to the characteristics of the extragalactic background light between wavelengths of 1 and 15~μ\mumComment: 12 pages, 4 Figures, submitted to A&

    Nomenclatural note on Eugenia maritima and Myrcia polyantha (Myrtaceae)

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    Volume: 2015-30Start Page: 1End Page:

    Correction: "A note on Eugenia maritima and Myrcia polyantha (Myrtaceae)."

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    Volume: 2015-54Start Page: 1End Page:

    Suprageneric phylogenetics of Myrteae, the generically richest tribe in Myrtaceae (Myrtales)

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    To clarify relationships within the predominantly Neotropical and exclusively fleshy-fruited Myrteae (49 genera and c. 2,500 species), we provide a phylogenetic hypothesis for evolutionary relationships between 31 of these genera by analyzing nuclear ITS and ETS ribosomal DNA, and plastid psbA-trnH and matK DNA sequences from 75 Myrteae species and 13 outgroup taxa using parsimony and Bayesian inference. Four morphological characters are epitomized on the resulting trees, and biogeographical analyses are also performed. Myrteae are monophyletic, comprising seven clades plus two isolated taxa of unclear relationships. Morphological characters exhibit homoplasy, although in combination are useful for clade diagnosis. Biogeographical analyses are inconclusive regarding the ancestral area of the tribe, but South American colonization before northern radiation via the Andes appears likely. The largest genera, Eugenia and Myrcia s.l., have western and southeastern South American origins, respectively
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