16 research outputs found
Phylogenomic analysis of a 55.1 kb 19-gene dataset resolves a monophyletic Fusarium that includes the Fusarium solani Species Complex
Scientific communication is facilitated by a data-driven, scientifically sound taxonomy that considers the end-user¿s needs and established successful practice. In 2013, the Fusarium community voiced near unanimous support for a concept of Fusarium that represented a clade comprising all agriculturally and clinically important Fusarium species, including the F. solani species complex (FSSC). Subsequently, this concept was challenged in 2015 by one research group who proposed dividing the genus Fusarium into seven genera, including the FSSC described as members of the genus Neocosmospora, with subsequent justification in 2018 based on claims that the 2013 concept of Fusarium is polyphyletic. Here, we test this claim and provide a phylogeny based on exonic nucleotide sequences of 19 orthologous protein-coding genes that strongly support the monophyly of Fusarium including the FSSC. We reassert the practical and scientific argument in support of a genus Fusarium that includes the FSSC and several other basal lineages, consistent with the longstanding use of this name among plant pathologists, medical mycologists, quarantine officials, regulatory agencies, students, and researchers with a stake in its taxonomy. In recognition of this monophyly, 40 species described as genus Neocosmospora were recombined in genus Fusarium, and nine others were renamed Fusarium. Here the global Fusarium community voices strong support for the inclusion of the FSSC in Fusarium, as it remains the best scientific, nomenclatural, and practical taxonomic option availabl
Polarized Emission from Interstellar Dust
Observations of far-infrared (FIR) and submillimeter (SMM) polarized
emission are used to study magnetic fields and dust grains in dense
regions on the interstellar medium (ISM). These observations place
constraints on models of molecular clouds, star-formation, grain
alignment mechanisms, and grain size, shape, and composition.
The FIR/SMM polarization is strongly dependent on
wavelength. We have attributed this wavelength dependence to sampling
different grain populations at different temperatures. To date, most
observations of polarized emission have been in
the densest regions of the ISM. Extending these observations to
regions of the diffuse ISM, and to microwave frequencies, will provide
additional tests of grain and alignment models.
An understanding of polarized microwave emission from dust is key to
an accurate measurement of the polarization of the cosmic microwave
background. The microwave polarization spectrum will put limits on the
contributions to polarized emission from spinning dust and vibrating
magnetic dust.
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Large area bismuth absorbers for X-ray microcalorimeters
Two challenges facing the use of large area (2mm×2mm) bismuth absorbers for microcalorimetry are uncertainties in the heat capacity of bismuth and the effects of lateral heat conduction and position dependence due to the absorber's large size. We have measured the heat capacity of three Bi samples to be 0.3−0.6JK−1m−3 at 100mK. These absorbers also exhibit response variations as phonons created by an X-ray event at an absorber edge will take longer to propagate to the thermometer attachment point than those at the absorber center. This effect may degrade the detector's energy resolution if the propagation time is not very short compared to the thermometer time constant. We show that the response of the largest absorber varies by ∼4% across its area
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Design of the second generation XRS detector
Microcalorimeter performance is limited by non-ideal effects that were not included in the standard theory of bolometers and microcalorimeters developed 20 years ago by Mather (Appl. Opt. 21 (1982) 1125). These include the hot-electron effect, absorber decoupling, thermometer non-ohmic behavior, and all related extra noise sources. Models that include these effects have been developed and can be used to optimize the design of microcalorimeters for best performance. The design of the array for the XRS detector on the Astro-E2 satellite was completely optimized based on the required performance and on the characteristics of the materials used. The characteristic heat capacity and thermal conductivity of all the detector components have been measured and the values have been used as input to the models to design the detector geometry for best performance. Mechanical modeling has also been carried out in parallel to ensure the mechanical integrity of the microcalorimeter. We report here the analysis involved in the optimization of the detectors, and the comparison between modeled and measured performance
Far-Infrared Polarimetry of the Interstellar Medium
Polarimetry at far-infrared wavelengths is a key tool for studying physical processes on size scales ranging from interstellar dust grains to entire galaxies. A multi-wavelength continuum polarimeter at these wavelengths will allow studies of thermal dust polarization in an effort to constrain the grains’ physical properties and test grain alignment theory. High spatial resolution (5–30 arcsec) and sensitive observations will measure the influence of magnetic fields on infrared cirrus clouds, the envelopes and disks of YSOs, outflows from both low- and high-mass star forming regions, and the relative strength of magnetic, gravitational, and turbulent effects in star- and cloud-formation
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The next-generation microcalorimeter array of XRS on Astro-E2
The square-format 32-pixel microcalorimeter array at the focal plane of the high-resolution X-ray spectrometer on the Astro-E2 X-ray Observatory is the first of a new generation of silicon-based microcalorimeters. This array has numerous advantages over its predecessor, the bilinear array that was launched on Astro-E. Foremost among its benefits are: (1) the energy resolution is improved by a factor of two at 6keV (now 6eV FWHM), (2) the thermal time constant is a factor of two faster, and (3) each pixel has a Gaussian line response. We will discuss the design changes that have led to these and other advantages
A Perspective on Human Movement Variability With Applications in Infancy Motor Development
Movement variability is considered essential to typical motor development. However, multiple theoretical perspectives and measurement tools have limited interpretation of the importance of movement variability in biological systems. The complementary use of linear and nonlinear measures have recently allowed for the evaluation of not only the magnitude of variability but also the temporal structure of variability. As a result, the theoretical model of optimal movement variability was introduced. The model suggests that the develop-ment of healthy and highly adaptable systems relies on the achievement of an optimal state of variability. Alternatively, abnormal development may be characterized by a narrow range of behaviors, some of which may be rigid, inflexible, and highly predictable or, on the contrary, random, unfocused, and unpredictable. In the present review, this theoretical model is described as it relates to motor development in infancy and specifically the development of sitting posture