5,136 research outputs found
New looks at and for Onespa, Buzyges, and Librita (Lepidoptera: Hesperiidae: Hesperiinae), with new combinations and descriptions of a new genus and six new species
Thirteen species of skippers (six newly described; Lepidoptera: Hesperiidae: Hesperiinae: Hesperiini) from higher elevations of Mexico and Central America are reviewed. These are included in four genera (one newly described), some with proposed new combinations. Onespa Steinhauser, 1974, originally described as monotypic, is shown to include three species in addition to its type species, Onespa nubis Steinhauser, 1974. One of these, Atrytone gala Godman, 1900, that has been misplaced in several genera since its description, represents a new combination. The other two species, distributed in montane habitats in northwestern Mexico and in Costa Rica, are described as new. Buzyges Godman, 1900, distributed in Mexico and Central America and also formerly considered monotypic, is shown to embrace four species. Besides the type species, Buzyges idothea Godman, 1900, two species long placed in Poanes Scudder, 1872, Pamphila rolla Mabille, 1883, and Poanes benito Freeman, 1979, are included as new combinations. Another species, known only from Costa Rica, is described as new. These are united by several superficial characters, but especially by genital morphology of both sexes. Librita Evans, 1955, was described to include three species of which one, Librita raspa Evans, 1955, was subsequently removed. Augiades heras Godman, 1900 is here also removed from Librita and placed in a new genus with three previously undescribed species. This completes the disintegration of Librita, which is now monotypic. The four genera, although exhibiting similarities suggesting potential alliance, differ in their unique combinations of several superficial and genital traits from each other and other hesperiine skippers
The type of Copaeodes chromis Skinner, 1919 (Lepidoptera: Hesperiidae: Hesperiinae)
The holotype of Copaeodes chromis Skinner, 1919 (Lepidoptera: Hesperiidae), housed at the Carnegie Museum of Natural History, is a typical specimen of Zariaspes mythecus Godman, 1900
Briefing: UK Ministry of Defence Force Protection Engineering Programme
The Defence Science and Technology Laboratory sponsored, QinetiQ-led Force Protection Engineering Research Programme has two main strands, applied and underpinning research. The underpinning strand is led by Blastech Ltd. One focus of this research is into the response of geomaterials to threat loading. The programme on locally won fill is split into four main characterisation strands: high-stress (GPa) static pressure–volume; medium-rate pressure–volume (split Hopkinson bar); high-rate (flyer plate) pressure–volume; and unifying modelling research at the University of Sheffield, which has focused on developing a high-quality dataset for locally won fill in low and medium strain rates. With the test apparatus at Sheffield well-controlled tests can be conducted at both high strain rate and pseudo-static rates up to stress levels of 1 GPa. The University of Cambridge has focused on using one-dimensional shock experiments to examine high-rate pressure–volume relationships. Both establishments are examining the effect of moisture content and starting density on emergent rate effects. Blastech Ltd has been undertaking carefully controlled fragment impact experiments, within the dataspace developed by the Universities of Sheffield and Cambridge. The data from experiments are unified by the QinetiQ-led modelling team, to predict material behaviour and to derive a scalable locally won fill model for use in any situation
An annotated list of the Lepidoptera of Honduras
A biodiversity inventory of the Lepidoptera of Pico Bonito National Park and vicinity, in the Department of Atlantida of northern Honduras, was initiated in 2009 to obtain baseline data. We present a revised checklist of Honduran butterfly species (updated from the initial 1967 lists), as well as the first comprehensive list of Honduran moths. Our updated list includes 550 species of Papilionoidea, 311 Hesperioidea, and 1,441 moth species
Quantitative characterization of viscoelastic behavior in tissue-mimicking phantoms and ex vivo animal tissues.
Viscoelasticity of soft tissue is often related to pathology, and therefore, has become an important diagnostic indicator in the clinical assessment of suspect tissue. Surgeons, particularly within head and neck subsites, typically use palpation techniques for intra-operative tumor detection. This detection method, however, is highly subjective and often fails to detect small or deep abnormalities. Vibroacoustography (VA) and similar methods have previously been used to distinguish tissue with high-contrast, but a firm understanding of the main contrast mechanism has yet to be verified. The contributions of tissue mechanical properties in VA images have been difficult to verify given the limited literature on viscoelastic properties of various normal and diseased tissue. This paper aims to investigate viscoelasticity theory and present a detailed description of viscoelastic experimental results obtained in tissue-mimicking phantoms (TMPs) and ex vivo tissues to verify the main contrast mechanism in VA and similar imaging modalities. A spherical-tip micro-indentation technique was employed with the Hertzian model to acquire absolute, quantitative, point measurements of the elastic modulus (E), long term shear modulus (η), and time constant (τ) in homogeneous TMPs and ex vivo tissue in rat liver and porcine liver and gallbladder. Viscoelastic differences observed between porcine liver and gallbladder tissue suggest that imaging modalities which utilize the mechanical properties of tissue as a primary contrast mechanism can potentially be used to quantitatively differentiate between proximate organs in a clinical setting. These results may facilitate more accurate tissue modeling and add information not currently available to the field of systems characterization and biomedical research
An annotated list of the Lepidoptera of Honduras
A biodiversity inventory of the Lepidoptera of Pico Bonito National Park and vicinity, in the Department of Atlantida of northern Honduras, was initiated in 2009 to obtain baseline data. We present a revised checklist of Honduran butterfly species (updated from the initial 1967 lists), as well as the first comprehensive list of Honduran moths. Our updated list includes 550 species of Papilionoidea, 311 Hesperioidea, and 1,441 moth species
Elucidation of the anaerobic pathway for the corrin component of cobalamin (vitamin B12)
It has been known for the past 20 years that two pathways exist in nature for the de novo biosynthesis of the coenzyme form of vitamin B12, adenosylcobalamin, representing aerobic and anaerobic routes. In contrast to the aerobic pathway, the anaerobic route has remained enigmatic because many of its intermediates have proven technically challenging to isolate, because of their inherent instability. However, by studying the anaerobic cobalamin biosynthetic pathway in Bacillus megaterium and using homologously overproduced enzymes, it has been possible to isolate all of the intermediates between uroporphyrinogen III and cobyrinic acid. Consequently, it has been possible to detail the activities of purified cobinamide biosynthesis (Cbi) proteins CbiF, CbiG, CbiD, CbiJ, CbiET, and CbiC, as well as show the direct in vitro conversion of 5-aminolevulinic acid into cobyrinic acid using a mixture of 14 purified enzymes. This approach has resulted in the isolation of the long sought intermediates, cobalt-precorrin-6A and -6B and cobalt-precorrin-8. EPR, in particular, has proven an effective technique in following these transformations with the cobalt(II) paramagnetic electron in the dyz orbital, rather than the typical dz2. This result has allowed us to speculate that the metal ion plays an unexpected role in assisting the interconversion of pathway intermediates. By determining a function for all of the pathway enzymes, we complete the tool set for cobalamin biosynthesis and pave the way for not only enhancing cobalamin production, but also design of cobalamin derivatives through their combinatorial use and modification
Solution structure of a bacterial microcompartment targeting peptide and its application in the construction of an ethanol bioreactor
Targeting of proteins to bacterial microcompartments (BMCs) is mediated by an 18-amino-acid peptide sequence. Herein, we report the solution structure of the N-terminal targeting peptide (P18) of PduP, the aldehyde dehydrogenase associated with the 1,2-propanediol utilization metabolosome from Citrobacter freundii. The solution structure reveals the peptide to have a well-defined helical conformation along its whole length. Saturation transfer difference and transferred NOE NMR has highlighted the observed interaction surface on the peptide with its main interacting shell protein, PduK. By tagging both a pyruvate decarboxylase and an alcohol dehydrogenase with targeting peptides, it has been possible to direct these enzymes to empty BMCs in vivo and to generate an ethanol bioreactor. Not only are the purified, redesigned BMCs able to transform pyruvate into ethanol efficiently, but the strains containing the modified BMCs produce elevated levels of alcohol
VLA-ANGST: A high-resolution HI Survey of Nearby Dwarf Galaxies
We present the "Very Large Array survey of Advanced Camera for Surveys Nearby
Galaxy Survey Treasury galaxies (VLA-ANGST)." VLA-ANGST is a National Radio
Astronomy Observatory Large Program consisting of high spectral (0.6-2.6 km/s)
and spatial (~6") resolution observations of neutral, atomic hydrogen (HI)
emission toward 35 nearby dwarf galaxies from the ANGST survey. ANGST is a
systematic HST survey to establish a legacy of uniform multi-color photometry
of resolved stars for a volume-limited sample of nearby galaxies (D\lesssim4
Mpc). VLA-ANGST provides VLA HI observations of the sub-sample of ANGST
galaxies with recent star formation that are observable from the northern
hemisphere and that were not observed in the "The HI Nearby Galaxy Survey"
(THINGS). The overarching scientific goal of VLA-ANGST is to investigate
fundamental characteristics of the neutral interstellar medium (ISM) of dwarf
galaxies. Here we describe the VLA observations, the data reduction, and the
final VLA-ANGST data products. We present an atlas of the integrated HI maps,
the intensity-weighted velocity fields, the second moment maps as a measure for
the velocity dispersion of the HI, individual channel maps, and integrated HI
spectra for each VLA-ANGST galaxy. We closely follow the observational setup
and data reduction of THINGS to achieve comparable sensitivity and angular
resolution. A major difference, however, is the high velocity resolution of the
VLA-ANGST observations (0.65 and 1.3km/s for the majority of the galaxies). The
VLA-ANGST data products are made publicly available at:
https://science.nrao.edu/science/surveys/vla-angst. With available star
formation histories from resolved stellar populations and lower resolution
ancillary observations from the FIR to the UV, VLA-ANGST will enable detailed
studies of the relationship between the ISM and star formation in dwarf
galaxies on a ~100 pc scale.Comment: 64 figures, grouped into 32. 115 pages, accepted for publication in
the Astronomical Journa
The Formation of Kiloparsec-scale HI Holes in Dwarf Galaxies
The origin of kpc-scale holes in the atomic hydrogen (H i) distributions of some nearby dwarf irregular galaxies
presents an intriguing problem. Star formation histories (SFHs) derived from resolved stars give us the unique
opportunity to study past star-forming events that may have helped shape the currently visible Hi distribution. Our
sample of five nearby dwarf irregular galaxies spans over an order of magnitude in both total Hi mass and absolute
B-band magnitude and is at the low-mass end of previously studied systems. We use Very Large Array Hi line
data to estimate the energy required to create the centrally dominant hole in each galaxy. We compare this energy estimate to the past energy released by the underlying stellar populations computed from SFHs derived from data taken with the Hubble Space Telescope. The inferred integrated stellar energy released within the characteristic ages exceeds our energy estimates for creating the holes in all cases, assuming expected efficiencies. Therefore, it appears that stellar feedback provides sufficient energy to produce the observed holes. However, we find no obvious signature of single star-forming events responsible for the observed structures when comparing the global SFHs of each galaxy in our sample to each other or to those of dwarf irregular galaxies reported in the literature. We also fail to find evidence of a central star cluster in FUV or Hα imaging. We conclude that large Hi holes are likely formed from multiple generations of star formation and only under suitable interstellar medium conditions
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