5,577 research outputs found
On and Off-diagonal Sturmian operator: dynamic and spectral dimension
We study two versions of quasicrystal model, both subcases of Jacobi
matrices. For Off-diagonal model, we show an upper bound of dynamical exponent
and the norm of the transfer matrix. We apply this result to the Off-diagonal
Fibonacci Hamiltonian and obtain a sub-ballistic bound for coupling large
enough. In diagonal case, we improve previous lower bounds on the fractal
box-counting dimension of the spectrum.Comment: arXiv admin note: text overlap with arXiv:math-ph/0502044 and
arXiv:0807.3024 by other author
Records for Bittacus Hangingflies and Panorpa Scorpionflies (Mecoptera: Bittacidae and Panorpidae) in Florida
We provide new county records for four species of panorpids (Panorpa americana Swederus, Panorpa lugubris Swederus, Panorpa sp. undetermined, and one undescribed species from the Panorpa rufescens Rambur species group) and two species of bittacids (Bittacus pilicornis Westwood, Bittacus punctiger Westwood), and call attention to a previously published county record for another species, Panorpa rufa Gray, in Florida. Additionally, we reject a previously published record for the scorpionfly Panorpa claripennis Hine in Florida, which we overlooked in our 2008 preliminary checklist of Florida mecopterans. The record for P. lugubris in Miami-Dade County is the southernmost record for any panorpid in the continental United States
Preliminary Checklist of the Mecoptera of Florida: Earwigflies, Hangingflies, and Scorpionflies
We provide the first species checklist of Mecoptera indigenous to Florida, based upon preliminary data gathered primarily from specimens housed in the Florida State Collection of Arthropods. There are 11 described and one undescribed species of mecopterans, representing three families, inhabiting the state of Florida. These include the recently discovered meropeid (earwigfly), Merope tuber Newman, four species of bittacids (hangingflies), represented by the genus Bittacus Latreille, and 7 species (one undescribed) of panorpids (scorpionflies), represented by the genus Panorpa Linnaeus. We are not certain if one of these, Bittacus texanus Banks, is indigenous, represents a nonindigenous occurrence, or is simply erroneous. Two of the species on our list, Bittacus stigmaterus Say and Panorpa venosa Westwood, represent first state records and one species, Panorpa floridana Byers, is endemic. Six of the species which have been recorded in Florida, M. tuber, Bittacus punctiger Westwood, Panorpa rufa Gray, Panorpa pachymera Byers, Panorpa lugubris Swederus and P. venosa, represent the southernmost records for these species in the continental United States. Perceived diversity and abundance of mecopteran species in Florida are limited by climate, biogeography, and collection bias
Rediscovery of the Florida Scorpionfly, Panorpa floridana Byers (Mecoptera: Panorpidae)
We describe the rediscovery of the Florida scorpionfly, Panorpa floridana Byers (Mecoptera: Panorpidae), at Gold Head Branch State Park, Clay County, Florida, based upon a single, living, adult specimen photographed on 4 November 2010. The hardcopy photographic prints and electronic digital images of this panorpid are the first vouchers for P. floridana in 28 years, the only observation of a living specimen, and the sixth individual known of this seemingly rare Florida endemic
Roche tomography of cataclysmic variables - V. A high-latitude star-spot on RU Pegasi
We present Roche tomograms of the secondary star in the dwarf nova system RU
Pegasi derived from blue and red arm ISIS data taken on the 4.2-m William
Herschel Telescope. We have applied the entropy landscape technique to
determine the system parameters and obtained component masses of M1 = 1.06
Msun, M2 = 0.96 Msun, an orbital inclination angle of i = 43 degrees, and an
optimal systemic velocity of gamma = 7 km/s. These are in good agreement with
previously published values. Our Roche tomograms of the secondary star show
prominent irradiation of the inner Lagrangian point due to illumination by the
disc and/or bright spot, which may have been enhanced as RU Peg was in outburst
at the time of our observations.We find that this irradiation pattern is
axi-symmetric and confined to regions of the star which have a direct view of
the accretion regions. This is in contrast to previous attempts to map RU Peg
which suggested that the irradiation pattern was non-symmetric and extended
beyond the terminator. We also detect additional inhomogeneities in the surface
distribution of stellar atomic absorption that we ascribe to the presence of a
large star-spot. This spot is centred at a latitude of about 82 degrees and
covers approximately 4 per cent of the total surface area of the secondary. In
keeping with the high latitude spots mapped on the cataclysmic variables AE Aqr
and BV Cen, the spot on RU Peg also appears slightly shifted towards the
trailing hemisphere of the star. Finally, we speculate that early mapping
attempts which indicated non-symmetric irradiation patterns which extended
beyond the terminator of CV donors could possibly be explained by a
superposition of symmetric heating and a large spot.Comment: 14 pages, 10 figures, 3 tables Accepted for publication in Monthly
Notices of the Royal Astronomical Societ
Strength Properties of Preceramic Brazed Joints of a Gold-Palladium Alloy with a Microwave-assisted Oven and Gas/Oxygen Torch Technique
Statement of problem The effect of microwave brazing on the strength properties of dental casting alloys is not yet known. Purpose The purpose of this study was to compare the strength properties of preceramic brazed joints obtained by using a microwave oven and a conventional torch flame for a high noble alloy (Au-Pd). Material and methods A total of 18 tensile bars made of an Au-Pd ceramic alloy were fabricated. Six specimens were cut and joined with a high-fusing preceramic solder in a specially designed microwave oven, and 6 specimens were joined with a conventional natural gas/oxygen torch. The remaining 6 uncut specimens were tested as a control. All the specimens were subjected to testing with a universal testing machine. A 1-way ANOVA was performed for each strength property tested. Results
The tensile strength of the uncut group was the highest (745 ±19 MPa), followed by the microwave group (420 ±68 MPa) and the conventional torch group (348 ±103 MPa) (P Conclusions The microwave heating preceramic solder method demonstrated the excellent tensile strength of an Au-Pd alloy and may be an alternative way of joining alloys when a torch flame is contraindicated
A method for preparing PCR products for restriction-enzyme-directed cloning without enzymic digestion
Etymology of the earwigfly, \u3ci\u3eMerope tuber\u3c/i\u3e Newman (Mecoptera: Meropeidae): Simply dull or just inscrutable?
The naturalist Edward Newman did not provide an etymology for the mecopteran Merope tuber when he described it in 1838. In 1872 Asa Fitch asserted that the genus was named after Merope one of the Pleiades sisters of Greek mythology; however, he provided no reason for his assumption. We researched several etymological alternatives. We concur with Fitch and conclude that Newman did indeed name the genus Merope after the dullest of the Pleiades sisters
A note on a canonical dynamical r-matrix
It is well known that a classical dynamical -matrix can be associated with
every finite-dimensional self-dual Lie algebra \G by the definition
, where \omega\in \G and is the
holomorphic function given by for
z\in \C\setminus 2\pi i \Z^*. We present a new, direct proof of the statement
that this canonical -matrix satisfies the modified classical dynamical
Yang-Baxter equation on \G.Comment: 17 pages, LaTeX2
Microalgae Growth in Physically Pre-Treated Wastewater Generated During Hydraulic Fracturing
Hydraulic fracturing technique frequently used during gas and oil production generates large amounts of wastewaters (WWs). High cost of the conventional techniques used to treat such waters adversely affect their economic feasibility. Hence, novel technologies that will facilitate remediation and subsequent re-use of these WWs are welcomed. In this study, growth profile of four Oklahoma native microalgae (Geitlerinema carotinosum, Komvophoron sp., Pseudanabaena sp., Picochlorum oklahomensis) cultivated in physically pre-treated flowback and produced water generated during hydraulic fracturing were characterized. A mechanical step based on oil removal by an oil skimmer was introduced during pre-treatment. The experimental results demonstrated that all four strains could grow in pre-treated flowback and produced water. Biomass productivity varied significantly with the microalgae strain and type of the WW used in the growth experiments. The best performing strain, cyanobacterium Komvophoron sp., was able to grow with a specific growth rate ranging from 0.03 to 0.18 day-1 depending on the type of WW. The process was capable of removing ammonium and phosphorus with efficiencies up to 99 and 63%, respectively
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