1,128 research outputs found
Denker Rhinotomy for Inverted Papilloma of the Nose and Paranasal Sinuses
Inverted papilloma of the nose and paranasal sinuses is an unusual benign neoplasm that has the propensity for local tissue destruction and an association with malignant degeneration. The tumor represents an inverted growth of epithelium rather than outward proliferation. It most commonly arises from the lateral nasal wall with growth into the nose and paranasal sinuses and only rarely originates from the septum. Presenting symptoms are usually unilateral nasal obstruction and clear rhinorrhea. Surgical excision is the recommended treatment though the aggressiveness ofthe approach has varied. Transnasal local excision has been associated with a high recurrence rate. Lateral rhinotomy with removal of the lateral nasal wall and wide local excision has a low recurrence rate and has been the recommended treatment by most authors since 1980. However, the poor cosmetic results in some patients due to the visible external scar is especially undesirable in young females. We present a series of 23 patients treated over a ten-year period. Fifteen underwent a Denker rhinotomy and medial maxillectomy through a sublabial approach without an external incision. The recurrence rate in our group is 2 7% with a mean 4.7 year follow-up. This recurrence rate lies between that reported for lateral rhinotomy and local transnasal excision
Nuanced and Timely: Capturing Collections Feedback at Point of Use
While libraries are using increasingly sophisticated metrics to determine electronic resourceās usefulness, impact, and cost effectiveness, much of these data reflect past usage. More nuanced information is still needed to guide collection managersā decisions about which content to purchase, borrow, or deselect. To fill this gap, librarians at Oregon State University Libraries and Press and The Ohio State University Libraries are testing the utility of a pop-up survey to gather patron feedback at their point of use. By building an open-source application that inserts a survey between a citation and the full text, librarians are better positioned to capture usersā real-time reasons for selecting a given resource. Usage data can then be linked to qualitative information through questions such as whether a resource is being used for research or teaching; whether a user considers the journal core to their project; or even, if the resource is being used in class or with a student. Inspired by MINES for LibrariesĀ® this application was created to understand e-resource use beyond clicks. The authors discuss how the application works, whether users responded to the pop-up survey as expected, and other preliminary findings
Electron-Phonon Interactions in C-derived Molecular Solids
We present {\it ab initio} density-functional calculations of molecular
solids formed from C-derived closed-shell fullerenes. Solid
CH is found to bind weakly and exhibits many of the electronic
structure features of solid C with an enhanced electron-phonon
interaction potential. We show that chemical doping of this structure is
feasible, albeit more restrictive than its C counterpart, with an
estimated superconducting transition temperature exceeding those of the
alkali-doped C solids.Comment: Lower quality postscript file for Figure 1 is used in the manuscript
in order to meet submission quota for pre-print server. Higher quality
postscript file available from author: [email protected] This article has
been updated to reflect changes incorporated during the peer review process.
It is published in PRB 70, 140504(R) 200
Improving the Phosphorus Efficiency of Temperate Australian Pastures
Phosphorus (P) is a key input necessary for high production in many temperate, grass-legume pasture systems in Australia because the pastures are situated on P-deficient and moderate to highly P-sorbing soils. A consequence of P-sorption in these soils is that much more P must be applied as fertiliser than will be exported in animal products. The P balance efficiency (PBE=100*Pexport/Pinputs) of grazing enterprises (e.g. wool, meat, milk and live animal export) is about 10-30% and compares poorly with some other agricultural enterprises (e.g. 45-54% for grain production; McLaughlin et al. 1992; Weaver and Wong 2011). P accumulates in these soils when they are fertilised as a result of phosphate reactions with Ca and/or Al and Fe oxides, and P incorporation into resistant organic materials (McLaughlin et al. 2011). Some P in grazed fields is also accumulated in animal camps. The net rate of P accumulation in soil (and in grazed fields as a whole) is related to the concentration of plant-available P in the soil. Operating grazing systems at lower plant-available P levels should help to slow P accumulation and result in more effective use of P fertiliser (Simpson et al. 2010; Simpson et al. 2011). Because the P requirement of grass-legume pastures is usually set by the high P requirements of the legume (Hill et al. 2005), we commenced a study to quantify the P requirements of a range of legumes to determine whether productive, lower P-input grazing systems can be developed. We are also screening subterranean clover, the most widely used pasture legume in temperate Australia, for root traits related to P efficiency. Here we report early findings from the establishment year of a field experiment to determine the P requirement of several alternative temperate legumes
Survey of X-rays from Massive Stars Observed at High Spectral Resolution with Chandra
Identifying trends between observational data and the range of physical
parameters of massive stars is a critical step to the still-elusive full
understanding of the source, structure, and evolution of X-ray emission from
the stellar winds, requiring a substantial sample size and systematic analysis
methods. The \emph{Chandra} data archive as of 2022 contains 37 high resolution
spectra of O, B, and WR stars, observed with the \emph{Chandra}/HETGS and of
sufficient quality to fit the continua and emission line profiles. Using a
systematic approach to the data analysis, we explore morphological trends in
the line profiles (i.e., O, Ne, Mg, Si) and find that the centroid offsets of
resolved lines versus wavelength can be separated in three empirically-defined
groups based on the amount of line broadening and centroid offset. Using
\ion{Fe}{17} (15.01 \AA, 17.05 \AA) and \ion{Ne}{10} (12.13 \AA) lines
which are prevalent among the sample stars, we find a well-correlated linear
trend of increasing Full Width Half Maximum (FWHM) with faster wind terminal
velocity. The H-like/He-like total line flux ratio for strong lines displays
different trends with spectral class depending on ion species. Some of the
sources in our sample have peculiar properties (e.g., magnetic and
Cas-analogue stars) and we find that these sources stand out as outliers from
more regular trends. Finally, our spectral analysis is presented summarily in
terms of X-ray spectral energy distributions in specific luminosity for each
source, plus tables of line identifications and fluxes.Comment: 78 pages, 46 figures, 41 tables, Accepted for publication in Ap
Very Shallow Water Bathymetry Retrieval from Hyperspectral Imagery at the Virginia Coast Reserve (VCR\u2707) Multi-Sensor Campaign
A number of institutions, including the Naval Research Laboratory (NRL), have developed look up tables for remote retrieval of bathymetry and in-water optical properties from hyperspectral imagery (HSI) [6]. For bathymetry retrieval, the lower limit is the very shallow water case (here defined as \u3c 2m), a depth zone which is not well resolved by many existing bathymetric LIDAR sensors, such as SHOALS [4]. The ability to rapidly model these shallow water depths from HSI directly has potential benefits for combined HSI/LIDAR systems such as the Compact Hydrographic Airborne Rapid Total Survey (CHARTS) [10]. In this study, we focused on the validation of a near infra-red feature, corresponding to a local minimum in absorption (and therefore a local peak in reflectance), which can be correlated directly to bathymetry with a high degree of confidence. Compared to other VNIR wavelengths, this particular near-IR feature corresponds to a peak in the correlation with depth in this very shallow water regime, and this is a spectral range where reflectance depends primarily on water depth (water absorption) and bottom type, with suspended constituents playing a secondary role
Transition-Transversion Bias Is Not Universal: A Counter Example from Grasshopper Pseudogenes
Comparisons of the DNA sequences of metazoa show an excess of transitional over transversional substitutions. Part of this bias is due to the relatively high rate of mutation of methylated cytosines to thymine. Postmutation processes also introduce a bias, particularly selection for codon-usage bias in coding regions. It is generally assumed, however, that there is a universal bias in favour of transitions over transversions, possibly as a result of the underlying chemistry of mutation. Surprisingly, this underlying trend has been evaluated only in two types of metazoan, namely Drosophila and the Mammalia. Here, we investigate a third group, and find no such bias. We characterize the point substitution spectrum in Podisma pedestris, a grasshopper species with a very large genome. The accumulation of mutations was surveyed in two pseudogene families, nuclear mitochondrial and ribosomal DNA sequences. The cytosine-guanine (CpG) dinucleotides exhibit the high transition frequencies expected of methylated sites. The transition rate at other cytosine residues is significantly lower. After accounting for this methylation effect, there is no significant difference between transition and transversion rates. These results contrast with reports from other taxa and lead us to reject the hypothesis of a universal transition/transversion bias. Instead we suggest fundamental interspecific differences in point substitution processes
Resonant transport and electrostatic effects in single-molecule electrical junctions
In this contribution we demonstrate structural control over a transport resonance in HS(CH2)n[1,4 āC6H4](CH2)nSH (n = 1, 3, 4, 6) metal-molecule-metal junctions, fabricated and tested using the scanning
tunnelingmicroscopy-based I (z)method. The Breit-Wigner resonance originates from one of the arene Ļ-bonding orbitals, which sharpens and moves closer to the contact Fermi energy as n increases. Varying the number of methylene groups thus leads to a very shallow decay of the conductance with the length of the molecule. We demonstrate that the electrical behavior observed here can be straightforwardly rationalized by analyzing the effects caused by the electrostatic balance created at the metal-molecule interface. Such resonances offer future prospects in molecular electronics in terms of controlling charge transport over longer distances, and also in single-molecule conductance switching if the resonances can be externally gatedThis research was supported by the EPSRC (Grant No. EP/H035184/1), by MINECO under Grant No. FIS2013-47328, by the European Union structural funds and the Comunidad de Madrid MAD2D-CM Program under Grant. P2013/MIT-2850, and by Generalitat Valenciana under Grant PROMETEO/2012/011
Comparison of electromagnetic and gravitational radiation: What we can learn about each from the other
We compare the nature of electromagnetic fields and gravitational fields in linearized general relativity. We carry out this comparison both mathematically and visually. In particular, the ālines of forceā visualizations of electromagnetism are contrasted with the recently introduced tendex/vortex eigenline technique for visualizing gravitational fields. Specific solutions, visualizations, and comparisons are given for an oscillating point quadrupole source. Among the similarities illustrated are the quasistatic nature of the near fields, the transverse 1/r nature of the far fields, and the interesting intermediate field structures connecting these two limiting forms. Among the differences illustrated are the meaning of field line motion and of the flow of energy
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