244 research outputs found
Mapping suspended particle and solute concentrations from satellite data
There are no author-identified significant results in this report
Grant and Lee: Victorious American and Vanquished Virginian
Who\u27s the Best General? A favorite around-the-lunch-table diversion of students of military history is a game called Who\u27s the best general. One of its major attractions is that none can unequivocally win or lose, because the criteria for declaring victory are all so subjective that new c...
A Soldier to the Last: Maj. Gen. Joseph Wheeler in Blue and Gray
Joe Wheeler\u27s Cavalry An Unembellished Account Fightin\u27 Joe Wheeler was one of a seemingly endless parade of notable cavalry commanders spawned by the Confederacy during the four years of the Civil War. Many of their biographers, if not most, seem to have fallen victim to biogra...
Sediment pattern correlation with inflow and tidal action
There are no author-identified significant results in this report
Localization of tamoxifen in human breast cancer tumors by MALDI mass spectrometry imaging
Background: Tamoxifen is used in endocrine treatment of breast cancer to inhibit estrogen signaling. A set of stratiâ ed ERâpositive and ERânegative tumor sections was subjected to manual deposition of tamoxifen solution in order to investigate its spatial distribution upon exposure to interaction within thin tissue sections. Methods: The localization of tamoxifen in tumor sections was assessed by matrix assisted laser deposition/ionizaâ tion mass spectrometry imaging. The images of extracted ion maps were analyzed for comparison of signal intensity distributions. Results: The precursor ion of tamoxifen (m/z 372.233) displayed heterogeneous signal intensity distributions in hisâ tological compartments of tumor tissue sections. The levels of tamoxifen in tumor cells compared with stroma were higher in ERâpositive tissues, whereas ERânegative tissue sections showed lower signal intensities in tumor cells. Conclusions: The experimental model was successfully applied on frozen tumor samples allowing for di erentiation between ER groups based on distribution of tamoxifen
Synchronous Optical and Radio Polarization Variability in the Blazar OJ287
We explore the variability and cross-frequency correlation of the flux
density and polarization of the blazar OJ287, using imaging at 43 GHz with the
Very Long Baseline Array, as well as optical and near-infrared polarimetry. The
polarization and flux density in both the optical waveband and the 43 GHz
compact core increased by a small amount in late 2005, and increased
significantly along with the near-IR polarization and flux density over the
course of 10 days in early 2006. Furthermore, the values of the electric vector
position angle (EVPA) at the three wavebands are similar. At 43 GHz, the EVPA
of the blazar core is perpendicular to the flow of the jet, while the EVPAs of
emerging superluminal knots are aligned parallel to the jet axis. The core
polarization is that expected if shear aligns the magnetic field at the
boundary between flows of disparate velocities within the jet. Using variations
in flux density, percentage polarization, and EVPA, we model the inner jet as a
spine-sheath system. The model jet contains a turbulent spine of half-width 1.2
degrees and maximum Lorentz factor of 16.5, a turbulent sheath with Lorentz
factor of 5, and a boundary region of sheared field between the spine and
sheath. Transverse shocks propagating along the fast, turbulent spine can
explain the superluminal knots. The observed flux density and polarization
variations are then compatible with changes in the direction of the inner jet
caused by a temporary change in the position of the core if the spine contains
wiggles owing to an instability. In addition, we can explain a stable offset of
optical and near-IR percentage polarization by a steepening of spectral index
with frequency, as supported by the data.Comment: 34 pages, 12 figures; To be published in Astrophysical Journal,
accepted 03/200
The fate of the homoctenids (Tentaculitoidea) during the Frasnian-Famennian mass extinction (Late Devonian)
The homoctenids (Tentaculitoidea) are small, conical-shelled marine animals which are amongst the most abundant and widespread of all Late Devonian fossils. They were a principal casualty of the Frasnian-Famennian (F-F, Late Devonian) mass extinction, and thus provide an insight into the extinction dynamics. Despite their abundance during the Late Devonian, they have been largely neglected by extinction studies. A number of Frasnian-Famennian boundary sections have been studied, in Poland, Germany, France, and the United States. These sections have yielded homoctenids, which allow precise recognition of the timing of the mass extinction. It is clear that the homoctenids almost disappear from the fossil record during the latest Frasnian âUpper Kellwasser Eventâ. The coincident extinction of this pelagic group, and the widespread development of intense marine anoxia within the water column, provides a causal link between anoxia and the F-F extinction. Most notable is the sudden demise of a group, which had been present in rock-forming densities, during this anoxic event. One new species, belonging to Homoctenus is described, but is not formally named here
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