LANDSAT menhaden and thread herring resources investigation, Gulf of Mexico

The author has identified the following significant results. The most significant achievements thus far include the successful charting of high probability fishing areas from LANDSAT MSS data and the successful simulation of an operational satellite system to provide tactical information for the commercial harvest of menhaden

LANDSAT menhaden and thread herring resources investigation

The author has identified the following significant results. The relationship between the distribution of menhaden and selected oceanographic parameters (water color, turbidity, and possibly chlorophyll concentrations) was established. Similar relationships for thread herring were not established nor were relationships relating to the abundance of either species. Use of aircraft and LANDSAT remote sensing instruments to measure or infer a set of basic oceanographic parameters was evaluated. Parameters which could be accurately inferred included surface water temperature, salinity, and color. Water turbidity (Secchi disk) was evaluated as marginally inferrable from the LANDSAT MSS data and chlorophyll-a concentrations as less than marginal. These evaluations considered the parameters only as experienced in the two test areas using available sensors and statistical techniques

Bar-Halo Friction in Galaxies II: Metastability

It is well-established that strong bars rotating in dense halos generally slow down as they lose angular momentum to the halo through dynamical friction. Angular momentum exchanges between the bar and halo particles take place at resonances. While some particles gain and others lose, friction arises when there is an excess of gainers over losers. This imbalance results from the generally decreasing numbers of particles with increasing angular momentum, and friction can therefore be avoided if there is no gradient in the density of particles across the major resonances. Here we show that anomalously weak friction can occur for this reason if the pattern speed of the bar fluctuates upwards. After such an event, the density of resonant halo particles has a local inflexion created by the earlier exchanges, and bar slowdown can be delayed for a long period; we describe this as a metastable state. We show that this behavior in purely collisionless N-body simulations is far more likely to occur in methods with adaptive resolution. We also show that the phenomenon could arise in nature, since bar-driven gas inflow could easily raise the bar pattern speed enough to reach the metastable state. Finally, we demonstrate that mild external, or internal, perturbations quickly restore the usual frictional drag, and it is unlikely therefore that a strong bar in a galaxy having a dense halo could rotate for a long period without friction.Comment: 13 pages, 11 figures, to appear in Ap

Perception gaps between patients with ulcerative colitis and healthcare professionals: An online survey

Background: The purpose of this study was to examine the differing perspectives and perceptual gaps relating to ulcerative colitis (UC) symptoms and their management between patients and healthcare professionals (HCPs). Methods: Structured, cross-sectional, Web-based questionnaires designed to assess a variety of disease indices were completed by adult patients with UC and HCPs involved in the care of patients with UC from Canada, France, Germany, Ireland, Spain, and the United Kingdom. Results: Surveys were completed by 775 patients, 475 physicians, and 50 nurses. Patient self-reported classification of disease severity revealed generally greater severity (mild, 32%; moderate, 53%) compared with physician and nurse estimates of UC severity among their caseloads (mild, 52% and 49%; moderate, 34% and 37%, respectively). Patients reported that an average of 5.5 (standard deviation, 11.0) flares (self-defined) occurred over the past year, compared with 3.4 and 3.8 flares per year estimated by physicians and nurses. Perceived flare triggers differed between patients (stress ranked first) and HCPs (natural disease course ranked first). Fifty-five percent of patients stated that UC symptoms over the past year had affected their quality of life, while physicians and nurses estimated that 35% to 37% of patients would have a reduced quality of life over the same period. Patients ranked urgency and pain as the most bothersome symptoms, while physicians and nurses ranked urgency and stool frequency highest. About half of patients (47%) defined remission as experiencing no symptoms; by comparison, 62% to 63% of HCPs defined remission as requiring the complete absence of symptoms. HCPs (doctors/nurses in general practice and/or hospital) were regarded by patients as their main source of UC information by 72%; however, 59% reported not arranging regular visits to see their HCPs. Conclusions: This large survey identified important differences between patients' and HCPs' perceptions of the impact of UC symptoms on patients' lives. Notably, HCPs may underestimate the effect of specific UC symptoms on patients and may fail to recognize issues that are important to patients. © 2015, In House Publications. All rights reserved

Anomalous lifetime distributions and topological traps in ordering dynamics

We address the role of community structure of an interaction network in ordering dynamics, as well as associated forms of metastability. We consider the voter and AB model dynamics in a network model which mimics social interactions. The AB model includes an intermediate state between the two excluding options of the voter model. For the voter model we find dynamical metastable disordered states with a characteristic mean lifetime. However, for the AB dynamics we find a power law distribution of the lifetime of metastable states, so that the mean lifetime is not representative of the dynamics. These trapped metastable states, which can order at all time scales, originate in the mesoscopic network structure.Comment: 7 pages; 6 figure

The Evolution of Cuspy Triaxial Galaxies Harboring Central Black Holes

We use numerical simulations to study the evolution of triaxial elliptical galaxies with central black holes. In contrast to earlier numerical studies which used galaxy models with central density ``cores,'' our galaxies have steep central cusps, like those observed in real ellipticals. As a black hole grows in these cuspy triaxial galaxies, the inner regions become rounder owing to chaos induced in the orbit families which populate the model. At larger radii, however, the models maintain their triaxiality, and orbital analyses show that centrophilic orbits there resist stochasticity over many dynamical times. While black hole induced evolution is strong in the inner regions of these galaxies, and reaches out beyond the nominal ``sphere of influence'' of a black hole, our simulations do not show evidence for a rapid {\it global} transformation of the host. The triaxiality of observed elliptical galaxies is therefore not inconsistent with the presence of supermassive black holes at their centers.Comment: 15 pages, 7 figures (1 color). Accepted for publication in Ap

The 2011 Mw 7.1 Van (Eastern Turkey) earthquake

[1] We use interferometric synthetic aperture radar (InSAR), body wave seismology, satellite imagery, and field observations to constrain the fault parameters of the Mw 7.1 2011 Van (Eastern Turkey) reverse-slip earthquake, in the Turkish-Iranian plateau. Distributed slip models from elastic dislocation modeling of the InSAR surface displacements from ENVISAT and COSMO-SkyMed interferograms indicate up to 9 m of reverse and oblique slip on a pair of en echelon NW 40 °–54 ° dipping fault planes which have surface extensions projecting to just 10 km north of the city of Van. The slip remained buried and is relatively deep, with a centroid depth of 14 km, and the rupture reaching only within 8–9 km of the surface, consistent with the lack of significant ground rupture. The up-dip extension of this modeled WSW striking fault plane coincides with field observations of weak ground deformation seen on the western of the two fault segments and has a dip consistent with that seen at the surface in fault gouge exposed in Quaternary sediments. No significant coseismic slip is found in the upper 8 km of the crust above the main slip patches, except for a small region on the eastern segment potentially resulting from the Mw 5.9 aftershock on the same day. We perform extensive resolution tests on the data to confirm the robustness of the observed slip deficit in the shallow crust. We resolve a steep gradient in displacement at the point where the planes of the two fault segments ends are inferred to abut at depth, possibly exerting some structural control on rupture extent