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Rhegmatogenous retinal detachment masquerading as exudative panuveitis with intense anterior chamber inflammatory reaction.
Purpose:This is a retrospective case report illustrating the diagnostic and therapeutic challenges associated with a chronic rhegmatogenous retinal detachment masquerading as a severe panuveitis with intense anterior chamber inflammation. We have included clinical features, anterior segment and fundus photography, B-scan ultrasonography, fluorescein angiography, and intraoperative findings. Observations:A 26-year-old male presented with features of unilateral panuveitis: hypotony, anterior segment inflammation (posterior synechiae and anterior chamber cell with fibrin clumping), diffuse choroidal thickening, and retinal detachment. Laboratory investigations for infectious or rheumatologic processes were negative, and empiric systemic corticosteroid therapy was unsuccessful. This prompted suspicion for an alternate primary etiology, and pars plana vitrectomy revealed small retinal breaks as the underlying cause of the retinal detachment and inflammation. Conclusions:Rhegmatogenous retinal detachments are a known cause of intraocular inflammation. Nevertheless, it remains a challenge to recognize retinal breaks in this setting, particularly with robust anterior segment inflammation and posterior findings resembling severe exudative uveitis. Being aware of this unique presentation may prevent delays in diagnosis and have important prognostic implications
Localization for Random Unitary Operators
We consider unitary analogs of dimensional Anderson models on
defined by the product where is a deterministic
unitary and is a diagonal matrix of i.i.d. random phases. The
operator is an absolutely continuous band matrix which depends on a
parameter controlling the size of its off-diagonal elements. We prove that the
spectrum of is pure point almost surely for all values of the
parameter of . We provide similar results for unitary operators defined on
together with an application to orthogonal polynomials on the unit
circle. We get almost sure localization for polynomials characterized by
Verblunski coefficients of constant modulus and correlated random phases
Geophysical and geochemical signatures of Gulf of Mexico seafloor brines
International audienceGeophysical, temperature, and discrete depth-stratified geochemical data illustrate differences between an actively venting mud volcano and a relatively quiescent brine pool in the Gulf of Mexico along the continental slope. Geophysical data, including laser-line scan mosaics and sub-bottom profiles, document the dynamic nature of both environments. Temperature profiles, obtained by lowering a CTD into the brine fluid, show that the venting brine was at least 10°C warmer than the bottom water. At the brine pool, thermal stratification was observed and only small differences in stratification were documented between three sampling times (1991, 1997 and 1998). In contrast, at the mud volcano, substantial temperature variability was observed, with the core brine temperature being slightly higher than bottom water (by 2°C) in 1997 but substantially higher than bottom water (by 19°C) in 1998. Detailed geochemical samples were obtained in 2002 using a device called the "brine trapper" and concentrations of dissolved gases, major ions and nutrients were determined. Both brines contained about four times as much salt as seawater and steep concentration gradients of dissolved ions and nutrients versus brine depth were apparent. Differences in the concentrations of calcium, magnesium and potassium between the two brine fluids suggest that the fluids are derived from different sources, have different dilution/mixing histories, or that brine-sediment reactions are more important at the mud volcano. Substantial concentrations of methane, ammonium, and silicate were observed in both brines, suggesting that fluids expelled from deep ocean brines are important sources of these constituents to the surrounding environment
Contemporaneous nitrogen fixation and denitrification in intertidal microbial mats: rapid response to runoff events
We examined the contemporaneous responses of N2 fixation and denitrification to inorganic nitrogen-enriched runoff in 2 intertidal microbial mats in Tomales Bay (California, USA). Prior to runoff, N2 fixation rates averaged 3 mmol N m-2 d-1. Denitrification rates were lower, corresponding to 0 to 25 % of N2 fixation rates. After the initiation of runoff, N2 fixation rates decreased, approaching zero at both sites. In contrast, denitrification rates increased by an order of magnitude. We developed a simple model to examine the magnitude of N removal from creek water by mat denitrification before, during and after runoff. Model results show that during peak runoff, N removal was limited by the residence time of creek water in the intertidal region. As runoff volumes decreased and residence times increased, N removal became limited by the supply of organic matter. Our results illustrated the rapid metabolic adaptation of microbial mats to altered N fluxes. Changes occurring in the mat N cycling after the initiation of runoff led to 2 fundamental ecological changes: (1) mats became sinks for rather than sources of fixed N and (2) denitrification became limited by the availability of organic carbon rather than nitrate
Localization Properties of the Chalker-Coddington Model
The Chalker Coddington quantum network percolation model is numerically
pertinent to the understanding of the delocalization transition of the quantum
Hall effect. We study the model restricted to a cylinder of perimeter 2M. We
prove firstly that the Lyapunov exponents are simple and in particular that the
localization length is finite; secondly that this implies spectral
localization. Thirdly we prove a Thouless formula and compute the mean Lyapunov
exponent which is independent of M.Comment: 29 pages, 1 figure. New section added in which simplicity of the
Lyapunov spectrum and finiteness of the localization length are proven. To
appear in Annales Henri Poincar
Importance of Suspended Particulates in Riverine Delivery of Bioavailable Nitrogen to Coastal Zones
Total nitrogen (TN) loadings in riverine sediments and their coastal depocenters were compared for Il river systems worldwide to assess the potential impact of riverine particulates on coastal nitrogen budgets. Strong relationships between sediment specific surface area and TN allow these impacts to be estimated without the intense sampling normally required to achieve such budgets. About half of the systems showed higher nitrogen loadings in the riverine sediments than those from the coastal depocenter. In spite of uncertainties, these comparisons indicate that large, turbid rivers, such as the Amazon, Huanghe, and the Mississippi, deliver sediments that in turn release significant or major fractions of the total riverine nitrogen delivery. Riverine particulates must therefore be considered an essential factor in watershed nutrient loading to coastal ecosystems and may affect delivered nutrient ratios as well as total nutrient loading. The relative importance of particulate versus dissolved delivery has decreased over recent decades in the Mississippi as a result of damming and fertilizer use in the watershed
Spitzer observations of Bow Shocks and Outflows in RCW 38
We report Spitzer observations of five newly identified bow shocks in the
massive star-forming region RCW 38. Four are visible at IRAC wavelengths, the
fifth is visible only at 24 microns. Chandra X-ray emission indicates that
winds from the central O5.5 binary, IRS~2, have caused an outflow to the NE and
SW of the central subcluster. The southern lobe of hot ionised gas is detected
in X-rays; shocked gas and heated dust from the shock-front are detected with
Spitzer at 4.5 and 24 microns. The northern outflow may have initiated the
present generation of star formation, based on the filamentary distribution of
the protostars in the central subcluster. Further, the bow-shock driving star,
YSO 129, is photo-evaporating a pillar of gas and dust. No point sources are
identified within this pillar at near- to mid-IR wavelengths.
We also report on IRAC 3.6 & 5.8 micron observations of the cluster
DBS2003-124, NE of RCW 38, where 33 candidate YSOs are identified. One star
associated with the cluster drives a parsec-scale jet. Two candidate HH objects
associated with the jet are visible at IRAC and MIPS wavelengths. The jet
extends over a distance of ~3 pc. Assuming a velocity of 100 km/s for the jet
material gives an age of about 30,000 years, indicating that the star (and
cluster) are likely to be very young, with a similar or possibly younger age
than RCW 38, and that star formation is ongoing in the extended RCW 38 region.Comment: 27 pages, 6 figures, accepted to Ap
Barite encrustation of benthic sulfur-oxidizing bacteria at a marine cold seep
Crusts and chimneys composed of authigenic barite are found at methane seeps and hydrothermal vents that expel fluids rich in barium. Microbial processes have not previously been associated with barite precipitation in marine cold seep settings. Here, we report on the precipitation of barite on filaments of sulfide-oxidizing bacteria at a brine seep in the Gulf of Mexico. Barite-mineralized bacterial filaments in the interiors of authigenic barite crusts resemble filamentous sulfide-oxidizing bacteria of the genus Beggiatoa. Clone library and iTag amplicon sequencing of the 16S rRNA gene show that the barite crusts that host these filaments also preserve DNA of Candidatus Maribeggiatoa, as well as sulfate-reducing bacteria. Isotopic analyses show that the sulfur and oxygen isotope compositions of barite have lower δ34S and δ18O values than many other marine barite crusts, which is consistent with barite precipitation in an environment in which sulfide oxidation was occurring. Laboratory experiments employing isolates of sulfide-oxidizing bacteria from Gulf of Mexico seep sediments showed that under low sulfate conditions, such as those encountered in brine fluids, sulfate generated by sulfide-oxidizing bacteria fosters rapid barite precipitation localized on cell biomass, leading to the encrustation of bacteria in a manner reminiscent of our observations of barite-mineralized Beggiatoa in the Gulf of Mexico. The precipitation of barite directly on filaments of sulfide-oxidizing bacteria, and not on other benthic substrates, suggests that sulfide oxidation plays a role in barite formation at certain marine brine seeps where sulfide is oxidized to sulfate in contact with barium-rich fluids, either prior to, or during, the mixing of those fluids with sulfate-containing seawater in the vicinity of the sediment/water interface. As with many other geochemical interfaces that foster mineral precipitation, both biological and abiological processes likely contribute to the precipitation of barite at marine brine seeps such as the one studied here
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