Modelling spatial and temporal variations of annual suspended sediment yields from small agricultural catchments.

Estimates of sediment yield are important for ecological and geomorphological assessment of fluvial systems and for assessment of soil erosion within a catchment. Many regulatory frameworks, such as the Convention for the Protection of the Marine Environment of the North-East Atlantic, derived from the Oslo and Paris Commissions (OSPAR) require reporting of annual sediment fluxes. While they may be measured in large rivers, sediment flux is rarely measured in smaller rivers. Measurements of sediment transport at a national scale can be also challenging and therefore, sediment yield models are often utilised by water resource managers for the predictions of sediment yields in the ungauged catchments. Regression based models, calibrated to field measurements, can offer an advantage over complex and computational models due to their simplicity, easy access to input data and due to the additional insights into factors controlling sediment export in the study sites. While traditionally calibrated to long-term average values of sediment yields such predictions cannot represent temporal variations. This study addresses this issue in a novel way by taking account of the variation from year to year in hydrological variables in the developed models (using annual mean runoff, annual mean flow, flows exceeded in five percentage of the time (Q5) and seasonal rainfall estimated separately for each year of observations). Other parameters included in the models represent spatial differences influenced by factors such as soil properties (% poorly drained soils and % peaty soils), land-use (% pasture or % arable lands), channel slope (S1085) and drainage network properties (drainage density). Catchment descriptors together with year-specific hydrological variables can explain both spatial differences and inter-annual variability of suspended sediment yields. The methodology is demonstrated by deriving equations from Irish data-sets (compiled in this study) with the best model efficiency of 0.84 and best model fit of adjusted R2 of 0.82. Presented approach shows the potential for regression based models to model contemporary suspended sediment yields in small river systems.

Antimicrobial activity of gallium against virulent Rhodococcus equiin vitro and in vivo.

Rhodococcus equi, a facultative intracellular bacterium, causes severe pneumonia in foals. Evidence suggests that most foals become infected very early in life, when they have immature or ineffective innate immune responses. This study evaluated the antimicrobial activity of gallium against R. equi, as a potential chemoprophylactic and therapeutic agent. Rhodococcus equi was grown in media with various concentrations of gallium nitrate (GN), with and without excess iron. GN significantly inhibited growth and killed R. equi, and these effects were abolished with excess iron. Antimicrobial effects of Ga appear to be related to its interference with iron metabolism. Mice were treated orally with gallium maltolate (GaM), 10 or 50 mg/kg BW, or distilled H2O prior to and after experimental infection with R. equi. Six days post-infection, organs were harvested and R. equi concentrations assessed, and serum gallium concentrations determined. GaM was absorbed in a dose-dependent manner, and R. equi tissue burdens were greater in control mice than in all GaM-treated mice. GaM may aid in the control of disease by preventing development of overwhelming R. equi tissue burdens prior to the establishment of requisite innate and adaptive immune responses.

Monoblock and modular total shoulder arthroplasty for osteoarthritis.

There are theoretical and practical advantages to modular rather than monoblock designs of prostheses for shoulder arthroplasty, but there are no reported studies which specifically compare the clinical and radiological results of their use. We have compared the results of unconstrained total shoulder arthroplasty for osteoarthritis using both types of implant. The monoblock design was used between 1992 and 1995 and the modular design after 1995. Both had cemented all-polyethylene glenoids, the monoblock with matched and the modular with mismatched radii of curvature. There were 34 consecutive shoulders in each group with a mean follow-up of 6.1 years in the first and 5.2 years in the second.There were no significant differences in improvement of pain scores, active elevation, external rotation, internal rotation, patient satisfaction, or the Neer ratings between the two groups. Two of 28 glenoid components in the first group and six of 30 in the second met the criteria for being radiologically at risk for loosening (p = 0.25). There were no significant differences in clinical outcome or radiological changes between the first- and second-generation designs of implant for shoulder arthroplasty.

Posner-Schlossman syndrome: a case report.

BACKGROUND: Glaucomatocyclitic Crisis (AKA Posner-Schlossman syndrome) is a syndrome that affects patients between the ages of 20 and 50 years. It is characterized by a mild recurrent anterior uveitis associated with an out-of-proportion intraocular pressure spike in the same eye. The cause is unclear, but many theories exist. Some researchers have tried to connect it with primary open-angle glaucoma. CASE REPORT: A review of the record of a 41-year-old Hispanic woman with Posner-Schlossman syndrome is discussed. She sought treatment on multiple occasions with symptoms of mild pain, photophobia, and a blurry left eye. Examination revealed mild anterior chamber reaction and an intraocular pressure (IOP) spike in the same eye. She was treated with topical anti-inflammatory and pressure-lowering agents. Each individual flare-up was treated successfully, but the patient began to show equivocal signs of primary open-angle glaucoma (PDAG). She is currently treated prophylactically for POAG with a beta-blocker. No etiologic factor was identified in this patient. The differential diagnosis is straight-forward and the treatment is general uveitic therapy--minus cycloplegics--combined with an IOP-lowering drop. CONCLUSION: This is an interesting and relatively rare uveitic condition. The list of differential diagnoses is long, as is the theorized etiologies; however, clinically the condition is relatively quickly identifiable by the presence (and absence) of signs and symptoms.

Uncertainty and variation in indirect exposure assessments: an analysis of exposure to tetrachlorodibenzo-p-dioxin from a beef consumption pathway.

Indirect exposures to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and other toxic materials released in incinerator emissions have been identified as a significant concern for human health. As a result, regulatory agencies and researchers have developed specific approaches for evaluating exposures from indirect pathways. This paper presents a quantitative assessment of the effect of uncertainty and variation in exposure parameters on the resulting estimates of TCDD dose rates received by individuals indirectly exposed to incinerator emissions through the consumption of home-grown beef. The assessment uses a nested Monte Carlo model that separately characterizes uncertainty and variation in dose rate estimates. Uncertainty resulting from limited data on the fate and transport of TCDD are evaluated, and variations in estimated dose rates in the exposed population that result from location-specific parameters and individuals' behaviors are characterized. The analysis indicates that lifetime average daily dose rates for individuals living within 10 km of a hypothetical incinerator range over three orders of magnitude. In contrast, the uncertainty in the dose rate distribution appears to vary by less than one order of magnitude, based on the sources of uncertainty included in this analysis. Current guidance for predicting exposures from indirect exposure pathways was found to overestimate the intakes for typical and high-end individuals.

Stability of a potential blood substitute, HbXL99 alpha, under high pressure.

One important criteria for a plasma circulating hemoglobin blood substitute is resistance to subunit dissociation. For this reason, cross-linked hemoglobins (with low oxygen affinities) are being specifically designed to serve as potential blood substitutes. An example is HbXL99 alpha, cross-linked between the alpha-subunits [PNAS (1987) 84:7280]. In the study presented here, the effects of up to 2 kilobars of pressure on the intrinsic fluorescence of HbXL99 alpha, HbA, and myoglobin were compared. Hemoglobin solutions were studied between 0.01-0.1g% in potassium phosphate or Hepes buffers, pH 7.4. Results show HbA exhibits a decrease in fluorescence intensity as a function of pressure. In contrast, HbXL99 alpha as well myoglobin (a monomer) show essentially no significant intrinsic fluorescence changes as a function of pressure. These results suggest that HbXL99 alpha is stable as a tetramer up to approximately 2 kilobars of pressure. In addition, high pressure intrinsic fluorescence studies provide a suitable technique for determining the subunit stability of hemoglobins.

Radioactive cesium from the Chernobyl accident in the Greenland Ice Sheet.

Measurements of cesium-134 and cesium-137 in Greenland snow together with models of long-range transport have been used to assess radionuclide deposition in the Arctic after the Chernobyl accident. The results suggest that a well-defined layer of radioactive cesium is now present in polar glaciers, providing a new reference for estimating snow accumulation rates and dating ice core samples.