432 research outputs found

    The Fate of Nitrogen and Faecal Coliform in the Lubigi Wetland in Uganda

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    The capacity of the Lubigi wetland to reduce nitrogen and faecal coliform pollution entering Lake Kyoga in Uganda was investigated. Three transects with 5 sampling points in each, were established in the wetland. Wetland plants samples were collected from the specific locations along the transects, and laboratory tests and analyses were carried out for plants biomass and nitrogen contents determination. Samples of wetland sediments were also collected, and laboratory tests and analyses were done for determination of nitrogen content in the sediments. Wetland water samples were taken from the main wetland inlet and the main outlet from the wetland main study area. At the same time, wetland water pH, dissolved oxygen and temperatures were measured in-situ. Laboratory tests and analyses for ammonia-nitrogen, nitrate-nitrogen, total Kjeldahl nitrogen, total nitrogen and faecal coliforms were carried out on the wetland water samples. The results indicate that the Lubigi wetland received about 16 to 173 mg/l of total nitrogen, largely in form of organic- nitrogen (64.7%) and ammonia-nitrogen (35.2%). Nitrate-nitrogen and Nitrite-nitrite accounted for only 0.1% of the total nitrogen in the inlet. The wetland removed about 24.9% of this nitrogen, which is equivalent to removal of about 1,672 tons of nitrogen annually. About 67.5 gN/m2 and 0.30 gN/kg of dry sediments were sequestered in the wetland plants biomass and the benthic layer respectively. The Lubigi wetland main study area also receives faecal coliform concentrations with the wetland inlet mean value of 653,509 CFU/100ml and its outlet mean value is 218,676 CFU/100ml. These values give a faecal coliform (FC) overall removal efficiency of approximately 66.5%. It was thus concluded that the Lubigi wetland has considerable capacity to buffer and protect Lake Kyoga, by reducing nitrogen and faecal coliform pollution entering the lake

    Is the “Dominant Firm” Dominant? An Empirical Analysis of AT&T’S Market Power

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    In this article, we estimate the degree of market power held by AT&T in the interstate long-distance market in the postdivestiture period. Our approach makes use of the dominant firm/competitive fringe model to impose the structure needed both to obtain estimates of the relevant structural parameters and to translate these parameters into an estimate of AT&T\u27s residual demand elasticity and associated Lerner index. Because of the continued presence of regulation and other considerations, however, a direct estimation of the residual demand elasticity is not feasible. Consequently, we take a more indirect approach that combines estimation of the elasticity of fringe firm supply, market demand estimation, and extant market share data to generate estimates of the desired elasticity. The resulting estimates strongly support the conclusion that AT&T lacks significant market power in the postdivestiture long-distance market

    Understanding the Essex Junto: Fear, Dissent, and Propaganda in the Early Republic

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    Historians have never formed a consensus over the Essex Junto. In fact, though often associated with New England Federalists, propagandists evoked the Junto long after the Federalist Party’s demise in 1824. This article chronicles uses of the term Essex Junto and its significance as it evolved from the early republic through the 1840s

    Binary-induced collapse of a compact, collisionless cluster

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    We improve and extend Shapiro's model of a relativistic, compact object which is stable in isolation but is driven dynamically unstable by the tidal field of a binary companion. Our compact object consists of a dense swarm of test particles moving in randomly-oriented, initially circular, relativistic orbits about a nonrotating black hole. The binary companion is a distant, slowly inspiraling point mass. The tidal field of the companion is treated as a small perturbation on the background Schwarzschild geometry near the hole; the resulting metric is determined by solving the perturbation equations of Regge and Wheeler and Zerilli in the quasi-static limit. The perturbed spacetime supports Bekenstein's conjecture that the horizon area of a near-equilibrium black hole is an adiabatic invariant. We follow the evolution of the system and confirm that gravitational collapse can be induced in a compact collisionless cluster by the tidal field of a binary companion.Comment: 9 Latex pages, 14 postscript figure

    Thrombolytic removal of intraventricular haemorrhage in treatment of severe stroke: results of the randomised, multicentre, multiregion, placebo-controlled CLEAR III trial

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    Background: Intraventricular haemorrhage is a subtype of intracerebral haemorrhage, with 50% mortality and serious disability for survivors. We aimed to test whether attempting to remove intraventricular haemorrhage with alteplase versus saline irrigation improved functional outcome. Methods: In this randomised, double-blinded, placebo-controlled, multiregional trial (CLEAR III), participants with a routinely placed extraventricular drain, in the intensive care unit with stable, non-traumatic intracerebral haemorrhage volume less than 30 mL, intraventricular haemorrhage obstructing the 3rd or 4th ventricles, and no underlying pathology were adaptively randomly assigned (1:1), via a web-based system to receive up to 12 doses, 8 h apart of 1 mg of alteplase or 0·9% saline via the extraventricular drain. The treating physician, clinical research staff, and participants were masked to treatment assignment. CT scans were obtained every 24 h throughout dosing. The primary efficacy outcome was good functional outcome, defined as a modified Rankin Scale score (mRS) of 3 or less at 180 days per central adjudication by blinded evaluators. This study is registered with ClinicalTrials.gov, NCT00784134. Findings: Between Sept 18, 2009, and Jan 13, 2015, 500 patients were randomised: 249 to the alteplase group and 251 to the saline group. 180-day follow-up data were available for analysis from 246 of 249 participants in the alteplase group and 245 of 251 participants in the placebo group. The primary efficacy outcome was similar in each group (good outcome in alteplase group 48% vs saline 45%; risk ratio [RR] 1·06 [95% CI 0·88–1·28; p=0·554]). A difference of 3·5% (RR 1·08 [95% CI 0·90–1·29], p=0·420) was found after adjustment for intraventricular haemorrhage size and thalamic intracerebral haemorrhage. At 180 days, the treatment group had lower case fatality (46 [18%] vs saline 73 [29%], hazard ratio 0·60 [95% CI 0·41–0·86], p=0·006), but a greater proportion with mRS 5 (42 [17%] vs 21 [9%]; RR 1·99 [95% CI 1·22–3·26], p=0·007). Ventriculitis (17 [7%] alteplase vs 31 [12%] saline; RR 0·55 [95% CI 0·31–0·97], p=0·048) and serious adverse events (114 [46%] alteplase vs 151 [60%] saline; RR 0·76 [95% CI 0·64–0·90], p=0·002) were less frequent with alteplase treatment. Symptomatic bleeding (six [2%] in the alteplase group vs five [2%] in the saline group; RR 1·21 [95% CI 0·37–3·91], p=0·771) was similar. Interpretation: In patients with intraventricular haemorrhage and a routine extraventricular drain, irrigation with alteplase did not substantially improve functional outcomes at the mRS 3 cutoff compared with irrigation with saline. Protocol-based use of alteplase with extraventricular drain seems safe. Future investigation is needed to determine whether a greater frequency of complete intraventricular haemorrhage removal via alteplase produces gains in functional status
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