Bacterially mediated removal of phosphorus and cycling of nitrate and sulfate in the waste stream of a "zero-discharge" recirculating mariculture system

Simultaneous removal of nitrogen and phosphorus by microbial biofilters has been used in a variety of water treatment systems including treatment systems in aquaculture. In this study, phosphorus, nitrate and sulfate cycling in the anaerobic loop of a zero-discharge, recirculating mariculture system was investigated using detailed geochemical measurements in the sludge layer of the digestion basin. High concentrations of nitrate and sulfate, circulating in the overlying water (~15 mM), were removed by microbial respiration in the sludge resulting in a sulfide accumulation of up to 3 mM. Modelling of the observed S and O isotopic ratios in the surface sludge suggested that, with time, major respiration processes shifted from heterotrophic nitrate and sulfate reduction to autotrophic nitrate reduction. The much higher inorganic P content of the sludge relative to the fish feces is attributed to conversion of organic P to authigenic apatite. This conclusion is supported by: (a) X-ray diffraction analyses, which pointed to an accumulation of a calcium phosphate mineral phase that was different from P phases found in the feces, (b) the calculation that the pore waters of the sludge were highly oversaturated with respect to hydroxyapatite (saturation index = 4.87) and (c) there was a decrease in phosphate (and in the Ca/Na molar ratio) in the pore waters simultaneous with an increase in ammonia showing there had to be an additional P removal process at the same time as the heterotrophic breakdown of organic matter

Extreme events and predictability of catastrophic failure in composite materials and in the Earth

Despite all attempts to isolate and predict extreme earthquakes, these nearly always occur without obvious warning in real time: fully deterministic earthquake prediction is very much a ‘black swan’. On the other hand engineering-scale samples of rocks and other composite materials often show clear precursors to dynamic failure under controlled conditions in the laboratory, and successful evacuations have occurred before several volcanic eruptions. This may be because extreme earthquakes are not statistically special, being an emergent property of the process of dynamic rupture. Nevertheless, probabilistic forecasting of event rate above a given size, based on the tendency of earthquakes to cluster in space and time, can have significant skill compared to say random failure, even in real-time mode. We address several questions in this debate, using examples from the Earth (earthquakes, volcanoes) and the laboratory, including the following. How can we identify ‘characteristic’ events, i.e. beyond the power law, in model selection (do dragon-kings exist)? How do we discriminate quantitatively between stationary and non-stationary hazard models (is a dragon likely to come soon)? Does the system size (the size of the dragon’s domain) matter? Are there localising signals of imminent catastrophic failure we may not be able to access (is the dragon effectively invisible on approach)? We focus on the effect of sampling effects and statistical uncertainty in the identification of extreme events and their predictability, and highlight the strong influence of scaling in space and time as an outstanding issue to be addressed by quantitative studies, experimentation and models

Mouse Chromosome 3

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46995/1/335_2004_Article_BF00648421.pd

Synthesis And X-ray Analysis Of The Tetranuclear Iridium Compounds Hir4(co)9(μ4-η3-ph 2pccph)(μ-pph2) And Ir4(co)7(μ-co)(μ3-η 2-hccph)(μ-pph2)2 And Multinuclear Nmr Studies Of The Latter Compound

Reaction of HIr4(CO)10(μ-PPh2) (1) with Ph2PC≡CPh yields the CO-substituted compounds HIr4(CO)10-n(Ph2PC≡CPh) n(μ-PPh2), n = 1 (2) and 2 (3). The monosubstituted species (2) undergoes facile P-C bond cleavage, followed by acetylide insertion into the Ir-H bond to give Ir4(CO)7(μ3-η2-HC 2Ph)(μ-CO)(μ-PPh2)2 (4) in high yields, and under more forcing conditions, HIr4(CO)9(μ4-η3-Ph 2PCCPh)(μ-PPh2) (6) is also obtained. Compound 4 is also formed upon thermolysis of Ir4(CO)10(PPh2H)(Ph2PC≡CPh) (7), which is obtained from carbonyl substitution in Ir4(CO)11(PPh2H) (8) with Ph2PC≡CPh. Crystal data for 4: space group P21/n, a = 8.94(2) Å, b = 39.05(2) Å, c = 11.954(6) Å, β = 104.57(8)°, V = 4037.1 Å3, Z = 4, and final R (Rw) value 0.069 (0.073), for 2108 unique reflections [Fc > 4(Fo)]. Compound 4 exhibits a tetrahedral metal framework, with two elongated edges bridged by the μ-PPh2 ligands and a phenylacetylene bound to the cluster in the μ3-η2-∥ fashion. 1H, 13C{1H}, and 31P{1H} NMR spectroscopy studies have established that compound 4 is present in solution in the form of two isomers in a 1:2 ratio, which differ with respect to the orientation of the acetylene ligand and undergo two distinct dynamic processes: at low temperature, ca. 60° rocking of the acetylene with ΔG‡192 = 9.0 kcal mol-1, and estimated ΔG‡169 = 5.4 kcal mol-1, and interconversion of the two isomers at 82°C, with ΔG‡ = 21.8 kcal mol-1 via rotation of the acetylene by 120° steps. Crystal data for 6: space group P21/n, a = 11.840(3) Å, b = 18.745(9) Å, c = 18.695(8) Å, β = 100.63(3)°, V = 4077.9 Å3, Z = 4; final R(Rw) value 0.058 (0.060) for 2609 independent reflections observed [Fc > 4(Fo)]. Compound 6 exhibits a flat butterfly arrangement of metal atoms, with an elongated edge bridged by a PPh2 ligand and all metal atoms interacting with Ph2PCCPh, which acts as a 6-electron ligand. © 1993 American Chemical Society.12829472954ACM Special Interest Group on Hypertext,,Hypermedia and the Web (SIGWEB

Dynamic Coast: Adaptation and Resilience Options at the Bay of Skaill. CRW2017_08

Complementing the national-scale assessments, we have worked with local partners to appreciate local changes at a number of super sites. These reports show how we can use Dynamic Coast research to inform resilience and adaptation plans across a number of locations