Stable carbon and nitrogen isotope composition of organic matter in sediments of the Oman Margin

Stable isotopic compositions of carbon and nitrogen and organic carbon content of sediments ranging from the Pliocene to the Pleistocene-Holocene in age from the Oman Margin (ODP Sites 724 and 725) are reported. In general, the organic carbon content is greater than 2% at Site 724. Prior to the Pleistocene-Holocene at this site, sediments with higher content of organic matter were deposited owing to favorable preservation conditions and/or higher productivity. In the Pleistocene, lower amounts of organic matter have been preserved; this material generally has more enriched nitrogen isotopic compositions. This may indicate intensification of the Oxygen Minimum Zone and denitrification with the onset of the Pleistocene. A correlation of carbon isotope content of these sediments with oxygen isotope stages at Site 724 indicates an enrichment in 13C during glacial events. Based on the stable isotope evidence of both carbon and nitrogen, there does not appear to be major input of terrigenous-derived allochthonous material in this marine environment. The timing and extent of monsoon winds on the productivity of this region are not evident, but require further studies for collaborative interpretation of small-scale features in the isotopic and carbon content of this environment.

Combined effects of coral reef foraminifera Marginopora vertebralis and Heterostegina depressa in a multi-fractorial experiment

Warming and changes in ocean carbonate chemistry alter marine coastal ecosystems at an accelerating pace. The interaction between these stressors has been the subject of recent studies on reef organisms such as corals, bryozoa, molluscs, and crustose coralline algae. Here we investigated the combined effects of elevated sea surface temperatures and pCO2 on two species of photosymbiont-bearing coral reef Foraminifera: Heterostegina depressa (hosting diatoms) and Marginopora vertebralis (hosting dinoflagellates). The effects of single and combined stressors were studied by monitoring survivorship, growth, and physiological parameters, such as respiration, photochemistry (pulse amplitude modulation fluorometry and oxygen production), and chl a content. Specimens were exposed in flow-through aquaria for up to seven weeks to combinations of two pCO2 (~790 and ~490 µatm) and two temperature (28 and 31 °C) regimes. Elevated temperature had negative effects on the physiology of both species. Elevated pCO2 had negative effects on growth and apparent photosynthetic rate in H.depressa but a positive effect on effective quantum yield. With increasing pCO2, chl a content decreased in H. depressa and increased in M. vertebralis. The strongest stress responses were observed when the two stressors acted in combination. An interaction term was statistically significant in half of the measured parameters. Further exploration revealed that 75 % of these cases showed a synergistic (= larger than additive) interaction between the two stressors. These results indicate that negative physiological effects on photosymbiont-bearing coral reef Foraminifera are likely to be stronger under simultaneous acidification and temperature rise than what would be expected from the effect of each of the stressors individually.

Comparative phylogeographic summary statistics for testing simultaneous vicariance

Testing for simultaneous vicariance across comparative phylogeographic data sets is a notoriously difficult problem hindered by mutational variance, the coalescent variance, and variability across pairs of sister taxa in parameters that affect genetic divergence. We simulate vicariance to characterize the behaviour of several commonly used summary statistics across a range of divergence times, and to characterize this behaviour in comparative phylogeographic datasets having multiple taxon-pairs. We found Tajima's D to be relatively uncorrelated with other summary statistics across divergence times, and using simple hypothesis testing of simultaneous vicariance given variable population sizes, we counter-intuitively found that the variance across taxon pairs in Nei and Li's net nucleotide divergence (pi(net)), a common measure of population divergence, is often inferior to using the variance in Tajima's D across taxon pairs as a test statistic to distinguish ancient simultaneous vicariance from variable vicariance histories. The opposite and more intuitive pattern is found for testing more recent simultaneous vicariance, and overall we found that depending on the timing of vicariance, one of these two test statistics can achieve high statistical power for rejecting simultaneous vicariance, given a reasonable number of intron loci (> 5 loci, 400 bp) and a range of conditions. These results suggest that components of these two composite summary statistics should be used in future simulation-based methods which can simultaneously use a pool of summary statistics to test comparative the phylogeographic hypotheses we consider here.

Vehicle routing and crew scheduling for metropolitan mail distribution at Australia Post

This paper presents a new multi-depot combined vehicle and crew scheduling algorithm, and uses it, in conjunction with a heuristic vehicle routing algorithm, to solve the intra-city mail distribution problem faced by Australia Post. First we describe the Australia Post mail distribution problem and outline the heuristic vehicle routing algorithm used to find vehicle routes. We present a new multi-depot combined vehicle and crew scheduling algorithm based on set covering with column generation. The paper concludes with a computational investigation examining the affect of different types of vehicle routing solutions on the vehicle and crew scheduling solution, comparing the different levels of integration possible with the new vehicle and crew scheduling algorithm and comparing the results of sequential versus simultaneous vehicle and crew scheduling, using real life data for Australia Post distribution networks.

Characterisation of the signalment, clinical and survival characteristics of 41 cats with mast cell neoplasia

Mast cell tumours (MCTs) are relatively common tumours of cats, and are the second most common cutaneous tumours in cats in the USA. While the primary splenic form of the disease is far less common, it is usually associated with more severe clinical signs. Signalment, clinical and survival characteristics of mast cell neoplasia were characterised in 41 cats. The most common tumour location was cutaneous/ subcutaneous head and trunk. Stage la was the most common tumour stage at first diagnosis (n = 20), followed by stage 4 (both stage 4a and stage 4b; n = 10). Of 22 cats that underwent excisional biopsy, mast cell neoplasia recurred in four cats during the study period. Three of the 41 cats presented with simultaneous cutaneous and either splenic or lymph node tumours. A comparison between cats with only cutaneous tumours (n = 30) and those with tumours involving the spleen or lymph nodes (n = 11) showed longer survival times for the cutaneous-only group (P = 0.031). Twelve of the 41 cats died of mast cell neoplasia during the study period. When a subgroup of cats with only cutaneous tumours (no lymph node or visceral involvement) were divided according to whether there were multiple (five or more) tumours (n = 6) or a single tumour (n = 19), cats with single tumours survived longer than those with multiple tumours (P = 0.001). Solitary cutaneous feline MCTs without spread to the lymph nodes usually manifest as benign disease with a relatively protracted course. However, multiple cutaneous tumours, recurrent tumours and primary splenic disease should receive a guarded prognosis due to the relatively short median survival times associated with these forms of the disease. (C) 2006 ESFM and AAFR Published by Elsevier Ltd. All rights reserved.

Comparison of near visual acuity and reading metrics in presbyopia correction

PURPOSE: To provide a consistent standard for the evaluation of different types of presbyopic correction. SETTING: Eye Clinic, School of Life and Health Sciences, Aston University, Birmingham, United Kingdom. METHODS: Presbyopic corrections examined were accommodating intraocular lenses (IOLs), simultaneous multifocal and monovision contact lenses, and varifocal spectacles. Binocular near visual acuity measured with different optotypes (uppercase letters, lowercase letters, and words) and reading metrics assessed with the Minnesota Near Reading chart (reading acuity, critical print size [CPS], CPS reading speed) were intercorrelated (Pearson product moment correlations) and assessed for concordance (intraclass correlation coefficients [ICC]) and agreement (Bland-Altman analysis) for indication of clinical usefulness. RESULTS: Nineteen accommodating IOL cases, 40 simultaneous contact lens cases, and 38 varifocal spectacle cases were evaluated. Other than CPS reading speed, all near visual acuity and reading metrics correlated well with each other (r>0.70, P<.001). Near visual acuity measured with uppercase letters was highly concordant (ICC, 0.78) and in close agreement with lowercase letters (+/- 0.17 logMAR). Near word acuity agreed well with reading acuity (+/- 0.16 logMAR), which in turn agreed well with near visual acuity measured with uppercase letters 0.16 logMAR). Concordance (ICC, 0.18 to 0.46) and agreement (+/- 0.24 to 0.30 logMAR) of CPS with the other near metrics was moderate. CONCLUSION: Measurement of near visual ability in presbyopia should be standardized to include assessment of near visual acuity with logMAR uppercase-letter optotypes, smallest logMAR print size that maintains maximum reading speed (CPS), and reading speed. J Cataract Refract Surg 2009; 35:1401-1409 (C) 2009 ASCRS and ESCRS

Bioreaction and separation in batch chromatographic columns

The objective of this work has been to study the behaviour and performance of a batch chromatographic column under simultaneous bioreaction and separation conditions for several carbohydrate feedstocks. Four bioreactions were chosen, namely the hydrolysis of sucrose to glucose and fructose using the enzyme invertase, the hydrolysis of inulin to fructose and glucose using inulinase, the hydrolysis of lactose to glucose and galactose using lactase and the isomerization of glucose to fructose using glucose isomerase. The chromatographic columns employed were jacketed glass columns ranging from 1 m to 2 m long and the internal diameter ranging from 0.97 cm to 1.97 cm. The stationary phase used was a cation exchange resin (PUROLITE PCR-833) in the Ca2+ form for the hydrolysis and the Mg2+ form for the isomerization reactions. The mobile phase used was a diluted enzyme solution which was continuously pumped through the chromatographic bed. The substrate was injected at the top of the bed as a pulse. The effect of the parameters pulse size, the amount of substrate solution introduced into the system corresponding to a percentage of the total empty column volume (% TECV), pulse concentration, eluent flowrate and the enzyme activity of the eluent were investigated. For the system sucrose-invertase complete conversions of substrate were achieved for pulse sizes and pulse concentrations of up to 20% TECV and 60% w/v, respectively. Products with purity above 90% were obtained. The enzyme consumption was 45% of the amount theoretically required to produce the same amount of product as in a conventional batch reactor. A value of 27 kg sucrose/m3 resin/h for the throughput of the system was achieved. The systematic investigation of the factors affecting the performance of the batch chromatographic bioreactor-separator was carried out by employing a factorial experimental procedure. The main factors affecting the performance of the system were the flowrate and enzyme activity. For the system inulin-inulinase total conversions were also obtained for pulses sizes of up to 20 % TECV and a pulse concentration of 10 % w/v. Fructose rich fractions with 100 % purity and representing up to 99.4 % of the total fructose generated were obtained with an enzyme consumption of 32 % of the amount theoretically required to produce the same amount of product in a conventional batch reactor. The hydrolysis of lactose by lactase was studied in the glass columns and also in an SCCR-S unit adapted for batch operation, in co-operation with Dr. Shieh, a fellow researcher in the Chemical Engineering and Applied Chemistry Department at Aston University. By operating at up to 30 % w/v lactose feed concentrations complete conversions were obtained and the purities of the products generated were above 90%. An enzyme consumption of 48 % of the amount theoretically required to produce the same amount of product in a conventional batch reactor was achieved. On working with the system glucose-glucose isomerase, which is a reversible reaction, the separation obtained with the stationary phase conditioned in the magnesium form was very poor although the conversion obtained was compatible with those for conventional batch reactors. By working with a mixed pulse of enzyme and substrate, up to 82.5 % of the fructose generated with a purity of 100 % was obtained. The mathematical modelling and computer simulation of the batch chromatographic bioreaction-separation has been performed on a personal computer. A finite difference method was used to solve the partial differential equations and the simulation results showed good agreement with the experimental results.

Biosynthesis and separation of dextran fructose mixtures in a chromatographic reactor

A literature review of work carried out on batch and continuous chromatographic biochemical reactor-separators has been made. The major part of this work has involved the development of a batch chromatographic reactor-separator for the production of dextran and fructose by the enzymatic action of the enzyme dextransucrase on sucrose. In this reactor, simultaneous reaction and separation occurs thus reducing downstream processing and isolation of products as compared to the existing industrial process. The chromatographic reactor consisted of a glass column packed with a stationary phase consisting of cross linked polysytrene resin in the calcium form. The mobile phase consisted of diluted dextransucrase in deionised water. Initial experiments were carried out on a reactor separtor which had an internal diameter of 0.97cm and length of 1.5m. To study the effect of scale up the reactor diameter was doubled to 1.94cm and length increased to 1.75m. The results have shown that the chromatographic reactor uses more enzyme than a conventional batch reactor for a given conversion of sucrose and that an increase in void volume results in higher conversions of sucrose. A comparison of the molecular weight distribution of dextran produced by the chromatographic reactor was made with that from a conventional batch reactor. The results have shown that the chromatographic reactor produces 30% more dextran of molecular weight greater than 150,000 daltons at 20% w/v sucrose concentration than conventional reactors. This is because some of the fructose molecules are prevented as acting as acceptors in the chromatographic reactor due to their removal from the reaction zone. In the conventional reactor this is not possible and therefore a greater proportion of low molecular weight dextran is produced which does not have much clinical use. A theoretical model was developed to describe the behaviour of the reactor separator and this model was simulated using a computer. The simulation predictions showed good agreement with experimental results at high eluent flowrates and low conversions.

Strategy making process, its content and context in small professional football clubs

This thesis examines the phenomenon of strategy. Making as practised by small professional football clubs. The study was undertaken because football clubs were perceived to have problems with strategy-making and because it was believed that the specific circumstances of football clubs could be outside the range of views covered by conventional views of strategy-making. The characteristics of the club environment are its uncertainty and unpredictability, simultaneous competition and co--operation, strong regulations, and a not-for-profit orientation. Small clubs in particular face a constant struggle for financial viability and survival, due in part to split business and playing objectives. The study was designed to establish the extent and nature of the difficulties clubs experience with a view to preparing the way for creating practical guidance on ways to overcome them. Clearly, in order to survive in the long term, small professional football clubs require very effective strategic decisions. This study has addressed this issue by inquiring into the nature of strategy making for these organisations with the objective to establish the general direction in which the football clubs in question should be moving. As a result, the main research question to guide this investigation was determined as: Why do small professional football clubs have difficulties making strategies. The investigation was based on an analysis the concept of strategy and its elements, the strategic vision and objectives, the process by which strategic action comes about, the strategic action itself, and the context within which this action occurs. Data has been collected, analysed and interpreted in relation to each of these elements. Together with a wide variety of published material, 20 small football clubs have been sampled and personal interviews were conducted with board members of those clubs. The findings indicate that small football clubs do indeed experience considerable difficulties in making strategies, the reasons for which lie both in the characteristics of their competitive environment and their approaches to strategy-making. The competitive environment is characterised by a cartel-like structure with a high degree of regulation, high levels of uncertainty, little control over the core product or the production process, short-term business cycles and a close geographical link between a club with its local market. The management of clubs is characterised by the need to balance conflicting sporting and business objectives. Formal planning techniques are of little use in the small football club context as decision-making processes have a strong political character and the development of novel strategies is hindered by a strong conservative, industry paradigm and a lack of financial and managerial resources. It is concluded that there is no simple advice to be given to clubs, as they must re-examine the relationship between their playing and business objectives to create a unified and workable approach.

Mass transfer and chemical reaction on a distillation plate

A multistage distillation column in which mass transfer and a reversible chemical reaction occurred simultaneously, has been investigated to formulate a technique by which this process can be analysed or predicted. A transesterification reaction between ethyl alcohol and butyl acetate, catalysed by concentrated sulphuric acid, was selected for the investigation and all the components were analysed on a gas liquid chromatograph. The transesterification reaction kinetics have been studied in a batch reactor for catalyst concentrations of 0.1 - 1.0 weight percent and temperatures between 21.4 and 85.0 °C. The reaction was found to be second order and dependent on the catalyst concentration at a given temperature. The vapour liquid equilibrium data for six binary, four ternary and one quaternary systems are measured at atmospheric pressure using a modified Cathala dynamic equilibrium still. The systems with the exception of ethyl alcohol - butyl alcohol mixtures, were found to be non-ideal. Multicomponent vapour liquid equilibrium compositions were predicted by a computer programme which utilised the Van Laar constants obtained from the binary data sets. Good agreement was obtained between the predicted and experimental quaternary equilibrium vapour compositions. Continuous transesterification experiments were carried out in a six stage sieve plate distillation column. The column was 3" in internal diameter and of unit construction in glass. The plates were 8" apart and had a free area of 7.7%. Both the liquid and vapour streams were analysed. The component conversion was dependent on the boilup rate and the reflux ratio. Because of the presence of the reaction, the concentration of one of the lighter components increased below the feed plate. In the same region a highly developed foam was formed due to the presence of the catalyst. The experimental results were analysed by the solution of a series of simultaneous enthalpy and mass equations. Good agreement was obtained between the experimental and calculated results.

Multi-band carrier-less amplitude and phase modulation for bandlimited visible light communications systems

Visible light communications is a technology with enormous potential for a wide range of applications within next generation transmission and broadcasting technologies. VLC offers simultaneous illumination and data communications by intensity modulating the optical power emitted by LEDs operating in the visible range of the electromagnetic spectrum (~370-780 nm). The major challenge in VLC systems to date has been in improving transmission speeds, considering the low bandwidths available with commercial LED devices. Thus, to improve the spectral usage, the research community has increasingly turned to advanced modulation formats such as orthogonal frequency-division multiplexing. In this article we introduce a new modulation scheme into the VLC domain; multiband carrier-less amplitude and phase modulation (m-CAP) and describe in detail its performance within the context of bandlimited systems.

Intra- and interannual variability in seagrass carbon and nitrogen stable isotopes from south Florida, a preliminary study

δ13C and δ15N values were determined for the seagrassThalassia testudinum at four permanent seagrass monitoring stations in southFlorida, USA, through a quarterly sampling program over 3-years (1996–1998). All sites are seagrass beds with water depths of less than 6 m. Two sites are located on the Florida Bay side of the Florida Keys, and the other two sites are on the Atlantic side. The data analyzed over the 3 year study period display unique patterns associated with seasonal changes in primary productivity and potentially changes in the N and C pools. The mean carbon and nitrogenisotope values of T. testudinum from all four stations vary from −7.2 to −10.4‰ and 1.1 to 2.2‰, respectively. However, certain stations displayed anomalously depleted nitrogenisotope values (as low as −1.2‰). These values may indicate that biogeochemical processes like N fixation, ammonification and denitrification cause temporal changes in the isotopic composition of the source DIN. Both δ13C and δ15N values displayed seasonal enrichment-depletion patterns, with maximum enrichment occurring during the summer to early fall. The intra-annual variations of δ13C values from the different stations ranged from about 1 to 3.5‰; whereas variations in δ15N ranged from about 1 to 4.9‰. Certain sites showed a positive relationship between isotope values and productivity. These data indicate δ13C values display a high degree of seasonal variability as related to changes in productivity. δ15N values show clear intra-annual variations, but the observed changes do not necessarily follow a distinct seasonal cycle, indicating that changes in DIN will need further investigation.

Biogeochemistry of Nitrogen Across the Everglades Landscape

Compared to phosphorus (P), nitrogen (N) has received little attention across the Everglades landscape. Despite this lack of attention, N plays important roles in many Everglades systems, including being a significant pollutant in Florida Bay and the Gulf of Mexico, the limiting nutrient in highly P-impacted areas, and an important substrate for microbial metabolism. Storage and transport of N throughout the Everglades is dominated by organic forms, including peat soils and dissolved organic N in the water column. In general, N sources are highest in the northern areas; however, atmospheric deposition and active N2 fixation by the periphyton components are a significant N source throughout most systems. Many of the processes involved in the wetland N cycle remain unmeasured for most of the Everglades systems. In particular, the lack of in situ rates for N2 fixation and denitrification prevent the construction of system-level budgets, especially for the Southern mangrove systems where N export into Florida Bay is critical. There is also the potential for several novel N processes (e.g., Anammox) with an as yet undetermined importance for nitrogen cycling and function of the Everglades ecosystem. Phosphorus loading alters the N cycle by stimulating organic N mineralization with resulting flux of ammonium and DON, and at elevated P concentrations, by increasing rates of N2 fixation and N assimilation. Restoration of hydrology has a potential for significantly impacting N cycling in the Everglades both in terms of affecting N transport, but also by altering aerobic-anaerobic transitions at the soil-water interface or in areas with seasonal drawdowns (e.g., marl prairies). Based on the authors’ understanding of N processes, much more research is necessary to adequately predict potential impacts from hydrologic restoration, as well as the function of Everglades systems as sinks, sources, and transformers of N in the South Florida landscape.

Method development for the analysis of smokeless powders and organic gunshot residue by ultra performance liquid chromatography with tandem mass spectrometry

The goal of this project was to develop a rapid separation and detection method for analyzing organic compounds in smokeless powders and then test its applicability on gunshot residue (GSR) samples. In this project, a total of 20 common smokeless powder additives and their decomposition products were separated by ultra performance liquid chromatography (UPLC) and confirmed by tandem mass spectrometry (MS/MS) using multiple reaction monitoring mode (MRM). Some of the targeted compounds included diphenylamines, centralites, nitrotoluenes, nitroglycerin, and various phthalates. The compounds were ionized in the MS source using simultaneous positive and negative electrospray ionization (ESI) with negative atmospheric pressure chemical ionization (APCI) in order to detect all compounds in a single analysis. The developed UPLC/MS/MS method was applied to commercially available smokeless powders and gunshot residue samples recovered from the hands of shooters, spent cartridges, and smokeless powder retrieved from unfired cartridges. Distinct compositions were identified for smokeless powders from different manufacturers and from separate manufacturing lots. The procedure also produced specific chemical profiles when tested on gunshot residues from different manufacturers. Overall, this thesis represents the development of a rapid and reproducible procedure capable of simultaneously detecting the widest possible range of components present in organic gunshot residue.^

Oxygen, pH and calcium dynamics and fluxes at the thallus surface under ambient (8.1) and low (7.8) seawater pH and across a range of irradiances

Presently, an incomplete mechanistic understanding of tropical reef macroalgae photosynthesis and calcification restricts predictions of how these important autotrophs will respond to global change. Therefore, we investigated the mechanistic link between inorganic carbon uptake pathways, photosynthesis and calcification in a tropical crustose coralline alga (CCA) using microsensors. We measured pH, oxygen (O2), and calcium (Ca2+) dynamics and fluxes at the thallus surface under ambient (8.1) and low (7.8) seawater pH (pHSW) and across a range of irradiances. Acetazolamide (AZ) was used to inhibit extracellular carbonic anhydrase (CAext), which mediates hydrolysis of HCO3-, and 4,4' diisothiocyanatostilbene-2,2'-disulphonate (DIDS) that blocks direct HCO3- uptake by anion exchange transport. Both inhibited photosynthesis, suggesting both diffusive uptake of CO2 via HCO3- hydrolysis to CO2 and direct HCO3- ion transport are important in this CCA. Surface pH was raised approximately 0.3 units at saturating irradiance, but less when CAext was inhibited. Surface pH was lower at pHSW 7.8 than pHSW 8.1 in the dark, but not in the light. The Ca2+ fluxes were large, complex and temporally variable, but revealed net Ca2+ uptake under all conditions. The temporal variability in Ca2+ dynamics was potentially related to localized dissolution during epithallial cell sloughing, a strategy of CCA to remove epiphytes. Simultaneous Ca2+ and pH dynamics suggest the presence of Ca2+/H+ exchange. Rapid light-induced H+ surface dynamics that continued after inhibition of photosynthesis revealed the presence of a light-mediated, but photosynthesis-independent, proton pump. Thus, the study indicates metabolic control of surface pH can occur in CCA through photosynthesis and light-inducible H+ pumps. Our results suggest that complex light-induced ion pumps play an important role in biological processes related to inorganic carbon uptake and calcification in CCA.