Determination of gas volume trapped in a closed fluid system

Technique involves extracting known volume of fluid and measuring system before and after extraction, volume of entrapped gas is then computed. Formula derived from ideal gas laws is basis of this method. Technique is applicable to thermodynamic cycles and hydraulic systems

Development of catalysts for asymmetric hydrogenation

The application of tetradentate aminoalcohol ligands to the KOtBu-catalysed hydrogenation of benzophenone has been studied. Hydrogenation was found to proceed via a transfer hydrogenation process with the ligands acting as hydrogen donors. A series of bidentate and tetradentate ligands containing a variety of coordinating groups including amino, hydroxy, silyl, phosphine and amido functionalities have been prepared and applied to the transition metal-catalysed asymmetric transfer hydrogenation of ketones using iron, ruthenium and rhodium metals although none were found to be enantioselective for the hydrogenation of acetophenone. A series of asymmetric tethered ruthenium half sandwich complexes have been applied to the asymmetric pressure hydrogenation of ketones. Studies have investigated the effect of changing the sulfonamide group, halide and tether length on the activity of the catalysts. The application of an achiral tethered ruthenium half sandwich complex as a catalyst for the pressure hydrogenation of aldehydes is also reported. A novel synthesis of tethered ruthenium complexes using aryl substitution methodology has been developed and applied to the preparation of a series of novel complexes which were found to be highly active for asymmetric pressure hydrogenation of ketones. The application of the synthesis to the preparation of poly(methyl methacrylate) supported complexes is also discussed. Application of the supported catalysts to asymmetric pressure and transfer hydrogenation of acetophenone has shown potential for the development of an active heterogeneous catalyst for transfer hydrogenation of ketones in aqueous media

Frontier exploration and the North Atlantic Igneous Province : new insights from a 2.6 km offshore volcanic sequence in the NE Faroe–Shetland Basin

Acknowledgements and Funding This work was funded by Chevron. The authors would like to acknowledge the Chevron West of Shetlands team along with the Joint Venture partners OMV, Faroe Petroleum and Indemitsu for access to data along with permission to publish this study. PGS is thanked for access to the Corona Ridge Regional Geostreamer (CRRG) data and permission to publish the seismic line. The paper was improved thanks to insightful reviews by S. M. Jones and A. Saunders, which substantially improved an earlier draft. J. Still and F. Thompson gave invaluable technical support at the University of Aberdeen, and K. Wall helped with real-time cuttings analysis.Peer reviewedPostprin

Organic geochemistry of the crater-fill sediments from Boltysh impact crater, Ukraine

The Boltysh impact crater, is a complex structure formed on the basement rocks of the Ukrainian shield which has been dated at 65.17±0.64 Ma [1]. The Boltysh crater has been know for several decades and was originally drilled in the 1960s-1980s in a study of economic oil shale deposits. Unfortunately, the cores were not curated and have been lost. However we have recently re-drilled the impact crater and have recovered a near continuous record of ~400 m of organic rich sediments deposited in a deep isolated lake which overlie the basement rocks spanning a period ~10 Ma. At 24km diameter, Boltysh will not have contributed substantially to the worldwide devastation at the end of the Cretaceous. However, the precise age of the Boltysh impact relative to the Chicxulub impact and its location on a stable low lying coastal plain which allowed formation of the postimpact crater lake make it a particularly important locality. After the impact, the crater quickly filled with water in a short marine phase but returned to fresh water which persisted for >10Ma [2]. These strata contain a valuable record of Paleogene environmental change in central Europe, and one of very few terrestrial records of the KT event. This pre-eminent record of the Paleogene can help us to answer several related scientific questions including the relative age of Boltysh compared with Chicxulub, recovery from the impact, and later climate signals. The organic geochemistry and playnology indicate main inputs to be algal and higher plant within most of the core although there are some marked changes in inputs in some sections. A number of carbon isotope excursions are also present within the core which are currently being further investigated

Accretion Discs in Blazars

The characteristic properties of blazars (rapid variability, strong polarization, high brightness) are widely attributed to a powerful relativistic jet oriented close to our line of sight. Despite the spectral energy distributions (SEDs) being strongly jet-dominated, a "big blue bump" has been recently detected in sources known as flat spectrum radio quasars (FSRQs). These new data provide a unique opportunity to observationally test coupled jet-disc accretion models in these extreme sources. In particular, as energy and angular momentum can be extracted by a jet magnetically coupled to the accretion disc, the thermal disc emission spectrum may be modified from that predicted by the standard model for disc accretion. We compare the theoretically predicted jet-modified accretion disc spectra against the new observations of the "big blue bump" in FSRQs. We find mass accretion rates that are higher, typically by a factor of two, than predicted by standard accretion disc theory. Furthermore, our results predict that the high redshift blazars PKS 0836+710, PKS 2149-307, B2 0743+25 and PKS 0537-286 may be predominantly powered by a low or moderate spin (a < 0.6) black hole with high mass accretion rates mdot_a ~ 50 - 200 msol/yr, while 3C 273 harbours a rapidly spinning black hole (a = 0.97) with mdot_a ~ 20 msol/yr. We also find that the black hole masses in these high redshift sources must be > 5 * 10^9 msol.Comment: Accepted for publication (17 August 2009) in MNRA

Making the Most of Interim Assessment Data: Lessons from Philadelphia

Under No Child Left Behind, urban school districts have increasingly turned to interim assessments, administered at regular intervals, to help gauge student progress in advance of annual state exams. These assessments have spawned growing debate among educators, assessment experts, and the testing industry: are they worth the significant investment of money and time? In Making the Most of Interim Assessment Data: Lessons from Philadelphia, Research for Action (RFA) weighs in on this issue. The School District of Philadelphia (SDP) was an early adopter of interim assessments, implementing the exams in 2003. Unlike teachers in some other regions, Philadelphia elementary and middle grades teachers rated these 'Benchmark' assessments highly. However, the study found that enthusiasm did not necessarily correlate with higher rates of student achievement. What did predict student success were three factors -- instructional leadership, collective responsibility, and use of the SDP's Core Curriculum. The report underscores the value of investment in ongoing data interpretation that emphasizes teachers' learning within formal instructional communities, such as grade groups of teachers. This research was funded by the Spencer Foundation and the William Penn Foundation

Tethered Ru(II) catalysts containing a Ru–I bond

Two new iodide-containing derivatives of the widely-adopted arene/Ru(II)/TsDPEN catalysts have been prepared and fully characterised, including through X-ray crystallography. They have been evaluated as catalysts for the asymmetric reduction of acetophenone under both transfer (ATH) and pressure hydrogenation (AH) conditions. The iodide-containing complexes are equally efficient in the ATH reaction, but less active in the AH reaction compared to the chloride derivatives

Assessing the prevalence of refractive errors and accuracy of vision screening by schoolteachers in Liberia

Background Evidence indicates that school-based vision screening by trained teachers is an effective way of identifying and addressing potential vision problems in schoolchildren. However, inconsistencies have been reported in both the testing methods and accuracy of the screeners. This study assessed the prevalence of refractive errors and accuracy of screening by teachers in Grand Kru County, Liberia. Methods We conducted a retrospective analysis of data from four schools where, in February 2019, children were screened for refractive errors by trained teachers and then re-examined by ophthalmic technicians. One row of five optotypes of the Snellen 6/9 (0.2 logMar) scale (tumbling E chart) was used at a distance of 3 m. The prevalence of visual impairment and associations with sex, age and school were explored. Sensitivity, specificity and predictive values were calculated. Results Data were available for 823 of 1095 eligible children with a mean age of 13.7 y (range 5–18) and male:female ratio of 1:0.8. Poor vision was identified in 24 (2.9%) children with no differences by either sex or age but small differences by school. Screening by teachers had a sensitivity of 0.25 (95% confidence interval [CI] 0.077 to 0.423) and a specificity of 0.996 (95% CI 0.992 to 1.000). Positive and negative predictive values were 0.667 (95% CI 0.359 to 0.975) and 0.978 (95% CI 0.968 to 0.988), respectively. The results were influenced by a high number of misclassifications in one of the four schools. Conclusions Teachers can be trained to conduct vision screening tests on schoolchildren to an acceptable level of accuracy, but strong monitoring and quality assurance systems should be built into screening programmes from the onset. In settings like Liberia, where many children do not attend school regularly, screening programmes should extend to community platforms to reach children out of school