Re-estimation of argon isotope ratios leading to a revised estimate of the Boltzmann constant

In 2013, NPL, SUERC and Cranfield University published an estimate for the Boltzmann constant [1] based on a measurement of the limiting low-pressure speed of sound in argon gas. Subsequently, an extensive investigation by Yang et al [2] revealed that there was likely to have been an error in the estimate of the molar mass of the argon used in the experiment. Responding to [2], de Podesta et al revised their estimate of the molar mass [3]. The shift in the estimated molar mass, and of the estimate of kB, was large: -2.7 parts in 106, nearly four times the original uncertainty estimate. The work described here was undertaken to understand the cause of this shift and our conclusion is that the original samples were probably contaminated with argon from atmospheric air.
 In this work we have repeated the measurement reported in [1] on the same gas sample that was examined in [2, 3]. However in this work we have used a different technique for sampling the gas that has allowed us to eliminate the possibility of contamination of the argon samples. We have repeated the sampling procedure three times, and examined samples on two mass spectrometers. This procedure confirms the isotopic ratio estimates of Yang et al [2] but with lower uncertainty, particularly in the relative abundance ratio R38:36.
 Our new estimate of the molar mass of the argon used in Isotherm 5 in [1] is 39.947 727(15) g mol-1 which differs by +0.50 parts in 106 from the estimate 39.947 707(28) g mol-1 made in [3]. This new estimate of the molar mass leads to a revised estimate of the Boltzmann constant of kB = 1.380 648 60 (97) × 10−23 J K−1 which differs from the 2014 CODATA value by +0.05 parts in 106.&#13

Increase in Legionnaires' disease cases associated with travel to Dubai among travellers from the United Kingdom, Sweden and the Netherlands, October 2016 to end August 2017.

Between 1 October 2016 and 31 August 2017, 51 Legionnaires' disease (LD) cases from the United Kingdom, Sweden and the Netherlands were identified with associated travel to Dubai. Cases did not all stay in the same accommodation, indicating that no single accommodation could be the source for all these infections. While local investigations continue into other potential sources, clinicians should remain alert to the possibility of LD among travellers returning from Dubai with respiratory illness

Systematic review and network meta-analysis on the efficacy of evolocumab and other therapies for the management of lipid levels in hyperlipidemia

Background: The proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors evolocumab and alirocumab substantially reduce low‐density lipoprotein cholesterol (LDL‐C) when added to statin therapy in patients who need additional LDL‐C reduction. Methods and Results: We conducted a systematic review and network meta‐analysis of randomized trials of lipid‐lowering therapies from database inception through August 2016 (45 058 records retrieved). We found 69 trials of lipid‐lowering therapies that enrolled patients requiring further LDL‐C reduction while on maximally tolerated medium‐ or high‐intensity statin, of which 15 could be relevant for inclusion in LDL‐C reduction networks with evolocumab, alirocumab, ezetimibe, and placebo as treatment arms. PCSK9 inhibitors significantly reduced LDL‐C by 54% to 74% versus placebo and 26% to 46% versus ezetimibe. There were significant treatment differences for evolocumab 140 mg every 2 weeks at the mean of weeks 10 and 12 versus placebo (−74.1%; 95% credible interval −79.81% to −68.58%), alirocumab 75 mg (−20.03%; 95% credible interval −27.32% to −12.96%), and alirocumab 150 mg (−13.63%; 95% credible interval −22.43% to −5.33%) at ≥12 weeks. Treatment differences were similar in direction and magnitude for PCSK9 inhibitor monthly dosing. Adverse events were similar between PCSK9 inhibitors and control. Rates of adverse events were similar between PCSK9 inhibitors versus placebo or ezetimibe. Conclusions: PCSK9 inhibitors added to medium‐ to high‐intensity statin therapy significantly reduce LDL‐C in patients requiring further LDL‐C reduction. The network meta‐analysis showed a significant treatment difference in LDL‐C reduction for evolocumab versus alirocumab

A problem solving system employing a formal approach to means

The thesis describes the theory and design of a general problem-solving system. The system uses a single general heuristic based on a formal definition of differences within the framework of means/ends analysis and employs tree search during problem solution. A comparison is made with two other systems using means/ends analysis. The conditions under which the system is capable of solving problems are investigated and the efficiency of the system is considered. The system has solved a variety of problems of varying complexity and the difference heuristic appears comparatively accurate for goal-directed search within certain limits

Stocktake and analysis of legume evaluation for tropical pastures in Australia

There has been a large effort dedicated to the evaluation of a wide variety of sub-tropical and tropical pasture legumes in the past. This large body of information is very valuable for guiding any future legume development activities, yet much of this information was at risk of being lost. This project aimed to collate and store this tropical legume evaluation data and use this and knowledge from past researchers to recommend priority R&D approaches and activities for future pasture legume development. Together with retired pasture researchers, legume evaluation datasets were identified, prioritised, and collated into a database which captured over 180 000 data records collected from 567 sites across northern Australia. Using this large integrated dataset, high power statistical approaches were used to identify legume species which performed well across this large range of evaluation sites. Several species and genera were identified which warrant further investigation and further in-depth analysis of the database in species or genera of interest would be valuable. A gap analysis of commercially proven, underused and prospective legumes was conducted across the key production regions of northern Australia. A range of material was identified which could offer potential improvements in seed production, cold, drought or grazing tolerance compared to the current released varieties

European support for the opposition to closer union of the Rhodesias and Nyasaland, with special reference to the period from 1945-1953

This dissertation is a study of the interplay of Imperial, Colonial and Settler politics in support of, and in opposition to the establishment of a united white ruled central Africa. Accordingly, consideration of African involvement arises only as it affected the other groups. This is not in any way to belittle the significance of African activity in the period - activity which has been studied in depth by other authors - it is simply a consequence of the aspect of the problem I have chosen to address

Genetic Background Can Result in a Marked or Minimal Effect of Gene Knockout (GPR55 and CB2 Receptor) in Experimental Autoimmune Encephalomyelitis Models of Multiple Sclerosis

PMCID: PMC379391

EFFECTS OF IMPOSED CYCLE FREQUENCY TRAINING ON THE HEAVE AND PITCH PHASE RELATIONSHIPS IN UNDULATORY UNDERWATER SWIMMING

This study compared the effects of training at a self-selected preferred cycle frequency (PF) with an identical imposed cycle frequency (IF) on the heave and pitch phase relationship in undulatory underwater swimming (UUS), to examine the effects of frequency imposition on coordination. Kinematic data were recorded from 16 skilled swimmers performing maximal UUS prior to and during 4-weeks UUS training at either their PF or an IF set at their preferred frequency, with weekly testing sessions and final retest session 2-weeks post training. No differences in maximal swimming velocity were found. No differences were found in heave and pitch phase relationship between training groups. Further research is required to establish the efficacy of heave and pitch coupling as an effective measure of UUS behaviour in skilled swimmers