Comment mesurer les progrès de la lecture?

New observations of Neptune’s clouds in the near infrared were acquired in October 2013 with SINFONI on ESO’s Very Large Telescope (VLT) in Chile. SINFONI is an Integral Field Unit spectrometer returning a 64 × 64 pixel image with 2048 wavelengths. Image cubes in the J-band (1.09 – 1.41 μm) and H-band (1.43 – 1.87 μm) were obtained at spatial resolutions of 0.1″and 0.025″per pixel, while SINFONI’s adaptive optics provided an effective resolution of approximately 0.1″. Image cubes were obtained at the start and end of three successive nights to monitor the temporal development of discrete clouds both at short timescales (i.e. during a single night) as well as over the longer period of the three-day observing run. These observations were compared with similar H-band observations obtained in September 2009 with the NIFS Integral Field Unit spectrometer on the Gemini-North telescope in Hawaii, previously reported by Irwin et al., Icarus 216, 141-158, 2011, and previously unreported Gemini/NIFS observations at lower spatial resolution made in 2011. We find both similarities and differences between these observations, spaced over four years. The same overall cloud structure is seen with high, bright clouds visible at mid-latitudes (30 – 40°N,S), with slightly lower clouds observed at lower latitudes, together with small discrete clouds seen circling the pole at a latitude of approximately 60°S. However, while discrete clouds were visible at this latitude at both the main cloud deck level (at 2–3 bars) and in the upper troposphere (100–500mb) in 2009, no distinct deep (2–3 bar), discrete circumpolar clouds were visible in 2013, although some deep clouds were seen at the southern edge of the main cloud belt at 30–40°S, which have not been observed before. The nature of the deep sub-polar discrete clouds observed in 2009 is intriguing. While it is possible that in 2013 these deeper clouds were masked by faster moving, overlying features, we consider that it is unlikely that this should have happened in 2013, but not in 2009 when the upper-cloud activity was generally similar. Meanwhile, the deep clouds seen at the southern edge of the main cloud belt at 30 – 40°S in 2013, should also have been detectable in 2009, but were not seen. Hence, these observations may have detected a real temporal variation in the occurrence of Neptune’s deep clouds, pointing to underlying variability in the convective activity at the pressure of the main cloud deck at 2–3 bars near Neptune’s south pole and also in the main observable cloud belt at 30 – 40°S.</p

The Development and Use of A Piloted Flight Simulation Environment for Rotary-Wing Operation to the Queen Elizabeth Class Aircraft Carriers

Flight simulation is being used to inform the First of Class Flight Trials for the UK’s new Queen Elizabeth Class (QEC) aircraft carriers. The carriers will operate with the Lockheed Martin F-35B Lightning II fighter aircraft, i.e. the Advanced Short Take-Off and Vertical Landing variant of the F-35. The rotary wing assets that are expected to operate with QEC include Merlin, Wildcat, Chinook and Apache helicopters. An F-35B flight simulator has been developed and is operated by BAE Systems at Warton Aerodrome. The University of Liverpool is supporting this project by using Computational Fluid Dynamics (CFD) to provide the unsteady air flow field that is required in a realistic flight simulation environment. This paper is concerned with a research project that is being conducted using the University’s research simulator, HELIFLIGHT-R, to create a simulation environment for helicopter operations to the QEC. The paper briefly describes how CFD has been used to model the unsteady airflow over the 280m long aircraft carrier and how this is used to create a realistic flight simulation environment. Results are presented from an initial simulation trial in which test pilots have used the HELIFLIGHT-R simulator to conduct simulated helicopter landings to two landing spots on the carrier, one in a disturbed air flow and the other in clean air. As expected, the landing to the spot in disturbed air flow requires a greater pilot workload, shows greater deviation in its positional accuracy and requires more control activity. This initial trial is the first of a planned series of simulated helicopter deck landings for different wind angles and magnitudes

A Virtual Engineering Approach to the Ship-Helicopter Dynamic Interface; a decade of modelling and simulation research at The University of Liverpool

This paper reviews some of the research that has been carried out at the University of Liverpool where the Flight Science and Technology Research Group has developed its Heliflight-R full-motion research simulator to create a simulation environment for the launch and recovery of maritime helicopters to ships. HELIFLIGHT-R has been used to conduct flight trials to produce simulated Ship-Helicopter Operating Limits (SHOLs). This virtual engineering approach has led to a much greater understanding of how the dynamic interface between the ship and the helicopter contributes to the pilot's workload and the aircraft's handling qualities and will inform the conduct of future real-world SHOL trials. The paper also describes how modelling and simulation has been applied to the design of a ship's superstructure to improve the aerodynamic flow field in which the helicopter has to operate. The superstructure aerodynamics also affects the placement of the ship's anemometers and the dispersion of the ship's hot exhaust gases, both of which affect the operational envelope of the helicopter, and both of which can be investigated through simulation

Use of surface testing devices to identify potential risk factors for synthetic equestrian surfaces

Mechanical properties of sports surfaces have previously been shown to be influenced by surface drainage, moisture content and compaction but these factors have not yet been quantified for equestrian surfaces. The aim of the study was to examine the effect of three moisture levels (11.96 ± 1.63%, 17.31 ± 1.14%, 19.08 ± 0.78%) and three rates of compaction (1.647±0.02 g/cm3, 1.748±0.046 g/cm3, 1.766±0.039 g/cm3) on the functional properties of a synthetic equestrian surface constructed over two distinct drainage profiles. The surfaces with a high (19.08%) moisture content and medium density when laid on permavoid™ had the most favourable results when taking into account all of the measured parameters with regards to reducing the risk of injury yet potentially offering sufficient support to the horse for efficient locomotion

Contaminants in Commercial Preparations of ‘Purified’ Small Leucine-Rich Proteoglycans May Distort Mechanistic Studies

This paper reports the perplexing results that came about because of seriously impure commercially available reagents. Commercial reagents and chemicals are routinely ordered by scientists and are expected to have been rigorously assessed for their purity. Unfortunately, we found this assumption to be risky. Extensive work was carried out within our laboratory using commercially-sourced preparations of the small leucine-rich proteoglycans, decorin and biglycan, to investigate their influence on nerve cell growth. Unusual results compelled us to analyse the composition and purity of both preparations of these proteoglycans using both mass spectrometry and Western blotting, with and without various enzymatic deglycosylations. Commercial ‘decorin’ and ‘biglycan’ were found to contain a mixture of proteoglycans including not only both decorin and biglycan but also fibromodulin and aggrecan. The unexpected effects of ‘decorin’ and ‘biglycan’ on nerve cell growth could be explained by these impurities. Decorin and biglycan contain either chondroitin or dermatan sulphate glycosaminoglycan chains whilst fibromodulin only contains keratan sulphate and the large (>2,500 kDa), highly glycosylated aggrecan, contains both keratan and chondroitin sulphate. The different structure, molecular weights and composition of these impurities significantly affected our work and any conclusions that could be made. These findings beg the question as to whether scientists need to verify the purity of each commercially obtained reagent used in their experiments. The implications of these findings are vast, since the effects of these impurities may already have led to inaccurate conclusions and reports in the literature with concomitant loss of researchers’ funds and time

Prophylactic radiotherapy against heterotopic ossification following internal fixation of acetabular fractures: a comparative estimate of risk.

OBJECTIVE: Radiotherapy (RT) is effective in preventing heterotopic ossification (HO) around acetabular fractures requiring surgical reconstruction. We audited outcomes and estimated risks from RT prophylaxis, and alternatives of indometacin or no prophylaxis. METHODS: 34 patients underwent reconstruction of acetabular fractures through a posterior approach, followed by a 8-Gy single fraction. The mean age was 44 years. The mean time from surgery to RT was 1.1 days. The major RT risk is radiation-induced fatal cancer. The International Commission on Radiological Protection (ICRP) method was used to estimate risk, and compared with a method (Trott and Kemprad) specifically for estimating RT risk for benign disease. These were compared with risks associated with indometacin and no prophylaxis. RESULTS: 28 patients (82%) developed no HO; 6 developed Brooker Class I; and none developed Class II-IV HO. The ICRP method suggests a risk of fatal cancer in the range of 1 in 1000 to 1 in 10,000; the Trott and Kemprad method suggests 1 in 3000. For younger patients, this may rise to 1 in 2000; and for elderly patients, it may fall to 1 in 6000. The risk of death from gastric bleeding or perforation from indometacin is 1 in 180 to 1 in 900 in older patients. Without prophylaxis risk of death from reoperation to remove HO is 1 in 4000 to 1 in 30,000. CONCLUSION: These results are encouraging, consistent with much larger series and endorse our multidisciplinary management. Risk estimates can be used in discussion with patients. ADVANCES IN KNOWLEDGE: The risk from RT prophylaxis is small, it is safer than indometacin and substantially overlaps with the range for no prophylaxis.NGB is supported by the National Institute for Health Research (NIHR) Cambridge Biomedical Research Centre. JES is supported by Cancer Research UK through the Cambridge Cancer Centre.This is the accepted manuscript version. The final version is available from the BIR at http://www.birpublications.org/doi/abs/10.1259/bjr.20140398?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%3dpubmed&

Family and home correlates of children's physical activity in a multi-ethnic population: the cross-sectional Child Heart and Health Study in England (CHASE).

BACKGROUND: The influence of the family and home environment on childhood physical activity (PA) and whether this differs between ethnic groups remains uncertain. This paper investigates associations between family and home factors and childhood PA in a multi-ethnic population and explores whether associations differ between ethnic groups. METHODS: Cross-sectional study of 9-10 year-old schoolchildren, in which PA was objectively measured by Actigraph GT1 M accelerometers for ≤7 days to estimate average activity counts per minute (CPM). Information on 11 family and home environmental factors were collected from questionnaires. Associations between these factors and CPM were quantified using multi-level linear regression. Interactions with ethnicity were explored using likelihood ratio tests. RESULTS: 2071 children (mean ± SD age: 9.95 ± 0.38 years; 47.8% male) participated, including 25% white European, 28% black African-Caribbean, 24% South Asian, and 24% other ethnic origin. Family PA support and having a pet were associated with higher average CPM (adjusted mean difference: 6 (95%CI:1,10) and 13 (95%CI:3,23), respectively) while car ownership and having internet access at home were associated with lower average CPM (adjusted mean difference: -19 (95%CI:-30,-8) and -10 (95%CI:-19,0), respectively). These associations did not differ by ethnicity. Although the number of siblings showed no overall association with PA, there was some evidence of interaction with ethnicity (p for ethnicity interaction=0.04, 0.05 in a fully-adjusted model); a positive significant association with number of siblings was observed in white Europeans (per sibling CPM difference 10.3 (95% CI 1.7, 18.9)) and a positive non-significant association was observed in black African-Caribbeans (per sibling CPM difference: 3.5 (-4.2, 11.2)) while a negative, non-significant association was observed in South Asians (per sibling CPM difference -6.0 (-15.5, 3.4)). CONCLUSIONS: Some family and home environmental factors have modest associations with childhood PA and these are mostly similar across different ethnic groups. This suggests that targeting these factors in an intervention to promote PA would be relevant for children in different ethnic groups.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

A numerical study of the r-mode instability of rapidly rotating nascent neutron stars

The first results of numerical analysis of classical r-modes of {\it rapidly} rotating compressible stellar models are reported. The full set of linear perturbation equations of rotating stars in Newtonian gravity are numerically solved without the slow rotation approximation. A critical curve of gravitational wave emission induced instability which restricts the rotational frequencies of hot young neutron stars is obtained. Taking the standard cooling mechanisms of neutron stars into account, we also show the `evolutionary curves' along which neutron stars are supposed to evolve as cooling and spinning-down proceed. Rotational frequencies of $1.4M_{\odot}$ stars suffering from this instability decrease to around 100Hz when the standard cooling mechanism of neutron stars is employed. This result confirms the results of other authors who adopted the slow rotation approximation.Comment: 4 pages, 2 figures; MNRAS,316,L1(2000

Spin and orbital states in La1.5 Sr0.5 CoO4 studied by electronic structure calculations

Electronic structure of the layered perovskite La1.5Sr0.5CoO4 with a checkerboard Co2+/Co3+ charge order is studied, using the local-spin-density approximation plus Hubbard U calculations including also the spin-orbit coupling and multiplet effect. Our results show that the Co2+ ion is in a high spin state (HS, t(2g)(5)e(g)(2)) and Co3+ low spin state (LS, t(2g)(6)). Due to a small Co2+ t(2g) crystal field splitting, the spin-orbit interaction produces an orbital moment of 0.26 mu(B) and accounts for the observed easy in-plane magnetism. Moreover, we find that the Co3+ intermediate spin state (IS, t(2g)(5)e(g)(1)) has a multiplet splitting of several tenths of eV and the lowest-lying one is still higher than the LS ground state by 120 meV, and that the Co3+ HS state (t(2g)(4)e(g)(2)) is more unstable by 310 meV. Either the IS or HS Co3+ ions would give rise to a wrong magnetic order and anisotropy

The Role of Modelling and Simulation in the Preparations for Flight Trials Aboard the Queen Elizabeth Class Aircraft Carriers

This paper provides a brief overview of how modelling and simulation has been used to inform preparations for First of Class Flight Trials (FOCFT) aboard HMS Queen Elizabeth, the first of the United Kingdom’s two new Queen Elizabeth Class aircraft carriers, from the perspective of a collaborative research programme undertaken by industry and academia to develop high-fidelity simulations of the carrier’s ‘airwake’.  Computer modelling of the unsteady air flow over the carrier, and of the aircraft flight dynamics, have been integrated into high-fidelity flight simulators at BAE Systems Warton, and at the University of Liverpool.  The Queen Elizabeth Class (QEC) carriers have primarily been designed to operate the Short Take-Off and Vertical Landing (STOVL) variant of the Lockheed Martin F-35 Lightning II multirole fighter aircraft and will also operate a range of rotary-wing assets.  Computational Fluid Dynamics (CFD) has been used to compute the time-varying air flow over and around the 280m long ship, along the F-35B landing approach path and up to 400m astern of the ship.  The paper shows a selection of results from the full-scale CFD analysis, and the results from a small-scale experiment that was conducted to provide confidence in the validity of the computed airwakes.  The QEC airwakes have been employed by BAE Systems in its fixed-wing flight simulator at Warton, where test pilots have conducted simulated deck landings for a variety of wind over deck conditions, so providing experience for F-35B test pilots and the ship’s Flying Control (FLYCO) crew ahead of FOCFT, which will be conducted later this year.  Airwakes have also been implemented in the HELIFLIGHT-R flight simulator at the University of Liverpool, where helicopter landings to the QEC have been simulated using a generic medium-weight maritime-helicopter model. A selection of results from the helicopter flight simulator trials is presented in terms of the workload ratings reported by test pilots, and these are related to the characteristics of the computed airwake at the landing spots tested.  The paper demonstrates how modelling and simulation can be used to reduce both the risk and cost of flight trials, by informing the FOCFT planning process, and by highlighting, in advance of the trials, which wind speed and azimuth combinations may require more focus.  </jats:p