3,107 research outputs found

    Assessment of valley cold pools and clouds in a very high-resolution numerical weather prediction model

    Get PDF
    The formation of cold air pools in valleys under stable conditions represents an important challenge for numerical weather prediction (NWP). The challenge is increased when the valleys that dominate cold pool formation are on scales unresolved by NWP models, which can lead to substantial local errors in temperature forecasts. In this study a 2-month simulation is presented using a nested model con- figuration with a finest horizontal grid spacing of 100 m. The simulation is compared with observations from the recent COLd air Pooling Experiment (COLPEX) project and the model’s ability to represent cold pool formation, and the surface energy balance is assessed. The results reveal a bias in the model long-wave radiation that results from the assumptions made about the sub-grid variability in humidity in the cloud parametrization scheme. The cloud scheme assumes relative humidity thresholds below 100 % to diagnose partial cloudiness, an approach common to schemes used in many other models. The biases in radiation, and resulting biases in screen temperature and cold pool properties are shown to be sensitive to the choice of critical relative humidity, suggesting that this is a key area that should be improved for very high-resolution modeling

    A case‐study of cold‐air pool evolution in hilly terrain using field measurements from COLPEX

    Get PDF
    A case‐study investigation of cold‐air pool (CAP) evolution in hilly terrain is conducted using field measurements made during IOP 16 of the COLd‐air Pool EXperiment (COLPEX). COLPEX was designed to study cold‐air pooling in small‐scale valleys typical of the UK (∼100–200 m deep, ∼1 km wide). The synoptic conditions during IOP 16 are typical of those required for CAPs to form during the night, with high pressure, clear skies and low ambient winds. Initially a CAP forms around sunset and grows uninterrupted for several hours. However, starting 4 hr after sunset, a number of interruptions to this steady cooling rate occur. Three episodes are highlighted from the observations and the cause of disruption attributed to (a) wave activity, in the form of gravity waves and/or Kelvin–Helmholtz (KH) instability, (b) increases in the above‐valley winds resulting from the development of a nocturnal low‐level jet (NLLJ), (c) shear‐induced mixing resulting from instability of the NLLJ. A weakly stable residual layer provides the conditions for wave activity during Episode 1. This residual layer is eroded by a developing NLLJ from the top down during Episode 2. The sustained increase in winds at hill‐top levels – attributed to the NLLJ – continue to disrupt the CAP through Episode 3. Although cooling is interrupted, the CAP is never completely eroded during the night. Complete CAP break‐up occurs some 3.5 hr after local sunrise. This case‐study highlights a number of meteorological phenomena that can disrupt CAP evolution even in ideal CAP conditions. These processes are unlikely to be sufficiently represented by current operational weather forecast models and can be challenging even for high‐resolution research models

    Numerical analysis of the integration of wind turbines into the design of the built environment

    No full text
    The effect of wind distribution on the architectural domain of the Bahrain Trade Centre was numerically analysed using Computational Fluid Dynamics (CFD). Using the numerical data, the power generation potential of the building integrated wind turbines was determined in response to the prevailing wind direction. Simulating a reference wind speed of 6 m/s, the findings from the study quantified an estimate power generation of 6.4 kW indicating a capacity factor of 2.9% for the computational model. At the windward side of the building, it was observed that the layers of turbulence intensified in inverse proportion to the height of the building with an average value of 0.45 J/kg. The air velocity was found to gradually increase in direct proportion to the elevation with the turbine located at higher altitude receiving maximum exposure to incoming wind. This study highlighted the potential of using advanced computational fluid dynamics in order to factor wind into the design of any architectural environment

    Humanizing harm: Using a restorative approach to heal and learn from adverse events

    Get PDF
    Background: Healthcare is not without risk. Despite two decades of policy focus and improvement efforts, the global incidence of harm remains stubbornly persistent, with estimates suggesting that 10% of hospital patients are affected by adverse events. Methods: We explore how current investigative responses can compound the harm for all those affected—patients, families, health professionals and organizations—by neglecting to appreciate and respond to the human impacts. We suggest that the risk of compounded harm may be reduced when investigations respond to the need for healing alongside system learning, with the former having been consistently neglected. Discussion: We argue that incident responses must be conceived within a relational as well as a regulatory framework, and that this—a restorative approach—has the potential to radically shift the focus, conduct and outcomes of investigative processes. Conclusion: The identification of the preconditions and mechanisms that enable the success of restorative approaches in global health systems and legal contexts is required if their demonstrated potential is to be realized on a larger scale. The policy must be co-created by all those who will be affected by reforms and be guided by restorative principles. Patient or Public Contribution: This viewpoint represents an international collaboration between a clinician academic, safety scientist and harmed patient and family members. The paper incorporates key findings and definitions from New Zealand's restorative response to surgical mesh harm, which was co-designed with patient advocates, academics and clinicians

    Advanced Cardiac Resuscitation Evaluation (ACRE): A randomised single-blind controlled trial of peer-led vs. expert-led advanced resuscitation training

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Advanced resuscitation skills training is an important and enjoyable part of medical training, but requires small group instruction to ensure active participation of all students. Increases in student numbers have made this increasingly difficult to achieve.</p> <p>Methods</p> <p>A single-blind randomised controlled trial of peer-led vs. expert-led resuscitation training was performed using a group of sixth-year medical students as peer instructors. The expert instructors were a senior and a middle grade doctor, and a nurse who is an Advanced Life Support (ALS) Instructor.</p> <p>A power calculation showed that the trial would have a greater than 90% chance of rejecting the null hypothesis (that expert-led groups performed 20% better than peer-led groups) if that were the true situation. Secondary outcome measures were the proportion of High Pass grades in each groups and safety incidents.</p> <p>The peer instructors designed and delivered their own course material. To ensure safety, the peer-led groups used modified defibrillators that could deliver only low-energy shocks.</p> <p>Blinded assessment was conducted using an Objective Structured Clinical Examination (OSCE). The checklist items were based on International Liaison Committee on Resuscitation (ILCOR) guidelines using Ebel standard-setting methods that emphasised patient and staff safety and clinical effectiveness.</p> <p>The results were analysed using Exact methods, chi-squared and t-test.</p> <p>Results</p> <p>A total of 132 students were randomised: 58 into the expert-led group, 74 into the peer-led group. 57/58 (98%) of students from the expert-led group achieved a Pass compared to 72/74 (97%) from the peer-led group: Exact statistics confirmed that it was very unlikely (p = 0.0001) that the expert-led group was 20% better than the peer-led group.</p> <p>There were no safety incidents, and High Pass grades were achieved by 64 (49%) of students: 33/58 (57%) from the expert-led group, 31/74 (42%) from the peer-led group. Exact statistics showed that the difference of 15% meant that it was possible that the expert-led teaching was 20% better at generating students with High Passes.</p> <p>Conclusions</p> <p>The key elements of advanced cardiac resuscitation can be safely and effectively taught to medical students in small groups by peer-instructors who have undergone basic medical education training.</p

    Exploring the behavioural drivers of veterinary surgeon antibiotic prescribing: a qualitative study of companion animal veterinary surgeons in the UK

    Get PDF
    Background: Multi-drug resistant bacteria are an increasing concern in both human and veterinary medicine. Inappropriate prescribing and use of antibiotics within veterinary medicine may be a contributory factor to antimicrobial resistance (AMR). The ‘One Health’ Initiative aims to work across species and environments to reduce AMR, however; little is currently known about the factors which influence antibiotic prescribing among veterinary surgeons in companion animal practice. This paper reports on qualitative data analysis of interviews with veterinary surgeons whose practice partially or wholly focuses on companion animals (N = 16). The objective of the research was to explore the drivers of companion animal veterinary surgeons’ antibiotic prescribing behaviours. The veterinary surgeons interviewed were all practising within the UK (England (n = 4), Scotland (n = 11), Northern Ireland (n = 1)). A behavioural thematic analysis of the data was undertaken, which identified barriers and facilitators to specific prescribing-related behaviours. Results: Five components of prescribing behaviours were identified: 1) confirming clinical need for antibiotics; 2) responding to clients; 3) confirming diagnosis; 4) determining dose, duration and type of antibiotic; and 5) preventing infection around surgery (with attendant appropriate and inappropriate antibiotic prescribing behaviours). Barriers to appropriate prescribing identified include: business, diagnostic, fear, habitual practice and pharmaceutical factors. Facilitators include: AMR awareness, infection prevention, professional learning and regulation and government factors. Conclusion: This paper uses a behavioural lens to examine drivers which are an influence on veterinary surgeons’ prescribing behaviours. The paper contributes new understandings about factors which influence antibiotic prescribing behaviours among companion animal veterinary surgeons. This analysis provides evidence to inform future interventions, which are focused on changing prescribing behaviours, in order to address the pressing public health concern of AMR

    Adolescents’ responses to the promotion and flavouring of e-cigarettes

    Get PDF
    Objectives The purpose of the study is to examine adolescents’ awareness of e-cigarette marketing and investigate the impact of e-cigarette flavour descriptors on perceptions of product harm and user image. Methods Data come from the 2014 Youth Tobacco Policy Survey, a cross-sectional in-home survey conducted with 11–16 year olds across the UK (n = 1205). Adolescents’ awareness of e-cigarette promotion, brands, and flavours was assessed. Perceptions of product harm, and likely user of four examples of e-cigarette flavours was also examined. Results Some participants had tried e-cigarettes (12 %) but regular use was low (2 %) and confined to adolescents who had also smoked tobacco. Most were aware of at least one promotional channel (82 %) and that e-cigarettes came in different flavours (69 %). Brand awareness was low. E-cigarettes were perceived as harmful (M = 3.54, SD = 1.19) but this was moderated by product flavours. Fruit and sweet flavours were perceived as more likely to be tried by young never smokers than adult smokers trying to quit (p < 0.001). Conclusions There is a need to monitor the impact of future market and regulatory change on youth uptake and perceptions of e-cigarettes

    Wolbachia in the flesh: symbiont intensities in germ-line and somatic tissues challenge the conventional view of Wolbachia transmission routes

    Get PDF
    Symbionts can substantially affect the evolution and ecology of their hosts. The investigation of the tissue-specific distribution of symbionts (tissue tropism) can provide important insight into host-symbiont interactions. Among other things, it can help to discern the importance of specific transmission routes and potential phenotypic effects. The intracellular bacterial symbiont Wolbachia has been described as the greatest ever panzootic, due to the wide array of arthropods that it infects. Being primarily vertically transmitted, it is expected that the transmission of Wolbachia would be enhanced by focusing infection in the reproductive tissues. In social insect hosts, this tropism would logically extend to reproductive rather than sterile castes, since the latter constitute a dead-end for vertically transmission. Here, we show that Wolbachia are not focused on reproductive tissues of eusocial insects, and that non-reproductive tissues of queens and workers of the ant Acromyrmex echinatior, harbour substantial infections. In particular, the comparatively high intensities of Wolbachia in the haemolymph, fat body, and faeces, suggest potential for horizontal transmission via parasitoids and the faecal-oral route, or a role for Wolbachia modulating the immune response of this host. It may be that somatic tissues and castes are not the evolutionary dead-end for Wolbachia that is commonly thought

    Multidisciplinary Investigations at P.O.W. Camp 198, Bridgend, S. Wales: Site of a Mass Escape in March 1945

    Get PDF
    The largest escape of German Prisoner of War (P.O.W.) in WW2 was in March 1945 from Camp 198, situated in Bridgend, South Wales, UK. Since camp closure the site has become derelict, and has not been scientifically investigated. This paper reports on the search to locate the P.O.W. escape tunnel that was dug from Hut 9. This hut remains in remarkable condition, with numerous P.O.W. graffiti still present. Also preserved is a prisoner-constructed false wall in a shower room behind which excavated material was hidden, though the tunnel entrance itself has been concreted over. Near-surface geophysics and ground-based LiDAR were used to locate the tunnel. Mid-frequency GPR surveys were judged optimal, with magnetometry least useful due to the above-ground metal objects. Archaeological excavations discovered the intact tunnel and bed-board shoring. With Allied P.O.W. escape camp attempts well documented, this investigation provides valuable insight into German escape efforts

    Comets, historical records and vedic literature

    Full text link
    A verse in book I of Rigveda mentions a cosmic tree with rope-like aerial roots held up in the sky. Such an imagery might have ensued from the appearance of a comet having `tree stem' like tail, with branched out portions resembling aerial roots. Interestingly enough, a comet referred to as `heavenly tree' was seen in 162 BC, as reported by old Chinese records. Because of weak surface gravity, cometary appendages may possibly assume strange shapes depending on factors like rotation, structure and composition of the comet as well as solar wind pattern. Varahamihira and Ballala Sena listed several comets having strange forms as reported originally by ancient seers such as Parashara, Vriddha Garga, Narada and Garga. Mahabharata speaks of a mortal king Nahusha who ruled the heavens when Indra, king of gods, went into hiding. Nahusha became luminous and egoistic after absorbing radiance from gods and seers. When he kicked Agastya (southern star Canopus), the latter cursed him to become a serpent and fall from the sky. We posit arguments to surmise that this Mahabharata lore is a mythical recounting of a cometary event wherein a comet crossed Ursa Major, moved southwards with an elongated tail in the direction of Canopus and eventually went out of sight. In order to check whether such a conjecture is feasible, a preliminary list of comets (that could have or did come close to Canopus) drawn from various historical records is presented and discussed.Comment: This work was presented in the International Conference on Oriental Astronomy held at IISER, Pune (India) during November, 201
    corecore