119 research outputs found
Five-brane Calibrations and Fuzzy Funnels
We present a generalisation of the Basu-Harvey equation that describes
membranes ending on intersecting five-brane configurations corresponding to
various calibrated geometries.Comment: 20 pages, latex, v2: typos fixed and refs adde
Harmonic Space, Self-Dual Yang Mills and the String
The geometrical structure and the quantum properties of the recently proposed
harmonic space action describing self-dual Yang-Mills (SDYM) theory are
analyzed. The geometrical structure that is revealed is closely related to the
twistor construction of instanton solutions. The theory gets no quantum
corrections and, despite having SDYM as its classical equation of motion, its S
matrix is trivial. It is therefore NOT the theory of the N=2 string. We also
discuss the 5-dimensional actions that have been proposed for SDYM.Comment: 23 Page
Defining success in bushfire management: critical moments in the 2012-13 ACT bushfire season
The 2012-13 Australian Capital Territory fire season saw no loss of life, no major property loss and minimal environmental damage. It was therefore successful according to the main aims of bushfire management. This outcome hinged on a few critical moments when, due to a combination of strategy and good fortune, things went right. This case study demonstrates how influential chance can be in determining the outcome of bushfires and this in turn begs the question: should agencies be held responsible for factors that are beyond human control? It is proposed that holding agencies responsible for outcomes that are not entirely within their control, acts to reduce community resilience because it implicitly removes the onus on individuals to take personal responsibility; a vital component for good outcomes
Liver resection surgery compared with thermal ablation in high surgical risk patients with colorectal liver metastases: the LAVA international RCT.
BACKGROUND: Although surgical resection has been considered the only curative option for colorectal liver metastases, thermal ablation has recently been suggested as an alternative curative treatment. There have been no adequately powered trials comparing surgery with thermal ablation. OBJECTIVES: Main objective - to compare the clinical effectiveness and cost-effectiveness of thermal ablation versus liver resection surgery in high surgical risk patients who would be eligible for liver resection. Pilot study objectives - to assess the feasibility of recruitment (through qualitative study), to assess the quality of ablations and liver resection surgery to determine acceptable standards for the main trial and to centrally review the reporting of computed tomography scan findings relating to ablation and outcomes and recurrence rate in both arms. DESIGN: A prospective, international (UK and the Netherlands), multicentre, open, pragmatic, parallel-group, randomised controlled non-inferiority trial with a 1-year internal pilot study. SETTING: Tertiary liver, pancreatic and gallbladder (hepatopancreatobiliary) centres in the UK and the Netherlands. PARTICIPANTS: Adults with a specialist multidisciplinary team diagnosis of colorectal liver metastases who are at high surgical risk because of their age, comorbidities or tumour burden and who would be suitable for liver resection or thermal ablation. INTERVENTIONS: Thermal ablation conducted as per local policy (but centres were encouraged to recruit within Cardiovascular and Interventional Radiological Society of Europe guidelines) versus surgical liver resection performed as per centre protocol. MAIN OUTCOME MEASURES: Pilot study - patients' and clinicians' acceptability of the trial to assist in optimisation of recruitment. Primary outcome - disease-free survival at 2 years post randomisation. Secondary outcomes - overall survival, timing and site of recurrence, additional therapy after treatment failure, quality of life, complications, length of hospital stay, costs, trial acceptability, and disease-free survival measured from end of intervention. It was planned that 5-year survival data would be documented through record linkage. Randomisation was performed by minimisation incorporating a random element, and this was a non-blinded study. RESULTS: In the pilot study over 1 year, a total of 366 patients with colorectal liver metastases were screened and 59 were considered eligible. Only nine participants were randomised. The trial was stopped early and none of the planned statistical analyses was performed. The key issues inhibiting recruitment included fewer than anticipated patients eligible for both treatments, misconceptions about the eligibility criteria for the trial, surgeons' preference for one of the treatments ('lack of clinical equipoise' among some of the surgeons in the centre) with unconscious bias towards surgery, patients' preference for one of the treatments, and lack of dedicated research nurses for the trial. CONCLUSIONS: Recruitment feasibility was not demonstrated during the pilot stage of the trial; therefore, the trial closed early. In future, comparisons involving two very different treatments may benefit from an initial feasibility study or a longer period of internal pilot study to resolve these difficulties. Sufficient time should be allowed to set up arrangements through National Institute for Health Research (NIHR) Research Networks. TRIAL REGISTRATION: Current Controlled Trials ISRCTN52040363. FUNDING: This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 21. See the NIHR Journals Library website for further project information
Mechanistic modeling of twin screw wet granulation for pharmaceutical formulations : calibration, sensitivity analysis, and model-driven workflow
Wet granulation, a particle size enlargement process, can significantly enhance the critical quality attributes of powders and improve the ability to form tablets in pharmaceutical manufacturing. In this study, a mechanistic-based population balance model is applied to twin screw wet granulation. This model incorporated a recently developed breakage kernel specifically designed for twin screw granulation, along with nucleation, layering, and consolidation. Calibration and validation were performed on Hydrochlorothiazide and Acetaminophen formulations, which exhibit different particle size and wettability characteristics. Utilizing a compartmental experimental dataset, a comprehensive global sensitivity analysis identified critical inputs impacting quality attributes. The study revealed that the nucleation rate process model, effectively represented particle size distributions for both formulations. Adjustments to nucleation and breakage rate parameters, influenced by material properties and screw configuration, improved the model's accuracy. A model-driven workflow was proposed, offering step-by-step guidelines and facilitating PBM model usage, providing essential details for future active pharmaceutical ingredient (API) formulations
Professionalism, Golf Coaching and a Master of Science Degree: A commentary
As a point of reference I congratulate Simon Jenkins on tackling the issue of professionalism in coaching. As he points out coaching is not a profession, but this does not mean that coaching would not benefit from going through a professionalization process. As things stand I find that the stimulus article unpacks some critically important issues of professionalism, broadly within the context of golf coaching. However, I am not sure enough is made of understanding what professional (golf) coaching actually is nor how the development of a professional golf coach can be facilitated by a Master of Science Degree (M.Sc.). I will focus my commentary on these two issues
Moon Zoo: citizen science in lunar exploration
The Moon Zoo Team describe how citizen scientists can get involved and explore the Moon online
The relationship between clinical and recovery dimensions of outcome in mental health
Background: Little is known about the empirical relationship between clinical and personal recovery.
Aims: To examine whether there are separate constructs of clinical recovery and personal recovery dimensions of outcome, how they change over time and how they can be assessed.
Method: Standardised outcome measures were administered at baseline and one-year follow-up to participants in the REFOCUS Trial (ISRCTN02507940). An exploratory factor analysis was conducted and a confirmatory factor analysis assessed change across time.
Results: We identified three factors: patient-rated personal recovery, patient-rated clinical recovery and staff-rated clinical recovery. Only the personal recovery factor improved after one year. HHI, CANSAS-P and HoNOS were the best measures for research and practice.
Conclusions: The identification of three rather than two factors was unexpected. Our findings support the value of concurrently assessing staff and patient perceptions of outcome. Only the personal recovery factor changed over time, this desynchrony between clinical and recovery outcomes providing empirical evidence that clinical recovery and personal recovery are not the same. We did not find evidence of a trade-off between clinical recovery and personal recovery outcomes. Optimal assessment based on our data would involve assessment of hope, social disability and patient-rated unmet need
High hospital research participation and improved colorectal cancer survival outcomes: a population-based study
Objective: In 2001, the National Institute for Health Research (NIHR) Cancer Research Network (NCRN) was established, leading to a rapid increase in clinical research activity across the English NHS. Using colorectal cancer (CRC) as an example, we test the hypothesis that high, sustained hospital-level participation in interventional clinical trials improves outcomes for all CRC patients managed in those research-intensive hospitals.
Design: Data for patients diagnosed with CRC in England in 2001-2008 (n=209,968) were linked with data on accrual to NCRN CRC studies (n=30,998). Hospital Trusts were categorised by the proportion of patients accrued to interventional studies annually. Multivariable models investigated the relationship between 30-day post-operative mortality and five-year survival and the level and duration of study participation.
Results: Most of the Trusts achieving high participation were district general hospitals and the effects were not limited to cancer âcentres of excellenceâ, although such centres do make substantial contributions. Patients treated in Trusts with high research participation (â„16%) in their year of diagnosis had lower post-operative mortality (p<0.001) and improved survival (p<0.001) after adjustment for casemix and hospital-level variables. The effects increased with sustained research participation, with a reduction in post-operative mortality of 1.5% (6.5% to 5%, p<2.2*10-6) and an improvement in survival (p<10 19; 5-year difference: 3.8% (41.0% to 44.8%)) comparing high participation for â„4 years with 0 years.
Conclusion: There is a strong independent association between survival and participation in interventional clinical studies for all CRC patients treated in the hospital, not only study participants. Improvement precedes and increases with the level and years of sustained participation
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