To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
The aim of this work is to report on the tumour control probability (TCP) of a UK cohort of lung stereotactic ablative radiotherapy patients (n = 198) for a range of dose and fractionations common in the UK.
Materials and methods:
TCP values for 3 (54 Gy), 5 (55 and 60 Gy) and 8 (50 Gy) fraction (#) schemes were calculated with the linear-quadratic Marsden TCP model using the Biosuite software.
TCP values of 100% were computed for the 3 # and for 5 # (α/β = 10 Gy) cohorts; reduced to 99% (range 97–100) for the 5 # cohort only when an α/β of 20 Gy was used. The average TCP value for the 50 Gy in 8 # regime was 97% (range 92–99, α/β = 10 Gy) and 64% (range 48–79, α/β = 20 Gy). Statistical significant differences were observed between the α/β of 10 Gy versus 20 Gy groups and between all data grouped by fraction.
TCPs achievable with current planning techniques in the UK have been presented. The ultra-conservative 50 Gy in 8 # scheme returns a significantly lower TCP than the other regimes.
Introduction: September 2017 saw the launch of the British Columbia (BC) Emergency Medicine Network (EM Network), an innovative clinical network established to improve emergency care across the province. The intent of the EM Network is to support the delivery of evidence-informed, patient-centered care in all 108 Emergency Departments and Diagnostic & Treatment Centres in BC. After one year, the Network undertook a formative evaluation to guide its growth. Our objective is to describe the evaluation approach and early findings. Methods: The EM Network was evaluated on three levels: member demographics, online engagement and member perceptions of value and progress. For member demographics and online engagement, data were captured from member registration information on the Network's website, Google Analytics and Twitter Analytics. Membership feedback was sought through an online survey using a social network analysis tool, PARTNER (Program to Analyze, Record, and Track Networks to Enhance Relationships), and semi-structured individual interviews. This framework was developed based on literature recommendations in collaboration with Network members, including patient representatives. Results: There are currently 622 EM Network members from an eligible denominator of approximately 1400 physicians (44%). Seventy-three percent of the Emergency Departments and Diagnostic and Treatment Centres in BC currently have Network members, and since launch, the EM Network website has been accessed by 11,154 unique IP addresses. Online discussion forum use is low but growing, and Twitter following is high. There are currently 550 Twitter followers and an average of 27 ‘mentions’ of the Network by Twitter users per month. Member feedback through the survey and individual interviews indicates that the Network is respected and credible, but many remain unaware of its purpose and offerings. Conclusion: Our findings underscore that early evaluation is useful to identify development needs, and for the Network this includes increasing awareness and online dialogue. However, our results must be interpreted cautiously in such a young Network, and thus, we intend to re-evaluate regularly. Specific action recommendations from this baseline evaluation include: increasing face-to-face visits of targeted communities; maintaining or accelerating communication strategies to increase engagement; and providing new techniques that encourage member contributions in order to grow and improve content.
Among the solar proxies, κ1 Cet, stands out as potentially having a mass very close to solar and a young age. We report magnetic field measurements and planetary habitability consequences around this star, a proxy of the young Sun when life arose on Earth. Magnetic strength was determined from spectropolarimetric observations and we reconstruct the large-scale surface magnetic field to derive the magnetic environment, stellar winds, and particle flux permeating the interplanetary medium around κ1 Cet. Our results show a closer magnetosphere and mass-loss rate 50 times larger than the current solar wind mass-loss rate when Life arose on Earth, resulting in a larger interaction via space weather disturbances between the stellar wind and a hypothetical young-Earth analogue, potentially affecting the habitability. Interaction of the wind from the young Sun with the planetary ancient magnetic field may have affected the young Earth and its life conditions.
Introduction: Atrial fibrillation and flutter (AFF) are the most common arrhythmias presenting to the emergency department. A coordinated ED AFF electronic order-set and management pathway was developed in collaboration with cardiologists at our institution. The primary objective of this study was to compare the ED length of stay pre and post pathway implementation. Secondary objectives included comparison of the following outcomes pre and post-pathway (PRE & POST): AFF Clinic referral rates, ED return rates, and mortality. Methods: This was a retrospective case series of patients presenting to our quarternary care ED with AFF pre and post AFF pathway implementation. Cases were identified using an administrative database covering 120 000 annual ED visits. Trained research assistants and the primary investigator extracted data from the electronic medical record. 20% of all charts were double collected to ensure accuracy (k=0.85). Descriptive variables were described using counts, means, medians and confidence intervals. Chi-square statistics of dependent samples were calculated for the primary outcome. Results: We examined 307 cases of AFF presenting to our ED (n=130 PRE; n=177 POST). Demographic variables were similar PRE and POST: mean age (66.0 [95%CI 63.8-68.3] PRE; 65.0 [63.0-67.0] POST), % male (59.2% PRE; 59.3% POST), presenting rhythm (66.2% A.fib [58.0-74.3] A. flutter 29.2% [21.4-37.0] PRE; 61.0% A.fib [53.8-68.1] A. flutter 17.5% [11.9-23.1] POST), and CHADS2VASC score (2.1 [1.8-2.4] PRE; 1.9 [1.7-2.1] POST). The mean ED LOS decreased by 72.5 minutes (95% CI -22.9 to -122.1; P < 0.001). AFF clinic referral rates increased from 16.9% PRE to 25.4% POST (not significant). ED return rates within 30 days for AFF, CHF, major bleeding and CVA were unchanged. 30 day mortality rates were not statistically different (1.5% PRE vs. 2.8% POST). Conclusion: A coordinated ED AFF pathway was associated with a significant reduction in ED LOS without significant changes in ED return rates or mortality.
Introduction: Vancouver Coastal Health (VCH) emergency physicians have been on contract based funding models for two decades. On October 1, 2015, physicians at one hospital (SPH) switched to fee-for-service (FFS) payments. Conventional wisdom is that FFS physicians are motivated to see more patients quickly and achieve higher throughput. Our hypothesis was that FFS payment would reduce patient wait times. Methods: This interrupted time series analysis with concurrent control was performed in VCH Region, where there are two tertiary EDs. During the 20-week study period (July 15-Nov 30), VGH remained on contract, while SPH converted to FFS (the intervention). VCH administrative data was aggregated by week. Our primary outcome was median wait time to MD. Secondary outcomes were ED LOS and left-without-being-seen (LWBS) rates. Results: Interrupted time series plots will be presented for the data. Data from 67,214 ED visits were analyzed (31,733 SPH, 35,481 VGH). Figure 1 shows that baseline wait time was 74 minutes at the control and 53 minutes at the intervention site. During the pre-intervention period, there was a non-significant downward trend of 0.4 minutes per week at the intervention hospital relative to control (p=0.26). After FFS conversion, there was a 4.1 minute increase in wait time at the control site (p=0.18), and a significant downward trend of 1.4 minutes per week (p=0.001). After FFS conversion, wait times at the intervention site increased by 4.8 minutes more than control (p-value for the difference=0.27), and the wait time trend increased significantly by 1.3 minutes per week relative to the expected counterfactual trend (p=0.02). Baseline EDLOS for discharged patients was 227 minutes at the control hospital and 193 minutes at the intervention site. There were similar pre-intervention LOS increases at both hospitals. Post-intervention, both sites saw significant increases in EDLOS, followed by a similar downward trends of -2.68 minutes per week (p=0.001). Baseline LWBS rate was 3.86% at the control hospital and 3.56% at the intervention site. Pre-intervention trends, and post-intervention level/trend changes did not differ by site. Conclusion: Conversion to FFS payment was associated with an increase in wait time trend of 1.3 minutes per week relative to control. There were no significant changes in EDLOS or LWBS rates. In this preliminary analysis, FFS payment had little effect on wait times or patient throughput.
Introduction: Atrial fibrillation and flutter (AFF) are the most common arrhythmias presenting to the emergency department. Without anticoagulation, AFF increases stroke risk; individuals with paroxysmal AFF have a similar prognosis. A coordinated ED AFF electronic order-set and management pathway was developed at our institution. The primary objective of this study was to measure rates of appropriate anticoagulation (AAC) on discharge from the ED for patients presenting with AFF not previously on antithrombotic or anticoagulant medications. Secondary objectives included comparison of the following outcomes pre and post-pathway (PRE & POST): AFF Clinic referral rates, ED return rates, and mortality. Methods: This was a retrospective case series of patients presenting to our quarternary care ED with AFF pre and post AFF pathway implementation. Cases were identified using an administrative database covering 120 000 annual ED visits. Trained research assistants and the primary investigator extracted data from the electronic medical record. 20% of all charts were double collected to ensure accuracy (k=0.85). Descriptive variables were described using counts, means, medians and confidence intervals. Chi-square statistics of dependent samples were calculated for the primary outcome. Results: We examined 307 cases of AFF presenting to our ED (n=130 PRE; n=177 POST). Demographic variables were similar PRE and POST: mean age (66.0 [95%CI 63.8-68.3] PRE; 65.0 [63.0-67.0] POST), % male (59.2% PRE; 59.3% POST), presenting rhythm (66.2% A.fib [58.0-74.3] A. flutter 29.2% [21.4-37.0] PRE; 61.0% A.fib [53.8-68.1] A. flutter 17.5% [11.9-23.1] POST), and CHADS2VASC score (2.1 [1.8-2.4] PRE; 1.9 [1.7-2.1] POST). The rate of AAC rose from 39.1% PRE to 77.8% POST (P < 0.01). AFF clinic referral rates increased from 16.9% PRE to 25.4% POST (not significant). ED return rates within 30 days for AFF, CHF, major bleeding and CVA were unchanged. 30 day mortality rates were not statistically different (1.5% PRE vs. 2.8% POST). Conclusion: The implementation of a coordinated ED AFF pathway was associated with significant improvements in the proportion of patients discharged with appropriate anticoagulation who had not previously been on antithrombotic or anticoagulant medications. ED return rates and mortality did not change significantly.
Current guidelines for image-guided cervical cancer brachytherapy planning recommend both computed tomography (CT) and magnetic resonance imaging (MRI) for adequate visualisation of the applicator and soft tissues, respectively. MRI-only planning would be ideal as it would save time within the patient pathway and avoid the concomitant CT exposures. However, applicator visualisation on MRI is usually achieved using fluid-filled fiducial marker tubes, which can be awkward to use and suffer from unwanted air bubble artefacts. Therefore, a new fiducial-free imaging technique was developed.
A dual echo time (TE) turbo spin echo sequence was used, at 1·5 T, to provide both T2-weighted images (100 ms TE) for tissue visualisation and strongly proton density-weighted images (17 ms TE) for improved applicator visualisation. In-house software was used to automatically segment the applicator in the short TE images (using Otsu's method) and transfer the information to the long TE images to provide a single fused dataset.
The method was evaluated successfully using titanium applicators in three patient cases and using a plastic applicator in a tissue-equivalent gel phantom.
The dual-echo technique provides a simple and efficient method for improving the visualisation of brachytherapy applicators in cervical cancer MRI images without the need for marker tubes.
κ1 Cet (HD 20630, HIP 15457, d = 9.16 pc, V = 4.84) is a dwarf star approximately 30 light-years away in the equatorial constellation of Cetus. Among the solar proxies studied in the Sun in Time, κ1 Cet stands out as potentially having a mass very close to solar and a young age. On this study, we monitored the magnetic field and the chromospheric activity from the Ca II H & K lines of κ1 Cet. We used the technique of Least-Square-Deconvolution (LSD, Donati et al. 1997) by simultaneously extracting the information contained in all 8,000 photospheric lines of the echelogram (for a linelist matching an atmospheric model of spectral type K1). To reconstruct a reliable magnetic map and characterize the surface differential rotation of κ1 Cet we used 14 exposures spread over 2 months, in order to cover at least two rotational cycles (Prot ~9.2 days). The Least Square deconvolution (LSD) technique was applied to detect the Zeeman signature of the magnetic field in each of our 14 observations and to measure its longitudinal component. In order to reconstruct the magnetic field geometry of κ1 Cet, we applied the Zeeman Doppler Imaging (ZDI) inversion method. ZDI revealed a structure in the radial magnetic field consisting of a polar magnetic spot. On this study, we present the fisrt look results of a high-resolution spectropolarimetric campaign to characterize the activity and the magnetic fields of this young solar proxy.
IAU Commission 6 “Astronomical Telegrams” had a single business meeting during the Beijing General Assembly of the IAU. It took place on Friday, August 24, 2012. The meeting was attended by five C6 members (N. N. Samus; D. W. E. Green; S. Nakano; J. Ticha; and H. Yamaoka). Also present was Prof. F. Genova as a representative of the IAU Division B. She told the audience about the current restructuring of IAU Commissions and Divisions and consequences for the future of C6.
In November 2009, we initiated a multistate investigation of Salmonella Montevideo infections with pulsed-field gel electrophoresis pattern JIXX01.0011. We identified 272 cases in 44 states with illness onset dates ranging from 1 July 2009 to 14 April 2010. To help generate hypotheses, warehouse store membership card information was collected to identify products consumed by cases. These records identified 19 ill persons who purchased company A salami products before onset of illness. A case-control study was conducted. Ready-to-eat salami consumption was significantly associated with illness (matched odds ratio 8·5, 95% confidence interval 2·1–75·9). The outbreak strain was isolated from company A salami products from an environmental sample from one manufacturing plant, and sealed containers of black and red pepper at the facility. This outbreak illustrates the importance of using membership card information to assist in identifying suspect vehicles, the potential for spices to contaminate ready-to-eat products, and preventing raw ingredient contamination of these products.
As earlier, the main activity of the Commission was performed by the Central Bureau for Astronomical Telegrams (CBAT), effectively directed by Dan Green. These three years were a difficult period for the Bureau and thus for the Commission because the Bureau unexpectedly had to move from the Smithsonian Astrophysical Observatory, its home since 1965, to the Harvard University's Department of Earth and Planetary Sciences. This move caused many serious administrative and logistical problems, effectively solved by the CBAT Director, Dan Green, and CBAT Director Emeritus, Brian Marsden. A great shock, not only for our commission but for the whole astronomical community, was Brian's death on November 18, 2010.
There is good evidence that forebrain serotonergic systems modulate cognitive flexibility. Latent inhibition (LI) is a cross-species phenomenon which manifests as poor conditioning to a stimulus that has previously been experienced without consequence and is widely considered an index of the ability to ignore irrelevant stimuli. While much research has focused on dopaminergic mechanisms underlying LI, there is also considerable evidence of serotonergic modulation. However, the neuroanatomical locus of these effects remains poorly understood. Previous work has identified the nucleus accumbens (NAc) as a key component of the neural circuit underpinning LI and furthermore, this work has shown that the core and shell subregions of the NAc contribute differentially to the expression of LI. To examine the role of the serotonergic input to NAc in LI, we tested animals with 5,7-dihydroxytryptamine (5,7-DHT) lesions to the core and shell subregions on LI assessed under experimental conditions that produce LI in shams and subsequently with weak stimulus pre-exposure designed to prevent the emergence of LI in shams. We found that serotonergic deafferentation of the core disrupted LI whereas 5,7-DHT lesions to the shell produced the opposite effect and potentiated LI.
The President verbally reported that the only scientific matter that he dealt with during the triennium as an appeal over the withholding of a supernova designation from an object observed only in the infra-red with no supporting spectrum.
The meeting was attended by 5 members of the WG (E. Bowell, G. Consolmagno, R. Courtain, R. Lopez, R. Schulz) one Task Group member (J. Watanabe), and several guests from the CSBN and CBAT. It was decided at the beginning of the meeting that the attending members of the WGPSN would discuss matters, provide their opinion or vote, and then ask the other 8 formal members to do the same via email. As a consequence the following discussed items have been agreed by majority vote of the WG members.
The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) has recently conducted an extragalactic submillimetric survey of the Chandra Deep Field South region of unprecedented size, depth, and angular resolution in three wavebands centered at 250,
350, and 500 µm. BLAST wavelengths are chosen to study the Cosmic Infrared Background near its peak at 200 µm.
We find that most of the CIB at these wavelengths is contributed by galaxies detected at 24 µm by the MIPS instrument on Spitzer, and that the source counts distribution shows a population with strongly evolving density and luminosity. These results anticipate what can be expected from the surveys that will be conducted with the SPIRE instrument on the Herschel space observatory.
Among the A/B stars, about 5% host large-scale organised magnetic fields. These magnetic stars show also abundance anomalies in their spectra, and are therefore called the magnetic Ap/Bp stars. Most of these stars are also slow rotators compared to the normal A and B stars.
Today, one of the greatest challenges concerning the Ap/Bp stars is to understand the origin of their slow rotation and their magnetic fields. The favoured hypothesis for the latter is that the fields are fosils, which implies that the magnetic fields subsist throughout the different evolutionary phases, and in particular during the pre-main sequence phase. The existence of magnetic fields at the pre-main sequence phase is also required to explain the slow rotation of Ap/Bp stars. During the last 3 years we performed a spectropolarimetric survey of the Herbig Ae/Be stars in the field and in young clusters, in order to investigate their magnetism and rotation. These investigations have resulted in the detection and/or confirmation of magnetic fields in 8 Herbig Ae/Be stars, ranging in mass from 2 to nearly 15 solar masses. In this paper I will present the results of our survey, as well as their implications for the origin and evolution of the magnetic fields and rotation of the A and B stars.
In many bird monitoring surveys, no attempt is made to estimate bird densities or abundance. Instead, counts of one form or another are made, and these are assumed to correlate with bird density. Unless complete counts on sample plots are feasible, this approach can easily lead to false conclusions, because detectability of birds varies by species, habitat, observer and many other factors. Trends in time of counts often reflect trends in detectability, rather than trends in abundance. Conclusions are further compromised when surveys are conducted at unrepresentative sites. We consider how to avoid these problems. We give a brief description of distance sampling methods, which allow detectability to be estimated. We consider strategies to ease their implementation, to enhance their reliability, to adapt the methods for difficult species, and to deal with circumstances in which representative sampling is problematic. We also consider some of the common problems encountered, and suggest solutions.
Colin Bibby (1948–2004) was the quintessential bird conservation biologist. Over his career, he served as lead scientist at two of the world's largest bird conservation organizations, the Royal Society for the Protection of Birds, and BirdLife International. His contributions encompassed detailed autecological studies of rare bird species such as the Dartford Warbler Sylvia undata (e.g. Bibby 1978) and Fuerteventura Stonechat Saxicola dacotiae (e.g. Bibby and Hill 1987), a sweeping synthesis of the techniques of bird conservation science (Bibby et al. 1992, 2000), and pioneering contributions in conservation planning such as the Endemic Bird Areas concept (ICBP 1992).
The purpose of this study is to analyse the transport and stirring of fluid that occurs owing to the formation and growth of a laminar vortex ring. Experimental data was collected upstream and downstream of the exit plane of a piston-cylinder apparatus by particle-image velocimetry. This data was used to compute Lagrangian coherent structures to demonstrate how fluid is advected during the transient process of vortex ring formation. Similar computations were performed from computational fluid dynamics (CFD) data, which showed qualitative agreement with the experimental results, although the CFD data provides better resolution in the boundary layer of the cylinder. A parametric study is performed to demonstrate how varying the piston-stroke length-to-diameter ratio affects fluid entrainment during formation. Additionally, we study how regions of fluid are stirred together during vortex formation to help establish a quantitative understanding of the role of vortical flows in mixing. We show that identification of the flow geometry during vortex formation can aid in the determination of efficient stirring. We compare this framework with a traditional stirring metric and show that the framework presented in this paper is better suited for understanding stirring/mixing in transient flow problems. A movie is available with the online version of the paper.
Derivative-free optimization techniques are applied in conjunction with large-eddy simulation (LES) to reduce the noise generated by turbulent flow over a hydrofoil trailing edge. A cost function proportional to the radiated acoustic power is derived based on the Ffowcs Williams and Hall solution to Lighthill's equation. Optimization is performed using the surrogate-management framework with filter-based constraints for lift and drag. To make the optimization more efficient, a novel method has been developed to incorporate Reynolds-averaged Navier–Stokes (RANS) calculations for constraint evaluation. Separation of the constraint and cost-function computations using this method results in fewer expensive LES computations. This work demonstrates the ability to fully couple optimization to large-eddy simulation for time-accurate turbulent flow. The results demonstrate an 89% reduction in noise power, which comes about primarily by the elimination of low-frequency vortex shedding. The higher-frequency broadband noise is reduced as well, by a subtle change in the lower surface near the trailing edge.