2,489 research outputs found
Self-expanding metal stent placement for oesophageal cancer without fluoroscopy is safe and effective
Background. Self-expanding metal stents (SEMS) are widely used to palliate patients with oesophageal cancer. Placement is usually done under endoscopic and fluoroscopic guidance. We have developed an exclusively endoscopic technique to deploy these stents. This article documents the technique and periprocedural experience.Patients and methods. All patients who had SEMS placement for oesophageal cancer at Grey’s Hospital, Pietermaritzburg, South Africa, over a 5-year period (2007 - 2011) were reviewed. Stenting was performed without radiological guidance using the technique documented in this article. At endoscopy, the oesophageal lesion was identified, dilated over a guidewire if necessary, and a partially covered stent was passed over the wire and positioned and deployed under direct vision. Data were captured from completed procedure forms and included demographics, tumour length, the presence of fistulas, stent size and immediate complications.Results. A total of 480 SEMS were inserted, involving 453 patients, of whom 43 required repeat stenting. There were 185 female patients (40.8%) and 268 male patients (59.2%). The mean age was 60 years (range 38 - 101). There were 432 black patients (95.4%), 15 white patients (3.3%) and 6 Indian patients (1.3%). The reasons for palliative stenting were distributed as follows: age >70 years n=95 patients, tumour >8 cm n=142, tracheo-oesophageal fistula (TOF) n=29, and unspecified n=170. One patient refused surgery, and one stent was placed for a post-oesophagectomy leak. Repeat stenting was for stent migration (n=15), tumour overgrowth (n=26) and a blocked stent and a stricture (n=1 each). Complications were recorded in six cases (1.3%): iatrogenic TOF (n=2), false tracts (n=3) and perforation (n=1). All six were nevertheless successfully stented. There was no periprocedural mortality.Conclusion. The endoscopic placement technique described is a viable and safe option with a low periprocedural complication rate. It is of particular use in situations of restricted access to fluoroscopic guidance
Standardising terminology and notation for the analysis of demographic processes in marked populations
The development of statistical methods for the analysis of demographic processes in marked animal populations has brought with it the challenges of communication between the disciplines of statistics, ecology, evolutionary biology and computer science. In order to aid communication and comprehension, we sought to root out a number of cases of ambiguity, redundancy and inaccuracy in notation and terminology that have developed in the literature. We invited all working in this field to submit topics for resolution and to express their own views. In the ensuing discussion forum it was then possible to establish a series of general principles which were, almost without exception, unanimously accepted. Here we set out the background to the areas of confusion, how these were debated and the conclusions which were reached in each case. We hope that the resulting guidelines will be widely adopted as standard terminology in publications and in software for the analysis of demographic processes in marked animal populationspostprin
Time-varying covariates and semi-parametric regression in capture-recapture: an adaptive spline approach
Advances in capture–recapture methodology have allowed the inclusion of continuous, time-dependent individual-covariates as predictors of survival and capture probabilities. The problem posed by these covariates is that they are only observed for an individual when that individual is captured. One solution is to assume a model of the covariate which defines the distribution of unobserved values,
conditional on the observed values, and apply Bayesian methods to compute parameter estimates and to test the covariate’s effect.
Previous applications of this approach have modeled the survival probability as a linear function of the covariate on some scale (e.g. identity or logistic). In some applications a linear function may not adequately describe the true relationship. Here we incorporate semi-parametric regression to allow for more flexibility in the relationship between the covariate and the survival probabilities of the Cormack–
Jolly–Seber model. A fully Bayesian, adaptive algorithm is used to model the relationship with splines, in which the complexity of the relationship is governed by the number and location of the knots in the spline. A reversible jump Markov chain Monte Carlo algorithm is implemented to explore splines with different knot configurations, and model averaging is used to compute the final estimates of the survival
probabilities.
The method is applied to a simulated data set and to data collected through the Dutch Constant Effort Sites ringing project to study the survival of reed warblers (Acrocephalus scirpaceus) as a function of condition.postprin
The importance of changing climatic variability for tropical wildlife population growth rates
Oral Session: Global change biologyMuch interest in the population impact of climate change has focused on the widespread increases in mean temperature, but little attention has been paid to the less homogeneous and less predictable changes in temperature variability. Well-established demographic theories have long pointed to a potential impact of environmental variability on population growth rates, but these have rarely been tested in practice, and the limited evidence available has suggested only minor effects. Using long-term data on tropical bird populations, we demonstrate that the prevailing levels of temperature variability are large enough to have a major impact; reducing population growth rates by up to half ...postprin
General practitioners’ perspectives on campaigns to promote rapid help-seeking behaviour at the onset of rheumatoid arthritis
Objective. To explore general practitioners’ (GPs’ ) perspectives on public health campaigns to encourage people with the early symptoms of rheumatoid arthritis (RA) to seek medical help rapidly. Design. Nineteen GPs participated in four semistructured focus groups. Focus groups were audio-recorded, transcribed verbatim, and analysed using thematic analysis. Results. GPs recognised the need for the early treatment of RA and identified that facilitating appropriate access to care was important. However, not all held the view that a delay in help seeking was a clinically significant issue. Furthermore, many were concerned that the early symptoms of RA were often non-specific, and that current knowledge about the nature of symptoms at disease onset was inadequate to inform the content of a help-seeking campaign. They argued that a campaign might not be able to specifically target those who need to present urgently. Poorly designed campaigns were suggested to have a negative impact on GPs’ workloads, and would “clog up” the referral pathway for genuine cases of RA. Conclusions. GPs were supportive of strategies to improve access to Rheumatological care and increase public awareness of RA symptoms. However, they have identified important issues that need to be considered in developing a public health campaign that forms part of an overall strategy to reduce time to treatment for patients with new onset RA. This study highlights the value of gaining GPs’ perspectives before launching health promotion campaigns
Do Interventions Designed to Support Shared Decision-Making Reduce Health Inequalities? : A Systematic Review and Meta-Analysis
Copyright: © 2014 Durand et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Background: Increasing patient engagement in healthcare has become a health policy priority. However, there has been concern that promoting supported shared decision-making could increase health inequalities. Objective: To evaluate the impact of SDM interventions on disadvantaged groups and health inequalities. Design: Systematic review and meta-analysis of randomised controlled trials and observational studies.Peer reviewe
The effects of an area-based intervention on the uptake of maternal and child health assessments in Australia: A community trial
Background
Recognition of the importance of the early years in determining health and educational attainment and promotion of the World Health Organization Health for All (HFA) principles has led to an international trend towards community-based initiatives to improve developmental outcomes among socio-economically disadvantaged children. In this study we examine whether, Best Start, an Australian area-based initiative to improve child health was effective in improving access to Maternal and Child Health (MCH) services.
Methods
The study compares access to information, parental confidence and annual 3.5 year Ages and Stages visiting rates before (2001/02) and after (2004/05) the introduction of Best Start. Access to information and parental confidence were measured in surveys of parents with 3 year old children. There were 1666 surveys in the first wave and 1838 surveys in the second wave. The analysis of visiting rates for the 3.5 year Ages and Stages visit included all eligible Victorian children. Best Start sites included 1,739 eligible children in 2001/02 and 1437 eligible children in 2004/05. The comparable figures in the rest of the state were and 45, 497 and 45, 953 respectively.
Results
There was a significant increase in attendance at the 3.5 year Ages and Stages visit in 2004/05 compared to 2001/02 in all areas. However the increase in attendance was significantly greater at Best Start sites than the rest of the state. Access to information and parental confidence improved over the course of the intervention in Best Start sites with MCH projects compared to other Best Start sites.
Conclusion
These results suggest that community-based initiatives in disadvantaged areas may improve parents' access to child health information, improve their confidence and increase MCH service use. These outcomes suggest such programmes could potentially contribute to strategies to reduce child health inequalities
Slepian functions and their use in signal estimation and spectral analysis
It is a well-known fact that mathematical functions that are timelimited (or
spacelimited) cannot be simultaneously bandlimited (in frequency). Yet the
finite precision of measurement and computation unavoidably bandlimits our
observation and modeling scientific data, and we often only have access to, or
are only interested in, a study area that is temporally or spatially bounded.
In the geosciences we may be interested in spectrally modeling a time series
defined only on a certain interval, or we may want to characterize a specific
geographical area observed using an effectively bandlimited measurement device.
It is clear that analyzing and representing scientific data of this kind will
be facilitated if a basis of functions can be found that are "spatiospectrally"
concentrated, i.e. "localized" in both domains at the same time. Here, we give
a theoretical overview of one particular approach to this "concentration"
problem, as originally proposed for time series by Slepian and coworkers, in
the 1960s. We show how this framework leads to practical algorithms and
statistically performant methods for the analysis of signals and their power
spectra in one and two dimensions, and on the surface of a sphere.Comment: Submitted to the Handbook of Geomathematics, edited by Willi Freeden,
Zuhair M. Nashed and Thomas Sonar, and to be published by Springer Verla
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