A prospective multiple case study of the impact of emerging scientific evidence on established colorectal cancer screening programs: a study protocol.

BackgroundHealth-policy decision making is a complex and dynamic process, for which strong evidentiary support is required. This includes scientifically produced research, as well as information that relates to the context in which the decision takes place. Unlike scientific evidence, this "contextual evidence" is highly variable and often includes information that is not scientifically produced, drawn from sources such as political judgement, program management experience and knowledge, or public values. As the policy decision-making process is variable and difficult to evaluate, it is often unclear how this heterogeneous evidence is identified and incorporated into "evidence-based policy" decisions. Population-based colorectal cancer screening poses an ideal context in which to examine these issues. In Canada, colorectal cancer screening programs have been established in several provinces over the past five years, based on the fecal occult blood test (FOBT) or the fecal immunochemical test. However, as these programs develop, new scientific evidence for screening continues to emerge. Recently published randomized controlled trials suggest that the use of flexible sigmoidoscopy for population-based screening may pose a greater reduction in mortality than the FOBT. This raises the important question of how policy makers will address this evidence, given that screening programs are being established or are already in place. This study will examine these issues prospectively and will focus on how policy makers monitor emerging scientific evidence and how both scientific and contextual evidence are identified and applied for decisions about health system improvement.MethodsThis study will employ a prospective multiple case study design, involving participants from Ontario, Alberta, Manitoba, Nova Scotia, and Quebec. In each province, data will be collected via document analysis and key informant interviews. Documents will include policy briefs, reports, meeting minutes, media releases, and correspondence. Interviews will be conducted in person with senior administrative leaders, government officials, screening experts, and high-level cancer system stakeholders.DiscussionThe proposed study comprises the third and final phase of an Emerging Team grant to address the challenges of health-policy decision making and colorectal cancer screening decisions in Canada. This study will contribute a unique prospective look at how policy makers address new, emerging scientific evidence in several different policy environments and at different stages of program planning and implementation. Findings will provide important insight into the various approaches that are or should be used to monitor emerging evidence, the relative importance of scientific versus contextual evidence for decision making, and the tools and processes that may be important to support challenging health-policy decisions

Chlorinated organic contaminants in breast milk of New Zealand women.

Breast milk samples from 38 women in New Zealand were analyzed for organochlorine pesticides, polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) as part of a World Health Organization collaborative study of breast-milk contaminants. The women were recruited from two urban areas (Auckland and Christchurch) and two rural areas (Northland and North Canterbury) in the North and South Islands of New Zealand. The best predictor of contaminant concentrations in breast milk was found to be the age of the mother. Regional differences were found for hexachlorobenzene, dieldrin, and pp-DDE, reflecting historical use patterns. Urban-rural differences were found for several PCBs, PCDDs, and PCDFs when contaminant concentrations were calculated on a whole-milk basis. However, these differences could be attributed to variation in breast-milk fat concentrations between urban and rural mothers. Urban mothers had about 50% more breast-milk fat than rural mothers. Evidence suggests that breast-milk consumption by babies is regulated by caloric intake. Almost all of the caloric content of milk is in the fat fraction. This suggests that breast-milk contaminant levels calculated on a whole-milk basis do not necessarily reflect the relative levels of exposure of infants to these contaminants. However, the factors that influence breast-milk fat concentration deserve further study

Crossing Symmetry Violation of Unitarized Pion-Pion Amplitude in the Resonance Region

Pion-pion scattering amplitude obtained from one-loop Chiral Perturbation Theory (ChPT) is crossing symmetric, however the corresponding partial wave amplitudes do not respect exact unitarity relation. There are different approaches to get unitarized partial wave amplitudes from ChPT. Here we consider the inverse amplitude method (IAM) that is often used to fit pion-pion phase shifts to experimental data, by adjusting free parameters. We measure the amount of crossing symmetry violation (CSV) in this case and we show that crossing symmetry is badly violated by the IAM unitarized ChPT amplitude in the resonance region. Important CSV also occurs when all free parameters are set equal to zero.Comment: 6 pages, 4 figure

Constraints on the Formation of the Planet Around HD188753A

The claimed discovery of a Jupiter-mass planet in the close triple star system HD 188753 poses a problem for planet formation theory. A circumstellar disk around the planet's parent star would be truncated close to the star, leaving little material available for planet formation. In this paper, we attempt to model a protoplanetary disk around HD 188753A using a fairly simple alpha-disk model, exploring a range of parameters constrained by observations of T Tauri-type stars. The disk is truncated to within 1.5 to 2.7 AU, depending on model parameters. We find that the in situ formation of the planet around HD 188753A is implausible.Comment: Accepted version, to appear in ApJ. 23 pages, 5 figures (3 in color

Establishing an evidenced-based dietetic model of care in haemodialysis using implementation science

To establish an evidence-based dietetics service in an in-centre haemodialysis unit utilising implementation science.The service was developed through the Knowledge-to-Action Framework. The steps of the Action Cycle were addressed through a literature review, identification of evidence-based guidelines, benchmarking and local staff engagement. The theoretical domains framework (TDF) was used to identify barriers/enablers, and behaviour change wheel to determine appropriate interventions. To monitor, evaluate outcomes and assess sustained knowledge use we employed multidisciplinary team engagement and database use. Audit data were collected at baseline, 6 and 12 months on nutrition assessment (Patient-Generated Subjective Global Assessment), intervention timeliness and alignment to dietetic workforce recommendations. Descriptive statistics, McNemar tests and a linear mixed model were applied.Barriers existed in the knowledge, skills, environmental context and resources TDF domains. Suitable interventions were identified with training on nutritional management of haemodialysis patients delivered to 148 nurses, and nutrition management recommendations summarised into local procedural resources. A database to prompt and monitor outcome measures was created and indicated that over 18 months post-service commencement, eligible patients received nutrition assessment at least 6-monthly, aligning with recommendations. Prevalence of malnutrition was 28% (n = 9/32) at baseline, 23% (n = 5/22) at 6 months and 20% (n = 4/20) at 12 months (P = 0.50).We demonstrated benefits to service development and implementation with implementation science providing a structured and methodical approach to translating guidelines into practice. Development of training, resources and prompts for outcome measures has supported the establishment of an evidence-based dietetics service in a haemodialysis unit

Modelling the ability of legumes to suppress weeds

The ability of different legume cover crops to suppress annual weeds during the early establishment phase was compared using a simulation model of inter-plant competition and field observations. Height, partitioning parameters, extinction coefficients, crop density and time of emergence were recorded for 11 species sown in monocultures. A naturally occurring population of fat hen (Chenopodium album) was present on the experiment. The competition model was run to compare the expected suppressive ability of the different species on this weed. Samples of C. album were also taken from each plot immediately prior to cutting to provide some empirical observations. Predicted suppressive ability was correlated with seed size and height with large seeded, tall species such as white sweet clover being the most competitive. However, these species may recover poorly from mowing compromising their potential to suppress perennial weeds and a mixture of contrasting species may provide the optimum weed control

A new method of observing weak extended x-ray sources with RHESSI

We present a new method, fan-beam modulation, for observing weak extended x-ray sources with the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI). This space-based solar x-ray and gamma-ray telescope has much greater sensitivity than previous experiments in the 3-25 keV range, but is normally not well suited to detecting extended sources since their signal is not modulated by RHESSI's rotating grids. When the spacecraft is offpointed from the target source, however, the fan-beam modulation time-modulates the transmission by shadowing resulting from exploiting the finite thickness of the grids. In this paper we detail how the technique is implemented and verify its consistency with sources with clear known signals that have occurred during RHESSI offpointing: microflares and the Crab Nebula. In both cases the results are consistent with previous and complementary measurements. Preliminary work indicates that this new technique allows RHESSI to observe the integrated hard x-ray spectrum of weak extended sources on the quiet Sun.Comment: Publishe