An efficient strategy for evaluating new non-invasive screening tests for colorectal cancer: the guiding principles.

New screening tests for colorectal cancer (CRC) are rapidly emerging. Conducting trials with mortality reduction as the end point supporting their adoption is challenging. We re-examined the principles underlying evaluation of new non-invasive tests in view of technological developments and identification of new biomarkers. A formal consensus approach involving a multidisciplinary expert panel revised eight previously established principles. Twelve newly stated principles emerged. Effectiveness of a new test can be evaluated by comparison with a proven comparator non-invasive test. The faecal immunochemical test is now considered the appropriate comparator, while colonoscopy remains the diagnostic standard. For a new test to be able to meet differing screening goals and regulatory requirements, flexibility to adjust its positivity threshold is desirable. A rigorous and efficient four-phased approach is proposed, commencing with small studies assessing the test's ability to discriminate between CRC and non-cancer states (phase I), followed by prospective estimation of accuracy across the continuum of neoplastic lesions in neoplasia-enriched populations (phase II). If these show promise, a provisional test positivity threshold is set before evaluation in typical screening populations. Phase III prospective studies determine single round intention-to-screen programme outcomes and confirm the test positivity threshold. Phase IV studies involve evaluation over repeated screening rounds with monitoring for missed lesions. Phases III and IV findings will provide the real-world data required to model test impact on CRC mortality and incidence. New non-invasive tests can be efficiently evaluated by a rigorous phased comparative approach, generating data from unbiased populations that inform predictions of their health impact

The ecogenetic link between demography and evolution : can we bridge the gap between theory and data?

Calls to understand the links between ecology and evolution have been common for decades. Population dynamics, i.e. the demographic changes in populations, arise from life history decisions of individuals and thus are a product of selection, and selection, on the contrary, can be modified by such dynamical properties of the population as density and stability. It follows that generating predictions and testing them correctly requires considering this ecogenetic feedback loop whenever traits have demographic consequences, mediated via density dependence (or frequency dependence). This is not an easy challenge, and arguably theory has advanced at a greater pace than empirical research. However, theory would benefit from more interaction between related fields, as is evident in the many near-synonymous names that the ecogenetic loop has attracted. We also list encouraging examples where empiricists have shown feasible ways of addressing the question, ranging from advanced data analysis to experiments and comparative analyses of phylogenetic data

Efeito da classificação dos ovos sobre o rendimento de incubação e os pesos do pinto e do saco vitelino Effect of egg classification prior to setting on hatchability, embryonic mortality and chick and yolk sac weights

Dois experimentos foram realizados para avaliar, no primeiro, o efeito da idade da matriz sobre a uniformidade do peso de 1080 ovos e gemas e, no segundo, a influência da classificação de 9260 ovos sobre a eclodibilidade, a mortalidade embrionária e os pesos, absoluto e relativo, do pinto e do saco vitelino. Os tratamentos do experimento I foram ovos das matrizes com 31 (M31), 38 (M38) e 43 (M43) semanas de idade. No segundo, os ovos das matrizes com 31, 38 e 43 semanas foram distribuídos em seis tratamentos; A: ovos com pesos entre 66 e 72g, 33,3% deles originados de matrizes com diferentes idades; B: ovos com pesos entre 58 e 65g, 33,3% deles originados de matrizes com diferentes idades; C: ovos com pesos entre 52 e 57g, 33,3% deles originados de matrizes com diferentes idades; D: ovos com pesos entre 52 e 72g, produzidos por matrizes com 31 semanas; E: ovos com pesos entre 52 e 72g, produzidos por matrizes com 38 semanas; e F: ovos com pesos entre 52 e 72g, produzidos por matrizes com 43 semanas. As aves de M31 produziram ovos com pesos do ovo e da gema mais uniformes que as do M43. Ovos do tratamento A apresentaram a pior eclosão e a maior mortalidade embrionária após 15 dias de incubação, e produziram pintos com maiores pesos absoluto e relativo do saco vitelino.<br>Two experiments were carried out to study the effects of broiler breeder age on weight uniformity of 1,080 eggs and yolks, and the effects of 9,216 eggs classified prior to setting on hatchability, embryonic mortality, and the relationship between chick and yolk sac weights. In the first study, the three treatments were eggs from broiler breeders on 31st (M31), 38th (M38), and 43th (M43)-week of age. In the second study, eggs produced by three broiler breeders flocks (31st, 38th, and 43th wk of age) were divided in six treatments; A: eggs weighting from 66 to 72g, 33,3% of them produced by broiler breeders of different ages; B: eggs weighting from 58 to 65g, 33,3% of them produced by broiler breeders of different ages; C: eggs weighting from 52 to 57g, 33,3% of them produced by broiler breeders of different ages; D: eggs from 31-wk-old broiler breeders, weighting from 52 to 72g; E: eggs from 38-wk-old broiler breeders, weighting from 52 to 72g; F: eggs from 43-wk- old broiler breeders weighting from 52 to 72g. Eggs produced by M31 had egg and yolk weights more uniform than the eggs collected from M43. Treatment A had the worst hatchability, higher embryonic mortality after 15 days of incubation, and produced heavier hatched chicks with superior absolute and relative weights of yolk sac