Learning from failure

We study decentralized learning in organizations. Decentralization is captured through a symmetry constraint on agents’ strategies. Among such attainable strategies, we solve for optimal and equilibrium strategies. We model the organization as a repeated game with imperfectly observable actions. A fixed but unknown subset of action profiles are successes and all other action profiles are failures. The game is played until either there is a success or the time horizon is reached. For any time horizon, including infinity, we demonstrate existence of optimal attainable strategies and show that they are Nash equilibria. For some time horizons, we can solve explicitly for the optimal attainable strategies and show uniqueness. The solution connects the learning behavior of agents to the fundamentals that characterize the organization: Agents in the organization respond more slowly to failure as the future becomes more important, the size of the organization increases and the probability of success decreases.Game theory

How are teeth better than bone? An investigation of dental tissue diagenesis and state of preservation at a histological scale (with photo catalogue)

Teeth are often the preferred substrate for isotopic and genetic assays in archaeological research. Teeth can yield isotopic signals from different periods of an individual's lifetime, useful in dietary reconstruction, climate research, and investigation into mobility of people and animals in the past. Additionally, it is generally accepted that teeth preserve biomolecules (e.g. DNA, collagen) and isotopic signals better. Despite the importance of dental tissue in archaeological research, no systematic study has been carried out concerning diagenetic alterations at histological scale. This article reports the results of a thorough histological characterisation of post-mortem alterations observed in 34 ancient teeth. Such alterations are well described in bone whereas similar analyses of teeth are scant and highlight the need for diagenetic screening before analysis. Micrographs have been made, illustrating typical diagenetic features occurring within the dental tissues cementum, dentine and enamel including bioerosion, cracking, etching and staining. The photo catalogue produced can be used within fields such as archaeology, forensics and palaeontology

Kinderen met constitutioneel eczeem: de gevolgen voor ouders.

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Why Medical Residents Do (and Don’t) Speak Up About Organizational Barriers and Opportunities to Improve the Quality of Care

Purpose Medical residents are valuable sources of information about the quality of frontline service delivery, but if they do not speak up, their ideas, opinions, and suggestions for improving their work practices cannot be considered. However, speaking up can be difficult for residents. Therefore, the authors have explored both what helps residents speak up about organizational barriers and opportunities to improve the quality of their work and what hinders them from doing so. Method The authors conducted an exploratory qualitative interview study with 27 Dutch medical residents in the Netherlands in 2016. They used the critical incident technique for data collection and the constant comparison method of the Qualitative Analysis Guide of Leuven for data analysis. Results Three types of incidents in which residents considered speaking up are described. The authors identified 2 main considerations that influenced residents’ decisions about speaking up: Is it safe to speak up, and is speaking up likely to be effective? Residents’ decisions were influenced by personal, team, and organizational aspects of their situations, such as supervisors’ open attitudes, hierarchy, duration of clinical rotations, organization size, and experiences (either vicarious or their own). Conclusions Findings from this study indicate that residents tend to be silent when they encounter organizational barriers or opportunities to improve the quality of their work. Perceived effectiveness and safety are important forces that drive and constrain speaking up. The authors provide important starting points to empower medical residents to speak up about their suggestions for change

17 alpha-hydroxyprogesterone caproate for the prevention of adverse neonatal outcome in multiple pregnancies

OBJECTIVE: To estimate whether administration of 17 alpha-hydroxyprogesterone caproate can prevent neonatal morbidity in multiple pregnancies by reducing the preterm birth rate. METHODS: We conducted a multicenter, double-blind, placebo-controlled randomized trial in 55 obstetric clinics in the Netherlands. Women with a multiple pregnancy were randomized to weekly injections of either 250 mg 17 alpha-hydroxyprogesterone caproate or placebo, starting between 16 and 20 weeks of gestation and continuing until 36 weeks of gestation. The main outcome measure was adverse neonatal outcome. Secondary outcome measures were gestational age at delivery and delivery before 28, 32, and 37 weeks of gestation. RESULTS: We randomized 671 women. A composite measure of adverse neonatal outcome was present in 110 children (16%) born to mothers in the 17 alpha-hydroxyprogesterone caproate group, and in 80 children (12%) of mothers in the placebo group (relative risk [RR] 1.34; 95% confidence interval [CI] 0.95-1.89). The mean gestational age at delivery was 35.4 weeks for the 17 alpha-hydroxyprogesterone caproate group and 35.7 weeks for the placebo group (P =.32). Treatment with 17 alpha-hydroxyprogesterone caproate did not reduce the delivery rate before 28 weeks (6% in the 17 alpha-hydroxyprogesterone caproate group compared with 5% in the placebo group, RR 1.04; 95% CI 0.56-1.94), 32 weeks (14% compared with 10%, RR 1.37; 95% CI 0.91-2.05), or 37 weeks of gestation (55% compared with 50%, RR 1.11; 95% CI 0.97-1.28). CONCLUSION: 17 alpha-hydroxyprogesterone caproate does not prevent neonatal morbidity or preterm birth in multiple pregnancies

Hypometabolism of the posterior cingulate cortex is not restricted to Alzheimer's disease

When differential diagnosis of dementia includes both Alzheimer's disease (AD) and the behavioural variant of frontotemporal dementia (bvFTD), distribution of cerebral glucose metabolism as measured using [18F]‑2‑fluoro‑2‑deoxy‑D‑glucose positron emission tomography ([18F]FDG-PET) may be helpful. One important clue for differentiation is the presence of hypometabolism in the posterior cingulate cortex (PCC), usually associated with AD. PCC hypometabolism however, could also be present in bvFTD. Therefore, the specificity of PCC hypometabolism was examined. Based on visual reading PCC hypometabolism was present in 69–73/81 probable AD patients, in 10–16/33 probable bvFTD patients, and in 0–1/22 cognitive normal (CN) subjects. Findings were validated using a PCC to reference tissue [18F]FDG standard uptake value ratio (SUVr) cut-off, which was derived from the receiver operating characteristic (ROC) separating probable AD from CN, resulting in 9–14/33 bvFTD patients having PCC hypometabolism, depending on the reference tissue used. In conclusion, PCC hypometabolism is not restricted to AD