A secure additive protocol for card players

Consider three players Alice, Bob and Cath who hold a, b and c cards, respectively, from a deck of d=a+b+c cards. The cards are all different and players only know their own cards. Suppose Alice and Bob wish to communicate their cards to each other without Cath learning whether Alice or Bob holds a specific card. Considering the cards as consecutive natural numbers 0,1,..., we investigate general conditions for when Alice or Bob can safely announce the sum of the cards they hold modulo an appropriately chosen integer. We demonstrate that this holds whenever a,b>2 and c=1. Because Cath holds a single card, this also implies that Alice and Bob will learn the card deal from the other player's announcement

Ecosystem modelling of tropical wetlands

4.1 Background Modelling is essential for enhancing our understanding of the functioning of tropical wetland ecosystems, and for simulating future trajectories and testing for system thresholds. Anthropogenic activities such as drainage and land-use change can be integrated in models and their impacts on fluxes of greenhouse gas concentrations simulated. Models can also be used to test the response of peatlands and mangroves to climate extremes, variability and change, and to estimate reference levels and greenhouse gas emissions scenarios in the framework of climate change mitigation projects such as REDD+. In coastal settings, models are used to explore wetland resilience to sea-level rise. Finally, models can also be developed to support the decision making process by providing policyrelevant information on the consequences and trade-offs of adopting different management and climate scenarios

Micromorphological indicators for degradation processes in archaeological bone from temperate European wetland sites

Micromorphological investigations of archaeological bones make it possible to study decay processes and the associated depositional environment in one go. A selection of micromorphological thin sections from soil samples from three wetland sites in Switzerland, The Netherlands and Norway that contained bone fragments were studied. The goal was to investigate the type and the timing of decay processes to better understand the taphonomy of bones in such sites. Using optical microscopy and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), a range of biological decay processes and chemical/mineralogical transformations were observed. In two of the sites e Zug-Riedmatt in Switzerland and Hazendonk in The Netherlands e a relatively short exposure to adverse conditions must have occurred: Some of the bones from Zug-Riedmatt show localized collagen decay related to exposure to fresh ashes; others show cyanobacterial tunnelling related to submersion in shallow, clear water. In Hazendonk, bone fragments and fish scales apparently have first been exposed to bacterial decay related to putrefaction. Subsequently, alternations between wet and dry conditions resulted in the dissolution of some of the bone mineral and the formation of Ca, Fe(III) phosphates, probably mitridatite. Fungal decay caused extensive tunnelling of bone and fish scales as well as the secondary phosphates. These processes apparently ended when the bone-rich layer became permanently waterlogged and anoxic. In Stavanger, bone mineral is transformed into mitridatite and possibly other Ca Fe(III) phosphates. Indications that the redox conditions are variable at present suggest that these processes are still active. ©submittedVersio

Validation of game scenarios for the assessment of professional competence: Development of a serious game for system managers in training

Serious games hold potential for fostering the acquisition of more complex problem solving skills in professional practice. However, until now the empirical evidence on these workplace learning effects of serious games has remained rather scarce. Therefore such games have hardly been adopted for assessment purposes. This article argues why a validation method is needed that points out and controls what and where learners are learning from games. The core of the method entails mapping the learning activities on the performance indicators and outputs, as derived from the formal attainment levels in vocational education. In this study we have elaborated and applied a validation method for the development of a scenario-based assessment game for system managers in (secondary vocational) education. The method provides a general procedure, practical guidelines, and assessment forms, that can be used beyond this educational context and domain by those interested in more dynamic and motivating ways to assess the acquisition of complex skills in workplace learning

Association between nutritional status and subjective health status in chronically ill children attending special schools

Purpose: In hospitalized children with a chronic disease, malnutrition was associated with a lower subjective health status. In outpatient children with a chronic disease attending special schools, this association has never been studied. The aim of this study was to assess the association between nutritional status and subjective health status in chronically ill children attending special schools. Methods: Overall, 642 children, median age 9.8 years (IQR 7.7–11.5), 60 % male, 72 % Caucasian, were included in this prospective study in nine special schools for chronically ill children in the Netherlands. Overall malnutrition was assessed as: acute malnutrition (<−2 SDS for weight for height (WFH)) and chronic malnutrition (<−2 SDS for height for age). The malnutrition risk was assessed with the nutritional risk-screening tool STRONGkids. Subjective health status was assessed with EQ-5D. Results: Overall, 16 % of the children had overall malnutrition: 3 % acute and 13 % chronic malnutrition. Nurses reported ‘some/severe problems’ on the health status dimensions mobility (15 %), self-care (17 %), usual activities (19 %), pain/discomfort (22 %), and anxiety/depression (22 %) in chronically ill children. Their mean visual analogue scale score (VAS) was 73.0 (SD 11.1). Malnutrition, medication usage, and younger age explained 38 % of the variance of the VAS score. Conclusions: The presence of overall malnutrition in chronically ill children attending special schools was associated with lower subjective health status, especially in younger children and in those with chronic medication usage. Therefore, it is important to develop and use profile-screening tools to identify these children