Building communities for the exchange of learning objects: theoretical foundations and requirements

In order to reduce overall costs of developing high-quality digital courses (including both the content, and the learning and teaching activities), the exchange of learning objects has been recognized as a promising solution. This article makes an inventory of the issues involved in the exchange of learning objects within a community. It explores some basic theories, models and specifications and provides a theoretical framework containing the functional and non-functional requirements to establish an exchange system in the educational field. Three levels of requirements are discussed. First, the non-functional requirements that deal with the technical conditions to make learning objects interoperable. Second, some basic use cases (activities) are identified that must be facilitated to enable the technical exchange of learning objects, e.g. searching and adapting the objects. Third, some basic use cases are identified that are required to establish the exchange of learning objects in a community, e.g. policy management, information and training. The implications of this framework are then discussed, including recommendations concerning the identification of reward systems, role changes and evaluation instruments

Interface Modeling for Quality and Resource Management

We develop an interface-modeling framework for quality and resource management that captures configurable working points of hardware and software components in terms of functionality, resource usage and provision, and quality indicators such as performance and energy consumption. We base these aspects on partially-ordered sets to capture quality levels, budget sizes, and functional compatibility. This makes the framework widely applicable and domain independent (although we aim for embedded and cyber-physical systems). The framework paves the way for dynamic (re-)configuration and multi-objective optimization of component-based systems for quality- and resource-management purposes

Event Generation and Statistical Sampling for Physics with Deep Generative Models and a Density Information Buffer

We present a study for the generation of events from a physical process with deep generative models. The simulation of physical processes requires not only the production of physical events, but also to ensure these events occur with the correct frequencies. We investigate the feasibility of learning the event generation and the frequency of occurrence with Generative Adversarial Networks (GANs) and Variational Autoencoders (VAEs) to produce events like Monte Carlo generators. We study three processes: a simple two-body decay, the processes $e^+e^-\to Z \to l^+l^-$ and $p p \to t\bar{t}$ including the decay of the top quarks and a simulation of the detector response. We find that the tested GAN architectures and the standard VAE are not able to learn the distributions precisely. By buffering density information of encoded Monte Carlo events given the encoder of a VAE we are able to construct a prior for the sampling of new events from the decoder that yields distributions that are in very good agreement with real Monte Carlo events and are generated several orders of magnitude faster. Applications of this work include generic density estimation and sampling, targeted event generation via a principal component analysis of encoded ground truth data, anomaly detection and more efficient importance sampling, e.g. for the phase space integration of matrix elements in quantum field theories.Comment: 24 pages, 10 figure

The influence of sensationalist features in television news stories on perceived news quality and perceived sensationalism of viewers in different age groups

This study investigates whether the decreased trust in news media can be explained by the increase in sensationalism in news. To this end, an experiment was conducted in which viewers (N = 288) evaluated sensationalist versus non-sensationalist television news in terms of perceived news quality and perceived sensationalism. Each participant watched four television news stories that varied in the presence of two categories of sensationalism: arousing content and tabloid packaging. Findings showed that sensationalist television news tends to be more negatively evaluated than non-sensationalist news. In addition, critical views on arousing content appeared to be particularly visible among young and middle-aged adults. These findings suggest that the rise of sensationalist news could be an explanation of the declining trust in news media that is witnessed in a number of countries

Function of the fully conserved residues Asp99, Tyr52 and Tyr73 in phospholipase A2

In the active centre of pancreatic phospholipase A2 His48 is at hydrogen-bonding distance to Asp99. This Asp-His couple is assumed to act together with a water molecule as a catalytic triad. Asp99 is also linked via an extended hydrogen bonding system to the side chains of Tyr52 and Tyr73. To probe the function of the fully conserved Asp99, Tyr52 and Tyr73 residues in phospholipase A2, the Asp99 residue was replaced by Asn, and each of the two tyrosines was separately replaced by either a Phe or a Gln. The catalytic and binding properties of the Phe52 and Phe73 mutants did not change significantly relative to the wild-type enzyme. This rules out the possibility that either one of the two Tyr residues in the wild-type enzyme can function as an acyl acceptor or proton donor in catalysis. The Gln73 mutant could not be obtained in any significant amounts probably due to incorrect folding. The Gln52 mutant was isolated in low yield. This mutant showed a large decrease in catalytic activity while its substrate binding was nearly unchanged. The results suggest a structural role rather than a catalytic function of Tyr52 and Tyr73. Substitution of asparagine for aspartate hardly affects the binding constants for both monomeric and micellar substrate analogues. Kinetic characterization revealed that the Asn99 mutant has retained no less than 65% of its enzymatic activity on the monomeric substrate rac 1,2-dihexanoyldithio-propyl-3-phosphocholine, probably due to the fact that during hydrolysis of monomeric substrate by phospholipase A2 proton transfer is not the rate-limiting step. The Asp to Asn substitution decreases the catalytic rate on micellar 1,2-dioctanoyl-sn-glycero-3-phosphocholine 25-fold. To explain this remaining activity we suggest that in the mutant the Asn99 orients His48 in the same way as Asp99 orients His48 in native phospholipase A2 and that the lowered activity is caused by a reduced stabilization of the transition state

Strength training alone, exercise therapy alone, and exercise therapy with passive manual mobilisation each reduce pain and disability in people with knee osteoarthritis: a systematic review

QuestionWhat are the effects of strength training alone, exercise therapy alone, and exercise with additional passive manual mobilisation on pain and function in people with knee osteoarthritis compared to control? What are the effects of these interventions relative to each other?DesignA meta-analysis of randomised controlled trials.ParticipantsAdults with osteoarthritis of the knee.Intervention typesStrength training alone, exercise therapy alone (combination of strength training with active range of motion exercises and aerobic activity), or exercise with additional passive manual mobilisation, versus any non-exercise control. Comparisons between the three interventions were also sought.Outcome measuresThe primary outcome measures were pain and physical function.Results12 trials compared one of the interventions against control. The effect size on pain was 0.38 (95% CI 0.23 to 0.54) for strength training, 0.34 (95% CI 0.19 to 0.49) for exercise, and 0.69 (95% CI 0.42 to 0.96) for exercise plus manual mobilisation. Each intervention also improved physical function significantly. No randomised comparisons of the three interventions were identified. However, meta-regression indicated that exercise plus manual mobilisations improved pain significantly more than exercise alone (p = 0.03). The remaining comparisons between the three interventions for pain and physical function were not significant.ConclusionExercise therapy plus manual mobilisation showed a moderate effect size on pain compared to the small effect sizes for strength training or exercise therapy alone. To achieve better pain relief in patients with knee osteoarthritis physiotherapists or manual therapists might consider adding manual mobilisation to optimise supervised active exercise programs

Hybrid integration on low-cost flex foils using photonic flash soldiering

Soldering of packaged electronic components using industry standard Sn-Ag-Cu (SAC) lead-free solders on low-cost foils, which are often the substrate of choice for flexible electronics, is challenging. This is mainly originating from the fact that the reflow temperatures of these solder alloys are normally higher than the maximum processing temperature of the low-cost flex foils. To enable component integration on the low-cost foils a novel method for soldering has been introduced by Holst Centre as an alternative to oven reflow, termed 'photonic soldering'. In this method high intensity photonic flashes are used to deliver the thermal energy required for soldering. By taking advantage of the selectivity of light absorption, the required energy for soldering is delivered to the components and circuit tracks while excessive heating of the foils is avoided. This paper presents successful photonic flash soldering of packaged LED components on low-cost polyethylene terephthalate (PET) foils using conventional SAC solders as a demonstration of the capabilities of this novel soldering technology

Combined ecological risks of nitrogen and phosphorus in European freshwaters

Eutrophication is a key water quality issue triggered by increasing nitrogen (N) and phosphorus (P) levels and potentially posing risks to freshwater biota. We predicted the probability that an invertebrate species within a community assemblage becomes absent due to nutrient stress as the ecological risk (ER) for European lakes and streams subjected to N and P pollution from 1985 to 2011. The ER was calculated as a function of species-specific tolerances to NO3 - and total P concentrations and water quality monitoring data. Lake and stream ER averaged 50% in the last monitored year (i.e. 2011) and we observed a decrease by 22% and 38% in lake and stream ER (respectively) of river basins since 1985. Additionally, the ER from N stress surpassed that of P in both freshwater systems. The ER can be applied to identify river basins most subjected to eutrophication risks and the main drivers of impacts

Comparison of international guideline programs to evaluate and update the Dutch program for clinical guideline development in physical therapy

<p>Abstract</p> <p>Background</p> <p>Clinical guidelines are considered important instruments to improve quality in health care. Since 1998 the Royal Dutch Society for Physical Therapy (KNGF) produced evidence-based clinical guidelines, based on a standardized program. New developments in the field of guideline research raised the need to evaluate and update the KNGF guideline program.</p> <p>Purpose of this study is to compare different guideline development programs and review the KNGF guideline program for physical therapy in the Netherlands, in order to update the program.</p> <p>Method</p> <p>Six international guideline development programs were selected, and the 23 criteria of the AGREE Instrument were used to evaluate the guideline programs. Information about the programs was retrieved from published handbooks of the organizations. Also, the Dutch program for guideline development in physical therapy was evaluated using the AGREE criteria. Further comparison the six guideline programs was carried out using the following elements of the guideline development processes: Structure and organization; Preparation and initiation; Development; Validation; Dissemination and implementation; Evaluation and update.</p> <p>Results</p> <p>Compliance with the AGREE criteria of the guideline programs was high. Four programs addressed 22 AGREE criteria, and two programs addressed 20 AGREE criteria. The previous Dutch program for guideline development in physical therapy lacked in compliance with the AGREE criteria, meeting only 13 criteria.</p> <p>Further comparison showed that all guideline programs perform systematic literature searches to identify the available evidence. Recommendations are formulated and graded, based on evidence and other relevant factors. It is not clear how decisions in the development process are made. In particular, the process of translating evidence into practice recommendations can be improved.</p> <p>Conclusion</p> <p>As a result of international developments and consensus, the described processes for developing clinical practice guidelines have much in common. The AGREE criteria are common basis for the development of guidelines, although it is not clear how final decisions are made. Detailed comparison of the different guideline programs was used for updating the Dutch program. As a result the updated KNGF program complied with 22 AGREE criteria. International discussion is continuing and will be used for further improvement of the program.</p