A multicase study for the evaluation of a pattern-based visual design process for collaborative learning

Collage is a pattern-based visual design authoring tool for the creation of collaborative learning scripts computationally modelled with IMS Learning Design (LD). The pattern-based visual approach aims to provide teachers with design ideas that are based on broadly accepted practices. Besides, it seeks hiding the LD notation so that teachers can easily create their own designs. The use of visual representations supports both the understanding of the design ideas and the usability of the authoring tool. This paper presents a multicase study comprising three different cases that evaluate the approach from different perspectives. The first case includes workshops where teachers use Collage. A second case implies the design of a scenario proposed by a third-party using related approaches. The third case analyzes a situation where students follow a design created with Collage. The cross-case analysis provides a global understanding of the possibilities and limitations of the pattern-based visual design approach.

Free-and open source software for a course on network management: authoring and enactment of scripts based on collaborative learning strategies

This paper describes a Computer-Supported Collaborative Learning (CSCL) case study in engineering education carried out within the context of a network management course. The case study shows that the use of two computing tools developed by the authors and based on Free- and Open-Source Software (FOSS) provide significant educational benefits over traditional engineering pedagogical approaches in terms of both concepts and engineering competencies acquisition. First, the Collage authoring tool guides and supports the course teacher in the process of authoring computer-interpretable representations (using the IMS Learning Design standard notation) of effective collaborative pedagogical designs. Besides, the Gridcole system supports the enactment of that design by guiding the students throughout the prescribed sequence of learning activities. The paper introduces the goals and context of the case study, elaborates onhow Collage and Gridcole were employed, describes the applied evaluation methodology, anddiscusses the most significant findings derived from the case study.

Reusing IMS-LD formalized best practices in collaborative learning structuring

Designs of CSCL (Computer Supported Collaborative Learning)activities should be flexible, effective and customizable toparticular learning situations. On the other hand, structureddesigns aim to create favourable conditions for learning. Thus,this paper proposes the collection of representative and broadlyaccepted (best practices) structuring techniques in collaborative learning. With the aim of establishing a conceptual common ground among collaborative learning practitioners and softwaredevelopers, and reusing the expertise that best practicesrepresent, the paper also proposes the formulation of these techniques as patterns: the so-called CLFPs (CollaborativeLearning Flow Patterns). To formalize these patterns, we havechosen the educational modelling language IMS Learning Design (IMS-LD). IMS-LD has the capability to specify many of the collaborative characteristics of the CLFPs. Nevertheless, the language bears limited capability for describing the services that mediate interactions within a learning activity and the specification of temporal or rotated roles. This analysis isdiscussed in the paper, as well as our approaches towards thedevelopment of a system capable of integrating tools using IMSLDscripts and a CLFP-based Learning Design authoring tool.

Differential DNA extraction of challenging simulated sexual assault samples: a Swiss collaborative study.

ABSTRACT: In sexual assault cases, autosomal DNA analysis of gynecological swabs is a challenge, as the presence of a large quantity of female material may prevent the detection of the male DNA. A solution to this problem is differential DNA extraction, but as there are different protocols, it was decided to test their efficiency on simulated casework samples. Four difficult samples were sent to the nine Swiss laboratories active in the forensic genetics. They used their routine protocols to separate the epithelial cell fraction, enriched with the non-sperm DNA, from the sperm fraction. DNA extracts were then sent to the organizing laboratory for analysis. Estimates of male to female DNA ratio without differential DNA extraction ranged from 1:38 to 1:339, depending on the semen used to prepare the samples. After differential DNA extraction, most of the ratios ranged from 1:12 to 9:1, allowing the detection of the male DNA. Compared to direct DNA extraction, cell separation resulted in losses of 94-98% of the male DNA. As expected, more male DNA was generally present in the sperm than in the epithelial cell fraction. However, for about 30% of the samples, the reverse trend was observed. The recovery of male and female DNA was highly variable depending on the laboratories. Experimental design similar to the one used in this study may help for local protocol testing and improvement.

Under- and over-water halves of Gyrinidae beetle eyes harbor different corneal nanocoatings providing adaptation to the water and air environments.

Whirligig beetles (Gyrinidae) inhabit water surfaces and possess unique eyes which are split into the overwater and underwater parts. In this study we analyze the micro- and nanostructure of the split eyes of two Gyrinidae beetles genera, Gyrinus and Orectochilus. We find that corneae of the overwater ommatidia are covered with maze-like nanostructures, while the corneal surface of the underwater eyes is smooth. We further show that the overwater nanostructures possess no anti-wetting, but the anti-reflective properties with the spectral preference in the range of 450-600 nm. These findings illustrate the adaptation of the corneal nanocoating of the two halves of an insect's eye to two different environments. The novel natural anti-reflective nanocoating we describe may find future technological applications.

Survey on batch-to-batch variation in spray paints: a collaborative study

This study represents the most extensive analysis of batch-to-batch variations in spray paint samples to date. The survey was performed as a collaborative project of the ENFSI (European Network of Forensic Science Institutes) Paint and Glass Working Group (EPG) and involved 11 laboratories. Several studies have already shown that paint samples of similar color but from different manufacturers can usually be differentiated using an appropriate analytical sequence. The discrimination of paints from the same manufacturer and color (batch-to-batch variations) is of great interest and these data are seldom found in the literature. This survey concerns the analysis of batches from different color groups (white, papaya (special shade of orange), red and black) with a wide range of analytical techniques and leads to the following conclusions. Colored batch samples are more likely to be differentiated since their pigment composition is more complex (pigment mixtures, added pigments) and therefore subject to variations. These variations may occur during the paint production but may also occur when checking the paint shade in quality control processes. For these samples, techniques aimed at color/pigment(s) characterization (optical microscopy, microspectrophotometry (MSP), Raman spectroscopy) provide better discrimination than techniques aimed at the organic (binder) or inorganic composition (fourier transform infrared spectroscopy (FTIR) or elemental analysis (SEM - scanning electron microscopy and XRF - X-ray fluorescence)). White samples contain mainly titanium dioxide as a pigment and the main differentiation is based on the binder composition (Csingle bondH stretches) detected either by FTIR or Raman. The inorganic composition (elemental analysis) also provides some discrimination. Black samples contain mainly carbon black as a pigment and are problematic with most of the spectroscopic techniques. In this case, pyrolysis-GC/MS represents the best technique to detect differences. Globally, Py-GC/MS may show a high potential of discrimination on all samples but the results are highly dependent on the specific instrumental conditions used. Finally, the discrimination of samples when data was interpreted visually as compared to statistically using principal component analysis (PCA) yielded very similar results. PCA increases sensitivity and could perform better on specific samples, but one first has to ensure that all non-informative variation (baseline deviation) is eliminated by applying correct pre-treatments. Statistical treatments can be used on a large data set and, when combined with an expert's opinion, will provide more objective criteria for decision making.

Application of the 2008 definitions for invasive fungal diseases to the trial comparing voriconazole versus amphotericin B for therapy of invasive aspergillosis: a collaborative study of the Mycoses Study Group (MSG 05) and the European Organization for Research and Treatment of Cancer Infectious Diseases Group.

BACKGROUND: Strict definition of invasive aspergillosis (IA) cases is required to allow precise conclusions about the efficacy of antifungal therapy. The Global Comparative Aspergillus Study (GCAS) compared voriconazole to amphotericin B (AmB) deoxycholate for the primary therapy of IA. Because predefined definitions used for this trial were substantially different from the consensus definitions proposed by the European Organization for Research and Treatment of Cancer/Mycoses Study Group in 2008, we recategorized the 379 episodes of the GCAS according to the later definitions. METHODS: The objectives were to assess the impact of the current definitions on the classification of the episodes and to provide comparative efficacy for probable/proven and possible IA in patients treated with either voriconazole or AmB. In addition to original data, we integrated the results of baseline galactomannan serum levels obtained from 249 (65.7%) frozen samples. The original response assessment was accepted unchanged. RESULTS: Recategorization allowed 59 proven, 178 probable, and 106 possible IA cases to be identified. A higher favorable 12-week response rate was obtained with voriconazole (54.7%) than with AmB (29.9%) (P < .0001). Survival was higher for voriconazole for mycologically documented (probable/proven) IA (70.2%) than with AmB (54.9%) (P = .010). Higher response rates were obtained in possible IA treated with voriconazole vs AmB with the same magnitude of difference (26.2%; 95% confidence interval [CI], 7.2%-45.3%) as in mycologically documented episodes (24.3%; 95% CI, 11.9%-36.7%), suggesting that possible cases are true IA. CONCLUSIONS: Recategorization resulted in a better identification of the episodes and confirmed the higher efficacy of voriconazole over AmB deoxycholate in mycologically documented IA.

Psychological pressure in competitive environments: Evidence from a randomized natural experiment

Much like cognitive abilities, emotional skills can have major effects on performance and economic outcomes. This paper studies the behavior of professionalsubjects involved in a dynamic competition in their own natural environment. Thesetting is a penalty shoot-out in soccer where two teams compete in a tournamentframework taking turns in a sequence of five penalty kicks each. As the kicking order is determined by the random outcome of a coin flip, the treatment and control groups are determined via explicit randomization. Therefore, absent any psychological effects, both teams should have the same probability of winning regardless of the kicking order. Yet, we find a systematic first-kicker advantage. Using data on 2,731 penalty kicks from 262 shoot-outs for a three decade period, we find that teams kicking first win the penalty shoot-out 60.5% of the time. A dynamic panel data analysis shows that the psychological mechanism underlying this result arises from the asymmetry in the partial score. As most kicks are scored, kicking first typically means having the opportunity to lead in the partial score, whereas kicking second typically means lagging in the score and having the opportunity to, at most, get even. Having a worse prospect than the opponent hinders subjects' performance.Further, we also find that professionals are self-aware of their own psychological effects. When a recent change in regulations gives winners of the coin toss the chance to choose the kicking order, they rationally react to it by systematically choosing to kick first. A survey of professional players reveals that when asked to explain why they prefer to kick first, they precisely identify the psychological mechanism for which we find empirical support in the data: they want to lead in the score inorder to put pressure on the opponent.

Decision making in uncertain and changing environments

We consider an agent who has to repeatedly make choices in an uncertainand changing environment, who has full information of the past, who discountsfuture payoffs, but who has no prior. We provide a learning algorithm thatperforms almost as well as the best of a given finite number of experts orbenchmark strategies and does so at any point in time, provided the agentis sufficiently patient. The key is to find the appropriate degree of forgettingdistant past. Standard learning algorithms that treat recent and distant pastequally do not have the sequential epsilon optimality property.

Carabid beetle assemblages in three environments in the Araucaria humid forest of southern Brazil

Carabid beetle assemblages in three environments in the Araucaria humid forest of southern Brazil. Carabidae is composed mainly by ground-dwelling predator beetles. It is the fourth most diverse group within Coleoptera, but its diversity in the Neotropical region is understudied. Here we describe and analyze the diversity of carabid beetles in a region of subtropical rain forest dominated by Araucaria angustifolia with different landscapes. Three areas were chosen in an environmental integrity gradient: primary forests, secondary forests and old Pinus plantations. Pitfall traps were taken monthly, in a total of 14 samples per area. 1733 adult carabid beetles, belonging to 18 species, were sampled. There were differences in richness and abundance between the sampled areas. The total scores followed the same tendency: primary forests (14 species/747 individuals), secondary forests (13/631) and Pinus forests (10/355). An analysis of similarity shows differences in species composition, for both areas and seasons. Galerita lacordarei was the most abundant species for all samples and seasons. Carabid species show similar responses in accordance with habitat heterogeneity and disturbance. The abundance of Galerita lacordarei was influenced by temperature, for all sampled sites. Environmental changes affect the carabid assemblages and decrease diversity, possibly interfering in local dynamics. Seasonality patterns seem to indicate an increase in individual movement during summer, probably in search of resources. It is suggested that microhabitat patchiness is probably an important factor affecting carabid beetle diversity at small spatial scales.

Biosphere/lithosphere interface : microbially-mediated CaCO3 precipitation in hypersaline and freshwater environments

Abstract: Microbial mats very efficiently cycle elements, such as C, 0, N, S and H, which makes them key players of redox processes at the biosphere-lithosphere interface. They are characterized by high metabolic activities and high turnover rates (production and consumption) of biomass, which mainly consists of cell material and of extracellular organic matter (EOM). The EOM forms a matrix, embedding the microbial cells and fulfilling various functions within the microbial mat, including: mat attachment to surfaces; creation of micro-domains within the mat; physical stabilization under hy- drodynamic stress and the protection of the cells in multiple other stress conditions. EOM mainly consists of polysaccharides, amino acids, and a variety of chemical func-tional groups {e.g., -C00H, - SH -OH). These groups strongly bind cations such as Ca2+ and Mg2+ and thus exert a strong control on carbonate mineral formation within the microbial mat. A feedback mechanism between community metabolisms, their prod¬ucts, and the surrounding physicochemical microenvironment thus influences the de¬gree of carbonate saturation favoring either carbonate precipitation or dissolution. We investigated the driving forces and mechanisms of microbialite formation in the Sari ne River, FR, Switzerland, the hypersaline lake, Big Pond, Bahamas and in labo¬ratory experiments. The two fundamentally different natural systems allowed us to compare the geochemical conditions and microbial metabolisms, necessary for car¬bonate formation in microbial mats. Although carbonates are oversaturated in both environments, precipitation does not occur on physicochemical substrates (i.e. out¬side the microbial mats). In the Sarine a high crystal nucleation threshold exceeds the carbonate saturation, despite the high carbonate alkalinity in the water column. Cyanobacterial photosynthesis strongly locally enhances the carbonate alkalinity, whereas the EOM attract and immobilize calcium, which increases the saturation state and finally leads to carbonate precipitation within the EOM (in this case the cyanobacterial sheath) as nucleation template. In Big Pond, the presence of calcium- chelating anions (i.e. sulfate) and EOM, as well as the presence of magnesium, lowers the calcium activity in the water column and mat, and thus inhibits carbonate pre¬cipitation. Coupled with other heterotrophic metabolisms, sulfate reduction uses the EOM as carbon source, degrading it. The resulting EOM consumption creates alkalin¬ity, releases calcium and consumes sulfate in mat-micro domains, which leads to the formation of carbonate layers at the top of the microbial mat. Résumé: Interface biosphère/lithosphère: médiation microbienne de la précipitation de CaC03 dans des environnements en eaux douces et hypersalines Les tapis microbiens engendrent une circulation très efficace des éléments, tels que C, 0, N, S et H, ce qui en fait des acteurs clé pour les processus d'oxydoréduction à l'inter¬face biosphère-lithosphère. Ils sont caractérisés par des taux élevés d'activité méta¬bolique, ainsi que par la production et la consommation de biomasse, principalement constituée de cellules microbiennes et de matière organique extracellulaire (MOE). Dans un tapis microbien, les cellules microbiennes sont enveloppées par une matrice de MOE qui a différentes fonctions dont l'attachement du tapis aux surfaces, la créa¬tion de micro-domaines dans le tapis, la stabilisation physique en situation de stress hydrodynamique, et la protection des cellules dans de multiples autres conditions de stress. La MOE se compose principalement de polysaccharides, d'acides aminés, et d'une variété de groupes fonctionnels chimiques (par exemple, COOH, -SH et -OH). Ces groupes se lient fortement aux cations, tels que Ca2+ et Mg2+, et exercent ainsi un contrôle fort sur la formation de CaC03 dans le tapis microbien. Un mécanisme de rétroaction, entre les métabolismes de la communauté microbienne, leurs produits, et le microenvironnement physico-chimique, influence le degré de saturation de car¬bonate, favorisant soit leur précipitation, soit leur dissolution. Nous avons étudié le moteur et les mécanismes de minéralisation dans des tapis de la Sarine, FR, Suisse et du lac hypersalin, Big Pond, aux Bahamas, ainsi que durant des expériences en laboratoire. Les deux systèmes naturels, fondamentalement dif¬férents, nous ont permis de comparer les conditions géochimiques et les métabolis¬mes nécessaires à la formation des carbonates dans des tapis microbiens. Bien que les carbonates soient sursaturés dans les deux environnements, la précipitation ne se produit pas sur des substrats physico-chimiques (en dehors du tapis microbien). Dans la Sarine, malgré un taux d'alcalinité élevé, les valeurs de seuil pour la nucléa- tion de carbonates sont plus hautes que la saturation du carbonate. La photosynthèse cyanobactérienne augmente localement l'alcalinité, alors que la MOE attire et immo¬bilise le calcium, ce qui augmente l'état de saturation et conduit finalement à la pré¬cipitation des carbonates, en utilisant la MOE comme substrat de nucléation. À Big Pond, la présence de chélateurs de calcium, notamment les anions (p.ex. le sulfate) et la MOE, ainsi que la présence de magnésium, réduit l'activité du calcium et inhibe en conséquence la précipitation des carbonates. Couplée avec d'autres métabolismes hétérotrophes, la réduction des sulfates utilise la MOE comme source de carbone, en la dégradant. Cette consommation de MOE crée l'alcalinité, consomme des sulfates et libère du calcium dans des micro-domaines, conduisant à la formation de couches de carbonates dans le haut du tapis microbien.

Characterization and Application of Educational Virtual Environments for Science Teaching in Secondary School

This work describes the characteristics of a representative set of seven different virtual laboratories (VLs) aimed for science teaching in secondary school. For this purpose, a 27-item evaluation model that facilitates the characterization of the VLs was prepared. The model takes into account the gaming features, the overall usability, and also the potential to induce scientific literacy. Five of the seven VLs were then tested with two larger and highly heterogenic groups of students, and in two different contexts – biotechnology and physics, respectively. It is described how the VLs were received by the students, taking into account both their motivation and their self-reported learning outcome. In some cases, students’ approach to work with the VLs was recorded digitally, and analyzed qualitatively. In general, the students enjoyed the VL activities, and claimed that they learned from them. Yet, more investigation is required to address the effectiveness of these tools for significant learning.