Formative peer assessment in a CSCL environment

In this case study our aim was to gain more insight in the possibilities of qualitative formative peer assessment in a computer supported collaborative learning (CSCL) environment. An approach was chosen in which peer assessment was operationalised in assessment assignments and assessment tools that were embedded in the course material. The course concerned a higher education case-based virtual seminar, in which students were asked to conduct research and write a report in small multidisciplinary teams. The assessment assignments contained the discussion of assessment criteria, the assessment of a group report of a fellow group, and writing an assessment report. A list of feedback rules was one of the assessment tools. A qualitative oriented study was conducted, focussing on the attitude of students towards peer assessment and practical use of peer assessment assignments and tools. Results showed that students’ attitude towards peer assessment was positive and that assessment assignments had added value. However, not all students fulfilled all assessment assignments. Recommendations for implementation of peer assessment in CSCL environments as well as suggestions for future research are discussed

Effect of dexamethasone on quality of life in children with acute lymphoblastic leukaemia: a prospective observational study

<p>Abstract</p> <p>Background</p> <p>Glucocorticoids are important in the treatment of childhood acute lymphoblastic leukaemia (ALL). However, cyclic administration of high dose glucocorticoids may cause rapid and substantial changes in quality of life (QoL). The maintenance phase of the Dutch ALL-9 protocol consisted of alternating two weeks on and five weeks off dexamethasone (6 mg/m²/day). The present study was performed to assess the effect of dexamethasone on QoL during treatment for ALL according to this protocol.</p> <p>Methods</p> <p>In a multicentre prospective cohort study, QoL was assessed halfway (T1) and at the end of the two-year treatment (T2). A generic (Child Health Questionnaire) and disease specific (PedsQL™ cancer version) QoL questionnaire were used to assess QoL in two periods: on and off dexamethasone, respectively.</p> <p>Results</p> <p>41 children (56% males) were evaluated, mean age at diagnosis was 5.6 years. The CHQ physical and psychosocial summary scores were significantly lower than population norms. At T1 and T2, overall QoL showed no significant change. However, regarding specific domains (pain, cognitive functioning, emotion/behaviour and physical functioning) QoL decreased over time. QoL was significantly more impaired during periods on dexamethasone.</p> <p>Conclusion</p> <p>Dexamethasone was associated with decreased QoL. At the end of treatment, reported QoL during dexamethasone deteriorated even more on certain scales (pain, cognitive functioning, emotion/behaviour and physical functioning). Knowledge of the specific aspects of QoL is essential to improve counselling and coping in paediatric oncology. Adverse effects of specific drugs on QoL should be taken into account when designing treatment protocols.</p

The hemodynamic tolerability and feasibility of sustained low efficiency dialysis in the management of critically ill patients with acute kidney injury

<p>Abstract</p> <p>Background</p> <p>Minimization of hemodynamic instability during renal replacement therapy (RRT) in patients with acute kidney injury (AKI) is often challenging. We examined the relative hemodynamic tolerability of sustained low efficiency dialysis (SLED) and continuous renal replacement therapy (CRRT) in critically ill patients with AKI. We also compared the feasibility of SLED administration with that of CRRT and intermittent hemodialysis (IHD).</p> <p>Methods</p> <p>This cohort study encompassed four critical care units within a single university-affiliated medical centre. 77 consecutive critically ill patients with AKI who were treated with CRRT (n = 30), SLED (n = 13) or IHD (n = 34) and completed at least two RRT sessions were included in the study. Overall, 223 RRT sessions were analyzed. Hemodynamic instability during a given session was defined as the composite of a > 20% reduction in mean arterial pressure or any escalation in pressor requirements. Treatment feasibility was evaluated based on the fraction of the prescribed therapy time that was delivered. An interrupted session was designated if < 90% of the prescribed time was administered. Generalized estimating equations were used to compare the hemodynamic tolerability of SLED vs CRRT while accounting for within-patient clustering of repeated sessions and key confounders.</p> <p>Results</p> <p>Hemodynamic instability occurred during 22 (56.4%) SLED and 43 (50.0%) CRRT sessions (p = 0.51). In a multivariable analysis that accounted for clustering of multiple sessions within the same patient, the odds ratio for hemodynamic instability with SLED was 1.20 (95% CI 0.58-2.47), as compared to CRRT. Session interruption occurred in 16 (16.3), 30 (34.9) and 11 (28.2) of IHD, CRRT and SLED therapies, respectively.</p> <p>Conclusions</p> <p>In critically ill patients with AKI, the administration of SLED is feasible and provides comparable hemodynamic control to CRRT.</p

The Biological Basis of a Universal Constraint on Color Naming: Cone Contrasts and the Two-Way Categorization of Colors

Many studies have provided evidence for the existence of universal constraints on color categorization or naming in various languages, but the biological basis of these constraints is unknown. A recent study of the pattern of color categorization across numerous languages has suggested that these patterns tend to avoid straddling a region in color space at or near the border between the English composite categories of “warm” and “cool”. This fault line in color space represents a fundamental constraint on color naming. Here we report that the two-way categorization along the fault line is correlated with the sign of the L- versus M-cone contrast of a stimulus color. Moreover, we found that the sign of the L-M cone contrast also accounted for the two-way clustering of the spatially distributed neural responses in small regions of the macaque primary visual cortex, visualized with optical imaging. These small regions correspond to the hue maps, where our previous study found a spatially organized representation of stimulus hue. Altogether, these results establish a direct link between a universal constraint on color naming and the cone-specific information that is represented in the primate early visual system

A Profile Likelihood Analysis of the Constrained MSSM with Genetic Algorithms

The Constrained Minimal Supersymmetric Standard Model (CMSSM) is one of the simplest and most widely-studied supersymmetric extensions to the standard model of particle physics. Nevertheless, current data do not sufficiently constrain the model parameters in a way completely independent of priors, statistical measures and scanning techniques. We present a new technique for scanning supersymmetric parameter spaces, optimised for frequentist profile likelihood analyses and based on Genetic Algorithms. We apply this technique to the CMSSM, taking into account existing collider and cosmological data in our global fit. We compare our method to the MultiNest algorithm, an efficient Bayesian technique, paying particular attention to the best-fit points and implications for particle masses at the LHC and dark matter searches. Our global best-fit point lies in the focus point region. We find many high-likelihood points in both the stau co-annihilation and focus point regions, including a previously neglected section of the co-annihilation region at large m_0. We show that there are many high-likelihood points in the CMSSM parameter space commonly missed by existing scanning techniques, especially at high masses. This has a significant influence on the derived confidence regions for parameters and observables, and can dramatically change the entire statistical inference of such scans.Comment: 47 pages, 8 figures; Fig. 8, Table 7 and more discussions added to Sec. 3.4.2 in response to referee's comments; accepted for publication in JHE

Impact of Polychlorinated Biphenyls Contamination on Estrogenic Activity in Human Male Serum

Polychlorinated biphenyls (PCBs) are thought to cause numerous adverse health effects, but their impact on estrogen signaling is still not fully understood. In the present study, we used the ER-CALUX bioassay to determine estrogenic/antiestrogenic activities of the prevalent PCB congeners and PCB mixtures isolated from human male serum. The samples were collected from residents of an area with an extensive environmental contamination from a former PCB production site as well as from a neighboring background region in eastern Slovakia. We found that the lower-chlorinated PCBs were estrogenic, whereas the prevalent higher-chlorinated PCB congeners 138, 153, 170, 180, 187, 194, 199, and 203, as well as major PCB metabolites, behaved as anti-estrogens. Coplanar PCBs had no direct effect on estrogen receptor (ER) activation in this in vitro model. In human male serum samples, high levels of PCBs were associated with a decreased ER-mediated activity and an increased dioxin-like activity, as determined by the DR-CALUX assay. 17β-Estradiol (E(2)) was responsible for a major part of estrogenic activity identified in total serum extracts. Significant negative correlations were found between dioxin-like activity, as well as mRNA levels of cytochromes P450 1A1 and 1B1 in lymphocytes, and total estrogenic activity. For sample fractions containing only persistent organic pollutants (POPs), the increased frequency of anti-estrogenic samples was associated with a higher sum of PCBs. This suggests that the prevalent non-dioxin-like PCBs were responsible for the weak antiestrogenic activity of some POPs fractions. Our data also suggest that it might be important to pay attention to direct effects of PCBs on steroid hormone levels in heavily exposed subjects

Local Difference Measures between Complex Networks for Dynamical System Model Evaluation

Acknowledgments We thank Reik V. Donner for inspiring suggestions that initialized the work presented herein. Jan H. Feldhoff is credited for providing us with the STARS simulation data and for his contributions to fruitful discussions. Comments by the anonymous reviewers are gratefully acknowledged as they led to substantial improvements of the manuscript.Peer reviewedPublisher PD

Comparison of analyses of the QTLMAS XII common dataset. I: Genomic selection

<p>Abstract</p> <p>A dataset was simulated and distributed to participants of the QTLMAS XII workshop who were invited to develop genomic selection models. Each contributing group was asked to describe the model development and validation as well as to submit genomic predictions for three generations of individuals, for which they only knew the genotypes. The organisers used these genomic predictions to perform the final validation by comparison to the true breeding values, which were known only to the organisers. Methods used by the 5 groups fell in 3 classes 1) fixed effects models 2) BLUP models, and 3) Bayesian MCMC based models. The Bayesian analyses gave the highest accuracies, followed by the BLUP models, while the fixed effects models generally had low accuracies and large error variance. The best BLUP models as well as the best Bayesian models gave unbiased predictions. The BLUP models are clearly sensitive to the assumed SNP variance, because they do not estimate SNP variance, but take the specified variance as the true variance. The current comparison suggests that Bayesian analyses on haplotypes or SNPs are the most promising approach for Genomic selection although the BLUP models may provide a computationally attractive alternative with little loss of efficiency. On the other hand fixed effect type models are unlikely to provide any gain over traditional pedigree indexes for selection.</p