The effect of functional roles on group efficiency

The usefulness of ‘roles’ as a pedagogical approach to support small group performance can be often read, however, their effect is rarely empirically assessed. Roles promote cohesion and responsibility and decrease so-called ‘process losses’ caused by coordination demands. In addition, roles can increase awareness of intra-group interaction. In this article, the effect of functional roles on group performance, efficiency and collaboration during computer-supported collaborative learning (CSCL) was investigated with questionnaires and quantitative content analysis of e-mail communication. A comparison of thirty-three questionnaire observations, distributed over ten groups in two research conditions: role (n = 5, N = 14) and non-role (n = 5, N = 19), revealed no main effect for performance (grade). A latent variable was interpreted as ‘perceived group efficiency’ (PGE). Multilevel modelling (MLM) yielded a positive marginal effect of PGE. Groups in the role condition appear to be more aware of their efficiency, compared to groups in the ‘non-role’ condition, regardless whether the group performs well or poor. Content analysis reveals that students in the role condition contribute more ‘task content’ focussed statements. This is, however, not as hypothesised due to the premise that roles decrease coordination and thus increase content focused statements; in fact, roles appear to stimulate coordination and simultaneously the amount of ‘task content’ focussed statements increases

Observation of coherent transients in ultrashort chirped excitation of an undamped two-level system

The effects of Coherent excitation of a two level system with a linearly chirped pulse are studied theoretically and experimentally (in Rb (5s - 5p)) in the low field regime. The Coherent Transients are measured directly on the excited state population on an ultrashort time scale. A sharp step corresponds to the passage through resonance. It is followed by oscillations resulting from interferences between off-resonant and resonant contributions. We finally show the equivalence between this experiment and Fresnel diffraction by a sharp edge.Comment: 4 pages, 4 figures, to appear in PR

Floquet dynamics in light-driven solids

We demonstrate how the properties of light-induced electronic Floquet states in solids impact natural physical observables, such as transport properties, by capturing the environmental influence on the electrons. We include the environment as dissipative processes, such as inter-band decay and dephasing, often ignored in Floquet predictions. These dissipative processes determine the Floquet band occupations of the emergent steady state, by balancing out the optical driving force. In order to benchmark and illustrate our framework for Floquet physics in a realistic solid, we consider the light-induced Hall conductivity in graphene recently reported by J.~W.~McIver, et al., Nature Physics (2020). We show that the Hall conductivity is estimated by the Berry flux of the occupied states of the light-induced Floquet bands, in addition to the kinetic contribution given by the average band velocity. Hence, Floquet theory provides an interpretation of this Hall conductivity as a geometric-dissipative effect. We demonstrate this mechanism within a master equation formalism, and obtain good quantitative agreement with the experimentally measured Hall conductivity, underscoring the validity of this approach which establishes a broadly applicable framework for the understanding of ultrafast non-equilibrium dynamics in solids

Clinical translation of the assets of biomedical engineering - a retrospective analysis with looks to the future

Introduction: Biomedical-engineering (BME) plays a major role in modern medicine. Many BME-based assets have been brought to clinical translation in the twentieth century, but translation currently stagnates. Here, we compare the impact of past and present scientific, economic and societal climates on the translation of BME-based assets, in order to provide the BME-community with incentives to address current stagnation. Areas covered: In the twentieth century, W.J. Kolff brought kidney dialysis, the total artificial heart, artificial vision and limbs to clinical application. This success raises the question whether Kolff and other past giants of clinical translation had special mind-sets, or whether their problem selection, their training, or governmental and regulatory control played roles. Retrospective analysis divides the impact of BME-based assets to clinical application into three periods: 1900-1970: rapid translation from bench-to-bedside, 1970-1990: new diseases and increased governmental control, and the current translational crisis from 1990 onward. Expert opinion: Academic and societal changes can be discerned that are concurrent with BME's translational success: mono-disciplinary versus multi-disciplinary training, academic reward systems based on individual achievements versus team achievements with strong leadership, increased governmental and regulatory control, and industrial involvement. From this, recommendations can be derived for accelerating clinical translation of BME-assets

Long-Term Evolution and Revival Structure of Rydberg Wave Packets for Hydrogen and Alkali-Metal Atoms

This paper begins with an examination of the revival structure and long-term evolution of Rydberg wave packets for hydrogen. We show that after the initial cycle of collapse and fractional/full revivals, which occurs on the time scale $t_{\rm rev}$, a new sequence of revivals begins. We find that the structure of the new revivals is different from that of the fractional revivals. The new revivals are characterized by periodicities in the motion of the wave packet with periods that are fractions of the revival time scale $t_{\rm rev}$. These long-term periodicities result in the autocorrelation function at times greater than $t_{\rm rev}$ having a self-similar resemblance to its structure for times less than $t_{\rm rev}$. The new sequence of revivals culminates with the formation of a single wave packet that more closely resembles the initial wave packet than does the full revival at time $t_{\rm rev}$, i.e., a superrevival forms. Explicit examples of the superrevival structure for both circular and radial wave packets are given. We then study wave packets in alkali-metal atoms, which are typically used in experiments. The behavior of these packets is affected by the presence of quantum defects that modify the hydrogenic revival time scales and periodicities. Their behavior can be treated analytically using supersymmetry-based quantum-defect theory. We illustrate our results for alkali-metal atoms with explicit examples of the revival structure for radial wave packets in rubidium.Comment: To appear in Physical Review A, vol. 51, June 199

How dentists and oral and maxillofacial surgeons deal with tooth extraction without a valid clinical indication

Objectives: This study pertains to a secondary data analysis aimed at determining differences between oral and maxillofacial surgeons (OMFSs) and dentists handling dental extractions without an evident clinical indication. Study design: A survey of 18 questions was conducted among 256 OMFSs in the Netherlands and a random sample of 800 dentists Respondents could answer the questions in writing or online. The data was collected in the period from November 2019 to January 2020, during which two reminders were sent. Analysis of the data took place via descriptive statistics and Chi Square test. Results: The response rate was 28.1% (n = 72) for OMFSs and 30.3% (n = 242) for dentists. In the past three years, 81.9% (n = 59) of the OMFSs and 68.0% (n = 164) of the dentists received a request for extraction without a clinical indication. The most common reasons were financial and severe dental fear (OMFSs: 64.9 and 50.9% vs dentists: 77.4 and 36.5%). Dentists were significantly more likely (75.6%, n = 114) than OMFS (60.7%, n = 34) to comply with their last extraction request without a clinical indication. Almost none of them regretted the extraction afterwards. As for the request itself, it was found that 17.5% (n = 10) of the OMFSs and 12.5% (n = 20) of the dentists did not check for patients’ mental competency (p = 0.352). Conclusions: Given that most of the interviewed dental professionals complied with non-dental extraction requests when such extractions are ethically and legally precarious, recommendations for handling such requests are greatly needed

The effect of functional roles on perceived group efficiency during computer-supported collaborative learning

In this article, the effect of functional roles on group performance and collaboration during computer-supported collaborative learning (CSCL) is investigated. Especially the need for triangulating multiple methods is emphasised: Likert-scale evaluation questions, quantitative content analysis of e-mail communication and qualitative analysis of open-ended questions were used. A comparison of fourty-one questionnaire observations, distributed over thirteen groups in two research conditions – groups with prescribed functional roles (n = 7, N = 18) and nonrole groups (n = 6, N = 23) – revealed no main effect for performance (grade). Principal axis factoring of the Likert-scales revealed a latent variable that was interpreted as perceived group efficiency (PGE). Multilevel modelling (MLM) yielded a positive marginal effect of PGE. Most groups in the role condition report a higher degree of PGE than nonrole groups. Content analysis of e-mail communication of all groups in both conditions (role n = 7, N = 25; nonrole n = 6, N = 26) revealed that students in role groups contribute more ‘coordination’ focussed statements. Finally, results from cross case matrices of student responses to open-ended questions support the observed marginal effect that most role groups report a higher degree of perceived group efficiency than nonrole groups

Personality traits, ventricular tachyarrhythmias, and mortality in patients with an implantable cardioverter defibrillator: 6 years follow-up of the WEBCARE cohort

Objective: Risk stratification within the ICD population warrants the examining of the role of protective- and risk factors. Current study examines the association between Type D personality, pessimism, and optimism and risk of ventricular tachyarrhythmias (VTa's) and mortality in patients with a first-time ICD 6 years post implantation. Methods: A total of 221 first-implant ICD patients completed questionnaires on optimism and pessimism (Life Orientation Test) and Type D personality (Type D scale DS14) 10 to 14 days after implantation. VTa's and all-cause mortality 6 years post implant comprised the study endpoints. Results: Ninety (40.7%) patients had experienced VTa's and 37 (16.7%) patients died, 12 (5.4%) due to a cardiac cause. Adjusted logistic regression analysis showed that pessimism was significantly associated with increased risk of VTa's (OR = 1.09; 95% CI = 1.00–1.19; p =.05). Type D personality (OR = 1.05; 95% CI = 0.47–2.32; p =.91) and optimism (OR = 1.00; 95% CI = 0.90–1.12; p =.98) were not associated with VTa's. None of the personality types were associated with mortality. Conclusion: Pessimism was associated with VTa's but not with mortality. No significant association with either of the endpoints was observed for Type D personality and optimism. Future research should focus on the coexistent psychosocial factors that possibly lead to adverse cardiac prognosis in this patient population

'The Germans are Hydrophobes': Germany and the Germans in the Shaping of French Identity

This article addresses issues of national identity and nationalism in the age of the French Revolution by looking at French attitudes towards the Germans. It engages with theories of nationalism while presenting empirical evidence gleaned from archival research. This material, sometimes grimly, sometimes rather amusingly, reveals much about French ideas and prejudices about the Germans and how it reflected back on the revolutionary and Napoleonic sense of what it meant to be French