Crowds reaching targets by maximizing entropy: a Clausius-Duhem inequality approach

In this paper we propose the use of concepts from thermodynamics in the study of crowd dynamics. Our continuous model consists of the continuity equation for the density of the crowd and a kinetic equation for the velocity field. The latter includes a nonlocal term that models interactions between individuals. To support our modelling assumptions, we introduce an inequality that resembles the Second Law of Thermodynamics, containing an entropy-like functional. We show that its time derivative equals a positive dissipation term minus a corrector term. The latter term should be small for the time derivative of the entropy to be positive. In case of isotropic interactions the corrector term is absent. For the anisotropic case, we support the claim that the corrector term is small by simulations for the corresponding particle system. They reveal that this term is sufficiently small for the entropy still to increase. Moreover, we show that the entropy converges in time towards a limit value

What explains the variation in estimates of labour supply elasticities?

This paper performs a meta-analysis of empirical estimates of uncompensated labour supply elasticities. We find that much of the variation in elasticities can be explained by the variation in gender, participation rates, and country fixed effects. Country differences appear to be small though. There is no systematic impact of the model specification or marital status on reported elasticities. The decision to participate is more responsive than is the decision regarding hours worked. Even at the intensive margin, we find that the elasticity for women exceeds that for men. For men and women in the Netherlands, we predict an uncompensated labour supply elasticity of 0.1 (or 0.2 if an alternative specification is preferred) and 0.5, respectively. These values are robust for alternative samples and specifications of the meta regression.

Quantum Size Effects in the Atomistic Structure of Armchair-Nanoribbons

Quantum size effects in armchair graphene nano-ribbons (AGNR) with hydrogen termination are investigated via density functional theory (DFT) in Kohn-Sham formulation. "Selection rules" will be formulated, that allow to extract (approximately) the electronic structure of the AGNR bands starting from the four graphene dispersion sheets. In analogy with the case of carbon nanotubes, a threefold periodicity of the excitation gap with the ribbon width (N, number of carbon atoms per carbon slice) is predicted that is confirmed by ab initio results. While traditionally such a periodicity would be observed in electronic response experiments, the DFT analysis presented here shows that it can also be seen in the ribbon geometry: the length of a ribbon with L slices approaches the limiting value for a very large width 1 << N (keeping the aspect ratio small N << L) with 1/N-oscillations that display the electronic selection rules. The oscillation amplitude is so strong, that the asymptotic behavior is non-monotonous, i.e., wider ribbons exhibit a stronger elongation than more narrow ones.Comment: 5 pages, 6 figure

What Explains the Variation in Estimates of Labour Supply Elasticities?

This paper performs a meta-analysis of empirical estimates of uncompensated labour supply elasticities. We find that much of the variation in elasticities can be explained by the variation in gender, participation rates, and country fixed effects. Country differences appear to be small though. There is no systematic impact of the model specification or marital status on reported elasticities. The decision to participate is more responsive than is the decision regarding hours worked. Even at the intensive margin, we find that the elasticity for women exceeds that for men. For men and women in the Netherlands, we predict an uncompensated labour supply elasticity of 0.1 and 0.5, respectively. These values are robust for alternative samples and specifications of the meta regression.labour supply, meta-analysis, uncompensated elasticity

The right expert at the right time and place: From expertise identification to expertise selection

We propose a unified and complete solution for expert finding in organizations, including not only expertise identification, but also expertise selection functionality. The latter two include the use of implicit and explicit preferences of users on meeting each other, as well as localization and planning as important auxiliary processes. We also propose a solution for privacy protection, which is urgently required in view of the huge amount of privacy sensitive data involved. Various parts are elaborated elsewhere, and we look forward to a realization and usage of the proposed system as a whole

Can verbal suggestions strengthen the effects of a relaxation intervention?

Short stress management interventions such as relaxation therapy have demonstrated preliminary effectiveness in reducing stress-related problems. A promising tool to strengthen the effectiveness of relaxation-based interventions is the use of verbal suggestions, as previous research provided evidence that verbal suggestions can induce positive outcome expectancies, facilitate adaptive responses to stress and improve health outcomes. The present experimental proof-of-concept study aimed to investigate the effects of a brief relaxation intervention and specifically the role of verbal suggestions on stress-related outcomes assessed by self-report questionnaires and psychophysiological data. 120 participants (mean age = 22.1 years) were randomized to one of four intervention conditions: a brief relaxation intervention plus verbal suggestions condition, a brief relaxation intervention only condition, a verbal suggestions only condition, and a control condition. Afterwards, participants were subjected to a psychosocial stress challenge to assess reactivity to a stressful event. Immediately after both relaxation interventions (with and without verbal suggestions), lower self-reported state anxiety was found compared to the control condition, but no differences were observed in response to the stressor. The verbal suggestions only condition did not impact state anxiety. No significant effects were found for verbal suggestion interventions on cortisol, alpha amylase, heart rate and skin conductance. This is the first study investigating the role of verbal suggestions in the effectiveness of a brief relaxation intervention. Although this experimental proof-of-concept study provides support for the effectiveness of a brief relaxation intervention in lowering state anxiety directly after the intervention, the effects did not impact the response to a subsequent stressor and we did not observe any evidence for the add-on effectiveness of verbal suggestions. The effectiveness of brief relaxation interventions on stress responses should be investigated further in future research by incorporating interventions that are tailored to the specific stress challenge and various types of verbal suggestions

On the design of an energy-efficient low-latency integrated protocol for distributed mobile sensor networks

Self organizing, wireless sensors networks are an emergent and challenging technology that is attracting large attention in the sensing and monitoring community. Impressive progress has been done in recent years even if we need to assume that an optimal protocol for every kind of sensor network applications can not exist. As a result it is necessary to optimize the protocol for certain scenarios. In many applications for instance latency is a crucial factor in addition to energy consumption. MERLIN performs its best in such WSNs where there is the need to reduce the latency while ensuring that energy consumption is kept to a minimum. By means of that, the low latency characteristic of MERLIN can be used as a trade off to extend node lifetimes. The performance in terms of energy consumption and latency is optimized by acting on the slot length. MERLIN is designed specifically to integrate routing, MAC and localization protocols together. Furthermore it can support data queries which is a typical application for WSNs. The MERLIN protocol eliminates the necessity to have any explicit handshake mechanism among nodes. Furthermore, the reliability is improved using multiple path message propagation in combination with an overhearing mechanism. The protocol divides the network into subsets where nodes are grouped in time zones. As a result MERLIN also shows a good scalability by utilizing an appropriate scheduling mechanism in combination with a contention period

How to keep teachers healthy and growing:The influence of job demands and resources

Purpose – Education depends on high-quality teachers who are committed to professional development and do not get burned out. The purpose of this paper was to investigate how job demands and resources can affect the health and cognitive development of teachers using the Demand-Induced Strain Compensation model. Design/methodology/approach – A cross-sectional sample of 120 teachers in vocational education was used to investigate the proposed relationships and hypotheses with Ordinary Least Squares (OLS) regression method. Findings – In terms of teacher health and development, significant main effects were found for several predictors. Autonomy was significantly and negatively related to emotional exhaustion. Autonomy, emotional supervisor and colleague support were significantly and positively related to teachers’ development. However, little support was found for matching hypotheses, suggesting that matching demands and resources do not offer more explanatory power for occupation outcomes than other types of interaction effects. Research limitations/implications – More powerful analyses techniques like structural equation modeling could be used in future research with a larger sample size. A second limitation is common method variance. Practical implications – Schools in vocational education should provide sufficient job resources, such as autonomy and emotional support, but possibly also put a limit on teacher task variety. Originality/value – Job demands and resources have until now mainly been related to negative outcomes such as poor health and ill-being, while the relationship with learning has also been hypothesized and is therefore meaningful to examine. In addition, it was investigated whether interaction effects of matching demands and resources, better explain these outcomes

‘Thick analysis’: strategie om de kwaliteit van kwalitatieve data-analyse te verhogen

Stelling Kwalitatief onderzoek produceert grote hoeveelheden ruwe data, wat kwalitatieve dataanalyse vaak complex en veeleisend maakt en van de onderzoeker(s) flexibiliteit, ervaring en vaardigheden verlangt. Onze stelling is dat in veel kwalitatief onderzoek aan deze complexiteit onvoldoende recht wordt gedaan, doordat in de dagelijkse praktijk vaak door tijdsdruk de pragmatiek overheerst of vaardigheden ontbreken om tot diepgaande analyse te komen. Daarmee gaat veel van de rijkdom en context van kwalitatieve data verloren. Wij pleiten daarom voor het toepassen van het bekende concept ‘triangulatie’ – traditioneel gedefinieerd als het toepassen van meerdere dataverzamelingsmethoden in een studie – op kwalitatieve data-analyse, om zo de diepte, kwaliteit en eventueel reikwijdte van de bevindingen te vergroten. Analysetriangulatie wordt nog niet veel toegepast, maar is volgens ons een realistische en bruikbare strategie om de methodologische kwaliteit van kwalitatief onderzoek verder te verhogen. Deze strategie is ook geschikt voor onderzoekers die kwalitatief onderzoek doen buiten de ‘academie’. Wij werken een en ander hierna uit