Service and device discovery of nodes in a wireless sensor network

Emerging wireless communication standards and more capable sensors and actuators have pushed further development of wireless sensor networks. Deploying a large number of sensor\ud nodes requires a high-level framework enabling the devices to present themselves and the resources they hold. The device and the resources can be described as services, and in this paper, we review a number of well-known service discovery protocols. Bonjour stands out with its auto-configuration, distributed architecture, and sharing of resources. We also present a lightweight implementation in order to demonstrate that an emerging standards-based device and service discovery protocol can actually be deployed on small wireless sensor nodes

Enhanced heat flow in the hydrodynamic-collisionless regime

We study the heat conduction of a cold, thermal cloud in a highly asymmetric trap. The cloud is axially hydrodynamic, but due to the asymmetric trap radially collisionless. By locally heating the cloud we excite a thermal dipole mode and measure its oscillation frequency and damping rate. We find an unexpectedly large heat conduction compared to the homogeneous case. The enhanced heat conduction in this regime is partially caused by atoms with a high angular momentum spiraling in trajectories around the core of the cloud. Since atoms in these trajectories are almost collisionless they strongly contribute to the heat transfer. We observe a second, oscillating hydrodynamic mode, which we identify as a standing wave sound mode.Comment: Sumitted to Phys. Rev. Letters, 4 pages, 4 figure

The impact of recommendations and warnings on the quality evaluation of health websites: An online experiment

With the increase in availability of online health information (OHI), consumers need to be able to properly evaluate the quality of health websites. Although several established evaluation criteria for OHI are available, these are rarely used by consumers. To improve people's ability and motivation to critically evaluate OHI, insights into how these criteria can optimally be communicated are needed. This study aims to investigate whether educational messages recommending the use of quality criteria can improve consumers' ability to evaluate OHI credibility, especially among people with low health literacy. We also test whether these messages can yield a stronger effect when combined with information warning consumers against using non-established criteria. In an online experiment, we randomly assigned 403 participants to one of four conditions and asked them to evaluate two websites of different quality. The conditions consisted of recommendations promoting the use of established evaluation criteria, warnings against using commonly adopted non-established criteria, a combination of the two, and a control group. Participants exposed to messages recommending established criteria evaluated the credibility of the lower quality website as poorer, and were better able to discriminate between high and low quality information compared to those in the control group. A combination of recommendations and warnings also improved people's ability to evaluate, but did not yield a stronger effect than the recommendations alone. Subgroup analysis, however, showed that these effects existed only for those with high health literacy. We conclude that providing consumers with criteria to evaluate OHI might be a viable way to improve people's evaluation skills of online health materials. Further research is needed to identify efficient ways to communicate these criteria to low health literate audiences

Mindfulness in higher education: awareness and attention in university students increase during and after participation in a mindfulness curriculum course

This study assessed the effects of a mindfulness course in the curriculum of international students (n = 104) from 16 different countries at the University of Amsterdam. The curriculum consisted of seven weekly lectures, as well as studying scientific articles on mindfulness research and gaining some experiential learning in meditating. The primary goal of this course was not to become more mindful, but to learn about the origins and the applications of mindfulness in (child) psychiatry. Students filled in the Five Facet Mindfulness Questionnaire (FFMQ) at "wait-list," pre-course, post-course, and at 7 weeks follow-up. Multilevel analyses showed that mindful awareness decreased during wait-list (d = −0.11), increased from pre-course to post-course (d = 0.36), and even more so from pre-course to follow-up (d = 0.53). Differential effects for students from within and outside the Netherlands are discussed as well as for "meditator" versus "novice" students. International students and meditators showed an increase in mindfulness already during the course, whereas Dutch students and novices only reported an increase in mindfulness at follow-up. Overall, participation in a low-intensity mindfulness course in a university’s curriculum leads to an increased non-judgmental and non-reactive stance towards student’s thoughts, feelings, and emotions, during the course period, and their mindfulness increased even further after the course period. This increased mindfulness may help them in coping with stress given the pressure they are under and may improve their performance and their quality of life

Reaching the hydrodynamic regime in a Bose-Einstein condensate by suppression of avalanche

We report the realization of a Bose-Einstein condensate (BEC) in the hydrodynamic regime. The hydrodynamic regime is reached by evaporative cooling at a relative low density suppressing the effect of avalanches. With the suppression of avalanches a BEC containing 120.10^6 atoms is produced. The collisional opacity can be tuned from the collisionless regime to a collisional opacity of more than 3 by compressing the trap after condensation. In the collisional opaque regime a significant heating of the cloud at time scales shorter than half of the radial trap period is measured. This is direct proof that the BEC is hydrodynamic.Comment: Article submitted for Phys. Rev. Letters, 6 figure