Surface-acoustic-wave counterflow micropumps for on-chip liquid motion control in two-dimensional microchannel arrays

Fully controlled liquid injection and flow in hydrophobic polydimethylsiloxane (PDMS) two-dimensional microchannel arrays based on on-chip integrated, low-voltage-driven micropumps are demonstrated. Our architecture exploits the surface-acoustic-wave (SAW) induced counterflow mechanism and the effect of nebulization anisotropies at crossing areas owing to lateral propagating SAWs. We show that by selectively exciting single or multiple SAWs, fluids can be drawn from their reservoirs and moved towards selected positions of a microchannel grid. Splitting of the main liquid flow is also demonstrated by exploiting multiple SAW beams. As a demonstrator, we show simultaneous filling of two orthogonal microchannels. The present results show that SAW micropumps are good candidates for truly integrated on-chip fluidic networks allowing liquid control in arbitrarily shaped two-dimensional microchannel arrays.

Whole-body motion discrimination in the visually impaired

Visually impaired people show superior abilities in various perception tasks such as auditory attention, auditory temporal resolution, auditory spatial tuning, and odor discrimination. However, with the use of psychophysical methods, auditory and olfactory detection thresholds typically do not differ between visually impaired and sighted participants. Using a motion platform we investigated thresholds of passive whole-body motion discrimination in nine visually impaired participants and nine age-matched sighted controls. Participants were rotated in yaw, tilted in roll, and translated along the y-axis at two different frequencies (0.3 Hz and 2 Hz). An adaptive 3-down 1-up staircase procedure was used along with a two-alternative direction (leftward vs. rightward) discrimination task. Superior performance of visually impaired participants was found in the 0.3 Hz roll tilt condition. No differences between the visually impaired and controls were observed in all other types of motion. The superior performance in the 0.3 Hz roll tilt condition could reflect differences in the integration of extra-vestibular cues and increased sensitivity towards changes in the direction of the gravito-inertial force. In the absence of visual information, roll tilts entail a more pronounced risk of falling, and this could eventually account for the group difference. It is argued that differences in experimental procedures (i.e. detection vs. discrimination of stimuli) explain the discrepant findings across perceptual tasks comparing blind and sighted participants.

Physical activity interventions in schools for improving lifestyle in European countries

Background: In the last decades, children’s and adolescents’ obesity and overweight have increased in European Countries. Unhealthy eating habits and sedentary lifestyle have been recognized to determine such an epidemic. Schools represent an ideal setting to modify harmful behaviors, and physical activity could be regarded as a potential way to avoid the metabolic risks related to obesity. Methods: A systematic review of the literature was carried out to summarize the evidence of school-based interventions aimed to promote, enhance and implement physical activity in European schools. Only randomized controlled trials were included, carried out in Europe from January 2000 to April 2014, universally delivered and targeting pupils aged between 3 and 18 years old. Results: Forty-seven studies were retrieved based either on multicomponent interventions or solely physical activity programs. Most aimed to prevent obesity and cardiovascular risks among youths. While few studies showed a decrease in BMI, positive results were achieved on other outcomes, such as metabolic parameters and physical fitness. Conclusion: Physical activity in schools should be regarded as a simple, non-expensive and enjoyable way to reach all the children and adolescents with adequate doses of moderate to vigorous physical activity.

Cathodal HD-tDCS on the right V5 improves motion perception in humans

Brain lesions in the visual associative cortex are known to impair visual perception, i.e., the capacity to correctly perceive different aspects of the visual world, such as motion, color, or shapes. Visual perception can be influenced by non-invasive brain stimulation such as transcranial direct current stimulation (tDCS). In a recently developed technique called high definition (HD) tDCS, small HD-electrodes are used instead of the sponge electrodes in the conventional approach. This is believed to achieve high focality and precision over the target area. In this paper we tested the effects of cathodal and anodal HD-tDCS over the right V5 on motion and shape perception in a single blind, within-subject, sham controlled, cross-over trial. The purpose of the study was to prove the high focality of the stimulation only over the target area. Twenty one healthy volunteers received 20 min of 2 mA cathodal, anodal and sham stimulation over the right V5 and their performance on a visual test was recorded. The results showed significant improvement in motion perception in the left hemifield after cathodal HD-tDCS, but not in shape perception. Sham and anodal HD-tDCS did not affect performance. The specific effect of influencing performance of visual tasks by modulating the excitability of the neurons in the visual cortex might be explained by the complexity of perceptual information needed for the tasks. This provokes a "noisy" activation state of the encoding neuronal patterns. We speculate that in this case cathodal HD-tDCS may focus the correct perception by decreasing global excitation and thus diminishing the "noise" below threshold.

Auditory motion direction encoding in auditory cortex and high-level visual cortex

The aim of this functional magnetic resonance imaging (fMRI) study was to identify human brain areas that are sensitive to the direction of auditory motion. Such directional sensitivity was assessed in a hypothesis-free manner by analyzing fMRI response patterns across the entire brain volume using a spherical-searchlight approach. In addition, we assessed directional sensitivity in three predefined brain areas that have been associated with auditory motion perception in previous neuroimaging studies. These were the primary auditory cortex, the planum temporale and the visual motion complex (hMT/V5+). Our whole-brain analysis revealed that the direction of sound-source movement could be decoded from fMRI response patterns in the right auditory cortex and in a high-level visual area located in the right lateral occipital cortex. Our region-of-interest-based analysis showed that the decoding of the direction of auditory motion was most reliable with activation patterns of the left and right planum temporale. Auditory motion direction could not be decoded from activation patterns in hMT/V5+. These findings provide further evidence for the planum temporale playing a central role in supporting auditory motion perception. In addition, our findings suggest a cross-modal transfer of directional information to high-level visual cortex in healthy humans.

Direction detection thresholds of passive self-motion in artistic gymnasts

In this study, we compared direction detection thresholds of passive self-motion in the dark between artistic gymnasts and controls. Twenty-four professional female artistic gymnasts (ranging from 7 to 20 years) and age-matched controls were seated on a motion platform and asked to discriminate the direction of angular (yaw, pitch, roll) and linear (leftward–rightward) motion. Gymnasts showed lower thresholds for the linear leftward–rightward motion. Interestingly, there was no difference for the angular motions. These results show that the outstanding self-motion abilities in artistic gymnasts are not related to an overall higher sensitivity in self-motion perception. With respect to vestibular processing, our results suggest that gymnastic expertise is exclusively linked to superior interpretation of otolith signals when no change in canal signals is present. In addition, thresholds were overall lower for the older (14–20 years) than for the younger (7–13 years) participants, indicating the maturation of vestibular sensitivity from childhood to adolescence.

Self-motion perception training: thresholds improve in the light but not in the dark

We investigated perceptual learning in self-motion perception. Blindfolded participants were displaced leftward or rightward by means of a motion platform and asked to indicate the direction of motion. A total of eleven participants underwent 3,360 practice trials, distributed over twelve (Experiment 1) or 6 days (Experiment 2). We found no improvement in motion discrimination in both experiments. These results are surprising since perceptual learning has been demonstrated for visual, auditory, and somatosensory discrimination. Improvements in the same task were found when visual input was provided (Experiment 3). The multisensory nature of vestibular information is discussed as a possible explanation of the absence of perceptual learning in darkness.

Subtile und direkte Mechanismen der sozialen Konstruktion von Geschlecht in Schulbüchern. Vorstellung eines Kategoriensystems zur Analyse der Geschlechter(un)gerechtigkeit von Texten und Bildern

Ausgehend von der Frauenbewegung in Deutschland wurden bereits vor über 40 Jahren erste Analysen zur Darstellung der Geschlechter in Schulbüchern vorgelegt. Sie haben gezeigt, dass weibliche Charaktere im Vergleich zu männlichen seltener und oft in geschlechterstereotypen Rollen dargestellt werden. Heute besteht auf gesellschaftlicher Ebene deutlich mehr Geschlechtergerechtigkeit, dennoch existieren nach wie vor subtile Formen von Diskriminierung in Schulbüchern. Der vorliegende Beitrag dokumentiert die Entwicklung eines Kategoriensystems, das geeignet ist, das Ausmaß von Geschlechter(un)gerechtigkeit in Texten und Bildern aus aktuell in deutschen Schulen verwendeten Deutsch- und Mathematikbüchern zu analysieren. Neben den Häufigkeiten der Darstellungen von weiblichen und männlichen Charakteren und der Geschlechtstypizität ihrer Rollen und Aktivitäten können hiermit zwei subtile Mechanismen der Herstellung von Geschlechterungleichheiten untersucht werden: geschlechter(un)gerechte Sprache und die räumliche Darstellung weiblicher und männlicher Charaktere. Erste Ergebnisse der Anwendung des Kategoriensystems für Deutsch- und Mathematikbücher werden in der Diskussion dargestellt.