Conceptual and socio-cognitive support for collaborative learning in videoconferencing environments

Studies have shown that videoconferences are an effective medium for facilitating communication between parties who are separated by distance. Furthermore, studies reveal that videoconferences are effective when used for distance learning, particularly when learners are engaged in complex collaborative learning tasks. However, as in face-to-face communication, learners benefit most when they receive additional support for such learning tasks. This article provides an overview of three empirical studies to illustrate more general insights regarding some of the more and less effective ways of supporting collaborative learning with videoconferencing. The focus is on conceptual support, such as structural visualization and socio-cognitive support, such as scripts. Based on the results of the three studies, conclusions can be drawn about the conceptual and socio-cognitive support measures that promote learning. Conclusions can also be reached about the need for employing both conceptual and socio-cognitive support to provide learners with the most benefit

Aluminum arsenide cleaved-edge overgrown quantum wires

We report conductance measurements in quantum wires made of aluminum arsenide, a heavy-mass, multi-valley one-dimensional (1D) system. Zero-bias conductance steps are observed as the electron density in the wire is lowered, with additional steps observable upon applying a finite dc bias. We attribute these steps to depopulation of successive 1D subbands. The quantum conductance is substantially reduced with respect to the anticipated value for a spin- and valley-degenerate 1D system. This reduction is consistent with disorder-induced, intra-wire backscattering which suppresses the transmission of 1D modes. Calculations are presented to demonstrate the role of strain in the 1D states of this cleaved-edge structure.Comment: Submitted to Applied Physics Letter

Oscillatory instabilities during formic acid oxidation on Pt(100), Pt(110) and Pt(111) under potentiostatic control. I. Experimental

The experimental characterization of the current/outer potential (I/U) behavior during the electrochemical CO oxidation on Pt(100), Pt(110) and Pt(111) is used as the first step towards a thorough investigation of the processes occurring during the electrochemical formic acid oxidation. The CO study is followed by new cyclovoltammetric results during the electrochemical formic acid oxidation on the corresponding Pt single crystals. At high concentrations of formic acid, the cyclovoltammograms revealed a splitting of the large current peak observed on the cathodic sweep into two peaks whose dependence on scan rate and reverse potential was investigated. It turned out that the presence of a sufficiently large ohmic resistance R was crucial for oscillatory instabilities. Given an appropriate resistance, all three Pt surfaces were found to exhibit current oscillations at both low and high formic acid concentrations. On Pt(100) stable mixed-mode oscillations were observed. In addition, the sensitivity of the oscillations to stirring was investigated. Whereas the period-1 oscillations were found to be independent of stirring, the mixed-mode oscillations transformed into simple oscillations with stirring. The mechanism giving rise to instability and oscillations is described

Distorted mental spatial representation of multi-level buildings - Humans are biased towards equilateral shapes of height and width

A distorted model of a familiar multi-level building with a systematic overestimation of the height was demonstrated earlier in psychophysical and real world navigational tasks. In the current study we further investigated this phenomenon with a tablet-based application. Participants were asked to adjust height and width of the presented buildings to best match their memory of the dimensional ratio. The estimation errors between adjusted and true height-width ratios were analyzed. Additionally, familiarity with respect to in- and outside of the building as well as demographic data were acquired. A total of 142 subjects aged 21 to 90 years from the cities of Bern and Munich were tested. Major results were: (1) a median overestimation of the height of the multi-level buildings of 11%;(2) estimation errors were significantly less if the particular building was unknown to participants;(3) in contrast, the height of tower-like buildings was underestimated;(4) the height of long, flat shaped buildings was overestimated. (5) Further features, such as the architectonical complexity were critical. Overall, our internal models of large multi-level buildings are distorted due to multiple factors including geometric features and memory effects demonstrating that such individual models are not rigid but plastic with consequences for spatial orientation and navigation

Mentoring as a Predominant Factor Affecting Well-Being of Older People

The authors of the paper studied the state of well-being of older people who retired and stop working at the company they have worked for over 20 years. The survey provided some useful insights into the problem with the reference to three samples of 10 older people from each group: 1) older people who retired and keep in touch with the previous organisation; 2) older people who retired and continue working at the company as consultants, supervisors, experts, mentors etc.; 3) older people who retired and work in another enterprise and lost the touch with the previous organisation. Retired people took part in present research by completing a questionnaire survey. A set of data was examined by being compared to reveal the state of older people’s well-being criteria predominance in the various sample groups

An Exact Conformal Symmetry Ansatz on Kaluza-Klein Reduced TMG

Using a Kaluza-Klein dimensional reduction, and further imposing a conformal Killing symmetry on the reduced metric generated by the dilaton, we show an Ansatz that yields many of the known stationary axisymmetric solutions to TMG.Comment: 20 pages, 1 figure, v3: postprint, added one re