Technology-based interventions for mental health in tertiary students: Systematic review

BACKGROUND: Mental disorders are responsible for a high level of disability burden in students attending university. However, many universities have limited resources available to support student mental health. Technology-based interventions may be highly relevant to university populations. Previous reviews have targeted substance use and eating disorders in tertiary students. However, the effectiveness of technology-based interventions for other mental disorders and related issues has not been reviewed. OBJECTIVE: To systematically review published randomized trials of technology-based interventions evaluated in a university setting for disorders other than substance use and eating disorders. METHODS: The PubMed, PsycInfo, and Cochrane Central Register of Controlled Trials databases were searched using keywords, phrases, and MeSH terms. Retrieved abstracts (n=1618) were double screened and coded. Included studies met the following criteria: (1) the study was a randomized trial or a randomized controlled trial, (2) the sample was composed of students attending a tertiary institution, (3) the intervention was delivered by or accessed using a technological device or process, (4) the age range of the sample was between 18 and 25 years, and (5) the intervention was designed to improve, reduce, or change symptoms relating to a mental disorder.RESULTS: A total of 27 studies met inclusion criteria for the present review. Most of the studies (24/27, 89%) employed interventions targeting anxiety symptoms or disorders or stress, although almost one-third (7/24, 29%) targeted both depression and anxiety. There were a total of 51 technology-based interventions employed across the 27 studies. Overall, approximately half (24/51, 47%) were associated with at least 1 significant positive outcome compared with the control at postintervention. However, 29% (15/51) failed to find a significant effect. Effect sizes were calculated for the 18 of 51 interventions that provided sufficient data. Median effect size was 0.54 (range -0.07 to 3.04) for 8 interventions targeting depression and anxiety symptoms and 0.84 (range -0.07 to 2.66) for 10 interventions targeting anxiety symptoms and disorders. Internet-based technology (typically involving cognitive behavioral therapy) was the most commonly employed medium, being employed in 16 of 27 studies and approximately half of the 51 technology-based interventions (25/51, 49%). Distal and universal preventive interventions were the most common type of intervention. Some methodological problems were evident in the studies, with randomization methods either inadequate or inadequately described, few studies specifying a primary outcome, and most of the studies failing to undertake or report appropriate intent-to-treat analyses. CONCLUSIONS: The findings of this review indicate that although technological interventions targeting certain mental health and related problems offer promise for students in university settings, more high quality trials that fully report randomization methods, outcome data, and data analysis methods are needed

Soil Microbial Networks Shift Across a High-Elevation Successional Gradient.

While it is well established that microbial composition and diversity shift along environmental gradients, how interactions among microbes change is poorly understood. Here, we tested how community structure and species interactions among diverse groups of soil microbes (bacteria, fungi, non-fungal eukaryotes) change across a fundamental ecological gradient, succession. Our study system is a high-elevation alpine ecosystem that exhibits variability in successional stage due to topography and harsh environmental conditions. We used hierarchical Bayesian joint distribution modeling to remove the influence of environmental covariates on species distributions and generated interaction networks using the residual species-to-species variance-covariance matrix. We hypothesized that as ecological succession proceeds, diversity will increase, species composition will change, and soil microbial networks will become more complex. As expected, we found that diversity of most taxonomic groups increased over succession, and species composition changed considerably. Interestingly, and contrary to our hypothesis, interaction networks became less complex over succession (fewer interactions per taxon). Interactions between photosynthetic microbes and any other organism became less frequent over the gradient, whereas interactions between plants or soil microfauna and any other organism were more abundant in late succession. Results demonstrate that patterns in diversity and composition do not necessarily relate to patterns in network complexity and suggest that network analyses provide new insight into the ecology of highly diverse, microscopic communities

Unusual conductance collapse in one-dimensional quantum structures

We report an unusual insulating state in one-dimensional quantum wires with a non-uniform confinement potential. The wires consist of a series of closely spaced split gates in high mobility GaAs/AlGaAs heterostructures. At certain combinations of wire widths, the conductance abruptly drops over three orders of magnitude, to zero on a linear scale. Two types of collapse are observed, one occurring in multi-subband wires in zero magnetic field and one in single subband wires in an in-plane field. The conductance of the wire in the collapse region is thermally activated with an energy of the order of 1 K. At low temperatures, the conductance shows a steep rise beyond a threshold DC source-drain voltage of order 1 mV, indicative of a gap in the density of states. Magnetic depopulation measurements show a decrease in the carrier density with lowering temperature. We discuss these results in the context of many-body effects such as charge density waves and Wigner crystallization in quantum wires.Comment: 5 pages, 5 eps figures, revte

Probing the Sensitivity of Electron Wave Interference to Disorder-Induced Scattering in Solid-State Devices

The study of electron motion in semiconductor billiards has elucidated our understanding of quantum interference and quantum chaos. The central assumption is that ionized donors generate only minor perturbations to the electron trajectories, which are determined by scattering from billiard walls. We use magnetoconductance fluctuations as a probe of the quantum interference and show that these fluctuations change radically when the scattering landscape is modified by thermally-induced charge displacement between donor sites. Our results challenge the accepted understanding of quantum interference effects in nanostructures.Comment: 8 pages, 5 figures, Submitted to Physical Review

Indistinguishable entangled photons generated by a light-emitting diode

A linear optical quantum computer relies on interference between photonic qubits for logic, and entanglement for near-deterministic operation. Here we measure the interference and entanglement properties of photons emitted by a quantum dot embedded within a light-emitting diode. We show that pairs of simultaneously generated photons are entangled, and indistinguishable from subsequently generated photons. We measure entanglement fidelity of 0.87 and two-photon-interference visibility of 0.60 ± 0.05. The visibility, limited by detector jitter, could be improved by optical cavity designs

Spin-incoherent transport in quantum wires

When a quantum wire is weakly confined, a conductance plateau appears at e(2)/h with decreasing carrier density in zero magnetic field accompanied by a gradual suppression of the 2e(2)/h plateau. Applying an in-plane magnetic field B-parallel to does not alter the value of this quantization; however, the e(2)/h plateau weakens with increasing B-parallel to up to 9 T, and then strengthens on further increasing B-parallel to, which also restores the 2e(2)/h plateau. Our results are consistent with spin-incoherent transport in a one-dimensional wire