Prospective evaluation of a cognitive vulnerability-stress model for depression: the interaction of schema self-structures and negative life events.

This study tested the diathesis-stress component of Beck\u27s (1967) cognitive theory of depression. Initially, participants completed measures assessing cognitive organization of the self-schema and depressive symptoms. One year later, participants completed measures assessing cognitive organization of the self-schema, depressive symptoms, and negative life events. Hierarchical multiple regression analyses, controlling for initial depression, indicated that more tightly interconnected negative content was associated with greater elevations in depressive symptoms following the occurrence of life events. More diffusely interconnected positive content for interpersonal self-referent information also interacted with life events to predict depressive symptoms. Cognitive organization dimensions showed moderate to high stability across the follow-up, suggesting that they may be trait-like vulnerability factors. Implications for the cognitive vulnerability-stress model of depression are discussed

III-V Quantum Dot Lasers Epitaxially Grown on Si

Monolithic integration of semiconductor lasers on silicon platform is the ultimate solution for creating complex optoelectronic circuits, which is the key to chip-to-chip and system-to-system communications. The direct epitaxial integration of III-V semiconductor materials on Si or Ge is one of the most promising approaches for the fabrication of electrically pumped light sources on a Si platform, promising low-cost, high-yield and large-scale deployment of silicon photonics [1], [2]. However, monolithic integration technique faces significant challenges because of the large material dissimilarity between III-V and Group IV materials, such as lattice mismatch, thermal expansion coefficient differences, and polar versus nonpolar surfaces [2], [3]. These differences tend to produce various types of defects, such as, antiphase boundaries (APBs), threading dislocations (TDs), and microcracks, which all generate nonradiative recombination centers and dramatically undermine the promise of III-V materials. Recently, quantum dots (QDs) structure is becoming widely used in active layer in semiconductor lasers due to their advantages of low threshold current density and temperature insensitive operation [4], [5]. Also, QD structures have attracted increasing attention for the monolithic III-V/Si integration due to their enhanced tolerance to defects and special capability of filtering the APBs and threading dislocations [6], [7]. In this paper, we review our recent progress made in the direct growth of III-V QD lasers on Si substrates

InAs/GaAs Quantum-Dot Lasers Monolithically Grown on on-axis Silicon (001)

Inversion boundaries (IBs) are charged planer defects that arise from the growth of polar III-V materials on non-polar Si (001) substrate. This paper demonstrates a novel technique to achieve all-MBE grown, IB-free GaAs on on-axis Si (001) substrates by employing periodic Si single-atomicheight steps to re-distribute the nucleation of IBs and promote IB self-annihilation in the subsequent GaAs growth. Furthermore, an electronically pumped quantum-dot (QD) laser has been demonstrated on this IB-free GaAs/Si platform with a maximum operating temperature of 120 °C. These results could be a significant step towards the monolithic integration of III-V materials and devices with mature CMOS technology

Measuring Cognitive Errors: Initial Development of the Cognitive Distortions Scale (CDS)

The ability to assess and correct biases in thinking is central to cognitive-behavioral therapy. Although measures of cognitive distortions exist, no measure comprehensively assesses the cognitive errors that are typically cited in the literature. The development and initial validation of the Cognitive Distortions Scale (CDS), a questionnaire that measures the tendency to make 10 cognitive distortions (e.g., mindreading, catastrophizing, all-or-nothing thinking) as they occur in interpersonal and achievement domains, is described. Across two studies, undergraduate students (n = 318) completed the CDS and other clinically relevant measures. The CDS and its two subscales appear to exhibit good psychometric properties; however, a factor analysis supported the use of a one-factor solution. Additional analyses suggested that some errors occur more frequently in some domains than others and that some errors may have more clinical significance than others. Notwithstanding issues inherent in measuring cognitive errors, and study limitations, the CDS appears to be a promising new measure of cognitive distortion, with good research and clinical potential

A meta-analysis of CBT for pathological worry among clients with GAD.

Previous meta-analyses assessing the effectiveness of Cognitive Behavioural Therapy (CBT) for Generalized Anxiety Disorder (GAD) used general measures of anxiety to assess symptom severity and improvement (e.g., Hamilton Anxiety Ratings Scale or a composite measure of anxiety). While informative, these studies do not provide sufficient evidence as to whether CBT significantly reduces the cardinal symptom of GAD: pathological worry. The current meta-analysis employed stringent inclusion criteria to evaluate relevant outcome studies, including the use of the Penn State Worry Questionnaire as the main outcome variable. Results showed a large overall effect size (ES) that was moderated by age and modality of treatment. Specifically, the largest gains were found for younger adults and for individual treatment. Analyses also revealed overall maintenance of gains at 6- and 12-month follow-up. Clinical implications of different treatment packages are discussed, as well as potential explanations for the differential effectiveness of CBT

Distribution of multiband THz wireless signals over fiber

Terahertz wireless communication is receiving great interest from researchers and industries, thanks to the new spectral windows between 0.1 and 1 THz offering opportunities for ultra-high-data-rate wireless transmission. Wavelength division multiplexing for wireless-over-fiber is foreseen as an enabling technique to support connection between base stations and a central station. This paper reviews architectures for photonic distribution and generation of multiband signals for sub- THz wireless communications, giving rates up to 100 Gb/s (20 Gb/s per band) using the full spectrum between 220 GHz and 280 GHz for downlink wireless transmission, and 10 Gb/s for uplink using on-off keying

Integrated Photonics for Wireless and Satellite Applications

The concept of using Photonic Integrated Circuits for generation of tunable mm-wave signals for wireless and satellite communication application is presented. The paper outlines the requirements for frequency stabilization and power consumption of semiconductor lasers when implemented in terrestrial wireless and satellite communication applications

Electrically pumped continuous-wave O-band quantum-dot superluminescent diode on silicon

High-power, broadband quantum-dot (QD) superluminescent diodes (SLDs) are ideal light sources for optical coherence tomography (OCT) imaging systems but have previously mainly been fabricated on native GaAs- or InP-based substrates. Recently, significant progress has been made to emigrate QD SLDs from native substrates to silicon substrates. Here, we demonstrate electrically pumped continuous-wave InAs QD SLDs monolithically grown on silicon substrates with significantly improved performance thanks to the achievement of a low density of defects in the III-V epilayers. The fabricated narrow-ridge-waveguide device exhibits a maximum 3 dB bandwidth of 103 nm emission spectrum centered at the O-band together with a maximum single facet output power of 3.8 mW at room temperature. The silicon-based SLD has been assessed for application in an OCT system. Under optimized conditions, a predicted axial resolution of ∼5.3µm is achieved with a corresponding output power of 0.66 mW/facet