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

Radial-Velocity and Light Variations of IR Cephei

Radical-velocity observations of the short-period Cepheid, IR Cephei, have been used to derive a complete radial-velocity versus phase curve for the variable, to investigate the presence of a possible binary companion, and to address the question of its membership in the Cepheus OB2 association. The observations are consistent with the absence of a close binary companion and shed doubt on its membership in the association. Photoelectric observations made with the Phoenix 10 Automated Photometric Telescope confirm the single nature of the star. We present simulations to show the effects of an equiluminous companion on the light curve of a Cepheid, concluding that the light curve of IR Cephei, whether or not it is corrected for a possible companion, exhibits the low-amplitude, sinusoidal variations characteristic of an s-type Cepheid

Electronically synthesized Nyquist pulses for photonic sampling of microwave signals

We report electronic generation of optical Nyquist pulses using an arbitrary waveform generator (AWG) followed by a Mach Zehnder modulator (MZM), providing a simple, highly stable and flexible technique to perform photonic sampling. Here, we demonstrate the generation of 10 GHz periodic optical Nyquist pulses by synthesizing both all-positive and alternate positive-negative electrical pulse trains using a 25 GHz bandwidth AWG. Biasing the MZM at null ensures the meeting of the Nyquist ISI-free criterion in the optical domain and allows for pulse compression. Moreover, we report the first photonic sampling and demodulation of 1 Gbaud 16- and 32-QAM signals up to 22.5 GHz using 10 GHz optical Nyquist sampling pulse trains

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

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

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

Photonic Sampling of Broadband Qam Microwave Signals Exploiting Interleaved Optical Nyquist Pulses

We performed photonic sampling of 6 Gbaud 16-QAM signals at 20 GHz sampling frequency by interleaving and time-aligning two 10 GHz Nyquist optical sampling pulse trains using a SMF as the dispersive medium

New Rotation Periods in the Pleiades: Interpreting Activity Indicators

We present results of photometric monitoring campaigns of G, K and M dwarfs in the Pleiades carried out in 1994, 1995 and 1996. We have determined rotation periods for 18 stars in this cluster. In this paper, we examine the validity of using observables such as X-ray activity and amplitude of photometric variations as indicators of angular momentum loss. We report the discovery of cool, slow rotators with high amplitudes of variation. This contradicts previous conclusions about the use of amplitudes as an alternate diagnostic of the saturation of angular momentum loss. We show that the X-ray data can be used as observational indicators of mass-dependent saturation in the angular momentum loss proposed on theoretical grounds

The Young Solar Analogs Project. I. Spectroscopic and Photometric Methods and Multi-year Timescale Spectroscopic Results

This is the first in a series of papers presenting methods and results from the Young Solar Analogs Project, which began in 2007. This project monitors both spectroscopically and photometrically a set of 31 young (300–1500 Myr) solar-type stars with the goal of gaining insight into the space environment of the Earth during the period when life first appeared. From our spectroscopic observations we derive the Mount Wilson S chromospheric activity index (SMW), and describe the method we use to transform our instrumental indices to SMW without the need for a color term. We introduce three photospheric indices based on strong absorption features in the blue-violet spectrum—the G-band, the Ca i resonance line, and the Hydrogen-γ line—with the expectation that these indices might prove to be useful in detecting variations in the surface temperatures of active solar-type stars. We also describe our photometric program, and in particular our Superstar technique for differential photometry which, instead of relying on a handful of comparison stars, uses the photon flux in the entire star field in the CCD image to derive the program star magnitude. This enables photometric errors on the order of 0.005–0.007 magnitude. We present time series plots of our spectroscopic data for all four indices, and carry out extensive statistical tests on those time series demonstrating the reality of variations on timescales of years in all four indices. We also statistically test for and discover correlations and anti-correlations between the four indices. We discuss the physical basis of those correlations. As it turns out, the photospheric indices appear to be most strongly affected by emission in the Paschen continuum. We thus anticipate that these indices may prove to be useful proxies for monitoring emission in the ultraviolet Balmer continuum. Future papers in this series will discuss variability of the program stars on medium (days–months) and short (minutes to hours) timescales