Cognitive versus behavior therapy: processes of change in the treatment of obsessive-compulsive disorder

Background: Behavior therapy [exposure and response prevention (ERP)] and cognitive therapy (CT) have proven effective in the treatment of obsessive-compulsive disorder. Direct comparisons between these treatment modalities have exposed no differences in efficacy. However, very little research has been conducted into the differences between the change processes in ERP and CT. This investigation is a first attempt to study change by measuring scores on a weekly basis rather than at specific stages in the treatment and follow-up. Methods: We used the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) at weekly intervals to rate and compare the severity of the obsessions and compulsions of 61 completers of either CT or ERP. The aim was to ascertain whether the process of change in CT is different from the process of change in ERP. We expected that ERP would primarily affect behavior, thus reducing compulsions first, while CT would primarily affect thought, thus reducing obsessions first. Results: Firstly, no differences were found between ERP and CT with respect to the change process for obsessions and compulsions. Secondly, it emerged that changes in compulsions predicted all treatment effects better than changes in obsessions. Conclusions: These results suggest that reduction of compulsions is the process through which both ERP and CT affect change. Copyright © 2008 S. Karger AG

Degradation in PV encapsulant strength of attachment: An interlaboratory study towards a climate-specific test

Reduced strength of attachment of the encapsulant resulting from the outdoor environment, including ultraviolet (UV) radiation, may decrease photovoltaic (PV) module lifetime by enabling widespread corrosion of internal components. To date, few studies exist showing how the adhesion of PV components varies with environmental stress. We have conducted an interlaboratory experiment to provide an understanding that will be used to develop climatic specific module tests. Factors examined in the study included the UV light source (lamp type), temperature, and humidity to be proposed for use in accelerated aging tests. A poly (ethylene-co-vinyl acetate) (EVA) formulation often used in veteran PV installations was studied using a compressive shear test - to quantify the strength of attachment at the EVA/glass interface. Replicate laminated glass/polymer/glass coupon specimens were weathered at 12 institutions using a variety of indoor chambers or field aging. Shear strength, s hear strain, and toughness were measured using a mechanical load-frame for the compressive shear test, with subsequent optical imaging and electron microscopy of the separated surfaces

Degradation in PV encapsulation transmittance: An interlaboratory study towards a climate-specific test

Reduced optical transmittance of encapsulants resulting from ultraviolet (UV) degradation has frequently been identified as a cause of decreased PV module performance through the life of service in the field. The present module safety and qualification standards, however, apply short UV doses only capable of examining design robustness or "infant mortality" failures. Essential information that might be used to screen encapsulation through product lifetime remains unknown. For example, the relative efficacy of xenon-arc and UVA-340 fluorescent sources or the typical range of activation energy for degradation is not quantified. We have conducted an interlaboratory experiment to provide the understanding that will be used towards developing a climate-and configuration-specific (UV) weathering test. Five representative, known formulations of EVA were studied in addition to one TPU material. Replicate laminated silica/polymer/silica specimens are being examined at 14 institutions using a variety of indoor chambers (including Xenon, UVA-340, and metal-halide light sources) or field aging. The solar-weighted transmittance, yellowness index, and the UV cut-off wavelength, determined from the measured hemispherical transmittance, are examined to provide understanding and guidance for the UV light source (lamp type) and temperature used in accelerated UV aging tests