Validity Evidence of the Spanish Version of the Mindful Attention Awareness Scale Using the Rasch Measurement Model.

The Mindful Attention Awareness Scale (MAAS) is the most cited instrument to measure dispositional mindfulness. However, some aspects of its validity are still under debate. We aimed to assess different sources of validity evidence (i.e., response processes, content, internal structure, reliability, and relations with external variables) of the MAAS scores in a sample of Spanish-speaking participants (N = 812) applying Rasch modeling. The items formed an essentially unidimensional structure, the item hierarchy was similar to that of previous comparable studies, the items were well targeted, and the ordering of persons along the construct was adequate. Moreover, measures were invariant across four age groups and three groups based on meditation practice, and correlated as expected with a variety of well-being variables. In sum, our findings supported the interpretation of MAAS scores as a measure of mindfulness in our sample of Spanish-speaking participants. Any other specific inference should be tested.

Reductions in experiential avoidance explain changes in anxiety, depression and well-being after a mindfulness and self-compassion (MSC) training.

OBJECTIVE: The mindfulness and self-compassion (MSC) protocol has shown efficacy in reducing mental illness symptoms and increasing well-being. However, little is known on how the positive outcomes are produced. This study explores how reductions in experiential avoidance following MSC training may explain changes in the participants' levels of anxiety, depression, and well-being. METHODS: The 8-week protocol-based MSC training was delivered to 50 participants, and pre- to post- intervention changes in anxiety, depression, and well-being were measured. A series of mediation models were conducted, with changes in self-compassion as predictor, changes in experiential avoidance as mediator, and changes in mental health and well-being as outcome variables. Point estimates and bootstrap-corrected 95% confidence intervals were calculated to analyse indirect effects through experiential avoidance, by means of structural equation modeling (SEM). RESULTS: Following MSC training, participants increased their levels of self-compassion, reduced experiential avoidance, and enhanced mental health (i.e., anxiety and depression symptoms) and well-being scores. Increases in self-compassion were associated with decreases in experiential avoidance, which in turn were connected with changes in anxiety, depression, and well-being from pre- to post-training. The indirect path through changes in experiential avoidance represented moderate to large proportions of the total effects of self-compassion change-scores on anxiety, depression, and well-being change-scores. CONCLUSIONS: Reducing experiential avoidance and increasing psychological flexibility may be a key effect of MSC training linked to improvements of the participants' mental health and well-being scores. Self-compassion practices could exert effects on anxiety, depression and well-being mainly through promoting reductions in experiential avoidance.

What Do Meta-Analyses Have to Say About the Efficacy of Neurofeedback Applied to Children With ADHD? Review of Previous Meta-Analyses and a New Meta-Analysis.

Objective: We reviewed previously published meta-analyses of neurofeedback applied to children with ADHD and conducted a new meta-analysis of randomized controlled trials (RCTs) that updates previous results and incorporates methodological modifications. Method: Searches were carried out through PubMed, Sage, PsycINFO, SpringerLink, and Psicodoc. We used Hedges' (adjusted) g and a random-effects model. To assess heterogeneity, Q and I2 were calculated. We performed different analyses depending on the control groups, ADHD symptoms, pre- and/or posttreament data used and symptom evaluator. Results: We reviewed seven meta-analyses, and 17 studies were incorporated into the meta-analysis. RCTs support the efficacy of neurofeedback applied to ADHD when most proximal evaluators assess symptoms. Neurofeedback significantly improves inattention symptoms when possibly blinded evaluators assess symptoms. The preliminary results suggest that stimulant medication is more effective than neurofeedback. Conclusion: New RCTs that establish links between ADHD symptom measurements, subjects' learning after neurofeedback, and neurophysiological measures could improve the quality of the conclusions.

Further insight into the photostability of the pyrene fluorophore in halogenated solvents.

Pyrene fluorophores of pyrene-functionalized CdSe quantum dots (QD@Py), as well as alkylpyrene and pyrene itself (Py), undergo fast degradation in aerated chloroform under ultraviolet-A (UV-A, 316<λ<400 nm) illumination. Steady-state fluorescence studies of irradiated chloroform solutions of QD@Py show formation of new bands, red-shifted compared to that of the pyrene moiety. Similar behaviour is observed for pyrene and the alkylpyrene system. Column chromatography of the pyrene photolysate in chloroform allowed us to isolate photoproducts arising from pyrene degradation, and to obtain information on the structure of the photoproducts responsible for the emission bands. The most predominant photoproducts were those originating from the reaction of pyrene with dichloromethyl radicals. The phototransformation of QD@Py and the alkylpyrene involves mainly detachment of the alkyl chain from the aromatic ring, induced also by dichloromethyl radicals, and oxidation of the alkyl chain at the benzylic position was detected as well. By contrast, these pyrene systems show a high photostability in aerated dichloromethane. Transient absorption measurements showed formation of both pyrene triplet and pyrene radical cation for all pyrene systems in these halogenated solvents. The yield of pyrene radical cations for Py is higher than for QD@Py and the alkylpyrene. In addition, pyrene radical cations were longer-lived in dichloromethane than in chloroform. The reason for the pyrene photostability in dichloromethane is the different reactivity of chloromethyl and dichloromethyl radicals towards pyrene and oxygen. These studies show that the use of dichloromethane can be a suitable alternative to chloroform when the good solubility properties of these halogenated solvents are needed to dissolve pyrene when this chromophore is used as a fluorescent probe.

Efficient ultraviolet-light energy dissipation by an aromatic ketone.

Experimental evidence on the efficiency of 2,2',4,4'-tetramethoxybenzil for UV-light energy dissipation is provided. This non-phenolic aromatic ketone has a low energy triplet which quickly decays to the ketone ground state, thus avoiding the generation of undesirable reactive species.