Effect of language experience on selective auditory attention: An event-related potential study

Dual language experience has typically been shown to improve various executive control functions. We investigated with event-related brain potentials (ERPs) recorded from early (natively) bilingual speakers and control participants whether it also affects auditory selective attention. We delivered to our participants two tone streams, one to the left and one to the right ear. Both streams consisted of standard tones and two types of infrequent deviant tones which had either an enhanced duration or intensity. The participants were instructed to attend either to the right or left stream and to detect longer-duration deviants in the attended stream. The results showed that the early bilinguals did not outperform the controls in target detection accuracy or speed. However, the late portion of the attention-related ERP modulation (the negative difference, Nd) was larger over the left hemisphere in the early bilinguals than in the controls, suggesting that the maintenance of selective attention or further processing of selectively attended sounds is enhanced in the bilinguals. Moreover, the late reorienting negativity (RON) in response to intensity-deviant tones was larger in the bilinguals, suggesting more efficient disengagement of attention from distracting auditory events. Hence, our results demonstrate that brain responses associated with certain aspects of auditory attention are enhanced in the bilingual adults, indicating that early dual language exposure modulates the neuronal responsiveness of auditory modality.Peer reviewe

Saturation vapor pressure characterization of selected low-volatility organic compounds using a residence time chamber

Saturation vapor pressure (psat) is an important thermodynamic property regulating the gas-to-particle partitioning of organic compounds in the atmosphere. Low-volatility organic compounds (LVOCs), with sufficiently low psat values, primarily stay in the particle phase and contribute to aerosol formation. Obtaining accurate information on the psat of LVOCs requires volatility measurements performed at temperatures relevant to atmospheric aerosol formation. Here, we present an isothermal evaporation method using a residence time chamber to measure psat for dry single-compound nanoparticles at 295 K. Our method is able to characterize organic compounds with psat spanning from 10−8 to 10−4 Pa at 295 K. The compounds included four polyethylene glycols (PEGs: PEG6, PEG7, PEG8, and PEG9), two monocarboxylic acids (palmitic acid and stearic acid), two dicarboxylic acids (azelaic acid and sebacic acid), two alcohols (meso-erythritol and xylitol), and one ester (di-2-ethylhexyl sebacate). There was a good agreement between our measured psat values and those reported by previous volatility studies using different measurement techniques, mostly within 1 order of magnitude. Additionally, quantum-chemistry-based COSMOtherm calculations were performed to estimate the psat values of the studied compounds. COSMOtherm predicted the psat values for most of the studied compounds within 1 order of magnitude difference between the experimental and computational estimates.peerReviewe