The effect of learning context on L2 listening development

Little research has been done on the effect of learning context on L2 listening development. Motivated by DeKeyser’s (2015) skill acquisition theory of second language acquisition, this study compares L2 listening development in study abroad (SA) and at home (AH) contexts from both language knowledge and processing perspectives. One hundred forty-nine Chinese postgraduates studying in either China or the United Kingdom participated in a battery of listening tasks at the beginning and at the end of an academic year. These tasks measure auditory vocabulary knowledge and listening processing efficiency (i.e., accuracy, speed, and stability of processing) in word recognition, grammatical processing, and semantic analysis. Results show that, provided equal starting levels, the SA learners made more progress than the AH learners in speed of processing across the language processing tasks, with less clear results for vocabulary acquisition. Studying abroad may be an effective intervention for L2 learning, especially in terms of processing speed

Козацькі шаблі в колекції Переяславського Державного історичного музею

Стаття продовжує серію авторських досліджень з проблем історичного зброєзнавства, що вводять до наукового обігу нові, досі не оприлюднені речові джерела – козацькі шаблі XVII – XVIII ст. з найбільших музейних колекцій України. В основі опису реалізована власна ідея передачі головних характерних ознак січної зброї за всіма її параметрами.The article continues a series of author’s researches in the field of historical arms studies, which bring into scientific use new, undisclosed material sources – sabers of the 17-19 centuries from the biggest museum collections of Ukraine. On a basis of the description the author developed his own idea of conveying the basic characteristic attributes of a cold steel for all its parameters

Comparison of fluorescence-based techniques for the quantification of particle-induced hydroxyl radicals

<p>Abstract</p> <p>Background</p> <p>Reactive oxygen species including hydroxyl radicals can cause oxidative stress and mutations. Inhaled particulate matter can trigger formation of hydroxyl radicals, which have been implicated as one of the causes of particulate-induced lung disease. The extreme reactivity of hydroxyl radicals presents challenges to their detection and quantification. Here, three fluorescein derivatives [aminophenyl fluorescamine (APF), amplex ultrared, and dichlorofluorescein (DCFH)] and two radical species, proxyl fluorescamine and tempo-9-ac have been compared for their usefulness to measure hydroxyl radicals generated in two different systems: a solution containing ferrous iron and a suspension of pyrite particles.</p> <p>Results</p> <p>APF, amplex ultrared, and DCFH react similarly to the presence of hydroxyl radicals. Proxyl fluorescamine and tempo-9-ac do not react with hydroxyl radicals directly, which reduces their sensitivity. Since both DCFH and amplex ultrared will react with reactive oxygen species other than hydroxyl radicals and another highly reactive species, peroxynitite, they lack specificity.</p> <p>Conclusion</p> <p>The most useful probe evaluated here for hydroxyl radicals formed from cell-free particle suspensions is APF due to its sensitivity and selectivity.</p