Production and processing asymmetries in the acquisition of tense morphology by sequential bilingual children

This study investigates the production and on-line processing of English tense morphemes by sequential bilingual (L2) Turkish-speaking children with more than three years of exposure to English. Thirty nine 6-9-year-old L2 children and 28 typically developing age-matched monolingual (L1) children were administered the production component for third person –s and past tense of the Test for Early Grammatical Impairment (Rice & Wexler, 1996) and participated in an on-line word-monitoring task involving grammatical and ungrammatical sentences with presence/omission of tense (third person –s, past tense -ed) and non-tense (progressive –ing, possessive ‘s) morphemes. The L2 children’s performance on the on-line task was compared to that of children with Specific Language Impairment (SLI) in Montgomery & Leonard (1998, 2006) to ascertain similarities and differences between the two populations. Results showed that the L2 children were sensitive to the ungrammaticality induced by the omission of tense morphemes, despite variable production. This reinforces the claim about intact underlying syntactic representations in child L2 acquisition despite non target-like production (Haznedar & Schwartz, 1997).

Deglaciation of the Caucasus Mountains, Russia/Georgia, in the 21st century observed with ASTER satellite imagery and aerial photograpy

Changes in the map area of 498 glaciers located on the Main Caucasus ridge (MCR) and on Mt. Elbrus in the Greater Caucasus Mountains (Russia and Georgia) were assessed using multispectral ASTER and panchromatic Landsat imagery with 15 m spatial resolution in 1999/2001 and 2010/2012. Changes in recession rates of glacier snouts between 1987–2001 and 2001–2010 were investigated using aerial photography and ASTER imagery for a sub-sample of 44 glaciers. In total, glacier area decreased by 4.7 ± 2.1% or 19.2 ± 8.7 km2 from 407.3 ± 5.4 km2 to 388.1 ± 5.2 km2. Glaciers located in the central and western MCR lost 13.4 ± 7.3 km2 (4.7 ± 2.5%) in total or 8.5 km2 (5.0 ± 2.4%) and 4.9 km2 (4.1 ± 2.7%) respectively. Glaciers on Mt. Elbrus, although located at higher elevations, lost 5.8 ± 1.4 km2 (4.9 ± 1.2%) of their total area. The recession rates of valley glacier termini increased between 1987–2000/01 and 2000/01–2010 (2000 for the western MCR and 2001 for the central MCR and Mt.~Elbrus) from 3.8 ± 0.8, 3.2 ± 0.9 and 8.3 ± 0.8 m yr−1 to 11.9 ± 1.1, 8.7 ± 1.1 and 14.1 ± 1.1 m yr−1 in the central and western MCR and on Mt. Elbrus respectively. The highest rate of increase in glacier termini retreat was registered on the southern slope of the central MCR where it has tripled. A positive trend in summer temperatures forced glacier recession, and strong positive temperature anomalies in 1998, 2006, and 2010 contributed to the enhanced loss of ice. An increase in accumulation season precipitation observed in the northern MCR since the mid-1980s has not compensated for the effects of summer warming while the negative precipitation anomalies, observed on the southern slope of the central MCR in the 1990s, resulted in stronger glacier wastage.