Some improved rice (Oryza sativa L.) cultivars such as the new plant type (NPT) lines of IRRI or Japanese indica 3 japonica cultivars can attach a greater density of spikelets, and hence have higher yield potential (YP); however, low grain ripening means that their higher YP is not fully used. Our objective was to clarify why their grain ripening is lower than in other cultivars, and whether low assimilate supply to grains or insufficient sink capability of spikelets restricts grain ripening in these cases. IR65564-44-2-2 (NPT) and Akenohoshi (indica 3 japonica) cultivars yield lower percentages of ripened grain (PRG) and have lower spikelet filling percentages (F%) than other cultivars in field trials. When plant density was halved during the grain-filling period (GFP) to improve plant dry-matter increase (DMI), PRG and F% in Akenohoshi increased, but scarcely changed in IR65564-44-2-2 and other cultivars. Inferior assimilate supply to YP limited the PRG in most cultivars due to close relationships between PRG or F% and DMI/YP; however, in IR65564-44-2-2 increased DMI/YP did not improve PRG and F%. Among the higher YP cultivars, F% in IR65564-44-2-2 started to decrease earlier with accumulated temperature. When panicles detached during the early GFP were cultured in a complete nutrient medium for 1 wk, F% in cultured Akenohoshi and IR65564-44-2-2 was significantly greater than that under field conditions. These results suggest that inferior assimilate supply is the main cause of lower grain ripening in Akenohoshi, whereas the earlier decrease in grain ripening, probably due to higher spikelet nonfertilization, is the factor responsible in IR65564-44-2-2.
Heritage language (HL) speakers have received scholarly attention in recent years as an interdisciplinary research theme, but relatively less attention has been paid to their demographics. Existing studies of HL speakers' demographics often focus on young children in areas of high immigrant concentration (i.e., California, Florida, and New York); no study has systematically investigated cross-regional and chronological demographic patterns of adult HL speakers. From the perspective of HLs as a national resource, such demographic data on adult HL speakers are useful to gauge the availability of a bilingual workforce and determine structures needed to support and develop a bilingual U.S. population. Using the Integrated Public User Microdata Series (Ruggles & Sobek, 1997), which is based on data from the U.S. Census and the American Community Survey, this study makes geographical and chronological comparisons among groups of adult HL speakers from 1980 to 2010. The data show major differences in the demographics of adult HL speakers in different regions. The analyses also reveal differences by language, specifically between the adult HL speakers of Spanish and other languages. Implications of these patterns are discussed.Keywords: heritage language; demographics HERITAGE LANGUAGE (HL) SPEAKERS HAVE drawn much scholarly attention in recent years as an interdisciplinary research theme among language educators, linguists, and policy makers. For language educators, understanding how to teach mixed classes with HL speakers and nonheritage second language learners in the classroom is a perennial issue. It is a challenge because these two groups of language learners have different instructional needs and goals for learning the target language. Unless the curriculum is specifically developed for HL speakers, their unique linguistic and instructional needs are often overlooked
This study analyzes the choices that heritage language (HL) learners make when enrolling in language courses at community colleges. Data from the Students and Instructors of Languages at Community Colleges (SILCC) Surveys, a nationwide survey with 1,756 students taking language courses at 101 community colleges across 33 states in the U.S., show that as many as 42.2% of community college students in modern language classrooms are identified as HL speakers. Surprisingly, more than half of these HL speakers are studying a language other than their own HL despite their prior linguistic knowledge, cultural familiarity, and familial ties with their HL. This paper evaluates a few possible explanations why a large proportion of HL speakers are opting to learn a new, third language. Building upon prior research and current data, we discuss differences in linguistic backgrounds, demographics, motivational attributes, and academic goals between HL learners studying their own HL and those studying a new language.
This study is concerned with native Japanese speakers' acquisition of English lexical causativity. In Japanese, a large number of verbs, including those not participating in the causative alternation in English (e.g., kieru/kesu "disappear/be disappeared" and todoku/todokeru "deliver/be delivered"), are lexically causative, in addition to the prototypical causative verbs such as aku/akeru "open" and ugoku/ugokasu "move". This asymmetric relationship forms a gap between the L1 and L2 and will cause overgeneralization errors in the L2 utterances. In this study, 44 native speakers of English and 60 Japanese ESL learners participated in the grammaticality judgment tasks in a series of experiments. The data show that the negative transfer exists in the inherently-directed motion verbs and verbs of disappearance, but it is conditioned by the frequency of verbs. The existence of frequency effect on verbs in the asymmetric relationship indicates that certain classes of verbs must be learned from the input.
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