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One salient characteristic of twin studies and the related behavioral genetics paradigm is the requirement of a large sample size. Countries or regions that are large in size and highly populated are at an advantage when implementing twin studies. However, given the fascinating and promising results obtained from twin studies, many researchers based in smaller countries or regions may still want to conduct twin studies in order to address local and theoretical issues. In this article, we have outlined the development of twin studies in Hong Kong, one of the Special Administrative Regions of China. The historical development and design of the two major twin studies of language and reading development implemented within Hong Kong are discussed, providing insights to researchers who also aspire to conduct twin studies in small regions.
The present study examined Korean mothers’ literate mediation strategies and socioemotional supports for 84 4- and 5-year-old children as they wrote unfamiliar words, and the relation of these strategies and comments to Korean children's Hangul reading. The mother–child writing interactions were videotaped. Eight strategies of maternal literate mediation were subsequently identified and five socioemotional comments were coded. Mothers of 5-year-olds used a coda-focused (i.e., emphasis on the final consonant of a syllable) strategy more often than those of 4-year-olds. The maternal coda focus was uniquely associated with children's word reading over and above mothers’ education and children's age, grade, vocabulary, and writing skill. Maternal literate mediation focused on the consonant–vowel (CV) subsyllabic unit, which explained children's reading of CV Gulja (Korean written syllable). These results suggest that efficient maternal literate mediation strategies focus on salient psycholinguistic grain size of Korean language such as CV (body) and coda subsyllabic units. In addition, the two socioemotional categories of process and critical comments were uniquely associated with children's reading. Findings underscore the importance of Korean language and culture in mothers’ early scaffolding to facilitate children's literacy acquisition.
We investigated cognitive and metalinguistic correlates of Chinese word reading in children with L2 Chinese learning experience and compared these to those in L1 Chinese speaking children. In total, 102 third and fourth grade children were recruited for the study. We examined a range of Chinese and English word reading related cognitive and metalinguistic skills. Compared to the native Chinese speaking group (NCSS), the non-native Chinese speaking group (NNCS) only performed better in English vocabulary knowledge and English working memory. On Chinese word reading related skills the NNCS group performed significantly worse than the NCS group. Hierarchical regression analyses revealed that the unique correlates of Chinese word reading for both groups were Chinese vocabulary, working memory, lexical tone awareness, and orthographic skills. For the NNCS group only, visual skills were also unique correlates of word reading skills. The results suggest cognitive similarities and differences in reading among native and non-native Chinese speakers.
We considered the extent to which learning to read Chinese characters and Chinese words (operationally defined as composed of two or more characters) are different in the present study. Study 1 compared reading of the same characters in isolation and those in the context of known words for 63 Chinese third-year kindergarteners. Results showed that children performed significantly better on reading the same characters when embedded within words than when alone. Study 2 further examined the correlates of single-character reading and two-character word reading for 142 Chinese third-year kindergarteners. Despite a high correlation between character reading and word reading, unique correlates emerged. Orthographic awareness, rapid automatized naming, and Pinyin letter-name knowledge independently explained variance in both character and word reading; however, orthographic awareness explained unique variance in character reading even after statistically controlling for word reading. Whereas orthographic and Pinyin knowledge may be more strongly associated with character recognition, other skills may be more important for learning to read words. Character and word reading may constitute slightly different processes, with somewhat different educational implications for each.
The Fontan operation can create a stable circulation from childhood through early adulthood. However, the absence of a sub-pulmonary pumping chamber leads to a physiology in which exercise capacity is limited and decreases with age starting in adolescence. The limitation in exercise capacity is more pronounced at peak levels of exercise, but is still present during more modest levels of activity. The underlying causes of exercise impairment relate to both central cardiovascular factors (oxygen delivery) and peripheral factors (oxygen extraction). Interventions to improve cardiac preload and to improve lean muscle mass may help to improve exercise capacity and, perhaps, will alter the “natural history” of the progressive decline.
Longitudinal predictors of writing composition in Chinese and English written by the same 153 Hong Kong nine-year-old children were tested, and their production errors within the English essays across ten categories, focusing on punctuation, spelling, and grammar, were compared to errors made by ninety American nine-year-olds writing on the same topic. The correlation between quality of the compositions in Chinese and English was .53. In stepwise regression analyses examining early predictors at ages between five and nine years, tasks of speed or fluency were consistently uniquely associated with Chinese writing composition; measures of English vocabulary knowledge, word reading, or both were consistently uniquely associated with English writing quality. Compared to the American children, Chinese children's writing reflected significantly higher proportions of errors in all grammatical categories but did not differ in punctuation or spelling. Findings underscore both similarities and differences in writing at different levels across languages.
Examples from Chinese, Thai, and Finnish illustrate why researchers cannot always be confident about the precise nature of the word unit. Understanding ambiguities regarding where a word begins and ends, and how to model word recognition when many derivations of a word are possible, is essential for universal theories of reading applied to both developing and expert readers.
An in-depth exploration of the associations of two aspects of morphological awareness in Chinese—homophone awareness and lexical compounding awareness—to Chinese word reading and vocabulary knowledge was the primary focus of the present study. Among 154 9-year-old Hong Kong Chinese children, both lexical compounding and homophone awareness were significantly associated with word reading (r = .54 for compounding, r = .38 for homophones) and vocabulary knowledge (r = .41 for compounding, r = .53 for homophones). However, with autoregressors additionally statistically controlled, homophone awareness remained uniquely associated with vocabulary but not word reading; lexical compounding was uniquely associated with both word reading and vocabulary. Path analyses best illustrated this pattern. Both morphological awareness constructs are likely bidirectionally associated with word reading and vocabulary knowledge. However, homophone awareness is more centrally associated with vocabulary knowledge because it taps specific, existing morpheme knowledge. In contrast, lexical compounding requires structural understanding of one's language, which seems to be helpful for both learning to read and vocabulary acquisition in Chinese.
In the present study, morphological structure processing of Chinese compounds was explored using a visual priming lexical decision task among 21 Hong Kong college students. Two compounding structures were compared. The first type was the subordinate, in which one morpheme modifies the other (e.g., 籃 球 [laam4 kau4, basket-ball, basketball]), similar to most English compounds (e.g., a snowman is a man made of snow and toothpaste is a paste for teeth; the second morpheme is the “head,” modified morpheme). The second type was the coordinative, in which both morphemes contribute equally to the meaning of the word. An example in Chinese is 花 草 (faa1 cou2, flower grass, i.e., plant). There are virtually no examples of this type in English, but an approximate equivalent phrase might be in and out, in which neither in nor out is more important than the other in comprising the expression. For the subordinate Chinese compound words, the same structure in prime and target facilitated the semantic priming effect, whereas for coordinative Chinese compound words, the same structure across prime and target inhibited the semantic priming effect. Results suggest that lexical processing of Chinese compounds is influenced by compounding structure processing.
Results from long-term experimental trials suggest that similar yields and lower costs are possible with organic compared to conventional soybeans, but there is little information about the relative costs and returns of these systems on commercial farms. This study examines the profitability of commercial soybean production using a nationwide survey of soybean producers for 2006 that includes a targeted sample of organic growers. Treatment-effect models are specified to characterize adopters of the organic approach and to isolate the impact of organic choice on operating, operating and capital, and total economic costs of soybean production. Organic soybean producers tend to be younger, have less crop acreage, and are less likely to work off-farm than conventional producers. Organic soybean production costs range from about $1 to $6 per bushel higher than those for conventional soybeans due to both lower yields and higher per-acre costs, while the average organic price premium in 2006 was more than $9 per bushel. Long-term cropping systems data suggest significant returns to organic systems result from similar yields and lower costs than conventional systems, but the high returns to commercial organic production found in this study can only be attributed to the significant price premiums paid for organic soybeans. Average organic soybean price premiums have remained high since 2006 despite much higher conventional soybean prices as users of organic soybeans attempt to retain and attract more acreage. However, increases in conventional soybean prices and fuel prices reduce the incentive for planting organic soybeans by improving returns to conventional production and increasing the relative costs of organic production.
Cross-sectional research has demonstrated poorer function and health-related quality of life (HRQOL) in those with multiple sclerosis (MS) but less is known about change over time. The goals of this study were to measure change in HRQOL and identify factors associated with change.
HRQOL was assessed at baseline and annually over two subsequent years using the Multiple Sclerosis Quality of Life Inventory. Function was assessed using the Expanded Disability Status Scale (EDSS) and the Multiple Sclerosis Functional Composite. Annualized rate of change was calculated for all twenty outcomes. Mixed effects modeling (univariate followed by multivariate) was used to examine the associations among patient characteristics and the age- and sex-adjusted Physical Component Summary (PCS) and Mental Component Summary (MCS) at study initiation and over the two years of follow-up.
Of 300 participants, 288 (96%) provided at least one assessment and are included in this analysis. Although 14 of the 20 outcomes showed a mean decline, only two (SF-36 physical function, p=0.018 and the EDSS, p<0.001) were statistically significant. The SF-36 social function showed a significant improvement (p=0.031). Only two variables were significantly associated with a decreased rate of decline or improvement over two years, including being female (PCS, p=0.001) and use of visiting nurse services (MCS, p<0.001).
HRQOL is relatively stable over two years of follow-up, particularly for mentally-oriented outcomes. Further research with a longer period of follow-up is needed to provide additional insight into factors associated with change in HRQOL in patients with MS.
To express object transfer, Cantonese-speakers use a ‘ditransitive’ ([V–R–T] or [V–T–R] where V=Verb, T=Theme, R=Recipient), or a more complex prepositional/serial-verb (P/SV) construction. Clausal elements in Cantonese datives can be optional (resulting in ‘full’ versus ‘non-full’ forms) or appear in variant orders (full non-canonical and full canonical). We report on usage of dative constructions with the word bei2 ‘to give’ in 86 parents and 53 three-year-old children during conversations. The parents used more P/SV than ditransitive bei2-datives, and vice versa for the children. Both groups showed a similar usage pattern of optional elements and variant structures in their ditransitive and P/SV bei2-datives. The roles of multiple construction types, optional elements and variant structures in children's learning of bei2-dative constructions are described.
Understanding how words are created is potentially a key component to being able to learn and understand new vocabulary words. However, research on morphological awareness is relatively rare. In this study, over 660 preschool-aged children from three language groups (Cantonese, Mandarin, and Korean speakers) in which compounding morphology is highly prevalent were tested on their abilities to manipulate familiar morphemes to create novel compound words as well as on a variety of early language and reasoning measures twice over the span of 9 months to 1 year. With Time 1 vocabulary knowledge, phonological processing, and reasoning skills controlled, morphological awareness predicted unique variance in Time 2 vocabulary knowledge across languages. Across languages, vocabulary knowledge also predicted unique variance in subsequent morphological awareness, with Time 1 morphological awareness controlled. Findings underscore the bidirectional bootstrapping of morphological awareness and vocabulary acquisition for languages in which lexical compounding is prominent, and suggest that morphological awareness may be practically important in predicting and fostering children's early vocabulary learning.
Emergent literacy skills are “precursors of formal reading that have their origins early in the life of a child” (Whitehurst & Lonigan, 2001: 12). Reading, unlike spoken language, almost never develops in the absence of formal teaching (Adams, 1990; Stanovich, 2000). This is especially true for Chinese character recognition (Li & Rao, 2000). Whereas most readers of alphabets can eventually assimilate letter–phoneme correspondences, which are relatively regular, and use these correspondence rules to learn to read new words on their own, orthography–phonology correspondence rules in Chinese are much less reliable (e.g. Ho, Wong & Chan, 1999). Despite the fact that supportive teaching is necessary for reading acquisition, however, there is also strong evidence that children's cognitive abilities contribute to their reading development. Below, we first give an overview of environmental factors that may impact on Chinese children's reading development. We then review the cognitive abilities of Chinese children that have been demonstrated to predict very early reading skill.
Many aspects of the environment may affect early Chinese literacy development (Cheung & Ng, 2003). Here, we mention four of them. First, varying linguistic environments can affect literacy acquisition (Bialystok, 2001). Across Chinese societies, spoken Chinese languages are sometimes mutually unintelligible. However, formal written Chinese uniformly represents Mandarin Chinese. Thus, mapping oral to written Chinese may be more challenging for those whose native language is Cantonese as compared to Mandarin, for instance (Cheung & Ng, 2003).
Objectives: The Ross procedure is increasingly utilized in the treatment of aortic valvar disease in children and adolescents. Our purpose was to compare pre- and post-operative exercise state in this population. Methods: We included patients who underwent the Ross procedure at our institution between January, 1995, and December, 2003, and in whom we had performed pre- and post-operative exercise stress tests. We used a ramp bicycle protocol to measure consumption of oxygen and production of carbon dioxide. Cardiac output was estimated from effective pulmonary blood flow by the helium acetylene re-breathing technique. Results: We studied 26 patients, having a median age at surgery of 15.7 years, with a range from 7.5 to 24.1 years. The primary indication for surgery in two-thirds was combined aortic stenosis and insufficiency. Median time from the operation to the post-operative exercise stress test was 17.4 months, with a range from 6.7 to 30.2 months. There was a trend toward lower maximal consumption of oxygen after the procedure, at 36.3 plus or minus 7.6 millilitres per kilogram per minute (83.9% predicted) as opposed to 38.6 plus or minus 8.4 millilitres per kilogram per minute (88.5% predicted, p equal to 0.06). Patients after the procedure, however, had significantly increased adiposity, so that there was no difference in maximal consumption of oxygen indexed to ideal body weight before and after the operation. In 20 of the patients, aerobic capacity improved or was stable after the operation. There was no post-operative chronotropic impairment. Conclusions: In the majority of patients following the Ross procedure, exercise performance is stable and within the normal range of a healthy age and sex matched population, despite sedentary lifestyles and increased adiposity.
Tasks of speeded naming, phonological awareness, word identification, nonsense word repetition, and vocabulary, along with two measures of morphological awareness (morphological structure awareness and morpheme identification), were administered to 115 kindergartners and 105 second graders. In the combined sample, 48% of the variance in vocabulary knowledge was predicted by the phonological processing and reading variables. Morphological structure awareness and morpheme identification together predicted an additional unique 10% of variance in vocabulary knowledge, for a total of 58% of the variance explained; both measures of morphological awareness were uniquely associated with vocabulary knowledge. Results underscore the potential importance of different facets of morphological awareness, as distinct from phonological processing skills, for understanding variability in early vocabulary acquisition.
Psychosis associated with stimulant use is an increasing problem, but there is little research evidence about the nature of the problem and its management.
To critically review the literature on stimulant psychosis and sensitisation.
Systematic review of studies that have investigated stimulant use and psychosis in humans. The main outcome measures were increases in psychosis with stimulant use, and differences between stimulant users and non-users.
Fifty-four studies met the inclusion criteria. Experimental studies show that a single dose of a stimulant drug can produce a brief increase in psychosis ratings (a ‘response’) in 50–70% of participants with schizophrenia and preexisting acute psychotic symptoms, unaffected by the presence of antipsychotic medication. Those with schizophrenia who do not have acute psychotic symptoms respond, but less frequently (30%). There has been little research into the longer-term effects of use.
Compliance with antipsychotic medication by someone with schizophrenia will not prevent a relapse or worsening of psychotic symptoms if stimulants are used. Low-dose antipsychotic treatment may be beneficial in stimulant users, to prevent sensitisation.
Patients with relapsing remitting multiple sclerosis on the disease modifying therapy of glatiramer acetate may be experiencing an adverse reaction of lipoatrophy at the sites of their subcutaneous injections. The purpose of this study was to complete a full examination of the injection site areas for users of glatiramer acetate, and to examine the relationship between lipoatrophy and patient characteristics.
Glatiramer acetate users were identified by means of chart review. Over six months, during regular clinic appointments, assessment included a full examination of injection site areas including visual inspection and manual palpation. Additional patient and clinical characteristics were obtained by means of chart review and patient questioning.
Seventy-six patients had been or were current users of glatiramer acetate. Of these, 34 (45%) had evidence of lipoatrophy in at least one injection site area. All were female, and five had severe, nine had moderate and 20 had mild lipoatrophy. In some cases, lipoatrophy occurred within months of therapy initiation. Case reviews are included for five of the 34 patients, along with photographs of the lipoatrophy, a magnetic resonance image and comments on skin biopsies.
Prevalence of lipoatrophy was much higher than expected. Possible reasons for this adverse reaction are explored and suggested treatment recommendations are reviewed. Lipoatrophy can be very disfiguring and is thought to be permanent, and the psychological impact can be significant. It is, therefore, important that patients be aware of the possibility of lipoatrophy, be able to identify it and discontinue injecting in areas where it is identified.