The hypothesis that native language (L1) proficiency promotes English acquisition and overall academic achievement, a key theoretical assumption underlying bilingual education, was tested using latent growth modeling of data from 899 limited-English-proficient (LEP) eighth graders who were followed for 12 years in the National Education Longitudinal Study (NELS:88/2000). A model in which L1 proficiency predicted English (L2) reading ability, which in turn predicted high school achievement and distal educational/occupational attainment, fit the data well for the full LEP sample and a Hispanic subsample.In Hispanics, the model explained 24.1%, 7.4%, 29.4%, and 46.3% of the variance in initial English reading level, English reading growth, high school achievement, and post-high school attainment, respectively. Model fit for an Asian subsample, however, was poor. Possible reasons for lack of group invariance include cultural differences in construct conceptualization, greater linguistic and cultural heterogeneity within the Asian subgroup, and cross-language transfer difficulties when L1 and L2 lack a shared alphabetic structure. At least for Hispanic LEP students, this study's results establish the theoretical foundation for exploring the effectiveness of specific educational interventions.
The effectiveness of various strategies for educating the growing U.S. population of English language leamers (ELLs) has attracted a great deal of controversy. Bilingual education theory posits that retention and continued development of native language (LI) skills facilitate academic achievement through two mediating mechanisms. First, LI proficiency promotes second language (L2) acquisition, which is required to succeed academically. Second, competence in the heritage language positively influences academic achievement by maintaining self-esteem. Both of these meditational chains were tested in a multivariate latent growth model of longitudinal data from the National Education Longitudinal Study (NELS:88/2000). LI proficiency was specified to predict distal math and science outcomes through its association with both L2 literacy and self-esteem. In tum, academic self-concept was hypothesized to mediate the self-esteem-academic achievement relation. Home and school characteristics were included as covariates. The full model exhibited excellent fit only in the Hispanic portion of the ELL sample. Consistent with the broader literature, ethnicity appears to serve as an important moderator of the way native language proficiency relates to self-perception, L2 acquisition, and math and science achievement.
The lack of control procedures inherent in most of the experiments conducted to assess the effectiveness of skin temperature biofeedback in the treatment of Raynaud's disease renders the results inconclusive. In this study, control groups and a double-blind approach are adopted. Thirty-six patients, carefully screened for a diagnosis of primary Raynaud's disease, were assigned to a skin temperature increase group (N = 12), to an EMG relaxation control group (N = 12), or to a notreatment control group (N = 12). All patients kept records of their symptoms for the duration of the study. Each subject in the two training groups received 20 sessions, the last 2 conducted under cold stress. data analysis according to original group assignment, as well as following regrouping of subjects according to several learning criteria, showed that while all patients reported a marked decrease in the number of vasospastic attacks, no significant differences were found among the three groups on the clinical measures used to assess symptomatic relief. The general improvement reported must therefore be attributed to nonspecific factors.
Overweight and obesity in children and adolescents have become a worldwide public health concern with an ever-increasing prevalence. An excessive accumulation of intraabdominal fat tissue increases the risk of developing insulin resistance, diabetes, and cardiovascular diseases in adulthood. Body composition has a role in metabolism regulation in children and adolescents with differences between genders and age groups. Until recently, Air Displacement Plethysmography and Dual-energy X-ray Absorptiometry (DXA) have been the most common techniques used to assess body composition in children.Ultrasound (US) is an accurate, readily available, and radiation-free technique to quantify intra-abdominal fat in adults, but its use in children has not yet been validated. Computed tomography (CT) is a reliable tool to assess body composition, but its use in children should be avoided due to the significant radiation burden.Quantitative Magnetic Resonance Imaging (qMRI) provides an accurate measurement of body composition, through the quantification of the visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and brown adipose tissue (BAT), as well as lean mass. Furthermore, qMRI provides other significant estimates such as the Proton Density Fat-Fraction of the fat tissue. This review article aims to briefly describe the state of art of the advanced imaging techniques to provide a quantitative assessment of body composition in children and adolescents.
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