Severity of specific language impairment predicts delayed development in number skills

The extent to which mathematical development is dependent upon language is controversial. This longitudinal study investigates the role of language ability in children's development of number skills. Participants were 229 children with specific language impairment (SLI) who were assessed initially at age 7 and again 1 year later. All participants completed measures of psycholinguistic development (expressive and receptive), performance IQ, and the Basic Number Skills subtest of the British Ability Scales. Number skills data for this sample were compared with normative population data. Consistent with predictions that language impairment would impact on numerical development, average standard scores were more than 1 SD below the population mean at both ages. Although the children showed improvements in raw scores at the second wave of the study, the discrepancy between their scores and the population data nonetheless increased over time. Regression analyses showed that, after controlling for the effect of PIQ, language skills explained an additional 19 and 17% of the variance in number skills for ages 7 and 8, respectively. Furthermore, logistic regression analyses revealed that less improvement in the child's language ability over the course of the year was associated with a greater odds of a drop in performance in basic number skills from 7 to 8 years. The results are discussed in relation to the interaction of linguistic and cognitive factors in numerical development and the implications for mathematical education

Polarity reversal catalysis and enantioselective hydrogen-atom transfer

This thesis is divided into two sections: Section A Polarity reversal catalysis (PRC) is a method by which sluggish abstraction of electron deficient hydrogen by electrophilic radicals, such as t-butoxyl radical (But0.), can be accelerated. In this section of the thesis, the effect of PRC by amine-alkylborane complexes on hydrogen-atom transfer from ketones was studied. ESR spectroscopy was used to monitor the radical reaction products. t-Butyl methyl ether was found to be 30 times more reactive than acetone towards hydrogen-atom abstraction by But0. at 190 K, and this difference is attributed entirely to polar effects. In contrast, the highly-nucleophilic amine-boryl radical Me3N→BHThx abstracts hydrogen very much more rapidly from acetone than from the ether. Competitive abstraction from the two different types of α-C-H groups in methyl isopropyl ketone MeC(0)CHMe2 by amine-alkylboryl radicals which have differing steric demands has also been quantified. Specific alkyl radicals can be generated for ESR studies at low temperature by UV irradiation of a solution containing di-t-butyl peroxide, trimethylamine-butylborane, and the corresponding alkyl chloride. This procedure complements the "triethylsilane method" of Hudson and Jackson for alkyl radical generation from bromoalkanes. Section B This section describes the application of PRC to bring about enantioselective α-hydrogen-atom abstraction from esters of the type R1R2CHCO2R 3 using optically active amine-alkylboranes to catalyse the reaction of t-butoxyl radicals. This procedure has been used to bring about kinetic resolution of such esters. The bis(isopinocampheylborane) complex of N,N,N1,N1-tetramethyl- ethylenediamine and some of its derivatives were investigated as optically active polarity reversal catalysts. After partial consumption of the substrate, the amount remaining and its enantiomeric excess (ee) have been used to derive enantioselectivity constants (kR/S/kS/R) for α-hydrogen-atom abstraction from a variety of esters. Enantioselectivity is sensitive to the substituent bulk at the 2-position of the pinene moiety of the catalyst, and varies considerably with the structure of the substrate. The highest selectivity was observed for hydrogen abstraction from dimethyl 2,2-dimethyl-1,3-dioxolane-trans-dicarboxylate, when after 75% consumption of initially-racemic ester at 183 K, the residual substrate showed an ee of 97%. A transition state model is proposed to account for the observed enantioselectivities. In addition, ESR spectroscopy has been used, for the first time, to measure the relative rates of the elementary enantioselective hydrogen-atom abstraction reactions of optically active amine-boryl radicals

Core subjects at the end of primary school : identifying and explaining relative strengths of children with specific language impairment (SLI)

Background In general, children with specific language impairment (SLI) tend to fall behind their typically developing (TD) peers in educational attainment. Less is known about how children with SLI fare in particular areas of the curriculum and what predicts their levels of performance. Aims To compare the distributions of performance of children with SLI in three core school subjects (English, Mathematics and Science); to test the possibility that performance would vary across the core subjects; and to examine the extent to which language impairment predicts performance. Methods & Procedures This study was conducted in England and reports historical data on educational attainments. Teacher assessment and test scores of 176 eleven-year-old children with SLI were examined in the three core subjects and compared with known national norms. Possible predictors of performance were measured, including language ability at ages 7 and 11, educational placement type, and performance IQ. Outcomes & Results Children with SLI, compared with national norms, were found to be at a disadvantage in core school subjects. Nevertheless, some children attained the levels expected of TD peers. Performance was poorest in English; relative strengths were indicated in Science and, to a lesser extent, in Mathematics. Language skills were significant predictors of performance in all three core subjects. PIQ was the strongest predictor for Mathematics. For Science, both early language skills at 7 years and PIQ made significant contributions. Conclusions & Implications Language impacts on the school performance of children with SLI, but differentially across subjects. English for these children is the most challenging of the core subjects, reflecting the high levels of language demand it incurs. Science is an area of relative strength and mathematics appears to be intermediate, arguably because some tasks in these subjects can be performed with less reliance on verbal processing. Many children with SLI do have the potential to reach or exceed educational targets that are set at national levels for TD children

Conduct Problems Co-Occur with Hyperactivity in Children with Language Impairment : A Longitudinal Study from Childhood to Adolescence

Background: Language impairment (LI) is a common developmental disorder which is frequently associated with externalising problems. In this study, we investigate for the first time, joint trajectories of conduct problems and hyperactivity in children with LI from childhood to adolescence. We determine patterns of co-occurrence of symptoms and identify specific risk and protective factors. Methods: We develop a trajectory grouping method to examine simultaneously the conduct and hyperactivity problem scores of 164 children with LI at 7, 8, 11 and 16 years of age. Results: We identified five groups of children with distinct trajectories of symptoms. Three trajectory groups all had different conduct/hyperactivity problems: a persistent problems group (15%), an adolescent-onset group (24%) and a childhood-limited group (17%). There were two trajectory groups that did not show conduct problems. Conclusions: Conduct problems always co-occurred with hyperactivity in children with LI regardless of differences in the onset of symptoms (childhood versus adolescence) or their persistence (persistent versus childhood-limited). Reading difficulties were strongly associated with mixed conduct/hyperactivity problems that started early (childhood) and continued into adolescence (the persistent trajectory group). Prosocial behaviours were found to be protective against conduct problems

Self-harm risk between adolescence and midlife in people who experienced separation from one or both parents during childhood

AbstractBackgroundExperience of child-parent separation predicts adverse outcomes in later life. We conducted a detailed epidemiological examination of this complex relationship by modelling an array of separation scenarios and trajectories and subsequent risk of self-harm.MethodsThis cohort study examined persons born in Denmark during 1971–1997. We measured child-parent separations each year from birth to 15th birthday via complete residential address records in the Civil Registration System. Self-harm episodes between 15th birthday and early middle age were ascertained through linkage to psychiatric and general hospital registers. Incidence rate ratios (IRRs) from Poisson regression models were estimated against a reference category of individuals not separated from their parents.ResultsAll exposure models examined indicated an association with raised self-harm risk. For example, large elevations in risk were observed in relation to separation from both parents at 15th birthday (IRR 5.50, 95% CI 5.25–5.77), experiencing five or more changes in child-parent separation status (IRR 5.24, CI 4.88–5.63), and having a shorter duration of familial cohesion during upbringing. There was no significant evidence for varying strength of association according to child's gender.LimitationsMeasuring child-parent separation according to differential residential addresses took no account of the reason for or circumstances of these separations.ConclusionsThese novel findings suggest that self-harm prevention initiatives should be tailored toward exposed persons who remain psychologically distressed into adulthood. These high-risk subgroups include individuals with little experience of familial cohesion during their upbringing, those with the most complicated trajectories who lived through multiple child-parent separation transitions, and those separated from both parents during early adolescence

Do emotional difficulties and peer problems hew together from childhood to adolescence? The case of children with a history of developmental language disorder (DLD)

Children and adolescents with developmental language disorder (DLD) are, overall, vulnerable to difficulties in emotional adjustment and in peer relations. However, previous research has shown that different subgroups follow different trajectories in respect of quality of peer relations. Less is known of the trajectories of emotional development. We consider here the possibility that development in these two domains is interrelated: that is, the trajectories of emotional and peer problems will proceed in parallel. We conducted longitudinal joint trajectories analyses of emotional and peer relations in a sample of young people identified as having DLD at age 7 years and seen at intervals up to 16 years. Potential influences on joint trajectory group membership were examined. Findings revealed five distinct joint trajectories. Emotional and peer difficulties do hew together from childhood to adolescence for just over half of the sample, but not all. The variables most clearly associated with group membership were pragmatic language ability, prosociality and parental mental health. This is the first study to examine joint longitudinal trajectories of emotional and peer difficulties in individuals with DLD. We demonstrate that development in individuals with DLD is heterogeneous and identify three key variables associated with personal and social adjustment from childhood to adolescence. Theoretical and clinical implications of these findings are discussed

Health, employment and relationships: Correlates of personal wellbeing in young adults with and without a history of childhood language impairment

Objective: We examine the potential associations between self-rated health, employment situation, relationship status and personal wellbeing in young adults with and without a history of language impairment (LI). Methods: A total of 172 24-year-olds from the UK participated. Approximately half (N = 84) had a history of LI. Personal wellbeing was measured using ratings from three questions from the Office for National Statistics regarding life satisfaction, happiness and life being worthwhile. Results: There were similarities between individuals with a history of LI and their age-matched peers in self-rated personal wellbeing. However, regression analyses revealed self-rated health was the most consistent predictor of personal wellbeing for individuals with a history of LI in relation to life satisfaction (21% of variance), happiness (11%) and perceptions that things one does in life are worthwhile (32%). None of the regression analyses were significant for their peers. Conclusions: Similarities on ratings of wellbeing by young adults with and without a history of LI can mask heterogeneity and important differences. Young adults with a history of LI are more vulnerable to the effects of health, employment and relationship status on their wellbeing than their peers

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference