Power properties if invariant tests for spatial autocorrelation in linear regression

This paper derives some exact power properties of tests for spatial autocorrelation in the context of a linear regression model. In particular, we characterize the circumstances in which the power vanishes as the autocorrelation increases, thus extending the work of Krämer (2005). More generally, the analysis in the paper sheds new light on how the power of tests for spatial autocorrelation is affected by the matrix of regressors and by the spatial structure. We mainly focus on the problem of residual spatial autocorrelation, in which case it is appropriate to restrict attention to the class of invariant tests, but we also consider the case when the autocorrelation is due to the presence of a spatially lagged dependent variable among the regressors. A numerical study aimed at assessing the practical relevance of the theoretical results is included

Non-testability of equal weights spatial dependence

We show that any invariant test for spatial autocorrelation in a spatial error or spatial lag model with equal weights matrix has power equal to size. This result holds under the assumption of an elliptical distribution. Under Gaussianity, we also show that any test whose power is larger than its size for at least one point in the parameter space must be biased.

Infant-mother attachment and the growth of externalizing problems across the primary-school years

Background:  Some contend that attachment insecurity increases risk for the development of externalizing behavior problems in children. Method:  Latent-growth curve analyses were applied to data on 1,364 children from the NICHD Study of Early Child Care to evaluate the association between early attachment and teacher-rated externalizing problems across the primary-school years. Results:  Findings indicate that (a) both avoidant and disorganized attachment predict higher levels of externalizing problems but (b) that effects of disorganized attachment are moderated by family cumulative contextual risk, child gender and child age, with disorganized boys from risky social contexts manifesting increases in behavior problems over time. Conclusions:  These findings highlight the potentially conditional role of early attachment in children’s externalizing behavior problems and the need for further research evaluating causation and mediating mechanisms.

The effects of maternal postnatal depression and child sex on academic performance at age 16 years: a developmental approach

Background: Postnatal depression (PND) is associated with poor cognitive functioning in infancy and the early school years; long-term effects on academic outcome are not known. Method: Children of postnatally depressed (N = 50) and non-depressed mothers (N = 39), studied from infancy, were followed up at 16 years. We examined the effects on General Certificate of Secondary Education (GCSE) exam performance of maternal depression (postnatal and subsequent) and IQ, child sex and earlier cognitive development, and mother–child interactions, using structural equation modelling (SEM). Results: Boys, but not girls, of PND mothers had poorer GCSE results than control children. This was principally accounted for by effects on early child cognitive functioning, which showed strong continuity from infancy. PND had continuing negative effects on maternal interactions through childhood, and these also contributed to poorer GCSE performance. Neither chronic, nor recent, exposure to maternal depression had significant effects. Conclusions: The adverse effects of PND on male infants’ cognitive functioning may persist through development. Continuing difficulties in mother–child interactions are also important, suggesting that both early intervention and continuing monitoring of mothers with PND may be warranted.

Transatlantic spaces: production, location and style in 1960s-1970s action-adventure TV series

This paper argues that transatlantic hybridity connects space, visual style and ideological point of view in British television action-adventure fiction of the 1960s–1970s. It analyses the relationship between the physical location of TV series production at Elstree Studios, UK, the representation of place in programmes, and the international trade in television fiction between the UK and USA. The TV series made at Elstree by the ITC and ABC companies and their affiliates linked Britishness with an international modernity associated with the USA, while also promoting national specificity. To do this, they drew on film production techniques that were already common for TV series production in Hollywood. The British series made at Elstree adapted versions of US industrial organization and television formats, and made programmes expected to be saleable to US networks, on the basis of British experiences in TV co-production with US companies and of the international cinema and TV market.

Loss of language in early development of autism and specific language impairment

Background:  Several authors have highlighted areas of overlap in symptoms and impairment among children with autism spectrum disorder (ASD) and children with specific language impairment (SLI). By contrast, loss of language and broadly defined regression have been reported as relatively specific to autism. We compare the incidence of language loss and language progression of children with autism and SLI. Methods:  We used two complementary studies: the Special Needs and Autism Project (SNAP) and the Manchester Language Study (MLS) involving children with SLI. This yielded a combined sample of 368 children (305 males and 63 females) assessed in late childhood for autism, history of language loss, epilepsy, language abilities and nonverbal IQ. Results:  language loss occurred in just 1% of children with SLI but in 15% of children classified as having autism or autism spectrum disorder. Loss was more common among children with autism rather than milder ASD and is much less frequently reported when language development is delayed. For children who lost language skills before their first phrases, the phrased speech milestone was postponed but long-term language skills were not significantly lower than children with autism but without loss. For the few who experienced language loss after acquiring phrased speech, subsequent cognitive performance is more uncertain. Conclusions:  Language loss is highly specific to ASD. The underlying developmental abnormality may be more prevalent than raw data might suggest, its possible presence being hidden for children whose language development is delayed.

IQ in children with autism spectrum disorders: data from the Special Needs and Autism Project (SNAP)

Background Autism spectrum disorder (ASD) was once considered to be highly associated with intellectual disability and to show a characteristic IQ profile, with strengths in performance over verbal abilities and a distinctive pattern of ‘peaks’ and ‘troughs’ at the subtest level. However, there are few data from epidemiological studies. Method Comprehensive clinical assessments were conducted with 156 children aged 10–14 years [mean (s.d.)=11.7 (0.9)], seen as part of an epidemiological study (81 childhood autism, 75 other ASD). A sample weighting procedure enabled us to estimate characteristics of the total ASD population. Results Of the 75 children with ASD, 55% had an intellectual disability (IQ<70) but only 16% had moderate to severe intellectual disability (IQ<50); 28% had average intelligence (115>IQ>85) but only 3% were of above average intelligence (IQ>115). There was some evidence for a clinically significant Performance/Verbal IQ (PIQ/VIQ) discrepancy but discrepant verbal versus performance skills were not associated with a particular pattern of symptoms, as has been reported previously. There was mixed evidence of a characteristic subtest profile: whereas some previously reported patterns were supported (e.g. poor Comprehension), others were not (e.g. no ‘peak’ in Block Design). Adaptive skills were significantly lower than IQ and were associated with severity of early social impairment and also IQ. Conclusions In this epidemiological sample, ASD was less strongly associated with intellectual disability than traditionally held and there was only limited evidence of a distinctive IQ profile. Adaptive outcome was significantly impaired even for those children of average intelligence.

Working together? Parent and local authority views on the process of obtaining appropriate educational provision for children with autism spectrum disorders

Background: There is general agreement across all interested parties that a process of working together is the best way to determine which school or educational setting is right for an individual child with autism spectrum disorder. In the UK, families and local authorities both desire a constructive working relationship and see this as the best means by which to reach an agreement to determine where a child should be educated. It has been shown in published works 1 1. Batten and colleagues (Make schools make sense. Autism and education: the reality for families today; London: The National Autistic Society, 2006). View all notes that a constructive working relationship is not always achieved. Purpose: This small-scale study aims to explore the views of both parents and local authorities, focussing on how both parties perceive and experience the process of determining educational provision for children with autism spectrum disorders (ASD) within an English context. Sample, design and method: Parental opinion was gathered through the use of a questionnaire with closed and open responses. The questionnaire was distributed to two national charities, two local charities and 16 specialist schools, which offered the questionnaire to parents of children with ASD, resulting in an opportunity sample of 738 returned surveys. The views of local authority personnel from five local authorities were gathered through the use of semi-structured interviews. Data analyses included quantitative analysis of the closed response questionnaire items, and theme-based qualitative analysis of the open responses and interviews with local authority personnel. Results: In the majority of cases, parents in the survey obtained their first choice placement for their child. Despite this positive outcome, survey data indicated that parents found the process bureaucratic, stressful and time consuming. Parents tended to perceive alternative placement suggestions as financially motivated rather than in the best interests of the child. Interviews with local authority personnel showed an awareness of these concerns and the complex considerations involved in determining what is best for an individual child. Conclusions: This small-scale study highlights the need for more effective communication between parents of children with ASDs and local authority personnel at all stages of the process

The effect of cleft lip on socio-emotional functioning in school-aged children

Background: Children with cleft lip are known to be at raised risk for socio-emotional difficulties, but the nature of these problems and their causes are incompletely understood; longitudinal studies are required that include comprehensive assessment of child functioning, and consideration of developmental mechanisms. Method: Children with cleft lip (with and without cleft palate) (N = 93) and controls (N = 77), previously studied through infancy, were followed up at 7 years, and their socio-emotional functioning assessed using teacher and maternal reports, observations of social interactions, and child social representations (doll play). Direct and moderating effects of infant attachment and current parenting were investigated, as was the role of child communication difficulties and attractiveness. Results: Children with clefts had raised rates of teacher-reported social problems, and anxious and withdrawn-depressed behaviour; direct observations and child representations also revealed difficulties in social relationships. Child communication problems largely accounted for these effects, especially in children with cleft palate as well as cleft lip. Insecure attachment contributed to risk in both index and control groups, and a poorer current parenting environment exacerbated the difficulties of those with clefts. Conclusions: Children with clefts are at raised risk for socio-emotional difficulties in the school years; clinical interventions should focus on communication problems and supporting parenting; specific interventions around the transition to school may be required. More generally, the findings reflect the importance of communication skills for children’s peer relations.

The representation of fathers by children of depressed mothers: refining the meaning of parentification in high-risk samples

Background: Children’s representations of mothers in doll-play are associated with child adjustment. Despite the importance of fathers for children’s adjustment, especially in the context of maternal psychopathology, few studies have considered children’s representations of their fathers. Method: We examined the portrayal of fathers by 5-year-old children of depressed (N = 55) and non-depressed (N = 39) mothers in a doll-play procedure concerning family experience. Results: Children gave equal prominence in their play to mothers and fathers. Representations of fathers were unrelated to maternal mood, but were associated with parental conflict. Representations of child care for the father that was unreciprocated predicted poor child adjustment in school, but only in children exposed to maternal postnatal depression. Conclusions: It may be clinically useful to consider children’s distinctive representations of their mother and father; but the concept of parentification in relation to risk and resilience effects requires refinement.

Progressive erosion of genetic and epigenetic variation in callus-derived cocoa (Theobroma cacao) plants

Relatively little is known about the timing of genetic and epigenetic forms of somaclonal variation arising from callus growth. We surveyed for both types of change in cocoa (Theobroma cacao) plants regenerated from calli of various ages, and also between tissues from the source trees. For genetic change, we used 15 single sequence repeat (SSR) markers from four source trees and from 233 regenerated plants. For epigenetic change, we used 386 methylation-sensitive amplified polymorphism (MSAP) markers on leaf and explant (staminode) DNA from two source trees and on leaf DNA from 114 regenerants. Genetic variation within source trees was limited to one slippage mutation in one leaf. Regenerants were far more variable, with 35% exhibiting at least one mutation. Genetic variation initially accumulated with culture age but subsequently declined. MSAP (epigenetic) profiles diverged between leaf and staminode samples from source trees. Multivariate analysis revealed that leaves from regenerants occupied intermediate eigenspace between leaves and staminodes of source plants but became progressively more similar to source tree leaves with culture age. Statistical analysis confirmed this rather counterintuitive finding that leaves of ‘late regenerants’ exhibited significantly less genetic and epigenetic divergence from source leaves than those exposed to short periods of callus growth.

Characterisation of soils containing naturally occurring radioactive material (NORM) using in situ and rapid laboratory techniques. Case study: South Terras, Cornwall

In situ analysis has become increasingly important for contaminated land investigation and remediation. At present, portable techniques are used mainly as scanning tools to assess the spread and magnitude of the contamination, and are an adjunct to conventional laboratory analyses. A site in Cornwall, containing naturally occurring radioactive material (NORM), provided an opportunity for Reading University PhD student Anna Kutner to compare analytical data collected in situ with data generated by laboratory-based methods. The preliminary results in this paper extend the author‟s poster presentation at last September‟s GeoSpec2010 conference held in Lancaster.