25 research outputs found

    Risk factors for psychopathology in children with intellectual disability: A prospective longitudinal population-based study

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    Background: This study examined risk factors for the development of psychopathology in children with intellectual disability (ID) in the developmental, biological, family and social-ecological domains. Methods: A population sample of 968 children, aged 6-18, enrolled in special schools in the Netherlands for educable and trainable ID were assessed at Time 1. A random 58% were re-contacted about 1 year later, resulting in a sample of 474 at Time 2. Results: Psychopathology was highly consistent over 1 year. Risk factors jointly accounted for significant, but small, portions of the variance in development of psychopathology. Child physical symptoms, family dysfunction and previous parental mental health treatment reported at Time 1 were uniquely associated with new psychopathology at Time 2. Conclusions: Prevention and early intervention research to find ways to reduce the incidence of psychopathology, possibly targeting family functioning, appear important. © 2006 Blackwell Publishing Ltd

    Developmental course of psychopathology in youths with and without intellectual disabilities

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    Background: We aimed to describe similarities and differences in the developmental course of psychopathology between children with and without intellectual disabilities (ID). Method: Multilevel growth curve analysis was used to analyse the developmental course of psychopathology, using the Child Behavior Checklist (CBCL), in two longitudinal multiple-birth-cohort samples of 6- to 18-year-old children with ID (N=978) and without ID (N=2,047) using three repeated measurements across a 6-year period. Results: Children with ID showed a higher level of problem behaviours across all ages compared to children without ID. A significant difference between the samples in the developmental courses was found for Aggressive Behaviour and Attention Problems, where children with ID showed a significantly larger decrease. Gender differences in the development of psychopathology were similar in both samples, except for Social Problems where males with ID showed a larger decrease in problem behaviour across time than females with ID and males and females without ID. Conclusion: Results indicate that children with ID continue to show a greater risk for psychopathology compared to typically developing children, although this higher risk is less pronounced at age 18 than it is at age 6 for Aggressive Behaviour. Contrary to our expectations, the developmental course of psychopathology in children with ID was quite similar from age 6 to 18 compared to children without ID. The normative developmental trajectories of psychopathology in children with ID, presented here, can serve as a yardstick against which development of childhood psychopathology can be detected as deviant. © 2007 The Authors Journal compilation © 2007 Association for Child and Adolescent Mental Health

    Formação de ectomicorrizas por monocários e dicários de Pisolithus sp. e interações nutricionais em Eucalyptus grandis Formation of ectomycorrhizae by monokaryons and dikaryons of Pisolithus sp. and nutritional interactions in Eucalyptus grandis

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    A germinação de basidiósporos de Pisolithus spp. dá origem a monocários, caracterizados por possuírem um único núcleo haplóide por célula. No campo, o eucalipto associa-se a micélios dicarióticos de Pisolithus spp., não havendo relatos sobre a capacidade dos monocários em estabelecer a associação ectomicorrízica com a planta hospedeira nessas condições. Embora os monocários de Pisolithus sp. sejam capazes de formar a associação ectomicorrízica in vitro, nada se sabe sobre a capacidade dessas estirpes em promover a absorção de nutrientes e o crescimento do eucalipto. O objetivo deste trabalho foi estudar a formação de ectomicorrizas por isolados monocarióticos e dicarióticos de Pisolithus sp. em Eucalyptus grandis, sob condições de casa de vegetação, bem como investigar as relações entre o estabelecimento da associação e o crescimento e a absorção de P, Ca, Mg, K, Cu e Zn pelas plantas. Caracterizou-se, também, a produção de massa seca micelial e a absorção de nutrientes pelos isolados fúngicos in vitro. Os isolados monocarióticos e dicarióticos testados variaram na produção de massa seca micelial e na capacidade de absorção de nutrientes. Em geral, os monocários apresentaram maiores índices de eficiência de utilização de nutrientes do que os dicários. Todos os isolados monocarióticos e dicarióticos formaram ectomicorrizas típicas quando associados com E. grandis. A presença dos isolados fúngicos monocarióticos associados às raízes laterais resultou em aumento do diâmetro radial das células da epiderme radicular, característico das ectomicorrizas de eucalipto, indicando que os monocários, à semelhança dos dicários, são capazes de produzir reguladores de crescimento. As médias de percentagem de colonização das raízes pelos isolados monocarióticos e dicarióticos variaram de 12 a 76 %. A absorção de Ca, Mg e K foi estimulada de forma expressiva pela presença das ectomicorrizas, com aumentos de até 760 vezes, demonstrando a relevância dessa associação no suprimento desses macronutrientes, especialmente o Ca. Alguns isolados monocarióticos são tão eficientes quanto os dicários na colonização radicular e na absorção de nutrientes. A caracterização dos monocários de Pisolithus sp. é necessária para se estabelecer a seleção e o cruzamento dos isolados com características desejáveis, visando ao melhoramento genético e à maior eficiência da associação simbiótica. Este trabalho constitui o primeiro relato das interações nutricionais entre monocários de Pisolithus sp. e a planta hospedeira.<br>The germination of Pisolithus spp. basidiospores originates monokaryons, characterized by having a single haploid nucleus per cell. In the field, eucalypts are associated with dykaryons of Pisolithus spp., there being no reports on the capacity of monokaryons to establish the ectomycorrhizal association with the host plant under such conditions. Although Pisolithus spp. monokaryons have been shown to form ectomycorrhizas in vitro, there is no information on the ability of these strains to promote nutrient uptake and growth of eucalypts. The objective of this study was to investigate the formation of ectomycorrhizae by monokaryotic and dikaryotic isolates of Pisolithus sp. in Eucalyptus grandis under greenhouse conditions, and the relationships between the establishment of ectomycorrhizae and the host plant growth and uptake of P, Ca, Mg, K, Cu, and Zn. The fungal isolates were highly variable in dry mycelial mass production and in their ability to take up macro- and micronutrients. Generally, the nutrient use efficiency of monokaryons was higher than that of dikaryons. All tested monokaryotic and dikaryotic isolates were able to form typical ectomycorrhizae when associated with E. grandis. The presence of monokaryotic isolates associated with the lateral roots of E. grandis resulted in typical increases in the radial diameter of the root epidermal cells, characteristic of eucalypt ectomycorrhizae, indicating that monokaryons, similarly to dikaryons, are capable of producing growth regulator compounds. The mean root colonization percentage of the monokaryotic and dikaryotic isolates varied from 12 to 76 %. The Ca, K, and Mg uptake was highly stimulated by the presence of ectomycorrhizae, with up to 760-fold increases, suggesting that the association must play a significant role in supplying the host with these nutrients, especially Ca. Some monokaryotic isolates are as efficient as the dikaryons at promoting root colonization and nutrient uptake. The characterization of Pisolithus sp. monokaryons is a basic requirement for the selection and crossing of isolates with desirable traits, aiming at the genetic improvement of fungal strains and a higher efficiency of the ectomycorrhizal association. This is the first report on the nutritional interactions between Pisolithus sp. monokaryons and the host plant

    A systemic overreaction to years versus decades of warming in a subarctic grassland ecosystem

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    Temperature governs most biotic processes, yet we know little about how warming affects whole ecosystems. Here we examined the responses of 128 components of a subarctic grassland to either 5–8 or >50 years of soil warming. Warming of >50 years drove the ecosystem to a new steady state possessing a distinct biotic composition and reduced species richness, biomass and soil organic matter. However, the warmed state was preceded by an overreaction to warming, which was related to organism physiology and was evident after 5–8 years. Ignoring this overreaction yielded errors of >100% for 83 variables when predicting their responses to a realistic warming scenario of 1 °C over 50 years, although some, including soil carbon content, remained stable after 5–8 years. This study challenges long-term ecosystem predictions made from short-term observations, and provides a framework for characterization of ecosystem responses to sustained climate change
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