Only a few common variants in the sequence of the genome have been shown to impact cognitive traits. Here we demonstrate that polygenic scores of educational attainment predict specific aspects of childhood cognition, as measured with IQ. Recently, three sequence variants were shown to associate with educational attainment, a confluence phenotype of genetic and environmental factors contributing to academic success.
View Article and Find Full Text PDFIn a small fraction of patients with schizophrenia or autism, alleles of copy-number variants (CNVs) in their genomes are probably the strongest factors contributing to the pathogenesis of the disease. These CNVs may provide an entry point for investigations into the mechanisms of brain function and dysfunction alike. They are not fully penetrant and offer an opportunity to study their effects separate from that of manifest disease.
View Article and Find Full Text PDFPrimary Objectives: To assess long-term effects of early traumatic brain injury (TBI) on mental health, cognition, behaviour and adjustment and to identify prognostic factors.
Methods And Procedures: A 1-year nationwide cohort of all 0-19 year old Icelandic children and adolescents diagnosed with TBI in 1992-1993 (n = 550) received a questionnaire with clinical outcome scales and questions on TBI and socio-economic status (SES) by mail ∼16 years post-injury. A control group (n = 1232), newly selected from the National Registry, received the same questionnaire.
This article describes psychometric testing of an Icelandic adaptation of the Adult Reading History Questionnaire (ARHQ), designed to detect a history of reading difficulties indicative of dyslexia. Tested in a large and diverse sample of 2,187 adults, the Icelandic adaptation demonstrated internal consistency reliability (Cronbach's alpha = .92) and test-retest reliability (r = .
View Article and Find Full Text PDFPrimary Objectives: To examine the scope of paediatric traumatic brain injury (TBI) as a health concern and to identify prognostic factors for TBI-related sequelae.
Methods And Procedures: The study was prospective and nationwide. A questionnaire was sent to a study group (SG) of all 0-19 years old in Iceland, diagnosed ∼16 years earlier with TBI during a 1-year period, 1992-1993 (n = 550) and to a control group (CG) (n = 1232), selected from the National Register.
We present detailed characterization of a unique high-index-contrast integrated optical polymer waveguide platform where the index of the cladding material is closely matched to that of water. Single-mode waveguides designed to operate across a large part of the visible spectrum have been fabricated and waveguide properties, including mode size, bend loss and evanescent coupling have been modeled using effective-index approximation, finite-element and finite-difference time domain methods. Integrated components such as directional couplers for wavelength splitting and ring resonators for refractive-index or temperature sensing have been modeled, fabricated and characterized.
View Article and Find Full Text PDFThe controlled transport and delivery of dichloromethane through platinum mesh coated with dodecylbenzenesulfonate-doped polypyrrole is demonstrated upon in situ electrochemical redox switching. Droplets of dichloromethane were observed to pass freely through the mesh upon reduction of the polymer as a result of the release of the surfactant dopant into the dichloromethane and the change in the surface energy of the polymer. Planar and liquid-filled tube configurations are investigated.
View Article and Find Full Text PDFAims: To estimate the prognostic value of injury severity, location of event, and demographic parameters, for symptoms of pediatric traumatic head injury (THI) 4 years later.
Methods: Data were collected prospectively from Reykjavik City Hospital on all patients age 0-19 years, diagnosed with THI (n = 408) during one year. Information was collected on patient demographics, location of traumatic event, cause of injury, injury severity, and ICD-9 diagnosis.
Aims: To estimate differences in the incidence of recorded traumatic head injuries by gender, age, severity, and geographical area.
Methods: The study was prospective and nationwide. Data were collected from all hospitals, emergency units and healthcare centers in Iceland regarding all Icelandic children and adolescents 0-19 years old consecutively diagnosed with traumatic head injuries (N = 550) during a one-year period.
The incidence of head trauma (ICD9 850-854) among children in the Reykjavík area, aged 0-14 years, was studied over a 5-year period, 1987-1991, using hospital records. On average, 72 children with head trauma were admitted to hospital each year, indicating an annual incidence of 1.70 per 1000 population.
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