Acoustic Measurements of the Stripe and the Bubble Quantum Hall Phases

We launch surface acoustic waves (SAW) along both the $$and the$$ directions of a Hall bar and measure the anisotropic conductivity in a high purity GaAs 2-D electron system in the Quantum Hall regime of the stripe and the bubble phases. In the anisotropic stripe phase, SAW propagating along the "easy" $$direction sense a compressible behavior (finite resistance) which is seen in standard transport measurement only if current flows along the "hard"$$ direction. In the isotropic bubble phase, the SAW data show compressible behavior in both directions, in marked contrast to the incompressible quantum Hall behavior seen in transport measurements. These results challenge models that assume that both the stripe and the bubble phase consist of incompressible domains and raise important questions about the role of domain boundaries in SAW propagation.Comment: Published version from New Journal of Physic

Scanning X-ray diffraction microscopy of a 6 GHz surface acoustic wave

Surface acoustic waves at frequencies beyond a few GHz are promising components for quantum technology applications. Applying scanning X-ray diffraction microcopy we directly map the locally resolved components of the three-dimensional strain field generated by a standing surface acoustic wave on GaAs with wavelength $\lambda\simeq500\,$nm corresponding to frequencies near 6 GHz. We find that the lattice distortions perpendicular to the surface are phase-shifted compared to those in propagation direction. Model calculations based on Rayleigh waves confirm our measurements. Our results represent a break through in providing a full characterization of a radio frequency surface acoustic wave beyond plain imaging.Comment: 9 pages, 6 figure

White Matter Injury and General Movements in High-Risk Preterm Infants

BACKGROUND AND PURPOSE: Very preterm infants (birth weight, MATERIALS AND METHODS: In this prospective study of 47 preterm infants of 24-30 weeks' gestation, brain MR imaging was performed at term-equivalent age. Infants underwent T1- and T2-weighted imaging for volumetric analysis and DTI. General movements were assessed at 10-15 weeks' postterm age, and neurodevelopmental outcomes were evaluated at 2 years by using the Bayley Scales of Infant and Toddler Development Ill. RESULTS: Nine infants had aberrant general movements and were more likely to have adverse neurodevelopmental outcomes, compared with infants with normal movements. In infants with aberrant movements, Tract-Based Spatial Statistics analysis identified significantly lower fractional anisotropy in widespread white matter tracts, including the corpus callosum, inferior longitudinal and fronto-occipital fasciculi, internal capsule, and optic radiation. The subset of infants having both aberrant movements and abnormal neurodevelopmental outcomes in cognitive, language, and motor skills had significantly lower fractional anisotropy in specific brain regions. CONCLUSIONS: Aberrant general movements at 10-15 weeks' postterm are associated with adverse neurodevelopmental outcomes and specific white matter microstructure abnormalities for cognitive, language, and motor delays

Summarizing activity limitations in children with chronic illnesses living in the community: a measurement study of scales using supplemented interRAI items

<p>Abstract</p> <p>Background</p> <p>To test the validity and reliability of scales intended to measure activity limitations faced by children with chronic illnesses living in the community. The scales were based on information provided by caregivers to service program personnel almost exclusively trained as social workers. The items used to measure activity limitations were interRAI items supplemented so that they were more applicable to activity limitations in children with chronic illnesses. In addition, these analyses may shed light on the possibility of gathering functional information that can span the life course as well as spanning different care settings.</p> <p>Methods</p> <p>Analyses included testing the internal consistency, predictive, concurrent, discriminant and construct validity of two activity limitation scales. The scales were developed using assessment data gathered in the United States of America (USA) from over 2,700 assessments of children aged 4 to 20 receiving Medicaid Early and Periodic Screening, Diagnostic and Treatment (EPSDT) services, specifically Personal Care Services to assist children in overcoming activity limitations. The Medicaid program in the USA pays for health care services provided to children in low-income households. Data were collected in a single, large state in the southwestern USA in late 2008 and early 2009. A similar sample of children was assessed in 2010, and the analyses were replicated using this sample.</p> <p>Results</p> <p>The two scales exhibited excellent internal consistency. Evidence on the concurrent, predictive, discriminant, and construct validity of the proposed scales was strong. Quite importantly, scale scores were not correlated with (confounded with) a child's developmental stage or age. The results for these scales and items were consistent across the two independent samples.</p> <p>Conclusions</p> <p>Unpaid caregivers, usually parents, can provide assessors lacking either medical or nursing training with reliable and valid information on the activity limitations of children. One can summarize these data in scales that are both internally consistent and valid. Researchers and clinicians can use supplemented interRAI items to provide guidance for professionals and programs serving children, as well as older persons. This research emphasizes the importance of developing medical information systems that allow one to integrate information not only across care settings but also across an individual's life course.</p

Maternal Fish Consumption and Infant Birth Size and Gestation: New York State Angler Cohort Study

BACKGROUND: The scientific literature poses a perplexing dilemma for pregnant women with respect to the consumption of fish from natural bodies of water. On one hand, fish is a good source of protein, low in fat and a rich source of other nutrients all of which have presumably beneficial effects on developing embryos and fetuses. On the other hand, consumption of fish contaminated with environmental toxicants such as polychlorinated biphenyls (PCBs) has been associated with decrements in gestation and birth size. METHODS: 2,716 infants born between 1986–1991 to participants of the New York State Angler Cohort Study were studied with respect to duration of maternal consumption of contaminated fish from Lake Ontario and its tributaries and gestation and birth size. Hospital delivery records (maternal and newborn) were obtained for 92% of infants for the ascertainment of gestation (weeks), birth size (weight, length, chest, and head circumference) and other known determinants of fetal growth (i.e., maternal parity, history of placental infarction, uterine bleeding, pregnancy loss or cigarette smoking and infant's race, sex and presence of birth defect). Duration of maternal fish consumption prior to the index infant's birth was categorized as: none; 1–2, 3–7, 8+ years, while birth weight (in grams), birth length (in centimeters), and head and chest circumference (in centimeters) were left as continuous variables in multiple linear regression models. Birth size percentiles, ponderal indices and head to chest circumference ratios were computed to further assess proportionality and birth size in relation to gestational age. RESULTS: Analysis of variance failed to identify significant mean differences in gestation or any measure of birth size in relation to duration of maternal lifetime fish consumption. Multiple linear regressions identified gestational age, male sex, number of daily cigarettes, parity and placental infarction, as significant determinants of birth size. CONCLUSIONS: The results support the absence of an adverse relation between Lake Ontario fish consumption and reduced birth size as measured by weight, length and head circumference. Biological determinants and maternal cigarette smoking during pregnancy remain important determinants of birth size

Day occupation is associated with psychopathology for adolescents and young adults with Down syndrome

Background: Young adults with Down syndrome experience increased rates of emotional and behavioural problems compared with the general population. Most adolescents with Down syndrome living in Western Australia participate in sheltered employment as their main day occupation. Relationship between day occupation and changes in behaviour has not been examined. Therefore, the aim of this research was to explore any relationship between post school day occupations and changes in the young person’s behaviour. Methods: The Down syndrome Needs Opinion Wishes database was used for case ascertainment of young adults aged 15 to 32 years with Down syndrome. Families of 118 young people in this population-based database completed questionnaires in 2004, 2009 and 2011. The questionnaires addressed both young person characteristics such as age, gender, presence of impairments, behaviour, functioning in activities of daily living, and family characteristics such as income and family functioning. Post-school day occupations in which the young people were participating included open and sheltered employment, training and day recreation programs. Change in behaviour of young adults who remained in the same post-school day occupation from 2009 to 2011 (n = 103) were examined in a linear regression model adjusting for confounding variables including age, gender, prior functioning and behaviour in 2004 and family income.Results: In comparison to those young adults attending open employment from 2009 to 2011, those attending day recreation programs were reported to experience worsening in behaviour both in the unadjusted (effect size -0.14, 95% CI -0.24, -0.05) and adjusted models (effect size -0.15, 95% CI -0.29, -0.01). Conclusions: We found that the behaviour of those participating in open employment improved compared to those attending other day occupations. Further examination of the direction of this association is required

Girls and Boys Born before 28 Weeks Gestation: Risks of Cognitive, Behavioral, and Neurologic Outcomes at Age 10 Years

To compare the prevalence of cognitive, neurological, and behavioral outcomes at 10 years of age in 428 girls and 446 boys who were born extremely preterm (EP)

Valid and reliable instruments for arm-hand assessment at ICF activity level in persons with hemiplegia: a systematic review

Contains fulltext : 110141.pdf (publisher's version ) (Open Access)BACKGROUND: Loss of arm-hand performance due to a hemiparesis as a result of stroke or cerebral palsy (CP), leads to large problems in daily life of these patients. Assessment of arm-hand performance is important in both clinical practice and research. To gain more insight in e.g. effectiveness of common therapies for different patient populations with similar clinical characteristics, consensus regarding the choice and use of outcome measures is paramount. To guide this choice, an overview of available instruments is necessary. The aim of this systematic review is to identify, evaluate and categorize instruments, reported to be valid and reliable, assessing arm-hand performance at the ICF activity level in patients with stroke or cerebral palsy. METHODS: A systematic literature search was performed to identify articles containing instruments assessing arm-hand skilled performance in patients with stroke or cerebral palsy. Instruments were identified and divided into the categories capacity, perceived performance and actual performance. A second search was performed to obtain information on their content and psychometrics. RESULTS: Regarding capacity, perceived performance and actual performance, 18, 9 and 3 instruments were included respectively. Only 3 of all included instruments were used and tested in both patient populations. The content of the instruments differed widely regarding the ICF levels measured, assessment of the amount of use versus the quality of use, the inclusion of unimanual and/or bimanual tasks and the inclusion of basic and/or extended tasks. CONCLUSIONS: Although many instruments assess capacity and perceived performance, a dearth exists of instruments assessing actual performance. In addition, instruments appropriate for more than one patient population are sparse. For actual performance, new instruments have to be developed, with specific focus on the usability in different patient populations and the assessment of quality of use as well as amount of use. Also, consensus about the choice and use of instruments within and across populations is needed

Elevated protein concentrations in newborn blood and the risks of autism spectrum disorder, and of social impairment, at age 10 years among infants born before the 28th week of gestation

Among the 1 of 10 children who are born preterm annually in the United States, 6% are born before the third trimester. Among children who survive birth before the 28th week of gestation, the risks of autism spectrum disorder (ASD) and non-autistic social impairment are severalfold higher than in the general population. We examined the relationship between top quartile inflammation-related protein concentrations among children born extremely preterm and ASD or, separately, a high score on the Social Responsiveness Scale (SRS total score ≥65) among those who did not meet ASD criteria, using information only from the subset of children whose DAS-II verbal or non-verbal IQ was ≥70, who were assessed for ASD, and who had proteins measured in blood collected on ≥2 days (N = 763). ASD (N = 36) assessed at age 10 years is associated with recurrent top quartile concentrations of inflammation-related proteins during the first post-natal month (e.g., SAA odds ratio (OR); 95% confidence interval (CI): 2.5; 1.2–5.3) and IL-6 (OR; 95% CI: 2.6; 1.03–6.4)). Top quartile concentrations of neurotrophic proteins appear to moderate the increased risk of ASD associated with repeated top quartile concentrations of inflammation-related proteins. High (top quartile) concentrations of SAA are associated with elevated risk of ASD (2.8; 1.2–6.7) when Ang-1 concentrations are below the top quartile, but not when Ang-1 concentrations are high (1.3; 0.3–5.8). Similarly, high concentrations of TNF-α are associated with heightened risk of SRS-defined social impairment (N = 130) (2.0; 1.1–3.8) when ANG-1 concentrations are not high, but not when ANG-1 concentrations are elevated (0.5; 0.1–4.2)