Do fatty acids help in overcoming reading difficulties? A double-blind, placebo-controlled study of the effects of eicosapentaenoic acid and carnosine supplementation on children with dyslexia.

BACKGROUND: There are claims that dietary supplementation of unsaturated fatty acids could help children with dyslexia to overcome their reading problems. However, these claims have not yet been empirically tested. METHODS: This study was designed to test whether dietary supplementation was superior to placebo in treating reading, spelling or other reading-related skills of children with dyslexia. The experimental group (eicosapentaenoic acid, EPA, n = 30) ate dietary supplements and the control group (placebo, n = 31) placebos during the 90-day treatment period. The supplements contained omega-3 fatty acid (ethyl-EPA, 500 mg/day) and carnosine (400 mg/day). The groups were matched for reading skills, grade, gender, attention problems, intelligence and amount of special education. The literacy-related skills of the two groups were assessed before and after the treatment period. RESULTS: No group differences were observed between EPA and placebo in measures of reading accuracy or speed, spelling, decoding fluency, arithmetical skills, reading-related language skills, attention or behavioural problems. CONCLUSION: The present findings do not support the hypothesis that omega-3 fatty acid (ethyl-EPA) or carnosine has a role in the treatment of reading and spelling problems in children with dyslexia.

Reliability and validity of the Finnish version of the motor observation questionnaire for teachers.

OBJECTIVES: Observational screening instruments are often used as an effective, economical first step in the identification of children with Developmental Coordination Disorder (DCD). The aim was to investigate the psychometric properties of the Finnish version of the Motor Observation Questionnaire for Teachers (MOQ-T-FI). METHODS: The psychometric properties were tested using two separate samples (S1: age range 6-12, M 9y 5mo, females 101, males 92; S2: age range 6-9, M 7y 7mo, females 404, males 446). Teachers completed the MOQ-T-FI in both samples, and in sample 2 teachers' ratings were compared to student's performance on the Movement Assessment Battery for Children-Second Edition (MABC-2). Internal consistency was investigated by using Cronbach's alpha, predictive validity by receiver operating characteristic (ROC) analysis, concurrent validity by correlation analysis, and construct validity by factor analysis. RESULTS: The MOQ-T-FI behaves consistently with its original Dutch version. The internal consistency was excellent (α=0.97). The bifactor model, with one general factor and two specific factors, fit the data significantly better than the first-order model. The concurrent validity with the MABC-2 was moderate (r=0.37 p<0.001). Sensitivity was 82.5% and specificity 44.5%, respectively. CONCLUSION: Notwithstanding the low specificity the MOQ-T-FI can be considered as a promising screening tool in the school environment for Finnish children at risk of motor learning problems.

Gender differences in sexual behaviors and factors associated with nonuse of condoms among homeless and runaway youths.

Few studies have examined gender-specific factors associated with the nonuse of condoms among homeless and runaway youths (HRYs)-a population at high risk for HIV infection. In this article, we evaluate these factors and explore gender differences in background experiences, psychosocial functioning, and risk behaviors among HRYs from four U.S. metropolitan areas. Of 879 sexually active HRYs sampled, approximately 70% reported unprotected sexual intercourse during a 6-month period, and nearly a quarter reported never using condoms in the same period. Among males and females, having only one sex partner in the previous 6 months had the strongest association with nonuse of condoms. Among males, nonuse was also associated with having ever caused pregnancy, frequent marijuana use, prior physical victimization, and low self-control and sociability. Among females, nonuse was associated with knowledge of HIV status, prior sexual victimization, low social support, and infrequent marijuana use. These findings highlight the ongoing need for HIV prevention services for HRYs. Implications for the scope and content of these services are discussed.

Programmable optical interconnections by multilevel synthetic acousto-optic holograms.

Reconfigurable high-fidelity, high-efficiency weighted optical interconnection patterns are demonstrated for the first time to our knowledge with the aid of optimized multilevel phase gratings achieved electronically as phase-modulated sinusoidal refractive-index variations propagating in an acousto-optic Bragg cell.

Three-dimensionally modulated graded-index diffractive elements by thermal ion exchange in glass.

Thermal ion exchange was introduced recently [Appl. Phys. Lett. 66, 917 (1995)] as a method to generate graded refractive-index distributions that permit continuous one-dimensional phase modulation in diffractive optics. We apply enhanced diffusion-modeling techniques and a novel three-step optimization procedure to design, for the first time to our knowledge, efficient three-dimensional graded-index profiles with two-dimensional phase-modulation capability. A discrete, nonseparable inversion-symmetric signal pattern is demonstrated experimentally in which the uniformity error in the intensities of the seven signal spots is less than 5%.

Binary surface-relief gratings for array illumination in digital optics.

Separable binary-phase array illuminators for fan-out up to 1024 x 1024 and ~65% two-dimensional efficiency are designed by simulated annealing with constraints for maximizing the minimum feature size. A new nonseparable trapezoidal coding technique is introduced and applied to design high-efficiency (~75%-80%) array generators for fan-out up to 16 x 16. A rigorous electromagnetic diffraction theory is used to evaluate the range of validity of the scalar designs (both grating period and input angle are considered), to analyze fabrication errors (slanted groove walls and undercutting), and to design binary resonance-domain one-dimensional array generators with 90%-100% efficiency. Trapezoidal gratings for low fan-out (8 x 8), separable gratings for high fan-out (up to 128 x 128), and a 1 x 5 resonance domain (100% efficient) reflection grating are demonstrated experimentally.