Hyperhomocysteinemia, as an Independent Risk Factor for Retinal Venous Occlusion in an Indian Population

Total plasma homocysteine was analysed in 64 cases of retinal vein occlusion (RVO) of which 24 cases of central retinal vein occlusion (CRVO) and 40 cases of branch retinal vein occlusion (BRVO) and compared with 45 age and sex matched control. Homocysteine was significantly increased in RVO cases in respect to control (P < 0.001). Analysis also revealed that prevalence of rise of plasma homocysteine was more in cases of CRVO (OR = 13) than that of BRVO (OR = 5.03).     

Visual-temporal processing in reading-disabled and normal twins

Percent contrast thresholds for the detection of 1 or 8 cycle/degree sinusoidalgratings flickering in counter-phase at 1 or 10Hz were evaluated in 356 8–19 year old twinsand their school-age siblings. 107 of the twinshad a school history of reading disability.Subjects adjusted contrast levels to thresholdfrom above and below in a total of 32 trialsover about 12 minutes. Internal reliability foreach of the 4 stimulus conditions was 0.8, andeach stimulus condition was similarlycorrelated at 0.2–0.3 with several measuresof reading and phonological processing,suggesting modest relations with readingdeficits for both parvocellular (sustained) andmagnocellular (transient) visual processes. Thevariance in the word-reading measure that wasrelated to visual contrast thresholds waslargely shared with full-scale IQ, although IQand reading each also accounted for small(1%) but statistically significant amounts ofadditional independent variance in contrastthresholds. Word reading and nonword readingalso accounted for largely overlapping variancein contrast thresholds, but with a small (1%)amount of independent variance for nonwordreading. A behavioral-genetic analysis of themonozygotic and dizygotic twin correlationsindicated no significant genetic influence onindividual differences in contrast-thresholdlevels.     

A Global Investigation of Granger Causality between Information Infrastructure Investment and Service-Sector Growth

Over the past two decades, both developed and developing countries have been investing a significant portion of their resources in the creation of an information infrastructure. However, speculation abounds regarding the efficacy of information infrastructure investments, especially when the opportunity cost for investing in information technology (IT) is measurably high among developing nations. This longitudinal study introduces and explores infrastructure development and service-sector growth as key metrics for IT investment success. It also traces the notional evidence of IT infrastructure development as mediating the causal relationship between information infrastructure investments and service-sector growth. Using data from low-income, middle-income, and high-income countries, the mediating and lagged impact of information infrastructure on service-sector growth reveals that information infrastructure development does play a significant role as a mediator. It points out that information infrastructure investments can be a misleading causal antecedent if countries fail to develop their infrastructure. It also provides evidence of a recursive relationship between infrastructure development and service-sector growth. An exploratory time-series analysis across different country categories suggests that information infrastructures must be properly developed to reconcile the paradox. In addition, exploratory tests reveal a distinct divergence between infrastructure investments and infrastructure development among different country tiers.