OnlineStats.jl: A Julia package for statistics on data streams.

The growing prevalence of big and streaming data requires a new generation of tools. Data often has infinite size in the sense that new observations are continually arriving daily, hourly, etc. In recent years, several new technologies such as Kafka (Apache Software Foundation, n.d.-a) and Spark Streaming (Apache Software Foundation, n.d.-b) have been introduced for processing streaming data. Statistical tools for data streams, however, are under-developed and offer only basic functionality. The majority of statistical software can only operate on finite batches and require re-loading possibly large datasets for seemingly simple tasks such as incorporating a few more observations into an analysis. OnlineStats is a Julia (Bezanson, Edelman, Karpinski, & Shah, 2017) package for high-performance online algorithms. The OnlineStats framework is easily extensible, includes a large catalog of algorithms, provides primitives for parallel computing, and offers a weighting mechanism that allows new observations have a higher relative influence over the value of the statistic/model/visualization.

Anterior cingulate volume in pediatric bipolar disorder and autism.

BACKGROUND: An increasing number of studies indicate the anterior cingulate gyrus (ACG) may play a role in the attention deficits associated with pediatric bipolar disorder (BD). Age, medications, and intelligence quotient (IQ) may affect ACG volume; few studies have controlled for these effects. METHODS: We recruited 16 children with BD and 24 children with autism spectrum disorder (ASD); 15 children with no psychiatric diagnosis (NP) were also included. All participants were evaluated with the K-SADS and a DSM-IV Autism/Asperger's Checklist; the ADI-R was also administered to ASD participants shortly after the study began. The participants completed a brain MRI scan on a 1.5Tesla Signa GE scanner. We segmented the ACG and compared left and right ACG volumes between groups. The influence of medications on the ACG volume was assessed while controlling for the effects of age and IQ. RESULTS: The left ACG volume was significantly smaller in the BD group compared to the NP (p=0.004) and ASD (p=0.006) groups. No significant differences were found in the right ACG volume. These differences do not appear to be attributable to medication use or IQ. CONCLUSIONS: Pediatric BD patients have a smaller left ACG volume compared to NP children and children diagnosed with ASD. This replication and extension of previous studies suggest that the ACG volume abnormality may be a biomarker for BD.

Early acceleration of head circumference in children with fragile x syndrome and autism.

OBJECTIVE: Head circumference (HC) growth has been shown in several studies to be accelerated early in life in both fragile X syndrome (FXS) and autism spectrum disorders (ASDs), but the rates of growth have not been compared between those with only FXS and those with FXS and ASD (FXS + ASD). METHODS: We hypothesized that individuals with FXS + ASD would have significantly larger HCs from individuals with only FXS and that there would be an early acceleration of HC in both the FXS-only and FXS + ASD groups. HC measurements were available retrospectively for 44 males, five and younger, with FXS, of whom 22 also had ASD. Measurements over time were available for 24 of the 44 children. HC percentiles were compared between the groups in two ways: by focusing on cross-sectional subsamples and by fitting hierarchical linear models to the full sample. RESULTS: Neither group differed significantly from the norm in the first year of life (p > 0.2). At 30 months, the FXS + ASD group was 27 percentile points above the norm (p = .0125), whereas the FXS-only group did not differ from the norm. At 60 months, the FXS-only group was 21 percentile points above the norm (p = .029), whereas the FXS + ASD group did not differ from the norm. CONCLUSION: The group difference in HC growth rate may differentiate brain development in individuals with FXS-only versus those with FXS + ASD.