23 research outputs found
Mesoscale observations of Joule heating near an auroral arc and ion-neutral collision frequency in the polar cap E region
We report on the first mesoscale combined ionospheric and thermospheric observations, partly in the vicinity of an auroral arc, from Svalbard in the polar cap on 2 February 2010. The EISCAT Svalbard radar employed a novel scanning mode in order to obtain F and E region ion flows over an annular region centered on the radar. Simultaneously, a colocated Scanning Doppler Imager observed the E region neutral winds and temperatures around 110 km altitude using the 557.7 nm auroral optical emission. Combining the ion and neutral data permits the E region Joule heating to be estimated with an azimuthal spatial resolution of âź64 km at a radius of âź163 km from the radar. The spatial distribution of Joule heating shows significant mesoscale variation. The ion-neutral collision frequency is measured in the E region by combining all the data over the entire field of view with only weak aurora present. The estimated ion-neutral collision frequency at âź113 km altitude is in good agreement with the MSIS atmospheric model
A review of spatial causal inference methods for environmental and epidemiological applications
The scientific rigor and computational methods of causal inference have had
great impacts on many disciplines, but have only recently begun to take hold in
spatial applications. Spatial casual inference poses analytic challenges due to
complex correlation structures and interference between the treatment at one
location and the outcomes at others. In this paper, we review the current
literature on spatial causal inference and identify areas of future work. We
first discuss methods that exploit spatial structure to account for unmeasured
confounding variables. We then discuss causal analysis in the presence of
spatial interference including several common assumptions used to reduce the
complexity of the interference patterns under consideration. These methods are
extended to the spatiotemporal case where we compare and contrast the potential
outcomes framework with Granger causality, and to geostatistical analyses
involving spatial random fields of treatments and responses. The methods are
introduced in the context of observational environmental and epidemiological
studies, and are compared using both a simulation study and analysis of the
effect of ambient air pollution on COVID-19 mortality rate. Code to implement
many of the methods using the popular Bayesian software OpenBUGS is provided
Atypical Neural Functions Underlying Phonological Processing and Silent Rehearsal in Children Who Stutter
Phonological processing was examined in school-age children who stutter (CWS) by assessing their performance and recording event related brain potentials (ERPs) in a visual rhyming task. CWS had lower accuracy on rhyming judgments, but the cognitive processes that mediate the comparisons of the phonological representations of words, as indexed by the rhyming effect (RE) ERP, were similar for the stuttering and normally fluent groups. Thus the lower behavioral accuracy of rhyming judgments by the CWS could not be attributed to that particular stage of processing. Instead, the neural functions for processes preceding the RE, indexed by the N400 and CNV elicited by the primes and the N400 elicited by the targets, suggest atypical processing that may have resulted in less efficient, less accurate rhyming judgment for the CWS. Based on the present results, it seems likely that the neural processes related to phonological rehearsal and target word anticipation, as indexed by the CNV, are distinctive for CWS at this age. Further, it is likely that the relative contributions of the left and right hemispheres differ in CWS in the stage of processing when linguistic integration occurs, as indexed by the N400. Taken together, these results suggest that CWS may be less able to form and retain a stable neural representation of the prime onset and rime as they anticipate the target presentation, which may lead to lower rhyming judgment accuracy
Spelling Processes of Children with Nonsyndromic Cleft Lip and/or Palate: A Preliminary Study
Objective: To compare the cognitive-linguistic processes underlying spelling performance of children with cleft lip and/or palate with those of typically developing children. Design: An assessment battery including tests of hearing, articulation, verbal short-term and working memory, and phonological awareness, as well as word and nonword spelling, was administered to both groups. Participants: A total of 15 children with nonsyndromic cleft lip and/or palate were casematched by age and sex to 15 typically developing children. The children were aged between 6 and 8 years and were bilingual, with English the dominant language. Results: Wilcoxon signed-rank tests revealed that the performance of children with cleft lip and/or palate was significantly poorer on phoneme deletion and nonword spelling (P < .05) compared with typically developing children. Spearman correlation analyses revealed different relationships between the cognitive-linguistic and spelling measures for the cleft lip and/or palate and typically developing groups. Conclusions: Children with cleft lip and/or palate underachieve in phonological awareness and spelling skills. To facilitate early intervention for literacy problems, speech-language pathologists should routinely assess the cognitive-linguistic processing of children with cleft lip and/or palate, especially phonological awareness, as part of their case management protocols