ABSTRACT
Human activity causes vibrations that propagate into the ground as high-frequency seismic waves. Measures to mitigate the coronavirus disease 2019 (COVID-19) pandemic caused widespread changes in human activity, leading to a months-long reduction in seismic noise of up to 50%. The 2020 seismic noise quiet period is the longest and most prominent global anthropogenic seismic noise reduction on record. Although the reduction is strongest at surface seismometers in populated areas, this seismic quiescence extends for many kilometers radially and hundreds of meters in depth. This quiet period provides an opportunity to detect subtle signals from subsurface seismic sources that would have been concealed in noisier times and to benchmark sources of anthropogenic noise. A strong correlation between seismic noise and independent measurements of human mobility suggests that seismology provides an absolute, real-time estimate of human activities.
Subject(s)
Activities of Daily Living , Coronavirus Infections/epidemiology , Noise , Pneumonia, Viral/epidemiology , COVID-19 , Humans , Pandemics , QuarantineABSTRACT
BACKGROUND: Children with sickle cell disease (SCD) demonstrate deficits in cognitive and academic functioning. This study compared the visual motor integration (VMI) skills of children with SCD to non-SCD sibling controls. PROCEDURE: In total, 105 participants (67 patients with SCD, 38 controls) were recruited during a routine clinic visit. Each participant was administered the Grooved Pegboard Test, a test of manual dexterity and the Beery-Buktenica Developmental Test of VMI, a measure of graphomotor skills. RESULTS: Children with SCD demonstrated average (M=89.61, SE=3.08) fine manual dexterity and speed, but more complex fine motor functioning (graphomotor skills) (M=77.61, SE=1.65) was impaired. Relative to healthy siblings, children with SCD were not found to have different fine manual dexterity and speed (P=0.617). Patients with SCD were found to have significantly worse graphomotor skills (P=0.04). CONCLUSIONS: Children with SCD were found to have average basic fine motor dexterity and speed, but impaired VMI, a more complex fine motor skill. This finding is significant given the functional importance of complex fine motor skills in early academic activities.
Subject(s)
Anemia, Sickle Cell/psychology , Motor Skills Disorders , Psychomotor Performance , Adolescent , Case-Control Studies , Child , Child, Preschool , Cognition Disorders , Female , Humans , Learning Disabilities , Male , SiblingsABSTRACT
Analyses of Ps and Sp receiver functions from datasets collected by permanent and temporary seismic stations, image a seismic discontinuity, due to a negative velocity contrast across the entire Eastern Alps. The receiver functions show the presence of the discontinuity within the upper mantle with a resolution of tens of kilometers laterally. It is deeper (100-130 km) below the central portion of the Eastern Alps, and shallower (70-80 km) towards the Pannonian Basin and in the Central Alps. Comparison with previous studies renders it likely that the observed discontinuity coincides with the lithosphere-asthenosphere boundary (LAB) east of 15°E longitude, while it could be associated with a low velocity zone west of 15°E.
