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Objective: To investigate gastrointestinal (GI)‐related physician visits and drug dispensations in the 5 years preceding a first recorded demyelinating event or multiple sclerosis (MS) onset. Methods: Using linked administrative and clinical data from British Columbia (1996–2013), Canada, we identified an administrative cohort via a validated algorithm (n = 6863), a clinical cohort diagnosed at a MS clinic (n = 966), and matched controls (administrative cohort: n = 31,865; clinical cohort: n = 4534). In each cohort, the 5 years before a first demyelinating event or MS symptom onset (i.e., index date) were examined. We compared rates of GI‐related physician visits and risk of ≥1 GI‐related dispensation between MS cases and controls using negative binomial and robust Poisson models. Sex differences were tested using interaction terms. Results: The administrative cohort MS cases had higher rates of physician visits related to gastritis and duodenitis (adjusted rate/risk ratio (aRR):1.42, 95% CI: 1.10–1.83) and diseases of the esophagus (aRR: 1.46, 95% CI: 1.06–2.02) prior to the index date. MS cases also had greater risk of at least one dispensation for several drug classes, including constipation‐related (aRR: 1.82, 95% CI: 1.50–2.22), antiemetics/antinauseants (aRR: 1.64, 95% CI: 1.43–1.89), and propulsives (promotility drugs; aRR: 1.62, 95% CI: 1.47–1.79). Men had a disproportionally higher relative risk for propulsives than women (aRR: men = 2.32, 95% CI: 1.79–3.00; women = 1.54, 95% CI: 1.36–1.72). Several findings were similar in the smaller clinical cohort though none reached statistical significance. Interpretation: GI‐related physician visits and drug dispensations were more common in the 5 years before the first demyelinating event versus matched controls. GI symptoms are a measurable feature of the prodromal or early phase of MS, with a sex difference evident. [ABSTRACT FROM AUTHOR]

Tropospheric and lower‐stratospheric motions at mesoscales and larger are a mixture of waves and two‐dimensional (2‐D) turbulence. Determining their relative importance is necessary, since waves are capable of coordinated systematic momentum transport accompanying the wave propagation, and associated wind forcing, in ways that 2‐D turbulence is not. This can impact weather forecasting. Using a network of ten windprofiler radars in eastern Ontario and western Quebec in Canada, plus an additional one in the Arctic, the relative roles of internal gravity (buoyancy) waves and two‐dimensional turbulence are examined at temporal scales from about 3–4 hrs to several tens of hours (horizontal spatial scales of typically one or two hundred kilometres to a few thousand kilometres), with the purpose of investigating the respective roles of these two distinct characteristic fluid motions as functions of location, season and year. The emphasis is on studies of spectral slope variability, rather than absolute spectral magnitudes, giving a perspective not previously substantially presented. In particular, we have found a frequency band in which gravity‐wave Doppler shifting produces distinctly different spectral slopes than those predicted for 2‐D turbulence, and these differences are employed to distinguish the flow fields. The network used (excluding the Arctic site) covers an area of ∼106 km2 and includes a variety of different terrains. Radial velocities have been recorded on time scales of minutes for data lengths covering durations of up to 12 years. Altitude coverage is from 1 km to typically 14 km, at 500 m resolution. Results suggest a region from ∼2 to ∼5 km altitude (deeper for some radars) where waves are weaker and 2‐D turbulence appears to be generally more significant, but where occasional bursts of gravity‐wave activity can occur, while above typically 6–8 km, gravity waves increase in significance. There are distinct site‐to‐site variations. [ABSTRACT FROM AUTHOR]