Introduction: We sought to characterize the management of uncomplicated subcutaneous abscesses (SA) by Canadian emergency physicians (EPs). Methods: Cross-sectional study of CAEP membership. Subjects were emailed an invitation to an online survey, and two biweekly reminders. Wilcoxon rank sum test was used for association with age, and Chi Square and Fischers exact test were used for binary variables. Results: Response rate was 21.2 % (392 Reponses / 1850 surveyed). Duration of practice ranged from 30.2 % practising <= 5 years, to 25.7% practising >= 20 years. Teaching setting was described in 89.1% of responses. Irrigation with saline is performed by 57.1 % of EPs, tap water 2.1 %, or disinfectant 2.1% of EPs, with 39.1% not doing any irrigation. Approximately half (49.2%) typically do not pack or close wounds, while 40.6 % employ ribbon or gauze packing, and 1.6 % primary closure. Antibiotics are generally not prescribed by 16.8%. EPs prescribe antibiotics when suspecting surrounding cellulitis (84.2%), immunocompromised host (51.6%), MRSA (28.9%), or recurrence within 30 days (27.5 %). Cultures are taken almost always by 28.2%, half the time or less by 33.9%, never by 11.6%, and if MRSA is suspected by 33.9%. Follow-up instructions are with FP (56.7%), ED at 24 hours (5.91 %) or 48 hours (17.74 %), or not required (24.7%). Most EPs (90.9%) report having no standardized protocol for abscess management in their ED. EPs with fewer years in practice are more likely to make cruciate incisions (p=0.009), to generally not irrigate incisions (p=0.02), to culture if MRSA is suspected (p=0.02), and to prescribe antibiotics when suspecting MRSA (p=0.02) immune-compromised host (p=0.03), and in case of spontaneous treatment failure or recurrence (p=0.0004). EPs with more years in practice are more likely to pack with ribbon gauze (p=0.06), and to almost always swab for C&S (p=0.04) Conclusion: Practice variability and deviations from practice guidelines (i.e. IDSA, Choosing Wisely Canada) are noted. A knowledge translation exercise based on the guidelines for Canadian EPs would be useful.

Staircases of gravelly river terrace deposits in southern England occupy valleys typically underlain by frost-susceptible and brecciated bedrocks. The valleys developed during the Quaternary by alternating episodes of (1) brecciation, incision and planation through the bedrock, forming wide low-relief erosion surfaces; and (2) aggradation in braidplains of gravel a few meters thick that bury the erosion surfaces. A conceptual model to account for some of the terraces proposes that brecciation resulted from ice segregation in the ice-rich layer in the upper meters of Pleistocene permafrost, making them vulnerable to fluvial thermal erosion and therefore predisposing the bedrock to planation. The low gradients of the valleys were adjusted such that rivers transferred fine materials out of the basins but lacked the competence to remove gravel, which therefore accumulated within floodplains. The model challenges the prevailing view of incision during climate transitions. It attributes incision and planation to very cold and arid permafrost conditions, when rivers had limited discharges and hillslopes supplied limited volumes of stony debris into valley bottoms.

The valley floor of a 33.9 km2 watershed in western Colorado experienced gradual sedimentation from before ∼ 6765 to ∼ 500 cal yr BP followed by deep incision, renewed aggradation, and secondary incision. In contrast, at least four terraces and widespread cut-and-fill architecture in the valley floor downstream indicate multiple episodes of incision and deposition occurred during the same time interval. The upper valley fill history is atypical compared to other drainages in the Colorado Plateau.

One possible reason for these differences is that a bedrock canyon between the upper and lower valley prevented headward erosion from reaching the upper valley fill. Another possibility is that widespread, sand-rich, clay-poor lithologies in the upper drainage limited surface runoff and generally favored alluviation, whereas more clay-rich lithologies in the lower drainage resulted in increased surface runoff and more frequent incision. Twenty-two dates from valley fill charcoal indicate an approximate forest fire recurrence interval of several hundred years, similar to that from other studies in juniper–piñon woodlands. Results show that closely spaced vertical sampling of alluvium in headwater valleys where linkages between hillslope processes and fluvial activity are relatively direct can provide insight about the role of fires in alluvial chronologies of semi-arid watersheds.