The extent of near-surface permafrost, or perennially frozen ground within 3 m of the surface, was estimated for the Mackenzie River delta by determining its association with riparian vegetation communities in the field, and by subsequently mapping these vegetation communities using SPOT-5 data and the supervised maximum-likelihood classification technique. Near-surface permafrost was absent beneath willow-horsetail (Salix-Equisetum) vegetation communities on point bars and alluvial islands throughout the delta and beneath horsetail (Equisetum) communities in the southern and central delta. Near-surface permafrost was found beneath all other vegetation communities and land surface types. Multispectral SPOT-5 data were classified with overall accuracies greater than 80 per cent. Using the remotely sensed vegetation community data, near-surface permafrost was estimated to occur beneath 93 per cent, 95 per cent and 96 per cent of the land surface within the investigation areas of the southern, central and northern delta, respectively. In contrast to the most recent Permafrost Map of Canada, these results indicate that the Mackenzie Delta is part of the continuous permafrost zone. Figure 3 Vegetation communities in the delta: (a) horsetail; (b) willow-horsetail; (c) alder; (d) spruce; (e) sedge; and (f) Salix richardsonii. Spruce forests are absent in the northern delta.

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Background: Building capacity in hepatitis B virus prevention and management for medical students and health professionals is one of the pillars of the national viral hepatitis control strategy. Methods: A cross-sectional study was conducted at eight medical universities from the northern, central and southern regions of the country between May and November 2020 using a systematic random sampling technique. Results: Among 2000 participants, 84.2% reported they had been tested for hepatitis B and 83.9% had received the hepatitis B vaccine. The mean knowledge, attitude, practice score was 40.2 out of 54 (74.4%) with only 19.9% of the study participants obtaining a good score. In multivariate analysis, fifth year students, students from central universities, students who had tested positive for hepatitis B and students who had received hepatitis B vaccine or had encountered patients with chronic hepatitis B had significantly higher knowledge score (p < 0.05). The study showed lack of trust in the hepatitis B vaccine safety and lack of confidence in providing counselling, testing and management of patients with chronic hepatitis B. Conclusion: Findings from our research emphasized an immediate need to improve the medical schools’ training curriculum in Vietnam to enable students’ readiness in hepatitis B prevention and management.

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