Digital elevation models of the sea-ice surface from airborne laser scanning during MOSAiC.

Airborne laser scanners (ALS) are used to map the sea-ice surface at sub-meter resolution. We conducted 64 flights over the Arctic sea ice between September 2019 and September 2020 during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition to measure sea-ice surface elevation. The flights ranged from repeated, local-scale 5 × 5 km floe grid surveys to regional-scale transects more than 100 km long.

Sea ice surface temperatures from helicopter-borne thermal infrared imaging during the MOSAiC expedition.

The sea ice surface temperature is important to understand the Arctic winter heat budget. We conducted 35 helicopter flights with an infrared camera in winter 2019/2020 during the Multidisciplinary Drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. The flights were performed from a local, 5 to 10 km scale up to a regional, 20 to 40 km scale.

Arctic warming interrupts the Transpolar Drift and affects long-range transport of sea ice and ice-rafted matter.

Sea ice is an important transport vehicle for gaseous, dissolved and particulate matter in the Arctic Ocean. Due to the recently observed acceleration in sea ice drift, it has been assumed that more matter is advected by the Transpolar Drift from shallow shelf waters to the central Arctic Ocean and beyond. However, this study provides first evidence that intensified melt in the marginal zones of the Arctic Ocean interrupts the transarctic conveyor belt and has led to a reduction of the survival rates of sea ice exported from the shallow Siberian shelves (-15% per decade).

Export of algal biomass from the melting Arctic sea ice.

In the Arctic, under-ice primary production is limited to summer months and is restricted not only by ice thickness and snow cover but also by the stratification of the water column, which constrains nutrient supply for algal growth. Research Vessel Polarstern visited the ice-covered eastern-central basins between 82° to 89°N and 30° to 130°E in summer 2012, when Arctic sea ice declined to a record minimum. During this cruise, we observed a widespread deposition of ice algal biomass of on average 9 grams of carbon per square meter to the deep-sea floor of the central Arctic basins.

Dronabinol and retinal hemodynamics in humans.

Purpose: To investigate the effects of oral cannabinoids on retinal hemodynamics assessed by video fluorescein angiography in healthy subjects.

Design: Interventional study.

Methods: In a self-experiment, the cannabinoid dronabinol (delta-9-tetrahydrocannabinol [THC]) was administered orally to eight healthy medical doctors (7.

Short-wavelength automated perimetry in patients with diabetes mellitus without macular edema.

Background: The short-wavelength-sensitive (SWS) cone-mediated sensitivity is a sensitive indicator of functional changes of the macula in diabetic maculopathy. This study was performed to investigate whether functional losses of the macula are detectable in patients without a significant macular edema.

Methods: In 45 patients with diabetes mellitus with clear optical media and no macular edema, conventional white-on-white perimetry (WWP) and short-wavelength automated perimetry (SWAP) were performed in the central 10-deg field.