Dancing in the Dark - the never-resting ballet of animal life under the Arctic sea ice

While the Arctic Ocean is changing rapidly, we have barely begun to understand the dynamics of animal life under the permanent sea ice, as it exists today. During the MOSAiC expedition, RV Polarstern was moored to an ice floe and drifted more than 3,000 km across the central Arctic Ocean, enabling multidisciplinary observations of the inter-linked processes in atmosphere, sea ice, ocean and ecosystem. We studied year-round changes in diversity, abundance, vertical distribution, physiology, and ontogeny of Arctic ectotherms from the pack ice at the surface into the deep ocean. Imaging profilers show the fine-scale distribution of zooplankton at high resolution, how the vertical distribution and aggregation of different species change with season, and how zooplankton species prepare for reproduction already in the deepest winter. Systematic sampling with nets shows that the pelagic food web was active from the under-ice habitat down to bathypelagic depths throughout the winter, supporting a variety of predators, such as amphipods, polar cod (Boreogadus saida), and the understudied diversity of jellyfish. The first-ever hydroacoustic survey of the Transpolar Drift recorded the change in pelagic biomass in time and space, and highlights brief periods of diel vertical migration in spring and autumn. Video surveys with a Remotely Operated Vehicle (ROV) documented the use of the under-ice habitat by polar cod and various jellyfishes. A new under-ice net mounted on the ROV can provide new insights in the connection of the life cycles of sympagic amphipods with the seasonal change of sea-ice- and water column properties. We collected thousands of samples for the analysis of condition, physiological parameters, food preference, microplastic, and trophic biomarkers, and conducted numerous rate process measurements including respiration, feeding and reproduction, for key species with the goal of unravelling the sources and fate of carbon in the food web. The first results demonstrate how sampling techniques from the days of Nansen in combination with modern technology can unfold a comprehensive picture of the contribution of Arctic fauna to ecosystem functioning and biogeochemical cycles, as well as their resilience and potential changes in a future seasonally ice-covered Arctic Ocean. We will present and discuss first results and conclusions emerging from our data with regard to the scientific objectives of MOSAiC

Dental Health and Mortality in People With End-Stage Kidney Disease Treated With Hemodialysis: A Multinational Cohort Study

Background Dental disease is more extensive in adults with chronic kidney disease, but whether dental health and behaviors are associated with survival in the setting of hemodialysis is unknown. Study Design Prospective multinational cohort. Setting & Participants 4,205 adults treated with long-term hemodialysis, 2010 to 2012 (Oral Diseases in Hemodialysis [ORAL-D] Study). Predictors Dental health as assessed by a standardized dental examination using World Health Organization guidelines and personal oral care, including edentulousness; decayed, missing, and filled teeth index; teeth brushing and flossing; and dental health consultation. Outcomes All-cause and cardiovascular mortality at 12 months after dental assessment. Measurements Multivariable-adjusted Cox proportional hazards regression models fitted with shared frailty to account for clustering of mortality risk within countries. Results During a mean follow-up of 22.1 months, 942 deaths occurred, including 477 cardiovascular deaths. Edentulousness (adjusted HR, 1.29; 95% CI, 1.10-1.51) and decayed, missing, or filled teeth score ≥ 14 (adjusted HR, 1.70; 95% CI, 1.33-2.17) were associated with early all-cause mortality, while dental flossing, using mouthwash, brushing teeth daily, spending at least 2 minutes on oral hygiene daily, changing a toothbrush at least every 3 months, and visiting a dentist within the past 6 months (adjusted HRs of 0.52 [95% CI, 0.32-0.85], 0.79 [95% CI, 0.64-0.97], 0.76 [95% CI, 0.58-0.99], 0.84 [95% CI, 0.71-0.99], 0.79 [95% CI, 0.65-0.95], and 0.79 [95% CI, 0.65-0.96], respectively) were associated with better survival. Results for cardiovascular mortality were similar. Limitations Convenience sample of clinics. Conclusions In adults treated with hemodialysis, poorer dental health was associated with early death, whereas preventive dental health practices were associated with longer survival

Seasonal changing use of the surface layer by Arctic zooplankton

Less and thinner sea ice characterizes the new Arctic, but our knowledge on zooplankton dynamics in relation to sea ice conditions in the Central Arctic Ocean is scarce, especially during the Polar night. To investigate the seasonal dynamics of the interaction of zooplankton and sea ice, we sampled zooplankton with a net (150 µm mesh, opening 0.24 m2) attached to a Remotely Operating Vehicle (ROV-net). In approximately weekly intervals, we conducted horizontal tows at the ice-water interface and at 10 m under the ice and occasionally also in > 20m. Once each in summer and in winter, we sampled over 24-hours to investigate the diel variability of zooplankton distribution. All net samples were preserved in 4% formalin onboard. At AWI, they were size-fractionated, split into aliquots and scanned with the ZooScan, yielding >200k of images presenting single objects. These images were uploaded to the web-based application EcoTaxa and classified according to taxonomical criteria. Here, we will present the zooplankton species composition and abundances under the MOSAiC ice-floe, and we will discuss the importance of sea-ice for zooplankton population dynamics

Patient satisfaction with in-centre haemodialysis care: An International Survey

Objectives: To evaluate patient experiences of specific aspects of haemodialysis care across several countries.Design: Cross-sectional survey using the Choices for Healthy Outcomes in Caring for End-Stage Renal Disease (CHOICE) questionnaire.Setting: Haemodialysis clinics within a single provider in Europe and South America.Participants: 2748 adults treated in haemodialysis. Primary and secondary outcomes: The primary outcome was patient satisfaction with overall care. Secondary outcomes included patient experiences of individual aspects of dialysis care.Results: 2145 (78.1%) adults responded to the questionnaire. Fewer than half (46.5% (95% CI 44.5% to 48.6%)) rated their overall care as excellent. Global perceptions of care were uninfluenced by most respondent characteristics except age and depressive symptoms; older respondents were less critical of their care (adjusted OR for excellent rating 1.44 (1.01 to 2.04)) and those with depressive symptoms were less satisfied (0.56 (0.44 to 0.71)). Aspects of care that respondents most frequently ranked as excellent were staff attention to dialysis vascular access (54% (52% to 56%)); caring of nurses (53% (51% to 55%)); staff responsiveness to pain or discomfort (51% (49% to 53%)); caring, helpfulness and sensitivity of dialysis staff (50% (48% to 52%)); and ease of reaching dialysis staff by telephone (48% (46% to 50%)). The aspects of care least frequently ranked as excellent were information provided when choosing a dialysis modality (23% (21% to 25%)), ease of seeing a social worker (28% (24% to 32%)), information provided about dialysis (34% (32% to 36%)), accuracy of information from nephrologist (eg, about prognosis or likelihood of a kidney transplant; 37% (35% to 39%)) and accuracy of nephrologists' instructions (39% (36% to 41%)).Conclusions: Haemodialysis patients are least satisfied with the complex aspects of care. Patients' expectations for accurate information, prognosis, the likelihood of kidney transplantation and their options when choosing dialysis treatment need to be considered when planning healthcare research and practices