Turbulence in Boundary Flow of Superfluid 4^4He Triggered by Free Vortex Rings

The transition to turbulence in the boundary flow of superfluid $^4$He is investigated using a vortex--free vibrating wire. At high wire vibration velocities, we found that stable alternating flow around the wire enters a turbulent phase triggered by free vortex rings. Numerical simulations of vortex dynamics demonstrate that vortex rings can attach to the surface of an oscillating obstacle and expand unstably due to the boundary flow of the superfluid, forming turbulence. Experimental investigations indicate that the turbulent phase continues even after stopping the injection of vortex rings, which is also confirmed by the simulations.Comment: 4 pages, 4 figures, submitted to AP

Effects of principal stress rotation on the wave–seabed interactions

This paper simulates the wave–seabed interactions considering the principal stress rotation (PSR) by using the finite element method. The soil model is developed within the framework of kinematic hardening and the bounding surface concept, and it can properly consider the impact of PSR by treating the PSR generating stress rate independently. The simulation results are compared with centrifuge test results. The comparison indicates that the simulation with the soil model considering the PSR can better reproduce the test results on the development of pore water pressure and liquefaction than the soil model without considering the PSR. It indicates that it is important to consider the PSR impact in simulation of wave–seabed soil interactions

African stakeholders' views of research options to improve nutritional status in sub-Saharan Africa

Background Setting research priorities for improving nutrition in Africa is currently ad hoc and there is a need to shift the status quo in the light of slow progress in reducing malnutrition. This study explored African stakeholders' views on research priorities in the context of environmental and socio-demographic changes that will impact on nutritional status in Africa in the coming years. Methods Using Multi-Criteria Mapping, quantitative and qualitative data were gathered from 91 stakeholders representing 6 stakeholder groups (health professionals, food Industry, government, civil society, academics and research funders) in Benin, Mozambique, South Africa, Tanzania, Togo and Uganda. Stakeholders appraised six research options (ecological nutrition, nutritional epidemiology, community nutrition interventions, behavioural nutrition, clinical nutrition and molecular nutrition) for how well they could address malnutrition in Africa. Results Impact (28.3%), research efficacy (23.6%) and social acceptability (22.4%) were the criteria chosen the most to evaluate the performance of research options. Research on the effectiveness of community interventions was seen as a priority by stakeholders because they were perceived as likely to have an impact relatively quickly, were inexpensive and cost-effective, involved communities and provided direct evidence of what works. Behavioural nutrition research was also highly appraised. Many stakeholders, particularly academics and government were optimistic about the value of ecological nutrition research (the impact of environmental change on nutritional status). Research funders did not share this enthusiasm. Molecular nutrition was least preferred, considered expensive, slow to have an impact and requiring infrastructure. South Africa ranked clinical and molecular nutrition the highest of all countries. Conclusion Research funders should redirect research funds in Africa towards the priorities identified by giving precedence to develop the evidence for effective community nutrition interventions. Expanding research funding in behavioural and ecological nutrition was also valued and require multi-disciplinary collaborations between nutritionists, social scientists, agricultural and climate change scientists

A Conceptual Framework for Healthy Eating Behavior in Ecuadorian Adolescents: A Qualitative Study

Objective: The objective of this study was to identify factors influencing eating behavior of Ecuadorian adolescents - from the perspective of parents, school staff and adolescents - to develop a conceptual framework for adolescents’ eating behavior. Study design: Twenty focus groups (N = 144 participants) were conducted separately with adolescents aged 11–15 y (n (focus groups) = 12, N (participants) = 80), parents (n = 4, N = 32) and school staff (n = 4, N = 32) in rural and urban Ecuador. A semi-structured questioning route was developed based on the ‘Attitude, Social influences and Self-efficacy’ model and the socio-ecological model to assess the relevance of behavioral and environmental factors in low- and middle-income countries. Two researchers independently analyzed verbatim transcripts for emerging themes, using deductive thematic content analysis. Data were analyzed using NVivo 8. Results: All groups recognized the importance of eating healthily and key individual factors in Ecuadorian adolescents’ food choices were: financial autonomy, food safety perceptions, lack of self-control, habit strength, taste preferences and perceived peer norms. Environmental factors included the poor nutritional quality of food and its easy access at school. In their home and family environment, time and convenience completed the picture as barriers to eating healthily. Participants acknowledged the impact of the changing socio-cultural environment on adolescents’ eating patterns. Availability of healthy food at home and financial constraints differed between settings and socio-economic groups. Conclusion: Our findings endorse the importance of investigating behavioral and environmental factors that influence and mediate healthy dietary behavior prior to intervention development. Several culture-specific factors emerged that were incorporated into a conceptual framework for developing health promotion interventions in Ecuador

Low Lipoprotein(a) Concentration Is Associated with Cancer and All-Cause Deaths: A Population-Based Cohort Study (The JMS Cohort Study)

Background: Experimental studies support the anti-neoplastic effect of apo(a), but several clinical studies have reported contradictory results. The purpose of this study was to determine whether a low lipoprotein(a) [Lp(a)] concentration is related to mortality from major causes of death, especially cancer. Methods The subjects were 10,413 participants (4,005 men and 6,408 women) from a multi-center population-based cohort study in Japan (The Jichi Medical School cohort study). The average age at registration was 55.0 years, and the median observation period was 4,559 days. As the estimated hazard ratio was high for both the low and very high Lp(a) levels, we defined two Lp(a) groups: a low Lp(a) group [Lp(a)<80 mg/L] and an intermediate-to-high Lp(a) group [Lp(a)≥80]. Participants who died from malignant neoplasms (n = 316), cardiovascular disease (202), or other causes (312) during the observation period were examined. Results: Cumulative incidence plots showed higher cumulative death rates for the low Lp(a) group than for the intermediate-to-high Lp(a) group for all-cause, cancer, and miscellaneous-cause deaths (p<0.001, p = 0.03, and p = 0.03, respectively). Cox proportional hazards analyses with the sex and age of the participants, body mass index, and smoking and drinking histories as covariates showed that a low Lp(a) level was a significant risk for all-cause, cancer, and miscellaneous-cause deaths (p<0.001, p = 0.003, and p = 0.01, respectively). The hazard ratio (95% CI) [1.48, 1.15–1.92] of a low Lp(a) level for cancer deaths was almost the same as that for a male sex (1.46, 1.00–2.13). Conclusions: This is the first report to describe the association between a low Lp(a) level and all-cause or cancer death, supporting the anti-neoplastic effect of Lp(a). Further epidemiological studies are needed to confirm the present results

The bii4africa dataset of faunal and floral population intactness estimates across Africa’s major land uses

Sub-Saharan Africa is under-represented in global biodiversity datasets, particularly regarding the impact of land use on species’ population abundances. Drawing on recent advances in expert elicitation to ensure data consistency, 200 experts were convened using a modified-Delphi process to estimate ‘intactness scores’: the remaining proportion of an ‘intact’ reference population of a species group in a particular land use, on a scale from 0 (no remaining individuals) to 1 (same abundance as the reference) and, in rare cases, to 2 (populations that thrive in human-modified landscapes). The resulting bii4africa dataset contains intactness scores representing terrestrial vertebrates (tetrapods: ±5,400 amphibians, reptiles, birds, mammals) and vascular plants (±45,000 forbs, graminoids, trees, shrubs) in sub-Saharan Africa across the region’s major land uses (urban, cropland, rangeland, plantation, protected, etc.) and intensities (e.g., large-scale vs smallholder cropland). This dataset was co-produced as part of the Biodiversity Intactness Index for Africa Project. Additional uses include assessing ecosystem condition; rectifying geographic/ taxonomic biases in global biodiversity indicators and maps; and informing the Red List of Ecosystems