Jump Rope Vortex in Liquid Metal Convection

Understanding large scale circulations (LSCs) in turbulent convective systems is important for the study of stars, planets and in many industrial applications. The canonical model of the LSC is quasi-planar with additional horizontal sloshing and torsional modes [Brown E, Ahlers G (2009) J. Fluid Mech. 638:383--400; Funfschilling D, Ahlers G (2004) Phys. Rev. Lett. 92(19):194502; Xi HD et al. (2009) Phys. Rev. Lett. 102(4):044503; Zhou Q et al. (2009) J. Fluid Mech. 630:367--390]. Using liquid gallium as the working fluid, we show via coupled laboratory-numerical experiments that the LSC in a tank with aspect ratios greater than unity takes instead the form of a "jump rope vortex", a strongly three-dimensional mode that periodically orbits around the tank following a motion much like a jump rope on a playground. Further experiments show that this jump rope flow also exists in more viscous fluids such as water, albeit with a far smaller signal. Thus, this new jump rope mode is an essential component of the turbulent convection that underlies our observations of natural systems

Räumliche Charakterisierung der hydraulischen Leitfähigkeit inalluvialen Schotter-Grundwasserleitern: EinMethodenvergleich

Zusammenfassung: Für die Modellierung des Stofftransportes im Grundwasser im Maßstabsbereich von 10-100m sind detaillierte Kenntnisse der räumlichen Verteilung der hydraulischen Leitfähigkeit unabdingbar. Bei einem Testfeld (10×20m) im alluvialen Schotter-Grundwasserleiter des voralpinen Thurtals (Schweiz) wurden vier unterschiedliche Methoden, wirksam auf verschiedenen Messskalen, angewandt, um diesen Parameter zu bestimmen. Der Vergleich der Ergebnisse zeigte, dass tiefenaufgelöste Slugtests verlässliche Resultate für den gefragten Maßstab liefern. Für deren Auswertung ist ein plausibler Wert für das Anisotropieverhältnis der hydraulischen Leitfähigkeit (K v/K h) nötig, welches aus einem entsprechend ausgewerteten Pumpversuch erfasst werden konnte. Die integralen Resultate von Pumpversuchen entsprechen tendenziell der oberen Grenze des natürlichen Spektrums der hydraulischen Leitfähigkeit auf dem Maßstab des Testfeldes. Flowmetermessungen sind zu empfehlen, wenn primär die relative Verteilung der hydraulischen Leitfähigkeit interessiert, und Siebanalysen, wenn eine grobe Abschätzung der hydraulischen Leitfähigkeit ausreich

Intergenerational resource sharing and mortality in a global perspective

Resource sharing has always been a central component of human sociality. Children require heavy investments in human capital; during working years, help is needed due to illness, disability, or bad luck. While hunter-gatherer elders assisted their descendants, more recently, elderly withdraw from work and require assistance as well. Willingness to share has been critically important for our past evolutionary success and our present daily lives. Here, we document a strong linear relationship between the public and private sharing generosity of a society and the average length of life of its members. Our findings from 34 countries on six continents suggest that survival is higher in societies that provide more support and care for one another. We suggest that this support reduces mortality by meeting urgent material needs, but also that sharing generosity may reflect the strength of social connectedness, which itself benefits human health and wellbeing and indirectly raises survival

Intergenerational Family Support and the Health and Well-Being of Older Adults in Sub-Saharan Africa:A systematic review

Many countries in sub Saharan Africa (SSA) have experienced an ageing of their population and this is projected to increase in the future. Family support is the main source of support for most older adults in SSA. Yet, relatively little is known about intergenerational family support provided to older adults in SSA and its effects on their health and well-being. This review adds to the scientific discussion synthesizing the health and well-being effects of family support provided to older adults in SSA. A systematic literature review was conducted to identify and analyze studies that focus on the provision of family support to older adults and its effects on their health and well-being. Eight (8) databases and other sources were searched for English Language publications between January 2000 and May 2020. Narrative synthesis was used to summarize the findings of the studies included. Out of 2426 records screened and 26 full-text publications retrieved and assessed, 8 studies were included in the review. The results suggest that receiving social and financial support from family as well as having frequent contact with family were positively related to better psychological well-being, self-rated health, and quality of life of older adults in SSA

The progression of the tobacco epidemic in India on the national and regional level, 1998-2016

BACKGROUND: Evidence regarding the progression of the tobacco epidemic remains fragmented in low- and middle-income countries. In India, most of the studies that examined tobacco consumption focused on one time point, on the country as a whole, and on men. Despite important gender differences in tobacco consumption, vast economic and cultural differences exist within India. We, therefore, assessed the progression of the tobacco epidemic in India on both the national and the regional level, by gender. METHODS: We use information on current tobacco use among Indians aged 15–49 from three rounds of the National Family Health Survey (NFHS) (1998-99, 2005-06, 2015-16) to estimate the age-standardized sex specific smoking and smokeless tobacco prevalence across India and its states. RESULTS: Age-standardized tobacco use prevalence in India increased between 1998-1999 and 2005-2006, and declined from 2005-2006 to 2015–2016, simultaneously for men and women. There are substantial spatial differences in the progression of the tobacco epidemic in India. While tobacco use declined in the majority of states, we observe high and increasing use for men in the north-eastern states of Manipur, Mizoram and Nagaland, and for women in the western state of Gujarat and north-eastern state of Manipur. We observed even more states with a recent increasing prevalence in either tobacco smoking or smokeless tobacco. Throughout, prevalence of tobacco use has been higher among men than women for all Indian regions, and remained higher than the national average in the north-eastern states. CONCLUSIONS: Our results suggest that India and the majority of its states experienced a ‘compressed tobacco epidemic’ in which the prevalence of tobacco consumption increased and decreased simultaneously for women and men over a comparatively short period of time. Despite the overall progress India made in reducing tobacco use, further lowering tobacco consumption remains a public health priority, as the prevalence of smoking and/or smokeless tobacco use remains high in a number of states. We therefore conclude that tobacco regulations should be expanded with the aim of reducing the overall health burden associated with tobacco consumption across India. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12889-021-12261-y

Oscillatory thermal-inertial flows in liquid metal rotating convection

We present the first detailed thermal and velocity field characterization of convection in a rotating cylindrical tank of liquid gallium, which has thermophysical properties similar to those of planetary core fluids. Our laboratory experiments, and a closely associated direct numerical simulation, are all carried out in the regime prior to the onset of steady convective modes. This allows us to study the oscillatory convective modes, sidewall modes and broadband turbulent flow that develop in liquid metals before the advent of steady columnar modes. Our thermo-velocimetric measurements show that strongly inertial, thermal wind flows develop, with velocities reaching those of comparable non-rotating cases. Oscillatory bulk convection and wall modes coexist across a wide range of our experiments, along with strong zonal flows that peak in the Stewartson layer, but that extend deep into the fluid bulk in the higher supercriticality cases. The flows contain significant time-mean helicity that is anti-symmetric across the midplane, demonstrating that oscillatory liquid metal convection contains the kinematic components to sustain system-scale dynamo generation.Comment: 29 pages, 12 figure

Mortality convergence in the enlarged European Union:a systematic literature review

BACKGROUND: The high mortality rates in the European Union (EU) Member States that acceded in 2004 sparked political interest in mortality convergence. Whether mortality is converging in the EU remains unclear. We reviewed the literature on mortality convergence in the post-2004 EU territory as a whole. We also explored whether the study designs influenced the results and whether any determinants of mortality convergence had been empirically examined. METHODS: A systematic literature review was performed. Our search included scientific databases and the websites of international governmental institutions and European demographic research institutes. RESULTS: We uncovered 94 unique records and included seven studies that reported on 36 analyses. There was marked methodological heterogeneity, including in the convergence measures (beta and sigma convergence). All of the beta convergence analyses found narrowing mortality differentials, whereas most of the sigma convergence analyses found widening mortality differentials. The results are robust to the units of analysis and mortality and dispersion measures. Our results also suggest that there is a lack of evidence on the determinants of mortality convergence in the EU. CONCLUSIONS: There is general agreement that the EU regions and the Member States with high initial mortality rates improved the fastest, but this trend did not lead to overall mortality convergence in the EU. The harmonization of mortality convergence measures and research into determinants of mortality convergence are needed to support future EU cohesion policy. Policy-makers should consider supporting areas that have moderate but stagnant mortality rates, in addition to those with high mortality rates