Monodisperse Dry Granular Flows on Inclined Planes : Role of Roughness

Recent studies have pointed out the importance of the basal friction on the dynamics of granular flows. We present experimental results on the influence of the roughness of the inclined plane on the dynamics of a monodisperse dry granular flow. We found experimentally that it exists a maximum of the friction for a given relative roughness. This maximum is shown to be independent of the angle of the slope. This behavior is observed for four planes with different bump sizes (given by the size of the beads glued on the plane) from 200 microns to 2 mm. The relative roughness corresponding to the maximum of the friction can be predicted with a geometrical model of stability of one single bead on the plane. The main parameters are the size of the bumps and the size of the flowing beads. In order to obtain a higher precision, the model also takes into account of the spacing between the bumps of the rough plane. Experimental results and model are in good agreement for all the planes we studied. Other parameters, like the sphericity of the beads, or irregularities in the thickness of the layer of glued particles, are shown to be of influence on the friction.Comment: 17 pages, 15 figures, submitted to EPJ

Multi-Layered Roles of Religion among Refugees Arriving in Austria around 2015

Violent conflicts and social unrest in the Middle East, in Central Asia, and in Africa have led to growing numbers of persons seeking refuge in Europe since 2011. The phenomenon culminated in 2015. In that year, with 88,300 new asylum applications, Austria was the 4th largest receiver of asylum seekers in the EU, thereby increasing visibly religious diversity in the country. Using two social surveys carried out in 2015 and in 2017 among asylum seekers and refugees, we study religious affiliation, religiosity, and attitudes as well as participation in religious groups. By focusing on the time span shortly after arriving in Austria, we aim to shed light on first steps in the host society and the multi-layered roles of religion for participation and integration. We provide a comparison with the host society in terms of religious affiliation and religiosity, and discuss recent qualitative research on refugees and religiosity. Insights into the engagement of refugees in several activities related to religion or not are valuable to shed light on the multi-layered characteristics of the recent inflow of forced migrants in Austria

Projection of Populations by Level of Educational Attainment, Age and Sex for 120 Countries for 2005-2050

Using demographic multi-state methods, this paper presents projections for the population of 120 countries (covering 93 percent of the world population in 2000) by age, sex and level of educational attainment for the years 2000 to 2050. The dataset produced gives the full educational attainment distributions for four categories (no education, primary, secondary and tertiary education) by five-year age groups, with definitions that are consistent with a previous reconstruction of educational attainment for the years 1970 to 2000. Based on empirical distributions of educational attainment by age and sex for the year 2000, the method moves along cohort lines while taking into account differentials in fertility and mortality by education level. The most extensive in time and geographical coverage to date, to our knowledge this work represents the first attempt to project future educational attainment trends based on a statistical model of historical international attainment growth. The resulting dataset provides valuable insights both on the feasibility of international education targets and on their implications for human capital and population size and age structure

Evolution in prostheses for sprinters with lower-limb amputation

Depuis une quinzaine d'années, les progrès techniques en appareillage ont été le facteur déterminant de la progression des performances des sportifs amputés de membre inférieur. Pour l'amputé tibial, la prothèse de course comprend un manchon gel et une emboîture solidarisés par un accrochage distal ou un vide virtuel. Par ses qualités dynamiques, le pied en fibre de carbone, garni de pointes, assure des performances remarquables. Pour l'amputé fémoral, équipé des mêmes pieds prothétiques, le genou est à biellettes et à contrôle des phases d'appui et pendulaire. Par rapport au coureur valide, le temps d'appui sur le membre appareillé est raccourci tandis que celui sur le membre sain est allongé. L'asymétrie du sprint de l'amputé tibial est discrète. C'est le travail des extenseurs de hanche qui est la principale compensation au déficit de propulsion dû à l'amputation. Chez l'amputé fémoral, l'absence de genou aggrave l'asymétrie. L'extension totale du genou prothétique, précoce en fin de phase oscillante et persistant pendant toute la phase d'appui, impose une compensation par une augmentation d'extension de la hanche controlatérale. Les transferts de charge de travail entre côté amputé et sain, par l'intermédiaire d'une hyperlordose lombaire, mettent en jeu le bassin, le tronc et les épaules. Les amputés sportifs font progresser la recherche en appareillage. Leurs orthoprothésistes acquièrent avec eux un savoir-faire dont bénéficient leurs patients non-sportifs.For about 15 years, technical advances in prosthetic treatment have been the main factor in the increased performance of athletes with lower-limb amputation. For trans-tibial amputation, the prosthesis for sprinting is composed of a gel liner and a socket joined by a locking or virtual vacuum liner. Because of these dynamic properties, the carbon prosthetic foot equipped with tacks ensures outstanding performance. For trans-femoral amputation, a hydraulic swing and a stance control unit are added to the same prosthesis. In comparison with the able-bodied runner, athletes with amputation have smaller loading times in the prosthetic limb and larger ones in the sound limb. The length of the energy-storing prosthetic foot is determined by the “up-on-the-toes” running gait. The sprinting gait with trans-tibial amputation is almost symmetrical. The hip extensor effort is the main compensation of propulsion reduction with lower-limb amputation. With trans-femoral amputation, the lack of knee increases the asymmetry. The total prosthetic knee extension (early in late-swing phase and lasting during total stance phase) compensates with extension of both hips, especially the opposite one. The amputation and sound limb load transfer with lumbar hyperlordosis concern the pelvis, trunk and shoulders. Because of athletes with amputation, research in prosthetic treatment has progressed. The development of orthotics and prostheses for such athletes has benefited non-athletes with amputation

Projection of populations by level of educational attainment, age, and sex for 120 countries for 2005-2050

Using demographic multi-state, cohort-component methods, we produce projections for 120 countries (covering 93% of the world population in 2005) by five-year age groups, sex, and four levels of educational attainment for the years 2005-2050. Taking into account differentials in fertility and mortality by education level, we present the first systematic global educational attainment projections according to four widely differing education scenarios. The results show the possible range of future educational attainment trends around the world, thereby contributing to long-term economic and social planning at the national and international levels, and to the assessment of the feasibility of international education goals

PHARAO Laser Source Flight Model: Design and Performances

In this paper, we describe the design and the main performances of the PHARAO laser source flight model. PHARAO is a laser cooled cesium clock specially designed for operation in space and the laser source is one of the main sub-systems. The flight model presented in this work is the first remote-controlled laser system designed for spaceborne cold atom manipulation. The main challenges arise from mechanical compatibility with space constraints, which impose a high level of compactness, a low electric power consumption, a wide range of operating temperature and a vacuum environment. We describe the main functions of the laser source and give an overview of the main technologies developed for this instrument. We present some results of the qualification process. The characteristics of the laser source flight model, and their impact on the clock performances, have been verified in operational conditions.Comment: Accepted for publication in Review of Scientific Instrument

A Harmonized Dataset on Global Educational Attainment between 1970 and 2060 – An Analytical Window into Recent Trends and Future Prospects in Human Capital Development

We hereby present a dataset produced at the Wittgenstein Centre (WIC) containing comprehensive time series on educational attainment and mean years of schooling (MYS). The dataset is split by 5-year age groups and sex for 171 countries and covers the period between 1970 and 2010. It also contains projections of educational attainment to 2060 based on several scenarios of demographic and educational development. The dataset is constructed around collected and harmonized empirical census and survey data sets for the projection base year. The paper presents the principles and methodology associated with the reconstruction and the projection, and how it differs from several previous exercises. It also proposes a closer look at the diffusion of education in world regions and how the existing gaps in terms of generation, gender, and geography have been evolving in the last 40 years

Immigrants' educational attainment: A mixed picture, but often higher than the average in their country of origin

The immigrants living in France and the refugees who arrived in Austria are more educated than most of the population in their country of origin. By comparison with the population in the host country, the picture is more mixed: some groups, such as immigrants from Portugal living in France, are relatively low educated, while others, such as Romanians, have more frequently completed higher education than people born in France