Asymptotic description of solutions of the exterior Navier Stokes problem in a half space

We consider the problem of a body moving within an incompressible fluid at constant speed parallel to a wall, in an otherwise unbounded domain. This situation is modeled by the incompressible Navier-Stokes equations in an exterior domain in a half space, with appropriate boundary conditions on the wall, the body, and at infinity. We focus on the case where the size of the body is small. We prove in a very general setup that the solution of this problem is unique and we compute a sharp decay rate of the solution far from the moving body and the wall

Electromagnetic properties of graphene junctions

A resonant chiral tunneling (CT) across a graphene junction (GJ) induced by an external electromagnetic field (EF) is studied. Modulation of the electron and hole wavefunction phases $\varphi$ by the external EF during the CT processes strongly impacts the CT directional diagram. Therefore the a.c. transport characteristics of GJs depend on the EF polarization and frequency considerably. The GJ shows great promises for various nanoelectronic applications working in the THz diapason.Comment: 4 pages 3 figure

A century of trends in adult human height

Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5-22.7) and 16.5 cm (13.3-19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8-144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries

Flood risk management approaches: As being practiced in Japan, Netherlands, United Kingdom and United States

Many countries are reassessing their approaches in the face of improved understanding of flood risks. The Japanese Ministry of Land, Infrastructure, Transport and Tourism (MLIT), the Dutch Rijkswaterstaat, the United Kingdom Environment Agency, and the United States Army Corps of Engineers agreed in 2009 to develop a document to explore risk-informed approaches as being practiced and developed primarily in those four countries. Although very different in frequency and scale of flooding as well as cultural and governmental characteristics, each country had significant efforts underway to better orient its practices to flood risk realities, including those induced by altered land use and by climate change and variability. The quadric-lateral collaboration was envisioned as a continuing step in international collaboration and as one means for each country to learn from the other countries\u92 experiences. This document, the result of that collaboration, reflects contributions from agencies within the four participating nations but is not an official position of any government or international organization. The document is organized around a conceptual framework developed to encompass flood risk drivers, risk assessment, and the source-path-receptor concept; the flood risk management cycle with its overarching policies and supporting players and mechanisms; and the adaptive management cycle of maintenance, monitoring, evaluation, and adjustment over time. Differences in scale are addressed through consideration of national and regional/local levels. The document highlights the approaches in each country, the drivers for those approaches, and practices that are working or hold particular promise. Specific examples illustrate various approaches without trying to fully reflect the entirety of any one country\u92s effort or to include an example from each country for any particular aspect