The ALE-method with triangular elements: direct convection of integration point values

The arbitrary Lagrangian-Eulerian (ALE) finite element method is applied to the simulation of forming processes where material is highly deformed. Here, the split formulation is used: a Lagrangian step is done with an implicit finite element formulation, followed by an explicit (purely convective) Eulerian step. The purpose of this study is to investigate the Eulerian step for quadratic triangular elements. To solve the convection equation for integration point values, a new method inspired by Van Leer is constructed. The new method is based on direct convection of integration point values without intervention of nodal point values.\ud The Molenkamp test and a so-called block test were executed to check the performance and stability of the convection scheme. From these tests it is concluded that the new convection scheme shows accurate results. The scheme is extended to an ALE-algorithm. An extrusion process was simulated to test the applicability of the scheme to engineering problems. It is concluded that direct convection of integration point values with the presented algorithm leads to accurate results and that it can be applied to ALE-simulation

Computer tomography colonography participation and yield in patients under surveillance for 6-9 mm polyps in a population-based screening trial

Purpose: Surveillance CT colonography (CTC) is a viable option for 6-9 mm polyps at CTC screening for colorectal cancer. We established participation and diagnostic yield of surveillance and determined overall yield of CTC screening. Material and methods: In an invitational CTC screening trial 82 of 982 participants harboured 6-9 mm polyps as the largest lesion(s) for which surveillance CTC was advised. Only participants with one or more lesion(s) ≥6 mm at surveillance CTC were offered colonoscopy (OC); 13 had undergone preliminary OC. The surveillance CTC yield was defined as the number of participants with advanced neoplasia in the 82 surveillance participants, and was added to the primary screening yield. Results: Sixty-five of 82 participants were eligible for surveillance CTC of which 56 (86.2 %) participated. Advanced neoplasia was diagnosed in 15/56 participants (26.8 %) and 9/13 (69.2 %) with preliminary OC. Total surveillance yield was 24/82 (29.3 %). No carcinomas were detected. Adding surveillance results to initial screening CTC yield significantly increased the advanced neoplasia yield per 100 CTC participants (6.1 to 8.6; p < 0.001) and per 100 invitees (2.1 to 2.9; p < 0.001). Conclusion: Surveillance CTC for 6-9 mm polyps has a substantial yield of advanced adenomas and significantly increased the CTC yield in population screening. Key Points: • The participation rate in surveillance CT colonography (CTC) is 86 %. • Advanced adenoma prevalence in a 6-9 mm CTC surveillance population is high. • Surveillance CTC significantly increases the yield of population screening by CTC. • Surveillance CTC for 6-9 mm polyps is a safe strategy. • Sur

Interconnecting Governments, Businesses and Citizens – A Comparison of Two Digital Infrastructures

Part 2: Services and InteroperabilityInternational audiencePublic and private organizations in various areas are setting up digital Information Infrastructures (IIs) for interconnecting government, businesses and citizens. IIs can create value by sharing and integrating data of multiple actors. This can be the basis for value added services and especially collaborations of public and private partners can make IIs thrive. Easier access to integrated services and products (jointly) offered by government and businesses may stimulate transparency and innovations. IIs are under development in many domains, including for open data and international trade. However, there are notable differences in the design, characteristics and implementation of the IIs. The objective of this paper is to compare two diverse IIs in order to obtain a better understanding of common and differing elements in the IIs and their impact. Among the differences are the roles of government, businesses and users, in driving, developing and exploitation of the IIs

State of the field: What can political ethnography tell us about anti-politics and democratic disaffection?

This article adopts and reinvents the ethnographic approach to uncover what governing elites do, and how they respond to public disaffection. Although there is significant work on the citizens’ attitudes to the governing elite (the demand side) there is little work on how elites interpret and respond to public disaffection (the supply side). We argue that ethnography is the best available research method for collecting data on the supply side. In doing so, we tackle long-standing stereotypes in political science about the ethnographic method and what it is good for. We highlight how the innovative and varied practices of contemporary ethnography are ideally suited to shedding light into the ‘black box’ of elite politics. We demonstrate the potential pay-off with reference to important examples of elite ethnography from the margins of political science scholarship. The implications from these rich studies, we argue, suggest a reorientation of how we understand the drivers of public disaffection and the role that political elites play in exacerbating cynicism and disappointment. We conclude by pointing to the benefits to the discipline in embracing elite ethnography both to diversify the methodological toolkit in explaining the complex dynamics of disaffection,and to better enable engagement in renewed public debate about the political establishment

A place-based approach to payments for ecosystem services

Payment for Ecosystem Services (PES) schemes are proliferating but are challenged by insufficient attention to spatial and temporal inter-dependencies, interactions between different ecosystems and their services, and the need for multi-level governance. To address these challenges, this paper develops a place-based approach to the development and implementation of PES schemes that incorporates multi-level governance, bundling or layering of services across multiple scales, and shared values for ecosystem services. The approach is evaluated and illustrated using case study research to develop an explicitly place-based PES scheme, the Peatland Code, owned and managed by the International Union for the Conservation of Nature’s UK Peatland Programme and designed to pay for restoration of peatland habitats. Buyers preferred bundled schemes with premium pricing of a primary service, contrasting with sellers’ preferences for quantifying and marketing services separately in a layered scheme. There was limited awareness among key business sectors of dependencies on ecosystem services, or the risks and opportunities arising from their management. Companies with financial links to peatlands or a strong environmental sustainability focus were interested in the scheme, particularly in relation to climate regulation, water quality, biodiversity and flood risk mitigation benefits. Visitors were most interested in donating to projects that benefited wildlife and were willing to donate around £2 on-site during a visit. Sellers agreed a deliberated fair price per tonne of CO2 equivalent from £11.18 to £15.65 across four sites in Scotland, with this range primarily driven by spatial variation in habitat degradation. In the Peak District, perceived declines in sheep and grouse productivity arising from ditch blocking led to substantially higher prices, but in other regions ditch blocking was viewed more positively. The Peatland Code was developed in close collaboration with stakeholders at catchment, landscape and national scales, enabling multi-level governance of the management and delivery of ecosystem services across these scales. Place-based PES schemes can mitigate negative trade-offs between ecosystem services, more effectively include cultural ecosystem services and engage with and empower diverse stakeholders in scheme design and governance

Scientific rationale for Uranus and Neptune <i>in situ</i> explorations

The ice giants Uranus and Neptune are the least understood class of planets in our solar system but the most frequently observed type of exoplanets. Presumed to have a small rocky core, a deep interior comprising ∼70% heavy elements surrounded by a more dilute outer envelope of H2 and He, Uranus and Neptune are fundamentally different from the better-explored gas giants Jupiter and Saturn. Because of the lack of dedicated exploration missions, our knowledge of the composition and atmospheric processes of these distant worlds is primarily derived from remote sensing from Earth-based observatories and space telescopes. As a result, Uranus's and Neptune's physical and atmospheric properties remain poorly constrained and their roles in the evolution of the Solar System not well understood. Exploration of an ice giant system is therefore a high-priority science objective as these systems (including the magnetosphere, satellites, rings, atmosphere, and interior) challenge our understanding of planetary formation and evolution. Here we describe the main scientific goals to be addressed by a future in situ exploration of an ice giant. An atmospheric entry probe targeting the 10-bar level, about 5 scale heights beneath the tropopause, would yield insight into two broad themes: i) the formation history of the ice giants and, in a broader extent, that of the Solar System, and ii) the processes at play in planetary atmospheres. The probe would descend under parachute to measure composition, structure, and dynamics, with data returned to Earth using a Carrier Relay Spacecraft as a relay station. In addition, possible mission concepts and partnerships are presented, and a strawman ice-giant probe payload is described. An ice-giant atmospheric probe could represent a significant ESA contribution to a future NASA ice-giant flagship mission

A search for the decay B+→K+ννˉB^+ \to K^+ \nu \bar{\nu}

We search for the rare flavor-changing neutral-current decay $B^+ \to K^+ \nu \bar{\nu}$ in a data sample of 82 fb$^{-1}$ collected with the {\sl BABAR} detector at the PEP-II B-factory. Signal events are selected by examining the properties of the system recoiling against either a reconstructed hadronic or semileptonic charged-B decay. Using these two independent samples we obtain a combined limit of ${\mathcal B}(B^+ \to K^+ \nu \bar{\nu})<5.2 \times 10^{-5}$ at the 90% confidence level. In addition, by selecting for pions rather than kaons, we obtain a limit of ${\mathcal B}(B^+ \to \pi^+ \nu \bar{\nu})<1.0 \times 10^{-4}$ using only the hadronic B reconstruction method.Comment: 7 pages, 8 postscript figures, submitted to Phys. Rev. Let

High-reflectivity broadband distributed Bragg reflector lattice matched to ZnTe

We report on the realization of a high quality distributed Bragg reflector with both high and low refractive index layers lattice matched to ZnTe. Our structure is grown by molecular beam epitaxy and is based on binary compounds only. The high refractive index layer is made of ZnTe, while the low index material is made of a short period triple superlattice containing MgSe, MgTe, and ZnTe. The high refractive index step of Delta_n=0.5 in the structure results in a broad stopband and the reflectivity coefficient exceeding 99% for only 15 Bragg pairs.Comment: 4 pages, 3 figure