Work function of a quasicrystal surface: Icosahedral Al–Pd–Mn

The work function of a surface is one of its most basic and influential features. It has long been recognized that work function controls thermionic and field emission. The work function of a solid surface affects charge transfer to or from an adsorbate. It influences the electron tunneling probability between surfaces. It plays a role in quantization of electron states parallel to the surface in metal-supported metallic nanoislands. There is also evidence linking the work function of a metal surface to its friction coefficient

Prediction modelling for trauma using comorbidity and 'true' 30-day outcome

BACKGROUND: Prediction models for trauma outcome routinely control for age but there is uncertainty about the need to control for comorbidity and whether the two interact. This paper describes recent revisions to the Trauma Audit and Research Network (TARN) risk adjustment model designed to take account of age and comorbidities. In addition linkage between TARN and the Office of National Statistics (ONS) database allows patient's outcome to be accurately identified up to 30 days after injury. Outcome at discharge within 30 days was previously used. METHODS: Prospectively collected data between 2010 and 2013 from the TARN database were analysed. The data for modelling consisted of 129 786 hospital trauma admissions. Three models were compared using the area under the receiver operating curve (AuROC) for assessing the ability of the models to predict outcome, the Akaike information criteria to measure the quality between models and test for goodness-of-fit and calibration. Model 1 is the current TARN model, Model 2 is Model 1 augmented by a modified Charlson comorbidity index and Model 3 is Model 2 with ONS data on 30 day outcome. RESULTS: The values of the AuROC curve for Model 1 were 0.896 (95% CI 0.893 to 0.899), for Model 2 were 0.904 (0.900 to 0.907) and for Model 3 0.897 (0.896 to 0.902). No significant interaction was found between age and comorbidity in Model 2 or in Model 3. CONCLUSIONS: The new model includes comorbidity and this has improved outcome prediction. There was no interaction between age and comorbidity, suggesting that both independently increase vulnerability to mortality after injury

A maximum density rule for surfaces of quasicrystals

A rule due to Bravais of wide validity for crystals is that their surfaces correspond to the densest planes of atoms in the bulk of the material. Comparing a theoretical model of i-AlPdMn with experimental results, we find that this correspondence breaks down and that surfaces parallel to the densest planes in the bulk are not the most stable, i.e. they are not so-called bulk terminations. The correspondence can be restored by recognizing that there is a contribution to the surface not just from one geometrical plane but from a layer of stacked atoms, possibly containing more than one plane. We find that not only does the stability of high-symmetry surfaces match the density of the corresponding layer-like bulk terminations but the exact spacings between surface terraces and their degree of pittedness may be determined by a simple analysis of the density of layers predicted by the bulk geometric model.Comment: 8 pages of ps-file, 3 Figs (jpg

A Convention on Biological Diversity--An Efficient Framework for the Preservation of Life on Earth?

On June 5, 1992, the Convention on Biological Diversity was introduced for signature at the so-called Earth Summit in Rio de Janeiro. The Convention was one of four international agreements proposed at the Earth Summit. The Convention\u27s explicit objectives are to conserve the Earth\u27s biological diversity (or biodiversity ) for future generations, to exploit this biodiversity in a sustainable way and to share the benefits of biodiversity in a fair and equitable manner. Biological diversity is defined as the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are a part

A Convention on Biological Diversity--An Efficient Framework for the Preservation of Life on Earth?

On June 5, 1992, the Convention on Biological Diversity was introduced for signature at the so-called Earth Summit in Rio de Janeiro. The Convention was one of four international agreements proposed at the Earth Summit. The Convention\u27s explicit objectives are to conserve the Earth\u27s biological diversity (or biodiversity ) for future generations, to exploit this biodiversity in a sustainable way and to share the benefits of biodiversity in a fair and equitable manner. Biological diversity is defined as the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are a part

A Data-Based Console Logger for Mission Operations Team Coordination

Concepts and prototypes1,2 are discussed for a data-based console logger (D-Logger) to meet new challenges for coordination among flight controllers arising from new exploration mission concepts. The challenges include communication delays, increased crew autonomy, multiple concurrent missions, reduced-size flight support teams that include multidisciplinary flight controllers during quiescent periods, and migrating some flight support activities to flight controller offices. A spiral development approach has been adopted, making simple, but useful functions available early and adding more extensive support later. Evaluations have guided the development of the D-Logger from the beginning and continue to provide valuable user influence about upcoming requirements. D-Logger is part of a suite of tools designed to support future operations personnel and crew. While these tools can be used independently, when used together, they provide yet another level of support by interacting with one another. Recommendations are offered for the development of similar projects

The discursive construction of childhood and youth in AIDS interventions in Lesotho's education sector: Beyond global-local dichotomies

This is the post-print version of this article. The definitive, peer-reviewed and edited version of this article is published in Environment and Planning D,Society and Space 28(5) 791 – 810, 2010, available from the link below. Copyright @ 2010 Pion.In southern Africa interventions to halt the spread of AIDS and address its social impacts are commonly targeted at young people, in many cases through the education sector. In Lesotho, education-sector responses to AIDS are the product of negotiation between a range of ‘local’ and ‘global’ actors. Although many interventions are put forward as government policy and implemented by teachers in schools, funding is often provided by bilateral and multilateral donors, and the international ‘AIDS industry’—in the form of UN agencies and international NGOs—sets agendas and makes prescriptions. This paper analyses interviews conducted with policy makers and practitioners in Lesotho and a variety of documents, critically examining the discourses of childhood and youth that are mobilised in producing changes in education policy and practice to address AIDS. Focusing on bursary schemes, life-skills education, and rights-based approaches, the paper concludes that, although dominant ‘global’ discourses are readily identified, they are not simply imported wholesale from the West, but rather are transformed through the organisations and personnel involved in designing and implementing interventions. Nonetheless, the connections through which these discourses are made, and children are subjectified, are central to the power dynamics of neoliberal globalisation. Although the representations of childhood and youth produced through the interventions are hybrid products of local and global discourses, the power relations underlying them are such that they, often unintentionally, serve a neoliberal agenda by depicting young people as individuals in need of saving, of developing personal autonomy, or of exercising individual rights.RGS-IB

Evaporite sinkholes of the Friuli Venezia Giulia region (NE Italy)

Sinkholes are common in the Friuli Venezia Giulia (FVG) Region (NE Italy), where the presence of karstifiable rocks favours their occurrence accelerated by intense rainfalls. Their existence has been reported since the end of the 1800s along the Tagliamento Valley, in correspondence with the mantled evaporites (gypsum). Furthermore, tens of evaporite sinkholes have been documented on the reliefs adjacent to the village of Sauris and along the narrow W\u2013Eoriented valleys, where regional faults have played a major role in their spatial distribution. This paper reports for the first time an inventory of the sinkholes affecting the evaporites of the FVG Region. These phenomena were mapped and categorised using a genetic classification. The main output is an A0-format map, which incorporates a 1:50,000 scale Sinkhole Inventory Map (SIM). The SIM encompasses 552 sinkholes. The cover suffosion sinkholes are the most abundant, followed by bedrock collapses. There is a clear prevalence of the circular shape (65%) over other shapes. Diameters are 1\u2013140 m, with depths ranging 0.1\u201340 m with a mean value of 4.5 m. The SIM can motivate regional planning authorities to perform further investigations aimed to understand the geomorphological evolutions of these phenomena