Fast solution of Cahn-Hilliard variational inequalities using implicit time discretization and finite elements

We consider the e�cient solution of the Cahn-Hilliard variational inequality using an implicit time discretization, which is formulated as an optimal control problem with pointwise constraints on the control. By applying a semi-smooth Newton method combined with a Moreau-Yosida regularization technique for handling the control constraints we show superlinear convergence in function space. At the heart of this method lies the solution of large and sparse linear systems for which we propose the use of preconditioned Krylov subspace solvers using an e�ective Schur complement approximation. Numerical results illustrate the competitiveness of this approach

Diffusion of collaborative maps about accessibility

Recently, neogeography projects focused on collaborative mapping of localized accessibility knowledge have resulted in applications that are designed to collect ratings of how accessible certain venues (e.g., buildings) are for people who travel in wheelchairs, people with low to no hearing or vision and older adults. Each application is the product of different creators, yet there are striking similarities in their purpose and features. These applications are crowdsourcing systems for information sharing that allow users to add meaningful information to a personalized web map; however, little research has analyzed how these applications have been created and adopted overtime. This paper reviews several existing applications and presents a framework for analyzing their diffusion over time

Ontology of accessibility in the context of wayfinding for people with disabilities.

There is evidence that objects in and of the built environment function as barriers or facilitators to accessibility for people with disabilities. Although there are many existing sources of information about accessibility, they often lack clear criteria to describe accessibility, explanations of barriers and facilitators to mobility, and coverage of multiple physical environments. Researchers have argued that wayfinding services (e.g., Google Maps) can help people with disabilities prepare to travel through the built environment, yet current wayfinding services include little to no information about accessibility. This dissertation aims to study accessibility, in the context of wayfinding, in indoor, outdoor and transitional environments for people who travel in wheelchairs and people with low to no vision. To this end, a qualitative ontological analysis of multiple sources of information regarding accessibility was conducted including analyses of important categories associated with accessible wayfinding; different information providers’ views on accessibility; and specific barriers and facilitators to accessibility. The results indicate that (1) people with low to no vision and people who travel in wheelchairs have different core wayfinding information needs, (2) a gap exists between the information people with disabilities and researchers provide on accessibility and that provided by standard guidelines, and (3) conceptualizing accessibility requires capturing actions performed by people with disabilities during every day travel along with characteristics of environmental objects. The resulting ontology could be leveraged to generate new criteria describing accessibility, new routing algorithms, or to attach provenance to existing accessibility criteria. The findings have implications for people who design wayfinding services and collaborative maps and people collaboratively collecting data on the accessibility of specific places

Project Management in Libraries: LIS2971 Summer Course

The growth of projects in libraries is pervasive. This short 1-credit course introduces LIS students to the discipline of project management in a hands-on way, so that they can begin applying project management methods immediately

Peat Formation Concentrates Arsenic Within Sediment Deposits of the Mekong Delta

Mekong River Delta sediment bears arsenic that is released to groundwater under anaerobic conditions over the past several thousand years. The oxidation state, speciation, and distribution of arsenic and the associated iron bearing phases are crucial determinants of As reactivity in sediments. Peat from buried mangrove swamps in particular may be an important host, source, or sink of arsenic in the Mekong Delta. The total concentration, speciation, and reactivity of arsenic and iron were examined in sediments in a Mekong Delta wetland by X-ray fluorescence spectrometry (XRF), X-ray absorption spectroscopy (XAS), and selective chemical extractions. Total solid-phase arsenic concentrations in a peat layer at a depth of 6 m below ground increased 10-fold relative to the overlying sediment. Extended X-ray absorption fine structure (EXAFS) spectroscopy revealed that arsenic in the peat was predominantly in the form of arsenian pyrite. Arsenic speciation in the peat was examined further at the micron-scale using μXRF and μX-ray absorption near-edge structure (XANES) spectroscopy coupled with principal component analysis. The multiple energy μXRF mapping and μXANES routine was repeated for both iron and sulfur phase analyses. Our μXRF/μXANES analyses confirm arsenic association with pyrite – a less reactive host phase than iron (hydr)oxides under anaerobic conditions. The arsenian pyrite likely formed upon deposition/formation of the peat in a past estuarine environment (∼ 5.5 ka BP), a process that is not expected under current geochemical conditions. Presently, arsenian pyrite is neither a source nor a sink for aqueous arsenic in our sediment profile, and under present geochemical conditions represents a stable host of As under the reducing aquifer conditions of the Mekong Delta. Furthermore, organic carbon within the peat is unable to fuel Fe(III) reduction, as noted by the persistence of goethite which can be reduced microbially with the addition of glucose

Supporting Software Preservataion Services in Research and Memory Organizations

Reconnaître la préservation des logiciels comme un problème commun et complexe que chaque organisation ne peut résoudre seul, le Software Preservation Network (SPN) a été lancé en 2016 pour sensibiliser, renforcer les capacités et favoriser les actions collectives qui mobilisent un large éventail d’intervenants qui ont un intérêt dans ce travail

The international generalisability of evidence for health policy: a cross country comparison of medication adherence following policy change

Copayments for prescriptions may increase morbidity and mortality via reductions in adherence to medications. Relevant data can inform policy to minimise such unintended effects. We explored the generalisability of evidence for copayments by comparing two international copayment polices, one in Massachusetts and one in Ireland, to assess whether effects on medication adherence were comparable. We used national prescription data for public health insurance programmes in Ireland and Medicaid data in the U.S. New users of oral anti-hypertensive, anti-hyperlipidaemic and diabetic drugs were included (total n = 14,259 in U.S. and n = 43,843 in Ireland). We examined changes in adherence in intervention and comparator groups in each setting using segmented linear regression with generalised estimating equations. In Massachusetts, a gradual decrease in adherence to anti-hypertensive medications of −1% per month following the policy occurred. In contrast, the response in Ireland was confined to a −2.9% decrease in adherence immediately following the policy, with no further decrease over the 8 month follow-up. Reductions in adherence to oral diabetes drugs were larger in the U.S. group in comparison to the Irish group. No difference in adherence changes between the two settings for anti-hyperlipidaemic drugs occurred. Evidence on cost-sharing for prescription medicines is not ‘one size fits all’. Time since policy implementation and structural differences between health systems may influence the differential impact of copayment policies in international settings