Secrecy and Group Creation

AbstractWe add an operation of group creation to the typed pi-calculus, where a group is a type for channels. Creation of fresh groups has the effect of statically preventing certain communications, and can block the accidental or malicious leakage of secrets. We adapt a notion of secrecy introduced by Abadi, and prove a preservation of secrecy property. When applied to the ambient calculus, the same notion of group creation can be used to create and preserve shared secrets among mobile agents

New Chronology for the Welsh Hillfort of Dinas Powys

Acknowledgements The laser scan of Dinas Powys was undertaken by Cotswold Archaeology. We would also like to thank Jeremy Knight, Anna Bloxam, Mark Lodwick, and Amgueddfa Cymru National Museum Wales. Funding statement Dates for Bank 1 were partly funded by the Leverhulme Trust Comparative Kingship project (RL-2016-069).Peer reviewedPostprin

Environmental Impacts of the Border Wall

On January 25, 2017, during his first week in office, President Donald Trump signed an Executive Order calling for the “immediate construction of a physical wall on the southern border” of the United States . Such a wall would span more than one thousand miles, across many different habitats and many different communities . Before a wall will be built, numerous questions must be answered: Which environmental laws apply? How might all this work? On February 16, ELI convened experts to discuss how environmental law and policy may interact with the Executive Order, and to spark discussion about important environmental resources and communities along the border . Below, we present a transcript of the event, which has been edited for style, clarity, and space considerations

Council tax valuation band predicts breast feeding and socio-economic status in the ALSPAC study population

BACKGROUND: Breast-feeding rates in the UK are known to vary by maternal socio-economic status but the latter function is imperfectly defined. We test if CTVB (Council Tax Valuation Band – a categorical assessment of UK property values and amenities governing local tax levies) of maternal address predicts, in a large UK regional sample of births, (a) breast-feeding (b) personal and socio-economic attributes of the mothers. METHODS: Retrospective study of a subset (n.1390 selected at random) of the ALSPAC sample (Avon Longitudinal Study of Parents and Children), a large, geographically defined cohort of mothers followed from early pregnancy to 8 weeks post-delivery. Outcome measures are attitudes to breast-feeding prior to delivery, breast-feeding intention and uptake, demographic and socio-economic attributes of the mothers, CTVB of maternal home address at the time of each birth. Logistic regression analysis, categorical tests. RESULTS: Study sample: 1360 women divided across the CTVBs – at least 155 in any band or band aggregation. CTVB predicted only one belief or attitude – that bottle-feeding was more convenient for the mother. However only 31% of 'CTVB A infants' are fully breast fed at 4 weeks of life whereas for 'CTVB E+ infants' the rate is 57%. CTVB is also strongly associated with maternal social class, home conditions, parental educational attainment, family income and smoking habit. CONCLUSION: CTVB predicts breast-feeding rates and links them with social circumstances. CTVB could be used as the basis for accurate resource allocation for community paediatric services: UK breast-feeding rates are low and merit targeted promotion

Centre of rotation of the human subtalar joint using weight-bearing clinical computed tomography

Accurate in vivo quantification of subtalar joint kinematics can provide important information for the clinical evaluation of subtalar joint function; the analysis of outcome of surgical procedures of the hindfoot; and the design of a replacement subtalar joint prosthesis. The objective of the current study was to explore the potential of full weight-bearing clinical computed tomography (CT) to evaluate the helical axis and centre of rotation of the subtalar joint during inversion and eversion motion. A subject specific methodology was proposed for the definition of the subtalar joint motion combining three-dimensional (3D) weight-bearing imaging at different joint positions with digital volume correlation (DVC). The computed subtalar joint helical axis parameters showed consistency across all healthy subjects and in line with previous data under simulated loads. A sphere fitting approach was introduced for the computation of subtalar joint centre of rotation, which allows to demonstrate that this centre of rotation is located in the middle facet of the subtalar joint. Some translation along the helical axis was also observed, reflecting the elasticity of the soft-tissue restraints. This study showed a novel technique for non-invasive quantitative analysis of bone-to-bone motion under full weight-bearing of the hindfoot. Identifying different joint kinematics in patients with ligamentous laxity and instability, or in the presence of stiffness and arthritis, could help clinicians to define optimal patient-specific treatments