Peeling from a patterned thin elastic film

Inspired by the observation that many naturally occurring adhesives arise as textured thin films, we consider the displacement controlled peeling of a flexible plate from an incision-patterned thin adhesive elastic layer. We find that crack initiation from an incision on the film occurs at a load much higher than that required to propagate it on a smooth adhesive surface; multiple incisions thus cause the crack to propagate intermittently. Microscopically, this mode of crack initiation and propagation in geometrically confined thin adhesive films is related to the nucleation of cavitation bubbles behind the incision which must grow and coalesce before a viable crack propagates. Our theoretical analysis allows us to rationalize these experimental observations qualitatively and quantitatively and suggests a simple design criterion for increasing the interfacial fracture toughness of adhesive films.Comment: 8 pages, To appear in Proceedings of Royal Society London, Ser.

Physical activity among 60-69-year-olds in England: knowledge, perception, behaviour and risk factors

This paper examines the risk factors that influence physical activity levels among a representative sample or older people in England and their awareness of the Chief Medical Officer's recommended level of physical activity. The paper analyses data from the cross-sectional, nationally-representative Health Surveys for England (HSfE) in 2006 and 2007. In HSfE2006, 1,550 adults aged 60-69 years responded to a physical activity participation questionnaire, and in HSfE2007, 561 adults aged 60-64. years were asked about their knowledge of the physical activity requirement and their attitudes to participation. Very few respondents knew the recommended physical activity target, but more than one-half thought they had enough physical activity in their daily life, and over three-quarters thought they were 'very' or 'fairly' physically active compared with age peers. The perceived barriers to physical activity included work commitments, lack of leisure time and poor health. It was found that obesity, not being in work and having a limiting long-term illness associated with a lower likelihood of physical activity. Participation in sports and exercise, walking, heavy housework and gardening were all lower in non-working than working adults. Older adults had unrealistic views of their activity levels, and of work and lack of time as barriers to physical activity. It is concluded that more attention needs to be paid to health promotion and education among the over-sixties, especially those not in paid work

The Market Value and Dynamic Interest Rate Risk of Swaps

At the time of initiation, interest rate swaps are of zero market value to the counterparties involved. However, as time passes, the market value of the swap position of each counterpart may become positive or negative. These value changes are stochastic in nature and are primarily driven by stochastic variations of the term structure of interest rates. In this paper, we develop models for determining the market values and dynamic interest rate risks of existing swap positions using the one-factor general equilibrium term structure model of Cox, Ingersoll, and Ross (1985). The valuation and risk measurement framework of this paper should be useful in developing a value turn risk accounting method advocated by Merton and Bodie (1995) for better internal management and reporting purposes and for more effective regulation. This paper was presented at the Financial Institutions Center's October 1996 conference on "

Quantum Control of the Hyperfine Spin of a Cs Atom Ensemble

We demonstrate quantum control of a large spin-angular momentum associated with the F=3 hyperfine ground state of 133Cs. A combination of time dependent magnetic fields and a static tensor light shift is used to implement near-optimal controls and map a fiducial state to a broad range of target states, with yields in the range 0.8-0.9. Squeezed states are produced also by an adiabatic scheme that is more robust against errors. Universal control facilitates the encoding and manipulation of qubits and qudits in atomic ground states, and may lead to improvement of some precision measurements.Comment: 4 pages, 4 figures (color

Synthesis and reactivity of tricarbonyl(1-methoxycarbonyl-5-phenylpentadienyl)iron(1+) cation

Tricarbonyl(1-methoxycarbonyl-5-phenylpentadienyl)iron(1+) hexafluorophosphate (7) was prepared in two steps from tricarbonyl(methyl 6-oxo-2,4-hexadienoate)iron. While addition of carbon and heteroatom nucleophiles to 7 generally occurs at the phenyl-substituted dienyl carbon to afford (2,4-dienoate)iron products, the addition of phthalimide proceeded at C2 to afford a (pentenediyl)iron product (18). Complex 18 was structurally characterized by X-ray diffraction analysis. The reaction of the title cation with carbon and heteroatom nucleophiles was examined. In general, the products arise from nucleophilic attack at C5 to give E,E- or E,Z-dienoate iron complexes. Addition of phthalimide anion proceeds at C2 of the cation to afford a (pentenediyl)iron complex, whose structure was confirmed by X-ray diffraction analysis

Participatory gender-sensitive approaches for addressing key climate change- related research issues: Evidence from Bangladesh, Ghana, and Uganda

Getting a better understanding of how climate variability affects rural men and women differently, and in different regions, is challenging. Since their ability to respond to change and take action that will make them more resilient and able to adapt to a changing climate (alongside all the other social and economic change they are dealing with) differs, we need to focus more research efforts on enhancing this understanding and linking this knowledge with actions aimed at enhancing livelihoods and food security. We examine how well existing participatory gender-sensitive research approaches address some key climate change-related research issues that CCAFS has prioritized. Bringing together gender experts and experienced agricultural research teams from Bangladesh, Ghana, and Uganda, multiple methods were tested in the field, and refined through the lessons learned, to help inform future action research and development efforts towards enhancing communities’ and individuals’ (particularly women’s) access to, and use of, information and knowledge to help them adapt to climate variability through more resilient livelihoods and agro-ecosystems

Magnetoelectric Effect and Spontaneous Polarization in HoFe3_3(BO3_3)4_4 and Ho0.5_{0.5}Nd0.5_{0.5}Fe3_3(BO3_3)4_4

The thermodynamic, magnetic, dielectric, and magnetoelectric properties of HoFe$_3$(BO$_3$)$_4$ and Ho$_{0.5}$Nd$_{0.5}$Fe$_3$(BO$_3$)$_4$ are investigated. Both compounds show a second order Ne\'{e}l transition above 30 K and a first order spin reorientation transition below 10 K. HoFe$_3$(BO$_3$)$_4$ develops a spontaneous electrical polarization below the Ne\'{e}l temperature (T$_N$) which is diminished in external magnetic fields. No magnetoelectric effect could be observed in HoFe$_3$(BO$_3$)$_4$. In contrast, the solid solution Ho$_{0.5}$Nd$_{0.5}$Fe$_3$(BO$_3$)$_4$ exhibits both, a spontaneous polarization below T$_N$ and a magnetoelectric effect at higher fields that extends to high temperatures. The superposition of spontaneous polarization, induced by the internal magnetic field in the ordered state, and the magnetoelectric polarizations due to the external field results in a complex behavior of the total polarization measured as a function of temperature and field.Comment: 12 pages, 15 figure

Using a gender lens to explore farmers’ adaptation options in the face of climate change: Results of a pilot study in Uganda

Uganda, and especially the Rakai district, is highly vulnerable to climate variability and likely to be amongst the worst hit under climate change. Any responses to climate change affected communities cannot be considered complete unless women-specific responses are interwoven in a variety of adaptation options considered in the target area. The overall objective of this short-term research was to test tools and methodologies developed by CCAFS, FAO on analysis of gender issues in climate change, agriculture and food security. The study took place from the 1–4 November 2011, in the village of Kyengeza village in Uganda