A TEM, STEM and backscattered electron channeling imaging study of martensite formation in Co-19.6Fe

A high purity, C-free Co-19.6Fe alloy is shown to undergo a variety of martensitic and bainitic reactions. TEM, STEM and back-scattered electron channelling patterns and images have been used to study the effects of ageing at temperatures below the α solvus and of grain boundary misorientation on the occurrence of martensitic transformation in the adjacent grains and on the nature of their product

The construction of the risk of falling among and by older people

Risk is frequently invoked in contemporary accounts of ill health, but its construction is often constrained by a rationalist perspective that focuses on physical causes and functional outcomes, and that presents risk as external to the self and predictable. This paper describes an empirical study of the ways in which risk was realised and managed in a day hospital for older people. An ethnographic approach, with participant observation and semi-structured interviews, and discourse analysis were used to explore these issues with the staff and fifteen users. Whilst the service providers were orientated to the management of physical risk, as through the regimes for administering medication and their attention to risk reduction in the physical environment, the service users were more concerned with the risk to their personal and social identities, and they more frequently described its manifestations in inter-personal exchanges, sometimes as infantalisation and stereotyping. The paper develops this understanding of the potential for falls among older people to elucidate a broader interpretation of risk, and reveals that it is commonly constructed as a challenge to a person's self-image and identity. Such constructions help to explain older people's responses to complex health problems and to the services and treatments that attempt to solve them

Electron cloud observations at the ISIS Proton Synchrotron

The build up of electron clouds inside a particle accelerator vacuum chamber can produce strong transverse and longitudinal beam instabilities which in turn can lead to high levels of beam loss often requiring the accelerator to be run below its design specification. To study the behaviour of electron clouds at the ISIS Proton Synchrotron, a Micro-Channel Plate (MCP) based electron cloud detector has been developed. The detector is based on the Retarding Field Analyser (RFA) design and consists of a retarding grid, which allows energy analysis of the electron signal, and a MCP assembly placed in front of the collector plate. The MCP assembly provides a current gain over the range 300 to 25K, thereby increasing the signal to noise ratio and dynamic range of the measurements. This paper presents the first electron cloud observations at the ISIS Proton Synchrotron. These results are compared against signals from a beam position monitor and a fast beam loss monitor installed at the same location.Comment: 4 pages, contribution to the Joint INFN-CERN-EuCARD-AccNet Workshop on Electron-Cloud Effects: ECLOUD'12; 5-9 Jun 2012, La Biodola, Isola d'Elba, Ital

On the general position subset selection problem

Let $f(n,\ell)$ be the maximum integer such that every set of $n$ points in the plane with at most $\ell$ collinear contains a subset of $f(n,\ell)$ points with no three collinear. First we prove that if $\ell \leq O(\sqrt{n})$ then $f(n,\ell)\geq \Omega(\sqrt{\frac{n}{\ln \ell}})$. Second we prove that if $\ell \leq O(n^{(1-\epsilon)/2})$ then $f(n,\ell) \geq \Omega(\sqrt{n\log_\ell n})$, which implies all previously known lower bounds on $f(n,\ell)$ and improves them when $\ell$ is not fixed. A more general problem is to consider subsets with at most $k$ collinear points in a point set with at most $\ell$ collinear. We also prove analogous results in this setting

Reply to "Comment on 'A linear optics implementation of weak values in Hardy's paradox'"

The comment by Lundeen et al. contains two criticisms of our proposal. While we agree that the state-preparation procedure could be replaced by a simpler setup as proposed by the authors of the comment, we do not agree with the authors on their second, and more important point regarding two-particle weak measurements. We believe this to be the result of a misunderstanding of our original paper.Comment: 2 pages, accepted in PR