Color television study Final report, Nov. 1965 - Mar. 1966

Color television camera for transmission from lunar and earth orbits and lunar surfac

The Dual Feminisation of HIV/AIDS

This is an Accepted Manuscript of an article published by Taylor & Francis in Globalizations on 2011, available online: http://wwww.tandfonline.com/10.1080/14747731.2010.49302

Polynomial diffeomorphisms of C^2, IV: The measure of maximal entropy and laminar currents

This paper concerns the dynamics of polynomial automorphisms of ${\bf C}^2$. One can associate to such an automorphism two currents $\mu^\pm$ and the equilibrium measure $\mu=\mu^+\wedge\mu^-$. In this paper we study some geometric and dynamical properties of these objects. First, we characterize $\mu$ as the unique measure of maximal entropy. Then we show that the measure $\mu$ has a local product structure and that the currents $\mu^\pm$ have a laminar structure. This allows us to deduce information about periodic points and heteroclinic intersections. For example, we prove that the support of $\mu$ coincides with the closure of the set of saddle points. The methods used combine the pluripotential theory with the theory of non-uniformly hyperbolic dynamical systems

Adding flavour to twistor strings

Twistor string theory is known to describe a wide variety of field theories at tree-level and has proved extremely useful in making substantial progress in perturbative gauge theory. We explore the twistor dual description of a class of N=2 UV-finite super-Yang-Mills theories with fundamental flavour by adding 'flavour' branes to the topological B-model on super-twistor space and comment on the appearance of these objects. Evidence for the correspondence is provided by matching amplitudes on both sides.Comment: 6 pages; contribution to the proceedings for the European Physical Society conference on High Energy Physics in Manchester, 19-25 July 2007. v3: Typos correcte

Characterisation of Float Rocks at Ireson Hill, Gale Crater

Float rocks discovered by surface missions on Mars have given unique insights into the sedimentary, diagenetic and igneous processes that have operated throughout the planets history. In addition, Gale sedimentary rocks, both float and in situ, record a combination of source compositions and diagenetic overprints. We examine a group of float rocks that were identified by the Mars Science Laboratory missions Curiosity rover at the Ireson Hill site, circa. sol 1600 using ChemCam LIBS, APXS and images from the MastCam, Mars Hand Lens Imager (MAHLI) and ChemCam Remote Micro-Imager (RMI) cameras. Geochemical data provided by the APXS and ChemCam instruments allow us to compare the compositions of these rocks to known rock types from Gale crater, as well as elsewhere on Mars. Ireson Hill is a 15 m long butte in the Murray formation with a dark cap-ping unit with chemical and stratigraphic consistency with the Stimson formation. A total of 6 float rocks have been studied on the butte

What is the value of a standard?

Standards play a critical role in the procurement of defence, and other, systems. Choosing the most appropriate standard is important but has become more topical given the UK Ministry of Defence policy of “as civilian as possible, as military as necessary”. Whereas historically managers might have selected from classes of defence standards, this choice set is now increased to include civil standards. We develop a model that has been commissioned by the UK Defence Standardisation whose responsibilities include supporting project teams on the selection of standards. Our model is based on an extension of Bayesian Belief Networks, called an Influence Diagram, which allows decisions and consequences to be represented as well as uncertain-ties. We have developed an initial model for a real case to assess the feasibility and use. We outline the con-text of the defence procurement project in our case study and describe the reasoning underpinning the model structure. We have found that it is possible to develop a simple model that captures the views of multiple stakeholders and informs a reasoned choice about the value of alternative standards

Improving immunization uptake rates among Gypsies, Roma and Travellers: a qualitative study of the views of service providers

BACKGROUND: Gypsies, Roma and Travellers are at risk of low uptake of routine immunizations. Interventions to improve uptake in these communities are seldom evaluated. As part of a qualitative study exploring barriers and facilitators to immunization uptake in Travellers, we report service provider (SP) perspectives. METHODS: We interviewed immunization SPs working with six Traveller communities across four UK cities. Participants included frontline staff and those with strategic or commissioning roles. Semi-structured interviews explored perceived attitudes of Travellers to vaccinations, local service delivery, and opportunities and challenges to improving uptake. Audio-recordings were transcribed, analyzed thematically and mapped to a socio-ecological model of health. RESULTS: 39 SPs participated. Four overarching themes were identified: building trusting relationships between SPs and Travellers; facilitating attendance at appointments; improving record keeping and monitoring and responding to local and national policy change. Travellers were perceived as largely supportive of immunizations, though system and organizational processes were recognized barriers to accessing services. CONCLUSIONS: Findings were broadly consistent across Traveller groups and settings. The barriers identified could often be addressed within existing infrastructure, though require system or policy change. Development of a culturally competent system appears important to enable equity in access to immunizations for Travellers

Exploring Human Papillomavirus Vaccination Refusal Among Ethnic Minorities in England: A Comparative Qualitative Study.

OBJECTIVES: In England, uptake of human papillomavirus (HPV) vaccination to prevent HPV-related cancer is lower among girls from ethnic minority backgrounds. We aimed to explore the factors that prevented ethnic minority parents from vaccinating, compared to White British non-vaccinating parents and vaccinating ethnic minority parents. METHODS: Interviews with 33 parents (n = 14 ethnic minority non-vaccinating, n = 10 White British non-vaccinating, n = 9 ethnic minority vaccinating) explored parents' reasons for giving or withholding consent for HPV vaccination. Data were analysed using Framework Analysis. RESULTS: Concerns about the vaccine were raised by all non-vaccinating ethnic minority parents, and they wanted information to address these concerns. External and internal influences affected parents' decisions, as well as parents' perceptions that HPV could be prevented using means other than vaccination. Reasons were not always exclusive to non-vaccinating ethnic minority parents, although some were, including a preference for abstinence from sex before marriage. Only ethnic minority parents wanted information provided via workshops. CONCLUSIONS: Ethnic differences in HPV vaccination uptake may be partly explained by concerns that were only reported by parents from some ethnic groups. Interventions to improve uptake may need to tackle difficult topics like abstinence from sex before marriage, and use a targeted format

Problems and Aspects of Energy-Driven Wavefunction Collapse Models

Four problematic circumstances are considered, involving models which describe dynamical wavefunction collapse toward energy eigenstates, for which it is shown that wavefunction collapse of macroscopic objects does not work properly. In one case, a common particle position measuring situation, the apparatus evolves to a superposition of macroscopically distinguishable states (does not collapse to one of them as it should) because each such particle/apparatus/environment state has precisely the same energy spectrum. Second, assuming an experiment takes place involving collapse to one of two possible outcomes which is permanently recorded, it is shown in general that this can only happen in the unlikely case that the two apparatus states corresponding to the two outcomes have disjoint energy spectra. Next, the progressive narrowing of the energy spectrum due to the collapse mechanism is considered. This has the effect of broadening the time evolution of objects as the universe evolves. Two examples, one involving a precessing spin, the other involving creation of an excited state followed by its decay, are presented in the form of paradoxes. In both examples, the microscopic behavior predicted by standard quantum theory is significantly altered under energy-driven collapse, but this alteration is not observed by an apparatus when it is included in the quantum description. The resolution involves recognition that the statevector describing the apparatus does not collapse, but evolves to a superposition of macroscopically different states.Comment: 17 page