Writing Social Determinants Into and Out of Cancer Control: An Assessment of Policy Practice’

A large literature concurs that social determinants of health are demonstrable, important, and insufficiently attended to in policy and practice. A resulting priority for research should be to determine how the social determinants of health can best be addressed. The authors aim to use this paper to support more effective transfer of social determinants research into policy by: (1) describing a qualitative analysis of thirty-two cancer control policy documents from six OECD countries and two transnational organizations, demonstrating great variability in the treatment of social determinants in these policies (2) critiquing these various policy practices in relation to their likely impact on social determinants of health, and (3) advancing a tool that policy writers can use to assess the way in which social determinants of health have been addressed in their work. In the sample of policy documents, the distinction between structural and intermediate determinants, population-based and targeted interventions, and their respective relationships to equity were not always clear. The authors identified four approaches to social determinants (acknowledging SDH, auditing SDH, stating aims regarding SDH and setting out actions on SDH), and five ways of writing about the relationship between social determinants and cancer risk. These five discourses implied, respectively: that group membership was intrinsically risky; that not enough was known about SDH; that risk arose from choices made by individuals; that groups were constrained by circumstance; or that structural change was necessary. Socio-cultural factors were generally presented negatively: New Zealand policies modeled a possible alternative. Based on their empirical work, the authors propose a matrix and a set of questions to guide the development and assessment of health policy

Balance, balancing and health

In this article we explore the concept of balance in the context of health. We became interested in balance during a grounded theory study of lay conceptualizations of cancer risk, in which participants were concerned with having a good life, which relied heavily on balancing processes. This led us to the qualitative literature about balance in the context of health, which was large and in need of synthesis. We identified 170 relevant studies and used Thomas and Harden’s technique of “thematic synthesis” to identify key balance-related themes and to develop these into more abstract analytic categories. We found that balance and balancing were salient to people in three health-related contexts: health maintenance, disease or disability management and lay or professional caregiving. In each of these contexts, balance or imbalance could be a state or a process. In addition, those using the word had either an internally- or externally focused orientation to the world around them. Clinicians and public health practitioners might benefit from using these insights in their research and communication. Keywords communication, medical; concept analysis; health and well-being; health promotion; qualitative analysisNHMR

Writing the risk of cancer: cancer risk in policy documents.

In this paper we examine how cancer risk is written in cancer policy documents from the English speaking OECD nations. We offer an audit of the multiple ways in which cancer risk is conceptualized and presented in health policy and professional contexts with the long term aim of comparing this with lay conceptualizations. Our study sampled cancer policy documents produced by six nations, the World Health Organisation and the International Union for Cancer Control since 2000 and analysed them iteratively through questions and codes. Whilst the documents contained a comprehensive range of concepts and locations for cancer risk, our analysis found two predominant representations: firstly, well established metaphors that depict cancer as uniformly dreadful and life threatening; and secondly, through a concentration on five behavioural risk factors (tobacco smoking, drinking alcohol, inadequate nutrition, sun exposure and physical inactivity) and one bodily state (overweight). We discuss the implications of this dual focus and of other tensions within ideas about cancer risk that we identified for risk communication

Stability of the modulator in a plasma-modulated plasma accelerator

We explore the regime of operation of the modulator stage of a recently proposed laser-plasma accelerator scheme [Phys. Rev. Lett. 127, 184801 (2021)], dubbed the plasma-modulated plasma accelerator (P-MoPA). The P-MoPA scheme offers a potential route to high-repetition-rate, GeV-scale plasma accelerators driven by picosecond-duration laser pulses from, for example, kilohertz thin-disk lasers. The first stage of the P-MoPA scheme is a plasma modulator in which a long, high-energy “drive” pulse is spectrally modulated by copropagating in a plasma channel with the low-amplitude plasma wave driven by a short, low-energy “seed” pulse. The spectrally modulated drive pulse is converted to a train of short pulses, by introducing dispersion, which can resonantly drive a large wakefield in a subsequent accelerator stage with the same on-axis plasma density as the modulator. In this paper we derive the 3D analytic theory for the evolution of the drive pulse in the plasma modulator and show that the spectral modulation is independent of transverse coordinate, which is ideal for compression into a pulse train. We then identify a transverse mode instability (TMI), similar to the TMI observed in optical fiber lasers, which sets limits on the energy of the drive pulse for a given set of laser-plasma parameters. We compare this analytic theory with particle-in-cell (PIC) simulations and find that even higher energy drive pulses can be modulated than those demonstrated in the original proposal

Quasi-phase-matched high-order harmonic generation using tunable pulse trains

A simple technique for generating trains of ultrafast pulses is demonstrated in which the linear separation between pulses can be varied continuously over a wide range. These pulse trains are used to achieve tunable quasi-phase-matching of high harmonic generation over a range of harmonic orders up to the harmonic cut-off, resulting in enhancements of the harmonic intensity in excess of an order of magnitude. The peak enhancement depends on the separation between pulses, as well as the number of pulses in the train, representing an easily tunable source of quasi-phase-matched high harmonic generation

Optimised XUV holography using spatially shaped high harmonic beams

A phase-only spatial light modulator is used to generate multiple infrared foci, the positions and intensities of which can be controlled programmably, allowing the generation and control of multiple high harmonic beams. Using two such high harmonic beams Fourier transform holography is performed with separate illumination of the object and reference pinhole, making optimal use of the available photon flux. This technique provides new opportunities for imaging at extreme ultraviolet wavelengths

All-optical GeV electron bunch generation in a laser-plasma accelerator via truncated-channel injection.

We describe a simple scheme, truncated-channel injection, to inject electrons directly into the wakefield driven by a high-intensity laser pulse guided in an all-optical plasma channel. We use this approach to generate dark-current-free 1.2 GeV, 4.5% relative energy spread electron bunches with 120 TW laser pulses guided in a 110 mm-long hydrodynamic optical-field-ionized plasma channel. Our experiments and particle-in-cell simulations show that high-quality electron bunches were only obtained when the drive pulse was closely aligned with the channel axis, and was focused close to the density down ramp formed at the channel entrance. Start-to-end simulations of the channel formation, and electron injection and acceleration show that increasing the channel length to 410 mm would yield 3.65 GeV bunches, with a slice energy spread ∼5×10^{-4}

Demonstration of tunability of HOFI waveguides via start-to-end simulations

In recent years, hydrodynamic optical-field-ionized (HOFI) channels have emerged as a promising technique to create laser waveguides suitable for guiding tightly focused laser pulses in a plasma, as needed for laser-plasma accelerators. While experimental advances in HOFI channels continue to be made, the underlying mechanisms and the roles of the main parameters remain largely unexplored. In this paper, we propose a start-to-end simulation pipeline of the HOFI channel formation and the resulting laser guiding and use it to explore the underlying physics and the tunability of HOFI channels. This approach is benchmarked against experimental measurements. HOFI channels are shown to feature excellent guiding properties over a wide range of parameters, making them a promising and tunable waveguide option for laser-plasma accelerators

Spatially resolved common-path high-order harmonic interferometry

In this letter we report on interference between high harmonic emission from two longitudinally separated sources driven by the same laser pulse. Compared with previous implementations of in-line interferometry we demonstrate that by analysing the spatially-resolved harmonic signal as a function of longitudinal separation quantum trajectory-dependent interference can be identified. The inline geometry demonstrated here offers a high degree of stability, since both harmonic sources are generated from the same driving pulse, as opposed to pulse replicas, which has typically been the case in other interferometric schemes. The inherent synchronization and high timing stability afforded by this approach offers a new route for the measurement and timing of ultrafast processes

Séparations mécaniques fluide/solide

Licencedécantation gravitaire ; centrifugations (décantation centrifuge et cyclones) ; filtrations (sur support et en profondeur