The analytic structure of amplitudes on backgrounds from gauge invariance and the infra-red

Gauge invariance and soft limits can be enough to determine the analytic structure of scattering amplitudes in certain theories. This prompts the question of how gauge invariance is connected to analytic structure in more general theories. Here we focus on QED in background plane waves. We show that imposing gauge invariance introduces new virtuality poles into internal momenta on which amplitudes factorise into a series of terms. Each term is gauge invariant, has a different analytic structure in external momenta, and exhibits a hard/soft factorisation. The introduced poles are dictated by infra-red behaviour, which allows us to extend our results to scalar Yukawa theory. The background is treated non-perturbatively throughout.Comment: 25 pages, 4 figures. V2: added references. V3: Updated to match published version appearing in JHEP [JHEP 04 (2020) 078

Poor Individual Risk Classification From Adverse Childhood Experiences Screening

Introduction: Adverse childhood experiences confer an increased risk for physical and mental health problems across the population, prompting calls for routine clinical screening based on reported adverse childhood experience exposure. However, recent longitudinal research has questioned whether adverse childhood experiences can accurately identify ill health at an individual level. // Methods: Revisiting data collected for the Adverse Childhood Experience Study between 1995 and 1997, this study derived approximate area under the curve estimates to test the ability of the retrospectively reported adverse childhood experience score to discriminate between adults with and without a range of common health risk factors and disease conditions. Furthermore, the classification accuracy of a recommended clinical definition for high-risk exposure (≥4 versus 0–3 adverse childhood experiences) was evaluated on the basis of sensitivity, specificity, positive and negative predictive values, and positive likelihood ratios. // Results: Across all health outcomes, the levels of discrimination for the continuous adverse childhood experience score ranged from very poor to fair (area under the curve=0.50–0.76). The binary classification of ≥4 versus 0–3 adverse childhood experiences yielded high specificity (true-negative detection) and negative predictive values (absence of ill health among low-risk adverse childhood experience groups). However, sensitivity (true-positive detection) and positive predictive values (presence of ill health among high-risk adverse childhood experience groups) were low, whereas positive likelihood ratios suggested only minimal-to-moderate increases in health risks among individuals reporting ≥4 adverse childhood experiences versus that among those reporting 0–3. // Conclusions: These findings suggest that screening based on the adverse childhood experience score does not accurately identify those individuals at high risk of health problems. This can lead to both allocation of unnecessary interventions and lack of provision of necessary support

Locally monochromatic approximation to QED in intense laser fields

We derive an approximation to QED effects in strong background fields which can be employed to improve numerical simulations of laser-particle collisions. Treating the laser as a plane wave of arbitrary intensity, we split the wave into fast (carrier) and slow (envelope) modes. We solve the interaction dynamics exactly for the former while performing a local expansion in the latter. This yields a `locally monochromatic' approximation (LMA), which we compare with exact spectra for nonlinear Compton scattering and nonlinear Breit-Wheeler pair production, for realistic laser pulse durations. We show that, as an improvement over the commonly used `locally-constant field' approximation, the LMA exactly reproduces the correct low energy behaviour of particle spectra, as well as the position and amplitude of harmonic features.Comment: 19 pages, 7 figure

From local to nonlocal: higher fidelity simulations of photon emission in intense laser pulses

State-of-the-art numerical simulations of quantum electrodynamical (QED) processes in strong laser fields rely on a semiclassical combination of classical equations of motion and QED rates, which are calculated in the locally constant field approximation. However, the latter approximation is unreliable if the amplitude of the fields, $a_0$, is comparable to unity. Furthermore, it cannot, by definition, capture interference effects that give rise to harmonic structure. Here we present an alternative numerical approach, which resolves these two issues by combining cycle-averaged equations of motion and QED rates calculated in the locally monochromatic approximation. We demonstrate that it significantly improves the accuracy of simulations of photon emission across the full range of photon energies and laser intensities, in plane-wave, chirped and focused background fields.Comment: 35 pages, 8 figure

Giving stakeholders a voice in governance: Biodiversity priorities for New Zealand's agriculture

Abstract: Mainstreaming biodiversity across government and society is recognised by international policy as critical to achieving positive conservation outcomes. With ‘participatory governance’ increasingly being applied to achieve collective action in conservation, there are growing calls to critically review such processes to capture their complexity and manage for emergent outcomes. This paper critically reviews a case study, aiming to give a broad range of stakeholders a voice in setting biodiversity priorities for New Zealand's agricultural landscape, in relation to four principles for knowledge co‐production in sustainability: context‐based, pluralistic, goal‐orientated and interactive. Aiming to facilitate an inclusive but rapid participation process, while not overburdening those willing to participate, three pathways for engagement were offered. Stakeholder participants were recruited from public, private and civic sectors involved in managing New Zealand's farmland biodiversity. An initial scoping exercise helped elevate biodiversity groups and management actions distinct to New Zealand's social and environmental context. Online surveys then gave stakeholders, from a diverse range of roles and sectors, a nationwide voice to express their own biodiversity interests and needs; these were reviewed by an advisor panel to reach consensus on final priorities that reflected the biodiversity outcomes that matter most to stakeholders involved in managing New Zealand's agricultural landscape and the management practices they considered most relevant to achieving those outcomes. This knowledge co‐production process delivered multiple gains that would not have been achieved had a more traditional science‐based process been applied, such as wide stakeholder engagement, identification of a tangible starting point, mitigation of bias or conflict risks, enhanced researcher and practitioner capabilities and a shared understanding of the opportunities and challenges for future development. Institutes addressing conservation challenges within local contexts need to: be ‘boundary‐spanning’ to manage cross‐scale influences and enable desired conservation behaviours; plan explicitly for the substantial effort required to overcome existing power hierarchies and facilitate transparent and structured decision processes that deliver social justice; better capture the relational values of nature to more successfully leverage peoples’ connection to nature in conservation policies and practices; and incorporate wider environmental (e.g. biosecurity), social, economic and political considerations. A free Plain Language Summary can be found within the Supporting Information of this article

Flecainide reduces Ca2+ spark and wave frequency via inhibition of the sarcolemmal sodium current

AIMS: Ca(2+) waves are thought to be important in the aetiology of ventricular tachyarrhythmias. There have been conflicting results regarding whether flecainide reduces Ca(2+) waves in isolated cardiomyocytes. We sought to confirm whether flecainide inhibits waves in the intact cardiomyocyte and to elucidate the mechanism. METHODS AND RESULTS: We imaged spontaneous sarcoplasmic reticulum (SR) Ca(2+) release events in healthy adult rat cardiomyocytes. Variation in stimulation frequency was used to produce Ca(2+) sparks or waves. Spark frequency, wave frequency, and wave velocity were reduced by flecainide in the absence of a reduction of SR Ca(2+) content. Inhibition of I(Na) via alternative pharmacological agents (tetrodotoxin, propafenone, or lidocaine) produced similar changes. To assess the contribution of I(Na) to spark and wave production, voltage clamping was used to activate contraction from holding potentials of −80 or −40 mV. This confirmed that reducing Na(+) influx during myocyte stimulation is sufficient to reduce waves and that flecainide only causes Ca(2+) wave reduction when I(Na) is active. It was found that Na(+)/Ca(2+)-exchanger (NCX)-mediated Ca(2+) efflux was significantly enhanced by flecainide and that the effects of flecainide on wave frequency could be reversed by reducing [Na(+)](o), suggesting an important downstream role for NCX function. CONCLUSION: Flecainide reduces spark and wave frequency in the intact rat cardiomyocyte at therapeutically relevant concentrations but the mechanism involves I(Na) reduction rather than direct ryanodine receptor (RyR2) inhibition. Reduced I(Na) results in increased Ca(2+) efflux via NCX across the sarcolemma, reducing Ca(2+) concentration in the vicinity of the RyR2

Improving research quality: the view from the UK Reproducibility Network institutional leads for research improvement

The adoption and incentivisation of open and transparent research practices is critical in addressing issues around research reproducibility and research integrity. These practices will require training and funding. Individuals need to be incentivised to adopt open and transparent research practices (e.g., added as desirable criteria in hiring, probation, and promotion decisions, recognition that funded research should be conducted openly and transparently, the importance of publishers mandating the publication of research workflows and appropriately curated data associated with each research output). Similarly, institutions need to be incentivised to encourage the adoption of open and transparent practices by researchers. Research quality should be prioritised over research quantity. As research transparency will look different for different disciplines, there can be no one-size-fits-all approach. An outward looking and joined up UK research strategy is needed that places openness and transparency at the heart of research activity. This should involve key stakeholders (institutions, research organisations, funders, publishers, and Government) and crucially should be focused on action. Failure to do this will have negative consequences not just for UK research, but also for our ability to innovate and subsequently commercialise UK-led discovery

Public awareness of cancer in Britain: a population-based survey of adults

*_Objective:_* To assess public awareness of cancer warning signs, anticipated delay, and perceived barriers to seeking medical advice in the British population. 
Methods: We carried out a population-based survey using face-to-face, computer-assisted interviews to administer the Cancer Awareness Measure (CAM), a newly-developed, validated measure of cancer awareness. The sample included 2216 adults (970 male and 1246 female) recruited as part of the Office for National Statistics Opinions Survey using stratified probability sampling.

*_Results:_* Awareness of cancer warning signs was low when open-ended (recall) questions were used and higher with closed (recognition) questions; but on either measure, awareness was lower in those who were male, younger, and from lower socioeconomic status (SES) groups or ethnic minorities. The most commonly endorsed barriers to help-seeking were difficulty making an appointment, worry about wasting the doctor’s time and worry about what would be found. Emotional barriers were more prominent in lower SES groups and practical barriers (e.g. too busy) more prominent in higher SES groups. Anticipated delay was lower in ethnic minority and lower SES groups. In multivariate analysis, higher symptom awareness was associated with lower anticipated delay, and more barriers with greater anticipated delay.

*_Conclusions:_* A combination of public education about symptoms and empowerment to seek medical advice, as well as support at primary care level, could enhance early presentation and improve cancer outcomes