Key transmission parameters of an institutional outbreak during the 1918 influenza pandemic estimated by mathematical modelling

AIM: To estimate the key transmission parameters associated with an outbreak of pandemic influenza in an institutional setting (New Zealand 1918). METHODS: Historical morbidity and mortality data were obtained from the report of the medical officer for a large military camp. A susceptible-exposed-infectious-recovered epidemiological model was solved numerically to find a range of best-fit estimates for key epidemic parameters and an incidence curve. Mortality data were subsequently modelled by performing a convolution of incidence distribution with a best-fit incidence-mortality lag distribution. RESULTS: Basic reproduction number (R(0)) values for three possible scenarios ranged between 1.3, and 3.1, and corresponding average latent period and infectious period estimates ranged between 0.7 and 1.3 days, and 0.2 and 0.3 days respectively. The mean and median best-estimate incidence-mortality lag periods were 6.9 and 6.6 days respectively. This delay is consistent with secondary bacterial pneumonia being a relatively important cause of death in this predominantly young male population. CONCLUSION: These R(0 )estimates are broadly consistent with others made for the 1918 influenza pandemic and are not particularly large relative to some other infectious diseases. This finding suggests that if a novel influenza strain of similar virulence emerged then it could potentially be controlled through the prompt use of major public health measures

The Effect of Selection for Desiccation Resistance on Cold Tolerance of Drosophila Melanogaster

Low Temperature and Desiccation Stress Are Thought to Be Mechanistically Similar in Insects, and Several Studies Indicate that There is a Degree of Cross-Tolerance between Them, such that Increased Cold Tolerance Results in Greater Desiccation Tolerance and Vice Versa. This Assertion is Tested at an Evolutionary Scale by Examining Basal Cold Tolerance, Rapid Cold-Hardening (RCH) and Chill Coma Recovery in Replicate Populations of Drosophila Melanogaster Selected for Desiccation Resistance (With Controls for Both Selection and Concomitant Starvation) for over 50 Generations. All of the Populations Display a RCH Response, and There is No Effect of Selection Regime on RCH or Basal Cold Tolerance, Although There Are Differences in Basal Cold Tolerance between Sampling Dates, Apparently Related to Inter-Individual Variation in Development Time. Flies Selected for Desiccation Tolerance Recover from Chill Coma Slightly, But Significantly, Faster Than Control and Starvation-Control Flies. These Findings Provide Little Support for Cross-Tolerance between Survival of Near-Lethal Cold and Desiccation Stress in D. Melanogaster. © 2007 the Authors

Meson Condensation in Dense Matter Revisited

The results for meson condensation in the literature vary markedly depending on whether one uses chiral perturbation theory or the current-algebra-plus-PCAC approach. To elucidate the origin of this discrepancy, we re-examine the role of the sigma-term in meson condensation. We find that the resolution of the existing discrepancy requires a knowledge of terms in the Lagrangian that are higher order in density than hitherto considered.Comment: 10pages, USC(NT)-94-

Multiple Monoenergetic Gamma Radiography (MMGR) with a compact superconducting cyclotron

Smuggling of special nuclear materials (SNM) and nuclear devices through borders and ports of entry constitutes a major risk to global security. Technologies are needed to reliably screen the flow of commerce for the presence of high-$Z$ materials such as uranium and plutonium. Here we present an experimental proof-of-concept of a technique which uses inelastic ($p,p'$) nuclear reactions to generate monoenergetic photons, which provide means to measure the areal density and the effective-$Z$ ($Z_{\text{eff}}$) of an object with an accuracy which surpasses that achieved by current methods. We use an ION-12$^{ \text{SC}}$ superconducting 12~MeV proton cyclotron to produce 4.4, 6.1, 6.9, and 7.1~MeV photons from a variety of nuclear reactions. Using these photons in a transmission mode we show that we are able to accurately reconstruct the areal densities and $Z_{\text{eff}}$ of a test object. This methodology could enable mobile applications to screen commercial cargoes with high material specificity, providing a means of distinguishing common cargo materials from high-Z materials that include uranium and plutonium

An alpha theory of time-dependent warped accretion discs

The non-linear fluid dynamics of a warped accretion disc was investigated in an earlier paper by developing a theory of fully non-linear bending waves in a thin, viscous disc. That analysis is here extended to take proper account of thermal and radiative effects by solving an energy equation that includes viscous dissipation and radiative transport. The problem is reduced to simple one-dimensional evolutionary equations for mass and angular momentum, expressed in physical units and suitable for direct application. This result constitutes a logical generalization of the alpha theory of Shakura & Sunyaev to the case of a time-dependent warped accretion disc. The local thermal-viscous stability of such a disc is also investigated.Comment: 16 pages, 3 figures, to be published in MNRA

Patient understanding and acceptability of an early lung cancer diagnosis trial: a qualitative study

Background The ELCID (Early Lung Cancer Investigation and Diagnosis) trial was a feasibility randomised controlled trial examining the effect on lung cancer diagnosis of lowering the threshold for referral for urgent chest x-ray for smokers and recent ex-smokers, aged over 60 years with new chest symptoms. The qualitative component aimed to explore the feasibility of individually randomising patients to an urgent chest x-ray or not and to investigate any barriers to patient recruitment and participation. We integrated this within the feasibility trial to inform the design of any future definitive trial, particularly in view of the lack of research exploring symptomatic patients’ experiences of participating in diagnostic trials for possible/suspected lung cancer. Although previous studies contributed valuable information concerning screening for lung cancer and patient participation in trials, this paper is the first to explore issues relating to this specific patient group. Methods Qualitative interviews were conducted with 21 patients, comprising 9 who had been randomised to receive an immediate chest x-ray, 10 who were randomised to receive the standard treatment according to the National Institute for Health and Care Excellence guidelines, and 2 who chose not to participate in the trial. Interviews were analysed using a framework approach. Results The findings of this analysis showed that altruism, personal benefit and the reassurance of not having lung cancer were important factors in patient participation. However, patients largely believed that being in the intervention arm was more beneficial, highlighting a lack of understanding of clinical equipoise. Disincentives to participation in the trial included the stigmatisation of patients who smoked (given the inclusion criteria). Although the majority of patients reported that they were happy with the trial design, there was evidence of poor understanding. Last, for several patients, placing trust in health professionals was preferred to understanding the trial processes. Conclusions The integration of a qualitative study focusing on participant experience as a secondary outcome of a feasibility trial enabled exploration of patient response to participation and recruitment. The study demonstrated that although it is feasible to recruit patients to the ELCID trial, more work needs to be done to ensure an understanding of study principles and also of smoking stigmatisation

Universality of Frequency and Field Scaling of the Conductivity Measured by Ac-Susceptibility of a Ybco-Film

Utilizing a novel and exact inversion scheme, we determine the complex linear conductivity $\sigma (\omega )$ from the linear magnetic ac-susceptibility which has been measured from 3\,mHz to 50\,MHz in fields between 0.4\,T and 4\,T applied parallel to the c-axis of a 250\,nm thin disk. The frequency derivative of the phase $\sigma ''/\sigma '$ and the dynamical scaling of $\sigma (\omega)$ above and below $T_g(B)$ provide clear evidence for a continuous phase transition at $T_g$ to a generic superconducting state. Based on the vortex-glass scaling model, the resulting critical exponents $\nu$ and $z$ are close to those frequently obtained on films by other means and associated with an 'isotropic' vortex glass. The field effect on $\sigma(\omega)$ can be related to the increase of the glass coherence length, $\xi_g\sim B$.Comment: 8 pages (5 figures upon request), revtex 3.0, APK.94.01.0

Empowerment or Engagement? Digital Health Technologies for Mental Healthcare

We argue that while digital health technologies (e.g. artificial intelligence, smartphones, and virtual reality) present significant opportunities for improving the delivery of healthcare, key concepts that are used to evaluate and understand their impact can obscure significant ethical issues related to patient engagement and experience. Specifically, we focus on the concept of empowerment and ask whether it is adequate for addressing some significant ethical concerns that relate to digital health technologies for mental healthcare. We frame these concerns using five key ethical principles for AI ethics (i.e. autonomy, beneficence, non-maleficence, justice, and explicability), which have their roots in the bioethical literature, in order to critically evaluate the role that digital health technologies will have in the future of digital healthcare