Scanning Tunneling Spectroscopy on the novel superconductor CaC6

We present scanning tunneling microscopy and spectroscopy of the newly discovered superconductor CaC$_6$. The tunneling conductance spectra, measured between 3 K and 15 K, show a clear superconducting gap in the quasiparticle density of states. The gap function extracted from the spectra is in good agreement with the conventional BCS theory with $\Delta(0)$ = 1.6 $\pm$ 0.2 meV. The possibility of gap anisotropy and two-gap superconductivity is also discussed. In a magnetic field, direct imaging of the vortices allows to deduce a coherence length in the ab plane $\xi_{ab}\simeq$ 33 nm

Degree spectra for transcendence in fields

We show that for both the unary relation of transcendence and the finitary relation of algebraic independence on a field, the degree spectra of these relations may consist of any single computably enumerable Turing degree, or of those c.e. degrees above an arbitrary fixed $\Delta^0_2$ degree. In other cases, these spectra may be characterized by the ability to enumerate an arbitrary $\Sigma^0_2$ set. This is the first proof that a computable field can fail to have a computable copy with a computable transcendence basis

The impact of injecting networks on hepatitis C transmission and treatment in people who inject drugs

With the development of new highly efficacious direct acting antiviral treatments (DAAs) for hepatitis C (HCV), the concept of treatment as prevention is gaining credence. To date the majority of mathematical models assume perfect mixing with injectors having equal contact with all other injectors. This paper explores how using a networks based approach to treat people who inject drugs (PWID) with DAAs affects HCV prevalence. Method: Using observational data we parameterized an Exponential Random Graph Model containing 524 nodes. We simulated transmission of HCV through this network using a discrete time, stochastic transmission model. The effect of five treatment strategies on the prevalence of HCV was investigated; two of these strategies were 1) treat randomly selected nodes and 2) “treat your friends” where an individual is chosen at random for treatment and all their infected neighbours are treated. Results: As treatment coverage increases, HCV prevalence at 10 years reduces for both the high efficacy and low efficacy treatment. Within each set of parameters, the “treat your friends” strategy performed better than the random strategy being most marked for higher efficacy treatment. For example over 10 years of treating 25 per 1000 PWID, the prevalence drops from 50% to 40% for the random strategy, and to 33% for the “treat your friends” strategy (6.5% difference, 95% CI 5.1 – 8.1%). Discussion: “Treat your friends” is a feasible means of utilising network strategies to improve treatment efficiency. In an era of highly efficacious and highly tolerable treatment such an approach will benefit not just the individual but the community more broadly by reducing the prevalence of HCV amongst PWID

Analysis of Integrating Sphere Performance for IR Enhanced DT Layering

Absorbed IR energy can supplement the beta decay energy from DT ice to improve the driving force toward uniform layers. A significant problem with this approach has been to deliver the added IR energy with sufficient uniformity to enhance rather than destroy the uniformity of the ice layers. Computer modeling has indicated that one can achieve {approximately}1% uniformity in the angular variation of the absorbed power using an integrating sphere containing holes large enough to allow external inspection of the ice layer uniformity. The power required depends on the integrating sphere size, a 25 mm diameter sphere requires {approximately}35 mW of IR to deposit as much energy in the ice as the 50 mW/cm{sup 3}(35 pW total) received from tritium decay in DT. Power absorbed in the plastic can cause unacceptable ice-layer non-uniformities for the integrating sphere design considered here

Weighted Sobolev spaces of radially symmetric functions

We prove dilation invariant inequalities involving radial functions, poliharmonic operators and weights that are powers of the distance from the origin. Then we discuss the existence of extremals and in some cases we compute the best constants.Comment: 38 page

The influence of corporate market power on health: exploring the structure-conduct-performance model from a public health perspective

Background The detrimental impact of dominant corporations active in health-harming commodity industries is well recognised. However, to date, existing analyses of the ways in which corporations influence health have paid limited attention to corporate market power. Accordingly, the public health implications of concentrated market structures, the use of anti-competitive market strategies, and the ways in which market power mediates the allocation and distribution of resources via market systems, remain relatively unexplored. To address this gap, this paper aimed to identify and explore key literature that could inform a comprehensive framework to examine corporate market power from a public health perspective. The ultra-processed food (UPF) industry was used to provide illustrative examples. Methods A scoping review of a diverse range of literature, including Industrial Organization, welfare economics, global political economy and antitrust policy, was conducted to identify important concepts and metrics that could be drawn upon within the field of public health to understand and explore market power. The Structure-Conduct-Performance (SCP) model, a guiding principle of antitrust policy and the regulation of market power, was used as an organising framework. Results We described each of the components of the traditional SCP model and how they have historically been used to assess market power through examining the interrelations between the structure of industries and markets, the conduct of dominant firms, and the overall ability of markets and firms to efficiently allocate and distribute the scarce resources. Conclusion We argue that the SCP model is well-placed to broaden public health research into the ways in which corporations influence health. In addition, the development of a comprehensive framework based on the key findings of this paper could help the public health community to better engage with a set of policy and regulatory tools that have the potential to curb the concentration of corporate power for the betterment of population health

Maximising the wealth of few at the expense of the health of many: a public health analysis of market power and corporate wealth and income distribution in the global soft drink market

Background Many of the harms created by the global soft drink industry that directly influence human and planetary health are well documented. However, some of the ways in which the industry indirectly affects population health, via various socio-economic pathways, have received less attention. This paper aimed to analyse the extent to which market power and corporate wealth and income distribution in the global soft drink market negatively impact public health and health equity. In doing so, the paper sought to contribute to the development of a broad-based public health approach to market analysis. A range of dimensions (e.g., market concentration; financial performance; corporate wealth and income distribution) and indicators (e.g., Herfindahl Hirschman Index; earnings relative to the industry average; effective tax rates; and shareholder value ratios) were descriptively analysed. Empirical focus was placed on the two dominant global soft drink manufacturers. Results Coca-Cola Co, and, to a lesser extent, PepsiCo, operate across an extensive patchwork of highly concentrated markets. Both corporations control vast amounts of wealth and resources, and are able to allocate relatively large amounts of money to potentially harmful practices, such as extensive marketing of unhealthy products. Over recent decades, the proportion of wealth and income transferred by these firms to their shareholders has increased substantially; whereas the proportion of wealth and income redistributed by these two firms to the public via income taxes has considerably decreased. Meanwhile, the distribution of soft drink consumption is becoming increasingly skewed towards population groups in low and middle-income countries (LMICs). Conclusions Market power and corporate wealth and income distribution in the global soft drink market likely compound the market’s maldistribution of harms, and indirectly influence health by contributing to social and economic inequalities. Indeed, a ‘double burden of maldistribution’ pattern can be seen, wherein the wealth of the shareholders of the market’s dominant corporations, a group over-represented by a small and wealthy elite, is maximised largely at the expense of the welfare of LMICs and lower socioeconomic groups in high-income countries. If this pattern continues, the appropriate role of the global soft drink market as part of sustainable economic development will require rethinking

Hepatitis C transmission and treatment as prevention - The role of the injecting network

Background: The hepatitis C virus (HCV) epidemic is a major health issue; in most developed countries it is driven by people who inject drugs (PWID). Injecting networks powerfully influence HCV transmission. In this paper we provide an overview of 10 years of research into injecting networks and HCV, culminating in a network-based approach to provision of direct-acting antiviral therapy. Methods: Between 2005 and 2010 we followed a cohort of 413 PWID, measuring HCV incidence, prevalence and injecting risk, including network-related factors. We developed an individual-based HCV transmission model, using it to simulate the spread of HCV through the empirical social network of PWID. In addition, we created an empirically grounded network model of injecting relationships using exponential random graph models (ERGMs), allowing simulation of realistic networks for investigating HCV treatment and intervention strategies. Our empirical work and modelling underpins the TAP Study, which is examining the feasibility of community-based treatment of PWID with DAAs. Results: We observed incidence rates of HCV primary infection and reinfection of 12.8 per 100 person-years (PY) (95%CI: 7.7-20.0) and 28.8 per 100 PY (95%CI: 15.0-55.4), respectively, and determined that HCV transmission clusters correlated with reported injecting relationships. Transmission modelling showed that the empirical network provided some protective effect, slowing HCV transmission compared to a fully connected, homogenous PWID population. Our ERGMs revealed that treating PWID and all their contacts was the most effective strategy and targeting treatment to infected PWID with the most contacts the least effective. Conclusion: Networks-based approaches greatly increase understanding of HCV transmission and will inform the implementation of treatment as prevention using DAAs