An early medieval lead-smelting bole from Banc Tynddol, Cwmystwyth, Ceredigion

Excavations in 2002 at Cwmystwyth, in Central Wales, found an ancient lead smelting site. There are remains of the medieval and the Roman periods. This paper describes in brief the excavation of the medieval lead bole (Timberlake 2002a) but also provides an archaeological reconstruction of this and details of an experimental lead smelt carried out at the site in 2003 (by ST). The analytical study (by LA) is of the medieval metallurgical debris excavated in 2002, mostly slag, but also ore and lead. The aim was to understand the raw material, the metal produced and the smelting process. The ore smelted was predominantly galena but with no detectable silver, showing it was probably exploited to produce lead. The extremely high sulphur content of the slag indicates that the ore was not roasted before smelting. It is argued that the medieval activity was small-scale, smelting a very rich ore. The furnaces apparently did not require much capital investment, enabling a short-lived and/or exploratory smelting operation

Is the E-Liquid Industry Regulating Itself? A Look at E-Liquid Internet Vendors in the United States

INTRODUCTION: The objective of this study was to assess whether the nascent, but rapidly growing e-liquid industry prohibits Internet sales to minors and employs safety measures to prevent accidental poisonings. METHODS: A stratified simple random sample (n = 120) was selected from the target population (N = 1107) of US online vendors of e-liquid in July 2015. The vendors were stratified and subsequently oversampled by trade association membership and vendor popularity. Three minors aged 16 to 17, who were supervised by adult research staff, attempted to purchase e-liquid from the 120 online vendors using debit cards issued in their names. Measures included vendors' use of age verification, warning labels on e-liquid bottles, and child-resistant packaging. RESULTS: Statistically significant differences were observed by vendor popularity, but not by membership in a trade association. The differences by vendor popularity, however, occurred for measures that were limited to an age warning and list of ingredients. The most striking finding was the scant vendors (n = 4) who successfully prevented the sale of e-liquid to the minors. In contrast, 87.5% and 53.9% of the bottles contained child-resistant packaging and a health warning label, respectively. CONCLUSIONS: Irrespective of trade association membership or vendor popularity, online vendors of e-liquids are not taking the proper precautions in preventing sales to minors. The FDA's upcoming deeming rules on e-cigarette products should include explicit requirements for offline and online e-liquid vendors, particularly the use of effective age verification, warning labels, and child-resistant packaging. IMPLICATIONS: This study demonstrates that, in the absence of any current FDA regulation of e-liquid products, self-regulation among vendors is not effective in preventing product acquisition by minors. Lax oversight of the e-liquid industry may draw consumers to bypass current tobacco control restrictions implemented in face-to-face sales settings. As a consequence, there may be an increase in online sales to minors. Further regulation of the industry may increase the already prevalent use of child-resistant packaging, leading to fewer cases of accidental nicotine poisoning

Interaction and Localization of One-electron Orbitals in an Organic Molecule: Fictitious Parameter Analysis for Multi-physics Simulations

We present a new methodology to analyze complicated multi-physics simulations by introducing a fictitious parameter. Using the method, we study quantum mechanical aspects of an organic molecule in water. The simulation is variationally constructed from the ab initio molecular orbital method and the classical statistical mechanics with the fictitious parameter representing the coupling strength between solute and solvent. We obtain a number of one-electron orbital energies of the solute molecule derived from the Hartree-Fock approximation, and eigenvalue-statistical analysis developed in the study of nonintegrable systems is applied to them. Based on the results, we analyze localization properties of the electronic wavefunctions under the influence of the solvent.Comment: 4 pages, 5 figures, the revised version will appear in J. Phys. Soc. Jpn. Vol.76 (No.1

Computation in Classical Mechanics

There is a growing consensus that physics majors need to learn computational skills, but many departments are still devoid of computation in their physics curriculum. Some departments may lack the resources or commitment to create a dedicated course or program in computational physics. One way around this difficulty is to include computation in a standard upper-level physics course. An intermediate classical mechanics course is particularly well suited for including computation. We discuss the ways we have used computation in our classical mechanics courses, focusing on how computational work can improve students' understanding of physics as well as their computational skills. We present examples of computational problems that serve these two purposes. In addition, we provide information about resources for instructors who would like to include computation in their courses.Comment: 6 pages, 3 figures, submitted to American Journal of Physic

Exploring connections between pollinator health and human health

Despite recent advances in understanding the role of biodiversity in ecosystem-service provision, the links between the health of ecosystem-service providers and human health remain more uncertain. During the past decade, an increasing number of studies have argued for the positive impacts of healthy pollinator communities (defined as functionally and genetically diverse species assemblages that are sustained over time) on human health. Here, we begin with a systematic review of these impacts, finding only two studies that concomitantly quantified aspects of pollinator health and human health. Next, we identify relevant research relating to four pathways linking pollinator health and human health: Nutrition, medicine provisioning, mental health and environmental quality. These benefits are obtained through improved pollination of nutritious crops and an estimated approximately 28 000 animal-pollinated medicinal plants; the provisioning of pollinator-derived products such as honey; the maintenance of green spaces and biocultural landscapes that improve mental health; and cleaner air, water and food resulting from pollinator-centred initiatives to reduce agrochemical use. We suggest that pollinator diversity could be a proxy for the benefits that landscapes provide to human health. This article is part of the theme issue 'Natural processes influencing pollinator health: From chemistry to landscapes'.Fil: Garibaldi, Lucas Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural. - Universidad Nacional de Rio Negro. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; ArgentinaFil: Gómez Carella, Dulce Sol. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural. - Universidad Nacional de Rio Negro. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; ArgentinaFil: Nabaes Jodar, Diego Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural. - Universidad Nacional de Rio Negro. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; ArgentinaFil: Smith, Matthew R.. Harvard University. Harvard School of Public Health; Estados UnidosFil: Timberlake, Thomas P.. University of Bristol; Reino UnidoFil: Myers, Samuel S.. Harvard University. Harvard School of Public Health; Estados Unidos. Harvard University; Estados Unido

Scattering properties of a cut-circle billiard waveguide with two conical leads

We examine a two-dimensional electron waveguide with a cut-circle cavity and conical leads. By considering Wigner delay times and the Landauer-B\"{u}ttiker conductance for this system, we probe the effects of the closed billiard energy spectrum on scattering properties in the limit of weakly coupled leads. We investigate how lead placement and cavity shape affect these conductance and time delay spectra of the waveguide.Comment: 18 pages, 11 figures, accepted for publication in Phys. Rev. E (Jan. 2001

Classical Scattering for a driven inverted Gaussian potential in terms of the chaotic invariant set

We study the classical electron scattering from a driven inverted Gaussian potential, an open system, in terms of its chaotic invariant set. This chaotic invariant set is described by a ternary horseshoe construction on an appropriate Poincare surface of section. We find the development parameters that describe the hyperbolic component of the chaotic invariant set. In addition, we show that the hierarchical structure of the fractal set of singularities of the scattering functions is the same as the structure of the chaotic invariant set. Finally, we construct a symbolic encoding of the hierarchical structure of the set of singularities of the scattering functions and use concepts from the thermodynamical formalism to obtain one of the measures of chaos of the fractal set of singularities, the topological entropy.Comment: accepted in Phy. Rev.

Identifying evidence for past mining and metallurgy from a record of metal contamination preserved in an ombrotrophic mire near Leadhills, SW Scotland, UK

This study presents a new 3600-year record of past metal contamination from a bog located close to the Leadhills and Wanlockhead orefield of southwest Scotland. A peat core, collected from Toddle Moss, was radiocarbon (14C) dated and analysed for trace metal concentrations (by EMMA) and lead isotopes (by ICP-MS) to reconstruct the atmospheric deposition history of trace metal contamination, in particular, lead. The results show good agreement with documented historical and archaeological records of mining and metallurgy in the region: the peak in metal mining during the 18th century, the decline of lead mining during the Anglo-Scottish war and lead smelting during the early medieval period. There may also have been earlier workings during the Late Bronze and Iron Ages indicated by slight increases in lead concentrations, the Pb/Ti ratio and a shift in 206Pb/207Pb ratios, which compare favourably to the signatures of a galena ore from Leadhills and Wanlockhead. In contrast to other records across Europe, no sizeable lead enrichment was recorded during the Roman Iron Age, suggesting that the orefield was not a significant part of the Roman lead extraction industry in Britain. These findings add to the various strands of archaeological evidence that hint at an early lead extraction and metallurgical industry based in southern Scotland. The results also provide further evidence for specific regional variations in the evolution of mining and metallurgy and an associated contamination signal during prehistoric and Roman times across Europe