388 research outputs found
ACHILLES Reading Guide 5: Design considerations for clay earthworks
Steeper slope angles mean less land take, reduced earthworks volumes, reduced embodied carbon, and cost savings. However, they may also come with increased future maintenance. Considering long-term slope conditions in design enables decisions about whole-life cost and carbon trade-offs between initial slope angles, asset-life, and future maintenance
Syndromic surveillance to assess the potential public health impact of the Icelandic volcanic ash plume across the United Kingdom, April 2010
The Eyjafjallajökull volcano in Iceland erupted on 14 April 2010 emitting a volcanic ash plume that spread across the United Kingdom and mainland Europe. The Health Protection Agency and Health Protection Scotland used existing syndromic surveillance systems to monitor community health during the incident: there were no particularly unusual increases in any of the monitored conditions. This incident has again demonstrated the use of syndromic surveillance systems for monitoring community health in real time
Understanding capacity fade in silicon based electrodes for lithium-ion batteries using three electrode cells and upper cut-off voltage studies
Commercial Li-ion batteries are typically cycled between 3.0 and 4.2 V. These voltages limits are chosen based on the characteristics of the cathode (e.g. lithium cobalt oxide) and anode (e.g. graphite). When alternative anode/cathode chemistries are studied the same cut-off voltages are often, mistakenly, used. Silicon (Si) based anodes are widely studied as a high capacity alternative to graphite for Lithium-ion batteries. When silicon-based anodes are paired with high capacity cathodes (e.g. Lithium Nickel Cobalt Aluminium Oxide; NCA) the cell typically suffers from rapid capacity fade. The purpose of this communication is to understand how the choice of upper cut-off voltage affects cell performance in Si/ NCA cells. A careful study of three-electrode cell data will show that capacity fade in Si/NCA cells is due to an ever-evolving silicon voltage profile that pushes the upper voltage at the cathode to >4.4 V (vs. Li/Liþ). This behaviour initially improves cycle efficiency, due to liberation of new lithium, but ultimately reduces cycling efficiency, resulting in rapid capacity fade
Evidence of predation on aquatic vertebrates by serval in the Okavango Delta, Botswana
The serval (Leptailurus serval, Schreber 1776) occurs widely in sub‐Saharan Africa, though is absent from Congo Basin equatorial forest and from highly arid regions of North and South West of the continent. Preferred habitats include grassland and savannah woodland mosaics, frequently associated with rivers, wetlands and flood‐plains. The serval is a specialist rodentivore with rodents, particularly Murids, usually making up between 80% and 90% of their diet across much the species range. They also feed on shrews (Crocidura and Myosorex spp), small birds, amphibians, insects and small reptiles. There are occasional records of servals hunting young of small antelope, ground (Xerus spp) and tree squirrels (Paraxerus spp), larger ground and wading birds (e.g. flamingo, Phoeniconaias spp), hares (Lepus spp), springhares (Pedetes capensis), cane rats (Thryonomys spp), aquatic vertebrates and invertebrates and small carnivores. Grass culms, leaves and fruit are sometimes consumed. Here we present evidence of predation on larger aquatic vertebrates by serval in the Okavango Delta, Botswana.Robertson Foundationhttps://wileyonlinelibrary.com/journal/aje2021-12-31hj2021Mammal Research InstituteZoology and Entomolog
Simulations of the inelastic response of silicon to shock compression
Recent experiments employing nanosecond white-light X-ray diffraction have demonstrated a complex response of pure, single crystal silicon to shock compression on ultra-fast timescales. We present here details of a Lagrangian code which tracks both longitudinal and transverse strains, and successfully reproduces the experimental response by incorporating a model of the shock-induced, yet kinetically inhibited, phase transition. This model is also shown to reproduce results of classical molecular dynamics simulations of shock compressed silicon
Symmetry, Reference Frames, and Relational Quantities in Quantum Mechanics
We propose that observables in quantum theory are properly understood as representatives of symmetry-invariant quantities relating one system to another, the latter to be called a reference system. We provide a rigorous mathematical language to introduce and study quantum reference systems, showing that the orthodox "absolute" quantities are good representatives of observable relative quantities if the reference state is suitably localised. We use this relational formalism to critique the literature on the relationship between reference frames and superselection rules, settling a long-standing debate on the subject
Developing influenza and respiratory syncytial virus activity thresholds for syndromic surveillance in England.
Influenza and respiratory syncytial virus (RSV) are common causes of respiratory tract infections and place a burden on health services each winter. Systems to describe the timing and intensity of such activity will improve the public health response and deployment of interventions to these pressures. Here we develop early warning and activity intensity thresholds for monitoring influenza and RSV using two novel data sources: general practitioner out-of-hours consultations (GP OOH) and telehealth calls (NHS 111). Moving Epidemic Method (MEM) thresholds were developed for winter 2017-2018. The NHS 111 cold/flu threshold was breached several weeks in advance of other systems. The NHS 111 RSV epidemic threshold was breached in week 41, in advance of RSV laboratory reporting. Combining the use of MEM thresholds with daily monitoring of NHS 111 and GP OOH syndromic surveillance systems provides the potential to alert to threshold breaches in real-time. An advantage of using thresholds across different health systems is the ability to capture a range of healthcare-seeking behaviour, which may reflect differences in disease severity. This study also provides a quantifiable measure of seasonal RSV activity, which contributes to our understanding of RSV activity in advance of the potential introduction of new RSV vaccines
Inelastic response of silicon to shock compression
The elastic and inelastic response of [001] oriented silicon to laser compression has been a topic of considerable discussion for well over a decade, yet there has been little progress in understanding the basic behaviour of this apparently simple material. We present experimental x-ray diffraction data showing complex elastic strain profiles in laser compressed samples on nanosecond timescales. We also present molecular dynamics and elasticity code modelling which suggests that a pressure induced phase transition is the cause of the previously reported 'anomalous' elastic waves. Moreover, this interpretation allows for measurement of the kinetic timescales for transition. This model is also discussed in the wider context of reported deformation of silicon to rapid compression in the literature
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