The Impact of Cell Phones and BAC Laws on Motor Vehicle Fatality Rates

This paper develops a set of models for the determinants of automobile fatalities with particular attention devoted to the effects of increased cell phone usage. Cell phones have been associated with both life-taking and life-saving properties. However, prior statistical evaluations of the effects of cell phones have led to fragile results. We develop in this paper econometric models using time series data, allowing for polynomial structures of the regressors. The models are evaluated with a set of specification error tests providing reliable estimates of the effects of the various policy and driving related variables evaluated. The statistical results indicate the effect of cell phones is non-monotonic depending on the volume of phones in use, first having a net life-taking effect, then a net life-saving effect, followed finally with a net life-taking effect as the volume of phone use increases.Motor Vehicle Fatalities, Cell Phones, BAC Laws

Preconditioning and triggering of offshore slope failures and turbidity currents revealed by most detailed monitoring yet at a fjord-head delta

Rivers and turbidity currents are the two most important sediment transport processes by volume on Earth. Various hypotheses have been proposed for triggering of turbidity currents offshore from river mouths, including direct plunging of river discharge, delta mouth bar flushing or slope failure caused by low tides and gas expansion, earthquakes and rapid sedimentation. During 2011, 106 turbidity currents were monitored at Squamish Delta, British Columbia. This enables statistical analysis of timing, frequency and triggers. The largest peaks in river discharge did not create hyperpycnal flows. Instead, delayed delta-lip failures occurred 8–11 h after flood peaks, due to cumulative delta top sedimentation and tidally-induced pore pressure changes. Elevated river discharge is thus a significant control on the timing and rate of turbidity currents but not directly due to plunging river water. Elevated river discharge and focusing of river discharge at low tides cause increased sediment transport across the delta-lip, which is the most significant of all controls on flow timing in this setting

Magnetic-Moment Fragmentation and Monopole Crystallization

The Coulomb phase, with its dipolar correlations and pinch-point-scattering patterns, is central to discussions of geometrically frustrated systems, from water ice to binary and mixed-valence alloys, as well as numerous examples of frustrated magnets. The emergent Coulomb phase of lattice-based systems has been associated with divergence-free fields and the absence of long-range order. Here, we go beyond this paradigm, demonstrating that a Coulomb phase can emerge naturally as a persistent fluctuating background in an otherwise ordered system. To explain this behavior, we introduce the concept of the fragmentation of the field of magnetic moments into two parts, one giving rise to a magnetic monopole crystal, the other a magnetic fluid with all the characteristics of an emergent Coulomb phase. Our theory is backed up by numerical simulations, and we discuss its importance with regard to the interpretation of a number of experimental results

Confined coherence in quasi-one-dimensional metals

We present a functional renormalization group calculation of the effect of strong interactions on the shape of the Fermi surface of weakly coupled metallic chains. In the regime where the bare interchain hopping is small, we show that scattering processes involving large momentum transfers perpendicular to the chains can completely destroy the warping of the true Fermi surface, leading to a confined state where the renormalized interchain hopping vanishes and a coherent motion perpendicular to the chains is impossible.Comment: 4 RevTex pages, 5 figures,final version as published by PR

Briefing: UK Ministry of Defence Force Protection Engineering Programme

The Defence Science and Technology Laboratory sponsored, QinetiQ-led Force Protection Engineering Research Programme has two main strands, applied and underpinning research. The underpinning strand is led by Blastech Ltd. One focus of this research is into the response of geomaterials to threat loading. The programme on locally won fill is split into four main characterisation strands: high-stress (GPa) static pressure–volume; medium-rate pressure–volume (split Hopkinson bar); high-rate (flyer plate) pressure–volume; and unifying modelling research at the University of Sheffield, which has focused on developing a high-quality dataset for locally won fill in low and medium strain rates. With the test apparatus at Sheffield well-controlled tests can be conducted at both high strain rate and pseudo-static rates up to stress levels of 1 GPa. The University of Cambridge has focused on using one-dimensional shock experiments to examine high-rate pressure–volume relationships. Both establishments are examining the effect of moisture content and starting density on emergent rate effects. Blastech Ltd has been undertaking carefully controlled fragment impact experiments, within the dataspace developed by the Universities of Sheffield and Cambridge. The data from experiments are unified by the QinetiQ-led modelling team, to predict material behaviour and to derive a scalable locally won fill model for use in any situation

An independently fed log-periodic antenna for directed pulsed radiation

The development of an antenna capable of radiating a band-limited pulse with minimal distortion, negligible loss, and significant directivity is reported. A design was derived by modification of the conventional log-periodic dipole array to permit independent feeding of each dipole. This was modeled with a time-domain integral equation program and iterated to find a design that minimized phase dispersion across the operating band. The optimal design was realized in hardware, using a printed structure to feed the dipoles independently; this was located in the normal plane to prevent distortion of the radiated fields. When tested, the antenna was found to give a good quality radiated pulse in the main beam direction, with weaker and dispersed waveforms in other directions, indicating significant directive gain

Effect of two different participant information sheets on recruitment to a falls trial:an embedded randomised recruitment trial

Background/Aims: Recruitment to trials of intervention for older people who fall is challenging. Evidence suggests that the word falls has negative connotations for older people, and this may present a barrier to engaging with trials in this area. We therefore tested whether a participant information sheet that minimised reference to falls could improve recruitment rates. Methods: We conducted a study within a trial, embedded within a randomised controlled trial of vitamin K versus placebo to improve postural sway in patients aged 65 and over with a history of falls. Potential participants were identified from primary care lists in 14 practices and were randomised to receive either a standard participant information sheet or an information sheet minimising use of the word falls, instead focussing on maintenance of health, fitness and balance. The primary outcome for this embedded trial was the proportion of responses expressing interest in participating received in each arm. Secondary outcomes were the proportion of those contacted attending a screening visit, consenting at screening, and the proportion contacted who were randomised into the main trial. Results: In all, 4145 invitations were sent, with an overall response rate of 444 (10.7%). In all, 2148 individuals received the new information sheet (minimising reference to falls); 1997 received the standard information sheet. There was no statistically significant difference in response rate between those individuals sent the new information sheet and those sent the standard information sheet (10.1% vs 11.4%; difference 1.3% (95% confidence interval -0.6% to 3.2%); p = 0.19). Similarly, we found no statistically significant difference between the percentage of those who attended and consented at screening in the two groups (2.1% vs 2.7%; difference 0.6% (95% confidence interval: -0.4% to 1.6%); p = 0.20), and no statistically significant difference between the percentage randomised in the two groups (2.0% vs 2.6%; difference 0.6% (95% confidence interval -0.4% to 1.6%); p = 0.20). Conclusions: Use of a participant information sheet minimising reference to falls did not lead to a greater response rate in this trial targeting older people with a history of falls.</p