Quantum oscillations of nitrogen atoms in uranium nitride

The vibrational excitations of crystalline solids corresponding to acoustic or optic one phonon modes appear as sharp features in measurements such as neutron spectroscopy. In contrast, many-phonon excitations generally produce a complicated, weak, and featureless response. Here we present time-of-flight neutron scattering measurements for the binary solid uranium nitride (UN), showing well-defined, equally-spaced, high energy vibrational modes in addition to the usual phonons. The spectrum is that of a single atom, isotropic quantum harmonic oscillator and characterizes independent motions of light nitrogen atoms, each found in an octahedral cage of heavy uranium atoms. This is an unexpected and beautiful experimental realization of one of the fundamental, exactly-solvable problems in quantum mechanics. There are also practical implications, as the oscillator modes must be accounted for in the design of generation IV nuclear reactors that plan to use UN as a fuel.Comment: 25 pages, 10 figures, submitted to Nature Communications, supplementary information adde

Making Birmingham a Flood Resilient City: Challenges and Opportunities

The city of Birmingham has experienced a number of significant flooding events in the past two decades. The impacts of these flood events include physical damage to critical infrastructure, as well as significant losses caused by business interruption and general disruption to communities. Human losses and impacts can be life changing. This study identifies the current challenges and opportunities of managing flood risk in the city of Birmingham, drawing on a desk-based account of current flood risk management (FRM) practice and diagnostic evidence. This interrogation adopts the use of a ‘flood resilience circle model’ to consider ways to address the challenges in a methodological manner aligned to an integrated approach to flood risk management. Solutions aligned to the key FRM stages of prevention, preparation, response and recovery are provided. The findings will be of interest to policy makers and decision makers on how to address current weaknesses in FRM practices towards the prospect of a sustainable approach that improves the resilience of the city and delivers multiple benefits. Recommendations made include the adoption of a blue-green systems approach, the development of a new communication strategy aligned to motivating behaviour change, and improved flood forecasting especially for surface water flooding

Variable Sodium Absorption in a Low-Extinction Type Ia Supernova

Recent observations have revealed that some Type Ia supernovae exhibit narrow, time-variable Na I D absorption features. The origin of the absorbing material is controversial, but it may suggest the presence of circumstellar gas in the progenitor system prior to the explosion, with significant implications for the nature of the supernova progenitors. We present the third detection of such variable absorption, based on six epochs of high-resolution spectroscopy of the Type Ia supernova SN 2007le from Keck and the HET. The data span ~3 months, from 5 days before maximum light to 90 days after maximum. We find that one component of the Na D absorption lines strengthened significantly with time, indicating a total column density increase of ~2.5 x 10^12 cm^-2. The changes are most prominent after maximum light rather than at earlier times when the UV flux from the SN peaks. As with SN 2006X, we detect no change in the Ca II H&K lines over the same time period, rendering line-of-sight effects improbable and suggesting a circumstellar origin for the absorbing material. Unlike the previous two SNe exhibiting variable absorption, SN 2007le is not highly reddened (E_B-V = 0.27 mag), also pointing toward circumstellar rather than interstellar absorption. Photoionization models show that the data are consistent with a dense (10^7 cm^-3) cloud or clouds of gas located ~0.1 pc from the explosion. These results broadly support the single-degenerate scenario previously proposed to explain the variable absorption, with mass loss from a nondegenerate companion star responsible for providing the circumstellar gas. We also present tentative evidence for narrow Halpha emission associated with the SN, which will require followup observations at late times to confirm. [abridged]Comment: 16 pages, 10 figures (8 in color), 5 tables. Accepted for publication in Ap

Constraints on the Progenitor System of the Type Ia Supernova SN 2011fe/PTF11kly

Type Ia supernovae (SNe) serve as a fundamental pillar of modern cosmology, owing to their large luminosity and a well-defined relationship between light-curve shape and peak brightness. The precision distance measurements enabled by SNe Ia first revealed the accelerating expansion of the universe, now widely believed (though hardly understood) to require the presence of a mysterious "dark" energy. General consensus holds that Type Ia SNe result from thermonuclear explosions of a white dwarf (WD) in a binary system; however, little is known of the precise nature of the companion star and the physical properties of the progenitor system. Here we make use of extensive historical imaging obtained at the location of SN 2011fe/PTF11kly, the closest SN Ia discovered in the digital imaging era, to constrain the visible-light luminosity of the progenitor to be 10-100 times fainter than previous limits on other SN Ia progenitors. This directly rules out luminous red giants and the vast majority of helium stars as the mass-donating companion to the exploding white dwarf. Any evolved red companion must have been born with mass less than 3.5 times the mass of the Sun. These observations favour a scenario where the exploding WD of SN 2011fe/PTF11kly, accreted matter either from another WD, or by Roche-lobe overflow from a subgiant or main-sequence companion star.Comment: 22 pages, 6 figures, submitte

Effective board governance of safe care: a (theoretically underpinned) cross-sectioned examination of the breadth and depth of relationships through national quantitative surveys and in-depth qualitative case studies

Background: Recent high-profile reports into serious failings in the quality of hospital care in the NHS raise concerns over the ability of trust boards to discharge their duties effectively. Objectives: Our study aimed to generate theoretically grounded empirical evidence on the associations between board governance, patient safety processes and patient-centred outcomes. The specific aims were as follows: (1) to identify the types of governance activities undertaken by hospital trust boards in the English NHS with regard to ensuring safe care in their organisation; (2) in foundation trusts, to explore the role of boards and boards of governors with regards to the oversight of patient safety in their organisation; (3) to assess the association between particular hospital trust board oversight activities and patient safety processes and clinical outcomes; (4) to identify the facilitators and barriers to developing effective hospital trust board governance of safe care; and (5) to assess the impact of external commissioning arrangements and incentives on hospital trust board oversight of patient safety. Methods: The study comprised three distinct but interlocking strands: (1) a narrative systematic review in order to describe, interpret and synthesise key findings and debates concerning board oversight of patient safety; (2) in-depth mixed-methods case studies in four organisations to assess the impact of hospital board governance and external incentives on patient safety processes and outcomes; and (3) two national surveys exploring board management in NHS acute and specialist hospital trusts in England, and relating board characteristics to whole-organisation outcomes. Results: A very high proportion of trust boards reported the kinds of desirable characteristics and board-related processes that research says may be associated with higher performance. Our analysis of the symbolic aspects of board activities highlights the role and differences in local processes of organising the governance of patient safety. Most boards do allocate considerable amount of time to discussing patient safety and quality-related issues and were using a wide range of hard performance metrics and soft intelligence to monitor its organisation with regard to patient safety. Although the board of governors is generally perceived to be well-meaning, they were also considered to be being largely ineffective in helping to promote and deliver safer care for their organisations. We did not find any statistically significant relationship between board attributes (self-reported) and processes and any patient safety outcome measures. However, we did find a significant relationship between two dimensions of the Board Self-Assessment Questionnaire and two specific-and-related national staff survey organisational ‘process’ measures: (1) staff feeling safe to raise concerns about errors, near-misses and incidents and (2) staff feeling confident that their organisation would address their concerns, if raised. We also found that contracting and external financial incentives appeared to play only a relatively minor role in incentivising quality and safety improvement. Conclusions: Our research is the first large-scale mixed-methods study of hospital board activity and behaviour related to the oversight of patient safety in the English NHS and the key findings should be used to influence the design of future governance arrangements as well as the training and support of board. Funding: The National Institute for Health Research Health Services and Delivery Research programme

Know Yourself:An Adaptive Causal Network Model for Therapeutic Intervention for Regaining Cognitive Control

Part 6: Medical-Health SystemsInternational audienceLong term stress often causes depression and neuronal atrophies that in turn can lead to a variety of health problems. As a result of these cellular changes, also molecular changes occur. These changes, that include increase of glucocorticoids and decrease of the brain-derived neurotrophic factor, have the unfortunate effect that they decrease the cognitive abilities needed for the individual to solve the stressful situation. Such cognitive abilities like reappraisal and their adaptation mechanisms turn out to be substantially impaired while they are needed for regulation of the negative emotions. However, antidepressant treatments and some other therapies have proved to be quite effective for the strengthening of such cognitive abilities. This study introduces an adaptive causal network model for this phenomenon where a subject loses his or her cognitive abilities (negative metaplasticity) due to long-term stress and re-improve these cognitive abilities (positive metaplasticity) through mindfulness-based cognitive therapy (MBCT). Simulation results have been reported for demonstration of the phenomenon

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

Burden of Total and Cause-Specific Mortality Related to Tobacco Smoking among Adults Aged ≥45 Years in Asia: A Pooled Analysis of 21 Cohorts

Background:Tobacco smoking is a major risk factor for many diseases. We sought to quantify the burden of tobacco-smoking-related deaths in Asia, in parts of which men's smoking prevalence is among the world's highest.Methods and Findings:We performed pooled analyses of data from 1,049,929 participants in 21 cohorts in Asia to quantify the risks of total and cause-specific mortality associated with tobacco smoking using adjusted hazard ratios and their 95% confidence intervals. We then estimated smoking-related deaths among adults aged ≥45 y in 2004 in Bangladesh, India, mainland China, Japan, Republic of Korea, Singapore, and Taiwan-accounting for ∼71% of Asia's total population. An approximately 1.44-fold (95% CI = 1.37-1.51) and 1.48-fold (1.38-1.58) elevated risk of death from any cause was found in male and female ever-smokers, respectively. In 2004, active tobacco smoking accounted for approximately 15.8% (95% CI = 14.3%-17.2%) and 3.3% (2.6%-4.0%) of deaths, respectively, in men and women aged ≥45 y in the seven countries/regions combined, with a total number of estimated deaths of ∼1,575,500 (95% CI = 1,398,000-1,744,700). Among men, approximately 11.4%, 30.5%, and 19.8% of deaths due to cardiovascular diseases, cancer, and respiratory diseases, respectively, were attributable to tobacco smoking. Corresponding proportions for East Asian women were 3.7%, 4.6%, and 1.7%, respectively. The strongest association with tobacco smoking was found for lung cancer: A 3- to 4-fold elevated risk, accounting for 60.5% and 16.7% of lung cancer deaths, respectively, in Asian men and East Asian women aged ≥45 y.Conclusions:Tobacco smoking is associated with a substantially elevated risk of mortality, accounting for approximately 2 million deaths in adults aged ≥45 y throughout Asia in 2004. It is likely that smoking-related deaths in Asia will continue to rise over the next few decades if no effective smoking control programs are implemented.Please see later in the article for the Editors' Summary. © 2014 Zheng et al