Assessing the contribution of vegetation to slope stability

Many embankments and cuttings associated with the transportation infrastructure in the UK are only marginally stable. Engineering techniques such as soil nailing, geosynthetic reinforcement, improved drainage and ground improvement by stabilisation are available to improve stability but the cost can be high. A lower cost solution may be to utilise vegetation, either self seeded or planted. The benefits and drawbacks associated with vegetation have been the subject of some debate. The problems caused by vegetation in relation to building foundations are well documented and confirm that vegetation can have very significant influences on geotechnical parameters. Appropriate properly maintained vegetation can have the same significant influence to help provide additional stability to soil slopes. This paper considers the potential engineering influences of vegetation and how it can be characterised on site within a geotechnical framework for stability assessments. The direct reinforcement available from the roots of trees and shrubs is identified as providing one of the most significant contributions to slope stability. Case studies in the UK, Greece and Italy demonstrate how results from in-situ root pull out tests may be used to estimate the potential reinforcement forces available from the roots. A scheme is presented to designate zones of influence within the soil according to the size and nature of the vegetation

Organisational justice and health of employees: prospective cohort study

Aims: To examine the association between components of organisational justice (that is, justice of decision making procedures and interpersonal treatment) and health of employees.Methods: The Poisson regression analyses of recorded all-cause sickness absences with medical certificate and the logistic regression analyses of minor psychiatric morbidity, as assessed by the General Health Questionnaire, and poor self rated health status were based on a cohort of 416 male and 3357 female employees working during 1998-2000 in 10 hospitals in Finland.Results: Low versus high justice of decision making procedures was associated with a 41% higher risk of sickness absence in men (rate ratio (RR) 1.4, 95% confidence interval (CI) 1.1 to 1.8), and a 12% higher risk in women (RR 1.1, 95% CI 1.0 to 1.2) after adjustment for baseline characteristics., The corresponding odds ratios (OR) for minor psychiatric morbidity were 1.6 (95% CI 1.0 to 2.6) in men and 1.4 (95% CI 1.2 to 1.7) in women, and for self rated health 1.4 in both sexes. In interpersonal treatment, low justice increased the risk of sickness absence (RR 1.3 (95% CI 1.0 to 1.6) and RR 1.2 (95% CI 1.2 to 1.3) in men and women respectively), and minor psychiatric morbidity (OR 1.2 in both sexes). These figures largely Persisted after control for other risk factors (for example, job control, workload, social support, and hostility) and they were replicated in initially healthy subcohorts. No evidence was found to support the hypothesis that organisational justice would represent a consequence of health (reversed causality).Conclusions: This is the first longitudinal study to show that the extent to which people are treated with justice in workplaces independently predicts their health

OpenCL + OpenSHMEM Hybrid Programming Model for the Adapteva Epiphany Architecture

There is interest in exploring hybrid OpenSHMEM + X programming models to extend the applicability of the OpenSHMEM interface to more hardware architectures. We present a hybrid OpenCL + OpenSHMEM programming model for device-level programming for architectures like the Adapteva Epiphany many-core RISC array processor. The Epiphany architecture comprises a 2D array of low-power RISC cores with minimal uncore functionality connected by a 2D mesh Network-on-Chip (NoC). The Epiphany architecture offers high computational energy efficiency for integer and floating point calculations as well as parallel scalability. The Epiphany-III is available as a coprocessor in platforms that also utilize an ARM CPU host. OpenCL provides good functionality for supporting a co-design programming model in which the host CPU offloads parallel work to a coprocessor. However, the OpenCL memory model is inconsistent with the Epiphany memory architecture and lacks support for inter-core communication. We propose a hybrid programming model in which OpenSHMEM provides a better solution by replacing the non-standard OpenCL extensions introduced to achieve high performance with the Epiphany architecture. We demonstrate the proposed programming model for matrix-matrix multiplication based on Cannon's algorithm showing that the hybrid model addresses the deficiencies of using OpenCL alone to achieve good benchmark performance.Comment: 12 pages, 5 figures, OpenSHMEM 2016: Third workshop on OpenSHMEM and Related Technologie

ADAR-mediated RNA editing suppresses sleep by acting as a brake on glutamatergic synaptic plasticity.

It has been postulated that synaptic potentiation during waking is offset by a homoeostatic reduction in net synaptic strength during sleep. However, molecular mechanisms to support such a process are lacking. Here we demonstrate that deficiencies in the RNA-editing gene Adar increase sleep due to synaptic dysfunction in glutamatergic neurons in Drosophila. Specifically, the vesicular glutamate transporter is upregulated, leading to over-activation of NMDA receptors, and the reserve pool of glutamatergic synaptic vesicles is selectively expanded in Adar mutants. Collectively these changes lead to sustained neurotransmitter release under conditions that would otherwise result in synaptic depression. We propose that a shift in the balance from synaptic depression towards synaptic potentiation in sleep-promoting neurons underlies the increased sleep pressure of Adar-deficient animals. Our findings provide a plausible molecular mechanism linking sleep and synaptic plasticity

Organisational downsizing, sickness absence, and mortality: 10-town prospective cohort study

Objective To examine whether downsizing, the reduction of personnel in organisations, is a predictor of increased sickness absence and mortality among employees.Design Prospective cohort study over 7.5 years of employees grouped into categories on the basis of reductions of personnel in their occupation and workplace: no downsizing ( 18%).Setting Four towns in Finland.Participants 5909 male and 16 521 female municipal employees, aged 19-62 years, who kept their jobs.Main outcome measures Annual sickness absence rate based on employers' records before and after downsizing by employment contract; all cause and cause specific mortality obtained from the national mortality register.Results Major downsizing was associated with an increase in sickness absence (P for trend < 0.001) in permanent employees but not in temporary employees. The extent of downsizing was also associated with cardiovascular deaths (P for trend < 0.01) but not with deaths from other causes. Cardiovascular mortality was 2.0 (95% confidence interval 1.0 to 3.9) times higher after major downsizing than after no downsizing. Splitting the follow up period into two halves showed a 5.1 (1.4 to 19.3) times increase in cardiovascular mortality for major downsizing during the first four years after downsizing. The corresponding hazard ratio was 1.4 (0.6 to 3.1) during the second half of follow up.Conclusion Organisational downsizing may increase sickness absence and the risk of death from cardiovascular disease in employees who keep their jobs

Giant suppression of the Drude conductivity due to quantum interference in disordered two-dimensional systems

Temperature and magnetic field dependences of the conductivity in heavily doped, strongly disordered two-dimensional quantum well structures GaAs/In$_x$Ga$_{1-x}$As/GaAs are investigated within wide conductivity and temperature ranges. Role of the interference in the electron transport is studied in the regimes when the phase breaking length $L_\phi$ crosses over the localization length $\xi\sim l\exp{(\pi k_Fl/2)}$ with lowering temperature, where $k_F$ and $l$ are the Fermi quasimomentum and mean free path, respectively. It has been shown that all the experimental data can be understood within framework of simple model of the conductivity over delocalized states. This model differs from the conventional model of the weak localization developed for $k_Fl\gg 1$ and $L_\phi\ll\xi$ by one point: the value of the quantum interference contribution to the conductivity is restricted not only by the phase breaking length $L_\phi$ but by the localization length $\xi$ as well. We show that just the quantity $(\tau_\phi^\ast)^{-1}=\tau_\phi^{-1}+\tau_\xi^{-1}$ rather than $\tau_\phi^{-1}$, where $\tau_\phi\propto T^{-1}$ is the dephasing time and $\tau_\xi\sim\tau\exp(\pi k_F l)$, is responsible for the temperature and magnetic field dependences of the conductivity over the wide range of temperature and disorder strength down to the conductivity of order $10^{-2} e^2/h$.Comment: 11 pages, 15 figure