The inertial subrange in turbulent pipe flow: centreline

The inertial-subrange scaling of the axial velocity component is examined for the centreline of turbulent pipe flow for Reynolds numbers in the range 249⩽Reλ⩽986. Estimates of the dissipation rate are made by both integration of the one-dimensional dissipation spectrum and the third-order moment of the structure function. In neither case does the non-dimensional dissipation rate asymptote to a constant; rather than decreasing, it increases indefinitely with Reynolds number. Complete similarity of the inertial range spectra is not evident: there is little support for the hypotheses of Kolmogorov (Dokl. Akad. Nauk SSSR, vol. 32, 1941a, pp. 16–18; Dokl. Akad. Nauk SSSR, vol. 30, 1941b, pp. 301–305) and the effects of Reynolds number are not well represented by Kolmogorov’s ‘extended similarity hypothesis’ (J. Fluid Mech., vol. 13, 1962, pp. 82–85). The second-order moment of the structure function does not show a constant value, even when compensated by the extended similarity hypothesis. When corrected for the effects of finite Reynolds number, the third-order moments of the structure function accurately support the ‘four-fifths law’, but they do not show a clear plateau. In common with recent work in grid turbulence, non-equilibrium effects can be represented by a heuristic scaling that includes a global Reynolds number as well as a local one. It is likely that non-equilibrium effects appear to be particular to the nature of the boundary conditions. Here, the principal effects of the boundary conditions appear through finite turbulent transport at the pipe centreline, which constitutes a source or a sink at each wavenumber

Anomalous Nernst effect in Co2MnSi thin films

Separation of the anomalous Nernst and spin Seebeck voltages in bilayer devices is often problematic when both layers are metallic, and the anomalous Nernst effect (ANE) becomes non-negligible. Co2MnSi, a strong candidate for the spin generator in spin Seebeck devices, is a predicted half-metal with 100% spin polarisation at the Fermi energy, however, typically B2 or L21 order is needed to achieve this. We demonstrate the optimisation of thin film growth of Co2MnSi on glass, where choice of deposition and annealing temperature can promote various ordered states. The contribution from the ANE is then investigated to inform futuremeasurements of the spin Seebeck. A maximum ANE coefficient of 0.662 µV K−1 is found for an A2 disordered polycrystalline Co2MnSi film. This value is comparable to ordered Heuslerthin films deposited onto single crystal substrates but obtained at a far lower fabrication temperature and material cost.</div

Forced evictions and their social and health impacts in Southern Somalia: a qualitative study in Mogadishu Internally Displaced Persons (IDP) camps

Background: Forced evictions are common in conflict-affected settings. More than 500 internally displaced persons (IDPs) are evicted daily in Mogadishu. Context specific research is necessary to inform responsive humanitarian interventions and to monitor the effective- ness of these interventions on IDPs health. Objective: This study explored the causes of forced evictions and their health impacts among IDPs in southern Somalia. Methods: We used a qualitative approach, conducting 20 semi-structured interviews, six key informant interviews and four focus group discussions. We used maximum variation sampling to include a wide range of participants and used the framework approach and Nvivo software to analyse the data. Results: In this context, landlords often rented land without proper tenure agreements, resulting in risk of forced evictions. Informal tenure agreements led to fluctuations in rent, and IDPs were evicted because tenancy laws were inadequate and failed to protect their rights. IDP settlements often increased the value of land by clearing scrub, and landlords often sought to profit from this by evicting IDPs at short notice if a buyer was found for the land. The effect of eviction on an already marginalised population was wide ranging, increasing their exposure to violence, loss of assets, sexual assault, disruption of livelihoods, loss of social networks, and family separation. Evicted IDPs reported health issues such as diarrhoea, malaria, pneumonia, measles and skin infections, as well as stress, anxiety, psychological distress and trauma. Conclusion: Forced evictions remain one of the biggest challenges for IDPs as they exacerbate existing vulnerabilities. Prioritizing implementation of legal protection for IDP tenure rights is necessary to prevent unlawful evictions of IDPs. Humanitarian agencies should aim to respond more effectively to protect evictees and provide support to prevent poor health outcomes. Further quantitative research is needed to examine the relationship between forced evictions and health outcomes

Integrating trans-disciplinary approaches: joined-up working in urban regeneration.

This paper questions the relationship between biodiversity, planning and governance and highlights physical and organizational barriers that can prevent change. Trans-disciplinary approaches to evaluating biodiverse urban environments are discussed and analysed with particular reference to the role of environmental public art and community engagement projects within urban regeneration. Public art has been integrated into the regeneration of cities. Public artists are capable of delivering interesting ‘greening projects’ that involve local communities in the processes. Such projects appeal to local authorities because they are perceived to address objectives within authority¹s social and environmental policies. An illustrative study is provided: a multidisciplinary team were commissioned to map four miles of the Leeds/Liverpool canal as part of Liverpool Biennial’s Urbanism 2009. The team, led by an artist and a plant ecologist, collected data over six months in the spring and summer of 2009. This data included measurements of the biodiversity of the area, recording and categorising human activity, patterns of dog fouling, ‘landscape preference’ using selected canal-side landscapes, and detailed data on the ‘barrier constructs’ (fencing, walls etc) along the canal which link back to patterns of human activity and can be further related to aesthetics and environmental psychology. The conclusions were that this stretch of urban waterway is an ecological gem within an area of urban deprivation, but for the gem to attract people from across all demographics - to enjoy and foster ongoing use and respect for the environment, changes need to occur in the way that agencies and professionals work together. This vision can only realistically be achieved if professionals from all relevant agencies work collectively, pooling resources and expertise. A series of recommendations for action are suggested: it is not so much about community cohesion - a sense of community in the built environment - but cohesion amongst agencies and professionals

PIXE analysis of MOUDI filters

This paper will present results from a series of analyses performed on 8-stage Micro Orifice Uniform Deposit Impactor (MOUDI) sampling substrates using accelerator-based Particle Induced X-ray Emission (PIXE) analyses. These experiments aimed to better understand the influence of aerosol deposition on each of the MOUDI stages on the PIXE analysis results. copyright © 2011-Clean Air Society of Australia & New Zealan

Phylogeography of Japanese encephalitis virus:genotype is associated with climate

The circulation of vector-borne zoonotic viruses is largely determined by the overlap in the geographical distributions of virus-competent vectors and reservoir hosts. What is less clear are the factors influencing the distribution of virus-specific lineages. Japanese encephalitis virus (JEV) is the most important etiologic agent of epidemic encephalitis worldwide, and is primarily maintained between vertebrate reservoir hosts (avian and swine) and culicine mosquitoes. There are five genotypes of JEV: GI-V. In recent years, GI has displaced GIII as the dominant JEV genotype and GV has re-emerged after almost 60 years of undetected virus circulation. JEV is found throughout most of Asia, extending from maritime Siberia in the north to Australia in the south, and as far as Pakistan to the west and Saipan to the east. Transmission of JEV in temperate zones is epidemic with the majority of cases occurring in summer months, while transmission in tropical zones is endemic and occurs year-round at lower rates. To test the hypothesis that viruses circulating in these two geographical zones are genetically distinct, we applied Bayesian phylogeographic, categorical data analysis and phylogeny-trait association test techniques to the largest JEV dataset compiled to date, representing the envelope (E) gene of 487 isolates collected from 12 countries over 75 years. We demonstrated that GIII and the recently emerged GI-b are temperate genotypes likely maintained year-round in northern latitudes, while GI-a and GII are tropical genotypes likely maintained primarily through mosquito-avian and mosquito-swine transmission cycles. This study represents a new paradigm directly linking viral molecular evolution and climate

A Fokker-Planck formalism for diffusion with finite increments and absorbing boundaries

Gaussian white noise is frequently used to model fluctuations in physical systems. In Fokker-Planck theory, this leads to a vanishing probability density near the absorbing boundary of threshold models. Here we derive the boundary condition for the stationary density of a first-order stochastic differential equation for additive finite-grained Poisson noise and show that the response properties of threshold units are qualitatively altered. Applied to the integrate-and-fire neuron model, the response turns out to be instantaneous rather than exhibiting low-pass characteristics, highly non-linear, and asymmetric for excitation and inhibition. The novel mechanism is exhibited on the network level and is a generic property of pulse-coupled systems of threshold units.Comment: Consists of two parts: main article (3 figures) plus supplementary text (3 extra figures

Photoelectrochemical properties of mesoporous NiOx deposited on technical FTO via nanopowder sintering in conventional and plasma atmospheres

Nanoporous nickel oxide (NiO x ) has been deposited with two different procedures of sintering (CS and RDS). Both samples display solid state oxidation at about 3.1 V vs Li+/Li. Upon sensitization of CS/RDS NiO x with erythrosine b (ERY), nickel oxide oxidation occurs at the same potential. Impedance spectroscopy revealed a higher charge transfer resistance for ERY-sensitized RDS NiO x with respect to sensitized CS NiO x . This was due to the chemisorption of a larger amount of ERY on RDS with respect to CS NiO x . Upon illumination the photoinduced charge transfer between ERY layer and NiO x could be observed only with oxidized CS. Photoelectrochemical effects of sensitized RDS NiO x were evidenced upon oxide reduction. With the addition of iodine RDS NiOx electrodes could give the reduction iodine → iodide in addition to the reduction of RDS NiO x . p-type dye sensitized solar cells were assembled with RDS NiO x photocathodes sensitized either by ERY or Fast Green. Resulting overall efficiencies ranged between 0.02 and 0.04 % upon irradiation with solar spectrum simulator (Iin : 0.1 W cm −2 )

The Dawn of Open Access to Phylogenetic Data

The scientific enterprise depends critically on the preservation of and open access to published data. This basic tenet applies acutely to phylogenies (estimates of evolutionary relationships among species). Increasingly, phylogenies are estimated from increasingly large, genome-scale datasets using increasingly complex statistical methods that require increasing levels of expertise and computational investment. Moreover, the resulting phylogenetic data provide an explicit historical perspective that critically informs research in a vast and growing number of scientific disciplines. One such use is the study of changes in rates of lineage diversification (speciation - extinction) through time. As part of a meta-analysis in this area, we sought to collect phylogenetic data (comprising nucleotide sequence alignment and tree files) from 217 studies published in 46 journals over a 13-year period. We document our attempts to procure those data (from online archives and by direct request to corresponding authors), and report results of analyses (using Bayesian logistic regression) to assess the impact of various factors on the success of our efforts. Overall, complete phylogenetic data for ~60% of these studies are effectively lost to science. Our study indicates that phylogenetic data are more likely to be deposited in online archives and/or shared upon request when: (1) the publishing journal has a strong data-sharing policy; (2) the publishing journal has a higher impact factor, and; (3) the data are requested from faculty rather than students. Although the situation appears dire, our analyses suggest that it is far from hopeless: recent initiatives by the scientific community -- including policy changes by journals and funding agencies -- are improving the state of affairs