Quantification of airborne road-side pollution carbon nanoparticles

Roadside diesel particulate matter (DPM) has been collected using a P-Trak particle counter with modified inlet filter. The P-Trak monitor assesses ultrafine particle number in real-time rather than accumulated PM mass over a period of time, which is important for DPM where the particles are often <100nm in size. Collected pollution particulate matter was analysed by SEM and TEM, quantifying particle size, morphology and size distribution. The primary carbon nanoparticles form complex fractal aggregates with open porous morphologies and evidence of secondary carbon deposition. For the chosen collection sites, occasional but significantly larger mineral and fibrous particles were identified. The assessment of airborne particles by mass collection (TEOM), particle-number (P-Trak) and TEM methods is discussed

Structure and colour in triangle-free graphs

Motivated by a recent conjecture of the first author, we prove that every properly coloured triangle-free graph of chromatic number $\chi$ contains a rainbow independent set of size $\lceil\frac12\chi\rceil$. This is sharp up to a factor $2$. This result and its short proof have implications for the related notion of chromatic discrepancy. Drawing inspiration from both structural and extremal graph theory, we conjecture that every triangle-free graph of chromatic number $\chi$ contains an induced cycle of length $\Omega(\chi\log\chi)$ as $\chi\to\infty$. Even if one only demands an induced path of length $\Omega(\chi\log\chi)$, the conclusion would be sharp up to a constant multiple. We prove it for regular girth $5$ graphs and for girth $21$ graphs. As a common strengthening of the induced paths form of this conjecture and of Johansson's theorem (1996), we posit the existence of some $c >0$ such that for every forest $H$ on $D$ vertices, every triangle-free and induced $H$-free graph has chromatic number at most $c D/\log D$. We prove this assertion with `triangle-free' replaced by `regular girth $5$'.Comment: 12 pages; in v2 one section was removed due to a subtle erro

Contemporary carbon fluxes do not reflect the long-term carbon balance for an Atlantic blanket bog

Peatlands are one of the largest terrestrial stores of carbon. Carbon exchange in peatlands is often assessed solely by measurement of contemporary fluxes; however, these fluxes frequently indicate a much stronger sink strength than that measured by the rate of C accumulation in the peat profile over longer timescales. Here we compare profile-based measurements of C accumulation with the published net ecosystem C balance for the largest peatland area in Britain, the Flow Country of northern Scotland. We estimate the long-term rate of C accumulation to be 15.4 g C m−2 yr−1 for a site where a recent eddy covariance study has suggested contemporary C uptake more than six times greater (99.37 g C m−2 yr−1). Our estimate is supported by two further long-term C accumulation records from nearby sites which give comparable results. We demonstrate that a strong contemporary C sink strength may not equate to a strong long-term sink and explore reasons for this disparity. We recommend that contemporary C sequestration should be viewed in the context of the long-term ecological drivers, such as fires, ecohydrological feedbacks and the changing quality of litter inputs

Effects of air pollution and the introduction of the London Low Emission Zone on the prevalence of respiratory and allergic symptoms in schoolchildren in East London: a sequential cross-sectional study

The adverse effects of traffic-related air pollution on children’s respiratory health have been widely reported, but few studies have evaluated the impact of traffic-control policies designed to reduce urban air pollution. We assessed associations between traffic-related air pollutants and respiratory/allergic symptoms amongst 8–9 year-old schoolchildren living within the London Low Emission Zone (LEZ). Information on respiratory/allergic symptoms was obtained using a parent-completed questionnaire and linked to modelled annual air pollutant concentrations based on the residential address of each child, using a multivariable mixed effects logistic regression analysis. Exposure to traffic-related air pollutants was associated with current rhinitis: NOx (OR 1.01, 95% CI 1.00–1.02), NO2 (1.03, 1.00–1.06), PM10 (1.16, 1.04–1.28) and PM2.5 (1.38, 1.08–1.78), all per μg/m3 of pollutant, but not with other respiratory/allergic symptoms. The LEZ did not reduce ambient air pollution levels, or affect the prevalence of respiratory/allergic symptoms over the period studied. These data confirm the previous association between traffic-related air pollutant exposures and symptoms of current rhinitis. Importantly, the London LEZ has not significantly improved air quality within the city, or the respiratory health of the resident population in its first three years of operation. This highlights the need for more robust measures to reduce traffic emissions

Europe’s perennial "outsiders": a processual approach to Roma stigmatization and ghettoization

This paper draws on the theoretical work of Norbert Elias and Loïc Wacquant in seeking to understand the stigmatized and marginalized position of the Roma population within Europe. The paper argues that the persistent persecution of Roma, reflected in social policy, cannot be understood without reference to long-term social processes, which shape the nature of the asymmetric power relations between Roma and non-Roma. Elias's theory of established-outsider relations is applied at the intra-state European level in arguing that Roma constitute a cross-border "outsider" group; with their intense stigmatization explained and perpetuated by a common set of collective fantasies which are maintained through complex group processes of disidentification, and which result in Roma being seen as of lesser human worth. Wacquant's theoretical concept of the "ghetto" is then drawn upon to show how the manifestations of stigmatization for the stigmatized are at once psychological, social and spatial. The paper suggests that the synthesis of the two theorists' relational, theoretical concepts allows for an approach that can expose the way in which power is exercised within and through group relations. Such an approach emphasizes the centrality of the interdependence between Roma and non-Roma, and the fluctuating power balance that characterises that relationship across time and space. The paper concludes that, while existing research focused on policy and outcomes is useful in understanding the negative contemporary experiences of Roma populations, they need to be understood in the context of wider social processes and historical continuities in seeking to elucidate how these processes shape policies and contribute to social and spatial marginalization

Reduced Quantitative Ultrasound Bone Mineral Density in HIV-Infected Patients on Antiretroviral Therapy in Senegal

Background: Bone status in HIV-infected patients on antiretroviral treatment (ART) is poorly documented in resource-limited settings. We compared bone mineral density between HIV-infected patients and control subjects from Dakar, Senegal. Methods: A total of 207 (134 women and 73 men) HIV-infected patients from an observational cohort in Dakar (ANRS 1215) and 207 age-and sex-matched controls from the general population were enrolled. Bone mineral density was assessed by quantitative ultrasound (QUS) at the calcaneus, an alternative to the reference method (i.e. dual X-absorptiometry), often not available in resource-limited countries. Results: Mean age was 47.0 (+/- 8.5) years. Patients had received ART for a median duration of 8.8 years; 45% received a protease inhibitor and 27% tenofovir; 84% had undetectable viral load. Patients had lower body mass index (BMI) than controls (23 versus 26 kg/m(2), P<0.001). In unadjusted analysis, QUS bone mineral density was lower in HIV-infected patients than in controls (difference: -0.36 standard deviation, 95% confidence interval (CI): -0.59;-0.12, P = 0.003). Adjusting for BMI, physical activity, smoking and calcium intake attenuated the difference (-0.27, CI: -0.53; -0.002, P = 0.05). Differences in BMI between patients and controls explained a third of the difference in QUS bone mineral density. Among patients, BMI was independently associated with QUS bone mineral density (P<0.001). An association between undetectable viral load and QUS bone density was also suggested (beta = 0.48, CI: 0.02; 0.93; P = 0.04). No association between protease inhibitor or tenofovir use and QUS bone mineral density was found. Conclusion: Senegalese HIV-infected patients had reduced QUS bone mineral density in comparison with control subjects, in part related to their lower BMI. Further investigation is needed to clarify the clinical significance of these observations

Bipartite induced density in triangle-free graphs

Contains fulltext : 219969.pdf (publisher's version ) (Open Access

Equilibrium Solutions in Static Decision Problems with Random Coefficients in the Quadratic Cost

P. E. Caines. “A note on the consistency of maximum Likelihood estimates for finite families of stochastic processes, ” Ann &amp; of Sfarirtics, vol. 3, no. 2, pp. 539-546. Y. Baram and N. R. Sandell, Jr.. “Consistent estimation on finite parameter sets mth application to linear system identification. ” IEEE Tram. AII~O~I. Contr., vol