Regional and local emissions in red river delta, Northern Vietnam

Fine (PM2.2) and coarse (PM2.2–10) particles concurrently collected in urban (Hanoi) and rural (Lucnam) areas were analyzed for ionic and elemental compositions to provide input for PMF receptor modeling of emission sources in the Red River Delta (RRD), a key economic development region in Vietnam. Long-range transport (LRT) aerosol, coal fly ash from major coal-fired plants in RRD, and marine aerosols are regional sources, which explain the minor variability of the mass concentrations of fine particles across the region. Local sources include soil/resuspended road dust, local coal fly ash, and biomass burning. Soil/resuspended road dust is the largest source component of coarse particles at the two sites. It is more abundant in Hanoi than in Lucnam reflecting the urban–rural contrast in traffic and construction works. Receptor models reveal the incorporation of secondary sulfate, nitrate, and ammonium into the various primary particles, i.e., soot, minerals, soil organic matter, and sea salt. Soot particles from LRT carry the largest amounts of sulfate and ammonium mass concentrations measured at the two sites. Based on receptor models, the yields and possible chemical forms of secondary sulfate, nitrate, and ammonium in different types of primary particles can be inferred

Evolutionary Repercussions of Avian Culling on Host Resistance and Influenza Virulence

Keeping pandemic influenza at bay is a global health priority. Of particular concern is the continued spread of the influenza subtype H5N1 in avian populations and the increasing frequency of transmission to humans. To decrease this threat, mass culling is the principal strategy for eradicating influenza in avian populations. Although culling has a crucial short-term epidemiological benefit, evolutionary repercussions on reservoir hosts and on the viral population have not been considered.To explore the epidemiological and evolutionary repercussions of mass avian culling, we combine population genetics and epidemiological influenza dynamics in a mathematical model parameterized by clinical, epidemiological, and poultry data. We model the virulence level of influenza and the selection on a dominant allele that confers resistance against influenza [1, 2] in a poultry population. Our findings indicate that culling impedes the evolution of avian host resistance against influenza. On the pathogen side of the coevolutionary race between pathogen and host, culling selects for heightened virulence and transmissibility of influenza.Mass culling achieves a short-term benefit at the expense of long-term detriments: a more genetically susceptible host population, ultimately greater mortality, and elevated influenza virulence

Risk assessment of exposure to particulate output of a demolition site.

Whilst vehicular and industrial contributions to the airborne particulate budget are well explored, the input due to building demolition is relatively unknown. Air quality is of importance to human health, and it is well known that composition of airborne particles can have a significant influence on both chronic and acute health effects. Road dust (RD) was collected before and after the demolition of a large building to elucidate changes in elemental profile. Rainfall and PM10 mass concentration data aided interpretation of the elemental data. Quantification of Al, As, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Rh, S, Si, Sn, Ti, V and Zn was carried out. It was found that only Al, K, Mg, Si and S increased in concentration across all size fractions after the building demolition. Risk assessment was then carried out on elements with applicable reference dose values to assess the potential health risks due to the demolition. Significant risk to children was observed for chromium and aluminium exposure. PM10, monitored 40 metres from the demolition site, indicated no abnormal concentrations during the demolition; however, rainfall data were shown to affect the concentration of PM10. The elemental data observed in this study could possibly indicate the role of increased sulphur concentrations (in this case as a result of the demolition) on the buffer capacity of RD, hence leaching metals into rainwater

Measurement of isomeric yield ratios for the Ho-nat(gamma,xn)Ho-164m,Ho-g;162m,Ho-g reactions in the bremsstrahlung energy region from 45 to 65 MeV

We have measured the isomeric yield ratios for the Ho-164m,Ho-g and the Ho-162m,Ho-g isomeric pairs formed via photonuclear reactions Ho-165(gamma,n)Ho-164m,Ho-g and Ho-165(gamma,3n)Ho-162m,Ho-g in the bremsstrahlung energy region from 45 to 65 MeV in steps of a dagger E = 5 MeV by the activation method. The induced gamma-activities of the irradiated holmium foils were measured by a coaxial high-purity germanium detector coupled to a PC-based multichannel analyzer. In order to improve the accuracy of the experimental results the necessary corrections were made. The experimental results at bremsstrahlung energies of 45, 50, 55, 60, and 65 MeV are 0.408 +/- A 0.027, 0.413 +/- A 0.027, 0.427 +/- A 0.029, 0.452 +/- A 0.032, and 0.448 +/- A 0.031 for the Ho-164m,Ho-g isomeric pair, and 0.587 +/- A 0.041, 0.624 +/- A 0.044, 0.652 +/- A 0.045, 0.637 +/- A 0.045, and 0.668 +/- A 0.046 for the Ho-162m,Ho-g isomeric pair, respectively. The present results are the first measurements at bremsstrahlung energies just above the giant dipole resonance region. The obtained results confirm the dependence of isomeric ratios on the incident photon energy as observed in some earlier experiments.X110sciescopu

Thermal neutron capture and resonance integral cross sections of Sc-45

The thermal neutron cross section (sigma(0)) and resonance integral (I-0) of the Sc-45(n,gamma)Sc-46 reaction have been measured relative to that of the Au-197(n,gamma)Au-198 reaction by means of the activation method. High-purity natural scandium and gold foils without and with a cadmium cover of 0.5 mm thickness were irradiated with moderated pulsed neutrons produced from the Pohang Neutron Facility (PNF). The induced activities in the activated foils were measured with a high purity germanium (HPGe) detector. In order to improve the accuracy of the experimental results the counting losses caused by the thermal (G(th)) and resonance (G(epi)) neutron self-shielding, the gamma-ray attenuation (F-g) and the true gamma-ray coincidence summing effects were made. In addition, the effect of non-ideal epithermal spectrum was also taken into account by determining the neutron spectrum shape factor (alpha). The thermal neutron cross-section and resonance integral of the Sc-45(n,gamma)Sc-46 reaction have been determined relative to the reference values of the Au-197(n,gamma)Au-198 reaction, with sigma(o,Au) = 98.65 +/- 0.09 barn and = 1550 +/- 28 barn. The present thermal neutron cross section has been determined to be sigma(o,Sc) = 27.5 +/- 0.8 barn. According to the definition of cadmium cut-off energy at 0.55 eV, the present resonance integral cross section has been determined to be I-o,I-Sc = 12.4 +/- 0.7 barn. The present results are compared with literature values and discussed. (C) 2015 Elsevier B.V. All rights reserved.1122sciescopu

Measurement of thermal neutron cross section and resonance integral for the Er-170(n,gamma)Er-171 reaction by using a gold monitor

The thermal neutron cross section (sigma(0)) and the resonance integral (I-0) of the reaction Er-170(n,gamma)Er-171 were measured by an activation method using a reaction Au-197(n,gamma)Au-198 as a single comparator. The high-purity natural erbium (Er-nat), and gold (Au-197) foils with and without Cd cover with the thickness of 0.5 mm were irradiated in a neutron field of the Pohang neutron facility. The induced activities in the activated foils were measured with a well calibrated coaxial HPGe detector. The thermal neutron cross section for the Er-170(n,gamma)Er-171 reaction has been determined to be sigma(0) = 7.80 +/- 0.35 barn, relative to the reference value of 98.65 +/- 0.09 barn for the Au-197(n,gamma)Au-198 reaction. By assuming the cadmium cutoff energy of 0.55 eV, the resonance integral for the Er-170(n,gamma)Er-171 reaction is I-0 = 40.4 +/- 2.8 barn, which is determined relative to the reference value of 1550 +/- 28 barn for the Au-197(n,gamma)Au-198 reaction. In order to improve the accuracy of the experimental results the epithermal neutron spectrum shape factor (alpha) was determined, and the necessary corrections for the counting loss caused by gamma-ray attenuation (F-g), the thermal neutron shelf-shielding (G(th)), the resonance neutron self-shielding (G(epi)) effects, the gamma-ray coincidence summing effect, as well as neutron flux fluctuation. The present results are compared with the reference data and discussed. (C) 2013 Elsevier B.V. All rights reserved.X110sciescopu