The Effect of Heat and Free Chlorine Treatments on the Surface Properties of Murine Norovirus

Heat and free chlorine are among the most efficient and commonly used treatments to inactivate enteric viruses, but their global inactivation mechanisms have not been elucidated yet. These treatments have been shown to affect at least the capsid proteins of viruses and thus may affect the surface properties (i.e. electrostatic charge and hydrophobicity) of such particles. Our aim was to study the effects of heat and free chlorine on surface properties for a murine norovirus chosen as surrogate for human norovirus. No changes in the surface properties were observed with our methods for murine norovirus exposed to free chlorine. Only the heat treatment led to major changes in the surface properties of the virus with the expression of hydrophobic domains at the surface of the particles after exposure to a temperature of 55 °C. No modification of the expression of hydrophobic domains occurred after exposure to 60 °C, and the low hydrophobic state exhibited by infectious and inactivated particles after exposure to 60 °C appeared to be irreversible for inactivated particles only, which may provide a means to discriminate infectious from inactivated murine noroviruses. When exposed to a temperature of 72 °C or to free chlorine at a concentration of 50 mg/L, the genome became available for RNases.     

Afforestation opportunities when stand productivity is driven by a high risk of natural disturbance: a review of the open lichen woodland in the eastern boreal forest of Canada

Afforestation has the potential to offset the increased emission of atmospheric carbon dioxide and has therefore been proposed as a strategy to mitigate climate change. Here we review the opportunities for carbon (C) offsets through open lichen woodland afforestation in the boreal forest of eastern Canada as a case study, while considering the reversal risks (low productivity, fires, insect outbreaks, changes in land use and the effects of future climate on growth potential as well as on the disturbances regime). Our results suggest that : (1) relatively low growth rate may act as a limiting factor in afforestation projects in which the time available to increase C is driven by natural disturbances; (2) with ongoing climate change, a global increase in natural disturbance rates, mainly fire and spruce budworm outbreaks, may offset any increases in net primary production at the landscape level; (3) the reduction of the albedo versus increase in biomass may negatively affect the net climate forcing; (4) the impermanence of C stock linked to the reversal risks makes this scenario not necessarily cost attractive. More research, notably on the link between fire risk and site productivity, is needed before afforestation can be incorporated into forest management planning to assist climate change mitigation efforts. Therefore, we suggest that conceivable mitigation strategies in the boreal forest will likely have to be directed activities that can reduce emissions and can increase C sinks while minimizing the reversal impacts. Implementation of policies to reduce Greenhouse Gases (GHG) in the boreal forest should consider the biophysical interactions, the different spatial and temporal scales of their benefits, the costs (investment and benefits) and how all these factors are influenced by the site history.     

The influence of the level of definition of functional specifications on the environmental performances of a complex system. EcoCSP approach

The tendency towards a homogenous mode of development modelled on that of Western countries means that sustainable development has become increasingly urgent. It is necessary to thoroughly redefine products and their expected performances in such a way that the consequences are compatible with sustainable development. In the domain of product design, this means that it is no longer sufficient to use assessment tools “after the fact” to check the impact of products whose functional unit (FU) was defined prior to production; it is now necessary to rethink the definition of the FU itself. This article aims to present an approach based on a combination of life cycle analysis methods and problem-solving by constraint satisfaction. This original approach makes it possible to vary the design of the different dimensions of the FUs of a complex system and thus to make it easier to identify the best architecture along with the best functional definition of the system. In this study, the EcoCSP approach is applied to define the functional performances of an ecological passenger ferry. The complexity of couplings between subsystems and the sheer number of those subsystems mean that the designer has to use “intelligent” tools. These simulate a great number of scenarios and help him/her to fine-tune the system and make the right technological choices with regard to the right functional specifications.     

Organochlorine and heavy metals in newborns: Results from the Flemish Environment and Health Survey (FLEHS 2002–2006)

To collect regional information on internal levels of pollutants in humans in Flanders, 1196 mother–child pairs were systematically recruited in 2002–2003 via 25 maternities across Flanders. Cd, Pb, PCB congeners 118, 170, 138, 153 and 180, p,p′-DDE — a key metabolite of DDT- and hexachlorobenzene (HCB) were measured in cord blood or plasma. Cd was detected in 64% of the samples (geometric mean 0.21 µg/L cord blood). p,p′-DDE (110 ng/g plasma lipids) and Pb (14.7 µg/L blood), were measurable in nearly all samples. The individual PCB congeners could be detected in 40 to 81% of the newborns (138 + 153 + 180 = 64.4 ng/g plasma lipids). HCB (18.9 ng/g plasma lipids) and dioxin-like compounds measured by DR-CALUX® (23 pg CALUX-TEQ/g lipids) were above detection limit in more than 75% of the samples. Age and smoking habits of the mothers, did not influence the cord blood Pb and Cd levels. The organochlorines increased 4 to 9% per year of the mother's age (partial R² = 0.05 to 0.22). Mothers had 2.6% less PCBs in cord blood (partial R² = 0.02) for each unit increase in pre-pregnancy BMI. Season of delivery, breastfeeding previous children or consumption of local dairy products, were minor determinants. Up to 20% of the variability in organochlorine concentrations was explained by residence area. It was concluded that the place of birth in Flanders is an important determinant of the load of pollutants measured at the start of life. This underlines the validity of human biomonitoring on (relatively) small geographical scale.     

Aerosol formation yields from the reaction of catechol with ozone

The formation of secondary organic aerosol from the gas-phase reaction of catechol (1,2-dihydroxybenzene) with ozone has been studied in two smog chambers. Aerosol production was monitored using a scanning mobility particle sizer and loss of the precursor was determined by gas chromatography and infrared spectroscopy, whilst ozone concentrations were measured using a UV photometric analyzer. The overall organic aerosol yield (Y) was determined as the ratio of the suspended aerosol mass corrected for wall losses (M_o) to the total reacted catechol concentrations, assuming a particle density of 1.4 g cm^?3. Analysis of the data clearly shows that Y is a strong function of M_o and that secondary organic aerosol formation can be expressed by a one-product gas–particle partitioning absorption model. The aerosol formation is affected by the initial catechol concentration, which leads to aerosol yields ranging from 17% to 86%. The results of this work are compared to similar studies reported in the literature.     

Methane generation in tropical landfills: simplified methods and field results

This paper deals with the use of simplified methods to predict methane generation in tropical landfills. Methane recovery data obtained on site as part of a research program being carried out at the Metropolitan Landfill, Salvador, Brazil, is analyzed and used to obtain field methane generation over time. Laboratory data from MSW samples of different ages are presented and discussed; and simplified procedures to estimate the methane generation potential, Lo, and the constant related to the biodegradation rate, k are applied. The first order decay method is used to fit field and laboratory results. It is demonstrated that despite the assumptions and the simplicity of the adopted laboratory procedures, the values Lo and k obtained are very close to those measured in the field, thus making this kind of analysis very attractive for first approach purposes.     

Impact of training programs on decision-making and situation awareness of trainee watch officers

This paper examines the impact of training programs on the ability of trainee watch officers to make decisions in collision avoidance situations.It draws on previous studies which have shown that experts are able to manage complex situations in an acceptable way. However, observations of students on simulators have revealed that many of them are unable to manage such situations or even to recall their main features. It is therefore necessary to identify new training tools that will give trainees the capacity to assess a situation quickly and accurately, and to perform satisfactory actions. These would be in addition to formal regulations.Exercises were designed to evaluate the impact of such tools on the decision-making process of trainees. The impact of the type of navigation experienced by trainees during their on-the-job training was also evaluated.Results showed that decision-making exercises did tend to improve the trainees’ capacity to analyse a complex situation; however, they did not have a clear impact on the manoeuvre performed. On the contrary, there was an obvious difference between the trainees who experienced complex avoidance situations during their on-the-job training period and those who did not.At a time where ship-owners are looking to reduce the length of the “on-the-job” training period, these results point to its vital importance.     

Carbon Monoxide Concentration in a Street Canyon of Buenos Aires City (Argentina)

The analysis of three years of 8-h CO concentration values registered in a deep street canyon downtown shows high frequency of values that exceed WHO health protection guidelines. An inverse relationship between opposing percentiles of the distributions of CO concentrations and mean wind speed could be found. Data also showed a variation of mean CO values with prevailing wind direction. The averaged concentration value obtained when the sampler probe is on the leeward side is lower than the obtained when it is on the windward wall. A preliminary explanation of this feature may be related to the advection of polluted air from a high traffic density area nearby.     

Influence of Building Density and Roof Shape on the Wind and Dispersion Characteristics in an Urban Area: A Numerical Study

The Computational Fluid Dynamics code CFX-TASCflow is used for simulating the wind flow and pollutant concentration patterns in two-dimensional wind-tunnel models of an urban area. Several two-dimensional multiple street canyon configurations are studied corresponding to different areal densities and roof shapes. A line source of a tracer gas is placed at the bottom of one street canyon for modelling street-level traffic emissions. The flow fields resulting from the simulations correspond to the patterns observed in street canyons. In particular and in good agreement with observations, a dual vortex system is predicted for a deep flat-roof street canyon configuration, while an even more complex vortex system is evidenced in the case of slanted-roof square street canyons. In agreement with measurement data, high pollutant concentration levels are predicted either on the leeward or the windward side of the street canyon, depending on the geometrical details of the surrounding buildings.