Rich biomass combustion: Gaseous and particle number emissions

The cone calorimeter is a standard test method for material behaviour in fires. The principle of the cone calorimeter is to use an electric radiant heater to raise the temperature of the combustion zone and ignite the fuel. 35 kW/m 2 was used in the present work, as this has been previously shown to be sufficient to establish fully developed combustion of biomass materials such as wood. As one of the main fire loads is wood and wood is the dominant biomass for energy generation, it is reasonable to use the cone calorimeter to characterize the combustion of biomass on a small scale and pine was used in the present work. The cone calorimeter was used in the controlled atmosphere mode with an enclosure around the test biomass that enabled the air flow for biomass combustion to be controlled at 19.2 g/m 2 s, which corresponds to a combustion heat release rate HRR of 57 kW/m 2 , assuming all the oxygen in the air is consumed. This air flow will be shown to generate rich combustion at a metered equivalence ratio, Ø of about 2, which is comparable with the first gasification stage of biomass two stage burning in log burners and pellet burners, where air is added downstream of the gasification stage of biomass combustion. Soot emissions are generated in this rich gasification stage burning and potentially oxidized in the oxidation second stage burning. The rich burning gasification zone particulate emissions were analysed for number size distribution using the Cambustion DMS 500 particle size analyser. The exit from the controlled combustion zone was extended in a 75 mm diameter chimney where a mean gas sample was taken. A heated Gasmet FTIR was used for gas composition analysis, using a heated sample line, filter and pump from the sample point to the analyser. The particles emitted were sampled after the second stage combustion from entrained air into the chimney discharge gases into a dilution tunnel with a fixed gas flow rate of 24 l/s, which gave a dilution ratio of the primary combustion gases of 150/1 which is required for nano-particle size analysis. A Cambustion DMS500 electrical mobility particle number and size instrument was used with size resolution from 5 to 1000 nm. The present results show that in the rich burning first stage chimney sample there were very high levels of 20 nm nanoparticles, 1 × 10 10 /cc, and an accumulation mode peak at 200 nm. The presence of the 20 nm particles makes the particulate emissions extremely toxic

The influence of interactions with students for the development of new academics as teachers in higher education

The aim of the current investigation was to provide an insight into how new lecturers in higher education develop as teachers and to identify some of the main influences upon this development. A qualitative, longitudinal design with three semi-structured interviews over a 2-year period was employed with eleven new teachers from a range of higher education institutions and settings. The analysis used case studies, alongside a thematic analysis, to provide fine-grained and idiosyncratic insights into the teachers’ development. The principal finding from the current study was the identification that instances of interactions with students, acted as a core influence upon the new teachers’ development. These instances appeared to provide the teachers with richer and fuller feedback about their teaching. This feedback supported their reflection and influenced the way in which they thought about teaching. Based on these findings it is suggested that teacher development could be enhanced by focussing upon specific instances of interactions with students as these instances provide specific and tangible moments that allow individuals to reflect upon and discuss their conceptions of teaching

Sustaining modified behaviours learnt in a diabetes prevention program in regional Australia : the role of social context

BackgroundThe Greater Green Triangle diabetes prevention program was conducted in primary health care setting of Victoria and South Australia in 2004--2006. This program demonstrated significant reductions in diabetes risk factors which were largely sustained at 18 month follow-up. The theoretical model utilised in this program achieved its outcomes through improvements in coping self-efficacy and planning. Previous evaluations have concentrated on the behavioural components of the intervention. Other variables external to the main research design may have contributed to the success factors but have yet to be identified. The objective of this evaluation was to identify the extent to which participants in a diabetes prevention program sustained lifestyle changes several years after completing the program and to identify contextual factors that contributed to sustaining changes.MethodsA qualitative evaluation was conducted. Five focus groups were held with people who had completed a diabetes prevention program, several years later to assess the degree to which they had sustained program strategies and to identify contributing factors.ResultsParticipants value the recruitment strategy. Involvement in their own risk assessment was a strong motivator. Learning new skills gave participants a sense of empowerment. Receiving regular pathology reports was a means of self-assessment and a motivator to continue. Strong family and community support contributed to personal motivation and sustained practice.ConclusionsFamily and local community supports constitute the contextual variables reported to contribute to sustained motivation after the program was completed. Behaviour modification programs can incorporate strategies to ensure these factors are recognised and if necessary, strengthened at the local level.<br /

An Integrative Approach to Understanding Counterproductive Work Behavior: The Roles of Stressors, Negative Emotions, and Moral Disengagement

Several scholars have highlighted the importance of examining moral disengagement (MD) in understanding aggression and deviant conduct across different contexts. The present study investigates the role of MD as a specific social-cognitive construct that, in the organizational context, may intervene in the process leading from stressors to counterproductive work behavior (CWB). Assuming the theoretical framework of the stressor-emotion model of CWB, we hypothesized that MD mediates, at least partially, the relation between negative emotions in reaction to perceived stressors and CWB by promoting or justifying aggressive responses to frustrating situations or events. In a sample of 1,147 Italian workers, we tested a structural equations model. The results support our hypothesis: the more workers experienced negative emotions in response to stressors, the more they morally disengaged and, in turn, enacted CW

Carcass persistence and detectability : reducing the uncertainty surrounding wildlife-vehicle collision surveys

Carcass persistence time and detectability are two main sources of uncertainty on roadkill surveys. In this study, we evaluate the influence of these uncertainties on roadkill surveys and estimates. To estimate carcass persistence time, three observers (including the driver) surveyed 114km by car on a monthly basis for two years, searching for wildlife-vehicle collisions (WVC). Each survey consisted of five consecutive days. To estimate carcass detectability, we randomly selected stretches of 500m to be also surveyed on foot by two other observers (total 292 walked stretches, 146 km walked). We expected that body size of the carcass, road type, presence of scavengers and weather conditions to be the main drivers influencing the carcass persistence times, but their relative importance was unknown. We also expected detectability to be highly dependent on body size. Overall, we recorded low median persistence times (one day) and low detectability (<10%) for all vertebrates. The results indicate that body size and landscape cover (as a surrogate of scavengers' presence) are the major drivers of carcass persistence. Detectability was lower for animals with body mass less than 100g when compared to carcass with higher body mass. We estimated that our recorded mortality rates underestimated actual values of mortality by 2±10 fold. Although persistence times were similar to previous studies, the detectability rates here described are very different from previous studies. The results suggest that detectability is the main source of bias across WVC studies. Therefore, more than persistence times, studies should carefully account for differing detectability when comparing WVC studies

Genetic Evaluation of Hip Score in UK Labrador Retrievers

Hip dysplasia is an important and complex genetic disease in dogs with both genetic and environmental influences. Since the osteoarthritis that develops is irreversible the only way to improve welfare, through reducing the prevalence, is through genetic selection. This study aimed to evaluate the progress of selection against hip dysplasia, to quantify potential improvements in the response to selection via use of genetic information and increases in selection intensity, and to prepare for public provision of estimated breeding values (EBV) for hip dysplasia in the UK. Data consisted of 25,243 single records of hip scores of Labrador Retrievers between one and four years old, from radiographs evaluated between 2000 and 2007 as part of the British Veterinary Association (BVA) hip score scheme. A natural logarithm transformation was applied to improve normality and linear mixed models were evaluated using ASREML. Genetic correlations between left and right scores, and total hip scores at one, two and three years of age were found to be close to one, endorsing analysis of total hip score in dogs aged one to three as an appropriate approach. A heritability of 0.35±0.016 and small but significant litter effect (0.07±0.009) were estimated. The observed trends in both mean hip score and mean EBV over year of birth indicate that a small genetic improvement has been taking place, approximately equivalent to avoiding those dogs with the worst 15% of scores. Deterministic analysis supported by simulations showed that a 19% greater response could be achieved using EBV compared to phenotype through increases in accuracy alone. This study establishes that consistent but slow genetic improvement in the hip score of UK Labrador Retrievers has been achieved over the previous decade, and demonstrates that progress may be easily enhanced through the use of EBVs and more intense selection

Coevolution in Action: Disruptive Selection on Egg Colour in an Avian Brood Parasite and Its Host

Trait polymorphism can evolve as a consequence of frequency-dependent selection. Coevolutionary interactions between hosts and parasites may lead to selection on both to evolve extreme phenotypes deviating from the norm, through disruptive selection.Here, we show through detailed field studies and experimental procedures that the ashy-throated parrotbill (Paradoxornis alphonsianus) and its avian brood parasite, the common cuckoo (Cuculus canorus), have both evolved egg polymorphism manifested in discrete immaculate white, pale blue, and blue egg phenotypes within a single population. In this host-parasite system the most common egg colours were white and blue, with no significant difference in parasitism rates between hosts laying eggs of either colour. Furthermore, selection on parasites for countering the evolution of host egg types appears to be strong, since ashy-throated parrotbills have evolved rejection abilities for even partially mimetic eggs.The parrotbill-cuckoo system constitutes a clear outcome of disruptive selection on both host and parasite egg phenotypes driven by coevolution, due to the cost of parasitism in the host and by host defences in the parasite. The present study is to our knowledge the first to report the influence of disruptive selection on evolution of discrete phenotypes in both parasite and host traits in an avian brood parasitism system

Adaptive Evolution of the Venom-Targeted vWF Protein in Opossums that Eat Pitvipers

The rapid evolution of venom toxin genes is often explained as the result of a biochemical arms race between venomous animals and their prey. However, it is not clear that an arms race analogy is appropriate in this context because there is no published evidence for rapid evolution in genes that might confer toxin resistance among routinely envenomed species. Here we report such evidence from an unusual predator-prey relationship between opossums (Marsupialia: Didelphidae) and pitvipers (Serpentes: Crotalinae). In particular, we found high ratios of replacement to silent substitutions in the gene encoding von Willebrand Factor (vWF), a venom-targeted hemostatic blood protein, in a clade of opossums known to eat pitvipers and to be resistant to their hemorrhagic venom. Observed amino-acid substitutions in venom-resistant opossums include changes in net charge and hydrophobicity that are hypothesized to weaken the bond between vWF and one of its toxic snake-venom ligands, the C-type lectin-like protein botrocetin. Our results provide the first example of rapid adaptive evolution in any venom-targeted molecule, and they support the notion that an evolutionary arms race might be driving the rapid evolution of snake venoms. However, in the arms race implied by our results, venomous snakes are prey, and their venom has a correspondingly defensive function in addition to its usual trophic role

Heritability and Phenotypic Variation of Canine Hip Dysplasia Radiographic Traits in a Cohort of Australian German Shepherd Dogs

Canine Hip Dysplasia (CHD) is a common, painful and debilitating orthopaedic disorder of dogs with a partly genetic, multifactorial aetiology. Worldwide, potential breeding dogs are evaluated for CHD using radiographically based screening schemes such as the nine ordinally-scored British Veterinary Association Hip Traits (BVAHTs). The effectiveness of selective breeding based on screening results requires that a significant proportion of the phenotypic variation is caused by the presence of favourable alleles segregating in the population. This proportion, heritability, was measured in a cohort of 13,124 Australian German Shepherd Dogs born between 1976 and 2005, displaying phenotypic variation for BVAHTs, using ordinal, linear and binary mixed models fitted by a Restricted Maximum Likelihood method. Heritability estimates for the nine BVAHTs ranged from 0.14–0.24 (ordinal models), 0.14–0.25 (linear models) and 0.12–0.40 (binary models). Heritability for the summed BVAHT phenotype was 0.30±0.02. The presence of heritable variation demonstrates that selection based on BVAHTs has the potential to improve BVAHT scores in the population. Assuming a genetic correlation between BVAHT scores and CHD-related pain and dysfunction, the welfare of Australian German Shepherds can be improved by continuing to consider BVAHT scores in the selection of breeding dogs, but that as heritability values are only moderate in magnitude the accuracy, and effectiveness, of selection could be improved by the use of Estimated Breeding Values in preference to solely phenotype based selection of breeding animals