Development of an Integrated Platform to Assess the Physicochemical and Toxicological Properties of Wood Combustion Particulate Matter

Wood burning contributes to indoor and ambient particulate matter (PM) pollution and has been associated with increased morbidity and mortality. Here, we present an integrated methodology that allows to generate, sample, and characterize wood smoke derived from different moisture contents and representative combustion conditions using pine wood as a model. Flaming, smoldering, and incomplete combustion were assessed for low-moisture pine, whereas both low-moisture pine and high-moisture pine were investigated under flaming conditions. Real-time monitoring of carbon monoxide, volatile organic compounds, and aerosol number concentration/size in wood smoke was performed. The PM was size-fractionated, sampled, and characterized for elemental/organic carbon, organic functional groups, and inorganic elements. Bioactivity of PM was assessed by measuring the sterile alpha motif (SAM) pointed domain containing ETS (E-twenty-six) transcription factor (SPDEF) gene promoter activity in human embryonic kidney 293 (HEK-293T) cells, a biomarker for mucin gene expression. Findings showed that moisture content and combustion condition significantly affected the organic and inorganic elemental composition of PM0.1 as well as its bioactivity. Also, for a given moisture and combustion scenario, PM chemistry and bioactivity differed considerably with PM size. Importantly, PM0.1 from flaming combustion of low-moisture pine contained the highest abundance of the oxygenated saturated aliphatic functional group [H-C-O] and was also biologically most potent in stimulating SPDEF promoter activity, suggesting the role of organic compounds such as carbohydrates and sugar alcohols (that contain [H-C-O]) in driving mucus-related respiratory outcomes. Our platform enables further well-controlled parametric studies using a combination of in vitro and in vivo approaches to link wood burning parameters with acute and chronic inhalation health effects of wood smoke.

Effect of moisture content and fuel type on emissions from vegetation using a steady state combustion apparatus

Emission measurements are available in the literature for a wide variety of field burns and laboratory experiments, although previous studies do not always isolate the effect of individual features such as fuel moisture content (FMC). This study explores the effect of FMC on gaseous and particulate emissions from flaming and smouldering combustion of four different wildland fuels found across the United States. A custom linear tube-heater apparatus was built to steadily produce emissions in different combustion modes over a wide range of FMC. Results showed that when compared with flaming combustion, smouldering combustion showed increased emissions of CO, particulate matter and unburned hydrocarbons, corroborating trends in the literature. CO and particulate matter emissions in the flaming mode were also significantly correlated with FMC, which had little influence on emissions for smouldering mode combustion, when taking into account the dry mass of fuel burned. These variations occurred for some vegetative fuel species but not others, indicating that the type of fuel plays an important role. This may be due to the chemical makeup of moist and recently live fuels, which is discussed and compared with previous measurements in the literature.

Trolls Without Borders: A Cross-Cultural Examination of Victim Reactions to Verbal and Silent Aggression Online

Trolling-the online exploitation of website, chat, or game mechanics at another user's expense-can and does take place all over cyberspace. It can take myriad forms, as well-some verbal, like trash-talking an opponent in a game, and some silent, like refusing to include a new player in a team effort during an in-game quest. However, despite this variety, there are few to no studies comparing the effects of these differing trolling types on victims. In addition, no study has yet taken into account users' offline cultural context and norms into the trolling victim experience. To fill this gap in the literature, the present study put participants from three culturally-distinct countries-Pakistan, Taiwan, and the Netherlands-in a simulated trolling interaction using the Cyberball game. Participants were either flamed (read: harshly insulted) or ostracized by a member of their own cultural group (ingroup) or a minority member (outgroup), and the participants' emotional responses, behavioral intentions toward the other players, and messages sent during the game were taken as indicators of their response to the trolling. Results showed that our Taiwanese sample used the most reactive aggression when trolled and our Dutch sample was the most passive. In addition, ostracism generally produced the desire to repair relationships, irrespective of cultural context, and perpetrator culture (ingroup or outgroup) only produced an effect in the behavioral intentions of our Pakistani sample. Overall, it would appear that online and offline culture interact to produce the variety of responses to trolling seen in extant literature. Additional implications for future research into computer-mediated communication and online aggression are also discussed.

Optimising seed processing techniques to improve germination and sowability of native grasses for ecological restoration

Grasslands across the globe are undergoing expansive degradation due to human impacts and climate change. If restoration of degraded native grassland is to be achieved at the scale now required, cost-effective means for seed-based establishment of grass species is crucial. However, grass seeds present numerous challenges associated with handling and germination performance that must be overcome to improve the efficiency of seeding. Previous research has demonstrated that complete removal of the palea and lemma (husk) maximises germination performance, hence we investigated the effects of complete husk removal on seed handling and germination of four temperate Australian grass species. Three techniques were tested to remove the husk - manual cleaning, flaming or acid digestion (the latter two followed by a manual cleaning step); these techniques were refined and adapted to the selected species, and germination responses were compared. The complete removal of the husk improved seed handling and sowability for all species. Germination was improved in Microlaena stipoides by 19% and in Rytidosperma geniculatum by 11%. Of the husk removal methods tested, flaming was detrimental to seed germination and fatal for one species (R. geniculatum). Compared to manual cleaning, sulphuric acid improved the overall efficacy of the cleaning procedure and increased germination speed (T50) in Austrostipa scabra, Chloris truncata and M. stipoides, and improved final germination in R. geniculatum by 13%. The seed processing methods developed and tested in the present study can be applied to grass species that present similar handling and germination performance impediments. These and other technological developments (seed coating and precision sowing) will facilitate more efficient grassland restoration at large scale.

Self-control in Online Discussions: Disinhibited Online Behavior as a Failure to Recognize Social Cues

In an online experiment we examined the role of self-control in recognizing social cues in the context of disinhibited online behavior (e.g., flaming and trolling). We temporarily lowered participants' self-control capacity with an ego depletion paradigm (i.e., color Stroop task). Next, we measured participants' sensitivity to social cues with an emotional Stroop task containing neutral, negative, and taboo words. Sensitivity to social cues is represented by the increase in reaction time to negative and especially taboo words compared to neutral words. As expected, undepleted participants were slower to process the color of negative and taboo words. By contrast, depleted participants (i.e., those with lowered self-control capacity) did not react differently to taboo or negative words than they did to neutral words. The experiment illustrates that self-control failure may manifest itself in a failure to recognize social cues. The finding underlines the importance of self-control in understanding disinhibited online behavior: Many instances of disinhibited online behavior may occur not because people are unable to control themselves, but because they do not realize that a situation calls for self-control in the first place.