A Born-Oppenheimer photolysis model of N_2O fractionation

The isotopically light N_2O produced by microbial activity is thought to be balanced by the return of heavy stratospheric nitrous oxide. The Yung and Miller [1997] method that first explained these trends yields photolytic fractionation factors ∼half those observed by experiment or predicted quantum mechanically, however. To address these issues, we present here a Born-Oppenheimer photolysis model that uses only commonly available spectroscopic data. The predicted fractionations quantitatively reproduce laboratory data, and have been incorporated into zonally averaged atmospheric simulations. Like McLinden et al. [2003] , who employ a three-dimensional chemical transport model with cross sections scaled to match laboratory data, we find excellent agreement between predictions and stratospheric measurements; additional processes that contribute to the mass independent anomaly in N_2O can only account for a fraction of its global budget

A Long View of Polluting Industry and Environmental Justice in Baltimore

Purpose This study examines the density of polluting industry by neighborhoods in Baltimore over the long term, from 1950 to 2010, to determine if high pollution burdens correspond spatially with expected demographic and housing variables predicted in the environmental justice literature. For 1960–1980 we use data on heavy industry from Dun and Bradstreet directories and for 1990–2010 the US EPA’s Toxics Release Inventory to calculate a Hazards Density Index. Drawing on the decennial censuses for 1960–2010, we populate census tracts from corresponding years with data on race, ethnicity, educational attainment, income, and housing tenure. Findings Density of polluting industry is positively correlated with low-income neighborhoods and renter-occupied housing in 1960 and by 2010 with white, Hispanic, and low educational attainment populations. In general, over time density of polluting facilities shifts from an association with wealth to race and ethnicity while educational attainment remains a significant variable throughout. This study confirms earlier analyses on Baltimore that white neighborhoods are more likely than African–American neighborhoods (1990–2010) to contain polluting facilities but reveals for the first time that educational attainment is also significant. The paper concludes with a discussion of the Baltimore Sustainability Plan and its weak efforts to address persistent environmental injustices

Wood heater smoke and mortality in the Australian Capital Territory:a rapid health impact assessment

Objectives: To estimate the number of deaths and the cost of deaths attributable to wood heater smoke in the Australian Capital Territory. Study design: Rapid health impact assessment, based on fine particulate matter (PM2.5) data from three outdoor air pollution monitors and published exposure–response functions for natural cause mortality attributed to PM2.5 exposure. Setting: Australian Capital Territory (population, 2021: 454 000), 2016–2018, 2021, and 2022 (2019 and 2020 excluded because of the impact of extreme bushfires on air quality). Main outcome measures: Proportion of PM2.5 exposure attributable to wood heaters; numbers of deaths and associated cost of deaths (based on the value of statistical life: $5.3 million) attributable to wood heater smoke. Results: Wood heater emissions contributed an estimated 1.16–1.73 μg/m3 to the annual mean PM2.5 concentration during the three colder years (2017, 2018, 2021), or 17–25$57–136 million (most conservative exposure–response function) and $140–333 million (least conservative exposure–response function). Conclusions: The estimated annual number of deaths in the ACT attributable to wood heater PM2.5 pollution is similar to that attributed to the extreme smoke of the 2019–20 Black Summer bushfires. The number of wood heaters should be reduced by banning new installations and phasing out existing units in urban and suburban areas.</p

Dust Grain-Size Distributions From MRN to MEM

Employing the Maximum Entropy Method algorithm, we fit interstellar extinction measurements which span the wavelength range 0.125-3 micron. We present a uniform set of MEM model fits, all using the same grain materials, optical constants and abundance constraints. In addition, we are taking advantage of improved UV and IR data and better estimates of the gas-to-dust ratio. The model fits cover the entire range of extinction properties that have been seen in the Galaxy and the Magellanic Clouds. The grain models employed for this presentation are the simplistic homogeneous spheres models (i.e., Mathis, Rumpl, & Nordsieck 1977) with two (graphite, silicate) or three (graphite, silicate, amorphous carbon) components. Though such usage is only a first step, the results do provide interesting insight into the use of grain size as a diagnostic of dust environment. We find that the SMC Bar extinction curve cannot be fit using carbon grains alone. This is a challenge to the recent observational result indicating little silicon depletion in the SMC.Comment: 24 pages, 5 figures, accepted for publication in the Astrophysical Journa

Assembling highly repetitive Xanthomonas TALomes using Oxford Nanopore sequencing

Background: Most plant-pathogenic Xanthomonas bacteria harbor transcription activator-like effector (TALE) genes, which function as transcriptional activators of host plant genes and support infection. The entire repertoire of up to 29 TALE genes of a Xanthomonas strain is also referred to as TALome. The DNA-binding domain of TALEs is comprised of highly conserved repeats and TALE genes often occur in gene clusters, which precludes the assembly of TALE-carrying Xanthomonas genomes based on standard sequencing approaches. Results: Here, we report the successful assembly of the 5 Mbp genomes of five Xanthomonas strains from Oxford Nanopore Technologies (ONT) sequencing data. For one of these strains, Xanthomonas oryzae pv. oryzae (Xoo) PXO35, we illustrate why Illumina short reads and longer PacBio reads are insufficient to fully resolve the genome. While ONT reads are perfectly suited to yield highly contiguous genomes, they suffer from a specific error profile within homopolymers. To still yield complete and correct TALomes from ONT assemblies, we present a computational correction pipeline specifically tailored to TALE genes, which yields at least comparable accuracy as Illumina-based polishing. We further systematically assess the ONT-based pipeline for its multiplexing capacity and find that, combined with computational correction, the complete TALome of Xoo PXO35 could have been reconstructed from less than 20,000 ONT reads. Conclusions: Our results indicate that multiplexed ONT sequencing combined with a computational correction of TALE genes constitutes a highly capable tool for characterizing the TALomes of huge collections of Xanthomonas strains in the future

Preparedness for practice of newly qualified dental practitioners in the Australian context:an exploratory study

BACKGROUND: The current study explored the perspectives of preparedness for dental practice from a range of relevant stakeholders (i.e., educators, employers, final-year students, graduates, practitioners, and professional associations) using an anonymous online survey in which participants described either their preparedness for practice, or the preparedness of graduates they have encountered, across six domains. RESULTS: A total of 120 participants completed the survey. Participants were from several Australian states and territories; regional, rural, and urban locations; and working in the public and private sector. Students and new graduates generally felt prepared for activities in all the identified domains. Stakeholders reported consistently that the knowledge of dental profession graduates was at the required level to enter practice in Australia in a safe way. Activities involving the knowledge of clinical entrepreneurship and financial solvency were the dimensions where students and graduates felt least prepared (e.g., explaining fees, negotiating finances). In the domains involving clinical and technical competencies, students and new graduates self-assessed as less prepared around managing dental trauma and medical emergencies. On the other hand, activities around social and community orientation, and to a lesser extent professional attitudes and ethical judgements, were the dimensions where students and graduates felt the most prepared. CONCLUSIONS: Present findings indicate that there appear to be good standards of preparedness for practice for graduate dental professionals. This exploratory study provides insights into the nature of preparedness for Australian dental professionals and provides a basis for targeting education and professional development to address areas of need

Exposure to Stress and Air Pollution from Bushfires during Pregnancy: Could Epigenetic Changes Explain Effects on the Offspring?

Due to climate change, bushfires are becoming a more frequent and more severe phenomenon which contributes to poor health effects associated with air pollution. In pregnancy, environmental exposures can have lifelong consequences for the fetus, but little is known about these consequences in the context of bushfire smoke exposure. In this review we summarise the current knowledge in this area, and propose a potential mechanism linking bushfire smoke exposure in utero to poor perinatal and respiratory outcomes in the offspring. Bushfire smoke exposure is associated with poor pregnancy outcomes including reduced birth weight and an increased risk of prematurity. Some publications have outlined the adverse health effects on young children, particularly in relation to emergency department presentations and hospital admissions for respiratory problems, but there are no studies in children who were exposed to bushfire smoke in utero. Prenatal stress is likely to occur as a result of catastrophic bushfire events, and stress is known to be associated with poor perinatal and respiratory outcomes. Changes to DNA methylation are potential epigenetic mechanisms linking both smoke particulate exposure and prenatal stress to poor childhood respiratory health outcomes. More research is needed in large pregnancy cohorts exposed to bushfire events to explore this further, and to design appropriate mitigation interventions, in this area of global public health importance.Vanessa Murphy is supported by an Investigator Grant from the Medical Research Future Fund (grant ID 1196252)

Community based service providers' perspectives on frequent and/or avoidable admission of older people with chronic disease in rural NSW: a qualitative study

Background: Frequent and potentially avoidable hospital admission amongst older patients with ambulatory care sensitive (ACS) chronic conditions is a major topic for research internationally, driven by the imperative to understand and therefore reduce hospital admissions. Research to date has mostly focused on analysis of routine data using ACS as a proxy for 'potentially avoidable'. There has been less research on the antecedents of frequent and/or avoidable admission from the perspectives of patients or those offering community based care and support for these patients. This study aimed to explore community based service providers' perspectives on the factors contributing to admission among older patients with chronic disease and a history of frequent and potentially avoidable admission. Methods. 15 semi-structured interviews with community based providers of health care and other services, and an emergency department physician were conducted. Summary documents were produced and thematic analysis undertaken. Results: A range of complex barriers which limit or inhibit access to services were reported. We classified these as external and internal barriers. Important external barriers included: complexity of provision of services, patients' limited awareness of different services and their inexperience in accessing services, patients needing a higher level or longer length of service than they currently have access to, or an actual lack of available services, patient poverty, rurality, and transport. Important internal barriers included: fear (of change for example), a 'stoic' attitude to life, and for some, the difficulty of accepting their changed health status. Conclusions: The factors underlying frequent and/or potentially avoidable admission are numerous and complex. Identifying strategies to improve services or interventions for this group requires understanding patient, carer and service providers' perspectives. Improving accessibility of services is also complex, and includes consideration of patients' social, emotional and psychological ability and willingness to use services as well as those services being available and easily accessed

All-cause mortality and long-term exposure to low level air pollution in the ‘45 and up study’ cohort, Sydney, Australia, 2006–2015

Epidemiological studies show that long-term exposure to ambient air pollution reduces life expectancy. Most studies have been in environments with relatively high concentrations such as North America, Europe and Asia. Associations at the lower end of the concentration-response function are not well defined.We assessed associations between all-cause mortality and exposure to annual average particulate matte