The impact of bath gas composition on the calibration of photoacoustic spectrometers with ozone at discrete visible wavelengths spanning the Chappuis band

This is the author accepted manuscript. The final version is available from EGU via the DOI in this record.For data related to this paper, please contact Michael I. Cotterell (or Justin M. LangridgePhotoacoustic spectroscopy is a sensitive in situ technique for measuring the absorption coefficient for gas and aerosol samples. Photoacoustic spectrometer (PAS) instruments require accurate calibration by comparing the measured photoacoustic response with a known level of absorption for a calibrant. Ozone is a common calibrant of PAS instruments, yet recent work by Bluvshtein et al. (2017) has cast uncertainty on the validity of ozone as a calibrant at a wavelength of 405 nm. Moreover, Fischer and Smith (2018) demonstrate that a low O2 mass fraction in the bath gas can bias the measured PAS calibration coefficient to lower values for wavelengths in the range 532–780 nm. In this contribution, we present PAS sensitivity measurements at wavelengths of 405, 514 and 658 nm using ozone-based calibrations with variation in the relative concentrations of O2 and N2 bath gases. We find excellent agreement with the results of Fischer and Smith at the 658 nm wavelength. However, the PAS sensitivity decreases significantly as the bath gas composition tends to pure oxygen for wavelengths of 405 and 514 nm, which cannot be rationalised using arguments presented in previous studies. To address this, we develop a model to describe the variation in PAS sensitivity with both wavelength and bath gas composition that considers Chappuis band photodynamics and recognises that the photoexcitation of O3 leads rapidly to the photodissociation products O(3P) and O2(X, v > 0). We show that the rates of two processes are required to model the PAS sensitivity correctly. The first process involves the formation of vibrationally excited O3(X˜) through the reaction of the nascent O(3P) with bath gas O2. The second process involves the quenching of vibrational energy from the nascent O2(X, v > 0) to translational modes of the bath gas. Both of these processes proceed at different rates in collisions with N2 or O2 bath gas species. Importantly, we show that the PAS sensitivity is optimised for our PAS instruments when the ozone-based calibration is performed in a bath gas with a similar composition to ambient air and conclude that our methods for measuring aerosol absorption using an ozone-calibrated PAS are accurate and without detectable bias. We emphasise that the dependence of PAS sensitivity on bath gas composition is wavelength-dependent, and we recommend strongly that researchers characterise the optimal bath gas composition for their particular instrument.Analytical Chemistry Trust FundResearch Council on Norwa

Radiation effects in glasses used for immobilization of high-level waste and plutonium disposition

This paper is a comprehensive review of the state-of-knowledge in the field of radiation effects in glasses that are to be used for the immobilization of high-level nuclear waste and plutonium disposition. The current status and issues in the area of radiation damage processes, defect generation, microstructure development, theoretical methods and experimental methods ase reviewed. Questions of fundamental and technological interest that offer opportunities for research are identified

Association between Knops blood group polymorphisms and susceptibility to malaria in an endemic area of the Brazilian Amazon

Complement receptor 1 (CR1) gene polymorphisms that are associated with Knops blood group antigens may influence the binding of Plasmodium parasites to erythrocytes, thereby affecting susceptibility to malaria. The aim of this study was to evaluate the genotype and allele and haplotype frequencies of single-nucleotide polymorphisms (SNPs) of Knops blood group antigens and examine their association with susceptibility to malaria in an endemic area of Brazil. One hundred and twenty-six individuals from the Brazilian Amazon were studied. The CR1-genomic fragment was amplified by PCR and six SNPs and haplotypes were identified after DNA sequence analysis. Allele and haplotype frequencies revealed that the Knb allele and H8 haplotype were possibly associated with susceptibility to Plasmodium falciparum. The odds ratios were reasonably high, suggesting a potentially important association between two Knops blood antigens (Knb and KAM+) that confer susceptibility to P. falciparum in individuals from the Brazilian Amazon

Increasing understanding of the relationship between geographic access and gendered decision-making power for treatment-seeking for febrile children in the Chikwawa district of Malawi

Background: This study used qualitative methods to investigate the relationship between geographic access and gendered intra-household hierarchies and how these influence treatment-seeking decision-making for childhood fever within the Chikwawa district of Malawi. Previous cross-sectional survey findings in the district indicated that distance from facility and associated costs are important determinants of health facility attendance in the district. This paper uses qualitative data to add depth of understanding to these findings by exploring the relationship between distance from services, anticipated costs and cultural norms of intra-household decision-making, and to identify potential intervention opportunities to reduce challenges experienced by those in remote locations. Qualitative data collection included 12 focus group discussions and 22 critical incident interviews conducted in the local language, with primary caregivers of children who had recently experienced a febrile episode. Results: Low geographic accessibility to facilities inhibited care-seeking, sometimes by extending the ‘assessment period’ for a child’s illness episode, and led to delays in seeking formal treatment, particularly when the illness occurred at night. Although carers attempted to avoid incurring costs, cash was often needed for transport and food. Whilst in all communities fathers were normatively responsible for treatment costs, mothers generally had greater access to and control over resources and autonomy in decision-making in the matrilineal and matrilocal communities in the central part of the district, which were also closer to formal facilities. Conclusions: This study illustrates the complex interplay between geographic access and gender dynamics in shaping decisions on whether and when formal treatment is sought for febrile children in Chikwawa District. Geographic marginality and cultural norms intersect in remote areas both to increase the logistical and anticipated financial barriers to utilising services and to reduce caretakers’ autonomy to act quickly once they recognize the need for formal care. Health education campaigns should be based within communities, engaging all involved in treatment-seeking decision-making, including men and grandmothers, and should aim to promote the ability of junior women to influence the treatment-seeking process. Both mothers’ financial autonomy and fathers financial contributions are important to enable timely access to effective healthcare for children with malaria

Identification of Colletotrichum species associated with anthracnose disease of coffee in Vietnam

Colletotrichum gloeosporioides, C. acutatum, C. capsici and C. boninense associated with anthracnose disease on coffee (Coffea spp.) in Vietnam were identified based on morphology and DNA analysis. Phylogenetic analysis of DNA sequences from the internal transcribed spacer region of nuclear rDNA and a portion of mitochondrial small subunit rRNA were concordant and allowed good separation of the taxa. We found several Colletotrichum isolates of unknown species and their taxonomic position remains unresolved. The majority of Vietnamese isolates belonged to C. gloeosporioides and they grouped together with the coffee berry disease (CBD) fungus, C. kahawae. However, C. kahawae could be distinguished from the Vietnamese C. gloeosporioides isolates based on ammonium tartrate utilization, growth rate and pathogenictity. C. gloeosporioides isolates were more pathogenic on detached green berries than isolates of the other species, i.e. C. acutatum, C capsici and C. boninense. Some of the C. gloeosporioides isolates produced slightly sunken lesion on green berries resembling CBD symptoms but it did not destroy the bean. We did not find any evidence of the presence of C. kahawae in Vietnam

Dynamics of direct inter-pack encounters in endangered African wild dogs

Aggressive encounters may have important life history consequences due to the potential for injury and death, disease transmission, dispersal opportunities or exclusion from key areas of the home range. Despite this, little is known of their detailed dynamics, mainly due to the difficulties of directly observing encounters in detail. Here, we describe detailed spatial dynamics of inter-pack encounters in African wild dogs (Lycaon pictus), using data from custom-built high-resolution GPS collars in 11 free-ranging packs. On average, each pack encountered another pack approximately every 7 weeks and met each neighbour twice each year. Surprisingly, intruders were more likely to win encounters (winning 78.6% of encounters by remaining closer to the site in the short term). However, intruders did tend to move farther than residents toward their own range core in the short-term (1 h) post-encounter, and if this were used to indicate losing an encounter, then the majority (73.3%) of encounters were won by residents. Surprisingly, relative pack size had little effect on encounter outcome, and injuries were rare (<15% of encounters). These results highlight the difficulty of remotely scoring encounters involving mobile participants away from static defendable food resources. Although inter-pack range overlap was reduced following an encounter, encounter outcome did not seem to drive this, as both packs shifted their ranges post-encounter. Our results indicate that inter-pack encounters may be lower risk than previously suggested and do not appear to influence long-term movement and ranging

The psychic costs of migration: evidence from Irish return migrants

Within the economics literature, the 'psychic costs' of migration have been incorporated into theoretical models since Sjaastad (J Polit Econ 70:80 93, 1962). However, the existence of such costs has rarely been investigated in empirical papers. In this paper, we look at the psychic costs of migration by using alcohol problems as an indicator. Rather than comparing immigrants and natives, we look at the native-born in a single country and compare those who have lived away for a period of their lives and those who have not. We use data from the first wave of the Irish Longitudinal Study on Ageing which is a large, nationally representative sample of older Irish adults. We find that men who lived away are more likely to have suffered from alcohol problems than men who stayed. For women, we again see a higher incidence of alcohol problems for short-term migrants. However, long-term female migrants are less likely to have suffered from alcohol problems. For these women, it seems that migration provided psychic benefits, and this is consistent with findings fro

Classification of Plant Associated Bacteria Using RIF, a Computationally Derived DNA Marker

A DNA marker that distinguishes plant associated bacteria at the species level and below was derived by comparing six sequenced genomes of Xanthomonas, a genus that contains many important phytopathogens. This DNA marker comprises a portion of the dnaA replication initiation factor (RIF). Unlike the rRNA genes, dnaA is a single copy gene in the vast majority of sequenced bacterial genomes, and amplification of RIF requires genus-specific primers. In silico analysis revealed that RIF has equal or greater ability to differentiate closely related species of Xanthomonas than the widely used ribosomal intergenic spacer region (ITS). Furthermore, in a set of 263 Xanthomonas, Ralstonia and Clavibacter strains, the RIF marker was directly sequenced in both directions with a success rate approximately 16% higher than that for ITS. RIF frameworks for Xanthomonas, Ralstonia and Clavibacter were constructed using 682 reference strains representing different species, subspecies, pathovars, races, hosts and geographic regions, and contain a total of 109 different RIF sequences. RIF sequences showed subspecific groupings but did not place strains of X. campestris or X. axonopodis into currently named pathovars nor R. solanacearum strains into their respective races, confirming previous conclusions that pathovar and race designations do not necessarily reflect genetic relationships. The RIF marker also was sequenced for 24 reference strains from three genera in the Enterobacteriaceae: Pectobacterium, Pantoea and Dickeya. RIF sequences of 70 previously uncharacterized strains of Ralstonia, Clavibacter, Pectobacterium and Dickeya matched, or were similar to, those of known reference strains, illustrating the utility of the frameworks to classify bacteria below the species level and rapidly match unknown isolates to reference strains. The RIF sequence frameworks are available at the online RIF database, RIFdb, and can be queried for diagnostic purposes with RIF sequences obtained from unknown strains in both chromatogram and FASTA format

Off the Couch and Onto the Streets: Toward an Ethnographic Psychoanalysis

Psychoanalysis has much to gain by incorporating ethnographic methods into its repertoire. Recent works in ethnographic psychoanalysis demonstrate how psychoanalysis stands to function better as both community intervention and participatory action research. This article describes the historical convergence between psychoanalysis and cultural anthropology and situates ethnographic psychoanalysis within interdisciplinary theory and practice