Extending genome-wide association study (GWAS) results to test classic anthropological hypotheses: Human third molar agenesis and the ‘probable mutation effect’

A genome-wide association study (GWAS) identifies regions of the genome that likely affect the variable state of a phenotype of interest. These regions can then be studied with population genetic methods to make inferences about the evolutionary history of the trait. There are increasing opportunities to use GWAS results – even from clinically-motivated studies – for tests of classic anthropological hypotheses. One such example, presented here as a case study for this approach, involves tooth development variation related to dental crowding. Specifically, more than 10% of humans fail to develop one or more permanent third molars (M3 agenesis). M3 presence/absence variation within human populations has a significant genetic component (heritability estimate h2 = 0.47). The evolutionary significance of M3 agenesis has a long history of anthropological speculation. First, the modern frequency of M3 agenesis could reflect a relaxation of selection pressure to retain larger and more teeth following the origins of cooking and other food-softening behaviors (i.e., the genetic drift hypothesis, or classically, the “probable mutation effect”). Alternatively, commensurate with increasing hominin brain size and facial shortening, M3 agenesis may have conferred an adaptive fitness advantage if the risk of M3 impaction and potential health complications was reduced (i.e., the positive selection hypothesis). A recent GWAS identified 70 genetic loci that may play a role in human M3 presence/absence variation. To begin evaluating the contrasting evolutionary scenarios for M3 agenesis, we used the integrated haplotype score (iHS) statistic to test whether those 70 genetic regions are enriched for genomic signatures of recent positive selection. None of our findings are inconsistent with the null hypothesis of genetic drift to explain the high prevalence of human M3 agenesis. This result might suggest that M3 impaction rates for modern humans don’t accurately retrodict those of the pre-agricultural past. Alternatively, the absence of support for the positive selection hypothesis could reflect a lack of power; this analysis should be repeated following the completion of more comprehensive GWAS analyses for human M3 agenesis

Greenhouse gas emissions from laboratory-scale fires in wildland fuels depend on fire spread mode and phase of combustion

© Author(s) 2015. Free-burning experimental fires were conducted in a wind tunnel to explore the role of ignition type and thus fire spread mode on the resulting emissions profile from combustion of fine (2, CH4 and N2O) and CO were quantified using off-axis integrated-cavity-output spectroscopy. Emissions factors calculated using a carbon mass balance technique (along with statistical testing) showed that most of the carbon was emitted as CO2, with heading fires emitting 17% more CO2 than flanking and 9.5% more CO2 than backing fires, and about twice as much CO as flanking and backing fires. Heading fires had less than half as much carbon remaining in combustion residues. Statistically significant differences in CH4 and N2O emissions factors were not found with respect to fire spread mode. Emissions factors calculated per unit of dry fuel consumed showed that combustion phase (i.e. flaming or smouldering) had a statistically significant impact, with CO and N2O emissions increasing during smouldering combustion and CO2 emissions decreasing. Findings on the equivalence of different emissions factor reporting methods are discussed along with the impact of our results for emissions accounting and potential sampling biases associated with our work. The primary implication of this study is that prescribed fire practices could be modified to mitigate greenhouse gas emissions from forests by judicial use of ignition methods to induce flanking and backing fires over heading fires

Incorrect interpretation of carbon mass balance biases global vegetation fire emission estimates

© 2016, Nature Publishing Group. All rights reserved. Vegetation fires are a complex phenomenon in the Earth system with many global impacts, including influences on global climate. Estimating carbon emissions from vegetation fires relies on a carbon mass balance technique that has evolved with two different interpretations. Databases of global vegetation fire emissions use an approach based on 'consumed biomass', which is an approximation to the biogeochemically correct 'burnt carbon' approach. Here we show that applying the 'consumed biomass' approach to global emissions from vegetation fires leads to annual overestimates of carbon emitted to the atmosphere by 4.0% or 100 Tg compared with the 'burnt carbon' approach. The required correction is significant and represents ∼9% of the net global forest carbon sink estimated annually. Vegetation fire emission studies should use the 'burnt carbon' approach to quantify and understand the role of this burnt carbon, which is not emitted to the atmosphere, as a sink enriched in carbon

Exploring the properties of pyrogenic carbon with solid state ¹³C nuclear magnetic resonant spectroscopy: A combustion wind tunnel study

© Asia-Pacific Conference on Combustion, ASPACC 2019.All right reserved. Increasing the production of aryl carbon from wildland fire may be beneficial since it can be stored in soils for long periods of time rather than being emitted to the atmosphere or stored in soils in a less recalcitrant form. In this study, solid state 13C nuclear magnetic resonant spectroscopy is used to explore the properties of pyrogenic carbon produced by fires burning with different fire spread modes. Forest litter fuels were burnt using in a combustion wind tunnel using a replicated experimental design. Experiments were performed with three different fire spread modes, involving heading fires that spread with the wind, backing fires that spread against the wind and flanking fires that spread perpendicular to the wind. Results show that heading fires produce significantly more aryl carbon than flanking fires. Analysis of the results with principal component analysis show that maximising the residence time of high temperature combustion and the combustion factor could be an effective method for increasing the production of aryl carbon from fire

Haplobanking induced pluripotent stem cells for clinical use

The development of induced pluripotent stem cells (iPSCs) by Shinya Yamanaka and colleagues in 2006 has led to a potential new paradigm in cellular therapeutics, including the possibility of producing patient-specific, disease-specific and immune matched allogeneic cell therapies. One can envisage two routes to immunologically compatible iPSC therapies: using genetic modification to generate a ‘universal donor’ with reduced expression of Human Leukocyte Antigens (HLA) and other immunological targets or developing a haplobank containing iPSC lines specifically selected to provide HLA matched products to large portions of the population. HLA matched lines can be stored in a designated physical or virtual global bank termed a ‘haplobank’. The process of ‘iPSC haplobanking’ refers to the banking of iPSC cell lines, selected to be homozygous for different HLA haplotypes, from which therapeutic products can be derived and matched immunologically to patient populations. By matching iPSC and derived products to a patient’s HLA class I and II molecules, one would hope to significantly reduce the risk of immune rejection and the use of immunosuppressive medication. Immunosuppressive drugs are used in several conditions (including autoimmune disease and in transplantation procedures) to reduce rejection of infused cells, or transplanted tissue and organs, due to major and minor histocompatibility differences between donor and recipient. Such regimens can lead to immune compromise and pathological consequences such as opportunistic infections or malignancies due to decreased cancer immune surveillance. In this article, we will discuss what is practically involved if one is developing and executing an iPSC haplobanking strategy

Conservation of the Mount Cameron West engraving site

A study of the site and its surroundings indicates that the geochemical environment is such that although the aeolian calcarenite on which the engravings are executed is soft and friable, it is not undergoing appreciable chemical or physical weathering, at least in the short-term. In contrast the site is under considerable threat from coastal erosion. This threat could be reduced, if not eliminated, through the implementation of coastal erosion control measures

Objective Evaluation of Proliferative Diabetic Retinopathy Using OCT

PURPOSE: To present the routine use of OCT and OCT angiography (OCTA) for the objective diagnosis and monitoring of proliferative diabetic retinopathy (PDR). DESIGN: Retrospective, observational case series. PARTICIPANTS: Patients with diabetic retinopathy imaged using a standardized PDR protocol. METHODS: Patients routinely imaged with a standardized PDR protocol between March 2017 and January 2019 were included. This included a 12×9-mm structural OCT volume centered on the macula and a 6×6-mm OCTA scan centered on the optic nerve head obtained using a Topcon swept-source system (DRI OCT-1 Triton, Topcon, Tokyo, Japan). Ultra-widefield fluorescein angiography (FA) was also performed when clinically indicated. The ground truth for each case was determined by merging the findings from biomicroscopy and imaging modalities to generate the maximum level of detection for each finding. MAIN OUTCOME MEASURES: Detection rates of new-onset, regression, and reactivation of neovascularization of the disc (NVD) and neovascularization elsewhere (NVE) using different modalities (biomicroscopy/color photography, structural OCT, B-scan OCTA, en face OCTA). Detection of progression of tractional retinal detachment (TRD). RESULTS: A total of 383 eyes of 204 patients were evaluated. After excluding patients without PDR or with insufficient image quality, 47 eyes of 35 patients were included. For the detection of new-onset NVD and NVE, structural OCT had the highest detection rate (100%) of all modalities. However, for the detection of regression or reactivation of neovascularization (NV), B-scan OCTA had the highest detection rate (100%). Structural OCT detected regression only in 45.5% of cases, resulting in a low detection rate of reactivation (12.5%). Among 10 eyes with TRD, OCT detected fovea-threatening TRD during follow-up in 7 eyes, resulting in vitrectomy. CONCLUSIONS: This study demonstrates the utility of novel multimodal imaging in the daily management of patients with PDR. Posterior pole structural OCT had the best detection rate for NV, and B-scan OCTA showed the most potential for objective monitoring of disease after treatment

The Interpersonal Style and Complementarity Between Crisis Negotiators and Forensic Inpatients

Previous negotiation research has explored the interaction and communication between crisis negotiators and perpetrators. A crisis negotiator attempts to resolve a critical incident through negotiation with an individual, or group of persons in crisis. The purpose of this study was to establish the interpersonal style of crisis negotiators and complementarity of the interpersonal interaction between them and forensic inpatients. Crisis negotiators, clinical workers and students (n = 90) used the Check List of Interpersonal Transactions-Revised (CLOIT-R) to identify interpersonal style, along with eight vignettes detailing interpersonal styles. Crisis negotiators were most likely to have a friendly interpersonal style compared to the other non-trained groups. Complementarity theory was not exclusively supported as submissive individuals did not show optimistic judgments in working with dominant forensic inpatients and vice versa. Exploratory analysis revealed that dominant crisis negotiators were optimistic in working with forensic inpatients with a dominant interpersonal style. This study provides insight into the area of interpersonal complementarity of crisis negotiators and forensic inpatients. Whilst further research is required, a potential new finding was established, with significant ‘similarity’ found when dominant crisis negotiators are asked to work with dominant forensic inpatients

Catastrophizing mediates the relationship between the personal belief in a just world and pain outcomes among chronic pain support group attendees

Health-related research suggests the belief in a just world can act as a personal resource that protects against the adverse effects of pain and illness. However, currently, little is known about how this belief, particularly in relation to one’s own life, might influence pain. Consistent with the suggestions of previous research, the present study undertook a secondary data analysis to investigate pain catastrophizing as a mediator of the relationship between the personal just world belief and chronic pain outcomes in a sample of chronic pain support group attendees. Partially supporting the hypotheses, catastrophizing was negatively correlated with the personal just world belief and mediated the relationship between this belief and pain and disability, but not distress. Suggestions for future research and intervention development are made