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Implying climate impact from carbon prices and consumption
Get PDFThe value of the social cost of carbon (SCC) remains contested, despite having been described as the single most important concept in the economics of climate change. The SCC represents the discounted reduction in welfare caused by the release of an additional tonne of carbon dioxide equivalent (tCO2e) greenhouse gas emissions into the atmosphere. In practice, many estimates of the SCC are not robust or comparable, due to technical issues, including parameter estimation in climate assessment models. Using a market-based approach to calculate climate change metrics can avoid some of the controversy associated with calculating the SCC and subjectivity in deriving temperature alignment from transition plans. This study inverts results from an integrated assessment model commonly used to calculate the optimal SCC. A relationship is inferred between carbon price and both climate damages and implied temperature alignment. Using national data on effective cost of carbon (ECC), i.e. current carbon prices, the global market-implied temperature alignment is 3°C of warming. Using carbon consumption data to calculate implied climate impact, the per capita impact of higher-income countries is significantly higher than in low- and medium-income countries. The findings suggest that globally an ECC above $85/tCO2e may be required for implied temperature alignment to fall below 2°C of warming. However, both higher-income economies and those with high per capita carbon consumption levels may need to set their ECC at twice this level if their climate impact is to fall below a level aligned with limiting warming to 2°C
Survival outcomes in patients with sigmoid volvulus
Get PDFAim This study aimed to assess management pathways and outcomes in sigmoid volvulus (SV). MethodsA retrospective review was performed on patients first admitted with SV between 2019 and 2023 within a tertiary-level colorectal service. Demographic, management, and outcome data, including frailty, ASA (American Society of Anaesthesiologists), and National Emergency Laparotomy Audit (NELA) score, were collected. Comparative statistics were used to compare baseline demographics between those operated on and those not and to identify factors associated with survival.ResultsA total of 72 patients were included, median age of 78 years, with 25 undergoing surgery. After index discharge without surgery, 50 patients (88%) were re-admitted with SV at least once, with a total of 212 hospital admissions and 1952 hospital bed days at the end of follow-up. A trend towards lower age, NELA score, ASA score and frailty score was seen in those undergoing surgery, with only 2 deaths observed during postoperative follow-up. In those who were not palliated at first admission but did not undergo surgery at any point, the mortality rate was 42% (n=16, median survival 545 days, median age 79), with causes of death generally reflecting conditions of frailty and not volvulus itself. ConclusionsThis study demonstrates the burden of sigmoid volvulus in an elderly population with significant mortality and morbidity. Whilst survival was better in those undergoing surgery, this likely represents appropriate case selection reflecting underlying frailty and comorbidities in those not offered surgery rather than a protective effect of surgery. While surgery should be considered and documented at index admission, it should not be considered a panacea for the elderly and frail population. <br/
Inhibiting Infectious Bronchitis Virus PLpro Using Ubiquitin Variants
Get PDFInfectious bronchitis virus (IBV) is a coronavirus first isolated in the 1930s infecting chickens. IBV causes great economic losses to the global poultry industry, as it affects egg production and causes mortality by leaving the host susceptible to secondary bacterial infections. Even though vaccines are available, they are poorly cross-protective against new variants of the virus, which are always on the cusp of emerging. Effective antiviral therapies, or possibly the production of transgenic animals immune to IBV infection, are therefore sorely needed. As the papain-like protease (PLpro) of IBV has deubiquitinating activity besides its crucial ability to cleave the viral polyprotein, we have applied a novel strategy of selecting ubiquitin variants (UbVs) from a phage-displayed library that have high affinity to this viral protease. These UbVs were found to inhibit the deubiquitinating activity of PLpro and consequently obstruct the virus's ability to evade the innate immune response in the host cell. By obstructing the proteolytic activity of PLpro, these UbVs were seemingly able to inhibit viral infection as assessed using immunofluorescence microscopy. Whilst virus infection was detected in around 5% of UbV-expressing cells, the virus was present in around 30-40% of GFP (control)-expressing cells. This suggests that the expression of UbVs indeed seems to inhibit IBV infection, making UbVs a potentially potent and innovative antiviral strategy in the quest for control of IBV infections.</p
Animal colour change proximate mechanisms, evolutionary ecology and response to anthropogenic impacts
Get PDFAnimal colour has multiple functions in nature, from sexual signalling to protecting individuals against visual predators. However, instead of being a fixed trait, colour and patterning may be changed over different time scales according to variable selective pressures. Early research on animal colour change focused on the pigments driving rapid and slow changes in a few animal groups, shedding light on cellular and some physiological mechanisms. Conversely, over the past 20 years of research, advances in colour quantification and increased emphasis on the adaptive function of colour change has prompted investigations within ecological and evolutionary frameworks. These include more recent research on how human impacts, such as pollution and habitat modification, may disrupt colour change by affecting animal physiology or exposing organisms to altered environmental conditions. Here, we comprehensively review what is known regarding the physiological and ecological mechanisms behind dynamic (i.e. reversible) colour change in animals. We begin with an overview of colour change mechanisms, covering classic cellular processes while highlighting new molecular and physiological insights. Next, we discuss the evolutionary ecology of colour change, reviewing evidence of its adaptive value and links to behaviour. Finally, we examine anthropogenic impacts on animal colour change, addressing how factors such as pollution and habitat modification influence colour plasticity. We conclude by identifying key unresolved questions and proposing directions for future research.</p
The Association Between an Individual’s Local Food Environment and Diet Quality among Postpartum Women Living in Rural Bangladesh
Get PDFBACKGROUND: The food environment is a driver of the double burden of malnutrition, influencing dietary intake by increasing or restricting access to foods.OBJECTIVES: The objective of this study was to assess the association between geospatial food environment indicators and the diet quality among postpartum women in rural Bangladesh.METHODS: Participants were women of infants enrolled in a cluster-randomized controlled trial from 2018 to 2020. Food vendor availability was defined as the number of food vendors within a specific household radius, and proximity was defined as the distance to the nearest vendor. Dietary intake was measured using a 7-d food frequency questionnaire collected at 3 mo, 6 mo, and 12 mo postpartum. Our primary outcome was nonstarchy staple food variety scores (FVS). Secondary outcomes included dietary diversity scores and individual food group consumption. To assess the association between food environment indicators and diet quality indicators, we fit linear regression models for the FVS outcome, Poisson regression models for the dietary diversity outcome, and logistic regression models for individual food group outcomes.RESULTS: A total of 5064 women were included in this analysis. Women reported consuming an average of 9.7 (standard deviation: 3.7) nonstarchy staple foods in the previous week. Women who lived in households with the highest market availability (≥7 markets within 1600 m) had an average of 0.84-unit (95% confidence interval: 0.53, 1.16) higher FVS compared with those in households with the lowest market availability (≤ 2 markets) ( P < 0.001). Geospatial food environment indicators were not significantly associated with the odds of consuming less healthy food options. CONCLUSIONS: We found a positive relationship between market availability and diet quality for postpartum women in rural Bangladesh. However, more research is needed to understand which components of the food environment are associated with increased consumption of less healthy foods.</p
Entropy Annealing for Policy Mirror Descent in Continuous Time and Space
Get PDFEntropy regularization has been widely used in policy optimization algorithms to enhance exploration and the robustness of the optimal control; however it also introduces an additional regularization bias. This work quantifies the impact of entropy regularization on the convergence of policy gradient methods for stochastic exit time control problems. We analyze a continuous-time policy mirror descent dynamics, which updates the policy based on the gradient of an entropy-regularized value function and adjusts the strength of entropy regularization as the algorithm progresses. We prove that with a fixed entropy level, the mirror descent dynamics converges exponentially to the optimal solution of the regularized problem. We further show that when the entropy level decays at suitable polynomial rates, the annealed flow converges to the solution of the unregularized problem at a rate of for discrete action spaces and, under suitable conditions, at a rate of for general action spaces, with being the gradient flow running time. The technical challenge lies in analyzing the gradient flow in the infinite-dimensional space of Markov kernels for nonconvex objectives. This paper explains how entropy regularization improves policy optimization, even with the true gradient, from the perspective of convergence rate
Modeling Porosity Distribution Strategies in PEM Water Electrolyzers: A Comparative Analytical and Numerical Study
Get PDFProton exchange membrane water electrolyzers (PEMWEs) are a promising technology for green hydrogen production. However, the adoption of PEMWE-based hydrogen production systems remains limited due to several challenges, including high material costs, limited performance and durability, and difficulties in scaling the technology. Computational modeling serves as a powerful tool to address these challenges by optimizing system design, improving material performance, and reducing overall costs, thereby accelerating the commercial rollout of PEMWE technology. Despite this, conventional models often oversimplify key components, such as porous transport and catalyst layers, by assuming constant porosity and neglecting the spatial heterogeneity found in real electrodes. This simplification can significantly impact the accuracy of performance predictions and the overall efficiency of electrolyzers. This study develops a mathematical framework for modeling variable porosity distributions—including constant, linearly graded, and stepwise profiles—and derives analytical expressions for permeability, effective diffusivity, and electrical conductivity. These functions are integrated into a three-dimensional multi-domain COMSOL simulation to assess their impact on electrochemical performance and transport behavior. The results reveal that although porosity variations have minimal effect on polarization at low voltages, they significantly influence internal pressure, species distribution, and gas evacuation at higher loads. A notable finding is that reversing stepwise porosity—placing high porosity near the membrane rather than the channel—can alleviate oxygen accumulation and improve current density. A multi-factor comparison highlights this reversed configuration as the most favorable among the tested strategies. The proposed modeling approach effectively connects porous media theory and system-level electrochemical analysis, offering a flexible platform for the future design of porous electrodes in PEMWE and other energy conversion systems
Genetics of monozygotic twins reveals the impact of environmental sensitivity on psychiatric and neurodevelopmental phenotypes
Get PDFIndividual sensitivity to environmental exposures may be genetically influenced. This genotype-by-environment interplay implies differences in phenotypic variance across genotypes, but these variants have proven challenging to detect. Genome-wide association studies of monozygotic twin differences are conducted through family-based variance analyses, which are more robust to the systemic biases that impact population-based methods. We combined data from 21,792 monozygotic twins (10,896 pairs) from 11 studies to conduct one of the largest genome-wide association study meta-analyses of monozygotic phenotypic differences, in children, adolescents and adults separately, for seven psychiatric and neurodevelopmental phenotypes: attention deficit hyperactivity disorder symptoms, autistic traits, anxiety and depression symptoms, psychotic-like experiences, neuroticism and wellbeing. The proportions of phenotypic variance explained by single-nucleotide polymorphisms in these phenotypes were estimated (h2 = 0–18%), but were imprecise. We identified 13 genome-wide significant associations (single-nucleotide polymorphisms, genes and gene sets), including genes related to stress reactivity for depression, growth factor-related genes for autistic traits and catecholamine uptake-related genes for psychotic-like experiences. This is the largest genetic study of monozygotic twins to date by an order of magnitude, evidencing an alternative method to study the genetic architecture of environmental sensitivity. The statistical power was limited for some analyses, calling for better-powered future studies
Taxes to red and processed meat to promote sustainable and healthy diets in Mexico
Get PDFBackgroundConsumption of red and processed meat is above sustainable and healthy dietary targets in Mexico. Policies to promote greater adherence such as taxing meat are needed to reduce consumption. Here, we evaluated how price increases to red and processed meat could shift consumption for meat as well as other key food groups.MethodsUsing data from the Mexican National Household Income and Expenditure Survey (2018, 2020, 2022), we estimated own- and cross-price elasticities of demand for 10 food groups. These were used to predict changes in quantity demanded of each food group according to price increase scenarios.ResultsPrice increases to meat increased demand for substitutes such as fruits and vegetables, legumes, poultry, and seafood, and reduced demand for salty snacks, sweets and sugary beverages. Substantial increases to the price of processed meat markedly reduced processed meat consumption, increased consumption of protein- and nutrient-rich foods, and resulted in more modest levels of red meat consumption. Lower-income groups were more sensitive to price increases but still met dietary recommendations for meat and substituted these foods with alternatives such as legumes and seafood.ConclusionsIncreasing the price of red and processed meat through a tax may promote greater adherence to sustainable and healthy dietary targets in Mexico. It simultaneously increased demand for healthier substitutes, and reduced demand for unhealthy complements. Substantially raising the price of processed meat only may be an effective strategy for addressing diet-related risk factors, while delivering environmental benefits. Additionally, meat taxes have the potential to promote improvements in diet quality and equitable health outcomes
Dynamic rationality and disproportionate belief
Get PDFI argue that rationality does not always require proportioning one’s beliefs to one’s evidence. I consider cases in which an agent’s evidence deteriorates over time, revealing less about the world or the agent’s location than their earlier evidence. I claim that the agent should retain beliefs that were supported by the earlier evidence, even if they are no longer supported by the later evidence. Failing to do so would violate an attractive principle of epistemic conservatism; it would foreseeably decrease the accuracy of the agent’s beliefs; it would make the agent susceptible to simple Dutch Books; it would allow them to manipulate their evidence to increase their confidence in desirable propositions over which they have no control. I defend the background assumption that dynamic considerations are relevant to epistemic rationality
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