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Spatiotemporal variation in size-dependent growth rates in small isolated populations of Arctic charr (Salvelinus alpinus)
No full textAs a key life-history trait, growth rates are often used to measure individual performance and to inform parameters in demographic models. Furthermore, intraspecific trait variation generates diversity in nature. Therefore, partitioning out and understanding drivers of spatiotemporal variation in growth rate is of fundamental interest in ecology and evolution. However, this has rarely been attempted owing to the amount of individual-level data required through both time and space, and issues with missing data in important covariates. Here, we implemented a Bayesian state-space model using individual-level data from 20 populations of Arctic charr (Salvelinus alpinus) across 15 capture occasions, which allowed us to: (i) integrate over the uncertainty of missing recapture records; (ii) robustly estimate size-dependence; and (iii) include a covariate (water temperature) that contained missing data. Interestingly, although there was substantial spatial, temporal and spatiotemporal variation in growth rate, this was only weakly associated with variation in water temperature and almost entirely independent of size, suggesting that spatiotemporal variation in other environmental conditions affected individuals across sizes similarly. This fine-scale spatiotemporal variation emphasizes the importance of local conditions and highlights the potential for spatiotemporal variation in a size-dependent life-history trait, even when environmental conditions are apparently very similar
Variation in wood density across South American tropical forests
Get PDFWood density is a critical control on tree biomass, so poor understanding of its spatial variation can lead to large and systematic errors in forest biomass estimates and carbon maps. The need to understand how and why wood density varies is especially critical in tropical America where forests have exceptional species diversity and spatial turnover in composition. As tree identity and forest composition are challenging to estimate remotely, ground surveys are essential to know the wood density of trees, whether measured directly or inferred from their identity. Here, we assemble an extensive dataset of variation in wood density across the most forested and tree-diverse continent, examine how it relates to spatial and environmental variables, and use these relationships to predict spatial variation in wood density over tropical and sub-tropical South America. Our analysis refines previously identified east-west Amazon gradients in wood density, improves them by revealing fine-scale variation, and extends predictions into Andean, dry, and Atlantic forests. The results halve biomass prediction errors compared to a naïve scenario with no knowledge of spatial variation in wood density. Our findings will help improve remote sensing-based estimates of aboveground biomass carbon stocks across tropical South America
Brief report:False memory formation in autism: The role of relational processing at study
Get PDFPurpose: Several studies have investigated false memory production in autistic adults, yet it remains unclear whether susceptibility to false memories differs from non-autistic adults and what mechanisms might contribute to any differences. This study examines the mechanisms behind false memory formation in autistic adults using the Deese-Roediger-McDermott (DRM) paradigm. Methods: Participants studied DRM word lists designed to activate a critical word (the ‘critical lure). To examine false memory formation and associative processing, participants completed three tasks: a standard recognition test to measure false memory rates, a word stem completion task to assess implicit priming of the critical lure, and a free association task to evaluate explicit associative processing. Results: Autistic individuals showed comparable rates of false memories as non-autistic adults (i.e., falsely reporting having studied the critical lure), were as likely to mention the critical lure on the free association task but showed no tendency to complete word stems with the critical lure when implicitly primed to do so. Conclusion: These findings suggest that autistic adults may rely less on spontaneous spreading of semantic activation during encoding but are capable of engaging in explicit associative processing when directed. The results provide valuable insights into the mechanisms underlying false memory formation in autism.</p
Familial similarity and heritability of personality traits and life satisfaction are higher than shown in typical single-method studies
Get PDFPersonality trait similarity among ordinary relatives is surprisingly low, with parent–offspring and sibling–sibling correlations usually r ≤ .15. We explain why these correlations are biased in typical single-method studies and argue that this problem can only be addressed with multimethod designs. We also explain why ordinary relative comparisons can provide a more generalizable way of estimating (additive, narrow-sense) heritability than the better known twin comparisons. In a sample of parent–offspring (Npairs = 522), sibling–sibling (Npairs = 388), and second-degree relative pairs (Npairs = 476), who rated their Big Five personality traits and life satisfaction and were each rated by an independent informant (Nparticipants = 2,258 + informants), we found that parent–offspring and sibling correlations were about one third higher than typically shown (r ≈ .20). Based on the ordinary relative comparisons, the heritability of personality traits and life satisfaction was about 40%, compared with about 26% typical to self-report studies. Life satisfaction was as heritable as personality traits, sharing about 80% of its genetic variance with neuroticism, extraversion, and conscientiousness. About half of life satisfaction’s phenotypic correlations with neuroticism and extraversion and its entire correlation with conscientiousness were explained by shared genetic factors. Using data from a larger sample of relatives with only self-reports (Nparticipants = 32,004; Npairs = 24,118), we provide further evidence that growing up together does not make people more similar. The results were consistent for both aggregate traits and individual items. Only multimethod designs can accurately reveal traits’ similarity among relatives and their genetic and environmental transmission
Purification of Syngas to using Process Swing Adsorption with Purge Gas Recirculation (PSA-SPUR) for carbon negative hydrogen
Get PDFOverview of the DemonstrationAs the world moves to decarbonise and better secure the energy sector against climate change and global conflict, hydrogen is increasingly seen as a critical pathway to a secure and diverse energy mix. However, current hydrogen generation is highly sensitive to fossil fuel industry events, such as price shocks or supply chain issues, necessitating a broader mix of hydrogen production methods.This demonstration showcases a suite of technologies, demonstrating the potential of the Wild Hydrogen Rising Pressure Reformer (RiPR) to generate carbon-negative hydrogen by separating carbon dioxide from other energy gases created in a RiPR using a pressure swing adsorption (PSA) system.Key Findings:• The project successfully increased hydrogen concentration from 30% to 70% by volume, highlighting the potential of PSA technology for syngas purification.• A carbon dioxide and methane mixture was also produced, which could be further refined using additional PSA steps or alternative separation methods.• PSA-SPUR technology demonstrated CO₂ capture at over approximately 95% purity, providing an initial pathway for carbon sequestration
Managing free-roaming domestic dog populations using surgical sterilisation: a randomised controlled trial
Get PDFFree-roaming domestic dogs (FRDs) are among the most abundant carnivores on earth and have coexisted with humans for over 15,000 years, yet increases in negative interactions and the transmission of zoonotic diseases, precipitates calls for population management. Despite significant investment in FRD sterilisation in India, where rabies is endemic, there is limited evidence of its impact on reducing FRD population sizes. Therefore, robust evaluation of the effectiveness of fertility control programmes is necessary. To address this, we implemented a Before After Control Intervention (BACI) framework in the first multi-site randomised controlled trial for the sterilisation of FRDs. We conducted single intensive sterilisation campaigns in five areas, achieving female sterilisation coverages of 58-66%. We observed a decrease in puppies and lactating females and a reduction in residents' reports of barking, a common problem associated with FRDs. There were no significant differences in adult FRD counts between intervention and control sites during the 2-year follow-up. However, unmeasured immigration into and emigration out of study areas may have confounded counts. One-off, albeit intense, sterilisation campaigns in open populations require substantial investment and are unlikely to reduce population size in isolation, though there may be some reduction in problematic behaviours and improved animal welfare.<br/
Benchmarking and tailoring electric vehicle policies to stimulate adoption
No full textElectric vehicle (EV) adoption is heralded as one of the most effective solutions for the decarbonization of road transport systems. However, the heterogeneous rate of EV adoption across geographies, coupled with observed or perceived slowdowns in consumer market acceptance, has raised concerns about this technology transition. Utilizing Rogers’ Diffusion of Innovations theory, this paper develops a key component of establishing an EV adoption policy roadmap: policy benchmarking. The policy roadmaps of leading countries in EV adoption, as well as those of countries where EV adoption is accelerating or expected to accelerate in the near term, are benchmarked to derive actionable insights. This benchmarking effort is presented in the context of a case study on developing an EV adoption policy roadmap tailored to the United Arab Emirates (UAE). While the resulting roadmap addresses the UAE’s local context and segmented consumer types, including early adopters and the “early majority,” the methodology employed provides a generalizable framework for policymakers in any geography seeking to advance EV adoption. Using a sociotechnical perspective, we evaluate the policy mechanisms for their ability to reduce friction points and propose recommendations applicable across diverse contexts. Our findings highlight the criticality of establishing necessary infrastructure, particularly for EV charging, alongside the importance of user awareness and education programs that are both tailored to local contexts and adaptable to global best practices. This approach underscores the potential for policymakers to create robust, enduring strategies that accelerate EV adoption globally
An efficient active-set method with applications to sparse approximations and risk minimization
Get PDFIn this paper we present an efficient active-set method for the solution of convex quadratic programming problems with general piecewise-linear terms in the objective, with applications to sparse approximations and risk-minimization. The algorithm is derived by combining a proximal method of multipliers (PMM) with a standard semismooth Newton method (SSN), and is shown to be globally convergent under minimal assumptions. Further local linear (and potentially superlinear) convergence is shown under standard additional conditions. The major computational bottleneck of the proposed approach arises from the solution of the associated SSN linear systems. These are solved using a Krylov-subspace method, accelerated by certain novel general-purpose preconditioners which are shown to be optimal with respect to the proximal penalty parameters. The preconditioners are easy to store and invert, since they exploit the structure of the nonsmooth terms appearing in the problem’s objective to significantly reduce their memory requirements. We showcase the efficiency, robustness, and scalability of the proposed solver on a variety of problems arising in risk-averse portfolio selection, L1-regularized partial differential equation constrained optimization, quantile regression, and binary classification via linear support vector machines. We provide computational evidence, on real-world datasets, to demonstrate the ability of the solver to efficiently and competitively handle a diverse set of medium- and large-scale optimization instances.</p
Bystander activation across a TAD boundary supports a cohesin-dependent transcription cluster model for enhancer function
Get PDFMammalian enhancers can regulate genes over large genomic distances, often skipping over other genes. Despite this, precise developmental regulation suggests that mechanisms exist to ensure enhancers only activate their correct targets. Sculpting of three-dimensional chromosome organization through cohesin-dependent loop extrusion is thought to be important for facilitating and constraining enhancer action. The boundaries of topologically associating domains (TADs) are thought to prevent enhancers acting on genes in adjacent TADs. However, there are examples where enhancers appear to act across TAD boundaries, but it has remained unclear whether a single enhancer can simultaneously activate genes in different TADs. Here we show that some Shh enhancers can activate transcription concurrently not only at Shh but also at Mnx1 located in an adjacent TAD. This occurs in the context of a chromatin conformation maintaining genes and enhancers in close proximity and is influenced by cohesin. To our knowledge, this is the first report of two endogenous mammalian genes transcribed concurrently under the control of the same enhancer and across a TAD boundary. These findings have implications for understanding the design rules of gene regulatory landscapes and are consistent with a transcription cluster model of enhancer-promoter communication
Transcriptomic characterization of transitioning cell types in the skin of Atlantic salmon
Get PDFBACKGROUND: The skin maintains the body's integrity and serves as the first line of defence against pathogens, stressors and mechanical injuries. Despite the global significance of salmon in aquaculture, how the transcriptomic profile of cells varies during wound healing remains unexplored. Teleost's skin contains adult pluripotent cells that differentiate into various tissues, including bone, cartilage, tendon, ligament, adipose, dermis, muscle and connective tissue within the skin. These cells are pivotal for preserving the integrity of skin tissue throughout an organism's lifespan and actively participate in the wound healing processes. In this study, we characterize the transcriptomic profiles of putative mesenchymal stromal cells (fibroblast-like adult stem cells) in healthy Atlantic salmon tissue and during the wound healing process.RESULTS: Single-nucleus sequencing and spatial transcriptomics were used to detect transcriptomic changes occurring during wound healing that are commonly associated with mesenchymal stromal cells. We followed the transcriptomic activity of these cells during an in vivo wound healing time course study showing that these cells become more transcriptionally active during the remodelling stage of wound healing. The changes detected give insights into the potential differentiation pathways leading to osteogenic and fibroblast lineages in the skin of Atlantic salmon.CONCLUSIONS: We chart the transcriptomic activity of subclusters of putative differentiating stromal cells during the process of wound healing for the first time, revealing different spatial niches of the various putative MSC subclusters, and setting the stage for further investigation of the manipulation of transitioning cell types to improve fish health.</p
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