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Foraging niche partitioning by Antarctic petrels and snow petrels breeding in sympatry
No full textBreeding in sympatry may increase competition among closely related species, especially when these species are colonial central-place foragers. Niche partitioning, for example through segregation in space, time, habitat or diet, can help mitigate such competition. Here, we tested for differences in the movement, space use and habitat selection of 2 closely related pelagic seabirds, the Antarctic petrel Thalassoica antarctica and the snow petrel Pagodroma nivea, breeding sympatrically in Antarctica. To do so, we tracked the foraging movements of breeders from a large colony at Svarthamaren, Dronning Maud Land, using GPS loggers. We found that during incubation, Antarctic petrels travelled faster and trips were longer in duration and travel distance than those of snow petrels. Antarctic petrels foraged predominantly northeast of the colony, whereas snow petrels foraged farther west, closer to the coastline. This led to spatial segregation, with <15% mean overlap between foraging areas of the 2 species. Snow petrels foraged more frequently among sea ice, and closer to the sea-ice edge than Antarctic petrels. These results support the hypothesis that the foraging niches of the 2 species are differentiated in geographical space and habitat, possibly mediated by differences in size and therefore flight performance. Our results imply that foraging snow petrels are more directly dependent on sea ice than Antarctic petrels, and consequently more immediately affected by loss of sea ice due to climate change
Cities on Fire: Towards an Elemental Urbanism in the Anthropocene
No full textThis intervention outlines a new way of thinking about the growing entanglements between fire and urban life in the Anthropocene, calling for a dialogue between urban studies and elemental geographies as a conceptual lens that addresses the changing nature of nature in contemporary urban worlds. As wildfires increasingly impact cities-destroying infrastructure and property, displacing populations and altering air quality across vast distances-fire emerges not only as risk and hazard but as an elemental force reshaping the city's political, material, and conceptual foundations. Our aim is twofold. First, we open a debate on an emerging urban condition of the Anthropocene where fire assumes a reinvigorated presence. Second, exploring analytical pathways for rethinking cities on fire, we discuss connections between urban studies and elemental geographies-a growing subfield of cultural and political geography which engages with the elements as a way of thinking with Earth's materialities. The resurgence of fire in the city, we contend, signals the growing presence of 'elemental exposures' resulting from global environmental change and Anthropogenic climate and ecological emergencies. Following a review of fire scholarship within urban studies, we suggest an elemental rethinking of fire-not as a spatially distant or exceptional event, but as a shared, co-constitutive, agentic, and persistent presence demanding collective responsibility and adaptation as well as novel ways of conceptualising city-nature relationships. The resulting urban pyropolitics frames cities as dynamic, more-than-human sites of climate transformation and vulnerability, highlighting the unequal distribution of elemental exposure in the Anthropocene city and its racialised, gendered, and classed dimensions
Integrated rotating packed bed reactor design for post combustion carbon capture: Parametric analysis, optimization and economic viability
No full textWorldwide deployment of carbon capture (CC) technologies has become inevitable due to vast usage of fossil or carbon-based fuels. To do so, chemical absorption-based CC technology has drawn significant attention due to its potential of capturing higher rates of CO2 even at lower pressure ranges. Nonetheless, this technique is an energy intensive and requires a huge amount of capital for its deployment. In contrast, rotating packed bed (RPB) reactor technology is relatively new and can provide an ultimate solution to conventional absorption systems due to its lower cost and efficient operation. However, a full-scale CC using RPB technology has been underexplored, with prior studies limited to lab-scale setups or isolated unit designs, often overlooking simultaneous modeling of absorber and regenerator into a continuous loop. Therefore, this study fills the current gap by presenting a comprehensive design and analysis of a full-scale post combustion carbon capture (PCC) process evaluating three different MEA concentrations, i.e., 30, 45, and 60 wt%, and three lean loadings 0.16, 0.24, and 0.3. A cross-platform integration of Aspen Plus and MATLAB was employed to harness computational capabilities and accurately predict thermodynamic and transport properties. Initial parametric analysis demonstrated up to 90 % height reduction in the absorber and 80 % in the regenerator, with packing volumes shrinking by over 95 % compared to conventional packed beds. To capture the complex trade-offs between liquid-to-gas ratio (L/G), lean loading, rotor speeds, and Z/r ratios, a genetic algorithm–driven optimization was applied which resulted in up to 27 % reduction in total annualized cost (84 to 60.99 M224.6/tCO2 to $77.88/tCO2. These findings provide a robust, scalable framework that paves the way for next-gen energy and cost-efficient carbon capture solutions, offering an alternative to conventional systems
Towards optimal public health interventions for preventing obesity in children: a synopsis of a novel evidence synthesis
No full textAbstractBackground: Childhood obesity is a major public health concern worldwide, yet the best way to prevent it remains unknown.Objective(s): To determine what types of intervention strategy are most effective at preventing the development of obesity in children aged 5 to 18 years, as measured by change in body mass index (BMI), and to determine whether interventions work differentially in children with different characteristics associated with inequities. Design: Systematic reviews and statistical evidence syntheses. Eligibility criteria: Randomized controlled trials of dietary and/or activity interventions that aimed to prevent overweight or obesity in children and young people aged 5 to 18 years and reported outcomes at least 12 weeks after baseline. Non-randomized evidence was identified through an overview of systematic reviews. Sources of inequity of interest were those defined by the PROGRESS acronym: place, race/ethnicity, occupation (of parents), gender/sex, religion, education (of parents), socio-economic status and social capital.Data sources: Updating of an existing Cochrane Review, searching bibliographic databases up to February 2023, including MEDLINE, Embase, PsycINFO and CENTRAL on the Cochrane Library, international trial registers and grey literature databases, and examining reference lists. Results subgrouped by inequity factors were sought directly from trialists.Review methods: Cochrane Reviews followed standard Cochrane procedures. The main statistical synthesis was informed by a novel analytic framework developed iteratively through discussions with children and young people, schoolteachers and public health professionals. Methodology was developed to analyse the data using multi-level meta-regression. To examine the impact of inequity factors, we performed two stage meta-analysis of interactions, based on subgroup-level aggregate data collected directly from the trialists. We collected available information on intervention costs.Results: We included 172 trials in ages 5-11 and 74 in ages 12-18. In the main synthesis, of 204 trials from both reviews, we found interventions were effective on average (mean difference in standardized BMI −0.037, 95% credible interval −0.053 to −0.022, which would correspond to a reduction in a proportion of 2.3% with obesity to a proportion of approximately 2.1%). Larger effects were associated with physical activity rather than dietary interventions, after 12 months of follow up and in the older age group. The overview of non-randomized evidence included 24 systematic reviews, yielding mixed results. The investigation of inequity did not identify substantial differences in effectiveness according to PROGRESS characteristics, and there was very limited information about costs.Limitations: We were able to examine only the interventions that had been evaluated in studies identified for inclusion in the systematic reviews, which does not cover all possible intervention approaches. Conclusions: Interventions to prevent obesity in children aged 5-18 have a small beneficial effect on BMI on average but with considerable variation. A novel re-analysis of existing randomized trials failed to identify general intervention characteristics driving this variation. No evidence was identified to suggest that interventions increase (or decrease) health inequities.Future work: Future studies of the effects of interventions to prevent childhood obesity should routinely collect baseline characteristics around potential inequities
The Life of Form: Anthropology, Wittgenstein, and the Problem of Context
No full textWhat if anthropology's fundamental assumptions about cultural and social context were shaped by a philosopher many anthropologists have never engaged with? This book explores how, from the early twentieth century to the present day, anthropological ideas about context have been shaped by Ludwig Wittgenstein's evolving philosophy, often without anthropologists fully realizing it. It shows how Wittgenstein's philosophical journey mirrors anthropology's own theoretical transformations. Through careful analysis of key figures from Malinowski and Radcliffe-Brown to Geertz and contemporary theorists, Paolo Heywood reveals unexpected connections between philosophical developments and anthropological practice. The result is a surprising genealogy of how we came to think about culture, society, and everyday life the way we do. This intellectual history illuminates the hidden philosophical assumptions that continue to shape anthropological work today. It reveals how disciplines are shaped by ideas they've forgotten they borrowed, and the surprising ways such ideas evolve in new contexts
A fractional partition of unity finite element method for transient anomalous diffusion problems
Get PDFA fractional partition of unity finite element method is proposed for the solution of the transient anomalous diffusion equation. The Caputo integro-differential operator is employed to represent the fractional time-derivative in these problems. To approximate the Caputo fractional derivative, we propose a new numerical differentiation formula using quadratic splines. For the spatial discretization, we implement an enriched finite element method on unstructured meshes. In the present study, a category of exponential functions incorporating fractional orders is introduced as enrichment functions to refine the finite element approximation. These functions are designed to capture the fractional characteristics of the solution more effectively. By integrating these enrichment functions through the partition of unity framework, the method utilizes prior knowledge of the fractional problem, leading to a substantial enhancement in approximation accuracy while preserving the fundamental advantages of the traditional finite element method. Consequently, the proposed approach delivers precise numerical solutions even with coarse meshes and requires significantly fewer degrees of freedom compared to conventional finite element techniques. Moreover, the mesh resolution remains unaffected by variations in the fractional order, allowing for a consistent mesh structure regardless of changes in fractional parameters. Through extensive numerical simulations, we consistently verify the effectiveness of the proposed technique in achieving high levels of accuracy. This approach not only ensures reliable and precise results but also broadens the applicability of the finite element method, making it more capable of handling time-fractional transient diffusion problems that have traditionally been challenging for standard methods
An implicit hyperelastoplastic micropolar material point method for shear bands and size effects at finite strains
Get PDFStrain localisation and size effects remain difficult to capture in computational models of material failure, especially in geomechanics where large, heterogeneous deformations are typical. Classical continuum approaches lack intrinsic length scales, while most regularisation strategies introduce artificial gradient terms that are often heuristic and thermodynamically inconsistent. Micropolar theory offers a physically motivated alternative, but existing implementations are largely restricted to linearised or purely elastic settings, or combined with additional nonlocal paradigms. This work introduces the first implicit elastoplastic Material Point Method (MPM) that fully integrates nonlinear micropolar (Cosserat) theory with consistent numerical stabilisation. The framework is geometrically exact, thermodynamically consistent, and relies solely on micropolar regularisation to produce mesh-objective shear bands and size-dependent responses. Robustness is further enhanced by combining the Generalised Interpolation MPM (GIMPM) with ghost penalisation, mitigating long-standing MPM instabilities. Despite its constitutive simplicity, the model captures key features of localisation with a minimal set of physically meaningful parameters. Validation against finite-strain benchmark problems demonstrates its ability to reproduce mesh-independent failure patterns and microstructure-sensitive behaviour. The method thus provides a new, physically grounded regularisation framework for large-deformation localisation problems, with promising applications in geomechanics and other domains where microstructural effects are significant
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