Search for: All records

Natural building materials like clay soils and plant fibres are undergoing a renaissance in ecological design and architecture. Nonetheless, design creativity and fabrication using natural materials have mostly relied on manual techniques, such as cob and rammed earth, which are limited to heavy mass assemblies in rectilinear geometries with thick straight lines. Introducing digital fabrication with diverse ranges of processing parameters to natural materials can introduce novel patterns, textures, geometries and performances. This study explores the integration of 3D printing with soil- and plant-based fibre material recipes with high fibre content, culminating in digitally designed vessels inspired by traditional basketry protocols. Computational models of basket ‘wall’ profile typologies, from vertical to convex and concave geometries, were evaluated for their resulting printed patterns and structural stability. The texture results achieved in this work aim to challenge the digital aesthetics dominated by petroleum-based or thermoplastic pastes. Distinct printing qualities and pattern resolution were shown to be achieved for different fibre types, from wheat straw to longer hemp and banana fibres. By leveraging digital tools to reimagine ancient materials and techniques, this research aims to foster a deeper connection between constructed forms and our relationship with soil and plants as essential stewardships required for environmental agency in creative and accessible design. Exhibited in several design venues, the resulting artefacts showcase novel fusions of material surface patterns, crafted through machine deposition, embodying traditional inspirations in sustainable digital design. 

Abstract An edge‐coloured graph is said to berainbowif no colour appears more than once. Extremal problems involving rainbow objects have been a focus of much research over the last decade as they capture the essence of a number of interesting problems in a variety of areas. A particularly intensively studied question due to Keevash, Mubayi, Sudakov and Verstraëte from 2007 asks for the maximum possible average degree of a properly edge‐coloured graph on vertices without a rainbow cycle. Improving upon a series of earlier bounds, Tomon proved an upper bound of for this question. Very recently, Janzer–Sudakov and Kim–Lee–Liu–Tran independently removed the term in Tomon's bound, showing a bound of . We prove an upper bound of for this maximum possible average degree when there is no rainbow cycle. Our result is tight up to the term, and so, it essentially resolves this question. In addition, we observe a connection between this problem and several questions in additive number theory, allowing us to extend existing results on these questions for abelian groups to the case of non‐abelian groups. 

ABSTRACT Below-ground carbon transformations that contribute to healthy soils represent a natural climate change mitigation, but newly acquired traits adaptive to climate stress may alter microbial feedback mechanisms. To better define microbial evolutionary responses to long-term climate warming, we study microorganisms from an ongoingin situsoil warming experiment where, for over three decades, temperate forest soils are continuously heated at 5°C above ambient. We hypothesize that across generations of chronic warming, genomic signatures within diverse bacterial lineages reflect adaptations related to growth and carbon utilization. From our bacterial culture collection isolated from experimental heated and control plots, we sequenced genomes representing dominant taxa sensitive to warming, including lineages of Actinobacteria, Alphaproteobacteria, and Betaproteobacteria. We investigated genomic attributes and functional gene content to identify signatures of adaptation. Comparative pangenomics revealed accessory gene clusters related to central metabolism, competition, and carbon substrate degradation, with few functional annotations explicitly associated with long-term warming. Trends in functional gene patterns suggest genomes from heated plots were relatively enriched in central carbohydrate and nitrogen metabolism pathways, while genomes from control plots were relatively enriched in amino acid and fatty acid metabolism pathways. We observed that genomes from heated plots had less codon bias, suggesting potential adaptive traits related to growth or growth efficiency. Codon usage bias varied for organisms with similar 16Srrnoperon copy number, suggesting that these organisms experience different selective pressures on growth efficiency. Our work suggests the emergence of lineage-specific trends as well as common ecological-evolutionary microbial responses to climate change.IMPORTANCEAnthropogenic climate change threatens soil ecosystem health in part by altering below-ground carbon cycling carried out by microbes. Microbial evolutionary responses are often overshadowed by community-level ecological responses, but adaptive responses represent potential changes in traits and functional potential that may alter ecosystem function. We predict that microbes are adapting to climate change stressors like soil warming. To test this, we analyzed the genomes of bacteria from a soil warming experiment where soil plots have been experimentally heated 5°C above ambient for over 30 years. While genomic attributes were unchanged by long-term warming, we observed trends in functional gene content related to carbon and nitrogen usage and genomic indicators of growth efficiency. These responses may represent new parameters in how soil ecosystems feedback to the climate system.