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Wrinkle topographies have been studied as simple, versatile, and in some cases biomimetic surface functionalization strategies. To fabricate surface wrinkles, one material phenomenon employed is the mechanical-instability-driven wrinkling of thin films, which occurs when a deforming substrate produces sufficient compressive strain to buckle a surface thin film. Although thin-film wrinkling has been studied on shape-changing functional materials, including shape-memory polymers (SMPs), work to date has been primarily limited to simple geometries, such as flat, uniaxially-contracting substrates. Thus, there is a need for a strategy that would allow deformation of complex substrates or 3D parts to generate wrinkles on surfaces throughout that complex substrate or part. Here, 4D printing of SMPs is combined with polymeric and metallic thin films to develop and study an approach for fiber-level topographic functionalization suitable for use in printing of arbitrarily complex shape-changing substrates or parts. The effect of nozzle temperature, substrate architecture, and film thickness on wrinkles has been characterized, as well as wrinkle topography on nuclear alignment using scanning electron microscopy, atomic force microscopy, and fluorescent imaging. As nozzle temperature increased, wrinkle wavelength increased while strain trapping and nuclear alignment decreased. Moreover, with increasing film thickness, the wavelength increased as well.

 

Community monitoring can track environmental phenomena, resource use, and natural resource management processes of concern to community mem- bers. It can also contribute to planning and decision-making and empower community members in resource management. While community moni- toring that addresses the environmental crisis is growing, it also gathers data on other global challenges: climate change, social welfare, and health. Some environmental community monitoring programs are challenged by limited collective action and community participation, insufficient state re- sponsiveness to data and proposals, and lack of sustainability over time. Addi- tionally, community members monitoring the environment are increasingly harassed and sometimes killed. Community monitoring is more effective with improved data collection, improved data management and sharing, and stronger efforts to meet community information needs, enable conflict resolution, and strengthen self-determination. Other promising areas for development are further incorporating governance issues, embracing integrated approaches at the community level, and establishing stronger links to national and global frameworks. 

Disrupting the emergence and evolution of potentially violent online extremist movements is a crucial challenge. Extremism research has analyzed such movements in detail, focusing on individual- and movement-level characteristics. But are there system-level commonalities in the ways these movements emerge and grow? Here we compare the growth of the Boogaloos, a new and increasingly prominent U.S. extremist movement, to the growth of online support for ISIS, a militant, terrorist organization based in the Middle East that follows a radical version of Islam. We show that the early dynamics of these two online movements follow the same mathematical order despite their stark ideological, geographical, and cultural differences. The evolution of both movements, across scales, follows a single shockwave equation that accounts for heterogeneity in online interactions. These scientific properties suggest specific policies to address online extremism and radicalization. We show how actions by social media platforms could disrupt the onset and ‘flatten the curve’ of such online extremism by nudging its collective chemistry. Our results provide a system-level understanding of the emergence of extremist movements that yields fresh insight into their evolution and possible interventions to limit their growth.

 

We show that malicious COVID-19 content, including racism, disinformation, and misinformation, exploits the multiverse of online hate to spread quickly beyond the control of any individual social media platform. We provide a first mapping of the online hate network across six major social media platforms. We demonstrate how malicious content can travel across this network in ways that subvert platform moderation efforts. Machine learning topic analysis shows quantitatively how online hate communities are sharpening COVID-19 as a weapon, with topics evolving rapidly and content becoming increasingly coherent. Based on mathematical modeling, we provide predictions of how changes to content moderation policies can slow the spread of malicious content.

 

Multidisciplinary approaches to conservation and wildlife management are often e ective in addressing complex, multi-factor problems. Emerging elds such as conservation physiology and conservation behaviour can provide innovative solutions and management strategies for target species and systems. Sensory ecology combines the study of ‘how animals acquire’ and process sensory stimuli from their environments, and the ecological and evolutionary signi cance of ‘how animals respond’ to this information. We review the bene ts that sensory ecology can bring to wildlife conservation and management by discussing case studies across major taxa and sensory modalities. Conservation practices informed by a sensory ecology approach include the amelioration of sensory traps, control of invasive species, reduction of human–wildlife con icts and relocation and establishment of new populations of endangered species. We illustrate that sensory ecology can facilitate the understanding of mechanistic ecological and physiological explanations underlying particular conservation issues and also can help develop innovative solutions to ameliorate conservation problems. 

This essay discusses impacts of COVID-19 on food access for Indigenous individuals in Alaska, drawing on a collaborative study initiated by the Indigenous Foods Knowledges Network. Key lessons include: • The COVID-19 pandemic has exacerbated existing challenges for Alaska Natives in accessing traditional and store-bought foods. • The strength of Indigenous cultural and economic practices such as food sharing networks helped mitigate these challenges. • Policies and programs that support access to traditional foods and Indigenous sovereignty strengthen the ability of individuals and communities to respond to significant events that break down supply chains and restrict mobility.