Benthic macroalgae (including brown macroalgae or kelp) constitute one of the largest contributors to coastal primary production, but their ability to store and sequester carbon remains uncertain. Here, we use a numerical model of the flow/kelp interactions to study how tidal currents interact with an idealised numerical model of a giant kelp (Macrocystis pyrifera) forest, intending to better understand the potential for kelp growth in nutrient-limited conditions and the export of important tracers such as dissolved organic carbon. We calibrate and test our model using observations of currents within and surrounding a kelp forest in Southern California. By varying the density of kelp in our model, we find that there is a kelp density that maximises the export of tracer released from the kelp forest. Since the tracer advection/diffusion equation is linear with respect to the tracer concentration, the same kelp density corresponds to the maximum uptake for a tracer with a constant far-field concentration. The density at which this maximum occurs coincides with the density typical of natural kelp forests, where kelp growth may be limited by the uptake of dissolved nutrients from the surrounding water. Additionally, the drag induced on the tidal currents by the kelp forest results in a mean circulation through the kelp forest and a mean displacement of the kelp forest canopy.

All field scientists involved with weed management understand the importance of accurate weed identification and appreciate the need for widely recognized common names. USDA played a pivotal and critical role with the effort to advance our discipline while weed science was in its infancy.

The U.S. Department of Agriculture–Agricultural Research Service (USDA-ARS) has been a leader in weed science research covering topics ranging from the development and use of integrated weed management (IWM) tactics to basic mechanistic studies, including biotic resistance of desirable plant communities and herbicide resistance. ARS weed scientists have worked in agricultural and natural ecosystems, including agronomic and horticultural crops, pastures, forests, wild lands, aquatic habitats, wetlands, and riparian areas. Through strong partnerships with academia, state agencies, private industry, and numerous federal programs, ARS weed scientists have made contributions to discoveries in the newest fields of robotics and genetics, as well as the traditional and fundamental subjects of weed–crop competition and physiology and integration of weed control tactics and practices. Weed science at ARS is often overshadowed by other research topics; thus, few are aware of the long history of ARS weed science and its important contributions. This review is the result of a symposium held at the Weed Science Society of America’s 62nd Annual Meeting in 2022 that included 10 separate presentations in a virtual Weed Science Webinar Series. The overarching themes of management tactics (IWM, biological control, and automation), basic mechanisms (competition, invasive plant genetics, and herbicide resistance), and ecosystem impacts (invasive plant spread, climate change, conservation, and restoration) represent core ARS weed science research that is dynamic and efficacious and has been a significant component of the agency’s national and international efforts. This review highlights current studies and future directions that exemplify the science and collaborative relationships both within and outside ARS. Given the constraints of weeds and invasive plants on all aspects of food, feed, and fiber systems, there is an acknowledged need to face new challenges, including agriculture and natural resources sustainability, economic resilience and reliability, and societal health and well-being.

This case study investigates strategies used by the NGO Leonard Cheshire Disability Zimbabwe (LCDZ) to promote the SRHRs of girls and young women with disabilities in Zimbabwe. The findings show that LCDZ employed a combination of six strategies. These are: (1) building practical knowledge on SRHRs; (2) increasing community awareness and sensitivity; (3) providing SRHRs-related education; (4) enhancing access to justice and related services for survivors of sexual violence; (5) delivering assistive devices; and (6) promoting the livelihoods and economic empowerment. LCDZ made use of multi-stakeholder partnerships to implement these strategies, leveraging complementary skills and experience in the promotion of SRHRs. In each of these strategies, girls and young women with disabilities are the target group, with other stakeholders brought together to support them.

Most major nonviolent civil resistance campaigns target autocratic regimes. Yet, most dictators are toppled by their close supporters, not civilian protesters. Building on theories of strategic interactions between leaders, security agents, and protesters, we make three core claims: first, protesters are relatively less likely to mount a major nonviolent uprising against dictatorships with personalized security forces; secondly, personalized security forces are more likely to repress realized protest; and, thirdly, security force personalization shapes the prospects for success of mass uprisings in promoting democratic transitions. We leverage new data on security force personalization—a proxy for loyal security agents—and major nonviolent protest campaigns to test these expectations. Our theory explains why many dictatorships rarely face mass protest mobilization and why uprisings that are met with violent force often fail in bringing about new democracies.

Compatibilist libertarianism claims that alternate possibilities for action at the agential level are consistent with determinism at the physical level. Unlike traditional compatibilism about alternate possibilities, involving conditional or dispositional accounts of the ability to act, compatibilist libertarianism offers us unqualified modalities at the agential level, consistent with physical determinism, a potentially big advance. However, I argue that the account runs up against two problems. Firstly, the way in which the agential modalities are generated talks past the worries of the incompatibilist in the traditional free will problem. As such, it fails to dispel the worries that determinism generates for the incompatibilist. Secondly, in spite of the ingenious use of the supervenience thesis and multiple realizability, the position still allows us to generate the old worry that determinism at the physical level would mean no alternate possibilities at the level of agency. In particular, I develop a new example, the ‘atomic slit case’ that demonstrates how physical level information is salient to what is possible at the agential level, motivating incompatibilism.

An appealing interpretation of Aristotle's moral psychology argues that character virtue sets the goal of the good life. On that view, practical wisdom or phronēsis supplies only the means toward the end that is grasped by the character virtues. Yet, this view has trouble accounting for the supremacy of the contemplative life, which is clearly the best life in the paradigmatic or strict sense for Aristotle. In this paper, I argue that the intellect plays a role for Aristotle in realizing the priority of the contemplative life and integrating it into our practical lives as a whole.