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.

There is a widening gap between the medical model of dementia and critical sociological perspectives of the condition. Given the relative failure of reductionism in dementia and its rising prevalence, consideration of the utility of these critical viewpoints is warranted. This article considers how these ideas, which challenge some prevailing assumptions about dementia, can be meaningfully applied in conjunction, rather than in competition, with conventional clinical ideas. To illustrate this, current perspectives on selfhood, biopolitics, citizenship and post-humanism are discussed. This article may also help to articulate sociologically oriented approaches already used by some clinicians and legitimise the time and attention needed to explore and deliver these. We support the view that dementia is an episteme in the making and that different traditions and dispositions can fruitfully collide to enliven interdisciplinary conversations about dementia and dementia care.

In March 2020, the government of the United Kingdom advised all people aged 70 and above to self-isolate stringently for a minimum of 12 weeks in response to COVID-19. The British Society of Gerontology criticised the government for ignoring individual differences, deeming the approach ageist. Former British Geriatrics Society president David Oliver contested accusations of ageism, arguing that the approach was pragmatic discrimination based on epidemiological evidence. This debate catalyses core gerontological tensions regarding ageism, discrimination, categorisation and heterogeneity. A critical realist perspective reveals that both the government and gerontology are struggling to negotiate these irresolvable tensions. Contrary to the binary debate, age-based isolation simultaneously represents pragmatic discrimination and value-driven ageism. However, it does so partly because it relies on a chronologic epistemology that positions age as a potent biosocial axis of meaningful difference, thereby reflecting gerontology's own ageism. The ethical purism of gerontological accusations of ageism is thus somewhat misplaced, potentially obscuring an opportunity for reflection on value-laden engagements with age in social research.

The uncommon sodium rare-earth phosphate mineral vitusite-(Ce) (Na3RE(PO4)2) can be considered as the extreme product of sodium and rare-earth substitution in the apatite structure. Lesser amounts of substitution provide sodium and rare-earth-bearing apatites up to about 80 mol.% exchange; beyond this point vitusite is the stable phase. The structure of vitusite, determined previously from a synthetic analogue, can also be considered as a derivative from apatite, but with cations exchanged on sites normally occupied by anions. Vitusite can therefore be considered as a sodium- and rare-earthrich apatite end-member, with a distinct, but apatite-derived, structure, formed in highly persodic and high rare-earth environments. From an examination of the literature on diffusion in apatite, vitusite in principle could be formed from apatite sensu stricto by subsolidus diffusion in response to late-stage Naand RE-rich hydrothermal fluids.

There are a number of different types of involuntary saccadic eye movements which differ from normal saccades in that they take the fovea away from its target. This article presents a classification and description of these abnormal eye movements and indicates how they may be used to increase the precision of neurologic diagnosis.

A Chebyshev set is a subset of a normed linear space that admits unique best approximations. In the first part of this paper we present some basic results concerning Chebyshev sets. In particular, we investigate properties of the metric projection map, sufficient conditions for a subset of a normed linear space to be a Chebyshev set, and sufficient conditions for a Chebyshev set to be convex. In the second half of the paper we present a construction of a nonconvex Chebyshev subset of an inner product space.