Community structure, abundance, and morphology

. 2000. Community structure, abundance, and morphology. -Oikos 88: 48 -56. The role of interspecific competition in structuring communities has been a highly debated issue for the last two decades. The nonrandom nature of morphological patterns within communities has been at the center of this controversy. Null models addressing community-wide dispersions in morphology have produced equivocal results and may be based on assumptions that are too restrictive (e.g., competitive exclusion or displacement). If morphological distinctiveness allows species to escape competitive pressures and exhibit higher densities, then a positive relationship should exist between morphological dissimilarity and abundance. We develop a suite of models that evaluates patterns in abundance that are associated with the morphological proximity of a species to other competitors. We evaluated the relationship between morphological distance and abundance from a variety of morphological perspectives, from those representing strictly diffuse interactions to those representing only interactions between a species and its nearest neighbor in morphological space. These models were sufficiently powerful to detect positive associations between abundance and morphological differences in a nocturnal desert rodent guild for which the effects of competition on structure are well established. Models such as these may be more useful than traditional models evaluating morphological dispersions for many reasons. They do not require that communities reach equilibrium before competitive interactions give rise to deterministic structure. They do not suffer from limitations of potentially inaccurate faunal pools or from phylogenetic constraints. Lastly, they may be used as a diagnostic tool in comparative studies to determine the degree to which competitive interactions structure communities

The Role of the Gouy Phase in the Coherent Phase Control of the Photoionization and Photodissociation of Vinyl Chloride

We demonstrate theoretically and experimentally that the Gouy phase of a focused laser beam may be used to control the photo-induced reactions of a polyatomic molecule. Quantum mechanical interference between one- and three-photon excitation of vinyl chloride produces a small phase lag between the dissociation and ionization channels on the axis of the molecular beam. Away from the axis, the Gouy phase introduces a much larger phase lag that agrees quantitatively with theory without any adjustable parameters.Comment: 4 pages, 4 figure

"There's not enough knowledge out there": examining older adults' perceptions of digital technology use and digital inclusion classes

Older adults' definitions of digital technology, and experiences of digital inclusion sessions, were examined using qualitative approaches. Seventeen older adults (aged between 54 and 85) participated in two focus groups that each lasted approximately 90 minutes to explore how older adults understood technology within their lived experience. Interpretative Phenomenological Analysis yielded two main themes: Thirst for knowledge and a wish list for digital technology sessions. A separate content analysis was performed to identify what technology older adults identified as digital technology. This analysis revealed that the older adults most frequently defined digital technology as computers and telephones. The findings support the conclusions that this group of older adults, some of whom were 'successful users', have a wide knowledge of digital technology, are interested in gaining more skills, and desire knowledge acquisition through personalised one-to-one learning sessions

Exploring the psychological rewards of a familiar semirural landscape: connecting to local nature through a mindful approach

This study analyses a 53,000 word diary of a year engaging with nature through over 200 trips to a semi-rural landscape. Thematic analysis revealed two themes; the transition from observer to nature connectedness and the ways in which the natural environment was experienced once a connection was made. These themes are discussed in relation to theories that seek to explain the positive effect of nature and nature connectedness. The findings are important as they suggest that repeated engagement with local semi-rural countryside can lead to a mindful approach and psychological rewards that do not require travel into the wilderness. The work informs further research into outcomes and processes of nature based interventions such as: trip frequency, duration and diary keeping

Sporting embodiment: sports studies and the (continuing) promise of phenomenology

Whilst in recent years sports studies have addressed the calls ‘to bring the body back in’ to theorisations of sport and physical activity, the ‘promise of phenomenology’ remains largely under-realised with regard to sporting embodiment. Relatively few accounts are grounded in the ‘flesh’ of the lived sporting body, and phenomenology offers a powerful framework for such analysis. A wide-ranging, multi-stranded, and interpretatively contested perspective, phenomenology in general has been taken up and utilised in very different ways within different disciplinary fields. The purpose of this article is to consider some selected phenomenological threads, key qualities of the phenomenological method, and the potential for existentialist phenomenology in particular to contribute fresh perspectives to the sociological study of embodiment in sport and exercise. It offers one way to convey the ‘essences’, corporeal immediacy and textured sensuosity of the lived sporting body. The use of Interpretative Phenomenological Analysis (IPA) is also critically addressed. Key words: phenomenology; existentialist phenomenology; interpretative phenomenological analysis (IPA); sporting embodiment; the lived-body; Merleau-Pont

Membrane protein sequestering by ionic protein–lipid interactions.

Neuronal exocytosis is catalyzed by the SNARE protein syntaxin-1A(1). Syntaxin-1A is clustered in the plasma membrane at sites where synaptic vesicles undergo exocytosis(2,3). However, how syntaxin-1A is sequestered is unknown. Here, we show that syntaxin clustering is mediated by electrostatic interactions with the strongly anionic lipid phosphatidylinositol-4,5-bisphosphate (PIP2). We found with super-resolution STED microscopy on the plasma membrane of PC12 cells that PIP2 is the dominant inner-leaflet lipid in ~73 nm-sized microdomains. This high accumulation of PIP2 was required for syntaxin-1A sequestering, as destruction of PIP2 by the phosphatase synaptojanin-1 reduced syntaxin-1A clustering. Furthermore, co-reconstitution of PIP2 and the C-terminal part of syntaxin-1A in artificial giant unilamellar vesicles resulted in segregation of PIP2 and syntaxin-1A into distinct domains even when cholesterol was absent. Our results demonstrate that electrostatic protein-lipid interactions can result in the formation of microdomains independent of cholesterol or lipid phases

The experience of living with knee osteoarthritis: exploring illness and treatment beliefs through thematic analysis

Purpose: Knee osteoarthritis (OA) is a major cause of disability in older adults. However, there is limited research on the daily experience of living with knee OA. We aimed to offer insight into the beliefs of patients with knee OA about their illness and treatment. Method: Twenty-four semi-structured interviews were conducted with 17 women and 7 men with physician-diagnosed knee OA, aged between 48 and 84 years (mean 1/4 62, SD 1/4 7). The audio-taped interviews lasted from 30 min to 1 h, and were transcribed verbatim. The data were subjected to thematic analysis. The transcripts were independently coded by two researchers to increase reliability of coding. Results: Six themes were developed and two of these are examined in further detail: (i) Illness representation and (ii) Beliefs about the medical and surgical control of pain. Illness representation comprised beliefs about people’s understanding of OA and their pain experience, as well as expectations about the course of illness. The second theme presented experiences of limited pain relief and concerns about the use of drugs and surgery. Conclusion: Exploring illness representations and beliefs about medical and surgical control of pain may provide the basis for initiating psychological interventions for people with knee OA