663 research outputs found

    The influence of simulated exploitation onPatella vulgatapopulations: protandric sex change is size-dependent

    Get PDF
    Grazing mollusks are used as a food resource worldwide, and limpets are harvested commercially for both local consumption and export in several countries. This study describes a field experiment to assess the effects of simulated human exploitation of limpets Patella vulgata on their population ecology in terms of protandry (age-related sex change from male to female), growth, recruitment, migration, and density regulation. Limpet populations at two locations in southwest England were artificially exploited by systematic removal of the largest individuals for 18 months in plots assigned to three treatments at each site: no (control), low, and high exploitation. The shell size at sex change (L50: the size at which there is a 50:50 sex ratio) decreased in response to the exploitation treatments, as did the mean shell size of sexual stages. Size-dependent sex change was indicated by L50 occurring at smaller sizes in treatments than controls, suggesting an earlier switch to females. Mean shell size of P. vulgata neuters changed little under different levels of exploitation, while males and females both decreased markedly in size with exploitation. No differences were detected in the relative abundances of sexual stages, indicating some compensation for the removal of the bigger individuals via recruitment and sex change as no migratory patterns were detected between treatments. At the end of the experiment, 0–15 mm recruits were more abundant at one of the locations but no differences were detected between treatments. We conclude that sex change in P. vulgata can be induced at smaller sizes by reductions in density of the largest individuals reducing interage class competition. Knowledge of sex-change adaptation in exploited limpet populations should underpin strategies to counteract population decline and improve rocky shore conservation and resource management

    Examining the roles of working memory and visual attention in multiple object tracking expertise.

    Get PDF
    This is the final version. Available from the publisher via the DOI in this record.When tracking multiple moving targets among visually similar distractors, human observers are capable of distributing attention over several spatial locations. It is unclear, however, whether capacity limitations or perceptual-cognitive abilities are responsible for the development of expertise in multiple object tracking. Across two experiments, we examined the role of working memory and visual attention in tracking expertise. In Experiment 1, individuals who regularly engaged in object tracking sports (soccer and rugby) displayed improved tracking performance, relative to non-tracking sports (swimming, rowing, running) (p = 0.02, ηp2 = 0.163), but no differences in gaze strategy (ps > 0.31). In Experiment 2, participants trained on an adaptive object tracking task showed improved tracking performance (p = 0.005, d = 0.817), but no changes in gaze strategy (ps > 0.07). They did, however, show significant improvement in a working memory transfer task (p < 0.001, d = 0.970). These findings indicate that the development of tracking expertise is more closely linked to processing capacity limits than perceptual-cognitive strategies

    A content analysis of thinspiration, fitspiration, and bonespiration imagery on social media

    Get PDF
    Background On social media, images such as thinspiration, fitspiration, and bonespiration, are shared to inspire certain body ideals. Previous research has demonstrated that exposure to these groups of content is associated with increased body dissatisfaction and decreased self-esteem. It is therefore important that the bodies featured within these groups of content are more fully understood so that effective interventions and preventative measures can be informed, developed, and implemented. Method A content analysis was conducted on a sample of body-focussed images with the hashtags thinspiration, fitspiration, and bonespiration from three social media platforms. Results The analyses showed that thinspiration and bonespiration content contained more thin and objectified bodies, compared to fitspiration which featured a greater prevalence of muscles and muscular bodies. In addition, bonespiration content contained more bone protrusions and fewer muscles than thinspiration content. Conclusions The findings suggest fitspiration may be a less unhealthy type of content; however, a subgroup of imagery was identified which idealised the extremely thin body type and as such this content should also be approached with caution. Future research should utilise qualitative methods to further develop understandings of the body ideals that are constructed within these groups of content and the motivations behind posting this content

    Cell Cycle Regulation and Cytoskeletal Remodelling Are Critical Processes in the Nutritional Programming of Embryonic Development

    Get PDF
    Many mechanisms purport to explain how nutritional signals during early development are manifested as disease in the adult offspring. While these describe processes leading from nutritional insult to development of the actual pathology, the initial underlying cause of the programming effect remains elusive. To establish the primary drivers of programming, this study aimed to capture embryonic gene and protein changes in the whole embryo at the time of nutritional insult rather than downstream phenotypic effects. By using a cross-over design of two well established models of maternal protein and iron restriction we aimed to identify putative common “gatekeepers” which may drive nutritional programming

    Lean manufacturing, culture and their role on sustainability: A case study in the Chinese automotive industry

    Get PDF
    This paper focuses on lean manufacturing and culture and how they influence the sustainability initiatives of an Automotive company in China. The principle of lean manufacturing is widely applied in the automotive industry worldwide. The last few decades have witnessed the accelerating pace of China’s continued emergence as a major industrial power. With the globalisation of multinational corporations and the development of domestic automotive enterprises, there is an increasing number of cross-cultural motor manufacturing companies starting their business in China. In these companies, cultural diversity is an important factor that affects the management strategies. Using a case study approach, this paper shows the relevant themes on the role of lean manufacturing and culture on the sustainability initiatives taken by the company

    Anhydrobiosis and Freezing-Tolerance:Adaptations That Facilitate the Establishment of Panagrolaimus Nematodes in Polar Habitats

    Get PDF
    <div><p>Anhydrobiotic animals can survive the loss of both free and bound water from their cells. While in this state they are also resistant to freezing. This physiology adapts anhydrobiotes to harsh environments and it aids their dispersal. <i>Panagrolaimus davidi</i>, a bacterial feeding anhydrobiotic nematode isolated from Ross Island Antarctica, can survive intracellular ice formation when fully hydrated. A capacity to survive freezing while fully hydrated has also been observed in some other Antarctic nematodes. We experimentally determined the anhydrobiotic and freezing-tolerance phenotypes of 24 <i>Panagrolaimus</i> strains from tropical, temperate, continental and polar habitats and we analysed their phylogenetic relationships. We found that several other <i>Panagrolaimus</i> isolates can also survive freezing when fully hydrated and that tissue extracts from these freezing-tolerant nematodes can inhibit the growth of ice crystals. We show that <i>P. davidi</i> belongs to a clade of anhydrobiotic and freezing-tolerant panagrolaimids containing strains from temperate and continental regions and that <i>P. superbus</i>, an early colonizer at Surtsey island, Iceland after its volcanic formation, is closely related to a species from Pennsylvania, USA. Ancestral state reconstructions show that anhydrobiosis evolved deep in the phylogeny of <i>Panagrolaimus</i>. The early-diverging <i>Panagrolaimus</i> lineages are strongly anhydrobiotic but weakly freezing-tolerant, suggesting that freezing tolerance is most likely a derived trait. The common ancestors of the <i>davidi</i> and the <i>superbus</i> clades were anhydrobiotic and also possessed robust freezing tolerance, along with a capacity to inhibit the growth and recrystallization of ice crystals. Unlike other endemic Antarctic nematodes, the life history traits of <i>P. davidi</i> do not show evidence of an evolved response to polar conditions. Thus we suggest that the colonization of Antarctica by <i>P. davidi</i> and of Surtsey by <i>P. superbus</i> may be examples of recent “ecological fitting” of freezing-tolerant anhydrobiotic propagules to the respective abiotic conditions in Ross Island and Surtsey.</p></div

    Barriers to primary care responsiveness to poverty as a risk factor for health

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Poverty is widely recognized as a major determinant of poor health, and this link has been extensively studied and verified. Despite the strong evidentiary link, little work has been done to determine what primary care health providers can do to address their patients' income as a risk to their health. This qualitative study explores the barriers to primary care responsiveness to poverty as a health issue in a well-resourced jurisdiction with near-universal health care insurance coverage.</p> <p>Methods</p> <p>One to one interviews were conducted with twelve experts on poverty and health in primary care in Ontario, Canada. Participants included family physicians, specialist physicians, nurse practitioners, community workers, advocates, policy experts and researchers. The interviews were analysed for anticipated and emergent themes.</p> <p>Results</p> <p>This study reveals provider- and patient-centred structural, attitudinal, and knowledge-based barriers to addressing poverty as a risk to health. While many of its findings reinforce previous work in this area, this study's findings point to a number of areas front line primary care providers could target to address their patients' poverty. These include a lack of provider understanding of the lived reality of poverty, leading to a failure to collect adequate data about patients' social circumstances, and to the development of inappropriate care plans. Participants also pointed to prejudicial attitudes among providers, a failure of primary care disciplines to incorporate approaches to poverty as a standard of care, and a lack of knowledge of concrete steps providers can take to address patients' poverty.</p> <p>Conclusions</p> <p>While this study reinforces, in a well-resourced jurisdiction such as Ontario, the previously reported existence of significant barriers to addressing income as a health issue within primary care, the findings point to the possibility of front line primary care providers taking direct steps to address the health risks posed by poverty. The consistent direction and replicability of these findings point to a refocusing of the research agenda toward an examination of interventions to decrease the health impacts of poverty.</p
    corecore