176 research outputs found

    Awareness, use, and perceptions of biodiesel: A comparison of consumers in Belgium and the United States

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    Belgian (N = 61) and American (N = 134) fuel consumers were interviewed in the summer of 2012 to determine their awareness, use, and perceptions of biodiesel. Consumers who were aware of biodiesel were asked their perceptions. A significantly P \u3c 0.0001) higher percentage of Belgian consumers (78.7%) reported owning or driving a diesel vehicle compared to American consumers (9.0%). Belgian and American consumers moderately agreed biodiesel is a high-quality fuel. For both Belgian and American consumers, there was no significant association between owning a diesel vehicle and being aware of biodiesel or having purchased biodiesel. Although Belgian and American consumers agreed that using non-food crops for biodiesel is justified, Belgians were significantly less supportive than American consumers of using food crops for biodiesel. Both Belgian and American consumers disagreed with the statement “I would never use biodiesel”, and the two sets of consumers moderately disagreed that diesel engines would not run properly on biodiesel. Belgian and American consumers agreed that global warming is increasing; however, American consumers were more positive about the potential of biodiesel to reduce harmful exhaust emissions and global warming. Belgian consumers moderately agreed and American consumers agreed that biodiesel is better to use because it is made from renewable resources. Belgian and American consumers generally show similar perceptions of biodiesel, with the exception that American consumers were more positive toward the environmental and renewable aspects of biodiesel use. Recommendations for further research include gaining a better understanding of the potential positive influences that impact consumers’ perceptions of biodiesel

    Ecophysiology of coral reef primary producers across an upwelling gradient in the tropical central Pacific

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    © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Johnson, M. D., Fox, M. D., Kelly, E. L. A., Zgliczynski, B. J., Sandin, S. A., & Smith, J. E. Ecophysiology of coral reef primary producers across an upwelling gradient in the tropical central Pacific. Plos One, 15(2), (2020): e0228448, doi:10.1371/journal.pone.0228448.Upwelling is an important source of inorganic nutrients in marine systems, yet little is known about how gradients in upwelling affect primary producers on coral reefs. The Southern Line Islands span a natural gradient of inorganic nutrient concentrations across the equatorial upwelling region in the central Pacific. We used this gradient to test the hypothesis that benthic autotroph ecophysiology is enhanced on nutrient-enriched reefs. We measured metabolism and photophysiology of common benthic taxa, including the algae Porolithon, Avrainvillea, and Halimeda, and the corals Pocillopora and Montipora. We found that temperature (27.2–28.7°C) was inversely related to dissolved inorganic nitrogen (0.46–4.63 ÎŒM) and surface chlorophyll a concentrations (0.108–0.147 mg m-3), which increased near the equator. Contrary to our prediction, ecophysiology did not consistently track these patterns in all taxa. Though metabolic rates were generally variable, Porolithon and Avrainvillea photosynthesis was highest at the most productive and equatorial island (northernmost). Porolithon photosynthetic rates also generally increased with proximity to the equator. Photophysiology (maximum quantum yield) increased near the equator and was highest at northern islands in all taxa. Photosynthetic pigments also were variable, but chlorophyll a and carotenoids in Avrainvillea and Montipora were highest at the northern islands. Phycobilin pigments of Porolithon responded most consistently across the upwelling gradient, with higher phycoerythrin concentrations closer to the equator. Our findings demonstrate that the effects of in situ nutrient enrichment on benthic autotrophs may be more complex than laboratory experiments indicate. While upwelling is an important feature in some reef ecosystems, ancillary factors may regulate the associated consequences of nutrient enrichment on benthic reef organisms.This work was supported by funding from the Moore Family Foundation, the Gordon and Betty Moore Foundation, the Scripps family, and anonymous donors. The funders had no role in study design, data collection and analysis, or preparation of the manuscript

    Treading carefully: a qualitative ethnographic study of the clinical, social and educational uses of exercise ECG in evaluating stable chest pain

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    Objective To examine functions of the exercise ECG in the light of the recent National Institute for Health and Clinical Excellence guidelines recommending that it should not be used for the diagnosis or exclusion of stable angina. Design Qualitative ethnographic study based on interviews and observations of clinical practice. Setting 3 rapid access chest pain clinics in England. Participants Observation of 89 consultations in chest pain clinics, 18 patient interviews and 12 clinician interviews. Main outcome measure Accounts and observations of consultations in chest pain clinics. Results The exercise ECG was observed to have functions that extended beyond diagnosis. It was used to clarify a patient's story and revise the initial account. The act of walking on the treadmill created an additional opportunity for dialogue between clinician and patient and engagement of the patient in the diagnostic process through precipitation of symptoms and further elaboration of symptoms. The exercise ECG facilitated reassurance in relation to exercise capacity and tolerance, providing a platform for behavioural advice particularly when exercise was promoted by the clinician. Conclusions Many of the practices that have been built up around the use of the exercise ECG are potentially beneficial to patients and need to be considered in the re-design of services without that test. Through its contribution to the patient's history and to subsequent advice to the patient, the exercise ECG continues to inform the specialist assessment and management of patients with new onset stable chest pain, beyond its now marginalised role in diagnosis

    Disturbances in primary visual processing as a function of healthy aging

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    For decades, visual entrainment paradigms have been widely used to investigate basic visual processing in healthy individuals and those with neurological disorders. While healthy aging is known to be associated with alterations in visual processing, whether this extends to visual entrainment responses and the precise cortical regions involved is not fully understood. Such knowledge is imperative given the recent surge in interest surrounding the use of flicker stimulation and entrainment in the context of identifying and treating Alzheimer’s disease (AD). In the current study, we examined visual entrainment in eighty healthy aging adults using magnetoencephalography (MEG) and a 15 Hz entrainment paradigm, while controlling for age-related cortical thinning. MEG data were imaged using a time-frequency resolved beamformer and peak voxel time series were extracted to quantify the oscillatory dynamics underlying the processing of the visual flicker stimuli. We found that, as age increased, the mean amplitude of entrainment responses decreased and the latency of these responses increased. However, there was no effect of age on the trial-to-trial consistency in phase (i.e., inter-trial phase locking) nor amplitude (i.e., coefficient of variation) of these visual responses. Importantly, we discovered that the relationship between age and response amplitude was fully mediated by the latency of visual processing. These results indicate that aging is associated with robust changes in the latency and amplitude of visual entrainment responses within regions surrounding the calcarine fissure, which should be considered in studies examining neurological disorders such as AD and other conditions associated with increased age

    Rapid ecosystem-scale consequences of acute deoxygenation on a Caribbean coral reef

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    Loss of oxygen in the global ocean is accelerating due to climate change and eutrophication, but how acute deoxygenation events affect tropical marine ecosystems remains poorly understood. Here we integrate analyses of coral reef benthic communities with microbial community sequencing to show how a deoxygenation event rapidly altered benthic community composition and microbial assemblages in a shallow tropical reef ecosystem. Conditions associated with the event precipitated coral bleaching and mass mortality, causing a 50% loss of live coral and a shift in the benthic community that persisted a year later. Conversely, the unique taxonomic and functional profile of hypoxia-associated microbes rapidly reverted to a normoxic assemblage one month after the event. The decoupling of ecological trajectories among these major functional groups following an acute event emphasizes the need to incorporate deoxygenation as an emerging stressor into coral reef research and management plans to combat escalating threats to reef persistence

    Gradients in primary production predict trophic strategies of mixotrophic corals across spatial scales

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    Mixotrophy is among the most successful nutritional strategies in terrestrial and marine ecosystems. The ability of organisms to supplement primary nutritional modes along continua of autotrophy and heterotrophy fosters trophic flexibility that can sustain metabolic demands under variable or stressful conditions. Symbiotic, reef-building corals are among the most broadly distributed and ecologically important mixotrophs, yet we lack a basic understanding of how they modify their use of autotrophy and heterotrophy across gradients of food availability. Here, we evaluate how one coral species, Pocillopora meandrina, supplements autotrophic nutrition through heterotrophy within an archipelago and test whether this pattern holds across species globally. Using stable isotope analysis (delta C-13) and satellite-derived estimates of nearshore primary production (chlorophylla, as a proxy for food availability), we show that P. meandrina incorporates a greater proportion of carbon via heterotrophy when more food is available across five central Pacific islands. We then show that this pattern is consistent globally using data from 15 coral species across 16 locations spanning the Caribbean Sea and the Indian and Pacific Oceans. Globally, surface chlorophyll-a explains 77% of the variation in coral heterotrophic nutrition, 86% for one genus across 10 islands, and 94% when controlling for coral taxonomy within archipelagos. These results demonstrate, for the first time, that satellite-derived estimates of nearshore primary production provide a globally relevant proxy for resource availability that can explain variation in coral trophic ecology. Thus, our model provides a pivotal step toward resolving the biophysical couplings between mixotrophic organisms and spatial patterns of resource availability in the coastal oceans

    Climate warming erodes tropical reef habitat through frequency and intensity of episodic hypoxia

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    Climate warming threatens marine life by increasing metabolic oxygen demand while decreasing oxygen availability. Tropical species living in warm, low oxygen environments may be most at risk, but their tolerances and exposures to these stressors remain poorly documented. We evaluated habitat restrictions for two brittle star species from Caribbean coral reefs by integrating field observations, laboratory experiments and an ecophysiological model. The absence of one species from the warmest reefs results from vital activity restrictions during episodic low oxygen extremes, even though average conditions are well within physiological tolerance limits. Over the past decade, warmer temperatures have been significantly correlated with a greater frequency and intensity of hypoxic events. Continued warming will progressively exclude hypoxia-tolerant species, even if average oxygen remains constant. A warming-driven increase in frequency or intensity of low oxygen extremes could similarly accelerate habitat loss across other marine ecosystems. -- Keywords : Oxygen ; Aquatic hypoxia ; Hypoxia ; Coral reefs ; Oxygen metabolism ; Ocean temperature ; Echinoderms ; Climate change
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