3,240 research outputs found

    Tropical fish recruitment success varies among temperate reef habitats, potentially impacting their range expansion

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    University of Technology, Sydney. Faculty of Science.Climate change is leading to poleward range expansions of tropical fishes. But to shift poleward with warming waters, species need habitats at higher latitudes with suitable abiotic conditions, resources and communities. This thesis provides the initial empirical evidence that recruitment success of tropical reef fishes varies considerably among temperate reef habitats, encountered at forefronts of their range expansion. Global Positioning System (GPS) - tracked roaming surveys were firstly established as a preferable method for quantifying these rare and sparsely distributed range-expanding fishes, offering reliable density estimates, maximised sightings and improved efficiency compared to traditional belt transects (Chapter 2). GPS-tracked roaming surveys were then conducted in two hotspots of warming, southeastern Australia and western Japan, revealing that spatial variance in biogenic structure and wave regime between reefs may strongly organise, and even limit where tropical fishes recruit (Chapters 3 and 4). Shelter was a key limiting factor, with embayed reefs supporting greater richness, diversity and densities of new recruit and early juvenile tropical fishes than adjacent wave-exposed reefs (Chapter 3). Both habitat generalists (e.g., planktivores, herbivores and omnivores) and specialists (i.e., obligate coral feeders) were more abundant and diverse on embayed reefs. Factors structuring higher recruitment of tropical fishes on embayed reefs were the greater shelter from wave action and branching coral cover (coral-obligate habitat users only). On finer spatial scales, greater densities, diversity and species richness of tropical fish recruits associated with non-macroalgal than macroalgal reef (Chapter 4). Aquarium experiments indicated that non-macroalgal reef (no branching algae) were preferred temperate settlement habitat for tropical fish larvae. However, the abundance and composition of native predator communities impacted feeding activities of a tropical damselfish (Abudefduf vaigiensis; Chapter 5), suggesting that even if suitably structured reefs are available for recruiting tropical fishes, temperate predators may constrain their survival by limiting food intake. Feeding activities of A. vaigiensis were reduced in presence of a high predation threat, both in situ and in an aquarium experiment. Such predator-driven reductions in feeding were accentuated in summer, but diminished in cool winter waters, when poor metabolic performance of this warm-adapted species lowered their feeding activities independent of predation threat. This thesis shows that temperate reef structure and predator densities, and human modification of these factors, need to be considered along with dispersal factors and water temperature to accurately predict geographic responses of many tropical fishes to climate change and impacts of this redistribution on temperate marine ecosystems

    Extended Reaction Rate Integral as Solutions of Some General Differential Equations

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    Here an extended form of the reaction rate probability integral, in the case of nonresonant thermonuclear reactions with the depleted tail and the right tail cut off, is considered. The reaction rate integral then can be looked upon as the inverse of the convolution of the Mellin transforms of Tsallis type statistics of nonextensive statistical mechanics and stretched exponential as well as that of superstatistics and stretched exponentials. The differential equations satisfied by the extended probability integrals are derived. The idea used is a novel one of evaluating the extended integrals in terms of some special functions and then by invoking the differential equations satisfied by these special functions. Some special cases of limiting situations are also discussed.Comment: 9 pages, LaTe

    Wave-sheltered embayments are recruitment hotspots for tropical fishes on temperate reefs

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    Š Inter-Research 2016. Poleward redistribution of species, facilitated by global warming, will be compromised if habitats at higher latitudes do not support the species' early life stages. For tropical reef fishes, reef structure may mediate colonisation of temperate regions; however, an understanding of key habitat requirements for colonisation is currently lacking. We show that density, diversity (taxonomic and trophic) and species richness of newly recruited tropical reef fishes were greater in embayed than exposed reefs in 2 mid-latitude temperate zones, where coastal waters are rapidly warming: southeastern Australia (30.5-33° S) and western Japan (32-33.5° N). Dietary generalists (e.g. planktivores and herbivores) and specialists (corallivores) associated more commonly with embayed reefs. Wave exposure was a stronger predictor of the density and richness of dietary generalists than water temperature, latitude, predatory fish densities, reef rugosities, benthos and distance to river mouths. Corallivores were strongly associated with branching corals, which were exclusive to highly sheltered reefs. We also explored habitat associations of 7 focal species within a coral reef, One Tree Island (OTI), Great Barrier Reef. Four species associated with wave - sheltered over exposed reef on OTI and temperate Australian reef. However, Abudefduf vaigiensis, Pomacentrus coelestis and Acanthurus triostegus associated more with wave-sheltered reef in temperate regions. We hypothesise that cool temperate waters promote greater sheltering of some warm-adapted, tropical fishes by impacting their swimming/physiological performance. Results suggest availability of embayed temperate reefs may influence where some tropical fishes colonise with warming waters, through impacting recruitment. Wave exposure of reefs should be considered when predicting geographic responses of tropical fishes to climate change

    Sediment pollution impacts sensory ability and performance of settling coral-reef fish

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    © 2015, Springer-Verlag Berlin Heidelberg. Marine organisms are under threat globally from a suite of anthropogenic sources, but the current emphasis on global climate change has deflected the focus from local impacts. While the effect of increased sedimentation on the settlement of coral species is well studied, little is known about the impact on larval fish. Here, the effect of a laterite “red soil” sediment pollutant on settlement behaviour and post-settlement performance of reef fish was tested. In aquarium tests that isolated sensory cues, we found significant olfaction-based avoidance behaviour and disruption of visual cue use in settlement-stage larval fish at 50 mg L−1, a concentration regularly exceeded in situ during rain events. In situ light trap catches showed lower abundance and species richness in the presence of red soil, but were not significantly different due to high variance in the data. Prolonged exposure to red soil produced altered olfactory cue responses, whereby fish in red soil made a likely maladaptive choice for dead coral compared to controls where fish chose live coral. Other significant effects of prolonged exposure included decreased feeding rates and body condition. These effects on fish larvae reared over 5 days occurred in the presence of a minor drop in pH and may be due to the chemical influence of the sediment. Our results show that sediment pollution of coral reefs may have more complex effects on the ability of larval fish to successfully locate suitable habitat than previously thought, as well as impacting on their post-settlement performance and, ultimately, recruitment success

    Improving the use of research evidence in guideline development: 1. Guidelines for guidelines

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    BACKGROUND: The World Health Organization (WHO), like many other organisations around the world, has recognised the need to use more rigorous processes to ensure that health care recommendations are informed by the best available research evidence. This is the first of a series of 16 reviews that have been prepared as background for advice from the WHO Advisory Committee on Health Research to WHO on how to achieve this. OBJECTIVES: We reviewed the literature on guidelines for the development of guidelines. METHODS: We searched PubMed and three databases of methodological studies for existing systematic reviews and relevant methodological research. We did not conduct systematic reviews ourselves. Our conclusions are based on the available evidence, consideration of what WHO and other organisations are doing and logical arguments. KEY QUESTIONS AND ANSWERS: We found no experimental research that compared different formats of guidelines for guidelines or studies that compared different components of guidelines for guidelines. However, there are many examples, surveys and other observational studies that compared the impact of different guideline development documents on guideline quality. WHAT HAVE OTHER ORGANIZATIONS DONE TO DEVELOP GUIDELINES FOR GUIDELINES FROM WHICH WHO CAN LEARN? • Establish a credible, independent committee that evaluates existing methods for developing guidelines or that updates existing ones. • Obtain feedback and approval from various stakeholders during the development process of guidelines for guidelines. • Develop a detailed source document (manual) that guideline developers can use as reference material. WHAT SHOULD BE THE KEY COMPONENTS OF WHO GUIDELINES FOR GUIDELINES? • Guidelines for guidelines should include information and instructions about the following components: 1) Priority setting; 2) Group composition and consultations; 3) Declaration and avoidance of conflicts of interest; 4) Group processes; 5) Identification of important outcomes; 6) Explicit definition of the questions and eligibility criteria ; 7) Type of study designs for different questions; 8) Identification of evidence; 9) Synthesis and presentation of evidence; 10) Specification and integration of values; 11) Making judgments about desirable and undesirable effects; 12) Taking account of equity; 13) Grading evidence and recommendations; 14) Taking account of costs; 15) Adaptation, applicability, transferability of guidelines; 16) Structure of reports; 17) Methods of peer review; 18) Planned methods of dissemination & implementation; 19) Evaluation of the guidelines. WHAT HAVE OTHER ORGANIZATIONS DONE TO IMPLEMENT GUIDELINES FOR GUIDELINES FROM WHICH WHO CAN LEARN? • Obtain buy-in from regions and country level representatives for guidelines for guidelines before dissemination of a revised version. • Disseminate the guidelines for guidelines widely and make them available (e.g. on the Internet). • Develop examples of guidelines that guideline developers can use as models when applying the guidelines for guidelines. • Ensure training sessions for those responsible for developing guidelines. • Continue to monitor the methodological literature on guideline development

    Theoretical Models of Sunspot Structure and Dynamics

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    Recent progress in theoretical modeling of a sunspot is reviewed. The observed properties of umbral dots are well reproduced by realistic simulations of magnetoconvection in a vertical, monolithic magnetic field. To understand the penumbra, it is useful to distinguish between the inner penumbra, dominated by bright filaments containing slender dark cores, and the outer penumbra, made up of dark and bright filaments of comparable width with corresponding magnetic fields differing in inclination by some 30 degrees and strong Evershed flows in the dark filaments along nearly horizontal or downward-plunging magnetic fields. The role of magnetic flux pumping in submerging magnetic flux in the outer penumbra is examined through numerical experiments, and different geometric models of the penumbral magnetic field are discussed in the light of high-resolution observations. Recent, realistic numerical MHD simulations of an entire sunspot have succeeded in reproducing the salient features of the convective pattern in the umbra and the inner penumbra. The siphon-flow mechanism still provides the best explanation of the Evershed flow, particularly in the outer penumbra where it often consists of cool, supersonic downflows.Comment: To appear in "Magnetic Coupling between the Interior and the Atmosphere of the Sun", eds. S.S. Hasan and R.J. Rutten, Astrophysics and Space Science Proceedings, Springer-Verlag, Heidelberg, Berlin, 200

    Salience-based selection: attentional capture by distractors less salient than the target

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    Current accounts of attentional capture predict the most salient stimulus to be invariably selected first. However, existing salience and visual search models assume noise in the map computation or selection process. Consequently, they predict the first selection to be stochastically dependent on salience, implying that attention could even be captured first by the second most salient (instead of the most salient) stimulus in the field. Yet, capture by less salient distractors has not been reported and salience-based selection accounts claim that the distractor has to be more salient in order to capture attention. We tested this prediction using an empirical and modeling approach of the visual search distractor paradigm. For the empirical part, we manipulated salience of target and distractor parametrically and measured reaction time interference when a distractor was present compared to absent. Reaction time interference was strongly correlated with distractor salience relative to the target. Moreover, even distractors less salient than the target captured attention, as measured by reaction time interference and oculomotor capture. In the modeling part, we simulated first selection in the distractor paradigm using behavioral measures of salience and considering the time course of selection including noise. We were able to replicate the result pattern we obtained in the empirical part. We conclude that each salience value follows a specific selection time distribution and attentional capture occurs when the selection time distributions of target and distractor overlap. Hence, selection is stochastic in nature and attentional capture occurs with a certain probability depending on relative salience

    Lived Experience of Caregivers of Family-Centered Care in the Neonatal Intensive Care Unit: “Evocation of Being at Home

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    Background: In recent decades, family-centered care (FCC) has come to be known, accepted, and reported as the best care strategy for admitted children and their families. However, in spite of the increasing application of this approach, the experiences of the caregivers have not yet been studied. Objectives: The present study aimed at the description and interpretation of the FCC experience in two neonatal intensive care units (NICU) at Shiraz University of Medical Sciences. Methods: This study was conducted through the hermeneutic phenomenological approach. Semi-structured interviews were conducted with 17 professional and familial caregivers, and their interactions were observed in three work shifts. The interviews were audiotaped and transcribed verbatim. After observations, field notes were also written. Finally, the data were analyzed through van Manen’s methodology. Results: One of the essential themes that emerged in this study was the “evocation of being at home” among familial and even professional caregivers. This theme had three subthemes: i.e., “meta-family interaction,” “comprehensive support,” and “reconstruction of a normal family.” Accordingly, FCC eliminated borders between professional and non-professional caregivers and built close relationships among them in the NICU. It also provided for the needs of neonates, their families, and even professional caregivers through perceived and received support. Conclusions: Parents of the neonates admitted to the NICU experience hard moments. They not only play the role of primary caregivers, but they also receive the care. Focusing on the different meanings of this care from the caregivers’ points of view and having managers provide certain requirements can guarantee the establishment of comprehensive care for clients and proper support for the staff in this uni

    Phenoloxidase activity acts as a mosquito innate immune response against infection with semliki forest virus

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    Several components of the mosquito immune system including the RNA interference (RNAi), JAK/STAT, Toll and IMD pathways have previously been implicated in controlling arbovirus infections. In contrast, the role of the phenoloxidase (PO) cascade in mosquito antiviral immunity is unknown. Here we show that conditioned medium from the Aedes albopictus-derived U4.4 cell line contains a functional PO cascade, which is activated by the bacterium Escherichia coli and the arbovirus Semliki Forest virus (SFV) (Togaviridae; Alphavirus). Production of recombinant SFV expressing the PO cascade inhibitor Egf1.0 blocked PO activity in U4.4 cell- conditioned medium, which resulted in enhanced spread of SFV. Infection of adult female Aedes aegypti by feeding mosquitoes a bloodmeal containing Egf1.0-expressing SFV increased virus replication and mosquito mortality. Collectively, these results suggest the PO cascade of mosquitoes plays an important role in immune defence against arboviruses
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