7,259 research outputs found

    Seabird nutrient subsidies alter patterns of algal abundance and fish biomass on coral reefs following a bleaching event

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    Cross-ecosystem nutrient subsidies play a key role in the structure and dynamics of recipient communities, but human activities are disrupting these links. Because nutrient subsidies may also enhance community stability, the effects of losing these inputs may be exacerbated in the face of increasing climate-related disturbances. Nutrients from seabirds nesting on oceanic islands enhance the productivity and functioning of adjacent coral reefs, but it is unknown whether these subsidies affect the response of coral reefs to mass bleaching events or whether the benefits of these nutrients persist following bleaching. To answer these questions, we surveyed benthic organisms and fishes around islands with seabirds and nearby islands without seabirds due to the presence of invasive rats. Surveys were conducted in the Chagos Archipelago, Indian Ocean, immediately before the 2015–2016 mass bleaching event and, in 2018, two years following the bleaching event. Regardless of the presence of seabirds, relative coral cover declined by 32%. However, there was a post-bleaching shift in benthic community structure around islands with seabirds, which did not occur around islands with invasive rats, characterized by increases in two types of calcareous algae (crustose coralline algae [CCA] and Halimeda spp.). All feeding groups of fishes were positively affected by seabirds, but only herbivores and piscivores were unaffected by the bleaching event and sustained the greatest difference in biomass between islands with seabirds versus those with invasive rats. By contrast, corallivores and planktivores, both of which are coral-dependent, experienced the greatest losses following bleaching. Even though seabird nutrients did not enhance community-wide resistance to bleaching, they may still promote recovery of these reefs through their positive influence on CCA and herbivorous fishes. More broadly, the maintenance of nutrient subsidies, via strategies including eradication of invasive predators, may be important in shaping the response of ecological communities to global climate change

    Boom and bust of keystone structure on coral reefs

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    Repeated bouts of coral bleaching threaten the long-term persistence of coral reefs and associated communities. Here, we document the short- and long-term impacts of heatwave events on coral and fish assemblages, based on regular surveys of 18 reefs of the granitic islands of Seychelles over 23 yr. Extreme heat events in 1998 and 2016 led to bleaching-associated declines in coral cover, whilst between these years there was an interim period of coral recovery on some reefs. Coral decline and recovery were primarily due to changes in the cover of branching coral, particularly those from the families Acroporidae and Pocilloporidae. Surveys during the 2016 bleaching found that 95% of the 468 Acropora and Pocillopora colonies observed were either bleached or recently dead. The extent of bleaching and subsequent mortality were best explained by a priori assessments of community susceptibility to heat stress. One year later (2017), coral cover had fallen by 70% and average coverage across the 18 reefs was at 6%, similar to levels recorded in 2005, 7 yr after the 1998 bleaching. Decline in coral following the 2016 bleaching coincided with reduced abundance of fish < 11 cm TL, particularly corallivores, invertivores and mixed diet feeders. These changes are likely to foreshadow more widespread loss once the habitat structure erodes. Accordingly, 7 yr after the 1998 bleaching, when coral skeletons and reef structure had collapsed on some reefs, abundance of both large- and small-bodied fish had declined. We show that fluctuation in the cover of branching coral is positively associated with changes in the abundance of small-bodied fish which contribute to ecological processes and high diversity, suggesting branching corals are a keystone structure. Increased frequency of bleaching threatens the capacity of branching corals to fully recover after disturbances, reducing the amplitude of boom bust cycles of these corals and the keystone habitat structure they provide reef fish

    Radio Astronomy

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    Contains reports on four research projects.National Aeronautics and Space Administration (Grant NsG-240-62)National Aeronautics and Space Administration (Grant NsG-419)Lincoln Laboratory (Purchase Order DDL BB-107)U. S. Air Force (Contract AF 19(628)-500)Office of Naval Research (Contract Nonr 3963(02

    Assessing wellbeing at school entry using the strengths and difficulties questionnaire: professional perspectives

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    &lt;p&gt;Background: Emotional and behavioural disorders in early childhood are related to poorer academic attainment and school engagement, and difficulties already evident at the point of starting school can affect a child’s later social and academic development. Successful transfer from pre-school settings to primary education is helped by communication between pre-school staff and primary school teachers. Typically, in Scotland, pre-school establishments prepare individual profiles of children before they start school around the age of five years, highlighting their strengths and development needs, for transfer to primary schools. There is, however, no consistent approach to the identification of potential social, emotional and behavioural problems. In 2010, in one local authority area in Scotland, the Strengths and Difficulties Questionnaire (SDQ) was introduced for children about to start school as a routine, structured, component of the transition process to help teachers plan support arrangements for classes and individual children. The SDQ assesses emotional, conduct, hyperactivity/ inattention and peer-relationship problems as well as pro-social behaviour. In order to be an effective means of communicating social and emotional functioning, the use of instruments such as the SDQ needs to be practicable. Finding out the views of pre-school education staff with experience of assessing children using the SDQ was, therefore, essential to establish its future utility.&lt;/p&gt; &lt;p&gt;Aim: The purpose of this study was to explore the views of pre-school education staff about assessing social and emotional wellbeing of children at school entry using the SDQ. The objectives were to examine the opinions of pre-school workers about completing the SDQ and to elicit their thoughts on the value of doing this and their perceptions of the usefulness of the information collected.&lt;/p&gt; &lt;p&gt;Method: Pre-school establishments were approached using a purposive sampling strategy in order to achieve a mix of local authority (n=14) and ‘partnership’ establishments (n=8) as well as different socio-economic areas. Semi-structured interviews (n=25) were conducted with pre-school head teachers (n=14) and child development officers (n=11) in order to explore the process of completing the SDQ along with perceptions of its value. The interviews were transcribed verbatim and analysed thematically.&lt;/p&gt; &lt;p&gt;Results: In general, staff in pre-school establishments viewed the use of the SDQ positively. It was seen as a chance to highlight the social and emotional development of children rather than just their academic or educational ability. Most felt that the SDQ had not identified anything they did not already know about a child. A minority, nevertheless, suggested that a previously unrecognised potential difficulty was brought to light, most commonly emotional problems. Completing the SDQ was felt to be relatively straightforward even though the staff felt under pressure from competing priorities. Concerns were, however, raised about the potential of labelling a child at an early stage of formal education.&lt;/p&gt; &lt;p&gt;Conclusion: The findings from this small scale study suggest that, from the point of view of pre-school education staff, it is feasible to assess children systematically for social and behavioural problems as part of the routine transition process at school entry.&lt;/p&gt

    Increased prevalence of expiratory flow limitation during exercise in children with bronchopulmonary dysplasia.

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    Evidence regarding the prevalence of expiratory flow limitation (EFL) during exercise and the ventilatory response to exercise in children born preterm is limited. This study aimed to determine the prevalence of EFL as well as contributing factors to EFL and the ventilatory response to exercise in preterm children with and without bronchopulmonary dysplasia (BPD). Preterm children (=32 weeks gestational age) aged 9-12 years with (n=64) and without (n=42) BPD and term controls (n=43), performed an incremental treadmill exercise test with exercise tidal flow-volume loops. More preterm children with BPD (53%) had EFL compared with preterm children without BPD (26%) or term controls (28%) (p&lt;0.05). The presence of EFL was independently associated with decreased forced expiratory volume in 1 s/forced vital capacity z-score and lower gestational age (p&lt;0.05). There was no difference in peak oxygen uptake between preterm children with BPD and term controls (48.0 versus 48.4 mL·kg-1·min-1; p=0.063); however, children with BPD had a lower tidal volume at peak exercise (mean difference -27 mL·kg-1, 95% CI -49-?-5; p&lt;0.05). Children born preterm without BPD had ventilatory responses to exercise similar to term controls. Expiratory flow limitation is more prevalent in children born preterm with BPD and is associated with airway obstruction and a lower gestational age

    Ratiometric sensing of fluoride ions using Raman spectroscopy

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    Ratiometric Raman spectroscopy represents a novel sensing approach for the detection of fluoride anions based on alkyne desilylation chemistry. This method enables rapid, anion selective and highly sensitive detection of fluoride in a simple paper-based assay format using a portable Raman spectrometer

    Mo\u3csup\u3eV\u3c/sup\u3e Electron Paramagnetic Resonance of Sulfite Oxidase Revisited: The Low-pH Chloride Signal

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    Valuable information on the active sites of molybdenum enzymes has been provided by MoV electron paramagnetic resonance (EPR) spectroscopy. In recent years, multiple resonance techniques have been extensively used to examine details of the active-site structure, but basic continuous-wave (CW) EPR has not been re-evaluated in several decades. Here, we present a re-examination of the CW EPR spectroscopy of the sulfite oxidase low-pH chloride species and provide evidence for direct coordination of molybdenum by chloride

    The near-infrared morphology of ultraluminous infrared galaxies

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    Near-infrared images at 1.25 μm, 1.65 μm, and 2.2 μm have been obtained of nine galaxies from the IRAS Bright Galaxy Sample with infrared luminosities L_(IR) ≥ 10^(12) L_☉. Two of the 2.2 μm images reveal previously undetected double nuclei, increasing the number of close double nuclei known for this sample from two to four. For three of these four sources, the colors of both nuclei are substantially different from those of normal spiral galaxies, indicating that the high activity state in high-luminosity mergers tends to occur in both nuclei. Three sources show 2.2 μm emission that is more centrally concentrated than the emission at 1.3 μm, a result that can be explained as the effects of dust emission and/or extinction or, alternatively, as the result of direct emission at 2.2 μm from the accretion disk of a central active galactic nucleus. Implications of these results for the model that galaxy collisions lead to quasar formation are briefly discussed. Finally, from the frequency and separation of the double nucleus sources, the lifetime of the ultraluminous phase of galaxies is estimated to be ~ 4 x 10^8 yr
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