638 research outputs found
Ecological and methodological drivers of species' distribution and phenology responses to climate change
Climate change is shifting species’ distribution and phenology. Ecological traits, such as mobility or reproductive mode, explain variation in observed rates of shift for some taxa. However, estimates of relationships between traits and climate responses could be influenced by how responses are measured. We compiled a global data set of 651 published marine species’ responses to climate change, from 47 papers on distribution shifts and 32 papers on phenology change. We assessed the relative importance of two classes of predictors of the rate of change, ecological traits of the responding taxa and methodological approaches for quantifying biological responses. Methodological differences explained 22% of the variation in range shifts, more than the 7.8% of the variation explained by ecological traits. For phenology change, methodological approaches accounted for 4% of the variation in measurements, whereas 8% of the variation was explained by ecological traits. Our ability to predict responses from traits was hindered by poor representation of species from the tropics, where temperature isotherms are moving most rapidly. Thus, the mean rate of distribution change may be underestimated by this and other global syntheses. Our analyses indicate that methodological approaches should be explicitly considered when designing, analysing and comparing results among studies. To improve climate impact studies, we recommend that (1) reanalyses of existing time series state how the existing data sets may limit the inferences about possible climate responses; (2) qualitative comparisons of species’ responses across different studies be limited to studies with similar methodological approaches; (3) meta-analyses of climate responses include methodological attributes as covariates; and (4) that new time series be designed to include the detection of early warnings of change or ecologically relevant change. Greater consideration of methodological attributes will improve the accuracy of analyses that seek to quantify the role of climate change in species’ distribution and phenology changes
Radiative Transfer for Exoplanet Atmospheres
Remote sensing of the atmospheres of distant worlds motivates a firm
understanding of radiative transfer. In this review, we provide a pedagogical
cookbook that describes the principal ingredients needed to perform a radiative
transfer calculation and predict the spectrum of an exoplanet atmosphere,
including solving the radiative transfer equation, calculating opacities (and
chemistry), iterating for radiative equilibrium (or not), and adapting the
output of the calculations to the astronomical observations. A review of the
state of the art is performed, focusing on selected milestone papers.
Outstanding issues, including the need to understand aerosols or clouds and
elucidating the assumptions and caveats behind inversion methods, are
discussed. A checklist is provided to assist referees/reviewers in their
scrutiny of works involving radiative transfer. A table summarizing the
methodology employed by past studies is provided.Comment: 7 pages, no figures, 1 table. Filled in missing information in
references, main text unchange
A continuum from clear to cloudy hot-Jupiter exoplanets without primordial water depletion
PublishedLetterThousands of transiting exoplanets have been discovered, but spectral analysis of their atmospheres has so far been dominated by a small number of exoplanets and data spanning relatively narrow wavelength ranges (such as 1.1 to 1.7 μm). Recent studies show that some hot- Jupiter exoplanets have much weaker water absorption features in their near-infrared spectra than predicted. The low amplitude of water signatures could be explained by very low water abundances, which may be a sign that water was depleted in the protoplanetary disk at the planet’s formation location, but it is unclear whether this level of depletion can actually occur. Alternatively, these weak signals could be the result of obscuration by clouds or hazes, as found in some optical spectra. Here we report results from a comparative study of ten hot Jupiters covering the wavelength range 0.3–5 micrometres, which allows us to resolve both the optical scattering and infrared molecular absorption spectroscopically. Our results reveal a diverse group of hot Jupiters that exhibit a continuum from clear to cloudy atmospheres. We find that the difference between the planetary radius measured at optical and infrared wavelengths is an effective metric for distinguishing different atmosphere types. The difference correlates with the spectral strength of water, so that strong water absorption lines are seen in clear-atmosphere planets and the weakest features are associated with clouds and hazes. This result strongly suggests that primordial water depletion during formation is unlikely and that clouds and hazes are the cause of weaker spectral signatures.European Research Council European Union’s Seventh Framework Programme (FP7/2007-2013)NASACNES and the French Agence Nationale de la Recherche (ANR)UK Science and Technology Facilities Council (STFC)NSFTennessee State UniversityState of Tennesse
An Anti-Glitch in a Magnetar
Magnetars are neutron stars showing dramatic X-ray and soft -ray
outbursting behaviour that is thought to be powered by intense internal
magnetic fields. Like conventional young neutron stars in the form of radio
pulsars, magnetars exhibit "glitches" during which angular momentum is believed
to be transferred between the solid outer crust and the superfluid component of
the inner crust. Hitherto, the several hundred observed glitches in radio
pulsars and magnetars have involved a sudden spin-up of the star, due
presumably to the interior superfluid rotating faster than the crust. Here we
report on X-ray timing observations of the magnetar 1E 2259+586 which we show
exhibited a clear "anti-glitch" -- a sudden spin down. We show that this event,
like some previous magnetar spin-up glitches, was accompanied by multiple X-ray
radiative changes and a significant spin-down rate change. This event, if of
origin internal to the star, is unpredicted in models of neutron star spin-down
and is suggestive of differential rotation in the neutron star, further
supporting the need for a rethinking of glitch theory for all neutron stars
Strengthening confidence in climate change impact science
Aim: To assess confidence in conclusions about climate-driven biological change through time, and identify approaches for strengthening confidence scientific conclusions about ecological impacts of climate change. Location: Global. Methods: We outlined a framework for strengthening confidence in inferences drawn from biological climate impact studies through the systematic integration of prior expectations, long-term data and quantitative statistical procedures. We then developed a numerical confidence index (Cindex) and used it to evaluate current practices in 208 studies of marine climate impacts comprising 1735 biological time series. Results: Confidence scores for inferred climate impacts varied widely from 1 to 16 (very low to high confidence). Approximately 35% of analyses were not associated with clearly stated prior expectations and 65% of analyses did not test putative non-climate drivers of biological change. Among the highest-scoring studies, 91% tested prior expectations, 86% formulated expectations for alternative drivers but only 63% statistically tested them. Higher confidence scores observed in studies that did not detect a change or tracked multiple species suggest publication bias favouring impact studies that are consistent with climate change. The number of time series showing climate impacts was a poor predictor of average confidence scores for a given group, reinforcing that vote-counting methodology is not appropriate for determining overall confidence in inferences. Main conclusions: Climate impacts research is expected to attribute biological change to climate change with measurable confidence. Studies with long-term, high-resolution data, appropriate statistics and tests of alternative drivers earn higher Cindex scores, suggesting these should be given greater weight in impact assessments. Together with our proposed framework, the results of our Cindex analysis indicate how the science of detecting and attributing biological impacts to climate change can be strengthened through the use of evidence-based prior expectations and thorough statistical analyses, even when data are limited, maximizing the impact of the diverse and growing climate change ecology literature
HABIT-an early phase study to explore an oral health intervention delivered by health visitors to parents with young children aged 9-12 months: study protocol.
Background: Parental supervised brushing (PSB) when initiated in infancy can lead to long-term protective home-based oral health habits thereby reducing the risk of dental caries. However, PSB is a complex behaviour with many barriers reported by parents hindering its effective implementation. Within the UK, oral health advice is delivered universally to parents by health visitors and their wider teams when children are aged between 9 and 12 months. Nevertheless, there is no standardised intervention or training upon which health visitors can base this advice, and they often lack the specialised knowledge needed to help parents overcome barriers to performing PSB and limiting sugary foods and drinks.Working with health visitors and parents of children aged 9-24 months, we have co-designed oral health training and resources (Health Visitors delivering Advice in Britain on Infant Toothbrushing (HABIT) intervention) to be used by health visitors and their wider teams when providing parents of children aged 9-12 months with oral health advice.The aim of the study is to explore the acceptability of the HABIT intervention to parents and health visitors, to examine the mechanism of action and develop suitable objective measures of PSB. Methods/design: Six health visitors working in a deprived city in the UK will be provided with training on how to use the HABIT intervention. Health visitors will then each deliver the intervention to five parents of children aged 9-12 months. The research team will collect measures of PSB and dietary behaviours before and at 2 weeks and 3 months after the HABIT intervention. Acceptability of the HABIT intervention to health visitors will be explored through semi-structured diaries completed after each visit and a focus group discussion after delivery to all parents. Acceptability of the HABIT intervention and mechanism of action will be explored briefly during each home visit with parents and in greater details in 20-25 qualitative interviews after the completion of data collection. The utility of three objective measures of PSB will be compared with each other and with parental-self reports. Discussion: This study will provide essential information to inform the design of a definitive cluster randomised controlled trial. Trial registration: There is no database for early phase studies such as ours
Quasi-Normal Modes of Stars and Black Holes
Perturbations of stars and black holes have been one of the main topics of
relativistic astrophysics for the last few decades. They are of particular
importance today, because of their relevance to gravitational wave astronomy.
In this review we present the theory of quasi-normal modes of compact objects
from both the mathematical and astrophysical points of view. The discussion
includes perturbations of black holes (Schwarzschild, Reissner-Nordstr\"om,
Kerr and Kerr-Newman) and relativistic stars (non-rotating and
slowly-rotating). The properties of the various families of quasi-normal modes
are described, and numerical techniques for calculating quasi-normal modes
reviewed. The successes, as well as the limits, of perturbation theory are
presented, and its role in the emerging era of numerical relativity and
supercomputers is discussed.Comment: 74 pages, 7 figures, Review article for "Living Reviews in
Relativity
Exoplanet Atmosphere Measurements from Transmission Spectroscopy and other Planet-Star Combined Light Observations
It is possible to learn a great deal about exoplanet atmospheres even when we
cannot spatially resolve the planets from their host stars. In this chapter, we
overview the basic techniques used to characterize transiting exoplanets -
transmission spectroscopy, emission and reflection spectroscopy, and full-orbit
phase curve observations. We discuss practical considerations, including
current and future observing facilities and best practices for measuring
precise spectra. We also highlight major observational results on the
chemistry, climate, and cloud properties of exoplanets.Comment: Accepted review chapter; Handbook of Exoplanets, eds. Hans J. Deeg
and Juan Antonio Belmonte (Springer-Verlag). 22 pages, 6 figure
Using intervention mapping to develop a home-based parental-supervised toothbrushing intervention for young children
BACKGROUND: Dental caries in young children is a major public health problem impacting on the child and their family in terms of pain, infection and substantial financial burden on healthcare funders. In the UK, national guidance on the prevention of dental caries advises parents to supervise their child's brushing with fluoride toothpaste until age 7. However, there is a dearth of evidence-based interventions to encourage this practice in parents. The current study used intervention mapping (IM) to develop a home-based parental-supervised toothbrushing intervention to reduce dental caries in young children. METHODS: The intervention was developed using the six key stages of the IM protocol: (1) needs assessment, including a systematic review, qualitative interviews, and meetings with a multi-disciplinary intervention development group; (2) identification of outcomes and change objectives following identification of the barriers to parental-supervised toothbrushing (PSB), mapped alongside psychological determinants outlined in the Theoretical Domains Framework (TDF); (3) selection of methods and practical strategies; (4) production of a programme plan; (5) adoption and implementation and (6) Evaluation. RESULTS: The comprehensive needs assessment highlighted key barriers to PSB, such as knowledge, skills, self-efficacy, routine setting and behaviour regulation and underlined the importance of individual, social and structural influences. Parenting skills (routine setting and the ability to manage the behaviour of a reluctant child) were emphasised as critical to the success of PSB. The multi-disciplinary intervention development group highlighted the need for both universal and targeted programmes, which could be implemented within current provision. Two intervention pathways were developed: a lower cost universal pathway utilising an existing national programme and an intensive targeted programme delivered via existing parenting programmes. A training manual was created to accompany each intervention to ensure knowledge and standardise implementation procedures. CONCLUSIONS: PSB is a complex behaviour and requires intervention across individual, social and structural levels. IM, although a time-consuming process, allowed us to capture this complexity and allowed us to develop two community-based intervention pathways covering both universal and targeted approaches, which can be integrated into current provision. Further research is needed to evaluate the acceptability and sustainability of these interventions
CD8+ T cells from a novel T cell receptor transgenic mouse induce liver-stage immunity that can be boosted by blood-stage infection in rodent malaria
To follow the fate of CD8+ T cells responsive to Plasmodium berghei ANKA (PbA) infection, we generated an MHC I-restricted TCR transgenic mouse line against this pathogen. T cells from this line, termed PbT-I T cells, were able to respond to blood-stage infection by PbA and two other rodent malaria species, P. yoelii XNL and P. chabaudi AS. These PbT-I T cells were also able to respond to sporozoites and to protect mice from liver-stage infection. Examination of the requirements for priming after intravenous administration of irradiated sporozoites, an effective vaccination approach, showed that the spleen rather than the liver was the main site of priming and that responses depended on CD8α+ dendritic cells. Importantly, sequential exposure to irradiated sporozoites followed two days later by blood-stage infection led to augmented PbT-I T cell expansion. These findings indicate that PbT-I T cells are a highly versatile tool for studying multiple stages and species of rodent malaria and suggest that cross-stage reactive CD8+ T cells may be utilized in liver-stage vaccine design to enable boosting by blood-stage infections
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