scispace - formally typeset
Search or ask a question
Institution

University of Aberdeen

EducationAberdeen, United Kingdom
About: University of Aberdeen is a education organization based out in Aberdeen, United Kingdom. It is known for research contribution in the topics: Population & Randomized controlled trial. The organization has 21174 authors who have published 49962 publications receiving 2105479 citations. The organization is also known as: Aberdeen University.


Papers
More filters
Journal ArticleDOI
TL;DR: This study aimed to investigate whether the properties of cannabidiol extend to CB1 receptors expressed in mouse brain and to human CB2 receptors that have been transfected into CHO cells.
Abstract: Background and purpose: A nonpsychoactive constituent of the cannabis plant, cannabidiol has been demonstrated to have low affinity for both cannabinoid CB1 and CB2 receptors. We have shown previously that cannabidiol can enhance electrically evoked contractions of the mouse vas deferens, suggestive of inverse agonism. We have also shown that cannabidiol can antagonize cannabinoid receptor agonists in this tissue with a greater potency than we would expect from its poor affinity for cannabinoid receptors. This study aimed to investigate whether these properties of cannabidiol extend to CB1 receptors expressed in mouse brain and to human CB2 receptors that have been transfected into CHO cells.

639 citations

Journal ArticleDOI
09 Oct 2014-Nature
TL;DR: A global, spatially explicit and observation-based assessment of whole-ecosystem carbon turnover times that combines new estimates of vegetation and soil organic carbon stocks and fluxes finds that the overall mean global carbon turnover time is years (95 per cent confidence interval).
Abstract: The response of the terrestrial carbon cycle to climate change is among the largest uncertainties affecting future climate change projections. The feedback between the terrestrial carbon cycle and climate is partly determined by changes in the turnover time of carbon in land ecosystems, which in turn is an ecosystem property that emerges from the interplay between climate, soil and vegetation type. Here we present a global, spatially explicit and observation-based assessment of whole-ecosystem carbon turnover times that combines new estimates of vegetation and soil organic carbon stocks and fluxes. We find that the overall mean global carbon turnover time is 23(+7)(-4) years (95 per cent confidence interval). On average, carbon resides in the vegetation and soil near the Equator for a shorter time than at latitudes north of 75° north (mean turnover times of 15 and 255 years, respectively). We identify a clear dependence of the turnover time on temperature, as expected from our present understanding of temperature controls on ecosystem dynamics. Surprisingly, our analysis also reveals a similarly strong association between turnover time and precipitation. Moreover, we find that the ecosystem carbon turnover times simulated by state-of-the-art coupled climate/carbon-cycle models vary widely and that numerical simulations, on average, tend to underestimate the global carbon turnover time by 36 per cent. The models show stronger spatial relationships with temperature than do observation-based estimates, but generally do not reproduce the strong relationships with precipitation and predict faster carbon turnover in many semi-arid regions. Our findings suggest that future climate/carbon-cycle feedbacks may depend more strongly on changes in the hydrological cycle than is expected at present and is considered in Earth system models.

638 citations

Journal ArticleDOI
TL;DR: Life-history trade-offs between components of fitness arise because reproduction entails both gains and costs, and knowledge of these physiological costs is currently at best described as rudimentary.
Abstract: Life-history trade-offs between components of fitness arise because reproduction entails both gains and costs. Costs of reproduction can be divided into ecological and physiological costs. The latter have been rarely studied yet are probably a dominant component of the effect. A deeper understanding of life-history evolution will only come about once these physiological costs are better understood. Physiological costs may be direct or indirect. Direct costs include the energy and nutrient demands of the reproductive event, and the morphological changes that are necessary to facilitate achieving these demands. Indirect costs may be optional ‘compensatory costs’ whereby the animal chooses to reduce investment in some other aspect of its physiology to maximize the input of resource to reproduction. Such costs may be distinguished from consequential costs that are an inescapable consequence of the reproductive event. In small mammals, the direct costs of reproduction involve increased energy, protein and calcium demands during pregnancy, but most particularly during lactation. Organ remodelling is necessary to achieve the high demands of lactation and involves growth of the alimentary tract and associated organs such as the liver and pancreas. Compensatory indirect costs include reductions in thermogenesis, immune function and physical activity. Obligatory consequential costs include hyperthermia, bone loss, disruption of sleep patterns and oxidative stress. This is unlikely to be a complete list. Our knowledge of these physiological costs is currently at best described as rudimentary. For some, we do not even know whether they are compensatory or obligatory. For almost all of them, we have no idea of exact mechanisms or how these costs translate into fitness trade-offs.

638 citations

Journal ArticleDOI
TL;DR: The aim was to identify techniques that could be reasonably used to elicit public views on the provision of healthcare and to make recommendations regarding the use of methods and future research.
Abstract: Background Limited resources coupled with unlimited demand for healthcare mean that decisions have to be made regarding the allocation of scarce resources across competing interventions. Policy documents have advocated the importance of public views as one such criterion. In principle, the elicitation of public values represents a big step forward. However, for the exercise to be worthwhile, useful information must be obtained that is scientifically defensible, whilst decision-makers must be able and willing to use it. Aims and objectives The aim was to identify techniques that could be reasonably used to elicit public views on the provision of healthcare. Hence, the objectives were: (1) to identify research methods with the potential to take account of public views on the delivery of healthcare; (2) to identify criteria for assessing these methods; (3) to assess the methods identified according to the predefined criteria; (4) to assess the importance of public views vis-a-vis other criteria for setting priorities, as judged by a sample of decision-makers; (5) to make recommendations regarding the use of methods and future research. Methods A systematic literature review was carried out to identify methods for eliciting public views. Criteria currently used to evaluate such methods were identified. The methods identified were then evaluated according to predefined criteria. A questionnaire-based survey assessed the relative importance of public views vis-a-vis five other criteria for setting priorities: potential health gain; evidence of clinical effectiveness; budgetary impact; equity of access and health status inequalities; and quality of service. Two techniques were used: choice-based conjoint analysis and allocation of points technique. The questionnaire was sent to 143 participants. A subsample was followed up with a telephone interview. Results The methods identified were classified as quantitative or qualitative. RESULTS - QUANTITATIVE TECHNIQUES: Quantitative techniques, classified as ranking, rating or choice-based approaches, were evaluated according to eight criteria: validity; reproducibility; internal consistency; acceptability to respondents; cost (financial and administrative); theoretical basis; whether the technique offered a constrained choice; and whether the technique provided a strength of preference measure. Regarding ranking exercises, simple ranking exercises have proved popular, but their results are of limited use. The qualitative discriminant process has not been used to date in healthcare, but may be useful. Conjoint analysis ranking exercises did well against the above criteria. A number of rating scales were identified. The visual analogue scale has proved popular within the quality-adjusted life-year paradigm, but lacks constrained choice and may not measure strength of preference. However, conjoint analysis rating scales performed well. Methods identified for eliciting attitudes include Likert scales, the semantic differential technique, and the Guttman scale. These methods provide useful information, but do not consider strength of preference or the importance of different components within a total score. Satisfaction surveys have been frequently used to elicit public opinion. Researchers should ensure that they construct sensitive techniques, despite their limited use, or else use generic techniques where validity has already been established. Service quality (SERVQUAL) appears to be a potentially useful technique and its application should be researched. Three choice-based techniques with a limited application in healthcare are measure of value, the analytical hierarchical process and the allocation of points technique, while those more widely used, and which did well against the predefined criteria, include standard gamble, time trade-off, discrete choice conjoint analysis and willingness to pay. Little methodological work is currently available on the person trade-off. RESULTS - QUALITATIVE TECHNIQUES: Qualitative techniques were classified as either individual or group-based approaches. Individual approaches included one-to-one interviews, dyadic interviews, case study analyses, the Delphi technique and complaints procedures. Group-based methods included focus groups, concept mapping, citizens' juries, consensus panels, public meetings and nominal group techniques. Six assessment criteria were identified: validity; reliability; generalisability; objectivity; acceptability to respondents; and cost. Whilst all the methods have distinct strengths and weaknesses, there is a lot of ambiguity in the literature. Whether to use individual or group methods depends on the specific topic being discussed and the people being asked, but for both it is crucial that the interviewer/moderator remains as objective as possible. The most popular and widely used such methods were one-to-one interviews and focus groups. (ABSTRACT TRUNCATED)

638 citations

Journal ArticleDOI
TL;DR: Efforts are required to avoid poor calibration when developing prediction models, to evaluate calibration when validating models, and to update models when indicated to optimize the utility of predictive analytics for shared decision-making and patient counseling.
Abstract: The assessment of calibration performance of risk prediction models based on regression or more flexible machine learning algorithms receives little attention. Herein, we argue that this needs to change immediately because poorly calibrated algorithms can be misleading and potentially harmful for clinical decision-making. We summarize how to avoid poor calibration at algorithm development and how to assess calibration at algorithm validation, emphasizing balance between model complexity and the available sample size. At external validation, calibration curves require sufficiently large samples. Algorithm updating should be considered for appropriate support of clinical practice. Efforts are required to avoid poor calibration when developing prediction models, to evaluate calibration when validating models, and to update models when indicated. The ultimate aim is to optimize the utility of predictive analytics for shared decision-making and patient counseling.

635 citations


Authors

Showing all 21424 results

NameH-indexPapersCitations
Paul M. Thompson1832271146736
Feng Zhang1721278181865
Ian J. Deary1661795114161
Peter A. R. Ade1621387138051
David W. Johnson1602714140778
Pete Smith1562464138819
Naveed Sattar1551326116368
John R. Hodges14981282709
Ruth J. F. Loos14264792485
Alan J. Silman14170892864
Michael J. Keating140116976353
David Price138168793535
John D. Scott13562583878
Aarno Palotie12971189975
Rajat Gupta126124072881
Network Information
Related Institutions (5)
University of Edinburgh
151.6K papers, 6.6M citations

95% related

University College London
210.6K papers, 9.8M citations

94% related

University of Manchester
168K papers, 6.4M citations

94% related

University of Oxford
258.1K papers, 12.9M citations

94% related

University of Cambridge
282.2K papers, 14.4M citations

94% related

Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
2023141
2022362
20212,195
20202,118
20191,846
20181,894