| 31. |
- Atkin, Owen K, et al.
(author)
-
Using temperature-dependent changes in leaf scaling relationships to quantitatively account forthermal acclimation of respiration in a coupled global climate-vegetation model
- 2008
-
In: Global Change Biology. - : Wiley. - 1354-1013. ; 14, s. 2709-2726
-
Journal article (peer-reviewed)abstract
- The response of plant respiration (R) to temperature is an important component of the biosphere's response to climate change. At present, most global models assume that R increases exponentially with temperature and does not thermally acclimate. Although we now know that acclimation does occur, quantitative incorporation of acclimation into models has been lacking. Using a dataset for 19 species grown at four temperatures (7, 14, 21, and 28 °C), we have assessed whether sustained differences in growth temperature systematically alter the slope and/or intercepts of the generalized log–log plots of leaf R vs. leaf mass per unit leaf area (LMA) and vs. leaf nitrogen (N) concentration. The extent to which variations in growth temperature account for the scatter observed in log–log R–LMA–N scaling relationships was also assessed. We show that thermal history accounts for up to 20% of the scatter in scaling relationships used to predict R, with the impact of thermal history on R–LMA–N generalized scaling relationships being highly predictable. This finding enabled us to quantitatively incorporate acclimation of R into a coupled global climate–vegetation model. We show that accounting for acclimation of R has negligible impact on predicted annual rates of global R, net primary productivity (NPP) or future atmospheric CO2 concentrations. However, our analysis suggests that accounting for acclimation is important when considering carbon fluxes among thermally contrasting biomes (e.g. accounting for acclimation decreases predicted rates of R by up to 20% in high-temperature biomes). We conclude that acclimation of R needs to be accounted for when predicting potential responses of terrestrial carbon exchange to climatic change at a regional level.
|
|
| 32. |
- Beard, David J., et al.
(author)
-
Considerations and methods for placebo controls in surgical trials (ASPIRE guidelines)
- 2020
-
In: The Lancet. - 0140-6736. ; 395:10226, s. 828-838
-
Research review (peer-reviewed)abstract
- Placebo comparisons are increasingly being considered for randomised trials assessing the efficacy of surgical interventions. The aim of this Review is to provide a summary of knowledge on placebo controls in surgical trials. A placebo control is a complex type of comparison group in the surgical setting and, although powerful, presents many challenges. This Review outlines what a placebo control entails and present understanding of this tool in the context of surgery. We consider when placebo controls in surgery are acceptable (and when they are desirable) in terms of ethical arguments and regulatory requirements, how a placebo control should be designed, how to identify and mitigate risk for participants in these trials, and how such trials should be done and interpreted. Use of placebo controls is justified in randomised controlled trials of surgical interventions provided there is a strong scientific and ethical rationale. Surgical placebos might be most appropriate when there is poor evidence for the efficacy of the procedure and a justified concern that results of a trial would be associated with high risk of bias, particularly because of the placebo effect. Feasibility work is recommended to optimise the design and implementation of randomised controlled trials. This Review forms an outline for best practice and provides guidance, in the form of the Applying Surgical Placebo in Randomised Evaluations (known as ASPIRE) checklist, for those considering the use of a placebo control in a surgical randomised controlled trial.
|
|
| 33. |
- Beard, David J., et al.
(author)
-
Placebo comparator group selection and use in surgical trials : The aspire project including expert workshop
- 2021
-
In: Health Technology Assessment. - 1366-5278. ; 25:53
-
Journal article (peer-reviewed)abstract
- Background: The use of placebo comparisons for randomised trials assessing the efficacy of surgical interventions is increasingly being considered. However, a placebo control is a complex type of comparison group in the surgical setting and, although powerful, presents many challenges. Objectives: To provide a summary of knowledge on placebo controls in surgical trials and to summarise any recommendations for designers, evaluators and funders of placebo-controlled surgical trials. Design: To carry out a state-of-the-art workshop and produce a corresponding report involving key stakeholders throughout. Setting: A workshop to discuss and summarise the existing knowledge and to develop the new guidelines. Results: To assess what a placebo control entails and to assess the understanding of this tool in the context of surgery is considered, along with when placebo controls in surgery are acceptable (and when they are desirable). We have considered ethics arguments and regulatory requirements, how a placebo control should be designed, how to identify and mitigate risk for participants in these trials, and how such trials should be carried out and interpreted. The use of placebo controls is justified in randomised controlled trials of surgical interventions provided that there is a strong scientific and ethics rationale. Surgical placebos might be most appropriate when there is poor evidence for the efficacy of the procedure and a justified concern that results of a trial would be associated with a high risk of bias, particularly because of the placebo effect. Conclusions: The use of placebo controls is justified in randomised controlled trials of surgical interventions provided that there is a strong scientific and ethics rationale. Feasibility work is recommended to optimise the design and implementation of randomised controlled trials. An outline for best practice was produced in the form of the Applying Surgical Placebo in Randomised Evaluations (ASPIRE) guidelines for those considering the use of a placebo control in a surgical randomised controlled trial. Limitations: Although the workshop participants involved international members, the majority of participants were from the UK. Therefore, although every attempt was made to make the recommendations applicable to all health systems, the guidelines may, unconsciously, be particularly applicable to clinical practice in the UK NHS. Future work: Future work should evaluate the use of the ASPIRE guidelines in making decisions about the use of a placebo-controlled surgical trial. In addition, further work is required on the appropriate nomenclature to adopt in this space.
|
|
| 34. |
- Boeger, Carsten A., et al.
(author)
-
CUBN Is a Gene Locus for Albuminuria
- 2011
-
In: Journal of the American Society of Nephrology. - 1046-6673 .- 1533-3450. ; 22:3, s. 555-570
-
Journal article (peer-reviewed)abstract
- Identification of genetic risk factors for albuminuria may alter strategies for early prevention of CKD progression, particularly among patients with diabetes. Little is known about the influence of common genetic variants on albuminuria in both general and diabetic populations. We performed a meta-analysis of data from 63,153 individuals of European ancestry with genotype information from genome-wide association studies (CKDGen Consortium) and from a large candidate gene study (CARe Consortium) to identify susceptibility loci for the quantitative trait urinary albumin-to-creatinine ratio (UACR) and the clinical diagnosis microalbuminuria. We identified an association between a missense variant (I2984V) in the CUBN gene, which encodes cubilin, and both UACR (P = 1.1 x 10(-11)) and microalbuminuria (P = 0.001). We observed similar associations among 6981 African Americans in the CARe Consortium. The associations between this variant and both UACR and microalbuminuria were significant in individuals of European ancestry regardless of diabetes status. Finally, this variant associated with a 41% increased risk for the development of persistent microalbuminuria during 20 years of follow-up among 1304 participants with type 1 diabetes in the prospective DCCT/EDIC Study. In summary, we identified a missense CUBN variant that associates with levels of albuminuria in both the general population and in individuals with diabetes.
|
|
| 35. |
- Calvert, Clara, et al.
(author)
-
Changes in preterm birth and stillbirth during COVID-19 lockdowns in 26 countries
- 2023
-
In: Nature Human Behaviour. - : Springer Nature. - 2397-3374. ; 7:4, s. 529-544
-
Journal article (peer-reviewed)abstract
- Preterm birth (PTB) is the leading cause of infant mortality worldwide. Changes in PTB rates, ranging from -90% to +30%, were reported in many countries following early COVID-19 pandemic response measures ('lockdowns'). It is unclear whether this variation reflects real differences in lockdown impacts, or perhaps differences in stillbirth rates and/or study designs. Here we present interrupted time series and meta-analyses using harmonized data from 52 million births in 26 countries, 18 of which had representative population-based data, with overall PTB rates ranging from 6% to 12% and stillbirth ranging from 2.5 to 10.5 per 1,000 births. We show small reductions in PTB in the first (odds ratio 0.96, 95% confidence interval 0.95-0.98, P value <0.0001), second (0.96, 0.92-0.99, 0.03) and third (0.97, 0.94-1.00, 0.09) months of lockdown, but not in the fourth month of lockdown (0.99, 0.96-1.01, 0.34), although there were some between-country differences after the first month. For high-income countries in this study, we did not observe an association between lockdown and stillbirths in the second (1.00, 0.88-1.14, 0.98), third (0.99, 0.88-1.12, 0.89) and fourth (1.01, 0.87-1.18, 0.86) months of lockdown, although we have imprecise estimates due to stillbirths being a relatively rare event. We did, however, find evidence of increased risk of stillbirth in the first month of lockdown in high-income countries (1.14, 1.02-1.29, 0.02) and, in Brazil, we found evidence for an association between lockdown and stillbirth in the second (1.09, 1.03-1.15, 0.002), third (1.10, 1.03-1.17, 0.003) and fourth (1.12, 1.05-1.19, <0.001) months of lockdown. With an estimated 14.8 million PTB annually worldwide, the modest reductions observed during early pandemic lockdowns translate into large numbers of PTB averted globally and warrant further research into causal pathways.
|
|
| 36. |
|
|
| 37. |
- Campbell, Ian A., et al.
(author)
-
Hyperscaling Violation in Ising Spin Glasses
- 2019
-
In: Entropy. - : MDPI. - 1099-4300. ; 21:10
-
Journal article (peer-reviewed)abstract
- In addition to the standard scaling rules relating critical exponents at second order transitions, hyperscaling rules involve the dimension of the model. It is well known that in canonical Ising models hyperscaling rules are modified above the upper critical dimension. It was shown by M. Schwartz in 1991 that hyperscaling can also break down in Ising systems with quenched random interactions; Random Field Ising models, which are in this class, have been intensively studied. Here, numerical Ising Spin Glass data relating the scaling of the normalized Binder cumulant to that of the reduced correlation length are presented for dimensions 3, 4, 5, and 7. Hyperscaling is clearly violated in dimensions 3 and 4, as well as above the upper critical dimension D=6. Estimates are obtained for the "violation of hyperscaling exponent" values in the various models.
|
|
| 38. |
- Campbell, Ian, et al.
(author)
-
The evolution of surface flow stripes and stratigraphic folds within Kamb Ice Stream : why don't they match?
- 2008
-
In: Journal of Glaciology. - : International Glaciological Society. - 0022-1430 .- 1727-5652. ; 54:186, s. 421-427
-
Journal article (peer-reviewed)abstract
- Flow stripes seen in satellite imagery of ice streams and ice shelves are caused by surface undulations with kilometer-scale spacing and meter-scale relief and generally indicate current or recent fast ice flow. On a similar scale, folding of internal ice stratigraphy depicted in cross-flow icepenetrating radar profiles is also a common occurrence in ice streams, suggesting a possible relationship between the two sets of features. We have traced surface flow stripes in RADARSAT and MODIS imagery on Kamb Ice Stream, West Antarctica, from the onset of streaming flow into the near-stagnant trunk. We compare the morphology and evolution of the surface flow stripes to the folds seen in the internal stratigraphy in cross-ice-stream radar profiles. We find essentially no correspondence in the observed locations or spacings between the radar internal layer folds at depths greater than 100 m and the flow stripes on the surface. The gap in the radar data and the surface mappings in the top 100m of firn prevents a precise depiction of how the flow stripes and fold patterns at depth diverge. We explore hypotheses about how flow stripes and internal stratigraphic folds can originate and evolve differently as ice flows downstream. We suggest that flow stripes are subject to surface processes that can modify their morphology independently of the internal stratigraphy, leading to changes in the pattern of flow stripes relative to the internal layers below.
|
|
| 39. |
- Campbell, Ian, et al.
(author)
-
The relation between the age at diagnosis of problem behaviors related to aggression and distal outcomes in Swedish children
- 2019
-
In: European Child and Adolescent Psychiatry. - : Springer. - 1018-8827 .- 1435-165X. ; 28:7, s. 899-911
-
Journal article (peer-reviewed)abstract
- Severe childhood aggressive behaviors are known to predict negative outcomes later in life; however, little is known about the effect of when in childhood aggression problems are diagnosed. While an earlier first diagnosis of problematic aggressive behavior might be associated with increased severity and, thus, worse outcomes, it is also possible that an earlier diagnosis affords an earlier start of treatment programs or indicates that greater attention is being paid to behavioral problems, thus resulting in attenuation of the severity of childhood aggression's impact on distal outcomes. The current study analyzed data from the population-based Swedish Data Registries, which include data on all children formally diagnosed by the Swedish medical system with a wide range of aggression problems between ages 8 and 18 (N = 5816) during the years 1987-2013, along with a matched control. Time-to-event analyses investigated whether the age at time of diagnosis affects later life outcomes while controlling for relevant confounders. Results show that for both boys and girls, those with a later diagnosis had lower average incomes (regression coefficient b = - 0.055, p < 0.005) and a higher probability of having a criminal record (odds ratio 1.126, p < 0.005) than children with earlier diagnoses. The effect on suicide attempts was not significant after correcting for multiple testing (odds ratio 1.264, p = 0.016). Grade score was not significantly affected. The results warrant further research concerning the potential advantage of earlier diagnoses, especially concerning generalizability beyond the Swedish population.
|
|
| 40. |
- Chasman, Daniel I., et al.
(author)
-
Integration of genome-wide association studies with biological knowledge identifies six novel genes related to kidney function
- 2012
-
In: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 21:24, s. 5329-5343
-
Journal article (peer-reviewed)abstract
- In conducting genome-wide association studies (GWAS), analytical approaches leveraging biological information may further understanding of the pathophysiology of clinical traits. To discover novel associations with estimated glomerular filtration rate (eGFR), a measure of kidney function, we developed a strategy for integrating prior biological knowledge into the existing GWAS data for eGFR from the CKDGen Consortium. Our strategy focuses on single nucleotide polymorphism (SNPs) in genes that are connected by functional evidence, determined by literature mining and gene ontology (GO) hierarchies, to genes near previously validated eGFR associations. It then requires association thresholds consistent with multiple testing, and finally evaluates novel candidates by independent replication. Among the samples of European ancestry, we identified a genome-wide significant SNP in FBXL20 (P 5.6 10(9)) in meta-analysis of all available data, and additional SNPs at the INHBC, LRP2, PLEKHA1, SLC3A2 and SLC7A6 genes meeting multiple-testing corrected significance for replication and overall P-values of 4.5 10(4)2.2 10(7). Neither the novel PLEKHA1 nor FBXL20 associations, both further supported by association with eGFR among African Americans and with transcript abundance, would have been implicated by eGFR candidate gene approaches. LRP2, encoding the megalin receptor, was identified through connection with the previously known eGFR gene DAB2 and extends understanding of the megalin system in kidney function. These findings highlight integration of existing genome-wide association data with independent biological knowledge to uncover novel candidate eGFR associations, including candidates lacking known connections to kidney-specific pathways. The strategy may also be applicable to other clinical phenotypes, although more testing will be needed to assess its potential for discovery in general.
|
|
