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Bennett D.A.,University of Oxford | Little J.,University of Ottawa | Masson L.F.,University of Aberdeen | Minelli C.,European Academy of Bolzano EURAC
BMC Medical Research Methodology | Year: 2011

Background: The Public Population Project in Genomics (P3G) is an organisation that aims to promote collaboration between researchers in the field of population-based genomics. The main objectives of P3G are to encourage collaboration between researchers and biobankers, optimize study design, promote the harmonization of information use in biobanks, and facilitate transfer of knowledge between interested parties. The importance of calibration and harmonisation of methods for environmental exposure assessment to allow pooling of data across studies in the evaluation of gene-environment interactions has been recognised by P3G, which has set up a methodological group on calibration with the aim of; 1) reviewing the published methodological literature on measurement error correction methods with assumptions and methods of implementation; 2) reviewing the evidence available from published nutritional epidemiological studies that have used a calibration approach; 3) disseminating information in the form of a comparison chart on approaches to perform calibration studies and how to obtain correction factors in order to support research groups collaborating within the P3G network that are unfamiliar with the methods employed; 4) with application to the field of nutritional epidemiology, including gene-diet interactions, ultimately developing a inventory of the typical correction factors for various nutrients. Methods/Design. Systematic review of (a) the methodological literature on methods to correct for measurement error in epidemiological studies; and (b) studies that have been designed primarily to investigate the association between diet and disease and have also corrected for measurement error in dietary intake. Discussion. The conduct of a systematic review of the methodological literature on calibration will facilitate the evaluation of methods to correct for measurement error and the design of calibration studies for the prospective pooling of biobanks. This could increase the efficiency of the design of such studies, improve statistical power, reduce bias, and aid in the assessment of gene-environment interaction effects in complex diseases. The systematic review of calibration of dietary intake information could inform gene-diet interaction investigations involving the pooling of results from studies with nutritional data collected in different ways. © 2011 Bennett et al; licensee BioMed Central Ltd. Source

Garcia L.R.,Forest Monitoring and Planning Research Unit CREA MPF | Curetti G.,European Academy of Bolzano EURAC | Garegnani G.,European Academy of Bolzano EURAC | Grilli G.,European Academy of Bolzano EURAC | And 3 more authors.
Bosque | Year: 2016

The values of goods and services by natural resources are not included in the political decision making process concerning natural resources management. This gap is due to the fact that many ecosystem services are not marketed. In order to overcome this gap in the management of natural resources, it is necessary to apply some environmental economic methods to capture the total economic value of marketed and non-marketed ecosystem services. Ecosystem services are not homogeneous across landscapes but they are heterogeneous in space. Consequently, mapping ecosystem services is considered as a fundamental requirement for landscape planning. The aim of this paper is to show a method for the economic valuation and mapping of the forest ecosystem services. The method was applied to a case study characterized by a high importance of ecosystem services and involved in the recharge.green project (Alpine Space Programme): the Gesso-Vermenagna valley in Italy. Results show that the highest economic values are for regulating services (from 11 € ha-1to 4.300 € ha-1per year) and for provisioning services (from 6 € ha-1to 1.980 € ha-1per year), while the lowest values are for cultural services (from 6 € ha-1to 627 € ha-1per year). This study can provide useful information to decision makers in order to improve the management of natural resources at local level. © 2016, Universidad Austral de Chile. All rights reserved. Source

Pattaro C.,European Academy of Bolzano EURAC | Riegler P.,Hemodialysis Unit | Stifter G.,Hospital of Brunico | Modenese M.,European Academy of Bolzano EURAC | And 3 more authors.
Nephron - Clinical Practice | Year: 2013

BackgroundAims: Several formulas for glomerular filtration rate (GFR) estimation, based on serum creatinine or cystatin C, have been proposed. We assessed the impact of some of these equations on estimated GFR (eGFR) and chronic kidney disease (CKD) prevalence, and on the association with cardiovascular risk factors, in a general population sample characterized by a young mean age. Methods: We studied 1,199 individuals from three Alpine villages enrolled into the MICROS study. eGFR was obtained with the 4- and 6-parameter MDRD study equations, the Virga equation, and with the three CKD-EPI formulas for creatinine, cystatin C, and the combination of creatinine and cystatin C. We assessed the concordance between quantitative eGFR levels, CKD prevalence, and in terms of association with total, LDL, and HDL cholesterol. Results: The highest and lowest eGFR levels corresponded to the cystatin C-based and MDRD-4 equations, respectively. CKD prevalence varied from 1.8% (Virga) to 5.8% (MDRD-4). The CKD-EPI based on creatinine showed the highest agreement with all other equations. Agreement between methods was higher at lower eGFR levels, older age, and in the presence of diabetes and hypertension. Creatinine-based estimates of eGFR were associated with total and low-density lipoprotein but not high-density lipoprotein cholesterol. The opposite was observed for the cystatin C-based GFR. Conclusion: GFR estimation is strongly affected by the chosen equation. Differences are more pronounced in healthy and younger individuals. To identify CKD risk factors, the choice of the equation is of secondary importance to the choice of the biomarker used in the formula. If eGFR is not calibrated to a gold standard GFR in the general population, reports about CKD prevalence should be considered with caution. Copyright © 2013 S. Karger AG, Basel. Source

Sun M.,University of Leicester | Jobling M.A.,University of Leicester | Taliun D.,European Academy of Bolzano EURAC | Taliun D.,University of Michigan | And 3 more authors.
Theoretical Population Biology | Year: 2016

There has been recent interest in the exploitation of readily available dense genome scan marker data for the identification of relatives. However, there are conflicting findings on how informative these data are in practical situations and, in particular, sets of thinned markers are often used with no concrete justification for the chosen spacing. We explore the potential usefulness of dense single nucleotide polymorphism (SNP) arrays for this application with a focus on inferring distant relative pairs. We distinguish between relationship estimation, as defined by a pedigree connecting the two individuals of interest, and estimation of general relatedness as would be provided by a kinship coefficient or a coefficient of relatedness. Since our primary interest is in the former case, we adopt a pedigree likelihood approach. We consider the effect of additional SNPs and data on an additional typed relative, together with choice of that relative, on relationship inference. We also consider the effect of linkage disequilibrium. When overall relatedness, rather than the specific relationship, would suffice, we propose an approximate approach that is easy to implement and appears to compete well with a popular moment-based estimator and a recent maximum likelihood approach based on chromosomal sharing. We conclude that denser marker data are more informative for distant relatives. However, linkage disequilibrium cannot be ignored and will be the main limiting factor for applications to real data. © 2015 Elsevier Inc. Source

Saint-Pierre A.,French Institute of Health and Medical Research | Saint-Pierre A.,European Academy of Bolzano EURAC | Saint-Pierre A.,University of Lubeck | D'elia Y.,European Academy of Bolzano EURAC | And 6 more authors.
Human Heredity | Year: 2014

Background: Linkage analysis on extended pedigrees is often challenged by the high computational demand of exact identity-by-descent (IBD) matrix reconstruction. When such an analysis becomes not feasible, two alternative solutions are contrasted: a full pedigree analysis based on approximate IBD estimation versus a pedigree splitting followed by exact IBD estimation. A multiple splitting (MS) approach, which combines linkage results across different splitting configurations, has been proposed to increase the power of single-split solutions. Methods: To assess whether MS can achieve a comparable power to a full pedigree analysis, we compared the power of linkage on a very large pedigree in both simulated and real-case scenarios, using variance components linkage analysis of a dense SNP array. Results: Our results confirm that the power to detect linkage is affected by the pedigree size. The MS approach showed higher power than the single-split analysis, but it was substantially less powerful than the full pedigree approach in both scenarios, at any level of significance and variance explained by a quantitative trait locus. Conclusion: The MS approach should always be preferred to analyses based on a single split but, when adequate computational resources are available, a full pedigree analysis is better than the MS analysis. Rather than focusing on how to best split a pedigree, it might be more valuable to identify computational solutions that can make the IBD estimation of dense-marker maps practically feasible, thus allowing a full pedigree analysis. © 2014 S. Karger AG, Basel. Source

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