68 research outputs found
What can computed tomography and magnetic resonance imaging tell us about ventilation?
This review provides a summary of pulmonary functional imaging approaches for determining pulmonary ventilation, with a specific focus on multi-detector x-ray computed tomography and magnetic resonance imaging (MRI). We provide the important functional definitions of pulmonary ventilation typically used in medicine and physiology and discuss the fact that some of the imaging literature describes gas distribution abnormalities in pulmonary disease that may or may not be related to the physiological definition or clinical interpretation of ventilation. We also review the current state-of-the-field in terms of the key physiological questions yet unanswered related to ventilation and gas distribution in lung disease. Current and emerging imaging research methods are described, including their strengths and the challenges that remain to translate these methods to more wide-spread research and clinical use. We also examine how computed tomography and MRI might be used in the future to gain more insight into gas distribution and ventilation abnormalities in pulmonary disease
A Review of Hot Deck Imputation for Survey Non-response
L'imputation hot deck est une méthode de gestion des données manquantes dans laquelle chaque valeur manquante est remplacée par une réponse observée à partir d'une unité“similaire.” Bien qu'elle soit largement utilisée en pratique, sa théorie n'est pas aussi développée que celle des autres méthodes d'imputation. Nous avons constaté qu'il n'existe aucun consensus quant à la meilleure faon d'appliquer les hot deck et obtenir des inférences à partir de la série de données complète. Ici, nous passons en revue les différentes formes de hot deck et les recherches existantes sur ses propriétés statistiques. Nous décrivons les applications du hot deck actuellement utilisées, y compris le hot deck du Bureau US du recensement pour la Current Population Survey (CPS). Nous proposons aussi des exemples nombreux de variations du hot deck à la troisième National Health and Nutrition Examination Survey (NHANES III). Certains domaines possibles de recherches futures sont mises en évidence.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78729/1/j.1751-5823.2010.00103.x.pd
Population Empirical Likelihood Estimation in Dual Frame Surveys
Dual frame surveys are a device to reduce the costs derived from data
collection in surveys and improve coverage for the whole target population. Since
their introduction, in the 1960’s, dual frame surveys have gained much attention
and several estimators have been formulated based on a number of different approaches. In this work, we propose new dual frame estimators based on the population empirical likelihood method originally proposed by Chen and Kim (2014) and
using both the dual and the single frame approach. The extension of the proposed
methodology to more than two frame surveys is also sketched. The performance
of the proposed estimators in terms of relative bias and relative mean squared
error is tested through simulation experiments. These experiments indicate that
the proposed estimators yield better results than other likelihood-based estimators
proposed in the literature.Ministerio de Economía y Competitividad of Spai
Variation in the SERPINA6SERPINA1 locusalters morning plasma cortisol, hepatic corticosteroid binding globulin expression, gene expressionin peripheral tissues, and risk of cardiovascular disease
The stress hormone cortisol modulates fuel metabolism, cardiovascular homoeostasis, mood, inflammation and cognition. The CORtisol NETwork (CORNET) consortium previously identified a single locus associated with morning plasma cortisol. Identifying additional genetic variants that explain more of the variance in cortisol could provide new insights into cortisol biology and provide statistical power to test the causative role of cortisol in common diseases. The CORNET consortium extended its genome-wide association meta-analysis for morning plasma cortisol from 12,597 to 25,314 subjects and from ~2.2 M to ~7 M SNPs, in 17 population-based cohorts of European ancestries. We confirmed the genetic association with SERPINA6/SERPINA1. This locus contains genes encoding corticosteroid binding globulin (CBG) and α1-antitrypsin. Expression quantitative trait loci (eQTL) analyses undertaken in the STARNET cohort of 600 individuals showed that specific genetic variants within the SERPINA6/SERPINA1 locus influence expression of SERPINA6 rather than SERPINA1 in the liver. Moreover, trans-eQTL analysis demonstrated effects on adipose tissue gene expression, suggesting that variation
Identification of Intracellular and Plasma Membrane Calcium Channel Homologues in Pathogenic Parasites
Ca2+ channels regulate many crucial processes within cells and their abnormal activity can be damaging to cell survival, suggesting that they might represent attractive therapeutic targets in pathogenic organisms. Parasitic diseases such as malaria, leishmaniasis, trypanosomiasis and schistosomiasis are responsible for millions of deaths each year worldwide. The genomes of many pathogenic parasites have recently been sequenced, opening the way for rational design of targeted therapies. We analyzed genomes of pathogenic protozoan parasites as well as the genome of Schistosoma mansoni, and show the existence within them of genes encoding homologues of mammalian intracellular Ca2+ release channels: inositol 1,4,5-trisphosphate receptors (IP3Rs), ryanodine receptors (RyRs), two-pore Ca2+ channels (TPCs) and intracellular transient receptor potential (Trp) channels. The genomes of Trypanosoma, Leishmania and S. mansoni parasites encode IP3R/RyR and Trp channel homologues, and that of S. mansoni additionally encodes a TPC homologue. In contrast, apicomplexan parasites lack genes encoding IP3R/RyR homologues and possess only genes encoding TPC and Trp channel homologues (Toxoplasma gondii) or Trp channel homologues alone. The genomes of parasites also encode homologues of mammalian Ca2+ influx channels, including voltage-gated Ca2+ channels and plasma membrane Trp channels. The genome of S. mansoni also encodes Orai Ca2+ channel and STIM Ca2+ sensor homologues, suggesting that store-operated Ca2+ entry may occur in this parasite. Many anti-parasitic agents alter parasite Ca2+ homeostasis and some are known modulators of mammalian Ca2+ channels, suggesting that parasite Ca2+ channel homologues might be the targets of some current anti-parasitic drugs. Differences between human and parasite Ca2+ channels suggest that pathogen-specific targeting of these channels may be an attractive therapeutic prospect
Normalizing computed tomography data reconstructed with different filter kernels: effect on emphysema quantification
Variation in the SERPINA6/SERPINA1 locus alters morning plasma cortisol, hepatic corticosteroid binding globulin expression, gene expression in peripheral tissues, and risk of cardiovascular disease
The stress hormone cortisol modulates fuel metabolism, cardiovascular homoeostasis, mood, inflammation and cognition. The CORtisol NETwork (CORNET) consortium previously identified a single locus associated with morning plasma cortisol. Identifying additional genetic variants that explain more of the variance in cortisol could provide new insights into cortisol biology and provide statistical power to test the causative role of cortisol in common diseases. The CORNET consortium extended its genome-wide association meta-analysis for morning plasma cortisol from 12,597 to 25,314 subjects and from similar to 2.2 M to similar to 7 M SNPs, in 17 population-based cohorts of European ancestries. We confirmed the genetic association with SERPINA6/SERPINA1. This locus contains genes encoding corticosteroid binding globulin (CBG) and alpha 1-antitrypsin. Expression quantitative trait loci (eQTL) analyses undertaken in the STARNET cohort of 600 individuals showed that specific genetic variants within the SERPINA6/SERPINA1 locus influence expression of SERPINA6 rather than SERPINA1 in the liver. Moreover, trans-eQTL analysis demonstrated effects on adipose tissue gene expression, suggesting that variations in CBG levels have an effect on delivery of cortisol to peripheral tissues. Two-sample Mendelian randomisation analyses provided evidence that each genetically-determined standard deviation (SD) increase in morning plasma cortisol was associated with increased odds of chronic ischaemic heart disease (0.32, 95% CI 0.06-0.59) and myocardial infarction (0.21, 95% CI 0.00-0.43) in UK Biobank and similarly in CARDIoGRAMplusC4D. These findings reveal a causative pathway for CBG in determining cortisol action in peripheral tissues and thereby contributing to the aetiology of cardiovascular disease.</p
Portrayals of the Holocaust in English history textbooks, 1991–2016: continuities, challenges and concerns
This study examines portrayals of the Holocaust in a sample of 21 secondary school history textbooks published in England between 1991 and 2016. Evaluated against internationally recognized criteria and guidelines, the content of most textbooks proved very problematic. Typically, textbooks failed to provide clear chronological and geographical frameworks and adopted simplistic Hitler-centric, perpetrator-oriented narratives. Furthermore, textbooks paid limited attention to pre-war Jewish life, the roots of antisemitism, the complicity of local populations and collaborationist regimes, and the impact of the Holocaust on people across Europe. Based on these critical findings, the article concludes by offering initial recommendations for textbook improvement
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