Search results for "statistical method"
showing 10 items of 207 documents
Spatial effects of urban public policies on housing values
2009
International audience; Problems of spatial segregation have often stressed on the social status and social capital of a neighbourhood as main driving forces behind housing price formation. In this paper, it is assumed that spatial effects are additional variables worth considering since the impact of urban policies such as social housing policies and urban regeneration policies may permeate outside the areas where they are implemented. Our case study is of the urban area of Dijon (France), where these two types of urban policies have been implemented in the last three decades. Spatial effects are introduced in the hedonic model and a spatial error model is estimated, revealing a positive a…
Cross-Talk Correction Method for Knee Kinematics in Gait Analysis Using Principal Component Analysis (PCA): A New Proposal
2014
International audience; Background: In 3D gait analysis, the knee joint is usually described by the Eulerian way. It consists in breaking down the motion between the articulating bones of the knee into three rotations around three axes: flexion/extension, abduction/adduction and internal/external rotation. However, the definition of these axes is prone to error, such as the "cross-talk'' effect, due to difficult positioning of anatomical landmarks. This paper proposes a correction method, principal component analysis (PCA), based on an objective kinematic criterion for standardization, in order to improve knee joint kinematic analysis. Methods: The method was applied to the 3D gait data of …
Effect of sperm concentration and storage temperature on goat spermatozoa during liquid storage
2020
The use of cooled semen is relatively common in goats. There are a number of advantages of cooled semen doses, including easier handling of artificial insemination (AI) doses, transport, more AI doses per ejaculate, and higher fertility rates in comparison with frozen AI doses. However, cooled semen has a short shelf life. The objective of this study was to examine the effect of temperature and sperm concentration on the in vitro sperm quality during liquid storage for 48 h, including sperm motility and kinetics, response to oxidation, mitochondrial membrane potential (MMP) and DNA fragmentation in goats. Three experiments were performed. In the first, the effects of liquid preservation of …
Spatio-Chromatic Adaptation via Higher-Order Canonical Correlation Analysis of Natural Images
2014
Independent component and canonical correlation analysis are two general-purpose statistical methods with wide applicability. In neuroscience, independent component analysis of chromatic natural images explains the spatio-chromatic structure of primary cortical receptive fields in terms of properties of the visual environment. Canonical correlation analysis explains similarly chromatic adaptation to different illuminations. But, as we show in this paper, neither of the two methods generalizes well to explain both spatio-chromatic processing and adaptation at the same time. We propose a statistical method which combines the desirable properties of independent component and canonical correlat…
Serum γ-glutamyl transferase levels, insulin resistance and liver fibrosis in patients with chronic liver diseases.
2012
Background and Aims: Serum levels of γ-glutamyl-transpeptidase(γ-GT) were associated with liver disease severity and metabolic alterations, which in turn are able to affect hepatic damage. In patients with nonalcoholic fatty liver disease (NAFLD), genotype 1 chronic hepatitis C (G1CHC) and chronic hepatitis B (CHB), we assessed the link between liver fibrosis and γ-GT serum levels, and we evaluated if normal or high γ-GT serum levels affect the association between insulin resistance (IR) and severity of liver fibrosis. Methods: 843 consecutive patients with chronic liver disease (CLD)(193 NAFLD, 481 G1CHC, 169 CHB) were evaluated by liver biopsy (Kleiner and Scheuer scores) and clinical and…
In HCV-related liver cirrhosis, local pulse wave velocity increases and in decompensated patients correlates with poorer survival
2018
BackgroundCirrhotic cardiomyopathy (CCM) refers to cardiac dysfunction in patients with liver cirrhosis, in the absence of other known cardiac disease.MethodsControl group and patients diagnosed of liver cirrhosis without known cardiac disease or hepatocellular carcinoma were enrolled for this clinical observation study. Patients with diabetes mellitus, hypertension were excluded. Absolute global longitudinal strain, one-point carotid pulse wave velocity (one-point PWV) and various parameters were measured in resting status.ResultsThere were 29 participants in the control group and 80 patients in the liver cirrhosis group. 27.8% of cirrhotic patients presented with normal systolic but abnor…
Circulating monocyte subsets and heart failure prognosis
2018
Altres ajuts: Fundacio' La MARATO' de TV3 (201502 to ABG, 201516), AdvanceCat with the support of ACCIÓ [Catalonia Trade & Investment, Generalitat de Catalunya], Fundació Bancària La Caixa. Monocytes are a heterogeneous population of effector cells with key roles in tissue integrity restoration and maintenance. Here, we explore the association of monocyte subsets and prognosis in patients with ambulatory heart failure (HF). Monocyte subsets were classified as classical (CD14 ++ /CD16 -), intermediate (CD14 ++ /CD16 +), or non-classical (CD14 + /CD16 ++). Percentage distribution and absolute cell count were assessed in each subset, and multivariable Cox regression analyses were performed wit…
Removing Batch Effects from Longitudinal Gene Expression - Quantile Normalization Plus ComBat as Best Approach for Microarray Transcriptome Data
2016
International audience; Technical variation plays an important role in microarray-based gene expression studies, and batch effects explain a large proportion of this noise. It is therefore mandatory to eliminate technical variation while maintaining biological variability. Several strategies have been proposed for the removal of batch effects, although they have not been evaluated in large-scale longitudinal gene expression data. In this study, we aimed at identifying a suitable method for batch effect removal in a large study of microarray-based longitudinal gene expression. Monocytic gene expression was measured in 1092 participants of the Gutenberg Health Study at baseline and 5-year fol…
Association of Common Polymorphisms in the Nicotinic Acetylcholine Receptor Alpha4 Subunit Gene with an Electrophysiological Endophenotype in a Large…
2016
PLoS one 11(4), e0152984 (2016). doi:10.1371/journal.pone.0152984
Genome-Wide Association Study for Incident Myocardial Infarction and Coronary Heart Disease in Prospective Cohort Studies: The CHARGE Consortium
2016
Background Data are limited on genome-wide association studies (GWAS) for incident coronary heart disease (CHD). Moreover, it is not known whether genetic variants identified to date also associate with risk of CHD in a prospective setting. Methods We performed a two-stage GWAS analysis of incident myocardial infarction (MI) and CHD in a total of 64,297 individuals (including 3898 MI cases, 5465 CHD cases). SNPs that passed an arbitrary threshold of 5×10−6 in Stage I were taken to Stage II for further discovery. Furthermore, in an analysis of prognosis, we studied whether known SNPs from former GWAS were associated with total mortality in individuals who experienced MI during follow-up. Res…