138 research outputs found
L’industrie du sucre et du sirop d’érable au canada
Kuentz L. L’industrie du sucre et du sirop d’érable au Canada. In: La Terre et La Vie, Revue d'Histoire naturelle, tome 3, n°6, 1933. pp. 355-361
ClustOfVar: An R Package for the Clustering of Variables
Clustering of variables is as a way to arrange variables into homogeneous
clusters, i.e., groups of variables which are strongly related to each other
and thus bring the same information. These approaches can then be useful for
dimension reduction and variable selection. Several specific methods have been
developed for the clustering of numerical variables. However concerning
qualitative variables or mixtures of quantitative and qualitative variables,
far fewer methods have been proposed. The R package ClustOfVar was specifically
developed for this purpose. The homogeneity criterion of a cluster is defined
as the sum of correlation ratios (for qualitative variables) and squared
correlations (for quantitative variables) to a synthetic quantitative variable,
summarizing "as good as possible" the variables in the cluster. This synthetic
variable is the first principal component obtained with the PCAMIX method. Two
algorithms for the clustering of variables are proposed: iterative relocation
algorithm and ascendant hierarchical clustering. We also propose a bootstrap
approach in order to determine suitable numbers of clusters. We illustrate the
methodologies and the associated package on small datasets
New insights into potocki-shaffer syndrome: Report of two novel cases and literature review
Potocki-Shaffer syndrome (PSS) is a rare non-recurrent contiguous gene deletion syndrome involving chromosome 11p11.2. Current literature implies a minimal region with haploinsufficiency of three genes, ALX4 (parietal foramina), EXT2 (multiple exostoses), and PHF21A (craniofacial anomalies, and intellectual disability). The rest of the PSS phenotype is still not associated with a specific gene. We report a systematic review of the literature and included two novel cases. Because deletions are highly variable in size, we defined three groups of patients considering the PSS-genes involved. We found 23 full PSS cases (ALX4, EXT2, and PHF21A), 14 cases with EXT2-ALX4, and three with PHF21A only. Among the latter, we describe a novel male child showing developmental delay, café-au-lait spots, liner postnatal overgrowth and West-like epileptic encephalopathy. We suggest PSS cases may have epileptic spasms early in life, and PHF21A is likely to be the causative gene. Given their subtle presentation these may be overlooked and if left untreated could lead to a severe type or deterioration in the developmental plateau. If our hypothesis is correct, a timely therapy may ameliorate PSS phenotype and improve patients’ outcomes. Our analysis also shows PHF21A is a candidate for the overgrowth phenotype
Drug Absorption Modeling as a Tool to Define the Strategy in Clinical Formulation Development
The purpose of this mini review is to discuss the use of physiologically-based drug absorption modeling to guide the formulation development. Following an introduction to drug absorption modeling, this article focuses on the preclinical formulation development. Case studies are presented, where the emphasis is not only the prediction of absolute exposure values, but also their change with altered input values. Sensitivity analysis of technologically relevant parameters, like the drug’s particle size, dose and solubility, is presented as the basis to define the clinical formulation strategy. Taking the concept even one step further, the article shows how the entire design space for drug absorption can be constructed. This most accurate prediction level is mainly foreseen once clinical data is available and an example is provided using mefenamic acid as a model drug. Physiologically-based modeling is expected to be more often used by formulators in the future. It has the potential to become an indispensable tool to guide the formulation development of challenging drugs, which will help minimize both risks and costs of formulation development
Evaluation intégrée des mesures agro-environnementales territorialisées à enjeu "qualité des eaux" sur la période 2007 à 2011 : le projet MAEVEAU
The MAEVEAU project has developed an approach for an integrated assessment of effectiveness of regionalized Agro-Environmental Measures (MAET) intended to preserve water quality in relation to pesticides. This approach investigates the concept of efficiency through a triple analysis: the impact (net effects), the environmental cost-effectiveness and the role of organizational factors in the contracting process. The impact is assessed by a quasi-experimental approach by counterfactuals and examines adaptation of the matching method to the regionalized MAET. Cost-effectiveness analysis is based on integrated modeling spatially distributed coupling the agro-hydrological SWAT model, pesticides pressure indicators and a bio-economic model optimizing gross margin. The effectiveness of organizational factors focuses on transaction costs, the role of collective action and preferences for alternative contracts.La recherche conduite dans le projet MAEVEAU a développé une démarche d'évaluation intégrée de l'efficacité des Mesures Agro-Environnementales Territorialisées (MAET) à enjeu préservation de la qualité de l'eau vis-à -vis des pesticides sur la période 2007 à 2011. La question scientifique traite le concept d'efficacité de la politique en s'appuyant sur une triangulation des approches: une évaluation de l'impact (c'est-à -dire des effets propres de la politique), une évaluation coût-efficacité environnementale et une évaluation du rôle des facteurs organisationnels dans le processus d'adhésion. L'impact est évalué par une approche quasi-expérimentale par contrefactuel et questionne l'adaptation de la méthode du matching à la territorialisation des MAET. L'analyse coût-efficacité s'appuie sur une modélisation intégrée spatialisée couplant modèle agro-hydrologique, indicateurs pesticides spatialisés et optimisation économique des marges brutes. L'efficacité des facteurs organisationnels s'est intéressée aux coûts de transaction, au rôle de l'action collective et aux préférences pour des contrats alternatifs
Orthogonal rotation in PCAMIX
Kiers (1991) considered the orthogonal rotation in PCAMIX, a principal
component method for a mixture of qualitative and quantitative variables.
PCAMIX includes the ordinary principal component analysis (PCA) and multiple
correspondence analysis (MCA) as special cases. In this paper, we give a new
presentation of PCAMIX where the principal components and the squared loadings
are obtained from a Singular Value Decomposition. The loadings of the
quantitative variables and the principal coordinates of the categories of the
qualitative variables are also obtained directly. In this context, we propose a
computationaly efficient procedure for varimax rotation in PCAMIX and a direct
solution for the optimal angle of rotation. A simulation study shows the good
computational behavior of the proposed algorithm. An application on a real data
set illustrates the interest of using rotation in MCA. All source codes are
available in the R package "PCAmixdata"
Long-term outcomes after reduced-intensity conditioning allogeneic stem cell transplantation for low-grade lymphoma: a survey by the French Society of Bone Marrow Graft Transplantation and Cellular Therapy (SFGM-TC)
Clinical spectrum of MTOR-related hypomelanosis of Ito with neurodevelopmental abnormalities
PURPOSE: Hypomelanosis of Ito (HI) is a skin marker of somatic mosaicism. Mosaic MTOR pathogenic variants have been reported
in HI with brain overgrowth. We sought to delineate further the pigmentary skin phenotype and clinical spectrum of
neurodevelopmental manifestations of MTOR-related HI.
METHODS: From two cohorts totaling 71 patients with pigmentary mosaicism, we identified 14 patients with Blaschko-linear and
one with flag-like pigmentation abnormalities, psychomotor impairment or seizures, and a postzygotic MTOR variant in skin. Patient
records, including brain magnetic resonance image (MRI) were reviewed. Immunostaining (n = 3) for melanocyte markers and
ultrastructural studies (n = 2) were performed on skin biopsies.
RESULTS: MTOR variants were present in skin, but absent from blood in half of cases. In a patient (p.[Glu2419Lys] variant),
phosphorylation of p70S6K was constitutively increased. In hypopigmented skin of two patients, we found a decrease in stage 4
melanosomes in melanocytes and keratinocytes. Most patients (80%) had macrocephaly or (hemi)megalencephaly on MRI.
CONCLUSION: MTOR-related HI is a recognizable neurocutaneous phenotype of patterned dyspigmentation, epilepsy, intellectual
deficiency, and brain overgrowth, and a distinct subtype of hypomelanosis related to somatic mosaicism. Hypopigmentation may
be due to a defect in melanogenesis, through mTORC1 activation, similar to hypochromic patches in tuberous sclerosis complex
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