Creation of new intergeneric and interspecific somatic hybrids: An objective of the 6th PCRD european project 'CIBEWU' to face the mediterranean citrus rootstock challenge : [P2]

The predominance of sour orange rootstock in the Southern and Eastern part of the Mediterranean Basin is presently threatened by the spread of Citrus Tristeza Virus (CfV) and the dispersion of its main vector Toxoptera citricida. As a result the search for alternative rootstocks resistant to CTV and standing other constraints such as drough, alcalinity, salinity, phytophthora and nematods problems is now considered an urgent priority. Complementary genitors should be found in citrus germplasm to combine the desired traits particularly between Ponciros or trifoliate hybrids (citrange. citrumello) for resistances to pest and diseases and Citrus species for abiotic tolerances. The creation of somatic hybrids allows cumulating all dominant genes for tolerance to biotic and abiotic factors of the two parents, irrespective to their heterozygozity level. Moreover tetraploid level per se seems to irnprove toterances to salt and osmotic stress. Thus, the creation of new intergenetic and interspecific somatic hybrids has been included as one of the objectives in the 6th PCRD European Project 'ClBEWU' aiming to face the Mediterranean citrus rootstock challenge. New embryogenic callus lines to be used for somatic hybridization have been induced by INRAM (Morocco), lNRAT (Tunisia), Cukurova University (Turkey), IVIA (Spain) and CIRAD (France). Somatic hybridizations have been realized at CIRAD and IVIA with special emphasis in intergeneric (Citrus + Poncirus) combinations. Plants have been regenerated from 6 intergeneric and 1 interspecific combinations. Analysis of ploidy by flow cytometry and SSR markers studies are going on. The obtainment of interesting new tetraploid somatic hybrids has already been confirmed for 4 intergeneric (CIRAD: C. reshni + C35 citrange, C. sinensis + P. trifoliata; C. sinensis + C35 citrange; IVIA: C. macrophylla + Carrizo citrange) combinations and 1 interspecific combinations (IVIA: C. aurantium + C. taiwanica). Diploid cybrids with trifoliate hybrid nucleus and C. deliciosa or C. macrophylfa mitochondria have also been identified for 3 intergeneric combinations (CIR.AD: C. deliciosa + 4475 citrumello; C. deliciosa + C35 citrange; IVIA: C. macrophylla + Carrizo citrange). Methodological transfer to lNRAM (Morocco), INRAT (Tunisia) and Cukurova University (Turkey) has been done. (Texte intégral

Clustering Via Nonparametric Density Estimation: the R Package pdfCluster

The R package pdfCluster performs cluster analysis based on a nonparametric estimate of the density of the observed variables. After summarizing the main aspects of the methodology, we describe the features and the usage of the package, and finally illustrate its working with the aid of two datasets

Combined nitrogen and phosphorus removal from wastewaters

Yhdistetty typen ja fosforin poisto jätevesist

Toxicity of three comercial tannins to the nuisance invasive species Limnoperna fortunei (Dunker, 1857): implications for control

Adding biocides to water is one strategy to control macrofouling organisms. A natural biocide that helps to prevent/control macrofouling of Limnoperna fortunei (Dunker, 1857) on human installations is one way to minimize environmental impacts of different control strategies. Laboratory tests were carried out to evaluate effects of three commercial tannis preparations (ECOTEC®-UA, ECOTEC®-L and ECOTEC®-MC) on the survival of two life-history stages (larvae and adults) of L. fortunei. In addition tests were performed on two non-target species, a crustacean Daphnia magna and a plant Lactuca sativa, to evaluate effects of these tannins on the aquatic environment. The larvae of L. fortunei were more vulnerable to the concentrations of the three tannins than adults. The two nontarget species were not affected at concentrations that were effective for larvae. These results suggest that these products could be used as biocides to control macrofouling caused by L. fortunei.Fil: Pereyra, Patricio Javier. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bulus Rossini, Gustavo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Química. Centro de Investigaciones del Medio Ambiente; ArgentinaFil: Darrigran, Gustavo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentin

Primary production of phytoplankton in the three types of Amazonian waters. V. Some investigations on the phytoplankton and its primary productivity in the clear water of the lower Rio Tapajós (Pará, Brazil)

Four limnological investigations were conducted in different seasons of the years 1968 and 1969 at the lower reaches of the Rio Tapajóz. The physical and chemical parameters generally correspond with earlier findings of other authors. Midriver areas show no stratification of the water body. In certain reaches of the river, distinct increases of pH-values temporarily occur due to strong phytoplankton activity. A few species of cyanophyceae and diatomeae make up the vast majority of phytoplankton in terms of nu,bers. Chlorophyceae, desmidiaceae, and other algae are characterized by high species variety but only occur in low or moderate densities. Despite of the low nutrient concentrations encountered, phytoplankton production is high, which can be attributed to the excellent light conditions in the river. The net production of 2.4 g C/m²/d exceeds by far production rates from várzea-lakes, although production densities are lower. A mighty productive zone in combination with extremely fast turn over rates male this unexpected high production per unit area possible. The shortest C turn over time of all samples was 0.3 days. Phytoplankton net production amounts to a calculated 5 t C hectare and year. Derived from primary production data, a theoretical fish production of 100 kg/ha/year can be estimated, which would allow yearly catches of at least 10 to 20 kg per hectare for human consumption without provocing ecological disturbances

Limiting Network Size within Finite Bounds for Optimization

Largest theoretical contribution to Neural Networks comes from VC Dimension which characterizes the sample complexity of classification model in a probabilistic view and are widely used to study the generalization error. So far in the literature the VC Dimension has only been used to approximate the generalization error bounds on different Neural Network architectures. VC Dimension has not yet been implicitly or explicitly stated to fix the network size which is important as the wrong configuration could lead to high computation effort in training and leads to over fitting. So there is a need to bound these units so that task can be computed with only sufficient number of parameters. For binary classification tasks shallow networks are used as they have universal approximation property and it is enough to size the hidden layer width for such networks. The paper brings out a theoretical justification on required attribute size and its corresponding hidden layer dimension for a given sample set that gives an optimal binary classification results with minimum training complexity in a single layered feed forward network framework. The paper also establishes proof on the existence of bounds on the width of the hidden layer and its range subjected to certain conditions. Findings in this paper are experimentally analyzed on three different dataset using Mathlab 2018 (b) software

Irrelevant feature and rule removal for structural associative classification

In the classification task, the presence of irrelevant features can significantly degrade the performance of classification algorithms,in terms of additional processing time, more complex models and the likelihood that the models have poor generalization power due to the over fitting problem.Practical applications of association rule mining often suffer from overwhelming number of rules that are generated, many of which are not interesting or not useful for the application in question.Removing rules comprised of irrelevant features can significantly improve the overall performance.In this paper, we explore and compare the use of a feature selection measure to filter out unnecessary and irrelevant features/attributes prior to association rules generation.The experiments are performed using a number of real-world datasets that represent diverse characteristics of data items.Empirical results confirm that by utilizing feature subset selection prior to association rule generation, a large number of rules with irrelevant features can be eliminated.More importantly, the results reveal that removing rules that hold irrelevant features improve the accuracy rate and capability to retain the rule coverage rate of structural associative association

A Mixture of SDB Skew-t Factor Analyzers

Mixtures of skew-t distributions offer a flexible choice for model-based clustering. A mixture model of this sort can be implemented using a variety of formulations of the skew-t distribution. Herein we develop a mixture of skew-t factor analyzers model for clustering of high-dimensional data using a flexible formulation of the skew-t distribution. Methodological details of our approach, which represents an extension of the mixture of factor analyzers model to a flexible skew-t distribution, are outlined and details of parameter estimation are provided. Clustering results are illustrated and compared to an alternative formulation of the mixture of skew-t factor analyzers model as well as the mixture of factor analyzers model

17. Issues for Nuclear Power Plants Steam Generators

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