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19 results on '"Castro, L. N."'

2. An Overview of Artificial Immune Systems

Author

Timmis, J., Knight, T., de Castro, L. N., Hart, E., Rozenberg, G., editor, Bäck, Th., editor, Eiben, A. E., editor, Kok, J. N., editor, Spaink, H. P., editor, Paton, Ray, editor, Bolouri, Hamid, editor, Holcombe, Mike, editor, Parish, J. Howard, editor, and Tateson, Richard, editor

Published
2004
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4. The glauconitic levels of the Salamanca Formation, Chubut : its agronomic effectiveness as a potassium fertilizer alternative

Author

Castro, L. N., Scasso, R. A., Branzini, A., Zubillaga, M. S., Fazio, A. M., Tourn, S. M., and Zubillaga, M. M.

Subjects
GLAUCONITIC SANDSTONES, SANDSTONE, GLAUCONITE, ARGENTINA, FELDSPAR, LEACHING, POTASSIUM, CHUBUT, POTASSIUM ALTERNATIVE SOURCES, BIOASSAY, FERTILIZER APPLICATION, IRRIGATION, SALAMANCA FORMATION, AGRONOMY, SOIL REMEDIATION, POTASSIUM FERTILIZER
Abstract

391-398 The Maastrichtian-Early Palaeocene Salamanca Formation and equivalent marine sequences show several glaucony levels, which could be used as a source of potassium and could partially replace current fertilizer requirements met from import. First agronomic assays are shown comparing the efficiency of greensands (GL) with a traditional potassium fertilizer (KCl). Prospection and sampling took place in the heads of Rio Chico to east of Lago Colhué Huapi, Chubut, where glauconitic levels thickness reach to 20m. This research was separated in phases: phase 1, prospection, sampling, and sedimentological and chemical routine analyses, phase 2a, concentration and ore treatment assays, and phase 2b, agronomic assays. This last phase, was done in culture chamber, with 125 um and 250 um fractions (2,85 and 2,82 percent K 2O respectively) and KCl. Varying the dose, seven treatments were completed. In successive harvests (four in total) was observed that GL1 and GL2 (125), did not present a significantly differential behavior with the control. Both treatments of GL 250 um showed major accumulated biomass, overcoming the control in 44 and 60 percent respectively. As conclusion, better results were obtained by 250 um overcoming even to the KCl fertilization. Probably the major participation of K feldspars in the 125 um and fast leaching of K in this fraction during successive irrigations of soil would originate the minor observed yield. The great areal extension of the Salamanca Formation and the continuity of the glauconitic levels encourage continuing the evaluation as fertilizer or amendment.

Published
2010

6. Geochemistry of rare earth elements in early-diagenetic miocene phosphatic concretions of Patagonia, Argentina: Phosphogenetic implications

Author

Fazio, A. M., Scasso, R. A., Castro, L. N., Carey, S., Fazio, A. M., Scasso, R. A., Castro, L. N., and Carey, S.

Abstract

Phosphatic concretions in the Early Miocene, shallow marine, clastic deposits of the Gaiman Formation (Gaiman Fm.) show typical major element ratios, rare earth element (REE) patterns, and total REE contents. These characteristics are similar within different stratigraphic levels and geographic locations of the unit in central-north Patagonia, Argentina and suggest a common process for the origin of the concretions. Major element oxides in concretions are grouped into a "clastic" group (Si, Al, Ti, K and Fe), that mostly corresponds to the silicates in the terrigenous fraction, and an "authigenic" group (P, Ca and total REEs), that corresponds to authigenic francolite and calcite. Mn is the only element that exhibits a separate behavior, most likely because of its high mobility in seawater. Major element ratios in host shales are similar to those of the clastic fraction within the concretions and coquinas. Concretions are slightly depleted in LREEs and slightly enriched in HREEs in comparison to shales and display a weak negative Ce anomaly. Their La/Yb and La/Sm ratios indicate REEs incorporation from pore water without strong postdepositional recrystallization or strong adsorption. Y anomalies and La/Nd ratios in concretions are equivalent to seawater or slightly lower, suggesting that Gaiman concretions did not undergo intense diagenesis, but they were probably formed from phosphatic solutions impoverished in Y and La as a result of REEs release to solution from organic complexes in the early diagenesis. Flat, linear REE patterns also support an early-diagenetic origin for the concretions, via quantitative precipitation of phosphate from oxic-suboxic pore waters. Water circulation through burrows at the Miocene seawater-sediment interface improved ion diffusion and pore water renewal in the sediments, allowing the development of a widened early-diagenetic oxic-suboxic zone and the precipitation of phosphate with a homogeneous REE pattern. © 2007 Elsevier Ltd. All

Published
2007

7. POSTER SESSION 2: MARKERS, PSYCHIATRY AND TREATMENT * MARKERS * P49 * BIOMARKERS DEMONSTRATE INCREASED CONSUMPTION BUT NOT ABUSE OF ETHANOL IN ESSENTIAL TREMOR

Author

Ulmanova, O., primary, Zima, T., additional, Vinopalova, M., additional, Ruzicka, E., additional, Ho, A. M., additional, Daglish, M., additional, Dodd, P. R., additional, Stadlin, A., additional, Nakamura-Palacios, E. M., additional, Benevides, M. C. A., additional, Zago-Gomes, M. P., additional, Oliveira, R. W. D., additional, Vasconcellos, V. F., additional, Castro, L. N. P., additional, Silva, M. C., additional, Ramos, P. A., additional, Fregni, F., additional, Meinhardt, M., additional, Hansson, A. C., additional, Perreau-Lenz, S., additional, Drescher, K. U., additional, Heilig, M., additional, Spanagel, R., additional, Sommer, W. H., additional, Pierrefiche, O., additional, Kervern, M., additional, Bellanguez, A., additional, Naassila, M., additional, Smyth, D. J., additional, Phedina, K., additional, Zimatkin, S., additional, Suchankova, P., additional, Engel, J. A., additional, Landgren, S., additional, Jerlhag, E., additional, Friedrich, F., additional, Grunberger, J., additional, Frottier, P., additional, Stohr, H., additional, Vyssoki, B., additional, Walter, H., additional, Lesch, O., additional, Ciolli, P., additional, Ciccarone, F., additional, Scamporrino, M., additional, Solombrino, S., additional, Cereatti, F., additional, Fiorentino, D., additional, Rotondo, C., additional, and Ceccanti, M., additional

Published
2011
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15. Clustering Gene-Expression Data: A Hybrid Approach that Iterates Between k-Means and Evolutionary Search.

Author

Kacprzyk, Janusz, Abraham, Ajith, Grosan, Crina, Ishibuchi, Hisao, Hruschka, E. R., de Castro, L. N., and Campello, R. J. G. B.

Abstract

Clustering genes based on their expression profiles is usually the first step in geneexpression data analysis. Among the many algorithms that can be applied to gene clustering, the k-means algorithm is one of the most popular techniques. This is mainly due to its ease of comprehension, implementation, and interpretation of the results. However, k-means suffers from some problems, such as the need to define a priori the number of clusters (k) and the possibility of getting trapped into local optimal solutions. Evolutionary algorithms for clustering, by contrast, are known for being capable of performing broad searches over the space of possible solutions and can be used to automatically estimate the number of clusters. This work elaborates on an evolutionary algorithm specially designed to solve clustering problems and shows how it can be used to optimize the k-means algorithm. The performance of the resultant hybrid approach is illustrated by means of experiments in several bioinformatics datasets with multiple measurements, which are expected to yield more accurate and more stable clusters. Two different measures (Euclidean and Pearson) are employed for computing (dis)similarities between genes. A review of the use of evolutionary algorithms for gene-expression data processing is also included. Key words: Evolutionary algorithms, k-means algorithm, Clustering, Bioinformatics. [ABSTRACT FROM AUTHOR]

Published
2007
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18. Automatic determination of radial basis functions: an immunity-based approach.

Author

de Castro LN and Von Zuben FJ

Subjects
Artificial Intelligence, Automation, Immunity, Least-Squares Analysis, Models, Immunological, Random Allocation, Algorithms, Computer Simulation, Neural Networks, Computer
Abstract

The appropriate operation of a radial basis function (RBF) neural network depends mainly upon an adequate choice of the parameters of its basis functions. The simplest approach to train an RBF network is to assume fixed radial basis functions defining the activation of the hidden units. Once the RBF parameters are fixed, the optimal set of output weights can be determined straightforwardly by using a linear least squares algorithm, which generally means reduction in the learning time as compared to the determination of all RBF network parameters using supervised learning. The main drawback of this strategy is the requirement of an efficient algorithm to determine the number, position, and dispersion of the RBFs. The approach proposed here is inspired by models derived from the vertebrate immune system, that will be shown to perform unsupervised cluster analysis. The algorithm is introduced and its performance is compared to that of the random, k-means center selection procedures and other results from the literature. By automatically defining the number of RBF centers, their positions and dispersions, the proposed method leads to parsimonious solutions. Simulation results are reported concerning regression and classification problems.

Published
2001
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