Preliminary results of research cruises carried out by IEO on the High Seas of the SW Atlantic (2008-2009), regarding cephalopod target species (Illex argentinus and Loligo gahi)

In March 2008 the Instituto Español de Oceanografía (IEO) through its Oceanographic Centre in Vigo (IEO-COV) initiated a historical series of research cruises aiming the assessment of the main commercial stocks on the High Seas (HS) of the SW Atlantic, including the study of two cephalopod species of important commercial interest, Argentine short-fin squid (Illex argentinus) and Patagonian squid (Loligo gahi). This working document presents a brief description of the methodology used in the cruises and preliminary results concerning CPUE by depth strata and geographical distribution of both mentioned species

NeuralSens: Sensitivity Analysis of Neural Networks

Neural networks are important tools for data-intensive analysis and are commonly applied to model non-linear relationships between dependent and independent variables. However, neural networks are usually seen as "black boxes" that offer minimal information about how the input variables are used to predict the response in a fitted model. This article describes the \pkg{NeuralSens} package that can be used to perform sensitivity analysis of neural networks using the partial derivatives method. Functions in the package can be used to obtain the sensitivities of the output with respect to the input variables, evaluate variable importance based on sensitivity measures and characterize relationships between input and output variables. Methods to calculate sensitivities are provided for objects from common neural network packages in \proglang{R}, including \pkg{neuralnet}, \pkg{nnet}, \pkg{RSNNS}, \pkg{h2o}, \pkg{neural}, \pkg{forecast} and \pkg{caret}. The article presents an overview of the techniques for obtaining information from neural network models, a theoretical foundation of how are calculated the partial derivatives of the output with respect to the inputs of a multi-layer perceptron model, a description of the package structure and functions, and applied examples to compare \pkg{NeuralSens} functions with analogous functions from other available \proglang{R} packages.Comment: 28 pages, 12 figures, submitted to Journal of Statistical Software (JSS) https://www.jstatsoft.org/inde

Analysis of cephalopods’ abundance indices in the Southwest Atlantic fisheries. 2003-2008

This working document presents a brief analysis of the spatio-temporal variability of abundance indices of cephalopods taken through the observers’ program of the IEO in the Southwest Atlantic between 2003 and 2008 paying particular attention to the High Seas (HS) are

A branched covering of degree 22 of the sphere with a completely invariant indecomposable continuum

We construct a branched covering of degree $2$ of the sphere $S^2$ having a completely invariant indecomposable continuum $K$. The existence of such an object is not known for rational maps of the sphere