Search results for " Trees"
showing 10 items of 214 documents
Predicting the environmental suitability for onchocerciasis in Africa as an aid to elimination planning
2021
Recent evidence suggests that, in some foci, elimination of onchocerciasis from Africa may be feasible with mass drug administration (MDA) of ivermectin. To achieve continental elimination of transmission, mapping surveys will need to be conducted across all implementation units (IUs) for which endemicity status is currently unknown. Using boosted regression tree models with optimised hyperparameter selection, we estimated environmental suitability for onchocerciasis at the 5 × 5-km resolution across Africa. In order to classify IUs that include locations that are environmentally suitable, we used receiver operating characteristic (ROC) analysis to identify an optimal threshold for suitabil…
Does an optimal therapeutic sequence exist in advanced non-small cell lung cancer?
2008
A growing percentage of patients affected by advanced non-small cell lung cancer who progressed after first-line chemotherapy still have a good performance status and require second-line treatment.An overview of the state of the art of second-line therapeutic options is presented.The scope of the review is to give an update on the therapeutic options currently available for the second-line treatment of patients with advanced non-small cell lung cancer.Among chemotherapeutic drugs docetaxel and pemetrexed have been approved for second-line treatment of advanced non-small cell lung cancer. Although the drugs are equiactive in terms of response rate and survival parameters the latter has a cle…
Hundreds of nuclear and plastid loci yield novel insights into orchid relationships.
2021
Pérez-Escobar, Oscar Alejandro, Dodsworth, Steven, Bogarín, Diego, Bellot, Sidonie, Balbuena, Juan A, Schley, Rowan J, Kikuchi, Izai A, Morris, Sarah K, Epitawalage, Niroshini, Cowan, Robyn, Maurin, Olivier, Zuntini, Alexandre, Arias, Tatiana, Serna-Sánchez, Alejandra, Gravendeel, Barbara, Torres Jimenez, Maria Fernanda, Nargar, Katharina, Chomicki, Guillaume, Chase, Mark W, Leitch, Ilia J, Forest, Félix, Baker, William J (2021): Hundreds of nuclear and plastid loci yield novel insights into orchid relationships. American journal of botany 108 (7): 1166-1180, DOI: http://doi.org/10.5281/zenodo.7778176
Comparing Boosting and Bagging for Decision Trees of Rankings
2021
AbstractDecision tree learning is among the most popular and most traditional families of machine learning algorithms. While these techniques excel in being quite intuitive and interpretable, they also suffer from instability: small perturbations in the training data may result in big changes in the predictions. The so-called ensemble methods combine the output of multiple trees, which makes the decision more reliable and stable. They have been primarily applied to numeric prediction problems and to classification tasks. In the last years, some attempts to extend the ensemble methods to ordinal data can be found in the literature, but no concrete methodology has been provided for preference…
Diversity and Evolution of papillomaviruses
2017
1.1. Introducción Con el fin de averiguar las causas de las devastadoras epidemias de finales del siglo XIX, se llevaron a cabo diferentes estudios que dieron como resultado la identificación de unos nuevos agentes infecciosos, para los que se acuñó el nombre de “virus”. Desde entonces el descubrimiento de nuevos virus ha sido incesante, lo que llevó, en los años 70, a la creación de un organismo encargado de desarrollar, refinar y mantener la clasificación taxonómica de los virus, el Comité Internacional de Taxonomía Viral (ICTV), en el seno de la Unión Internacional de Sociedades Microbiológicas (IUMS). En 2014 este organismo había reconocido 3.186 especies virales pertenecientes a 104 fa…
Treed Gaussian Process Regression for Solving Offline Data-Driven Continuous Multiobjective Optimization Problems
2023
Abstract For offline data-driven multiobjective optimization problems (MOPs), no new data is available during the optimization process. Approximation models (or surrogates) are first built using the provided offline data and an optimizer, e.g. a multiobjective evolutionary algorithm, can then be utilized to find Pareto optimal solutions to the problem with surrogates as objective functions. In contrast to online data-driven MOPs, these surrogates cannot be updated with new data and, hence, the approximation accuracy cannot be improved by considering new data during the optimization process. Gaussian process regression (GPR) models are widely used as surrogates because of their ability to pr…
Cost-Effectiveness Analysis: Stress Ulcer Bleeding Prophylaxis with Proton Pump Inhibitors, H2 Receptor Antagonists
2012
Abstract Objectives Proton pump inhibitors (PPIs) and H2-receptor antagonists (H2RAs) present varying pharmacological efficacy in preventing stress ulcer bleeding (SUB) in intensive care units. The literature also reports disparate rates of ventilator-assisted pneumonia (VAP) as side effects of these treatments. We compared the cost-effectiveness of these two prophylactic pharmacological options. Methods We constructed a decision tree with a 60-day time horizon for patients at high risk for developing SUB, receiving either PPIs or H2RAs. For each treatment strategy, patients could be in one of three states of health: SUB, VAP, or no complication. Contemporary, clinically relevant probabilit…
A tool for filtering information in complex systems
2005
We introduce a technique to filter out complex data-sets by extracting a subgraph of representative links. Such a filtering can be tuned up to any desired level by controlling the genus of the resulting graph. We show that this technique is especially suitable for correlation based graphs giving filtered graphs which preserve the hierarchical organization of the minimum spanning tree but containing a larger amount of information in their internal structure. In particular in the case of planar filtered graphs (genus equal to 0) triangular loops and 4 element cliques are formed. The application of this filtering procedure to 100 stocks in the USA equity markets shows that such loops and cliqu…
Evolution of correlation structure of industrial indices of U.S. equity markets
2013
We investigate the dynamics of correlations present between pairs of industry indices of US stocks traded in US markets by studying correlation based networks and spectral properties of the correlation matrix. The study is performed by using 49 industry index time series computed by K. French and E. Fama during the time period from July 1969 to December 2011 that is spanning more than 40 years. We show that the correlation between industry indices presents both a fast and a slow dynamics. The slow dynamics has a time scale longer than five years showing that a different degree of diversification of the investment is possible in different periods of time. On top to this slow dynamics, we als…
Forced Flowering in Mandarin Trees Under Phytotron Conditions
2019
[EN] Phytotron has been widely used to assess the effect of numerous parameters on the development of many species. However, less information is available on how to achieve fast profuse flowering in young fruit trees with this plant growth chamber. This study aimed to outline the design and performance of a fast clear methodology to force flowering in young mandarin trees (cv. Nova and cv. Clemenules) and to analyze the influence of induction intensity on inflorescence type. The combination of a short water stress period with simulated spring conditions (day 13 h, 22 °C, night 11 h, 12 °C) in the phytotron allowed flowers to be obtained only after 68-72 days from the time the experiment beg…