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Institution

Simón Bolívar University

EducationCaracas, Venezuela
About: Simón Bolívar University is a education organization based out in Caracas, Venezuela. It is known for research contribution in the topics: Population & Crystallization. The organization has 5912 authors who have published 8294 publications receiving 126152 citations.


Papers
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Journal ArticleDOI
TL;DR: In this article, the strength characteristics of geopolymer self-compacting concrete made by addition of mineral admixtures, have been modelled with both genetic programming (GEP) and the artificial neural networks (ANN) techniques.
Abstract: There has been a persistent drive for sustainable development in the concrete industry While there are series of encouraging experimental research outputs, yet the research field requires a standard framework for the material development In this study, the strength characteristics of geopolymer self-compacting concrete made by addition of mineral admixtures, have been modelled with both genetic programming (GEP) and the artificial neural networks (ANN) techniques The study adopts a 12M sodium hydroxide and sodium silicate alkaline solution of ratio to fly ash at 033 for geopolymer reaction In addition to the conventional material (river sand), fly ash was partially replaced with silica fume and granulated blast furnace slag Various properties of the concrete, filler ability and passing ability of fresh mixtures, and compressive, split-tensile and flexural strength of hardened concrete were determined The model development involved using raw materials and fresh mix properties as predictors, and strength properties as response Results shows that the use of the admixtures enhanced both the fresh and hardened properties of the concrete Both GEP and ANN methods exhibited good prediction of the experimental data, with minimal errors However, GEP models can be preferred as simple equations are developed from the process, while ANN is only a predictor

91 citations

Journal ArticleDOI
TL;DR: In this article, the authors study the problem of the emergence of cooperation in the spatial Prisoner's Dilemma and show that if a fixed-amount reward is established for cooperators to share, a single cooperator can invade a population of defectors and form structures that are resilient to re-invasion even if the reward mechanism is turned off.

91 citations

Journal ArticleDOI
TL;DR: A Markov chain method is introduced that considers teams made up of players with different abilities and which is not restricted to a given model for runner advancement, and can use any reasonable deterministic model forRunner advancement when sufficiently detailed data are not available.
Abstract: Most earlier mathematical studies of baseball required particular models for advancing runners based on a small set of offensive possibilities. Other efforts considered only teams with players of identical ability. We introduce a Markov chain method that considers teams made up of players with different abilities and which is not restricted to a given model for runner advancement. Our method is limited only by the available data and can use any reasonable deterministic model for runner advancement when sufficiently detailed data are not available. Furthermore, our approach may be adapted to include the effects of pitching and defensive ability in a straightforward way. We apply our method to find optimal batting orders, run distributions per half inning and per game, and the expected number of games a team should win. We also describe the application of our method to test whether a particular trade would benefit a team.

90 citations

Journal ArticleDOI
TL;DR: Many chemical remagnetization mechanisms have been proposed, including those associated with chemical alteration by a number of different fluids (e.g., orogenic, weathering, mineralizing, hydrocarbons) and burial diagenetic processes as mentioned in this paper.
Abstract: Remagnetization is a common phenomenon in rocks, and developing a greater understanding of its mechanisms has several benefits. Acquisition of a secondary magnetization is usually tangible evidence of a diagenetic or thermal event, which can be dated using palaeomagnetic techniques. This is important because the timing of diagenetic and thermal events is commonly difficult to determine. Remagnetization can also obscure primary magnetizations and a better understanding of remagnetization could improve our ability to uncover primary magnetizations. Many chemical remagnetization mechanisms have been proposed, including those associated with chemical alteration by a number of different fluids (e.g. orogenic, weathering, mineralizing, hydrocarbons) and burial diagenetic processes (e.g. clay diagenesis, maturation of organic matter). This book contains case studies and review articles that focus on remagnetization, chemical remagnetization mechanisms, and magnetic changes associated with chemical alteration by hydrocarbons.

90 citations

Journal ArticleDOI
TL;DR: The Global Coral Reef Monitoring Network has been the foundation for global reporting on coral reefs for two decades, and is entering into a new phase with improved operational and data standards incorporating the Essential Ocean Variables (EOVs) (www.goosocean.org/eov) and Framework for Ocean Observerving developed by the Global Ocean Observing System as discussed by the authors.
Abstract: Coral reefs are exceptionally biodiverse and human dependence on their ecosystem services is high. Reefs experience significant direct and indirect anthropogenic pressures, and provide a sensitive indicator of coastal ocean health, climate change, and ocean acidification, with associated implications for society. Monitoring coral reef status and trends is essential to better inform science, management and policy, but the projected collapse of reef systems within a few decades makes the provision of accurate and actionable monitoring data urgent. The Global Coral Reef Monitoring Network has been the foundation for global reporting on coral reefs for two decades, and is entering into a new phase with improved operational and data standards incorporating the Essential Ocean Variables (EOVs) (www.goosocean.org/eov) and Framework for Ocean Observing developed by the Global Ocean Observing System. Three EOVs provide a robust description of reef health: hard coral cover and composition, macro-algal canopy cover, and fish diversity and abundance. A data quality model based on comprehensive metadata has been designed to facilitate maximum global coverage of coral reef data, and tangible steps to track capacity building. Improved monitoring of events such as mass bleaching and disease outbreaks, citizen science, and socio-economic monitoring have the potential to greatly improve the relevance of monitoring to managers and stakeholders, and to address the complex and multi-dimensional interactions between reefs and people. A new generation of autonomous vehicles (underwater, surface, and aerial) and satellites are set to revolutionize and vastly expand our understanding of coral reefs. Promising approaches include Structure from Motion image processing, and acoustic techniques. Across all systems, curation of data in linked and open online databases, with an open data culture to maximize benefits from data integration, and empowering users to take action, are priorities. Action in the next decade will be essential to mitigate the impacts on coral reefs from warming temperatures, through local management and informing national and international obligations, particularly in the context of the Sustainable Development Goals, climate action, and the role of coral reefs as a global indicator. Mobilizing data to help drive the needed behavior change is a top priority for coral reef observing systems.

90 citations


Authors

Showing all 5925 results

NameH-indexPapersCitations
Franco Nori114111763808
Ignacio Rodriguez-Iturbe9633432283
Ian W. Hamley7846925800
Francisco Zaera7343219907
Thomas G. Habetler7339520725
Douglas L. Jones7051221596
I. Taboada6634613528
Enrique Herrero6424211653
Rudi Studer6026819876
Alejandro J. Müller5842012410
David Padua5824311155
Rudolf Jaffé5818210268
Luis Balicas5732814114
Volker Abetz5538611583
Ananias A. Escalante511608866
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20232
202220
2021286
2020384
2019340
2018312