Sergio F. Martínez y Xiang Huang. 2015. Hacia una Filosofía de la Ciencia Centrada en Prácticas

Review of Sergio F. Martínez y Xiang Huang. 2015. Hacia una Filosofía de la Ciencia Centrada en Práctica

Implementing a Loosely-Coupled Integrated Assessment Model in the Pegasus Workflow Management System

Integrated assessment models (IAMs) are commonly used to explore the interactions between different modeled components of socio-environmental systems (SES). Most IAMs are built in a tightly-coupled framework so that the complex interactions between the models can be efficiently implemented within the framework in a straightforward manner. However, tightly-coupled frameworks make it more difficult to change individual models within the IAM because of the high level of integration between the models. Prioritizing flexibility over computational efficiency, the IAM presented here is built using a loosely-coupled framework and implemented in the Pegasus Workflow Management System. The modular nature of loosely-coupled systems allows each component model within the IAM to be easily exchanged for another component model from the same domain assuming each provides the same input / output interface. This flexibility allows researchers to experiment with different models for each SES component and facilitates smoother upgrades between each version of the independently developed component models

Groundwater fluctuations induced by ecological water conveyance in the lower Tarim River, Xinjiang, China

Data from 40 monitoring wells across 9 sections of the lower Tarim River from 2000 to 2006 were analyzed to investigate the relationship between the transmission loss per unit river length and the change in groundwater depth. The relationship between the rise of the groundwater table (y) and the distance from the main river reach (x) was then assessed through regression analysis. We concluded that the maximum affected area was 1933 m away from the main river reach in the Alagan section, and the minimum affected area was 576 m away in the Kaogan section. In addition, after 8 water deliveries, the volume for recharging the groundwater was 78 248.7 x 10(4) m(3). Using the Yingsu section as an example, we found that the volume for recharging the groundwater decreased with additional periods of delivery except after the second and sixth water delivery The results revealed that the beneficial effect of an ecological water conveyance project on the ecosystem in the lower Tarim River is a long-term process. These findings may be useful for guiding studies on instream flow requirements and provide a scientific basis for implementing similar ecological projects in other areas. (C) 2009 Elsevier Ltd. All rights reserved

Superradiantly stable non-extremal Reissner-Nordstrom black holes

The superradiant stability is investigated for non-extremal Reissner-Nordstrom black hole. We use an algebraic method to demonstrate that all non-extremal Reissner-Nordstrom black holes are superradiantly stable against a charged massive scalar perturbation. This improves the results obtained before for non-extremal Reissner-Nordstrom black holes

Viabilidad de un PLL (Phase-Locked Loop) para la extracción de componentes sinusoidales en series de datos financieros

Las series de datos financieros (SP500, Dow Jones, Nasdaq, etc) se pueden analizar aplicando técnicas de procesado digital de señales con objeto de extraer cierta información. En los últimos años ha aparecido una nueva técnica que permite descomponer una señal en sus cíclicas, la transformada de Hilbert-Huang. Cuando se aplica esta transformada a una serie de datos financieros aparecen separadas varias componentes sinusoidales y una componente tendencial. Tomando como referencia cualquiera de las componentes sinusoidales y aplicando simples señales de trading sobre la misma es factible obtener rentabilidades positivas de forma continuada. Sin embargo, estas señales están generadas a posteriori. Con objeto de obtener estas señales en tiempo real (online) se propone la utilización de un PLL (Phase- Locked Loop) para tener una referencia enganchada en fase en cualquiera de las componentes sinusoidales, obtenidas previamente con la transformada de Hilbert- Huang, y a partir de ella realizar una estrategia de inversión