Generalized Proportional Integral Control for an Unmanned Quadrotor System

In this article, a generalized proportional integral (GPI) control approach is presented for regulation and trajectory tracking problems in a nonlinear, multivariable quadrotor system model. In the feedback control law, no asymptotic observers or time discretizations are needed in the feedback loop. The GPI controller guarantees the asymptotically and exponentially stable behaviour of the controlled quadrotor position and orientation, as well as the possibilities of carrying out trajectory tracking tasks. The simulation results presented in the paper show that the proposed method exhibits very good stabilization and tracking performance in the presence of atmospheric disturbances and noise measurements

Advance of the design of a computer program for Macroeconomic´s Equilibria teaching

Los modelos macroeconómicos de equilibrio general son una herramienta básica para comprender el funcionamiento de la economía, como se relacionan las principales variables macroeconómicas y el efecto final de las políticas económicas. La enseñanza de estos modelos se realiza fundamentalmente mediante un sistema de ecuaciones matemáticas y en el uso de gráficos concatenados que representan los diversos mercados que intervienen en la economía. Sin embargo, el modo en que estos gráficos son tradicionalmente enseñados no permite al alumno comprender fácilmente el modo en que éstos se relacionan y ver los cambios que se producen en las curvas. El programa de simulación “Equilibrios Macroeconómicos” permite superar estas dificultades ya que los alumnos pueden visualizar fácilmente los cambios en las curvas cuando los parámetros del modelo varían. Ello permite asociar los cambios de dichos valores, a los efectos económicos derivados de los mismos y comprender los efectos finales de las políticas económicas.General equilibrium macroeconomic models are a basic tool for understanding the functioning of the economy, how the main macroeconomic variables are related to and the final effect of economic policies. Teaching of these models is essentially done through a system of mathematical equations and through the use of concatenated graphs which represent the markets involved in the economy. However, the way these graphs are traditionally taught does not allow the learner to easily understand how they are related and visualise changes in the curves. The simulation program "macroeconomic equilibrium" overcomes these difficulties because, through it, the students can easily visualise the changes in these curves when the model’s parameter values are modified. This allows to associate changes in these values with the economic effects and so to understand the final effects of economic policies

Multi-criteria decision modelling for environmental assessment. An estimation of Total Economic Value in protected natural areas.

The conceptualization of Total Economic Value (TEV) associated with protected natural areas necessarily requires an analytical reordering that ensures a simultaneous incorporation of natural, social and economic components. Based on this purpose, the present paper uses a multi-criteria decision modeling for the economic valuation of environmental goods and services (EGS) in the Viñales National Park (PNV) based on a combination of methods such as the Analytic Hierarchy Process (AHP) and the Goal Programming (GP) with other traditional such as the income updating method. The proposed procedure allowed estimate an indicator of Total Economic Value (TEV) and its different components: Direct Use Value (DUV), Indirect Use Value (IUV), Option Value (OV), Existence Value (EV) and Bequest Value (BV). The obtained result represent a contribution from economic science to the definition of environmental policies, allocation and distribution of financial resources, as well as the design and implementation of management plans or other strategic projection

Algunas consideraciones sobre la valoración económica de bienes y servicios ambientales en áreas protegidas.

La valoración económica ambiental de los recursos naturales, es sin dudas un importante mecanismo que tributa a favor de lograr una mejor conservación y gestión de los recursos naturales. En el caso de las áreas protegidas, el empleo de la modelación multicriterio como herramienta para la valoración económica de Bienes y Servicios Ambientales, constituye un aherramienta útil, que posibilita la integración de diversos componentes de carácter natural, económico y social, de manera que se favorezca la optimización de las decisiones a tomar, no en base a un único objetivo, sino en la búsqueda de un equilibrio sistémico, entre un conjunto de ellos. El objetivo del presente trabajo, se dirige a ilustrar la contribución de la valoración económica de bienes y servicios ambientales en áreas protegidas de la República de Cuba

Economic Science and Environment: A Contribution From the Environmental Economic Valuation

La valoración económica de bienes y servicios ambientales representa una importante contribución de la ciencia económica en la incorporación de la cuestiones ambientales en su marco analítico, cuya conceptualización acerca del valor económico fundamenta la viabilidad de la percepción económica asociada al proceso de toma de decisiones en espacios naturales. El objetivo del presente trabajo es fundamentar el papel de la valoración económica de bienes y servicios ambientales ante la situación ambiental global contemporánea, así como su aporte al proceso de toma de decisiones, a partir de los criterios ofrecidos por los autores. Para ello, se presentan algunas consideraciones sobre la relación de la ciencia económica y el medio ambiente, la necesidad de los procesos de valoración económica ambiental, su definición de valor económico, y por último se resumen algunos de los métodos de valoración económica que incorporan las funciones ambientales al análisis económico, lo que representa un aporte teórico metodológico ante la inexistencia de mercados reales para la valoración económica de los bienes y servicios ambientales

Relationship between the endothelial dysfunction and the expression of the β1-subunit of BK channels in a non-hypertensive sleep apnea group

Study objectives Vascular damage must be diagnosed early in patients with hypertension. In this regard, endothelial dysfunction (ED) is an early sign of vascular disease and a predictor of cardiovascular diseases. In obstructive sleep apnea (OSA), intermittent hypoxia triggers ED, but mechanisms are not clear. In this context, it has been described that BK channels regulates arterial tone and that chronic and intermittent hypoxia downregulates the expression of the BK channel β1-subunit facilitating vasoconstriction. Thus, we investigated the relationship among hypoxemia, ED, and mRNA expression of the β1-subunit in patients with severe OSA. We aimed to assess (1) ED in non-hypertensive patients with OSA using laser-Doppler flowmetry, (2) BK β1-subunit mRNA expression, and (3) the impact of continuous positive airway pressure (CPAP) treatment on ED and β1-subunit regulation. Methods OSA patients underwent 24-hour blood pressure monitoring to exclude hypertension. Laser-Doppler flowmetry was performed to assess ED, and β1-subunit mRNA expression was evaluated using a blood test of peripheral blood leukocytes at baseline and after 3 months of CPAP treatment. Results In normotensive patients with OSA, endothelial function correlated with the severity of OSA. CPAP improved endothelial function in normotensive OSA patients and the speed of the arterial response was significantly correlated with β1-subunit mRNA expression. β1-subunit mRNA expression at baseline correlated inversely with its change after CPAP. Conclusions Sleep apnea is related to ED in normotensive patients with OSA. CPAP therapy improves endothelial function and regulates β1-subunit mRNA expression

Sustainability Ranking for Cuban Tourist Destinations Based on Composite Indexes

Tourism sustainability evaluation has become an important issue in the development of this economic industry due to its dependence on natural environment quality and social acceptance. The study shows different ways to measure sustainability by means of composite indicators obtained from an initial set of quantitative and qualitative information. The use of different aggregation methods makes it possible to create rankings and offers remarkable contributions to the decision making process. We use the combination of dissimilar algorithms such as DP2 distance, Data Envelopment Analysis, Principal Component Analysis and Goal Programming to achieve these rankings and Borda Count to merge them into a single order to compare these destinations. Results shows different ways to measure sustainability using the overall information contained in a set of initial indicators and represent an important contribution to composite indicator’s building and for the formulation of new strategic actions, politics or other territorial or national projections

Obstructive Sleep Apnoea Syndrome, Endothelial Function and Markers of Endothelialization. Changes after CPAP

Study objectives This study tries to assess the endothelial function in vivo using flow-mediated dilatation (FMD) and several biomarkers of endothelium formation/restoration and damage in patients with obstructive sleep apnoea (OSA) syndrome at baseline and after three months with CPAP therapy. Design Observational study, before and after CPAP therapy. Setting and Patients We studied 30 patients with apnoea/hypopnoea index (AHI) >15/h that were compared with themselves after three months of CPAP therapy. FMD was assessed non-invasively in vivo using the Laser-Doppler flowmetry. Circulating cell-free DNA (cf-DNA) and microparticles (MPs) were measured as markers of endothelial damage and the vascular endothelial growth factor (VEGF) was determined as a marker of endothelial restoration process. Measurements and results After three month with CPAP, FMD significantly increased (1072.26 ± 483.21 vs. 1604.38 ± 915.69 PU, p< 0.005) cf-DNA and MPs significantly decreased (187.93 ± 115.81vs. 121.28 ± 78.98 pg/ml, p<0.01, and 69.60 ± 62.60 vs. 39.82 ± 22.14 U/μL, p<0.05, respectively) and VEGF levels increased (585.02 ± 246.06 vs. 641.11 ± 212.69 pg/ml, p<0.05). These changes were higher in patients with more severe disease. There was a relationship between markers of damage (r = -0.53, p<0.005) but not between markers of damage and restoration, thus suggesting that both types of markers should be measured together. Conclusions CPAP therapy improves FMD. This improvement may be related to an increase of endothelial restoration process and a decrease of endothelial damage