Search

This paper presents a fault detection system for photovoltaic standalone applications based on Gaussian Process Regression (GPR). The installation is a communication repeater from the Confederación Hidrográfica del Ebro (CHE), public institution which manages the hydrographic system of Aragón, Spain. Therefore, fault-tolerance is a mandatory requirement, complex to fulfill since it depends on the meteorology, the state of the batteries and the power demand. To solve it, we propose an online voltage prediction solution where GPR is applied in a real and large dataset of two years to predict the behavior of the installation up to 48 hour. The dataset captures electrical and thermal measures of the lead-acid batteries which sustain the installation. In particular, the crucial aspect to avoid failures is to determine the voltage at the end of the night, so different GPR methods are studied. Firstly, the photovoltaic standalone installation is described, along with the dataset. Then, there is an overview of GPR, emphasizing in the key aspects to deal with real and large datasets. Besides, three online recursive multistep GPR model alternatives are tailored, justifying the selection of the hyperparameters: Regular GPR, Sparse GPR and Multiple Experts (ME) GPR. An exhaustive assessment is performed, validating the results with those obtained by Long Short-Term Memory (LSTM) and Nonlinear Autoregressive Exogenous Model (NARX) networks. A maximum error of 127 mV and 308 mV at the end of the night with Sparse and ME, respectively, corroborates GPR as a promising tool. [ABSTRACT FROM AUTHOR]

Corbicula fluminea is an aggressive invasive species that has successfully colonized aquatic habitats worldwide, producing changes in natural environments and impacting endemic populations. As disturbed environments may favor the adaptive success of exotic species over native ones, we studied the fitness response of two freshwater bivalves, invasive C. fluminea and native Diplodon delodontus, to the presence of metals in the Parana de la Palmas River. To assess the health status of both species, we analyzed morphological and histological alterations in the digestive gland and their relation to metal concentrations in this organ and in the water. Water and specimens sampling took place in the first section of the delta of the Parana River in June and September. Most metal concentrations increased in the river, although in the digestive gland only iron in D. delodontus and nickel and zinc in C. fluminea increased seasonally. Digestive gland factor and hepatosomatic index indicated higher values in C. fluminea in both periods. Despite histological analysis showing a decrease in atrophic tubules frequency in both species, which was followed by histomorphometric parameters of the epithelium and lumen of the digestive tubules, C. fluminea exhibited a greater physiological capacity for metal metabolism and recovery. These results suggest that the physiological characteristics of the Asian clam C. fluminea, combined with its reproductive efficiency and broad dispersal capacities, could explain its invasive dispersal competence over the D. delodontus in the disturbed environmental conditions observed in the Parana de las Palmas River. [ABSTRACT FROM AUTHOR]

Axial spondyloarthritis (axSpA) comprises a spectrum of chronic inflammatory manifestations affecting the axial skeleton and represents a challenge for diagnosis and treatment. Our objective was to generate a set of evidence-based recommendations for the management of axSpA for physicians, health professionals, rheumatologists and policy decision makers in Pan American League of Associations for Rheumatology (PANLAR) countries. Grading of Recommendations, Assessment, Development and Evaluation-ADOLOPMENT methodology was used to adapt existing recommendations after performing an independent systematic search and synthesis of the literature to update the evidence. A working group consisting of rheumatologists, epidemiologists and patient representatives from countries within the Americas prioritized 13 topics relevant to the context of these countries for the management of axSpA. This Evidence-Based Guideline article reports 13 recommendations addressing therapeutic targets, the use of NSAIDs and glucocorticoids, treatment with DMARDs (including conventional synthetic, biologic and targeted synthetic DMARDs), therapeutic failure, optimization of the use of biologic DMARDs, the use of drugs for extra-musculoskeletal manifestations of axSpA, non-pharmacological interventions and the follow-up of patients with axSpA. This Evidence-Based Guideline presents the first Pan American League of Associations for Rheumatology recommendations for the management of axial spondyloarthritis, addressing therapeutic targets, the use of pharmacological and non-pharmacological interventions and monitoring of patients. [ABSTRACT FROM AUTHOR]