332 research outputs found

    Grid-connected photovoltaic systems based on nonlinear control.

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    Nowadays, due to the high-scale penetration of photovoltaic systems, reliable and efficient grid-connected photovoltaic (PV) systems utilizing the advances of power electronics and control system technology are desirable. Thus, single-stage grid-connected photovoltaic systems, have gained attention, especially in low voltage applications. However, PV systems exhibit nonlinear behavior that could negatively affect the performance of the system if they are not adequately compensated for. In this dissertation, using the general structure for the synchronous dq0 frame, a single-stage three-phase grid-connected photovoltaic system, and a single-stage single-phase grid-connected PV system, both with a nonlinear control strategy, are developed to track the maximum power and to control the active and reactive power, without the necessity of an additional power converter. A novel trajectory of the reference current is obtained online taking into account the dynamics of the DC link capacitor and the switching function of the inverter. Unlike to the three-phase system, the single-phase system includes a novel method to mitigate the double line-frequency current ripple of the PV array, which is the major drawback of the single-phase PV inverter. Moreover, based on the preceded work, the nonlinear controller is combined with adaptive control to estimate the unknown disturbances that physically could appear in the circuit and affect the performance of the system. The stability of the systems and boundedness of signals are demonstrated by Lyapunov stability analysis. Simulation results show the effectiveness and robustness of the proposed controllers to track the maximum power and to control the active and reactive power

    Selective pressure along a latitudinal gradient affects subindividual variation in plants

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    Individual plants produce repeated structures such as leaves, flowers or fruits, which, although belonging to the same genotype, are not phenotypically identical. Such subindividual variation reflects the potential of individual genotypes to vary with micro-environmental conditions. Furthermore, variation in organ traits imposes costs to foraging animals such as time, energy and increased predation risk. Therefore, animals that interact with plants may respond to this variation and affect plant fitness. Thus, phenotypic variation within an individual plant could be, in part, an adaptive trait. Here we investigated this idea and we found that subindividual variation of fruit size of Crataegus monogyna, in different populations throughout the latitudinal gradient in Europe, was explained at some extent by the selective pressures exerted by seed-dispersing birds. These findings support the hypothesis that within-individual variation in plants is an adaptive trait selected by interacting animals which may have important implications for plant evolution.This work was supported by the Spanish Ministry of Science and Education (project CGL2005-03826) and the European Commission (FEDER program). M.S. was the recipient of a María Barbeito fellowship (Galicia regional government, Spain) and a Fundación Pedro Barrié de la Maza grant. A.R.L. received financial support from the Spanish Research Council (JAEDoc program, partially funded by the European Social Fund) during the preparation of the manuscriptS

    Ceratobasidium sp. AG-A, root pathogen of Calibrachoa hybrida

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    Calibrachoa (Calibrachoa hybrida, Solanaceae) is an annual flowering ornamental plant, which is widely used in landscape design. In October 2019, 5% of the plants grown in a greenhouse in Buenos Aires, Argentina, showed a sudden wilt characterized by chlorosis, loss of turgor, and root rot. The objective of this study was to identify the causal agent of the disease. Five morphologically identical isolates developed from the roots of wilting plants. One of the isolates was selected and identified using morphological and molecular markers, while its pathogenicity was confirmed by Koch’s postulates. The obtained results allow concluding that Ceratobasidium sp. AG-A (anamorph Rhizoctonia sp.) is the causal agent of the disease. To the best of the authors’ knowledge, this is the first report of Ceratobasidium sp. as pathogen of calibrachoa in the world.Fil: Borrelli, N.P. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Floricultura; Argentina. Universidad de Buenos Aires. Facultad de Agronomía, ArgentinaFil: Moreno, María Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Cientifico Tecnolológico Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología. Laboratorio de Biología Funcional y Biotecnología; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Agronomía. Area Microbiología; ArgentinaFil: Stenglein, Sebastian Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Cientifico Tecnolológico Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología. Laboratorio de Biologia Funcional y Biotecnología; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Stancanelli, Santiago. Instituto Nacional de Tecnología Agropecuaria (INTA). Instuto de Floricultura; ArgentinaFil: Wright, Eduardo Roberto. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Fitopatología; ArgentinaFil: Rivera, Marta Carolina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Floricultura; Argentin

    Directional deep brain stimulation for Parkinson's disease: results of an international crossover study with randomized, double-blind primary endpoint

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    Objective: Published reports on directional deep brain stimulation (DBS) have been limited to small, single-center investigations. Therapeutic window (TW) is used to describe the range of stimulation amplitudes achieving symptom relief without side effects. This crossover study performed a randomized double-blind assessment of TW for directional and omnidirectional DBS in a large cohort of patients implanted with a DBS system in the subthalamic nucleus for Parkinson’s disease. Materials and Methods: Participants received omnidirectional stimulation for the first three months after initial study pro gramming, followed by directional DBS for the following three months. The primary endpoint was a double-blind, randomized evaluation of TW for directional vs omnidirectional stimulation at three months after initial study programming. Additional data recorded at three- and six-month follow-ups included stimulation preference, therapeutic current strength, Unified Parkinson’s Disease Rating Scale (UPDRS) part III motor score, and quality of life. Results: The study enrolled 234 subjects (62 ± 8 years, 33% female). TW was wider using directional stimulation in 183 of 202 subjects (90.6%). The mean increase in TW with directional stimulation was 41% (2.98 ± 1.38 mA, compared to 2.11 ± 1.33 mA for omnidirectional). UPDRS part III motor score on medication improved 42.4% at three months (after three months of omnidi rectional stimulation) and 43.3% at six months (after three months of directional stimulation) with stimulation on, compared to stimulation off. After six months, 52.8% of subjects blinded to stimulation type (102/193) preferred the period with directional stimulation, and 25.9% (50/193) preferred the omnidirectional period. The directional period was preferred by 58.5% of clinicians (113/193) vs 21.2% (41/193) who preferred the omnidirectional period. Conclusion: Directional stimulation yielded a wider TW compared to omnidirectional stimulation and was preferred by blinded subjects and clinicians

    Evolution of a long-lived volcanic complex: the Chachani case study (south Peru)

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    The study of numerous individual volcanoes carried out in the Central Andean Volcanic Zone over the past 20 years has provided information to better understand active volcanism in the Peruvian Andes. However, large-sized, dormant volcanic complexes remain much less understood due to their complexity or because the impact of individual active volcanoes on populated areas has led researchers to prioritize their study on the most recent composite cones. Large, long-lived volcanic complexes have not yet been considered in volcanological studies in Peru, although they belie a rich history of eruptive activity that may be more recent than previously thought. The Chachani Volcanic Complex (CVC) is one of the few Andean volcanic complexes in which the relationships between stratigraphy, chronology and compositional changes are considered to understand the compositional evolution of a long-lived magmatic system

    Quantitative nanoscale electrostatics of viruses

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    Electrostatics is one of the fundamental driving forces of the interaction between biomolecules in solution. In particular, the recognition events between viruses and host cells are dominated by both specific and non-specific interactions and the electric charge of viral particles determines the electrostatic force component of the latter. Here we probe the charge of individual viruses in liquid milieu by measuring the electrostatic force between a viral particle and the Atomic Force Microscope tip. The force spectroscopy data of co-adsorbed 29 bacteriophage proheads and mature virions, adenovirus and minute virus of mice capsids is utilized for obtaining the corresponding density of charge for each virus. The systematic differences of the density of charge between the viral particles are consistent with the theoretical predictions obtained from X-ray structural data. Our results show that the density of charge is a distinguishing characteristic of each virus, depending crucially on the nature of the viral capsid and the presence/absence of the genetic material.MINECO of Spain through project FIS2011-29493, FIS2014-59562-R, and the Spanish Interdisciplinary Network on the Biophysics of Viruses (Biofivinet, FIS2011-16090-E). CSM acknowledges funding from BFU2013- 41249-P, and Biofivinet. MGM acknowledges funding from the Spanish Government (BIO2012-37649), Comunidad de Madrid (S-505/MAT-0303), and by an institutional grant from Fundación Areces to the Centro de Biología MolecularPeer Reviewe

    Mapping Height and Biomass of Mangrove Forests in Everglades National Park with SRTM Elevation Data

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    We produced a landscape scale map of mean tree height in mangrove forests in Everglades National Park (ENP) using the elevation data from the Shuttle Radar Topography Mission (SRTM). The SRTM data was calibrated using airborne lidar data and a high resolution USGS digital elevation model (DEM). The resulting mangrove height map has a mean tree height error of 2.0 m (RMSE) over a pixel of 30 m. In addition, we used field data to derive a relationship between mean forest stand height and biomass in order to map the spatial distribution of standing biomass of mangroves for the entire National Park. The estimation showed that most of the mangrove standing biomass in the ENP resides in intermediate- height mangrove stands around 8 m. We estimated the total mangrove standing biomass in ENP to be 5.6 X 109 kg

    Selection and chemical composition of plant species consumed by goats under drought conditions in three microregions of the Comarca Lagunera, Mexico

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    Objective: To evaluate the plant selection of the diet of goats during the dry season and the chemical composition of the said plants in three microregions of the Comarca Lagunera, Mexico. Design/Methodology/Approach: Three microregions were identified within the Comarca Lagunera: 1) mountain slope, 2) plain, and 3) cultivation areas. The selection of the goat diet, the availability of forage, and the nutritional composition (CP, EE, DNF, AFD, NFC, TDN, and NEl) of plant species and strata were evaluated in the three microregions. Results: The shrubs and herbaceous in the Comarca Lagunera had the highest forage availability and a better nutritional profile during winter. On the one hand, these plant strata had an adequate protein content. On the other hand, the overall energy content reached <1 Mcal kg-1 DM. Study Limitations/Implications: The plant strata have an adequate protein content; however, the energy content is not enough and limits growth. Consequently, supplementation programs for grazing dairy goats in the Comarca Lagunera must include sources of energy. Findings/Conclusions: Regardless of the microregion, the energy content of the species consumed by grazing dairy goats in the Comarca Lagunera is low

    Management of Parkinson's disease and other movement disorders in women of childbearing age: Part 2

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    Introducción Muchas enfermedades que cursan con trastornos del movimiento hipercinético comienzan o afectan a mujeres en edad fértil. Es importante conocer los riesgos que tienen las mujeres con estas enfermedades durante el embarazo, así como los posibles efectos de los tratamientos sobre el feto. Objetivos Definir las características clínicas y los factores que condicionan la vida de la mujer en edad fértil con distonía, corea, síndrome de Tourette, temblor y síndrome de piernas inquietas. Definir una guía de actuación y manejo del embarazo y lactancia en las pacientes con esta enfermedad. Desarrollo Este documento de consenso se ha realizado mediante una búsqueda bibliográfica exhaustiva y discusión de los contenidos llevadas a cabo por un Grupo de Expertos en Trastornos del Movimiento de la Sociedad Española de Neurología (SEN). Conclusiones En todas las mujeres que padecen o comienzan con trastornos del movimiento hipercinéticos se debe valorar el riesgo-beneficio de los tratamientos, reducir al máximo la dosis eficaz o administrarlo de forma puntual en los casos en que sea posible. En aquellas enfermedades de causa hereditaria es importante un consejo genético para las familias. Es importante reconocer los trastornos del movimiento desencadenados durante el embarazo como determinadas coreas y síndrome de piernas inquietas.Introduction Many diseases associated with hyperkinetic movement disorders manifest in women of childbearing age. It is important to understand the risks of these diseases during pregnancy, and the potential risks of treatment for the fetus. Objectives This study aims to define the clinical characteristics and the factors affecting the lives of women of childbearing age with dystonia, chorea, Tourette syndrome, tremor, and restless legs syndrome, and to establish guidelines for management of pregnancy and breastfeeding in these patients. Results This consensus document was developed through an exhaustive literature search and a discussion of the content by a group of movement disorder experts from the Spanish Society of Neurology. Conclusions We must evaluate the risks and benefits of treatment in all women with hyperkinetic movement disorders, whether pre-existing or with onset during pregnancy, and aim to reduce effective doses as much as possible or to administer drugs only when necessary. In hereditary diseases, families should be offered genetic counselling. It is important to recognise movement disorders triggered during pregnancy, such as certain types of chorea and restless legs syndrome

    Effectiveness and safety of guselkumab for the treatment of psoriasis in real-world settings at 24 weeks : A retrospective, observational, multicentre study by the Spanish Psoriasis Group

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    Altres ajuts: Acord transformatiu CRUE-CSICData on the effectiveness and safety of a drug in real-world clinical practice complement the evidence from clinical trials, which are carried out in a different setting. Little has been published on the effectiveness and safety of guselkumab in the treatment of psoriasis in clinical practice. The ojective of this study was to assess the effectiveness and safety of guselkumab at 24 weeks in patients with moderate to severe plaque psoriasis in routine clinical practice. A retrospective, multicentre study of adult patients with moderate to severe plaque psoriasis treated with guselkumab for at least 24 weeks was carried out in Spain. We studied 343 patients, 249 of whom were followed for 24 weeks. By week 24, the mean (SD) psoriasis area severity index (PASI) had decreased from 11.1 (7.3) to 1.7 (2.8) (−9.3; [−10.2;-8.4]), 85.9% of the patients had achieved PASI score of 4 or less and 77.9% a PASI score of 2 or less. In terms of relative PASI response, 59.4% of the patients achieved a PASI-90 response and 49.0% a PASI-100 response. On multivariate analysis, two factors reduced the probability of a PASI of 2 or less at 24 weeks: a BMI ≥30 (OR, 0.44; 95% CI, 0.22-0.88) and a greater previous exposure to biologic therapy (OR, 0.69; 95% CI, [0.56-0.84]). Adverse events were rare (9.9%) and led to withdrawal from treatment in only nine patients (2.6%) by the end of the follow-up period. The results of this study confirm the high efficacy and safety of guselkumab indicated by the clinical trial data. In clinical practice, the absolute PASI score appears to be a better marker of response to treatment than the relative value
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