Control strategy to share reactive power and regulate voltage in microgrids with autonomous mode operation

The objective of this thesis is to develop control strategies for distributed generation (DG) systems, that allows to achieve reactive power sharing and regulate voltage in microgrids operated autonomously. The proposed control strategies present different alternatives to improve reactive power sharing among DGs that conform the microgrid and to regulate the voltage in the nodes. Thus, it is possible to contribute to the overcoming problems caused by the continuous connection and disconnection of power loads, avoiding DG tripping under this situation. The scope of the proposed strategies covers a wide range of possibilities, from regulating voltage in the nodes of the microgrid based on electric vehicle connection and disconnection, to urban and rural residential loads. The usefulness of these control strategies is focused on DG systems that operate in isolated mode with great integration of renewables, mainly located in remote areas. Therefore, in this research we worked on the comparison of both the consumption of rural and urban communities to obtain different load variations to test the control strategy in the microgrid. The control strategies included in this research are: virtual RMS voltage, variable virtual impedance, virtual current, and virtual voltage.El objetivo de esta tesis es desarrollar una estrategias de control para los sistemas de generación distribuida (DG), que permitan lograr compartir la potencia reactiva y regular el voltaje en las microrredes operadas de manera autónoma. Las estrategias de control propuestas presentan diferentes alternativas para mejorar la compartición de potencia reactiva entre las diferente DG que conforman la microrred y para regular el voltaje en los nodos. Por lo tanto, es posible contribuir a la superación de los problemas causados por la conexión y desconexión continua de las cargas, evitando el disparo de DG en esta situación. El alcance de las estrategias propuestas cubre una amplia gama de posibilidades, desde la regulación del voltaje en los nodos de la microrred basada en la conexión y desconexión del vehículo eléctrico, hasta las cargas residenciales urbanas y rurales. La utilidad de estas estrategias de control se centra en los sistemas de DG que funcionan en modo autónomo con una gran integración de energías renovables, principalmente ubicadas en áreas remotas. Por lo tanto, en esta investigación trabajamos en la comparación del consumo de las comunidades rurales y urbanas para obtener diferentes variaciones de cargas para probar la estrategia de control en la microrred. Las estrategias de control incluidas en esta investigación son: voltaje RMS virtual, impedancia virtual variable, corriente virtual y voltaje virtual.ColcienciasThesis presented as a partial requirement to obtain the title of: Doctor en Ingeniería - Línea de Investigación en Automática.Doctorad

FAIR national election studies: How well are we doing?

Election studies are an important data pillar in political and social science, as most political research investigations involve secondary use of existing datasets. Researchers depend on high-quality data because data quality determines the accuracy of the conclusions drawn from statistical analyses. We outline data reuse quality criteria pertaining to data accessibility, metadata provision, and data documentation using the FAIR Principles of research data management as a framework (Findability, Accessibility, Interoperability, and Reusability). We then investigate the extent to which a selection of election studies fulfils these criteria using studies from Western democracies. Our results reveal that although most election studies are easily accessible and well documented and that the overall level of data processing is satisfactory, some important deficits remain. Further analyses of technical documentation indicate that while a majority of election studies provide the necessary documents, there is still room for improvement

EEinfluss des RNAi Knockdowns von ausgewählten Genen des Folsäuremetabolismus auf Reproduktion, Lebensspanne und Genexpression von Caenorhabditis elegans

Folsäure ist ein essentielles wasserlösliches B-Vitamin und führt bei Mangel nachweislich zu gravierenden Erkrankungen beim Menschen. Innerhalb dieser Arbeit wird an Hand des Modellorganismus C. elegans der Metabolismus von Folsäure untersucht. Hierfür wird jeweils die Expression eines von fünf Genen (folt-1, Y4C6B.5, dhfr-1, mthf-1 und metr-1) des Folsäurestoffwechsels mittels RNAi verringert und die Auswirkungen auf die Genexpression der vier übrigen Gene, die Lebensspanne und die Reproduktion untersucht. Zunächst wird die mRNA Expression der RNAi behandelten Würmer mittels realtime RT-PCR gemessen, um die Funktionsfähigkeit des RNAi-Mechanismus sicherzustellen. Das Verfüttern von folt-1, dhfr-1 und metr-1 RNAi Bakterien führt grundsätzlich zu einer Verringerung der mRNA, allerdings ist der Effekt bei Y4C6B.5 und mthf-1 nicht zu sehen. Ein Mangel an FOLT-1 führt vermutlich zu einer geringeren Folataufnahme und daher zu einer reduzierten Expression der nachfolgenden Enzyme DHFR-1 und MTHF-1. Ebenso kann gezeigt werden, dass der Mangel des Transporters einen negativen Einfluss auf die Reproduktion und Lebensspanne von C. elegans hat. Sobald ein RNAi Knockdown der Dihydrofolatreduktase vorliegt, führt das wiederum zu einer Erhöhung der Expression des Folattransporters FOLT-1, vermutlich um die Menge an intrazelllulären Folaten, die nicht über die DHFR verstoffwechselt werden müssen, zu erhöhen. Der Mangel an DHFR-1 führt in beiden Wurmstämmen zu einer reduzierten Lebensspanne, hat aber keinen Einfluss auf die Nachkommenschaft. Ein RNAi Knockdown der Methioninsynthase, welche verantwortlich für Tetrahydrofolat aus 5-Methylentetrahydrofolat und die Remethylierung von Homocystein zu Methionin ist, bedingt bei RNAi sensitiven Würmern eine Verringerung der Reproduktionsrate und auch eine verkürzte Lebensspanne. Wie bereits in anderen Organismen gezeigt, kann auch hier bestätigt werden, dass ein Eingriff in den Folsäurestoffwechsel, sowohl im Bereich der Folataufnahme wie auch im Bereich von Schlüsselenzymen, zum einen durch die veränderte Expression von Genen kompensiert werden kann und zum anderen aber auch einen negativen Einfluss auf die Reproduktion und Lebensspanne von C. elegans hat.Folic acid is an essential water-soluble B vitamin and deficiency has been shown in more serious medical conditions in humans. Within this work on hand of the model organism C. elegans, the metabolism of folic acid is studied. Therefore respectively were the expression one of the five genes (folt-1, Y4C6B.5, dhfr-1, mthf-1 and metr-1) of folic acid metabolism, reduced by means of the RNAi mechanism and the effect on the gene expression of the remaining four genes, the life span and the progeny examined. The mRNA expression of the RNAi treated worms is measured by real time RT-PCR to ensure the functionality of the RNAi mechanism. The feeding of folt-1, dhfr-1 and metr-1 RNAi bacteria generally leads to a reduction in the mRNA, but not in Y4C6B.5 and mthf-1. A deficiency of FOLT-1 presumably leads to a reduced folate intake and hence to a reduced expression of the following enzymes DHFR-1 and MTHF-1. Also it can be shown that the lack of the transporter has a negative effect on reproduction and life span of C. elegans. When a present RNAi knockdown of dihydrofolate reductase, which in turn leads to an increase in the expression of the folate transporter FOLT-1, probably in order to increase the amount intracellular folate, which need not be metabolized via the DHFR. The lack of DHFR-1 reduced life span but has no effect on the offspring into the two worm strains. An RNAi knockdown of methionine synthase, which is responsible for 5-methylenetetrahydrofolate from tetrahydrofolate and the remethylation of homocysteine to methionine, due in RNAi sensitive worms reducing the reproduction rate and a shortened life span. As already shown in other organisms, which can also be confirmed that an intervention in the folic acid metabolism, both in the field of folate as well as in the range of key enzymes, on the one hand can be compensated by the altered expression of genes and to the other also has a negative influence on the reproduction and life span of C. elegans

Análisis de la responsabilidad social empresarial en la viabilidad social de los proyectos mineros en la región Piura, 2020

La presente investigación titulada: Análisis de la Responsabilidad Social Empresarial en la Viabilidad Social de los Proyectos Mineros en la Región Piura, 2020, tiene como objetivo analizar cómo la responsabilidad social empresarial posibilita la viabilidad social de los proyectos mineros de la región Piura, 2020. La investigación es de diseño no experimental, transversal, descriptivo; la recolección de datos se hizo a través de una técnica que es la encuesta . Para recoger los datos se aplicó un cuestionario a una muestra de 123 pobladores de edad entre dieciocho a sesenta y cinco años de las zonas rurales de las provincias de Ayabaca y Huancabamba donde existen concesiones mineras. Los datos de las encuestas aplicadas fueron procesados por el programa SPSS versión 26 y Microsoft Excel, obteniendo como resultado que la población percibe que la conflictividad social obedece a que las relaciones de las empresas con la comunidad no son positivas, no se propicia el dialogo, no se establecen mesas de diálogo; la licencia social para operar debe ser otorgada por las comunidades de las zonas involucradas

Usefulness of component resolved analysis of cat allergy in routine clinical practice

Background: Cat allergy is of great importance, and its prevalence is increasing worldwide. Cat allergens and house dust mite allergens represent the major indoor allergens;however, they are ubiquitous. Cat sensitization and allergy are known risk factors for rhinitis, bronchial hyperreactivity and asthma. Thus, the diagnosis of sensitization to cats is important for any allergist. Methods: 70 patients with positive skin prick tests for cats were retrospectively compared regarding their skin prick test results, as well as their specific immunoglobulin E antibody profiles with regard to their responses to the native cat extract, rFel d 1, nFel d 2 and rFel d 4. 35 patients were allergic to cats, as determined by positive anamnesis and/or nasal provocation with cat allergens, and 35 patients exhibited clinically non-relevant sensitization, as indicated by negative anamnesis and/or a negative nasal allergen challenge. Results: Native cat extract serology testing detected 100% of patients who were allergic to cats but missed eight patients who showed sensitization in the skin prick test and did not have allergic symptoms. The median values of the skin prick test, as well as those of the specific immunoglobulin E antibodies against the native cat extract, were significantly higher for allergic patients than for patients with clinically non-relevant sensitization. Component based diagnostic testing to rFel d 1 was not as reliable. Sensitization to nFel d 2 and rFel d 4 was seen only in individual patients. Conclusion: Extract based diagnostic methods for identifying cat allergy and sensitization, such as the skin prick test and native cat extract serology, remain crucial in routine clinical practice. In our study, component based diagnostic testing could not replace these methods with regard to the detection of sensitization to cats and differentiation between allergy and sensitization without clinical relevance. However, component resolved allergy diagnostic tools have individual implications, and future studies may facilitate a better understanding of its use and subsequently may improve the clinical management of allergic patients

Sub-Micrometer-Scale Mapping of Magnetite Crystals and Sulfur Globules in Magnetotactic Bacteria Using Confocal Raman Micro-Spectrometry

The ferrimagnetic mineral magnetite Fe3O4 is biomineralized by magnetotactic microorganisms and a diverse range of animals. Here we demonstrate that confocal Raman microscopy can be used to visualize chains of magnetite crystals in magnetotactic bacteria, even though magnetite is a poor Raman scatterer and in bacteria occurs in typical grain sizes of only 35-120 nm, well below the diffraction-limited optical resolution. When using long integration times together with low laser power (<0.25 mW) to prevent laser induced damage of magnetite, we can identify and map magnetite by its characteristic Raman spectrum (303, 535, 665 cm(-1)) against a large autofluorescence background in our natural magnetotactic bacteria samples. While greigite (cubic Fe3S4; Raman lines of 253 and 351 cm(-1)) is often found in the Deltaproteobacteria class, it is not present in our samples. In intracellular sulfur globules of Candidatus Magnetobacterium bavaricum (Nitrospirae), we identified the sole presence of cyclo-octasulfur (S-8: 151, 219, 467 cm(-1)), using green (532 nm), red (638 nm) and near-infrared excitation (785 nm). The Raman-spectra of phosphorous-rich intracellular accumulations point to orthophosphate in magnetic vibrios and to polyphosphate in magnetic cocci. Under green excitation, the cell envelopes are dominated by the resonant Raman lines of the heme cofactor of the b or c-type cytochrome, which can be used as a strong marker for label-free live-cell imaging of bacterial cytoplasmic membranes, as well as an indicator for the redox state