Frequency regulation in electric power systems using deferrable loads

Incluye bibliografía y anexosCon el advenimiento del paradigma de la red inteligente (Smart Grid) y las energías renovables, se hace necesario estudiar el almacenamiento de energía generada que no se consume al momento. En esta tesis, se indaga en el papel de un “load agregator” que administra un conjunto de cargas eléctricas y aprovecha la flexibilidad de las mismas para regular la frecuencia de una red. Se estudia el problema desde un punto de vista macroscópico, sin entrar en detalles de cargas individuales. Se propone un set de modelos ODE para predecir la evolución de la potencia consumida por el cluster de cargas y se diseñan controladores para estos modelos, con el fin de poder seguir las referencias de potencia externa. Finalmente, se sugieren algunos algoritmos posibles para implementar el control a cargas individuales. Las simulaciones muestran que este sistema podría proporcionar valiosos servicios a las redes eléctricas, si existiese suficiente infraestructura de comunicaciones.ANII - POS_NAC_2013_1_11675

Algoritmos de aprendizaje automático con aplicación a enjambres de robots

Los sistemas robóticos de enjambre o de múltiples agentes constituyen un área de investigación en creciente desarrollo. Para proveer infraestructura inalámbrica a demanda es necesario desplegar un equipo secundario de robots que garanticen la conectividad del enjambre. En este trabajo explicamos un algoritmo de posicionamiento óptimo para este equipo de robots, consistente en una etapa de optimización convexa sobre un modelo de canal probabilístico y una siguiente etapa de maximización de la conectividad de un grafo Laplaciano. Para mostrar la ventaja de esta formulación matemática, llevamos a cabo tanto simulaciones como experimentos que fueron realizados con una flota de 10 Vehículos Aéreos no Tripulados (UAV por sus siglas en inglés) -ensamblados y configurados por nuestro grupo de investigación- basados en el modelo DJI Flame-Wheel y equipados con mini-computadoras Intel NUC a bordo y conectividad Wi-Fi. Para los experimentos realizados, los UAVs establecieron una red ad-hoc a través de nodos ROS multi-master en sistema operativo Ubuntu 18. Existe a su vez otra familia de algoritmos autónomos de creciente interés conocida como aprendizaje por recompensas o Reinforcement Learning (RL), en los que el control a aplicar surge a partir de optimizar una señal de recompensa. En esta tesis estudiamos un problema de monitoreo, formulado a partir de restricciones de ocupación de regiones a monitorear por uno o múltiples agentes, que se lleva a un problema de RL en el que las variables duales actúan como señal de recompensa. Para resolver el problema en el caso de un único agente monitoreando varias regiones, diseñamos una parametrización por medio de una red neuronal que procesa en paralelo las variables primales y las duales. Con esta novedad estructural, la red aprende a elegir políticas de navegación en función del grado de satisfacción de las restricciones, que se observa en tiempo real a través de las variables duales. Para el caso de múltiples agentes, simulamos una versión simplificada del problema con un espacio de estados discreto y dos agentes, e imponiendo que los agentes tengan políticas distribuidas logramos un desempeño comparable al de una política centralizada.Swarm or multi-agent robotic systems are a growing area of research. To provide wireless infrastructure on demand, it is necessary to deploy a secondary team of robots that guarantee the connectivity of the swarm. In this paper we explain an optimal positioning algorithm for this team of robots, consisting of a convex optimization stage on a probabilistic channel model and a subsequent connectivity maximization stage of a Laplacian graph. To show the advantage of this mathematical formulation, we carried out both simulations and experiments that were carried out with a fleet of 10 Unmanned Aerial Vehicles (UAV) -assembled and con gured by our research group- based on the model DJI Flame-Wheel and equipped with onboard Intel NUC mini-computers and Wi-Fi connectivity. For the experiments carried out, the UAVs established an ad-hoc network through ROS multi-master nodes in the Ubuntu 18 operating system. There is also another family of autonomous algorithms of growing interest known as Reinforcement Learning (RL), in which the control to be applied arises from optimizing a reward signal. In this thesis we study a monitoring problem, formulated from the occupation restrictions of regions to be monitored by one or multiple agents, which leads to an RL problem in which the dual variables act as a reward signal. To solve the problem in the case of a single agent monitoring several regions, we designed a parameterization through a neural network that processes the primal and dual variables in parallel. With this structural novelty, the network learns to choose navigation policies based on the degree of satisfaction of the constraints, which is observed in real time through the dual variables. For the multi-agent case, we simulate a simpli ed version of the problem with a discrete state space and two agents, and by imposing that the agents have distributed policies, we achieve performance comparable to that of a centralized policy.Beca de Posgrado de la CAP, Udela

Bypassing Iron Storage in Endodermal Vacuoles Rescues the Iron Mobilization Defect in the Natural Resistance Associated-Macrophage Protein3natural Resistance Associated-Macrophage Protein4 Double Mutant

To improve seed iron (Fe) content and bioavailability, it is crucial to decipher the mechanisms that control Fe storage during seed development. In Arabidopsis (Arabidopsis thaliana) seeds, most Fe is concentrated in insoluble precipitates, with phytate in the vacuoles of cells surrounding the vasculature of the embryo. NATURAL RESISTANCE ASSOCIATED-MACROPHAGE PROTEIN3 (AtNRAMP3) and AtNRAMP4 function redundantly in Fe retrieval from vacuoles during germination. When germinated under Fe-deficient conditions, development of the nramp3nramp4 double mutant is arrested as a consequence of impaired Fe mobilization. To identify novel genes involved in seed Fe homeostasis, we screened an ethyl methanesulfonate-mutagenized population of nramp3nramp4 seedlings for mutations suppressing their phenotypes on low Fe. Here, we report that, among the suppressors, two independent mutations in the VACUOLAR IRON TRANSPORTER1 (AtVIT1) gene caused the suppressor phenotype. The AtVIT1 transporter is involved in Fe influx into vacuoles of endodermal and bundle sheath cells. This result establishes a functional link between Fe loading in vacuoles by AtVIT1 and its remobilization by AtNRAMP3 and AtNRAMP4. Moreover, analysis of subcellular Fe localization indicates that simultaneous disruption of AtVIT1, AtNRAMP3, and AtNRAMP4 limits Fe accumulation in vacuolar globoids

Mitofusins modulate the increase in mitochondrial length, bioenergetics and secretory phenotype in therapy-induced senescent melanoma cells

Cellular senescence is an endpoint of chemotherapy, and targeted therapies in melanoma and the senescence-associated secretory phenotype (SASP) can affect tumor growth and microenvironment, influencing treatment outcomes. Metabolic interventions can modulate the SASP, and an enhanced mitochondrial energy metabolism supports resistance to therapy in melanoma cells. Herein, we assessed the mitochondrial function of therapy-induced senescent melanoma cells obtained after exposing the cells to temozolomide (TMZ), a methylating chemotherapeutic agent. Senescence induction in melanoma was accompanied by a substantial increase in mitochondrial basal, ATP-linked, and maximum respiration rates and in coupling efficiency, spare respiratory capacity, and respiratory control ratio. Further examinations revealed an increase in mitochondrial mass and length. Alterations in mitochondrial function and morphology were confirmed in isolated senescent cells, obtained by cell-size sorting. An increase in mitofusin 1 and 2 (MFN1 and 2) expression and levels was observed in senescent cells, pointing to alterations in mitochondrial fusion. Silencing mitofusin expression with short hairpin RNA (shRNA) prevented the increase in mitochondrial length, oxygen consumption rate and secretion of interleukin 6 (IL-6), a component of the SASP, in melanoma senescent cells. Our results represent the first in-depth study of mitochondrial function in therapy-induced senescence in melanoma. They indicate that senescence increases mitochondrial mass, length and energy metabolism; and highlight mitochondria as potential pharmacological targets to modulate senescence and the SASP.Agencia Nacional de Investigación e Innovación FCE_1_2017_1_13602

The moss-specific transcription factor PpERF24 positively modulates immunity against fungal pathogens in Physcomitrium patens

APETALA2/ethylene response factors (AP2/ERFs) transcription factors (TFs) have greatly expanded in land plants compared to algae. In angiosperms, AP2/ERFs play important regulatory functions in plant defenses against pathogens and abiotic stress by controlling the expression of target genes. In the moss Physcomitrium patens, a high number of members of the ERF family are induced during pathogen infection, suggesting that they are important regulators in bryophyte immunity. In the current study, we analyzed a P. patens pathogen-inducible ERF family member designated as PpERF24. Orthologs of PpERF24 were only found in other mosses, while they were absent in the bryophytes Marchantia polymorpha and Anthoceros agrestis, the vascular plant Selaginella moellendorffii, and angiosperms. We show that PpERF24 belongs to a moss-specific clade with distinctive amino acids features in the AP2 domain that binds to the DNA. Interestingly, all P. patens members of the PpERF24 subclade are induced by fungal pathogens. The function of PpERF24 during plant immunity was assessed by an overexpression approach and transcriptomic analysis. Overexpressing lines showed increased defenses to infection by the fungal pathogens Botrytis cinerea and Colletotrichum gloeosporioides evidenced by reduced cellular damage and fungal biomass compared to wild-type plants. Transcriptomic and RT-qPCR analysis revealed that PpERF24 positively regulates the expression levels of defense genes involved in transcriptional regulation, phenylpropanoid and jasmonate pathways, oxidative burst and pathogenesis-related (PR) genes. These findings give novel insights into potential mechanism by which PpERF24 increases plant defenses against several pathogens by regulating important players in plant immunity

Methylation profiling RIN3 and MEF2C identifies epigenetic marks associated with sporadic early onset Alzheimer’s disease

A number of genetic loci associate with early onset Alzheimer’s disease (EOAD), however the drivers of this disease remains enigmatic. Genome wide association and in-vivo modelling have shown that loss-of-function e.g. ABCA7, reduced levels of SIRT1, MEFF2C or increases levels of PTK2β confer risk or link to the pathogenies. It is known that DNA methylation can profoundly affect gene expression and can impact on the composition of the proteome, therefore the aim of this study is to assess if genes associated with sporadic EOAD are differentially methylated. Epi-profiles of DNA extracted from blood and cortex were compared using a pyrosequencing platform. We identified significant group-wide hypomethylation in AD blood when compared to controls for 7 CpGs located within the 3’UTR of RIN3 (CpG1 P=0.019, CpG2 p=0.018, CpG3 p=0.012, CpG4 p=0.009, CpG5 p=0.002, CpG6 p=0.018 and CpG7 p=0.013 respectively; AD / Control n=22 / 26; Male / Female, 27 / 21). Observed effects were not gender specific. No group wide significant differences were found in the promoter methylation of PTK2β, ABCA7, SIRT1 or MEF2C, genes known to associate with LOAD. A rare and significant difference in methylation was observed for one CpG located upstream of the MEF2C promoter in one AD individual only (22% reduction in methylation, p=2.0E-10; Control n=26, AD n=25, Male / Female n=29 / 22). It is plausible aberrant methylation may mark sEOAD in blood and may manifest in some individuals as rare epi-variants for genes linked to sEOAD

Benzodiacepinas y fractura de cadera: estudio de casos y controles

Introduc ción: las ben zo dia ce pi nas (BZD) son me di ca men tos am plia men te usa dos en la prác ti ca clí ni ca. Son efi ca ces en el tra ta mien to sin to má ti co de an sie dad, in som nio a cor to pla zo, cri sis epi lép ti cas, sín dro me de abs ti nen cia al cohó li ca e in duc - ción anes té si ca. En an cia nos pue den te ner efec tos ad ver sos como in coor di na ción mo to ra y de bi li dad mus cu lar que lle van a caí das, au men tan do el ries go de frac tu ra de ca de ra. Obje ti vo: de ter mi nar si exis te aso cia ción en tre el con su mo de BZD y el ries go de frac tu ra de ca de ra. Ma te rial y mé to do: se di se ñó un es tu dio de ca sos y con tro les (1:2) du ran te seis me ses (tres me ses en 2013 y tres me ses en 2014). Se de fi nió “caso” a los pa cien tes con frac tu ra trau má ti ca de ca de ra. Se de fi nió “con trol” a pa cien tes de igual sexo y edad (± 5 años) que hu bie ran in gre sa do en la mis ma se ma na por una cau sa di fe ren te (mé di ca o qui rúr gi ca). Se re le va ron da tos de mo grá fi cos y con su mo de me di ca men tos po ten cial men te in vo lu cra dos en frac tu ras de ca de ra. Se con si de ró con su - mo de BZD, ha ber las re ci bi do du ran te cin co días pre vios a la frac tu ra. Se cal cu la ron odds ra tios (OR) e in ter va lo de con fian - za 95%. Re sul ta dos: se ob tu vie ron 29 ca sos y 60 con tro les. La me dia de edad (DE) en el gru po ca sos fue de 82,8 (6,4) años y 82,1 (5,2) años en el gru po con trol (p > 0,05). Sexo fe me ni no: 25 (86%) en el gru po ca sos y 49 (82%) en el gru po con trol (p > 0,05). Las BZD fue ron con su mi das por 16/29 (61,5%) ca sos y 13/60 (21,7%) con tro les (p < 0,05). To dos los pa cien tes que con su - mían BZD en am bos gru pos lo hi cie ron por más de seis se ma nas. El OR de frac tu ra de ca de ra en pa cien tes que con su mían BZD fue de 4,5 (IC 95% 1,7-11,6). Con clu sio nes: se des ta ca que las BZD au men tan el ries go de frac tu ra de ca de ra y que se con su men por pe río dos no acon - se ja bles. De ben de sa rro llar se po lí ti cas na cio na les orien ta das al uso ra cio nal de estos medicamentos

RNA silencing is required for Arabidopsis defence against Verticillium wilt disease

RNA silencing is a conserved mechanism in eukaryotes that plays an important role in various biological processes including regulation of gene expression. RNA silencing also plays a role in genome stability and protects plants against invading nucleic acids such as transgenes and viruses. Recently, RNA silencing has been found to play a role in defence against bacterial plant pathogens in Arabidopsis through modulating host defence responses. In this study, it is shown that gene silencing plays a role in plant defence against multicellular microbial pathogens; vascular fungi belonging to the Verticillium genus. Several components of RNA silencing pathways were tested, of which many were found to affect Verticillium defence. Remarkably, no altered defence towards other fungal pathogens that include Alternaria brassicicola, Botrytis cinerea, and Plectosphaerella cucumerina, but also the vascular pathogen Fusarium oxysporum, was recorded. Since the observed differences in Verticillium susceptibility cannot be explained by notable differences in root architecture, it is speculated that the gene silencing mechanisms affect regulation of Verticillium-specific defence responses

A computational-based update on microRNAs and their targets in barley (Hordeum vulgare L.)

<p>Abstract</p> <p>Background</p> <p>Many plant species have been investigated in the last years for the identification and characterization of the corresponding miRNAs, nevertheless extensive studies are not yet available on barley (at the time of this writing). To extend and to update information on miRNAs and their targets in barley and to identify candidate polymorphisms at miRNA target sites, the features of previously known plant miRNAs have been used to systematically search for barley miRNA homologues and targets in the publicly available ESTs database. Matching sequences have then been related to Unigene clusters on which most of this study was based.</p> <p>Results</p> <p>One hundred-fifty-six microRNA mature sequences belonging to 50 miRNA families have been found to significantly match at least one EST sequence in barley. As expected on the basis of phylogenetic relations, miRNAs putatively orthologous to those of <it>Triticum </it>are significantly over-represented inside the set of identified barley microRNA mature sequences. Many previously known and several putatively new miRNA/target pairs have been identified. When the predicted microRNA targets were grouped into functional categories, biological processes previously known to be regulated by miRNAs, such as development and response to biotic and abiotic stress, have been highlighted and most of the target molecular functions were related to transcription regulation. Candidate microRNA coding genes have been reported and genetic variation (SNPs/indels) both in functional regions of putative miRNAs (mature sequence) and at miRNA target sites has been found.</p> <p>Conclusions</p> <p>This study has provided an update of the information on barley miRNAs and their targets representing a foundation for future studies. Many of previously known plant microRNAs have homologues in barley with expected important roles during development, nutrient deprivation, biotic and abiotic stress response and other important physiological processes. Putative polymorphisms at miRNA target sites have been identified and they can represent an interesting source for the identification of functional genetic variability.</p