Output controllability analysis of fixed speed wind turbine

This paper deals with a study of output-controllability of a squirrel cage induction generator connected directly to grid. To obtain the Linear Time Invariant System, which describes the generator behavior, are chosen the qd-machine equations and the desired output of the whole system are both the active and reactive power. It is important to remark that whole system equations are linearized assuming steady state point.Preprin

A general approach for computing residues of partial-fraction expansion of transfer matrices

This paper deals with the description of a general method for calculating the residues of a linear system. Considering, physical models, it is well-assumed that the system described only presents simple eigenvalues, or at least simple-complex eigenvalues. However, as demonstrated in this paper, it is not completely true for all the real systems, and a method to evaluate the residues for these cases is required. In this paper, a methodology for computing the residues, even with the existence of multiple eigenvalues (described by their Jordan normal form) is developed and presented. Moreover, the calculation of the residues is applied to analyze the output-controllability of dynamic systems. Finally, some real examples are presented to validate the methodologies proposedPostprint (published version

Input Observability Analysis of Fixed Speed Wind Turbine

This paper deals with the concept of input observability in a fixed speed wind turbine. A linear system has been calculated from the nonlinear equations of the squirrel cage induction generator, supposing it connected directly to the grid and assuming a steady state operating point. The observability of the input from the output of the system could be an interesting way to know if its possible to develop some new controls without introduce special sensors in the system. Furthermore, it is interesting to analyse which is the parameter variation margin of the wind turbine from input-observable state to non-input observable, in order to obtain some restrictions to design future controllers, or limit the operating points.Postprint (published version

Power system stabilizer control for wind power to enhance power system stability

The paper presents a small signal stability analysis for power systems with wind farm interaction. Power systems have damping oscillation modes that can be excited by disturbance or fault in the grid. The power converters of the wind farms can be used to reduce these oscillations and make the system more stable. These ideas are explored to design a power system stabilized (PSS) for a network with conventional generators and a wind farm in order to increase the damping of the oscillation modes. The proposed stabilizer is evaluated by simulation using DigSilent PowerFactoryPostprint (published version

Power system stabiliser capability of offshore wind power plants

Nowadays, wind power generation is being located offshore because of its higher wind speed at lower height and larger installation zones in comparison with onshore technologies. Recently, the concept of wind power plant has been introduced as a result of the increment of wind power penetration in power systems. Transmission system operators are requiring wind power generation to help to power system with some ancillary services such as fault ride through or power system stabiliser capability. Therefore, it is important to study power system stabiliser capability of wind power plants. In this paper, a comparison of various power system stabiliser schemes is presented. The effect of the distance from the shore tie-line to the offshore wind farm on the controller response is also evaluated. These studies show that offshore wind power plants have promising power system stabiliser capability even using local input signals.Postprint (published version

Systematic Review and Meta-Analyses of Aminopeptidases as Prognostic Biomarkers in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the progressive loss of motor neurons in the spinal cord, brain stem, and cerebral cortex. Biomarkers for ALS are essential for disease detection and to provide information on potential therapeutic targets. Aminopeptidases catalyze the cleavage of amino acids from the amino terminus of protein or substrates such as neuropeptides. Since certain aminopeptidases are known to increase the risk of neurodegeneration, such mechanisms may reveal new targets to determine their association with ALS risk and their interest as a diagnostic biomarker. The authors performed a systematic review and meta-analyses of genome-wide association studies (GWASs) to identify reported aminopeptidases genetic loci associated with the risk of ALS. PubMed, Scopus, CINAHL, ISI Web of Science, ProQuest, LILACS, and Cochrane databases were searched to retrieve eligible studies in English or Spanish, published up to 27 January 2023. A total of 16 studies were included in this systematic review, where a series of aminopeptidases could be related to ALS and could be promising biomarkers (DPP1, DPP2, DPP4, LeuAP, pGluAP, and PSA/NPEPPS). The literature reported the association of single-nucleotide polymorphisms (SNPs: rs10260404 and rs17174381) with the risk of ALS. The genetic variation rs10260404 in the DPP6 gene was identified to be highly associated with ALS susceptibility, but meta-analyses of genotypes in five studies in a matched cohort of different ancestry (1873 cases and 1861 control subjects) showed no ALS risk association. Meta-analyses of eight studies for minor allele frequency (MAF) also found no ALS association for the “C” allele. The systematic review identified aminopeptidases as possible biomarkers. However, the meta-analyses for rs1060404 of DPP6 do not show a risk associated with ALS.20 página

Simultaneous inhibition of pan-phosphatidylinositol-3-kinases and MEK as a potential therapeutic strategy in peripheral T-cell lymphomas

Obtained from Haematologica/the Hematology Journal website http://www.haematologica.orgPeripheral T-cell lymphomas are very aggressive hematologic malignancies for which there is no targeted therapy. New, rational approaches are necessary to improve the very poor outcome in these patients. Phosphatidylinositol- 3-kinase is one of the most important pathways in cell survival and proliferation. We hypothesized that phosphatidylinositol- 3-kinase inhibitors could be rationally selected drugs for treating peripheral T-cell lymphomas. Several phosphatidylinositol-3-kinase isoforms were inhibited genetically (using small interfering RNA) and pharmacologically (with CAL-101 and GDC-0941 compounds) in a panel of six peripheral and cutaneous T-cell lymphoma cell lines. Cell viability was measured by intracellular ATP content; apoptosis and cell cycle changes were checked by flow cytometry. Pharmacodynamic biomarkers were assessed by western blot. The PIK3CD gene, which encodes the δ isoform of phosphatidylinositol-3-kinase, was overexpressed in cell lines and primary samples, and correlated with survival pathways. However, neither genetic nor specific pharmacological inhibition of phosphatidylinositol-3-kinase δ affected cell survival. In contrast, the pan-phosphatidylinositol-3-kinase inhibitor GDC-0941 arrested all T-cell lymphoma cell lines in the G1 phase and induced apoptosis in a subset of them. We identified phospho-GSK3b and phospho-p70S6K as potential biomarkers of phosphatidylinositol-3-kinase inhibitors. Interestingly, an increase in ERK phosphorylation was observed in some GDC-0941-treated T-cell lymphoma cell lines, suggesting the presence of a combination of phosphatidylinositol-3-kinase and MEK inhibitors. A highly synergistic effect was found between the two inhibitors, with the combination enhancing cell cycle arrest at G0/G1 in all T-cell lymphoma cell lines, and reducing cell viability in primary tumor T cells ex vivo. These results suggest that the combined treatment of pan-phosphatidylinositol-3-kinase + MEK inhibitors could be more effective than single phosphatidylinositol-3-kinase inhibitor treatment, and therefore, that this combination could be of therapeutic value for treating peripheral and cutaneous T-cell lymphomas.This work was supported by grants from the Asociación Española Contra el Cáncer, Fondo de Investigaciones Sanitarias (PI051623, PI052800 and PI080856), RTICC (RD06/0020/0107) and Ministerio de Ciencia e Innovación (SAF2008-0387-1). EMS is supported by a grant from the Department of Education, Universities and Research of the Basque Government (BFI08.207). MSB is supported by a Contract Miguel Servet from Fondo de Investigaciones Sanitarias (CP11/00018

Dating historical droughts from religious ceremonies, the international pro pluvia rogation database

Climate proxy data are required for improved understanding of climate variability and change in the pre-instrumental period. We present the first international initiative to compile and share information on pro pluvia rogation ceremonies, which is a well-studied proxy of agricultural drought. Currently, the database has more than 3500 dates of celebration of rogation ceremonies, providing information for 153 locations across 11 countries spanning the period from 1333 to 1949. This product provides data for better understanding of the pre-instrumental drought variability, validating natural proxies and model simulations, and multi-proxy rainfall reconstructions, amongst other climatic exercises. The database is freely available and can be easily accessed and visualized via http://inpro.unizar.es/.info:eu-repo/semantics/publishedVersio

A deletion at Adamts9-magi1 Locus is associated with psoriatic arthritis risk

Objective: Copy number variants (CNVs) have been associated with the risk to develop multiple autoimmune diseases. Our objective was to identify CNVs associated with the risk to develop psoriatic arthritis (PsA) using a genome-wide analysis approach. Methods: A total of 835 patients with PsA and 1498 healthy controls were genotyped for CNVs using the Illumina HumanHap610 BeadChip genotyping platform. Genomic CNVs were characterised using CNstream analysis software and analysed for association using the χ2 test. The most significant genomic CNV associations with PsA risk were independently tested in a validation sample of 1133 patients with PsA and 1831 healthy controls. In order to test for the specificity of the variants with PsA aetiology, we also analysed the association to a cohort of 822 patients with purely cutaneous psoriasis (PsC). Results: A total of 165 common CNVs were identified in the genome-wide analysis. We found a highly significant association of an intergenic deletion between ADAMTS9 and MAGI1 genes on chromosome 3p14.1 (p=0.00014). Using the independent patient and control cohort, we validated the association between ADAMTS9-MAGI1 deletion and PsA risk (p=0.032). Using next-generation sequencing, we characterised the 26 kb associated deletion. Finally, analysing the PsC cohort we found a lower frequency of the deletion compared with the PsA cohort (p=0.0088) and a similar frequency to that of healthy controls (p>0.3). Conclusions: The present genome-wide scan for CNVs associated with PsA risk has identified a new deletion associated with disease risk and which is also differential from PsC risk

Artistas sobre outras obras

A pós modernidade encerra a interrogação crítica do homem sobre o homem: a linguagem ameaça o que é significante, o que é corpo. O sujeito é falado, e assim constituído depois da linguagem (Althusser, 1976). O jovem Arthur Rimbaud sintetiza-o, aos dezassete anos, numa carta ao seu professor de retórica Georges Izambard, datada de 13 de maio 1871: «C’est faux de dire: je pense: on devrait dire on me pense. Pardon du jeu de mots. Je est un autre». (Rimbaud, 1999: 237) A identidade resiste à linguagem dos homens. A linguagem é transmitida entre as gerações e com ela transporta os sujeitos, ou, o que é dizer o mesmo, a possível interrogação: quem me fala? É esta também a perplexidade que motivou o tema desta revista Estúdio. Reuniram-se, nesta edição, 22 artigos, provenientes de diferentes autores da Argentina, Brasil, Portugal e Espanha, que se debruçam sobre artistas cuja identidade se mostra e merece ser interrogada: são espaços ‘ex-cêntricos,’ para se descobrir.info:eu-repo/semantics/publishedVersio