94 research outputs found

    Symmetrical and unsymmetrical voltage sag effects on the three-phase synchronous machine stability

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    This paper focuses on the effects of voltage sags, both symmetrical and unsymmetrical, on the three-phase Synchronous Machine (SM). Voltage sags on SM cause speed variations, current and torque peaks and hence may cause tripping and equipment damage. The consequences of voltage sags on the machine behaviour depend on different factors such as sag’s magnitude (or depth), duration, initial point-on-wave and the parameters of the electrical machine. In this study, three SMs of different rated power have been considered in order to simulate the voltage sag effects for specific conditions and analyze the machine stability.Postprint (published version

    Early Nutrition and Later Excess Adiposity during Childhood: A Narrative Review

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    Background: Studies on childhood obesity mainly focus on the genetic component and on the lifestyle that may be associated with the development of obesity. However, the study of perinatal factors in their programming effect toward future obesity in children or adults is somewhat more recent, and there are still mechanisms to be disentangled. Summary: In this narrative review, a comprehensive route based on the influence of some early factors in life in the contribution to later obesity development is presented. Maternal pre-pregnancy BMI and gestational weight gain have been pointed out as independent determinants of infant later adiposity. Lifestyle interventions could have an impact on pregnant mothers through epigenetic mechanisms capable of redirecting the genetic expression of their children toward a future healthy weight and body composition and dietary-related microbiome modifications in mothers and newborns might also be related. After birth, infant feeding during the first months of life is directly associated with its body composition and nutritional status. From this point of view, all the expert committees in the world are committed to promote exclusive breastfeeding up to 6 months of age and to continue at least until the first year of life together with complementary feeding based on healthy dietary patterns such as Mediterranean Diet

    Prótesis metálica autoexpandible en el tratamiento de la estenosis del colédoco postrasplante de hígado en un niño. A propósito de un caso

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    ResumenLas estenosis benignas de la vía biliar son debidas a lesión de esta por manejo quirúrgico, traumatismos o por inflamación. El manejo en la actualidad es por vía endoscópica mediante dilataciones, colocación de prótesis plásticas y más recientemente con las prótesis autoexpandibles totalmente cubiertas. Se presenta el caso de una menor de 7 años a la que se realizó trasplante de hígado y presentó una estenosis a nivel de la colédoco-colédoco anastomosis en donde se utilizó una prótesis metálica totalmente cubierta autoexpandible con buenos resultados.AbstractBenign biliary strictures are due to injury by surgical operation, trauma or inflammation, is currently handling by endoscopy with dilation, placement of plastic stents and more recently with fully covered self-expanding prosthesis; the case of a child under 7 years that liver transplantation was performed and presented a stenosis at the level of the coledoco-coledoco anastomosis where a fully covered self-expandable metal stent was used with good results is presented

    A comparison of back propagation and Generalized Regression Neural Networks performance in neutron spectrometry

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    The process of unfolding the neutron energy spectrum has been subject of research for many years. Monte Carlo, iterative methods, the bayesian theory, the principle of maximum entropy are some of the methods used. The drawbacks associated with traditional unfolding procedures have motivated the research of complementary approaches. Back Propagation Neural Networks (BPNN), have been applied with success in neutron spectrometry and dosimetry domains, however, the structure and learning parameters are factors that highly impact in the networks performance. In ANN domain, Generalized Regression Neural Network (GRNN) is one of the simplest neural networks in term of network architecture and learning algorithm. The learning is instantaneous, requiring no time for training. Opposite to BPNN, a GRNN would be formed instantly with just a 1-pass training on the development data. In the network development phase, the only hurdle is to optimize the hyper-parameter, which is known as sigma, governing the smoothness of the network. The aim of this work was to compare the performance of BPNN and GRNN in the solution of the neutron spectrometry problem. From results obtained it can be observed that despite the very similar results, GRNN performs better than BPNN

    Desarrollo de un experimento virtual para la enseñanza a distancia de tópicos de ingeniería química: descarga de un tanque

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    Se presenta el desarrollo de un espacio de trabajo virtual inmersivo en el que tanto profesores como alumnos pueden interactuar al mismo tiempo con los contenidos elaborados con base en el guion experimental de una práctica de descarga de tanques que se realiza normalmente en laboratorio físico; la finalidad del trabajo es permitir continuar con la educación a distancia, con la mayor aproximación posible a un laboratorio real, cuando las situaciones compliquen acceder presencialmente a los espacios educativos. Se desarrollaron los modelos tridimensionales del equipo requerido en el guion experimental, así como los elementos gráficos que permitieran representar el contenido del tanque; así también se programaron las interacciones requeridas, y se realizó el despliegue del experimento en una plataforma virtual, probando el correcto acceso de usuarios y de operación del experimento.Development of a virtual workspace is presented, in which professors along students will be able to interact at the same time with the content based on a experimental script of a tank discharge practice that is carry out usually in a physical laboratory; the aim of this work is to allow continue with remote education, as real as possible to a real laboratory, even if circumstances avoid to be physically in an academic space. Tridimensional models of the required equipment were developed, as the graphic models that allowed to represent tank contents; interactions were programmed and also the development was deployed on a virtual platform testing users correct access and operation of the experiment

    Rituximab in the treatment of interstitial lung disease associated with autoimmune diseases: experience from a single referral center and literature review

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    ABSTRACT: In the present study, we aimed to report our experience with rituximab (RTX) in the treatment of patients with ILD associated with AD (AD-ILD) at a single center. For this purpose, clinical characteristics, radiological findings, and pulmonary function tests (PFTs) of RTX-treated AD-ILD-patients seen from May 2016 until March 2020 at a referral center for individuals with ILD were retrospectively reviewed. Additionally, an updated literature review was conducted. A total of 26 patients (mean age 58.3 ± 11.1 years at ILD diagnosis) was included. The most common ADs related to ILD were systemic sclerosis, idiopathic inflammatory myositis (including anti-synthetase syndrome) and rheumatoid arthritis. Non-specific interstitial pneumonia (n = 12) and usual interstitial pneumonia (n = 11) were the predominant radiological patterns. The sustained improvement in PFTs was observed from the start of RTX, with a statistically significant increase in DLCO from basal to one year after RTX (mean + 4.2%, p = 0.024). Overall, there were no differences when comparing PFT outcome according to the radiological pattern or the specific type of AD. In conclusion, RTX constitutes a good therapeutic option to preserve lung function in patients with AD-ILD, regardless of the radiological pattern or the underlying AD.This research received no external funding. B.A.-M. is recipient of a and “López Albo” Post-Residency Programme funded by Servicio Cántabro de Salud. S.R.-M. is supported by funds of the RETICS Program (RD16/0012/0009) (Instituto de Salud Carlos III, co-funded by the European Regional Development Fund)

    A neutron spectrum unfolding code based on generalized regression artificial neural networks

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    The most delicate part of neutron spectrometry, is the unfolding process. The derivation of the spectral information is not simple because the unknown is not given directly as a result of the measurements. Novel methods based on Artificial Neural Networks have been widely investigated. In prior works, back propagation neural networks (BPNN) have been used to solve the neutron spectrometry problem, however, some drawbacks still exist using this kind of neural nets, i.e. the optimum selection of the network topology and the long training time. Compared to BPNN, it's usually much faster to train a generalized regression neural network (GRNN). That's mainly because spread constant is the only parameter used in GRNN. Another feature is that the network will converge to a global minimum, provided that the optimal values of spread has been determined and that the dataset adequately represents the problem space. In addition, GRNN are often more accurate than BPNN in the prediction. These characteristics make GRNNs to be of great interest in the neutron spectrometry domain. This work presents a computational tool based on GRNN capable to solve the neutron spectrometry problem. This computational code, automates the pre-processing, training and testing stages using a k-fold cross validation of 3 folds, the statistical analysis and the post-processing of the information, using 7 Bonner spheres rate counts as only entrance data. The code was designed for a Bonner Spheres System based on a LiI(Eu) neutron detector and a response matrix expressed in 60 energy bins taken from an International Atomic Energy Agency compilation

    The Spectrum of Interstitial Lung Disease Associated With Autoimmune Diseases: Data of a 3.6-Year Prospective Study From a Referral Center of Interstitial Lung Disease and Lung Transplantation

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    Interstitial lung disease (ILD) may occur in patients with a rheumatic autoimmune disease (AD), increasing their risk of morbidity and mortality. However, little is known about the prevalence of AD in patients diagnosed with an ILD. In this prospective study, we determined the spectrum of ILD associated with AD (AD-ILD) among patients sent for assessment to a single clinic of ILD and lung transplantation from a referral center between May 2016 and December 2019. ILD diagnosis was made by pneumologists based on clinical and radiological findings and pulmonary function test abnormalities. All patients with ILD were also assessed by experienced rheumatologists. During the period of assessment, 338 patients were diagnosed with ILD. Among them, 32.8% fulfilled definitions for an AD. Most cases with AD-ILD had a diagnosis of rheumatoid arthritis (27.0%), systemic sclerosis (26.1%) or anti-synthetase syndrome (17.1%). Interestingly, 18% of the patients with AD-ILD were diagnosed as having an interstitial pneumonia with autoimmune features. Antinuclear antibodies and non-specific interstitial pneumonia were the most frequent positive autoantibodies and radiological pattern found in AD-ILD patients, respectively. In conclusion, our study indicates that a high number of ILD patients have a related AD. Consequently, close collaboration among rheumatologists and pneumologists is needed.This research received no external funding. SR-M is supported by funds of the RETICS Program (RD16/0012/0009) (Instituto de Salud Carlos III, co-funded by the European Regional Development Fund)

    DUbbing language-therapy CINEma-based in aphasia post-stroke (DULCINEA): study protocol for a randomized crossover pilot trial

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    Communication is one of the most important predictors of social reintegration after stroke. Approximately 15–42% of stroke survivors experience post-stroke aphasia. Helping people recover from aphasia is one of the research priorities after a stroke. Our aim is to develop and validate a new therapy integrating dubbing techniques to improve functional communication. Methods: The research project is structured as three work packages (WP). WP1: development of the dubbed language cinema-based therapy: Two research assistants (a speech therapist and a dubbing actor) will select the clips, mute specific words/sentences in progressive speech difficulty, and guide patients to dub them across sessions. Words to be dubbed will be those considered to be functionally meaningful by a representative sample of aphasic patients and relatives through an online survey. WP2: a randomized, crossover, interventional pilot study with the inclusion of 54 patients with post-stroke non-fluent aphasia. Patients will be treated individually in 40-min sessions twice per week for 8 weeks. Primary outcomes will be significant pre/post differences in scores in the Communicative Activity Log (CAL) questionnaire and Boston Diagnostic Aphasia Examination (BDAE) administered by a psychologist blinded to the patients’ clinical characteristics. Secondary outcomes: General Health Questionnaire (GHQ)-12, Stroke Aphasia Quality of Life Scale (SAQOL-39), Western Aphasia Battery Revised (WAB-R), and the Stroke Aphasic Depression Questionnaire (SADQ10). WP3: educational activities and dissemination of results. WP3 includes educational activities to improve public knowledge of aphasia and dissemination of the results, with the participation of the Spanish patients’ association Afasia Activa. Discussion: This pilot clinical trial will explore the efficacy of a new therapeutic tool based on dubbing techniques and computer technology to improve functional communication of patients suffering from post-stroke aphasia with the use of standardized test assessmentThis study is promoted by Blanca Fuentes and the Research Foundation of La Paz University Hospital, which hosts a research consortium joined by the Department of Neurology at La Paz University Hospital, the Department of Psychology at Comillas Pontifical University, and the patients’ association Afasia Activa. This project has received funding from “la Caixa” Banking Foundation under the project code HR18-00026. Funder is not involved in any of the following processes: design of the trial, data collection, analysis, or interpretation of data nor than in writing the manuscrip

    Pancreatic metastases from renal cell carcinoma. Postoperative outcome after surgical treatment in a Spanish multicenter study (PANMEKID)

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    Background: Renal Cell Carcinoma (RCC) occasionally spreads to the pancreas. The purpose of our study is to evaluate the short and long-term results of a multicenter series in order to determine the effect of surgical treatment on the prognosis of these patients. Methods: Multicenter retrospective study of patients undergoing surgery for RCC pancreatic metastases, from January 2010 to May 2020. Variables related to the primary tumor, demographics, clinical characteristics of metastasis, location in the pancreas, type of pancreatic resection performed and data on short and long-term evolution after pancreatic resection were collected. Results: The study included 116 patients. The mean time between nephrectomy and pancreatic metastases' resection was 87.35 months (ICR: 1.51-332.55). Distal pancreatectomy was the most performed technique employed (50 %). Postoperative morbidity was observed in 60.9 % of cases (Clavien-Dindo greater than IIIa in 14 %). The median follow-up time was 43 months (13-78). Overall survival (OS) rates at 1, 3, and 5 years were 96 %, 88 %, and 83 %, respectively. The disease-free survival (DFS) rate at 1, 3, and 5 years was 73 %, 49 %, and 35 %, respectively. Significant prognostic factors of relapse were a disease free interval of less than 10 years (2.05 [1.13-3.72], p 0.02) and a history of previous extrapancreatic metastasis (2.44 [1.22-4.86], p 0.01). Conclusions: Pancreatic resection if metastatic RCC is found in the pancreas is warranted to achieve higher overall survival and disease-free survival, even if extrapancreatic metastases were previously removed. The existence of intrapancreatic multifocal compromise does not always warrant the performance of a total pancreatectomy in order to improve survival
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