A population Monte Carlo scheme with transformed weights and its application to stochastic kinetic models

This paper addresses the problem of Monte Carlo approximation of posterior probability distributions. In particular, we have considered a recently proposed technique known as population Monte Carlo (PMC), which is based on an iterative importance sampling approach. An important drawback of this methodology is the degeneracy of the importance weights when the dimension of either the observations or the variables of interest is high. To alleviate this difficulty, we propose a novel method that performs a nonlinear transformation on the importance weights. This operation reduces the weight variation, hence it avoids their degeneracy and increases the efficiency of the importance sampling scheme, specially when drawing from a proposal functions which are poorly adapted to the true posterior. For the sake of illustration, we have applied the proposed algorithm to the estimation of the parameters of a Gaussian mixture model. This is a very simple problem that enables us to clearly show and discuss the main features of the proposed technique. As a practical application, we have also considered the popular (and challenging) problem of estimating the rate parameters of stochastic kinetic models (SKM). SKMs are highly multivariate systems that model molecular interactions in biological and chemical problems. We introduce a particularization of the proposed algorithm to SKMs and present numerical results.Comment: 35 pages, 8 figure

Modelling, Simulation and Fuzzy Self-Tuning Control of D-STATCOM in a Single Machine Infinite Bus Power System

© 2019 Bentham Science Publishers. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.2174/2352096511666180314141205In recent years, demand for electricity has increased considerably, while the expansion of generation and transmission has been very slow due to limited investment in resources and environmental restrictions. Methods: As a result, the power system becomes vulnerable to disturbances and instability. FACTS (Flexible AC Transmission Systems) technology has now been accepted as a potential solution to this problem. This paper deals with the modelling, simulation and fuzzy self-tuning control of a D-STATCOM to enhance the stability and improve the critical fault clearing time(CCT) in a single machine infinite bus (SMIB).A detailed modelling of the D-STATCOM and comprehensive derivation of the fuzzy logic self-tuning control is presented. Results: The dynamic performance of the power system with the proposed control scheme is validated through in a simulation study carried out under Matlab/Simulink and SimPowerSystems toolbox. Conclusion: The results demonstrate a significant enhancement of the power system stability under the simulated fault conditions considered.Peer reviewe

Acute immune signatures and their legacies in severe acute respiratory syndrome coronavirus-2 infected cancer patients

Given the immune system’s importance for cancer surveillance and treatment, we have investigated how it may be affected by SARS-CoV-2 infection of cancer patients. Across some heterogeneity in tumor type, stage, and treatment, virus-exposed solid cancer patients display a dominant impact of SARS-CoV-2, apparent from the resemblance of their immune signatures to those for COVID-19+ non-cancer patients. This is not the case for hematological malignancies, with virus-exposed patients collectively displaying heterogeneous humoral responses, an exhausted T cell phenotype and a high prevalence of prolonged virus shedding. Furthermore, while recovered solid cancer patients’ immunophenotypes resemble those of nonvirus-exposed cancer patients, recovered hematological cancer patients display distinct, lingering immunological legacies. Thus, while solid cancer patients, including those with advanced disease, seem no more at risk of SARS-CoV-2-associated immune dysregulation than the general population, hematological cancer patients show complex immunological consequences of SARS-CoV-2 exposure that might usefully inform their care

Tumor to normal single-cell mRNA comparisons reveal a pan-neuroblastoma cancer cell

Neuroblastoma is a childhood cancer that resembles developmental stages of the neural crest. It is not established what developmental processes neuroblastoma cancer cells represent. Here, we sought to reveal the phenotype of neuroblastoma cancer cells by comparing cancer (n = 19,723) with normal fetal adrenal single-cell transcriptomes (n = 57,972). Our principal finding was that the neuroblastoma cancer cell resembled fetal sympathoblasts, but no other fetal adrenal cell type. The sympathoblastic state was a universal feature of neuroblastoma cells, transcending cell cluster diversity, individual patients, and clinical phenotypes. We substantiated our findings in 650 neuroblastoma bulk transcriptomes and by integrating canonical features of the neuroblastoma genome with transcriptional signals. Overall, our observations indicate that a pan-neuroblastoma cancer cell state exists, which may be attractive for novel immunotherapeutic and targeted avenues

Single cell derived mRNA signals across human kidney tumors.

Funder: Department of HealthTumor cells may share some patterns of gene expression with their cell of origin, providing clues into the differentiation state and origin of cancer. Here, we study the differentiation state and cellular origin of 1300 childhood and adult kidney tumors. Using single cell mRNA reference maps of normal tissues, we quantify reference "cellular signals" in each tumor. Quantifying global differentiation, we find that childhood tumors exhibit fetal cellular signals, replacing the presumption of "fetalness" with a quantitative measure of immaturity. By contrast, in adult cancers our assessment refutes the suggestion of dedifferentiation towards a fetal state in most cases. We find an intimate connection between developmental mesenchymal populations and childhood renal tumors. We demonstrate the diagnostic potential of our approach with a case study of a cryptic renal tumor. Our findings provide a cellular definition of human renal tumors through an approach that is broadly applicable to human cancer

Single cell derived mRNA signals across human kidney tumors.

Tumor cells may share some patterns of gene expression with their cell of origin, providing clues into the differentiation state and origin of cancer. Here, we study the differentiation state and cellular origin of 1300 childhood and adult kidney tumors. Using single cell mRNA reference maps of normal tissues, we quantify reference "cellular signals" in each tumor. Quantifying global differentiation, we find that childhood tumors exhibit fetal cellular signals, replacing the presumption of "fetalness" with a quantitative measure of immaturity. By contrast, in adult cancers our assessment refutes the suggestion of dedifferentiation towards a fetal state in most cases. We find an intimate connection between developmental mesenchymal populations and childhood renal tumors. We demonstrate the diagnostic potential of our approach with a case study of a cryptic renal tumor. Our findings provide a cellular definition of human renal tumors through an approach that is broadly applicable to human cancer

Construyendo un nosotros. Arte interdisciplina y salud mental

Este proyecto de extensión acreditado y financiado por la UNLP, “Taller arte, recreando un nosotros” se propone promover prácticas alternativas de encuentro y participación colectiva para generar vínculos y relaciones no restrictivas entre internados, externados, familias, profesionales y no profesionales, en el Teatro del Hospital Alejandro Korn, utilizando el arte, la expresión, el juego y la estimulación de sentidos. Se sostiene en el proceso de reforma en materia de Salud Mental que se inicia con la Sanción de la Ley Nacional de Salud Mental (Ley Nº 26657) donde se busca continuar con el proceso de desmanicomialización que se viene llevando a cabo en todo el mundo y que registra antecedentes en las normativas internacionales (OPS, 1990; OPS, 2005; OPS, 2010). Se basa en el desplazamiento del eje de la atención brindada en el hospital psiquiátrico hacia estrategias de atención primaria de la salud con base en la comunidad. En los talleres se promueve la acción social concreta. La construcción de saberes se da conjuntamente con todos los involucrados. Actualmente funcionan talleres de radio, arte y expresión, expresión literaria y jardín de sensaciones. Siendo espacios de producción, de aprendizaje, de circulación de la palabra, de compartir con el otro experiencias de vida y opiniones en donde se rescata la subjetividad, la identidad e historicidad. Fuera del hospital se realizan reuniones de planificación y/ contención, trabajando lo emocional y la grupalidad de los talleristas intervinientes. Estos espacios parten del encuentro INTERDISCIPLINAR, quienes participan son de distintas disciplinas tales como psicología, bellas artes, comunicación social, trabajo social, acompañantes terapéuticos, antropología; articulando el trabajo con otros grupos pertenecientes al hospital, instituciones universitarias y otras organizaciones. El trabajo colectivo interdisciplinar se vuelve uno de los pilares así como el ARTE en tanto medio de expresión y no como fin estético. Lo artístico como lenguaje de comunicación, socialización y como herramienta de expansión de la subjetividad en un espacio determinado, un lugar de salud. Desde la continuidad de las actividades y encuentros se producen cambios subjetivos en los participantes. En ese sentido la apuesta es producir una transformación en lo cotidiano de cada uno para que eso sea retomado en los diferentes dispositivos y actores que apuestan a una externación o mejor condición de la persona internada y una mejoría en la salud mental y salud en general. Palabras claves: práctica transformadora, subjetividad, arte, interdisciplina, salud mental