Laurent expansion of the inverse of perturbed, singular matrices

In this paper we describe a numerical algorithm to compute the Laurent expansion of the inverse of singularly perturbed matrices. The algorithm is based on the resolvent formalism used in complex analysis to study the spectrum of matrices. The input of the algorithm are the matrix coefficients of the power series expansion of the perturbed matrix. The matrix coefficients of the Laurent expansion of the inverse are computed using recursive analytical formulae. We show that the computational complexity of the proposed algorithm grows algebraically with the size of the matrix, but exponentially with the order of the singularity. We apply this algorithm to several matrices that arise in applications. We make special emphasis to interpolation problems with radial basis functions.This work has been supported by Spanish MICINN Grants FIS2013-41802-R and CSD2010-00011

Laurent series based RBF-FD method to avoid ill-conditioning

We propose a new approach to avoid the inherent ill-condition in the computation of RBF-FD weights, which is due to the fact that the RBF interpolation matrix is nearly singular. The new approach is based on the semi-analytical computation of the Laurent series of the inverse of the RBF interpolation matrix. Once the Laurent series is obtained, it can be used to compute the RBF-FD weights of any differential operator exactly without extra cost. The proposed method also provides analytical formulas for the RBF-FD weights in terms of the parameters involved in the problem. These formulas can be used to derive the exact dependence of the truncation error in the approximation of any differential operator of a given function. Furthermore, from the analysis presented here one can derive the values of the parameters involved in the problem for which the RBF interpolation matrix becomes ill-conditioned and, hence, for which the weights cannot be obtained numerically

Reporte de sostenibilidad como herramienta de gestión – Pro Avance SAC.

La presente tesis recopila y analiza los conocimientos recibidos a lo largo del programa de Maestría en Dirección de Empresa (MBA), mediante su aplicación en una empresa de la ciudad de Arequipa; con el propósito de identificar el problema clave de la empresa, comprender y analizar la información externa e interna de la organización y sostener una propuesta que busque solucionar esta problemática. En tal sentido, el documento toma como fuente de información los datos de la empresa Pro avance. Pro avance es una organización con más de 16 años de trayectoria operando en la ciudad de Arequipa desde el 2003, fundada por sus socios, Sres. Edith Choque y Armando Romero, como un Centro de Educación Técnica Productiva (CETPRO), que brinda los servicios de capacitación y consultoría. Asimismo, la organización cuenta con una inmueble moderno, ubicada en el distrito de Yanahuara y que cumple con los principales protocolos de seguridad que le ha permitido ser reconocida y certificada bajo esta calificación. Del mismo modo, a lo largo de los años, Pro avance ha tratado de adaptarse a la vanguardia de un buen servicio educativo, mediante el uso de la tecnología; sin embargo, como toda pequeña empresa, tiene grandes retos por delante para seguir incrementando su presencia y su crecimiento. Pro avance entiende como desarrollo sostenible el tener un crecimiento económico, social y ambiental, con un nivel de confianza y compromiso con los grupos de interés. Por tal motivo, la compañía monitorea, de manera continua, las directrices de su reporte de sostenibilidad, a fin de identificar sus impactos y encontrar las soluciones o planes de acción para su mitigación. Pro avance participa del programa de negocios competitivos de Global Reporting Initiative (GRI) desarrollando sus reportes conforme a dichos estándares. En consecuencia, este documento presenta la siguiente estructura de análisis: (a) Situación general de la organización, (b) problema clave de la organización, (c) revisión de la literatura, (d) análisis cualitativo y cuantitativo de la empresa, (e) análisis de causa raíz del problema, (f) alternativas de soluciones evaluadas, (g) solución propuesta, (h) plan de implementación y factores de éxito, y (g) resultado esperados. Cabe mencionar, que el reporte está acompañado de conclusiones, recomendaciones y anexos que complementan la información de la propuesta.This thesis compiles and analyzes the knowledge received throughout the Master of Business Administration (MBA), through its application in a company in the city of Arequipa; with the purpose of identifying the key problem of the company, understanding and analyzing the external and internal information of the organization and supporting a proposal that seeks to solve this problem. In this sense, the document takes as a source of information the data of the Pro Avance company. Pro Advance is an organization with more than 16 years of experience operating in the city of Arequipa since 2003, founded by its partners, Edith Choque and Armando Romero, as a Center for Productive Technical Education (CETPRO), which provides services training and consulting. Likewise, the organization has a modern property, located in the Yanahuara district and that complies with the main security protocols that has allowed it to be recognized and certified under this qualification. Similarly, over the years, Pro Advance has tried to adapt to the forefront of a good educational service, through the use of technology; However, like any small business, it has great challenges ahead to continue increasing its presence and growth. Pro Avance understands sustainable development as having economic, social and environmental growth, with a level of trust and commitment to stakeholders. For this reason, the company continuously monitors the guidelines of its sustainability report, in order to identify its impacts and find solutions or action plans for their mitigation. Pro Avance participates in the Global Reporting Initiative (GRI) competitive business program, developing its reports in accordance with these standards. Consequently, this document presents the following analysis structure: (a) General situation of the organization, (b) key problem of the organization, (c) review of the literature, (d) qualitative and quantitative analysis of the company, (e) root cause analysis of the problem, (f) alternative solutions evaluated, (g) proposed solution, (h) implementation plan and success factors, and (g) expected results. It is worth mentioning that the report is accompanied by conclusions, recommendations and annexes that complement the information in the proposal

Anti-proliferative effect of extremely low frequency electromagnetic field on preneoplastic lesions formation in the rat liver

<p>Abstract</p> <p>Background</p> <p>Recently, extremely low frequency electromagnetic fields (ELF-EMF) have been studied with great interest due to their possible effects on human health. In this study, we evaluated the effect of 4.5 mT - 120 Hz ELF-EMF on the development of preneoplastic lesions in experimental hepatocarcinogenesis.</p> <p>Methods</p> <p>Male Fischer-344 rats were subjected to the modified resistant hepatocyte model and were exposed to 4.5 mT - 120 Hz ELF-EMF. The effects of the ELF-EMF on hepatocarcinogenesis, apoptosis, proliferation and cell cycle progression were evaluated by histochemical, TUNEL assay, caspase 3 levels, immunohistochemical and western blot analyses.</p> <p>Results</p> <p>The application of the ELF-EMF resulted in a decrease of more than 50% of the number and the area of γ-glutamyl transpeptidase-positive preneoplastic lesions (<it>P </it>= 0.01 and <it>P </it>= 0.03, respectively) and glutathione S-transferase placental expression (<it>P </it>= 0.01). The number of TUNEL-positive cells and the cleaved caspase 3 levels were unaffected; however, the proliferating cell nuclear antigen, Ki-67, and cyclin D1 expression decreased significantly (<it>P </it>≤ 0.03), as compared to the sham-exposure group.</p> <p>Conclusion</p> <p>The application of 4.5 mT - 120 Hz ELF-EMF inhibits preneoplastic lesions chemically induced in the rat liver through the reduction of cell proliferation, without altering the apoptosis process.</p

Cost-effectiveness analysis of an active search to retrieve HCV patients lost to follow-up (RELINK-C strategy) and the impact of COVID-19

Acord transformatiu CRUE-CSICAltres ajuts: Gilead Science

Steroid hormone-related polymorphisms associate with the development of bone erosions in rheumatoid arthritis and help to predict disease progression: Results from the REPAIR consortium

Here, we assessed whether 41 SNPs within steroid hormone genes associated with erosive disease. The most relevant finding was the rheumatoid factor (RF)-specific effect of the CYP1B1, CYP2C9, ESR2, FcγR3A, and SHBG SNPs to modulate the risk of bone erosions (P = 0.004, 0.0007, 0.0002, 0.013 and 0.015) that was confirmed through meta-analysis of our data with those from the DREAM registry (P = 0.000081, 0.0022, 0.00074, 0.0067 and 0.0087, respectively). Mechanistically, we also found a gender-specific correlation of the CYP2C9rs1799853T/T genotype with serum vitamin D3 levels (P = 0.00085) and a modest effect on IL1β levels after stimulation of PBMCs or blood with LPS and PHA (P = 0.0057 and P = 0.0058). An overall haplotype analysis also showed an association of 3 ESR1 haplotypes with a reduced risk of erosive arthritis (P = 0.009, P = 0.002, and P = 0.002). Furthermore, we observed that the ESR2, ESR1 and FcγR3A SNPs influenced the immune response after stimulation of PBMCs or macrophages with LPS or Pam3Cys (P = 0.002, 0.0008, 0.0011 and 1.97•10−7). Finally, we found that a model built with steroid hormone-related SNPs significantly improved the prediction of erosive disease in seropositive patients (PRF+ = 2.46•10−8) whereas no prediction was detected in seronegative patients (PRF− = 0.36). Although the predictive ability of the model was substantially lower in the replication population (PRF+ = 0.014), we could confirm that CYP1B1 and CYP2C9 SNPs help to predict erosive disease in seropositive patients. These results are the first to suggest a RF-specific association of steroid hormone-related polymorphisms with erosive disease

Influence of elevated-CRP level-related polymorphisms in non-rheumatic Caucasians on the risk of subclinical atherosclerosis and cardiovascular disease in rheumatoid arthritis

Association between elevated C-reactive protein (CRP) serum levels and subclinical atherosclerosis and cardiovascular (CV) events was described in rheumatoid arthritis (RA). CRP, HNF1A, LEPR, GCKR, NLRP3, IL1F10, PPP1R3B, ASCL1, HNF4A and SALL1 exert an influence on elevated CRP serum levels in non-rheumatic Caucasians. Consequently, we evaluated the potential role of these genes in the development of CV events and subclinical atherosclerosis in RA patients. Three tag CRP polymorphisms and HNF1A, LEPR, GCKR, NLRP3, IL1F10, PPP1R3B, ASCL1, HNF4A and SALL1 were genotyped in 2,313 Spanish patients by TaqMan. Subclinical atherosclerosis was determined in 1,298 of them by carotid ultrasonography (by assessment of carotid intima-media thickness-cIMT-and presence/absence of carotid plaques). CRP serum levels at diagnosis and at the time of carotid ultrasonography were measured in 1,662 and 1,193 patients, respectively, by immunoturbidimetry. Interestingly, a relationship between CRP and CRP serum levels at diagnosis and at the time of the carotid ultrasonography was disclosed. However, no statistically significant differences were found when CRP, HNF1A, LEPR, GCKR, NLRP3, IL1F10, PPP1R3B, ASCL1, HNF4A and SALL1 were evaluated according to the presence/absence of CV events, carotid plaques and cIMT after adjustment. Our results do not confirm an association between these genes and CV disease in RA

Vertebrate populations' trends across the Iberian Peninsula

Resumen del trabajo presentado a: 2nd Meeting of the Iberian Ecological Society (SIBECOL); XXI conference of the Iberian Association of Limnology (AIL) and 21st National Congress of Ecology of the Portuguese Ecological Society (SPECO), celebrados en Aveiro (Portugal) del 3 al 8 de julio de 2022.Understanding and identifying the impacts of multiple stressors on natural populations has become a key objective for post-2020 biodiversity conservation. Of particular concern are the impacts of stressors at the local scale, which are not necessarily reflected in current global conservation assessments. As a hotspot of biodiversity, the Iberian Peninsula is an area of special interest for conservation, but it is currently facing myriad environmental problems. Yet, a synthesis of the impacts of multiple stressors on the Iberian faunal populations is glaringly missing. To contribute to this challenge, we join our efforts in an Early Career Researchers project funded by SIBECOL, which aims to synthesise current knowledge on population trends of Iberian marine, terrestrial and freshwater vertebrates, and, eventually, to identify the most common stressors for Iberian fauna populations, and their differences between major taxonomic groups and ecosystems. Here, we will present the results of the first phase of this project, whose objective was to describe the trends of Iberian vertebrate populations and identify knowledge gaps related to taxonomic groups and ecosystems. To that aim, we conducted an extensive literature review, with more than 5,000 scientific manuscripts and grey literature screened. From this initial review, and after applying data quality controls, we obtained > 1,000 population time series of Iberian vertebrates across marine, terrestrial, and freshwater ecosystems. Once we compiled this database, we analysed the population trends using a two-step modelling process: (i) first, we applied state-space models to derive the population trend of each population time series; and (ii) second, we used multilevel Bayesian models to determine the factors influencing these population trends. Overall, we found that Iberian vertebrate populations display a disparity in trends, with both declines and increases, with fishes (both marine and freshwater) being the taxa showing clear signs of decline. Additionally, we identified important gaps in monitoring data across the Iberian Peninsula, with amphibians and reptiles severely underrepresented in our dataset, despite being among the most threatened taxonomic groups. These gaps may limit our understanding of the impacts of stressors at local scales and eventually bias current conservation assessments. Overall, our approach will bridge the significant gap in our knowledge between the global and local scale conservation status of wild Iberian populations and help focus future conservation policies.Peer reviewe