A comparative study of alternative approaches for common factors identification

Preliminary versionFor multivariate non-stationary time series modeling is essential to know the number of common factors that define the behavior of the series. The traditional way to approach this problem is to study the cointegration relations among data through tests of the trace or maximum eigenvalue, obtaining the number of stationary long-run relations. Alternatively this problem can be analyzed using dynamic factor models as in Peña and Poncela (2006), estimating in this case the number of all independent common factors, stationary or not, that describe the behavior of data. In this context, we analyze empirically the power of such alternative approaches by applying them to series simulated using known factorial models. The results show that when there are stationary common factors, when the number of observations is reduced and/or when the series have involved more than one cointegration relation, the common factor test is more powerful than the usual cointegration tests. These results together with the greater flexibility of dynamic factor models for identify the load matrix of the DGP make them more suitable for use in multivariate analysis

Problemática contable de los títulos con rendimiento implícito

Accésit Premio Estudios Financieros 1995 El objetivo del presente estudio es el de encontrar una posible solución económica, financiera y contable al problema que surge de la Norma 8.ª de Valoración del PGC, como consecuencia del tratamiento asimétrico del rendimiento explícito e implícito de los valores de renta fija

Liquidity measures for bonds selection to estimate the interest rate curve: Spanish case

The European Insurance and Occupational Pensions Authority establishes that the estimation of the interest rate curve, used for the valuation of insurance company operations, should consider all liquid bonds; in particular, for the euro zone, if fixes bonds with maturity up to 20 years as the last liquid point. The financial literature has analyzed the different components of liquidity (rigidity, immediacy, breadth, resilience and depth) and it has found a significant relationship between the return-risk binomial and liquidity. This paper searches for the liquidity indicators correlated with bond yield and risk, in order to select the last liquid point. On a daily data sample of the Spanish public debt market we find that, up to one month, the indicators of depth

Curvas y superficies con Matlab

Sabemos que las curvas y superficies son objetos representables en el plano y en el espacio tridimensional mediante funciones de una sola variable o de dos variables. La representación gráfica en las computadoras facilita el estudio de las curvas y superficies. Mostraremos gráficamente las rectas tangentes a las curvas tanto en el plano como en el espacio tridimensional, así como los planos tangentes a las superficies y las curvas de nivel

Stability and Predictors of Poor 6-min Walking Test Performance over 2 Years in Patients with COPD

©2020. This manuscript version is made available under the CC-BY 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This document is the Published, version of a Published Work that appeared in final form in Journal of Clinical Medicine (JCM). To access the final edited and published work see https://doi.org/10.3390/jcm9041155Poor performance in the 6-min walk test (6MWT < 350 m) is an important prognostic indicator of mortality and risk of exacerbations in patients with chronic obstructive pulmonary disease (COPD). Little is known about the stability of this state over time and what factors might predict a poor 6MWT performance. To determine the stability of 6MWT performance over a 2-year period in COPD patients participating in annual medical follow-up visits, and to assess the ability of several clinical, pulmonary, and non-pulmonary factors to predict poor 6MWT performance, we prospectively included 137 patients with stable COPD (mean age, 66.9 8.3 years). The 6MWT was scored at baseline and 2-year follow-up. To evaluate clinical, pulmonary, and non-pulmonary variables as potential predictors of poor 6MWT performance, we used multiple logistic regression models adjusted for age, sex, weight, height, and 6MWT performance at baseline. Poor 6MWT performance was stable over 2 years for 67.4% of patients. Predictors of poor 6MWT performance included a five-repetition sit-to-stand test score 2 (OR, 3.01; 95% CI, 1.22–7.42), the percentage of mobility activities with limitations (OR, 1.03; 95% CI, 1.00–1.07), and poor 6MWT performance at baseline (OR, 4.64; 95% CI, 1.88–11.43). Poor 6MWT performance status was stable for the majority of COPD patients. Lower scores on the five-repetition sit-to-stand test and a higher number of mobility activities with limitations were relevant predictors of poor 6MWT performance over 2 years. Prognostic models based on these non-pulmonary factors can provide non-inferior discriminative ability in comparison with prognostic models based on only pulmonary factors

Eph/ephrin Signaling and Biology of Mesenchymal Stromal/Stem Cells

Mesenchymal stromal/stem cells (MSCs) have emerged as important therapeutic agents, owing to their easy isolation and culture, and their remarkable immunomodulatory and anti-inflammatory properties. However, MSCs constitute a heterogeneous cell population which does not express specific cell markers and has important problems for in vivo homing, and factors regulating their survival, proliferation, and differentiation are largely unknown. Accordingly, in the present article, we review the current evidence on the relationships between Eph kinase receptors, their ephrin ligands, and MSCs. These molecules are involved in the adult homeostasis of numerous tissues, and we and other authors have demonstrated their expression in human and murine MSCs derived from both bone marrow and adipose tissue, as well as their involvement in the MSC biology. We extend these studies providing new results on the effects of Eph/ephrins in the differentiation and immunomodulatory properties of MSC

La epidemia de tercianas de 1786 en la antigua provincia de Toledo

After revising the few contributions to the history of medicine that have been published with regard to the province of Toledo and medical literature on tertian fever in the second half of the eighteenth century, the article concentrates on describing the general situation existing between 1785 and 1787, with the help of the «Historical account ...» of P. Escolano; there follows an examination of the causes of the tertian fever suffered in the province of Toledo and the development of the epidemic during that time, with special reference to the town of Escalona. The incidence is compared by districts, and the consequences of the epidemic scourge. There is also an appendix; listing all the towns in the province of Toledo, with the number of inhabitants, tertian fever sufferers, those who died from the disease and malarial morbidity and mortality.Tras un repaso a las pocas aportaciones que sobre historia de la medicina se han publicado relativas a la provincia de Toledo y a la literatura médica sobre tercianas en la segunda mitad del siglo XVIII, el artículo se centra en describir la situación general existente entre 1785-1787 con la ayuda de la Relación histórica… de P. Escolano; después prosigue con el examen de las causas de las tercianas padecidas en la provincia de Toledo y el desarrollo de la epidemia en esos años, deteniéndonos particularmente en la villa de Escalona. Se compara su incidencia por partidos para terminar con los métodos curativos y las consecuencias del azote epidémico. Además se incluye un apéndice en el que se relacionan todas las poblaciones de la provincia de Toledo, con su número de habitantes, enfermos tercianarios, fallecidos tercianarios y la morbilidad y mortalidad palúdica

El sector emprendedor de las TIC, el comercio electrónico y la colaboración con usuarios: efectos sobre el resultado innovador de la empresa

pp. 87-102El extraordinario avance que han experimentado las tecnologías de la información y las comunicaciones (TIC) durante las últimas décadas y la enorme variedad de sus aplicaciones ha provocado importantes cambios sociales y económicos. Sus efectos no solo afectan a las empresas que las emplean, sino que también repercuten sobre el conjunto del sistema económico.S

Reactivity with Electrophiles of Imido Groups Supported on Trinuclear Titanium Systems

Several trinuclear titanium complexes bearingamido mu-NHR, imido mu-NR, and nitrido mu(n)-N ligands have been prepared by reaction of [{Ti(eta(5)-C5Me5)(mu-NH)}(3)(mu(3)-N)] (1) with 1 equiv of electrophilic reagents ROTf (R = H, Me, SiMe3; OTf = OSO2CF3). Treatment of 1 with triflic acid or methyl triflate in toluene at room temperature affords the precipitation of compounds [Ti-3(eta(5)-C5Me5)(3)(mu(3)-N)(mu-NH)(2)(mu-NH2)(OTf)] (2) or [Ti-3(eta(5)-C5Me5)(3)(mu(3)-N)(mu-NH)(mu-NH2)(mu-NMe)(OTf)](3). Complexes 2 and 3 exhibit a fluxional behavior in solution consisting of proton exchange between mu-NH2 and mu-NH groups, assisted by the triflato ligand, as could be inferred from a dynamic NMR spectroscopy study. Monitoring by NMR spectroscopy the reaction course. of 1 with MeOTf allows the characterization of the methylamido intermediate [Ti-3(eta(5)-C5Me5)(3)(mu(3)-N)(mu-NH)(2)(mu-NHMe)(OTf)] (4), which readily rearranges to give 3 by a proton migration from the NHMe amido group to the NH imido ligands. The treatment of 1 with 1 equiv ofMe3SiOTf produces the stable ionic complex [Ti-3(eta(5)-C5Me5)(3)(mu(3)-N)(mu-NH)(2)(mu-NHSiMe3)][OTf] (5) with a disposition of the nitrogen ligands similar to that of 4. Complex 5 reacts with 1 equiv of [K{N(SiMe3)(2)}] at room temperature to give [Ti-3(eta(5)-C5Me5)(3)(mu(3)-N)(mu-N)(mu-NH)(mu-NHSiMe3)] (6), which at 85 degrees C rearranges to the trimethylsilylimido derivative [Ti-3(eta(5)-C5Me5)(3)(mu(3)-N)(mu-NH)(2)(mu-NHSiMe3)] (7). Treatment of 7 with [K{N(SiMe3)(2)}] affords the potassium derivative [K{(mu(3)-N)(mu(3)-NH)(mu(3)-NiSMe3)Ti-3(eta(C5Me5)-C-5)(3)(mu(3)-N)}] (8), which upon addition of 18-crown-6 leads to the ion pair [K(18-crown-6)] [Ti-3(eta(5)-C5Me5)(3)(mu(3)-N)(mu-NH)(mu-NHSiMe3)] (9). The X-ray crystal structures of2, 5, 6, and 8 have been determined.Ministerio de Ciencia e Innovación de España, Comunidad de Madrid, Universidad de Alcalá, Ministerio de Educación y Ciencia de Españ

Electrophilic attack on trinuclear titanium imido-nitrido systems

Alkylation of [{Ti(eta(5)-C5Me5)(mu-NH)}(3)(mu(3)-N)] with MeOTf occurs at the imido ligands to produce the methylamido derivative [Ti-3(eta(5)-C5Me5)(3)(mu(3)-N)(mu-NH)(2)(mu-NHMe)(OTf)] which readily rearranges to form the methylimido complex [Ti-3(eta(5)-C5Me5)(3)(mu(3)-N)(mu-NH)(mu-NH2)(mu-NMe)(OTf)].Ministerio de Educación y Ciencia de España, Comunidad de Madrid, Universidad de Alcal