916 research outputs found
Passive Portfolio Management by Indexing: A Performance Analysis of High, Medium and Low Capitalization Indices in Mexico
En una gestión pasiva de inversiones mediante indexación, el desempeño del portafolio dependerá en gran medida de la habilidad para elegir el mejor índice. En este trabajo, se estudia el desempeño de cuatro de los principales índices bursátiles en México con la intención de seleccionar el mejor de ellos para una estrategia de inversión pasiva. Para resolver esta pregunta, a partir de la razón de Sortino, se propone la sustitución del exceso de retorno promedio por una definición de probabilidad de acierto y el uso de la máxima desviación estándar sobre el retorno objetivo negativo. Las nuevas medidas de desempeño arrojan resultados diferentes a los resultados de la medida tradicional de Sortino, siendo el IPC large cap el mejor índice para una estrategia pasiva, en términos de su relación riesgo-rendimiento y objetivo de rentabilidadIn a passive investing strategy through indexation, the portfolio performance
will depend largely on the ability to choose the best index. In this paper, we
study the performance of four of the main stock indices in Mexico with the
intention of selecting the best one for a passive investing strategy. To solve
this question, departing from the
Sortino ratio
, a definition of probability of
success substitutes the average excess return over a target and the use of the
maximum standard deviation on the negative target return. The new per-
formance measure gives different results to those of the traditional Sortino
ratio, with the IPC large cap being the best index for a passive strategy, in
terms of risk-reward ratio and return target
Early hospital readmissions post‐kidney transplantation are associated with inferior clinical outcomes
Unplanned hospital readmissions are common early post‐kidney transplantation. We investigated the relationship between early hospital readmissions and clinical outcomes in a single‐center retrospective study that included all adult kidney transplant patients between 2004 and 2008 with follow‐up to December 2012. The early hospital readmissions within the first 30 d were numbered and the diagnosis ascertained. Patients were grouped as none, once, and twice or more readmissions. Predictors of early readmissions were assessed, and clinical outcomes and patient and death‐censored kidney survival were compared. Among 1064 patients, 203 (19.1%) patients had once and 83 (7.8%) patients had twice or more readmissions within 30 d. Surgical complications, infections, and acute kidney injuries/acute rejection were three most common diagnoses. The length of initial hospital stay and African American race were among the variables associated significantly with readmissions. Patients with early readmissions had lower baseline renal function (p < 0.01) and more early acute rejection (p < 0.01). During follow‐up, only frequent readmissions, twice or more, within 30 d were associated with increased risk of death ( AHR 1.75, p = 0.01) and death‐censored kidney failure ( AHR 2.20, p < 0.01). Frequent early hospital readmissions post‐transplantation identify patients at risk for poor long‐term outcomes, and more studies are needed to understand the mechanisms.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106830/1/ctr12347.pd
CHAN CHAN: LA CIUDADELA “RIVERO”
Por Resolución Ministerial Nº 260 de fecha 15 de abril del presente año, la Casa de la Cultura del Perú mediante su Área de Investigación y Conservación del Patrimonio Cultural, se hizo cargo de los trabajos arqueológicos de las Ruinas de Chan Chan, inaugurando su programa para el año en curso con las excavaciones en la ciudadela “Rivero” el 26 de mayo. Chan Chan, la ciudad arqueológica más grande del Perú, está ubicada al Oeste y a 4 km más o menos de Trujillo, en la margen derecha del Río Moche; la ciudad está orientada de Sur a Norte, ocupando un área que comprende 5 km de largo y 3 km de ancho; empero, en el pasado debió haber tenido mayor extensión hoy disminuido por la acción depredadora de los agricultores
Linear Estimation of Location and Scale Parameters Using Partial Maxima
Consider an i.i.d. sample X^*_1,X^*_2,...,X^*_n from a location-scale family,
and assume that the only available observations consist of the partial maxima
(or minima)sequence, X^*_{1:1},X^*_{2:2},...,X^*_{n:n}, where
X^*_{j:j}=max{X^*_1,...,X^*_j}. This kind of truncation appears in several
circumstances, including best performances in athletics events. In the case of
partial maxima, the form of the BLUEs (best linear unbiased estimators) is
quite similar to the form of the well-known Lloyd's (1952, Least-squares
estimation of location and scale parameters using order statistics, Biometrika,
vol. 39, pp. 88-95) BLUEs, based on (the sufficient sample of) order
statistics, but, in contrast to the classical case, their consistency is no
longer obvious. The present paper is mainly concerned with the scale parameter,
showing that the variance of the partial maxima BLUE is at most of order
O(1/log n), for a wide class of distributions.Comment: This article is devoted to the memory of my six-years-old, little
daughter, Dionyssia, who leaved us on August 25, 2010, at Cephalonia isl. (26
pages, to appear in Metrika
Temporal evolution of long-lived magmatic systems: the Chachani volcano complex, south of Perù
The Chachani Volcanic Complex (CVC) is an extensive (~289±10 km3) assemblage of spatially, temporally and genetically related major and minor eruptive centers. The c. 1.2 Myr-long activity suggests that the CVC is a long-lived volcanic system characterized by semi-persistent activity and short periods of quiescence. The stratigraphy, Ar/Ar and U/Pb chronology, spatial distribution along lineaments, and the degree of landform preservation help distinguish two groups of edifices in the CVC. The ‘old’ edifice group is characterized by large stratovolcanoes and small dome coulees. This group has been built between
In‐situ extraction and impregnation of black walnut husk into polyethylene film using supercritical carbon dioxide with an ethanol modifier
Walnuts are commonly cultivated for their kernel, which is a rich source of antioxidant phenolic compounds. The husk likewise contains antioxidant and antimicrobial compounds, but is typically discarded without further processing. Antioxidant compounds are useful in creating active packaging films, but typically decompose at melt extrusion temperatures in polymer processing. Due to carbon dioxide\u27s low critical point and ability to swell polymer films, supercritical carbon dioxide may be used to impregnate phenolic compounds into polymers. For this study, a novel technique is used to simultaneously produce walnut husk extracts and impregnate the extract into polymer films in the same batch extractor using supercritical carbon dioxide with a 15 wt-% ethanol modifier at 60°C at 19.4 MPa. The effect of varying the loading of walnut husk in the extractor upon impregnation mass was evaluated with the impregnation mass of the film increasing with walnut husk loading. It was determined by FTIR, as well as the eduction of the protein cytochrome c, that antioxidant compounds may be extracted from walnut husks and impregnated into low-density polyethylene film (LDPE) by this technique
Numerical simulation of strongly nonlinear and dispersive waves using a Green-Naghdi model
We investigate here the ability of a Green-Naghdi model to reproduce strongly
nonlinear and dispersive wave propagation. We test in particular the behavior
of the new hybrid finite-volume and finite-difference splitting approach
recently developed by the authors and collaborators on the challenging
benchmark of waves propagating over a submerged bar. Such a configuration
requires a model with very good dispersive properties, because of the
high-order harmonics generated by topography-induced nonlinear interactions. We
thus depart from the aforementioned work and choose to use a new Green-Naghdi
system with improved frequency dispersion characteristics. The absence of dry
areas also allows us to improve the treatment of the hyperbolic part of the
equations. This leads to very satisfying results for the demanding benchmarks
under consideration
Assessment of mesial temporal sclerosis through MRI processing
[EN] Mesial temporal sclerosis (MTS) is the principal cause of complex epilepsy, is manifested principally by gliosis and hippocampal volume loss. This project aims to develop an algorithm that allows automatic measurement of hippocampal volume and signal intensity in magnetic resonance imaging. The algorithm developed uses preprocessing of the images to reduce the artifacts and for the extraction of the features were used techniques of machine learning (support vector machine) and texture analysis. Results can help to optimize time in the assessment of the mesial temporal sclerosis and can contribute to the best training to the youngers neuroradiologists.Castillo-Malla, DP.; Samaniego, R.; Jimenez-Gaona, Y.; Sánchez, A.; Carrión, J.; Rodríguez-Álvarez, MJ. (2020). Assessment of mesial temporal sclerosis through MRI processing. Proceedings of SPIE (Online). 1-7. https://doi.org/10.1117/12.2569043S1
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