Pert using Fuzzy variables and probability distribution function randomly selected

Program Evaluation and Review Technique (PERT) is widely used for project management in real world applications. The aim of this paper is to simulate and analyze a PERT network under conditions of uncertainty though a hybrid model. The basic assumption is that a project under extreme conditions of uncertainty can be satisfactorily modelled by using simple fuzzy linguistic variables to estimate activities durations, and a probability distribution function randomly selected in order to measure the activity times. Fuzzy linguistic expressions are used to estimate the activity time. Activity parameters are calculated by using basic operations between triangular fuzzy numbers and centroid method with classical Beta PERT definition. For each activity time a probability distribution function is randomly selected from a set of four possible distributions commonly cited in the literature. Hypothetical projects with 4, 40, 400 and 4000 activities using the proposed model are analyzed; the project duration is estimated through Monte Carlo Simulation. Finally, results are analyzed and compared with classical Beta PERT technique

The Gamma-ray Albedo of the Moon

We use the GEANT4 Monte Carlo framework to calculate the gamma-ray albedo of the Moon due to interactions of cosmic ray (CR) nuclei with moon rock. Our calculation of the albedo spectrum agrees with the EGRET data. We show that the spectrum of gamma rays from the Moon is very steep with an effective cutoff around 3-4 GeV (600 MeV for the inner part of the Moon disk) and exhibits a narrow pion-decay line at 67.5 MeV, perhaps unique in astrophysics. Apart from other astrophysical sources, the albedo spectrum of the Moon is well understood, including its absolute normalisation; this makes it a useful "standard candle" for gamma-ray telescopes. The steep albedo spectrum also provides a unique opportunity for energy calibration of gamma-ray telescopes, such as the forthcoming Gamma Ray Large Area Space Telescope (GLAST). Since the albedo flux depends on the incident CR spectrum which changes over the solar cycle, it is possible to monitor the CR spectrum using the albedo gamma-ray flux. Simultaneous measurements of CR proton and helium spectra by the Payload for Antimatter-Matter Exploration and Light-nuclei Astrophysics (PAMELA), and observations of the albedo gamma rays by the GLAST Large Area Telescope (LAT), can be used to test the model predictions and will enable the LAT to monitor the CR spectrum near the Earth beyond the lifetime of the PAMELA.Comment: 6 pages, 4 figures, emulateapj.cls; to appear in the Astrophysical Journa

Antral follicular count is a tool that may allow the selection of more precocious Bradford heifers at weaning

Although antral follicle count is a repeatable parameter across life that is positively associated with fertility, its use at weaning as a tool to discard less fertile heifers has not been extensively evaluated. The hypotheses of this work are: 1) maximum antral follicle count (MAFC) is repeatable between weaning and pre breeding evaluations, allowing selection of more fertile heifers at an early age, 2) heifers with high MAFC have growth and development parameters linked to an earlier puberty and pregnancy, 3) MAFC has a positive correlation with AMH concentrations, so that both could be used inter changeably. In this study, Hereford (n = 42 and n = 50) and Braford (n = 40 and n = 50) females were used in years 1 and 2; respectively, in a completely randomized experimental design. Heifers were examined for five to ten days at two different moments (post weaning and pre service), to determine MAFC. The concentrations of Anti müllerian hormone (AMH) were evaluated on the day of MAFC assessment. Growth and development parameters were evaluated post weaning and pre service. The repeatability of MAFC between post weaning and pre service evaluations was poor in three cases (Hereford Year 1 = 0.36 and 2 = 0.39 and Braford, Year 2 = 0.32) but it was high for Braford in Year 2 (0.72). The AMH repeatability between post weaning and pre service evaluations was high in one case (Braford Year 2 = 0.72) and moderate in the others (Year 1, Hereford = 0.50 and Braford = 0.52 and Year 2, Hereford = 0.50). In Year 2, Braford heifers with greater MAFC attained puberty at an earlier age (r2 = 0.129; P = 0.0196). Also, diminished MAFC corresponded with decreased growth and development, thus less Braford heifers with low MAFC were inseminated (2/16), compared to those with medium (12/17) and high MAFC (7/17; P \u3c 0.01). Moreover, Braford heifers with low AFC had less progesterone in the cycle post insemination but pregnancy rate was not affected. In Braford heifers in Year 2, there was a high correlation between MAFC and AMH concentrations (0.85 P \u3c 0.001). The results of these experiments indicate that post weaning MAFC and AMH concentrations may be applied to select those Braford heifers that attain puberty at an early age, but these tools are not useful in Hereford heifers

Acerca de la XVIII edición del libro de texto Medicina Interna Farreras/Rozman

La Editorial Elsevier, presentó en el año 2016 la edición decimoctava del libro de texto Medicina Interna, publicado bajo la dirección de C. Rozman y la subdirección de F. Cardellach, que se encuentra a consideración de los estudiantes de medicina de todas las edades desde el año 1929. Es un texto clásico para la formación en medicina interna, en grado, postgrado, así como también para la actualización médica continua del profesional que ya se encuentra ejerciendo la medicina asistencial. El libro está impecablemente impreso, presentado en dos elegantes volúmenes, con tres colores diferentes de tinta, incluido el uso de varios colores en las tablas, cuadros y además imágenes de alta calidad.Los autores del texto, que juntos suman más de 400, dan consistencia a la obra, al presentar por una parte una amplia visión de la medicina interna por tan variados autores y, por otra parte, al asegurar de esta manera una alta calidad científica de los diferentes capítulos

Desarrollo a orden estricto C-4 del Modelo Semirelativista LRESC para el cálculo de propiedades magnéticas moleculares

En el presente trabajo se abordó el estudio de una de las posibles limitaciones de un método propio que introduce correcciones de efectos relativistas en el cálculo y análisis de propiedades magnéticas. Se trata del modelo teórico expresado en 2-coinponentes, denominado Linear response elimination of smallcornponents (LRESC), que parte del formalismo perturbativo de RSPT en 4- componentes. Mediante transformaciones adecuadas se obtienen operadores de corrección relativista dentro de una serie de potencias en c-1. Corno punto inicial del trabajo se retornó el desarrollo de este modelo (Melo et al., 2003). En el mismo, se calcularon los términos diamagnéticos con correcciones a orden c-4 para el apantallamiento magnético nuclear; se consideró en dicho trabajo solo el primer término del desarrollo en serie de la inversa de la diferencia de energías. En este trabajo se incluyen todos los términos co1Tectivos de dicha inversa que contribuyen al desarrollo en serie al orden c-4. Se demuestra aquí que, a orden c-4, el primer término de dicha serie incluye todas las correcciones hasta este orden. Por otro lado se desarrolló un esquema de expansión de la serie que permite hallar los términos correctivos a todo orden en potencias de c-1

Seismic Stability Analysis of Inca Earthen Walls

In many places around the world there still exist statues, walls and columns which, despite being located in areas of high seismicity, are still standing and in good conditions after several hundred years. Although Peru is located on a zone of high seismicity, some preColumbian walls are still standing after having withstood many intense earthquakes. The remarkably stable dynamic response of these structures when rocking freely due to horizontal ground motions has been extensively studied [1] [2]. The aim of the project presented in this article is to evaluate the probability of seismic overturning of Inca monuments (XVth century CE) during future strong earthquakes. The Wiracocha temple walls located near Cusco and the Inca trail walls that cross the PUCP campus in Lima were selected for this study. Both earthen walls were modelled as free-standing rigid blocks which could rotate around the corners at their base. A set of synthetic ground acceleration signals were then generated according to the seismicity and ground conditions of both sites. The artificial ground acceleration records were scaled to the uniform hazard spectrum of Peru for return periods of 500, 1000 and 2500 years and different moment magnitudes [3][4]. The rocking time history response of each wall due to these ground motions was then numerically computed and plotted in order to assess the seismic risk due to overturning of these important earthen monuments. The main conclusion is that these walls will most probably remain standing for many more centuries

Promotores de la desigualdad

El rol de El Mercurio fue el de colaborar con la CIA impulsando acciones de prensa para derrocar al gobierno socialista de Allende, dar sustento simbólico y político al régimen de Pinochet y ocultar crímenes de lesa humanidad. En la actual democracia chilena, los medios heredados de la dictadura operan, más que como desestabilizadores de un sistema político en particular, como relacionistas públicos de un modelo desigual y discriminador.Facultad de Periodismo y Comunicación Socia

Microhabitat temperatures and prevalence of the pathogenic fungus batrachochytrium dendrobatidis in lowland amazonian frogs

Until recently, it was assumed that the pathogenic fungus Batrachochytrium dendrobatidis (Bd) was not widely distributed in warm ecosystems such as lowland tropical rainforests because high environmental temperatures limit its growth. However, several studies have documented Bd infection in lowland rainforest amphibians over the past decade. In addition, a recent study focusing on museum-stored specimens showed that Bd has been present in the lowland Amazon for more than 80 years. These findings lent support to the idea that some lowland rainforest habitats offer suitable environmental conditions for Bd growth, even though most lowland areas may contain suboptimal conditions limiting the pathogen spread and growth. Here, we surveyed four sites in southeast Peru to examine the prevalence and the intensity of infection of Bd in lowland Amazonian amphibians and to fill a gap between two areas where Bd has been present for more than a decade. In one of these “hotspots” of Bd infection, the upper slopes of Manu National Park, several species experienced population declines attributed to Bd epizootics over the past 15 years. We also examined the thermal profile of the main microhabitats used by lowland Amazonian frogs to infer whether these microhabitats offer suitable thermal conditions for Bd growth. We detected Bd in nine lowland frog species and variation in prevalence of infection across years. Our findings suggest that the temperatures in the leaf litter and understory vegetation of some habitats offer suitable conditions for Bd growth

Aspectos morfológicos de Dicheilonema rheae Owen 1843 en ñandúes (Rhea americana)

El objetivo del trabajo fue reportar aspectos morfológicos del nematodo Dicheilonema rheae Owen 1843, documentados por microscopía óptica y electrónica, constituyendo la primera cita en Argentina para este parásito. Los especímenes de D. rheae (n=37) fueron colectados de 4 ñandúes provenientes de la Provincia de Buenos Aires, tres de ellos silvestres y uno de criadero. Los helmintos fueron conservados en solución de Railliet & Henry, medidos y microfotografiados. Los parásitos revelaron marcado dimorfismo sexual: los machos (n=20) midieron 18,24±3,61 cm y las hembras (n=17) 66,24±16,40 cm. Los machos mostraron una extremidad posterior curvada ventralmente, con alas caudales bien desarrolladas y papilas alargadas con espículas desiguales. La vulva de las hembras estaba ubicada en la región esofágica. La abertura oral se encontró rodeada por espesamientos cuticulares. Debajo de la boca se encontraron cuatro pares de papilas circulares. Los huevos, de cáscara gruesa, se presentaron larvados.