An advanced symbolic analyzer for the automatic generation of analog circuit design equations

A tool for symbolic analysis of analog integrated circuits is presented featuring accurate simplification, pole/zero extraction, and tools for parametric AC circuit characterization. The program, called ASAP, uses signal flowgraph methods and has been written in C for portability. In its current version, ASAP is able to deal with the complexity levels arising in typical analog building blocks when described by device-level models. The ASAP inputs and outputs, the architecture, and the graphical interface are discussed

Tool for fast mismatch analysis of analog circuits

A tool is presented that evaluates statistical deviations in performance characteristics of analog circuits, starting from statistical deviations in the technological parameters of MOS transistors. Performance is demonstrated via the analysis of a Miller OTA in two different configurations and a linearized CMOS transconductor. The CPU time is reduced by a factor of 25 to 90 with respect to conventional Monte Carlo simulation, while maintaining similar accuracy in the computations

Los procesos en gestión de calidad: un ejemplo en un centro educativo

Los procesos de calidad se caracterizan por ser acciones con un principio y un final claros y determinados. La norma UNE_EN ISO 9000-2000 señala que proceso es “el conjunto de actividades mutuamente relacionadas o que interactúan, las cuales transforman elementos de entrada en resultados”. La Junta de Castilla y León (2004) entiende por proceso cualquier secuencia de acciones interrelacionadas entre sí que se ordenan para dar servicio al usuario o cliente y que contribuyen a crear valor añadido en la organización en la que se desarrollan. Realmente lo que ocurre es que no se conoce bien lo que pasa en el “intermedio”, es decir el núcleo de los procesos. En este artículo se presenta la conceptualización, el desarrollo y la puesta en práctica de un proceso para alcanzar la calidad y se propone un proceso concreto en orden a su planificación, actualización, revisión y evaluación. Aunque cada organización puede planificar e implementar los procesos de la forma que estime conveniente, la ejemplificación de los mismos pretende facilitar nuevos diseños procesuales, su priorización, su selección, y su puesta en práctica para llegar a la evaluación de los mismo

Global design of analog cells using statistical optimization techniques

We present a methodology for automated sizing of analog cells using statistical optimization in a simulation based approach. This methodology enables us to design complex analog cells from scratch within reasonable CPU time. Three different specification types are covered: strong constraints on the electrical performance of the cells, weak constraints on this performance, and design objectives. A mathematical cost function is proposed and a bunch of heuristics is given to increase accuracy and reduce CPU time to minimize the cost function. A technique is also presented to yield designs with reduced variability in the performance parameters, under random variations of the transistor technological parameters. Several CMOS analog cells with complexity levels up to 48 transistors are designed for illustration. Measurements from fabricated prototypes demonstrate the suitability of the proposed methodology

Reliability of a 13000-SHS photovoltaic rural electrification programme

In this paper, a reliability analysis of a photovoltaic rural electrification (PVRE) programme is proposed considering the failures in the 13 000 installed Solar Home System (SHS) devices occurring over a long operating period of 5 years. A previous arrangement of the database and a brief explanation of the reliability concepts will serve to introduce the failure distribution of every component, from which the SHS lifetime operating features will be described. An application example will show the usefulness of the obtained results in the forecasting of spare parts during the maintenance period. The conclusions of this study may be useful in the scientific design of PVRE programme maintenance structures, with the goal of shedding some light on the technical management mechanisms in decentralised rural electrification

Discrimination against diacylglycerol ethers in lipase-catalysed ethanolysis of shark liver oil

This is the author’s version of a work that was accepted for publication in Food Chemistry. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Food Chemistry, 136 (2013): 464–471. DOI: 10.1016/j.foodchem.2012.08.004Lipase-catalysed ethanolysis of squalene-free shark liver oil was investigated. The mentioned shark liver oil was comprised mainly of diacylglycerol ether and triacylglycerols. In order to test discrimination against diacylglycerol ether, up to 10 different lipases were compared. The ratio of oil to ethanol and lipase stability were also evaluated. Surprisingly, lipase from Pseudomonas stutzeri was the fastest biocatalyst among all assayed, although poor discrimination against diacylglycerol ether was observed. The best results in terms of selectivity and stability were obtained with immobilised lipase from Candida antarctica (Novozym 435). Ethanolysis reaction after 24 h in the presence of Novozym 435 produced total disappearance of triacylglycerol and a final reaction mixture comprised mainly of diacylglycerol ethers (10.6%), monoacylglycerol ethers (32.9%) and fatty acid ethyl esters (46.0%). In addition, when an excess of ethanol was used, diacylglycerol ethers completely disappeared after 15 h, giving a final product mainly composed of monoacylglycerol ethers (36.6%) and fatty acid ethyl esters (46.4%).This work was supported by Comunidad Autónoma de Madrid (ALIBIRD, Project No. S2009/AGR-1469) and Consolider-Ingenio FUN-C-FOOD (CSD2007-00063)

Heuristic Thinking and Credibility of Organic Advertising Claims: The Role of Knowledge and Motivations

[EN] Consumers are often overexposed to sustainability symbols and claims on food product packages and find it di_cult to accurately judge their meaning when making purchase decisions. Based on the heuristic-systematic model (HSM), this paper aims to identify cognitive mechanisms to reduce the heuristic credibility of organic advertising claims and to increase the motivation for searching for more reliable information when making product judgements. Particularly, we hypothesize that knowledge and defense and accuracy motivations a_ect organic claim credibility, which in turn is related to organic product judgement. Data collected from an experimental between-subject study with a sample of 412 Spanish undergraduates was analyzed using partial least squares. The results indicated that claim credibility was directly related to the attribution of organic properties to products, and was a_ected by defense motivation especially when appropriate knowledge was not available. Improving consumers’ knowledge reduced organic claim credibility and triggered a positive e_ect of accuracy motivation on credibility. The findings stress the importance of improving the regulation of ambitious advertising claims and developing specific educational campaigns to empower consumers and prevent biased purchase decisions of organic products.S

EXPRESIÓN DIFERENCIAL EN LIRIO AZTECA (Sprekelia formosissima (L) HERBERT, MEDIANTE MARCADORES BIOQUÍMICOS

Algunas isoenzimas intervienen en procesos específicos de interés para los genetistas, tal como la floración, desarrollo de las plantas, altura, resistencia a plagas y enfermedades entre otras. Por lo que es importante determinar si existe expresión diferencial en lirio azteca (Sprekelia formosissima (L) Herbert durante las fases vegetativa y reproductiva por medio de marcadores bioquímicos. Durante estas fases, se recolectó tejido procedente de las hojas, los tépalos, el gineceo, y los estambres, y se maceraron adicionando un amortiguador de extracción, y cuyos extractos líquidos totales se usaron para determinar patrones isoenzimáticos mediante electroforesis en geles de almidón (SGE). La actividad enzimática diferencial se evaluó utilizando once sistemas isoenzimáticos, de los cuales sólo se observaron nueve formas enzimáticas o patrones de bandeo isoenzimáticos (PBI), a saber: dos bandas con peroxidasa (POX; EC 1.11.1.7), tres bandas mediante fosfatasa acida (ACP; EC 13.1.3.2), una con fosfoglucosa isomerasa (PGI; EC 5.3.1.9), dos para fosfoglucomutasa (PGM; EC 2.7.5.1) y una para malato deshidrogenasa (MDH; EC 1.1.1.37), la cual mostró el mismo PBI en todas las etapas de desarrollo de la planta. Para el propósito de esta investigación únicamente se consideraron los patrones de bandeo isoenzimáticos diferentes.La agricultura, es una de las actividades económicas más añejas de la historia, le ha permitido al hombre satisfacer sus necesidades alimenticias mediante el cultivo de cereales, granos, legumbres, frutos, forrajes para la alimentación de ganado y la producción de especies ornamentales de corte y macetearía. La rama florícola es de gran importancia económica en México y diferentes partes del mundo debido a la generación de empleos e ingresos generados por la venta de flores en maceta y corte en las diferentes épocas pico del año; las más importantes en México son: día de San Valentín, día de la madre, del padre, muertos y celebración del día de la virgen de Guadalupe. Para satisfacer la demanda en estas fechas, se cultivan diferentes especies florícolas entre las que destacan rosa, lílis, áster, solidago, girasol, crisantemos, entre otras. Por otra parte, en México existen especies silvestres que tienen enorme potencial ornamental y amplia diversidad genética como el lirio azteca (Sprekelia formosissima (L) Herbert) que se ha utilizado desde tiempos prehispánicos por sus propiedades medicinales, alimenticias y por la belleza de sus flores rojas escarlata En algunos países europeos como España e Inglaterra, existen empresas que comercializan durante todo el año material vegetativo de la especie (Vázquez-García et al., 1998). Hasta la fecha, en México existen pocos trabajos de investigación en lirio azteca que citen avances en algún campo del conocimiento, principalmente en el mejoramiento genético y la biología molecular. Uno de los objetivos que tiene esta última, es saber cómo está organizada la información genética a través del estudio del ADN y los mecanismos de regulan la expresión de genes. Una de las herramientas empleadas es la electroforesis horizontal sobre geles de almidón y la tinción histoquímica de las proteínas, Las zonas activas de esta macromolécula con capacidad codificante, llamadas exones, estimulan la síntesis de enzimas específicas en las distintas etapas del desarrollo de un organismo. Estos productos génicos provienen de diferencias determinadas genéticamente en la secuencia de aminoácidos y no incluye modificaciones postraduccionales de la secuencia o estructura. (Scragg, 2000). En el presente trabajo, empleando la técnica de electroforesis sobre geles se logró identificar los diferentes patrones de bandeo en tejidos de S. formosissima colectados durante la fase vegetativa y reproductivaCONACy

Technocratic Attitudes in COVID-19 Times: Change and Preference Over Types of Experts

Western publics show a sizable support for experts’ involvement in political decision making, that is, technocratic attitudes. This article analyzes two key aspects of these attitudes: technocratic attitudes’ stability and the heterogeneity in the demand for experts depending on the context. We first analyze how technocratic attitudes have been affected by an external event, the COVID-19 pandemic, that has placed experts’ role at the forefront of the public debate; this allows us to analyze the stability or change in these attitudes. Second, given that the pandemic quickly evolved from being a public health issue to becoming a political issue combining economic and public health dimensions, we examine whether framing the COVID-19 pandemic exclusively as a public health problem or as including a prominent economic dimension as well affects the type of public officials who are preferred to lead the political management of the crisis (independent experts with diverse professional skills or party politicians belonging to different parties and with a specialization in different policy fields). We pursue these two research goals through a panel survey conducted in Spain at two different time points, one before and another during the pandemic, in which we measure technocratic attitudes using an exhaustive battery; and through a survey experiment combining a conjoint design and a framing experiment. Results show that, first, technocratic attitudes have significantly increased as a consequence of the coronavirus outbreak; second, people’s preference for experts prevails against any other experimental treatment such as party affiliation; and, finally, preferences for the type of experts vary depending on the problem to be solved. In this way, this paper significantly increases our knowledge of the factors that affect variation in public attitudes towards experts’ involvement in political decision-making.This research was supported by a grant from the Spanish Ministry of Economy, Industry and Competitiveness Program. Grant number: CSO2017-89847-P. Luis Ramiro benefited from a grant by the Fondation Maison des Sciences de l'Homme (France), Programme Directeurs d'Etudes Associés DEA 2020