Algebraic symmetries of generic (m+1)(m+1) dimensional periodic Costas arrays

In this work we present two generators for the group of symmetries of the generic $(m+1)$ dimensional periodic Costas arrays over elementary abelian $(\mathbb{Z}_p)^m$ groups: one that is defined by multiplication on $m$ dimensions and the other by shear (addition) on $m$ dimensions. Through exhaustive search we observe that these two generators characterize the group of symmetries for the examples we were able to compute. Following the results, we conjecture that these generators characterize the group of symmetries of the generic $(m+1)$ dimensional periodic Costas arrays over elementary abelian $(\mathbb{Z}_p)^m$ groups

Rethinking the development of social policy in front of the millennium goals. changing programs and speeches as alternatives to the official message

This article focuses on Mexicans, socially perceived as poor, and the impact of social policy in force in the second decade of the 21st century, focused on improving the living conditions of the population, living in poverty and facing the national democratic process, which represents the alternative of change to the national conditions in Mexico. A country with social inequalities, where the lack of guaranteeing equal living conditions through institutional frameworks that guarantee opportunities and access to common satisfiers is evident. Therefore, in the midst of a democratization process, the State seeks to address the levels of precariousness. In the midst of the recognition of the basic needs to be met among those who are reviewing the renewed social policy of the 21st century, the need to strengthen the living conditions of the excluded is prioritized and in its consolidation process it would guarantee attention to poverty through institutional channels. This is the case of the social development law, which deals with a problem of productive order from a State vision. An analysis is carried out that seeks to identify the relationship between the effectiveness of current actions to combat the lack of attention to basic needs and the institutionalized discourse, which, according to the social research approach, strengthens the interest in conducting studies on social precariousness as a group characteristic; fueled by the political discourse, exalted by the government in turn of the poor first. In this case, it is the message that strengthens the need to analyze the way, in which poverty is measured based on the recognition of poverty lines, as an instrument that allows knowing the number of people in that condition, according to the levels of dissatisfaction of food needs and due to the low level of economic income (inability to consume a basic set of food goods) for rural and urban environments. Therefore, it seeks to measure the lack of food needs, without considering the causes of inability to generate minimum income levels to consume basic foods

Interactions between inflation, monetary and fiscal policy.

In Chapter 1 I develop a simple model, that builds upon some previous work on financial innovation processes, to account for the main stylized facts observed during extreme hyperinflations. The modeling device used here helps to reconcile some conflicting views on the causes, development and end of a hyperinflation without departing from the rational expectations assumption. Specifically, it is shown that the effectiveness of a future orthodox reform to preclude the occurrence of a hyperinflation, either speculative or fundamental, is an endogenous outcome which depends on a wide array of policy choices (fiscal and monetary) and structural features of the economy. In Chapter 2 I examine the postulates of the Fiscal Theory of the Price Level (FTPL) under an interest rate peg. I show that the usual definition of a non-Ricardian plan involves a non-credible government policy commitment, thus confuting the interpretation of the FTPL as a policy-based equilibrium selection device. Then I identify the set of necessary conditions for the implementation of non-Ricardian fiscal plans that result in a unique equilibrium. A critical necessary condition for the credibility of a fiscalist plan is that the equilibrium level of seigniorage must be non-positive. I argue that the fiscalist stock-analogy is only meaningful, precisely, when money enters into the government constraint as a destination of funds, rather than as a source. In Chapter 3, I extend Buiter's (2001, 2002) criticism (non-Ricardian plans are generally non-implementable whenever the monetary authority sets a non-contingent sequence of money supplies) to an infinite horizon economy. In particular, it is shown that a fiscalist deflation involves the violation of a household's optimality condition and that the notion of a fiscally-induced speculative hyperinflation cannot be rationalized invoking a symmetry between the problem of pricing a potentially fiat non-convertible asset (like money) and that of pricing the stock of a private firm as advocated by the FTPL

Producción de extractos enzimáticos a partir de Fomes sp. EUM1 y su evaluación en condiciones ruminales

En este estudio se evaluó la capacidad del hongo termotolerante Fomes sp. EUM1 para crecer en cultivo superficial utilizando 13 diferentes subproductos agrícolas. Se encontró que es capaz de crecer y producir enzimas lignocelulolíticas en un intervalo de pH de 4.5 a 7.4. A los 7 días de cultivo en cajas Petri se obtuvo el extracto crudo enzimático y se determinó la producción enzimática. De los subproductos evaluados, el rastrojo de maíz promovió la mayor producción de celulasas y lacasas siendo de 18.3 y 0.9 UI mL¯¹ , respectivamente. La mayor producción de xilanasas fue en la paja de cebada (26 UI mL¯¹ ), sin embargo, la producción de lacasas fue la más baja (0.4 UI mL¯¹ ) además presentó el menor diámetro de crecimiento (P˂0.05). A partir de lo anterior, se determinó la producción de enzimas lignocelulolíticas por el hongo termotolerante Fomes sp. EUM1 en cultivos sólidos usando como sustrato únicamente rastrojo de maíz (Rm), así como suplementado con 20% de salvado de trigo (Rm:St). Esta suplementación aumentó (P˂0,05) la producción de xilanasas (160 UI g ms¯¹), a los 5 días de cultivo. Las celulasas no mostraron diferencias en la producción al quinto día de cultivo, para Rm y Rm:St, 33 y 37 UI g ms¯¹, respectivamente: sin embargo, el agregar salvado de trigo originó una disminución menor en la actividad, al día 6. La actividad de lacasas alcanzó una producción de 3 UI gms¯¹ al utilizar el Rm:St, manteniendo este nivel de producción hasta al día 7 de cultivo. Por otra parte; los ensayos de estabilidad (39 ⁰C y pH 6), medida como tiempo de vida media (t ½), de los extractos crudos enzimáticos para estas tres enzimas evaluadas, mostraron que el t ½ para las celulasas y xilanasas no mostraron diferencias significativas (P˃0.05) para ambos sustratos; mientras que para las lacasas se observaron diferentes patrones de t ½, alcanzando a duplicarse para el Ext Rm:St (26.6 h). Ambos extractos de Fomes sp. EUM1 y un producto enzimático comercial (Fibrozyme®)se utilizaron en diferentes forrajes como el rastrojo de maíz, bagazo de caña y heno de alfalfa, para medir la digestibilidad y producción de gas in vitro. La tasa fraccional de producción de gas (FR; mL g-1 h -1 ) aumentó (P˂0.05) a las 9 h en rastrojo de maíz comparada con el tratamiento sin enzimas. El uso de enzimas siempre favoreció un mayor volumen de gas máximo (Vm, h¯¹) en el bagazo de caña. La digestibilidad in vitro (DIV) del rastrojo de maíz aumento (12%) con respecto al control, al usar el producto comercial, mientras que los extractos enzimáticos originados por Fomes sp. EUM1, en rastrojo de maíz y rastrojo de maíz con salvado de trigo mostraron un incremento en la digestibilidad del 16 y 21 % (P˂0.05), respectivamente, lo que sugiere una mayor especificidad de estas enzimas producidas en el mismo sustrato (Rm). Además de la estabilidad probada, la versatilidad de los extractos de Rm y Rm:St fue confirmada por el aumento en los valores de digestibilidad in vitro para bagazo de caña (hasta 100%) en relación con el testigo sin enzimas. De los resultados obtenidos en las pruebas in vitro, se evaluó el efecto del extracto crudo enzimático (Ext Rm:St) producido mediante fermentación en estado sólido por el hongo Fomes sp. EUM1, en la digestibilidad y comportamiento productivo de corderos, alimentados con una dieta forraje:concentrado de 60:40. El hongo se cultivó (6 d) y se midió la actividad enzimática alcanzada, siendo de 169 UI g ms -1 , 50 UI g ms -1 y 4 UI g ms-1 , para xilanasas, celulasas y lacasas, respectivamente. Para la prueba in vivo se utilizaron 18 corderos Suffolk x criollos con un peso inicial (PI) de 20 kg ± 0.5 por 58 días. Los tratamientos consistieron en tres dosis del Ext Rm:St por kg de materia seca de rastrojo de maíz 0, 60 y 120 mL, asperjado al forraje 24 h antes de ser proporcionado. Los corderos se pesaron cada 14 días. En el día 58 se tomaron muestras de líquido ruminal para determinar ácidos grasos volátiles (AGV) y la actividad enzimática. No se encontraron diferencias (P>0.05) entre tratamientos por efecto de la dosis enzimática en el consumo de MS, MO, FDN y FDA. Por otra parte, la ganancia diaria de peso presentó un efecto lineal (P˂0.08) positivo al uso del Ext Rm:St. La digestibilidad de la MS, FDN y FDA presentaron incrementó con la dosis media de extracto enzimático (efecto cuadrático, P˂0.05). La proporción de ácido butírico también se incrementó con la dosis de 120 mL kg-1 MS (efecto cuadrático, P˂0.05). La actividad de celulasas en el líquido ruminal presentó un incremento lineal (P˂0.05) en función de la dosis de extracto. El Ext Rm:St del basidiomiceto termotolerante Fomes sp. EUM1 favorecieron la actividad celulolítica en el líquido ruminal, manifestándose una mayor ganancia de peso en los corderos a mayor dosis de enzima. Con los resultados anteriores se muestra que los extractos enzimáticos obtenidos de Fomes sp. EUM1 son una alternativa para su uso sobre residuos lignocelulósicos, enfocándose al tratamiento previo de los forrajes para su inclusión a la dieta. El aporte de enzimas fibrolíticas lo mantienen como alternativa para su uso en la alimentación animal, debido a que posiblemente aumente los sitios de unión a las fibras por parte de las bacterias ruminales.This study evaluated the ability of Fomes sp. EUM1, a previously identified thermotolerant fungal strain, to grow in superficial culture media, in Petri dishes, using 13 different agricultural by-products. The strain produced lignocellulolytic enzymes in a range of pH from 4.5 to 7.4. From the substrates tested, corn stover promoted the highest production of cellulases and laccases with an activity of 18.3 and 0.9 IU mL ̄¹, respectively. The maximal xylanase production was in barley straw (26 IU ml⁻¹ ), however, the laccase production was the lowest (0.4 IU ml⁻¹ ), in addition to the lowest growth with diameter 5.5 cm after 7 days (P˂0.05). These results suggested that lignocelullolytic enzymes can be produced by the thermotolerant fungus Fomes sp. EUM1 in solid substrates using corn stover substrate only (Rm) and supplemented with 20% wheat bran (Rm:St). The supplementation increased (P˂0.05) the xylanase production (160 IU g ms-1 ) after 5 days of culture. Cellulases showed no difference in the production on the fifth day of culture, for Rm and Rm: St, 33 and 37 IU g ms-1 , respectively; however the addition of wheat bran caused a decrease in activity on day 6. Laccase activity reached a production of 3 IU g ms-1 with the Rm: St, maintaining this level of production until day 7 of culture. Moreover, the stability tests at 39 °C and pH 6, measured as half-life (t ½) of the crude enzyme extracts for these three enzymes showed that those t ½for cellulases and xylanases did not showed significant differences (P˂0.05) for both substrates, while for laccases different patterns were observed for t ½, in fact this value was doubled in extracts from Rm Ext: St (26.6 h). Both extracts from Fomes sp. EUM1 and a commercial enzyme product (Fibrozyme®) were used in different forages as corn stover, bagasse and alfalfa hay to measure ruminal digestibility and gas production in vitro. The fractional rate of gas production (FR; mL g-1 h -1 ) increased (P˂0.05) at 9 h in corn stover compared with treatment without enzymes. The use of enzymes always favored a higher maximum gas volume (Vm, h-1 ) in the bagasse. The in vitro digestibility (IVD) of corn stover increased (12%) compared to the control, using the commercial product; whereas the enzymatic extracts obtained by Fomes sp. EUM1 in corn stover and corn stoverwheat bran showed an increase in the digestibility of 16 and 21% (P˂0.05), respectively, suggesting a higher specificity of these enzymes produced on the same substrate (Rm). Besides proven stability, versatility extracts Rm and Rm:St was confirmed by the increase in the in vitro digestibility values for bagasse (100%) compared to the untreated enzymes. From the results obtained in these in vitro tests, effects of the crude enzyme extract (Ext Rm:St) produced by solid state fermentation were evaluated using animals in vivo, measuring both digestibility and productive performance of lambs fed a forage: concentrate 60:40. The fungus was grown (6 d) and enzyme activity was measured being 169 IU g ms-1 , 50 IU g ms-1 and 4 IU g ms-1 for xylanases, cellulases and laccases, respectively. For these experiments during for 58 days,18 Criollos x Suffolk lambs were used, weighing initial (PI) of 20 ± 0.5 kg. Treatments consisted of three doses of Rm Ext: St per kg of dry corn stover: 0, 60 and 120 mL, which were sprayed to the fodder 24 h before being provided. The lambs were weighed every 14 days. On day 58 samples were taken to determine rumen fluid volatile fatty acids (VFA) and enzymatic activity. No differences (P>0.05) among treatments for enzymatic dose effect on consumption of DM, OM, NDF and ADF. Moreover, lambs the average daily gain showed a linear effect (P˂0.08) positive use Ext Rm: St. The digestibility of DM, NDF and ADF increased with the average dose of enzyme extract (quadratic effect, P˂0.05). The cellulase activity in the rumen fluid showed a linear increase (P˂0.05) depending on the dose of extract. With the above results show that the enzymatic extracts obtained from Fomes sp. EUM1 are an alternative for use on lignocellulosic residues, focusing the pretreatment of fodder for inclusion to the diet. The contribution of fibrolytic enzymes alternatively kept for use in animal feed because it may increase the binding sites to the fibers by ruminal bacteria

Long-chain bases, phosphatidic acid, MAPKs, and reactive oxygen species as nodal signal transducers in stress responses in Arabidopsis

Due to their sessile condition, plants have developed sensitive, fast and successful ways to contend to environmental changes. These mechanisms operate as informational wires conforming extensive and intricate networks that are connected in several points. The responses are designed as pathways orchestrated by molecules that are transducers of protein and non-protein nature. Their chemical nature imposes selective features such as specificity, formation rate and generation site to the informational routes. Enzymes such as mitogen-activated protein kinases (MAPK) and non-protein, smaller molecules, such as long chain bases, phosphatidic acid and reactive oxygen species are recurrent transducers in the pleiotropic responses to biotic and abiotic stresses in plants. In this review, we considered these four components as nodal points of converging signaling pathways that start from very different stimuli and evoke very different responses. These pleiotropic effects may be explained by the possibility that every one of these four mediators can be expressed from different sources, cellular location, temporality or magnitude. Here, we review recent advances in our understanding of the interplay of these four specific signaling components in Arabidopsis cells, with an emphasis on drought, cold and pathogen stresses

Bank lending policies and monetary policy: some lessons from the negative interest era

What is the long-term impact of negative interest rates on bank lending? To answer this question, we construct a unique summary measure of negative rate exposure by individual banks based on exclusive survey data and banks’ balance sheets and couple it with the credit register of Spain and firms’ balance sheets to identify this impact on the supply of credit to firms. We find that only when deposit rates reached the zero lower bound did affected banks (relative to non-affected banks) decrease their supply, especially when undercapitalized and lending to risky firms. The adverse effects of the negative rates on banks’ intermediation capacity only took place after a protracted period of time

Análisis de un sistema de ventilación.

Proyecto de Graduación (Bachillerato en Ingeniería en Mantenimiento Industrial) Instituto Tecnológico de Costa Rica. Escuela de Ingeniería Electromecánica, 2003.El proyecto administrativo propone un programa de mantenimiento preventivo y la creación de los principales documentos del departamento de mantenimiento en base a las especificaciones de ISO 9000 versión dos mil. Para su realización se sigue una serie de pasos fundamentados en el análisis de la situación actual, en la recolección de datos y por medio de accesorias referidas hacia implementación de la norma ISO 9000 dentro de la empresa. Se tiene como objetivos: realizar los registros necesarios para darle seguimiento a todas las labores de mantenimiento que se presenten o desarrollen durante diferentes periodos de tiempo, por otra parte se pretende también fomentar una actitud preventiva en el personal de la planta y controlar las labores realizadas a la infraestructura por medio de las ordenes de trabajo. Con lo que se asegure el éxito en el programa de mantenimiento preventivo

Análisis de los factores sociales, económicos y políticos que influyen en la inserción de los jóvenes egresados de la Unan-Managua RURD al mercado laboral formal. 2013-2014

Las asimetrías económicas que prevalecen dentro del modelo centro-periferia (Prebish, 1950) en la actual coyuntura del comercio mundial, establecen un nivel de inequidad, fomentan una mayor brecha de lo que representa el desarrollo y subdesarrollo entre los países. La hegemonía del norte sobre el sur, la gran capacidad adquisitiva de los países ricos y su elevado nivel de libertades y oportunidades (Berlin, 1909-1997) contrastantes con el inferior nivel del que disponen los Estados en vías de desarrollo, limitados en su capacidad para proyectar en su población los beneficios que emana la libre agencia individual (Sen, 2000), indispensable para constituir una base poblacional altamente competitiva y calificada, que propicie un alto nivel de desarrollo económico y social para la nación, cimenta las bases sobre las cuales, países como el nuestro [Nicaragua], sobrelleva una grave crisis económica y un alto nivel de dependencia en relación con las grandes potencias, por lo tanto, esto limita su capacidad de desarrollo social y económico, y propicia un gran nivel de subordinaciones económicas y políticas generadas por la cooperación económica internacional. Factores como la salud y educación bajo el actual contexto de asimetría económica internacional, resultan grandemente afectados en cuanto su efectividad y capacidad para cubrir a la población más desprotegida, lo que limita a la población a disponer de un nivel óptimo de preparación física y profesional, vital para impulsar un nivel de desarrollo social sostenible, que permita al Estado aprovechar el factor humano

Nivel de resiliencia y estrés académico en estudiantes de la carrera de Psicología de una universidad privada en el contexto de la COVID-19

El objetivo general fue determinar cuál es la relación que existe entre nivel de resiliencia y el estrés académico en estudiantes de la carrera de Psicología de una Universidad Privada en el contexto de la COVID-19. Se utilizó un enfoque de investigación cuantitativa, de alcance correlacional y de diseño no experimental transversal. La técnica que se utilizó es la encuesta y los instrumentos son la Escala de Resiliencia (ER) de Wagnild y Young (1993) y el Inventario SISCO de estrés académico de Barraza (2007). La población estuvo conformada por 539 estudiantes de VIII a X ciclo y la muestra fue de 115 estudiantes. La conclusión principal fue que existe una correlación negativa moderada entre el nivel de resiliencia y el nivel de estrés académico (r=-0.533)

Framework to estimate the benefit-cost ratio of pavement skid improvements at the network level

Research has proven that low values of pavement skid increase crash risk. Minimum skid thresholds have been established in order to screen projects for further testing and improvements. Skid resistance values are used in addition to crash data, pavement condition data, and roadway features to select and prioritize skid improvement projects. Furthermore, skid resistance performance models have been developed in order to capture the skid deterioration over time. However, the aforementioned studies did not quantify the economic impact of skid improvements over a time period for a network. This thesis fills this information gap, by providing a framework that quantifies the Benefit-Cost Ratio (BCR) of skid resistance improvements at the network level. A skid deterioration model is developed using the Markov Chain process, in order to account for the base case scenario when no treatment is applied. Benefits are quantified as the reduction of expected crashes compared to the base case scenario, using the concept of Crash Rate Ratio (CRR). Costs are quantified as the costs of pavement resurface treatments that improve skid. A sample of highway sections that comprise 564 lane-miles in Texas is evaluated to demonstrate the applicability of the proposed methodology. As a result, a Benefit-Cost Ratio curve was generated for different minimum skid thresholds.Civil, Architectural, and Environmental Engineerin