Ductilidad del acero inoxidable bajo en níquel para estructuras de hormigón armado / Ductility in a new low nickel stainless steel for reinforced concrete

En este trabajo se presentan los diagramas tensióndeformación de un nuevo acero inoxidable con bajo contenido en níquel, un inoxidable convencional AISI 304 y un acero al carbono de uso común en estructuras de hormigón armado. Dicha ductilidad se ha estudiado determinando la tensión máxima (fmax), la tensión en el límite elástico (fy) y la deformación bajo carga máxima (εmax). Los tres materiales se han evaluado utilizando criterios aceptados internacionalmente, como son el índice p (capacidad de rotación plástica), el índice A* (área plástica de endurecimiento) y el índice de tenacidad Id (energía total absorbida en el punto de alargamiento bajo carga máxima), los resultados obtenidos se han comparado con los aceros convencionales de armaduras 500SD, 500N y 500H (EC-2)

Caracter?sticas de la comprensi?n de los enunciados en la resoluci?n de problemas para la sustracci?n de tipo comparaci?n

105 p. Recurso Electr?nicoEn este estudio se examina las caracter?sticas de la comprensi?n de los enunciados en la resoluci?n de problemas para la sustracci?n de tipo comparaci?n, en estudiantes de grado 4?, por medio de unos cuestionarios realizados a 38 estudiantes de una instituci?n educativa oficial en la ciudad de Ibagu?. Con esto se pretende organizar la informaci?n de manera descriptiva apoyado por autores c?lebres en la educaci?n matem?tica como lo es Maza (1991), Luce?o (1999), Puig y Cerdan (1988) entre otros; que brindan insumos para la estructuraci?n de procesos fundamentales en la comprensi?n de enunciados. Las categor?as formadas desde las respuestas de los ni?os, tales como comprensi?n lectora, comprensi?n matem?tica, formulaci?n de m?todos de soluci?n y otras (est?n orientadas por el marco te?rico), que son fundamentales para un entendimiento m?s claro y practico en los ni?os, deben ser analizadas de manera detallada para poder generar una verdadera comprensi?n en los enunciados. Con respecto a los problemas, arrojan resultados heterog?neos; considerando que, para la comprensi?n adecuada, los estudiantes deben encontrarse en los mayores niveles de cada categor?a al cursar el grado 4?, es decir, se encuentra dificultades en cada una de las categor?as establecidas en este documento. Palabras clave: resoluci?n de problemas, comprensi?n, categor?as, estructura, comparar.In this research the characteristics of the mathematical formulations understanding in problem-solving for comparison-type subtraction are examined in 38 fourth graders of an official educative Institution in Ibague through some questionnaires. This is intended to organize the information in a descriptive manner, supported by mathematics education famous authors as Maza (1991), Luce?o(1999), Puig and Cerdan (1988), among others; who provide input for fundamental processes structuration in mathematical formulations understanding. The categories formed from students? answers, as reading comprehension, mathematics comprehension, formulation of settlement methods, and other (they are oriented by the theoretical framework) are essential for a clearer and more practical understanding among children and should be analyzed in detail to generate genuine comprehension of the mathematical formulations. Regarding problems, they show mixed results; considering that, for a proper comprehension, students must be at the highest levels of each category when studying 4th grade, namely, they are found difficulties in each of the categories established in this document. Keywords: problem-solving, comprehension, categories, structure, to compare

Evaluating the yield of surviving plants from early-season hail damage in corn: A field survey

Economic losses due to hailstorms acrossUS corn fields occur every year.Hailstorms result in leaf defoliation, decreasing photosynthetic area and impairing carbon assimilation and crop yield for all corn (Zea mays L.) development stages. However, more attention is often given to stand reductions rather than damage to stems or leaf defoliation. During the 2014 growing season, a natural hail event affected many areas of eastern Nebraska. Twelve affected corn fields were surveyed and included in this study. An injury score scale (1–5) was developed based on various injury and severity levels before the V6 (6-leaf corn growth stage) (six-collared leaves). Scores were assigned to affected fields approximately 10–15 days after the hailstorm. At the end of the growing season, ears were harvested, and grain yield per plant was determined. The highest grain yield (p \u3c 0.05) was recorded with plants that were affected but retained a main stem in good condition, albeit defoliation was present (score 1, lowest damage category). In contrast, when the main stem was cut and the plant had poor regrowth (score 3), yields were reduced by approximately 53% compared to plants with an injury score of 1. A significant negative linear relationship (R2 = 0.63, p \u3c 0.01) between injury score and yield was observed (higher injury score from hail events resulted in lower yields). Based on these results, corn yield reduction due to plant injury from hail events before V6 should not be only attributed to stand reductions. Our findings indicate an opportunity to adjust the US evaluation standards for early-season hail damage events in corn fields

Estudio del impacto que tienen en el medio sociocultural los graduados del programa licenciatura en educaci?n b?sica con ?nfasis en la lengua castellamna del instituto de educaci?n a distancia - IDEAD- de la Universidad del Tolima.

74 p. Recurso Electr?nicoEl estudio del impacto que tienen en el medio sociocultural los graduados del programa Licenciatura en Educaci?n B?sica con ?nfasis en Lengua Castellana, se realiz? mediante un seguimiento que nos permiti? identificar como primera medida el efecto que tienen en su contexto. De igual manera, reconocer cuales son las principales razones por las que optaron como medio de profesionalizaci?n la Modalidad a Distancia y los reconocimientos acad?micos o econ?micos que han recibido en el transcurso de su formaci?n y el desarrollo de su labor docente. Este trabajo se realiz? por medio de la elaboraci?n de una encuesta, la cual se aplic? a una base de datos de aproximadamente 1200 graduados de los centros tutoriales Ibagu?, Bogot?, Cali, Pereira, Neiva, Tunal, Kennedy, Sibat?, Icononzo y Girardot donde ha sido ofertado el programa, logrando contactar 637 Licenciados que en su gran mayor?a actualmente se encuentran laborando como docentes en las diferentes Instituciones Educativas a nivel departamental y nacional, los cuales en sus diferentes contextos han sido reconocidos por su labor acad?mica y su desempe?o profesional. Como resultado de esta encuesta, se pudo identificar que las razones m?s relevantes para escoger la Educaci?n a Distancia como medio de formaci?n profesional es principalmente la facilidad de trabajar y estudiar a la vez, seguido de la flexibilidad de los horarios, sin dejar a un lado el factor econ?mico y la posibilidad que se ofrece a los padres y madres cabezas de hogar. Por tal raz?n, hemos concluido que el programa Licenciatura en Educaci?n B?sica con ?nfasis en Lengua Castellana que es ofrecido por el Instituto de Educaci?n a Distancia (IDEAD) de la Universidad del Tolima, merece ser calificado como un programa de alta calidad ya que cumple con los requisitos requeridos por el CNA (Consejo Nacional de Acreditaci?n) y adicionalmente es pertinente e impactante en la formaci?n integral de licenciados y de los futuros l?deres en los contextos educativos.The study of the impact that have graduates in the socio-cultural field from Bachelor's Degree in Basic Education with Emphasis in Spanish Language program, it was developed through the tracing, which allows us to identify as a first action the effect on their context. As well as, recognize which are the main reasons to have been chosen as a professionalization medium the distance modality, and the academic or economical acknowledgments that have been received during their education and the development of their teaching work. This work was developed through by making an inquiry, which was applied on a data base with 1200 graduates approximately from the tutorial centers Ibagu?, Bogot?, Cali, Pereira, Neiva, Tunal, Kennedy, Sibat?, Icononzo and Girardot where it has been offered the program, achieving contact 637 licensed which most of them nowadays are working as teachers in the different educational institutions at the departmental and national level, which in their different contexts have been recognized by the academic labor and professional performance. As a result of this inquiry, it was possible to identify the most relevant reasons to choose the distance education as a medium of professional training it is mainly the ease to work and study at the same time, then, the schedules flexibility, without forget the economical factor and the opportunity that offers for parent?s head of household. For this reason, we have concluded that the Bachelor's Degree in Basic Education with Emphasis in Spanish Language program offered by the Institute of distance education (IDEAD) from University of Tolima, deserves to be qualified as a high-quality program, because it accomplishes with the standards required by the CAN (National Accreditation Board), additionally it is essential and shocking in the integral education of licensed and the future leaders in the educational contexts. Keywords: Accreditation, Impact, Distance Modality, Education

Leucaena leucocephala cv Perú in Association with Graminaceae in Dryland Conditions for Final Bovine Fattening Stage

To evaluate the factors that affect efficiency in a Leucaena leucocephala cv Perú association, with pastures for bovine fattening, 22 Zebu fattening cycles were studied on a farm of the Rectangulo Livestock Company, in Camagüey, Cuba, between 2002 and 2012. The local soil is brown without carbonates. The climate is tropical humid, and the annual precipitation average is 1 183mm. The factors evaluated were food balance, duration of the fattening cycle, and quantity of animals/cycle. The daily weight gain and expenses/income per operation were also analyzed. The pasture and Leucaena percentages were determined by plant counts. Food balances were estimated. The final value of the population of Leucaena cv Perú was 93% (P <0.05), with an increase in common Bermuda grass and other pastures. Short duration tests showed much higher gains (P <0.05), with values above 1.0 kg/animal/day. The number of animal/cycle (P <0.05) produced higher gains with fewer animals. Forest-grazing in association with Leucaena leucocephala cv Perú-graminaceae under dryland conditions produced mean daily gains above 0.800 kg/animal/day in the final stage of fattening bulls, based on food balances with adequate biological and economic results. The best behavior was observed in the shortest cycles, where the highest final weight/animal values were achieved, with fewer expenses and higher income

Bio-economic Impact of Strategic Changes in Murrah River Buffalo Management

The aim of this paper was to evaluate the effects of changes in the strategy to manage the bio-economic efficiency of a Murrah Buffalo production system in the province of Camagüey, Cuba, located 21º north and 77º west, 217 meters above sea level. The climate is tropical humid (Aw) of plains. The mean annual precipitations were 1 180 mm (71% between May and October), the temperatures were between 24 and 29 °C. The soil is brown, without carbonates, and brown-red fersiallitic. The system comprises 5 100 ha and has 536 workers/year. A strategy to introduce management changes in agro-technical, food, reproductive, replacement, health, salary policy, and training was implemented as part of an innovation package with a systemic and participatory approach. The evaluation lasted eight years, and it was critical to increase dairy production in more than 200 000 kg/year in 2012, in comparison to 2004, with improvements in natality and reduction of operational expenses of the system. It was concluded that the strategy had a determining effect on the system's indicators

Caribbean Corals in Crisis: Record Thermal Stress, Bleaching, and Mortality in 2005

BACKGROUND The rising temperature of the world's oceans has become a major threat to coral reefs globally as the severity and frequency of mass coral bleaching and mortality events increase. In 2005, high ocean temperatures in the tropical Atlantic and Caribbean resulted in the most severe bleaching event ever recorded in the basin. METHODOLOGY/PRINCIPAL FINDINGS Satellite-based tools provided warnings for coral reef managers and scientists, guiding both the timing and location of researchers' field observations as anomalously warm conditions developed and spread across the greater Caribbean region from June to October 2005. Field surveys of bleaching and mortality exceeded prior efforts in detail and extent, and provided a new standard for documenting the effects of bleaching and for testing nowcast and forecast products. Collaborators from 22 countries undertook the most comprehensive documentation of basin-scale bleaching to date and found that over 80% of corals bleached and over 40% died at many sites. The most severe bleaching coincided with waters nearest a western Atlantic warm pool that was centered off the northern end of the Lesser Antilles. CONCLUSIONS/SIGNIFICANCE Thermal stress during the 2005 event exceeded any observed from the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in over 150 years. Comparison of satellite data against field surveys demonstrated a significant predictive relationship between accumulated heat stress (measured using NOAA Coral Reef Watch's Degree Heating Weeks) and bleaching intensity. This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems and suggests a troubled future for tropical marine ecosystems under a warming climate.This work was partially supported by salaries from the NOAA Coral Reef Conservation Program to the NOAA Coral Reef Conservation Program authors. NOAA provided funding to Caribbean ReefCheck investigators to undertake surveys of bleaching and mortality. Otherwise, no funding from outside authors' institutions was necessary for the undertaking of this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Understanding Dwarf Galaxies in order to Understand Dark Matter

Much progress has been made in recent years by the galaxy simulation community in making realistic galaxies, mostly by more accurately capturing the effects of baryons on the structural evolution of dark matter halos at high resolutions. This progress has altered theoretical expectations for galaxy evolution within a Cold Dark Matter (CDM) model, reconciling many earlier discrepancies between theory and observations. Despite this reconciliation, CDM may not be an accurate model for our Universe. Much more work must be done to understand the predictions for galaxy formation within alternative dark matter models.Comment: Refereed contribution to the Proceedings of the Simons Symposium on Illuminating Dark Matter, to be published by Springe