Evolution of the spherical cavity radius generated around a subsurface emitter

The emitter discharge in subsurface drip irrigation can be affected by soil properties. A positive pressure develops at the emitter outlet where a spherical cavity is assumed to form. In steady-state conditions, the pressure in the soil relates to soil hydraulic 5 properties, the emitter discharge, and the cavity radius. This pressure in the soil is very sensitive to the cavity radius. In this paper, the development of the cavity around the emitter outlet was measured for various emitter discharges in laboratory tests carried out in containers with uniform loamy soils. A trend between soil pressure and emitter discharge was established that illustrates the performance of buried emitters in the 10 field. Its application to the prediction of water distribution in subsurface drip irrigation units and its effect on the estimation of irrigation performance is also show

Water distribution in laterals and units of subsurface drip irrigation. II: Field evaluation.

The performance of drip irrigation and subsurface drip irrigation (SDI) laterals has been compared. Two emitter models (one compensating and the other noncompensating) were assessed. Field tests were carried out with a pair of laterals working at the same inlet pressure. A procedure was developed that recorded head pressures at both lateral extremes and inlet flow during irrigation. Both models showed similar behavior and soil properties affected their discharge. On the other hand, the performance of a field SDI unit of compensating emitters was characterized by measuring pressures at different points and inlet flow. Finally, the distribution of water and soil pressure in the laterals and the unit were predicted and irrigation uniformity and soil pressure variability were also determined. Predictions agreed reasonably well with the experimental observations. Thus, the methodology proposed could be used to support the decision making for the design and management of SDI system

La figura de la coautoría impropia: una aproximación desde la jurisprudencia de la Corte Suprema de Justicia

Este artículo pretende abordar un tema fundamental en la discusión actual de la dogmática jurídico penal: la determinación de quién cometió el delito. Al respecto, muchas teorías se han estructurado en la corte suprema de justicia en Colombia, dentro de las que se pueden destacar, la reciente teoría de la coautoría impropia de donde se desprende que la figura de la participación, particularmente de la complicidad, hoy por hoy haya caído en desuso en la jurisprudencia de este tribunal. Por ello, el presente artículo tiene como finalidad realizar un análisis crítico de la figura de la coautoría impropia, a partir de tres elementos: en primer lugar, parte de las observaciones de la jurisprudencia de este tribunal, en segundo lugar, estudia las teorías que se han planteado sobre el particular y finalmente, visibiliza el estado actual de la discusión. En consecuencia, del análisis jurisprudencial de la situación se evaluará la aplicación de la figura en la actualidad frente a los postulados dogmáticos que guían la autoría y la participación en Colombia.The time used for this article, pretends to aboard fundamental topic about the criminal theory; definition about that the person concerned committed a criminal offence. A lot of theories about this topic is structured in supreme court of justice, one of this is about improper co-authorship, and the participation figure is fell into disuse in the jurisprudence of this court. This is the reason because on this opportunity we want to do a critical legal studie about this figure about improper co-authorship analyzing in first time the jurisprudence of this court looking all theories explained and the-state-of-the-art. This way the studie about this topic allows doing an assessment about application of this figure in face of the postulates of the authorship and participation in Colombia

Editorial

During the 21st century teachers and students have been witnesses of the unavoidable inclusion of the technology in education, specifically in the teaching-learning instruction, thus, the TIC (Technology of the information and communication), LKT (Learning and Knowledge Technologies), and TEP (Technologies for Empowerment and Participation) are used to support and strengthen the pedagogies in all areas of knowledge. Learning to learn in the digital age and the use of learning technologies are the new trends students and teachers are living; as a mandatory approach, nowadays education must be involved in the emerging pedagogies which are focused to encourage students and teachers’ interaction by means of technology, thus, the connection between theory and practice is done through the mediation of technological tools which also represent the management of knowledge in modern times. In the field of languages acquisition, these tools have become an opportunity to improve the use of foreign languages, especially because the class time is not enough to foster students’ communication skills; hence, technology is important in order to support and motivate students´ autonomous work; in our context, this is a way students acquire the necessary expertise to communicate with property in different settings. In addition to the immediate communication, further reading and research are ways to build students’ knowledge; besides, teachers have the possibility to offer students an extensive bibliography and academic resources that not only support students’ language learning but about topics of their own field of study according to their interests and learning needs; besides, it can be reinforced by the databases which are rich in the latest materials that are usually written in the original language (English, French, Chinese, Mandarin, Italian, Spanish, etc.), so students can consult in the original source and practice the foreign language. Finally, the use of technologies in education as well as in language acquisitions, represent meaningful strategies teachers and students must use to encourage the teaching and learning processes, they contribute to build knowledge and develop other skills necessary for current productivity such as team work, autonomy, information management, communication, languages proficiency, among others

Emitter discharge variability of subsurface drip irrigation in uniform soils: effect on water-application uniformity

Emitter discharge of subsurface drip irrigation (SDI) decreases as a result of the overpressure in the soil water at the discharge orifice. In this paper, the variation in dripper discharge in SDI laterals is studied. First, the emitter coefficient of flow variation CVq was measured in laboratory experiments with drippers of 2 and 4 L/h that were laid both on the soil and beneath it. Additionally, the soil pressure coefficient of variation CVhs was measured in buried emitters. Then, the irrigation uniformity was simulated in SDI and surface irrigation laterals under the same operating conditions and uniform soils; sandy and loamy. CVq was similar for the compensating models of both the surface and subsurface emitters. However, CVq decreased for the 2-L/h non-compensating model in the loamy soil. This shows a possible self-regulation of non-compensating emitter discharge in SDI, due to the interaction between effects of emitter discharge and soil pressure. This resulted in the irrigation uniformity of SDI non-compensating emitters to be greater than surface drip irrigation. The uniformity with pressure-compensating emitters would be similar in both cases, provided the overpressures in SDI are less than or equal to the compensation range lower limit

La calculadora gráfica cómo recurso didáctico en el aprendizaje del cálculo de integrales dobles

El tema de integrales dobles ofrece un conjunto de dificultades al estudiante que son los principales obstáculos para el aprendizaje de esta materia. Estas dificultades aparecen en la determinación gráfica de la región de integración, la determinación de los límites de integración y el cálculo de las integrales iteradas con límites variables (Carlos, Martín, Otero y Rivero, 1986). El presente trabajo muestra una experiencia metodológica en la cual se utiliza la calculadora gráfica. La calculadora no se utiliza como herramienta para hacer cálculos sino como un recurso didáctico, contribuyendo a crear un ambiente adecuado en el aprendizaje. El uso de la calculadora gráfica permite establecer un adecuado control por operaciones en las primeras etapas del proceso de asimilación de los conocimientos como reclaman las modernas teorías de enseñanza (Talízina, 1988)

Estudio comparativo de la resistencia de variedades de tomate para industria mediante análisis estadísticos no paramétricos.

Se exponen los ensayos de resistencia y dureza 1levados a cabo con las distintas variedades ensayada a lo largo de los tres últimos años, así como la técnica empleada en su análisis. Los datos observados se sometieron a u n completo estudio estadístico no paramétrico que resulta idóneo, dentro del objetivo clasificar a las variedades según su resistencia a la compresión y a la punción