On the principle of competitive exclusion in metapopulation models

In this paper we present and analyse a simple two populations model with migrations among two different environments. The populations interact by competing for resources. Equilibria are investigated. A proof for the boundedness of the populations is provided. A kind of competitive exclusion principle for metapopulation systems is obtained. At the same time we show that the competitive exclusion principle at the local patch level may be prevented to hold by the migration phenomenon, i.e. two competing populations may coexist, provided that only one of them is allowed to freely move or that migrations for both occur just in one direction

Effects of Ground-State Correlations on High Energy Scattering off Nuclei: the Case of the Total Neutron-Nucleus Cross Section

With the aim at quantitatively investigating the longstanding problem concerning the effect of short range nucleon-nucleon correlations on scattering processes at high energies, the total neutron-nucleus cross section is calculated within a parameter-free approach which, for the first time, takes into account, simultaneously, central, spin, isospin and tensor nucleon-nucleon (NN) correlations, and Glauber elastic and Gribov inelastic shadowing corrections. Nuclei ranging from 4He to 208Pb and incident neutron momenta in the range 3 GeV/c - 300 GeV/c are considered; the commonly used approach which approximates the square of the nuclear wave function by a product of one-body densities is carefully analyzed, showing that NN correlations can play a non-negligible role in high energy scattering off nuclei.Comment: 5 pages, 3 figure

2018 Watermelon Variety Evaluation in Indiana

This is a compilation of 20 research trial reports from four land-grant universities in the Midwestern United States. Crops include cantaloupe, pickling cucumber, pepper, potato, pumpkin, summer squash and zucchini, sweet corn, tomato, and watermelon. Somecrops were evaluated in high tunnels or hoophouses. Most trials evaluated different cultivars or varieties. One report addressed plant spacing for sweet corn and one addressed soil block for production of tomato seedlings. A list of vegetable seed sources and a list of other online sources of vegetable trial reports are also included

Actividades ecológicas en el conocimiento de protección del medio ambiente. I.E. \"Horacio Zevallos Gámez\"; 2018

La presente investigación tuvo como propósito mejorar el conocimiento de la protección del medio ambiente aplicando actividades ecológicas que contribuyen en los alumnos del segundo año de secundaria. El tipo de investigación empleado es el aplicado con diseño cuasi experimental de dos grupos con pre test y post test. Se trabajó con una muestra de 21 estudiantes del segundo grado B? de educación secundaria de la Institución Educativa ?Horacio Zevallos Gámez del Centro Poblado Rayle Rumi. Para el recojo de información se empleó un cuestionario sobre protección del medio ambiente las que fue procesado mediante el paquete estadístico SPSS; las mismas que permitió obtener la información requerida. Existe diferencia de media entre resultados de pre y post test de 4,857 con desviación estándar de 5, 062. Asimismo, en un 95% de confianza se obtiene un nivel de significancia de 0,000Trabajo de Investigació

Comparison of the Results of Analytical and Numerical Models of Pre-Reinforcement in Shallow Tunnels

AbstractThe steel pipe umbrella is a widely used technology when tunnelling in weak soils in order to create pre-support ahead of the tunnel face. The design of steel pipes is frequently done through simplified analytical approaches which are easy to apply but require proper assessment of the loads acting on the pipe. To provide information on this key design aspect, the results of the comparison between a three-dimensional numerical model developed with the code FLAC 3D and an analytical model based on the approach of a beam on yielding supports is presented and discussed. The comparison refers to a shallow tunnel with an overburden of three times its diameter for two different types of weak rock masses. The obtained results provide suggestions about the load that has to be applied in the analytical model for the design phase

“La infografía periodística vista desde un medio estatal : diseño de una unidad de infografía en el Diario Oficial El Peruano”

El presente estudio abordó la gestión y desarrollo de un proyecto de comunicación para la mejora de procesos de producción de contenidos del área de infografía del Diario Oficial El Peruano y la Agencia de Noticias Andina. Con esta mira, la revisión de la gestión de factores clave en departamentos de infografía internacional dentro de una metodología de estudio de casos fueron los pilares para demarcar los lineamientos y objetivos del proyecto. Todas las acciones llevadas a cabo han permitido mejorar el flujo de trabajo interno con las secciones y además la propuesta gráfica que llega a los lectores del rotativo.The present study addressed the management and development of a communication project for the improvement of content production processes in the infographic area of the Official Gazette El Peruano and the Andean News Agency. With this in mind, the review of the management of key factors in international infographic departments within a case study methodology were the pillars to demarcate the guidelines and objectives of the project. All the actions carried out have allowed to improve the internal work flow with the sections and also the graphic proposal that reaches the readers of the newspaper.Tesi

A dataset of leaf inclination angles for temperate and boreal broadleaf woody species

International audienceNo abstract availabl