(1) Modern, intensive agricultural practices have been attributed to the loss of insect biodiversity and abundance in agroecosystems for the last 80 years. The aim of this work is to test whether there are statistically significant differences in insect abundance between different zones and over time on the vineyard field. (2) The study was carried out in five intensive wine farms in Spain over a three-year period (2013–2015). Each field was divided into two zones, one where cover plants were planted, and another remained unchanged (without cover). (3) A clear trend to increase the average number of insect species and individuals throughout the years in all farms was observed. Moreover, the zones with cover plants showed a significant difference with respect to the zones without. (4) The use of permanent cover plants allows creating areas of refuge for the insects favouring their conservation and reducing the agriculture impact in the insect decline.
The rhizosphere is a hot spot of soil microbial activity and is largely fed by root exudation. The carbon (C) exudation flux, coupled with plant growth, is considered a strategy of plants to facilitate nutrient uptake. C exudation is accompanied by a release of nutrients. Nitrogen (N) and phosphorus (P) co-limit the productivity of the plant-microbial system. Therefore, the C:N:P stoichiometry of exudates should be linked to plant nutrient economies, plant functional traits (PFT) and soil nutrient availability. We aimed to identify the strongest links in C:N:P stoichiometry among all rhizosphere components. A total of eight grass species (from conservative to exploitative) were grown in pots under two different soil C:nutrient conditions for a month. As a result, a wide gradient of plant–microbial–soil interactions were created. A total of 43 variables of plants, exudates, microbial and soil C:N:P stoichiometry, and PFTs were evaluated. The variables were merged into four groups in a network analysis, allowing us to identify the strongest connections among the variables and the biological meaning of these groups. The plant–soil interactions were shaped by soil N availability. Faster-growing plants were associated with lower amounts of mineral N (and P) in the soil solution, inducing a stronger competition for N with microorganisms in the rhizosphere compared to slower-growing plants. The plants responded by enhancing their N use efficiency and root:shoot ratio, and they reduced N losses via exudation. Root growth was supported either by reallocated foliar reserves or by enhanced ammonium uptake, which connected the specific leaf area (SLA) to the mineral N availability in the soil. Rapid plant growth enhanced the exudation flux. The exudates were rich in C and P relative to N compounds and served to release surplus metabolic products. The exudate C:N:P stoichiometry and soil N availability combined to shape the microbial stoichiometry, and N and P mining. In conclusion, the exudate flux and its C:N:P stoichiometry reflected the plant growth rate and nutrient constraints with a high degree of reliability. Furthermore, it mediated the plant–microbial interactions in the rhizosphere.
An in-depth descriptive approach to the dynamics of the urban population is fundamental as a first step towards promoting effective planning and designing processes in cities. Understanding the behavioral aspects of human activities can contribute to their effective management and control. We present a framework, based on statistical methods, for studying the spatio-temporal distribution of geolocated tweets as a proxy for where and when people carry out their activities. We have evaluated our proposal by analyzing the distribution of collected geolocated tweets over a two-week period in the summer of 2017 in Lisbon, London, and Manhattan. Our proposal considers a negative binomial regression analysis for the time series of counts of tweets as a first step. We further estimate a functional principal component analysis of second-order summary statistics of the hourly spatial point patterns formed by the locations of the tweets. Finally, we find groups of hours with a similar spatial arrangement of places where humans develop their activities through hierarchical clustering over the principal scores. Social media events are found to show strong temporal trends such as seasonal variation due to the hour of the day and the day of the week in addition to autoregressive schemas. We have also identified spatio-temporal patterns of clustering, i.e., groups of hours of the day that present a similar spatial distribution of human activities.
Introducción. Es difícil adaptar o formular nuevas estrategias para el control del dengue en las áreas rurales debido a la dispersión de los hogares y a la falta de conocimiento sobre la presencia y el comportamiento del vector en estas áreas. El análisis de los datos espaciales podría ayudar a comprender las dinámicas temporales y espaciales relacionadas con la transmisión de enfermedades transmitidas por vectores en las zonas rurales y, por lo tanto, contribuir a la prevención y el control del dengue.Objetivo. Determinar la probabilidad de la presencia del vector del dengue, Aedes aegypti, en el área rural de los municipios de Anapoima y La Mesa, Cundinamarca, Colombia.Materiales y métodos. Se visitaron 102 viviendas del área rural, se inspeccionaron los criaderos potenciales del mosquito A. aegypti y se capturaron las formas adultas encontradas en su interior. La probabilidad de la presencia o la ausencia del vector en el área de estudio, se estableció mediante el método de interpolación espacial kriging.Resultados. La región con mayor probabilidad para la presencia del vector se encontró en la parte central, cerca de los centros urbanos de los dos municipios.Conclusión. Los análisis de las dinámicas espacio-temporales de los vectores de enfermedades pueden utilizarse en los sistemas para su vigilancia, con el fin de complementar los métodos usados actualmente, optimizar la determinación de las áreas de intervención de control vectorial y ahorrar recursos.
Este artículo presenta el análisis y la metodología de implementación de la técnica de localización de raíces de sistemas dinámicos para la planeación de rutas libres de obstáculos para robots móviles. En primera instancia, se realiza un análisis e identificación del comportamiento morfológico de las trayectorias en dependencia de la ubicación de las raíces en el plano complejo, identificándose el tipo de trayectorias curvas y la característica de atracción y repulsión de estas en presencia de otras raíces, de forma similar al obtenido con la técnica de cargas de potencial artificial. Se plantea una metodología para implementación de esta técnica para la planeación de rutas de robots móviles, partiendo de tres métodos diferentes de ubicación de las raíces para los obstáculos presentes en el escenario. Dichas técnicas varían dependiendo de los puntos clave del obstáculo que son seleccionados para las raíces, tales como los bordes, los cruces con las trayectoria original, el centro y los vértices. Finalmente, se realiza un análisis de funcionamiento de la técnica en general y de la efectividad cada uno de los métodos evaluados, bajo 20 pruebas para cada uno, obteniendo un valor del 65% para el método seleccionado. También se proponen modificaciones o posibles mejoras a la metodología propuesta.
El modelamiento en Matlab del proceso de la producción de panela está dirigido a toda la gente interesada en el control de procesos agroin-dustriales, específicamente a los productores de panela, con el fin de brindar una contribución al desarrollo tecnológico de esta agroindustria; sin embargo, es importante resaltar que para el entendimiento de este documento se requieren conocimientos de control y termodinámica. El modelo matemático desarrollado está dividido dos diferentes procesos involucrados en la obtención del producto final (panela): a) el control de la concentración de azúcar y b) el control de nivel en los efectos del evaporador. A lo largo del documento el análisis está enfocado a que estos dos sistemas sugieran el controlador ideal para la operación del evaporador.
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