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95 resultados, página 2 de 10

Catching-up with genetic progress: Simulation of potential production for modern wheat cultivars in the Netherlands

João Vasco Silva Frits K. Van Evert Pytrik Reidsma (2023, [Artículo])

Context: Wheat crop growth models from all over the world have been calibrated on the Groot and Verberne (1991) data set, collected between 1982 and 1984 in the Netherlands, in at least 28 published studies to date including various recent ones. However, the recent use of this data set for calibration of potential yield is questionable as actual Dutch winter wheat yields increased by 3.1 Mg ha-1 over the period 1984 – 2015. A new comprehensive set of winter wheat experiments, suitable for crop model calibration, was conducted in Wageningen during the growing seasons of 2013–2014 and of 2014–2015. Objective: The present study aimed to quantify the change of winter wheat variety traits between 1984 and 2015 and to examine which of the identified traits explained the increase in wheat yield most. Methods: PCSE-LINTUL3 was calibrated on the Groot and Verberne data (1991) set. Next, it was evaluated on the 2013–2015 data set. The model was further recalibrated on the 2013–2015 data set. Parameter values of both calibrations were compared. Sensitivity analysis was used to assess to what extent climate change, elevated CO2, changes in sowing dates, and changes in cultivar traits could explain yield increases. Results: The estimated reference light use efficiency and the temperature sum from anthesis to maturity were higher in 2013–2015 than in 1982–1984. PCSE-LINTUL3, calibrated on the 1982–1984 data set, underestimated the yield potential of 2013–2015. Sensitivity analyses showed that about half of the simulated winter wheat yield increase between 1984 and 2015 in the Netherlands was explained by elevated CO2 and climate change. The remaining part was explained by the increased temperature sum from anthesis to maturity and, to a smaller extent, by changes in the reference light use efficiency. Changes in sowing dates, biomass partitioning fractions, thermal requirements for anthesis, and biomass reallocation did not explain the yield increase. Conclusion: Recalibration of PCSE-LINTUL3 was necessary to reproduce the high wheat yields currently obtained in the Netherlands. About half of the reported winter wheat yield increase was attributed to climate change and elevated CO2. The remaining part of the increase was attributed to changes in the temperature sum from anthesis to maturity and, to a lesser extent, the reference light use efficiency. Significance: This study systematically addressed to what extent changes in various cultivar traits, climate change, and elevated CO2 can explain the winter wheat yield increase observed in the Netherlands between 1984 and 2015.

Light Use Efficiency Potential Yield CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CROP MODELLING LIGHT PHENOLOGY MAXIMUM SUSTAINABLE YIELD TRITICUM AESTIVUM WINTER WHEAT

Shopping centers at zmcm. The companies, location and production of a neoliberal urban space

Dante-Guillermo Celis-Galindo (2021, [Artículo, Artículo])

This work aims to analyze different aspects of shopping center at the Metropolitan Zone of Mexico City as location, opening year and developer company. Also it will identify diverse characteristics, economic and political phases in the country as well as the role of the development companies and shopping centers as a producers of a neoliberal urban space. This paper presents the way shopping centers importance has growth and how it had become in a neoliberal city characteristic; with this the characteristics of these urban works are visualized and related with their construction companies and local governments which has caused the transformation of the city. After conducting a census, with more than two hundred shopping centers, the study was delimited to those with the greatest significance by size, location and developer. At the beginning of the paper, the characteristics that shopping malls should have for the realization of this work are mentioned. In a first section an approach is made to the theoretical elements of the city and the shopping center and therefore identifying the developers that most  nfluence this process; the second section addresses the characteristics of places by location and the characteristics that urban planners have depending on the area where they are; the third section discusses the years of opening, the squares and relates to government administrations and the economic characteristics of the country; and finally, a tour of the urban regulations in Mexico City and its latest modifications is made.

shopping center neoliberalism space urban space construction company centro comercial neoliberalismo espacio espacio urbano empresa constructora HUMANIDADES Y CIENCIAS DE LA CONDUCTA HUMANIDADES Y CIENCIAS DE LA CONDUCTA