Baja presión en aspersores de impacto en coberturas de riego: análisis técnico y agronómico

La eficiencia energética en riego presurizado se ha abordado desde la gestión hidráulica de las infraestructuras de red y la eficiencia en los bombeos, sin embargo, es necesario analizar los ahorros que pueden realizarse a escala de parcela. Resultados preliminares indican que la reducción de la presión de funcionamiento de un aspersor de impacto de 300 kPa a 200 kPa ligeramente reduce la uniformidad del riego. En este trabajo se evalúa en campo la calidad del riego y los resultados agronómicos de tres configuraciones aspersor+presión: 1) un aspersor de impacto convencional trabajando a 300 kPa (AC 300), 2) un aspersor convencional trabajando a 200 kPa (AC 200) y 3) un aspersor modificado con una pequeña placa deflectora sobre el brazo de impacto trabajando a 200 kPa (APD 200). En una parcela experimental de cobertura total formada por 12 subparcelas, se realizó un ensayo en bloques al azar sobre un cultivo de maíz durante la campaña 2015. Se caracterizaron las condiciones meteorológicas (velocidad y dirección del viento) de los riegos aplicados al maíz. Para cada tratamiento se realizaron ensayos de uniformidad, evaluaciones agronómicas, cosecha manual de biomasa aérea y cosecha de grano. Los resultados indican que la uniformidad media evaluada no fue significativamente diferente entre tratamientos. La biomasa y producción de grano del tratamiento de 300 kPa resultaron menores que las de los tratamientos a 200 kPa (AC 200 y APD 200), no resultando significativas las diferencias entre ambos tratamientos de 200 kPa. Se detectó un problema en el crecimiento de cultivo que afectó principalmente a las subparcelas de 300 kPa, por lo que los resultados deben de considerarse con cuidado y realizar el ensayo en una o dos temporadas más.Ministerio de Economía y Competitivida

Development of a portable leaf photosynthesis and volatile organic compounds emission system.

Understanding how plant carbon metabolism responds to environmental variables such as light is central to understanding ecosystem carbon cycling and the production of food, biofuels, and biomaterials. Here, we couple a portable leaf photosynthesis system to an autosampler for volatile organic compounds (VOCs) to enable field observations of net photosynthesis simultaneously with emissions of VOCs as a function of light. Following sample collection, VOCs are analyzed using automated thermal desorption-gas chromatograph-mass spectrometry (TD-GC-MS). An example is presented from a banana plant in the central Amazon with a focus on the response of photosynthesis and the emissions of eight individual monoterpenes to light intensity. Our observations reveal that banana leaf emissions represent a 1.1 +/- 0.1% loss of photosynthesis by carbon. Monoterpene emissions from banana are dominated by trans-β-ocimene, which accounts for up to 57% of total monoterpene emissions at high light. We conclude that the developed system is ideal for the identification and quantification of VOC emissions from leaves in parallel with CO2 and water fluxes.The system therefore permits the analysis of biological and environmental sensitivities of carbon metabolism in leaves in remote field locations, resulting in the emission of hydrocarbons to the atmosphere.•A field-portable system is developed for the identification and quantification of VOCs from leaves in parallel with leaf physiological measurements including photosynthesis and transpiration.•The system will enable the characterization of carbon and energy allocation to the biosynthesis and emission of VOCs linked with photosynthesis (e.g. isoprene and monoterpenes) and their biological and environmental sensitivities (e.g. light, temperature, CO2).•Allow the development of more accurate mechanistic global VOC emission models linked with photosynthesis, improving our ability to predict how forests will respond to climate change. It is our hope that the presented system will contribute with critical data towards these goals across Earth's diverse tropical forests

Interacting universes and the cosmological constant

We study some collective phenomena that may happen in a multiverse scenario. First, it is posed an interaction scheme between universes whose evolution is dominated by a cosmological constant. As a result of the interaction, the value of the cosmological constant of one of the universes becomes very close to zero at the expense of an increasing value of the cosmological constant of the partner universe. Second, we found normal modes for a 'chain' of interacting universes. The energy spectrum of the multiverse, being this taken as a collective system, splits into a large number of levels, some of which correspond to a value of the cosmological constant very close to zero. We finally point out that the multiverse may be much more than the mere sum of its parts.Comment: 7 page

Quantum state of the multiverse

A third quantization formalism is applied to a simplified multiverse scenario. A well defined quantum state of the multiverse is obtained which agrees with standard boundary condition proposals. These states are found to be squeezed, and related to accelerating universes: they share similar properties to those obtained previously by Grishchuk and Siderov. We also comment on related works that have criticized the third quantization approach.Comment: 15 pages, 2 figure

Los egresados de la UAM en el mercado de trabajo : investigación evaluativa sobre la calidad de la oferta de servicios educativos

1 archivo PDF (155 páginas)El libro está constituido en dos secciones: La primera comprende una breve introducción del proyecto, así como los principales criterios metodológicos que guiaron la investigación. La segunda comprende particularidades de la UAM, los resultados de la investigación, descripción de los egresados, análisis de los ritmos de inserción laboral, un esbozo del mercado laboral al cual se incorporan los egresados y finalmente se analizan algunos rasgos generales del desempeño profesional

Genetic differentiation and admixture between sibling allopolyploids in the Dactylorhiza majalis complex

Allopolyploidization often happens recurrently, but the evolutionary significance of its iterative nature is not yet fully understood. Of particular interest are the gene flow dynamics and the mechanisms that allow young sibling polyploids to remain distinct while sharing the same ploidy, heritage and overlapping distribution areas. By using eight highly variable nuclear microsatellites, newly reported here, we investigate the patterns of divergence and gene flow between 386 polyploid and 42 diploid individuals, representing the sibling allopolyploids Dactylorhiza majalis s.s. and D. traunsteineri s.l. and their parents at localities across Europe. We make use in our inference of the distinct distribution ranges of the polyploids, including areas in which they are sympatric (that is, the Alps) or allopatric (for example, Pyrenees with D. majalis only and Britain with D. traunsteineri only). Our results show a phylogeographic signal, but no clear genetic differentiation between the allopolyploids, despite the visible phenotypic divergence between them. The results indicate that gene flow between sibling Dactylorhiza allopolyploids is frequent in sympatry, with potential implications for the genetic patterns across their entire distribution range. Limited interploidal introgression is also evidenced, in particular between D. incarnata and D. traunsteineri. Altogether the allopolyploid genomes appear to be porous for introgression from related diploids and polyploids. We conclude that the observed phenotypic divergence between D. majalis and D. traunsteineri is maintained by strong divergent selection on specific genomic areas with strong penetrance, but which are short enough to remain undetected by genotyping dispersed neutral markers.UE FWF; P22260UE: Y66