Búsqueda avanzada


Área de conocimiento




124 resultados, página 3 de 10

Diversifying with grain legumes amplifies carbon in management-sensitive soil organic carbon pools on smallholder farms

Regis Chikowo Sieglinde Snapp (2023, [Artículo])

Crop diversification with grain legumes has been advocated as a means to increase agroecological resilience, diversify livelihoods, boost household nutrition, and enhance soil health and fertility in cereal-based cropping systems in sub-Saharan Africa and around the world. Soil organic carbon (SOC) is a primary indicator of soil health and there is limited data regarding SOC pools and grain legume diversification on smallholder farms where soils are often marginal. In Malawi, a range of legume diversification options are under investigation, including rotations and a doubled-up legume rotation (DLR) system in which two compatible legumes are intercropped and then rotated with a cereal. The impact of the DLR system on SOC has not yet been determined, and there is a lack of evidence regarding SOC status over a gradient of simple to complex grain legume diversified systems. We address this knowledge gap by evaluating these systems in comparison to continuous sole maize (Zea mays L.) at three on-farm trial sites in central Malawi. After six years of trial establishment, we measured SOC in bulk soils and aggregate fractions and in faster cycling SOC pools that respond more rapidly to management practices, including water extractable organic carbon (WEOC), particulate organic matter carbon (POM-C), potentially mineralizable carbon (C), and macroaggregate C. Cropping treatment differences were not seen in bulk SOC or total N, but they were apparent in SOC pools with a shorter turnover time. The DLR system of intercropped pigeonpea (Cajanus cajan (L.) Millsp.) and groundnut (Arachis hypogaea L.) rotated with maize had higher WEOC, POM-C, potentially mineralizable C, macroaggregate and microaggregate C values than continuous maize. Of the single legume rotations, the pigeonpea-maize rotation had more mineralizable C and microaggregate C compared to continuous maize, while the groundnut-maize rotation had similar C values to the maize system. Overall, this study shows the potential for crop rotations diversified with grain legumes to enhance C in management sensitive SOC pools, and it is one of the first reports to show this effect on smallholder farm sites.

Crop Diversification Water Extractable Organic Carbon CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA DIVERSIFICATION LEGUMES PARTICULATE ORGANIC MATTER SOIL ORGANIC CARBON

Nitrogen fertilizer application alters the root endophyte bacterial microbiome in maize plants, but not in the stem or rhizosphere soil

Alejandra Miranda Carrazco Yendi Navarro-Noya Bram Govaerts Nele Verhulst Luc Dendooven (2022, [Artículo])

Plant-associated microorganisms that affect plant development, their composition, and their functionality are determined by the host, soil conditions, and agricultural practices. How agricultural practices affect the rhizosphere microbiome has been well studied, but less is known about how they might affect plant endophytes. In this study, the metagenomic DNA from the rhizosphere and endophyte communities of root and stem of maize plants was extracted and sequenced with the “diversity arrays technology sequencing,” while the bacterial community and functionality (organized by subsystems from general to specific functions) were investigated in crops cultivated with or without tillage and with or without N fertilizer application. Tillage had a small significant effect on the bacterial community in the rhizosphere, but N fertilizer had a highly significant effect on the roots, but not on the rhizosphere or stem. The relative abundance of many bacterial species was significantly different in the roots and stem of fertilized maize plants, but not in the unfertilized ones. The abundance of N cycle genes was affected by N fertilization application, most accentuated in the roots. How these changes in bacterial composition and N genes composition might affect plant development or crop yields has still to be unraveled.

Bacterial Community Structure DArT-Seq Bacterial Community Functionality Genes Involved in N Cycling CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA AGRICULTURAL PRACTICES MAIZE RHIZOSPHERE STEMS NITROGEN FERTILIZERS

EFFICIENT FLUORESCENT AND PHOSPHORESCENT OLEDs BY SPIN COATING TECHNIQUE AND A NEW ANODE BASED ON CONDUCTIVE PEDOT:PSS

Luis Abraham Lozano Hernández (2020, [Tesis de doctorado])

"Fluorescent and phosphorescent Organic Light Emitting Diode (OLED) devices were fabricated by solution process and optimized. From their basic characterization (J-V-L curves, electroluminescence spectra) external quantum efficiency (EQE) was calculated. Two small molecule, carbazole derivatives (CZ-1 and CZ-2), previously reported and used for OLEDs showed very good luminances (~ 4000 cd/m2) and current densities (< 200 mA/cm2) resulting in a high EQE (9.5 %). Likewise, fluorescent OLEDs based in the new polymer PF-2F presented an acceptable performance even on a simple architecture with a good EQE (2.6 %), photoluminescence quantum yield (PLQY) about 1 and excellent properties of processability. The influence of its CF3 group in the optical, chemical, electronic and mechanical properties in OLEDs was determined.

Also, a new family of three fluorescent oligomers (BT-F32, BT-F42 and BT-F52) with excellent properties in solution, high PLQY (~1) and highly luminescent, were used in simple and multilayer OLEDs achieving a very high luminance (29 499 cd/m2). These oligomers have different chain lengths, which influence the device luminance, efficiency and their lifetime. Lifetime was monitored and the stretched exponential decay (SED) model was used in order to obtain the device half-life (LT50). Also, phosphorescent devices, based on a host/guest system (PVK:Ir(ppy)3), were prepared, the influence of the electron transport layer (ETL) into the electron/hole ratio was analyzed.

By using a new proposed method, a PEDOT:PSS anode was developed and applied in rigid and flexible substrates, with low sheet resistance (40 Ω/□) and acceptable transmittance (> 85%). This new proposed method consists in volume evaporation, in which basically the loss of water induces closeness among the conductive fractions of PEDOT. This PEDOT:PSS anode easy of fabricating following an economical procedure could be applied not just in OLEDs but in other optoelectronic devices such as organic photovoltaic cells (OPVs), perovskite solar cells (PeSCs), etc."

OLEDs Fluorescence Phosphorescence PEDOT:PSS Polymer Anode INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA ELECTRÓNICA DISPOSITIVOS SEMICONDUCTORES DISPOSITIVOS SEMICONDUCTORES

Servicios digitales públicos: el IMPI y la emisión de títulos de patente que realiza

Pamela Serrano Magaña (2023, [Otro, Trabajo de grado, maestría])

Las Tecnologías de la Información y Comunicación (TIC) han logrado acercar a la población a contenidos y formas de intercambio de información que anteriormente no eran posibles; el Internet ha derrumbado fronteras entre las sociedades, los gobiernos, el conocimiento y las oportunidades, creando a su vez nuevas necesidades para caer en el círculo virtuoso de la innovación.

Este artículo plantea una transformación integral en una etapa digital específica dentro de los procesos internos del IMPI, desde el expediente físico hacia el expediente digital para automatizar los procesos de emisión de títulos de concesión de patentes de invención lo que resultaría en una reducción del índice de errores humanos involuntarios, así como la mejora en la atención a los usuarios, al ofrecer mayor certeza en los servicios proporcionados y mayor seguridad en el tratamiento de su información, así como un apego a las normas jurídicas aplicables. El objetivo de esta implementación es reducir el índice de equivocaciones en la documentación oficial emitida disminuyendo en consecuencia, los retrasos y las incidencias fortuitas, y para dicho fin se proponen dos soluciones. La primera, el desarrollar un nuevo módulo dentro del sistema principal existente, que permitirá exportar los datos y generar el título directamente en el formato requerido. La segunda, es la utilización de tecnología de automatización robótica de procesos o RPA por sus siglas en inglés (Robotic Process Automation) para hacer uso de una herramienta que sustituya a la transcripción manual por una transcripción automática.

Digitalización Servicios digitales Gobierno electrónico Instituto Mexicano de la Propiedad Industrial INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS CIENCIAS TECNOLÓGICAS

Addressing agricultural labour issues is key to biodiversity-smart farming

Thomas Daum Frédéric Baudron Matin Qaim Ingo Grass (2023, [Artículo])

There is an urgent need for agricultural development strategies that reconcile agricultural production and biodiversity conservation. This is especially true in the Global South where population growth is rapid and much of the world's remaining biodiversity is located. Combining conceptual thoughts with empirical insights from case studies in Indonesia and Ethiopia, we argue that such strategies will have to pay more attention to agricultural labour dynamics. Farmers have a strong motivation to reduce the heavy toil associated with farming by adopting technologies that save labour but can negatively affect biodiversity. Labour constraints can also prevent farmers from adopting technologies that improve biodiversity but increase labour intensity. Without explicitly accounting for labour issues, conservation efforts can hardly be successful. We hence highlight the need for biodiversity-smart agriculture, that is farming practices or systems that reconcile biodiversity with land and labour productivity. Our empirical insights suggest that technological and institutional options to reconcile farmers' socio-economic goals and biodiversity conservation exist but that more needs to be done to implement such options at scale.

Land Sharing Trade-Offs CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA AGRICULTURAL DEVELOPMENT BIODIVERSITY CONSERVATION LABOUR SUSTAINABILITY