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134 resultados, página 6 de 10

Automated in-season rice crop mapping using Sentinel time-series data and Google Earth Engine: A case study in climate-risk prone Bangladesh

Mustafa Kamal Timothy Joseph Krupnik (2024, [Artículo])

High-resolution mapping of rice fields is crucial for understanding and managing rice cultivation in countries like Bangladesh, particularly in the face of climate change. Rice is a vital crop, cultivated in small scale farms that contributes significantly to the economy and food security in Bangladesh. Accurate mapping can facilitate improved rice production, the development of sustainable agricultural management policies, and formulation of strategies for adapting to climatic risks. To address the need for timely and accurate rice mapping, we developed a framework specifically designed for the diverse environmental conditions in Bangladesh. We utilized Sentinel-1 and Sentinel-2 time-series data to identify transplantation and peak seasons and employed the multi-Otsu automatic thresholding approach to map rice during the peak season (April–May). We also compared the performance of a random forest (RF) classifier with the multi-Otsu approach using two different data combinations: D1, which utilizes data from the transplantation and peak seasons (D1 RF) and D2, which utilizes data from the transplantation to the harvest seasons (D2 RF). Our results demonstrated that the multi-Otsu approach achieved an overall classification accuracy (OCA) ranging from 61.18% to 94.43% across all crop zones. The D2 RF showed the highest mean OCA (92.15%) among the fourteen crop zones, followed by D1 RF (89.47%) and multi-Otsu (85.27%). Although the multi-Otsu approach had relatively lower OCA, it proved effective in accurately mapping rice areas prior to harvest, eliminating the need for training samples that can be challenging to obtain during the growing season. In-season rice area maps generated through this framework are crucial for timely decision-making regarding adaptive management in response to climatic stresses and forecasting area-wide productivity. The scalability of our framework across space and time makes it particularly suitable for addressing field data scarcity challenges in countries like Bangladesh and offers the potential for future operationalization.

Synthetic Aperture Radar Random Forest Boro Rice In-Season Maps CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA SAR (RADAR) RICE FLOODING CLIMATE CHANGE

Economics of crop residue management

Vijesh Krishna Maxwell Mkondiwa (2023, [Artículo])

More than five billion metric tons of agricultural residues are produced annually worldwide. Despite having multiple uses and significant potential to augment crop and livestock production, a large share of crop residues is burned, especially in Asian countries. This unsustainable practice causes tremendous air pollution and health hazards while restricting soil nutrient recycling. In this review, we examine the economic rationale for unsustainable residue management. The sustainability of residue utilization is determined by several economic factors, such as local demand for and quantity of residue production, development and dissemination of technologies to absorb excess residue, and market and policy instruments to internalize the social costs of residue burning. The intervention strategy to ensure sustainable residue management depends on public awareness of the private and societal costs of open residue burning.

Crop Biomass Residue Burning Environmental Effects CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CROPS BIOMASS RESIDUES ENVIRONMENTAL IMPACT CLIMATE CHANGE SMALLHOLDERS TECHNOLOGY ADOPTION

Agroecology can promote climate change adaptation outcomes without compromising yield in smallholder systems

Sieglinde Snapp Yodit Kebede Eva Wollenberg (2023, [Artículo])

A critical question is whether agroecology can promote climate change mitigation and adaptation outcomes without compromising food security. We assessed the outcomes of smallholder agricultural systems and practices in low- and middle-income countries (LMICs) against 35 mitigation, adaptation, and yield indicators by reviewing 50 articles with 77 cases of agroecological treatments relative to a baseline of conventional practices. Crop yields were higher for 63% of cases reporting yields. Crop diversity, income diversity, net income, reduced income variability, nutrient regulation, and reduced pest infestation, indicators of adaptative capacity, were associated with 70% or more of cases. Limited information on climate change mitigation, such as greenhouse gas emissions and carbon sequestration impacts, was available. Overall, the evidence indicates that use of organic nutrient sources, diversifying systems with legumes and integrated pest management lead to climate change adaptation in multiple contexts. Landscape mosaics, biological control (e.g., enhancement of beneficial organisms) and field sanitation measures do not yet have sufficient evidence based on this review. Widespread adoption of agroecological practices and system transformations shows promise to contribute to climate change services and food security in LMICs. Gaps in adaptation and mitigation strategies and areas for policy and research interventions are finally discussed.

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CLIMATE CHANGE CROPS FOOD SUPPLY GAS EMISSIONS GREENHOUSE GASES FARMING SYSTEMS AGROECOLOGY FOOD SECURITY LESS FAVOURED AREAS SMALLHOLDERS YIELDS NUTRIENTS BIOLOGICAL PEST CONTROL CARBON SEQUESTRATION LEGUMES

¡La causa de México es la causa de América! : La unión de los liberales hispanoamericanos en estados unidos a través de la experiencia mexicana en el exilio, 1862-1867

Karina Grissel Mendoza Torres (2023, [Tesis de doctorado])

Es un estudio que refiere diversas formas de lucha política por parte de dos asociaciones civiles decimonónicas, conformadas a raíz de la acción bélica de las huestes francesas durante el periodo de 1862 - 1867 en el territorio estadunidense de California, Nevada, Oregon y Nueva York, a saber: las juntas patrióticas de California y el Club Mexicano de Nueva York. Ambos grupos propiciaron una serie de acciones colectivas tales como mítines, prensa de militante, recaudación monetaria y banquetes a favor del gobierno liberal de México y la ayuda pecuniaria del ejército mexicano. Se particulariza en la importancia de las celebraciones cívicas como el 16 de septiembre y el 05 de mayo, tanto en el territorio mexicano como en California, dónde se aprecia un discurso que legitimiza el nuevo orden político liberal, entre mezclado con el amor a la patria y sus próceres, al igual que la concepción de diversos conceptos como la libertad, la democracia y las instituciones republicanas. En este entramado político destaca la figura del ministro plenipotenciario de México, Matías Romero, parte fundamental y aglutinante tanto de las juntas patrióticas, El Club y el gobierno mexicano, representado en su persona. Se destaca su labor diplomática, de cabildeo político, pericia política y sutileza por saberse conducir entre los congresistas estadounidenses, los mexicanos y los hispanoamericanos que radicaban por tiempo determinado en territorio estadunidense. Resultado de la convivencia de funcionarios, diplomáticos e intelectuales hispanoamericanos como chilenos, peruanos, venezolanos, colombianos, argentinos y mexicanos, tanto en Nueva York como en Washington, se rescatará la tan anhelada Unión Americana y la defensa de los americanos en una época donde las hostilidades europeas, amenazaban a la prístinas Naciones quienes buscaban el establecimiento de repúblicas de corte liberal.

Liberalismo -- América Latina -- Historia Liberalismo -- Estados Unidos -- Historia Ideología Capitalismo Exiliados -- México -- Historia -- Siglo XIX Acciones Colectivas (Procedimiento civil) -- América Latina -- Siglo XIX América Latina -- Política y Gobierno -- Siglo XIX Estados Unidos -- Política y Gobierno -- Siglo XIX CIENCIAS SOCIALES HISTORIA HISTORIA

El antijudaísmo y el anticomunismo de José Vasconcelos en sus escritos: 1936-1940

CESAR CRUZ VENCES (2021, [Tesis de maestría])

"El objetivo general de esta investigación es identificar y analizar las causas por la cuales José Vasconcelos adopta una postura en contra de comunistas y judíos en sus escritos de 1936 a 1940, mediante el estudio de sus ideas políticas. Mientras que los objetivos específicos son: Demostrar que Vasconcelos fue un partidario de la democracia, tanto es sus escritos, como en su acción política y educativa, desde los inicios del Ateneo y el Maderismo (1909) hasta los comicios de 1929. Analizar el contexto histórico del cambio de sus ideas y postura política (1936-1940). Para saber cómo y por qué influyó en él dicho contexto histórico, para dicho cambio. Demostrar y explicar por qué las elecciones de 1929 fueron el parteaguas del cambio de postura política y religiosa de Vasconcelos, lo cual lo derivó en adoptar ideas antidemocráticas y estar en contra de judíos y comunistas. Explicar las razones del cambio de postura política que lo llevaron a adoptar ideas como el anticomunismo y el antijudaísmo."

Vasconcelos, José, 1881-1959 Judaísmo en México Movimientos anticomunistas -- México -- Historia -- Siglo XX México -- Política y gobierno -- Historia -- Siglo XX CIENCIAS SOCIALES HISTORIA HISTORIA

Contrabando y redes de negocios : Hispanoamérica en el comercio global, 1610-1814

Guillermina del Valle Pavón (2023, [Libro])

"Las colaboraciones que integran este libro colectivo profundizan en el análisis de algunos circuitos comerciales, que fueron claves en el juego de intercambios en Nueva España, Perú, las Filipinas, La Habana y Buenos Aires, en el arco temporal que se extiende de 1610 a 1814."

Hispanoamérica (Antiguo Régimen); Nueva España (Virreinato); Comercio; Comercio mundial; Comerciantes; Contrabando; Corrupción; Empresas; Mercantilismo; Monarquía hispánica; Mercaderes; Redes de negocios; Argentina; Estudios de caso; Siglos XVII-XIX; CIENCIAS SOCIALES HISTORIA HISTORIA POR ESPECIALIDADES HISTORIA POR ESPECIALIDADES

Farmers’ perspectives as determinants for adoption of conservation agriculture practices in Indo-Gangetic Plains of India

Ajay Kumar Mishra ML JAT (2022, [Artículo])

Understanding the farmer's perspective has traditionally been critical to influencing the adoption and out-scaling of CA-based climate-resilient practices. The objective of this study was to investigate the biophysical, socio-economic, and technical constraints in the adoption of CA by farmers in the Western- and Eastern-IGP, i.e., Karnal, Haryana, and Samastipur, Bihar, respectively. A pre-tested structured questionnaire was administered to 50 households practicing CA in Western- and Eastern-IGP. Smallholder farmers (<2 ha of landholding) in Karnal are 10% and Samastipur 66%. About 46% and 8% of households test soil periodically in Karnal and Samastipur, respectively. Results of PCA suggest economic profitability and soil health as core components from the farmer's motivational perspective in Karnal and Samastipur, respectively. Promotion and scaling up of CA technologies should be targeted per site-specific requirements, emphasizing biophysical resource availability, socio-economic constraints, and future impacts of such technology.

Smallholder Farmers Agents of Change Technology Diffusion Climate-Smart Practices CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA SMALLHOLDERS SOCIAL STRUCTURE IRRIGATION MANAGEMENT TECHNOLOGY CLIMATE-SMART AGRICULTURE CONSERVATION AGRICULTURE