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Modelación numérica de la circulación de la bahía de Todos Santos, B.C., México
Efraín Mateos Farfán Gabriela Colorado Ruiz (2017, [Documento de trabajo])
La modelación numérica fue la principal herramienta empleada en este trabajo. Para conocer la dinámica de la bahía de Todos Santos, se realizaron distintas corridas numéricas tanto del océano como de la atmósfera, con el modelo ROMS y WRF respectivamente. Para el caso de la modelación del océano, se incluyeron experimentos para conocer los efectos de baja frecuencia (viento sinóptico y Sistema de la Corriente de California) y altas frecuencias (mareas). En los experimentos realizados se encontró que las bajas frecuencias pueden generar variabilidad, en los campos de velocidad, de tres a cinco días a través de la propagación de una onda baroclínica que viaja desde la región de Punta Banda hasta la boca noroeste de la bahía. Para las altas frecuencias, se encontraron evidencias que la componente M2 de la marea es dominante en la región sur de la bahía, mientras que la brisa marina es importante en la región costera.
Hidrometeorología Modelación númerica CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA
Danny L. Fry (2014, [Artículo])
In Mediterranean environments in western North America, historic fire regimes in frequent-fire conifer forests are highly variable both temporally and spatially. This complexity influenced forest structure and spatial patterns, but some of this diversity has been lost due to anthropogenic disruption of ecosystem processes, including fire. Information from reference forest sites can help management efforts to restore forests conditions that may be more resilient to future changes in disturbance regimes and climate. In this study, we characterize tree spatial patterns using four-ha stem maps from four old-growth, Jeffrey pine-mixed conifer forests, two with active-fire regimes in northwestern Mexico and two that experienced fire exclusion in the southern Sierra Nevada. Most of the trees were in patches, averaging six to 11 trees per patch at 0.007 to 0.014 ha-1, and occupied 27-46% of the study areas. Average canopy gap sizes (0.04 ha) covering 11-20% of the area were not significantly different among sites. The putative main effects of fire exclusion were higher densities of single trees in smaller size classes, larger proportion of trees (≥56%) in large patches (≥10 trees), and decreases in spatial complexity. While a homogenization of forest structure has been a typical result from fire exclusion, some similarities in patch, single tree, and gap attributes were maintained at these sites. These within-stand descriptions provide spatially relevant benchmarks from which to manage for structural heterogeneity in frequent-fire forest types.
article, climate, controlled study, ecosystem fire history, forest structure, geographic distribution, geographic mapping, land use, mathematical computing, mathematical model, Mexico, spatial analysis, taiga, United States, comparative study, conife CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA
Daniel Arturo Cernas Ortiz (2023, [Artículo, Artículo])
This study´s objective was to examine empirical relationships between three dimensions of time perspective (future, present fatalistic, and past negative) and occupational self-efficacy. By surveying Mexican (n = 286) and U.S. (n = 272) respondents, we also tested the moderating role of culture. Regression analyses revealed that time perspective dimensions have significant associations with occupational self-efficacy, being future time perspective more potent than its past negative and present fatalistic counterparts. Moderation analyses indicated that none of the examined time perspective-self-efficacy relationships varied significantly between the U.S. and Mexico. Overall, this study suggests that relationships between time perspective and occupational self-efficacy vary according to different temporal dimensions, that future TP is key to develop occupational self-efficacy, and that cultural values may not exert a significant influence on the time perspective-occupational self-efficacy connection.
Perspectiva de tiempo autoeficacia diferencias culturales análisis de moderación CIENCIAS SOCIALES CIENCIAS SOCIALES Time perspective self-efficacy cultural differences moderation analysis
Análisis de la dinámica del monzón de Norteamérica usando modelos globales y regionales
SALVADOR CASTILLO LIÑAN (2021, [Tesis de maestría])
Maestro en Ciencias y Tecnología del Agua - Hidrometeorología) -- Instituto Mexicano de Tecnología del Agua. Coordinación de Desarrollo Profesional e Institucional. Subcoordinación de Posgrado.
El Monzón de Norteamérica (NAM) es un sistema atmosférico intraestacional causante de aproximadamente el 70% de las precipitaciones anuales en el noroeste de México y suroeste de Estados Unidos. Su estudio utilizando modelos numéricos es un reto debido a la compleja dinámica asociada a la abrupta orografía y al contraste térmico océano-continente que contribuyen a su desarrollo durante el verano. A pesar de que la gran mayoría de los modelos globales del experimento CMIP5 (Proyecto de Intercomparación de Modelos Acoplados), logran describir el periodo intraestacional de precipitaciones máximas sobre el dominio del NAM y reproducir su variabilidad espacial y temporal, se han identificado sesgos en las simulaciones con respecto a las observaciones y los datos de Reanálisis. Con el propósito de abordar estos sesgos, así como identificar y explicar el inicio-final del monzón, en este estudio se analiza el papel de los mecanismos entre la atmósfera, del continente y el océano, utilizando simulaciones numéricas regionales generadas con el modelo sueco RCA4 (Rossby Centre regional atmospheric model 4), el cual fue forzado con 10 modelos globales del CMIP5.
Monzón de Norteamérica Modelación numérica Precipitaciones INGENIERÍA Y TECNOLOGÍA
JORGE VICTOR PRADO HERNANDEZ PEDRO RIVERA RUIZ FELIPE BENJAMIN DE LEON MOJARRO MAURICIO CARRILLO GARCIA ANTONIO MARTINEZ RUIZ (2016, [Artículo])
La cuantificación de la erosión hídrica de los suelos en cuencas hidrográficas sirve para conocer el grado de su deterioro y para implementar medidas de conservación que minimicen la pérdida del suelo. Dada la carencia de la información para cuantificar con precisión aceptable la erosión en México, es necesario estudiar su estimación con la información disponible mediante metodologías validadas con información experimental. Por tal motivo, el objetivo de este estudio fue calibrar los modelos USLE (EUPS o Ecuación Universal de la Pérdida del Suelo, por sus siglas en inglés) y MUSLE (EUPS modificada) en la microcuenca El Malacate, perteneciente a la cuenca del Lago de Pátzcuaro en Michoacán, México con información experimental de 2013.
Erosión del suelo Conservación del suelo Modelación hidrológica INGENIERÍA Y TECNOLOGÍA
Value chain research and development: The quest for impact
Jason Donovan (2023, [Artículo])
Motivation: For decades, governments, donors, and practitioners have promoted market-based development approaches (MBDA), most recently in the form of value chain development (VCD), to spur economic growth and reduce poverty. Changes in approaches have been shaped by funders, practitioners and researchers in ways that are incompletely appreciated. Purpose: We address the following questions: (1) how have researchers and practitioners shaped discussions on MBDA?; and (2) how has research stimulated practice, and how has practice informed research? We hypothesize that stronger exchange between researchers and practitioners increases the relevance and impact of value chain research and development. Methods and approach: We adopt Downs' (1972) concept of issue-attention cycles, which posits that attention to a particular issue follows a pattern where, first, excitement builds over potential solutions; followed by disenchantment as the inherent complexity, trade-offs, and resources required to solve it become apparent; and consequently attention moves on to a new issue. We review the literature on MBDA to see how far this framing applies. Findings: We identify five cycles of approaches to market-based development over the last 40 or more years: (1) non-traditional agricultural exports; (2) small and medium enterprise development; (3) value chains with a globalization perspective; (4) value chains with an agri-business perspective; and (5) value chain development. The shaping and sequencing of these cycles reflect researchers' tendency to analyse and criticize MBDA, while providing limited guidance on workable improvements; practitioners' reluctance to engage in critical reflection on their programmes; and an institutional and funding environment that encourages new approaches. Policy implications: Future MBDA will benefit from stronger engagement between researchers, practitioners, and funders. Before shifting attention to new concepts and approaches, achievements and failures in previous cycles need to be scrutinized. Evidence-based practice should extend for the length of the issue-attention cycle; preferably it should arrest the cycling of attention. Funders can help by requiring grantees to critically reflect on past action, by providing “safe spaces” for sharing such reflections, and by engaging in joint learning with practitioners and researchers.
Agri-Food Value Chains Issue-Attention Cycles Market-Based Development Approaches CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA VALUE CHAINS PRIVATE SECTOR RURAL DEVELOPMENT SMALLHOLDERS
Jingyi Wang Chaonan Li Long Li Matthew Paul Reynolds Jizeng Jia Xinguo Mao Ruilian Jing (2023, [Artículo])
Association Analysis Elite Genetic Resources Map‐Based Clones Protein Phosphatase 2C CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA DROUGHT GENETIC RESOURCES PROTEINS WHEAT WILTING
Genomic regions associated with resistance to three rusts in CIMMYT wheat line “Mokue#1”
Naeela Qureshi Ravi Singh sridhar bhavani (2023, [Artículo])
Genetic Analysis Leaf Rust CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA GENETICS RUSTS QUANTITATIVE TRAIT LOCI MAPPING DISEASE RESISTANCE STRIPE RUST STEM RUST
Kindie Tesfaye Dereje Ademe Enyew Adgo (2023, [Artículo])
Spatiotemporal studies of the annual and seasonal climate variability and trend on an agroecological spatial scale for establishing a climate-resilient maize farming system have not yet been conducted in Ethiopia. The study was carried out in three major agroecological zones in northwest Ethiopia using climate data from 1987 to 2018. The coefficient of variation (CV), precipitation concertation index (PCI), and rainfall anomaly index (RAI) were used to analyze the variability of rainfall. The Mann-Kendall test and Sen’s slope estimator were also applied to estimate trends and slopes of changes in rainfall and temperature. High-significance warming trends in the maximum and minimum temperatures were shown in the highland and lowland agroecology zones, respectively. Rainfall has also demonstrated a maximum declining trend throughout the keremt season in the highland agroecology zone. However, rainfall distribution has become more unpredictable in the Bega and Belg seasons. Climate-resilient maize agronomic activities have been determined by analyzing the onset and cessation dates and the length of the growth period (LGP). The rainy season begins between May 8 and June 3 and finishes between October 26 and November 16. The length of the growth period (LGP) during the rainy season ranges from 94 to 229 days.
Climate Trends Spatiotemporal Analysis Agroecology Zone CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA AGROECOLOGY CLIMATE CLIMATE VARIABILITY MAIZE
Review of Nationally Determined Contributions (NCD) of China from the perspective of food systems
Tek Sapkota (2023, [Documento de trabajo])
China is the largest emitter of greenhouse gases (GHG) and one of the countries most affected by climate change. China's food systems are a major contributor to climate change: in 2018, China's food systems emitted 1.09 billion tons of carbondioxide equivalent (CO2eq) GHGs, accounting for 8.2% of total national GHG emissions and 2% of global emissions. According to the Third National Communication (TNC) Report, in 2010, GHG emissions from energy, industrial processes, agriculture, and waste accounted for 78.6%, 12.3%, 7.9%, and 1.2% of total emissions, respectively, (excluding emissions from land use, land-use change and forestry (LULUCF). Total GHG emissions from the waste sector in 2010 were 132 Mt CO2 eq, with municipal solid waste landfills accounting for 56 Mt. The average temperature in China has risen by 1.1°C over the last century (1908–2007), while nationally averaged precipitation amounts have increased significantly over the last 50 years. The sea level and sea surface temperature have risen by 90 mm and 0.9°C respectively in the last 30 years. A regional climate model predicted an annual mean temperature increase of 1.3–2.1°C by 2020 (2.3–3.3°C by 2050), while another model predicted a 1–1.6°C temperature increase and a 3.3–3.7 percent increase in precipitation between 2011 and 2020, depending on the emissions scenario. By 2030, sea level rise along coastal areas could be 0.01–0.16 meters, increasing the likelihood of flooding and intensified storm surges and causing the degradation of wetlands, mangroves, and coral reefs. Addressing climate change is a common human cause, and China places a high value on combating climate change. Climate change has been incorporated into national economic and social development plans, with equal emphasis on mitigation and adaptation to climate change, including an updated Nationally Determined Contribution (NDC) in 2021. The following overarching targets are included in China's updated NDC: • Peaking carbon dioxide emissions “before 2030” and achieving carbon neutrality before 2060. • Lowering carbon intensity by “over 65%” by 2030 from the 2005 level. • Increasing forest stock volume by around 6 billion cubic meters in 2030 from the 2005 level. The targets have come from several commitments made at various events, while China has explained very well the process adopted to produce its third national communication report. An examination of China's NDC reveals that it has failed to establish quantifiable and measurable targets in the agricultural sectors. According to the analysis of the breakdown of food systems and their inclusion in the NDC, the majority of food system activities are poorly mentioned. China's interventions or ambitions in this sector have received very little attention. The adaptation component is mentioned in the NDC, but is not found to be sector-specific or comprehensive. A few studies have rated the Chinese NDC as insufficient, one of the reasons being its failure to list the breakdown of each sector's clear pathway to achieving its goals. China's NDC lacks quantified data on food system sub-sectors. Climate Action Trackers' "Insufficient" rating indicates that China's domestic target for 2030 requires significant improvements to be consistent with the Paris Agreement's target of 1.5°C temperature limit. Some efforts are being made: for example, scientists from the Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences (IEDA-CAAS) have developed methods for calculating GHG emissions from livestock and poultry farmers that have been published as an industrial standard by the Ministry of Agriculture and Rural Affairs, PRC (Prof Hongmin Dong, personal communication) but this still needs to be consolidated and linked to China’s NDC. The updated Nationally Determined Contributions fall short of quantifiable targets in agriculture and food systems as a whole, necessitating clear pathways. China's NDC is found to be heavily focused on a few sectors, including energy, transportation, and urban-rural development. The agricultural sectors' and food systems' targets are vague, and China's agrifood system has a large carbon footprint. As a result, China should focus on managing the food system (production, processing, transportation, and food waste management) to reduce carbon emissions. Furthermore, China should take additional measures to make its climate actions more comprehensive, quantifiable, and measurable, such as setting ambitious and clear targets for the agriculture sector, including activity-specific GHG-reduction pathways; prioritizing food waste and loss reduction and management; promoting sustainable livestock production and low carbon diets; reducing chemical pollution; minimizing the use of fossil fuel in the agri-system and focusing on developing green jobs, technological advancement and promoting climate-smart agriculture; promoting indigenous practices and locally led adaptation; restoring degraded agricultural soils and enhancing cooperation and private partnership. China should also prepare detailed NDC implementation plans including actions and the GHG reduction from conditional targets.
CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA GREENHOUSE GAS EMISSIONS CLIMATE CHANGE FOOD SYSTEMS LAND USE CHANGE AGRICULTURE POLICIES DATA ANALYSIS FOOD WASTES