Abstract In Mexico, shade-grown coffee agroecosystems form part of the agroforestry landscape and provide shelter for a wide range of biological diversity. However, they are subject to transformation processes derived from the needs of producers and market demands, which affects the configuration of the agroecosystem. The present study aimed to quantify the transformations of land use cover related to coffee plantations in the upper La Antigua river basin, that has occurred over a period of 24 years. The dynamics of change in the coverage of land use and vegetation was analyzed, by generating cartography with the supervised classification technique of the LANDSAT images (TM, ETM, and OLI) of the years of 1993, 2003 and 2017 and the analysis of the factors that have promoted the changes that determine the current configuration of the agroforestry landscape, based on interviews with key stakeholders in the region. The results show that the transformation of the agroforestry systems in shade-grown coffee plantations is caused by land use changes and the government programs implemented in the region. Coffee growing represents one of the main sources of income in the Ecological Corridor of the Sierra Madre Oriental of the state of Veracruz, which requires the development of strategies that guarantee the maintenance and sustainability of this economic activity in the zone to avoid the potential impacts to the local development of the communities, as well as the affectation or loss of the natural ecosystems remaining in the region.

Resumen En México, los cafetales bajo sombra constituyen parte del paisaje agroforestal y representan el refugio de una alta diversidad biológica. Sin embargo, están sujetos a procesos de transformación derivados de las necesidades de los productores y las demandas del mercado, lo que afecta la configuración del agroecosistema. Este trabajo tuvo como objetivo cuantificar las transformaciones de los usos de suelo relacionados con los cafetales en la cuenca alta de La Antigua, durante un periodo de 24 años. Se analizó la dinámica de cambio en las coberturas de uso del suelo y vegetación, mediante la generación de cartografía con la técnica de clasificación supervisada de las imágenes LANDSAT (TM, ETM y OLI) de los años de 1993, 2003 y 2017 y se analizaron los catalizadores de los cambios que determinan la configuración actual del paisaje agroforestal con base en entrevistas a actores clave de la región. Los resultados muestran que la transformación de los sistemas agroforestales de los cafetales bajo sombra se debe a los cambios de uso del suelo y los programas gubernamentales implementados en la zona. La cafeticultura representa una de las principales fuentes de ingreso en la región del Corredor Ecológico de la Sierra Madre Oriental del estado de Veracruz, por lo que se requiere el desarrollo de estrategias que garanticen el mantenimiento y la sostenibilidad de esta actividad económica en la zona para evitar los impactos potenciales al desarrollo local de las comunidades, así como la afectación o pérdida de los ecosistemas naturales remanentes en la región.

Abstract: We derive a new comprehensive evolution equation to describe the nonlinear propagation of high power optical pulses through photonic nanowires. Our basic formulation part from the vectorial form of Maxwell's equations and take into account the effect of the complete strong dispersion implicit in the propagation constant β of the propagating mode inside the spectral body of the optical pulses. Applying our new nonlinear propagation equation in air-silica photonic nanowires, we show evidence of additional effects that perturb the supercontinuum, reducing its extreme long-wavelength edge and making it narrower.

Resumo O congelamento usando campos magnéticos oscilantes (OMF) foi desenvolvido e é comercializado para superar as desvantagens que normalmente ocorrem no congelamento convencional, que afeta a firmeza, a cor, o sabor e a perda por gotejamento em alimentos congelados e descongelados. A fim de verificar as vantagens acima mencionadas, avaliamos o efeito do congelamento usando o OMF em cubos de manga (Mangifera indica L. cv. 'Kent'). Os cubos foram congelados a -30 °C durante 35 min com OMF ajustado a 0, 30%, 50%, 75% e 100% e, depois, imediatamente descongelados à temperatura ambiente (25 °C) durante 70 min. Cubos de manga descongelados mostraram quebra na parede celular, presumivelmente devido à formação de cristais de gelo. Da mesma forma, os cubos congelados e descongelados apresentaram menor firmeza (p < 0,05) que os cubos de manga fresca (com ambos os cubos provenientes do mesmo espécime), conforme determinado pelo texturômetro e pela avaliação sensorial. A perda por gotejamento variou de 2,45% a 4,15% em manga descongelada. Congelar usando OMF com um congelador do tipo Cells Alive System (CAS) causou mudanças negativas na manga descongelada, principalmente uma diminuição na firmeza, com resultados semelhantes aos relatados em outros estudos usando o congelamento convencional.

Abstract Freezing using oscillating magnetic fields (OMF), was developed and is marketed to overcome drawbacks that normally occur in conventional freezing, which affect firmness, colour, taste, and drip loss in frozen-thawed foods. In order to verify the aforementioned advantages, the effect of freezing using OMF on cubes of mango (Mangifera indica L. cv. ‘Kent’) was evaluated. The cubes were frozen at -30 °C for 35 min with OMF set at 0, 30%, 50%, 75% and 100%, and then immediately thawed at room temperature (25 °C) for 70 min. The frozen-thawed mango cubes showed cell wall breakage, presumably due to the formation of ice crystals. Likewise, the frozen-thawed cubes were less firm (p < 0.05) than fresh mango cubes (with both cubes having come from the same specimen), as determined using a texturometer and sensory evaluation. Drip loss ranged from 2.45% to 4.15% in the frozen-thawed mango. Freezing using OMF with a Cells Alive System (CAS) freezer caused negative changes to the thawed mango, mainly a decrease in firmness, with results similar to those reported elsewhere using conventional freezing.

Diptera is one of the major groups of insects that contribute to organic matter decomposition, including several species of Calliphoridae and Chrysomya rufifacies (Macquart) has been recorded as the principal species that colonizes carrion in the Comarca Lagunera of Coahuila. An experiment was conducted during spring and summer of 2010 in order to study the larval development as well as to know the complete life cycle of C. rufifacies. It was divided in two stages at Universidad Autónoma Agraria Antonio Narro-Unidad Laguna facilities. In the first stage 4 chicken carcasses were used, whereas in the second, 4 pig heads were used as necrotraps. Pregnant females of C. rufifacies were collected, which were reared to obtained eggs and study the biological cycle until adult emergence. Five larvae specimens were measured every four hours, recording its length and diameter and instar changes. Temperature in the breeding room was recorded to calculate degree days accumulated (DDA) for this species. During spring C. rufifacies accumulated 192.57 DD while in the summer it accumulated 190.69 DD, these amounts were necessary to complete the cycle from the egg to adult emergence. During spring and summer C. rufifacies pupated in 96 hours after egg hatching. The results of this study contribute to knowledge of C. rufifacies biology as well as increasing the sarcosaprophagous fauna database of the Comarca Lagunera, especially in Torreon, Coahuila

Los dípteros conforman uno de los principales grupos de insectos descomponedores de materia orgánica, destacando varias especies de la familia Calliphoridae y Cihrysomya rufifacies (Macquart) ha sido consignada como la principal especie califórida colonizadora de carroña en la Comarca Lagunera de Coahuila. Durante primavera y verano del año 2010 se estableció un experimento para estudiar el desarrollo larval así como conocer el ciclo de vida de C. rufifacies. Éste estuvo dividido en dos etapas en las instalaciones de la Universidad Autónoma Agraria Antonio Narro-Unidad Laguna. En la primera etapa se usaron cuatro carcasas de pollo, mientras que en la segunda fueron usadas cuatro cabezas de cerdo como necrotrampas. Se colectaron hembras grávidas de C. rufifacies, las cuales fueron criadas y alimentadas para obtener huevos y estudiar el ciclo de desarrollo hasta adulto. Se midieron cinco larvas cada cuatro horas, tanto en longitud como en diámetro, además de registrar el cambio de estadío en cada medición. Se registró la temperatura del cuarto de cría diariamente y se calcularon las Unidades Calor Acumuladas (UCA) necesarias para completar el ciclo de C. rufifacies. En primavera C. rufifacies necesitó 192. 57 UC y en verano 190.69 UC para pasar de huevo hasta la emergencia del adulto. En ambas etapas la larva de esta especie pupó a las 96 horas después de la eclosión (HDDE). Con los resultados de este trabajo se contribuye al conocimiento de la biología de C. rufifacies así como también se incrementa la base de datos sobre fauna sarosaprófaga de la Comarca Lagunera y en especial de Torreón, Coahuila.