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803 resultados encontrados para: AUTOR: Sánchez, A.
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1.
- Artículo con arbitraje
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Management strategies, silvopastoral practices and socioecological drivers in traditional livestock systems in tropical dry forests: an integrated analysis
Sánchez Romero, Rosa (autora) ; Balvanera, Patricia (autora) ; Castillo Álvarez, Alicia (autora) ; Mora Ardila, Francisco (autor) ; García Barrios, Luis Enrique (autor) ; González Esquivel, Carlos Ernesto (autor) ;
Disponible en línea
Contenido en: Forest Ecology and Management Volumen 479, artículo número 118506 (January 2021), páginas 1-10 ISSN: 0378-1127
Nota: Solicítelo con su bibliotecario/a
Resumen en: Inglés |
Resumen en inglés

Understanding traditional livestock management is essential in the design of more sustainable systems, given the forest loss associated to the growing demand for meat. In Latin America, where extensive livestock production is increasing, along with tropical dry forest (TDF) transformation, the role of small holders is critical for designing more sustainable management practices. This study is an integrated socioecological analysis of traditional livestock systems in a region with TDF in Mexico. The objectives were to: a) characterise the historical development and current state of livestock systems and silvopastoral practices, b) define the management strategies and their impacts on forests, and c) identify the regional and local socioecological drivers that influence decision- making processes in livestock and forest management. In-depth interviews were carried out to 32 cattle farmers and analysed using a qualitative-interpretative approach which included multivariate and narrative analyses. Three historical stages (colonization, promotion of livestock and forest conservation) had a strong impact in the development and current state of livestock systems. Access to natural and economic resources and proportion of plant cover (grassland/forest) were essential in defining four groups of management strategies.

The main regional drivers favouring or restricting production include climate, native vegetation, markets and public policies; at the local scale, socioecological factors, such as water availability, native vegetation, economic assets, local knowledge and their interactions determine heterogeneity in management strategies, decision-making processes and their impacts on forests. Adaptive management of livestock and forests in a context of limited economic resources has allowed the conservation of forest areas and the use of silvopastoral practices with local tree species. The integrated socio-ecological approach and the use of mixed methods allowed a better understanding of drivers and their interrelationships, the local knowledge, objectives and perceptions of farmers in the decision-making processes regarding livestock and forest management. Perspectives of farmers on resource use can contribute to the design of more effective and inclusive policies for sustainable livestock systems in the dry tropics.


2.
Tesis - Maestría
Resumen en español

Objetivo. Determinar la tasa de positividad a B. pertussis y los factores clínicos y epidemiológicos asociados a dicha positividad. Métodos. Se realizó un estudio transversal, del 1 de marzo al 25 de octubre de 2019, en el que se incluyeron todos/as los/as niños/as menores de cinco años de edad, que fueron admitidos al servicio de urgencias pediátricas del Hospital de Las Culturas, de San Cristóbal de Las Casas, Chiapas, y que presentaban signos y síntomas compatibles con tosferina y/o síndrome coqueluchoide (n=38). A los padres de las y los niños incluidos en el estudio, se les entrevistó para recopilar información demográfica, epidemiológica y clínica de las y los niños, a los cuales se les tomaron dos muestras de exudados nasofaríngeos para realizar el diagnóstico confirmatorio por cultivo, MALDI-TOF y PCR-TR. De manera adicional, se tomaron datos sanguíneos, de la fórmula blanca, del expediente clínico de las y los niños estudiados, con el fin de utilizarlos para analizar la positividad de infección mediante un predictor clínico que incluyó las concentraciones de leucocitos ≥ a 21.6 x103 /μl y linfocitos a ≥11.5 /μl, analizando la asociación con las variables en estudio. Resultados: Se evidenció la presencia de casos de tosferina: la tasa de positividad por cultivo fue de 5.4%; por PCR-TR, 16.12% y, por el predictor clínico, 36.66%. No se encontró ninguna asociación estadísticamente significativa entre la positividad a tosferina y las variables analizadas. También se encontró una alta proporción (78.9%) de niños/as que no tenían su esquema completo de vacunación contra esta enfermedad. Conclusiones: Es necesario mejorar la prevención y el diagnóstico de casos de tosferina por parte de los servicios de salud de la región, mediante la capacitación y sensibilización al personal, así como dotarlo de los equipos e insumos para la vacunación y detección de casos de esta enfermedad.

Índice

Dedicatoria y Agradecimientos
Resumen
Introducción
Estado del Arte
Generalidades de la tosferina
Vacunación contra la tosferina
Vacunación contra la tosferina en México
Antecedentes y epidemiología de la Tosferina en México
Características biológicas de Bordetella pertussis
Divergencia antigénica entre cepas vacunales y circulantes
Patogenia
Características clínicas de la enfermedad
Diagnóstico
Tratamiento
Justificación
Pregunta de Investigación
Hipótesis
Objetivos
Objetivo General:
Objetivo Específico:
Metodología
Lugar y población de estudio
Criterios de inclusión
Criterios de exclusión
Procedimiento de recolección de datos
Toma de muestra de Exudado Nasofaríngeo (ExNf)
Diagnóstico microbiológico
Residuos peligrosos biológicos infecciosos (RPBI)
Resultados
Discusión
Conclusiones
Anexos
Aspectos Éticos
Literatura Citada
Cuadros y Figura


3.
Artículo
Aprovechamiento forestal y diversidad arbórea en seis ejidos de Quintana Roo
Aguirre Cortés, Efraín (autor) ; Escalona Segura, Griselda (autora) ; Macario Mendoza, Pedro A. (autor) ; León Cortés, Jorge Leonel (autor) ; Sánchez Pérez, Luis Candelario (autor) ; Schmook, Birgit Inge (autora) ;
Disponible en línea
Contenido en: Revista Mexicana de Ciencias Forestales Volumen 11, número 60 (julio-agosto 2020), p. 78-96 ISSN: 2007-1132
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Resumen en: Español | Inglés |
Resumen en español

El aprovechamiento forestal en el sureste de México se realiza desde la civilización Maya mediante usos tradicionales, concesiones forestales hasta la propiedad comunal. Actualmente, la mitad de los ejidos de Quintana Roo están enfocados en el aprovechamiento forestal maderable, principalmente en selvas medianas subperennifolias, el tipo de vegetación con mayor cobertura. El objetivo de este trabajo consistió en determinar la diversidad arbórea en 14 selvas del sur de la Península de Yucatán, con edades, prácticas de manejo y conservación distintas: seis en ejidos forestales del estado de Quintana Roo y ocho en otros sitios. Se analizaron 10 parcelas de 500 m² por sitio, en las que las especies arbóreas fueron identificadas taxonómicamente y se midió el diámetro a la altura del pecho en ejemplares desde los 7.5 cm hasta 1.30 m sobre el suelo. Se determinó una riqueza de 156 especies de árboles con abundancia, dominancia e importancia relativas contrastante entre sitios. Se realizó, para los 14 sitios, un análisis de similitud de Bray Curtis, que se conformó por tres grupos: el primero por un sitio en la Reserva de la Biósfera de Calakmul sin uso, el segundo por seis sin uso, desde 7 hasta 50 años y el tercero por seis ejidos forestales. La riqueza, abundancia y similitud entre ellos probablemente se asocian a la ubicación geográfica y a la edad de recuperación tanto de disturbios antrópicos como naturales. Se sugiere incorporar dichas características ecológicas como indicadores en los planes de aprovechamiento forestal, acotados ambiental y socioeconómicamente.

Resumen en inglés

Timber forestry in southern Mexico is a common practice since Mayan civilization, through traditional uses, forest concessions and up to communal land tenure. Currently, half of Quintana Roo ´s ejidos are focused on timber forestry use, mainly on middle evergreen subtropical forests, the greatest kind of vegetation cover. This aim of this study was to determine forestry diversity in 14 forests in the south of Yucatán Peninsula with different age, management and conservation practices: six forestry sites in Quintana Roo and eight in other places. 10 plots of 500 m² per site were analyzed, in which the tree species were taxonomically identified and the diameter at height was measured in specimens from 7.5 cm to 1.30 m above the ground. A richness of 156 tree species with relative abundance, dominance and importance was determined, contrasting between sites. A similarity analysis was carried out for the 14 sites by the Bray Curtis method, which was made up of three groups: the first by site of the Calakmul Biosphere Reserve without use, the second by six sites without use, from 7 to 50 years old and the third by six forest ejidos. The richness, abundance and similarity between them are probably associated with the geographical location and the age of recovery from anthropogenic and natural disturbances. It is suggested to incorporate these ecological characteristics as indicators in the forest use plans, limited environmentally and socioeconomically.


4.
Artículo
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Resumen en: Inglés |
Resumen en inglés

This study was aimed at evaluating thein vitroeffect of the edible mushroom (EM) Pleurotus eryngiiagainst the eggs and larvae (L3) of Haemonchus contortus. The evaluation included acetone (AE) and hydroalcoholic (HA) extracts of the following strains: ECS-1138, ECS-1156, ECS-1255, ECS-1258, ECS-1261, ECS-1282, and ECS-1292. The HA extract of the ECS-1255 strain showed thehighest effect on mortality rates of L3 (18.83%) at 20 μg/mL. After subjecting this HA extract to a normal phase chromatography column, five fractions were obtained; fraction F5 (100% MeOH) was the most effective against eggs, with hatching inhibition percentages of 88.77 and 91.87% at 20 and 40 mg/mL, respectively. Gas chromatography-mass spectrometry (GC-MS) subjected this fraction to an acetylation reaction to determine the content of the secondary metabolites. The GC-MSanalysis showed that the F5 fraction was composed of trehalose CAS: 6138-23-4, polyols (L-iditol CAS: 488-45-9, galactitol CAS:608-66-2, D-mannitol CAS: 69-65-8, D-glucitol CAS: 50-70-4, and myoinositol CAS: 87-89-8), adipic acid CAS: 124-04-9, stearic acid CAS: 57-11-4, squalene CAS: 111-02-4, and β-sitosterol CAS: 83-46-5.


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6.
Artículo
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Resumen en: Inglés |
Resumen en inglés

Natural Protected Areas (NPAs) are consider adequate tools for biodiversity conservation. Currently in Mexico there are 182 federal NPAs classified according to their management objectives. Chiapas is the Mexican state with the highest number of decreed NPAs and also allocates one of the largest territorial extensions for its protection. Unlike other taxa, and despite their proven ability to respond to ecosystem changes, the study of dung beetles within Mexican NPAs has been underestimated, as they are not considered as a priority group within their management and conservation programs. Based on the review of information available in publications and database on dung beetles, a list of 112 species and seven subspecies recorded in 16 of the 19 federal NPAs established in Chiapas is presented.

The species recorded by each NPA show a significant correlation with the number of publications, but a low percentage of them correspond to studies with systematic samplings and most of the species reported in several of the NPAs come from sporadic records, which prevents the study of several basic and applied aspects of dung beetles in the region. Therefore, studies that extensively analyze the communities of arthropod groups, such as the Scarabaeinae, are necessary to understand their response to changes in the ecosystem at local and regional scale. It is advisable that these insects be included in the previous justifying studies for the designation or establishment of NPAs and, in turn, considered in the biological monitoring programs of these areas for their capacity as a bioindicator group.


7.
- Artículo con arbitraje
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Resumen en: Inglés |
Resumen en inglés

While [CO2] effects on growth and secondary chemistry are well characterized for annual plant species, little is known about perennials. Among perennials, production of Coffea arabica and C. canephora (robusta) have enormous economic importance worldwide. Three Arabica cultivars (Bourbon, Catimor, Typica) and robusta coffee were grown from germination to ca. 12 months at four CO2 concentrations: 300, 400, 500 or 600 ppm. There were significant increases in all leaf area and biomass markers in response to [CO2] with significant [CO2] by taxa differences beginning at 122–124 days after sowing (DAS). At 366–368 DAS, CO2 by cultivar variation in growth and biomass response among Arabica cultivars was not significant; however, significant trends in leaf area, branch number and total above-ground biomass were observed between Arabica and robusta. For caffeine concentration, there were significant differences in [CO2] response between Arabica and robusta. A reduction in caffeine in coffee leaves and seeds might result in decreased ability against deterrence, and consequently, an increase in pest pressure. We suggest that the interspecific differences observed (robusta vs. Arabica) may be due to differences in ploidy level (2n = 22 vs. 2n = 4x = 44). Differential quantitative and qualitative responses during early growth and development of Arabica and robusta may have already occurred with recent [CO2] increases, and such differences may be exacerbated, with production and quality consequences, as [CO2] continues to increase.


8.
Artículo
Moon light and the activity patterns of baird’s tapir in the Calakmul region, Southern Mexico
Sánchez Pinzón, Khiavett Guadalupe (autora) ; Reyna Hurtado, Rafael Ángel (autor) ; Meyer, Ninon France Victoire (autora) ;
Contenido en: Therya Vol. 11, no. 1 (2020), p. 137-142 ISSN: 2007-3364
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Resumen en: Español | Inglés |
Resumen en español

El tapir de Baird (Tapirella bairdii) es una especie amenazada en toda su área de distribución, sin embargo, muchos aspectos de su biología y ecología han sido poco estudiados, debido a su comportamiento evasivo y a sus bajas densidades poblacionales. El objetivo de este estudio fue evaluar los patrones de actividad de T. bairdii en relación con las fases lunares en dos sitios con diferente grado de perturbación humana: la Reserva de la Biosfera de Calakmul (RBC) y el Ejido Nuevo Becal (NB). Se monitorearon 20 cuerpos de agua durante18 meses mediante el método de foto-trampeo. Se determinó la tasa de captura (TC) y se registraron las fases lunares correspondientes para ambos sitios. La TC de T. bairdii tapir fue de 0.054 en NB y de 0.029 en la RBC. T. bairdii fue más activo en el periodo nocturno-crepuscular. En general, T.bairdii. mostro una actividad importante durante las fases de oscuridad, pero estas diferencias no fueron significativas estadísticamente. Sin embargo, se encontró una tendencia de los tapires a moverse activamente en las noches y en las horas más obscuras en NB que en RBC. La preferencia aparente por las noches más obscuras en NB podría ser evidencia de la respuesta por parte de los tapires a la perturbación causada por actividades humanas en ese sitio, mostrando un cambio en su comportamiento evitando salir en periodos de abundante luz en sitios perturbados. Sin embargo, se requiere de mayor investigación para corroborar esta posibilidad.

Resumen en inglés

The Baird’s tapir (Tapirella bairdii) is an endangered species throughout its distribution area, however many aspects of its biology and ecology have been poorly studied, due to its evasive behavior and low densities. The goal of this study was to evaluate the activity patterns of T. bairdii, a large ungulate species from the Neotropics, in relation to moon phases in two sites with different degree of human perturbation: the Calakmul Biosphere Reserve (CBR) and the Nuevo Becal (NB) community. We monitored twenty waterbodies in each site for 18 months using camera traps. The photographic capture rate (CR) and the corresponding moon phases for both sites were recorded. The CR of T. bairdii was 0.054 in NB and 0.029 in CBR. T. bairdii was more active at night and dawn-twilight periods. In general, T. bairdii showed major activity during the dark moon phases but the differences with the light phases were not statistically significant. However, we found a trend of tapirs to be more active in dark nights and in the darkest hours in NB than CBR. The apparent preferences for dark nights in NB could be caused by the perturbation caused by human activities at site, which may have influenced the behavior of the tapir that avoid moving out in periods of abundant light in disturbed sites. More research is needed to confirm this finding.


9.
Artículo
*Solicítelo con su bibliotecario/a
Population status, connectivity, and conservation action for the endangered Baird's tapir
Schank, Cody J. (autor) ; Cove, Michael V. (autor) ; Arima, Eugenio Y. (autor) ; Brandt, Laroy S. E. (autor) ; Brenes Mora, Esteban (autor) ; Carver, Andrew (autor) ; Diaz Pulido, Angelica (autora) ; Estrada, Nereyda (autora) ; Foster, Rebecca J. (autora) ; Godínez Gómez, Oscar (autor) ; Harmsen, Bart J. (autor) ; Jordan, Christopher A. (autor) ; Keitt, Timothy H. (autor) ; Kelly, Marcella J. (autora) ; Sáenz Méndez, Joel (autor) ; Mendoza Ramírez, Eduardo (autor) ; Meyer, Ninon France Victoire (autora) ; Pozo Montuy, Gilberto (autor) ; Naranjo Piñera, Eduardo Jorge (autor) (1963-) ; Nielsen, Clayton K. (autor) ; O´Farril Cruz, Elsa Georgina (autora) ; Reyna Hurtado, Rafael Ángel (autor) ; Rivero Hernández, Crysia Marina (autora) ; Carvajal Sánchez, José Pablo (autor) ; Singleton, Maggie (autora) ; Torre, J. Antonio de la (autor) ; Wood, Margot A. (autora) ; Young, Kenneth R. (autor) ; Miller, Jennifer A. (autora) ;
Disponible en línea
Contenido en: Biological Conservation Volumen 245, número 108501 (May 2020), p. 1-12 ISSN: 0006-3207
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Resumen en: Inglés |
Resumen en inglés

Although many large mammals currently face significant threats that could lead to their extinction, resources for conservation are often scarce, resulting in the need to develop efficient plans to prioritize conservation actions. We combined several methods in spatial ecology to identify the distribution of the endangered Baird's tapir across its range from southern Mexico to northern Colombia. Twenty-eight habitat patches covering 23% of the study area were identified, harboring potentially 62% or more of the total population for this flagship species. Roughly half of the total area is under some form of protection, while most of the remaining habitat (~70%) occurs in indigenous/local communities. The network with maximum connectivity created from these patches contains at least one complete break (in Mexico between Selva El Ocote and Selva Lacandona) even when considering the most generous dispersal scenario. The connectivity analysis also highlighted a probable break at the Panama Canal and high habitat fragmentation in Honduras. In light of these findings, we recommend the following actions to facilitate the conservation of Baird's tapir: 1) protect existing habitat by strengthening enforcement in areas already under protection, 2) work with indigenous territories to preserve and enforce their land rights, and help local communities maintain traditional practices; 3) re-establish connections between habitat patches that will allow for connectivity across the species' distribution; 4) conduct additional noninvasive surveys in patches with little or no species data; and 5) collect more telemetry and genetic data on the species to estimate home range size, dispersal capabilities, and meta-population structure.


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