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Análisis funcional de la red trófica de Bahía Magdalena Baja California Sur, México

Functional analysis of the food web of Bahia Magdalena, Baja California Sur, Mexico

VICTOR HUGO CRUZ ESCALONA MARIA VERONICA MORALES ZARATE Andrés Felipe Navia PABLO DEL MONTE LUNA (2013)

"El objetivo del presente estudio fue desarrollar un modelo trófico (ECOPATH con ECOSIM) para caracterizar la estructura y función de la trama alimentaria de Bahía Magdalena. El modelo consta de 24 grupos funcionales, siendo dominado por grupos de niveles tróficos secundarios y terciarios, que generan un tercio de los flujos de biomasa total. Los flujos totales del sistema y la eficiencia de transferencia promedio entre niveles tróficos, encajan bien en el rango reportado para otros ecosistemas costeros tropicales del mundo. Una fracción alta de los flujos totales se destina para el mantenimiento de la estructura de la red trófica. El índice de conectancia (IC) fue igual a 0,2, esto significa que sólo hay 20% de las conexiones totales posibles en la trama alimentaria. Una jerarquización de los diversos componentes del sistema en términos de su contribución a la función del sistema reveló que los productores primarios bentónicos y los detritos contribuyen 53% al total de la ascendencia. La idea de un control de la energía de arriba hacia abajo (a través de los principales depredadores) es consistente con otros hallazgos, dicho resultado sugiere que las especies de nivel trófico superior afectan negativamente a otros componentes del ecosistema. Se sugiere emplear el modelo en el corto plazo, para realizar aproximaciones exploratorias que pongan a prueba hipótesis relacionadas con los mecanismos bióticos y abióticos que ocasionen cambios en la estructura y función de la red trófica a través del tiempo, y por tanto contribuyan a entender como la estructura de la trama trófica puede contribuir a la resiliencia de las comunidades biológicas marinas."

"In the present study we developed a trophic model (ECOPATH with ECOSIM), to describe the structure and functioning of Bahía Magdalena estuarine ecosystem. The model, constituted by 24 functional groups, indicates that one third of the total ecosystem biomass is produced by secondary and tertiary trophic levels. The magnitude of total flows in the system and the transfer efficiency among trophic levels, are similar to those observed in other tropical systems around the world. A large proportion of the total flows are directed to the maintenance of the trophic web structure. The value of the connectance index (CI) was 0.2, meaning that there is only 20% of realized connections within the web. Benthic primary producers contribute with 53% of the total ascendency. We believe that the energy control in this particular ecosystem is top-down type (through the main predators), suggesting that high-trophic level species negatively affect other groups in the system. This trophic model can be used for exploring different hypothesis concerning the biotic and abiotic mechanisms that modify the structure and functioning of the Bahía Magdalena ecosystem, with the ultimate goal of understanding how this attributes determine the resilience of marine communities."

Article

control top-down, flujos tróficos, ECOPATH, atributos ecológicos top-down control, trophic fluxes, ecological attributes BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA ANIMAL (ZOOLOGÍA) ECOLOGÍA ANIMAL

Efectos a nivel ecosistema de la pesquería de pelágicos menores en el Golfo de California

ECOSYSTEM-LEVEL EFFECTS OF THE SMALL PELAGICS FISHERY IN THE GULF OF CALIFORNIA

PABLO DEL MONTE LUNA SALVADOR EMILIO LLUCH COTA CHRISTIAN JAVIER SALVADEO DANIEL BERNARDO LLUCH COTA (2011)

"Existe documentación científica suficiente como para suponer que la pesquería de pelágicos menores en el Golfo de California no afecta significativamente el hábitat ni las relaciones funcionales entre las especies que conforman el ecosistema pelágico del cual depende. Tampoco hay información que indique interferencia entre las operaciones de la pesquería de pelágicos menores y especies amenazadas o en peligro de extinción, específicamente la vaquita y la totoaba. Adicionalmente, bajo el sistema actual de manejo, esta pesquería no sólo ha logrado recuperarse exitosamente en dos ocasiones durante los últimos 30 años sino que también cuenta con la plataforma logística y administrativa necesarias para asegurar un aprovechamiento racional de las especies objetivo y la productividad de la propia actividad en el largo plazo, en congruencia con los estándares internacionales de pesca responsable y enfoque precautorio."

"Documentary scientific evidence supports the notion that the small pelagics fishery in the Gulf of California does not measurably affect the physical habitat or the functional relationships between the species comprising the pelagic ecosystem. Also, there is little information that suggests any negative effects of the small pelagic fishery operations on critically endangered, endemic species, i.e., vaquita and totoaba. Under the current management regime, small pelagics fishery in the Gulf of California has recovered twice from collapses during the last 30 years. Although the small pelagics abundance varies greatly, the long-term productivity of the target species and the structure and function of the pelagic ecosystem are not compromised because the fishery relies on a suitable logistic and administrative platform, which is consistent with international standards for responsible fisheries, precautionary approach and ecosystem-based fisheries management principles."

Article

Cambio climático, colapso, modelación ecológica, , recuperación, relaciones tróficas, sardina monterrey. Climate change, collapse, ecological modeling, Pacific sardine, recovery, trophic relationships. BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA ANIMAL (ZOOLOGÍA) ZOOLOGÍA MARINA

Trophic ecology of the exotic Lerma livebearer Poeciliopsis infans (Cyprinodontiformes: Poeciliidae) in the Lago de Pátzcuaro, Central Mexico

Ecología trófica del pez exótico Guatapote del Lerma Poeciliopsis infans (Cyprinodontiformes: Poeciliidae) en el Lago de Pátzcuaro, Región Central de México.

JUAN PABLO RAMIREZ HERREJON RODRIGO MONCAYO ESTRADA JAVIER CARAVEO PATIÑO EDUARDO FRANCISCO BALART PAEZ (2013)

"Ecología trófica del pez exótico Guatapote del Lerma Poeciliopsis infans (Cyprinodontiformes: Poeciliidae) en el Lago de Pátzcuaro, Región Central de México. Exotic fish species has caused several impacts on aquatic biodiversity. The Lago de Pátzcuaro has some well-studied exotic species, except the Lerma livebearer Poeciliopsis infans. This fish species was introduced into the Lago de Pátzcuaro before 1997 and the aspects of its biology are still unknown. In this study we assessed aspects of the trophic ecology of this exotic fish, P. infans, using gut content and stable isotope analysis to understand its capacity to tolerate anthropogenic environmental degradation in the Lago de Pátzcuaro. We also determined its trophic guild position (TP) using the TrophLab Program and stable isotope. Niche breadth was calculated by standardized Levins’ Index (Bi). Fish was captured with a seine during wet and dry seasons at six environmentally different sites and gut contents were obtained. We analyzed a total of 239 gut contents of P. infans. The contribution of each food item in the diet was quantified using frequency of occurrence and area percentage. The importance of each prey item was determined according to the index of relative importance (IRI), and the omnivory index (OI) was used to assess the feeding behavior. Fish were categorized by size and the diet was compared between fish sizes and sites. Dorsal muscle tissue and water hyacinth tissue was obtained for nitrogen isotope signature (δ15N) analysis. Additionally, we measured water and habitat quality to evaluate environmental conditions at each site. We concluded that P. infans is an omnivore (OI=0.28) that consumes mainly detritus (44%), epiphytic diatoms (37%), and secondary on terrestrial insects (6%) and zooplankton (10%). The fish can behave as a specialist (Bi=0.39) or generalist (Bi=0.68) and as a primary consumer (TROPH=2.2; TP=2.3) with a feeding strategy that was the same at different sizes, seasons and sites. None of the evaluated sites showed good environmental quality. We argue that P. infans can tolerate changes in water quality and feeding items availability, because it can exploit resources in multiple trophic webs. However, this species could be dependent on habitat complexity, especially in the aquatic vegetation cover."

Article

shallow lake, introduced species, tolerant species, ecological strategy, trophic ecology BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA ANIMAL (ZOOLOGÍA) ECOLOGÍA ANIMAL

Caracterización de fundentes para molde de colada continua de acero

ALEJANDRO CRUZ RAMIREZ MARISSA VARGAS RAMIREZ (2012)

Los fundentes para molde de colada continua de acero cumplen diferentes funciones clave para obtener planchones de acero de óptima calidad. En este trabajo, se caracterizaron cuatro fundentes comerciales mediante pruebas de laboratorio (Estudio petrográfico, difracción de rayos X y microscopía electrónica de barrido con microanálisis). La caracterización indica que los fundentes están constituidos por simple mezcla mecánica de minerales utilizando feldespatos y arcillas como materiales base, que contienen SiO2, Al2O3, Na2O y en menor proporción K2O, MgO, Fe2O3 y MnO; la caliza como fuente principal de CaO, fluorita (CaF2) como fluidificante y grafito como fuente de carbono. Esta información es útil para establecer criterios de diseño para obtener fundentes con materiales disponibles en el mercado nacional..

Fluxes for continuous casting mold of steel fulfill several key functions in order to produce slab steel of good quality. In this work, four commercial fluxes were characterized by laboratory tests (Petrographic study, X-ray diffraction and scanning electronic microscope with

microprobe). The characterization of the commercial fluxes reveals that they are produced by simple mechanical blend of minerals, using feldspars and clays as base materials, containing SiO2, Al2O3, Na2O and in less quantity K2O, MgO, Fe2O3 y MnO; limestone as the main source of CaO, fluorspar (CaF2) used to control the viscosity and graphite as carbon source. This information is useful to establish design parameters to obtain fluxes with raw materials available in the local market.

Article

INGENIERÍA Y TECNOLOGÍA TECNOLOGÍA METALÚRGICA Fundentes Colada continua Minerales Acero Planchón Pulvimetalurgia Fluxes Continuous casting Minerals Steel Slab Powder metallurgy

IMPORTANCIA DE LA MARCA TERNASCO DE ARAGON CON IGP MEDIDAA TRAVES DEL METODO DE ANALISIS CONJUNTO DESDE EL PUNTO DE VISTA DEL CONSUMIDOR

RICARDO RAFAEL ULLOA CASTAÑEDA (2007)

The objective of this paper is to analyze the value of a generic quality label linked to a specific region as it the Ternasco de Aragon (TA). We adopt a multidimensional approach from a consumer perspective. From a representative sample from this region, consumers segments are defined taking into account their experience in lamb meat consumption. For each segment, we analyze the consumers' knowledge, attitudes and preferences towards the quality label. Results indicate than consumers associate the label TA to a high quality label taking into account the organoleptic characteristics, the feed used and the close links to both the specific region and the cultural heritage. Moreover, the two considered market segments identify the quality label as the most important attribute when buying lamb meat. In general terms, consumers prefer a rose meat with some fat and bought directly to traditional butchers.

El objetivo de este trabajo se centra en analizar el valor de una marca genérica de calidad ligada a un territorio como es el Ternasco de Aragón (TA) en España. Para ello se adopta un enfoque multidimensional desde la perspectiva del consumidor. A partir de una muestra representativa de consumidores en la mencionada región, se segmenta a la población en base al nivel o experiencia de consumo en relación con la carne de cordero. A continuación, para los diferentes segmentos, se analiza el grado de conocimiento de la marca, sus actitudes hacia ella y las preferencias hacia la marca de calidad. Los resultados obtenidos en este trabajo confirman que los consumidores asocian a la marca TA una imagen de calidad basada en sus las cualidades organolépticas, la forma de alimentación del ganado y el propio origen geográfico de la producción. Asimismo, para los dos grupos de consumidores analizados la marca es el principal atributo considerado, junto con la forma de presentación. En términos generales, los consumidores prefieren un producto con la carne más rosada, con grasa y comprado directamente al carnicero en un establecimiento tradicional.

Article

Quality label differentiation attributes conjoint analysis Marca estrategia de diferenciación atributos análisis conjunto CIENCIAS ECONÓMICAS CIENCIAS SOCIALES

The burden of disease in older people and implications for health policy and practice

Martin Prince Fan Wu Yanfei Guo LUIS MIGUEL FRANCISCO GUTIERREZ ROBLEDO Martin O´Donnell Richard Sullivan Salim Yusuf (2015)

Summary:

23% of the total global burden of disease is attributable to disorders in people aged 60 years and older. Although the proportion of the burden arising from older people (≥60 years) is highest in high-income regions, disability-adjusted life years (DALYs) per head are 40% higher in low-income and middle-income regions, accounted for by the increased burden per head of population arising from cardiovascular diseases, and sensory, respiratory, and infectious disorders. The leading contributors to disease burden in older people are cardiovascular diseases (30·3% of the total burden in people aged 60 years and older), malignant neoplasms (15·1%), chronic respiratory diseases (9·5%), musculoskeletal diseases (7·5%), and neurological and mental disorders (6·6%). A substantial and increased proportion of morbidity and mortality due to chronic disease occurs in older people. Primary prevention in adults aged younger than 60 years will improve health in successive cohorts of older people, but much of the potential to reduce disease burden will come from more effective primary, secondary, and tertiary prevention targeting older people. Obstacles include misplaced global health priorities, ageism, the poor preparedness of health systems to deliver age-appropriate care for chronic diseases, and the complexity of integrating care for complex multimorbidities. Although population ageing is driving the worldwide epidemic of chronic diseases, substantial untapped potential exists to modify the relation between chronological age and health. This objective is especially important for the most age-dependent disorders (ie, dementia, stroke, chronic obstructive pulmonary disease, and vision impairment), for which the burden of disease arises more from disability than from mortality, and for which long-term care costs outweigh health expenditure. The societal cost of these disorders is enormous.

Article

MEDICINA Y CIENCIAS DE LA SALUD Ciencias médicas Ciencias clínicas Geriatría Procesos patológicos Enfermedad Atributos de la enfermedad Personas mayores Geriatrics Pathological processes Disease Disease attributes Elderly

Evaluación de atributos turísticos de Ixtapan de la Sal, Estado de México.

ADRIAN URIOSTEGUI FLORES ALMA VILLASEÑOR FRANCO BLANCA ROSA REYES NATERAS (2018)

In this work is carried out an evaluation of the tourist attributes of the city of Ixtapan de la Sal, Estado de Mexico. In the methodology was used qualitative research sampling, specifically with respect to samples for convenience, and samples of type cases. The findings show that the attributes evaluated satisfactorily were architecture conservation, and historical and religious sites (15%), and traditional festivals (13%).Among the attributes evaluated in an unsatisfactory manner were public safety and surveillance (24%), lack of information about tourist information, and lack of shelters and guides to know and navigate important places in the city (15%).

Article

Tourism Evaluation tourism attributes CIENCIAS SOCIALES GEOGRAFÍA OTRAS ESPECIALIDADES GEOGRÁFICAS

WHITE LIGHT GENERATION THROUGH EXCIPLEX AND DOWN-CONVERSION MECHANISMS FOR ORGANIC SOLID-STATE LIGHTING

WILSON BERNAL PINILLA (2020)

"This work reports the experimental study of two mechanisms, exciplex and down-conversion, to obtained white light with organic and hybrid materials for solid-state lighting (SSL). Exciplexes are complex states generated by intermolecular interaction between two molecules, usually an electron donor and an acceptor material; they were studied in the OLED structure: ITO/HTL/EML/ETL/Ca-Ag. Commercial materials and a new carbazole derivative were employed as the emissive layer (EML), and for the first-time, exciplex emissions from two interfaces were achieved. The thickness of the hole transport layer (HTL) was a determinant parameter for the exciplex states formation at HTL/EML interface. Meanwhile, the appropriate barrier energy between LUMO levels of the EML and ETL was crucial in allowing the bimolecular states to emerge at the EML/ETL interface. Therefore, due to emissions from the EML (S1-S0 transitions) and the two interfaces, a broad electroluminescence spectrum corresponding to white light with excellent CIE (0.31, 0.33) and CRI >85 was accomplished. The devices exhibited acceptable luminance (< 9000 cdm-2) and turn-on voltage (5 V). On the other hand, the studied down-conversion mechanism involved the full or partial absorption of the light emitted from an inorganic LED by the organic material. Thicknesses of the organic films were optimized to obtain a proper absorption of the converter material, which allowed the adequate combination between the electroluminescence (EL) and photoluminescence (PL) intensities from LED and the organic converters, respectively. Thus, the mechanism was tested in partial and full conversion configuration known as luminesce converter (LUCO). Using benzothiadiazole derivatives as organic converter, LUCO devices exhibited white light with excellent CIE (0.32, 0.33), outstanding CRI (>90) and good conversion efficiency of 73%. With these results, it was demonstrated that organic materials could be a real alternative in the field of SSL."

Doctoral thesis

Organic semiconductors Down-conversion OLEDs Exciplex Solid-state lighting (SSL) CIE CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ÓPTICA ILUMINACIÓN ILUMINACIÓN

Microorganismos del suelo y cinética de carbono en ecosistemas del monte Tláloc.

VIRGINIA MARTINEZ ROJAS (2015)

Tesis (Doctorado en Ciencias, especialista en Edafología).- Colegio de Postgraduados, 2015.

Los ecosistemas forestales juegan un papel importante en la fijación de carbono, a través de ellos se da el intercambio de dióxido de carbono (CO2) entre la atmósfera y la superficie terrestre. Parte del carbono fijado por las plantas entra al suelo y parte regresa a la atmósfera a través de la descomposición del material vegetal muerto. Varios factores bióticos y abióticos determinan la cantidad de carbono que entra al suelo. En el presente estudio se evaluaron algunos de esos factores que influyen en la caída de hojarasca, la descomposición y en los flujos de CO2 del suelo en el bosque de oyamel del monte Tláloc. Además se determinó con tecnologías metagenómicas de última generación la diversidad de las comunidades bacterianas del suelo en los ecosistemas de encino, oyamel, pino y pradera alpina. De la hojarasca caída durante el año, 67% correspondió a acículas y 23% a ramas. La descomposición, medida como pérdida de peso fue de 44% para acículas y de 32% para ramas a los 475 días; las constantes de descomposición (k) fueron de 0.439 año-1 para acículas y de 0.294 año-1 para ramas. Los flujos de CO2 asociadas a la respiración del suelo fueron mayores en época de lluvia. La tasa de mineralización bajo condiciones controladas de temperatura y humedad en los suelos de oyamel fue afectada por la calidad de la hojarasca; en suelos colectados a menor altitud la tasa de mineralización fue de 36 mg C kg-1 suelo día-1 y en suelos de mayor altitud fue de 21 mg C kg-1 suelo día-1. Los filos identificados en las muestras de suelo de los diferentes ecosistemas fueron: Actinobacteria, Acidobacteria, Protebacteria, Firmicutes y Tenericutes, los cuales cambiaron de acuerdo al tipo de ecosistema y al gradiente altitudinal; el filo más abundante fue Actinobacteria, en particular en bosque de encino y oyamel; Tenericutes se encontró solo en encino y pradera alpina. La diversidad alfa fue mayor en encino que en los otros ecosistemas. El suelo de bosque de encino albergó 14 géneros de bacterias, siendo el más abundante Arthrobacter con 7.5% del total de secuencias, le siguió Burkholderia con 3.5% del total. _______________ SOIL MICROORGANISMS AND CARBON KINETICS OF MOUNT TLALOC ECOSYSTEMS. ABSTRACT: Forest ecosystems play an important role in carbon sequestration, through them exchange of carbon dioxide (CO2) between the atmosphere and land surface occurs. Part of the carbon fixed by plants enters into the soil and other part returns to the atmosphere through litter decomposition. Various biotic and abiotic factors determine the amount of carbon entering the soil. In this study some factors that influence litter fall, decomposition and CO2 fluxes on soils of fir forest at mount Tlaloc were evaluated. It was also determined the diversity of soil bacterial communities in ecosystems of oak, fir, pine and alpine grass land using technologies of metagenomics. Litter fall during the year, was 67% needles and 23% branches. The decomposition, measured as weight loss was 44% for needles and 32% for branches at 475 days after the establishment of the experiment; decomposition constants (k) were 0.439 year-1 for needles and 0.294 year-1 for branches. The CO2 fluxes associated with soil respiration were higher in the rainy season. The mineralization rate under controlled conditions of temperature and moisture on fir soils was affected by the litter quality; mineralization rate was 36 mg C kg-1 day-1 in soil samples collected at lower altitude and 21 mg C kg-1 day-1 in soils at higher altitude. The phyla identified in soil samples from the different ecosystems were: Actinobacteria, Acidobacteria, Proteobacteria, Firmicutes and Tenericutes, which changed according to the type of ecosystem and the altitudinal gradient; phylum Actinobacteria was the most abundant, particularly in oak and fir forest; Tenericutes was found only in oak and alpine grassland. Alpha diversity was higher in oak than in the other ecosystems. The oak forest floor housed 14 genus of bacteria, the most abundant was Arthrobacter with 7.5% of sequences and Burkholderia with 3.5%.

Doctoral thesis

Hojarasca Tasa de descomposición Flujos de CO2 Mineralización de C. Diversidad bacteriana Litter Decomposition rate CO2 fluxes C mineralization Bacterial diversity Edafología Doctorado CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO CIENCIAS DEL SUELO (EDAFOLOGÍA) MICROBIOLOGÍA DE SUELOS

TROPHIC CIRCULATION IN ECOSYSTEMS

Manuel Jesús Zetina Rejón Víctor Hugo Cruz Escalona (2015)

The trophic aspect of ecology has been studied for more than six decades; in this contribution we address theoretical aspects relative to the concept of trophic ow at the ecosystem level and from the thermodynamics point of view. Much of this knowledge is greatly based on the consideration that ecosystems are functional units that are worth global study. Undoubtedly, a key element in the study of ecosystems relates to energy circulation through food webs. Although trophic ecology has been a su ciently studied topic, we have not found a formal description of the trophic ow concept. Thus, this work proposes a concept based on movements of matter and energy amongst the biological components of the ecosystem. We include Odum's universal model of energy ow to synthesize the concept of trophic ow in the ecosystem. Additionally, we analyze the ecosystem thermodynamics, we discuss the characteristics of ecosystems as open and dissipation systems, and we indicate which types of mechanisms can regulate trophic ow in ecosystem. Finally, we discuss how the study of trophic ow is helpful for characterization of ecosystems structure and function, and it is important to consider it in ecosystems-based management as well. 

The trophic aspect of ecology has been studied for more than six decades; in this contribution we address theoretical aspects relative to the concept of trophic ow at the ecosystem level and from the thermodynamics point of view. Much of this knowledge is greatly based on the consideration that ecosystems are functional units that are worth global study. Undoubtedly, a key element in the study of ecosystems relates to energy circulation through food webs. Although trophic ecology has been a su ciently studied topic, we have not found a formal description of the trophic ow concept. Thus, this work proposes a concept based on movements of matter and energy amongst the biological components of the ecosystem. We include Odum's universal model of energy ow to synthesize the concept of trophic ow in the ecosystem. Additionally, we analyze the ecosystem thermodynamics, we discuss the characteristics of ecosystems as open and dissipation systems, and we indicate which types of mechanisms can regulate trophic ow in ecosystem. Finally, we discuss how the study of trophic ow is helpful for characterization of ecosystems structure and function, and it is important to consider it in ecosystems-based management as well. 

Article

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA Ecosystem trophic flow food web thermodynamics dissipative structures