Filtros
Filtrar por:
Tipo de publicación
- Event (4582)
- Artículo (1101)
- Dataset (932)
- Tesis de maestría (547)
- Tesis de doctorado (378)
Autores
- Servicio Sismológico Nacional (IGEF-UNAM) (4582)
- Thomas Payne (298)
- Fernando Nuno Dias Marques Simoes (250)
- Ravi Singh (204)
- Jose Crossa (98)
Años de Publicación
Editores
- UNAM, IGEF, SSN, Grupo de Trabajo (4582)
- International Maize and Wheat Improvement Center (644)
- Cenoteando, Facultad de Ciencias, UNAM (cenoteando.mx) (249)
- Instituto Mexicano de Tecnología del Agua (242)
- Instituto Tecnológico y de Estudios Superiores de Monterrey (108)
Repositorios Orígen
- Repositorio de datos del Servicio Sismológico Nacional (4582)
- Repositorio Institucional de Datos y Software de Investigación del CIMMYT (682)
- Repositorio institucional del IMTA (659)
- Repositorio Institucional de Publicaciones Multimedia del CIMMYT (426)
- Cenotes de Yucatan (250)
Tipos de Acceso
- oa:openAccess (8127)
- oa:embargoedAccess (13)
- oa:Computación y Sistemas (1)
Idiomas
Materias
- Sismología (13746)
- CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA (5150)
- CIENCIAS DE LA TIERRA Y DEL ESPACIO (4631)
- GEOFÍSICA (4585)
- SISMOLOGÍA Y PROSPECCIÓN SÍSMICA (4584)
Selecciona los temas de tu interés y recibe en tu correo las publicaciones más actuales
Conjuntos de dinoflagelados del Cretácico Inferior de Colombia
Assemblages of dinoflagellate from the Lower Cretaceous of Colombia
Maribel Reyes Tixteco (2023, [Tesis de maestría])
Los dinoflagelados se usan como indicadores en investigaciones ecológicas y son uno de los principales causantes de toxicidad en florecimientos algales nocivos (FANs). Estas microalgas producen quistes resistentes y fosilizables, los cuales son muy útiles como indicadores bioestratigráficos y paleoecológicos. Los dinoflagelados del Cretácico han sido ampliamente estudiados en estratos de latitudes medias y altas, pero los conjuntos tropicales casi no han sido estudiados. Para ayudar a remediar esta falta de conocimiento, se estudiaron cuantitativamente y cualitativamente el contenido de dinoflagelados de 50 muestras de núcleos de los pozos ANH-CR-MONTECARLO-1X y ANH-CON-06-ST-S, localizados en Colombia. La edad de la sedimentación en ambos pozos se interpreta como Albiano, aunque hay un poco de incertidumbre en la edad de inicio. Los taxones heterotróficos tienen menor riqueza de especies, pero presentan mayor abundancia, mientras que los autótrofos tienen mayor riqueza de especies pero menor abundancia. En el pozo ANH-CR-MONTECARLO-1X se identificaron 20 géneros y 24 especies, con altos valores de concentración total de 1,441.00 qst / gr sed, en la muestra IIES-PALY-6015 por la presencia de Subtilisphaera y 1,036.88 en la muestra IIES-PALY-6021 dominada por Muderongia. Dichas muestras son correlacionables con dos transgresiones marinas, del Albiano tardío (104.4 Ma) y el Albiano temprano (111 Ma) respectivamente. Además, indican que los ensamblajes de quistes en este pozo, están dominados por formas Peridinoideas y Ceratioideas. En el pozo ANH-CON-06-ST-S se encontraron 16 géneros y 15 especies, con un valor máximo de 3,539.62 qst / gr sed en la muestra IIES-PALY-5995 por el alto contenido de Subtilisphaera, y correlacionable con la transgresión marina del Albiano tardío (104.4 Ma). Los ensamblajes de quistes en este pozo, están dominados por las formas Peridinoideas. La litología y el contenido de palinomorfos de los pozos indican un ambiente nerítico interno (NI) a transicional (T), con mayor aporte de terrígenos en el pozo ANH-CON-06-ST-S. Se propone un clima cálido para el Cretácico Inferior por la alta diversidad de taxones autótrofos característicos de aguas cálidas y estratificadas.
Dinoflagellates produce resistant and fossilizable cysts, which are useful as biostratigraphic and paleoecological indicators. These microalgae are used as indicators in ecological studies and are one of the main causes of toxicity in harmful algal blooms (HABs). Cretaceous dinoflagellates have been extensively studied in mid- and high-latitude strata, but tropical assemblages have hardly been studied. To help remedy this lack of knowledge, the dinoflagellate content of 50 core samples from the ANH-CR-MONTECARLO-1X and ANH-CON-06-ST-S wells, located in Colombia, were quantitatively and qualitatively studied. The age of sedimentation in both wells is interpreted as Albian, although there is some uncertainty in the beginning of the depositional age. Heterotrophic taxa have lower species richness but higher abundance, while autotrophs have higher species richness but lower abundance. In the ANH-CR-MONTECARLO-1X well, 20 genera and 24 species were identified, with high total concentration values of 1,441.00 cst / gr sed, in the IIES-PALY-6015 sample, due to the presence of Subtilisphaera and 1,036.88 in the IIES sample -PALY-6021, dominated by Muderongia. These samples are correlable with two marine transgressions, from the late Albian (104.4 Ma) and early Albian (111 Ma) respectively. Furthermore, they indicate that the cyst assemblages in this well are dominated by hetrotrophic forms. In the ANH-CON-06-ST-S well, 16 genera and 15 species were found, with a maximum value of 3,539.62 qst / gr sed in the IIES-PALY-5995 sample due to the high content of Subtilisphaera, and correlated with the transgression marina from the late Albian (104.4 Ma). The cyst assemblages in this well are also dominated by the heterotrophic forms. The lithology and palynomorph content of the wells indicate an internal neritic (NI) to transitional (T) environment, with a higher terrigenous influx in the ANH-CON-06-ST-S well. A warm climate is proposed for the Lower Cretaceous due to the high diversity of autotrophic taxa characteristic of warm and stratified waters.
Dinoflagelados, Cretácico Inferior, Bioestratigrafía, Paleoambientes, Paleoecología Dinoflagellates, Lower Cretaceous, Biostratigraphy, Paleoenvironment, Paleoecology CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO GEOLOGÍA GEOLOGÍA REGIONAL GEOLOGÍA REGIONAL
Sonia Quijano (2020, [Artículo])
Pseudo-nitzschia is a cosmopolitan genus, some species of which can produce domoic acid (DA), a neurotoxin responsible for the Amnesic Shellfish Poisoning (ASP). In this study, we identified P. subpacifica for the first time in Todos Santos Bay and Manzanillo Bay, in the Mexican Pacific using SEM and molecular methods. Isolates from Todos Santos Bay were cultivated under conditions of phosphate sufficiency and deficiency at 16°C and 22°C to evaluate the production of DA. This toxin was detected in the particulate (DAp) and dissolved (DAd) fractions of the cultures during the exponential and stationary phases of growth of the cultures. The highest DA concentration was detected during the exponential phase grown in cells maintained in P-deficient medium at 16°C (1.14 ± 0.08 ng mL-1 DAd and 4.71 ± 1.11 × 10−5 ng cell-1 of DAp). In P-sufficient cultures DA was higher in cells maintained at 16°C (0.25 ± 0.05 ng mL-1 DAd and 9.41 ± 1.23 × 10−7 ng cell-1 of DAp) than in cells cultured at 22°C. Therefore, we confirm that P. subpacifica can produce DA, especially under P-limited conditions that could be associated with extraordinary oceanographic events such as the 2013–2016 "Blob" in the northeastern Pacific Ocean. This event altered local oceanographic conditions and possibly generated the presence of potential harmful species in areas with economic importance on the Mexican Pacific coast. © 2020 Quijano-Scheggia et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
domoic acid, domoic acid, kainic acid, Article, cell growth, controlled study, diatom, Mexico, morphology, nonhuman, Pacific Ocean, phylogeny, plant cell, plant growth, Pseudo nitzschia, toxin analysis, cell culture technique, classification, diatom, CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO OCEANOGRAFÍA OCEANOGRAFÍA
DANIEL BADILLO ZAPATA (2014, [Artículo])
This is second part from an experiment where the nitrogen retention of poultry by-product meal (PBM) compared to fishmeal (FM) was evaluated using traditional indices. Here a quantitative method using stable isotope ratios of nitrogen (δ15N values) as natural tracers of nitrogen incorporation into fish biomass is assessed. Juvenile rainbow trout (Oncorhynchus mykiss) were fed for 80 days on isotopically distinct diets in which 0, 33, 66 and 100% of FM as main protein source was replaced by PBM. The diets were isonitrogenous, isolipidic and similar in gross energy content. Fish in all treatments reached isotopic equilibrium by the end of the experiment. Two-source isotope mixing models that incorporated the isotopic composition of FM and PBM as well as that of formulated feeds, empirically derived trophic discrimination factors and the isotopic composition of fish that had reached isotopic equilibrium to the diets were used to obtain a quantitative estimate of the retention of each source of nitrogen. Fish fed the diets with 33 and 66% replacement of FM by PBM retained poultry by-product meal roughly in proportion to its level of inclusion in the diets, whereas no differences were detected in the protein efficiency ratio. Coupled with the similar biomass gain of fishes fed the different diets, our results support the inclusion of PBM as replacement for fishmeal in aquaculture feeds. A re-feeding experiment in which all fish were fed a diet of 100% FM for 28 days indicated isotopic turnover occurred very fast, providing further support for the potential of isotopic ratios as tracers of the retention of specific protein sources into fish tissues. Stable isotope analysis is a useful tool for studies that seek to obtain quantitative estimates of the retention of different protein sources. © 2014 Badillo et al.
nitrogen 15, nitrogen, protein intake, animal behavior, animal experiment, animal food, animal tissue, aquaculture, Article, biomass, controlled study, energy metabolism, food composition, juvenile animal, nonhuman, poultry by product meal, protein a CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO OCEANOGRAFÍA OCEANOGRAFÍA
Elena Nalesso (2019, [Artículo])
Many species of sharks form aggregations around oceanic islands, yet their levels of residency and their site specificity around these islands may vary. In some cases, the waters around oceanic islands have been designated as marine protected areas, yet the conservation value for threatened shark species will depend greatly on how much time they spend within these protected waters. Eighty-four scalloped hammerhead sharks (Sphyrna lewini Griffith & Smith), were tagged with acoustic transmitters at Cocos Island between 2005–2013. The average residence index, expressed as a proportion of days present in our receiver array at the island over the entire monitoring period, was 0.52±0.31, implying that overall the sharks are strongly associated with the island. Residency was significantly greater at Alcyone, a shallow seamount located 3.6 km offshore from the main island, than at the other sites. Timing of presence at the receiver locations was mostly during daytime hours. Although only a single individual from Cocos was detected on a region-wide array, nine hammerheads tagged at Galapagos and Malpelo travelled to Cocos. The hammerheads tagged at Cocos were more resident than those visiting from elsewhere, suggesting that the Galapagos and Malpelo populations may use Cocos as a navigational waypoint or stopover during seasonal migrations to the coastal Central and South America. Our study demonstrates the importance of oceanic islands for this species, and shows that they may form a network of hotspots in the Eastern Tropical Pacific. © 2019 Nalesso et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
article, Cocos Island, human, monitoring, nonhuman, resident, shark, South America, animal, Costa Rica, environmental protection, island (geological), movement (physiology), physiology, season, shark, Animals, Conservation of Natural Resources, Costa CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO OCEANOGRAFÍA OCEANOGRAFÍA
GABRIELA PINEDA GARCIA (2023, [Tesis de maestría])
CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO HIDROLOGÍA AGUAS SUBTERRÁNEAS AGUAS SUBTERRÁNEAS
MARIO ANDRES PARDO RUEDA (2015, [Artículo])
We inferred the population densities of blue whales (Balaenoptera musculus) and short-beaked common dolphins (Delphinus delphis) in the Northeast Pacific Ocean as functions of the water-column's physical structure by implementing hierarchical models in a Bayesian framework. This approach allowed us to propagate the uncertainty of the field observations into the inference of species-habitat relationships and to generate spatially explicit population density predictions with reduced effects of sampling heterogeneity. Our hypothesis was that the large-scale spatial distributions of these two cetacean species respond primarily to ecological processes resulting from shoaling and outcropping of the pycnocline in regions of wind-forced upwelling and eddy-like circulation. Physically, these processes affect the thermodynamic balance of the water column, decreasing its volume and thus the height of the absolute dynamic topography (ADT). Biologically, they lead to elevated primary productivity and persistent aggregation of low-trophic-level prey. Unlike other remotely sensed variables, ADT provides information about the structure of the entire water column and it is also routinely measured at high spatial-temporal resolution by satellite altimeters with uniform global coverage. Our models provide spatially explicit population density predictions for both species, even in areas where the pycnocline shoals but does not outcrop (e. g. the Costa Rica Dome and the North Equatorial Countercurrent thermocline ridge). Interannual variations in distribution during El Niño anomalies suggest that the population density of both species decreases dramatically in the Equatorial Cold Tongue and the Costa Rica Dome, and that their distributions retract to particular areas that remain productive, such as the more oceanic waters in the central California Current System, the northern Gulf of California, the North Equatorial Countercurrent thermocline ridge, and the more southern portion of the Humboldt Current System. We posit that such reductions in available foraging habitats during climatic disturbances could incur high energetic costs on these populations, ultimately affecting individual fitness and survival. © 2015, public library of science. All rights reserved.
CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO OCEANOGRAFÍA OCEANOGRAFÍA
Vibrissa growth rate in California sea lions based on environmental and isotopic oscillations
MARTHA PATRICIA ROSAS HERNANDEZ (2018, [Artículo])
Pinniped vibrissae provide information on changes in diet at seasonal and annual scales; however, species-specific growth patterns must first be determined in order to interpret these data. In this study, a simple linear model was used to estimate the growth rate of vibrissae from adult female California sea lions (Zalophus californianus) from San Esteban Island in the Gulf of California, Mexico. The δ15N and δ13C values do not display a marked oscillatory pattern that would permit direct determination of the time period contained in each vibrissa; thus, time (age) was calculated in two ways: 1) based on the correlation between the observed number of peaks (Fourier series) in the δ15N profile and the length of each vibrissa, and 2) through direct comparison with the observed number of peaks in the δ15N profile. Cross-correlation confirmed that the two peaks in the δ15N profile reflected the two peaks in the chlorophyll-a concentration recorded annually around the island. The mean growth rate obtained from the correlation was 0.08 ± 0.01 mm d-1, while that calculated based on the observed number of peaks was 0.10 ± 0.05 mm d-1. Both are consistent with the rates reported for adult females of other otariid species (0.07 to 0.11 mm d-1). Vibrissa growth rates vary by individual, age, sex, and species; moreover, small differences in the growth rate can result in significant differences over the time periods represented by the isotopic signal. Thus, it is important to assess this parameter on a species-by-species basis. © 2018 Rosas-Hernández et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
carbon, nitrogen, animal, California, chemistry, diet, female, island (geological), Mexico, Otariidae, physiology, Animals, California, Carbon Isotopes, Diet, Female, Islands, Mexico, Nitrogen Isotopes, Sea Lions CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO OCEANOGRAFÍA OCEANOGRAFÍA
Mapas y esferas que redibujaron el mundo: el arribo de Cristóbal Colón a Cipango
JUAN ANTONIO LAVIADA (2023, [Capítulo de libro])
Universidad Autónoma Metropolitana (México). Unidad Azcapotzalco. División de Ciencias y Artes para el Diseño. Departamento de Evaluación del Diseño en el Tiempo. Área de Estudios Urbanos.
Desde su arribo a las islas, Colón estaba convencido de estar en las cercanías de Cipango, nada parecía convencerlo de lo contrario; todo lo que observa lo interpreta desde su convicción de estar en Asia. En el primer apartado de este capítulo se intentará demostrar tomando como referencia los escritos del propio Cristóbal Colón que éste consultó cartas de navegación, esferas e incluso tenía la firme intención de realizar una carta de navegación con el fin de mostrar la ubicación de Cipango. El segundo apartado refiere al hecho de que la única fuente documental sobre Cipango de la cual se tenía noticia dependía exclusivamente de narraciones de Marco Polo y se debatirá si Colón conoció o no dichos relatos.
Cartography--America--History. America--Discovery and exploration. Columbus, Christopher--Influence. Cartografía -- Historia. GA401 CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO GEOGRAFÍA CARTOGRAFÍA GEOGRÁFICA
Índice de calidad del agua de cuerpos de agua dulce kársticos de Cancún y Playa del Carmen
EUNICES ARELY HERNANDEZ DE LA O (2023, [Tesis de maestría])
CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO HIDROLOGÍA AGUAS SUBTERRÁNEAS AGUAS SUBTERRÁNEAS
GEORGINA ROMERO GENARO (2023, [Otro, Trabajo terminal, especialidad])
El Acinetobacter es un cocobacilo aerobio gramnegativo que se ha descrito desde un
organismo de patogenicidad cuestionable hasta el de un agente infeccioso de gran
importancia hospitalaria en todo el mundo y se presenta en pacientes susceptibles con
mayor frecuencia en las unidades de cuidados intensivos (UCI). En nuestro país existen
estudios relacionado con este microorganismo que sustenta la importancia de la
prevención.
Este trabajo de investigación titulado “Prevención por acinetobacter baumannii en la
unidad de cuidados intensivos de un hospital de segundo nivel de atención”, tiene como
objetivo prevenir las infecciones asociadas por Acinetobacter baumannii. Mediante tres
variables las cuales son: higiene de manos, limpieza y desinfección de material y equipo
y la técnica de barrera máxima.
Se realizó un estudio de tipo cuantitativo, descriptivo y observacional. La muestra de
estudio está conformada por 30 profesionales de enfermería que se encuentran adscritas
a la UCI. Se realiza una evaluación de conocimientos a través de un instrumento sobre
las medidas de prevención que consta de 10 preguntas con opción multiple donde los
criterios de evaluación son: muy bueno, bueno y deficiente esta medición sustenta la
necesidad de la realización de este estudio. Con respecto al conocimiento que tiene el
personal profesional de enfermería encuestado sobre la eficiencia de las medidas de
prevención por acinetobacter baumannii se obtuvo un indicador de eficiencia general
bueno de un 72%. Los resultados por variable fueron los siguientes: el 80% fue de
conocimiento, el 63% al lavado de manos, 72% corresponde a la limpieza y desinfección
del material y equipo así como por último se obtuvo el 80% en la técnica de barrera
máxima.
Estos resultados nos permiten implementar las medidas preventivas mediante la difusión
con base en la NOM-045-SSA-2015 para la vigilancia epidemiológica, prevención y
control de las infecciones asociadas a la atención de la salud, al personal de enfermería
de la UCI.
Acinetobacter is a gram-negative aerobic coccobacillus that has been described from an
organism of questionable pathogenicity to that of an infectious agent of great hospital
importance worldwide and occurs in susceptible patients more frequently in intensive care
units (ICU). In our country there are studies related to this microorganism that support the
importance of prevention.
This research work entitled "Prevention of Acinetobacter baumannii in the intensive care
unit of a second level care hospital", aims to prevent infections associated with
Acinetobacter baumannii. By means of three variables which are: hand hygiene, cleaning
and disinfection of airway material and equipment and the maximum barrier technique.
A quantitative, descriptive and observational study was carried out. The study sample
consisted of 30 nursing professionals assigned to the ICU. Knowledge was evaluated by
means of an instrument on prevention measures consisting of 10 multiple-choice
questions where the evaluation criteria are: very good, good and deficient, this
measurement supports the need to carry out this study. With respect to the knowledge
that the professional nursing personnel surveyed have about the efficiency of
acinetobacter baumannii prevention measures, a good overall efficiency indicator of 72%
was obtained. The results by variable were as follows: 80% were for knowledge, 63% for
hand washing, 72% for cleaning and disinfection of material and equipment, and 80% for
the maximum barrier technique.
These results allow us to implement preventive measures through dissemination based
on NOM-045-SSA-2015 for epidemiological surveillance, prevention and control of
healthcare-associated infections, to ICU nursing staff.
MEDICINA Y CIENCIAS DE LA SALUD CIENCIAS MÉDICAS acinetobacter baumannii, prevención, lavado de manos, desinfección y la técnica de barrera máxima. acinetobacter baumannii, prevention, hand washing, disinfection and maximum barrier technique.