Browsing Ciencias básicas by Title
Now showing items 1546-1565 of 1623
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Ultrastructural and microbial analyses of cellulose degradation in leaf-cutter ant colonies
(2017)Leaf-cutter ants (Atta and Acromyrmex) use fresh leaves to cultivate a mutualistic fungus (Leucoagaricus gongylophorus) for food in underground gardens. A new ant queen propagates the cultivar by taking a small fragment ... -
Ultrastructural demonstration of the model of Litopenaeus vannamei (Crustacea, Penaeidae) male sexual maturation and spermatozoal capacitation
(2016)The present study demonstrates ultrastructurally the model of Litopenaeus vannamei male sexual maturation and spermatozoal capacitation. The results show that phase 1 of the model occurred in the seminiferous tubules and ... -
Ultrastructure and histology of organogenesis induced from shoot tips of maize (Zea mays, Poaceae)
(Revista de Biología Tropical; vol.57(supl.1), 2009-11)Shoot tips of maize (Zea mays L.) were cultured on Murashige and Skoog medium supplemented with 2 mg/l BA +1 mg/l 2,4-D +40 mg/l, to investigate phases of ontogenetic development. The study used light microscopy as well ... -
Ultrastructure of Deinopis egg sac (Araneae: Deinopidae)
(2014)Attacks by predators and parasitoids on spider eggs are common. To counteract their negative effect, spiders have evolved a series of behaviours and features related to their egg sacs. In the genus Deinopis (Deinopidae) ... -
Uniform sparse bounds for discrete quadratic phase Hilbert transforms
(2017-09)Consider the discrete quadratic phase Hilbert Transform acting on $\ell^{2}(\mathbb{Z})$ finitely supported functions $$ H^{\alpha} f(n) : = \sum_{m \neq 0} \frac{e^{i\alpha m^2} f(n - m)}{m}. $$ We prove that, ... -
Unraveling the whole story: An Ultraestructural study of the common bean "amachamiento" disease caused by Aphelencoides besseyi
(2019-07-21)Se identificó Aphelencoides besseyi como responsable del amachamiento del frijol -
Unveiling the Hidden Bat Diversity of a Neotropical Montane Forest
(2016-10)Mountain environments, characterized by high levels of endemism, are at risk of experiencing significant biodiversity loss due to current trends in global warming. While many acknowledge their importance and vulnerability, ... -
Updated checklist and analysis of completeness of the marine fish fauna of Isla del Coco, Pacific of Costa Rica
(2016)Isla del Coco, Costa Rica, is one of the five groups of oceanic islands of the Eastern Tropical Pacific (ETP), and is considered one of the most diverse. Since the mid-19th century, it has been the target of a number of ... -
Upwelling Increases Net Primary Production of Corals and Reef-Wide Gross Primary Production Along the Pacific Coast of Costa Rica
(2015-12-23)Photosynthetic production is a key ecosystem service provided by tropical coral reefs, but knowledge about the contribution of corals and other reef-associated organisms and the controlling environmental factors is scarce. ... -
Urban noise influences vocalization structure in the House Wren Troglodytes aedon
(2013)Urban habitats are noisy and constrain acoustic communication in birds. We analysed the effect of anthropogenic noise on the vocalization characteristics of House Wrens Troglodytes aedon at two sites with different noise ... -
Use of a theoretical prediction method and quantum chemical calculations for the design, synthesis and experimental evaluation of three green corrosion inhibitors for mild steel
(2020)Three phenylmethanimine derivatives (Schiff bases) were designed after a theoretical prediction of their corrosion inhibition efficiencies and a corroboration through the use of quantum chemical calculations. The molecules ... -
Using eDNA to determine the source of organic carbon in seagrass meadows
(2017)Seagrasses sequester globally significant amounts of carbon (C), which is stored mainly in the sediment. BothC fixation by the seagrass (autochthonous) and the trapping of organic matter that is derived from outside ... -
Using generalized logistics regression to forecast population infected by Covid-19
(2020-04-05)In this work, a proposal to forecast the populations using generalized logistics regression curve fitting is presented. This type of curve is used to study population growth, in this case population of people infected ... -
Uso de herramientas estadísticas para la predicción estacional del campo de precipitación en América Central como apoyo a los Foros Climáticos Regionales. 1: Análisis de tablas de contingencia.
(Revista de Climatología, Vol 12 (2012): 61-79, 2012-11-21)Se utilizó la técnica estadística del análisis de tablas de contingencia para elaborar esquemas predictivos de los campos de precipitación en América Central. Como primer paso, se produjeron índices de estos campos utilizando ... -
Uso de herramientas estadísticas para la predicción estacional del campo de precipitación en América Central como apoyo a los Foros Climáticos Regionales. 2: Análisis de Correlación Canónica.
(Revista de Climatología, Vol 12 (2012): 93-105, 2012-12-20)Se elaboró un pronóstico climático estacional en América Central basado en el Análisis de Correlación Canónica (ACC). Como predictores se usaron las temperaturas superficiales del mar de los océanos circundantes al istmo ... -
El Uso de las Redes Sociales para aumentar el alcance de la Red Sismológica Nacional
(2017-12)La Red Sismológica Nacional de Costa Rica (RSN: UCR-ICE) realiza, desde 1973, investigación en Sismología y Vulcanología. A partir del 2012 la RSN ha fortalecido sus esfuerzos de divulgación de material científico y educativo ... -
Uso de material artificial para la construcción de nidos de aves: potenciales consecuencias sobre el éxito reproductivo de Turdus grayi (Passeriformes: Turdidae)
(2020-07-29)El exponencial aumento en la población humana ha generado una rápida expansión de las zonas urbanas. El aumento en el área de las ciudades produce que algunas especies entren en contacto directo con nuevos recursos ... -
Uso de un modelo de aguas someras para analizar la influencia del Atlántico Tropical Norte y del Pacı́fico Ecuatorial del Este sobre la circulación atmosférica en los mares Intra-Americanos
(2007-09)A shallow water model was used to simulate the anomalous circulation over the Intra American Seas (IAS), due to heat forcing fun ctions located at the Tropical North Atlantic and the Eastern Equatorial Pacific Oceans, ...