Listar Ciencias básicas por título
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Radionucleídos naturales y antropogénicos en el estuario del Golfo de Nicoya, Costa Rica
(2002)The activity of isotopes of the Uranium, and Thorium series (228Ac, 212Bi, 212Pb, 226Ra, 214Bi, 214Pb) as well as 40K and 137 Cs was monitored on sediment samples collected in the Gulf of Nicoya estuary (9 30 N 84 45 W), ... -
Rafael Francisco Osejo: ¿un hombre de ciencia de su época?
(2022)La construcción de las sociedades actuales ha sido posible gracias a los aportes de numerosos personajes a la política, a la economía, a las artes y a las ciencias. Considerado uno de los actores del proceso de independencia ... -
Ramphocelus passerinii alimentando pichones de Turdus grayi y notas sobre la reproducción de otras especies de Ramphocelus
(2015)En esta nota presentamos observaciones de un Ramphocelus passerinii alimentando juveniles de Turdus grayi. Además, ampliamos los registros de la época reproductiva para Ramphocelus costaricensis y Ramphocelus carbo. Esta ... -
Random Electric Field Instabilities of Relaxor Ferroelectrics
(2017-06-13)Relaxor ferroelectrics are complex oxide materials which are rather unique to study the effects of compositional disorder on phase transitions. Here, we study the effects of quenched cubic random electric fields on the ... -
Range expansion and noteworthy records of Costa Rican birds (Aves)
(2018-01-19)We present new distribution information for 19 species of Costa Rican birds. Thirteen species show changes in altitudinal distribution, 9 are recorded at higher elevations such as Egretta rufescens (Gmelin, 1789), Heliomaster ... -
Range expansion of the Gulf Coast Toad, Incilius valliceps (Wiegmann, 1833) (Anura, Bufonidae), from Costa Rica
(2020-06-02)We report the range expansion of the Gulf Coast Toad, Incilius valliceps (Wiegmann, 1833), from tropical moist forests to tropical wet forests and towards southeastern Costa Rica. We evaluated erroneous reports of this ... -
Range extension for the Costa Rican Blindsnake, Amerotyphlops costaricensis (Jiménez & Savage, 1962) (Serpentes, Typhlopidae)
(2020-08-08)Amerotyphlops. costaricensis is difficult to observe in the field and is considered a rare species. There are fewer than ten individuals deposited in museum collections, representing roughly one population in both Nicaragua ... -
Range overlap and association patterns in the tent-making bat Artibeus watsoni
(2007)Space use and ranging patterns of individuals have traditionally been used to identify social systems, and the amount of overlap in the home ranges of individuals can provide indirect information about the likelihood of ... -
Rapid assessment of myxomycetes in Isla Calero and Isla Brava, Costa Rica
(2022-03-02)The geography of the northeasternmost section of Costa Rica corresponds to river islands sparsely populated and highly protected for biological conservation. Myxomycetes had not been studied in that part of such Central ... -
Rapid assessment of the distribution of myxomycetes in a southwestern Amazon forest
(2012-07-02)The distribution of fruit bodies of myxomycetes under different ecological conditions at the Los Amigos Biological Station in southeastern Peru was studied. Six study areas were surveyed using a combined field-laboratory ... -
Rapid bioerosion in a tropical upwelling coral reef
(2018)Coral reefs persist in an accretion-erosion balance, which is critical for understanding the natural variability of sediment production, reef accretion, and their effects on the carbonate budget. Bioerosion (i.e. biodegradation ... -
Rapid Determination of the ‘Legal Highs’ 4-MMC and 4-MEC by Spectroelectrochemistry: Simultaneous Cyclic Voltammetry and In Situ Surface-Enhanced Raman Spectroscopy
(2021-12-31)The synthetic cathinones mephedrone (4-MMC) and 4-methylethcathinone (4-MEC) are two designer drugs that represent the rise and fall effect of this drug category within the stimulants market and are still available in ... -
Rapid diversification of the Variable Seedeater superspecies complex despite widespread gene flow
(2022)Disentangling the evolutionary relationships of rapidly radiating clades is often challenging because of low genetic differentiation and potentially high levels of gene flow among diverging taxa. The genus Sporophila ... -
Rapid evolution of a floral trait following acquisition of novel pollinators
(2021-04)1. Changes in the pollinator assemblage visiting a plant can have consequences for reproductive success and floral evolution. We studied a recent plant trans-continental range expansion to test whether the acquisition of ... -
Rapid shift in microbial community structure in a neutral hydrothermal hot spring from Costa Rica
(2020)In this work, we characterize the geochemistry and microbial community of Bajo las Peñas, a neutral (pH 6.5-7.4), hot spring (T = 62.0-68.0°C) located near Turrialba Volcano, Costa Rica. The microbiota at its two sources ... -
Rasgos de los forófitos de Guazuma ulmifolia y Samanea saman y su influencia en la distribución espacial, abundancia y diversidad de plantas epífitas
(2021)Los rasgos de la corteza en los forófitos influyen en el establecimiento y la distribución espacial de plantas epífitas. Ante esto, en el campus de la Universidad Técnica Nacional, sede Atenas, Costa Rica, se evaluó la ... -
Rasgos morfológicos alrededor de la Isla del Coco y de sus montes submarinos vecinos, Pacífico de Costa Rica
(2012-09)The UNESCO GEBCO-08 bathymetric data was used to study the marine provinces around Isla del Coco. Seamounts with depths of less than 1000m from the sea surface were analyzed. Seamounts southward, southeastward and westward ... -
Reacciones del 2,2´-Tio-benzimidazol con Sulfato de Dimetilo
(1979)Se efectuó la reacción del 2,2´-tiobis-benzimidazol con el sulfato de dimetilo por pasos. Se comprobó la formación de: 1,1´-dimetil-2,2´-tiobis-benzimidazol (2) y del diperclorato del 1,1´,3,3´-tetrametil-2,2´-tiobisbenz ... -
Reacción del Oxido de Etileno con Clorhidratos de Aminoácidos
(1978)Se estudió la reacción del óxido de etileno con clorhidratos de aminoácidos a bajas temperaturas. Esta reacción conduce a la obtención de los aminoácidos libres. Se probó la eficiencia de este nuevo método de purificación ... -
Reactive Intermediates in the Photolysis of Furan, Thiophene and Pyrrole: The Dewar and the Ring Contraction forms
(1985-07-14)Five-member aromatic heterocycles have been known to undergo scrambling of the ring atoms upon photolysis. These reactions are characterized by their selectivity and several mechanisms have been proposed involving the ...