Browsing Ciencias básicas by Title
Now showing items 1227-1246 of 1562
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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), ... -
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 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 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 ... -
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 ... -
Reactivity and structure of derivatives of 2-hydroxy-1,4-naphthoquinone (lawsone)
(2007-11)The structures of two derivatives of 2-hydroxy-1,4-naphthoquinone (lawsone) are examined using the density functional theory (DFT) hybrid functional B3LYP. Using the optimized structure of lawsone acetate, the reactivity ... -
Recent Eurasian river discharge to the Arctic Ocean in the context of longer-term dendrohydrological records
(2007-12-29)Mapped correlations between annual discharges (AD 1938–1990) of the major Eurasian rivers entering the Arctic Ocean (Severnaya Dvina, Pechora, Ob', Yenisey, Lena, and Kolyma) demonstrate a positive relationship between ... -
Recent origin and rapid speciation of Neotropical orchids in the world's richest plant biodiversity hotspot
(2017)The Andean mountains of South America are the most species‐rich biodiversity hotspot worldwide with c. 15% of the world's plant species, in only 1% of the world's land surface. Orchids are a key element of the Andean flora, ... -
Recolecta de artrópodos para prospección de la biodiversidad en el Área de Conservación Guanacaste, Costa Rica
(Revista de Biología Tropical 52(1): 119-132, 2004, 2004)This study describes the results and collection practices for obtaining arthropod samples to be studied as potential sources of new medicines in a bioprospecting effort. From 1994 to 1998, 1800 arthropod samples of 6-10 g ... -
Recomendaciones y guías específicas para la disminución del impacto de las inundaciones en el cultivo de caña de azúcar en la Zona Norte (Orange Walk y Corozal) de Belice
(2019)Entre las actividades productivas del país de Belice está la industria de caña de azúcar. Esta industria, además de aportar al crecimiento del país también contribuye a la mayoría de la población en la zona norte del país ... -
Record of massive upwellings from the Pacific large low shear velocity province
(2016)Large igneous provinces, as the surface expression of deep mantle processes, play a key role in the evolution of the planet. Here we analyse the geochemical record and timing of the Pacific Ocean Large Igneous Provinces ... -
Recuento de la sismicidad en Costa Rica durante el 2019
(2020)Durante el 2019, la Red Sismológica Nacional (RSN: UCR-ICE) localizó 4602 sismos. De estos, 252 eventos (~5,5%) fueron sentidos por la población, incluyendo 24 sismos relevantes con magnitudes (Mw) entre 5,0 y 6,6. La ... -
Los Recursos Hídricos en Costa Rica: un enfoque estratégico
(2012-03)En este documento se presenta un diagnóstico del estado de los recursos hídricos terrestres de la República de Costa Rica (CR). En comparación a una gran cantidad de países del mundo, CR tiene una amplia disponibilidad ... -
Rediscovering the value of families for psychiatric genetics research
(2018-06-28)As it is likely that both common and rare genetic variation are important for complex disease risk, studies that examine the full range of the allelic frequency distribution should be utilized to dissect the genetic ... -
Reduced activity of Arabidopsis chromosome-cohesion regulator gene CTF7/ECO1 alters cytosine methylation status and retrotransposon expression
(2015-05-01)Multicellular organisms such as higher plants require timely regulation of DNA replication and cell division to grow and develop. Recent work in Arabidopsis has shown that chromosome segregation during meiosis and mitosis ... -
Reef flattening effects on total richness and species responses in the Caribbean
(2015-09-06)1. There has been ongoing flattening of Caribbean coral reefs with the loss of habitat having severe implications for these systems. Complexity and its structural components are important to fish species richness and ...