Browsing Facultad de Ciencias Exactas y Naturales by Title
Now showing items 1750-1769 of 2540
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Nanochitin: Chemistry, Structure, Assembly, and Applications
(ACS Publications, 2022)Chitin, a fascinating biopolymer found in living organisms, fulfills current demands of availability, sustainability, biocompatibility, biodegradability, functionality, and renewability. A feature of chitin is its ability ... -
Nanofibrilación de celulosa extraída a partir del rastrojo de la piña (Ananas comosus)
(Universidad Nacional (Costa Rica), 2021)El sector agroindustrial ha tenido un crecimiento considerable en Costa Rica durante los últimos años alcanzando los primeros lugares en los productos de mayor exportación, ejemplos de esto son la piña y el banano, estas ... -
Nanopartículas de quitosano como sistema de liberación controlada principios activos
(Universidad Nacional (Costa Rica), 2011-02)Los fármacos constituyen una herramienta básica de la medicina para el tratamiento de enfermedades y afecciones en los organismos. Sin embargo, la dosificación muchos medicamentos de uso común acarrear desventajas como ... -
Natalidad de Chelydra serpentina (Testudines: Chelydridae) en Costa Rica
(Universidad de Costa Rica, 1996)Three Chelydra serpentina nests were monitored from September through October 1993. Maximum natality was 92% (mean 33.73%) and seemed to be associated with high temperature potasium and a moderate concentration of calcium ... -
National Inventory of Mercury Release into Different Environmental Sectors Estimated by United Nations Environment Programme (UNEP) Toolkit in Costa Rica
(United Nations Environment Programme (UNEP) Toolkit, 2017)This paper summarizes the national inventory of mercury released into all environmental sectors (air, water, land, impurity in products, general wastes and sector specific treatment/disposal) for the year 2008 in the country ... -
Nations work together to size up Caribbean tsunami hazards
(AGU.ORG, 2018-10-04)El Caribe es conocido por sus playas tropicales y centros de surf, pero no está exento de terremotos y tsunamis. Durante los últimos 500 años, esta región puede haber estado expuesta a aproximadamente 100 tsunamis, de los ... -
Neighborhood structure influences the convergence in light capture efficiency and carbon gain: An architectural approach for cloud forest shrubs
(Tree Physiology vol.36 no.6 712-724 2016, 2016-03-24)Although plant competition is recognized as a fundamental factor that limits survival and species coexistence, its relative importance on light capture efficiency and carbon gain is not well understood. Here, we propose a ... -
Neighbourhood structure and light availability influence the variations in plant design of shrubs in two cloud forests of different successional status
(Annals of Botany, 2016-07)Background and Aims Plant design refers to the construction of the plant body or its constituent parts in terms of form and function. Although neighbourhood structure is recognized as a factor that limits plant survival ... -
Nematode assemblages in four ecosystems of Parque Nacional del Agua, Costa Rica
(Elsevier (Países Bajos), 2022)The soil nematode fauna of five locations situated in Parque Nacional del Agua (PNA) in Costa Rica is characterized and analyzed. Four ecosystems were sampled in each location: primary (undisturbed) forest, secondary (naturally ... -
Neotropical flowering epiphyte diversity: local composition and geographic affinities
(Universidad Nacional, Costa Rica, 2013)Worldwide, the highest diversity of vascular epiphytic plants resides in the Neotropics. The general pattern of taxonomic composition of the neotropical epiphytic flora has been described, but information regarding the ... -
Nesting ecology of East Pacific green turtles at Playa Cabuyal, Gulf of Papagayo, Costa Rica
(2014-07)East Pacific green turtles (Chelonia mydas), often referred to as black turtles, are smaller and exhibit a lower reproductive output than other populations of green turtles in the Atlantic, Indian and Western Pacific Oceans. ... -
Neutralización del efceto hemorrágico inducido por veneno Bothrops asper (Serpentes: Viperidae) por extractos de las plantas tropicales
(Universidad Nacional (Costa Rica), 1999)Organic extracts representing 48 species included in 30 families of Costa Rican tropical plants were evaluated for their hability to neutralize hemorrhagic acfivity lnduced by the venom of the snake Bothrops aspero Abioassay ... -
New advances in the method validation, extraction methods and measurement uncertainty for the determination of water-soluble hexavalent chromium in hydraulic cemen
(Elsevier, 2021)The quantification of Cr (VI) in the cement matrix is highly important, given the possibility of suffering illnesses including dermatitis, induced nasal carcinoma, and DNA damage produced by inhalation of and/or direct ... -
New advances in the method validation, extraction methods and measurement uncertainty for the determination of water-soluble hexavalent chromium in hydraulic cement
(Elsevier Ltd, 2021-04-20)The quantification of Cr (VI) in the cement matrix is highly important, given the possibility of suffering illnesses including dermatitis, induced nasal carcinoma, and DNA damage produced by inhalation of and/or direct ... -
New records of historical tsunamis obtained from Costa Rican newspapers
(American Geophysical Union, 2020-12-14)Costa Rica has few records of historical tsunamis, due to traditionally low populated coasts and moderate tsunami potential, among other reasons. As part of the writing of the first tsunami catalog of Costa Rica, the authors ... -
New records of Pteris (Pteridaceae) from the Neotropics
(Universidad Nacional (Costa Rica), 2014)As a result of studies on neotropical Pteris L., we report new records of Pteris albertiae and P. longifoliafrom Costa Rica; P. longipetiolulata from Costa Rica, Panama, Peru, Bolivia, and Venezuela; and P. muricatopedatafrom ... -
New records of snipe eels (Anguilliformes: Nemichthyidae) from the Pacific coast of lower Central America
(Marine Biodiversity Records vol.9 no.1 1-6 2016, 2016)Background: New records of occurrence of two snipe eels (Avocettina bowersii and Nemichthys scolopaceus), poorly known for the Pacific coast of Costa Rica and Panama are herein reported. Results: Specimens, 45 in total (28 ... -
New records, validated name, and redefinition in Azolla (Salviniaceae, Pteridophyta) from Costa Rica
(Universidad de Antioquia (Colombia), 2024)In studies of herbarium specimens and living material, we observed that several species in the genus Azolla Lam. are present in different wetlands of Costa Rica, which instigated the search for applicable names of each ... -
New sighting of seagrasses in the Eastern Tropical Pacific (Bahía Potrero, Costa Rica)
(Elsevier B.V., 2018-07-22)Seagrass meadows provide a multitude of ecosystem services, yet they are currently threatened and declining worldwide due to anthropogenic impacts. Current knowledge of seagrass presence in the Eastern Tropical Pacific ... -
New species and records of Cloeodes Traver, 1938 (Ephemeroptera, Baetidae) from Costa Rica
(Pensoft (Bulgaria), 2020)The nymph of Cloeodes danta sp. nov. is described from male and female nymphs collected from highland streams in the Caribbean Slope of the Costa Rica Central Volcanic Mountain Range. Adults are unknown. In addition, C. ...