Browsing Facultad de Ciencias Exactas y Naturales by Title
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Ultraestructura de la glándula androgénica, espermatogénesisy oogénesis de camarones marinos (Decapoda: Penaeidae)
(Universidad de Costa Rica (Costa Rica), 1994-08-01)Se describe la glándula androgénica de Penaeus vannamei y P. Stylirostris (camarones thelycum abiertos). La glándula es una hebra celular que aparece asociada a los conductos deferentes desde la región proximal de la ampolla ... -
Ultrastructural demonstration of the model of Litopenaeus vannamei (Crustacea, Penaeidae) male sexual maturation and spermatozoal capacitation
(Invertebrate Reproduction and Development Vol.61 No.1, 2016-10-13)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 ... -
Understanding failures through the lifetime of a top-level supercomputer
(Academic Press Inc., 2021-04-20)High performance computing systems are required to solve grand challenges in many scientific disciplines. These systems assemble many components to be powerful enough for solving extremely complex problems. An inherent ... -
Understanding Space Weather: Solar Cycles and Magnetic Rossby Waves
(Universidad Nacional de Costa Rica, 2019-07-31)El objetivo de esta investigación es explorar si existe una relación entre las ondas magnéticas de Rossby rápidas o lentas y ciertas observaciones de la actividad solar de largo y muy largo plazo (meses, ... -
Understory bat roosts, availability and occupation patterns in a Neotropical rainforest of Costa Rica
(Revista de Biología Tropical, 2016-07-03)The strong link between bats and their roosts is widely recognized as being particularly significant. Despite this, roosting ecology of bats is poorly understood and much of the basic information is still unknown. In this ... -
Unexplored Character Diversity in Onychophora (Velvet Worms): A Comparative Study of Three Peripatid Species
(Sars International Centre for Marine Molecular Biology, Norway, 2012-12-17)Low character variation among onychophoran species has been an obstacle for taxonomic and phylogenetic studies in the past, however we have identified a number of new and informative characters using morphological, molecular, ... -
Uniciencia journal adopts the continuous publication model
(Universidad Nacional (Costa Rica), 2021) -
Unión interuniversitaria para el fortalecimiento de las Olimpiadas Costarricenses de Ciencias Biológicas como proceso de formación de los futuros profesionales en el área de las ciencias y la actualización de los conocimientos de los y las docentes de secundaria sobre biología
(Universidad Estatal a Distancia (UNED) (Costa Rica), 2015-04-28)Las Olimpiadas Costarricenses de Ciencias Biológicas promueven el estudio activo, participativo y significativo de las ciencias biológicas a nivel de la enseñanza media y preuniversitaria y potencian el nivel cognitivo ... -
La unión y formación de poros de las actinoporinas están determinadas por las propiedades fisicoquímicas de la membrana
(Academia de Ciencias de Cuba (Cuba), 2022)Introducción. Las actinoporinas (AP) son proteínas formadoras de poro (PFP) que se asocian a membranas conduciendo a la muerte celular. Sticholysinas I y II (St, StI/II) se encuentran entre las AP más potentes descritas ... -
Unveiling the hidden bat diversity of a neotropical montane forest
(PLOS ONE Vol.11 No.10, 2016-10-05)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, ... -
Usage and limitations of free and open-source software in Costa Rican local governments
(IEEE Explore, 2013-10-07)This paper presents results about the use and barriers that face free and open source software in the local governments in Costa Rica. Through an electronic survey, information was gathered from such governments, allowing ... -
Use and perception of open source by students of the national university in non IT careers
(Institute of Electrical and Electronics Engineers Inc., 2019-08-20)This paper discloses some initiatives that have been carried out by the National University with open source and an exploratory study of the use and perception of a part of the students of the National University that are ... -
Use and Perception of Open Source by Students of the National University in non IT Careers
(Instituto of Electrical and Electronica Engineers (IEEE), 2019)This paper discloses some initiatives that have been carried out by the National University with open source and an exploratory study of the use and perception of a part of the students of the National University that are ... -
Use of food and spatial resources by two frogs of the genus Dendropsophus (anura: Hylidae) from La Selva, Costa Rica
(Universidade de Sao Paulo, 2012-06)Differences in the use of resources by similar species have been related to a reduction in the interspecific competition that allows coexistence. Also, other factors, such as high availability of resources in the environment, ... -
Using Sniffer4D and SnifferV portable gas detectors for UAS monitoring of degassing at the Turrialba Volcano Costa Rica
(Advanced UAV, 2023)Since the completion of the first Sniffer UAS payload research article titled; Using UAS with Sniffer4D Payload to Document Volcanic Gas Emissions for Volcanic Surveillance: In this study the UAS system deployed carried ... -
Using UAS with Sniffer4D payload to document volcanic gas emissions for volcanic surveillance
(Advanced UAV, 2022)A consistent volcanic monitoring program is crucial to the safety of the population and the efficiency of the nation. Costa Rica´s National Commission for Risk Prevention the CNE helps manage this responsibility. The ... -
Using visible-near-infrared spectroscopy to classify lichens at a Neotropical Dry Forest
(Elsevier B.V., 2020-04)The optical properties of lichens have been traditionally explored in the context of geological mapping where the encrustation of lichens on rocks may influence the detection of minerals of interest. As of today, few studies ... -
Uso alternativo de excedentes agroindustriales en la formulación de fertilizantes orgánicos foliares
(Universidad Nacional (Costa Rica), 2003)Debido a la reciente demanda de alimentos a nivel mundial provocado por la explosión demográfica que ha dado en las últimas décadas, la calidad de plaguicidas y fertilizantes químicos empleados ha aumentado a un ritmo ... -
Uso alternativo de residuos de caña de azúcar obtención de espumas rígidas de poliuretano
(Universidad Nacional (Costa Rica), 2004)En este trabajo se realizó un estudio para comprobar la efectiva sustitución parcial de los reactivos de uso común en la elaboración de espumas rígidas de poliuretano, por materiales lignocelulósicos provenientes de la ... -
Uso de algunos constructos del modelo de Competencias y Conocimientos Didáctico-Matemático para el estudio de informes de práctica de futuros profesores de matemáticas.
(Comité Interamericano de Educación Matemática, CIAEM, 2019-05)El Modelo de Competencias y Conocimientos Didáctico-Matemático ha permitido el abordaje de problemas de la didáctica de las matemáticas y en particular, el análisis didáctico. El objetivo de este taller es utilizar algunos ...