Browsing Facultad de Ciencias Exactas y Naturales by Title
Now showing items 2457-2476 of 2615
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The first gynandromorph of the Neotropical bee Megalopta amoena (Spinola, 1853) (Halictidae) with notes on its circadian rhythm
(Pensoft Publishers, 2020-04-27)Gynandromorphy is an anomaly that results in an organism phenotypically expressing both male and female characteristics. Here we describe the first gynandromorph of the bee species Megalopta amoena (Spinola, 1853) (Halictidae, ... -
The geographic distribution of Costa Rican velvet worms (Onychophora: Peripatidae)
(Revista de Biologia Tropical vol.64 no.4 1401-1414 2016, 2016-06-06)Velvet worms, “peripatus” or onychophorans, are “living fossils” that were geographically widespread in Cambrian seas but now occur exclusively on terrestrial habitats. The only extant species studied in some detail are ... -
The growth of juvenile jaguar guapote (Cichlasoma managuense) fed diets with different carbohydrate levels
(Universidad Nacional (Costa Rica), 1995-06-27)Se evaluó el crecimiento de juveniles del guapote tigre (Cichlasoma managuense) alimentado con dietas isocalóricas conteniendo niveles de carbohidrato del 11 al 36 por ciento. El experimento se realizó en un sistema de ... -
The histological structure of the androgenic gland and cellular cord of the male reproductive system of adult litopenaeus and rimapenaeus byrdi
(2012-05-01)The current knowledge of the precise extension and location of the androgenic gland (AG) in the genera Litopenaeus and Rimapenaeus is partial. Therefore, we analyzed the complete structure of the AG and cellular cord ... -
The Influence of IoT Simulation in the Learning Process: A Case Study
(Association for Computing Machinery, 2020-03-28)Internet of things (IoT) is a relatively novel technology which provides connection between things. It was presented for the first time by Kevin Ashton in 90´s.The software and hardware development of IoT is not growing ... -
The interplay between irrigation and fruiting on branch growth and mortality, gas exchange and water relations of coffee trees
(Oxford University Press, 2021)The overall coordination between gas exchanges and plant hydraulics may be affected by soil water availability and source-to-sink relationships. Here we evaluated how branch growth and mortality, leaf gas exchange and ... -
The magnetic dispersion
(Editorial de la Universidad Nacional, 1985-01-01)We present a study of the elastic scattering of an electron in a constant homogeneous magnetic field. The dependency of the cross section on the electron spin orientation is given. If the spin polarization is along or ... -
The manufacture and properties of oil palm and pineapple leaf fiberboard panels
(WIT Transactions on Ecology and the Environment, 2014)Particleboards were manufactured from oil palm fruit, the oil palm mesocarp fiber of Elaeis guineensis, the leaves of pineapple (Ananas comosus) and the sawdust from three fast-growing species of trees (Gmelina arborea, ... -
The opossum and other didelphids in the cultures of Costa Rican society and indigenous peoples: an approach to ecology and conservation
(Cold Spring Harbor Laboratory (Estados Unidos), 2024)The opossum Didelphis marsupialis, commonly referred to as the zorro pelón in Costa Rica, is a marsupial that holds significant representation in both Costa Rican and indigenous cultures, such as the Talamanca natives. ... -
The persistent embrace of onychophorans: What determines copulation duration in velvet worms?
(Universidad de Costa Rica (Costa Rica), 2019)In the only onychophorans mating that has been photographed, instead of fleeing, the couple remained together despite being manipulated. Why? The duration of copulation in onychophoran sis possibly controlled by the female, ... -
The polynucleotide kinase 3′-phosphatase gene (PNKP) is involved in Charcot-Marie-Tooth disease (CMT2B2) previously related to MED25
(Springer, 2018-07-24)Charcot-Marie-Tooth disease (CMT) represents a heterogeneous group of hereditary peripheral neuropathies. We previously reported a CMT locus on chromosome 19q13.3 segregating with the disease in a large Costa Rican family ... -
The proteolytic digestive activity and growth during ontogeny of Parachromis dovii larvae (Pisces: Cichlidae) using two feeding protocols
(2014)Se evaluó la actividad proteolítica digestiva y el crecimiento de larvas de Parachromis dovii durante la ontogenia en un sistema de recirculación utilizando dos estrategias de alimentación durante un período de 28 días. ... -
The regionalization of a university project of educational robotics to help Costa Rican youth to avoid drug consumption
(Institute of Electrical and Electronics Engineers Inc., 2019)The following article presents the experience of the regionalization of the Training of Trainers in Robotics project in Schools in vulnerable areas of Costa Rica to the different regions outside the Greater Metropolitan ... -
The relationship between humidity, light and the activity pattern of a velvet worm, Epiperipatus sp. (Onychophora: Peripatidae), from Bahía Drake, South Pacific of Costa Rica
(Instituto Internacional de Ecología (Brasil), 2018-10-31)Even though the Onychophora represent a whole phylum, observations of their activity pattern in nature are almost non-existent. Here we report on the relationship between humidity and light and activity pattern of a new ... -
The relationship between information and communication technology and productivity in Costa Rican companies
(IEEE Explore, 2012-10-01)This paper presents the results of a research aimed at studying the effect of information and communications technology (ICT) on productivity, using the data of the Costa Rican innovation survey 2008. The results obtained ... -
The relationship between perch type and aggressive behavior in the lizard Norops polylepis (Squamata: Dactyloidae)
(Universidad de Sao Paulo, 2015)The intensity of aggression against intruders by owners of a territory has been related to the type of resources available to an individual within its territory. The influence of perch-site characteristics on aggressive ... -
The rip current hazard in Costa Rica
(2015-01-31)Deaths from rip currents are a major hazard on global beaches, but few data are available at a national scale to support the development of appropriate intervention programs. Analysis of data from the Judicial Investigation ... -
The rock coast of South and Central America
(Geological Society Memoirs 2014, 2014-07)The great variety of climatic conditions, tidal ranges and wave regimes of South and Central America act on a complex geology and tectonic framework. Many of the rock and cliffed coasts of South America are strongly ... -
The structure and function of dry weather mangrove on the Pacific Coast of Central America, with emphasis on Avicennia bicolor forests
(Estuaries Research Federation, 2013)Mangrove forests along the Pacific Coast of Central America cover around 4,000 km2. Most of this coast is occupied with tropical dry forest mangroves where basal areas range between 6 and 20 m2 ha−1 and canopy heights ... -
The Use of the Arm Circumference as a Measure to Detect Underweight in Individuals Aged 60 Years or Older Living in Costa Rica
(Universidad Nacional (Costa Rica), 2023-09-01)[Objective]: This investigation focuses on the association between arm circumference and body mass index, and the estimation of cutoff values of this arm measurement for identifying low weight ...