Browsing Artículos científicos by Title
Now showing items 503-522 of 555
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The effect of high rearing densities on the growth of juveniles of the cichlid, cichlasoma managuense
(Universidad Nacional, Costa Rica, 1992-01-01)The effect of high density culture on the growth of juvenile jaguar cichlids was investigated. Mean growth rate decreased with density, while the growth rate of the largest fishes was not affected. Reduction in mean growth ... -
The effect of Ibuprofen on female and male reproduction of the open thelyca marine shrimp, Litopenaeus
(Aquaculture Research, 2013-03-11)A research was designed to explore the effect of ibuprofen (IBU) as an intervening agent for prostaglandin biosynthesis on male and female reproduction of three species of Litopenaeus. Ovarian maturation was studied in L. ... -
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 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 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 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 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 ... -
Thermal niche breadth and their relationship with sturnira bat species diversification
(Elsevier (Países Bajos), 2023-10)The interaction between climatic conditions and the ability of organisms to maintain homeostasis regulates the distribution of species on the planet. However, its influence on macroevolutionary dynamics is not well ... -
Thoracic nerve cord - ganglia recognition in intraspecific and interspecific transplants in the white shrimp, Penaeus (Litopenaeus) vannamei
(Science Direct, 2009-03)The recognition response of Penaeus (Litopenaeus) vannamei against thoracic nerve cord–ganglia transplants from three species of Penaeidae: P. vannamei, P. (Litopenaeus) stylirostris, and Trachypenaeus byrdi, and one species ... -
Three New Species and New Records of Dennstaedtia Bernh. from Mesoamerica
(Universidad Nacional, Costa Rica, 2018)Navarrete & Øllgaard [1] indicated the presence of a “C” group within Dennstaedtia Bernh. that contains D. obtusifolia (Willd.) T. Moore, which is the type material of the genus Patania C. Presl and indicated that it ... -
Three New Species of Ferns (Pteridophyta) from Mesoamerica
(Universidad Nacional (Costa Rica), 2017-05-25)In this research three new species of ferns of the Polypodiales Order are described: Ctenitis leonii A. Rojas, Elaphoglossum karinae A. Rojas and Pecluma celaquensis A. Rojas. Ctenitis leonii is characterized by its apical ... -
Three new species ofElaphoglossum Schott ex J. Sm. (Dryopteridaceae) from the pacific of Costa Rica
(Universidad Nacional (Costa Rica), 2017-12)In this paper three new species of Elaphoglossum Schott ex J. Sm., are described and illustrated, located on the pacific slope of Cordillera de Talamanca and Cerro Caraigres (Cerro Dragón), Costa Rica. The new ... -
Tourism sustainability in a Protected Area: Case Loreto Bay National Park
(Universidad Nacional (Costa Rica), 2021-11-21)El objetivo de este estudio fue evaluar la tendencia del desempeño del turismo sostenible en el Parque Nacional Bahía de Loreto en Baja California Sur, México y sus áreas de influencia, cubriendo el período 2007-2017. ... -
Transversalidad y valores: una propuesta metodológica para incorporarlos en los Programas de estudio de Ciencias y Biología
(Universidad Nacional, Costa Rica, 2004)La creciente crisis social producto de la deficiencia y carencia de valores ha generado un deterioro de la dignidad humana, del orden social y del ambiente entre otras cosas. Es en este punto en donde surge la necesidad ... -
Treasured exceptions: association of morphoanatomical leaf traits with cup quality of Coffea arabica L. cv. “Catuaí ”
(Food Research International, 2021-01-05)The morphoanatomical characteristics of leaves were associated with altitude, hillside, and the cup quality of coffee produced in the Matas de Minas region. Although the small magnitude, there are correlations between cup ... -
Tres especies nuevas de Hymenophyllum Sm. (Hymenophyllaceae, Pteridophyta) para Costa Rica y Colombia
(Universidad Nacional (Costa Rica), 2017-12)En este artículo tres especies nuevas deHymenophyllum Sm. son descritas e ilustradas para Costa Rica y Colombia: H. densipilosum A. Rojas, H. hastatumA. Rojas e H. multicristatum A. Rojas. Todas las especies aquí descritas ...