Browsing Artículos científicos by Title
Now showing items 189-208 of 555
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Ecological Integrity Impairment and Habitat Fragmentation for Neotropical Macroinvertebrate Communities in an Agricultural Stream
(Multidisciplinary Digital Publishing Institute (MDPI) (Suiza), 2022)The Volcán River watershed in the south Pacific of Costa Rica comprises forests, small urban settlements, cattle fields, and intensive agriculture (mostly pineapple and sugarcane). The ecological integrity and quality ... -
Ecología de Larvas de peces: I. Ecología alimenticia
(UNICIENCIA, 1984-07-01)RESUMEN Estudio de huevos y estados larvales de peces marinos ya que existen como una simbiosis sobre los primeros estadios de vida del pez. Su importancia recae en la aplicación a través de los estudios sobre taxonomía, ... -
Ecology and management of the invasive lionfish Pterois volitans/miles complex (Perciformes: Scorpaenidae) in Southern Costa Rica--
(Universidad Nacional (Costa Rica), 2015-03)Invasive species alter ecosystem integrity and functioning and are considered one of the major threats to biodiversity on a global scale. The indopacific lionfish (Pterois volitans [Linnaeus, 1758] / miles [Bennet, 1882] ... -
Efecto de la fitasa en el aprovechamiento del fósforo en dietas para tilapia (Oreochromis niloticus). Resultados preliminares.
(UNICIENCIA, 2001-06-01)Con el fin de evaluar si mediante la adición de la enzima fitasa se puede aumentar la cantidad de fósforo (P) disponible en dietas comerciales de tilapia (Oreochromis niloticus) y con ello reducir su excreción al medio, ... -
Efecto de la temperatura sobre el crecimiento de juveniles del guapote lagunero (Parachromis dovii)
(Universidad Nacional (Costa Rica), 2001)En animales exotermos, como los peces, la temperatura corporal varía con la temperatura ambiental. En condiciones de laboratorio estos animales tienden a escoger una temperatura preferencial que coincide aproximadamente ... -
Efecto de las descargas del emisario submarino de aguas residuales de la ciudad de Limón sobre la calidad del agua, abundancia y diversidad del fitoplancton en los alrededores de isla Uvita, Costa Rica
(Universidad Nacional, 2020-12-09)Con el objetivo de evaluar la posible afectación del emisario submarino en la ciudad de Limón, sobre el medio marino circundante, se establecieron 6 estaciones de muestreo, 4 de ellas cercanas a la zona de desfogue y 2 ... -
Efecto del probiótico Bacillus subtilis sobre el crecimiento y alimentación de tilapia (Oreochromis niloticus) y langostino (Macrobrachium rosenbergii) en laboratorio
(Revista de Biología Tropical, 2004-12-01)Effect of the probiotic Bacillus subtilis on the growth and food utilization of tilapia (Oreochromis niloticus) and prawn (Macrobrachium rosenbergii) under laboratory conditions. Three experiments were conducted to analyze ... -
Efectos de El Niño y La Niña sobre el comportamiento del microfitoplancton marino y las variables fisicoquímicas durante el 2008 a 2010 en el Golfo de Nicoya, Costa Rica
(Universidad Nacional (Costa Rica), 2014-12)El Niño 2009 fue responsable de una estación lluviosa de baja intensidad y de valores promedios anuales de temperatura del agua, sólidos totales, salinidad y oxígeno disuelto más altos. Las densidades medias de diatomeas ... -
Effect of dietary lipid level on protein utilization and the size and proximate composition of body compartments of Colossoma macropomum (Cuvier)
(Wageningen Agricultural University, 1997)Juvenile Colossoma macropomum were fed ad libitum diets containing either 30% or 40% protein, while the dietary lipid level varied between 5% and 20%. Growth and protein utilization efficiency increased with the dietary ... -
Effect of different chemical treatments on nutritional and antinutritional properties of coffee pulp
(Elsevier, 2002)Different chemical treatments were tested to improve the nutritional value of coffee pulp (CoP): (1) alkali, NaOH solutions of 5 and 10% for 24 and 48 h; (2) a combination of acid and alkali, with first a treatment with ... -
Effect of feeding level on feed losses and feed utilization of soya and fish meal diets in Colossoma macropomum (Cuvier)
(Wageningen Agricultural University, 1997)Juvenile, 1-g Colossoma macropomum (Cuvier) were fed two different diets: one with fish meal and another with soya meal as the main dietary protein source. Both diets were provided at ad libitum feeding level, and at two ... -
Effect of metal concentration on growth and luminescence of luminous bacteria straims isolated from golfo de Nicoya, Costa Rica
(Universidad Nacional (Costa Rica), 2021-01)Luminescence in bacteria is catalyzed by luciferase. When these microorganisms are exposed to toxic substances, the bioluminescent enzyme system can be inhibited. The objective of this study was to analyze the potential ... -
Effect of organic nitrogen and carbon mineralization on sediment organic matter accumulation in fish ponds
(Aquaculture Research, 2005-07-01)In aquaculture, ponds with high loads of organic inputs, organic matter accumulates at the bottom over time. Uneaten feed, senescent phytoplankton and faeces are the principal sources of accumulated material, but quanti¢cations ... -
Effect of two cytokinins and a growth inhibitor on the in vitro tuberization of two genotypes of Solanum tuberosum L. cvs. Atlantic and Alpha
(Universidad Nacional (Costa Rica), 2019-07-31)This investigation was carried out to evaluate the effect of two cytokinins: 6-benzilaminopurine (BAP) (6.5 mg l-1) and kinetin (K) (2.5 mg l-1), as well as the growth inhibitor abscisic acid (ABA) (1.0 mg l-1) on the in ... -
Effects of androgenic gland ablation on growth, sexual characters and spermatogenesis of the white shrimp, Litopenaeus vannamei (Decapoda: Penaeidae) males
(Aquaculture Research Vol.47 No.9 2768-2777, 2015-03-10)This research was implemented to study the effects of androgenic gland ablation in the white shrimp Litopenaeus vannamei to explore sex reversal potential as an alternative technology for monosex female mariculture based ... -
Effects Of Radio Transmitter Burdening On Locomotor Ability And Survival Of Iguana Hatchlings
(Allen Press, 2009)We performed a two-part experiment in 2007 and 2008 to investigate the effects of externally affixed radio transmitters on the locomotor performance and survival of green iguana {Iguana iguana) hatchlings. Using sprint ... -
Effects of the protein: energy ratio in isocaloric diets on the growth of Cichlasoma managuense (Gunther 1869)
(Wiley & Sons, 1994)A feeding experiment was conducted to evaluate the growth of tiger guapote, Cichlasoma managuense (Gunther), fed on isocaloric diets with varying proteinxnergy ratios. The relative metabolic growth rate increased with ... -
Efficacy of calcein and Coomassie Blue dyeing of shell growing-edges and micro growth-bands: Ageing juvenile of Pinctada mazatlanica(Pterioida: Pteriidae)
(Universidad de Costa Rica, 2014)Age validation is the first step to determine shellfish species age determination. This information is vital for different inferential models used in marine ecosystem management activities. In spite that various validation ... -
Ensamblaje de insectos con actividad nocturna en dos arrozales de los Llanos Noroccidentales de Venezuela
(Museo de Biología de la Universidad del Zulia, 2020-06-30)In order to contribute to our knowledge on assemblages of nocturnal insects associated with rice crops in Venezuela, two rice fields located in Acarigua and Turén, Portuguesa State, were studied. Sampling was carried out ... -
La enseñanza de la nutrición a nivel de secundaria utilizando el tema transversal “educación para la salud” desde un enfoque útil para la vida
(Universidad Nacional (Costa Rica), 2015)En este artículo se presentan los resultados de una investigación cuyo objeto de estudio fue determinar cómo está el personal docente de ciencias, de 4 colegios pertenecientes a la Dirección Regional de San José, el tema ...