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DIALNET OAI Articles (561,989 recursos)
Dialnet (Difusión de Alertas en la Red) es una plataforma de recursos y servicios documentales, cuyo objetivo fundamental se centra en mejorar la visibilidad y el acceso a la literatura científica hispana a través de Internet.

Ciencias biológicas

Mostrando recursos 1 - 20 de 16,306

1. La inocuidad de las proteínas cry presentes en los alimentos transgénicos - Peña Betancourt, S. D.
At present some grains, oilseeds, fodder, hormones and enzymes used in animal production have undergone changes in its genome to contain recombinant proteins. The aim of this review is to present scientific information on the safety of Cry proteins present in GM maize (Bt11, Bt176), there is evidence of the safety of the insecticidal proteins Cry1Ab, Cry1Ac, Cry1F expressed in both events, without having been able to confirm whether the Cry proteins may develop allergies in susceptible individuals, the concentration of recombinant proteins and the herbicide glyphosate, safely secure in animal products such as meat, milk, eggs and fish that come from animals fed with alfalfa, soybean...

2. Estudio comparativo de hembras finnish landrace x merino australiano vs. Merino australiano: II. Producción de carne - Bianchi Olascoaga, Gianni; Garibotto Carton, Gustavo; Lamarca Bianchessi, Martin
The lamb production effect of 259 hogget of two teeth: 150 Finnish Landrace x Australian Merino (FLAM) vs. 109 Australian Merino (AM) mated in autumn (15/03- 17/05/2010) was studied. The live weight of the ewes in the annual cycle fluctuated between: 42.6 vs. 35.8 kg (25/12/2009) and 48.8 vs. 42.1 kg (30/11/2010), FLAM y AM; (p ≤ 0,05), respectively. Milk production estimated from 48 ± 8,2 days of lactation turned out to be independent of the genotype (58,3 vs. 56,4 g/h of milk, FLAM y AM, p>0,05; respectively), but different from FLAM hogget raising one or two lambs (43,9 vs. 66,6 kg; p≤0,05, respectively). The lambs were...

3. Efecto de los lactobacilos en la ganancia de peso de pollos de engorda - Martínez González, Juan Carlos; Legorreta Cárdenas, Rafael; Andrés Lucero, Froylan; Castillo Rodríguez, Sonia P.
The poultry industry has been affected by high feed cost; the objective was to assess the effects of Lactobacillus on the weight gain of broiler chicken in the initiation phase. The study was conducted at the Experimental Avicola Unit of Engineering and Science College. Broiler chicken (100) commercial line, without sexing three days old were used. The treatments consisted in the addition of 0, 5, 10 and 15 mg of Lactobacillus per kg of food. A completely randomized design was used. There were no significant differences P > 0.05) in weight gain. The final weights per treatment were 919, 929, 964 and 930 g for treatments 0,...

4. Medidas zoométricas y crecimiento pre-destete en corderos de ovejas híbridas y carneros de la raza southdown - Larrondo Cornejo, Cristian; Bianchi Olascoaga, Gianni; Uribe Muñoz, Héctor
The aim of this study was to evaluate the effects of ram and ewe biotype on birth weight (BW), average daily gain (ADG), weaning weight (WW), body measurements, and survival to weaning (SW) of 330 lambs. Lambs were from 192 artificial inseminated hybrid ewes: ¾ Poll Dorset x Corriedale [PDC, n=47], ¾ Texel x Corriedale [TXC, n=24], ½ Finnish Landrace x Corriedale [FLC, n=24], and ½ Finnish Landrace x Australian Merino [FLM, n=97], with semen from 4 Southdown rams. Opposite to what was expected, the ram effect didn’t have an effect on any of the analyzed traits (P>0.05). On the contrary, PDC lambs had higher BW...

5. Factores que alteran la conducta de estro en ovejas de pelo sincronizadas con acetato de fluorogestona y gonadotropina de suero de yegua preñada - González Reyna, Arnoldo; Andrés Lucero, Froylan; Briones Encinia, Florencio; Vázquez Armijo, José Fernando; Limas Martínez, Andrés Gilberto; Martínez González, Juan Carlos
An experiment was conducted, at Ganadera Mirasol, Guémez, in the center region of the state of Tamaulipas, Mexico. The effects of some environmental factors that affect the performance estrous, were studied in hair sheep, subjected to treatment for induction/synchronization of estrus, using fluorogestone acetate (FGA) and pregnant mare serum gonadotropin (PMSG). A total of 150 females (ewes and ewelambs) was used, Blackbelly (BB=22), White Pelibuey (WP=15) and Red Pelibuey (BP=113). The ewes were treated with intravaginal sponges impregnated with 40 mg of FGA for 12 days, 24 h prior to removal of the sponge, the PMSG was administered and 24 h after injection, estrus detection initiated. The effects...

6. Primera cita del híbrido Freesia × hybrida (alba × leichtlinii) como taxón alóctono Península Ibérica - Guillot Ortiz, Daniel; Sáez, Llorenç; Puche, Carles
Se cita por primera vez de la Península Ibérica el híbrido de Freesia x hybrida (=F. alba x F. leichtlinii). Este taxón se considera invasor en Australia. Ha sido detectado en márgenes de la red viaria cerca de la localidad de Serra (Comunidad Valenciana, España).

7. Primera contribución al conocimiento de los insectos del Parque Nacional Bou Hedma de Túnez. - Ghannem, Samir; Khalloufi, Noureddine; Boumaiza, Moncef

8. Estado de la gestión municipal de los residuos sólidos en la provincia de Cartago - Soto Córdoba, Silvia M.; Gaviria Montoya, Lilliana
This paper resumes the principals results obtained by the grant EUROPEAID/126635/M/ACT/CR”, that was realized by FUNDATEC, and whose bene­ficiary was the “Federación de Municipalidades de Cartago, Costa Rica”, the Project received a funding of 74,920 euros. We work with all the Municipalities of the Cartago Province. In addition, we show the results of the interviews of social actors, visits to the recycle sites, visits of municipalities, during the years 2010, 2011 and 2012, and the review of literature. We describe the actual situation of the management of solid waste in Cartago, determinate the gene­ration rates by person and identified the...

9. Definición del proceso de elaboración de una bebida fermentada a partir de pulpa del café (broza) - Arguedas Gamboa, Patricia
Weather and soil conditions of Costa Rica give to the country the possibility of having an economy based in agricultural activities. Coffee had been for centuries the most important crop for economic and social development in Costa Rica. However, international agreements avoid coffee producers to give an attractive added value to the grain. They have to export the product as a dried grain. They get prices that depend of weather con­ditions in other countries that produce coffee. Furthermore the coffee activity produces a big quantity of agricultural residues. It is estimated that every year, around 400 000 tons of pulp...

10. Recurso Hídrico Superficial en la Cuenca del río Tempisque, Costa Rica: Escenarios de Disponibilidad y Demanda - Guzmán-Arias, Isabel
This paper describes the status of water resources availability and demand in the upper and middle Tempisque watershed projected up to 2030 and the proposed actions to start a planning process. The resource availability scenarios incorporate the modifications inwater flows due to land use and cli­mate changes; these combined effects increases the problems of water shortages during the dry season. The resource demand scenarios include projections provided by the major users in the watershed, of which very few can envision growth expectations in terms of water consumption. The proposed resource planning process integrates the analysis conducted in this thesis and...

11. Vigas tipo I para la construcción civil fabricadas con madera de plantaciones de rápido crecimiento en Costa Rica - Tenorio Monge, Carolina; Moya, Róger; Carranza, Mauricio
Recently, the timber market in Costa Rica has been supplied with fast growing trees from forest planta­tions. However, there are some problems relationed to design and development of high technology products. In order to introduce the forest planta­tions woods in the market, the main objective of this study was to determinate the design stress (bending, shear and bending stiffness) from I-beams fabricated with Gmelina arborea wood using lumber for the flanges and 12 mm plywood for web. Three types of profiles were developed (24 cm, 16 cm and 10 cm in high) and two quality types (A and B). The...

12. Comparación de métodos de exposición dermal a plaguicidas en una muestra de floricultores y productores de palmito y chayote en Costa Rica - Medina Escobar, María de Lourdes; Rodríguez Zamora, María Gabriela; Zamora Rodríguez, Paula
Costa Rica exports a wide variety of agricultural products such as chayote, palm hearts, flowers and ferns. Different methods are used for pest control, including chemical based pesticides, even though they could be damaging the farmer’s health. This exploratory study, aimed to compare, in a sample of farmers from each of these crops, three different techniques for dermal exposure assessment: the algorithm quantitative approach method (AQAM), fluorescent tracer and dermal patches. From the algorithmic the intensity levels of exposure were obtained, with fluorescent tracer technique (FTT), deposition of pesticides on workers skin was estima­ted during application and with absorbent patches...

13. Pasos críticos en la estimación de pose en cámara: una evaluación usando la biblioteca LTI-LIB2 - Cabrera Quirós, Laura; Campos Gómez, Rafael; Castro Godínez, Jorge
An evaluation of camera pose estimation methods using a chessboard pattern is presented. Steps evaluated in the estimation process are landmark point detection and camera parameter estimation, due to their critical role in the entire process. The ChESS method and a custom heuristic method are compared for chessboard pattern detection.  Both methods are objectively contrasted using True Positive and False Negative criteria. Meanwhile, Zhang’s method for pose estimation based on planar surface point distribution is used as a first approach, and then refined with a nonlinear regression through the Levenberg-Marquardt algorithm. This pose estimation algorithm is evaluated through a comparison...

14. Evaluación en el agua para consumo humano de subproductos de cloración y su relación como inductores de mutagénesis (mutaciones celulares) - Montero Campos, Virginia; Chinchilla Montero, Rodrigo; Coy Herrera, Ricardo; Agüero Hernández, Ana Laura; Jiménez Antillón, Joaquín
In the chlorination process produces a series of chemical reactions between the chlorine used in the disinfection and the organic matter present in the water to be treated. The nature and concen­tration of the compounds formed, are dependent physicochemical variables of soil organic matter, which react with chlorine added products origina­ting from different compounds, are toxic, mutagenic and carcinogenic including, all together are known as chlorination byproducts (acronym SPD), which include compounds called trihalomethanes (THM’s). It was investigated the presence of these types of products in costa rican waters by the technique of solid phase microextraction (HEADSPACE / SPME Solid...

15. Esferas precolombinas de la zona sur en Costa Rica: cultura y poder en la tecnología de la piedra - De-Simone, Alexandra
This article seeks to articulate a reflection on culture and power, taking as object the Spheres produced by an ancient culture of America, in what is now the southern of Costa Rican territory. In the first part, we describe some of the symbolic dynamics of power in wich these enigmatic objects have been involved: as media spectacle, as a reinforcer of natio­nal identity, as the object of a banana community mobilization, with mention of the institutional pro­blems around archaeological heritage. In the second part, we develop a set of notes for interpretive aesthetic analysis of the spheres, using categories of...

16. Las comunidades de nematodos como indicadores ambientales - Varela Benavides, Ingrid
The use of environmental indicators is a topic of current interest. It allows us to describe the con­dition of an ecosystem and the pressures that is being subject. And at the same time indicate the effectiveness of the mitigation practices. Nematodes are among the organisms that have been studied for their potential as environmental indicators. These animals are cosmopolitan and play an impor­tant role in all ecosystems. Furthermore the nema­tode community predictably changes with the disturbances to the environment. These changes are related to indicators of ecosystems functions. There are taxa indicative of conditions in particular and indices have been...

17. Resultados preliminares de la investigación “Las emprendedoras y los emprendedores en Ciencia y Tecnología en Costa Rica un contraste de realidades de género” - Ferreto-Gutiérrez, Eugenia; Picado Arroyo, Rytha
The project is an investigation that seeks to demons­trate the contrasts of gender entrepreneurship on companies focused in Science and Technology in Costa Rica. By consulting secondary sources and experts on the topic, and deepen the field of Science and Technology. We have found a lack of documented information to take appropriate actions to guide the various actors involved at the level of Government, private sector and academia. In 2010, the Ministry of Economy, Industry and Commerce (MEIC) launches two public policy of promoting SMEs and other enterprises to which state the issue of gender as a crosscutting issue. In...

18. Impacto que genera un proyecto sobre oratoria en estudiantes de primaria de zonas rurales de Cartago - Amador Solano, María Gabriela
This article aims at showing the development and relevance of an extension project in seven rural schools located in “circuito 05” in the central area of Cartago. The main goal is to enhance oral commu­nication in elementary school students. The project was designed as a training workshop for the teach­ers in the chosen schools in order to be taught to students by implementing an oratory club. In each student´s dissertation, the researchers observed the enthusiasm that the project caused in the schools. Objectives, contents, activities, assessment and observations were designed in a didactic plan to be used upon needs of...

19. Razonamiento estratégico que promueve el comportamiento persistente: un enfoque experimental - Torres Carballo, Federico; Sandoval Sánchez, Yarima
This research aims to apply experimental techniques used to study the strategic behavior in games of Hide and Seek, as a framework for representing business situations more realistic and elaborate. To promote strategic thinking and persistence, repeated matching games between strangers are applied, and one with fixed an allocation (down payment decreases each round) with the possibility of abandonment in any round and keeping the rest of the initial allocation. In fact, the strategic reasoning is the diversion of random choices along of repetition and dropout rates of gambling, loss aversion and cultural differences that seem to frame various strategic...

20. Condición actual del mercado del abono orgánico en el cantón de Alvarado, Cartago - Brenes Peralta, Laura; Jiménez Morales, María Fernanda
Market conditions, such as the supply, the demand and the prices, are vital to establish a marketing strategy in any kind of product, and compost should not escape this practice. The idea of creating this study was born due to the Municipalidad de Alvarado´s Solid Waste Management Program. This local government, located in Cartago, Costa Rica has achieved important progress in environmental education, residues classification and separation, and domestic organic residues recycling through composting practices. This last process was initiated by pilot trials, developed by Fabián Marín Rivas, an Agribusiness student from TEC in his Graduation Project. Since the obtained...

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