Cuadernos Investigación - Academia.edu (original) (raw)

Papers by Cuadernos Investigación

Use of bacteria (Azospirrillum spp.) as biofertilizer for African star grass (Cynodon nlemfuensis... more Use of bacteria (Azospirrillum spp.) as biofertilizer for African star grass (Cynodon nlemfuensis). African star grass is important in some tropical regions and can benefit from the use of bio-fertilizers like Azospirillum. We tested three strains of Azospirillum as biofertilizer in Turrialba, Costa Rica, from 2011 through 2013. A single dose of 5 liters per hectare was used for the three strains (10 8 CFC.ml-1) and a three-way mixture of the strains; and compared with a dose of 10 tons of vermicompost and chemical fertilization (78 kg N per hectare). A second experiment evaluated Azospirillum for its potential to substitute chemical fertilizer in proportions of 0, 25, 50 and 75%. A dose of 5 L/ha (10 8 CFU.ml-1) was used for all treatments and compared to the dose of 100% of chemical fertilizer. Two of the strains and the three-way yielded similar forage biomass (3.65 to 3.93 t/ha) as the chemical fertilizer (4.12 t/ha). Fertilization with vermicompost was lower (3.56 t/ ha). A decline in rainfall from 2012 to 2013 reduced the grass biomass 25% when chemical fertilization was applied (4.07 vs 3.08 t/ha). In the second experiment, no significant differences were found in biomass yields for all treatments with Azospirillum or chemical fertilizer (2.97 vs 3.08 t/ha). Azospirillum has potential to maintain the productivity of African star grass under a grazing system, but further research is required to define the number of applications per year to maintain a constant effect.

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The African giant pouched rat (Cricetomys gambianus) and greater cane rat or African cane rat (Th... more The African giant pouched rat (Cricetomys gambianus) and greater cane rat or African cane rat (Thryonomys swinderianus) both have similar body conformation and share similar ecological biome. This study aimed to compare mandibular parameters in adults of both species. For this purpose, 9 lateral mandibular landmarks in male T. swinderianus (n=11) and C. gambianus (n=12) were analyzed by geometric morphometrics. T. swinderianus presented a coronoid process equivalent to condyle and a more caudally displaced angular process, whereas cheek teeth was less prominent and shorter in C. gambianus. This study may be useful in solving phylogenetic ambiguities, wildlife surveillance and age-population control, ration formulation in captive species, and eco-migration. This is the first time to our knowledge that geometric morphometric comparison of mandibles in these African rodents has enabled an inference of ecological preferences in diet based on mandible shape. RESUMEN: Comparación de la morfología geométrica de la man-díbula de dos roedores africanos, Thryonomys swinderianus y Cricetomys gambianus (Rodentia: Thryonomyidae y Nesomyidae). La rata gigante africana (Cricetomys gambianus) y la rata de caña afri-cana (Thryonomys swinderianus) tienen conformación corporal similar y biomas similares. Este estudio tuvo como objetivo comparar los pa-rámetros mandibulares en adultos de ambas especies. Para ello usa-mos 9 puntos de referencia mandibulares laterales en machos de T. swinderianus (n = 11) y C. gambianus (n = 12) analizándolos mediante morfometría geométrica. T. swinderianus presentó un coronoides equi-valente al cóndilo y un proceso angular desplazado más caudal, mien-tras que los dientes de mejilla son menos prominentes y más cortos en C. gambianus. Este estudio puede ser útil para resolver ambigüedades filogenéticas, vigilancia de fauna y control con la edad de la población, formulación de raciones de especies en cautiverio, y eco-migración. Creemos que esta es la primera vez en que la comparación mandibu-lar de estos roedores permite inferir preferencias ecológicas en la dieta con base en la forma de la mandíbula.

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Assessment of ordinary solid waste generation in the canton of Belén in the period 2005-2015. Mun... more Assessment of ordinary solid waste generation in the canton of Belén in the period 2005-2015. Municipal solid waste management is a serious problem in most developing countries and local governments must have reliable information to make decisions. I ana-lized total waste, recoverable waste and organic waste generation in Belén, Heredia, Costa Rica from 2005 through 2015. I found significant differences between the periods 2005-2010 and 2010-2015 (p<.0001), associated with population growth. More waste collection alternatives seem to bring more generated waste (p<.0001). The generation of CH 4 in the study period was 52 759.85 Mg of CO 2 e. The local government should focus on managing organic waste and promote alternative collection methods for recoverable. The evaluation of reliable information and extensive time scales is critical for successful management of solid waste.

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Orchid conservation in a private preserve at Palmares, Costa Rica. Madre Verde Private Preserve, ... more Orchid conservation in a private preserve at Palmares, Costa Rica. Madre Verde Private Preserve, located in Palmares (Alajuela, Costa Rica) protects a forest relict surrounded by pastures, bushes and abandoned agriculture grounds. An inventory was conducted in this preserve to determine the orchid species diversity, prepare orchid illustration materials, analyze geographic distribution and factors affecting identified species conservation, and collect spirit and dry herbarium specimens. High quality photos from all 109 observed orchid species in 46 genera were prepared. Genera with greater species numbers are Epidendrum and Maxillaria s.l. (both with 12 spp.). Most species (86%) are epiphytic and eight species are endemic to Costa Rica. Months with most species flowering were February, April, May, August and November during the study year 2011-2012. Geographical and altitudi-nal ranges from two data bases (CRBIO and IABIN) and the Costa Rica's Plant Manual were compared to the results of the present study, so we could broaden knowledge on these data for several species: 14 species were found in the preserve at higher elevations than in previous locations. Moreover, other five species were found at lower elevations than herbarium and data base records. Nine of the species observed were previously not collected in the whole Alajuela province. The most striking result was the finding of both Lepanthes guardiana and L. minu-tissima, which where illustrated and collected before this study only ca. 1867, there were no ecological or precised collection data, the only illustration of the former and specimens of the latter were in Vienna Herbarium (W) and no one could heretofore find them again in Costa Rica or elsewhere. We demonstrate that even small private preserves in very disturbed areas can protect small and rare orchids and many other plant species. We recommend continuing investigation on local floras and trying to reproduce endangered species from critical landscapes, in order to avoid local or total extinction. Instruction for preserve visitors and surrounding humans populations are under the activities that can guarantee species survival in the study area.

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Rediscovery of Tayassu pecari (Artiodactyla: Tayassuidae) in the Refugio Nacional de Vida Silvest... more Rediscovery of Tayassu pecari (Artiodactyla: Tayassuidae) in the Refugio Nacional de Vida Silvestre Mixto Caño Negro, Costa Rica. The white lipped peccary (Tayassu pecari) is a widely distributed Neotropical species that can be found from northern Argentina to southern Mexico. According to the IUCN, the white lipped peccary is vulnerable throughout its distribution range. In Costa Rica their distribution has decreased in 89%, its populations are in danger of extinction and are restricted to a few protected areas. This document presents the details of the first records of the presence of white lipped peccary in the Mixed National Wildlife Refuge of Caño Negro, where it was previously considered to be locally extinct. During 2013, 52 in depth interviews were conducted in several communities near the refuge. Between September and December 2015, eight camera traps were placed in farms close or within the refuge. In ten of the conducted interviews, people confirmed that there is a small population of these animals. Most people believe they live in a high and secluded sector of the refuge known as " Terrón ". Of the eight camera traps that were used, two were placed in this sector. One of these cameras registered a pack of white lipped peccary composed of at least eight individuals including adults and juveniles. Local ecological knowledge serves as a complement for technical knowledge and as a guide for planning and focusing efforts during the development of ecological research, such is the case of the present study. The confirmation of the presence of white lipped peccary is a finding of great importance since it can serve to increase the conservation measures that are applied in the refuge.

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Effect of Geophila macropoda (Rubiaceae) as " weed cover " on hydric erosion in banana plantation... more Effect of Geophila macropoda (Rubiaceae) as " weed cover " on hydric erosion in banana plantations, Guápiles , Limón , Costa Rica. The establishment of banana companies in Costa Rica brought employment and infrastructure improvements, but also social problems, destruction of forests, soil erosion and pollution of rivers and streams. Erosion in banana plantations may be diminished with plant cover. Here we analyze the effect of the plant Geophila macropoda on erosion caused by water in Guápiles, Costa Rica. We chose three soil classes I, II and III with and without G. macropoda. Between June and August 2012 periodic measurements were performed once a week, covering periods of low, medium and high rainfall. We found that erosion increases with precipitation and that cover with this plant reduces erosion in all soil types.

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The occurrence of Lagocephalus inermis (Temminck & Schlegel, 1850) is reported for the first time... more The occurrence of Lagocephalus inermis (Temminck & Schlegel, 1850) is reported for the first time from Digha extending the range of the species to the east coast of India based on one specimen. This species was already reported from southeastern coast of India and western coast of India. The 196 mm standard length specimen from Digha Mohana is described in detail.

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There are few scientific studies about sexual tourism in Costa Rica. The most important study abo... more There are few scientific studies about sexual tourism in Costa Rica. The most important study about male tourists, done by Megan Rivers-Moore, presented a series of hypotheses. Here I analyze all forum posts in the InternationalSexGuide.info from 2002 through 2015, and compare them with Rivers-Moore's hypotheses, the Intimacy Prism categories of Milrod and Weitzer and with female sex tourists (as reported in the literature). The 4 409 reports show that men interact in peer dialogues in which they mostly advise each other about how to get a satisfactory visit to Costa Rica: a visit that includes paid sex but is not limited to it. While sex working women have little interaction among themselves, these men feel part of a group and exchange useful information. The desire for a Girl Friend Experience, though not predominant, is frequent and fits biological adaptations for mate interactions among humans. Male tourists mostly make short visits in which they try to meet a few women and then focus on those that make the best impression. A few evolve into complex relationships that include emotional commitment. Despite the financial disparity between men and women, traditional gender roles underlie the relationships of both male and female tourists, probably reflecting a complex combination biological and cultural factors.

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The effect of feedback on performance and motivation in students taking Research methods for Heal... more The effect of feedback on performance and motivation in students taking Research methods for Health Sciences at UNED, Costa Rica. Feedback is an important tool in the distance learning process , it helps students to be more critical and analytic. The goal of this study was to measure the effect that feedback has on performance and motivation. We evaluated four tasks in which students had feedback and applied a survey that measured students' satisfaction with feedback. A significant improvement was found only between the third and the fourth tasks, suggesting that students wait until the end to apply what they learned; other problems include: that feedback was not always positive, unclear instructions about bibliographical references and insufficient time. We recommend strategies that can improve feedback , such as verbal instead of written feedback, co-evaluation and making students reflect, instead of giving them the correct answer. RESUMEN: La retroalimentación es una herramienta muy importante en la enseñanza y aprendizaje de los estudiantes a distancia por cuan-to los hace ser más críticos y reflexivos y la estrategia utilizada para generar este conocimiento es la clave para el éxito del estudiante. El objetivo de esta investigación fue medir el efecto que tiene la retroa-limentación sobre el rendimiento y motivación de los estudiantes y se logró mediante una prueba t que evalúo el rendimiento en cuatro ta-reas a las cuales se les dio retroalimentación y una encuesta en donde se midió su grado de satisfacción con respecto a la retroalimentación. Se encontró que hubo una mejora significativa entre la tercera y cuarta tarea, no así entre las dos primeras, lo cual se puede atribuir tanto a que los estudiantes esperan al final para aplicar lo que se les enseña así como a una retroalimentación no siempre positiva, falta de claridad en las instrucciones sobre uso de APA y falta de tiempo entre tareas. Se recomienda utilizar diferentes estrategias para realizar una retroali-mentación más efectiva como el uso de la voz en vez de la forma escri-ta, la coevaluación y por último, la explicación de los temas haciendo reflexionar al discente sobre qué se puede mejorar, en vez de sólo dar la respuesta correcta.

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Velvet worms are ancient predators with Cambrian origins that occasionally prey on Ctenid spiders... more Velvet worms are ancient predators with Cambrian origins that occasionally prey on Ctenid spiders. Here we report the opposite case: wolf spiders (Ctenus spp.) feeding on Epiperipatus spp. in Colombia and Costa Rica. Apparently the worms could not expel their defensive adhesive, and the efficacy of the spider venom suggests that onychophoran nerves and muscles are biochemically equivalent to those of insects.

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Photographic evidence of undescribed species of velvet worms (Onychophora: Peripatidae) from Cost... more Photographic evidence of undescribed species of velvet worms (Onychophora: Peripatidae) from Costa Rica. Onychophorans are hard to find and identify to species under field conditions. Currently, there are seven species described from Costa Rica, and an appropriate taxonomic revision is necessary. However, technology allows the documentation of rare and even undescribed species. Here we compile donated photographs and online images to identify 18 new Costa Rican species (based on taxonomic characteristics or geographical distribution). In addition we present relevant scientific information for each. Although it is not possible to make a formal description of species from photographs, this compilation shows where they can be searched for future research. Our goal is to preserve this information and to raise awareness among biology students and nature photographers about the importance of finding an onychophoran. These findings frequently result in new species discoveries.

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