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UNED Research Journal / Cuadernos de Investigación UNED
Number of Followers: 0  

  This is an Open Access Journal Open Access journal
ISSN (Online) 1659-441X
Published by Universidad Estatal a Distancia Homepage  [6 journals]
  • Culturable bacteria resistant to oxytetracycline during the
           vermicomposting of bovine excreta

    • Authors: Lorena Uribe-Lorío, Rodolfo WingChing-Jones, Daniela Vidaurre-Barahona, Lidieth Uribe, Luis Felipe Aráuz
      Pages: e4586 - e4586
      Abstract: Introduction: Bacteria with resistance genes to the antibiotic oxytetracycline have been detected in dairy cow manure worldwide, however, it is common a practice to use this manure as fertilizer. Vermicomposting can reduce the problem, but this subject has not been evaluated in Costa Rica. Objective: To analyze the presence of bacteria resistant to oxytetracycline during vermicomposting in a Costa Rican dairy farm. Methods: We inoculated broths supplemented with oxytetracycline from fresh manure, precomposted manure, vermicompost and "compost teas" with and without molasses. We prepared “compost teas” with and without molasses from this sample. We extracted DNA from these liquid cultures and mass-sequenced the 16S ribosomal amplicon. Results: We classified 105 292 sequences in 58 amplicon sequence variants from broths supplemented with oxytetracycline, most of them identified as Proteobacteria, Bacteroidetes and Firmicutes. Fresh manure had the most resistant bacteria (32), followed by the “teas” without and with molasses. Precomposting and vermicomposting decreased the number and type of resistant bacteria. However, preparation of the teas caused the multiplication of bacterial genera recognized for their ability to accumulate resistance determinants. Conclusion: Precomposting and vermicomposting decreased the number and type of resistant bacteria.
      PubDate: 2023-05-31
      DOI: 10.22458/urj.v15i1.4586
      Issue No: Vol. 15, No. 1 (2023)
  • Reviewers list 2022

    • Authors: UNED Research Journal
      Pages: e4789 - e4789
      Abstract: Reviewers list 2022
      PubDate: 2023-05-30
      DOI: 10.22458/urj.v15i1.4789
      Issue No: Vol. 15, No. 1 (2023)
  • First pages 15(1)

    • Authors: UNED Research Journal
      Pages: e4788 - e4788
      Abstract: First pages 15(1) June 2023
      PubDate: 2023-05-30
      DOI: 10.22458/urj.v15i1.4788
      Issue No: Vol. 15, No. 1 (2023)
  • Museum specimens and occurrences of Glottidia audebarti, Discradisca

    • Authors: José A. Vargas Zamora, Rita Vargas-Castillo
      Pages: e4624 - e4624
      Abstract: Introduction: Lamp shells or brachiopods have a rich fossil record but only about 400 extant species. Their diversity on the Eastern Pacific is poorly known and only eight species are reported for the Pacific of Costa Rica. Objective: To list the specimens from Costa Rica and provide a distribution map along its Pacific coast. Methods: We checked collections at the University of Costa Rica (MZ-UCR) and Scripps Institution of Oceanography. Results: We found 22 records at MZ-UCR and 10 at Scripps, both include unidentified specimens, as well as Glottidia audebarti and Discradisca strigata, which are frequently collected intertidally. Conclusion: The study of Eastern Pacific living brachiopods is at an early stage; ecological studies could focus on the more easily accessed intertidal species.
      PubDate: 2023-05-30
      DOI: 10.22458/urj.v15i1.4624
      Issue No: Vol. 15, No. 1 (2023)
  • Rapid assessment of non-flying mammals in three levels of human
           disturbance, Hacienda Barú National Wildlife Refuge, Costa Rica

    • Authors: Diego Fallas-Madrigal, Catherine Sanchez-González, Didier González-Mora, Melissa Chavarría-Arroyo, Mercedes Penit-Llobet
      Pages: e4558 - e4558
      Abstract: Introduction: Change of natural land use has become major a driver of biodiversity loss around the world. Mammals are important components of forests because they affect forest structure and composition, but few studies have compared mammals in tropical areas with different levels of human disturbance. Objective: To do a rapid assessment of non-flying mammals in Hacienda Barú National Wildlife Refuge, Costa Rica, in three zones with different levels of human disturbance. Methods: On July 18-21, 2019, we identified non-flying mammals with trail walk sightings, camera traps, and Sherman traps. Results: We identified 17 species but no differences among zones. The most common were Cebus imitador and Pecari tajacu, the most used plant was Mangifera indica. Conclusion: This brief study identified 17 non-flying mammals in this reserve.
      PubDate: 2023-05-30
      DOI: 10.22458/urj.v15i1.4558
      Issue No: Vol. 15, No. 1 (2023)
  • Ichthyofauna diversity and water quality in rivers in the southern zone of
           Costa Rica where dikes and channels were built to contain floods

    • Authors: Juan Carlos Villegas-Arguedas
      Pages: e4584 - e4584
      Abstract: Introduction: Freshwater fish can be negatively affected by human disturbances like infrastructure, dikes or canals, and extensive agriculture, which affect forest cover and promote sedimentation. Objetive: To evaluate the spatio-temporal composition of freshwater fish and its relationship with some physical-chemical water variables in three tropical rivers. Methods: I worked in the Grande de Térraba y Esquinas basins, Costa Rica, in three control sites and three sites with dike and channel influence. I sampled twice a month at the end of the rainy season (October-December, 2010) and the beginning of the dry season (January-March, 2011). I measured water quality variables and determined the type of environment or substrate, speed and altitude. Results: I captured 742 fish (24 species, 12 families). The most representative were Astyanax aeneus (44%), Poeciliopsis retropinna (14%), Dormitator latifrons (8%), Priapichthys panamensis (7%), Cryptotheros sajica (6%) and Brachyrhaphis roseni (4%). There were no statistically significant differences among sites. Conclusion: The fluctuations of environmental variables, and the trends in fish abundance, richness, and distribution, did not differ among control sites and anthropologically affected sites.
      PubDate: 2023-04-27
      DOI: 10.22458/urj.v15i1.4584
      Issue No: Vol. 15, No. 1 (2023)
  • Optimization of the production process of artisan ice cream

    • Authors: Yasmin Zaldivar Montes de Oca, Jorge Luis Montero Bizet
      Pages: e4603 - e4603
      Abstract: Introduction: The growing demand in the food market creates the need to produce foods of world preferences. Artisanal ice cream, today, is a product of great acceptance and mass consumption. Objective: Analyze the different factors that influence the optimization of the production process of artisan ice cream. Methods: We manufactured 30L of ice cream to know the relevance and influence of the operation and quality standards, in addition to the variables of quality involved in the production process. Results: The component with the greatest influence on the cost structure is the raw material (47,87%), so it is necessary to consider the area and the equipment where it is transformed, the order of addition and compliance with the essential regulations that govern the process. process to achieve a final product with the required quality and at the lowest possible cost by making maximum use of the raw material. Conclusion: Compliance with the operating standards of the equipment and correct weighing of the raw material are two factors that ensure the quality of artisanal ice cream.
      PubDate: 2023-04-27
      DOI: 10.22458/urj.v15i1.4603
      Issue No: Vol. 15, No. 1 (2023)
  • Effect of two drainage rates on cucumber (Cucumis sativus) under
           greenhouse conditions

    • Authors: José Eladio Monge-Pérez, Julio César Loáiciga-Arias, Werner Salazar-Salazar, Michelle Loría-Coto
      Pages: e4459 - e4459
      Abstract: “Effect of two drainage rates on cucumber (Cucumis sativus) under greenhouse conditions”. Introduction: Drainage rate is an important factor in hydroponic production. Objective: to evaluate the effect of two drainage rates on the yield and quality of cucumber (cv. Modan) under greenhouse conditions in the dry and rainy seasons. Methods: We used fertigation and coconut fiber as substrate. Results: In all quality categories, there were no statistically significant differences between irrigation rates for the number of fruits per m2, fruit weight and yield; while the percentage of total soluble solids was higher at 10% irrigation. The rainy season cucumbers had more total fruits per m2; commercial fruit weight; and total, second and third quality yield. Conclusion: For this conditions, a 10% irrigation rate will save water and nutrients, and increase crop profitability.
      PubDate: 2023-04-15
      DOI: 10.22458/urj.v15i1.4459
      Issue No: Vol. 15, No. 1 (2023)
  • Human-wildlife conflict in a buffer zone in San Ramón, Costa Rica

    • Authors: Rebeca Solano-Gómez, José Manuel Mora
      Pages: e4462 - e4462
      Abstract: “Human-wildlife conflict in a buffer zone in San Ramón, Costa Rica”. Introduction: Currently, biodiversity is mainly managed by protected areas, but proximity with human activities results in conflicts, which are poorly studied in the tropics. Objective: To estimate human-wildlife conflict in the buffer zone of the Alberto Manuel Brenes Biological Reserve, San Ramón, Costa Rica. Methods: We interviewed the owners or managers of 59 farms. Results: We recorded 540 incidents, mostly with mammals (N=479); coyotes (Canis latrans) killed 1 074 animals in 183 attacks at 12 farms. We also recorded conflicts with jaguar, Panthera onca, puma, Puma concolor, ocelot, Leopardus pardalis, and margay, Leopardus wiedii, which preyed on 261 domestic animals. Other mammals and snakes were also reported, especially the Fer-de-lance, Bothrops asper. In six occasions, the incidents took place over 500m from a house; however, most were 0-25m from a house (mean 398m). The farmers have sacrificed pumas, coyotes, raccoons and snakes and there was not a coordinated control effort from institutions, NGOs and communities. Conclusion: Coyotes are the most common wild animals involved and there is need for a coordinated effort that includes both organizations and communities.
      PubDate: 2023-04-15
      DOI: 10.22458/urj.v15i1.4462
      Issue No: Vol. 15, No. 1 (2023)
  • Spatial and temporal composition of aquatic birds and raptors in wetlands
           of central Mexico

    • Authors: Héctor Cayetano-Rosas, Montserrat Ramírez Hernández, J. Oswaldo Gómez-Garduño, Neptalí Piñón Santoyo, Rogelio Bautista-Trejo, Juan Gerardo Valverde Nieto, Jorge Ramírez-Albores
      Pages: e4382 - e4382
      Abstract: Introduction: Wetlands play an important role as habitats for various groups of birds, particularly those with aquatic habits. Despite their high biodiversity, in Mexico there are few studies on the composition and dynamics of bird assemblages in these wetlands. Objective: To evaluate the spatial and temporal dynamics of the aquatic bird and raptor community in wetlands. Methods: To characterize waterfowl and raptors, transects of variable distance were checked monthly from November 2019 to February 2022 in wetlands located in the Metropolitan Zone of Mexico City. Results: We counted 105 bird species. The highest values of diversity were in Laguna de Zumpango (91 species) and Lake Nabor Carrillo (91). Most of these species are migratory (63%), while 30% are residents, and 7% are introduced. Significant spatial and temporal differences (p<0,05) were found in the composition of the bird community. Conclusion: The highest diversity was in Zumpango and Nabor, and most species are migratory.
      PubDate: 2023-03-31
      DOI: 10.22458/urj.v15i1.4382
      Issue No: Vol. 15, No. 1 (2023)
  • In vitro life table of the storage mite Tyrophagus putrescentiae (Acari:

    • Authors: Pamela Murillo, Hugo Aguilar
      Pages: e4335 - e4335
      Abstract: Introduction: The mite Tyrophagus putrescentiae is a common contaminant of stored products and an important pest in plant tissue culture laboratories, because they diseminate fungi and bacteria. Objective: To describe the reproduction and life table of T. putrescentiae in vitro. Methods: We reared the mites with its associated fungus Leptosphaerulina sp., recording growth and development every 12h. Results: The duration of the egg, larva, protonymph, and tritonymph stages of cohort 1 was 4,52; 1,57; 1,37 and 1,29 days (cohort 2: 4,54; 1,44; 1,31 and 1,45 days, respectively). Cohort 1 periods of pre-oviposition, oviposition and post-oviposition were 1,86; 7,21 and 1,35 days (most cohort 2 individuals did not reach maturity). The intrinsic rate of natural increase (rm) was 0,11 individuals per female per day, the net reproduction rate (Ro) was 29,21; the generation time was 29,47 days, and the finite rate of increase (λ) was 1,12 times per female per day. Conclusion: Under the typical laboratory conditions, T. putrescentiae can multiply its initial population in a single day, which explains the population explosions observed in these laboratories.
      PubDate: 2023-03-27
      DOI: 10.22458/urj.v15i1.4335
      Issue No: Vol. 15, No. 1 (2023)
  • Conservation status, sex and body size of reptiles in Santiago Nonualco,
           El Salvador

    • Authors: José Nicolás Pérez-García
      Pages: e4403 - e4403
      Abstract: ABSTRACT. “Conservation status, sex and body size of reptiles in Santiago Nonualco, El Salvador”. Introduction: In recent years, there has been an increase in the number of reptile species considered threatened by emerging pressures in El Salvador. Body characteristics are observable traits that help in the evaluation of their conservation status, but little has been done in El Salvador on this subject. Objective: To evaluate the conservation status, sex and body size of the reptiles of Santiago Nonualco, El Salvador. Methods: We compared the conservation status in official listings with the Environmental Vulnerability Index. Results: We identified 36 species, 14 in some conservation category, six threatened and one at risk of extinction in El Salvador. Individuals of medium body size and adults were the most abundant. Males were larger and more abundant, except in turtles. Conclusion: Santiago Nonualco provides refuge for several reptiles, including threatened species. Turtles differ from other reptiles in sexual differences; and small individuals were less frequently seen in this census.
      PubDate: 2023-03-26
      DOI: 10.22458/urj.v15i1.4403
      Issue No: Vol. 15, No. 1 (2023)
  • Pollution of the Durazno River water, Costa Rica: beyond the Dutch water
           quality index

    • Authors: Douglas Alberto Venegas González, Eric Morales Mora, Kenia Barrantes Jiménez, Eddy Gómez Ramírez, Paola Fuentes-Schweizer, Andrea Irías Mata
      Pages: e4339 - e4339
      Abstract: ABSTRACT. “Pollution of the Durazno River water, Costa Rica: beyond the Dutch water quality index”. Introduction: The micro-basin of the Durazno River in Costa Rica is a source of water for human consumption, but is suspected of microbiological pollution from several land uses. Objective: To assess the water quality of the Durazno micro-basin from the physicochemical, microbiological and antibiotics points of view. Methods: We used the Dutch Water Quality index; Standard Methods for the Examination of Water and Wastewater; and solid-phase extraction and ultra-high performance liquid chromatography coupled to tandem mass spectrometry. Results: While physicochemical parameters indicated an adequate water quality, microbiologically this water is not acceptable for human consumption. The water has Doxycycline and Cefotaxime, possibly of agricultural origin. This is the first report of Cefotaxime in water from Costa Rica. The Dutch index fails to take into account microbiological parameters that are also important. Conclusion: The Durazno River does not meet the standards for human water consumption and the Dutch index needs to be complemented with microbiological parameters.
      PubDate: 2023-03-25
      DOI: 10.22458/urj.v15i1.4339
      Issue No: Vol. 15, No. 1 (2023)
  • Socio-agronomic classifiction of plantain-producing farms in the Caribbean
           region, Costa Rica

    • Authors: Vesalio Mora Calvo, Patricio Rojas Sanabria, Nancy Chaves Méndez
      Pages: e4337 - e4337
      Abstract: ABSTRACT. “Socio-agronomic classifiction of plantain-producing farms in the Caribbean region, Costa Rica.” Introduction: Plantain is a food for millions of people in developing countries, and in Costa Rica its production is mainly located in the Caribbean region, with 3 354 farms, with low productivity and little technological adoption. Despite being a crop present in 56% of the small farms in the Limon´s province, there are few studies on the conditions of the farms and the people who grow plantain. Objective: To prepare a typology of plantain farms in the Caribbean region of Costa Rica according to productivity. Methods: 342 surveys were applied to farmers in six counties, corresponding to 28% of the plantain farms affected by the flooding of 2015. Results: Three types of farms were found, type 1 are the most efficient due the use of supplies and profitability, they represented 10% of the total farms and had the highest annual yields 49MT/ha). These farms have 0,8 ha of plantain crops, with densities greater than 2 000plants/ha, use corms of 500 to 800g, apply ammonium sulfate, shore-up the plants, bag the bunches, renew the plantations every 1 to 2 years and the people who attend these plantations are under 50 years of age. On the other hand, 66% of farms are type 3, producing 18MT/ha/year. Conclusion: The farms of the six counties have significant differences, especially in cultivated area and productivity, with farms smaller than 1ha being the most efficient and most profitable, and those of Alta Talamanca being the most biodiverse with 79% managed under agroforestry systems. Finally, plantain is a vulnerable production system, mainly due to agronomic management, the few phytosanitary controls and the weak training received by farmers.
      PubDate: 2023-02-28
      DOI: 10.22458/urj.v15i1.4337
      Issue No: Vol. 15, No. 1 (2023)
  • Floristic composition of the natural regeneration of very wet premontane
           forest in Poás, Costa Rica

    • Authors: Isler F. Chinchilla, Nathalie Goebel-Otárola
      Pages: e4412 - e4412
      Abstract: ABSTRACT. “Floristic composition of the natural regeneration of very wet premontane forest in Poás, Costa Rica”. Introduction: Natural restoration is a low cost and nature-based way to restore part of habitats degraded by deforestation. Objective: To document the floristic composition of a regenerating vegetation fragment of very wet premontane forest. Methods: We did a floristic inventory in 5,59ha through exhaustive walks. Results: We documented 74 families, 144 genera and 170 native species, and 15 families, 21 genera and 22 exotic species, and one hybrid. The families with the highest genera and species riches were Asteraceae, Fabaceae, Solanaceae, Rubiaceae, Euphorbiaceae, Polypodiaceae, Lauraceae, and Pteridaceae. The genera with the highest species richness were Solanum, Pleopeltis, Pteris, Croton, and Piper. We identified two endemic species, Costus montanus and Sechium tacaco. 95% of the species are terrestrial, 4% facultative epiphytes, and 1% holoepiphytes; 30% trees, 29% shrubs, 27% herbs, 9% lianas, and 5% dwarf shrub. About 64% are strictly heliophytes, and 36% of the species may tolerate shade. 148 species have at least one vernacular name. Conclusion: It is relevant to conserve this forest fragment, which is in an early state of regeneration, because its species composition typical of the premontane forests of the Costa Rican Central Valley.
      PubDate: 2023-02-28
      DOI: 10.22458/urj.v15i1.4412
      Issue No: Vol. 15, No. 1 (2023)
  • Sexual differences in physical exercise: frequency, duration and type of

    • Authors: Lourdes Arce Espinoza, Karla Rojas Sáurez
      Pages: e4444 - e4444
      Abstract: ABSTRACT: "Sexual differences in physical exercise: frequency, duration and type of exercise". Introduction: Physical exercise is any activity programmed and carried out on a regular basis. It is considered a determining factor of prevention. Usually, reported exercise levels do not match trends in cardiovascular diseases and other pathologies associated with sedentary lifestyle. Objective: To test the hypothesis that there are differences between men and women in frequency, duration and type of exercise. Methods: We applied an online survey was applied to the staff of a Costa Rican university (N=3 998 persons) from October 1, 2021 to March 1, 2022 (45% filled it out). Results: Men exercise more than women, but women exercise longer. Men prefer strength exercises such as weight lifting, while women focus on flexibility, rhythm and coordination. Additionally, people with higher education and job positions exercise more. Conclusion: Sex, education and job position correlated with exercise type and frequency.
      PubDate: 2023-02-27
      DOI: 10.22458/urj.v15i1.4444
      Issue No: Vol. 15, No. 1 (2023)
  • Effect of trap size when quantifying plant material fall

    • Authors: Sergio Gabriel Quesada-Acuña, Gabriela Pérez-Gómez
      Pages: e4368 - e4368
      Abstract: Introduction: Many natural phenomena studied by ecologists (e.g. seed rain, litter production) require quantitative methods that collect data in the absence of the researcher, favoring for example traps. Traps vary in shape, size, and material, and their selection should be carefully considered. There are few studies that compare the performance of traps of different sizes and their effect on estimates. Objective: To compare two sizes of a common trap designed to quantify the fall of plant material. Methods: In a tropical urban park in San José, Costa Rica, we placed a total of 74 square traps (large trap = 0,50m2, with a concentric 0,25m2 subsection representing the small trap) in three microhabitats (grass; forest edge and under isolated trees). From July 2021 to June 2022 we collected the tramp contents twice a month (annual sampling effort: 144 hours per trap). Results: The large trap results in lower density estimates, leading to higher errors and standard deviations. The small trap estimates higher densities but reduces the standard deviation and error. The coefficients of variation of both traps were similar. Conclusion: Vegetation trap studies must consider the effect of trap size on density estimates, error estimates and standard deviations.
      PubDate: 2023-02-03
      DOI: 10.22458/urj.v15i1.4368
      Issue No: Vol. 15, No. 1 (2023)
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