UNED Research Journal

Physicochemical characterization of Costa Rican pork shoulder

Alejandro Chacón Villalobos, Sianny Chavarría Zamora — Thu, 01 Aug 2024 00:00:00 -0600

Introduction: Pork meat offers high-quality nutrients, and in 2022, global pork production reached 125 million tons, with the highest demand in Asia. Considering some health implications of red meat, it is essential to characterize pork meat cuts, particularly in Costa Rica, where each person consumed a mean of 17kg in 2022. Objective: To physico-chemically characterize the pork shoulder cuts in Costa Rica. Materials and Methods: We collected samples of pork shoulder cuts, with an average weight of 2,5kg, selected randomly two days after slaughtering, and applied physico-chemical analyses Results: The samples had an average of crude protein of 20,7±1,6%, with a polyunsaturated fatty acids/saturated fatty acids (PUFA/SFA) ratio of 0,36 and low sodium content (0,056g/100g). The energy value of the pork shoulder cut reported in this research (139,6kcal/100g), classifies it as one of the lowest energy cuts of pork. Of total fat, 96.7%±0,2 was represented by six fatty acids: oleic, palmitic, stearic, linoleic, palmitoleic and myristic. The cutting force was 4,62kgf, and the color was characterized by a dark brown tone. Conclusion: Costa Rican pork shoulder stands out for its low energy value and high protein content, making it suitable for weight loss dietary plans.

Environmental impact and methane emission from the Naranjito garbage dump, Guayas – Ecuador

Freddy Gavilánez-Luna, César Morán Castro, Gabriela Campoverde Verdugo — Mon, 01 Jul 2024 00:00:00 -0600

Introduction: Outdoor garbage disposal and accumulation sites concentrate water, soil and atmospheric pollution; however, there is little information on this problem in Ecuador. Objective: Assess the environmental impact, including methane emissions, from the open-air garbage dump in Naranjito, Ecuador. Methods: To determine the methane emission rate from solid waste biomass, we applied the static camera method, with a portable device, for 15 continuous days (May-June 2023) and at 08:00, 12:30 and 16:00. For the qualitative evaluation of environmental impact, we used the Global Index weighting, based on the impacts generated in the physical and perceptual environment. Results: The global Index was 53,3, i.e. critical impact; mean emission rate was 858,8mg/m²/h, higher than the emission rate of the surrounding soil (133,4mg/m²/h; p<0,05). Conclusion: A sustainable management alternative is urgent to reduce the methane emission rate in Naranjito.

Characterization of lactic acid bacteria isolated from two samples of biole-type bio-inputs with the production capacity of indolic compounds

Mon, 01 Jul 2024 00:00:00 -0600

Introduction: Modern agriculture seeks to improve sustainability and reduce environmental impact, while meeting the nutritional needs of current and future generations. A promising strategy is the use of microbial biostimulants to increase crop yields and decrease dependence on agrochemicals and fertilizers. Among these biostimulants, those that use beneficial microorganisms such as plant growth-promoting bacteria stand out. We focused this study on isolating and identifying lactic acid bacteria present in artisanal bioles, and characterizing them by their ability to produce indolic compounds. The findings suggest that some lactic acid bacteria present in the two bioles samples can act as producers of indole compounds, such as 3-indoleacetic acid, which makes them a promising alternative for more sustainable and environmentally friendly agricultural practices. Objective: Isolate and identify lactic acid bacteria present in two samples of artisanal biole, and characterize them by their growth and their ability to produce indolic compounds. Methods: We use molecular techniques such as 16S rRNA gene analysis and multilocus typing sequencing analysis to identify strains of lactic acid bacteria present in artisanal biole. Subsequently, we characterized the isolated strains using growth kinetics and colorimetric tests for the detection of indolic compounds, and the quantification of said compounds using high-efficiency liquid chromatography (HPLC). Results: We identified three different genera of lactic acid bacteria species which were Lacticaseibacillus paracasei, Lactiplantibacillus sp., and Lacticaseibacillus pantheris. Lactiplantibacillus sp. stood out for their ability to produce 3-indoleacetic acid. (M2) and Lacticaseibacillus paracasei (M4) with a concentration of 16,75 µg/mL and 4,57 µg/mL, respectively. Conclusion: Our results suggest that some lactic acid bacteria present in artisanal bioles can act as producers of indolic compounds such as 3-indoleacetic acid, which makes them a promising alternative for more sustainable and environmentally friendly agricultural practices.

Antibacterial, antifungal, toxic and larvicidal activity of Ficus pumila (Moraceae) and Phthirusa stelis (Loranthaceae)

Tue, 16 Apr 2024 00:00:00 -0600

Introduction: Ficus pumila and Phtirusa stelis are emerging as a source of natural products. Objectives: Identify the families of chemical compounds present in the species to be studied. Determine the antibacterial and antifungal activity of the crude extracts of F. pumila and P. stelis. Assess the toxicity of the crude extracts of the species against Artemia sp. Determine effects on Aedes aegypti larvae and. Methods: We evaluated the bioactivity of ethanolic, and isopropyl extracts obtained from the fruits, leaves and stems of both species were evaluated for antibacterial activity, antifungal activity, toxic activity against Artemia sp, A. aegypti larvae and phytochemical study. Results: We identificated flavonoids, tannins, and polyphenols in isopropyl and ethanol extracts of leaves, stems and fruits of F. pumila. We detected flavonoids, tannins, anthraquinones, triterpenes, and polyphenols in isopropyl and ethanol extracts of stems and leaves of P. stelis. We detected flavonoids, tannins, anthraquinones, triterpenes, and polyphenols in isopropyl and ethanol extracts of stems and leaves of P. stelis. F. pumila, the isopropyl stem extract demonstrated the most effective activity, since it exerted antibacterial activity, with inhibition halos being observed on B. subtilis (10 mm) and E. coli (7 mm), while the ethanolic extract of the leaves showed effect on Staphylococcus aureus (11 mm). The ethanolic extract of P. stelis leaves exhibited activity against S. aureus (10 mm), B. subtilis (10 mm) and that of stem extract showed similar results with inhibition zone of halos of 11 and 10 mm, respectively. The isopropyl extract of leaves also displayed activity against E. coli (15 mm). None of the extracts from F. pumila and P. stelis, showed any growth inhibitory effect against the pathogenic fungi. The majority of P. stelis extracts showed positive LC results against Artemia sp., with the ethanolic leaf extract exhibiting high toxicity (0,01 µg/mL). The isopropyl leaf extract also showed high toxicity (0,01 µg/mL), as did the isopropyl stem extract (0,02 µg/mL). The ethanolic and isopropyl extracts of F. pumila and P. stelis did not show toxicity to Aedes aegypti larvae. Conclusion: The plant species F. pumila and P. stelis, can be considered as sources of important and promising compounds for therapeutic research. These plants have shown potential in various studies, and further research could lead to the discovery of new treatments and therapies.

Tacaco (Sechium tacaco; Cucurbitaceae): quantification of the variability in the number of spines and sutures of the fruit

José Eladio Monge-Pérez, Michelle Loría-Coto — Mon, 07 Oct 2024 00:00:00 -0600

Introduction: The fruits of tacaco, Sechium tacaco, a plant endemic to Costa Rica, are primarily consumed as a vegetable or dessert, and few studies have addressed the morphological variability of these fruits. Objective: To quantify the variability in the number of spines and longitudinal sutures of the fruit. Methods: We collected 6-90 fruits from each of 22 tacaco accessions, between 2013 and 2019. We evaluated longitudinal sutures and number of spines. Results: For 20 accessions, the mode was five complete longitudinal sutures. For incomplete longitudinal sutures, the modes were zero (8 accessions), one (6 accessions) and two (6 accessions). For total number of longitudinal sutures, 10 accessions had a mode of six and 10 accessions a mode of seven. For fruits with spines, six accessions had 15-19 spines per fruit, and four accessions 20-24 spines per fruit. Conclusion: The phenotypic variability in spines and longitudinal sutures, suggests that these characteristics are controlled by multiple genes, indicating a polygenic inheritance; this variability could be key for genetic improvement and conservation of the diversity of this species.

Chemical profile of essential oils of the Costa Rican native tree Myrcianthes storkii (Myrtaceae)

Carlos Chaverri, José F. Cicció — Thu, 25 Jan 2024 00:00:00 -0600

Introduction: The genus Myrcianthes ranges from southern Florida to Chile, including the Caribbean, and the species Myrcianthes storkii is a shrub or tree found in Costa Rica and western Panama, in wet to very rainy, cloud, and oak forests (altitude 1300-3150m). Objective: To identify the chemical composition of essential oils from leaves, floral buds, and twigs of M. storkii of Costa Rica. Methods: We obtained the essential oils through hydrodistillation in a Clevenger-type apparatus. The chemical composition of the oils was done by GC/FID and GC/MS, using the retention indices on DB-5 and Carbowax types of capillary columns in addition to mass spectra. Results: The oils consisted mainly of terpenoids (55,45-87,75%). A total of 281 compounds accounted for 91,27-74,56% of the total amount of oils. The major constituents from the leaf oil were myrcene (17,44%), cis-calamenene (12,60%), α-pinene (5,48%), (E)-caryophyllene (5,16%), limonene (3,91%), p-cymene (3,71%), 1,8-cineole (2,80%), and α-humulene (2,80%). The floral bud essential oil consisted mainly of α-pinene (15,23%), cis-calamenene (12,70%), myrcene (8,59%), 1,8-cineole (4,26%), germacrene B (3,65%), α-humulene (3,55%), and (E)-caryophyllene oxide (2,93%). The major components of twig oil were cis-calamenene (11,31%), palmitic acid (7,99%), (E)-caryophyllene (4,68%), -cadinene (3,28%), cubenol (3,24%), and (Z)-caryophyllene oxide (2,94%). Conclusion: The presence of a significant quantity of myrcene and cis-calamenene seems to be characteristic of this species.

Insights into the human-jaguar Panthera onca (Carnivora: Felidae) interactions in Tortuguero National Park, Costa Rica

Stephanny Arroyo-Arce, Ian Thomson — Thu, 08 Aug 2024 00:00:00 -0600

Introduction: Human-wildlife interactions are on the rise due to anthropogenic pressures. Understanding these interactions is crucial for preventing conflict and promoting coexistence, ultimately benefitting humans and wildlife. Objective: In this study, we analysed the interactions between humans and jaguars Panthera onca in Tortuguero National Park, Costa Rica. Methods: We examined data concerning jaguar sightings within Tortuguero National Park, Costa Rica compiled from 2000 to 2022. Results: A total of 381 jaguar sightings were recorded, of which 75% occurred in the coastal habitat; 81% occurred during the leatherback sea turtle Dermochelys coriacea (March-May) and the green sea turtle Chelonia mydas (June-October) nesting seasons. From photographic records, 26 individual jaguars were identified (14 females, 12 males). Furthermore, 9% of the sightings were reported within the boundaries of Tortuguero village, where at least 48 domestic dogs Canis lupus familiaris were attacked by jaguars. Conclusions: Despite the jaguar's cryptic nature, the data show an increase in the frequency and duration of jaguar sightings over the years. This trend is likely due to an increase in the local jaguar population and possibly an increase in jaguars' tolerance towards humans, possibly triggered by people's inappropriate behaviour (e.g. approaching jaguars while feeding, mating or with their cubs) during the sightings. Our study also highlights the potential for conflict due to jaguar predation of domestic dogs, which is increasing within the study area. Therefore, there is a need for management action to promote coexistence between humans and the local jaguar population in Tortuguero National Park, Costa Rica.

Basic morphometry of thorny fruits in tacaco (Sechium tacaco; Cucurbitaceae) accessions

José Eladio Monge-Pérez, Michelle Loría-Coto — Thu, 01 Aug 2024 00:00:00 -0600

Introduction: There are few studies on the morphology of tacaco (Sechium tacaco) fruits from different accessions. Objective: To do the morphological characterization of thorny fruits from tacaco accessions. Methods: Between July 2017 and September 2019, we measured 62 to 88 fruits with thorns from twelve tacaco accessions, at various sites in Costa Rica. Results: We found differences between accessions for all variables. The ranges of means between accessions were: weight (20,15-39,71g), length (45,92-61,33mm), width (33,26-42,77mm), thickness (25,85-30,86mm), number of complete longitudinal sutures (5,04-5,71), number of incomplete longitudinal sutures (0,75-2,27), total number of longitudinal sutures (5,84-7,52), number of thorns (3,18-24,30), length/width ratio (1,35-1,52), length/thickness ratio (1,77-2,08), and width/thickness ratio (1,25-1,44). Conclusion: There is an important variability in the morphological characteristics of these fruits. We document, for the first time, the existence of the “tacaquilla”, defined by small fruits.

Cytogenics, morphology and viability of Borreria spinosa (Rubiaceae) pollen grains

Thu, 01 Aug 2024 00:00:00 -0600

Introduction: Borreria spinosa is a herbaceous plant considered a weed in agricultural crops, although it also has potential in apiculture. Despite its agronomic importance, its cytogenetic and palynological traits are poorly known. Objective: To do the cytogenetic characterization of B. spinosa, describe the morphology of its pollen grains, and estimate their potential viability. Methods: We collected plant material in Santiago del Estero, Argentina, in May 2017 and used classical methods (8-hydroxyquinoline and Farmer for mitosis and meiosis; viability with Müntzing; pollen morphology with nonacetolysed and acetolysed techniques, and SEM). Results: B. spinosa has a chromosome number of 2n = 56, with a karyotype of 46 m + 10 sm. Meiotic abnormalities mainly include chromosomes outside the equatorial plate, lagging chromosomes, and cytomixis. Pollen grains are small to medium-sized, suboblate to oblate-spheroidal, with a viability of 70%. This is a tetraploid species, most chromosomes are metacentric or submetacentric; and it has irregular meiotic behavior and cytomixis, with concomitant low viability in pollen grains. Conclusion: In B. spinose, pollen grains have similar characteristics to other species of the genus Borreria.

Sprout emission and relationship with climate in pitahaya (Selenicereus costaricensis; Cactaceae)

José Eladio Monge-Pérez, Michelle Loría-Coto — Mon, 01 Jul 2024 00:00:00 -0600

Introduction: For the production of fruit crops, it is important to know the relationship between climatic variables and crop phenology. There are few studies on this topic in pitahaya cultivation in Costa Rica. Objective: to evaluate the type of relationship between climate and the emission of sprouts in the cultivation of pitahaya cv. San Ignacio. Methods: We carried out the research between 2017 and 2019. We evaluated the following variables: number of vegetative sprouts (NVS), number of reproductive sprouts (NRS), average temperature (Ta), minimum temperature (Tmin), maximum temperature (Tmax), relative humidity (RH), and rainfall (R). We calculated Spearman correlations between variables. Results: We did not find statistically significant correlations between NVS and the other analyzed variables. On the other hand, we observed a significant positive correlation between the NRS and minimum temperature (r=0.52**), rainfall (r=0.36*), and relative humidity (r=0.33*). These results indicate that as precipitation, relative humidity, and minimum temperature increase, the number of reproductive sprouts also increases. We additionally identified correlations between NVS, NRS, and climatic variables during the months prior to sprouting. Conclusion: No defined pattern was observed in the emission of vegetative sprouts, while the emission of reproductive sprouts occurred mainly during the initial and middle phases of the rainy season. Furthermore, it was observed that generally, during the emission of reproductive sprouts, few or no vegetative sprouts were produced.

Sludge biological index as operational bioindicator of two hospital wastewater treatments in Costa Rica

Margarita Loría Naranjo, Wilson Beita Sandí — Mon, 30 Sep 2024 00:00:00 -0600

Introduction: Biological monitoring in activated sludge wastewater treatment systems provides comprehensive results and serves as a complementary tool in operational control decisions. One such tool is the Sludge Biological Index (SBI), which is based on protozoa. However, there is limited data on this topic in Costa Rica. Objective: To evaluate the SBI as a bioindication tool in hospital wastewater. Methods: From February to April 2022, we collected a total of 36 samples from a Conventional Activated Sludge Treatment system and a Membrane Bioreactor (MBR) at a Costa Rican hospital. Results: The removal efficiency of BOD and COD was higher in the MBR; however, in both cases, the efficiency was high (greater than 85%), and this is related to the high SBI values. Nitrogen removal efficiency did not exceed 50% (MBR). No environmental parameter correlated with SBI values, but sludge age affected the SBI value. Conclusion: In both the conventional treatment system and the MBR, the average SBI values indicate good performance and high-quality activated sludge

Electroactive microorganisms in coffee processing wastewater (iron redox processes)

Joice Castro Alvarez, Lidieth Uribe Lorío , Paola Fuentes-Schweizer — Thu, 21 Dec 2023 00:00:00 -0600

Introduction: Wastewater is often a good source for electrogenic bacteria, which are essential for Microbial Fuel Cells (MFCs). The electrons they release while metabolizing organic matter is evidence of their electrogenic capacity. Objective: To evaluate the iron-reducing capacity of bacteria isolated from coffee wastewater. Methods: We isolated morphologically distinct facultative bacteria from the anode electrode of MFCs, with coffee mill wastewater as our substrate. We did a preliminary identification with the Biolog GEN III system (Biolog Inc. Hayward, CA, USA). To assess the conversion of iron (III) to iron (II) by the isolated bacteria, we tested iron (III) citrate, iron (III) chloride, and iron (III) oxide. For comparison, we used S. oneidensis as a positive control in our experiments. Results: We identified eight bacterial isolates with a predominance of non-sporulated Gram positive bacilli morphology. They have reductive activity of iron compounds, giving the best conversion percentages from a for iron oxide (III). The isolate coinciding with the genus Citrobacter (SB), the only Gram negative bacillus, obtained iron conversion percentages higher than 1,0% in the three iron compounds (maximum: 4,3%). Conclusion: In the residual water from the coffee process, there are bacteria with electrogenic capability that could be used in Microbial Fuel Cells.

Effect of an enzymatic treatment on the viscosity, betacyanin content and color of a pitahaya pulp (Hylocereus polyrhizus)

Thu, 08 Aug 2024 00:00:00 -0600

Introduction: Pitahaya is a fruit with an attractive composition for consumers whose pulp has great potential for the development of functional and innovative food products. One of the main challenges is to produce a stable pulp with a viscosity that facilitates its handling during processing. Objective: To evaluate enzymatic maceration conditions that allow improving the rheological properties of pitahaya pulp by reducing its viscosity, with the least possible effect on betacyanins and color. Methods We evaluated the conditions of the enzymatic treatment by measuring the change in the viscosity of the pitahaya pulp, the concentration of betacyanins and the instrumental color using a rotating composite central design, considering two factors: enzyme concentration and maceration time. For the design points, the enzyme concentration was between 109,8g/ton and 640,2g/ton and the time between 1,0h and 3,5h; For the axial points, the minimum level of enzyme concentration was 0g/ton and the maximum was 750g/ton and with respect to time, the minimum was 0,5h and the maximum was 4,0h, being the central point of 375g/ton of enzyme and 2,3h maceration time. Results: The enzyme treatment evaluated allows a significant reduction in pulp viscosity with a low impact on betacyanins (92% average retention), while changes in instrumental color parameters that are not considered negative. Conclusion: The enzymatic treatment allows the viscosity reduction of the pitahaya pulp with little impact on compounds and characteristics of importance in this product. This has potential industrial application for handling and stabilization of a pulp that can be used for the development of various food products, allowing the valorization and use of the fruit.

Zoonotic and non-zoonotic gastrointestinal parasites in frogs from an urban tropical river of Costa Rica

Gabriela Pérez-Gómez, Ana Eugenia Jiménez-Rocha — Thu, 21 Dec 2023 00:00:00 -0600

Introduction: The urban ecosystems of Costa Rica are home to several anuran species that coexist with still poorly studied parasites. Objective: To report the presence of zoonotic and non-zoonotic gastrointestinal parasites in Hyalinobatrachium fleischmanni, Espadarana prosoblepon, Smilisca sordida, in urban river habtat in San José, Costa Rica. Methods: We analyzed 30 fecal samples, from specimens kept in the laboratory for ten months, with three diagnostic techniques. Results: We detected for the first time in Costa Rica the presence of Giardia duodenalis and Cryptosporidium parvum in H. fleischmanni, E. prosoblepon and S. sordida (with antigen detection tests); in addition, nematodes (Strongylidae and Rhabdias spp.), intestinal ciliates and cestode eggs with other diagnostic techniques. Conclusion: These urban frogs carried at least six types of parasites, some of them, first reports.

Implementation of a high dose routine dosimetry in a self-shielded irradiator

Walter Vargas-Segura, Laura Rojas-Rojas — Mon, 01 Jul 2024 00:00:00 -0600

Introduction: Ionizing radiation is applied in various fields, and dosimetric control guarantees the quality and safety of products during the irradiation process. There is a need for dosimetric calibration procedures in industrial irradiation plants, specifically for self-shielded irradiation systems. Objective: To implement high dose dosimetry in the routine control of irradiated materials within a self-shielded irradiator. Methods: We worked with 32 dosimeters; we divided the dose range used into 8 points and used four RED Perspex dosimeters per point. We measured the specific absorbance for each dosimeter; plotted these values against dose and produced a third-degree polynomial fit as a calibration curve. Results: We obtained the calibration curve with an r² of 0,9997. The uncertainties due to the dispersion of the dosimeters and the calibration curve were 1,39% and 0,22%, respectively, for a total uncertainty of 4,80%. This uncertainty includes dose determination with a factor coverage (k) equal to 2 for a 95% confidence interval. Conclusion: Perspex RED dosimeters can be used for routine control of irradiated products in a self-shielded irradiator system.

The role of wild mammals in seed dispersal and food chain in Costa Rican coffee agroecosystems

Ronald Sánchez-Brenes, Javier Monge-Meza — Wed, 10 Apr 2024 00:00:00 -0600

Introduction: Shade coffee farms are complex ecosystems and there is a need for better understanding of their function and environmental services. Some of their environmental functions are similar to forest ecosystems and biodiversity is important. Mammals play a crucial role in these agroecosystems, controlling vegetation abundance and composition, contributing to seed dispersal, nutrient recycling and soil maintenance through excavation and aeration. Objective: To identify the role of wild mammals in seed dispersal and food chain in Costa Rican coffee agroecosystems. Methods: We worked in Rincón de Mora, San Ramón, Costa Rica, from March 2019 to January 2022. We used Pixestt and Havahart traps, and camera traps, to examine feces and behavior; depending on species, sample size ranged between 2 and 87. Results: We identified 19 species of mammals. Heteromys salvini had coffee beans in its pockets. Echinosciurus variegatoides, Didelphis marsupialis and Philander melanurus fed on the local vegetation. Dasyprocta punctata had the most diet data; we found a beetle in the feces of Procyon lotor and observed Eira barbara chasing D. punctata. Conclusion: Coffee agroecosystems provide food for wild mammals, which in turn contribute to the coffee ecosystem as seed dispersers and population control.

Crustaceans in Phragmatopoma sp. (Polychaeta: Sabellariidae) intertidal reefs, Pacific, Costa Rica

José A. Vargas, Rita Vargas-Castillo, Jeffrey A. Sibaja-Cordero — Thu, 25 Jan 2024 00:00:00 -0600

Introduction: Annelid polychaete worms of the family Sabellariidae build reefs by cementing together sand grains. These reefs increase local habitat heterogeneity and species diversity. The reefs are used as a refuge by invertebrates, and crustaceans are frequent. Objective: To list the species of crustaceans found in Phragmatopoma sp. reefs on two localities of the North Pacific coast of Costa Rica and at the port of Puntarenas, Gulf of Nicoya estuary. Methods: We dislodged fragments of reef colonies qualitatively at low tide with a chisel, stored them in plastic bags and later disaggregated the fragments by hand. We identified the crustaceans whenever possible and deposited them in the collection at the University of Costa Rica (MZUCR). Results: We identified 30 species: 26 species of macro-crustaceans in samples from the North coast, eight of them Petrolisthes (Porcellanidae). From the Puntarenas samples we identified five species (27 macro-crustaceans and 3 isopods). A few micro-crustaceans (Amphipoda, Isopoda) were also present but not identified. Conclusions: The number of crustacean species found in Phragmatopoma sp. reefs is relatively high but comparisons with other studies are difficult. Porcellanid crabs are common on these reefs. The low diversity of Puntarenas reefs remains unexplained.

Distance to vegetation, road layout, and run overs of wild vertebrates in Puntarenas, Costa Rica

Thu, 01 Aug 2024 00:00:00 -0600

Introduction: Understanding the impact of roads on wildlife is crucial for implementing protective measures; Costa Rica is among the most studied tropical countries on this regard, but some areas remain poorly known. Objective: To evaluate the relationship between roadkill frequency, road layout and distance to vegetation. Methods: We worked over 15km from April 8 to 10, 2016, in the Pacífica Fernández National Highway, Puntarenas, Costa Rica. We counted all visible roadkills. Results: We recorded 56 roadkill individuals, primarily toads (Rhinella horribilis) and iguanids. Close vegetation increased the number of victims, while straight versus curved road sections did not. Conclusions: We recommend barriers, speed reducers, and suitable wildlife crossings, particularly in areas with dense vegetation close to the road.

Effect of cutting length on the asexual propagation of tacaco (Sechium tacaco; Cucurbitaceae)

José Eladio Monge-Pérez, Karen María Muñoz-López, Michelle Loría-Coto — Wed, 17 Jul 2024 00:00:00 -0600

Introduction: There is few information on the vegetative propagation of tacaco (Sechium tacaco). Objective: To evaluate the effect of cutting length on the asexual propagation of tacaco. Methods: We carried out the test in Ujarrás, Cartago, Costa Rica. We use 36 cuttings from secondary shoots, of three different lengths (long, medium and short; 12 cuttings of each length). We treated the cuttings with 10 000ppm IBA, and kept them under greenhouse conditions for 41 days. Then we transplanted them into plastic bags, and kept them under a shade house for 27 days. We evaluated the following variables: root dry weight, aerial part dry weight, aerial part dry weight/root dry weight ratio, change in height, change in number of nodes, change in number of shoots, and change in stem thickness. Results: We did not find significant differences between treatments for any of the evaluated variables. Conclusion: The length of the cutting did not significantly influence the vegetative propagation of tacaco.

First pages 16 (Jan-Dec 2024)

UNED Research Journal — Thu, 08 Feb 2024 00:00:00 -0600

Lista de revisores 2023-2024

UNED Research Journal — Tue, 17 Dec 2024 00:00:00 -0600