Artículos científicos

Permanent URI for this collection

http://localhost:4000/handle/20.500.12536/78

Browse

Now showing 1 - 20 of 77

Glyphosate Use in Forest Plantations
(2010) Kogan, Marcelo; Alister, Claudio
Under Chilean conditions the lack of weed control at forest tree establishment results in an average of at least 60% less biomass accumulation during the first year of growth of radiate pine or eucaliptus, and glyphosate offers a series of advantages in forestry weed management because its activity in both herbaceous weed groups, monocots and dicots, as well as annuals, biennials and perennials. Also, its efficacy in woody undesirable vegetation makes glyphosate a very important herbicide that can be applied to control herbaceous and woody weeds as pre-planting and during the second or third years of trees growth as strip applications. The aim of this review is to discuss the main uses of glyphosate in reforestation worldwide, during the first 2 yr after tree establishment, as broadcast application over the top of the forest trees and the most important factors that could affect glyphosate efficacy as a forest herbicide, like weed growth stage, application technique, volume and water quality, rainfastness, dew effect and the use of extra adjuvant with formulated glyphosate.
Effects of physicochemical soil properties of five agricultural soils on herbicide soil adsorption and leaching
(2011) Alister, Claudio; Araya, Manuel; Kogan, Marcelo
Once pesticides reach the soil, there are several factors that affect their soil behavior. To identify the principal soil and herbicide properties that control their adsorption and leaching, a study of five Chilean agricultural and forest soils was performed. Simazine, diuron, terbuthylazine and MCPA were applied to the top of 45-cm tall by 12-cm diameter disturbed soil columns, filled with either an Andisol, Ultisol, Entisol or one of two Inceptisol soils. After herbicide applications, each lysimeter received 24 mm of simulated rain every 24 hours for five days. Once water percolation stopped, the lysimeters were divided into five sections and herbicide concentrations were quantified using High Pressure Liquid Chromatography. Relationships between soil physicochemical properties, herbicide sorption (adsorption and desorption) and herbicide leaching were determined. All herbicides exhibited the least depth reached from the Andisol soil (10 cm) and the highest from the Ultisol soil (45 cm). The principal soil property that affected herbicide adsorption was the soil organic carbon content, specifically the fulvic acid-humins fraction. Soil leaching was related to the inverse of soil adsorption (1/Kd), cation exchange capacity, humic substances content and herbicide pKa. These results suggest that it is possible to develop simple quantitative models to predict the soil-leaching properties of pesticides.
Using penoxsulam ALS inhibitor as a broad-spectrum herbicide in Chilean rice
(2011) Kogan, Marcelo; Gómez, Patricio; Fischer, Albert; Alister, Claudio
The continuously-flooded rice production system in Chile has selected highly competitive aquatic weeds selection capable ofreducing paddy yields by 25 to 50%. Penoxsulam is a broad-spectrum triazolopyrimidine (ALS inhibitor) commercially introduced in Chile in 2006, where Alisma plantago aquatica hads already evolved resistance to sulfonylurea herbicides (SU). Several field trials with water seeded rice were conducted during 2003 and 2004 in Chile to determine efficacy, timing of application, spectrum of control, and control of SU-resistant A. plantago aquatica with the herbicide penoxsulam, either in single applications or in sequence with other herbicides. Penoxsulam was applied a) 12 days after seeding (DAS) into the water (IW), b) in postemergence after draining the water from field (ADW) at 35 DAS or c) IW followed by ADW applications of MCPA, cyhalofop, bentazon, or triclopyr. Penoxsulam was tested at 20, 30, and 40 g a.i. ha-1. Comparisons were made with recommended rates of other IW treatments (metsulfuron, bensulfuron and cyclosulfomuron) and sequential applications of molinate (IW) followed by ADW applications of MCPA, cyhalofop, bentazon, or triclopyr. One IW penoxsulam application was sufficient to achieve broad-spectrum control: Echinochloa spp. (100% control), A.plantago-aquatica (80 to 100%), Schoenoplectus mucronatus (50 to 80%), and Cyperus difformis (80 to 100%). Rice yields in penoxsulam-treated plots were 30 to 56% higher than in the untreated controls. Yields with penoxsulam IW (all rates) were similar (P>0.05) to those obtained using molinate (IW) followed by ADW applications of bentazon or MCPA. Although penoxsulam is an ALS inhibitor, it controlled A. plantago-aquatica resistant to metsulfuron and bensulfuron.
Endoparasites of the kodkod, Oncifelis guigna (Carnivora, Felidae) in Chile
(2011) González-Acuña, Daniel; Moreno, Lucila; Ardiles, Karen; Flores, Marcelo; Duclos, Melanie; Kinsella, Mike
Adsorption and desorption variability of four herbicides used in paddy rice production
(2011-01) Alister, Claudio A.; Araya, Manuel A.; Kogan, Marcelo
This investigation was performed to determine the effect of physicochemical soil properties on penoxsulam, molinate, bentazon, and MCPA adsorption-desorption processes. Four soils from Melozal (35° 43' S; 71° 41' W), Parral (36° 08' S; 71° 52' W), San Carlos (36° 24' S; 71° 57' W), and Panimavida (35° 44' S; 71° 24' W) were utilized. Herbicide adsorption reached equilibrium after 4 h in all soils. The Freundlich L-type isotherm described the adsorption process, which showed a high affinity between herbicides and sorption sites mainly because of hydrophobic and H-bonds interaction. Penoxsulam showed the highest adsorption coefficients (4.23 ± 0.72 to 10.69 ± 1.58 mL g⁻¹) and were related to soil pH. Molinate showed K(d) values between 1.72 ± 0.01 and 2.3 ± 0.01 mL g⁻¹ and were related to soil pH and organic matter, specifically to the amount of humic substances. Bentazon had a high relationship with pH and humic substances and its K(d) values were the lowest, ranging from 0.11 ± 0.01 to 0.42 ± 0.01 mL g⁻¹. MCPA K(d) ranged from 0.14 ± 0.02 to 2.72 ± 0.01 mL g⁻¹, however its adsorption was related to humic acids and clay content. According to these results, the soil factors that could explain the sorption process of the studied herbicides under paddy rice soil conditions, were principally humic substances and soil pH. Considering the sorption variability observed in this study and the potential risk for groundwater contamination, it is necessary to develop weed rice management strategies that limit use of herbicides that exhibit low soil adsorption in areas with predisposing conditions to soil leaching.
Water and sediment dynamics of penoxsulam and molinate in paddy fields: field and lysimeter studies
(2011-07-15) Kogan, Marcelo; Araya, Manuel; Alister, Claudio
BACKGROUND: In Chile, rice is cultivated under water-seeded and continuously flooded conditions. Because herbicide dynamics in paddy fields and non-flooded fields is different, 3 year experiments were performed to study the dissipation of molinate and penoxsulam in water and sediment. RESULTS: In field experiments, both herbicides dissipated by 45–55% from the initial applied amounts during the first 6 h after application in all crop seasons; in lysimeter experiments, dissipation amounts were approximately 10% for penoxsulam and 16% for molinate. Penoxsulam field water DT50 values varied from 1.28 to 1.96 days during the three study seasons, and DT90 values from 4.07 to 6.22 days. Molinate field water DT50 values varied from 0.89 to 1.73 days, and DT90 values from 2.82 to 5.48 days. Sediment residues were determined 2 days after herbicide application into the paddy water, and maximum concentrations were found 4–8 days after application. In sediment, DT50 values varied from 20.20 to 27.66 days for penoxsulam and from 15.02 to 29.83 days for molinate. CONCLUSIONS: Results showed that penoxsulam and molinate losses under paddy conditions are dissipated rapidly from the water and then dissipate slowly from the sediment. Penoxsulam and molinate field water dissipation was facilitated by paddy water motion created by the wind. Sediment
Simazine transport in undisturbed soils from a vineyard at the Casablanca valley, Chile
(2013-01-20) Suárez, Francisco; Guzmán, Edwin; Muñoz, José F.; Bachmann, Jaime; Ortiz, Cristian; Alister, Claudio; Kogan, Marcelo
Simazine is a soil-active herbicide that has been applied worldwide in agricultural soils, being the second most commonly detected herbicide in groundwater and surface waters. Although its use has been restricted in many countries of Europe, it is still applied in many locations around the world in orchards, vineyards and forestry. Therefore, it is important to study its fate and transport in the environment. This paper investigates simazine transport in undisturbed bare soils from a vineyard at the Casablanca valley, Chile. In the study site, shallow groundwater tables (<1.0 m depth) and high simazine levels (>15 μg L−1) in the groundwater were observed and thus, there is potential for simazine to be transported further away through the saturated zone. The soils from the study site were characterized and the hydrodynamic transport parameters were determined. Column leaching experiments showed that the two-site chemical non-equilibrium model correctly represented simazine transport. It was found that 36.3% of the adsorption sites achieve instantaneous equilibrium and that the first-order kinetic rate of the non-equilibrium sites was 6.2 × 10−3 h−1. Hydrus 2D was used to predict the transport of simazine in the study site under natural field conditions. Simulation results showed that simazine concentrations at depths shallower than 2.1 m are above the maximum contaminant level of 4 μg L−1 (defined by the U.S. Environmental Protection Agency). The timing of herbicide application was found to be important on simazine leaching and the main processes involved in simazine transport were degradation and adsorption, which accounted for 95.78 and 4.19% of the simulated mass of pesticide, respectively. A qualitative agreement in the timing and magnitude of simazine concentration was obtained between the simulations and the field data. Therefore, the model utilized in this investigation can be used to predict simazine transport and is a valuable tool to assess agricultural practices to minimize environmental impacts of simazine.
Competitive Strategies and Growth of Neighbouring Bromus valdivianus Phil. and Lolium perenne L. Plants Under Water Restriction
(2013-05) López, F.; Kemp, P. D.; Dörner, J.; Descalzi, C. A.; Balocchi, O. A.; García, S.
Often perennial pastures have to tolerate soil water restriction during summer, which can affect the relative abundance of the most desired species. In the south of Chile, Bromus valdivianus and Lolium perenne are preferred species. The competitiveness of B. valdivianus and L. perenne was evaluated when sown in pots in a glasshouse as monocultures or a mix (50/50 %) with restricted water availability. The water restriction treatments were as follows: 80–85 % field capacity (FC), 45–50 % FC and 20–25 % FC, maintained for 1196 growing degree days. For both species, dry matter (DM) accumulated per plant and per pot decreased similarly with increasing water restriction, but at tiller level, resource allocation differed, for B. valdivianus root growth was accentuated over aerial development, but this was less so for L. perenne. The foliage mass per tiller for B. valdivianus decreased relatively more than that for L. perenne with increasing water restriction. As monocultures, B. valdivianus produced larger tillers than L. perenne, such that B. valdivianus tillers had 2.2 times greater lamina mass, 3.6 times more leaf area and 2.5 times greater root mass than those of L. perenne. However, L. perenne produced a larger number of smaller tillers that enabled foliage, root and total mass at plant level, to be similar to that of B. valdivianus. Within the mixed pasture, L. perenne tiller density increased compared with when grown as a monoculture, but not for B. valdivianus. The results of the study suggested that L. perenne and B. valdivianus have differences in growth strategies that allow them to survive under environmental stress and competition. Competitiveness increased for L. perenne aboveground without water restriction and that for B. valdivianus increased belowground as water restriction was increased.
Quantifying effects of irrigation and soil water content on electricalpotentials in grapevines (Vitis vinifera) using multivariate statisticalmethods
(2014-05-20) Gil, Pilar M.; Saavedra, Jorge; Schaffer, Bruce; Navarro, Rosa; Fuentealba, Claudia
Several studies have shown that physiological responses in plants, including fruit crops, are associated with changes in electrical potentials (EP), but it is often difficult to statistically quantify these responses. This study tested the effects of irrigation on EP in grapevines (Vitis vinifera), taking into account vapor pressure deficit (VPD) and position of electrodes along the stem by using multivariate analytical methods and a suite of statistical pretreatments. In two separate experiments, plants were exposed to one of two irrigation treatments in a greenhouse: (T1) irrigation once per day (Experiment 1), or no irrigation (Experiment 2); or (T2) irrigation three times or twice per day (Experiments 1 and 2, respectively). In each experiment, EP at three positions along the stem, soil (potting medium) water content, and VPD were continuously measured. In Experiment 2, stomatal conductance (gs) and stem water potential (SWP) were also measured for plants in each irrigation treatment as indicators of plant water status. Data were analyzed by Principal Component Analysis (PCA) to determine the effects of irrigation treatment on EP and difference in EP between pairs of electrodes (ΔEP) at various locations along the stem. Data were also analyzed by partial least squares (PLS) analysis to determine if EP or ΔEP could be used as predictors of changes in soil water content due to different irrigation treatments. Significant differences in soil water content due to irrigation treatments could be readily detected by difference in EP or ΔEP using PCA with Orthogonal Signal Correction pre-processing. Also, PLS showed that differences in soil moisture can be predicted by EP and/or ΔEP measurements at specific locations along the stem. Thus, the use of multivariate statistical methods was effective for relating EP and ΔEP measurements in grapevines to soil moisture due to differences in irrigation.
Utilización de los Índices de Hábitat Fluvial, Bosque de Ribera y Macrófitas para la Determinación de Calidad del Recurso Hídrico del Estero Catapilco, Región de Valparaíso
(2015-03-02) Silva Haun, Rodrigo; Arancibia Fortes, Javier
El Estero Catapilco está ubicado en Chile central. Su alimentación corresponde a un régimen 100% pluvial, desarrollándose flora mediterránea en su cauce (bosque esclerófilo e hidrófilo). La intervención antrópica ha modificado la vegetación ribereña, el caudal disponible y la calidad del agua. Para caracterizar la calidad del recurso hídrico se estableció seis (6) estaciones a lo largo de la cuenca, aplicando en cada una de ellas el Índice de Hábitat Fluvial, Índice de Calidad Bosque de Ribera y el Índice de Macrófitas. Dichos resultados fueron correlacionados utilizando la metodología de Spearman (1904) con los análisis físicos y químicos realizados al agua. El análisis de la calidad del agua del Estero Catapilco mostró que estas no se encontraban en la mejor condición. La correlación con muestreos físicos y químicos de las aguas, mostró marcadas diferencias entre ambas metodologías. Estas situación puede deberse a la baja diversidad de especies nativas y un número importante de especies introducidas, lo que incide directamente con los valores entregados por los índices. Asimismo se observó que los cambios en el uso de suelo, aumento de plantaciones forestarles, está influyendo en la cantidad del recurso hídrico disponible en la cuenca.
Situación del Crowdfunding como mecanismo para la financiación de PyMEs en Colombia
(2017) Jiménez Sánchez, Jorge Iván; Rojas Restrepo, Farley Sary; Ramírez Tapias, Diego Alejandro
Esta investigación analiza la situación de Crowdfunding en Colombia, modalidad que tiene como objeto el financiamiento de proyectos e ideas, se utiliza la Internet para tal fin, hay cuatro modalidades: donación, recompensa, préstamo e inversión, se requiere contar una normatividad para las dos últimas, ya que en virtud de la ley vigente no es lícito desarrollarlas en el País.
Herramienta “Gerencia del Valor” para el diagnóstico financiero en las Empresas Sociales del Estado
(2017) Jiménez Sánchez, Jorge Iván; Rojas Restrepo, Farley Sary; Ramírez Tapias, Diego Alejandro
La importancia de las Empresas del Estado radica en el carácter social que cumplen en la sociedad; la atención en salud presenta muchos problemas y requiere ser mejor administrada, se propone aplicar herramientas como la “Gerencia del Valor” la cual se basa en el calculo de indicadores orientados a crear valor, lo que ayuda a un mejor desempeño. Igualmente, conceptos modernos como la “Nueva Gestión Pública”, invitan a los países a superar los sistemas burocráticos de antaño, en búsqueda de una mejor eficiencia y eficacia en la prestación de servicios y el manejo adecuado de los recursos públicos.
Evaluation of sustainability and the impact of the agriculture styles of the chilean coastal dry lands
(2017) González Ulibarry, Paco; García Elizalde, Pedro; Gastó Corderch, Juan; De Kartzow Garcia, Alejandro; Obando-Ulloa, Javier Mauricio
Agriculture has been progressing continuously, from the use of free natural resources to the fossil fuels as energy sources. Even though agriculture depends mainly on ecosystem resources and services, its development has been apparently centered only on yield, not considering neither the ecological value of the negative externalities nor the decapitalization of the resources that influence sustainability. Thus, the information on the evaluation of the sustainability on different agriculture styles is scarce or almost null. This investigation evaluates the sustainability in different agriculture styles (intensive horticulture, traditional farm and self-sustaining horticulture) established in Hualqui (Region of Biobío, Chile), through the energy flows present on each style to measure the impact generated on the land. The results revealed that the self-sustaining horticulture style showed a higher sustainability compared to the traditional farm and intensive horticulture style. These results can contribute to the public, policies to reorient the action strategy to encourage the sustainability in the different agriculture styles.
A Spin / Promela Application for Model checking UML Sequence Diagrams
(2018) Vidal-Silva, Cristian; Villarroel, Rodolfo; Rubio, José Miguel; Johnson, Franklin; Madariaga, Erika; Campos, Camilo; Carter, Luis
UML sequence diagrams usually represent the behavior of systems execution. Automated verification of UML sequence diagrams’ correctness is necessary because they can model critical algorithmic behaviors of information systems. UML sequence diagrams applications are often on the requirement and design phases of the software development process, and their correctness guarantees the accurate and transparent implementation of software products. The primary goal of this article is to review and improve the translation of basic and complex UML sequence diagrams into Spin / Promela code taking into account behavioral properties and elements of combined fragments of UML sequence diagrams for synchronous and asynchronous messages. This article also redefines a previous proposal for a transition system for UML sequence diagrams by specifying Linear Temporal Logic (LTL) formulas to verify the model correctness. We present an application example of our modeling proposal on a modified version of a traditional case study by using UML sequence diagrams to translate it into Promela code to verify their properties and correctness.
Aspect-Combining Functions for Modular MapReduce Solutions
(2018) Vidal-Silva, Cristian; Villarroel, Rodolfo; Rubio, José Miguel; Johnson, Franklin; Madariaga, Érika; Urzúa, Alberto; Carter, Luis; Campos-Valdés, Camilo; López-Cortés, Xaviera A.
MapReduce represents a programming framework for modular Big Data computation that uses a function map to identify and target intermediate data in the mapping phase, and a function reduce to summarize the output of the map function and give a final result. Because inputs for the reduce function depend on the map function’s output to decrease the communication traffic of the output of map functions to the input of reduce functions, MapReduce permits defining combining function for local aggregation in the mapping phase. MapReduce Hadoop solutions do not warrant the combining functioning application. Even though there exist proposals for warranting the combining function execution, they break the modular nature of MapReduce solutions. Because Aspect-Oriented Programming (AOP) is a programming paradigm that looks for the modular software production, this article proposes and apply Aspect-Combining function, an AOP combining function, to look for a modular MapReduce solution. The Aspect-Combining application results on MapReduce Hadoop experiments highlight computing performance and modularity improvements and a warranted execution of the combining function using an AOP framework like AspectJ as a mandatory requisite.
Barreras legales para la introducción del Crowdfunding en Colombia: análisis comparativo con España Legal barriers
(2018) Jiménez Sánchez, Jorge Iván; Rojas Restrepo, Farley Sary; Ramírez Tapias, Diego Alejandro
El artículo en primera medida describe el crowdfunding y sus diversas clasificaciones, las bondades en su utilización y su potencial para impulsar nuevas ideas de negocio. En segunda medida, analiza la situación legal de esta modalidad en Colombia, comparando su legislación con España, país que presenta un desarrollo más avanzado de esta fuente de financiación.
Resolución del problema de balanceo de mallas curriculares mediante algoritmo de luciérnagas
(2018) Rubio, José Miguel; Soto, Ricardo; Jorquera, Hernán; Aguilera, Jorge; Vidal-Silva, Cristian
En este artículo se propone resolver el problema de balanceo de mallas curriculares (BACP), que consiste en la asignación de una carga académica balanceada a periodos académicos de un plan de estudios, mediante una técnica de optimización basada en la atracción de las luciérnagas (FA). Se resolverán tanto instancias de prueba como instancias reales con el fin de medir el rendimiento del algoritmo y entregar un sistema que permita simplificar el proceso de diseño de una malla curricular en las Instituciones de Educación Superior. Los resultados obtenidos muestran que el algoritmo FA tiene una convergencia bastante rápida y encuentra el óptimo conocido en la mayoría de las pruebas realizadas.
Dinámica metapoblacional, ocupación espacial y migración en bivalvos de importancia comercial: el caso de la almeja Tawera gayi (Bivalvia: Veneridae) en el Mar Interior de Chiloé
(2018) Figueroa Fábrega, Luis; Bravo Samaha, Javiera; Silva Haun, Rodrigo; Padilla, Tiare
Tawera gayi (Hupe, 1854), es un molusco bivalvo conocido comúnmente como Juliana, cuya extracción comercial en Chile se concentra tanto en la zona norte del mar interior de Chiloé cómo en las inmediaciones de las islas Desertores. Según las estadísticas pesqueras, los desembarques han disminuido progresivamente en el último tiempo, para lo cual se han esgrimido razones relacionadas tanto con el mercado, la sobreexplotación del recurso y a la no inclusión de la conectividad espacial de los distintos bancos locales en el manejo pesquero. Por lo que el estudio de la dinámica de metapoblaciones (i.e. la variación temporal de la ocupación de los parches) puede ser una herramienta útil para comprender los patrones de abundancia de aquellas especies que presentan una alta conectividad espacial. En el presente trabajo se realizaron simulaciones para dos escenarios descritos en la zona, para dar respuesta a una serie de interrogantes relacionadas con la conectividad espacial entre bancos, los efectos de la disminución en la conectividad y el grado de incidencia de algunos de ellos. Los resultados nos indican que, al disminuir la disponibilidad de larvas por perdida de la fracción reproductiva, se reduce la probabilidad de colonización, afectando además la probabilidad de dispersión y la incidencia entre bancos cambiando la dinámica de la metapoblación. En una perspectiva temporal, se constato que la población de Juliana paso de tener una alta conectividad entre los bancos a una condición de auto reclutamiento de algunos bancos particulares de mayor tamaño, tal como se ha visto en otras almejas de importancia comercial. Por consiguiente, es fundamental considerar la conectividad espacial en el manejo pesquero, considerando además los efectos sinérgicos que la extracción de especies de interés comercial pueda generar en los ecosistemas marinos del mar interior de Chiloé.
Propuesta de Modelo de Características con Interfaz de Punto de Unión para el Modelamiento de Líneas de Productos de Software
(2018) Vidal-Silva, Cristian; Bustamante, Miguel A.; Rubio, José Miguel; Carter, Luis
En búsqueda de una nueva metodología de desarrollo de software modular, este trabajo propone MC JPI, esto es, Modelos de Características (MC) con Interfaz de Punto de Unión (JPI del inglés Join Point Interface) de Programación Orientada a Aspectos (POA) como base de la metodología Programación Orientada a la Característica (FOP) + JPI. Así, este trabajo describe ventajas y detalles de FOP y POA JPI como paradigmas individuales y de su simbiosis para la producción de software modular. Como aplicación ejemplo, se utiliza MC JPI sobre un ejemplo clásico de FOP para visualizar componentes propios de MC tradicionales, y asociaciones o restricciones cruzadas especiales entre características. Adicionalmente, este trabajo describe las ventajas de MC JPI y las diferencias respecto a algunos trabajos de investigación anteriores para apoyar principios de modelado orientados a aspectos propios de JPI. Se concluye que JPI permite una modularización sobre modelos de características, y así este enfoque de simbiosis JPI + FOP parece prometedor.
Lagrangian Relaxation for an Inventory Location Problem with Periodic Inventory Control and Stochastic Capacity Constraints
(2018) Araya-Sassi, Claudio; Miranda, Pablo A.; Paredes-Belmar, Germán
We studied a joint inventory location problem assuming a periodic review for inventory control. A single plant supplies a set of products tomultiple warehouses and they serve a set of customers or retailers.The problem consists in determining which potential warehouses should be opened and which retailers should be served by the selected warehouses as well as their reorder points and order sizes while minimizing the total costs. The problem is a Mixed Integer Nonlinear Programming (MINLP) model, which is nonconvex in terms of stochastic capacity constraints and the objective function. We propose a solution approach based on a Lagrangian relaxation and the subgradient method. The decomposition approach considers the relaxation of different sets of constraints, including customer assignment, warehouse demand, and variance constraints. In addition, we develop a Lagrangian heuristic to determine a feasible solution at each iteration of the subgradientmethod.The proposed Lagrangian relaxation algorithm provides low duality gaps and near-optimal solutions with competitive computational times. It also shows significant impacts of the selected inventory control policy into total system costs and network configuration, when it is compared with different review period values.

Browse

Browsing Artículos científicos by Issue Date

Results Per Page

Sort Options