Aquiles Darghan

• Phd in statistics
• teacher. Multivariate statistics and experimental design at National University of Colombia

The physiopathy of the oil palm (Elaeis guineensis Jacq.) called “duster” whose causal agent is unknown is characterized by abnormality in the development of the leaf and longitudinal chlorotic streaking parallel to the midrib. Dissections of plants affected by this disease show no signs at first sight. Therefore, the objective was to explore and e...

Monitoring and quantifying soil organic carbon content in different landscapes at different sampling depths is crucial to assessing the quality of soil, water and the functionality of the ecosystems that are established there. Monitoring results can guide practices that could be adopted to improve soil organic carbon storage and thus enhance and di...

In recent years, statistical methods have been developed that include spatial considerations, for example, those that incorporate data with georeferencing. The descriptive part of geographical information systems currently provides many visualization and analysis tools; however, in terms of analysis, these systems are still quite limited, therefore...

The use of computational tools to describe some processes of crop growth has evolved in recent decades and remains an area of active research, where more and more applications are incorporated with the integration of a greater number of mathematical tools, statistics, and computational calculation efficiency, simplifying the tasks of modeling and v...

Background Overweight and obesity, high blood pressure, hyperglycemia, hyperlipidemia, and insulin resistance (IR) are strongly associated with non-communicable diseases (NCDs), including type 2 diabetes, cardiovascular disease, stroke, and cancer. Different surrogate indices of IR are derived and validated with the euglycemic–hyperinsulinemic clam...

Phureja Group potato is endemic and important for northern Andean countries such as Colombia, Ecuador and Venezuela, where it is grown over a wide range of elevation. The objective of the study was to compare the biomass accumulation of five potato cultivars in three contrasting environments in elevation from a latent response variable of vector na...

Pastures dedicated to cattle production in Venezuela have a low crude protein concentration. One of the nutritional strategies to correct the forage protein deficit is using non-protein nitrogen in the diet. To evaluate the effect of two non-protein nitrogen sources on the metabolic profile of lactating dairy cows, 31 F1 Holstein × Zebu multiparous...

With the new technologies in plant phenotyping, robust and reliable tools are still required to analyze large-scale and multivariate datasets. The RankspeQ is a novel R package developed to evaluate genotype performance and to support selection-driven decisions based on leaf traits and environment-related variables measured by the MultispeQ device....

The phenological patterns of coffee flowering in Colombia have typically been studied in a descriptive way, with knowledge from an inferential perspective being scarce. The present study evaluated the effect of geographic location and accession on the floral patterns and phenological descriptors of Coffea arabica L. Fifteen accessions from the Colo...

Plant available water storage capacity is a vital soil property for vegetation and soil hydrological processes. Different investigations focused on evaluating the influence of rock fragments on the soil plant water storage capacity usually don’t involve the spatial component. This work spatially modelled the available water storage capacity for pla...

In recent years, statistical methods involving spatial considerations have been developed, for example, those incorporating data with some type of georeferencing. The descriptive part of geographic information systems currently provides many visualization and analytic tools; however, the latter is still quite limited. In this sense, research of a s...

The capacity of soil to sequester carbon (C) is a key process that promotes the reduction of CO2 in the atmosphere. Soils can absorb as much as 20% of anthropogenic carbon emissions, which can contribute to mitigate climate change. This capacity relies on the organo-mineral association, which includes different minerals, Fe and Al oxides, which hav...

Temporal distribution of Botrytis cinerea and its relationship to the production of strawberries (Fragaria × ananassa Duch., Monterrey variety) subjected to biological treatments with microbial antagonists Distribución temporal de Botrytis cinerea y su relación con la producción de fresas (Fragaria × ananassa Duch., variedad Monterrey) sometidas a...

Oil palm is the second most cultivated oilseed crop in the world after soybeans, with more than 23 million hectares cultivated worldwide; it has become crucial for the economy of many countries. In Colombia, it is one of the most developed agricultural sectors, and every year the sector promotes the development of technologies that lead to greater...

The development of online tools has provided solutions to different activities, including academia. The Agronomy program at the Universidad Nacional de Colombia has updated its competency-based teaching approaches by encouraging the development and application of computational tools for analysis, modeling, and interpretation of data. A registration...

Cocoa is a staple crop for small farmers, has been promoted as an alternative crop to Erythroxylum coca . Some soils in the Colombian cocoa zone seem to accumulate high levels of Cd in the beans. To comprehend the relationship between different Cd forms and their phytoavailability in the beans, cocoa-producing farms were sampled located in Yacopi m...

Bus rapid transit (BRT) systems have generated a tremendous positive change in road safety and public transport operations. However, the literature reveals the need for a quantitative preventive risk evaluation from a microscopic approach, integrated with outcomes from accident-based and behavioral research, which is the primary purpose of this pap...

Water is one of the most determining factors in obtaining high yields in oil palm crops. However, water scarcity is becoming a challenge for agricultural sustainability. Therefore, when the environmental supply of water is low, it is necessary to provide it to crops with the highest degree of efficiency. However, although irrigation technologies ar...

Infiltration depends on the surface conditions of the soils, such as surface rock fragments cover and some of the properties of the matrix such as total porosity. Research reports inconclusive results regarding the influence of rock fragment cover on soil water infiltration that usually does not involve the spatial component in the analyses. The ob...

Research has been carried out to evaluate the effects of rock fragments on the hydraulic conductivity of soils; however, spatial relationships have not been established in analyses of such effects. In the present investigation, the properties of the soil were determined, as well as the proportion of the different fractions of rock fragments, and th...

Botrytis cinerea, el agente causal de la enfermedad del moho gris, es uno de los patógenos más destructivos del cultivo de fresa, tanto en el desarrollo vegetativo como en poscosecha. El control de este patógeno es complejo, debido a su agresividad y capacidad de atacar e infectar diversos tejidos de la planta y se basa, principalmente, en el contr...

The Andean blueberry is a high-Andean wild fruit species consumed in fresh or processed form that has high potential due to its antioxidant capacity. Leaf area describes the photosynthetic capacity of plants and is employed as a variable in multiple physiological studies; however, in Andean blueberry (Vaccinium meridionale Swartz), its direct measu...

The urban structure of a city, defined by its inhabitants, daily movements, and land use, has become an environmental factor of interest that is related to traffic accidents. Traditionally, macro modeling is usually implemented using spatial econometric methods; however, techniques such as support vector regression have proven to be efficient in id...

Introduction Evaluations of interspecific hybrids are limited, as classical genebank accession descriptors are semi-subjective, have qualitative traits and show complications when evaluating intermediate accessions. However, descriptors can be quantified using recognized phenomic traits. This digitalization can identify phenomic traits which corres...

Saturated hydraulic conductivity (Ks) is an important soil variable. Multiple investigations have analysed the influence of rock fragments on saturated hydraulic conductivity, but they hardly involve the spatial component. This research spatially modelled the Ks and its relationship with the contents of rock fragments, organic carbon, and total por...

In the banana crop, leaf area is a fundamental trait for production; however, monitoring this variable during a cycle is difficult due to the structural characteristics of the plant, and a method for its determination is necessary. Therefore, the objective of this research was to propose a model for estimating total leaf area by measuring the cross...

La capacidad de agua disponible para las plantas es una propiedad del suelo vital para la vegetación y algunos procesos hidrológicos del suelo; sin embargo es afectada por la variabilidad espacial de algunas propiedades edáficas. Diversas investigaciones han analizado la posible influencia de los fragmentos de roca sobre el agua disponible para las...

Morphometric analyses have great potential for application in fruit crops, especially in the construction of indices that can be linked to biophysical and/or biochemical quantities of a physiological nature. For example, in peaches, it is convenient to establish quality attributes for harvest or postharvest, where usually the sigmoidal or double si...

The production of Voluntary Geographic Information has been growing considerably and continues to be an active area of research. However, the lack of knowledge about the quality of information generated on a voluntary and participatory basis raises challenges and questions about its use. In the review carried out for the Colombian case, no studies...

Background: Changes in global and local environmental variables condition the distribution and density of disease vectors. This study aimed to estimate the relationship between the entomological indicator of immature and adult forms of the Aedes aegypti mosquito per unit area, the environmental variables of temperature, precipitation, and relative...

Aim of study: Our main objective was to take advantage of the ECa information that the EM38-MK2 sensor records simultaneously at two relative depths for modeling using spatial regression and the subsequent blocking of the conductivity estimate values, incorporating elevation. Area of study: A 23.1-ha field located in the municipality of Puerto Lóp...

In experimental trials, it is usually of interest to give special regard to the response of experimental units at the edges, since it is well known that the performance of these can be greater than that of the rest of the units due to having less competition from neighboring units. When treatments are available, it is possible that the differences...

Infiltration depends on the surface conditions of the soils, such as the surface covering of rock fragments and some of the properties of the matrix such as total porosity. Research reports inconclusive results regarding the influence of rock fragment cover on soil water infiltration that usually does not involve the spatial component in the analys...

One of the basic principles of experimental design is blocking, which is an important factor in the treatment of the systematic spatial variability that can be found in the edaphic properties where agricultural experiments are conducted. Blocking has a mitigating or suppressing effect on the spatial dependence in the residuals of a model, something...

A new physiopathy in oil palms that has been called "duster" for which at present no causal agent is known, is gaining interest in agronomic research. In 2015 we carried out a count of reproductive structures to evaluate the severity in genetic materials of three different origins in a plantation in Colombia. The aim was to determine the possible r...

One of the criteria to select granular materials for road construction is the grain size distribution. Selected materials will compose the unbound layers of pavement structures, which support the traffic loads. This paper aims to present an approach for validating the compliance of grain size distribution of three different granular materials accor...

The generation of sludge as anthropic waste is a fundamental pollution problem. However, its conversion to biochar can be an alternative to conventional fertilization for its management and use in agriculture. In this research, we evaluated the effect of the application of different doses of dry sludge (DS) and biochar of pyrolyzed sludge (PS) on t...

The generation of sludge as anthropic waste is a fundamental pollution problem. However, its conversion to biochar can be an alternative to conventional fertilization for its management and use in agriculture. In this research, we evaluated the effect of the application of different doses of dry sludge (DS) and biochar of pyrolyzed sludge (PS) on t...

This paper presents the findings of a comparative road safety assessment between an existing two-lane roundabout and proposed basic turbo-roundabout, both designed for the same intersection, to determine which one is safer, based on traffic conflicts and surrogate safety measures.We performed microsimulation models in VISSIM to replicate the field-...

La estimación de los recursos del suelo a una escala diferente en las que se hacen las observaciones es un problema de importancia que sigue generando investigaciones relacionadas. Un aumento en la escala significa un aumento en la variación del parámetro, y esto puede causar problemas al interactuar con la no linealidad en un proceso o modelo. Cam...

El disturbio del plumero en palma de aceite se caracteriza por una anormalidad en el desarrollo del área foliar, el amarillamiento de las hojas jóvenes y el rayado clorótico longitudinal paralelo a la nervadura central. En esta investigación se determinó el área foliar de la hoja 17, el área foliar específica, los contenidos de clorofilas y la masa...

Uno de los principales desafíos que enfrentan los mejoradores es la respuesta diferencial de los genotipos de un entorno a otro, conocida como la interacción genotipo × ambiente (GxE). El procedimiento óptimo restringido de máxima verosimilitud/mejor predictor imparcial lineal (REML / BLUP) permite la estimación simultánea de parámetros genéticos y...

Microwave-assisted extraction was applied for extracting phenolics from the Sacha Inchi shell. Response surface methodology was used to estimate the optimal operating conditions. A Box-Behnken design was employed to investigate the effects of the microwave power (500, 1000, and 1500 W), ethanol concentration (E30, E60, and E90 %, v/v), and extracti...

This study develops an indirect method for the estimation of surface soil moisture (SM) by means of monitoring in situ soil water potential. Field work was carried out in ten sampling units selected according to coverage, soil, and topographic factors. Relative humidity and soil temperature were hourly measured to assess the soil–water potential th...

Selection of granular materials is a key factor for road construction, as well as the pavement performance during its operation. This paper introduces the implementation of the profile analysis as a modality of repeated measures to compare the grain size distribution of granular bases against the parameters of the road construction guidelines. The...

The low fertility of soils of the eastern plains of Colombia makes it necessary to search for methods of improving different soil properties. Fertile soils increase yields of different crops in the region, and particularly agroforestry agroecosystems will increase wood volume. Including stabilized waste residues such as biochar will probably increa...

The use of raw materials of Jatropha curcas L. to produce biofuel is of increasing interest in Colombia; little information is available on this species as a crop. This research evaluated plant height (Hp) and basal stem diameter (BSD) of J. curcas as affected by different rates of nitrogen (N) and potassium (K) during the first 435 days of growth...

Echinochloa colona (L.) Link is one of the most troublesome weed species in rice (Oryza sativa L.) crops. Despite numerous cases of herbicide resistance in E. colona worldwide, in Colombia the reports are scarce and most of them dating from over two decades ago. To screen the resistance of E. colona to bispyribac-sodium, cyhalofop-butyl and quinclo...

Because of the high susceptibility in strawberry fruits to attacks from pests and diseases, a large amount of pesticides is applied during the crop cycle and harvest period. The improper use of these substances can generate residues in agricultural products that pose a risk to human health. The objective of this study was to determine and compare p...

Gestation is a diabetogenic state due to insulin resistance. Pregnant women with higher insulin resistance are at risk of developing preeclampsia and vascular dysfunction. Fasting glucose to insulin ratio (G0/I0) and Fasting Insulin Resistance Index (FIRI = (G0 x I0)/25) are surrogate indices of insulin sensitivity of the euglycemic-hyperinsulinemi...

Because of the high susceptibility in strawberry fruits to attacks from pests and diseases, a large amount of pesticides is applied during the crop cycle and harvest period. The improper use of these substances can generate residues in agricultural products that pose a risk to human health. The objective of this study was to determine and compare p...

Cadmium (Cd) is a highly toxic heavy metal that can cause harmful effects in soils, plants, micro-organisms and human beings. Plants absorb Cd from available forms in the soil. In cocoa crops of Latin America, higher levels of Cd than those allowed by international regulations on processed foods frequently have been reported. Consequently, close mo...

The aim of this study was to characterize the quality of peach fruits Jarillo cv., produced under the conditions of altitude tropical climate in three locations: Pamplona, Chitagá and Pamplonita, in Northern Santander, Colombia. Ten trees were sampled by the conditioned latin hypercube method and eight growing fruits with physiological state of mat...

Metabolic changes have been correlated with adverse pregnancy outcomes. The aim of the present study is to determine the TyG and TG/HDL-c indices in a cohort of healthy pregnant ( n=142 ), preeclamptic ( n=18 ), and healthy nonpregnant women ( n=56 ). Preeclamptic women were selected from the same cohort. Pregnant women were followed during three p...

The supplementary word file contains five supplementary tables described in the text that support our results. Table 1: demographic, clinical, and biochemical characteristics of preeclamptic woman during pregnancy and three months postpartum. Table 2: demographic, clinical, and biochemical characteristics of healthy nonpregnant women. Table 3: post...

El carbono orgánico del suelo (COS) es importante en la determinación de las propiedades químicas que son fuente esencial de nutrientes para los cultivos. El estudio de su dinámica está relacionado con propiedades del suelo que sustentan los cultivos tal como la fertilidad. En este sentido, es crucial su estudio para intentar explicar los factores...

La friabilidad es un indicador importante de la calidad física de los suelos y su comportamiento está ligado a la variabilidad de otras propiedades edáficas. El objetivo de esta investigación fue evaluar la relación de la friabilidad con diferentes propiedades físicas y químicas de suelos cultivados con caña de azúcar. El muestreo de suelos se real...

This research is based on the Swedish Traffic Conflicts Technique (Hydén, 1987, p. 229), in which traffic conflicts are used as surrogates of crashes. The paper addresses a road safety assessment through a multivariate approach, based on surrogate measures of traffic conflicts, with the aim to develop a road safety index for an existing two-lane ro...

Durante el 2014 en la provincia de Pamplona, Colombia, se realizó un estudio sobre la variedad de duraznero Jarillo, con el fin de clasificar una serie de variables morfométricas distribuidos en tres fincas de diferenter al-titud (Pamplona, 2.170 msnm; Chitagá, 1.870 msnm y Pamplonita, 1.670 msnm). Para el muestreo de árboles se utilizó el hipercub...

Las enfermedades “pudrición negra del fruto” y “moniliasis” son reportadas como limitantes en plantaciones de cacao en Colombia. Fueron evaluados los patrones espaciales de incidencia para estas dos enfermedades en un cultivo de cacao durante un monitoreo de trece semanas en campo. Semivariogramas e interpolación kriging fueron usados para analizar...

Due to the demand in biofuel, the plant species that are not eatable and do not compete with traditional crops in Colombia, such as Jatropha curcas L., have become an important option. To produce more knowledge on the growth of this species, the research was carried out with different amounts of N and K fertilizers applied during the first 435 days...

The relationship between tuber growth and demand for NPK in andigena group of potato (Solanum tuberosum L. ssp. andigena) is poorly documented under conditions of the Andean region of Colombia. It is necessary to establish a specific nutrient management for high yields to changes in edaphicenvironmental supply and improve the production of Capiro a...

This work discusses in detail the parameters involved in water balance. The analysis is performed by considering the current conditions and climate change in a climatic zone that represents the arid regions of Colombia: The municipality of Uribia (desert) in the state of La Guajira. For this purpose, some climatological stations, which by their rep...

Con el objetivo de evaluar el efecto de dos fuentes nitrógeno no proteico (NNP) sobre ganancia diaria de peso (GDP), cambios en condición corporal (CCC), producción de leche total (PLT) y su composición química (proteína cruda: PCL, proteína verdadera: PVL, grasa: GL y urea: UL) en vacas lactantes, se realizó un experimento en el suroeste Venezolan...

Con el objetivo de evaluar el efecto de dos fuentes nitrógeno no proteico (NNP) sobre ganancia diaria de peso (GDP), cambios en condición corporal (CCC), producción de leche total (PLT) y su composición química (proteína cruda: PCL, proteína verdadera: PVL, grasa: GL y urea: UL) en vacas lactantes, se realizó un experimento en el suroeste Venezolan...

La friabilidad es una propiedad física esencial en el manejo mecánico del suelo y su comportamiento está asociado a la naturaleza de otras propiedades edáficas; que requiere ser estudiada de manera integral con diferentes propiedades mineralógicas, físicas y químicas. Se evaluó el efecto del dominio de los minerales arcillosos tipo 1:1 (caolinitas)...

En el presente artículo se propone una metodología rápida y sencilla para determinar colifagos sómaticos en las diferentes etapas del tratamiento de agua de una planta del Nordeste Colombiano, con el fin de verificar la calidad del proceso de potabilización. Materiales y métodos: Se empleó la técnica de filtración por membrana para obtener el conte...

An application of the score test of Rao is developed and presented for the overlap coefficient in the Draper and Guttman's model using the response surface generated by the central composite design. The score test o f Rao for o verlap m akes use o f the theory associated with the perpendicular projection operators and can be applied with different...

In some agricultural research, a treatment applied to an experimental unit may affect the response in the neighboring experimental units. This phenomenon is known as overlap. In this article, a test to evaluate this effect in the Draper and Guttman model was developed by imposing side conditions on the parameters of a two-way classification model t...

Banana production for export in the Uraba region of Colombia represents economic and social benefits for the country and demands improved agronomic management practices, especially for fertilization. The objective of this research was to evaluate the effect of different doses of nitrogen on crop development during two production cycles in order to...

In this article, an application of the score test of Rao is presented for the overlap coefficient in the Draper and Guttman's model using a two-way classification model and the imposition of restrictions on the parameters to complete the rank of the design matrix. The score test of Rao in this article involves the theory associated with the perpend...

To evaluate different protein supplements, an experiment was carried out in the western plains of Venezuela with Brahman crossbred first calf heifers. The animals (n=120) of 3 and 4 years of age, having on average 385 ± 29.4 kg BW prior calving were divided in three uniform groups by BW and time of calving and assigned to three supplements (1 kg/d)...