Ciencia en Desarrollo

Editorial: El desarrollo de la ciencia, en época de crisis

Emerging flora in gradient of mining post succession in Condoto, Chocó

Resumen Hicimos un análisis comparativo de la comunidad vegetal en tres áreas afectadas por minería y un bosque testigo en Jigualito (Condoto). Para determinar cambios en la composición y la estructura de la vegetación, seleccionamos tres minas abandonadas con temporalidades de 5, 15 y 30 años y un bosque sin historia minera. En cada área se instalaron 5 parcelas de 5 x 20 equivalentes a 500 m2, se registró y midió la vegetación presente en cada área seleccionada. En las minas abandonadas la distribución de riqueza, composición y estructura de la comunidad vegetal está condicionada por la cronología del abandono minero y la evolución de los niveles sucesionales, evidenciando el aumento de la riqueza y la disminución de las abundancias a medida que incrementó la temporalidad de cese de la actividad, favoreciendo el incremento de la diversidad y la aparición de una estructura más compleja. Por lo que se infiere que después de tres décadas, la comunidad vegetal se encuentra aproximadamente en menos de un 50% de sus condiciones iniciales en términos numéricos de composición , sin embargo, el arreglo florístico es completamente diferente al del bosque testigo, en este sentido, la actividad minera ocasiona una serie de áreas con arreglos florísticos diferentes.

Abstract A comparative analysis of the plant community was made in three areas affected by mining and a control forest in Jigualito (Condoto). To determine changes in the composition and structure of the vegetation, we selected three abandoned mines with time periods of 5, 15 and 30 years and a forest without mining history. In each area 5 plots of 5 x 20 were installed, equivalent to 500m2, the vegetation present in each selected area was recorded and measured. In abandoned mines, the distribution of wealth, composition and structure of the plant community is conditioned by the chronology of mining abandonment and the evolution of succession levels, evidencing the increase in wealth and the decrease in abundance as temporality increased of cessation of activity, favoring the increase of diversity and the appearance of a more complex structure. Therefore it can be inferred that, after 3 decades, the plant community is in approximately less than 50% of its initial conditions in numerical terms of composition, however, the floristic arrangement is completely different from that of the control forest, therefore , the mining activity causes a series of areas with different floristic arrangements.

Water physicochemical variables in The Rancheria River Delta, La Guajira, Colombia

Resumen Se caracterizó y monitoreó la dinámica espacio-temporal de variables fisicoquímicas del agua del Río Ranchería en La Guajira colombiana, se establecieron cinco estaciones de muestreo, tres en el brazo El Riíto: Desembocadura (DB), El Mirador (EM) y Villa Fátima (VF), y dos en el brazo Calancalá: Cangrejito (CG) y Valle de los Cangrejos (VC), en un año se realizaron mediciones mensuales de la temperatura, oxígeno disuelto, salinidad, turbidez, alcalinidad, dureza total, amonio, nitrito, nitrato, fosforo y relación N/P. Los resultados indican que los brazos presentan una dinámica diferente entre ellos. La salinidad aumentó durante el periodo de estudio; fue mayor en las estaciones del Calancalá; promedio de 46.72 ups. en CG, el oxígeno disuelto mostró un patrón distinto en ambos brazos, disminuyó de la época de lluvia (3.19-4.40 mg./L.) a la de sequía (2.04-3.01 mg./L.) en El Riíto, se observó lo contrario en las estaciones del Calancalá. El pH mostró una mayor tendencia en el Calancalá siendo significativamente diferentes en ambas épocas con respecto a El Riíto, la alcalinidad fue estadísticamente diferente en la época seca para ambos brazos. Las aguas de El Riíto se mostraron más turbias (61.39-81.71 ntu.) con respecto a las del Calancalá (30.02-30.17 ntu.) en la época de lluvias. Los nutrientes nitrogenados y el fosforo presentaron poca variabilidad, haciéndose más notoria durante la sequía. Se evidencia una gran variabilidad espacio-temporal de los parámetros fisicoquímicos, que distingue a los dos brazos del delta del Río Ranchería, como consecuencia de factores climáticos y puntuales de cada uno, lo que genera una heterogeneidad ambiental marcada, principalmente durante la sequía.

Abstract The spatial-temporal dynamic of physical-chemical variables of the water was characterized and monitored in the Ranchería River in the Colombian Guajira. Five sampling stations were chosen, three in the arm The Riíto: Desembocadura (DB), El Mirador (EM) and Villa Fatima (VF), and two stations in the arm Calancalá: Cangrejito (CG) and Valle de los Cangrejos (VC), monthly measurements for one year were made of temperature, dissolved oxygen, salinity, turbidity, alkalinity, total hardness, ammonium, nitrite, nitrate, phosphorus and N/P relationship. The results indicate that the arms have a different dynamics between them. The salinity increased during the study period; it was higher in the stations of the Calancalá; the highest average was recorded in CG with 46.72±13.56 ups., the dissolved oxygen showed a different pattern in both arms, decreased from the rainy season (3.19-4.40 mg./L.) to dry (2.04-3.01 mg./L.) in the Riíto, while the opposite occurred in the arm Calancalá. The pH tended to be higher in the Calancalá with respect to Riito, being significantly different in both arms in the two seasons studied; alkalinity was statistically different in the dry season for both arms. The waters of the Riíto were more turbid (61.39 -81.71 ntu.) with regard to the Calancalá (30.02-30.17 ntu.) in the rainy season. The nutrients nitrogen and phosphorus showed little variability, becoming more notorious during the dry season. A great spatio-temporal variability of the physicochemical variables was evidenced, which distinguishes the two arms of the Ranchería River Delta, as a result of climatic factors and specific features of each arm, which generates an environmental heterogeneity, mainly during the dry season.

Liquid silage of peach residues (Prunus pérsica) as an alternative for animal feed

Resumen Se evaluó la composición química y la presencia de microorganismos en ensilaje líquido de durazno (Prunus pérsica). Se utilizó un diseño completamente al azar con arreglo factorial 2*2, cuatro tratamientos con dos porcentajes de inclusión de melaza y sulfato de amonio: T1 (10% melaza - 1% SAM), T2 (10% melaza - 3% SAM), T3 (20% melaza - 1°% SAM) y T4 (20% melaza - 2% SAM), con tres repeticiones, los cuales fueron almacenados entre 17 y 19°C. Se determinó la composición físico-química del fruto, tomando valores de pH y crecimiento microbiológico, se caracterizó la morfología bacteriana en agar sangre y agar MacConkey. La evaluación organoléptica del ensilaje final se establece como BUENO según características fermentativas. El valor de proteína aumento en cada uno de los tratamientos conforme disminuía el valor de pH, asociado a altos crecimientos microbiales mejorando la proteína verdadera del alimento. Hubo crecimiento de colonias blanquecinas y lisas en Agar sangre con predominio de formas bacilares Gram + y Gram -. En Agar MacConkey crecieron colonias de color rosado - superficie lisa solo el día 0. El ensilaje líquido de durazno con la adicción de SAM aumenta los valores de proteína; y la adición de melaza mejora los parámetros fermentativos como estabilidad del pH.

Abstract The chemical composition and the presence of microorganisms in liquid silage of peach (Prunus pérsica) were evaluated. A completely randomized design with a 2 * 2 factorial arrangement, four treatments with two percentages of inclusion of molasses and ammonium sulfate was used: T1 (10% molasses - 1% SAM), T2 (10% molasses - 3% SAM), T3 (20% molasses - 1% SAM) and T4 (20% molasses - 2% SAM), with three replications, which were stored between 17 and 19 ° C. The physical-chemical composition of the fruit was determined, taking pH values and microbiological growth, bacterial morphology was characterized on blood agar and MacConkey agar. The organoleptic evaluation of the final silage is established as GOOD according to fermentation characteristics. The protein value increased in each of the treatments as the pH value decreased, associated with high microbial growths, improving the true protein of the food. There was growth of whitish and smooth colonies in blood agar with a predominance of Gram + and Gram - bacillary forms. Pink color - smooth surface colonies grew on MacConkey Agar only on day 0. Liquid peach silage with the addition of SAM increases protein values; and the addition of molasses improves the fermentative parameters such as pH stability.

Study of quantum correlations of qubits in remote cavities: biphotonic vs uniphotonic processes in each cavity

Resumen En este trabajo se estudian las correlaciones cuánticas, entrelazamiento y discordia, de dos qubits ubicados cada uno en su respectiva cavidad, las cuales interactúan con un reservorio común. Cada qubit interactúa con su respectiva cavidad mediante la emisión/absorción de dos fotones correlacionados (bi-fotón). Inicialmente, los átomos se consideran en un estado tipo Bell diagonal y las cavidades en estado vacío. Se calcula la evolución de las correlaciones y, para el modelo con interacciones bifotónicas sin pérdidas de fotones a través de la cavidad, se encuentra el efecto de congelamiento de las correlaciones. Cuando hay pérdidas unifotónicas o bifotónicas hacia el reservorio se evidencia un decaimiento de las correlaciones. Se nota que los qubits se encuentran entrelazados en un lapso de tiempo más largo cuando se considera interacciones y pérdidas bifotónicas.

Abstract The aim of this work is to study the quantum correlations, entanglement and discord, of two qubits, each one located in its respective cavity, which interact with a common reservoir. Each qubit interacts with its own respective cavity through the emission/absorption of two correlated photons (bi-photon). Initially, the atoms are considered in a type of Bell-diagonal state and the cavities in the empty state. The evolution of the correlations is calculated and, for the model with biphotonic interactions without losses of photons through the cavity, the freezing effect of the correlations is found. When there are uniphotonic or biphotonic losses toward the reservoir, a decay of the correlations is evidenced. It is observed that qubits are entanglement over a longer period of time when biphotonic interactions and losses are considered.

Multi-patch and multi-group model for the transmission of the malaria

Resumen La malaria es una enfermedad potencialmente mortal causada por parásitos transmitidos a los humanos por la picadura de mosquitos hembra infectados del género anopheles. Analizar el efecto de la movilidad y el hecho de que existen individuos que responden de manera diferente a la enfermedad puede aportar en la planeación de estrategias para evitar la propagación. Teniendo en cuenta lo anterior se propone estudiar la dinámica de la malaria considerando que los individuos pertenecen a un grupo determinado y se distribuyen en parcelas disyuntas que están conectadas de algún modo. Para esto, se plantea un modelo multiparche y multigrupo utilizando como base el modelo de Ross-Macdonald, en el cual se incorpora la movilidad desde el enfoque lagrangiano donde todos los individuos pertenecen a un grupo específico pero pasan parte de su tiempo en un número arbitrario de parches. El análisis cualitativo se realiza con base en el número reproductivo básico dando como resultado que la movilidad de las poblaciones de humanos y mosquitos divididas en grupos cambia la dinámica de la enfermedad.

Abstract Malaria is a potentially fatal disease which is caused for parasites transmitted to humans by the bite of female infected mosquitoes of the anopheles gender. Analyzing the effect of mobility and the fact that there are individuals who respond differently to the disease can contribute to the planning of strategies to prevent the spread. In view of the above, it is proposed to study the dynamics of malaria considering that individuals belong to a specific group and are distributed in disjoint plots that are connected in some way. For this, a multipatch and multigroup model is proposed using the Ross-Macdonald model as a basis, in which mobility is incorporated from the Lagrangian approach where all individuals belong to a specific group but spend part of their time in an arbitrary number of patches. The qualitative analysis is performed based on the basic reproductive number and the results showe that the mobility and dividing the population of humans and mosquitoes into groups changing the dynamics of the disease.

Common reactions of furfural to scalable process of residual biomass

Abstract Energy and the environment will always play key roles in society. The climate emergency cannot be ruled out to enable the transition for a clean energy future. Currently, non-renewable energy resources are declining, therefore is important to continuously explore renewable resources. Biomass is a renewable resource that can be applied to reduce climate changes and to accomplish emission policies. Cellulose is the most abundant type of biomass worldwide, which can be transformed into biofuels and potential building block platform molecules (e.g furfural) throughout biological or chemical methods. Furfural can be synthetized from cellulose using hydrolysis and dehydration reactions. Furfural has a furan ring and carbonyl functional group which makes it an important intermediary to produce higher value-added molecules at industrial level. These molecules include gasoline, diesel and jet fuel. However, furfural can also be transformed by hydrogenation, oxidation, decarboxylation and condensation reactions. The selective hydrogenation of furfural produces furfuryl alcohol, an important industrial compound, which is widely employed in the production of resins, fibers, and is considered an essential product for pharmaceutical applications. On the other hand, the oxidation of furfural produces furoic acid which is applied in the agrochemical industry, where it is commonly transformed to furoyl chloride which is finally used in the production of drugs and insecticides. The oxidation and reduction of furfural can carry out through heterogeneous and homogeneous catalysis, and biocatalysis, etc. Selectivity is an important issue in furfural hydrogenation and oxidation reactions since different products can be obtained by using monometallic or bimetallic catalysts and/or different catalyst supports. In biocatalysis approach, different enzymes, complete cells, tools of modern biotechnology, DNA sequencing, regulation of metabolic networks, overexpression of genes that encode enzymes of interest and optimization of the cellular properties of the microorganism are used. To degradate furanic compounds, improving the productivity and selectivity on a target compound. Herein, a review on the current status of furfuryl alcohol and furoic acid production from furfural by heterogeneous catalysis and biocatalysis has been studied. The stability, selectivity and activity of catalysts along with the different furfural oxidation and reduction conditions have been pointed out. Additionally, the main enzymes, microorganisms and mechanism involved in the furfural degradation process have also been discussed.

Valorization of paraffin wastes obtained from plastic pyrolysis by catalytic cracking

Resumen En esta investigación se estudió el efecto del tipo de catalizador, la temperatura de reacción y la relación másica catalizador/parafinas en la conversión de parafinas provenientes de residuos de pirólisis de plásticos, a través de craqueo catalítico. Se seleccionaron como catalizadores la Zeolita Y y la Zeolita ZSM-5, las relaciones másicas catalizador/parafina de 0.4:1 y 0.20:1, y las temperaturas de reacción de 400°C y 440°C. La reacción de craqueo de las parafinas se llevó a cabo en un reactor de lecho fijo. Por medio de análisis estadístico se determinó que el tipo de catalizador presenta el efecto más significativo al obtener un rendimiento promedio de 27.43% utilizando la Zeolita ZSM-5, en contraste con la Zeolita Y se obtuvo un 13.10%. Se determinó que se obtiene 1.2% más de rendimiento al utilizar la temperatura de 400°C respecto a la de 440°C. La relación másica catalizador/parafina no afecta de manera significativa el rendimiento. Según los análisis por cromatografía de gases, se esperaría que de este producto líquido obtenido se puedan obtener productos similares al diésel, combustible de aviación Jet A-1 y gasolina regular.

Abstract In this research it was studied the effect of the type of catalyst, the reaction temperature and the catalyst/ paraffins weight ratio in the transformation of paraffins waste obtained from the pyrolysis of plastics by catalytic cracking. It was chosen the Zeolite Y and Zeolite ZSM-5 as catalysts, the catalyst/paraffin weight ratios of 0.4:1 and 0.20:1 and the reaction temperatures of 400°C and 440°C. The catalytic cracking reaction of the paraffins was carried out in a fixed bed reactor. By the statistical analysis it was determined that the type of catalyst has the most outstanding effect, thus with the Zeolite ZSM-5 an average yield of 27.43% was reached. In contrast, with the Zeolite Y was obtained a 13.10%. In addition, it was found that the yield increased by 1.2% when a temperature of 400 ° C was used compared to 440°C. The catalyst/paraffin weight ratio does not significantly affect the yield. According to the analyzes performed by gas chromatography to the liquid reaction products, it would be expected that through this process products like diesel, Jet A-1 aviation fuel and gasoline could be obtained.

Removing Phosphate From Aquatic Environments Utilizing Fe-Co/Chitosan Modified Nanoparticles

Abstract: Chitosan modified iron-cobalt nanoparticles (CMNPs) were used for phosphate adsorption in synthetic wastewater and river water from the Jordan river in Tunja, Boyacá, Colombia. Phosphate adsorption by CMNPs reached 52.7% in synthetic wastewater and 58.7% in water taken from the Jordan river. This indicates that the CMNPs ability to adsorb phosphates is independent of other components within river water. Additionally, adsorption measurements were taken using the average pH, temperature, and phosphate concentration of the river water in order to ensure results comparable to those of (Kim 2017). A maximum adsorption rate of 0.138 mg of phosphate per gram of adsorbent was found with the majority of adsorption taking place within the first 15 minutes of contact with the adsorbent. The adsorption of phosphates using CMNPs presents an effective and environmentally friendly solution to reducing phosphates in aquatic ecosystems without altering the characteristics of river water.

Synthesis and structural characterization of the PR_3-XEU_XBA₅CU₈O₁₈system

Resumen Esta investigación describe la síntesis y caracterización del sistema Pr3XEuXBa5Cu8O18-5 con niveles de modificación (x=0, 0.5, 1, 1.5, 2 y 2.5), mediante el método de síntesis de reacción de estado sólido. Se utilizaron óxidos precursores de Pr6Ou, Eu2O3, BaO y CuO con purezas del (99.999 %). Se manejaron temperaturas de calcinación a 850 °C, sinterización a 900°C y oxigenación a 910 °C. La caracterización estructural se determinó por difracción de rayos X (DRX). Se hizo análisis estructural con refinamiento Rietveld en donde se evidencia la coexistencia de dos fases TR358 y TR123, se obtienen los parámetros de red y se logra una estructura cristalina tipo perovskita-ortorrómbica con grupo espacial Pmmm (47). Se concluyó que el aumento del nivel de modificación X con Eu en el sistema Pr3XEuXBa5Cu8O18-5 tiene gran incidencia en la composición porcentual de las fases y en los parámetros estructurales. El aumento o la disminución del valor de los parámetros de red en la estructura 358 y 123 se ven afectada por la mezcla de estados de oxidación del Pr con los de Eu, originando el cambio del tamaño de la celda.

Abstract This research describes the synthesis and characterization of the Pr3XEuXBa5Cu8O18-5 system with modification levels (x = 0, 0.5, 1, 1.5, 2 and 2.5). The synthesis process was achieved by solid state reaction (SSR). Precursor oxides of Pr6O11, Eu2O3, BaO and CuO were used with purities up to 99.999%. Calcination temperatures were handled at 850 ° C, sintering at 900 ° C and oxygenation at 910 ° C. The structural characterization was determined by X-ray diffraction (XRD). A structural analysis was carried out with Rietveld refinement, where the coexistence of two phases TR358 and TR123 was evidenced. The net parameters were obtained and a perovskite-orthorhombic crystal structure with spatial group Pmmm (47) was achieved. It was concluded that the increase of the X modification level with Eu in the Pr3-XEuXBa5Cu8O18-d system has a large impact on the percentage composition of the phases and structural parameters. The increase or decrease of the value of the net parameters in structure 358 and 123 is affected by the mixture of oxidation states of Pr with those of Eu, causing the cell size to change.

Preliminary phospholipase, hemolytic and bactericidal activity of the venom of the snake of cascabel del Tolima

Resumen En el departamento del Tolima no hay estudios que permitan precisar con certeza la magnitud del accidente ofídico causado por Crotalus durissus, existiendo la necesidad de generar información sobre el perfil proteico, como forma de aproximación a la compresión de algunas actividades biológicas relacionadas con la toxicidad del veneno, así como su potencial biotecnológico. En este trabajo se analizó el perfil electroforético por SDS-PAGE del veneno crudo extraído de individuos colectados en el municipio de Natagaima (Tolima) y la asociación con actividades fosfolipasa, hemolítica directa e indirecta y bactericida sobre Escherichia coli, Staphylococcus aureus y Pseudomona aeuroginosa. El veneno crudo presentó bandas de peso molecular 26.6 kDa., 17, 14.2, 6.5, 3.5 y 1.06 kDa., correspondientes con otros reportes previos del veneno para la especie. Se presentaron niveles considerables de actividades hemolítica (200 μg) y fosfolipasa (1.25 UA/mg. ± 0.88) dependientes de Calcio, y el efecto bactericida del veneno crudo fue diferencial sobre los microorganismos evaluados, presentando actividad moderada sobre Escherichia coli. Los resultados constituyen datos valiosos que confieren un acercamiento hacia el conocimiento del potencial tóxico del veneno de Crotalus durissus (cascabel) de la zona de Natagaima-Tolima, así como de la capacidad bactericida y posibles aplicaciones futuras en campos de investigación relacionados con la búsqueda de nuevos agentes antimicrobianos.

Abstract In the department of Tolima, there are no studies that allow us to determine with certainty the magnitude of the ophidian accident caused by Crotalus durissus, and there is a need to generate information on the protein profile, as a way of approaching the compression of some biological activities related to the toxicity of the venom, as well as its biotechnological potential. In this work, the SDS-PAGE electrophoretic profile of the crude venom extracted from individuals collected in the municipality of Natagaima (Tolima) and the association with phospholipase, direct and indirect hemolytic and bactericidal activities on Escherichia coli, Staphylococcus aureus and Pseudomonas aeuroginosa were analysed. The crude venom presented bands of molecular weight 26.6 kDa., 17, 14.2, 6.5, 3.5 and 1.06 kDa., corresponding to other previous reports of the venom for the specie. Considerable levels of calcium-dependent-hemolytic (200 μg) and phospholipase (1.25 AU/mg. ± 0.88) activities were presented, and the bactericidal effect of the crude venom was differential on the microorganisms evaluated, showing moderate activity on Escherichia coli. The results constitute valuable data that confer an approach towards the knowledge of the toxic potential of the venom of Crotalus durissus (rattlesnake) from the Natagaima-Tolima area, as well as the bactericidal capacity and possible future applications in research fields related to the search for new antimicrobial agents.