2,023 research outputs found
The Use of Industrial Waste for the Bioremediation of Water Used in Industrial Processes
Recently the interest in the remediation of liquid effluents from industries such as paint manufacturing, leather tanning, etc. has increased, because the quality of the water used in these processes is highly compromised and is generally discarded without any process of purification, causing an inadequate use of water and contributing to the hydric stress of the planet. Therefore, it is necessary to find alternatives for the remediation of water used in industrial processes; one of the methods that has been widely accepted given its high efficiency, low cost, and versatility compared to others is the bioadsorption using materials derived from various processes used for the elimination of metals such as Cr, Co, Cu, Ni, etc. from liquid effluents. Among the materials used for this purpose are rice husk, orange, and wheat as well as apatite (hydroxyapatite and brushite), derived from animal bones, which have shown good capacity (>90%) to adsorb metals from aqueous solutions. Through the characterization by DRX, FTIR, and SEM, of the brushite and studies in equilibrium and kinetics of adsorption, it has been demonstrated that this material has a good capacity to remove metals present in water
Fragility Curves for Thin-Walled Cold-Formed Steel Wall Frames Affected by Ground Settlements Due to Land Subsidence
Land subsidence phenomenon due to ground water withdrawal is a current problem in many places around the world, particularly in the shallows of Mexico. This causes ground differential settlements that affect structures, mainly dwellings and buildings based on reinforced concrete and masonry. Eventually, these structural materials do not exhibit an adequate performance beyond a certain level of angular distortion. This work presents the results about a study regarding the performance of thin-walled cold-formed steel wall frames with different sheathing systems affected by angular distortions simulating ground differential settlements due to land subsidence. The wall frames are composed by vertical (studs) and horizontal elements (tracks), with different sheathing systems: polystyrene, OSB, gypsum and calcium silicate. By means of experimental testing of wall frames subjected to monotonic lateral loads, the rotational stiffness was obtained for the wall frames with polystyrene. Likewise the rotational stiffness of the other wall frame systems was calculated based on the data provided by other author’s publications. On the other hand, by means of numerical simulation, all the wall frame systems were modeled in structural analysis software, calibrating them based on the rotational stiffness. Also, the moment-rotation curves were calculated for the studs and tracks based on the direct strength method. A non-linear static pull down analysis was performed producing several degrees of angular distortion simulating ground settlements for all the wall frames sheathing systems. With the data acquired fragility curves were calculated according three levels of damage for the wall frames with different sheathing system
Physical Education Classes as a Precursor to the Mediterranean Diet and the Practice of Physical Activity
Physical activity and a healthy, balanced diet are remaining unresolved issues among young people. According to the World Health Organization, young people do not get enough exercise during the week, and physical education classes are the best way to promote healthy habits. This study aims to analyze how the role of the teacher influences the frustration of psychological needs, coping strategies, motivation, and the adoption of healthy eating habits through the Mediterranean diet and the regular practice of physical activity. The study involved 1031 boys and 910 girls between the ages of 13 and 18. To explain the relationships between the different variables included in this study, a model of structural equations has been developed. The results showed that autonomy support negatively predicted the frustration of four psychological needs. The failure to meet four psychological needs negatively predicted resilience. Likewise, resilience positively predicted autonomous motivation, and this positively predicted the Mediterranean diet and the practice of physical activity. Thus, the results obtained in the present study are in line with those of various studies wherein physical education classes were seen to help consolidate healthy living habits
Soil macroinvertebrates community and its temporal variation in a well-drained savannah of the Venezuelan Llanos
Morales-Márquez, Jimmy A., Hernández-Hernández, Rosa M., Sánchez, Gloria K., Lozano, Zenaida, Castro, Ignacio, Bravo, Carlos, Ramírez, Elizabeth and Jiménez Ballesta, Raimundo: "Soil macroinvertebrates community and its temporal variation in a well-drained savannah of the Venezuelan Llanos" published at European Journal of Soil Biology 84.2 (2018): 19-26; DOI: http://doi.org/10.1016/j.ejsobi.2017.11.002In the well-drained savannahs of Venezuelan Llanos, intensive agricultural activities could be causing damage to the soil, with negative consequences for the ecosystem. In order to avoid this problem, some agroecological alternatives are needed. Consequently, it is necessary to know the biologic dimension in this ecosystem, and within this, the soil macroinvertebrate community. The purpose of this work was to characterize this community in the natural savannah: its structure and diversity, its time variation and its relationship with the physical-chemical properties of the soil. A total of 72 samples were taken in different season along a period of time of 1405 days. The results revealed that the soil macrofauna had an average density of 243.5 ± 183.6 ind·m −2 , distributed in 32 families of 11 orders, with a diversity of N 1 = 4.5 ± 2.8 families. Coleoptera, Hymenoptera and Isoptera was the most dominants orders. The density, richness and diversity of families showed a temporal variation (r ≥ −0.5; p < 0,05). Additionally, the structure of the soil macroinvertebrate community showed a vertical variation. The relationship with soil properties differed according families: Lampyridae, Aphodiidae and Formicidae had a positive correlation with soil macro-porosity (radius of the pores > 15 μm); Tenthredinidae and Tenebrionidae had a positive correlation with the micro-porosity (pores ≤ 15 μm). The community in general, correlated positively with soil porosity and negatively with bulk density. This suggests that these soil properties need to be considered when designing agroecological technics in this area.We want to express our gratitude to the "Fondo Nacional para la Ciencia Innovación y Tecnología del Ministerio del Poder Popular para la Educación Universitaria, Ciencia y Tecnología", of the Boliviarian Republic of Venezuela, for the financial support of the project “Manejo Agroecológico de Suelos de Sabanas Bien Drenadas con Unidades de Producción Cereal-Ganado”, Nº G-2002000398, of which this study is part
Alkaline pretreatment of Mexican pine residues for bioethanol production
The locally sourced residue samples of Pinus arizonica, Pinus cooperi, and Pinus durangensis from the state of Durango in Mexico were analyzed for optimal yield of ethanol production. The samples were mixed at an equal proportion using a particle size of 0.59 mm. Each individual mixture was pretreated with either NaOH or Ca (OH)2 (at 0.5, 1.0 and 1.5% w/v) for periods of 30, 60, and 90 min at 60, 90, and 120°C. The pretreated blending was subjected to enzymatic hydrolysis for 130 h at 80 rpm and 50°C with an enzymatic load of 25 filter paper units (FPU) and 50 IU β-glucosidase per gramme of cellulose to obtain a maximum yield of reducing sugars (RS) with NaOH subject at 120°C for 90 min. The results show that the hydrolysis yield depends on temperature and alkali concentration particularly (NaOH), which increased from 2.0 to 3.5% w/v. The best yield of glucose (41.33% w/w) was obtained using a pretreatment of 2.5% NaOH for 90 min, 120°C, and a hydrolysis residence time of 130 h. The removal of lignin and hemicellulose acetylation was observed to have influence on the enzymatic digestibility of cellulose. This process could theoretically produce a maximum yield of 90.19% of ethanol / substrate (glucose) and about 80 L of bioethanol per dry ton of woody biomass from pine residues.Keywords: Lignocellulosic biomass, alkaline pretreatment, enzymatic hydrolysis, fermentable sugars, fermentationAfrican Journal of Biotechnology Vol. 12(31), pp. 4956-496
VO2peak and Watt exercise testing: arm crank vs cycle ergometry
INTRODUCTION: Multiple sclerosis is a disease of the central nervous system that primarily affects the strength and functional capacity of the lower extremities. PURPOSE: The objectives of the present study were evaluate VO2peak and the power output (W) during a leg and an arm test performance in relapsing-remitting multiple sclerosis (MS) versus healthy people (HP). METHODS: Twelve women (age 45.8 ± 11.8 yr) with MS (EDSS 3.3 ± 1.8) and twelve women (age 45.6 ± 10.7 yr) HP were included in this study. They underwent two incremental exercise tests on an electromechanical braked arm crank ergometer and on an electromagnetic braked leg cycling ergometer separately. A computerized gas analysis system collected and analyzed gas exchange during the two kinds of testing. The statistical analysis was determined with the Wilcoxon test. RESULTS: First, VO2peak (21.5 ± 5.9 vs. 30.5 ± 4.8 ml·kg·min-1, p = 0.001) y W (84.5 ± 30.1 vs. 141.0 ± 13.7, Watt, p =0.0001) during cycle ergometer test were significantly lower in MS compared with HP. Similarly, the VO2peak in MS during arm crank was significantly lower (16.7 ± 5.4 vs. 23.4 ± 5.1 ml·kg·min-1, p = 0.023) compared with HP. However, the power generated by the arm was not different between the groups. CONCLUSION: The patients with MS during leg ergometer test showed a lower VO2peak. In the same sense, the patients with MS showed lower VO2peak in the test performed with the arms. Interestingly, the power generated with arms was similar in the two groups. These results indicate, that the patients with MS reflect a greater affectation to produce high loads of physical work with legs but not with arms. Further research is suggested where both the lower and upper extremities are involved to improve the processes of rehabilitation in MS
Análisis Comparativo Del Posicionamiento GNSS Utilizando Receptor De Bajo Costo U-Blox De Doble Frecuencia Para Aplicaciones Topógrafo-Geodésicas
Se evaluó y comparó estadísticamente el posicionamiento obtenido a través del receptor de bajo costo U-blox ZED-F9P de nueva generación con un receptor geodésico, realizando observaciones GNSS sobre un vértice geodésico mediante del método de Posicionamiento Puntual Preciso y relativo estático, con una distancia de 33 km a la estación de referencia. Esto, con la finalidad de probar la factibilidad de utilizar receptores de bajo costo de gama similares en trabajos topográficos-geodésicos. Para ello, se consideran cuatro escenarios; en el primer escenario, se aplicó la técnica relativo estático con el equipo de bajo costo, en el segundo escenario se procesó con un receptor geodésico en modo relativo estático; ambos mediante un software comercial. Para el tercer y cuarto escenario, se procesó modo Posicionamiento Puntual Preciso con el software RTKLIB. Los resultados muestran que para la técnica Posicionamiento Puntal Preciso la precisión lograda de 1 cm por el equipo de bajo costo es apta para realizar trabajos geodésicos. En el método relativo estático, la precisión lograda de 7 mm indica que es posible utilizar el equipo de bajo costo para trabajos topógrafos-geodésicos de alta precisión considerando una línea base ≤33 km, esto, según la normatividad del Instituto Nacional de Estadística y Geografía.
The new generation, low-cost U-blox ZED-F9P receiver was evaluated and statistically compared by GNSS observations on a geodesic monument, through both Precise Point Positioning and Static relative positioning techniques with a distance of 33 km from the references station. This was done with the purpose of checking the use feasibility of the low-cost receiver of similar gamma in topographic-geodesic works. To that end, four scenarios were considered: in the first scenario, the static relative positioning with the low-cost equipment was applied; in the second scenario, the static relative positioning with a geodetic receiver was applied. Both scenarios were processed with commercial software. The third and fourth scenarios were processed with Precise Point Positioning techniques through the RTKLIB software. The results show that Precise Point Positioning techniques get a precision of 1 cm through the use of low-cost equipment which is suitable to apply in geodetic works. In the static relative method, the precision obtained is 7 mm, indicating the possibility of using the low-cost equipment in both survey and geodetic high precision works, considering a line base ≤30 Km, according to the Instituto Nacional de Estadística y Geografía normative
Proyecto de 3 unidades de negocio de comida rápida mexicana
En el proyecto PAP para la competitividad Otoño 2022 se trabajó en el cierre del proyecto que inició en Otoño 2021 con una “dark kitchen” de comida casera empacada al vacío y que fue evolucionando hasta convertirse en una empresa con 3 líneas distintas de negocio.
Para este cierre de proyecto se planteó como objetivo, diseñar productos que faciliten la toma de decisiones estratégicas. Durante el proceso de consultoría se fue madurando de la mano con los empresarios, iniciando con análisis y productos genéricos hasta lograr diseñar herramientas, manuales y controles a la medida de las necesidades de los empresarios,
adecuados a su estilo de liderazgo, metodología para toma de decisiones y alineadas a las competencias que se definieron para desarrollar en ellos durante este proceso PAP.
Los productos entregados constan de:
• Una plantilla en Excel automatizada que provee la siguiente información: estado de resultados, mensual y anual, costos por unidad de negocio, y gastos por unidad de negocio.
• Un formato de control para asegurar la rentabilidad en las promociones aplicadas.
• Una herramienta de proyección de ventas que ayuda a anticipar si se cumplirá o no el objetivo y en caso de no lograrlo, qué nivel de promoción se debe realizar para cumplir con la meta definida.
• Tres manuales para el manejo de marca, redes sociales y legales.
Con la entrega de estos productos se logró concientizar a los empresarios en la importancia de la toma de decisiones basada en información, así como la interrelación entre todas las áreas, hoy en día la toma de decisiones se realiza de la siguiente manera: en un 90% basadas en información financieras y de mercado y 10% en intuición.
Con este resultado se logró el punto de equilibrio, aumentar las interacciones en redes sociales, incrementar la rentabilidad de negocio y generar una estructura para un crecimiento sólido.ITESO, A.C
INFLUENCIA DE UN GRUPO DE MEJORA EN LA IMPLEMENTACIÓN DEL LENGUAJE DE NANDA.
We want to show the importance of an improvement group for the normalization of health care. This can only be made based on the evidence. For this reason, we carry out two evaluations related to the knowledge and the use of the nursing language among the nursing professionals working in our health care centre.
The first evaluation was carried out in 2000 and the second one in 2003. The sample in the first evaluation was 50 and in the second it comprised 49 cases. A questionnaire was used (5 questions contained a guided answer).Demostrar la importancia de la presencia de un grupo de mejora en la normalización de los cuidados sólo puede hacerse a través de la evidencia, para ello hacemos dos evaluaciones relacionadas con el conocimiento y uso del lenguaje enfermero por los profesionales de nuestro centro
Monitoring Physiological Responses in Giant Toad (Rhinella marina) from Coatzacoalcos, Mexico: A Comparative Study after 8 Years
The objective of this chapter is to present the results of a monitoring study carried out with physiological responses (biomarkers) in Rhinella marina (giant toad) for two different years, inhabiting the low basin of Coatzacoalcos river, one of the most contaminated regions in Mexico. A decrease in delta aminolevulinic acid dehydratase (δ-ALAD) (considered inhibition) and in the condition factor (1.2–1.5 times) found in toads of the industrial zone compared with reference organisms, each year. As for the hematological parameters, the mean corpuscular hemoglobin concentrations (MCHC), in the amphibians of industrial zone of the first sampling year show a decrease, while for the second sampling year, show an increment of 1.5 times than organisms of reference site. These effects could be associated with exposure to pollutants such as heavy metals (mainly Pb), which have been registered in different studies. This study demonstrates the usefulness of giant toads as biomonitors of contaminated sites
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