Fraccionamiento químico de la materia orgánica en tres suelos de la Colonia Tovar - Venezuela

This research was conducted on soils of small farmers in the Colonia Tovar - Venezuela, with an approximate height of 2000 m over the sea level, characterized by its template mountain weather. The sampling was done in the first 20 cm depth along 50 m transects, in three locations with different uses: forest, growing crops of strawberry and peach. All samples were processed for organic matter chemical fractionation. Fulvic acids, humic acids and no-humic substances by the Schnitzer and Schuppli method; total organic carbon (TOC) and organic carbon in each fraction by the Walkley and Black wet oxidation method modified for Heanes. Based on these results we determined the indices of humification. Randomized complete block with five repetitions design was used, the information were analyzed with Statistic 8,0 statistical package. In all parameters evaluated, highly significant differences were obtained. The forest remains higher in all cases: 32,3; 9,7; 10,9; 53,0 and 61,2 g.kg-1 of carbon for CAH, CAF, CSNH, Cext y COT respectively. According to the indexes, it was noted that the forest has a more stable and complex organic matter, and has a higher degree of humification (79%). Was concluded that the crop decrease the organic carbon content in all fractions of organic matter in these soils, as well as its degree of polymerizationEsta investigación se realizó en suelos de pequeños productores de la Colonia Tovar - Venezuela, a una altura aproximada de 2000 m.s.n.m, clima templado de montaña. El muestreo se hizo en los primeros 20 cm de profundidad en transectas de 50 m en tres localidades con distinto uso: bosque, cultivos de fresa y cultivo de durazno. El fraccionamiento químico de la materia orgánica: ácidos fúlvicos (CAF), ácidos húmicos (CAH) y sustancias no húmicas (CSNH), se hizo por el método Schinitzer y Schuppli y el carbono orgánico total (COT) y carbono orgánico de cada fracción por el método de oxidación en húmedo de Walkley y Black modificado por Heanes. Con base en estos resultados se determinaron los índices de humificación. Se utilizó un diseño completamente aleatarizado con cinco repeticiones, para lo cual se utilizó el paquete estadístico Statistic 8,0. Se obtuvieron diferencias altamente significativas en todos los parámetros evaluados, siendo el bosque quien se mantiene por encima en todos los casos: 32,3; 9,7; 10,9; 53,0 y 61,2 g.kg-1 de carbono para CAH, CAF, CSNH, Cext y COT respectivamente. De acuerdo con los índices, se pudo notar que el bosque posee una materia orgánica más estable, compleja y con un mayor grado de humificación (79%). Se concluyo que los cultivos disminuyen el contenido de carbono orgánico en todas las fracciones de la materia orgánica de estos suelos, al igual que su grado de polimerización

Effects of organic acid salts on ruminal biogas production and fermentation kinetics of total mixed rations with different maize silage to concentrate ratios

Methane is a major greenhouse gas (GHG) produced during the normal digestive process in ruminant animals (Blaxter and Clapperton, 1965) with a global warming potential, 25-fold that of carbon dioxide (IPCC, 2007). In addition to environmental implications, ruminant methanogenesis represents a loss of 2e12% of the gross energy intake (Johnson and Johnson, 1995; Soltanali et al., 2015) with a greater environmental impact from the confinement system compared with pasture-based system (O'Brien et al., 2012). A cow can produce 250 to 500 L of methane (CH4) per day depending on the quantity and quality of the feed which affects rate of digestion and rate of passage in the fermentation process (Johnson and Johnson, 1995). Furthermore, cattle consuming high fibre diets typically lose about 6% of gross dietary energy as methane (CH4), whereas those on high concentrate rations generally lose about 3% of dietary gross energy as CH4 (Mc Geough et al., 2012). According to the Food and Agriculture Organization of the United Nations, the livestock sector is responsible for about 18% of total global anthropogenic GHG emissionsRuminants are one of the major generators of methane, a greenhouse gas (GHG) with a global warming potential, 25-fold that of carbon dioxide. Methane production by ruminants also reduces the gross feed energy intake utilization by about 2e12%. The present study aimed to test the effects of different levels of a ruminal fermentation modulator (RFM) on in vitro ruminal fermentation and GHG production of five total mixed rations (TMR) with different silage (S) to-concentrate (C) ratios (0S:100C, 25S:75C, 50S:50C, 75S:25C, and 100S:0C). The RFM contained mainly calcium propionate and malate, and monopropylene glycol. The rumen inoculum was collected from a Brown Swiss cow fed a TMR of concentrate and alfalfa hay (1:1 dry matter (DM)) ad libitum. Gas production (GP) measurements were recorded up to 72 h of incubation. There were interactions (P 0.05) on methane production. The DM digestibility increased (linear effect; P ¼ 0.003) as silage level increased. Overall, increasing silage in the TMR lowered the asymptotic GP and DM digestibility. The asymptotic GP was higher with the addition of the RFM without any effect on fermentation kinetics. These results suggest that the RFM can be used as an environmental cleaner product in animal farming due to its ability to improve ruminal fermentation of feedstuffs and to reduce methane emission

Design and Development of a Hand Exoskeleton Robot for Active and Passive Rehabilitation

The present work, which describes the mechatronic design and development of a novel rehabilitation robotic exoskeleton hand, aims to present a solution for neuromusculoskeletal rehabilitation. It presents a full range of motion for all hand phalanges and was specifically designed to carry out position and force-position control for passive and active rehabilitation routines. System integration and preliminary clinical tests are also presented

Effectiveness of xylanase and Saccharomyces cerevisiae as feed additives on gas emissions from agricultural calf farms

Worldwide, agricultural farming systems, such as livestock production, face the increasing challenge of maintaining future global demand for meat and dairy products because of an expected increase in population (Wiedemann et al., 2017). The Food and Agriculture Organization (FAO, 2006) expects that an increase in purchasing power for food from animal sources raises the yearly demand to 465 and 1.043 million t for meat and milk products. Besides, the FAO estimates the growth of global population to reach 9.6 billion by the y 2050 (FAO, 2016), with a doubled purchasing power for meat and dairy products. To meet this rise in demand, agricultural systems need to devise a means to adapt to the probability of dangerous climate change and become more resilient, productive and sustainable (FAO, 2016)The aim of the present study was to evaluate the potential of supplementing calves’ diets with exogenous enzymes (xylanase; XYL) and yeast (Saccharomyces cerevisiae [SC]) on the sustainable control of methane (CH4) and carbon dioxide (CO2) productions in agricultural calves farming. Three different levels of supplemented diets of XYL (0, 3 and 6 mg/g of dry matter (DM)), SC (0, 2 and 4 mg/g of DM) and mixture of XYL and SC (0, 2 mL XYL þ 2 mg SC, 6 mL XYL þ 4 mg SC/g of DM) were tested. Asymptotic gas production (GP) consistently decreased by each of the additives with the lowest value at the high dose of XYL þ SC mixture (P < 0.05) compared with the control and the low dose of XYL þ SC mixture. Methane production was reduced by additives inclusion (P < 0.05) when compared with the control treatment with no additive. Xylanase þ SC at all doses increased CO2 production (P < 0.05) whereas the high dose had the most statistically significant (P < 0.05) reduction in GP and CH4 production compared with control, XYL and SC additives at different doses. Interaction between additive and rumen liquor was observed for rate of GP (P ¼ 0.027) and initial delay before GP (P < 0.001). Inclusion of XYL, SC, and XYL þ SC mixture had less asymptotic GP while XYL þ SC mixture had the lowest initial delay (39%) before GP began. The XYL þ SC had the lowest rate of CH4 production (9%) and highest asymptotic CO2 production (81%). The findings of this study indicate that inclusion of XYL or SC additives can improve rumen fermentation and reduce greenhouse gases production. The study also established that the mixture of XYL and SC is more efficient in reducing gas and CH4 emissions for cleaner environmental production conditions in calf farming

Virtual Seminar: an innovative educational experience

INTRODUCTION: it is of special importance that teachers can easily transmit knowledge, using didactical tools such as Cmaptools, Slideshare, YouTube, among others. Because of that, teaching methods nowadays are going through a revolution that implies technological development and the arrival of new generations. OBJECTIVE: describe the experience of developing a virtual education strategy in our institution to improve the teaching and learning process and facilitate interaction with students. METHODOLOGY: the students must do a bibliography search in databases (PubMed, Science Direct, and Embase) choosing one recent (published within the previous 3 months) original article in English. The article must involve the use of molecular techniques that include some sort of electrophoresis, then, get a tutoring session with the main teacher of the course, after that, the student must design a PowerPoint slideshow of a maximum of 15 slides. Finally, must record a 10-minute-long video of the presentation, the video must be uploaded to the YouTube website. RESULTS: a greater comprehension of the seminar presentation dynamic was observed in comparison to the previous methodology, which did not include the virtual component. CONCLUSIONS: the implementation of new innovative methodologies in education allows students to develop a broader learning process, besides improving their scientific understanding; they improve their knowledge on technological tools implemented in education.

High-pressure theoretical and experimental study of HgWO4

This is an Author's Accepted Manuscript of an article published in Lopez-Solano, J.; Rodriguez-Hernandez, P.; Muñoz, A.; Santamaria-Perez, D. et al.(2011). High-pressure theoretical and experimental study of HgWO4. High Pressure Research. 31(1):58-63. doi:10.1080/08957959.2010.521735HgWO 4 at ambient pressure is characterized using a combination of ab initio calculations, X-ray diffraction and Raman scattering measurements. The effect of low pressure and temperature on the structural stability is analysed. Extending our ab initio study to the range of higher pressures, a sequence of stable phases up to 30GPa is proposed. © 2011 Taylor & Francis.We thank J.M. Menendez for his help in the use of the GIBBS code. This work has been supported by the Spanish MEC under Projects MAT2007-65990-C03-01/03, MAT2010-21270-C04-03/04 and CSD-2007-00045 and by the "Vicerrectorado de Innovacion y Desarrollo de la UPV" (PAID-05-2009 through project UPV2010-0096). We gratefully acknowledge computational time provided by the "Red Espanola de Supercomputacion" at the supercomputer "Atlante". S. R. acknowledges financial support from the "Vicerrectorado de Investigacion de la UPV" through grant PAID-02-09-3085.Lopez-Solano, J.; Rodriguez-Hernandez, P.; Muñoz, A.; Santamaria-Perez, D.; Manjón Herrera, FJ.; Ray, S.; Gomis Hilario, O.... (2011). High-pressure theoretical and experimental study of HgWO4. High Pressure Research. 31(1):58-63. https://doi.org/10.1080/08957959.2010.521735S5863311Manjón, F. J., & Errandonea, D. (2009). Pressure-induced structural phase transitions in materials and earth sciences. physica status solidi (b), 246(1), 9-31. doi:10.1002/pssb.200844238Errandonea, D., Manjón, F. J., Garro, N., Rodríguez-Hernández, P., Radescu, S., Mujica, A., … Tu, C. Y. (2008). Combined Raman scattering andab initioinvestigation of pressure-induced structural phase transitions in the scintillatorZnWO4. Physical Review B, 78(5). doi:10.1103/physrevb.78.054116Ruiz-Fuertes, J., López-Moreno, S., Errandonea, D., Pellicer-Porres, J., Lacomba-Perales, R., Segura, A., … González, J. (2010). High-pressure phase transitions and compressibility of wolframite-type tungstates. Journal of Applied Physics, 107(8), 083506. doi:10.1063/1.3380848Lacomba-Perales, R., Errandonea, D., Martinez-Garcia, D., Rodríguez-Hernández, P., Radescu, S., Mujica, A., … Polian, A. (2009). Phase transitions in wolframite-typeCdWO4at high pressure studied by Raman spectroscopy and density-functional theory. Physical Review B, 79(9). doi:10.1103/physrevb.79.094105Manjón, F. J., López-Solano, J., Ray, S., Gomis, O., Santamaría-Pérez, D., Mollar, M., … Muñoz, A. (2010). High-pressure structural and lattice dynamical study ofHgWO4. Physical Review B, 82(3). doi:10.1103/physrevb.82.035212Kresse, G., & Hafner, J. (1993). Ab initiomolecular dynamics for liquid metals. Physical Review B, 47(1), 558-561. doi:10.1103/physrevb.47.558Kresse, G., & Furthmüller, J. (1996). Efficient iterative schemes forab initiototal-energy calculations using a plane-wave basis set. Physical Review B, 54(16), 11169-11186. doi:10.1103/physrevb.54.11169Blöchl, P. E. (1994). Projector augmented-wave method. Physical Review B, 50(24), 17953-17979. doi:10.1103/physrevb.50.17953Perdew, J. P., Ruzsinszky, A., Csonka, G. I., Vydrov, O. A., Scuseria, G. E., Constantin, L. A., … Burke, K. (2008). Restoring the Density-Gradient Expansion for Exchange in Solids and Surfaces. Physical Review Letters, 100(13). doi:10.1103/physrevlett.100.136406Monkhorst, H. J., & Pack, J. D. (1976). Special points for Brillouin-zone integrations. Physical Review B, 13(12), 5188-5192. doi:10.1103/physrevb.13.5188Blanco, M. A., Francisco, E., & Luaña, V. (2004). GIBBS: isothermal-isobaric thermodynamics of solids from energy curves using a quasi-harmonic Debye model. Computer Physics Communications, 158(1), 57-72. doi:10.1016/j.comphy.2003.12.001Kresse, G., Furthmüller, J., & Hafner, J. (1995). Ab initioForce Constant Approach to Phonon Dispersion Relations of Diamond and Graphite. Europhysics Letters (EPL), 32(9), 729-734. doi:10.1209/0295-5075/32/9/005Wahl, R., Vogtenhuber, D., & Kresse, G. (2008). SrTiO3andBaTiO3revisited using the projector augmented wave method: Performance of hybrid and semilocal functionals. Physical Review B, 78(10). doi:10.1103/physrevb.78.104116Jeitschko, W., & Sleight, A. W. (1973). The crystal structure of HgMoO4 and related compounds. Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry, 29(4), 869-875. doi:10.1107/s056774087300347

The causal effect of obesity on prediabetes and insulin resistance reveals the important role of adipose tissue in insulin resistance

Reverse causality has made it difficult to establish the causal directions between obesity and prediabetes and obesity and insulin resistance. To disentangle whether obesity causally drives prediabetes and insulin resistance already in non-diabetic individuals, we utilized the UK Biobank and METSIM cohort to perform a Mendelian randomization (MR) analyses in the non-diabetic individuals. Our results suggest that both prediabetes and systemic insulin resistance are caused by obesity (p = 1.2x10(-3)and p = 3.1x10(-24)). As obesity reflects the amount of body fat, we next studied how adipose tissue affects insulin resistance. We performed both bulk RNA-sequencing and single nucleus RNA sequencing on frozen human subcutaneous adipose biopsies to assess adipose cell-type heterogeneity and mitochondrial (MT) gene expression in insulin resistance. We discovered that the adipose MT gene expression and body fat percent are both independently associated with insulin resistance (p Author summary Obesity is a global health epidemic predisposing to type 2 diabetes (T2D) and other cardiometabolic disorders. Previous studies have shown that obesity has a causal effect on T2D; however, it remains unknown whether obesity causes prediabetes and insulin resistance already in non-diabetic individuals. By utilizing almost half a million individuals from the UK Biobank and the Finnish METSIM cohort, we identified a significant causal effect of obesity on prediabetes and insulin resistance among the non-diabetic individuals. Next, we investigated the role of subcutaneous adipose tissue in these obesogenic effects. We discovered that the adipose mitochondrial gene expression and body fat percent are independently associated with insulin resistance after adjusting for the tissue heterogeneity. For the latter, we estimated the adipose cell type proportions by utilizing single-nucleus RNA sequencing of frozen adipose tissue biopsies. Moreover, we established a prediction model to estimate insulin resistance using body fat percent and adipose RNA-sequencing data, which enlightens the importance of adipose tissue in insulin resistance and provides a helpful tool to impute the insulin resistance for existing adipose RNA-sequencing cohorts. Overall, we discover the potential causal effect of obesity on prediabetes and insulin resistance and the key role of adipose tissue in insulin resistance.Peer reviewe

Electrical analysis of piezoelectric ceramics of BaTiO3 doped with Cu and Ag

En esta investigación se estudia el efecto de la incorporación de partículas metálicas de cobre (Cu) <75μm y plata (Ag) <100nm, ambas de forma esférica de la marca ALDRICH, en la matriz del cerámico de titanito de bario (BaTiO3). La fabricación de estos materiales se realizó mediante la técnica de polvos; a partir de una mezcla, en un molino de giro planetario formando composiciones químicas en polvo como: BaTiO3 + 1% Cu, BaTiO3 + 3% Cu, BaTiO3 + 1% Ag, BaTiO3 + 3% Ag, BaTiO3 + 1% Cu & Ag, BaTiO3 + 3% Cu & Ag, cada muestra fue de 10 g. Los polvos fueron sometidos a un proceso de prensado para su conformación en muestras de forma cilíndricas y finalmente sinterizadas en un horno eléctrico a una temperatura de 1240 °C. A los materiales se le determinaron sus propiedades eléctricas, así como la determinación de la permitividad relativa del material, la capacitancia y la obtención de sus diagramas de magnitud - frecuencia eléctricas usando un generador de funciones. Los resultados obtenidos muestran que la incorporación de partículas de Cobre y Plata como un reforzamiento metálico en una base cerámica de BaTiO3 modifica las propiedades eléctricas - ferroeléctricas y dieléctricas

Evento cerebrovascular en pacientes post COVID-19

Objective: The present study aims to determine the association and the factors involved between had suffered a COVID-19 event with the development of a cerebrovascular event. Methods: This is an observational, case-control, analytical, retrospective study with a 1:2 relation. Applied in the population of the Emergency Department, Internal Medicine, and Family Medicine, of the General Hospital Zone with Family Medicine No. 32 of Minatitlan Veracruz. Results: A final sample of 111 cases and 222 controls was obtained. The average age is 58 years ±17.6. Of the total number of patients, 126 (37.8%) were men and 207 (62.2%) were women. 159 patients (47.74%) had a positive history of COVID-19. An Odds Ratio of 1.38 (95%; 0.876 – 2.186) was found. The age of the patients, the severity of the infection in its acute phase, the level of severity of the cerebrovascular event and the history of vaccination were statistically significant results. Conclusion: COVID-19 is associated as an independent factor with the development of a cerebrovascular event.Objetivo: El presente estudio pretende determinar la asociación y factores implicados entre haber padecido un evento de COVID-19 con el desarrollo de un evento cerebrovascular. Métodos: Es un estudio observacional, de casos y controles, analítico, retrospectivo, con relación 1:2. Aplicado en la población del servicio de Urgencias, Medicina interna y Medicina familiar, del Hospital General de Zona con Medicina Familiar N° 32 de Minatitlán Veracruz. Resultados: Se obtuvo una muestra final de 111 casos y 222 controles. El promedio de edad es de 58 años ±17.6. Del total de pacientes 126 (37.8%) son hombres y 207 (62.2%) son mujeres. 159 pacientes (47.74%) tuvieron antecedente positivo de COVID-19. Se encontró un Odds Ratio de 1.38 (95%; 0.876 – 2.186). La edad de los pacientes, la gravedad de la infección en su fase aguda, el nivel de gravedad del evento cerebrovascular y el antecedente de vacuna, fueron resultados estadísticamente significativos. Conclusión: El COVID-19 se encuentra asociado como factor independiente al desarrollo de evento cerebrovascular

Fibrinogen-to-Albumin Ratio and Blood Urea Nitrogen-to-Albumin Ratio in COVID-19 Patients: A Systematic Review and Meta-Analysis

Fibrinogen-to-albumin ratio (FAR) and blood urea nitrogen-to-albumin ratio (BAR) are inflammatory biomarkers that have been associated with clinical outcomes of multiple diseases. The objective of this study is to evaluate the association of these biomarkers with the severity and mortality of COVID-19 patients. A systematic search was performed in five databases. Observational studies that reported the association between FAR and BAR values with the severity and mortality of COVID-19 patients were included. Random-effects models were used for meta-analyses, and effects were expressed as Odds Ratio (OR) and their 95% confidence intervals (CI). Publication bias was assessed using the Begg test, while the quality assessment was assessed using the Newcastle Ottawa Scale. A total of 21 studies (n = 7949) were included. High FAR values were associated with a higher risk of severity (OR: 2.41; 95% CI 1.41–4.12; p < 0.001) and mortality (OR: 2.05; 95% CI 1.66–2.54; p < 0.001). High BAR values were associated with higher risk of mortality (OR: 4.63; 95% CI 2.11–10.15; p < 0.001). However, no statistically significant association was found between BAR values and the risk of severity (OR: 1.16; 95% CI 0.83–1.63; p = 0.38). High FAR and BAR values were associated with poor clinical outcomes.Revisión por pare