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Sancti Spíritus, Cuba

de Lima Vasconcelos R.,Sao Paulo State University | de Mello Prado R.,Sao Paulo State University | Reyes Hernandez A.,University Sancti Spiritus | Caione G.,Sao Paulo State University
Idesia | Year: 2014

The indirect measurement of chlorophyll is a diagnostic method of nitrogen in plants and its accuracy can be influenced by hour at which the reading is taken, the position of the leaflets in the plant and the portion where it is done on the leaflet reading. The objective was to evaluate the effect of hour reading, the position of the terminal leaflet on the leaf and the portion of the leaflet in the indirect of estimation of chlorophyll content index (CCI) with the use of chlorophyll meter. The experiment was performed with the cultivation of potato (S. tuberosum L.), Agate variety in the county of Ituverava São Paulo state, Brazil and consisted of 27 treatments in a factorial scheme 3 x 3 x 3 with four replications of 16 plant each, with a random distribution. The treatments were: three assessment times (08:00 am, 12:00 pm and 4:00 p.m.), three positions of leaflets on leafs (third, fourth and fifth) and three portions of the leaflet (basal, middle and distal). The evaluation of the CCI in the leaves of potato plants should be done in the leaflets of the third and fourth branch from top to bottom, regardless of the portion used leaflets, the 8:00 a.m. hours and 60 days after planting the crop. Indirect quantification of chlorophyll is a reliable tool and with potential to guide management of nitrogen fertilizer for crop. © 2014, Universidad de Tarapaca. All rights reserved. Source

Jimenez J.,University Sancti Spiritus | Cisneros-Ortiz M.E.,National Autonomous University of Mexico | Guardia-Puebla Y.,University of Granma | Morgan-Sagastume J.M.,National Autonomous University of Mexico | Noyola A..,National Autonomous University of Mexico
Water Science and Technology | Year: 2014

The anaerobic co-digestion of three wastes (manure, rice straw and clay residue, an inorganic additive) at different concentration levels and their interactive effects on methanogenic activity were investigated in this work at thermophilic conditions in order to enhance hydrolytic activity and methane production. A central composite design and the response surface methodology were applied for the optimization of specific methanogenic activity (SMA) by assessing their interaction effects with a reduced number of experiments. The results showed a significant interaction among the wastes on the SMA and confirmed that co-digestion enhances methane production. Rice straw apparently did not supply a significant amount of substrate to make a difference in SMA or methane yield. On the other hand, clay residue had a positive effect as an inorganic additive for stimulating the anaerobic process, based on its mineral content and its adsorbent properties for ammonia. Finally, the optimal conditions for achieving a thermophilic SMA value close to 1.4 g CH 4-COD/g VSS · d-1 were 20.3 gVSS/L of manure, 9.8 gVSS/L of rice straw and 3.3 gTSS/L of clay. © IWA Publishing 2014. Source

Jimenez J.,University Sancti Spiritus | Guardia-Puebla Y.,University of Granma | Cisneros-Ortiz M.E.,National Autonomous University of Mexico | Morgan-Sagastume J.M.,National Autonomous University of Mexico | And 2 more authors.
Chemical Engineering Journal | Year: 2015

The effect of pig manure, rice straw and clay residue concentrations, as well as their interactive effects on specific methanogenic activity (SMA) at mesophilic and thermophilic conditions were investigated in this work. A central composite design and the response surface methodology (RSM) were applied for designing the anaerobic co-digestion experiments, in order to optimize conditions to enhance methane production. The results showed a significant interaction among the substrates and an enhancement of the methane production and SMA response caused by the three components. The clay residues had a positive effect to reduce the inhibition of SMA caused by high concentration of pig manure due to the ammonia nitrogen adsorbent properties of clay demonstrated in this study by the Freundlich isotherm analysis. Thus, it was corroborated the positive effect of clay as inorganic additive for stimulating pig manure anaerobic digestion. The optimum condition for mesophilic anaerobic co-digestion of pig manure, rice straw and clay mixture was obtained for SMA values of 1.31 and 1.38gCH4-CODgVSS-1d-1 at mesophilic and thermophilic conditions, respectively. The optimization of the SMA using RSM made possible to identify the substrate interaction effects in a concentration range with a reduced number of experiments. Besides, the model validation proved to be useful for defining optimal combination of wastes considering their anaerobic co-digestion. SMA was also a good response variable for that purpose. © 2014 Elsevier B.V. Source

Gomez J.A.M.,University Sancti Spiritus
Revista Cubana de Salud Publica | Year: 2010

This article addressed why bioethics, which is ethics for life, has paid much more attention to the right of choosing the way of dying than to the right to life. This has a lot to do with the predominant Anglo-Saxon-type principled methodological and philosophical approach in the contemporary bioethical discourse that is also analyzed. It was suggested that this approach be supplemented with the principle of solidarity, all of which will encourage paying preferential attention to the right to life as fundamental and worrying. Source

Moda L.R.,Sao Paulo State University | Prado R.M.,Sao Paulo State University | Puente R.J.A.,University Sancti Spiritus | Flores R.A.,Federal University of Goais | And 2 more authors.
Australian Journal of Crop Science | Year: 2015

Many pasture areas have Al toxicity, P deficiency and low pH as limiting factors; thus, slag from steel mill can improve Tanzania grass phosphate nutrition by the beneficial effects of the interaction of Si and P. The objectives of this work were to evaluate the "availability" of P and Si in the soil, growth, P and Si accumulation and dry matter production in Tanzania grass plants. The experiment was carried out in a green house in a low-P soil amended with slag and lime and fertilized with P during three cutting seasons at Jaboticabal - São Paulo, Brazil. The experimental design was a randomized block arranged in a 2×5 factorial with three replicates. Treatments consisted of lime and steel mill slag applications. The other sources of variation were five rates of P [0, 100, 200, 300 and 600 mg dm-3 pot-1 as triple superphosphate (45% of P2O5 soluble in citric acid at 2%)]. The experimental units were 3 dm3 pots. There were increases in the variables plant growth and forage production with increases in available P, suggesting the use of slag as a soil amendment. Slag as soil corrective improved soil chemical attributes by pH correction and by increases in the base saturation index, reflecting in yield gains and in P and Si accumulation in the forage Panicum maximum. However, it did not increase the available Si in the soil, due to the low rates supplied, and did not differ from the traditional source regarding the availability of P in the soil. Source

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