Structure and composition of bacterial and fungal community in soil under soybean monoculture in the Brazilian Cerrado

Soybean is the most important oilseed cultivated in the world and Brazil is the second major producer. Expansion of soybean cultivation has direct and indirect impacts on natural habitats of high conservation value, such as the Brazilian savannas (Cerrado). In addition to deforestation, land conversion includes the use of fertilizers and pesticides and can lead to changes in the soil microbial communities. This study evaluated the soil bacterial and fungal communities and the microbial biomass C in a native Cerrado and in a similar no-tillage soybean monoculture area using PCR-DGGE and sequencing of bands. Compared to the native area, microbial biomass C was lower in the soybean area and cluster analysis indicated that the structure of soil microbial communities differed. 16S and 18S rDNA dendrograms analysis did not show differences between row and inter-row samples, but microbial biomass C values were higher in inter-rows during soybean fructification and harvest. The study pointed to different responses and alterations in bacterial and fungal communities due to soil cover changes (fallow x growth period) and crop development. These changes might be related to differences in the pattern of root exudates affecting the soil microbial community. Among the bands chosen for sequencing there was a predominance of actinobacteria, y-proteobacteria and ascomycetous divisions. Even under no-tillage management methods, the soil microbial community was affected due to changes in the soil cover and crop development, hence warning of the impacts caused by changes in land use

Application Of Chemometric Tools For Automatic Classification And Profile Extraction Of Dna Samples In Forensic Tasks

In this paper a method for the automatic DNA spots classification and extraction of profiles associated in DNA polyacrilamide gel electrophoresis is presented and it integrates the use of image processing techniques and chemometrics tools. A software which implements this method was developed; for feature extraction a combination of a PCA analysis and a C4.5 decision tree were used. To obtain good results in the profile extraction only DNA spots are useful; therefore, it was necessary to solve a two-class classification problem among DNA spots and no-DNA spots. In order to perform the classification process with high velocity, effectiveness and robustness, comparative classification studies among support vector machine (SVM), K-NN and PLS-DA classifiers were made. The best results obtained with the SVM classifier demonstrated the advantages attributed to it in the literature as a two-class classifier. A Sequential Cluster Leader Algorithm and another one developed for the restoration of pattern missing spots were needed to conclude the profiles extraction step. The experimental results show that this method has a very effective computational behavior and effectiveness, and provide a very useful tool to decrease the time and increase the quality of the specialist responses. © 2007 Elsevier B.V. All rights reserved.5951-2 SPEC. ISS.4350Gill, P., Urquhart, A., Millican, E., Oldroyd, E., Watson, N., Sparkers, S., (1996) Adv. For. Haemogenet., pp. 235-242Lander, E.S., (1993) Science, 260, p. 1221Lewontin, C., Hartl, D., (1991) Science, 254, pp. 1745-1750Weber, J., May, P., (1989) Am. J. Hum. Genet., 44, pp. 388-396Kacmazmarek, B., Walczak, B., Jong, S., (2003) Anal. Chem., 75, pp. 3631-3636Gonzalez, R., Woods, R., (2004) Digital Image Processing using MATLAB. second ed., , Prentice Hall pp. 385-387Jackson, J.E., (1991) A User's Guide to Principal Components, , John Wiley & Sons, New YorkWold, S., Sjostrom, M., Chemometrics: Theory and Application (1977) ACS Symposium Series, 52, pp. 243-282. , Kowalski B.R. (Ed) Chapter 12Vapnik, V., Chervonenkis, A., (1974) Theory of Pattern Recogn, , Nauka, MoscowVapnik, V., (1995) The Nature of Statistical Learning Theory, , Springer VerlagScholkopf, C., Burges, J., Smola, A., (1999) Advances in Kernel methods, , MIT PressHartigan, J., (1975) Clustering Algorithm, , John Wiley and Sons, New YorkSilva, F., Talavera, I., González, I.R., Hernández, N., Palau, J., Santiesteban, M., (2005) LNCS, 3773, pp. 242-251Álvarez, A., Ruiz, J., Sanchiz, M., (2003) LNCS, 2905, pp. 512-520Witten, I.H., Frank, E., (2005) Data Mining Practical Machine Learning Tools and Techniques. second ed., , Morgan Kaufmann Publisher Part II The WEKA Machine Learning workbenc

Role of soil carbon in the landscape functioning of the Alto São Bartolomeu watershed in the Cerrado region, Brazil

El trabajo muestra los resultados del comportamiento térmico de una vivienda social construida masivamente por el Instituto Provincial de la Vivienda (IPV), monitoreada desde el 30 de abril hasta el 05 de junio de 2008. Se localiza en la periferia norte de la capital de Catamarca y su uso es residencial. Esta conformada por porch, cocina-comedor, dormitorios y baño que totalizan una superficie de 43.04 m2. El objetivo principal es conocer el comportamiento térmico en relación a parámetros de confort. En este sentido se monitorearon y analizaron tres periodos representativos: 1) 30/04/08 al 06/05/08, 2) 18 al 24/05/08 y 3) 30/05/08 al 05/06/08. Los resultados han demostrado que cuando las condiciones de las temperaturas exteriores son más rigurosas (altas o bajas) la respuesta del diseño de su envolvente es insuficiente para alcanzar los rangos de confort térmico establecidos y como consecuencia de ello demanda mayor cantidad de energía auxiliar para su acondicionamiento.This study shows the results of the thermal behavior of a house built by the Provincial Housing Institute examined since April 30th until June 5th in the year 2008. The house is placed to the North of the Capital city of Catamarca and it is used as dwelling. It includes a porch, dining room and kitchen, bedrooms and bathroom, all comprising a 43.04m2 covered surface. The main purpose of this work is to know the thermal behavior in ralation to comfort parameters. To this end, three representative periods were observed and analysed: 1) April 30th to May 6th, 2008; 2) May 18th to May 24th, 2008; and 3) May 30th to June 5th, 2008. The results have demonstrated that, when the external weather conditions are more severe (high or low), the answer of the enveloping design is insufficient to reach the established thermal comfort ranges; as a consequence, the design demands more auxiliary power for fitting out.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES