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This work evaluates the community of soil nematodes in agricultural and livestock environments with different intensity of land use in the southeast of the province of Buenos Aires. Nematodes were extracted from sites with different intensity of land use: corn (2 consecutive years of conventional tillage [LC]), potato (1 year of LC), soybean (direct seeding), and pastures (with grazing animals). 44 genera of nematodes belonging to 5 trophic groups were identified. The most abundant genera were Helicotylenchus, Pratylenchus and Cruznema. Significant differences were found in the structure of the nematode community between land uses. The total abundance and by trophic groups was higher in soybeans and pasture. Furthermore, in relation to the composition of the community of free-living nematodes (bacteriophages, frugivores, omnivores and predators), the sites with corn and soybeans presented a higher proportion of fungivores, while the sites with potatoes and grass showed a higher proportion of bacteriophages. In relation to phytophagous nematodes, the community associated with sites with greater agricultural disturbance (corn and potatoes) presented a different and less diverse assembly than those associated with sites with less disturbance (soybean and pasture). The nematological indices showed that the successional dynamics of the nematode communities were affected due to land use practices. This was confirmed through the analysis of the faunal profile, the majority of food chains, regardless of the type of land use, were affected by agronomic practices showing mature food webs. This work constitutes the first report on the composition of soil nematode communities in agricultural and livestock production fields in southeastern Buenos Aires, and contributes to understanding the ecology of soil nematode communities impacted by different anthropogenic practices. [ABSTRACT FROM AUTHOR]

Copyright of Actualizaciones en Osteología is the property of Asociacion Argentina de Osteologia y Metabolismo Mineral and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Colombiana de Educación is the property of Universidad Pedaggica Nacional and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of International Journal of Political Philosophy / Las Torres de Lucca is the property of Revista Las Torres de Lucca. Facultad de Filosofia, Ciudad Universitaria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Espacios is the property of Talleres de Impresos Oma and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The production of vegetables on substrates has become a great alternative. Therefore, different substrates were evaluated in a greenhouse lettuce culture. A completely randomized block design (BCA) with three treatments was used as follows: T1: peat 30% coconut peat 70%, T2: peat 70% coconut peat 30% and T3: peat 50% Coconut peat 50%, for a total of 9 experimental units each consisting of 10 plants. Every 8 days, during 32 days, the height of the plant, fresh and dry mass of leaves and root, leaf area and every 2 days, the SPAD units and the stomatal conductivity (SC) were determined. There were significant differences in the SPAD units in time for day 11 ddt with a value of 20.7. The SC presented the highest values in T3 and T2 with values of 354.2 and 366.2 mol m-2 s-1, respectively. T1 presented the highest value of stomatal resistance (RE) with 7.5 m² s mol-1. The leaf area and height did not show significant differences. T2 at 15 days after transplant showed the highest values of fresh root mass (MFR), dry root mass (MSR) and fresh leaf mass (MFH) with 3.1 g, 0.106 g and 13.19 g respectively. In harvest, T3 showed 10% and 15% more production of MFH in lettuce than treatments T2 and T1, respectively. [ABSTRACT FROM AUTHOR]

Protein hydrolysates were prepared from viscera of red tilapia (Oreochromis spp.), an important fish species of great production in Colombia. Hydrolysis with three different enzymes (Alcalase, Flavourzyme and Neutrase) were evaluated to establish which of them deliver the highest degree of hydrolysis (DH) using the pH-stat method. On each enzyme a 22 factorial design was applied to evaluate the effect of temperature and pH on the DH. Maximum DH values of 10.9% for Alcalase and 3.9% for Flavourzyme and Neutrase were obtained. Subsequently, a response surface 32 analysis for the hydrolysis with Alcalase was performed. The results showed that the DH is maximized when working at pH= 9.5 and T= 53.45°C keeping constant the initial substrate concentration, enzyme concentration and reaction time. Finally the effect of substrate was evaluated varying protein concentration between 12.5 g/L, 21.25 g/L, 29.5 g/L and 37.5 g/L. Furthermore, the kinetic constants of Michaelis-Menten were evaluated. [ABSTRACT FROM AUTHOR]

Copyright of Revista Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Potentially nitrogen-fixing microaerobic and aerobic bacteria were isolated from several Colombian Amazon soils (forest, pastures and chagras) and two landscapes (floodable and non floodable areas). The abundance and distribution of bacteria were evaluated, as well as their relationship with soil physical and chemical characteristics. Landscape had a direct influence on the abundance of the microaerobic bacteria, with higher numbers in forest and pasture soils in non-floodable zones. The aerobic isolates (N=51) were grouped into 19 morphologies, with the highest numbers found in forest soil in floodable zones. A higher number of aerobic morphologies was shared among forest sites (Nonmetric Multidimensional Scaling and Analysis of Similarity p<0.05), and 40% of the distribution was explained by lime percentage and Al concentration. Rev. Biol. Trop. 57 (4): 915- 927. Epub 2009 December 01. [ABSTRACT FROM AUTHOR]

Copyright of Revista Umbral Científico is the property of Universidad Manuela Beltran and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)