72 research outputs found
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Brookes equation: The basis for a qualitative characterization of information behaviours
Brookes equation, which has hitherto been regarded as a kind of non-mathematical shorthand description of information use, is extended so as to show the qualitative pattern of information access. Information inputs are represented by a simple power law, and changes in knowledge structure by possible changes to a simple mental map. The resulting pattern shows seven forms of information input and three forms of change in knowledge structure, giving 21 categories overall. These have the potential for use as an explanatory tool and taxonomy for studying and summarizing information behaviour, and offer the possibility of being developed into more sophisticated and quantitative treatments
Reclamation status of a degraded pasture based on soil health indicators
Pasture degradation is a concern, especially in susceptible sandy soils for which strategies to recover them must be developed. Microbiological and biochemical soil health indicators are useful in the guindace of soil management practices and sustainable soil use. We assessed the success of threePanicum maximum Jacq. cultivars in the reclamation of a pasture in a sandy Typic Acrudox in the northwest of the state of Paraná, Brazil, based on soil health indicators. On a formerly degraded pasture withUrochloa brizantha (Hochst. ex A. Rich.) R.D. Webster, a trial with threeP. maximum (cv. Massai, Tanzânia, or Mombaça) was conducted. Lime and phosphate were applied at set-up, and mineral N and K as topdressing. A remnant of degraded pasture adjacent to the trial was used as control. Twenty-three chemical, physical, microbiological and biochemical attributes were assessed for the 0-10 cm topsoil. The procedures for reclamation improved most of the indicators of soil health in relation to the degraded pasture, such as soil P, mineral N, microbial biomass C, ammonification rate, dehydrogenase activity and acid phosphatase. CO2 evolution decreased, whereas microbial biomass C increased in the pasture under reclamation, resulting in a lower metabolic quotient (qCO2) that points to a decrease in metabolic stress of the microbial community. The reclamation of the pasture withP. maximum, especially cv. Mombaça, were evidenced by improvements in the microbiological and biochemical soil health indicators, showing a recovery of processes related to C, N and P cycling in the soil
Numerical Methods of Bibliographic Analysis
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