Nonlinear Relativistic and Quantum Equations with a Common Type of Solution

Generalizations of the three main equations of quantum physics, namely, the Schr\"odinger, Klein-Gordon, and Dirac equations, are proposed. Nonlinear terms, characterized by exponents depending on an index $q$, are considered in such a way that the standard linear equations are recovered in the limit $q \rightarrow 1$. Interestingly, these equations present a common, soliton-like, travelling solution, which is written in terms of the $q$-exponential function that naturally emerges within nonextensive statistical mechanics. In all cases, the well-known Einstein energy-momentum relation is preserved for arbitrary values of $q$

Episodic nitrous oxide soil emissions in Brazilian savanna (cerrado) fire-scars

The seasonally burned cerrados of Brazil are the largest savanna-type ecosystem of South America and their contribution to the global atmospheric nitrous oxide (N20) budget is unknown. Four types of fire-scarred cerrado along a vegetation gradient from grassland to forest were investigated during the wet season of 1992/93. The effect of fire and subsequent water additions on epiodic emissions of N2O and the associated profile dynamic of soil/gas phase N2O concentrations were studied for several months. Additionally, the effect on episodic emissions of N2O of nitrate and glucose additions to a cerrado soil after fire and the associated profile dynamic of soil/gas phase N2O mixing ratios were determined. Finally, N2O episodic emissions in cerrado converted to corn, soybean, and pasture fields were investigated during one growing/wet season. Results showed N2O consumption/emission for the four fire-scared savanna ecosystems, for nitrogen and carbon fertilization, and for agriculture/pasture ranging from -0.3 to +0.7, 1.8 to 9.1, and 0.5 to 3.7 g N2O-N ha(exp -1) d(exp -1), respectively. During the wet season the cerrado biome does not appear to be a major source of N2O to the troposphere, even following fire events. However, the results of this study suggest that conversion of the cerrado to high input agriculture, with liming and fertilization, can increase N2O emissions more than ten fold

Thermostatistics of overdamped motion of interacting particles

We show through a nonlinear Fokker-Planck formalism, and confirm by molecular dynamics simulations, that the overdamped motion of interacting particles at T=0, where T is the temperature of a thermal bath connected to the system, can be directly associated with Tsallis thermostatistics. For sufficiently high values of T, the distribution of particles becomes Gaussian, so that the classical Boltzmann-Gibbs behavior is recovered. For intermediate temperatures of the thermal bath, the system displays a mixed behavior that follows a novel type of thermostatistics, where the entropy is given by a linear combination of Tsallis and Boltzmann-Gibbs entropies.Comment: 4 pages, 2 figure

Ability-based view in action: a software corporation study

This research investigates antecedents, developments and consequences of dynamic capabilities in an organization. It contributes by searching theoretical and empirical answers to the questions: (a) What are the antecedents which can provide an organization with dynamic and ordinary capabilities?; (b) How do these antecedents contribute to create capabilities in an organization?; (c) How do they affect an organization's competitive advantage?; (d) Can we assess and measure the antecedents and consequences to an organization? From a first (theoretical) perspective, this paper searches answers to the first, second and third questions by reviewing concepts of an ability-based view of organizations that involves the abilities of cognition, intelligence, autonomy, learning and knowledge management, and which contributes to explain the dynamic behavior of the firm in the pursuit of competitive advantage. From a second (empirical) perspective, this paper reinforces and delivers findings to the second, third and fourth questions by presenting a case study that evidences the ability-based view in action in a software corporation, where it contributes by investigating: (a) the development of organizational capabilities; (b) the effects of the new capabilities on the organization; and (c) the assessment and measurement of the abilities and consequences

Teste de desempenho individual de reprodutores da raça Morada Nova: resultados da prova em Morada Nova, CE; 18/02 a 04/06/2008.

bitstream/CNPC-2010/23054/1/doc91.pd

Optimization of a fructooligosaccharides purification method using activated charcoal

Fructooligosaccharides (FOS) have gained large commercial interest due to its beneficial properties in the human health as prebiotics. FOS are produced industrially by fermentative processes. However, the result of such fermentations is a complex mixture containing salts and approximately 50% (w/w) of low molecular weight sugars that have to be eliminated. Among other techniques that have been studied, the adsorption onto activated carbon is still the most suitable one since activated carbon is cheap, has a large surface area and pore volume conducting to a good sorption capacity. Furthermore, this sorbent can be regenerated during desorption with ethanol. Based on the above discussion, in this work the adsorption and desorption characteristics of FOS on activated carbon, using a gradient of ethanol, were optimized. Initially, the activated carbon was loaded with fermentative broth. To remove the non adsorbed sugars, a washing step with pure water was included. Afterwards, the retained sugars were recovered by elution with a gradient of ethanol increased sequentially with specific volumes from 1 to 50% (v/v). Fractions collected at different time points were evaporated and subsequently freeze‐dried. This process was found to be very efficient in the demineralization of broth, and it was possible to recover 80% of the initial FOS loaded on the column with 89% of purity. Some of the fractions were found to contain 97% of pure FOS in total sugars. In summary, purification of FOS using an activated charcoal column is a very efficient process yielding high levels of purity from a fermentative broth

Modeling and simulation of fructo-oligosaccharides production

It is foreseen that Systems Biology will have a great impact not only in Metabolic Engineering and Drug Discovery efforts, but also in Bioprocess development and optimization. In fact, the computational tools developed in this area made possible to simulate a biochemical process with a mathematical model comprising dynamical equations based on first principles as well as empirical kinetic equations and parameters that can be estimated from experimental data. Fructo-oligosaccharides (FOS) have become important as healthy food ingredients because of their beneficial characteristics to the health of human (Lee, 1999). They can be obtained biotechnologically using the enzyme Betafructofuranosidase, produced by some fungi. The main purpose of this work was to develop a mathematical model able to simulate the formation of FOS in a bioreactor, in order to perform a faster optimization of the FOS production process, allowing to identify which parameters can influence the final amount of FOS. An empirical model presented by Kow Jen Duan et al (1994) was used to obtain the first set of reactions. Several hydrolysis equations were added in order to achieve a general mathematical model of the occurring enzymatic reactions. After the reformulation of the Kow Jen Duan model, the kinetic parameters were determined from experimental data using the System Biology toolbox [2] with the Simulated Annealing method for curve fitting. Several experiments in bioreactors were performed with two different FOS producing fungi for that purpose. The time evolution of 7 state variables (Sucrose, Glucose, Fructose, 1-Kestose, Nystose, 1-Fructosyl Nystose and Biomass) was considered. After parameter fitting, several simulations were performed in MatLab and the simulation results were compared with experimental data, exhibiting a very satisfactory correlation for both fungal cultures. Correlation coefficients of 0.9980 - 0.9549 between simulated and experimental data were obtained. This model will be used to optimize the production process, using an optimization tool that has been developed in our research group

Purification of fructo-oligosaccharides by adsorption onto charcoal filters

Production of fructo-oligosaccharides has received particular attention recently due to its beneficial effects as prebiotics. Fermentative processes appear to be a good technique for large scale production of FOS. However, the result of such fermentations is a complex mixture containing salts and low molecular weight sugars that do not contribute to the beneficial properties of the higher molecular weight oligosaccharides, and so have to be eliminated. Among the several strategies being studied to solve this problem, the adorption onto activated carbon is a promising technique that still requires further development. Thus, the aim of this work was the purification of FOS from a fermentation broth using charcoal filters. Microfiltration membranes (0,20 micrometers) were successfully used to separate the biomass; nevertheless salts and other small sugars had to be eliminated using a charcoal filter. Hence, 200 mL of fermentative broth (without cells) was passed through the filter. Subsequently, the filter was washed with water removing the salts and small sugars present in the mixture. The oligosaccharides adsorbed onto the charcoal filter were recovered using a 44% ethanol solution. An increased purity, from 30% to 97% (w/w) in total sugars, was achieved using this downstream process, as compared to the initial mixture. The results gathered in this work suggest that charcoal filters are a promising technology for the purification of FOS from fermentation mixtures at an industrial scale, making clear the need for further work in order to optimize this process