3,386 research outputs found
Entropic Steering Criteria: Applications to Bipartite and Tripartite Systems
The effect of quantum steering describes a possible action at a distance via
local measurements. Whereas many attempts on characterizing steerability have
been pursued, answering the question as to whether a given state is steerable
or not remains a difficult task. Here, we investigate the applicability of a
recently proposed method for building steering criteria from generalized
entropic uncertainty relations. This method works for any entropy which satisfy
the properties of (i) (pseudo-) additivity for independent distributions; (ii)
state independent entropic uncertainty relation (EUR); and (iii) joint
convexity of a corresponding relative entropy. Our study extends the former
analysis to Tsallis and R\'enyi entropies on bipartite and tripartite systems.
As examples, we investigate the steerability of the three-qubit GHZ and W
states.Comment: 27 pages, 8 figures. Published version. Title change
Implementation of a specific rate controller in a fed-batch E. coli fermentation
The specific growth rate is one of the most important process variables characterizing the state of microorganisms during fermentations mainly because the
biosynthesis of many products of interest is often related with the values assumed by this parameter. In the particular case of the fed-batch operation of Escherichia coli for the production of recombinant proteins, it is important to maintain the specific growth rate below a certain threshold in order to avoid the accumulation of acetic acid throughout the fermentation and, additionally, it is often argued that both pre- and the post-induction specific growth rates should be closely controlled in order to achieve maximum productivities of the desired recombinant protein.
In a previous work the authors have developed and validated by simulations a strategy for the automatic control of the specific growth rate in E. coli fed-batch fermentations based on an asymptotic observer for biomass and on developed estimators for the specific growth rates. The main purpose of the present work was to implement experimentally the
developed observer, estimator and controller in a real fed-batch fermentation process. For that purpose a data acquisition and control program was developed in LabVIEW that allows the acquisition of the necessary on line data (off gas and dissolved oxygen concentration and culture weight) and the calculation of the feeding rates using the
developed equations. The feedforward-feedback controller developed was able to keep the culture growing in an exponential phase throughout the fermentation without accumulation of glucose and acetate.Fundação para a Ciência e a Tecnologia (FCT) - RecSysBio projecto POCI/BIO/60139/200
Multi-level dynamic modeling in biological systems : application of hybrid Petri nets to network simulation
The recent progress in the high-throughput experimental technologies allows the reconstruction of many biological networks and to evaluate changes in proteins, genes and metabolites levels in different conditions. On the other hand, computational models, when complemented with regulatory information, can be used to predict the phenotype of an organism under different genetic and environmental conditions. These computational methods can be used for example to identify molecular targets capable of inactivating a bacterium and to understand its virulence factors. This work proposes a hybrid metabolic-regulatory Petri net approach that is based on the combination of approximate enzyme-kinetic rate laws and Petri nets. A prototypic network model is used as a test-case to illustrate the application of these concepts in Systems Biology.This work was partially supported by post-doctoral grant by Fundacao para a Ciencia e a Tecnologia (FCT) (SFRH/BPD/80784/2011), project PneumoSyS - A Systems Biology approach to the role of pneumococcal carbon metabolism in colonization and invasive disease (FCT contract: PTDC/SAU-MII/100964/2008) and by FCT (INESC-ID multiannual funding) through the PIDDAC program funds
Assessment of sediment contamination in an impacted estuary: differential effects and adaptations of sentinel organisms and implications for biomonitoring
Conferência realizada em Lisboa, de 6-9 November de 2013Estuarine pollution is reflected in the concentration of toxicants in sediments, depending on their geochemical properties, since sediments trap substances from the water column, either dissolved or bound to suspended matter. However, determining risk of sediment contaminants to biota has many constraints. For such reason, integrative approaches are keystone. Taking the Sado estuary (SW Portugal) as a case study, contrasted to a reference estuary (the Mira) within the same geographical location, the present study aimed at integrating sediment contamination with the effects and responses to pollutants in distinct benthic organisms with commercial and ecological value
Draft genome sequence of vibrio sp. strain Evh12, a bacterium retrieved from the gorgonian coral eunicella verrucosa.
To shed light on the associations established between Vibrio species and soft corals in coastal ecosystems, we report here the draft genome sequence of Vibrio sp. strain Evh12, a bacterium that has been isolated from the gorgonian coral Eunicella verrucosa and that shows antagonistic activity against Escherichia coli
Comparative study about heating systems for pultrusion process
Different heating systems have been used in pultrusion, where the most widely used heaters are planar resistances. The primary objective of this study was to develop an improved heating system and compare its performance with that of a system with planar resistances. In this study, thermography was used to better understand the temperature profile along the die. Finite element analysis was performed to determine the amount of energy consumed by the heating systems. Improvements were made to the die to test the new heating system, and it was found that the new system reduced the setup time and energy consumption by approximately 57%
Internal variation temperature analysis and thermal mapping of a central processing unit (CPU)
This work aims to analyze the internal temperature variation of the central processing unit (CPU) of a personal computer, through the development of three distinct scenarios: one for reference and two aiming at its performance improvement. The finite volume method (FVM) was applied. Thus, Hypermesh 13.0 software was used for geometric model development and for surface mesh generation. For model contour conditions configuration, virtual simulation and post-processing, Starccm+ software was used. The results of this work indicated hot spots due to the heat dissipated during the operation of the CPU components. As expected, the processor region presented the highest temperatures in all proposed scenarios. The opening on the side of the cabinet, proposed in scenario 2, allowed a temperature reduction of about 18 °C in the processor region. In turn, scenario 3, in which heat exchangers were used in order to minimize the temperature of the hot air from the recirculation in the processor region, showed a minimum temperature reduction (about 3 °C) when compared to scenario 1
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