194,829 research outputs found
Solving dynamical inverse problems by means of metabolic P systems
No full textMP (Metabolic P) systems are a class of P systems introduced for modelling metabolic processes. We refer to the dynamical inverse problem as the problem of identifying (discrete) mathematical models exhibiting an observed dynamics. In this paper, we complete the definition of the algorithm LGSS (Log-gain Stoichiometric Stepwise regression) introduced in Manca and Marchetti (2011) for solving a general class of dynamical inverse problems. To this aim, we develop a reformulation of the classical stepwise regression in the context of MP systems. We conclude with a short review of two applications of LGSS for discovering the internal regulation logic of two phenomena relevant in systems biology
P. Manca, International Maritime Law
No full textP. Manca, International Maritime Law. In: Revue internationale de droit comparé. Vol. 25 N°3, Juillet-septembre 1973. pp. 773-775
Risultati della ricerca
No full textUna ricerca che sviluppa una riflessione pedagogica sulle pratiche didattiche inclusive per alunni stranieri nella scuola dell'infanzia e primari
P. Manca, International Maritime Law
No full textP. Manca, International Maritime Law. In: Revue internationale de droit comparé. Vol. 25 N°3, Juillet-septembre 1973. pp. 773-775
Change from lung adenocarcinoma to small cell lung cancer as a mechanism of resistance to afatinib
No full textWe report the case of a patient affected by advanced EGFR mutation-positive lung who experienced resistance to therapy during treatment with Afatinib through the occurrence of a switch of tumor histotype to small cell lung cancer (SCLC) with features of a G3 neuroendocrine carcinoma. Unexpectedly, the switch to SCLC histotype occurred in the only site not responsive to afatinib and subsequently the most responsive to chemotherapy. Our case shows that occurrence of switch to SCLC is a possible mechanism of resistance during treatment with Afatinib.Copyright: Manca et al
Proposta di un modello matematico per la previsione del comportamento tecnologico di miscele ceramiche artistiche
No full textThe paper deal with the suitability of Sardinian clays in mixture for ceramics craft, using statistical model based on multiple regression of their main parameter.
The study consist in two part: the first is the characterization of the local material and the comparison with the common material used by potters, and coming from national market.
The second part is the realization of a statistical design model based on measured data, useful for the prevision of technological property of the final ceramics product from clays pre-firing characteristics.
In particular, the model from the particle size distribution (PSD), the chemical composition, the Atterberg limits can predict the Loss off Ignition (LoI), the Water Absorption (WA), the Linear Firing Shrinkage (LFS) and the Dilatometry (DIL) of ceramics fired between temperature from 800° to 1200° C.
The model is obtained with multivariate analysis (correlation and cluster analysis), and it is tested in a preliminary application
Kinetics of heavy metals leaching from contaminated soils in metallurgical plants
No full textKinetics of Heavy Metals Leaching from Contaminated Soils in Metallurgical Plants
Paolo Desogus , Pier Paolo Manca , Giampaolo Orrù
Abstract
The work aims to highlight the main parameters that affect the efficiency of the process of leaching of heavy metals from a natural soil taken from inside a metallurgical plant. The studies were conducted by laboratory tests and the results will allow identifying the fundamental choices for the applications of the technique of in situ soil flushing.
The tested soil samples were mainly made by fine silica sand, with medium density. Their pollution was caused by waste of the metallurgy of lead and zinc released into the soil to transport by rainwater. Their depth ranges from 1 to 2 meters from ground the level from which they are separated by artificial strata composed of soil mixed with metallurgical solid waste. The layer of soil tested hosts an aquifer with a slow permeability, variable depth generally higher than 10m contaminated by heavy metals.
The leaching experiments were conducted through the batch and column tests. Acid solutions (acetic. nitric. hydrochloric and sulfuric) were used as extracting agents. During the leaching tests, concentrations of analytics Zn, Pb, Cd, Cu, Mn and Al were verified.
The results highlighted two aspects: (a) the conditions for which they get the best efficiency of leaching and (b) the laws of statistical correlation that describe the kinetics of reaction. The calculations performed have shown that the most efficient leaching agent was the CH3COOH and mainly the flow velocity of the leaching solution conditions the reaction kinetics in the column
Predator-prey dynamics in P systems ruled by metabolic algorithm
No full textP systems are used to compute predator-prey dynamics expressed in the traditional formulation by Lotka and Volterra. By governing the action of the transition rules in such systems using the regulatory features of the metabolic algorithm we come up with simulations of the Lotka-Volterra equations, whose robustness is comparable to that obtained using Runge-Kutta schemes and Gillespie's Stochastic Simulation Algorithm. Besides their reliability, the results obtained using the metabolic algorithm on top of P systems have a clear biochemical interpretation concerning the role, of reactants or promoters, of the species involved
Discrete Solution of Differential Equations by P Metabolic Algorithm
No full textThe relationships existing between MP graphs, metabolic P systems, and
ODE systems are investigated. Formal results show that every MP system, once derived
by its MP graph, results in an ODE system whose solution equals, in the limit, the solution
obtained by a non-cooperative MP system that is ODE equivalent to the original one.
The freedom of choice of the ODE equivalent from the original MP system resembles the
same freedom which is left in the choice and optimization of a numerical scheme while
computing the solution of an ODE system
The metabolic algorithm for P systems: Principles and applications
No full textAbstractMetabolic P systems, shortly MP systems, are a special class of P systems, introduced for expressing biological metabolism. An MP system evolution is given by a metabolic algorithm, a deterministic strategy, where the classical viewpoint on metabolic dynamics, in terms of ordinary differential equations, is replaced by suitable generalizations of chemical principles. The basic principles of MP systems are given and their main aspects are explained by means of examples of biological modeling. A new kind of regulation mechanism is outlined, which could be the basis for a more efficient construction of computational models from experimental data of specific metabolic processes
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