An observer-based vaccination control law for an SEIR epidemic model based on feedback linearization techniques for nonlinear systems

This paper presents a vaccination strategy for fighting against the propagation of epidemic diseases. The disease propagation is described by an SEIR (susceptible plus infected plus infectious plus removed populations) epidemic model. The model takes into account the total population amounts as a refrain for the illness transmission since its increase makes the contacts among susceptible and infected more difficult. The vaccination strategy is based on a continuous-time nonlinear control law synthesised via an exact feedback input-output linearization approach. An observer is incorporated into the control scheme to provide online estimates for the susceptible and infected populations in the case when their values are not available from online measurement but they are necessary to implement the control law. The vaccination control is generated based on the information provided by the observer. The control objective is to asymptotically eradicate the infection from the population so that the removed-by-immunity population asymptotically tracks the whole one without precise knowledge of the partial populations. The model positivity, the eradication of the infection under feedback vaccination laws and the stability properties as well as the asymptotic convergence of the estimation errors to zero as time tends to infinity are investigated.

On the impact of independence of irrelevant alternatives: the case of two-person NTU games

On several classes of n-person NTU games that have at least one Shapley NTU value, Aumann characterized this solution by six axioms: Non-emptiness, efficiency, unanimity, scale covariance, conditional additivity, and independence of irrelevant alternatives (IIA). Each of the first five axioms is logically independent of the remaining axioms, and the logical independence of IIA is an open problem. We show that for n = 2 the first five axioms already characterize the Shapley NTU value, provided that the class of games is not further restricted. Moreover, we present an example of a solution that satisfies the first five axioms and violates IIA for two-person NTU games (N, V) with uniformly p-smooth V(N).

Robust Sliding Control of SEIR Epidemic Models

This paper is aimed at designing a robust vaccination strategy capable of eradicating an infectious disease from a population regardless of the potential uncertainty in the parameters defining the disease. For this purpose, a control theoretic approach based on a sliding-mode control law is used. Initially, the controller is designed assuming certain knowledge of an upper-bound of the uncertainty signal. Afterwards, this condition is removed while an adaptive sliding control system is designed. The closed-loop properties are proved mathematically in the nonadaptive and adaptive cases. Furthermore, the usual sign function appearing in the sliding-mode control is substituted by the saturation function in order to prevent chattering. In addition, the properties achieved by the closed-loop system under this variation are also stated and proved analytically. The closed-loop system is able to attain the control objective regardless of the parametric uncertainties of the model and the lack of a priori knowledge on the system.

Stability analysis and observer design for discrete-time SEIR epidemic models

This paper applies Micken's discretization method to obtain a discrete-time SEIR epidemic model. The positivity of the model along with the existence and stability of equilibrium points is discussed for the discrete-time case. Afterwards, the design of a state observer for this discrete-time SEIR epidemic model is tackled. The analysis of the model along with the observer design is faced in an implicit way instead of obtaining first an explicit formulation of the system which is the novelty of the presented approach. Moreover, some sufficient conditions to ensure the asymptotic stability of the observer are provided in terms of a matrix inequality that can be cast in the form of a LMI. The feasibility of the matrix inequality is proved, while some simulation examples show the operation and usefulness of the observer.

Sensing parasites: proteomic and advanced bio-detection alternatives

[EN] Parasitic diseases have a great impact in human and animal health. The gold standard for the diagnosis of the majority of parasitic infections is still conventional microscopy, which presents important limitations in terms of sensitivity and specificity and commonly requires highly trained technicians. More accurate molecular-based diagnostic tools are needed for the implementation of early detection, effective treatments and massive screenings with high-throughput capacities. In this respect, sensitive and affordable devices could greatly impact on sustainable control programmes which exist against parasitic diseases, especially in low income settings. Proteomics and nanotechnology approaches are valuable tools for sensing pathogens and host alteration signatures within microfluidic detection platforms. These new devices might provide novel solutions to fight parasitic diseases. Newly described specific parasite derived products with immune-modulatory properties have been postulated as the best candidates for the early and accurate detection of parasitic infections as well as for the blockage of parasite development. This review provides the most recent methodological and technological advances with great potential for biosensing parasites in their hosts, showing the newest opportunities offered by modern “-omics” and platforms for parasite detection and control.

On the Stability and Equilibrium Points of Multistaged SI (n) R Epidemic Models

This paper relies on the concept of next generation matrix defined ad hoc for a new proposed extended SEIR model referred to as SI(n)R-model to study its stability. The model includes n successive stages of infectious subpopulations, each one acting at the exposed subpopulation of the next infectious stage in a cascade global disposal where each infectious population acts as the exposed subpopulation of the next infectious stage. The model also has internal delays which characterize the time intervals of the coupling of the susceptible dynamics with the infectious populations of the various cascade infectious stages. Since the susceptible subpopulation is common, and then unique, to all the infectious stages, its coupled dynamic action on each of those stages is modeled with an increasing delay as the infectious stage index increases from 1 to n. The physical interpretation of the model is that the dynamics of the disease exhibits different stages in which the infectivity and the mortality rates vary as the individual numbers go through the process of recovery, each stage with a characteristic average time.

Sensing parasites: proteomic and advanced bio-detection alternatives

[EN] Parasitic diseases have a great impact in human and animal health. The gold standard for the diagnosis of the majority of parasitic infections is still conventional microscopy, which presents important limitations in terms of sensitivity and specificity and commonly requires highly trained technicians. More accurate molecular-based diagnostic tools are needed for the implementation of early detection, effective treatments and massive screenings with high-throughput capacities. In this respect, sensitive and affordable devices could greatly impact on sustainable control programmes which exist against parasitic diseases, especially in low income settings. Proteomics and nanotechnology approaches are valuable tools for sensing pathogens and host alteration signatures within micro fluidic detection platforms. These new devices might provide novel solutions to fight parasitic diseases. Newly described specific parasite derived products with immune-modulatory properties have been postulated as the best candidates for the early and accurate detection of parasitic infections as well as for the blockage of parasite development. This review provides the most recent methodological and technological advances with great potential for biosensing parasites in their hosts, showing the newest opportunities offered by modern “-omics” and platforms for parasite detection and control.

Los Modelos Implícitos de Valoración de Opciones

[ES] Los modelos implícitos constituyen uno de los enfoques de valoración de opciones alternativos al modelo de Black-Scholes que ha conocido un mayor desarrollo en los últimos años. Dentro de este planteamiento existen diferentes alternativas: los árboles implícitos, los modelos con función de volatilidad determinista y los modelos con función de volatilidad implícita. Todos ellos se construyen a partir de una estimación de la distribución de probabilidades riesgo-neutral del precio futuro del activo subyacente, congruente con los precios de mercado de las opciones negociadas. En consecuencia, los modelos implícitos proporcionan buenos resultados en la valoración de opciones dentro de la muestra. Sin embargo, su comportamiento como instrumento de predicción para opciones fuera de muestra no resulta satisfactorio. En este artículo se analiza la medida en la que este enfoque contribuye a la mejora de la valoración de opciones, tanto desde un punto de vista teórico como práctico.

System for ampacity monitoring and low sag overhead conductor evaluation

MELECON 2012 - 2012 16th IEEE Mediterranean Electrotechnical Conference, 25 Mar - 28 Mar 2012, Túnez

In vitro activities of natural products against oral Candida isolates from denture wearers

Background: Candida-associated denture stomatitis is a frequent infectious disease. Treatment of this oral condition is difficult because failures and recurrences are common. The aim of this study was to test the in vitro antifungal activity of pure constituents of essentials oils. -- Methods: Eight terpenic derivatives (carvacrol, farnesol, geraniol, linalool, menthol, menthone, terpinen-4-ol, and aterpineol), a phenylpropanoid (eugenol), a phenethyl alcohol (tyrosol) and fluconazole were evaluated against 38 Candida isolated from denture-wearers and 10 collection Candida strains by the CLSI M27-A3 broth microdilution method. -- Results: Almost all the tested compounds showed antifungal activity with MIC ranges of 0.03-0.25% for eugenol and linalool, 0.03-0.12% for geraniol, 0.06-0.5% for menthol, a-terpineol and terpinen-4-ol, 0.03-0.5% for carvacrol, and 0.06-4% for menthone. These compounds, with the exception of farnesol, menthone and tyrosol, showed important in vitro activities against the fluconazole-resistant and susceptible-dose dependent Candida isolates. -- Conclusions: Carvacrol, eugenol, geraniol, linalool and terpinen-4-ol were very active in vitro against oral Candida isolates. Their fungistatic and fungicidal activities might convert them into promising alternatives for the topic treatment of oral candidiasis and denture stomatitis.

La ley de propiedad intelectual y su repercusión en la actividad de las bibliotecas

[ES]Se analizan las repercusiones que la legislación y las nuevas tecnologías tienen en las bibliotecas en relación a la propiedad intelectual. También se examina el papel que han de tener las bibliotecas en la gestión de aspectos de la propiedad intelectual y las opciones alternativas de publicación en el ámbito académico (Open Access, repositorios)

Tax-Based Fisheries Management: The Case Study Of The Cantabrian Anchovy Fishery

A dynamic optimisation framework is adopted to show how tax-based management systems theoretically correct the inefficient allocation of fishing resources derived from the stock externality. Optimal Pigouvian taxes on output (τ) and on inputs (γ) are calculated, compared and considered as potential alternatives to the current regulation of VIII division Cantabrian anchovy fishery. The sensibility analysis of optimal taxes illustrates an asymmetry between (τ) and (γ) when cost price ratio varies. The distributional effects also differ. Special attention will be paid to the real implementation of the tax-based systems in fisheries.

Asistencia, recuperación y restauración de las víctimas

[ES] Junto con formas simples de restitución y compensación, se han detectado variantes de las primeras prácticas de justicia restaurativa en las antiguas civilizaciones de Israel, Sumeria, Babilonia y Roma y entre los pueblos aborígenes de Norteamérica y Oceanía. Por su parte, en el siglo XX, principalmente en respuesta a la ola criminal de los años 60 y 70, y buscando alternativas a los métodos tradicionales de tratamiento de los delitos de esa época, comenzaron a emerger programas experimentales que usaban los principios de justicia restaurativa a comienzos de los 70 en Canadá, Estados Unidos, Inglaterra, Australia y Nueva Zelanda.

Democratic Values Transmission

This study addresses the issue of intergenerational transmission of democratic values embedded in social choice rules. We focus on a few rules which have been the focus of social choice theory: plurality, plurality with a runoff, majoritarian compromise, social compromise and Borda rule. We confront subjects with preferences profiles of a hypothetical electorate over a set of four alternatives. Different rules produce different outcomes and subjects decide which alternative should be chosen for the society whose preference profile is shown. We elicit each subject's preferences over rules and his/her parents' and check whether there is any relationship; 186 students and their parents attended the sessions at Istanbul Bilgi University. Overall, we find support for the hypothesis of parental transmission of democratic values and gender differences in the transmitted rule.

Cost effectiveness of a combination of instruments for global warming: a quantitative approach for Spain

Climate change is an important environmental problem and one whose economic implications are many and varied. This paper starts with the presumption that mitigation of greenhouse gases is a necessary policy that has to be designed in a cost effective way. It is well known that market instruments are the best option for cost effectiveness. But the discussion regarding which of the various market instruments should be used, how they may interact and what combinations of policies should be implemented is still open and very lively. In this paper we propose a combination of instruments: the marketable emission permits already in place in Europe for major economic sectors and a CO(2) tax for economic sectors not included in the emissions permit scheme. The study uses an applied general equilibrium model for the Spanish economy to compute the results obtained with the new mix of instruments proposed. As the combination of the market for emission permits and the CO(2) tax admits different possibilities that depend on how the mitigation is distributed among the economic sectors, we concentrate on four possibilities: cost-effective, equalitarian, proportional to emissions, and proportional to output distributions. Other alternatives to the CO(2) tax are also analysed (tax on energy, on oil and on electricity). Our findings suggest that careful, well designed policies are needed as any deviation imposes significant additional costs that increase more than proportionally to the level of emissions reduction targeted by the EU.