Nonequilibrium Probabilistic Dynamics of the Logistic Map at the Edge of Chaos

We consider nonequilibrium probabilistic dynamics in logistic-like maps $x_{t+1}=1-a|x_t|^z$, $(z>1)$ at their chaos threshold: We first introduce many initial conditions within one among $W>>1$ intervals partitioning the phase space and focus on the unique value $q_{sen}<1$ for which the entropic form $S_q \equiv \frac{1-\sum_{i=1}^{W} p_i^q}{q-1}$ {\it linearly} increases with time. We then verify that $S_{q_{sen}}(t) - S_{q_{sen}}(\infty)$ vanishes like $t^{-1/[q_{rel}(W)-1]}$ [$q_{rel}(W)>1$]. We finally exhibit a new finite-size scaling, $q_{rel}(\infty) - q_{rel}(W) \propto W^{-|q_{sen}|}$. This establishes quantitatively, for the first time, a long pursued relation between sensitivity to the initial conditions and relaxation, concepts which play central roles in nonextensive statistical mechanics.Comment: Final version with new Title and small modifications. REVTeX, 8 pages and 4 eps figure

Logarithmic diffusion and porous media equations: a unified description

In this work we present the logarithmic diffusion equation as a limit case when the index that characterizes a nonlinear Fokker-Planck equation, in its diffusive term, goes to zero. A linear drift and a source term are considered in this equation. Its solution has a lorentzian form, consequently this equation characterizes a super diffusion like a L\'evy kind. In addition is obtained an equation that unifies the porous media and the logarithmic diffusion equations, including a generalized diffusion equation in fractal dimension. This unification is performed in the nonextensive thermostatistics context and increases the possibilities about the description of anomalous diffusive processes.Comment: 5 pages. To appear in Phys. Rev.

Relação entre geologia, ventilação natural e concentração de gás radão: caso de estudo no noroeste de Portugal

Alto Minho region, Northwest of Portugal, presents high indoor radon concentrations due to the granitic nature of the soil. Indoor radon concentration is related to the amount of uranium and radium in the building foundation soil. According to the World Health Organization, it is proved that radon exposure in poorly ventilated buildings enhances lung cancer risk. An assessment campaign in a set of granitic buildings in the Alto Minho region, based on short-term measurements, was carried out with a specific focus on the influence of occupancy and ventilation actions performed by residents on the variation of radon concentration, indoor air temperature, and relative humidity. Results attained show to exist an influence of the air renovation on the reduction of radon concentration, therefore, buildings with low occupancy and reduced ventilation present higher indoor radon concentration and poor thermal comfort conditions. 67% of the evaluated buildings show radon concentrations below the reference value of 300 Bq.m−3 suggested by Portuguese regulation, highlighting the importance of human occupancy – mostly through passive ventilation processes – as a radon concentration mitigation factor. On the other hand, buildings sporadically occupied and, therefore, badly ventilated show higher indoor radon concentrations. Likewise, building where occupants reveal to have a lack of ventilation routine, present also high indoor radon concentrations.A região do Alto Minho, Noroeste de Portugal, apresenta altas concentrações de gás radão em ambientes interiores devido à natureza granítica do solo. A concentração no ar interior de gás radão está relacionada com a quantidade de urânio e rádio no solo de fundação do edifício. De acordo com a Organização Mundial de Saúde, está provado que a exposição ao gás radão em edifícios mal ventilados incrementa o risco de cancro do pulmão. Foi realizada uma campanha de instrumentação tendo como objeto de estudo um conjunto de edifícios graníticos na região do Alto Minho, baseada em medições de curta duração, tendo como foco específico, a influência da ocupação e da ventilação dos edifícios na variação da concentração de gás radão, temperatura do ar interior e humidade relativa. Os resultados obtidos mostram existir uma influência das ações de ventilação na redução da concentração de gás radão. Deste modo, edifícios com baixa ocupação e, portanto, com menor renovação do ar, apresentam elevada concentração de gás radão e deficientes condições de conforto térmico. De facto, 67% dos edifícios avaliados apresentam concentrações de gás radão abaixo do valor de referência de 300 Bq.m−3 indicado na regulamentação portuguesa, evidenciando a importância da ocupação humana e dos processos de ventilação natural adotados, como fator de mitigação da concentração de radão. Por outro lado, edifícios esporadicamente ocupados e, portanto, mal ventilados apresentam concentrações mais elevadas de radão. Da mesma forma, edifícios onde os ocupantes não têm hábitos de ventilação apresentam de igual forma concentrações de gás radão mais elevadas.info:eu-repo/semantics/publishedVersio

Nonlinear equation for anomalous diffusion: unified power-law and stretched exponential exact solution

The nonlinear diffusion equation $\frac{\partial \rho}{\partial t}=D \tilde{\Delta} \rho^\nu$ is analyzed here, where $\tilde{\Delta}\equiv \frac{1}{r^{d-1}}\frac{\partial}{\partial r} r^{d-1-\theta} \frac{\partial}{\partial r}$, and $d$, $\theta$ and $\nu$ are real parameters. This equation unifies the anomalous diffusion equation on fractals ($\nu =1$) and the spherical anomalous diffusion for porous media ($\theta=0$). Exact point-source solution is obtained, enabling us to describe a large class of subdiffusion ($\theta > (1-\nu)d$), normal diffusion ($\theta= (1-\nu)d$) and superdiffusion ($\theta < (1-\nu)d$). Furthermore, a thermostatistical basis for this solution is given from the maximum entropic principle applied to the Tsallis entropy.Comment: 3 pages, 2 eps figure

Generating functions for generalized binomial distributions

In a recent article a generalization of the binomial distribution associated with a sequence of positive numbers was examined. The analysis of the nonnegativeness of the formal expressions was a key-point to allow to give them a statistical interpretation in terms of probabilities. In this article we present an approach based on generating functions that solves the previous difficulties: the constraints of nonnegativeness are automatically fulfilled, a complete characterization in terms of generating functions is given and a large number of analytical examples becomes available.Comment: PDFLaTex, 27 pages, 5 figure

Generalized Heisenberg Algebras and Fibonacci Series

We have constructed a Heisenberg-type algebra generated by the Hamiltonian, the step operators and an auxiliar operator. This algebra describes quantum systems having eigenvalues of the Hamiltonian depending on the eigenvalues of the two previous levels. This happens, for example, for systems having the energy spectrum given by Fibonacci sequence. Moreover, the algebraic structure depends on two functions f(x) and g(x). When these two functions are linear we classify, analysing the stability of the fixed points of the functions, the possible representations for this algebra.Comment: 24 pages, 2 figures, subfigure.st

Analysis of return distributions in the coherent noise model

The return distributions of the coherent noise model are studied for the system size independent case. It is shown that, in this case, these distributions are in the shape of q-Gaussians, which are the standard distributions obtained in nonextensive statistical mechanics. Moreover, an exact relation connecting the exponent $\tau$ of avalanche size distribution and the q value of appropriate q-Gaussian has been obtained as q=(tau+2)/tau. Making use of this relation one can easily determine the q parameter values of the appropriate q-Gaussians a priori from one of the well-known exponents of the system. Since the coherent noise model has the advantage of producing different tau values by varying a model parameter \sigma, clear numerical evidences on the validity of the proposed relation have been achieved for different cases. Finally, the effect of the system size has also been analysed and an analytical expression has been proposed, which is corroborated by the numerical results.Comment: 14 pages, 3 fig

Joining sustainable design and internet of things technologies on campus : the IPVC smartbottle practical case

Higher education institutions (HEIs) are favored environments for the implementation of technological solutions that accelerate the generation of smart campi, given the dynamic ecosystem they create based on the involvement of inspired and motivated human resources (students, professors, and researchers), moving around in an atmosphere of advanced digital infrastructures and services. Moreover, HEIs have, in their mission, not only the creation of integrated knowledge through Research and Development (R&D) activities but also solving societal problems that address the academic community expectations concerning environmental issues, contributing, therefore, towards a greener society embodied within the United Nations (UN) Sustainable Development Goals (SDGs). This article addresses the design and implementation of a Smartbottle Ecosystem in which an interactive and reusable water bottle communicates with an intelligent water refill station, both integrated by the Internet of Things (IoT) and Information and Communications Technologies (ICT), to eliminate the use of single-use plastic water bottles in the premises of the Polytechnical Institute of Viana do Castelo (IPVC), an HEI with nearly 6000 students. Three main contributions were identified in this research: (i) the proposal of a novel methodology based on the association of Design Thinking and Participatory Design as the basis for Sustainable Design; (ii) the design and development of an IoT-enabled smartbottle prototype; and (iii) the usability evaluation of the proposed prototype. The adopted methodology is rooted in Design Thinking and mixes it with a Participatory Design approach, including the end-user opinion throughout the Smartbottle Ecosystem design process, not only for the product design requirements but also for its specification. By promoting a participatory solution tailored to the IPVC academic community, recycled plastic has been identified as the preferential material and a marine mammal was selected for the smartbottle shape, in the process of developing a solution to replace the single-use plastic bottles.7519-C505-DF9E | Ant?nio Jos? Candeias CuradoN/

Fusió de la teoria del decreixement i la de bens comuns

L'objectiu d'aquest article científic és començar a treballar en la fusió de dues línies de pensament les quals, ja per si soles, tenen una gran potència explicativa: La teoria del decreixement i la de bens comuns. Parlem de fusió ja que, més que posar en relació aquestes dues línies de pensament, es té la intenció d'aportar evidències de que el decreixement ha d'ésser comunal, i que la conservació i producció respectuosa dels bens comuns només es pot donar plenament en el marc del decreixement. En l'ànima d'aquest assaig batega un intent de reformular l'esquerra. Es busca trobar institucions socials en les que s'uneixin la solidaritat social i l'empoderament polític, per a assolir una comunitat en la qual el creixement estigui sotmès al ritme de regeneració de la biosfer