A dynamical point of view of Quantum Information: entropy and pressure

Quantum Information is a new area of research which has been growing rapidly since last decade. This topic is very close to potential applications to the so called Quantum Computer. In our point of view it makes sense to develop a more "dynamical point of view" of this theory. We want to consider the concepts of entropy and pressure for "stationary systems" acting on density matrices which generalize the usual ones in Ergodic Theory (in the sense of the Thermodynamic Formalism of R. Bowen, Y. Sinai and D. Ruelle). We consider the operator $\mathcal{L}$ acting on density matrices $\rho\in \mathcal{M}_N$ over a finite $N$-dimensional complex Hilbert space $\mathcal{L}(\rho):=\sum_{i=1}^k tr(W_i\rho W_i^*)V_i\rho V_i^*,$ where $W_i$ and $V_i$, $i=1,2,...k$ are operators in this Hilbert space. $\mathcal{L}$ is not a linear operator. In some sense this operator is a version of an Iterated Function System (IFS). Namely, the $V_i\,(.)\,V_i^*=:F_i(.)$, $i=1,2,...,k$, play the role of the inverse branches (acting on the configuration space of density matrices $\rho$) and the $W_i$ play the role of the weights one can consider on the IFS. We suppose that for all $\rho$ we have that $\sum_{i=1}^k tr(W_i\rho W_i^*)=1$. A family $W:=\{W_i\}_{i=1,..., k}$ determines a Quantum Iterated Function System (QIFS) $\mathcal{F}_{W}$, $\mathcal{F}_W=\{\mathcal{M}_N,F_i,W_i\}_{i=1,..., k}.

A dynamical point of view of Quantum Information: Wigner measures

We analyze a known version of the discrete Wigner function and some connections with Quantum Iterated Funcion Systems. This paper is a follow up of "A dynamical point of view of Quantum Information: entropy and pressure" by the same authors

A Thermodynamic Formalism for density matrices in Quantum Information

We consider new concepts of entropy and pressure for stationary systems acting on density matrices which generalize the usual ones in Ergodic Theory. Part of our work is to justify why the definitions and results we describe here are natural generalizations of the classical concepts of Thermodynamic Formalism (in the sense of R. Bowen, Y. Sinai and D. Ruelle). It is well-known that the concept of density operator should replace the concept of measure for the cases in which we consider a quantum formalism. We consider the operator $\Lambda$ acting on the space of density matrices $\mathcal{M}_N$ over a finite $N$-dimensional complex Hilbert space $$\Lambda(\rho):=\sum_{i=1}^k tr(W_i\rho W_i^*)\frac{V_i\rho V_i^*}{tr(V_i\rho V_i^*)},$$ where $W_i$ and $V_i$, $i=1,2,..., k$ are linear operators in this Hilbert space. In some sense this operator is a version of an Iterated Function System (IFS). Namely, the $V_i\,(.)\,V_i^*=:F_i(.)$, $i=1,2,...,k$, play the role of the inverse branches (i.e., the dynamics on the configuration space of density matrices) and the $W_i$ play the role of the weights one can consider on the IFS. In this way a family $W:=\{W_i\}_{i=1,..., k}$ determines a Quantum Iterated Function System (QIFS). We also present some estimates related to the Holevo bound

Sanitizing the fortress: protection of ant brood and nest material by worker antibiotics

Social groups are at particular risk for parasite infection, which is heightened in eusocial insects by the low genetic diversity of individuals within a colony. To combat this, adult ants have evolved a suite of defenses to protect each other, including the production of antimicrobial secretions. However, it is the brood in a colony that are most vulnerable to parasites because their individual defenses are limited, and the nest material in which ants live is also likely to be prone to colonization by potential parasites. Here, we investigate in two ant species whether adult workers use their antimicrobial secretions not only to protect each other but also to sanitize the vulnerable brood and nest material. We find that, in both leaf-cutting ants and weaver ants, the survival of the brood was reduced and the sporulation of parasitic fungi from them increased, when the workers nursing them lacked functional antimicrobial-producing glands. This was the case for both larvae that were experimentally treated with a fungal parasite (Metarhizium) and control larvae which developed infections of an opportunistic fungal parasite (Aspergillus). Similarly, fungi were more likely to grow on the nest material of both ant species if the glands of attending workers were blocked. The results show that the defense of brood and sanitization of nest material are important functions of the antimicrobial secretions of adult ants and that ubiquitous, opportunistic fungi may be a more important driver of the evolution of these defenses than rarer, specialist parasites

Parentalidade nos primeiros três anos da criança : stress e coping auto relatados pelos pais

Comunicação apresentada no XVII Congresso Internacional INFAD que decorreu em Zamora em 2010.Introdução e objectivo: A parentalidade envolve acontecimentos stressantes que exigem suporte pelo que se objectiva descrever situações de stress sentidas pelos cuidadores na educação da criança e o tipo de coping adoptado. Método: Estudo descritivo constituído por amostra acidental de 106 pais de crianças até 3 anos de idade. A informação recolhida por questionário foi analisada e agrupada em categorias. Resultados: Pelo menos uma situação de stress foi mencionada por 70% dos pais. As situações mais mencionadas pelas mães referiram-se a problemas de saúde da criança à resposta a necessidades básicas da criança, ao choro e ao comportamento da criança; e pelos pais à resposta a necessidades básicas da criança e ao choro da criança. As situações difíceis foram, com diferenças estatisticamente significativas, mais relatadas nos factores relacionados com a criança pelos cuidadores com filhos dois ou mais filhos (U=506,000; p=0,016). A maioria dos cuidadores respondeu ao problema procurando apoio, mas houve estratégias centradas na emoção e ausência de estratégias. Conclusões: Os resultados evidenciam áreas de necessidade de intervenção no apoio aos pais para uma parentalidade positiva

Contaminação com patógenos em sistemas hidropônico: como aparecem e como evitar.

bitstream/CNPH-2009/31446/1/cot_31.pd

Parenting in the first three years of the child: stress and coping self reported by parents

Introducción y objetivo: la crianza incluye eventos estresantes que requieren apoyo. El propósito de este estudio es describir situaciones de estrés experimentado por los padres en el papel parental y el tipo de estrategias de afrontamiento adoptadas. Método: Estudio descriptivo de una muestra de conveniencia de 106 padres de niños menores de 3 años de edad que completó un cuestionario. Los datos fueron analizados y agrupados en categorías. Resultados: Al menos una situación de estrés fue mencionada por el 70% de los padres. Las situaciones mencionadas por las madres conciernen a los problemas de salud de los niños, la respuesta a sus necesidades básicas, el llanto y el comportamiento del niño. Los padres mencionaron las necesidades del niño y el llanto. No hubo diferencias estadísticamente significativas en las situaciones difíciles relacionadas con los niños entre los padres y los padres de un solo hijo con dos o más hijos (U = 506.000; P0016). La mayoría de los padres respondieron el problema mediante la búsqueda de apoyo social. Hubo también estrategias centradas en las emociones y algunos de ellos no han adoptado estrategias. Conclusiones: Los resultados muestran áreas que necesitan intervención para apoyar a los padres en una crianza positiva.Introduction and Aim: Parenting involves stressful events that require support. The purpose of this study is to describe stress situations experienced by parents in the parental role and the type of coping strategies adopted. Method: A descriptive study of convenience sample of 106 parents of children under 3 years old completed a questionnaire. The data was analyzed and grouped into categories. Results: At least one stressful situation was mentioned by 70% of parents. The situations mentioned by mothers concerned the problems of child health, the answer to the basic needs of the child, the crying and the child’s behaviour. The fathers mentioned the needs of the child and the child’s crying. There were statistically significant differences in the difficult situations related to child between single child’s parents and parents with two or more children (U=506,000; p=0,016). Most parents answered the problem by seeking social support. There were also emotion-focused strategies and some of them have not adopted strategies. Conclusions: The results show areas that need intervention to support parents in a positive parenting.RESUMO. Introdução e objectivo: A parentalidade envolve acontecimentos stressantes que exigem suporte pelo que se objectiva descrever situações de stress sentidas pelos cuidadores na educação da criança e o tipo de coping adoptado. Método: Estudo descritivo constituído por amostra acidental de 106 pais de crianças até 3 anos de idade. A informação recolhida por questionário foi analisada e agrupada em categorias. Resultados: Pelo menos uma situação de stress foi mencionada por 70% dos pais. As situações mais mencionadas pelas mães referiram-se a problemas de saúde da criança à resposta a necessidades básicas da criança, ao choro e ao comportamento da criança; e pelos pais à resposta a necessidades básicas da criança e ao choro da criança. As situações difíceis foram, com diferenças estatisticamente significativas, mais relatadas nos factores relacionados com a criança pelos cuidadores com filhos dois ou mais filhos (U=506,000; p=0,016). A maioria dos cuidadores respondeu ao problema procurando apoio, mas houve estratégias centradas na emoção e ausência de estratégias. Conclusões: Os resultados evidenciam áreas de necessidade de intervenção no apoio aos pais para uma parentalidade positiva.peerReviewe