Measuring and Controlling the Chaotic Motion of Profits

The study of economic systems has generated deep interest in exploring the complexity of chaotic motions in economy. Due to important developments in nonlinear dynamics, the last two decades have witnessed strong revival of interest in nonlinear endogenous business chaotic models. The inability to predict the behavior of dynamical systems in the presence of chaos suggests the application of chaos control methods, when we are more interested in obtaining regular behavior. In the present article, we study a specific economic model from the literature. More precisely, a system of three ordinary differential equations gather the variables of profits, reinvestments and financial flow of borrowings in the structure of a firm. Firstly, using results of symbolic dynamics, we characterize the topological entropy and the parameter space ordering of kneading sequences, associated with one-dimensional maps that reproduce significant aspects of the model dynamics. The analysis of the variation of this numerical invariant, in some realistic system parameter region, allows us to quantify and to distinguish different chaotic regimes. Finally, we show that complicated behavior arising from the chaotic firm model can be controlled without changing its original properties and the dynamics can be turned into the desired attracting time periodic motion (a stable steady state or into a regular cycle). The orbit stabilization is illustrated by the application of a feedback control technique initially developed by Romeiras et al. [1992]. This work provides another illustration of how our understanding of economic models can be enhanced by the theoretical and numerical investigation of nonlinear dynamical systems modeled by ordinary differential equations.

Complexes of copper(II) with 3-(ortho-substituted phenylhydrazo)pentane-2,4-diones: syntheses,properties and catalytic activity for cyclohexane oxidation

Reactions of copper(II) with 3-phenylhydrazopentane-2,4-diones X-2-C6H4-NHN = C{C(= O)CH3}(2) bearing a substituent in the ortho-position [X = OH (H2L1) 1, AsO3H2 (H3L2) 2, Cl (HL3) 3, SO3H (H2L4) 4, COOCH3 (HL5) 5, COOH (H2L6) 6, NO2 (HL7) 7 or H (HL8) 8] lead to a variety of complexes including the monomeric [CuL4(H2O)(2)]center dot H2O 10, [CuL4(H2O)(2)] 11 and [Cu(HL4)(2)(H2O)(4)] 12, the dimeric [Cu-2(H2O)(2)(mu-HL2)(2)] 9 and the polymeric [Cu(mu-L-6)](n)] 13 ones, often bearing two fused six-membered metallacycles. Complexes 10-12 can interconvert, depending on pH and temperature, whereas the Cu(II) reactions with 4 in the presence of cyanoguanidine or imidazole (im) afford the monomeric compound [Cu(H2O)(4){NCNC(NH2)(2)}(2)](HL4)(2)center dot 6H(2)O 14 and the heteroligand polymer [Cu(mu-L-4)(im)](n) 15, respectively. The compounds were characterized by single crystal X-ray diffraction (complexes), electrochemical and thermogravimetric studies, as well as elemental analysis, IR, H-1 and C-13 NMR spectroscopies (diones) and ESI-MS. The effects of the substituents in 1-8 on the HOMO-LUMO gap and the relative stability of the model compounds [Cu(OH)(L-8)(H2O)]center dot H2O, [Cu(L-1)(H2O)(2)]center dot H2O and [Cu(L-4)(H2O)(2)]center dot H2O are discussed on the basis of DFT calculations that show the stabilization follows the order: two fused 6-membered > two fused 6-membered/5-membered > one 6-membered metallacycles. Complexes 9, 10, 12 and 13 act as catalyst precursors for the peroxidative oxidation (with H2O2) of cyclohexane to cyclohexanol and cyclohexanone, in MeCN/H2O (total yields of ca. 20% with TONs up to 566), under mild conditions.

O efeito de um programa de fisioterapia na estabilização do prematuro

Mestrado em Fisioterapia.

Topological Complexity and Predictability in the Dynamics of a Tumor Growth Model with Shilnikov's Chaos

Dynamical systems modeling tumor growth have been investigated to determine the dynamics between tumor and healthy cells. Recent theoretical investigations indicate that these interactions may lead to different dynamical outcomes, in particular to homoclinic chaos. In the present study, we analyze both topological and dynamical properties of a recently characterized chaotic attractor governing the dynamics of tumor cells interacting with healthy tissue cells and effector cells of the immune system. By using the theory of symbolic dynamics, we first characterize the topological entropy and the parameter space ordering of kneading sequences from one-dimensional iterated maps identified in the dynamics, focusing on the effects of inactivation interactions between both effector and tumor cells. The previous analyses are complemented with the computation of the spectrum of Lyapunov exponents, the fractal dimension and the predictability of the chaotic attractors. Our results show that the inactivation rate of effector cells by the tumor cells has an important effect on the dynamics of the system. The increase of effector cells inactivation involves an inverse Feigenbaum (i.e. period-halving bifurcation) scenario, which results in the stabilization of the dynamics and in an increase of dynamics predictability. Our analyses also reveal that, at low inactivation rates of effector cells, tumor cells undergo strong, chaotic fluctuations, with the dynamics being highly unpredictable. Our findings are discussed in the context of tumor cells potential viability.

A especificidade do trabalho de Pontas no Ensino Artístico Especializado

Relatório Final de Estágio apresentado à Escola Superior de Dança com vista à obtenção do Grau de Mestre em Ensino de Dança.

Epidemiologic transition in northern Angola: discussion of cumulative results from CISA (Health Research Centre of Angola)

The 41 years of armed conflict (1961 to 2002) resulted in a poor development of the health care and education infrastructures, and forced the relocation of people to safer places, namely major urban cities like Luanda. This phase was characterized by typical demographic, nutritional and epidemiological profiles. With the end of this period Angola has been repeatedly ranked as one of the three fastest growing economies in the world, and along with the social stabilization and globalization, the country is facing the introduction of new medical technologies, improvement of health sys-tems and services, better access to them, and overall better quality of life. These changes could also be translating into socio-cultural, demographic and nutritional changes which in turn may leading to changes in the epidemiological profile of the country. Thus, the emergence of non-communicable diseases are likely to become an increasingly im-portant public health problem in Angola. Also, considering that several infectious diseases persist, our weakened health system will have to face a double burden. Thus, disease surveillance data on non-communicable diseases to determine their prevalence and impact, along with the major behavioural risk factors like consumption of tobacco, alcohol, diets and physical inactivity are urgently needed.

O efeito de um programa de fisioterapia na estabilização do prematuro

O número de bebés que nascem prematuros tem vindo a aumentar. É indiscutível a importância dos avanços tecnológicos e da pesquisa nas Unidades de Cuidados Intensivos de Neonatologia (UCIN), sendo essencial o papel desempenhado pelos fisioterapeutas nos cuidados prestados a estes bebés. As suas potencialidades só se desenvolvem na medida em que o bebé encontra estimulação e posicionamento adequado. Realizou‑se um estudo piloto na UCIN do Centro Hospitalar Lisboa Norte (CHLN), no período de julho de 2011 a março de 2012, em que se pretendeu avaliar o efeito de um programa de fisioterapia na estabilização do prematuro. Este programa consistiu em posicionar o prematuro em decúbito dorsal, lateral direito e lateral esquerdo e decúbito ventral, permanecendo em cada posição 5 minutos. O objetivo foi avaliar, durante a permanência do bebé na UCIN, a alteração nos seguintes parâmetros: frequência cardíaca (FC) e saturação de oxigénio (SatO2), antes e depois do tratamento. A amostra por conveniência incluiu no estudo 30 bebés prematuros, sendo 13 do género feminino e 17 do género masculino, que obedeceram a critérios específicos de inclusão. Para verificar as variáveis fisiológicas FC e SatO2 foi utilizado um Oxímetro de Pulso BCI 3401. Verificou‑se que a FC diminui e a SatO2 aumentou entre a primeira avaliação e a segunda avaliação, para a amostra total, assim como para os sujeitos do género feminino e os sujeitos do género masculino, para α = 0,05 e valor p≤0,001. Contudo, a diferença entre as médias dos dois momentos de avaliação da FC e da SatO2, em função do género, não revelaram diferenças estatisticamente significativas. Em conclusão, o estudo sugere que o programa de fisioterapia promove a melhoria da SatO2 e diminuição da FC, promovendo uma melhoria da estabilização do prematuro.

Análise crítica do Regulamento Geral dos Sistemas Públicos e Prediais de Distribuição de Água e de Drenagem de Águas Residuais

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Civil na Área de Especialização de Hidráulica

Eficácia do método Pilates no tratamento da dor lombar crónica: uma revisão sistemática da literatura

Mestrado em Fisioterapia

Design and construction of tunnels in zones subjected to high convergences

The economic development of a region depends on the speed that people and goods can travel. The reduction of people and goods travel time can be achieved by planning smooth road layouts, which are obtained by crossing natural obstacles such as hills, by tunneling at great depths, and allowing the reduction of the road alignment length. The stress state in rock masses at such depths, either because of the overburden or due to the tectonic conditions of the rock mass induces high convergences of the tunnel walls. These high convergence values are incompatible with the supports structural performance installed in the excavation stabilization. In this article it is intended to evaluate and analyze some of the solutions already implemented in several similar geological and geotechnical situations, in order to establish a methodological principle for the design of the tunnels included in a highway section under construction in the region influenced by the Himalayas, in the state of Himachal Pradesh (India) and referenced by "four laning of Kiratpur to Ner Chowk section".

Geological and geotechnical surveys in tectonically active rock masses

The economic development of a region depends on the speed that people and goods can travel. The reduction of people and goods travel time can be achieved by planning smooth road layouts, which are obtained by crossing natural obstacles such as hills, by tunneling at great depths, and allowing the reduction of the road alignment length. The stress state in rock masses at such depths, either because of the overburden or due to the tectonic conditions of the rock mass induces high convergences of the tunnel walls. These high convergence values are incompatible with the supports structural performance installed in the excavation stabilization. In this article it is intended to evaluate and analyze some of the solutions already implemented in several similar geological and geotechnical situations, in order to establish a methodological principle for the design of the tunnels included in a highway section under construction in the region influenced by the Himalayas, in the state of Himachal Pradesh (India) and referenced by "four laning of Kiratpur to Ner Chowk section".

On the requirements of interpolating polynomials for path motion constraints

In the framework of multibody dynamics, the path motion constraint enforces that a body follows a predefined curve being its rotations with respect to the curve moving frame also prescribed. The kinematic constraint formulation requires the evaluation of the fourth derivative of the curve with respect to its arc length. Regardless of the fact that higher order polynomials lead to unwanted curve oscillations, at least a fifth order polynomials is required to formulate this constraint. From the point of view of geometric control lower order polynomials are preferred. This work shows that for multibody dynamic formulations with dependent coordinates the use of cubic polynomials is possible, being the dynamic response similar to that obtained with higher order polynomials. The stabilization of the equations of motion, always required to control the constraint violations during long analysis periods due to the inherent numerical errors of the integration process, is enough to correct the error introduced by using a lower order polynomial interpolation and thus forfeiting the analytical requirement for higher order polynomials.