Dynamic Morse decompositions for semigroups of homeomorphisms and control systems

In this paper, we introduce the concept of dynamic Morse decomposition for an action of a semigroup of homeomorphisms. Conley has shown in [5, Sec. 7] that the concepts of Morse decomposition and dynamic Morse decompositions are equivalent for flows in metric spaces. Here, we show that a Morse decomposition for an action of a semigroup of homeomorphisms of a compact topological space is a dynamic Morse decomposition. We also define Morse decompositions and dynamic Morse decompositions for control systems on manifolds. Under certain condition, we show that the concept of dynamic Morse decomposition for control system is equivalent to the concept of Morse decomposition.

Factors associated with the prevalence of hypertension and control practices among elderly residents of São Paulo city, Brazil

The aim of this study was to analyze the prevalence of hypertension and control practices among the elderly. The survey analyzed data from 872 elderly people in São Paulo, Brazil, through a cluster sampling, stratified according to education and income. A Poisson multiple regression model checked for the existence of factors associated with hypertension. The prevalence of self-reported hypertension among the elderly was 46.9%. Variables associated with hypertension were self-rated health, alcohol consumption, gender, and hospitalization in the last year, regardless of age. The three most common measures taken to control hypertension, but only rarely, are oral medication, routine salt-free diet and physical activity. Lifestyle and socioeconomic status did not affect the practice of control, but knowledge about the importance of physical activity was higher among those older people with higher education and greater income. The research suggests that health policies that focus on primary care to encourage lifestyle changes among the elderly are necessary.

Nucleus isthmi and control of breathing in amphibians

Despite recent advances, the mechanisms of neurorespiratory control in amphibians are far from understood. One of the brainstem structures believed to play a key role in the ventilatory control of anuran amphibians is the nucleus isthmi (NI). This nucleus is a mesencephalic structure located between the roof of the midbrain and the cerebellum, which differentiates during metamorphosis; the period when pulmonary ventilation develops in bullfrogs. It has been recently suggested that the NI acts to inhibit hypoxic and hypercarbic drives in breathing by restricting increases in tidal volume. This data is similar to the influence of two pontine structures of mammals, the locus coeruleus and the nucleus raphe magnus. The putative mediators for this response are glutamate and nitric oxide. Microinjection of kynurenic acid (an ionotropic receptor antagonist of excitatory amino acids) and L-NAME (a non-selective NO synthase inhibitor) elicited increases in the ventilatory response to hypoxia and hypercarbia. This article reviews the available data on the role of the NI in the control of ventilation in amphibians. (C) 2004 Elsevier B.V. All rights reserved.

Efficiency of entomopathogenic fungi in the control of eggs and larvae of the horn fly Haematobia irritans (Diptera: Muscidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Adrenergic mechanisms of the Kölliker-Fuse/A7 area on the control of water and sodium intake

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

On non-linear dynamics and control designs applied to the ideal and non-ideal variants of the Fitzhugh-Nagumo (FN) mathematical model

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mathematical modeling and control of population systems: Applications in biological pest control

The aim of this paper is to apply methods from optimal control theory, and from the theory of dynamic systems to the mathematical modeling of biological pest control. The linear feedback control problem for nonlinear systems has been formulated in order to obtain the optimal pest control strategy only through the introduction of natural enemies. Asymptotic stability of the closed-loop nonlinear Kolmogorov system is guaranteed by means of a Lyapunov function which can clearly be seen to be the solution of the Hamilton-Jacobi-Bellman equation, thus guaranteeing both stability and optimality. Numerical simulations for three possible scenarios of biological pest control based on the Lotka-Volterra models are provided to show the effectiveness of this method. (c) 2007 Elsevier B.V. All rights reserved.

Control of retention and fatigue-free characteristics in CaBi4Ti4O15 thin films prepared by chemical method

Ferroelectric CaBi4Ti4O15 (CBTi144) thin films were deposited on Pt/Ti/SiO2/Si substrates by the polymeric precursor method. The films present a single phase of layered-structured perovskite with polar axis orientation after annealing at 700 degrees C for 2 h in static air and oxygen atmosphere. The a/b-axis orientation of the ferroelectric film is considered to be associated with the preferred orientation of the Pt bottom electrode. It is noted that the films annealed in static air showed good polarization fatigue characteristics at least up to 10(10) bipolar pulse cycles and excellent retention properties up to 10(4) s. on the other hand, oxygen atmosphere seems to be crucial in the decrease of both, fatigue and retention characteristics of the capacitors. Independently of the applied electric field, the retained switchable polarization approached a nearly steady-state value after a retention time of 10 s. (C) 2006 Elsevier B.V. All rights reserved.

Effect of doses of fungicides and plant resistance activators on the control of Rhizoctonia foliar blight of soybean, and on Rhizoctonia solani AG1-IA in vitro development

Rhizoctonia foliar blight (RFB) of soybean [Glycine max (L.) Merrill] occurs in many tropical and subtropical regions, causing yield reductions of up to 70% and in Brazil, up to 60%. The disease is caused by Rhizoetonia solani AG1-IA and AG1-IB, and by AG2-3 in Japan. RFB occurs in the North, Northeast and Mid-west regions of Brazil. Chemical control remains the only effective method of controlling RFB, but its efficiency depends upon environmental conditions. In this study, 18 fungicides, salicylic acid (SA) and acibenzolar-s-methyl (ASM) were evaluated on R. solani AG1-IA in vitro, by mycelial growth rating and estimating effective concentration for 50% (EC 50) and 90% (EC 90) inhibition of mycelial growth, and in vivo by reduction of disease severity on soybean plants in greenhouse conditions. Mycelial growth was strongly inhibited by the fungicides pyraclostrobin + boscalid and fludioxonil. Preventive fungicide applications were the most effective. Strobilurins were more efficient both in preventive and curative applications. Best results with plant resistance activators were obtained with SA (2.5 mM) sprayed at 20 d before inoculation and with ASM (12.5 mg a.i. l(-1)) 10 d before inoculation. (c) 2005 Elsevier Ltd. All rights reserved.

Postural control as a function of self- and object-motion perception

The goals of this study were to examine the visual information influence on body sway as a function of self- and object-motion perception and visual information quality. Participants that were aware (object-motion) and unaware (self-motion) of the movement of a moving room were asked to stand upright at five different distances from its frontal wall. The visual information effect on body sway decreased when participants were aware about the sensory manipulation. Moreover, while the visual influence on body sway decreased as the distance increased in the self-motion perception, no effects were observed in the object-motion mode. The overall results indicate that postural control system functioning can be altered by prior knowledge, and adaptation due to changes in sensory quality seem to occur in the self- but not in the object-motion perception mode. (C) 2004 Elsevier B.V.. All rights reserved.

Effect of propolis on postharvest control of anthracnose and quality parameters of 'Kent'mango

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Soil attributes and efficiency of sulfentrazone on control of purple nutsedge (Cyperus rotundus L.)

Herbicidas aplicados ao solo são submetidos à adsorção, lixiviação e degradação por processos físicos, químicos e biológicos, além da absorção pelas plantas. Todos esses processos são afetados pela classe dos solos onde foram aplicados e das condições climáticas reinantes logo após a aplicação, que afetarão a eficiência dos produtos no controle de plantas daninhas. Investigaram-se as influências dos atributos de solos e condições de cultivo na eficiência do herbicida sulfentrazone no controle da planta daninha tiririca (Cyperus rotundus L.). O Latossolo Vermelho-Amarelo Distrófico (LVAd), o Latossolo Vermelho (LVd - Distrófico; LVdf - Distroférrico; LVef - Eutroférrico) e o Nitossolo Vermelho Eutrófico (NVe) foram coletados sob duas condições de cultivo, visando obter solos com teores diferenciados de argila, óxido de ferro e matéria orgânica. As amostras dos solos foram submetidas à caracterização granulométrica, química e mineralógica e, em seguida, utilizadas no bioensaio de avaliação da eficiência do sulfentrazone (1,6 L p.c. ha-1) no controle da tiririca em condições de pré-emergência. O sulfentrazone apresentou comportamento diferenciado entre as classes de solos estudados e a sua eficiência diminuiu com o aumento do teor de óxido de ferro nos solos, na seguinte ordem: LVAd, LVd, NVe, LVef e LVdf, sendo que as variações nos teores de argila (240 a 640 g kg-1) e da matéria orgânica (12 a 78 g kg-1) dos solos não interferiram na eficiência do sulfentrazone.

Biochemical dissection of diageotropica and Never ripe tomato mutants to Cd-stressful conditions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The improvement of the anti-hyperalgesic effect of ketamine and of its isomers by the administration of ifenprodil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)