Data-based control design methods most often consist of iterative adjustment of the controller's parameters towards the parameter values which minimize an H2 performance criterion. Typically, batches of input-output data collected from the system are used to feed directly a gradient descent optimization - no process model is used. The convergence to the global minimum of the performance criterion depends on the initial controller parameters and on the step size of each iteration. This paper discusses these issues and provides a method for choosing the step size to ensure convergence to the global minimum utilizing the lowest possible number of iterations.

PURPOSE: The aim of the present crossover study was to evaluate professional toothbrushing as a method for diagnosing gingivitis in children. MATERIALS AND METHODS: Thirty-four preschool children who had gingival bleeding > or = 10% and without proximal restorations/carious lesions were included in the study. Examinations comprised two gingival indices recorded at a 15-min interval, in the following sequences: the Ainamo and Bay gingival bleeding index (GBI1) followed by the brushing index (BI2) and vice versa (BI1-GBI2). Half of the children started the study in the first sequence and the other half in the second. After a 3- to 4-day washout period, the indices were again recorded with individuals changing the sequences. Data analysis considered GBI as the gold standard, and sensitivity (SE), specificity (SP), positive predictive value (PPV) and negative predictive value (NPV) were also calculated. RESULTS: The overall mean value of gingival bleeding at the first examination was 18.85 +/- 9.24%. Validation of toothbrushing performed after GBI (BI2) resulted in values for SE, SP, PPV and NPV of 0.59 (95% CI, 0.55 to 0.63), 0.92 (95% CI, 0.91 to 0.93), 0.64 (95% CI, 0.60 to 0.69) and 0.90 (95% CI, 0.89 to 0.92), respectively. BI performed before GBI (BI1) resulted in similar SE, SP, PPV and NPV. Percentage agreement of GBI1-BI2 and BI1-GBI2 was 83.5% and 85.9%, respectively. CONCLUSIONS: Professional toothbrushing can be suggested as a method for the diagnosis of gingival inflammatory status in children, especially as an indicator of gingival health.

Este artigo prolonga a análise do argumento apresentado por Descartes em favor da primeira certeza no início da Segunda Meditação, iniciada em um artigo anterior. É examinada a passagem subsequente ao referido argumento com vistas a estabelecer que sua compreensão aponta para um debate velado entre Descartes e seus leitores versa- dos na doutrina escolástica, mais particularmente nas concepções da definição como estruturada pela composição do gênero e da diferença e de específica e de conceito universal abstrato. Procuro mostrar que as razões que Des- cartes dispõe para recusar essas concepções podem ser extraídas de certa interpretação do argumento em favor da certeza da proposição eu existo e que essa recusa é imprescindível para a compreensão adequada do penso, logo existo e, portanto, de seu argumento em favor do dualismo.

Este artigo prolonga a análise do argumento apresentado por Descartes em favor da primeira certeza no início da Segunda Meditação, iniciada em um artigo anterior. É examinada a passagem subsequente ao referido argumento com vistas a estabelecer que sua compreensão aponta para um debate velado entre Descartes e seus leitores versa- dos na doutrina escolástica, mais particularmente nas concepções da definição como estruturada pela composição do gênero e da diferença e de específica e de conceito universal abstrato. Procuro mostrar que as razões que Des- cartes dispõe para recusar essas concepções podem ser extraídas de certa interpretação do argumento em favor da certeza da proposição eu existo e que essa recusa é imprescindível para a compreensão adequada do penso, logo existo e, portanto, de seu argumento em favor do dualismo.

Judgments about the validity of at least some elementary inferential patterns (say modus ponens) are a priori if anything is. Yet a number of empirical conditions must in each case be satisfied in order for a particular inference to instantiate this or that inferential pattern. We may on occasion be entitled to presuppose that such conditions are satisfied (and the entitlement may even be a priori), yet only experience could tell us that such was indeed the case. Current discussion about a perceived incompatibility between content externalism and first-person authority exemplifies how damaging the neglect of such empirical presuppositions of correct reasoning can be. An externalistic view of mental content is ostensibly incompatible with the assumption that a rational subject should be able to avoid inconsistency no matter what the state of her empirical knowledge may be. That fact, however, needs not be taken (as it often is) as a reductio of externalism: alternatively, we may reject that assumption, adding to the agenda of a philosophical investigation of rationality an examination of the vicissitudes of logical luck. I offer an illustration and defense of that alternative.

In this work was investigated the effect of pre-treatment with (PhSe) 2 and (PhTe) 2 on chemical seizure and 4-aminopyridine-induced lethality in mice. Additionally, lipid peroxidation levels of whole brain after treatment with 4-aminopyridine and effect of pre-treatment with (PhSe) 2 and (PhTe) 2 on these levels were investigated. Mice were pre-treated with (PhSe) 2 or (PhTe) 2 (50, 100, or 150 $μ$mol/kg) 30 min before 4-aminopyridine (12 mg/kg) administration. The treatment with 4-aminopyridine caused a significant incidence of seizures (clonic, tonic) and death. Pre-treatment with (PhSe) 2 and (PhTe) 2 significantly increased the latency for clonic and tonic seizures, and prevented 4-aminopyridine-induced death. Significantly, the pre-treatment with (PhSe) 2 or (PhTe) 2 increased the latency for clonic seizures in a dose-dependent manner. Additionally, a significant increase was observed in the brain lipid peroxidation level after treatment with 4-aminopyridine, which was significantly inhibited by pre-treatment with 150 $μ$mol/kg (PhSe) 2 or (PhTe) 2 . These results demonstrate that (PhSe) 2 and (PhTe) 2 counteract the harmful effects of 4-aminopyridine. It is possible that this effect results from modulation of the redox state of N-methyl-d-aspartate receptors and/or of Ca 2+ channel activity with subsequent alteration in neurotransmitter release. Importantly, this study provides evidence for anticonvulsant and antioxidant properties of (PhSe) 2 and (PhTe) 2′ which indicates a neuroprotective activity of these compounds.