Mitigation of symmetry condition in positive realness for adaptive control

Feasibility of nonlinear and adaptive control methodologies in multivariable linear time-invariant systems with state-space realization (A, B, C) is apparently limited by the standard strictly positive realness conditions that imply that the product CB must be positive definite symmetric. This paper expands the applicability of the strictly positive realness conditions used for the proofs of stability of adaptive control or control with uncertainty by showing that the not necessarily symmetric CB is only required to have a diagonal Jordan form and positive eigenvalues. The paper also shows that under the new condition any minimum-phase systems can be made strictly positive real via constant output feedback. The paper illustrates the usefulness of these extended properties with an adaptive control example. (C) 2006 Elsevier Ltd. All rights reserved.

Realimentação da derivada dos estados em sistemas multivariáveis lineares usando LMIs

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

Early nephrology consultation can have an impact on outcome of acute kidney injury patients

Background. Patients who develop acute kidney injury (AKI) in the intensive care unit (ICU) have extremely high rates of mortality and morbidity. The objectives of this study were to compare clinical and laboratory characteristics of AKI patients evaluated and not evaluated by nephrologists in ICU and generate the hypothesis of the relationship between timing of nephrology consultation and outcome.Methods. We explored associations among presence and timing of nephrology consultation with ICU stay and in-ICU mortality in 148 ICU patients with AKI at a Brazilian teaching hospital from July 2008 to May 2010. Multivariable logistic regression was used to adjust confounding and selection bias.Results. AKI incidence was 30% and 52% of these AKI patients were evaluated by nephrologists. At multivariable analysis, AKI patients evaluated by nephrologists showed higher Acute Tubular Necrosis-Index Specific Score and creatinine level, more dialysis indications, lower urine output and longer ICU stay. The mortality rate was similar to AKI patients who were not evaluated. Nephrology consultation was delayed (>= 48 h) in 62.3% (median time to consultation, 4.7 days). Lower serum creatinine levels (P - 0.009) and higher urine output (P = 0.002) were associated with delayed consultation. Delayed consultation was associated with increased ICU mortality (65.4 versus 88.2%, P < 0.001).Conclusions. In AKI, patients evaluated by nephrologists seem to be more seriously ill than those not evaluated and present similar mortality rate. The delayed nephrology consultation can be associated with increased ICU mortality.

Knowledge and attitudes of health care workers from intensive care units regarding nosocomial transmission of influenza: a study on the immediate pre-pandemic period

The transmission of influenza in health care settings is a major threat to patients, especially those with severe diseases. The attitude of health care workers (HCWs) may influence the transmission of countless infections. The current study aimed to quantify knowledge and identify attitudes of HCWs involved in intensive care units (ICUs) regarding the risk of nosocomial influenza transmission. A questionnaire was applied through interviews to HCWs who worked in one of the five ICUs from a teaching hospital. Questions about influenza were deliberately dispersed among others that assessed several infectious agents. Forty-two HCWs were interviewed: nine physicians, ten nurses and 23 nursing technicians or auxiliaries. Among the 42 HCWs, 98% were aware of the potential transmission of influenza virus in the ICUs, but only 31% would indicate droplet precautions for patients with suspected infection. Moreover, only 31% of them had been vaccinated against influenza in the last campaign (2008). Nursing technicians or auxiliaries were more likely to have been vaccinated, both by univariate and multivariable analysis. When asked about absenteeism, only 10% of the study subjects stated that they would not go to work if they had an influenza-like illness. Those findings suggest that, in non-pandemic periods, influenza control in hospitals requires strategies that combine continuous education with changes in organizational culture.

Risk factors for Hospital-Acquired Pneumonia in nonventilated adults

Although most recent publications focus on Ventilator-associated Pneumonia, Non-Ventilator-associated Hospital-acquired pneumonia (NVHAP) is still worrisome. We studied risk factors for NVHAP among patients admitted to a small teaching hospital. Sixty-six NVHAP case patients and 66 controls admitted to the hospital from November 2005 through November 2006 were enrolled in a case-control study. Variables under investigation included: demographic characteristics, comorbidities, procedures, invasive devices and use of medications (Sedatives, Antacids, Steroids and Antimicrobials). Univariate and multivariable analysis (hierarchical models of logistic regression) were performed. The incidence of NVHAP in our hospital was 0.68% (1.02 per 1,000 patients-day). Results from multivariable analysis identified risk factors for NVHAP: age (Odds Ratio[OR]=1.03, 95% Confidence Interval[CI]=1.01-1.05, p=0.002), use of Antacids (OR=5.29, 95%CI=1.89-4.79, p=0.001) and Central Nervous System disease (OR=3.13, 95%CI=1.24-7.93, p=0.02). Although our findings are coherent with previous reports, the association of Antacids with NVHAP recalls a controversial issue in the physiopathology of Hospital-Acquired Pneumonia, with possible implications for preventive strategies.

Molar Pregnancy in Adolescents

OBJECTIVE: To describe the clinical presentation of hydatidiform molar pregnancy in women under the age of 20 years. In addition, we sought to understand if this adolescent population manifests differences in clinical factors compared to an adult population that may affect outcome.STUDY DESIGN: We used a database from the New England Trophoblastic Disease Center to analyze clinical data from all women followed for molar pregnancy between 1970 and 2009 with complete follow-up information. This population was stratified by age and clinical parameters including presenting signs, molar histology and development of gestational trophoblastic neoplasia (GTN). Univariable and multivariable logistic regression was employed to discern clinical factors that associated with adolescent age. The Partners Human Research Committee approved this study.RESULTS: We identified 1,494 women diagnosed with hydatidiform mole (HM), of which 220 (14.7%) were adolescents defined as age <20 years. The most common presenting clinical signs were vaginal bleeding and an enlarged uterus compared to dates. Median gestational age at diagnosis was 13.4 weeks, not different from that in the adult population. Similarly, no difference in presenting human chorionic gonadotropin was observed between the adult and adolescent populations. Adolescents presented with a significant overrepresentation of complete mole (86% vs. 75%, p < 0.001) compared to adults. Complete mole was associated with a heightened risk of developing GTN (OR 2.6, 95% CI 1.9-3.5), and despite the association of complete mole with young maternal age, univariable analysis showed no difference in the rate of GTN observed between adolescents and adults (24% vs. 30%, p = 0.08). Multivariable analysis controlling for molar histology demonstrated that adolescent age was associated with a decreased risk of GTN (hazard ratio 0.67, 95% CI 0.48 0.93).CONCLUSION: Adolescents account for a substantial proportion of the population with HM. They commonly present with vaginal bleeding. Though this population develops a complete mole with a higher frequency than adults, adolescents appear to have a significantly decreased risk of developing GTN. (J Reprod Med 2012; 57:225-230)

Transtornos mentais comuns e uso de psicofármacos: impacto das condições socioeconômicas

OBJETIVO: Avaliar a influência das condições socioeconômicas na associação entre transtornos mentais comuns, uso de serviços de saúde e de psicofármacos. MÉTODOS: Estudo transversal populacional conduzido na cidade de Botucatu, SP, com amostragem probabilística, estratificada e por conglomerados. Foram realizadas entrevistas domiciliares com 1.023 sujeitos de 15 anos ou mais de idade, entre 2001 e 2002. Transtorno mental comum foi avaliado utilizando o Self Reporting Questionnaire (SRQ-20). O uso de serviços foi investigado com relação à quinzena anterior à entrevista e uso de psicotrópicos, nos três dias anteriores. Utilizou-se regressão logística para análise multivariável, considerando o efeito do desenho. RESULTADOS: No total da amostra, 13,4% (IC 95%: 10,7;16,0) procuraram serviços de saúde na quinzena anterior à entrevista. A procura de serviços de saúde se associou ao sexo feminino (OR=2,0) e à presença de transtorno mental comum (OR=2,2). Na amostra 13,3% (IC 95%: 9,2;17,5) referiram ter usado ao menos um psicotrópico, destacando-se os antidepressivos (5,0%) e os benzodiazepínicos (3,1%). Na análise multivariável, sexo feminino e presença de transtorno mental comum mantiveram-se associados ao uso de benzodiazepínicos. Renda per capita mostrou-se direta e independentemente associada ao uso de psicofármacos, conforme aumento da renda. CONCLUSÕES: Menor renda associou-se à presença de transtorno mental comum, mas não ao uso de psicotrópicos. A associação entre transtorno mental comum e uso de psicotrópicos e maior renda reforça a hipótese da existência de iniqüidades no acesso à assistência médica na população estudada.

Fatores de risco associados à mortalidade de recém-nascidos de muito baixo peso na cidade de Botucatu, São Paulo, no período 1995-2000

OBJETIVOS: avaliar as práticas assistenciais, a ocorrência de doenças, a mortalidade durante a hospitalização e os fatores associados em recém-nascidos prematuros de muito baixo peso (PT-MBP). MÉTODOS: estudo transversal comparando dois períodos: 1995-1997 e 1998-2000 e envolvendo todos os PT-MBP nascidos vivos (n= 451), em um centro perinatal, em Botucatu, São Paulo, Brasil. Os fatores de risco pré-natal e pós-natal foram submetidos a análise multivariada. RESULTADOS: a mortalidade diminuiu de 36,2% para 29,5%. A sobrevida melhorou e foi superior a 50% a partir de 28 semanas e de 750 g de peso. O uso de corticosteróide antenatal aumentou de 25% para 42%, o surfactante exógeno de 14% para 28%, com redução na incidência e gravidade da síndrome do desconforto respiratório. A regressão logística mostrou que a síndrome do desconforto respiratório grave, Odds ratio=18, e a sepse precoce, Odds ratio=2,8, foram importantes fatores de risco para morte em 1995-1997. No período de 1998-2000, a sepse precoce e tardia, Odds ratio=10,5 e 12, respectivamente, aumentaram o risco de morte. CONCLUSÕES: a melhora na assistência perinatal diminuiu a mortalidade do PT-MBP. O aumento na exposição antenatal ao corticosteróide diminuiu a gravidade da síndrome do desconforto respiratório. em 1998-2000, a sepse foi o único fator de risco para morte.

Walking for leisure among adults from three Brazilian cities and its association with perceived environment attributes and personal factors

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Gaussian quadrature rules with simple node-weight relations

In this paper, we consider the symmetric Gaussian and L-Gaussian quadrature rules associated with twin periodic recurrence relations with possible variations in the initial coefficient. We show that the weights of the associated Gaussian quadrature rules can be given as rational functions in terms of the corresponding nodes where the numerators and denominators are polynomials of degree at most 4. We also show that the weights of the associated L-Gaussian quadrature rules can be given as rational functions in terms of the corresponding nodes where the numerators and denominators are polynomials of degree at most 5. Special cases of these quadrature rules are given. Finally, an easy to implement procedure for the evaluation of the nodes is described.

Zeros of Jacobi functions of second kind

The number of zeros in (- 1, 1) of the Jacobi function of second kind Q(n)((alpha, beta)) (x), alpha, beta > - 1, i.e. The second solution of the differential equation(1 - x(2))y (x) + (beta - alpha - (alpha + beta + 2)x)y' (x) + n(n + alpha + beta + 1)y(x) = 0,is determined for every n is an element of N and for all values of the parameters alpha > - 1 and beta > - 1. It turns out that this number depends essentially on alpha and beta as well as on the specific normalization of the function Q(n)((alpha, beta)) (x). Interlacing properties of the zeros are also obtained. As a consequence of the main result, we determine the number of zeros of Laguerre's and Hermite's functions of second kind. (c) 2005 Elsevier B.V. All rights reserved.

Landau and Kolmogoroff type polynomial inequalities

Let 0polynomials of degree not exceeding n).For the particular case j=1 and m=2, we provide a complete characterisation of the positive constants A and B, for which the corresponding Landau type polynomial inequalities parallel to f'parallel to less than or equal toA parallel to f parallel to + B parallel to f parallel to/ A theta(k) + B mu(k)hold. In each case we determine the corresponding extremal polynomials for which equalities are attained.

On a symmetry in strong distributions

A strong Stieltjes distribution d psi(t) is called symmetric if it satisfies the propertyt(omega) d psi(beta(2)/t) = -(beta(2)/t)(omega) d psi(t), for t is an element of (a, b) subset of or equal to (0, infinity), 2 omega is an element of Z, and beta > 0.In this article some consequences of symmetry on the moments, the orthogonal L-polynomials and the quadrature formulae associated with the distribution are given. (C) 1999 Elsevier B.V. B.V. All rights reserved.

Schur-SzegA composition of entire functions

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

Multiscale Fractal Descriptors and Polynomial Classifier for Partial Pixels Identification in Regions of Interest of Mammographic Images

Computer systems are used to support breast cancer diagnosis, with decisions taken from measurements carried out in regions of interest (ROIs). We show that support decisions obtained from square or rectangular ROIs can to include background regions with different behavior of healthy or diseased tissues. In this study, the background regions were identified as Partial Pixels (PP), obtained with a multilevel method of segmentation based on maximum entropy. The behaviors of healthy, diseased and partial tissues were quantified by fractal dimension and multiscale lacunarity, calculated through signatures of textures. The separability of groups was achieved using a polynomial classifier. The polynomials have powerful approximation properties as classifiers to treat characteristics linearly separable or not. This proposed method allowed quantifying the ROIs investigated and demonstrated that different behaviors are obtained, with distinctions of 90% for images obtained in the Cranio-caudal (CC) and Mediolateral Oblique (MLO) views.