APPROXIMATE CALCULATION OF SUMS I: BOUNDS FOR THE ZEROS OF GRAM POLYNOMIALS

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Zero sets of bivariate Hermite polynomials

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Para-orthogonal polynomials from constant Verblunsky coefficients

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estimation of genetic parameters for partial egg production periods by means of random regression models

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

On the zeros of polynomials: An extension of the Enestrom-Kakeya theorem

This paper presents an extension of the Enestrom-Kakeya theorem concerning the roots of a polynomial that arises from the analysis of the stability of Brown (K, L) methods. The generalization relates to relaxing one of the inequalities on the coefficients of the polynomial. Two results concerning the zeros of polynomials will be proved, one of them providing a partial answer to a conjecture by Meneguette (1994)[6]. (C) 2011 Elsevier B.V. All rights reserved.

Relativistic confinement of neutral fermions with a trigonometric tangent potential

The problem of neutral fermions subject to a pseudoscalar potential is investigated. Apart from the solutions for E = +/- mc(2), the problem is mapped into the Sturm-Liouville equation. The case of a singular trigonometric tangent potential (similar to tan gamma x) is exactly solved and the complete set of solutions is discussed in some detail. It is revealed that this intrinsically relativistic and true confining potential is able to localize fermions into a region of space arbitrarily small without the menace of particle-antiparticle production.

Waveshapes of continuing currents and properties of M-components in natural positive cloud-to-ground lightning

This work analyses the waveshapes of continuing currents and parameters of M-components in positive cloud-to-ground (CG) flashes through high-speed GPS synchronized videos. The dataset is composed of only long continuing currents (with duration longer than 40 ms) and was selected from more than 800 flashes recorded in Sao Jose dos Campos (45.864 degrees W, 23.215 degrees S) and Uruguaiana (29.806 degrees W, 57.005 degrees S) in Southeast and South of Brazil, respectively, during 2003 to 2007 summers. The videos are compared with data obtained by the Brazilian Lightning Location System (BrasilDAT) in order to determine the polarity of each flash and select only positive cases. There are only two studies of waveshapes of continuing currents in the literature. One is based on direct current measurements of triggered lightning, in which four different types of waveshapes were observed; and the other is based on measurements of luminosity variations in high-speed videos of CG negative lightning, in which besides the four types above mentioned two additional types were observed. The present work is an extension of the latter, using the same method but now applied to obtain the waveshapes of positive CG lightning. As far as the authors know, this is the first report on M-components in positive continuing currents. We also have used the luminosity-versus-time graphs to observe their occurrence and measure some parameters (duration, elapsed time and time between two successive M-components), whose statistics are presented and compared in detail to the data for negative flashes. We have plotted a histogram of the M-components elapsed time over the total duration of the continuing current for positive flashes, which presented an exponential decay (correlation coefficient: 0.83), similar to what has been observed for negative flashes. (C) 2008 Elsevier B.V. All rights reserved.

Positive leader characteristics from high-speed video observations

Based on analyses of high-speed video recordings of cloud-to-ground lightning in Brazil and the USA, the characteristics of positive cloud-to-ground (+CG) leaders are presented. The high frame rates permitted the average, 2-dimensional speeds of development along the paths of the channels to be resolved with good accuracy. The values range from 0.3 to 6.0 x 10(5) ms(-1) with a mean of 2.7 x 10(5) ms(-1). Contrary to what is usually assumed, downward +CG leader speeds are similar to downward -CG leader speeds. Our observations also show that the speeds tend to increase by a factor of 1.1 to 6.5 as they approach the ground. The presence of short duration, recoil leaders (RLs) during the development of positive leaders reveal a highly branched structure that is not usually recorded when using conventional photographic and video cameras. The existence of the RLs may help to explain observations of UHF-VHF radiation during the development of +CG flashes.

A method for plotting the complementary root locus using the root-locus (positive gain) rules

The root-locus method is a well-known and commonly used tool in control system analysis and design. It is an important topic in introductory undergraduate engineering control disciplines. Although complementary root locus (plant with negative gain) is not as common as root locus (plant with positive gain) and in many introductory textbooks for control systems is not presented, it has been shown a valuable tool in control system design. This paper shows that complementary root locus can be plotted using only the well-known construction rules to plot root locus. It can offer for the students a better comprehension on this subject. These results present a procedure to avoid problems that appear in root-locus plots for plants with the same number of poles and zeros.

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.

LMI-based algorithm for strictly positive real systems with static output feedback

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

Positive end-expiratory pressure in acute respiratory distress syndrome: should the 'open lung strategy' be replaced by a 'protective lung strategy'?

In patients with acute respiratory distress syndrome, positive end-expiratory pressure is associated with alveolar recruitment and lung hyperinflation despite the administration of a low tidal volume. The best positive end-expiratory pressure should correspond to the best compromise between recruitment and distension, a condition that coincides with the best respiratory elastance.

Different nutritional-state indicators of HIV-positive individuals undergoing antiretroviral therapy

This study aimed at learning about the nutritional profile of HIV-positive individuals undergoing antiretroviral therapy and at comparing the performance of nutritional-state indicators. A transversal study was performed on 94 patients attending the Tropical Diseases Outpatient Hospital of Botucatu Medical School (FMB)-UNESP. The body mass index (BMI) and the classification by Papini-Berto (PB) were used to evaluate nutritional state, aiming at detecting malnutrition and obesity. The waist-to-hips ratio (W/HR) and waist circumference (WC) were adopted for identification of abdominal obesity and lipodystrophy. According to BMI, most of the individuals were eutrophic, followed by 30.9% overweight and 6.4% malnourished. By using the PB classification, the frequency of malnourished increased (22.3%). The analysis of the PB classification in relation to BMI indicated that the former presented high sensitivity and good specificity for malnutrition diagnosis, namely 100% and 83%, respectively. The prevalence of abdominal obesity was 7.44% according to WC, and a higher prevalence (38.3%) was observed when taking W/HR into account. There was significant positive association between nutritional diagnosis according to PB and T CD4(+) lymphocyte. The results support the use of PB classification for malnutrition detection as well as that of BMI and W/HR for overweight and fat redistribution.

Effect of soluble fiber on hypertriglyceridemia and immune profile in HIV-positive individuals undergoing highly active antiretroviral therapy

The advent of highly active antiretroviral therapy (HAART), since 1996, represented a profound impact on the natural history of HIV-infection by promoting important and sustainable viral replication suppression and increasing survival and quality of life among seropositive patients. Nonetheless, antiretroviral therapy has been observed to be accompanied by metabolic alterations such as dyslipidemia, especially hypertriglyceridemia, insulin resistance, hyperglycemia and lipodystrophy (body fat redistribution). Epidemiological studies have demonstrated a correlation between high triglyceride (TG) levels and higher incidence of coronary artery disease (CAD). Some investigators suggest dietary intervention as part of hyperlipidemia treatment, including an increase in soluble fiber intake (10-25g/day). Whereas some studies have demonstrated that both cholesterol and serum triglyceride levels decrease with the use of food fiber, others have shown just a serum triglyceride decrease, and others failed to observe any alteration in lipid metabolism. The purpose of this study was to assess the effect of soluble fiber (R) (partially hydrolyzed guar gum) supplementation on hypertriglyceridemia and immune profile in HIVpositive individuals on HAART. Nineteen HIV-positive individuals with hypertriglyceridemia (serum levels >= 150 to < 500mg/dl) were studied. of these individuals, 63.16% were males and 36.84% females, with mean age of 43.52 +/- 9.22 years. These individuals had been on the same HAART regimen for at least six months, had no change in therapy during the study and received 20g/day of soluble fiber for four months at pre-established times. Clinical-nutritional, biochemical (total proteins, albumin, globulin, total cholesterol, LDL-c, HDL-c, TG, TG/HDL-c and LDLc/HDL-c), hematimetric (hemoglobin, hematocrit and total lymphocytes), and immunologic (lymphocytes T CD4(+), T CD8(+); T CD4(+)/CD8(+) ratio, viral load, TNF-alpha and IL-6) parameters were assessed in all patients at three time points (M0: pretreatment, M1: 30 days, and M2: four months after intervention). Significance level was set at 5% for all data statistically analyzed. Serum TG and TG/HDL-c ratio reduction was observed at all time points, but statistical significance was found just at M0 and M2. The remaining biochemical, hematimetric and immunologic parameters (lymphocytes T CD4(+), T CD8(+); T CD4(+)/ CD8(+) ratio, and viral load) showed no significant difference at all times. Regarding serum cytokines, TNF-alpha and IL-6 significantly decreased between M0 and M2, and only IL-6 reduced between M1 and M2. The data collected show that dietary and anthropometric parameters remained unchanged excluding potential confounding factors related with the effect of fiber supplementation on serum TG, TNF-alpha and IL-6. Thus, soluble fiber (R) contributed to an important reduction in hypertriglyceridemia and in the serum levels of the proinflammatory cytokines TNF-alpha and IL-6 in HIV-seropositive individuals on HAART. In addition, soluble fiber (R) might have minimized the process of atherosclerosis in these individuals, given that elevated serum levels of TG, TNF-alpha and IL-6 have been associated with the development of these lesions.

Adjuvant therapy with GnRH agonists/tamoxifen in breast cancer should be a good council for patients with hormone receptor-positive tumours and wish to preserve fertility

Infertility represents one of the main long-term consequences of the chemotherapy used for the adjuvant treatment of breast cancer. Approximately 60-65% of breast cancers express the nuclear hormone receptor in premenopausal women. Adjuvant endocrine therapy is an integral component of care for patients with hormone receptor-positive (HR+) tumours. The GnRH agonist (GnRHa) alone or in combination with tamoxifen produces results at least similar to those obtained with the different chemotherapy protocols in patients with HR+ breast cancer with respect to recurrence-free survival and overall survival. It is time to indicate adjuvant therapy with GnRHa associated with tamoxifen for patients with breast cancer (HR+ tumours) if they want to preserve their reproductive function. The evaluation of ovarian reserve tests: follicle stimulating hormone (FSH), anti-Mullerian hormone (AMH), inhibin B, antral follicle count (AFC) and ovarian volume 6 months, and 1 year after the end of therapy with GnRHa/tamoxifen must be realised. The recurrence-free survival and overall survival should be analysed. The major implication of this hypothesis will be to avoid adjuvant chemotherapy for patients with breast cancer (HR+ tumours) that request fertility preservation. It is expected that ovarian function should not be altered in almost all cases and subsequent pregnancy a real possibility. (C) 2012 Elsevier Ltd. All rights reserved.