Aplicação de programação cônica de segunda ordem inteira mista para a alocação ótima de bancos de capacitores em sistemas de distribuição de energia elétrica radiais

This paper shows the development of a mixed integer second-order conic programming model to solve the allocation problem of fixed or switched capacitors banks in radial electrical distribution systems, with the aims to improve the voltage magnitude profile, reduce the active power losses and minimize the energy losses and investment costs. In the proposed model, the steadystate operation point of the radial distribution system is modeled through linear and second-order conic expressions. The use of second-order conic programming model guarantee convergence to optimality using existing optimization software. The test systems of 70, 136 and 202 nodes are used in order to show the accuracy of the mathematical model, as well as the efficiency of the proposed solution technique.Sociedad Argentina de Informática e Investigación Operativ

Heart rate variability under resting conditions in postmenopausal and young women

The aim of the present study was to compare the modulation of heart rate in a group of postmenopausal women to that of a group of young women under resting conditions on the basis of R-R interval variability. Ten healthy postmenopausal women (mean ± SD, 58.3 ± 6.8 years) and 10 healthy young women (mean ± SD, 21.6 ± 0.82 years) were submitted to a control resting electrocardiogram (ECG) in the supine and sitting positions over a period of 6 min. The ECG was obtained from a one-channel heart monitor at the CM5 lead and processed and stored using an analog to digital converter connected to a microcomputer. R-R intervals were calculated on a beat-to-beat basis from the ECG recording in real time using a signal-processing software. Heart rate variability (HRV) was expressed as standard deviation (RMSM) and mean square root (RMSSD). In the supine position, the postmenopausal group showed significantly lower (P<0.05) median values of RMSM (34.9) and RMSSD (22.32) than the young group (RMSM: 62.11 and RMSSD: 49.1). The same occurred in the sitting position (RMSM: 33.0 and RMSSD: 18.9 compared to RMSM: 57.6 and RMSSD: 42.8 for the young group). These results indicate a decrease in parasympathetic modulation in postmenopausal women compared to young women which was possibly due both to the influence of age and hormonal factors. Thus, time domain HRV proved to be a noninvasive and sensitive method for the identification of changes in autonomic modulation of the sinus node in postmenopausal women

Raloxifene therapy does not affect uterine blood flow in postmenopausal women: a transvaginal Doppler study

AZEVEDO, George Dantas de et al. Raloxifene therapy does not affect uterine blood flow in postmenopausal women: a transvaginal Doppler study. Maturitas, Amsterdam, v.47, n.3, p.195-200, 2004Objective:To monitor the effects of raloxifene therapy on the uterus of postmenopausalwomen by transvaginal ultrasonography and color flow Doppler. Methods: Twenty-five healthy postmenopausal women were enrolled in this prospective longitudinal study performed at Department of Gynecology and Obstetrics, Faculty of Medicine of Ribeirão Preto. The patients were treated with raloxifene hydrochloride (60 mg per day) for 6 months. All were submitted to transvaginal ultrasound examination with color flow Doppler (ATL-HDI 3000 equipment) before the beginning and after 1, 3 and 6 months of treatment. Resistance index (RI) and pulsatility index (PI) of the uterine arteries were determined by the Doppler method, being considered as indicators of uterine perfusion. The following variables were analyzed: endometrial thickness, uterine volume, RI, and PI. Data were analyzed statistically by repeated-measures analysis of variance. Results: Before treatment, endometrial thickness was 3.38 ± 0.73 mm, and similar values were observed after 1, 3 and 6 months of treatment (3.04 ± 0.82; 3.3 ± 0.83; and 3.37 ± 0.79, respectively) (P > 0.05). No significant differences in uterine volume were observed between the pre- and post-treatment periods. Uterine artery perfusion as indicated by RI and PI measured by Doppler also showed no significant variation, with a high impedance flow being maintained throughout treatment. Conclusions: In the group studied here, raloxifene treatment at the dose of 60 mg per day for 6 months did not induce significant changes in endometrial thickness, uterine volume or uterine artery perfusion, confirming that short-term raloxifene treatment does not affect the uterus of postmenopausal wome

Tree diversity and above-ground biomass in the South America Cerrado biome and their conservation implications

Less than half of the original two million square kilometers of the Cerrado vegetation remains standing, and there are still many uncertainties as to how to conserve and prioritize remaining areas effectively. A key limitation is the continuing lack of geographically-extensive evaluation of ecosystem-level properties across the biome. Here we sought to address this gap by comparing the woody vegetation of the typical cerrado of the Cerrado–Amazonia Transition with that of the core area of the Cerrado in terms of both tree diversity and vegetation biomass. We used 21 one-hectare plots in the transition and 18 in the core to compare key structural parameters (tree height, basal area, and above-ground biomass), and diversity metrics between the regions. We also evaluated the effects of temperature and precipitation on biomass, as well as explored the species diversity versus biomass relationship. We found, for the first time, both that the typical cerrado at the transition holds substantially more biomass than at the core, and that higher temperature and greater precipitation can explain this difference. By contrast, plot-level alpha diversity was almost identical in the two regions. Finally, contrary to some theoretical expectations, we found no positive relationship between species diversity and biomass for the Cerrado woody vegetation. This has implications for the development of effective conservation measures, given that areas with high biomass and importance for the compensation of greenhouse gas emissions are often not those with the greatest diversity

Rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART): Study protocol for a randomized controlled trial

Background: Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality. Alveolar recruitment followed by ventilation at optimal titrated PEEP may reduce ventilator-induced lung injury and improve oxygenation in patients with ARDS, but the effects on mortality and other clinical outcomes remain unknown. This article reports the rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART). Methods/Design: ART is a pragmatic, multicenter, randomized (concealed), controlled trial, which aims to determine if maximum stepwise alveolar recruitment associated with PEEP titration is able to increase 28-day survival in patients with ARDS compared to conventional treatment (ARDSNet strategy). We will enroll adult patients with ARDS of less than 72 h duration. The intervention group will receive an alveolar recruitment maneuver, with stepwise increases of PEEP achieving 45 cmH(2)O and peak pressure of 60 cmH2O, followed by ventilation with optimal PEEP titrated according to the static compliance of the respiratory system. In the control group, mechanical ventilation will follow a conventional protocol (ARDSNet). In both groups, we will use controlled volume mode with low tidal volumes (4 to 6 mL/kg of predicted body weight) and targeting plateau pressure &lt;= 30 cmH2O. The primary outcome is 28-day survival, and the secondary outcomes are: length of ICU stay; length of hospital stay; pneumothorax requiring chest tube during first 7 days; barotrauma during first 7 days; mechanical ventilation-free days from days 1 to 28; ICU, in-hospital, and 6-month survival. ART is an event-guided trial planned to last until 520 events (deaths within 28 days) are observed. These events allow detection of a hazard ratio of 0.75, with 90% power and two-tailed type I error of 5%. All analysis will follow the intention-to-treat principle. Discussion: If the ART strategy with maximum recruitment and PEEP titration improves 28-day survival, this will represent a notable advance to the care of ARDS patients. Conversely, if the ART strategy is similar or inferior to the current evidence-based strategy (ARDSNet), this should also change current practice as many institutions routinely employ recruitment maneuvers and set PEEP levels according to some titration method.Hospital do Coracao (HCor) as part of the Program 'Hospitais de Excelencia a Servico do SUS (PROADI-SUS)'Brazilian Ministry of Healt