CATHODIC BEHAVIOUR of ANODIZED TITANIUM IN SIMULATED PHYSIOLOGICAL CONDITIONS

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

South Atlantic Ocean cyclogenesis climatology simulated by regional climate model (RegCM3)

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

Generalized simulated annealing: Application to silicon clusters

We have compared the recently introduced generalized simulated annealing (GSA) with conventional simulated annealing (CSA). GSA was tested as a tool to obtain the ground-state geometry of molecules. We have used selected silicon clusters (Sin, n=4-7,10) as test cases. Total energies were calculated through tight-binding molecular dynamics. We have found that the replacement of Boltzmann statistics (CSA) by Tsallis's statistics (GSA) has the potential to speed up optimizations with no loss of accuracy. Next, we applied the GSA method to study the ground-state geometry of a 20-atom silicon cluster. We found an original geometry, apparently lower in energy than those previously described in the literature.

Combining genetic algorithm and simulated annealing: A molecular geometry optimization study

We introduce a new hybrid approach to determine the ground state geometry of molecular systems. Firstly, we compared the ability of genetic algorithm (GA) and simulated annealing (SA) to find the lowest energy geometry of silicon clusters with six and 10 atoms. This comparison showed that GA exhibits fast initial convergence, but its performance deteriorates as it approaches the desired global extreme. Interestingly, SA showed a complementary convergence pattern, in addition to high accuracy. Our new procedure combines selected features from GA and SA to achieve weak dependence on initial parameters, parallel search strategy, fast convergence and high accuracy. This hybrid algorithm outperforms GA and SA by one order of magnitude for small silicon clusters (Si6 and Si10). Next, we applied the hybrid method to study the geometry of a 20-atom silicon cluster. It was able to find an original geometry, apparently lower in energy than those previously described in literature. In principle, our procedure can be applied successfully to any molecular system. © 1998 Elsevier Science B.V.

Deposition and leaching of tebuthiuron on sugar cane straw applied with and without alkyl polyglycoside adjuvant

A laboratory experiment was carried out aiming to study the effects of an alkyl polyglycoside adjuvant (APG) on deposition and leaching of the herbicide tebuthiuron applied on sugar cane straw. Tebuthiuron, at concentration of 1200 mg L-1, was applied separately and in tank mix with the APG adjuvant, at concentrations of 0.07 and 0.09% (wt v-1), using a spraying volume of 204 L ha-1. A precipitation equivalent to 20 mm of rain was simulated, 24 h after the applications, to evaluate the herbicide leaching. The quantification of tebuthiuron was carried out by the high performance liquid chromatography (HPLC). It was observed that the addition of APG adjuvant at 0.07% (wt v-1) provided an increase of 11.5% in the deposition of tebuthiuron on straw, reduction of 50.4% in the drift of the herbicide and it did not affect significantly the leached amount (68.5%), when compared with the treatment where tebuthiuron was applied alone (70.8%). At the concentration of 0.09% (wt v-1), the APG adjuvant caused an increase of 22.7% in the deposition; it reduced the drift of the herbicide by 99.9% and reduced the leached amount by 7.6% thereby increasing the retention of the herbicide by straw.

A administração precoce de hormônio de crescimento resulta em efeitos deletérios na remodelação ventricular após o infarto agudo do miocárdio

Objective: To assess the effect of growth hormone (GH) on myocardial remodeling in infarcted rats. Methods: This study comprised 24 Wistar rats divided into 3 groups as follows: 1) AMI-GH group - comprising 8 rats that underwent infarction and were treated with GH; 2) AMI group - comprising 8 rats that underwent infarction and received only the diluent of the GH solution; and 3) control group (C group) - comprising 8 rats that underwent simulated infarction. After 30 days, the animals underwent functional study through echocardiography, and the changes in myocardial contractility of the isolated left ventricular (LV) papillary muscle were studied. Results: The echocardiography identified an increase in the diastolic (C=7.32±0.49; AMI=8.50±0.73; AMI-GH=9.34±0.73; P<0.05) and systolic (C=3.38±0.47, AMI=5.16±1.24; AMI-GH=5.96±1.54; P<0.05) diameters (mm) in the LV of the infarcted animals. The AMI-GH group animals had a lower ejection fraction (%) (C=0.9±0.03; AMI=0.76±0.12; AMI-GH=0.72± 0.14; P<0.05 for C vs AMI-GH) compared with those in controls. The study of the isolated left ventricular papillary muscle showed that the AMI-GH group had changes (C=1.50±0.59; AMI= 1.28±0.38; AMI-GH=1.98±0.41; P<0.05 for C vs AMI-GH) only in the tension at rest (TR - g/mm2) and in the time delta for a 50% decrease in the tension developed (TR50, ms) after stimulation with calcium (C=23.75±9.16; AMI=-16.56±14.82; AMI-GH=-4.69±8.39; P<0.05 for C vs AMI-GH) and in the delta of tension developed (TD, g/mm2) after stimulation with isoproterenol (C=0.99±0.17; AMI=0.54±0.62; AMI-GH=0.08±0.75; P<0.05 for C vs AMI-GH) compared with those in control animals. Conclusion: The early administration of GH in the experimental infarction model in rats may result in adverse effects on the process of ventricular remodeling.

Potassium leaching from millet straw as affected by rainfall and potassium rates

Pearl millet (Penisetum glaucum) is an interesting species to be used as cover crop in tropical areas, showing a high ability in potassium uptake. Potassium (K) is not linked to organic compounds in the plant, and can easily be released from decaying straw becoming available for subsequent crops. This experiment evaluated K leaching from millet straw grown under potassium rates (0, 100, 200, and 300 mg dm-3), and submitted to five levels of simulated rain (5, 10, 20, 40, and 80 mm). Plants were grown in soil filled pots in a greenhouse. On the 50th day after emergence, the plants were desiccated with glyphosate. Artificial rain was applied over the straw. Potassium deficiency speeds up millet dehydration after herbicide application and increases lightly rain water retention in the straw. The amount of K leached right after plant desiccation is correlated with the residue nutrient content and can be as high as 64 kg ha-1 considering a mulch of 8 t ha -1. Although well-nourished millet plants release considerable amounts of K with the first rains, a large percentage of the nutrient is still retained in the straw. Copyright © Taylor & Francis, Inc.

A framework for learning in humanoid simulated robots

One of the most important characteristics of intelligent activity is the ability to change behaviour according to many forms of feedback. Through learning an agent can interact with its environment to improve its performance over time. However, most of the techniques known that involves learning are time expensive, i.e., once the agent is supposed to learn over time by experimentation, the task has to be executed many times. Hence, high fidelity simulators can save a lot of time. In this context, this paper describes the framework designed to allow a team of real RoboNova-I humanoids robots to be simulated under USARSim environment. Details about the complete process of modeling and programming the robot are given, as well as the learning methodology proposed to improve robot's performance. Due to the use of a high fidelity model, the learning algorithms can be widely explored in simulation before adapted to real robots. © 2008 Springer-Verlag Berlin Heidelberg.

Efeito da chuva sobre a ação do herbicida imazapyr no controle de plantas daninhas aquáticas

The aim of this study was to evaluate the influence of different periods of rainfall that occurred after the application of the imazapyr herbicide on the control efficiency of Pistia stratiotes and Eichhornia crassipes. We studied 10 mm rainfall, applied for 5' at different time periods (0h, 2h, 4h, 6h, 8h, 12h, 24h, not simulated rainfall) after the application of imazapyr formulation Arsenal NA, 250 g ai ha -1 (1.0 L cp ha -1). The experiment had completely randomized design with four replications. Plants were evaluated at 7, 14, 21, 28 and 35 days after application (DAA), and the results submitted to analysis of variance by F test and treatment means compared by Tukey's test (p <0. 05). The occurrence of rainfall up to 6 hours after herbicide application, plants of P. stratiotes, negatively affected its efficiency and control; rainfall intervals over 8 hours had no effect in control. The occurrence of rainfall at all time intervals did not affect the control of E. crassipes plants.

Commissioning of the CMS experiment and the cosmic run at four tesla

The CMS Collaboration conducted a month-long data-taking exercise known as the Cosmic Run At Four Tesla in late 2008 in order to complete the commissioning of the experiment for extended operation. The operational lessons resulting from this exercise were addressed in the subsequent shutdown to better prepare CMS for LHC beams in 2009. The cosmic data collected have been invaluable to study the performance of the detectors, to commission the alignment and calibration techniques, and to make several cosmic ray measurements. The experimental setup, conditions, and principal achievements from this data-taking exercise are described along with a review of the preceding integration activities. © 2010 IOP Publishing Ltd and SISSA.

ASTER: A Brazilian mission to an asteroid

The first Brazilian mission to an asteroid is being planned. The target is the asteroid 2001 SN263, which has a NEA orbit of class AMOR. Spectral analysis indicated that this is a C-type asteroid. This type of asteroids are dark and difficult to be studied from Earth. They hold clues of the initial stages of planetary formation and also the origin of water and life on Earth. In fact, radar data showed that 2001 SN263 is composed of three bodies with diameters of about 2.8 km, 1.1 km and 0.4 km. Therefore, the spacecraft will have the opportunity to explore three bodies on the same trip. The mission is scheduled to be launched in 2015, reaching the asteroid in 2018. It will be used a small spacecraft (150 kg) with 30 kg for the payload. The set of scientific instruments being considered to explore the target of this mission include an Imaging Camera, a Laser Rangefinder, an Infrared Spectrometer, a Synthetic Aperture Radar and a Mass Spectrometer. The main measurements to be made include the bulk properties (size, shape, mass, density, dynamics, spin state), the internal properties (structure, gravity field) and surface properties (mineralogy, morphology, elemental composition). The mission also opens an opportunity for some relevant experiments, not directly related to the target. Two such experiments will take benefit from being on board of the spacecraft along the journey to the asteroid system, which will take about three years. The first is an astrobiology experiment. The main goal of this experiment is to determine the viability of the microorganisms survival in extraterrestrial environments simulated in laboratory (chemical atmosphere, temperature, desiccation, vacuum, microgravity and radiation). The second experiment is a plasma package. The main objectives of this experiment are to study the structure and electrodynamics of plasma along the trajectory, the plasma instability processes and the density and temperature of plasma of solar wind origin along the trajectory and near the asteroids. This mission represents a great challenge for the Brazilian space program. It is being structured to allow the full engagement of the Brazilian universities and technological companies in all the necessary developments to be carried out. In this paper, we present some aspects of this mission and details of the payload that will be used and the scientific expectations. Copyright ©2010 by the International Astronautical Federation. All rights reserved.

Self-optimization of dense wireless sensor networks based on simulated annealing

Wireless sensor network (WSN) Is a technology that can be used to monitor and actuate on environments in a non-intrusive way. The main difference from WSN and traditional sensor networks is the low dependability of WSN nodes. In this way, WSN solutions are based on a huge number of cheap tiny nodes that can present faults in hardware, software and wireless communication. The deployment of hundreds of nodes can overcome the low dependability of individual nodes, however this strategy introduces a lot of challenges regarding network management, real-time requirements and self-optimization. In this paper we present a simulated annealing approach that self-optimize large scale WSN. Simulation results indicate that our approach can achieve self-optimization characteristics in a dynamic WSN. © 2012 IEEE.

Remote laboratory experiment access via an RFID interface

In this paper, remote laboratory experiment access is considered through the use of radio frequency identification (RFID) technology. Contactless smart cards are used widely in many applications from travel cards through to building access control and inventory tracking. However, their use is considered here for access to electronic engineering experimentation in a remote laboratory setting by providing the ability to interface experiments through this contactless (wireless) connection means. A case study design is implemented to demonstrate such a means by incorporating experiment data onto a contactless smart card and accessing this via a card reader and web server arrangement. © 2012 IEEE.

Teaching and learning data structures supported by computers: An experiment using CADILAG tool

This paper aims to present the use of a learning object (CADILAG), developed to facilitate understanding data structure operations by using visual presentations and animations. The CADILAG allows visualizing the behavior of algorithms usually discussed during Computer Science and Information System courses. For each data structure it is possible visualizing its content and its operation dynamically. Its use was evaluated an the results are presented. © 2012 AISTI.