Lighting conditions and optical filters effects on visual performance of speleologists exposed to cave environments

The aim of this study is to evaluate lighting conditions and speleologists’ visual performance using optical filters when exposed to the lighting conditions of cave environments. A crosssectional study was conducted. Twenty-three speleologists were submitted to an evaluation of visual function in a clinical lab. An examination of visual acuity, contrast sensitivity, stereoacuity and flashlight illuminance levels was also performed in 16 of the 23 speleologists at two caves deprived of natural lightning. Two organic filters (450 nm and 550 nm) were used to compare visual function with and without filters. The mean age of the speleologists was 40.65 (± 10.93) years. We detected 26.1% participants with visual impairment of which refractive error (17.4%) was the major cause. In the cave environment the majority of the speleologists used a head flashlight with a mean illuminance of 451.0 ± 305.7 lux. Binocular visual acuity (BVA) was -0.05 ± 0.15 LogMAR (20/18). BVA for distance without filter was not statistically different from BVA with 550 nm or 450 nm filters (p = 0.093). Significant improved contrast sensitivity was observed with 450 nm filters for 6 cpd (p = 0.034) and 18 cpd (p = 0.026) spatial frequencies. There were no signs and symptoms of visual pathologies related to cave exposure. Illuminance levels were adequate to the majority of the activities performed. The enhancement in contrast sensitivity with filters could potentially improve tasks related with the activities performed in the cave.

A study on parallel versus sequential relational fuzzy clustering methods

Dissertação para obtenção do Grau de Mestre em Engenharia Informática

Separating sequential equilibrium in a Bayesian international duopoly

We consider two Cournot firms, one located in the home country and the other in the foreign country, producing substitute goods for consumption in a third country. We suppose that neither the home government nor the foreign firm know the costs of the home firm, while the foreign firm cost is common knowledge. We determine the separating sequential equilibrium outputs.

Two sequential PCR amplifications for detection of Schistosoma mansoni in stool samples with low parasite load

Schistosomiasis constitutes a major public health problem, with an estimated 200 million individuals infected worldwide and 700 million people living in risk areas. In Brazil there are areas of high, medium and low endemicity. Studies have shown that in endemic areas with a low prevalence of Schistosoma infection the sensitivity of parasitological methods is clearly reduced. Consequently diagnosis is often impeded due to the presence of false-negative results. The aim of this study is to present the PCR reamplification (Re-PCR) protocol for the detection of Schistosoma mansoni in samples with low parasite load (with less than 100 eggs per gram (epg) of feces). Three methods were used for the lysis of the envelopes of the S. mansoni eggs and two techniques of DNA extraction were carried out. Extracted DNA was quantified, and the results suggested that the extraction technique, which mixed glass beads with a guanidine isothiocyanate/phenol/chloroform (GT) solution, produced good results. PCR reamplification was conducted and detection sensitivity was found to be five eggs per 500 mg of artificially marked feces. The results achieved using these methods suggest that they are potentially viable for the detection of Schistosoma infection with low parasite load.

Design of switched-capacitor filters using low gain amplifiers

Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores

Heavy metals removal in dual media filters

Dissertação para obtenção do Grau de Mestre em Engenharia do Ambiente – Perfil de Engenharia Sanitária

Removal of Trypanosoma cruzi by white cell-reduction filters: an electronmicroscopic study

White cell (WBC)-reduction filters have been shown to be effective in removing infectious agents from infected blood products. In this study, the mechanisms of Trypanosoma cruzi (T. cruzi) retention by WBC-reduction filters were assessed. Human packed red blood cell (PRBC) and platelet concentrate (PC) samples were contaminated with T. cruzi organisms (Y strain; 3.4 x 10(6)/ml), and then filtered using WBC-reduction experimental filters that provided about 3 log10 WBC removal. Transmission electron microscopy sections showed that T. cruzi parasites were removed from contaminated PRBC and PC samples primarily by mechanical mechanism without interacting with filter fibbers or blood cells. In addition, we found that T. cruzi parasites were also removed by a direct fibber adhesion. These data indicate that T. cruzi parasites are removed from infected blood not only by mechanical mechanism but also by biological mechanism probably mediated by parasite surface proteins.

Tool for discovering sequential patterns in financial markets

The goal of this thesis is the study of a tool that can help analysts in finding sequential patterns. This tool will have a focus on financial markets. A study will be made on how new and relevant knowledge can be mined from real life information, potentially giving investors, market analysts, and economists new basis to make informed decisions. The Ramex Forum algorithm will be used as a basis for the tool, due to its ability to find sequential patterns in financial data. So that it further adapts to the needs of the thesis, a study of relevant improvements to the algorithm will be made. Another important aspect of this algorithm is the way that it displays the patterns found, even with good results it is difficult to find relevant patterns among all the studied samples without a proper result visualization component. As such, different combinations of parameterizations and ways to visualize data will be evaluated and their influence in the analysis of those patterns will be discussed. In order to properly evaluate the utility of this tool, case studies will be performed as a final test. Real information will be used to produce results and those will be evaluated in regards to their accuracy, interest, and relevance.

Impact of an intervention in the use of sequential antibiotic therapy in a Brazilian university hospital

INTRODUCTION: Sequential antibiotic therapy (SAT) is safe and economical. However, the unnecessary use of intravenous (IV) administration usually occurs. The objective of this work was to get to know the effectiveness of an intervention to implement the SAT in a teaching hospital in Brazil. METHODS: This was a prospective and interventional study, historically controlled, and was conducted in the Hospital de Clínicas, Universidade Federal de Uberlândia, State of Minas Gerais, Brazil, a high complexity teaching hospital having 503 beds. In each of the periods, from 04/04/05 to 07/20/05 (pre-intervention) and from 09/24/07 to 12/20/07 (intervention), 117 patients were evaluated. After the pre-intervention period, guidelines were developed which were implemented during the intervention period along with educational measures and a reminder system added to the patients' prescription. RESULTS: In the pre-intervention and intervention periods, the IV antibiotics were used as treatment for a average time of 14.8 and 11.8 days, respectively. Ceftriaxone was the antibiotic most prescribed in both periods (23.4% and 21.6% respectively). Starting from the first prescription of antibiotics, the average length of hospitalization time was 21.8 and 17.5 days, respectively. The SAT occurred only in 4 and 5 courses of treatment, respectively, and 12.8% and 18.8% of the patients died in the respective periods. CONCLUSIONS: Under the presented conditions, the evaluated intervention strategy is ineffective in promoting the exchange of the antibiotic administration from IV to oral treatment (SAT).

Prevention in underground construction with sequential excavation method

This paper aims to describe the Sequential Excavation Method, used for excava-tion in underground works, as well as the related risks and preventive measures. This method has characteristics that differentiate it from other tunnelling techniques: it uses a larger number of workers and equipment; it has a high concurrency of tasks with various workers and equip-ment quite exposed to hazards; and it uses many potentially aggressive chemicals. Firstly, it is given a broad overview of this issue. Afterwards, it will be presented the results of a survey to a sample of experienced technicians, aimed at gauging the relevance of a set of guidelines relat-ing to the design and work phases, applicable to the domestic market and prepared following technical visits to works abroad.

Implementation and comparison of different switching techniques for shunt active power filters

This paper presents a comparison between three switching techniques that can be used in three-phase four-wire Shunt Active Power Filters (SAPFs). The implemented switching techniques are: Periodic-Sampling (PS), Triangular Carrier Pulse-Width Modulation (TC-PWM) and Space Vector PWM (SVPWM). The comparison between them is made in terms of the compensated currents THD%, implementation complexity, necessary CPU time and SAPF efficiency. To perform this comparison are presented and analyzed several experimental results, obtained with a 20 kVA Shunt Active Power Filter prototype, specially developed for this purpose. The control system of the developed SAPF is based in the p-q Theory with a grid synchronization algorithm p-PLL.

Design and development of high gain wideband microstrip antenna and DGS filters using numerical experimentation approach

Microstrip antenna, Wideband antennas, high gain antennas, Microstrip filters, DGS filters , low-pass filter, band-pass filter

Design, modeling and fabrication of radio-frequency microelectromechanical switches and coplanar filters

Magdeburg, Univ., Fak. für Elektrotechnik und Informationstechnik, Diss., 2010

Analysis, design, optimization and realization of compact high performance printed RF filters

Magdeburg, Univ., Fak. für Elektrotechnik und Informationstechnik, Diss., 2010