Papers by Rafael Figueiredo
The aim of this paper is to present the Power Electronics Laboratory -LABEP from the Polytechni... more The aim of this paper is to present the Power Electronics Laboratory -LABEP from the Polytechnic Institute of Pontificia Universidade Catolica de Minas Gerais -PUC Minas -Brazil, focusing on the Electronics Design Automation -EDA tools uses in the laboratory for development of practical courses and research projects. First, it presents the hardware and software infrastructure available. To exemplify the development of practical classes using the infrastructure, it presents a step by step procedure for the study of the triphase thyristors inverter. The results of the procedure are presented and analyzed.
Based on a diode-laser model, this paper presents the equivalent electrical circuit above and bel... more Based on a diode-laser model, this paper presents the equivalent electrical circuit above and below the transparency condition for a chip (unpackaged) semiconductor optical amplifier. The modeling and parameters extraction were obtained as a function of the bias current, achieving good agreement between theoretical and experimental results in a wide frequency range, up to 40 GHz.
Remote applications are becoming widely used in various fields such as industry, education, and s... more Remote applications are becoming widely used in various fields such as industry, education, and security. This paper presents a low cost system to monitor and control laboratory instruments remotely by Short Message Service (SMS). The system has been designed using the National Instruments Laboratory Virtual Instrument Engineering Workbench (LabVIEW) development system. The user sends commands using a mobile phone remotely connected to a modem. The software recognizes the received code and transmits the command to the instrument. The system was successfully tested locally and remotely in a signal measurement procedure.
A 2-year community-randomized controlled trial of fluoride varnish to prevent early childhood caries in Aboriginal children
Community Dentistry and Oral Epidemiology, 2008
Abstract – Objective: To measure the effectiveness of fluoride varnish (FV) (Duraflor®, 5% sodi... more Abstract – Objective: To measure the effectiveness of fluoride varnish (FV) (Duraflor®, 5% sodium fluoride, Pharmascience Inc., Montréal, QC, Canada) and caregiver counseling in preventing early childhood caries (ECC) in Aboriginal children in a 2-year community-randomized controlled trial.Methods: Twenty First Nations communities in the Sioux Lookout Zone (SLZ), Northwest Ontario, Canada were randomized to two study groups. All caregivers received oral health counseling, while children in one group received FV twice per year and the controls received no varnish. A total of 1275, 6 months to 5-year-old children from the SLZ communities were enrolled. In addition, a convenience sample of 150 primarily non-Aboriginal children of the same age were recruited from the neighboring community of Thunder Bay and used as comparisons. Longitudinal examinations for the dmft/s indices were conducted by calibrated hygienists in 2003, 2004 and 2005.Results: Aboriginal children living in the SLZ or in Thunder Bay had significantly higher caries prevalence and severity than non-Aboriginal children in Thunder Bay. FV treatment conferred an 18% reduction in the 2-year mean ‘net’ dmfs increment for Aboriginal children and a 25% reduction for all children, using cluster analysis to adjust for the intra-cluster correlation among children in the same community. Adjusted odds ratio for caries incidence was 1.96 times higher in the controls than in the FV group (95% CI = 1.08–3.56; P = 0.027). For those caries-free at baseline, the number (of children) needed to treat (NNT) equaled 7.4.Conclusions: Findings support the use of FV at least twice per year, in conjunction with caregiver counseling, to prevent ECC, reduce caries increment and oral health inequalities between young Aboriginal and non-Aboriginal children.
Community Dentistry and Oral Epidemiology, 2009
Abstract – Objectives: To investigate (i) oral health inequalities between off-reserve Aborigin... more Abstract – Objectives: To investigate (i) oral health inequalities between off-reserve Aboriginal and non-Aboriginal children entering junior kindergarten (JK) in the Thunder Bay District, Northwest Ontario, Canada, (ii) oral health inequalities between kindergarten-aged (4 years old) Aboriginal children living on reserves in the Sioux Lookout Zone (SLZ), Northwest Ontario and those living off-reserve in the Thunder Bay District and (iii) early childhood caries (ECC) trends among SLZ children between 2001 and 2005.Methods: Cross-sectional oral health data (dmft/s Indices) for 416 (2003/2004), 687 (2004/2005) and 544 (2005/2006) 3- to 5-year olds attending JK in the Thunder Bay District were collected by calibrated dental hygienists with the District’s Health Unit. Secondary analysis of oral health status data from two studies conducted in the SLZ between 2001 and 2005 provided the dmft of random samples of children younger than 6 years of age living in 16–20 First Nations communities.Results: When compared with non-Aboriginal children aged 3–5 years attending the same schools in the Thunder Bay District between 2003 and 2006, off-reserve Aboriginal children had 1.9 to 2.3 times the risk of having ECC (dmft > 0), 2.9 to 3.5 times the risk of a dmft > 3 and 1.8 to 2.5 times the risk of untreated decayed teeth after adjusting the prevalence ratios for child’s age and sex, school’s risk level and clustered-correlated data. The mean dmft of on-reserve Aboriginal 4-year olds in 2005 was 11.2 and 5.9 for their off-reserve Aboriginal counterparts. In 2001, the mean dmft scores (95% confidence interval) of 2-, 3- and 4-year-old Aboriginal children in the SLZ were: 9.1 (8.3–9.9), 12.4 (11.8–13.1), 13.1 (12.1–14.2). In 2005, similarly aged SLZ children had a mean dmft of: 6.2 (5.2–7.1), 8.9 (8.2–9.6), 11.2 (10.5–11.9), representing significant reductions in caries severity (32%, 28% and 14.5%, respectively).Conclusions: Significant disparities in caries experience exist between off-reserve Aboriginal and non-Aboriginal children living in the same locales and between Aboriginal children living on- and off-reserve in northwestern Ontario. The study showed decreased trends in the severity of ECC for children in the SLZ occurring over the 5-year period. Despite this progress, the oral health of young Aboriginal children in Ontario continues to lag far behind that of non-Aboriginal children, demanding further programs and policies to tackle the social determinants of oral health and resolve these inequalities.
Community Dentistry and Oral Epidemiology, 2009
Objectives: This study explored oral health disparities associated with food insecurity in worki... more Objectives: This study explored oral health disparities associated with food insecurity in working poor Canadians.Methods: We used a cross-sectional stratified study design and telephone survey methodology to obtain data from 1049 working poor persons aged between 18 and 64 years. The survey instrument contained sociodemographic items, self-reported oral health measures, access to dental care indicators (dental visiting behaviour and insurance coverage) and questions about competing financial demands. Food-insecure persons gave ‘often’ or ‘sometimes’ responses to any of the three food insecurity indicators used in the Canadian Community Health Survey (2003) assessing ‘worry’ about not having enough food, not eating enough food and not having the desired quality of food because of insufficient finances in the previous 12 months.Results: Food-insecure working poor persons had poor oral health compared with food-secure working poor persons indicated by a higher percentage of denture wearers (P < 0.001) and a higher prevalence of toothache, pain and functional impacts related to chewing, speaking, sleeping and work difficulties (P < 0.001). Fewer food-insecure persons rated their oral health as good or very good (P < 0.001). Logistic regression analyses showed that oral health disparities between food-insecure and food-secure persons related to denture wearing, having a toothache, reporting poor/very poor self-rated oral health or experiencing an oral health impact persisted after adjusting for sociodemographic factors and access to dental care factors (P < 0.05). Food-insecure working poor persons reported relinquishing goods or services in order to pay for necessary dental care.Conclusions: This study identified oral health disparities within an already marginalized group not alleviated by access to professional dental care. Working poor persons regarded professional dental care as a competing financial demand.
Community Dentistry and Oral Epidemiology, 2010
Quiñonez C, Figueiredo R, Azarpazhooh A, Locker D. Public preferences for seeking publicly financ... more Quiñonez C, Figueiredo R, Azarpazhooh A, Locker D. Public preferences for seeking publicly financed dental care and professional preferences for structuring it. Community Dent Oral Epidemiol 2010. © 2010 John Wiley & Sons A/SAbstract – Objectives: To test the hypotheses that socially marginalised Canadians are more likely to prefer seeking dental care in a public rather than private setting, and that Canadian dentists are more likely to prefer public dental care plans that approximate private insurance processes.Methods: Data on public opinion were collected through a weekly national omnibus survey based on random digit dialling and telephone interview technology (n = 1005, >18 years). Data on professional opinion were collected through a national mail-out survey of a random selection of Canadian dentists (n = 2219, response rate = 45.8%). Dental and socio-demographic data were collected for the public, as were professional demographic data for dentists. Descriptive and basic regression analyses were undertaken.Results: The majority of Canadians surveyed, 66.4%, prefer to seek dental care in a private setting, 19% in a community clinic, and 7.6% in a dental school; those that are younger and of lowest incomes are most likely to prefer seeking dental care in a public setting. Most Canadian dentists, 80.9%, believe that governments should be involved in dental care, yet only 46% believe this role should include direct delivery. A third of dentists have also reduced the amount of publicly insured patients in their practice. Canadian dentists are more likely to prefer those public plans that most closely reflect private insurance mechanisms.Conclusion: There appears to be a policy disconnect between the preferences of those populations where governmental involvement is most warranted, and the current mechanisms for financing and delivering dental care in Canada. By concentrating almost exclusively on third-party-type financing and indirect delivery, public dental care policy may not be adequately responding to those most in need, especially in an environment where dentists are largely dissatisfied with public plans.
Disability days in Canada associated with dental problems: a pilot study
International Journal of Dental Hygiene, 2010
To cite this article: Int J Dent Hygiene9, 2011; 132–135 DOI: 10.1111/j.1601-5037.2010.00463.x Qu... more To cite this article: Int J Dent Hygiene9, 2011; 132–135 DOI: 10.1111/j.1601-5037.2010.00463.x Quiñonez C, Figueiredo R, Locker D. Disability days in Canada associated with dental problems: a pilot study.Abstract: Objective: The aim of this study was to explore disability days, or bed days and cut-down days, associated with dental problems in Canada. Methods: Data were collected through a national telephone interview survey of 1005 Canadians aged 18 years and over using random digit dialling. Participants were asked to enumerate the number of disability days associated with dental problems in the previous 2-week period. Descriptive and bivariate logistic regression analyses were undertaken. Results: In the previous 2-week period, 33 people, or 3.3% of the sample, reported spending a day in bed because of a dental problem. Of these, 22 people also reported having to cut down on their normal activity because of the dental problem. It appears that younger age groups, those with the lowest incomes, college educations, no dental insurance, oral pain and a history of visiting a hospital emergency room for a dental problem, were all more likely to report a dental disability day. Conclusions: These data demonstrate the potential economic impacts of dental problems in Canada, yet they must be interpreted with caution because of the very low prevalence of the main outcome measure, the potential for selection bias and the relative inconsistency with existing historical estimates.
Predictors of dental care utilization among working poor Canadians
Community Dentistry and Oral Epidemiology, 2009
Abstract – Objective: This study used the Gelberg–Andersen Behavioral Model for Vulnerable Popu... more Abstract – Objective: This study used the Gelberg–Andersen Behavioral Model for Vulnerable Populations to identify predictors of dental care utilization by working poor Canadians.Methods: A cross-sectional stratified sampling study design and telephone survey methodology was used to collect data from a nationally representative sample of 1049 working poor individuals aged 18 to 64 years. Working poor persons worked ≥20 h a week, were not full-time students and had annual family incomes <$34 300. A pretested questionnaire included sociodemographic items, self-reported oral health measures and two dental care utilization outcomes: time since their last dental visit and the usual reason for dental visits.Results: Hierarchical stepwise logistic analyses identified independent predictors associated with visiting the dentist >1 year ago: male gender (OR = 1.63; P = 0.005), aged 25–34 years (OR = 2.05; P = 0.02), paying for dental care with cash or credit (OR = 2.31; P < 0.001), past welfare recipients (OR = 1.65; P = 0.03), <21 teeth (OR = 4.23; P < 0.001) and having a perceived need for dental treatment (OR=2.78; P < 0.001). Sacrificing goods or services to pay for dental treatment was associated with visiting the dentist within the past year. The predictors of visiting the dentist only when in pain/trouble were lone parent status (OR = 4.04; P < 0.001), immigrant status (OR = 1.72; P = 0.006), paying for dental care with cash or credit (OR = 2.71; P < 0.001), a history of an inability to afford dental care (OR = 1.62; P = 0.01), a satisfactory/poor/very poor self-rated oral health (OR = 2.10; P < 0.001), number of teeth <21 (OR = 2.58; P < 0.001) and having a perceived need for dental treatment (OR = 2.99; P < 0.001).Conclusions: This study identified predisposing and enabling vulnerabilities that jeopardize the dental care-seeking practices of working poor persons. Dental care utilization was associated with relinquishing spending on other goods and services, which suggests that dental care utilization is a competing financial demand for economically constrained adults.
Journal of Public Health Dentistry, 2009
Objective: The aim of this study was to inform policy leaders of the opinions of Canada's major d... more Objective: The aim of this study was to inform policy leaders of the opinions of Canada's major dental care service provider regarding publicly financed dental care. Methods: Using provincial/territorial dental regulatory authority listings, a 26-item questionnaire was sent to a representative sample of Canadian dentists (n = 2219, response rate = 45.8 percent). Descriptive statistics were produced, and bivariate and multivariate logistic regressions were conducted to assess what predicts dentists' responses. Results: Canadian dentists support governmental involvement in dental care, preferring investments in prevention to direct delivery. The majority of dentists have less than 10 percent of their practice represented by publicly insured patients, with a small minority having greater than 50 percent. The majority would accept new publicly insured patients, preferring fee for service remuneration. Dentists generally appear dissatisfied with public forms of third-party financing. Conclusions: Dentists prefer a targeted effort at meeting public needs and are influenced in their opinions largely in relation to ideology. In order to move forward, policy leaders will need to devote some attention to the influence and complexity of public and private tensions in dentistry. At the very least, public and private practitioners must come to appreciate each other's challenges and balance public and private expectations in public programming.
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Papers by Rafael Figueiredo