3,101 research outputs found
Transcultural adaptation of the who oral health questionnaire and its validation in chilean children
Indexación: Scopus.Introduction: The last edition of the WHO "Oral Health Questionnaire for Children" was published in 2013. This is an only-English version, and as such it requires linguistic adaptation and validation to be applied in the Chilean population. Objectives: To translate and adapt the WHO Oral Health Questionnaire for Children to Spanish and validate it in a Chilean population. Methods: A translation and back translation of the original instrument from English to Spanish was carried out by four translators. The questionnaire was self-reported as a pilot test in ten individuals. A sample was subsequently selected for convenience taking into account the population distribution, resulting in a final sample of 103 individuals. The internal consistency was calculated with Cronbach's alpha, criterion validity with Pearson's correlation coefficient and construct validity with Exploratory Factor Analysis. Results: A conceptual and semantic equivalence of the instrument was obtained. Women and men accounted for 43.69% and 56.31% of the sample, respectively. Cronbach's alpha coefficient was 0.62, while criterion validity was slightly positive between the total dimensions and the DMFT (r=0.13, p-value= 0.20). The Exploratory Factor Analysis yielded a total of 11 factors that explain 70% of the variability in the data. Conclusions: The oral health questionnaire has been appropriately adapted to Spanish, having conceptual as well as semantic equivalence to the original version, being reliable and valid to be used in a population of 12-year-old Chilean children. © 2018, Universidad de Concepcion. All rights reserved.http://joralres.com/index.php/JOR/article/view/432/43
Effect of Hysteresis on Measurements of Thin-Film Cell Performance
Transient or hysteresis effects in polycrystalline thin film CdS/CdTe cells are a function of pre-measurement voltage bias and whether Cu is introduced as an intentional dopant during back contact fabrication. When Cu is added, the current-density (J) vs. voltage (V) measurements performed in a reverse-to-forward voltage direction will yield higher open-circuit voltage (Voc), up to 10 mV, and smaller short-circuit current density (Jsc), by up to 2 mA/cm2, relative to scanning voltage in a forward-to-reverse direction. The variation at the maximum power point, Pmax, is however small. The resulting variation in FF can be as large as 3%. When Cu is not added, hysteresis in both Voc and Jsc is negligible however Pmax hysteresis is considerably greater. This behavior corroborates observed changes in depletion width, Wd, derived from capacitance (C) vs. voltage (V) scans. Measured values of Wd are always smaller in reverse-to-forward voltage scans, and conversely, larger in the forward-to-reverse voltage direction. Transient ion drift (TID) measurements performed on Cu-containing cells do not show ionic behavior suggesting that capacitance transients are more likely due to electronic capture-emission processes. J-V curve simulation using Pspice shows that increased transient capacitance during light-soak stress at 100 ºC correlates with increased space-charge recombination. Voltage-dependent collection however was not observed to increase with stress in these cells
Correlations of Capacitance-Voltage Hysteresis With Thin-Film CdTe Solar Cell Performance During Accelerated Lifetime Testing
In this paper we present the correlation of CdTe solar cell performance with capacitance-voltage hysteresis, defined presently as the difference in capacitance measured at zero-volt bias when collecting such data with different pre-measurement bias conditions. These correlations were obtained on CdTe cells stressed under conditions of 1-sun illumination, open-circuit bias, and an acceleration temperature of approximately 100 ºC
Use of 2nd and 3rd Level Correlation Analysis for Studying Degradation in Polycrystalline Thin-Film Solar Cells
The correlation of stress-induced changes in the performance of laboratory-made CdTe solar cells with various 2nd and 3rd level metrics is discussed. The overall behavior of aggregated data showing how cell efficiency changes as a function of open-circuit voltage (Voc), shortcircuit current density (Jsc), and fill factor (FF) is explained using a two-diode, PSpice model in which degradation is simulated by systematically changing model parameters. FF shows the highest correlation with performance during stress, and is subsequently shown to be most affected by shunt resistance, recombination and in some cases voltage-dependent collection. Large decreases in Jsc as well as increasing rates of Voc degradation are related to voltage-dependent collection effects and catastrophic shunting respectively. Large decreases in Voc in the absence of catastrophic shunting are attributed to increased recombination. The relevance of capacitance derived data correlated with both Voc and FF is discussed
Exposure to Parathion Effect on General Population and Asthmatics
There has been much lay and medical concern regarding toxic effects of insecticides on the general population. In addition to direct toxic effects, it is suspected that insecticidal application has deleterious physical effects on persons with respiratory diseases. To evaluate some of these problems, the authors have attempted to quantitate actual absorption, symptoms, and laboratory evidence of intoxication in persons with varying degrees of exposure to parathion. By means of controlled observations, the respiratory effect of application of this compound on persons with bronchial asthma was also measured. The results suggest that the effect of this chemical on the general population is negligible
Education Trajectories : From Early Childhood to Early Adulthood in Peru
Over the past few decades, every President in Peru has proclaimed education as a priority; yet, in spite of recent progress across several indicators, educational outcomes are still on average low, and gaps between students large and closely linked with their individual and family background. This paper looks at the education trajectories of children in different stages of life, using data from Young Lives, an international study that follows two groups of children: an Older Cohort (born in 1994) and a Younger Cohort (born in 2001). According to the Peruvian Constitution and General Education Law, education is considered a human right, and all students should have access to a quality service. However, results from our study and others suggest that while there have been important advances over the past two decades, there is still a long way to go for this to become a reality for everyone. Peruvian early childhood education consists of two types of preschool: Jardines, which are located in urban areas, and PRONOEI, which are usually in rural or impoverished areas. While attendance in preschool education has increased recently, our results show that by the age of 5 there are already differences in abilities that are related to family background. Furthermore, even after adjusting for these, children from Jardines have higher results in primary school than children from PRONOEI. Peruvian children are expected to attend primary school during middle childhood (ages 6 to 12), and most do. When we compare overage instances between the Older and Younger Cohort, it has been reduced, which is positive as more children are in their normative grade. Achievement in national and international assessments, as well as our own data, also show increases on average scores along with large gaps by wealth, area of residence, maternal education, and ethnicity. Regarding the latter, while Peruvian law states that children have the right to learn in their mother language, our results show that almost 39 per cent of indigenous children learn in Spanish only. In general, we find that educational opportunities are not fairly distributed. For example, urban schools (public and private) congregate richer, Spanish-speaking students and have better resources and more pedagogically able teachers; these students in turn have higher test results. During adolescence, children are expected to attend secondary schools. Overage at age 15 is higher than in primary, and continues to be related to the family background of students. During this period, we also find large gaps in achievement by student background. In regards to early adulthood, by about age 17 children should have finished secondary school: we found that nearly 68 per cent of our cohort had finished school at age 19 (42 per cent finished on age and 26 per cent overage); 20 per cent of adolescents had dropped out of school. Beyond secondary, young adults from Spanish-speaking homes, wealthier, and with more educated mothers (who had completed secondary education or above), are more likely to attend universities. Additionally, more than 38 per cent of the sample only worked and did not study at age 19; and in the case of women, 25 per cent already had children. Progress in enrolment and average achievement is clear in the educational trajectories of the two cohorts of children from early childhood to adulthood. This reflects the importance the population and successive governments have attributed to education. However, large disparities remain, related to students´ and family’s characteristics. In basic education, inequality is not related so much to access to school as it is to the educational opportunities children have at school, and their results in standardised tests. Children who come from relatively poor families, are indigenous, have a mother with less than complete secondary education, or who live in a rural family tend to have fewer opportunities and lower outcomes than their peers; the situation is worse for those who combine several of these family characteristics. Fortunately, disparities in opportunities and achievement by sex are relatively small. In tertiary education, there are still large gaps in access between groups, with privileged students having more access to university studies. Our conclusion is that the educational system may be reinforcing inequalities since it does not provide equal opportunities for all children; ideally, it should prioritise the opportunities of children and young adults who we know are more likely to have poor educational outcomes (i.e. vulnerable children). This should start at a young age, as we have found that gaps in achievement are evident by the age of 5. There are reasons to be optimistic, however, as public funding in education is increasing rapidly. In this scenario, we suggest that inequality in educational opportunities and outcomes becomes a priority
NUTRITIONAL STATUS OF 3-9 YEAR OLD CHILDREN IN THE ISLAND OF BORNHOLM::BASELINE ANTHROPOMETRIC DATA FROM PROJECT SOL- BORNHOLM
Breeding latitude predicts timing but not rate of spring migration in a widespread migratory bird in South America
Identifying the processes that determine avian migratory strategies in different environmental contexts is imperative to understanding the constraints to survival and reproduction faced by migratory birds across the planet. We compared the spring migration strategies of Fork‐tailed Flycatchers (Tyrannus s. savana) that breed at south‐temperate latitudes (i.e., austral migrants) vs. tropical latitudes (i.e., intratropical migrants) in South America. We hypothesized that austral migrant flycatchers are more time‐selected than intratropical migrants during spring migration. As such, we predicted that austral migrants, which migrate further than intratropical migrants, will migrate at a faster rate and that the rate of migration for austral migrants will be positively correlated with the onset of spring migration. We attached light‐level geolocators to Fork‐tailed Flycatchers at two tropical breeding sites in Brazil and at two south‐temperate breeding sites in Argentina and tracked their movements until the following breeding season. Of 286 geolocators that were deployed, 37 were recovered ~1 year later, of which 28 provided useable data. Rate of spring migration did not differ significantly between the two groups, and only at one site was there a significantly positive relationship between date of initiation of spring migration and arrival date. This represents the first comparison of individual migratory strategies among conspecific passerines breeding at tropical vs. temperate latitudes and suggests that austral migrant Fork‐tailed Flycatchers in South America are not more time‐selected on spring migration than intratropical migrant conspecifics. Low sample sizes could have diminished our power to detect differences (e.g., between sexes), such that further research into the mechanisms underpinning migratory strategies in this poorly understood system is necessary.Fil: Jahn, Alex. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Cereghetti, Joaquín. Universidad Nacional de La Pampa; ArgentinaFil: Cueto, Víctor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Esquel. Centro de Investigación Esquel de Montaña y Estepa Patagónica; ArgentinaFil: Hallworth, Michael T.. Smithsonian Conservation Biology Institute; Estados UnidosFil: Levey, Douglas J.. National Science Foundation; Estados UnidosFil: Marini, Miguel Â.. Universidade do Brasília; BrasilFil: Masson, Diego. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; ArgentinaFil: Pizo, Marco A.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Sarasola, José Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; ArgentinaFil: Tuero, Diego Tomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin
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