667 research outputs found

    Calibration of a wide angle stereoscopic system

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    This paper was published in OPTICS LETTERS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OL.36.003064. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.Inaccuracies in the calibration of a stereoscopic system appear with errors in point correspondences between both images and inexact points localization in each image. Errors increase if the stereoscopic system is composed of wide angle lens cameras. We propose a technique where detected points in both images are corrected before estimating the fundamental matrix and the lens distortion models. Since points are corrected first, errors in point correspondences and point localization are avoided. To correct point location in both images, geometrical and epipolar constraints are imposed in a nonlinear minimization problem. Geometrical constraints define the point localization in relation to its neighbors in the same image, and eipolar constraints represent the location of one point referred to its corresponding point in the other image. © 2011 Optical Society of America.Ricolfe Viala, C.; Sánchez Salmerón, AJ.; Martínez Berti, E. (2011). Calibration of a wide angle stereoscopic system. Optics Letters. 36(16):3064-3067. doi:10.1364/OL.36.003064S306430673616Zhang, Z., Ma, H., Guo, T., Zhang, S., & Chen, J. (2011). Simple, flexible calibration of phase calculation-based three-dimensional imaging system. Optics Letters, 36(7), 1257. doi:10.1364/ol.36.001257Longuet-Higgins, H. C. (1981). A computer algorithm for reconstructing a scene from two projections. Nature, 293(5828), 133-135. doi:10.1038/293133a0Ricolfe-Viala, C., & Sanchez-Salmeron, A.-J. (2010). Lens distortion models evaluation. Applied Optics, 49(30), 5914. doi:10.1364/ao.49.005914Armangué, X., & Salvi, J. (2003). Overall view regarding fundamental matrix estimation. Image and Vision Computing, 21(2), 205-220. doi:10.1016/s0262-8856(02)00154-3Devernay, F., & Faugeras, O. (2001). Straight lines have to be straight. Machine Vision and Applications, 13(1), 14-24. doi:10.1007/pl0001326

    Qualitative and quantitative response of soil organic carbon to 40 years of crop residue incorporation under contrasting nitrogen fertilisation regimes

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    Crop residue incorporation (RI) is recommended to increase soil organic carbon (SOC) stocks. However, the positive effect on SOC is often reported to be relatively low and alternative use of crop residues, e.g. as a bioenergy source, may be more climate smart. In this context, it is important to understand: (i) the response of SOC stocks to long-term crop residue incorporation; and (ii) the qualitative SOC change, in order to judge the sustainability of this measure. We investigated the effect of 40 years of RI combined with five different nitrogen (N) fertilisation levels on SOC stocks and five SOC fractions differing in turnover times on a clay loam soil in Padua, Italy. The average increase in SOC stock in the 0–30cm soil layer was 3.1Mgha–1 or 6.8%, with no difference between N fertilisation rates. Retention coefficients of residues did not exceed 4% and decreased significantly with increasing N rate (R2=0.49). The effect of RI was higher after 20 years (4.6Mgha–1) than after 40 years, indicating that a new equilibrium has been reached and no further gains in SOC can be expected. Most (92%) of the total SOC was stored in the silt and clay fraction and 93% of the accumulated carbon was also found in this fraction, showing the importance of fine mineral particles for SOC storage, stabilisation and sequestration in arable soils. No change was detected in more labile fractions, indicating complete turnover of the annual residue-derived C in these fractions under a warm humid climate and in a highly base-saturated soil. The applied fractionation was thus useful to elucidate drivers and mechanisms of SOC formation and stabilisation. We conclude that residue incorporation is not a significant management practice affecting soil C storage in warm temperate climatic regions

    Oviposição e predação de Pentilia egena mulsant (Coleoptera: Coccinellidae) em resposta à temperatura

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    The species Pentilia egena Mulsant is an important predator of armored scales that occur in citrus orchards in Brazil. To intensify this biological control, knowing bioecological aspects in necessary for the improvement of massal insect rearing. This research investigated the influence of temperature (19ºC, 24ºC and 29ºC) on the number of eggs laid by P. egena and the number of Aspidiotus nerii Bouché scales preyed by this coccinellid. The highest number of eggs laid and of scales preyed, 5.1 ± 0.59 and 11.3 ± 0.19, respectively, occurred at 29ºC. However, egg viability (52.86%) was reduced at this temperature, and was lower than those at 19ºC and 24ºC (78.10% and 74.07%, respectively). Temperature did not affect the ladybeetle oviposition behavior as the eggs were laid under the scale of preyed A. nerii.A espécie Pentilia egena Mulsant é importante predadora de cochonilas de carapaças que ocorrem em pomares citrícolas no Brasil. Para intensificar ainda mais este controle biológico, há necessidade de conhecimento dos aspectos bioecológicos deste predador para o aperfeiçoamento de sua criação massal. Este trabalho teve como objetivo estudar a influência da temperatura (19ºC, 24ºC e 29ºC) na oviposição de P. egena e na intensidade de predação de cochonilhas Aspidiotus nerii Bouché. A 29ºC observaram-se maiores médias de cochonilhas predadas e de ovos colocados, respectivamente, 5,1 ± 0,59 e 11,3 ± 0,19, que nas duas outras temperaturas. Entretanto, a viabilidade dos ovos foi inferior (52,86%), quando comparada àquela obtidas a 19ºC e 24ºC (78,10% e 74,07%, respectivamente). A temperatura não afetou o comportamento de oviposição deste coccinelídeo, sendo os ovos, preferencialmente, colocados sob a carapaça das cochonilhas já predadas

    Calcium Intake By Adolescents: A Population-based Health Survey

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    Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)To analyze calcium intake in adolescents according to sociodemographic variables, health-related behaviors, morbidities, and body mass index. Methods: This was a cross-sectional population-based study, with a two-stage cluster sampling that used data from a survey conducted in Campinas, Sao Paulo, Brazil, between 2008 and 2009. Food intake was assessed using a 24-hour dietary recall. The study included 913 adolescents aged 10-19 years. Results: Average nutrient intake was significantly lower in the segment with lower education of the head of the family and lower per capita family income, in individuals from other cities or states, those who consumed fruit less than four times a week, those who did not drink milk daily, those who were smokers, and those who reported the occurrence of headaches and dizziness. Higher mean calcium intake was found in individuals that slept less than seven hours a day. The prevalence of calcium intake below the recommendation was 88.6% (95% CI: 85.4-91.2). Conclusion: The results alert to an insufficient calcium intake and suggest that certain subgroups of adolescents need specific strategies to increase the intake of this nutrient. (C) 2015 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.923251259Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) [409747/2006-8]Municipal Health Secretariat of CampinasHealth Surveillance Secretariat of the Ministry of Health [ISACAMP 2008]CAPESConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

    Are Normal-weight Adolescents Satisfied With Their Weight?

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    The high prevalence of obesity has led to public policies for combating it. People with normal weight may gain greater awareness of this issue and change their perceptions of their weight. The aim of this study was to evaluate the prevalence of body weight dissatisfaction among normal-weight adolescents, according to demographic and socioeconomic variables, health-related behavior and morbidities. DESIGN AND SETTING: Population-based cross-sectional study that used data from a health survey conducted in the city of Campinas, Sao Paulo, in 2008-2009. METHODS: The prevalence and prevalence ratios of weight dissatisfaction were estimated according to independent variables, by means of simple and multiple Poisson regression. RESULTS: 573 normal-weight adolescents aged 10 to 19 years (mean age 14.7 years) were analyzed. The prevalence of weight dissatisfaction was 43.7% (95% confidence interval, CI: 37.8-49.8). Higher prevalences of weight dissatisfaction were observed among females, individuals aged 15 to 19 years, those whose households had eight or more domestic appliances, former smokers, individuals who reported alcohol intake and those who had one or more chronic diseases. Lower prevalence of dissatisfaction was observed among adolescents living in substandard housing. Among the normal-weight adolescents, 26.1% wished to lose weight and 17.6% wished to gain weight. CONCLUSION: The results from this study indicate that even when weight is seen to be within the normal range, a high proportion of adolescents express dissatisfaction with their weight, especially females, older adolescents and those of higher socioeconomic level.1343219227Conference on Defense of the Master's Thesis of Mariana Contiero San MartiniAUG 12, 2015State Univ Campinas, Limeira, BRAZI

    Stakeholder perspectives to prevent soil organic matter decline in Northeastern Italy

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    A transition from conventional to more sustainable soil management measures (SMMs) is required to reverse the current soil organic matter (SOM) losses in the agroecosystems. Despite the innovations and technologies that are available to prevent SOM decline, top–down knowledge transfer schemes that incentivize a certain measure are often ineffective. Here, we discuss relevant outcomes from a participatory approach where researchers, farmers, practitioners and government officials have discussed opportunities and barriers around SMM application to prevent SOM decline. Within a series of workshops, stakeholders identified, scored, and selected SMMs to fieldtests and evaluated the benefits and drawbacks from their application. Results showed that the stakeholders recognized the need for innovations, although they valued the most promising SMM as already available continuous soil cover and conservation agriculture. In contrast, more innovative SMMs, such as biochar use and the variable rate application of organic amendments through precision farming, were the least valued, suggesting that people’s resistance to new technologies is often governed by the socio-cultural perception of them that goes beyond the economic and technological aspects. The valuation of benefits and drawbacks by stakeholders on trialed measures emphasized that stakeholders’ perspective about soil management is a combination of economic, environmental, and socio-cultural aspects, thus corroborating the need for transdisciplinary bottom–up approaches to prevent SOM depletion and increase soil rehabilitation and SOM content

    SHARENTING: VIOLAÇÃO DO DIREITO DE IMAGEM DAS CRIANÇAS E ADOLESCENTES PELOS PRÓPRIOS GENITORES NA ERA DIGITAL

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    O tema da pesquisa é o fenômeno conhecido como sharenting, caracterizado pela violação ao direito de imagem das crianças e dos adolescentes pelos próprios genitores, com a utilização das mídias sociais. O objetivo do estudo é refletir sobre o grau de incidência desse fenômeno, em especial porque o tempo atual é o da Era Digital. Para tanto, emprega-se neste estudo o método hipotético-dedutivo, com a utilização de livros e artigos científicos publicados em revistas especializadas e em sites. Conclui-se que o uso desregrado do sharenting fere o direito à imagem de crianças e adolescentes, considerado direito da personalidade

    Adolescentes eutróficos estão satisfeitos com o seu peso?

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    : CONTEXT AND OBJECTIVE: The high prevalence of obesity has led to public policies for combating it. People with normal weight may gain greater awareness of this issue and change their perceptions of their weight. The aim of this study was to evaluate the prevalence of body weight dissatisfaction among normal-weight adolescents, according to demographic and socioeconomic variables, health-related behavior and morbidities. DESIGN AND SETTING: Population-based cross-sectional study that used data from a health survey conducted in the city of Campinas, São Paulo, in 2008-2009. METHODS: The prevalence and prevalence ratios of weight dissatisfaction were estimated according to independent variables, by means of simple and multiple Poisson regression. RESULTS: 573 normal-weight adolescents aged 10 to 19 years (mean age 14.7 years) were analyzed. The prevalence of weight dissatisfaction was 43.7% (95% confidence interval, CI: 37.8-49.8). Higher prevalences of weight dissatisfaction were observed among females, individuals aged 15 to 19 years, those whose households had eight or more domestic appliances, former smokers, individuals who reported alcohol intake and those who had one or more chronic diseases. Lower prevalence of dissatisfaction was observed among adolescents living in substandard housing. Among the normal-weight adolescents, 26.1% wished to lose weight and 17.6% wished to gain weight. CONCLUSION: The results from this study indicate that even when weight is seen to be within the normal range, a high proportion of adolescents express dissatisfaction with their weight, especially females, older adolescents and those of higher socioeconomic level.: CONTEXTO E OBJETIVO: Com a alta prevalência da obesidade levando a políticas públicas para o seu enfrentamento, pessoas com o peso adequado podem se sensibilizar e alterar sua percepção sobre o seu peso. Objetivou-se avaliar a prevalência de insatisfação com o peso corporal em adolescentes eutróficos, segundo variáveis demográficas e socioeconômicas, comportamentos relacionados à saúde e morbidades. TIPO DE ESTUDO E LOCAL: Estudo transversal de base populacional que utilizou dados do Inquérito de Saúde realizado em Campinas (SP), em 2008/2009. MÉTODOS: Foram estimadas as prevalências e as razões de prevalência de insatisfação com o peso segundo as variáveis independentes, por meio de regressão simples e múltipla de Poisson. RESULTADOS: Analisaram-se 573 adolescentes eutróficos de 10 a 19 anos, com idade média de 14,7 anos. A insatisfação com o peso atingiu prevalência de 43,7% (intervalo de confiança de 95%, IC: 37,8-49,8). Maiores prevalências de insatisfação com o peso foram verificadas no sexo feminino, nos adolescentes de 15 a 19 anos, que possuíam oito ou mais equipamentos na residência, nos ex-fumantes, nos que relataram ingerir bebida alcoólica e nos que apresentavam uma ou mais doenças crônicas. Menor prevalência de insatisfação foi observada nos adolescentes que residiam em moradias com condições inadequadas. Dos adolescentes eutróficos, 26,1% queriam perder peso e 17,6% desejavam ganhar. CONCLUSÕES: Os resultados apontam que, mesmo apresentando o peso dentro da faixa de normalidade, elevada proporção de adolescentes manifesta-se insatisfeita com o seu peso, em especial os indivíduos de sexo feminino, os mais velhos e os de melhor nível socioeconômico.134321922
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