Universidade de Pernambuco

About: Universidade de Pernambuco is a education organization based out in Recife, Brazil. It is known for research contribution in the topics: Population & Medicine. The organization has 6147 authors who have published 6948 publications receiving 73648 citations.

Targeting helicase-dependent amplification products with an electrochemical genosensor for reliable and sensitive screening of genetically modified organisms.

Abstract: Cultivation of genetically modified organisms (GMOs) and their use in food and feed is constantly expanding; thus, the question of informing consumers about their presence in food has proven of significant interest. The development of sensitive, rapid, robust, and reliable methods for the detection of GMOs is crucial for proper food labeling. In response, we have experimentally characterized the helicase-dependent isothermal amplification (HDA) and sequence-specific detection of a transgene from the Cauliflower Mosaic Virus 35S Promoter (CaMV35S), inserted into most transgenic plants. HDA is one of the simplest approaches for DNA amplification, emulating the bacterial replication machinery, and resembling PCR but under isothermal conditions. However, it usually suffers from a lack of selectivity, which is due to the accumulation of spurious amplification products. To improve the selectivity of HDA, which makes the detection of amplification products more reliable, we have developed an electrochemical plat...

Dental anxiety and dental pain in 5- to 12-year-old children in Recife, Brazil.

Abstract: Dental anxiety is a common problem, related to dental pain, which contributes to irregular dental attendance and avoidance of dental care, resulting in poorer oral health during childhood. To evaluate anxiety, pain and/or discomfort related to dental treatment in 5- to 12-year-old children examined during a public holiday. This cross-sectional survey study was carried out with parental permission in 970 children of both sexes. Socio-economic status, dental anxiety and dental pain experience data were obtained through a questionnaire answered by parents or guardians. Dental anxiety was measured using the dental anxiety questionnaire (DAQ). The statistical analyses were performed using Pearson’s Chi-square test. The intra-examiner agreement was high (κ = 0.80) and the inter-examiner was κ = 0.79. The prevalence of dental anxiety was 39.4 % and that of a history of dental pain was 44.9 %. Dental anxiety among children was associated with the child never having had a dental appointment. The anxiety correlated positively with a history of dental pain (p < 0.001), the mother’s low level of schooling (p = 0.037), parents’ dental anxiety (p < 0.001), and negatively with visits to the dentist (p < 0.001). A high percentage of children presented with dental anxiety and a history of dental pain.

Entropy-Based Statistical Analysis of PolSAR Data

Abstract: Images obtained from coherent illumination processes are contaminated with speckle noise, with polarimetric synthetic aperture radar (PolSAR) imagery as a prominent example. With adequacy widely attested in the literature, the scaled complex Wishart distribution is an acceptable model for PolSAR data. In this perspective, we derive analytical expressions for the Shannon, Renyi, and restricted Tsallis entropy measurements under this model. Relationships between the derived measures and the parameters of the scaled Wishart law (i.e., the equivalent number of looks and the covariance matrix) are discussed. In addition, we obtain the asymptotic variances of the Shannon and Renyi entropy measurements when replacing distribution parameters by maximum-likelihood estimators. As a consequence, confidence intervals based on the Shannon and Renyi entropy measurements are also derived and proposed as new ways of capturing contrast. New hypothesis tests are additionally proposed using these results, and their performance is assessed using simulated and real data. In general terms, the test based on the Shannon entropy outperforms those based on Renyi entropy.

Diversidade de Scarabaeinae (Coleoptera, Scarabaeidae) coletados com armadilha de interceptação de vôo no Refúgio Ecológico Charles Darwin, Igarassu-PE, Brasil

Abstract: O objetivo deste trabalho foi estudar riqueza, abundância, diversidade e equitabilidade das especies de Scarabaeinae em dois ambientes no Refugio Ecologico Charles Darwin (RECD), Pernambuco. As coletas foram realizadas com armadilha de interceptacao de voo entre os meses de Abril e Junho de 2007, totalizando seis coletas. Foram capturados 4576 escarabeineos, pertencentes a 35 especies, 15 generos e seis tribos. Sete novos registros de especies foram feitos para Pernambuco, passando de 26 para 33 especies. As tribos registradas foram Canthonini, Ateuchini, Coprini, Phanaeini, Eurystenini e Onthophagini. Os generos melhor representados foram: Dichotomius com 84,6% dos besouros coletados, seguido por Canthidium com 7,62% e Canthon com 2,48%. A especie Dichotomius aff.sericeus foi a mais abundante com 3889 individuos. Em todo o estudo foram verificadas 17 especies para a area aberta, sendo 11 restritas a esse ambiente, enquanto para mata foram registradas 24, sendo 18 especies restritas. Grande parte dos individuos capturados na mata foi da especie D. aff.sericeus, enquanto no ambiente aberto nenhum individuo desta especie foi coletado. Os estimadores indicaram uma estimativa maxima de riqueza de 21 especies para o ambiente aberto e 32 especies para o ambiente de mata. A curva de acumulacao de especies baseada em valores de riqueza observada media para os dois ambientes do RECD, nao apresentou tendencia a assintota.