172 research outputs found
Marginal bone loss in the second molar related to impacted mandibular third molars : comparison between panoramic images and cone beam computed tomography
Deciding whether or not to extract third molars remains a controversial situation in dental practice. Image exams support this decision by enabling a close view of the third molar, its adjacent bone and its relationship with the second molar. This study aimed to assess and compare second molar bone loss adjacent to impacted mandibular third molar in panoramic radiographs (PAN) and cone beam computed tomography (CBCT) scans. A sample of 70 patients was selected (n=124 teeth). Each patient had a set of a panoramic radiograph and CBCT scans consecutively taken for dental treatment purposes. In PAN and CBCT, mandibular third molars were classified based on their position and bone loss of the adjacent second molar. Agreement between PAN and CBCT scans was assessed and quantified. Outcomes of bone loss assessment were different between PAN and CBCT scans (p<0.05). Bone loss was found in 62.9% of the PAN, while in CBCT scans it was found in 80%. In particular, nearly 29% (n=27) of the teeth that were classified without bone loss in PAN were classified with bone loss in CBCT scans. Mesioangular and horizontal third molars had a statistically significant association with bone loss of the adjacent second molars (p<0.05). In general, PAN underestimated the severity of bone loss compared to CBCT scans (p<0.05). Diagnosing second molar bone loss due to impaction of adjacent third molar in PAN may be challenging because of false negatives. Impacted third molars justify preoperative CBCT scans if second molar bone loss needs to be precisely assessed for a more detailed and reliable treatment plan
Application of sources and levels of calcium on production and quality of muskmelon fruits
Foi avaliado o efeito de diferentes fontes e doses de cálcio sobre
a produção e qualidade de frutos de melão híbrido ‘Gold Mine’
(Cucumis melo var. inodurus). O delineamento experimental foi de
blocos casualizados, com quatro repetições em esquema fatorial 5 x
2, compreendendo cinco doses de cálcio (0; 2,5; 5,0; 7,5 e 10,0 kg/
ha de Ca) e duas fontes de cálcio [CaCl2
P.A. (26% Ca) e CaB2
quelatizado (8% Ca)]. As pulverizações foram iniciadas na antese e
dirigidas para os frutos e nas folhas próximas aos frutos. O cálcio
quelatizado (CaB2
) foi mais efetivo no pegamento de fruto, resultando
em um número maior de frutos por planta, maior produção
comercial, firmeza e espessura de polpa de frutos, quando comparado
com o CaCl2
. Embora os teores de cálcio na matéria seca da casca
e da polpa e açúcares totais dos frutos foram superiores na dosagem
de 10,0 kg/ha, esta proporcionou sintomas visuais de fitotoxidez
de cálcio na folha. Não houve influência de fontes e de doses de
cálcio nos caracteres de pH e sólidos solúveis totais (SST)._________________________________________________________________________________________ ABSTRACT: d quality of muskmelon (Cucumis melo var. inodorus) fruits, hybrid
‘Gold Mine’, stored at room temperature were evaluated. A
randomized complete block design was used in a 5x2 factorial
scheme, with four replications, consisting of five levels of calcium
(0; 2.5; 5.0; 7.5 and 10.0 kg/ha of Ca) and two sources [CaCI2
P.A.
(26% Ca) and CaB2
(8% Ca)]. Sprays started at anthesis and were
directed to the fruits and to the leaves close to the fruits. The chelated
calcium (CaB2
) was more efficient on fruit set, which resulted in a
greater number of fruits per plant, and provided greater marketable
fruit production, firmness and fruit pulp thickness, when compared
to CaCl2
. At 10 kg/ha of calcium there was higher calcium level in
the flesh and skin of fruits and higher total sugar content, but calcium
toxicity symptoms were observed. Calcium sources and levels did
not affect fruit pH and total soluble solids (TSS)
Effect of Insecticide Resistance on Development, Longevity and Reproduction of Field or Laboratory Selected Aedes aegypti Populations
Aedes aegypti dispersion is the major reason for the increase in dengue transmission in South America. In Brazil, control of this mosquito strongly relies on the use of pyrethroids and organophosphates against adults and larvae, respectively. In consequence, many Ae. aegypti field populations are resistant to these compounds. Resistance has a significant adaptive value in the presence of insecticide treatment. However some selected mechanisms can influence important biological processes, leading to a high fitness cost in the absence of insecticide pressure. We investigated the dynamics of insecticide resistance and its potential fitness cost in five field populations and in a lineage selected for deltamethrin resistance in the laboratory, for nine generations. For all populations the life-trait parameters investigated were larval development, sex ratio, adult longevity, relative amount of ingested blood, rate of ovipositing females, size of egglaying and eggs viability. In the five natural populations, the effects on the life-trait parameters were discrete but directly proportional to resistance level. In addition, several viability parameters were strongly affected in the laboratory selected population compared to its unselected control. Our results suggest that mechanisms selected for organophosphate and pyrethroid resistance caused the accumulation of alleles with negative effects on different life-traits and corroborate the hypothesis that insecticide resistance is associated with a high fitness cost
EFFECT OF TIMBER HARVESTING ON DENSITY AND BASAL AREA OF LECYTHIDACEAE SPECIES IN THE EASTERN AMAZON
Dynamics of Lecythidaceae species were evaluated 13 years after logging in a dense tropical rain forest located in the municipality of Moju, Pará (02º 08’ 14’’ and 02º 12’ 26” S; 48º 47’ 34”S and 48º 48’ 14” W - SAD 69). Two hundred ha out of a 1,050 ha forest area were selectively logged for timber (23 m3 ha-1 harvested from 25 species) in 1997. Twenty-two permanent sample plots of 0.5 ha (11 ha sample area) were established and all trees with DBH ≥ 10 cm were measured and identified in 1995, 1998 and 2010. Density (trees ha-1) and basal area (m2 ha-1) of the species were evaluated in the three occasions. The opening of canopy caused by logging reduced the density and basal area of five species, but produced a positive response in nine species, boosting their natural regeneration and allowing the ingrowth of one species that was not present in the studied area in the beginning.Keywords: Forest dynamics; Tauari; forest management; Amazon Forest. ResumoEfeito da exploração de madeiras na densidade e área basal de espécies de Lecythidaceae no leste da Amazônia. Analisou-se a dinâmica de espécies de Lecythidaceae 13 anos após a exploração madeireira, em uma Floresta Ombrófila Densa no município de Moju, Pará (02º 08’ 14’’ e 02º 12’ 26” S; 48º 47’ 34”S e 48º 48’ 14” W - SAD 69). De uma área de floresta de 1.050 ha, foram selecionados 200 ha para exploração seletiva, em 1997, de 25 espécies comerciais madeireiras (intensidade de 23 m3 ha-1). Foram alocadas 22 parcelas permanentes de 0,5 ha, totalizando 11 ha amostrais, onde foram medidas todas as árvores com DAP≥ 10 cm, nos anos de 1995, 1998 e 2010. Analisou-se a densidade (árvores ha-1) e área basal (m2 ha-1) das espécies, nas três ocasiões. A abertura do dossel causada pela exploração reduziu a densidade e a área basal de cinco espécies, porém produziu impacto positivo em nove espécies, estimulando a sua regeneração natural e, inclusive, proporcionando o ingresso de uma espécie que não estava presente na área monitoradaPalavras-chave: Dinâmica da floresta; Tauarí; manejo florestal; Floresta Amazônica.Dynamics of Lecythidaceae species were evaluated 13 years after logging in a dense tropical rain forest located in the municipality of Moju, Pará (02º 08’ 14’’ and 02º 12’ 26” S; 48º 47’ 34”S and 48º 48’ 14” W - SAD 69). Two hundred ha out of a 1,050 ha forest area were selectively logged for timber (23 m3 ha-1 harvested from 25 species) in 1997. Twenty-two permanent sample plots of 0.5 ha (11 ha sample area) were established and all trees with DBH ≥ 10 cm were measured and identified in 1995, 1998 and 2010. Density (trees ha-1) and basal area (m2 ha-1) of the species were evaluated in the three occasions. The opening of canopy caused by logging reduced the density and basal area of five species, but produced a positive response in nine species, boosting their natural regeneration and allowing the ingrowth of one species that was not present in the studied area in the beginning.Keywords: Forest dynamics; Tauari; forest management; Amazon Forest
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