988 resultados para Amazon cone


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Small-scale farmers in the Brazilian Amazon collectively hold tenure over more than 12 million ha of permanent forest reserves, as required by the Forest Code. The trade-off between forest conservation and other land uses entails opportunity costs for them and for the country, which have not been sufficiently studied. We assessed the potential income generated by multiple use forest management for farmers and compared it to the income potentially derived from six other agricultural land uses. Income from the forest was from (i) logging, carried out by a logging company in partnership with farmers' associations; and (ii) harvesting the seeds of Carapa guianensis (local name andiroba) for the production of oil. We then compared the income generated by multiple-use forest management with the income from different types of agrarian systems. According to our calculations in this study, the mean annual economic benefits from multiple forest use are the same as the least productive agrarian system, but only 25% of the annual income generated by the most productive system. Although the income generated by logging may be considered low when calculated on an annual basis and compared to incomes generated by agriculture, the one-time payment after logging is significant (US$5,800 to US$33,508) and could be used to implement more intensive and productive cropping systems such as planting black pepper. The income from forest management could also be used to establish permanent fields in deforested areas for highly productive annual crops using conservation agriculture techniques. These techniques are alternatives to the traditional land use based on periodic clearing of the forest. Nevertheless, the shift in current practices towards adoption of more sustainable conservation agriculture techniques will also require the technical and legal support of the State to help small farmers apply these alternatives, which aim to integrate forest management in sustainable agricultural production systems.

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With the emergence of new filling materials with different properties and behaviors, the approach of endodontic treatment must be readjusted so that the appropriate result can be achieved. New endodontic sealers include methacrylate resin-based, plant resin-based and the evolution of epoxy-based sealers. This study verified the behavior of new materials that presents controversial results in the literature, about coronal bacterial leakage. That for, 56 single-rooted human teeth were prepared in the direction crown-apex and filled with gutta-percha points with taper of 4% using the single cone technique. Roots were divided randomly into 4 groups according to the sealer (Apexit Plus, AH Plus, EndoREZ and Polifil). After filling, the roots were incorporated in a leakage model, which upper chamber contained a suspension of Streptococcus mutans, and lower chamber a broth, leaving 3 mm of root apical portion immersed. Leakage was assessed for turbidity in lower chamber every day for 60 days. Survival analysis was performed using the nonparametric Kaplan- Meier method (p<0,05). All experimental groups presented leakage during the study’s period, however the maximum time achieve was 22 days. The medium time of leakage was: Apexit Plus 6,3 days, AH Plus 6,3 days and Polifil 5,1 days, but in EndoREZ all specimens infiltrated in the first day, presenting shorter capacity of impermeabilization compared to the other groups. Concluding that none of the sealers tested was able to prevent coronal bacterial leakage

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We evaluated the frequency of different HLA-DRB1 alleles in Plasmodium vivax-infected individuals and in healthy blood donors from malaria endemic areas of Brazil. Low-resolution human leukocyte antigen-DRB1 genotyping was performed for 73 malaria patients and 29 healthy blood donors. The most frequent alleles in individuals from northern Brazil were human leukocyte antigen-DRB1*04, *08, *07 and *13. The frequency of human leukocyte antigen-DRB1*07 was higher in malaria-infected individuals than in the control group, which reinforces the theory that this allele plays an important role in susceptibility to malaria. This study offers new information about a potential susceptibility factor for P. vivax malaria in a Brazilian population that is naturally exposed to malaria.

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Despite the Amazon Forest being the largest tropical forest in the world, and cradle of rubber trees (Hevea brasiliensis), no studies have aimed to report the occurrence of mites associated with native trees from this ecosystem. Our survey investigates the phytoseiid mites associated with five species of native rubber trees from nine sites of the Amazon Forest, and also presents a major review of phytoseiid species from natural vegetation in Brazil. We found a total of 1305 mites, belonging to 30 species, of which seven were new to science, Amblydromalus akiri sp. nov., Amblyseius chicomendesi sp. nov., Amblyseius duckei sp. nov., Amblyseius manauara sp. nov., Iphiseiodes katukina sp. nov., Iphiseiodes raucuara sp. nov. and Typhlodromips igapo sp. nov.; beyond two new records for Brazil, Iphiseiodes kamahorae and Amblyseius martus. Our results emphasize the importance of Amazon native trees as an unexplored source of predator mites, which in turn may be further studied as biological control agents of pest mites on rubber trees. The impressive diversity, endemism and rate of new species found highlight the importance of studies on arthropod communities associated with the Amazon vegetation.

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To assess the influence of anatomic location on the relationship between computed tomography (CT) number and X-ray attenuation in limited and medium field-of-view (FOV) scans. Materials and Methods Tubes containing solutions with different concentrations of K2HPO4 were placed in the tooth sockets of a human head phantom. Cone-beam computed tomography (CBCT) scans were acquired, and CT numbers of the K2HPO4 solutions were measured. The relationship between CT number and K2HPO4 concentration was examined by linear regression analyses. Then, the variation in CT number according to anatomic location was examined. Results The relationship between K2HPO4 concentration and CT number was strongly linear. The slopes of the linear regressions for the limited FOVs were almost 2-fold lower than those for the medium FOVs. The absolute CT number differed between imaging protocols and anatomic locations. Conclusion There is a strong linear relationship between X-ray attenuation and CT number. The specific imaging protocol and anatomic location of the object strongly influence this relationship.

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The hypertrophy of the mandibular coronoid process is a rare condition, progressive and of unknown etiology, characterized by the over development of the coronoid process determining their size increased, resulting in progressive and painful limitation of mouth opening. The mandibular hypomobility is a present symptom in several diseases and associates it to a specific cause requires detailed clinical and imaginologic examination. The cone-beam computed tomography has the potential to provide complementary informations above than conventional radiography. It also has the advantage of eliminate overlaps, provide high resolution image, helping not only in diagnosis, but also in planning the surgical procedure. Here we report a case of male patient, who appeared at the clinic for an evaluation of a trismus. He had no pain, only discomfort for progressive limitation of mouth opening. On physical examination, only a limited mouth opening has been found. Although the movements of laterality and protrusión were posible, they were very limited. Cone-beam computed tomography examination was performed, that showed an image compatible with bilateral hypertrophy of the mandibular coronoid process.

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The aim of this study was to evaluate in vitro the apical leakage after the apical re-preparation and replacement of the principal gutta-percha point plus endodontic sealer (Sealer 26TM). Sixty extracted human canines were prepared by using a step back technique up to size 50 K type file apically. At each change of instrument the canals were irrigated with distilled water. After that step, the external surface roots were coated and subdivided into six groups with ten roots each: I – single gutta percha point technique; II – lateral condensation and III – hybrid technique. The IV, V and VI groups were similar to others groups but after to place the principal gutta percha point, it was removed, re-prepared up to size 60K file and in sequence replaced the principal gutta percha point and the root canal filling finished. The specimens were immersed in 2% Rhodamine BTM for 7 days at 37 oC. The apical leakage was measured by Image ToolsTM program. With Kruskal Wallis test statistical analysis showed that there was no significant difference between the techniques (p > 0.05).

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The ability to tridimensionally evaluate pathological and anatomical areas, in apical surgery planning, presents a number of advantages. Cone beam computed tomography (CBCT) was developed for dental applications. This paper aims to present a literature review on CBCT, highlighting its advantages over both conventional computed tomography (CT) and radiography. Moreover, its clinical applications in apical surgery are discussed. LITERATURE REVIEW AND CONCLUSION: Unlikely CT, CBCT captures a volume of data in a single 360º rotation, providing benefits such as higher accuracy, better resolution, reduced scanning time and reduced radiation dose. In the maxillofacial region, CBCT has been mainly used in the assessment of dento-alveolar pathology and oral traumatology. CBCT provides a better diagnosis and quantitative information on periodontal bone levels than conventional radiography. It has also been used for patients requiring surgical facial reconstruction, orthognathic surgery, dental implants, and more complex tooth extractions. Besides that, it seems to be a significant tool in modern endodontic practice, presenting useful applications in apical surgery.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)