922 resultados para Invasive Weed


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Arborization can benefit coffee plantations by reducing the wind speed and temperature variation in the crop. It is also possible that the incident radiation can affect the weed populations and reduce the need for their control. This study aimed at assessing the weeds population and distribution, in arabica coffee intercropped with three macadamia cultivars, six years after planting, in Dois Córregos, São Paulo State, Brazil. Treatments consisted of a 3x3+1 factorial scheme, i.e., coffee intercropped with three macadamia cultivars (HAES 816, IAC 4-20 and IAC 9-20) and three sampling positions of weeds in the intercropping (in the macadamia tree canopy projection, among the macadamia tree canopies projections and in the single rows), plus an additional treatment (sole coffee). The weeds incidence and control, as well as their phytosociological characterization, were evaluated. For coffee intercropped with macadamia, the weeds occurrence and number of species were smaller than for sole coffee. For the projection in the canopy and among canopies of macadamia trees, there was an average decrease of 82% in the occurrence of weeds, in comparison with the sole coffee. The IAC 9-20 cultivar was more efficient in reducing the occurrence of weeds, when intercropped with coffee, for presenting a taller canopy, with a larger diameter.

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

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The invasive thistle Carduus nutans has been reported to be allelopathic, yet no allelochemicals have been identified from the species. In a search for allelochemicals from C. nutans and the closely related invasive species C. acanthoides, bioassay-guided fractionation of roots and leaves of each species were conducted. Only dichloromethane extracts of the roots of both species contained a phytotoxin (aplotaxene, (Z,Z,Z)-heptadeca-1,8,11,14-tetraene) with sufficient total activity to potentially act as an allelochemical. Aplotaxene made up 0.44 % of the weight of greenhouse-grown C. acanthoides roots (ca. 20 mM in the plant) and was not found in leaves of either species. It inhibited growth of lettuce 50%(I-50) in soil at a concentration of ca. 0.5 mg g(-1) of dry soil (ca. 6.5 mM in soil moisture). These values gave a total activity in soil value (molar concentration in the plant divided by the molarity required for 50 % growth inhibition in soil = 3.08) similar to those of some established allelochemicals. The aplotaxene I-50 for duckweed (Lemna paucicostata) in nutrient solution was less than 0.333 mM, and the compound caused cellular leakage of cucumber cotyledon discs in darkness and light at similar concentrations. Soil in which C. acanthoides had grown contained aplotaxene at a lower concentration than necessary for biological activity in our short-term soil bioassays, but these levels might have activity over longer periods of time and might be an underestimate of concentrations in undisturbed and/or rhizosphere soil.

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

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Selective neck dissection (SND) in clinical N-0 (cN(0)) cases of oral squamous cell carcinoma (SCC) has been performed by surgeons using a retroauricular or modified facelift approach with robotic or endoscopic assistance. However, these procedures provide cosmetic satisfaction at the cost of possible maximal invasiveness. In this prospective study, we introduced and evaluated the feasibility as well as surgical invasiveness and cosmetic outcome of endoscopically-assisted SND via a small submandibular approach.Forty-four patients with cT(1-2)N(0) oral SCC (OSCC) were randomly divided into two groups of endoscopically-assisted SND and conventional SND. Perioperative and postoperative outcomes of patients were evaluated, including the length of the incision, operating time for neck dissection, estimated blood loss during the operation, amount and duration of drainage, total hospitalization period, total number of lymph nodes retrieved, satisfaction scores based on the cosmetic results, perioperative local complications, shoulder syndrome, and follow-up information.The mean operation time in the endoscopically-assisted group (126.04 +/- A 12.67 min) was longer than that in the conventional group (75.67 +/- A 16.67 min). However, the mean length of the incision was 4.33 +/- A 0.76 cm in the endoscopically-assisted SND group, and the amount and duration of drainage, total hospital stay, postoperative shoulder pain score, and cosmetic outcomes were superior in the endoscopically-assisted SND group. Additionally, the retrieved lymph nodes and complications were comparable.Endoscopically-assisted SND via a small submandibular approach had a longer operation time than the conventional approach. However, endoscopically-assisted SND was feasible and reliable while providing minimal invasiveness and satisfactory appearance.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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