911 resultados para BIOTIC HOMOGENIZATION


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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For the first time, regulatory protocols defined in the OECD guidelines were applied to determine the fate properties of a nanopesticide in two agricultural soils with contrasting characteristics. The nanoformulation studied had no effect on the degradation kinetics of atrazine indicating that (1) the release of atrazine from the polymer nanocarriers occurred rapidly relative to the degradation kinetics (half-lives 36-53 days) and/or that (2) atrazine associated with the nanocarriers was subject to biotic or abiotic degradation. Sorption coefficients, derived from a batch and a centrifugation technique at a realistic soil-to-solution ratio, were higher for the nanoformulated atrazine than for the pure active ingredient. Results indicate that the nanoformulation had an effect on the fate of atrazine. However, since the protocols applied were designed to assess solutes, conclusions about the transport of atrazine loaded onto the nanocarriers should be made extremely cautiously. The centrifugation method applied over time (here over 7 days) appears to be a useful tool to indirectly assess the durability of nanopesticides under realistic soil-to-solution ratios and estimate the period of time during which an influence on the fate of the active ingredient may be expected. More detailed investigations into the bioavailability and durability of nanopesticides are necessary and will require the development of novel methods suitable to address both the "nano" and "organic" characteristics of polymer-based nanopesticides.

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

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Within a community, species may germinate at different times so as to mitigate competition and to take advantage of different aspects of the seasonal environment (temporal niche differentiation). We illustrated a hypothesis of the combined effects of abiotic and biotic competitive factors on germination timing and the subsequent upscale effects on community assembly. We estimated the germination timing (GT) for 476 angiosperm species of the eastern Tibetan Plateau grasslands under two light treatments in the field: high (i.e. natural) light and low light. We also measured the shift in germination timing (SGT) across treatments for all species. Furthermore, we used phylogenetic comparative methods to test if GT and SGT were associated with seed mass, an important factor in competitive interactions. We found a significant positive correlation between GT and seed mass in both light treatments. Additionally, small seeds (early germinating seeds) tended to germinate later and large seeds (late germinating seeds) tended to germinate earlier under low light vs high light conditions. Low light availability can reduce temporal niche differentiation by increasing the overlap in germination time between small and large seeds. In turn, reduced temporal niche differentiation may increase competition in the process of community assembly.

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

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The family Chironomidae is one of the most important groups within the macroinvertebrate communities, both in density and in richness, and because of its high adaptive value, has a wide distribution on the planet. These and other more specific features of each genus allow the use of this group of biomonitoring studies in the aquatic ecosystem, however, primarily, it is necessary to inventory the aquatic fauna. Thus, this study aimed to evaluate the taxonomic composition of Chironomidae associated with Eichhornia azurea in six lateral lagoons of Paranapanema River, where only five of them have very little information about the aquatic fauna associated with floating macrophytes. Furthermore, we analyzed the influence of environmental conditions on the richness and density of this community. Samples (biotic and abiotic) were held in March and August 2009 on the Ivo, Carmo, Sete Ilhas, Barbosa, Poço da Pedra and Coqueiral lagoons, which are upstream of the Jurumirim Reservoir. Samples with an area of 0.1976 m2 were collected at three banks of E. azurea of each lagoon. Then, they were washed in formaldehyde and water and fixed in 70% alcohol. The identification of morphospecies recorded 38 taxa (32 in March and 37 in August), where the Ivo lagoon is the richest (27 taxa). The density of each group varied according to each pond and is generally Asheum sp., Chironomus sp., Beardius sp., Parachironomus sp., Labrundinia sp., Tanytarsus sp., Ablabesmyia sp. and Polypedilum sp. the most representative. Limnophyes sp., Denopelopia sp., Paratanytarsus sp. and Parametriocnemus sp. were genders in lower density. The Dominance index ranged between 0.1490 (Barbosa Lagoon in March) and 0.4114 (Poço da Pedra Lagoon in March), and the Diversity Index ranged from 2.08 (Coqueiral Lagoon in March) and 3.58 (Barbosa Lagoon in August). The concentration of dissolved oxygen and pH were the environmental variables most correlated with the groups ...

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

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Planning is an essential instrument for the agricultural occupation of the lands, because it supports the activities of food production and raw materials. It must be driven by techniques that provide the sustainability of these activities, so that also ensures the environmental balance of agroecosystems. Lands misuse can be considered as one of the causes of frustration of agricultural activities. Thus, the occurrence of discrepancies between the effective use (real use) of the land and its agricultural aptitude can compete, in many cases, to the decrease of productivity, as well as for soil degradation. In this way, this research intends to study the relationship between the temporary cultivations, halfperennial cultures, perennial and its developmental environment, determining the edaphoclimatic characteristics of landscapes. From then on, a letter shall be subject to the use and occupation of the soil for agriculture in the municipality of Cristais Paulista-SP, aiming to describe the spatial organization of land use and vegetation cover, and emphasizing management and conservative practices. For that, climatic factors were characterized, fundamentally humidity, temperature and luminosity; edaphics, including parental material, chemical and physical properties, fertility, soil temperature and climatic zoning; biotic, referring to the suitability of different cultures or to be implanted; physical, such as geomorphology, slope, geology, hypsometry and hydrology; socioeconomic, in particular production and marketing seasons; and the way they all, together, affect the adaptation, distribution and production of crops. Using this information, the zoning of the area of study was done based on the 21 nominated groups obtained, in addition to recommendations and suggestions for handling each type of cultivation... (Complete abstract click electronic access below)

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The vocals are the most conspicuous means of communication between frogs and can express evolutionary relationships among species. Call descriptions of frogs, in general, not standard acoustic parameters which are greatly diversified and usually restricted to comparisons between closely related taxa. The Atlantic Forest is considered one of the biodiversity hotspots of the world, however, it appears that the number of species to be known is still very large. To anurans from this Brazilian Domain, vocalizations are complex and can vary intra and interpopulations. Thus, we presented a quantitative and qualitative analysis of the work descriptions of anuran advertisement call from the Atlantic Forest, available in the literature so far. The frog species from this Domain and their descriptions of the advertisement call have been raised in the literature, organized into families and threat category IUCN Red List Threatened Species. The analysis of the descriptions were made based on the presence of preset parameters. It was observed that the species which the advertisement call is described within the standard are expected within the Brazilian Atlantic Domain, but efforts to describe the advertisement call of frogs of the Atlantic are concentrated in non-threatened species. Among the descriptions works, there is a large discrepancy between the information presented, giving preference to the use of abiotic data in this kind of work, to the detriment of biotic data about choir where the songs were recorded. The results point to the need for advancements in the descriptions of the advertisement of endangered species or to those with deficient information on their conservation status in the Atlantic Forest, and also for greater communication between works that describe vocalizations of frogs. It will be important to know about the state of the art of descriptions works of frogs in other Brazilian Domains, and relate this information with knowledge...

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The objective of the present work was to evaluate Pinus’ glued laminated timber (glulam) beams and steel reinforced glulam beams, using PU mono-component adhesive in lamination step and epoxy adhesive to bond steel bars. The mechanical performance was verified through bending test, and the adopted method based on homogenized section, to considerate the differences between wood and steel mechanical properties. The homogenization section method proved itself effective in obtaining the stiffness of the parts in MLCA. The stiffness of reinforced beams increased 91% in comparison with glulam beams, differing only 5.5 % from value of stiffness calculated