Algebraic Characterization of the Lorentz and Diffeomorphism Anomalies

The Wess-Zumino consistency conditions for Lorentz and diffeomorphism anomalies are discussed by introducing an operator 'delta' which allows to decompose the exterior derivative as a BRS commutator.Comment: 23 pages, LateX, REF.SISSA 24/93/E

Ghost Equations and Diffeomorphism Invariant Theories

Four-dimensional Einstein gravity in the Palatini first order formalism is shown to possess a vector supersymmetry of the same type as found in the topological theories for Yang-Mills fields. A peculiar feature of the gravitational theory, characterized by diffeomorphism invariance, is a direct link of vector supersymmetry with the field equation of motion for the Faddeev-Popov ghost of diffeomorphisms.Comment: LaTex, 10 pages; sign corrected in eq. (3.9); added and completed reference

Algebraic structure of gravity in Ashtekar variables

The BRST transformations for gravity in Ashtekar variables are obtained by using the Maurer-Cartan horizontality conditions. The BRST cohomology in Ashtekar variables is calculated with the help of an operator $\delta$ introduced by S.P. Sorella, which allows to decompose the exterior derivative as a BRST commutator. This BRST cohomology leads to the differential invariants for four-dimensional manifolds.Comment: 19 pages, report REF. TUW 94-1

Markedly Divergent Tree Assemblage Responses to Tropical Forest Loss and Fragmentation across a Strong Seasonality Gradient

We examine the effects of forest fragmentation on the structure and composition of tree assemblages within three seasonal and aseasonal forest types of southern Brazil, including evergreen, Araucaria, and deciduous forests. We sampled three southernmost Atlantic Forest landscapes, including the largest continuous forest protected areas within each forest type. Tree assemblages in each forest type were sampled within 10 plots of 0.1 ha in both continuous forests and 10 adjacent forest fragments. All trees within each plot were assigned to trait categories describing their regeneration strategy, vertical stratification, seed-dispersal mode, seed size, and wood density. We detected differences among both forest types and landscape contexts in terms of overall tree species richness, and the density and species richness of different functional groups in terms of regeneration strategy, seed dispersal mode and woody density. Overall, evergreen forest fragments exhibited the largest deviations from continuous forest plots in assemblage structure. Evergreen, Araucaria and deciduous forests diverge in the functional composition of tree floras, particularly in relation to regeneration strategy and stress tolerance. By supporting a more diversified light-demanding and stress-tolerant flora with reduced richness and abundance of shade-tolerant, old-growth species, both deciduous and Araucaria forest tree assemblages are more intrinsically resilient to contemporary human-disturbances, including fragmentation-induced edge effects, in terms of species erosion and functional shifts. We suggest that these intrinsic differences in the direction and magnitude of responses to changes in landscape structure between forest types should guide a wide range of conservation strategies in restoring fragmented tropical forest landscapes worldwide

Gargalos nas cadeias de produção.

Introdução. Antes da Fazenda. Defensivos químicos e biológicos no Brasil. Fertilizantes e corretivos. Biotecnologia, Softwares agricultura digital/ precisão. Conectividade e a falta de comunicação de dados nas propriedades rurais. Dentro da Fazenda. Custos de produção e melhoria do pacote tecnológico. Depois da Fazenda. Comercialização nacional e internacional. Temas Transversais. Falta de energia de qualidade nas propriedades rurais. Rastreabilidade. Aspectos da logística. Capacitação e extensão rural

Perfil dos pequenos e médios produtores em relação à adoção de tecnologias do Agro 4.0.

Introdução. Perfil do agricultor familiar e análise territorial das dinâmicas recentes no meio rural brasileiro: em busca da formulação de novas orientações para as ações de assistência técnica e extensão rural - ATER. Migrações entre públicos: concentração produtiva e fragmentacão de estabelecimentos. Análise das cadeias produtivas: observações e projeções para 2030. Possíveis causas da fragmentação de estabelecimentos e concentração produtiva. Uma nova configuração de produtores. Novo rural, novos desafios para políticas públicas. Ater 5.

Potential of a Brazilian sedimentary zeolite use in agriculture and livestock.

The use of minerals for agricultural purposes is becoming widespread, and zeolites have a special niche in this category since can play an important role in the nanotechnology era. Zeolites have three main properties, which are of great interest for agricultural purposes: high cation exchange capacity, high water holding capacity in the free channels, and high adsorption capacity. In Brazil, sediment occurrences of this aluminosilicate are known to exist in northern areas of Brazil. Zeolites improves the efficiency of nutrient use by increasing the availability of P from phosphate rock, the utilization of N and reduced losses by leaching of exchangeable cations. Zeolites mixed with phosphate rock, can act as controlled delivery system and renewable source of nutrients for plants. The increased efficiency of N utilization when urea is used together with zeolite was demonstrated that achieved increasing of N use efficiency, N uptake and dry matter yield and reductions of losses by ammonia volatilization. Zeolites also improve the efficiency of water use by increasing the soil water holding capacity and its availability to plants. While literature shows that zeolites are useful for increasing nutrient use efficiency in a range of crops, few information exists on the use of stilbite, Brazilian specie of zeolite, on agricultural systems especially on acid soils. The objective of this report was to characterize and test the application of the Brazilian zeolitic sedimentary rock as slow release fertilizer, soil conditioner and animal nutrition supplement. Characterization analyses demonstrate that the zeolitic sediment and quartz are the major components of the head samples from Brazilian zeolite deposits. The head sample contained zeolite stilbite mixed with smectitic clay deposits. A characterization with X-Ray diffraction showed the presence of stilbite ((Na,K)Ca2[Al5Si13O36] .14H2O). The slow-release fertilizer effects of zeolite are a result of ion-exchange reactions with the zeolite, or through a combination of ion-exchange and mineral-dissolution reactions. Results of the successive crops of lettuce, tomato, rice and Andropogon grass carried out on the same substrate of each pot indicated that N, P and K enriched zeolite was an adequate slow-release source of nutrients to plants. The experiment also demonstrated the enhanced of P availability from phosphate rock when applied in combination with zeolite, though the P availability presented a trend of increasing, especially at after the second and third crops unlike the soluble P source. The supply of nutrients through the mineral zeolite enriched with NPK added to the organic substrate was a viable alternative for Rangpur lime citrus rootstock production in protecting environment since significantly increased dry matter production, height and steam diameter. Evaluation of the mixture of urea and zeolite to avoid ammonia volatilization in pot with soil and Tanzania-grass pasture was evaluated. The smallest losses by volatilization occurred at the proportions of the mixture of 25% of zeolite to urea and lead to losses reduction from 33.5 to 7.6 kg/ha. Zeolites are also an alternative to improve soil water retention when used as soils amendments. The increase in water retention curve with zeolite amendment and the on available water capacity were 10, 38 and 67% and easily available water increased 15, 51 and 111% in relation to the control respectively with the use of 33.3; 66.7 and 100.0 g/kg of zeolite. The supplementation of zeolite and urea may regulate the ammonia release in the rumen allowing the continuous synthesis of cellular protein. Lambs feed with 0, 2,5; 5 and 7,5% of zeolite increased weight gain. The present results indicate that despite their high-impurity content; applications of natural Brazilian zeolitic concentrates in the agriculture present no major obstacle. And the addition of the zeolite - stilbite concentrate should increase the agronomic efficiency of fertilizer and animal performance