Competition and complementarity between road and rail transport in the carriage of freight

A seminar on competition and complementarity between road and rail transport in the carriage of freight was conducted at ECLAC Headquarters on 6-7 November 2001. The seminar was attended by experts on transport matters from a range of countries, and their presentations covered the current state of integration of transport in countries like Argentina, Brazil, Chile and Mexico. Also in attendance was an expert from Central America, who spoke about modal integration of freight transport in that region. Three round-table discussions were held with the participation of representatives of the trucking and rail sectors, drawn from both the private and public spheres.

Competition Policy and Trade Agreements in the Region: Exploring Forums for Cooperation and Convergence

The similarities of competition provisions in integration and other intraregional agreements and the dissemination of this information could serve as a basis for progress in cooperation and convergence on this issue in the region. The negotiation processes that have taken place for these agreements have also enhanced communication between the national agencies concerned, leading to processes of learning and harmonization; these processes could be strengthened as part of the current efforts of administrating and implementing trade agreements. This edition of the FAL Bulletin reviews the information available in order to see how progress can be made on this issue on the basis of the analysis and bibliography of Álvarez and others (2006), and Silva and Álvarez (2006).

Estudo fitossociológico e interferência das plantas daninhas na nutrição e produtividade do quiabeiro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Nutrients distribution in diseased coffee leaf tissue

Knowing the structure and distribution of nutrients in plant tissues can clarify some mechanisms of pathogen attack in plants and plant defense against infection, thus helping management strategies. The aim of this study was verify differences in distribution of mineral nutrients in coffee leaf tissues around foliar lesions of bacterial blight of coffee, blister spot, cercospora leaf, phoma leaf spot and coffee leaf rust. Fragments of leaf tissue surrounding the lesions were dehydrated in silica gel, carbon covered and subjected to X-ray microanalysis (MAX). Thirty-three chemical elements were detected in leaf tissue; however, there was variation in potassium and calcium contents surrounding the lesions. The highest potassium content was found in asymptomatic tissues surrounding the lesions, decreasing toward the transition zone and reaching minimum content in symptomatic tissues. The highest calcium content was found in symptomatic tissues, decreasing toward the transition zone and reaching minimum content in asymptomatic tissues. Therefore, MAX can be used to analyze the composition and distribution of nutrients in plant tissues and, if associated with mineral nutrition, it may help understand host-pathogen relationships and plant disease management.

Nutrients in Amazonian Black Earth from Caxiuanã Region

Padrões de dispersão de nutrientes em terra preta Amazônica (TPA) podem dar informações sobre atividades antrópicas dos habitantes da Amazônia. Estudos sobre pH, fósforo disponível (P), matéria orgânica (MO) e os cátions trocáveis, Ca²⁺ e Mg²⁺, foram realizados em amostras de solos dos horizontes A₁ e A₂ ao longo de uma área com TPA (norte-sul e leste-oeste) em um sítio arqueológico denominado Ilha de Terra, na Unidade de Conservação Floresta Nacional de Caxiuanã, Município de Melgaço, Brasil. Os resultados indicaram que a MO e o Ca são os que apresentam maior dispersão. Correlações mais elevadas foram encontradas entre OM-Ca-Mg às proximidades da área central e levam a inferir que a dispersão geoquímica de MO, Ca, Mg e P em sítios arqueológicos com TPA está relacionada com atividades humanas pregressas.

Substâncias húmicas: interações com nutrientes e contaminantes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Nonlinear dynamics of within-host parasite competition

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Cycling of nutrients and silicon in pigeonpea and pearl millet monoculture and intercropping

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

Ecological competition and the incidence of Acinetobacter baumannii bloodstream infections in a teaching hospital in Southeastern Brazil

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

Early selection in open-pollinated Eucalyptus families based on competition covariates

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

Cerrado vegetation and global change: the role of functional types, resource availability and disturbance in regulating plant community responses to rising CO2 levels and climate warming

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effects of litter manipulation in a tropical Eucalyptus plantation on leaching of mineral nutrients, dissolved organic nitrogen and dissolved organic carbon

Although many studies have shown that soil solution chemistry can be a reliable indicator of biogeochemical cycling in forest ecosystems, the effects of litter manipulations on the fluxes of dissolved elements in gravitational soil solutions have rarely been investigated. We estimated the fluxes of NH4-N, NO3-N, K, Ca, Mg, Na, Cl, dissolved organic nitrogen (DON) and dissolved organic carbon (DOC) over the first two years after re-planting Eucalyptus trees in the coastal area of Congo. Two treatments were replicated in two blocks after clear-cutting 7-year-old stands: in treatment R, all the litter above the mineral soil was removed before planting, and in a double slash (DS) treatment, the amount of harvest residues was doubled. The soil solutions were sampled down to a depth of 4 m and the water fluxes were estimated using the Hydrus 1D model parameterized from soil moisture measurements in 4 plots. Isotopic and spectroscopic analytical techniques were used to assess the changes in dissolved organic matter (DOM) properties throughout the transfer in the soil. The first year after planting, the fluxes of NH4-N, K, Ca, Mg, Na, Cl and DOC in the topsoil of the DS treatment were 2-5 times higher than in R, which showed that litter was a major source of dissolved nutrients. Nutrient fluxes in gravitational solutions decreased sharply in the second year after planting, irrespective of the soil depth, as a result of intense nutrient uptake by Eucalyptus trees. Losses of dissolved nutrients were noticeably low in these Eucalyptus plantations despite a low cation exchange capacity, a coarse soil texture and large amounts of harvest residues left on-site at the clear cut in the DS treatment. All together, these results clarified the strong effect of litter manipulation observed on eucalypt growth in Congolese sandy soils. DOM fluxes, as well as changes in delta C-13, C:N and aromaticity of DOM throughout the soil profile showed that the organic compounds produced in the litter layer were mainly consumed by microorganisms or retained in the topsoil. Below a depth of 15 cm, most of the DOC and the DON originated from the first 2 cm of the soil and the exchanges between soil solutions and soil organic matter were low. (C) 2014 Elsevier B.V. All rights reserved.

Effects of Temperature on Intraspecific Competition in Ectotherms

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