Abstract: The aim of this study was to determine how often rural farmers in a watershed use no-tillage systems combined with crop rotation, contour farming and agricultural terraces. The study area was Paraná Watershed III (PB3) in the western region of Paraná State, and data from the 2006 Agricultural Census of the Brazilian Institute of Geography and Statistics were used. A frequency distribution analysis of farms as a function of the no-tillage (NT) area was conducted in combination with a cluster analysis of soil and water conservation practices (adoption of crop rotation, contour farming and agricultural terrace practices). The results showed that the farms in PB3 adopt adequate soil and water conservation practices, with 73% adopting NT combined with at least 2 other conservation practices; however, agricultural terracing was found to be the most neglected practice in the region. In addition, based on the soil and water conservation practices in the watershed, 5 groups of farms were identified, the worst of which, those located in the municipalities that mainly neglect conservation practices, live in areas with highly erodible soils.

ABSTRACT Retaining sugarcane straw over the soil after harvesting can improve soil structure and increase soil carbon stabilization, mainly in macroaggregates. We evaluated the carbon content in the aggregate classes in areas under burn and no-burn (adopted for five years) sugarcane management systems, focusing on the superficial layer (0.00-0.20 m). The experiment was carried in an Oxisol and the treatments consisted in burnt sugarcane, manual harvest; burnt sugarcane, mechanized harvest; and no-burn, mechanized harvest. The retention of sugarcane straw on the soil surface is justified by the increase in carbon content and carbon stock in the surface layer (0.00-0.20 m) by restructuring of the soil, even though it cannot match the structure of the soil under native forest. Our results suggest that in no-burn management the carbon not occluded inside aggregates was important to increase carbon stabilization in soil and that more attention should be given to macroaggregates 2.00-8.00 mm present in this management system, that showed higher carbon content and was responsible for increase of the geometric and weight diameter, increasing the erosion resistance in the long term in relation to burn systems.

Neste artigo apresenta-se uma nova heurística para a determinação de rotas para veículos, aplicada a uma empresa portuguesa de distribuição de produtos alimentares. Esta empresa é detentora de uma grande carteira de clientes, realizando perto de cento e trinta entregas diárias de vários tipos de produtos. A necessidade da automatização do processo de determinação das rotas dos veículos surge naturalmente neste contexto. Esta nova heurística composta tem uma fase construtiva, uma fase de optimização local e uma fase de pós-optimização, sendo o objectivo a minimização do tempo total dos percursos. São ainda incorporadas restrições adicionais derivadas da aplicação concreta que motivou o presente trabalho. Em particular são consideradas janelas temporais, quer para os condutores/veículos quer para os clientes, e recolhas de vasilhame em simultâneo com as entregas de mercadorias.

In this paper a new heuristic for the vehicle routing problem is presented. This algorithm was applied to a problem originated from a Portuguese alimentary products distribution company. This company has many clients and more then 130 deliveries per day for all products. When considering these figures, the vehicle routing problem becomes too much complex to be manually solved. The necessity of automatization naturally arises. This new multi-phase heuristic has a constructive phase, a local optimisation phase and a pos-optimisation phase, and aims the minimization of the sum of the routes total time. Additional constraints to the vehicle routing problem, driven by the particular company that motivated this work, are considered. In particular time-windows both for the drivers and for the clients and pick-up together with deliveries are considered.

Este artigo aborda o problema de posicionamento de objetos de base circular (tubos, rolos, ...) sobre uma base retangular de maiores dimensões. Por razões práticas, considera-se que todos os objetos a carregar apresentam a mesma altura. A resolução do problema consiste na determinação do padrão de posicionamento das bases circulares dos referidos objetos sobre a base de forma retangular, tendo como objetivo a maximização do número de objetos estritamente posicionados no interior dessa base. Este padrão de posicionamento será repetido em cada uma das camadas a carregar sobre a base retangular. Apresentam-se dois algoritmos para a resolução do problema. Estes algoritmos baseiam-se numa meta-heurística, Simulated Annealling, cuja afinação de parâmetros requereu a execução de testes intensivos com o objetivo de atingir um elevado grau de eficiência no seu desempenho. As características dos algoritmos implementados permitiram que a sua extensão à consideração de círculos com raios diferentes fosse facilmente conseguida.

This paper is motivated by the problem of loading identical items of circular base (tubes, rolls, ...) into a rectangular base (the pallet). For practical reasons, all the loaded items are considered to have the same height. The resolution of this problem consists in determining the positioning pattern of the circular bases of the items on the rectangular pallet, while maximizing the number of items. This pattern will be repeated for each layer stacked on the pallet. Two algorithms based on the meta-heuristic Simulated Annealing have been developed and implemented. The tuning of these algorithms parameters implied running intensive tests in order to improve its efficiency. The algorithms developed were easily extended to the case of non-identical circles.