Conference pears; work on system changes to enable better scab control in organic orchards in the Netherlands

Scab control in Conference pears is the bottleneck in organic growing. A group of growers, advisers and researchers in the Netherlands is working on new approaches to organic pear growing. Central to this approach is a reliable and good scab control. Changes in the system of cultivation are sought which will enable this scab control with less fungicide. This has become even more urgent since copper was banned as a fungicide in the Netherlands. First results from trials on vigour control show that there is potency for system changes that will enable a better scab control in organic growing. Scab incidence was reduced in three trials with 34, 58 and 82% respectively. The project, in which also other cultivation measures are being tested, will be continued

Fruit quality of Elstar en Santana in the Netherlands

The growth of the market for Dutch organic apples is disappointing. Especially the large-scale introduction in the supermarket channel is not happening as fast as many hoped. One of the explanations given is that there is a gap between the quality as produced and the quality as expected by the retailers. In a three year project the Louis Bolk Institute together with many other partners in the sector have tried to facilitate talks on apple quality between actual partners in the different chains from producer till retailer. During this period we monitored the quality of Elstar and Santana on many farms and on the shelf in the different outlets. This has given us detailed information about the current quality of Dutch organic apples. Presented here are some preliminary results of the monitoring at the farms. The project will end mid 2004, final results will be published by the end of the year. Progress of the project can be followed through the website www. louisbolk. nl/projects/fruit/’classy apples’

Solving Lotsizing Problems on Parallel Identical Machines Using Symmetry Breaking Constraints

Production planning on multiple parallel machines is an interesting problem, both from a theoretical and practical point of view. The parallel machine lotsizing problem consists of finding the optimal timing and level of production and the best allocation of products to machines. In this paper we look at how to incorporate parallel machines in a Mixed Integer Programming model when using commercial optimization software. More specifically, we look at the issue of symmetry. When multiple identical machines are available, many alternative optimal solutions can be created by renumbering the machines. These alternative solutions lead to difficulties in the branch-and-bound algorithm. We propose new constraints to break this symmetry. We tested our approach on the parallel machine lotsizing problem with setup costs and times, using a network reformulation for this problem. Computational tests indicate that several of the proposed symmetry breaking constraints substantially improve the solution time, except when used for solving the very easy problems. The results highlight the importance of creative modeling in solving Mixed Integer Programming problems.Mixed Integer Programming;Formulations;Symmetry;Lotsizing

Uniqueness Of Larval Releasing Of Littoraria Scabra L. (Gastropoda: Littorinidae), In Tombariri Mangrove, North Sulawesi,Indonesia

Penelitian yang amat langka di alam ini menemukan kebaharuan keunikan strategi reproduksi Littoraria. scabra, di waktu kopulasi jantan berperan seks terbalik menyedot sebagian telur yang dibuahi dan dierami telur-telur yang dibuahi dalam tubuhnya sampai menetas menjadi larva-larva serta melepaskan larva-larva tersebut di bulan penuh dan baru yang mengikuti siklus pasang selama penelitian. Temuan amat langka kedua keunikan strategi reproduksi L. scabra, yang amat langka di alam dengan pasangan jantan-betina lagi kawin melepaskan larva-larva baik jantan maupun betina pada siklus bi-lunar bersamaan dengan siklus pasang selama penelitian

The Role of National Parliaments in European Decision-Making

National parliaments can be considered as victims of the European integration process. National parliaments ceded legislative powers to the EU and often lost leverage over their national executive branch, which continued to play a central role in EU decision-making. Different domestic parliamentary scrutiny systems have been established to enhance parliamentary involvement and control over EU affairs. In 2006 the Barroso Commission provided an additional impetus for parliaments to get involved, by offering to transmit its policy proposals directly to national parliaments with an open invitation to comment on them. The Lisbon Treaty foresees the possibility that national parliaments carry out subsidiarity checks on policy proposals. This paper argues that the different national and European provisions for parliamentary involvement do not amount to much. However, if we consider the combined effect of the different avenues in a dynamic perspective, they might jointly trigger a reassertion of national parliamentary influence in the European policy process

Stop the Integration Principle?

Lord Slynn of Hadley is probably not primarily known as an environmental lawyer. His contributions to the development of European environmental law are, however, considerable. On May 24, 1988, Slynn delivered his famous opinion in the so-called Danish Bottles case. In that case, the European Court of Justice ( ECJ ) held that a system requiring manufacturers and importers to market beer and soft drinks only in reusable containers (which had to be approved by a National Agency for the Protection of the Environment) was subject to what is now article 34 of the Treaty on the Functioning of the European Union ( TFEU ) since the Lisbon Treaty entered into force. The importance of this judgment is that it enabled and facilitated the integration of environmental considerations into the market freedoms of the European Community (later the European Union). This Essay, in memory of Lord Slynn of Hadley, is therefore devoted to the process of integrating environmental requirements in other areas

Family relations, children and interregional mobility, 1970 to 2000

During the last three decades, there has been a rapid increase in female labor force participation rates. This increase has gradually changed the family concept. Today, women and men both work and contribute to family earnings so that dual-earner households has become the rule rather the single-earner households. A popular view is that the growth in female labor supply has reduced the incentives to migrate for families were both spouses work. With both spouses working migration decisions becomes a rather complicated process. In particular if both spouses are to find new jobs, regions has to be diversified enough to offer career opportunities for both spouses. Children are generally supposed to trigger local migration, but to decrease long distance migration. The objective of this paper is to examine how family formation, the arrival of children and family dissolution has influenced migration rates during the period 1970-2000. Determinants of migration are analyzed using Cox proportional hazard regressions. The empirical analysis is based on the longitudinal database LINDA expanded with information on births for children and when geographical moves took place in time. According to the results family formation, the presence of children and family dissolutions has all been important for the interregional migration patterns in Sweden during the last three decades. The presence of family ties thereby seems to be of vital importance for the decision to migrate. The findings indicate that family formation and presence of children lowers the propensity for migration while family dissolution seems to trigger migration. Furthermore, the estimations indicate that migration propensities have decreased over the three last decades. This finding might be related to the rapid increase in female labor force participation rates during the observed period.Family relations; migration rates 1970-2000

Disease management in organic apple orchards is more than applying the right product at the correct time

The relative importance of diseases on apple is varying with cultivar, management, time, and climate. Many aspects of the cropping system influence the development of diseases. The choice of the variety determines the disease management during the lifetime of the orchard. Cultural practices improve the growth and nutrial status of the tree, and therewith influence the susceptibility of the plant and fruits to diseases directly. Prolonged growth can also have an indirect effect by causing a microclimate and growing pattern that favours infection of tree, leafs and fruits by various diseases. Sanitation measures are common practise for most organic fruit growers and help to make other measures more effective by reducing infection inoculums. Despite all preventive measures, disease control in organic orchards at an economically feasible level still largely depends on the application of fungicides. Measures that allow reduction of fungicidal applications on key diseases, lead to the development of a secondary disease complex that can cause severe losses when not managed effectively and make a well thought-out control strategy necessary. In research, advisory and practical decision making, disease management in organic orchards should always be seen in the perspective of the management of the total growing system. With all factors that contribute to disease management in organic orchards optimized, we are able to successfully implement new materials and methods that may not be as effective as common fungicides in themselves, but add to the effectiveness of the disease management system as a whole. This total system approach makes organic fruit growing what it is

Improved Lower Bounds For The Capacitated Lot Sizing Problem With Set Up Times

We present new lower bounds for the Capacitated Lot Sizing Problem with Set Up Times. We improve the lower bound obtained by the textbook Dantzig-Wolfe decomposition where the capacity constraints are the linking constraints. In our approach, Dantzig-Wolfe decomposition is applied to the network reformulation of the problem. The demand constraints are the linking constraints and the problem decomposes into subproblems per period containing the capacity and set up constraints. We propose a customized branch-and-bound algorithm for solving the subproblem based on its similarities with the Linear Multiple Choice Knapsack Problem. Further we present a Lagrange Relaxation algorithm for finding this lower bound. To the best of our knowledge, this is the first time that computational results are presented for this decomposition and a comparison of our lower bound to other lower bounds proposed in the literature indicates its high quality.Lagrange relaxation;Dantzig-Wolfe decomposition;capacitated lot sizing;lower bounds