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’

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

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

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

Emerging imaging techniques in spondyloarthritis dual-energy computed tomography and new MRI sequences

Imaging of the sacroiliac joint plays a critical role in the classification of patients with axial spondyloarthritis. New imaging techniques are emerging, changing the way clinicians look at the sacroiliac joint. This article introduces the novel techniques in imaging of spondyloarthritis, including dual-energy computed tomography and new MRI sequences, with a focus on the imaging of bone marrow edema and erosions of the sacroiliac joint

A New Dantzig-Wolfe Reformulation And Branch-And-Price Algorithm For The Capacitated Lot Sizing Problem With Set Up Times

The textbook Dantzig-Wolfe decomposition for the Capacitated LotSizing Problem (CLSP),as already proposed by Manne in 1958, has animportant structural deficiency. Imposingintegrality constraints onthe variables in the full blown master will not necessarily givetheoptimal IP solution as only production plans which satisfy theWagner-Whitin condition canbe selected. It is well known that theoptimal solution to a capacitated lot sizing problem willnotnecessarily have this Wagner-Whitin property. The columns of thetraditionaldecomposition model include both the integer set up andcontinuous production quantitydecisions. Choosing a specific set upschedule implies also taking the associated Wagner-Whitin productionquantities. We propose the correct Dantzig-Wolfedecompositionreformulation separating the set up and productiondecisions. This formulation gives the samelower bound as Manne'sreformulation and allows for branch-and-price. We use theCapacitatedLot Sizing Problem with Set Up Times to illustrate our approach.Computationalexperiments are presented on data sets available from theliterature. Column generation isspeeded up by a combination of simplexand subgradient optimization for finding the dualprices. The resultsshow that branch-and-price is computationally tractable andcompetitivewith other approaches. Finally, we briefly discuss how thisnew Dantzig-Wolfe reformulationcan be generalized to other mixedinteger programming problems, whereas in theliterature,branch-and-price algorithms are almost exclusivelydeveloped for pure integer programmingproblems.branch-and-price;Lagrange relaxation;Dantzig-Wolfe decomposition;lot sizing;mixed-integer programming