A strategic evaluation of the introduction of the East Friesian sheep breed on a North Island hill country farm : a thesis submitted in partial fulfilment of the requirements for the degree of Masters in Applied Science in Agricultural Systems and Management at Massey University

New Zealand sheep fanning has changed dramatically over the past 20 years as it has adjusted to a market-led and unsubsidised economy. Despite this, new technology and management practices such as cross breeding offer exciting opportunities for improving sheep industry profitability. The introduction of new genetic material into the sheep flock can provide benefits through improved productivity and product attributes but it may also have negative consequences for industry growth if used incorrectly. The advantages of introducing a new sheep breed to a farm are usually widely published but not necessarily well researched. The East Friesian (EF) was made available to farmers in autumn 1996. It has a reputation for being highly fertile, a good milk producer and heavy-weight-lamb producer. However, no research has been published on how to develop a profitable management strategy for adopting EF's onto a hill country property. The purpose of this study was to test the hypothesis that the EF would improve the productivity and profitability of a lower North Island hill country farm. A case farm analysis using the STOCKPOL farm simulation model was used to compare the productivity and profitability of the current Romney (Rn x Rn) flock with either an East Friesian (EF) x Rn crossbred flock or a purebred EF x EF flock. The STOCKPOL model was calibrated to simulate the existing sheep and beef cattle policy for the 324 ha hill country farm, Tuapaka. Pasture growth rate data were adjusted to sustain the reordered levels of animal production and establish a basis against which the EF x Rn and EF x EF flocks could be compared. The cattle policy was fixed for all options. Ewe numbers, with a 20 % replacement rate, were adjusted for the live weight profiles and production levels of the EF x Rn (67 kg at mating; 148 lambs born: 100 ewes mated) and EF x EF (80 kg at mating; 230 lambs born: 100 ewes mated) breeds until the farm system was just biologically feasible. This indicated 1315 EF x Rn sheep or 909 EF x EF could be farmed compared to 1930 Romneys (52 kg; 117 lambs born: 100 ewes mated). In stock unit terms (SU) the EF x Rn was 1.25 and the EF x EF 1.54 compared to the Rn x Rn ewe (1.00) which consumed 526 kgDM per year. The STOCKPOL outputs were copied into an enterprise margin (EM) format and the profitability of the sheep breeds calculated after adjusting for the cost of capital (CoC) of sheep wintered. The EM's (per ha) were $324,$340 and $351 for the Rn x Rn, EF x Rn and EF x EF breeds, respectively. The EF x EF was the preferred option for all risk preferences. A sheep age structure model was developed to simulated the transition to an EF x Rn crossbred flock. This took six years. The additional net present value (NPV) in 1998 dollars of the EF x Rn vs. the Rn x Rn was$ 92,133. The transition to a purebred EF flock would take 24 years if a grading up strategy were adopted. An important finding was the breed x pasture production interaction. Annual pasture consumption was 869 t DM for the Rn x Rn flock, 780 t DM for the EF x Rn policy and 647 t DM for the EF x EF flock. Reduced pasture production occurred because of the higher lamb:ewe ratio of the EF sheep contributed to increased pasture senescence and decay in the summer and autumn. Ways to prevent this occurring need to be explored through further modelling studies using STOCKPOL and by evaluating the experience of famers who have adopted EF's. The study confirmed the hypothesis: EF sheep would improve production and profit on the hill country case farm. Recent farmer experience with the East Friesian should now be evaluated against this result. Title: A strategic evaluation of the introduction of the East Friesian sheep breed on a North Island hill country farm. Author: Jesus Romero Martinez Year: 1998 Degree: MApplSc (Agricultural Systems and Management)

Null boundary controllability of a 1-dimensional heat equation with an internal point mass

We consider a linear hybrid system composed by two rods of equal length connected by a point mass. We show that the system is null controllable with Dirichlet and Neumann controls. The results are based on a careful spectral spectral analysis together with the moment method.Comment: 12 pages, typos corrected, added references, matches version to be submitted to Systems and Control Letter

Improved construction of irregular progressive edge-growth Tanner graphs

The progressive edge-growth algorithm is a well-known procedure to construct regular and irregular low-density parity-check codes. In this paper, we propose a modification of the original algorithm that improves the performance of these codes in the waterfall region when constructing codes complying with both, check and symbol node degree distributions. The proposed algorithm is thus interesting if a family of irregular codes with a complex check node degree distribution is used.Comment: 3 pages, 3 figure

Blind Reconciliation

Information reconciliation is a crucial procedure in the classical post-processing of quantum key distribution (QKD). Poor reconciliation efficiency, revealing more information than strictly needed, may compromise the maximum attainable distance, while poor performance of the algorithm limits the practical throughput in a QKD device. Historically, reconciliation has been mainly done using close to minimal information disclosure but heavily interactive procedures, like Cascade, or using less efficient but also less interactive -just one message is exchanged- procedures, like the ones based in low-density parity-check (LDPC) codes. The price to pay in the LDPC case is that good efficiency is only attained for very long codes and in a very narrow range centered around the quantum bit error rate (QBER) that the code was designed to reconcile, thus forcing to have several codes if a broad range of QBER needs to be catered for. Real world implementations of these methods are thus very demanding, either on computational or communication resources or both, to the extent that the last generation of GHz clocked QKD systems are finding a bottleneck in the classical part. In order to produce compact, high performance and reliable QKD systems it would be highly desirable to remove these problems. Here we analyse the use of short-length LDPC codes in the information reconciliation context using a low interactivity, blind, protocol that avoids an a priori error rate estimation. We demonstrate that 2x10^3 bits length LDPC codes are suitable for blind reconciliation. Such codes are of high interest in practice, since they can be used for hardware implementations with very high throughput.Comment: 22 pages, 8 figure

Untainted Puncturing for Irregular Low-Density Parity-Check Codes

Puncturing is a well-known coding technique widely used for constructing rate-compatible codes. In this paper, we consider the problem of puncturing low-density parity-check codes and propose a new algorithm for intentional puncturing. The algorithm is based on the puncturing of untainted symbols, i.e. nodes with no punctured symbols within their neighboring set. It is shown that the algorithm proposed here performs better than previous proposals for a range of coding rates and short proportions of punctured symbols.Comment: 4 pages, 3 figure