Growth medium and environmental studies of sweet potato meristem culture : a thesis presented in partial fulfilment of the requirements for the degree of Master in Applied Science at Massey University, New Zealand

The ability of three New Zealand local sweet potato (Ipomoea batatas L.) cultivars 'Toka Toka Gold', 'Beauregard', and Owairaka Red' to form plantlets in vitro was investigated Meristematic tips (0.2–0.4 mm) of apical shoots from vines of the three cultivars, and from tubers of 'Owairaka Red' were cultured in modified Murashige and Skoog (1962) medium (MS medium) containing plant growth regulator (s). Cultivars and organs of explants differed in response to exogenous levels of plant growth regulator(s) and in the rate of proliferation. Optimal regeneration occurred in liquid MS medium supplemented with BA 0.1 mg/1 for 'Toka Toka Gold' and Owairaka Red' (from vines), and with BA 0.5 + IBA 0.1 mg/1 for 'Beauregard'. For Owairaka Red' (from tubers), MS liquid medium with BA 0.3 mg/1, and MS liquid medium with GA3 20 mg/1 (plus other organic compounds) proliferated shoots and plantlets. Continuous lighting inhibited the proliferation of plantlets in all three cultivars. Regeneration was strongly affected by the age of the shoots from which the explants were excised and the season when cultures were begun. Successful culture was obtained by culturing explants from young shoots in the Spring

Capitalizing R&D Expenditures

The next international version of the System of National Accounts will recommend that R&D (Research and Development) expenditures be capitalized instead of being immediately expensed as in the present System of National Accounts 1993. An R&D project creates a new technology, which in principle does not depreciate like a reproducible asset. A new technology is however subject to obsolescence, which acts in a manner that is somewhat similar to depreciation. The paper looks at the net benefits of an R&D project in the context of a very simple intertemporal general equilibrium model and suggests that R&D expenditures be amortized using the matching principle that has been developed in the accounting literature to match the fixed costs of a project to a stream of future benefits. Of particular interest is the evaluation of the net benefits of a publicly funded project where the results are made freely available to the public.Cost benefit analysis, R&D project, intertemporal general equilibrium theory, money metric utility scaling, matching principle, amortization, deprecia

Distance Preserving Graph Simplification

Large graphs are difficult to represent, visualize, and understand. In this paper, we introduce "gate graph" - a new approach to perform graph simplification. A gate graph provides a simplified topological view of the original graph. Specifically, we construct a gate graph from a large graph so that for any "non-local" vertex pair (distance higher than some threshold) in the original graph, their shortest-path distance can be recovered by consecutive "local" walks through the gate vertices in the gate graph. We perform a theoretical investigation on the gate-vertex set discovery problem. We characterize its computational complexity and reveal the upper bound of minimum gate-vertex set using VC-dimension theory. We propose an efficient mining algorithm to discover a gate-vertex set with guaranteed logarithmic bound. We further present a fast technique for pruning redundant edges in a gate graph. The detailed experimental results using both real and synthetic graphs demonstrate the effectiveness and efficiency of our approach.Comment: A short version of this paper will be published for ICDM'11, December 201

Indecomposable representations and oscillator realizations of the exceptional Lie algebra G_2

In this paper various representations of the exceptional Lie algebra G_2 are investigated in a purely algebraic manner, and multi-boson/multi-fermion realizations are obtained. Matrix elements of the master representation, which is defined on the space of the universal enveloping algebra of G_2, are explicitly determined. From this master representation, different indecomposable representations defined on invariant subspaces or quotient spaces with respect to these invariant subspaces are discussed. Especially, the elementary representations of G_2 are investigated in detail, and the corresponding six-boson realization is given. After obtaining explicit forms of all twelve extremal vectors of the elementary representation with the highest weight {\Lambda}, all representations with their respective highest weights related to {\Lambda} are systematically discussed. For one of these representations the corresponding five-boson realization is constructed. Moreover, a new three-fermion realization from the fundamental representation (0,1) of G_2 is constructed also.Comment: 29 pages, 4 figure