An investigation of factors contributing to extended storage life of meat products for the tropics : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Meat Technology at Massey University

A combination of factors which could extend the shelf­ life of minced mutton meat during storage under warm conditions (30 °c) while still maintaining a low cost product with acceptable sensory and microbiological properties was investigated. The combination of factors studied involved pH values from 5. 5 to 3. 5 achieved by the addition of acetic acid, water activity ( a w ) values from 0. 9 9 to 0. 91 achieved by the addition of sorbitol and the reduction in moisture contents, heat treatments from 30 to 50 0 C, and the use of different packaging materials (cellulose, polyethylene and aluminium foil films). It was expected (from reported work) that stability would be achieved by reducing aw to 0. 95 and pH to 5. 2, but at 30° C the shelf-life was less than one week. Within the limits of the values that were considered, the control of pH was the only significant factor in extending the shelf-life of minced mutton meat stored at 30° C. To achieve a commercial acceptable shelf-life of 8 weeks, a pH of 4. 1 or below was required. Minced mutton with the pH of 4.1 can be organoleptically acceptable with the addition of the right combinations of spices and seasonings suited to specific localities and countries. The practical value of lowering the pH of meat products below 4.1 must be questioned because no additional microbiological protection will be obtained and the increase of the acid level will only decrease the flavour acceptance. Combinat­ions of low acid and spices and seasonings would appear to be a development area of greater promise for tropical countries than intermediate moisture meat

Private investment in Mexico : an empirical analysis

In 1985, Mexico shifted to a growth strategy based on private investment and exports rather than on import substitution and public sector investment. The policy implications of this study, are that to increase investment, Mexico should follow policies aimed at reducing investment adjustment costs and increasing factor mobility and credibility in the program of structural reforms, rather than at subsidizing investment.Economic Stabilization,International Terrorism&Counterterrorism,Economic Theory&Research,Environmental Economics&Policies,Macroeconomic Management

Pensions and Saving: New International Panel Data Evidence.

This paper contributes to the empirical literature on pensions and saving by studying the influence of funded pension systems on the gross national saving rate using a sample of 48 developed and developing countries over the 1980-2004 period. To the best of our knowledge, this updated database –which builds on the one assembled by Lopez Murphy and Musalem (2004)- is the largest on pension funds stocks and flows. Our panel data econometric results suggest that a one-dollar increase in pension saving increases national saving by between 0 and 20 cents. The structure of the system in terms of mandatory participation and portfolio composition does not affect the results, but the maturity of the system does seem to be a robust driver of national saving, inducing an increase of the saving rate of 0.3-0.5 percentage points for each additional year of existence. Reforming countries does not seem to have attained higher saving rates than others. Concerning other saving drivers, the old age dependency ratio and the urbanization ratio (even though the latter loses significance in some regressions) were negatively correlated with saving, while GDP growth, inflation, the terms of trade, and the current account displayed a positive sign. In terms of saving projections, the rather declining trend in pension saving implies that this is unlikely to boost the national saving rate, but the rising old age dependency ratio might cause, over a 25-year time horizon, a fall in the saving rate of 2.1 and 3.3 percentage points in OECD and non-OECD countries, respectively.

The origins of early modern experimental philosophy

This paper argues that early modern experimental philosophy emerged as the dominant member of a pair of methods in natural philosophy, the speculative versus the experimental, and that this pairing derives from an overarching distinction between speculative and operative philosophy that can be ultimately traced back to Aristotle. The paper examines the traditional classification of natural philosophy as a speculative discipline from the Stagirite to the seventeenth century; medieval and early modern attempts to articulate a scientia experimentalis; and the tensions in the classification of natural magic and mechanics that led to the introduction of an operative part of natural philosophy in the writings of Francis Bacon and John Johnston. The paper concludes with a summary of the salient discontinuities between the experimental/speculative distinction of the mid-seventeenth century and its predecessors and a statement of the developments that led to the ascendance of experimental philosophy from the 1660s

The nuclear pseudospin symmetry along an isotopic chain

We investigate the isospin dependence of pseudospin symmetry in the chain of tin isotopes (from $^{120}$Sn until $^{170}$Sn). Using a Woods-Saxon parametrization of the nuclear potential for these isotopes we study in detail the effect of the vector-isovector $\rho$ and Coulomb potentials in the energy splittings of neutron and proton pseudospin partners in the isotopic chain. We conclude that the realization of nuclear pseudospin symmetry does not change considerably with the mass number, and is always favored for neutrons. We also find that the $\rho$ potential accounts for essentially all the pseudospin isospin asymmetry observed and that the Coulomb potential plays a negligible role in this asymmetry. This can be explained by the dynamical nature of pseudospin symmetry in nuclei, namely the dependence of the pseudospin splittings on the shape of the nuclear mean-field potential.Comment: 4 pages, 4 figures, to be published in Brazilian Journal of Physic

On the p-Laplace operator on Riemannian manifolds

This thesis covers different aspects of the p-Laplace operators on Riemannian manifolds. Chapter 2. Potential theoretic aspects: the Khasmkinskii condition. Chapter 3: sharp eigenvalue estimates with Ricci curvature lower bounds. Chapter 4: Critical sets of (2-)harmonic functions.Comment: PhD Thesis: Contains results obtained in collaboration with other mathematicians, see section 1.4 for details. ADDED IN THIS VERSION: correction of few typos, and added a reference brought to our attention by an anonymous referee. Details in the introduction, end of section 1.

Modeling Space-Charge Limited Currents in Organic Semiconductors: Extracting Trap Density and Mobility

We have developed and applied a mobility edge model that takes into account drift and diffusion currents to characterize the space charge limited current in organic semiconductors. The numerical solution of the drift-diffusion equation allows the utilization of asymmetric contacts to describe the built-in potential within the device. The model has been applied to extract information of the distribution of traps from experimental current-voltage measurements of a rubrene single crystal from Krellner et al. [Phys. Rev. B, 75(24), 245115] showing excellent agreement across several orders of magnitude of current. Although the two contacts are made of the same metal, an energy offset of 580 meV between them, ascribed to differences in the deposition techniques (lamination vs. evaporation) was essential to correctly interpret the shape of the current-voltage characteristics at low voltage. A band mobility 0.13 cm2/Vs for holes was estimated, which is consistent with transport along the long axis of the orthorhombic unit cell. The total density of traps deeper than 0.1 eV was 2.2\times1016 cm-3. The sensitivity analysis and error estimation in the obtained parameters shows that it is not possible to accurately resolve the shape of the trap distribution for energies deeper than 0.3 eV or shallower than 0.1 eV above the valence band edge. The total number of traps deeper than 0.3 eV however can be estimated. Contact asymmetry and the diffusion component of the current play an important role in the description of the device at low bias, and are required to obtain reliable information about the distribution of deep traps