The Choice of Inflation Targeting

This paper assesses empirically the contribution of key macroeconomic and institutional variables in shaping the likelihood of choosing the Inflation Targeting (IT) regime in a sample that comprises countries working under such a regime and covers the period 1975-2005. I find inflation rate, financial development, GDP per capita and trade openness relevant for driving the choice of IT by estimating a discrete choice panel data model. Also, my results suggest that the initial conditions at the moment of IT adoption do matter because countries have different exposure to the likelihood of choosing IT as a result of their specific macroeconomic and institutional fundamentals and unobservable idiosyncratic factors.

Aspects of selection in an interbred flock based on Perendales crossed with Merino X Romney ewes : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Animal Science at Massey University

Genetic, phenotypic and environmental parameters were estimated from hogget traits recorded on 237 Perendale x (Merino x Romney) ewe hoggets between 1977 and 1984. Non-genetic effects on weaning weight (WW) for 634 ewe and ram lambs were analysed. A selection objective and criteria was defined and appraised for the flock. The traits examined were hogget liveweight (HLW), greasy fleece weight (GFW), clean fleece weight (CFW), quality number (QN), character grade (CHG), handle grade (HG), cotting grade (CG), soundness grade (SG), greasy colour grade (GCG), scoured colour grade (SCG), staple length (SL), total crimp number (TCN), clean scoured yield (Y), mean fibre diameter (MFD) and crimps per centimetre (CPC). The least squares method of fitting constants was used to estimate the major environmental factors influencing the traits studied. Heritabilities (h2) were obtained by the daughter-dam regression (DDR) and daughter-dam correlation (DDC) methods. The genetic (rG), phenotypic (rP) and environmental (rE) correlations were calculated by the daughter-dam method. The estimates of environmental effects agree in most cases with the published estimates. Between year differences were important sources of variation and had a highly significant effect on all traits except SCG. Rearing rank effect was found to be the most important source of variation for WW and HLW. Age of dam and sex had a highly significant effect on WW. Neither rearing rank nor age of dam exerted any significant influence on wool traits. The estimates of heritability calculated by daughter-dam regression method were: HLW (0.16), GFW (0.17), CFW (0.24), QN (0.42), CHG (0.38), SG (0.02), GCG (0.38), SCG (0.09), SL (0.12), TCN (0.08), Y (0.41) and MFD (0.29). Genetic and phenotypic correlations calculated among some hogget traits were respectively: HLW x GFW (0.67 and 0.66); HLW x CFW (0.62 and 0.56); HLW x SL (0.79 and 0.44); HLW x MFD (-0.45 and 0.24); GFW x CFW (0.87 and 0.94); GFW x SL (0.37 and 0.60); GFW x MFD (-0.98 and 0.38); CFW x GCG (0.52 and 0.02); QN x MFD (-0.79 and -0.30); SG x MFD (0.73 and -0.21); GCG x SCG (0.87 and 0.38); GCG x Y (0.96 and 0.04) and SCG x Y (0.77 and 0.00). Lifetime economic weights derived using the marginal profit method were calculated to define a selection objective for the flock studied. The traits included in the objective were number of lambs weaned (NLW (dam)), WW, CFW, MFD and SCG. Besides the traits in the objective, HLW, GFW, QN and GCG were included as selection criteria. The appropriate selection indices for ram hoggets (I1), ewe hoggets (I2) and lambs (I3 ) were respectively: I1 =4.66 NLW (dam) + 0.62 HLW + 0.10 WW + 3.91 GFW - 1.70 MFD + 0.50 GCG. I2 =4.79 NLW (dam) + 0.61 HLW + 0.04 WW + 1.99 GFW + 0.23 QN + 1.60 GCG. I3 = 4.87 NLW (dam) + 0.48 WW

Bulk viscosity, interaction and the viability of phantom solutions

We study the dynamics of a bulk viscosity model in the Eckart approach for a spatially flat Friedmann-Robertson-Walker (FRW) universe. We have included radiation and dark energy, assumed as perfect fluids, and dark matter treated as an imperfect fluid having bulk viscosity. We also introduce an interaction term between the dark matter and dark energy components. Considering that the bulk viscosity is proportional to the dark matter energy density and imposing a complete cosmological dynamics, we find bounds on the bulk viscosity in order to reproduce a matter-dominated era (MDE). This constraint is independent of the interaction term. Some late time phantom solutions are mathematically possible. However, the constraint imposed by a MDE restricts the interaction parameter, in the phantom solutions, to a region consistent with a null value, eliminating the possibility of late time stable solutions with $w<-1$. From the different cases that we study, the only possible scenario, with bulk viscosity and interaction term, belongs to the quintessence region. In this latter case, we find bounds on the interaction parameter compatible with latest observational data.Comment: 8 pages, 5 figure

Quintom phase-space: beyond the exponential potential

We investigate the phase-space structure of the quintom dark energy paradigm in the framework of spatially flat and homogeneous universe. Considering arbitrary decoupled potentials, we find certain general conditions under which the phantom dominated solution is late time attractor, generalizing previous results found for the case of exponential potential. Center Manifold Theory is employed to obtain sufficient conditions for the instability of de Sitter solution either with phantom or quintessence potential dominance.Comment: 10 pages, 5 figures. References and a new section added. Minor typos corrected. The current institution of one of the authors has been update