45 research outputs found
Hopf Map and Quantization on Sphere
Quantization of a system constrained to move on a sphere is considered by
taking a square root of the ``on sphere condition''. We arrive at the fibre
bundle structure of the Hopf map in the cases of and . This
leads to more geometrical understanding of monopole and instanton gauge
structures that emerge in the course of quantization.Comment: 9 pages, LaTeX2e, uses amsmath.st
Inequivalent Quantization in the Skyrme Model
Quantum mechanics on manifolds is not unique and in general infinite number
of inequivalent quantizations can be considered. They are specified by the
induced spin and the induced gauge structures on the manifold. The
configuration space of collective mode in the Skyrme model can be identified
with and thus the quantization is not unique. This leads to the
different predictions for the physical observables.Comment: 16 pages, LaTeX2
Further progress on application of ADAPT-VPA to Antarctic minke whales
The ADAPT-VPA assessment methodology originally developed by Butterworth et al. (1999) has been appreciably advanced by taking into account various comments made during a series of IWC-SC meetings and is applied here to abundance estimates (from both IDCR/SOWER and JARPA surveys) as well as catch at age data (both commercial and scientific) for the I and P-stocks of Antarctic minke whales. The improvements to the methodology allow account to be taken of various further aspects, primarily: 1) inter-annual differences in the distribution of the population between different management Areas, 2) a stock-recruitment relationship, 3) the effects of possible ageing-error, and 4) the effects of possible change in age-at-sexual maturity over time as indicated by analyses of readings of transition phases in ear plugs. Furthermore sensitivities to various functional forms for selectivity and natural mortality with age are explored. The general pattern shown by analysis for both stocks is of a minke whale abundance trend that increased over the middle decades of the 20th Century to peak at about 1970, and then stabilized or declined somewhat for the next three decades. The recruitment trend is similar, though with its peak slightly earlier. The annual natural mortality rate, M, is estimated to be 0.056 with a CV of 0.16 for the I-stock, and 0.069 with a CV of 0.15 for the P-stock for the “Reference case” assessments. When only the JARPA abundance estimates are used for tuning, M is estimated as 0.037 and 0.060 for the I- and P-stocks, respectively. The estimation of M is fairly robust to the various assumptions of the model. This analysis is considered preliminary, as conclusions relating to estimates of M and trends in abundance and recruitment obtained using this approach await further revisions of 1) abundance estimates obtained from IDCR and JARPA surveys, and 2) error-models for the catch-at-age data, particularly those obtained from the commercial harvests
Berry Connections and Induced Gauge Fields in Quantum Mechanics on Sphere
Quantum mechanics on sphere is studied from the viewpoint that the
Berry's connection has to appear as a topological term in the effective action.
Furthermore we show that this term is the Chern-Simons term of gauge variables
that correspond to the extra degrees of freedom of the enlarged space.Comment: 12 pages, LaTeX2
Lost equivalence of nonlinear sigma and models on noncommutative space
We show that the equivalence of nonlinear sigma and models which is
valid on the commutative space is broken on the noncommutative space. This
conclusion is arrived at through investigation of new BPS solitons that do not
exist in the commutative limit.Comment: 17 pages, LaTeX2
Application of ADAPT-VPA to Antarctic minke whales in the JARPA research area
The ADAPT-VPA assessment methodology originally developed by Butterworth et al. (1999) has been greatly improved by taking into account various comments made during a series of IWC-SC meetings and is applied here to abundance estimates (from both IDCR/SOWER and JARPA surveys) as well as catch at age data (both commercial and scientific) for the I and P-stocks of Antarctic minke whales. The improvements to the methodology allow account to be taken of various further aspects, primarily: 1) inter-annual differences in the distribution of the population between different management Areas, 2) a stock-recruitment relationship, and 3) the effects of possible ageing-error. Furthermore sensitivities to various functional forms for selectivity and natural mortality with age are explored. The general pattern shown by the results for both stocks is of a minke whale abundance trend that increased over the middle decades of the 20th Century to peak at about 1970, and then stabilized or declined somewhat for the next three decades. The recruitment trend is similar, though with its peak slightly earlier. The annual natural mortality rate, M, is estimated to be 0.056 with a CV of 0.16 for the I-stock, and 0.069 with a CV of 0.15 for the P-stock for the “Reference case” assessments. When only the JARPA abundance estimates are used for tuning, M is estimated as 0.038 and 0.060 for the I- and P-stocks, respectively. The estimation of M is fairly robust to the various assumptions of the model. The CVs of these M estimates for the “Reference case” assessments, when compared with those of typically 0.35 for the Areaspecific assessments of Butterworth et al. (1999) which were based on fewer data, indicate an improvement in the precision of these estimates due to the accumulation of data over the long-term of the JARPA surveys. The fits of the stock-recruitment model generally require a carrying capacity for minke whales that first increased and then stabilized or declined somewhat during the last century, and suggest MSYR(1+) values in the 4-6% range. The improved precision in the estimation of M may contribute in the improvement of management and assessment of this species on a stock-specific basis, since it can reduce the uncertainty concerning the value of M and can provide an improved prior distribution for MSYR. The latter in particular, in the context of providing a measure of the productivity of which the species is capable, is essential information for effective RMP implementation through reduction of the range of plausible scenarios which need to be considered in Implementation Simulation Trials.http://www.mth.uct.ac.za/maram/pub/2006/SC_D06_J14.pd
An integrated approach for the estimation of abundance through a random-effects model
Let Nay be the true abundance in the a-th survey block in the year y, and let Nˆ ay (P) and Nˆ ay (C) denote estimates of Nay obtained from passing-mode and closing-mode surveys respectively. If abundance estimates in different blocks or years include common parameters such as effective search half-width, then any two of them are correlated, and the method following takes this into account