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Growth Estimates (growth + estimate)

Distribution by Scientific Domains
Earth and Environmental Science57%

Selected Abstracts

Logistic Population Growth in the World's Largest Cities

GEOGRAPHICAL ANALYSIS, Issue 4 2006
Gordon F. Mulligan
This article demonstrates that recent population growth in the world's largest cities has conformed to the general parameters of the logistic process. Using data recently provided by the United Nations, logistic population growth for 485 million-person cities is analyzed at 5-year intervals during 1950,2010, with the UN projections for 2015 adopted as upper limits. A series of ordinary least-squares regression models of increasing complexity are estimated on the pooled data. In one class of models, the logarithms of population proportions are specified to be linear in time, which is the standard approach, but in a second class of models those proportions are specified as being quadratic. The most complex models control logistic growth estimates for (i) city-specific effects (e.g., initial population), (ii) nation-specific effects (e.g., economic development, age distribution of population), and (iii) global coordinates (for unobserved effects). Moreover, the results are segregated according to each city's membership in four different growth clubs, which was an important finding of previous research. [source]

The growth of the common two-banded seabream, Diplodus vulgaris (Teleostei, Sparidae), in Canarian waters, estimated by reading otoliths and by back-calculation

JOURNAL OF APPLIED ICHTHYOLOGY, Issue 2 2003
J. G. Pajuelo
Summary The yearly nature of increment formation in the otoliths of 1,9-year-old seabream, Diplodus vulgaris (E. Geoffrey Saint-Hilaire 1817), from the Canary Islands was validated. The marginal increment method showed that the opaque rings were formed in summer, and the translucent rings in winter. The Brody Proportional Hypothesis and the power length,radius relationship used to back-calculate the growth trajectories of D. vulgaris showed that this growth model could provide reasonable growth estimates in this species. Growth back-calculation and growth estimates obtained by direct otolith readings were similar. Data on age and size used to estimate the parameters of the von Bertalanffy growth model for D. vulagris from the Canary Islands showed that males and females had similar growth rates. [source]

Temperature and prey quality effects on growth of juvenile walleye pollock Theragra chalcogramma (Pallas): a spatially explicit bioenergetics approach

JOURNAL OF FISH BIOLOGY, Issue 3 2007
M. M. Mazur
A bioenergetics model for juvenile age-0 year walleye pollock Theragra chalcogramma was applied to a spatially distinct grid of samples in the western Gulf of Alaska to investigate the influence of temperature and prey quality on size-specific growth. Daily growth estimates for 50, 70 and 90 mm standard length (LS) walleye pollock during September 2000 were generated using the bioenergetics model with a fixed ration size. Similarities in independent estimates of prey consumption generated from the bioenergetics model and a gastric evacuation model corroborated the performance of the bioenergetics model, concordance correlation (rc) = 0·945, lower 95% CL (transformed) (L1) = 0·834, upper 95% CL (transformed) (L2) = 0·982, P < 0·001. A mean squared error analysis (MSE) was also used to partition the sources of error between both model estimates of consumption into a mean component (MC), slope component (SC), and random component (RC). Differences between estimates of daily consumption were largely due to differences in the means of estimates (MC= 0·45) and random sources (RC= 0·49) of error, and not differences in slopes (SC= 0·06). Similarly, daily growth estimates of 0·031,0·167 g day,1 generated from the bioenergetics model was within the range of growth estimates of 0·026,0·190 g day,1 obtained from otolith analysis of juvenile walleye pollock. Temperature and prey quality alone accounted for 66% of the observed variation between bioenergetics and otolith growth estimates across all sizes of juvenile walleye pollock. These results suggest that the bioenergetics model for juvenile walleye pollock is a useful tool for evaluating the influence of spatially variable habitat conditions on the growth potential of juvenile walleye pollock. [source]

Polynomial stability of operator semigroups

MATHEMATISCHE NACHRICHTEN, Issue 13-14 2006
András Bátkai
Abstract We investigate polynomial decay of classical solutions of linear evolution equations. For bounded strongly continuous semigroups on a Banach space this property is closely related to polynomial growth estimates of the resolvent of the generator. For systems of commuting normal operators polynomial decay is characterized in terms of the location of the generator spectrum. The results are applied to systems of coupled wave-type equations. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

SOURCES OF PRODUCTIVITY GROWTH IN AUSTRALIAN TEXTILE AND CLOTHING FIRMS,

AUSTRALIAN ECONOMIC PAPERS, Issue 3 2007
I.K.M. MOKHTARUL WADUD
This paper estimates the sources of productivity growth in Australian textile and clothing firms based on the Business Longitudinal Survey (BLS) from 1995 to 1998. Productivity growth estimates have been obtained for each sub-category of textile and clothing firms. Sources of growth in multifactor productivity (MFP) are examined with growth in technical efficiency and scale effects based on estimates of stochastic frontier production functions. Separate estimates of output growth have been compared with the productivity growth estimates for each of the product categories. MFP improved in all clothing firms and declined in textile firms over 1997,1998 by four-digit level of Australia New Zealand Standard Industrial classification Scheme (ANZSIC). MFP declined in most major categories of both textile and clothing firms in 1995,1997. Changes in technical efficiency mostly dominated scale effects in the overall direction of MFPG in both textile and clothing firms. The findings of the study provide evidence for policies for improving the firms' operative performance in the ongoing liberalised regime. [source]