Stock Growth Rate Research Articles

素材ストックの成長率が低減していく場合の素材リサイクルシステムの解析と鉄鋼への適用

素材ストックの成長率が低減していく場合の素材リサイクルシステムの解析と鉄鋼への適用

Bioenergetic analysis of the effects of temperature and prey availability on growth and condition of northern cod (Gadus morhua)

Atlantic cod (Gadus morhua) stocks of the Northwest Atlantic have experienced steady decreases in growth rate since 1989 and in physiological condition since 1988. The declines have been attributed to various factors, including size- selective fishing pressure, anomalously low temperature fields, and a decline in available prey. The precise balance of these factors is unknown. We applied simple correlation models to determine that bottom water temperature and capelin ( Mallotus villosus) biomass together explain 52% of the interannual variance in mean condition of 2J3K cod and 23% of the interannual variance in 2J3KL mean cod growth rates. Bioenergetic models can potentially improve our understanding of the mechanisms behind these relationships because they allocate energy as a function of environmental parameters such as water temperature and prey consumption. We developed a bioenergetic model for Atlantic cod to determine whether temperature could explain the observed decreases in growth rate of northern cod stocks. Our results suggest that the low growth rates of 2J3K northern cod observed in recent years are not due to physiological temperature limitation, while the growth rates of cod inhabiting cooler waters on the northern Grand Banks (3L) may, at least in certain years, be temperature limited.

France and the CFA: Price and Money Supply Growth Determination: 1969–88

This paper examines the relationship between the rates of inflation and money stock growth in the CFA zone and France between 1969 and 1988. Theory holds, all other things being equal, that these inflation and money stock growth rates should be indistinguishable between France and the various CFA countries. Regression analysis confirms that the inflation rate in the CFA countries examined generally follows the predicted pattern while money supply data produces more mixed results. From this, it follows that there are no indications of an overvalued exchange between the CFA and France over the period covered. Copyright 1995 by Oxford University Press.

What's the Long-Term Expected Return to Your Portfolio?

Many investors and investment consultants use mean-variance optimizers to select efficient portfolios. Mean-variance optimization is inherently a single-period technique. Most investors use it in a multiyear context by assuming annual rebalancing and independence and stationarity of returns. These assumptions are often reasonable, and they enable investors to estimate a portfolio's future growth rate, or long-term expected return. Investors such as definedbenefit plan sponsors and foundations have a keen interest in the long-term expected returns to their portfolios. Sponsor contributions and foundation budgets are often tied directly to this estimate of the future growth rate of assets. This focus on a future portfolio growth rate appears to lead many practitioners mistakenly to use past growth rates to asset classes as inputs to their mean-variance optimizers. The consequence of this error is an estimated longterm expected return to the portfolio that is likely to be at least 50 basis points lower than the correct estimate. Correct estimation of a portfolio's future multiperiod growth rate is a two-step procedure. First, determine the single-period characteristics of portfolio returns. Then, estimate the multiperiod characteristics of those singleperiod returns. A simple example illustrates this point. From Ibbotson Associates' Stocks, Bonds, Bills, and Inflation 1994 Yearbook, the compound annual growth rates to largecompany stocks and long-term corporate bonds from December 31, 1925, through December 31, 1993, were 10.3 percent and 5.6 percent, respectively. These numbers could be used as estimates of future long-term expected returns to stocks and bonds. To estimate the future growth rate to a portfolio of stocks and bonds, rebalanced annually to 50/50, one might be tempted simply to take the arithmetic average of the stock and bond growth rates. This calculation is quick and easy, and it yields an estimated future portfolio growth rate of 7.9 percent. One might think 7.9 percent is a reasonable estimate, but it is not. Using the two-step procedure outlined in the preceding paragraph, first calculate all 68 annual portfolio returns to stocks and bonds. In the second step, calculate the annual growth rate from these 68 annual portfolio returns. That growth rate is 8.4 percent, 50 basis points higher than the quick and easy estimate of 7.9 percent! The stock/bond version of the erroneous calculation is given in Equation 1. Equation 1 is appropriate for calculating the singleperiod, say annual, expected return to a portfolio, because it holds for actual annual rates of return. Skipping Step 1 by using growth rates in Equation 1 is a mistake, however, because a portfolio growth rate is not a linear combination of the growth rates of the assets in the portfolio. An annualized growth rate calculated from a series of annual returns will be lower than the arithmetic average of the returns because of volatility. A simple approximation of this relationship is given in Equation 4. Use of Equation 1 with long-term expected returns ignores the reduction in volatility coming from diversification between the two assets and yields a long-term expected return that is too low. The more diversified the portfolio, the larger the error. To convince yourself about this, just follow through the details of the stock and bond example below. This is the same example as above, except that Equation 4 is used for Step 2 rather than a calculation of all 68 annual portfolio returns.

Poultry production in Ethiopia

Poultry production systems are outlined under the social and physical environmental conditions of Ethiopia. The results of research on the performance of local domestic fowl and on the performance and adaptability of imported stocks and resulting crosses with native fowl are also assessed. Farmyard/backyard type production, in which native fowl scavenge for most of their food, predominates and is widespread in the rural community. Both state and privately owned commercial farms using imported stocks are beginning to develop around urban centres. The egg production and growth rates of native stocks are low. Under prevailing management conditions it has been found that crosses between native stock and imported White Leghorns, incorporating about 60% White Leghorn blood, perform better than either parent types.

‘The spirit of capitalism’ and long-run growth

In this paper, we will show that the capitalist-spirit approach to economic growth has been developed by Adam Smith, Karl Marx, Max Weber and John Maynard Keynes and many others. It can be demonstrated that countries with different degree of the capitalist spirit will have different per capita consumption, per capita capital stock and different endogenous growth rates in the long run. This capitalist spirit model is also widely supported by many empirical and historical studies on cultural attributes and economic development.

Reply to González-Calvet and Sánchez-Chóoliz

My 1989 paper, on which the comments of Gonzalez-Calvet and Sdnchez-Ch6liz focus, had a fairly simple goal. It attempted to show that partially endogenous credit and effective demand might combine to produce self-sustained growth cycles. Using a dynamical model of interest and capital stock growth rates, sufficient conditions for self-sustained cycles were derived. Based on these conditions, it was argued that ceteris paribus stronger firn response to cash flow could, in some cases, make cycles more likely. It also was pointed out that increased endogeneity in the supply of credit would make it more likely that the sufficient conditions would be met. As the authors of these comments have recognized, that paper contained some algebra errors. The expression for Tr(J), the trace of the Jacobian of the model, was incorrectly written in the text. The expression for r2, the value of the r = 0 isocline when r = 0, contains an error. Also the labeling in the phase diagram in figure 2 is at variance with the appendix, where the proof of the existence of cycles is stated.' None of these mistakes should have been made. I apologize for any inconvenience they may have caused readers.

On the stability of the stock‐harvesting system controlled by a feedback management procedure

SummaryStability of the stock‐harvesting system regulated by a feedback control procedure of catch quota is examined. In the procedure considered, catch quota is changed proportionally to the difference between current and the target stock level (with a proportionality constant h) and to the annual stock growth rate (with a proportionality constant g). Condition for the local stability of the target equilibrium is obtained as a function of the stock‐recruitment relation, survival probability of adults, target stock level, time lag before implementation of regulation, age of sexual maturity of the stock, and proportionality constants g and h. It is shown that, (1) the procedure has the stabilizing effect; it can stabilize the target stock level that is unstable under constant harvest, (2) lower target stock level favors larger g and smaller h, when the target is set around MSYL (the stock level that gives MSY), (3) the degree of stability, measured by the time required to recover the target stock level, is an increasing function of the target stock level, (4) stability and sustainable yield are in trade‐off, (5) time delay caused by the time needed before sexual maturity does not affect the stability significantly, but the effect of the time lag before implementation of regulation is significant. Comparison between harvest‐control and effort‐control procedures is also made, and the advantage of the latter in terms of stability is shown.

NITROGEN NUTRITION OF CITRUS NURSERY STOCK IN PINE BARK SUBSTRATES.

Pine bark is utilized as a substrate in citrus nurseries in South Africa. The Nitrogen (N) content of pine bark is inherently low, and due to the volubility of N, must be supplied on a continual basis to ensure optimum growth rates of young citrus nursery stock. Three citrus rootstock (rough lemon, carrizo citrange and cleopatra mandarin) showed no difference in stem diameter or total dry mass (TDM) when supplied N at concentrations between 25 and 200 mg ·l-1 N in the nutrient solution over a 12 month growing period. Free leaf arginine increased when N was supplied at 400 mg·l-1 N. The form of N affected the growth of rough lemon. High NH4-N:NO3-N (75:25) ratios decreased TDM when Sulfur (S) was absent from the nutrient solution, but not if S was present. Free arginine increased in leaves at high NH4-N (No S) ratios, but not at high NH4-N (S supplied) ratios. Free leaf arginine was correlated with free leaf ammonia. These results have important implications for reducing the concentration of N in nutrient solutions used in citrus nurseries and may indicate that higher NH4-N ratios can be used when adequate S is also supplied.

Field experience with new pasture cultivars in Canterbury

Over the last 10 years Canterbury farmers have started to diversify their pasture base in order to optimise their stock production. While ryegrass is still the base grass of our pastoral system, it is unsuited to many sites where pasture must generate high stock growth rates despite seasonally low rainfall, high soil temperatures and pasture pest challenge. On such sites, pastures based on cocksfoot, (Dactylis glomerata L.), phalaris (Phalaris aquatica L . ) and tall fescue (Festuca arundinacea Schreb.) or prairie grass (Bromus willdenowii Kunth, cv. 'Grasslands Matua') or lucerne (Medicago sativa) or chicory (Cichorium intybus L.) have lifted net farming returns. Keywords ryegrass, endophyte, tall fescue, phalaris, cocksfoot, prairie grass, chicory, pasture pests, rainfall, stock production, pasture persistence

Australian private-vehicle fleet changes on register and on road, 1971–1982

Despite stagnation in new-vehicle sales from the mid 1970s, both the size and total usage made of the Australian stock of cars and station wagons continued to grow unabated into the early 1980s. Such apparently contradictory trends were an international phenomena, as were increased sourcing of vehicles from Japanese manufacturers, and the experience of less than favourable economic and demographic conditions. This paper looks at the factors behind the movements noted, and attempts to assess to what extent the “downsizing” phenomena observed overseas was encountered in Australia. Increasing vehicle life expectancy and an initially favourable age structure were found to account for contradictory growth rates in new registrations and the vehicle stock, while increased lifetime utilisation of light/medium vehicles accounted for much of the increase observed in total distance travelled. Only a weak downsizing trend was detected commencing circa 1979, its weakness reflecting an unexpected trend away from light vehicles. Projections indicate that if levels of, and size patterns associated with, new-vehicle registrations persist, downsizing trends will continue to be weak, and overall stock growth rates are likely to slow, although stagnation is unlikely by 1990.

Uncertainty in the Theory of Renewable Resource Markets

The natural growth rate of most renewable resource stocks is in part stochastic. This paper examines the implications of such ecological uncertainty for competitive equilibrium in a market with property rights. We show that stochastic fluctuations add a risk premium to the rate of return required to keep a unit of stock in situ, and we examine the effects of fluctuations on resource rent. Examples are used to show that extraction can increase, decrease, or be left unchanged as the variance of the fluctuations increases, depending on the extent of market self-correction. Regulatory implications are also discussed. Renewable resource economics has traditionally been concerned with the study of dynamically optimal harvesting policies given a deterministic function for the natural growth of the resource stock. Issues have included the existence and characteristics of steady-state equilibria for the optimally managed resource, the need for and design of regulatory policies to prevent over-exploitation, and conditions under which (as a social optimum or otherwise) the resource will be exploited to extinction.1 Much of this work has been based on the assumption of a fixed and exogenous price for the harvested resource (typically resulting in bang-bang solutions for the harvesting policy). However some recent papers make price endogenous, and thereby describe how the extraction rate, and the rate of return and asset value of the resource behave in a competitive market with property rights.2

Growth of Baltic salmon Salmo salar in the sea

Growth of Baltic salmon Salmo salar in the sea

La politique yougoslave de développement régional, 1952-1971

Yugoslav Regional Development Policy, 1952-1971. This paper analyzes the regional economic policy carried out by the Yugoslav government during the first twenty years of the workers' self-management period as it affected industrial development. The first major section reports a measurement of industrial growth in the republics and autonomous provinces of Yugoslavia during the period in question using a special sample index developed for this purpose. Overall and per capita growth rates derived from the index and population data in the areas indicate that the policy generally failed to meet industrial growth objectives. A program transferring investment funds from more developed to less developed areas was a major component of the regional policy. The volume of investment fund transfers and interregional differences in capital stock growth rates resulting from it are investigated next. The size of the investment fund transfers and their impact on national industrial growth are taken up in the paper's next section. Only the roughest estimates of the size of the transfers are possible with available data. Certain inconsistencies of the regional policy are taken up in the final section of the paper. It notes that Yugoslav economists generally agree that the program failed during the period under consideration. Many reasons given by them for the failure are discussed.

Compensatory Growth of Selected and Nonselected Broilers Following Early Protein Restriction

The influence of early protein restriction on the growth rate of broiler stocks with different genetic potential was investigated in three trials. The protein restriction used was a dietary treatment consisting of a 16% protein diet from 0 to 2 weeks of age followed by a 22% protein diet from 2 to 8 weeks of age. This treatment was compared to dietary treatments consisting of 16% and 22% protein from 0 to 8 weeks of age.Commercial broiler chicks (selected) had feed intake and body weights approximately twice that of randombred (nonselected) chicks. There was little evidence of compensatory growth following low protein restriction from 0 to 2 weeks of age. Immediately following the change from the 16% protein diet to the 22% protein diet, feed conversions of the restricted birds were superior to feed conversions of birds fed the 22% protein diet from 0 to 8 weeks. Although the magnitude of the difference was small, it continued for a 3-week period and was consistent across trials.