An isoclinal approach to the comparative statics of biological communities

1986 ◽  
Vol 48 (1) ◽  
pp. 59-75 ◽  
Author(s):  
Grant G. Thompson ◽  
W. Michael Booty ◽  
William J. Liss ◽  
Charles E. Warren
1986 ◽  
Vol 48 (1) ◽  
pp. 59-75
Author(s):  
G THOMPSON ◽  
W BOOTY ◽  
W LISS ◽  
C WARREN

Author(s):  
Jamal Othman ◽  
Yaghoob Jafari

Malaysia is contemplating removal of most of her subsidy support measures including subsidies on cooking oil which is largely palm oil based. This paper aims to examine the effects of cooking oil subsidy removals on the competitiveness of the oil palm subsector and related markets. This is done by developing and applying a comparative static, multi-commodity, partial equilibrium model with multi-stages of production function for the Malaysian perennial crops subsector which explicitly links different stages of production, primary and intermediate input markets, trade, and policy linkages. Results partly suggest that export of cooking oil will increase by 0.2 per cent due to a 10 per cent cooking oil subsidy reduction, while domestic output of cooking oil may eventually see a net decline of 1.97 per cent. The results clearly point out that the effect of reducing cooking oil subsidies is relatively small at the upstream levels and therefore it only induces minute effects on factor markets. Consequently, the market for other agricultural crops is projected to change very marginally.   Keywords: Multicomodity, comparative statics, partial equilibrium model, output supply-factor markets linkages, effects of cooking oil subsidy removals.


1991 ◽  
Vol 8 (1) ◽  
pp. 109-127
Author(s):  
Zaidi Sattar

The present paper is a contribution to the building blocks of an investmentmodel within the framework of an integrated macroeconomic model of anIslamic economy. Investment behavior in the model is guided by an Islamicethicalvalue system and profit-sharing financial contracts. The typical firm’sinvestment decision is believed to emerge from a dynamic inter-temporalmaximization exercise within an infinite time horizon. The method of Calculusof Variations is applied to arrive at the optimal investment and employmentcriteria for the firm. The result is then incorporated into a macroeconomicmodel to study the behavior of key endogenous variables like national incomeand the rate of profit-share. Comparative statics exercised within a generalequilibrium framework reveal the potency of monetary policy but the neutralityof fiscal policy with respect to output and employment.IntroductionThe past decade has witnessed a tremendous outpouring of interest aswell as effort in the formalization of economic models based on profit-sharingfinancial arrangements as an Islamic alternative to the conventional interestbasedeconomic system. Several macroeconomic models for interest-freeeconomies have been proposed (Anwar 1987; Habibi 1987; Metwally 1981& 1983). The rigor of an integrated approach to such macroeconomic modelhgdepends on the rigor of the component models, namely, the consumption,investment, monetary, and fiscal relationships. Economists have writtenextensively on different aspects of consumer behavior in Islamic societies.Kahf (1978) and Khan (1984), among others, have contributed to the conceptualand analytical formulation of the consumption function under ...


Author(s):  
David A. Malueg ◽  
Andrew James Yates
Keyword(s):  

2000 ◽  
Vol 31 (4-5) ◽  
pp. 411-422 ◽  
Author(s):  
Gísli Már Gíslason ◽  
Jón S. Ólafsson ◽  
Hákon Adalsteinsson

The characteristics of stream and river ecosystems in arctic and alpine areas are determined mainly by the relative contribution of glacial meltwater, snowmelt, rainfall and groundwater. Each source generates a particular seasonal hydrological signature, affecting physical and chemical properties, and hence biological communities. The relative contribution of each source is sensitive to climate change. The study was concentrated on the glacial River W-Jökulsá and some non-glacial rivers in the central highlands of Iceland. The water in the glacial river was entirely glacial meltwater at the glacier margin, but the glacial contribution was about 20% 40 km downstream. However, its tributaries and non-glacial reference rivers were mainly springfed. The invertebrate fauna was confined to Chironomidae of the genus Diamesa close to the glacier, but other taxa (species and groups of species) occupied the river further downstream, where their diversity was close to that found in the reference rivers.


Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 481
Author(s):  
Sarah A. Morley ◽  
Linda D. Rhodes ◽  
Anne E. Baxter ◽  
Giles W. Goetz ◽  
Abigail H. Wells ◽  
...  

All cities face complex challenges managing urban stormwater while also protecting urban water bodies. Green stormwater infrastructure and process-based restoration offer alternative strategies that prioritize watershed connectivity. We report on a new urban floodplain restoration technique being tested in the City of Seattle, USA: an engineered hyporheic zone. The hyporheic zone has long been an overlooked component in floodplain restoration. Yet this subsurface area offers enormous potential for stormwater amelioration and is a critical component of healthy streams. From 2014 to 2017, we measured hyporheic temperature, nutrients, and microbial and invertebrate communities at three paired stream reaches with and without hyporheic restoration. At two of the three pairs, water temperature was significantly lower at the restored reach, while dissolved organic carbon and microbial metabolism were higher. Hyporheic invertebrate density and taxa richness were significantly higher across all three restored reaches. These are some of the first quantified responses of hyporheic biological communities to restoration. Our results complement earlier reports of enhanced hydrologic and chemical functioning of the engineered hyporheic zone. Together, this research demonstrates that incorporation of hyporheic design elements in floodplain restoration can enhance temperature moderation, habitat diversity, contaminant filtration, and the biological health of urban streams.


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