“Tax Simplification”—Grave Threat to the Charitable Contribution Deduction: The Problem and a Proposed Solution

The present National Administration has continued to support proposed legislative changes aimed at substantially reducing the number of income tax returns in which deductions are itemized. The author contends that these tax simplification proposals are incompatible with the preservation of the charitable contribution deduction and would undermine the position of voluntary charitable organizations by reducing the incentives for giving. He proposes a solution to this dilemma by promoting the charitable contribution deduction, with certain limitations, to the position of a deduction from gross income, rather than a deduction from adjusted gross income

Sea-level response to ice sheet evolution: An ocean perspective

The ocean's influence upon and response to Antarctic ice sheet changes is considered in relation to sea level rise over recent and future decades. Assuming present day ice fronts are in approximate equilibrium, a preliminary budget for the ice sheet is estimated from accumulation vs. iceberg calving and the basal melting that occurs beneath floating ice shelves. Iceberg calving is derived from the volume of large bergs identified and tracked by the Navy/NOAA Joint Ice Center and from shipboard observations. Basal melting exceeds 600 cu km/yr and is concentrated near the ice fronts and ice shelf grounding lines. An apparent negative mass balance for the Antarctic ice sheet may result from an anomalous calving rate during the past decade, but there are large uncertainties associated with all components of the ice budget. The results from general circulation models are noted in the context of projected precipitation increases and ocean temperature changes on and near the continent. An ocean research program that could help refine budget estimates is consistent with goals of the West Antarctic Ice Sheet Initiative

Gaseous diffusion in glassy polymers

A model for gaseous diffusion in glassy polymers is developed with a view to accounting for the observations made in dual sorption and certain other phenomena in polymers below their glass transition temperature. In this paper a preliminary study of the effects of both the immobilizing mechanism and the generalized diffusion mechanism on travelling waves and the diffusive wavefronts is made

Lime Needs and Trends in Arkansas

Consumption of agricultural lime in Arkansas declined significantly during the past seven years. During each of the past four years, lime consumption was lower than any time since 1960. The quantity of lime needed for optimum crop production on Arkansas\u27 soils is estimated to be 2,678,700 metric tons (MT) (3,000,000 tons), based on University of Arkansas soil testing summaries. Since 1980, less than 285,728 MT(320,000 tons) of lime have been used each year. It is the natural tendency for most soils in Arkansas to become more acidic with time. Periodic addition of agricultural limestone, however, can neutralize soil acidity and help to maintain soil productivity. Nitrogen fertilizers, applied for the production of most agricultural crops, may also contribute to the acidification of soils. The annual consumption of acid-forming nitrogen fertilizers in Arkansas increased from approximately 223,225 MT(250,000 tons) during fiscal year 1974-75 to about 392,876 MT(440,000 tons) by fiscal year 1983-84. At least 2.5 times more lime was needed than was used, just to neutralize the residual acidity from acid-forming nitrogen fertilizers alone, during the same period. Shifts in crop hectareages did not account for the magnitude of decline observed in lime consumption. If lime consumption does not increase in the future, and if acid-forming nitrogen fertilizer consumption follows the current increasing trend, soil acidity will cause a decline in the yields of acid-sensitive crops

Age Estimation using Phalangeal Skeletochronology in Northern Crawfish Frogs, Lithobates areolatus circulosus (Amphibia: Anura: Ranidae), from Arkansas

As an obligate crayfish burrow dweller, crawfish frogs have historically occupied a relatively narrow ecological niche throughout their distribution in the tall grass prairies and grasslands of the central and south-central United States. In Arkansas, the Northern Crawfish Frog, Lithobates areolatus circulosus, occurs in only 19 of its 75 counties. Because of their secretive nature, late winter-early spring breeding season, and current protected status by the Arkansas Game and Fish Commission, this species remains a rarity in most museum collections in the state. Moreover, only anecdotal information exits regarding any aspect of their natural history in Arkansas. In the present study, we chose to conduct a phalangeal skeletochronological investigation using museum specimens (n = 9) deposited in the herpetological collection housed in the Arkansas Center for Biodiversity Collections located at Arkansas State University. Our results were mostly similar to the age-body length distributions from southern Illinois. Our oldest males exhibited 4 lines of arrested growth (LAGs), and this estimated age matched well with the body sizes of 4-year-old males found in Illinois. Two of our 3-year-old males had slightly larger body sizes compared to the Illinois sample. Our oldest female was 5 years old. Her body size was comparable to values found for 5-year-old females in Illinois. Also, 5 years was the maximum age recorded for this species in our study as well as for the frog in Illinois. Nine years has been reported as the maximum lifespan for this species

Supply Function Equilibria with Capacity Constraints and Pivotal Suppliers

The concept of a supply function equilibrium (SFE) has been widely used to model generators’ bidding behavior and market power issues in wholesale electricity markets. Observers of electricity markets have noted how generation capacity constraints may contribute to market power of generation firms. If a generation firm’s rivals are capacity constrained then the firm may be pivotal; that is, the firm could substantially raise the market price by unilaterally withholding output. However the SFE literature has not properly analyzed the impact of capacity constraints and pivotal firms on equilibrium predictions. We characterize the set of symmetric supply function equilibria for uniform price auctions when firms are capacity constrained and show that this set is increasing as capacity per firm rises. We provide conditions under which asymmetric equilibria exist and characterize these equilibria. In addition, we compare results for uniform price auctions to those for discriminatory auctions, and we compare our SFE predictions to equilibrium predictions of models in which bidders are constrained to bid on discrete units of output.supply function equilibrium, pivotal firm, wholesale electricity market

Inventories, Rational Expectations, and the Business Cycle

The simplest macroeconomic models in which markets clear instantaneously, and expectations are rational preclude the existence of "business cycles," that is, of serially correlated deviations of output from trend. This paper studies one of several mechanisms that can be used to make these so-called "new-classical" models produce business cycles; the mechanism is the gradual adjustment of inventory stocks. Two microeconomic models of inventory holdings are formulated. Both imply, first, that current output should be a decreasing function of the stock of inventories and, second, that inventories, once perturbed from equilibrium levels, should adjust only gradually. These two features are then embedded into an otherwise standard macroeconomic model in which markets clear instantaneously and expectations are rational. Two principal conclusions are reached. First, disturbances such as unanticipated changes in money will set in motion serially correlated deviations of output from trend. Second, if desired inventories are sensitive to the real interest rate, then even fully anticipated changes in money can affect real variables.