FLOW THROUGH Research Articles

Acute toxicity of Cd in stream invertebrates in relation to pH and test design

The acute toxicity of Cd to three stream invertebrates (Baetis rhodani Pict., Leptophlebia marginata (L.) and Pisidium sp.) was tested at pH 5 and 7 simultaneously in static (ST) and flow through (FT) systems. In the static design, the animals were kept individually in small boxes containing aerated stream water. In the flow through system, the three species were kept together in circular aquaria simulating stream ecosystems with patches of gravel and recirculating aerated stream water. The nominal Cd concentrations ranged from 0 to 5 mg 1−1 during an exposure period of 120 h.

The Ex Ante Information Content of Accounting Information Systems

This study examines the effect of the particular set of accounting methods used by a firm (its information system) on the ex ante information content of its earnings announcements. The results suggest that reported income figures produced from a system consisting of inventory, depreciation, and tax credit accounting methods which are consistent in their effects on net income are more informative than when those effects are inconsistent. Informativeness of an earnings announcement is estimated by the expected increased variability in share prices at the earnings announcement date, using the option-pricing methodology introduced by Patell and Wolfson [1979; 1981]. An accounting information system can be defined by the product of managers' choices with respect to alternative methods of accounting for various items (Demski [1972]). For example, managements can choose between last-in, first-out (LIFO) and first-in, first-out (FIFO) for determining the cost of inventory; between straight-line (SL) and accelerated (ACC) to account for depreciation; and between deferral (DEF) and flowthrough (FT) to account for the investment tax credit. The collective choice from alternative methods constitutes a firm's accounting information system (e.g., LIFO-ACC-FT). Prior research has indicated that annual and interim accounting reports are informative.' There have also been attempts to assess the * Oklahoma State University. I wish to acknowledge the support of Professors T. Williams, W. Frank, R. D. Nair, J. Hickman, and W. Taylor in the completion of the dissertation on which this article is based. The comments of J. Boatsman, N. Dopuch, K. Schipper, R. Leftwich, the participants of the accounting workshop at Oklahoma State University, and anonymous referees are appreciated. 1 Beaver [1968], May [1971], and Gonedes [1974], for example.

A factor stimulating the transcription by nucleolar RNA polymerase in the nucleolus of rat liver

The flow-through(FT) fraction of DEAE-Sephadex chromatography of RNA polymerase solubilized from isolated nucleoli of rat liver specifically stimulated transcription by nucleolar RNA polymerase. The effect was observed only with native DNA used as template but not with heat-denatured DNA. The activity was trypsin-sensitive but relatively heat stable. Although the fraction contained DNase activity as revealed by the alteration of sedimentation properties of SV40 DNA, evidence is presented that the stimulatory activity is not ascribed to this DNase activity.