Strategic Regulators and the Choice of Rulemaking Procedures: The Selection of Formal vs. Informal Rules in Regulating Hazardous Waste

The selection of decisionmaking procedures by regulatory agencies is examined, using the EPA and its implementation of the Resource Conservation and Recovery Act as a source of data. The role that congressional selection of agency procedures plays in the efforts of Congress to control agency policy is refined

Comparing the Applicability of Weight-Length Relationships, the Relative Condition Index and Morphometric Criteria to Assess Larval Condition: A Test Case with Striped Bass

We compared the applicability of using a weight-length relationship, the relative condition index (Kn) and morphometric criteria to provide insight on the nutritional condition and recruitment potential of larvae of the striped bass Morone saxatilis collected in the Potomac River, MD in 1980-1982 and 1986. Morphometric data indicate that relatively high numbers of larvae In poor condition were present In samples taken prior to mid-May In all years except 1986, but especially In 1980 and 1981. Results of ANCOVA on a subset of data from the first 2 weeks of May In each of the 4 years Indicated significant differences in weight-length regression equations. Larvae In the 1980 and 1981 samples were in poorer condition than in 1982 and 1986, based on regressions coefficients. Estimates of relative condition (Kn) were high in all years except 1986. The morphometric criteria and the regression parameter estimates concurred with an Index of striped bass year class strength, but only after a careful consideration of the assumptions of those condition indices, requiring a reduction in sample size that excluded larger larvae (\u3e 12 mm, morphometric criteria) or averaging data over several larval cohorts (regression parameters)

The Effect of Item Distance on Organization in the Free Recall of Words

The purpose of the present study was to investigate the effect of item distance, which is defined as the absolute number of words separating a single item from the other items of the category, upon clustering of the removed items. By studying clustering, psychologists hope to gain knowledge of the effect of organization on memory

Game bird investigations : quail and chukar partridges

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Cap mesenchyme cell swarming during kidney development is influenced by attraction, repulsion, and adhesion to the ureteric tip

Morphogenesis of the mammalian kidney requires reciprocal interactions between two cellular domains at the periphery of the developing organ: the tips of the epithelial ureteric tree and adjacent regions of cap mesenchyme. While the presence of the cap mesenchyme is essential for ureteric branching, how it is specifically maintained at the tips is unclear. Using ex vivo timelapse imaging we show that cells of the cap mesenchyme are highly motile. Individual cap mesenchyme cells move within and between cap domains. They also attach and detach from the ureteric tip across time. Timelapse tracks collected for >800 cells showed evidence that this movement was largely stochastic, with cell autonomous migration influenced by opposing attractive, repulsive and cell adhesion cues. The resulting swarming behaviour maintains a distinct cap mesenchyme domain while facilitating dynamic remodelling in response to underlying changes in the tip