"Brother" and "Uncle": An Analysis of Rules, Structural Contradictions, and Meaning in Vietnamese Kinship

This paper analyzes the meanings of Vietnamese kinship terms on the basis of the rules that regulate their referential and nonreferential uses. These rules are not completely consistent with one another. They constitute contradictory models of and for sociocultural reality at a certain level. The structural contradictions among these models render "fuzzy" even the definitions of the prototypical uses of Vietnamese kin terms. The coexistence of alternative models makes the use of a linguistic form both a goal-directed action and the representation of an order.     

A behavioral bioassay employing Daphnia for detection of sublethal effects: Response to polarized light

The swimming response of Daphnia pulicaria to polarized white light was examined. This response was employed as a behavioral bioassay to investigate the effects of sodium bromide (NaBr) on Daphnids physiology. The control response to linearly polarized white light involved an orientation at 90° to the e‐vector. With the addition of NaBr the response became more random. An EC₅₀ (concentration which eliminates the response in 50% of the test individuals) of 1.31 x 10^‐1 M NaBr was calculated using the statistic von Mises K. A possible mechanism to account for the toxicity of this mild sedative is the blocking by the bromide ion of chloride channels involved in transmitting nerve impulses.     

Zooplankters as indicators of ecosystem health: past findings and future directions

Both acute (ingestion, respiration) and chronic bioassays (reproduction, survival) have been used to identify sources of pollutants. A mass-balance analysis suggests that acute tests be paired, using important indicator species asDaphnia, Ceriodaphnia and potentially others, to estimate the impact of contaminants upon the zooplankton community. Eventually groups of community bioassays may be combined to approximate an ecosystem bioassay. Hormesis or the stimulation of a physiological process by a compound which is toxic at high concentrations is characteristic of several bioassays; in this paper the ecotoxicology community is challenged to keep detailed records of the species, toxic compound, and physiological response involving hormesis in order to understand it; and ultimately to use it to simplify interpretation of bioassays. Life history characteristics of the cladoceran zooplankton, including early reproduction, high net reproductive rates, and the potential for many parthenogenetic generations with constant genotypes and low mutation rates make good choices for environmental bioassays. In contrast, high mutation rates of rotifers make them questionable choices. Five innovations, one or more of which may improve our ability to detect and identify pollutants, are suggested for ecotoxicologists using zooplankton. These include (a) the use of strains of known genotype; (b) determination of the genetic adaptation of clones to common toxins; (c) the use of common behaviors, including responses to light in detection of non-lethal chemicals at ambient levels; (d) record keeping on occurrence of cladoceran tumors; and (e) the determination of precise toxins responsible for the inhibition of zooplankton function and behavior.