Biomedical subjects

D Policansky

Publications and source records attributed to D Policansky.

3 recordsLinked to original sources

PubMed1999

Revisiting the commons: local lessons, global challenges.

In a seminal paper, Garrett Hardin argued in 1968 that users of a commons are caught in an inevitable process that leads to the destruction of the resources on which they depend. This article discusses new insights about such problems and the conditions most likely to favor sustainable uses of common-pool resources. Some of the most difficult challenges concern the management of large-scale resources that depend on international cooperation, such as fresh water in international basins or large marine ecosystems. Institutional diversity may be as important as biological diversity for our long-term survival.

Conservation of Natural Resources↗

PubMed1981

Sex choice and the size advantage model in jack-in-the-pulpit (Arisaema triphyllum).

Arisaema triphyllum is a perennial herb whose sex and size often change from one growing season to the next. The proportional gain in reproductive success (RS) with size is much greater for female (carpellate) plants than it is for male (staminate) plants. I constructed RS-size curves for males and females; the curves intersect at a point t = 398 mm. According to theory derived from the size advantage model, t is the point below which the plants should be male and above which they should be female. Plots of size-frequency distributions of males and females show that below 380 mm the proportion of males is greater than the proportion of females, whereas above that point the proportion of females is greater than the proportion of males. Thus prediction and observed results are in very close conformity.

Journal Article↗

PubMed1970

"Sex ratio" in Drosophila pseudoobscura: spermiogenic failure.

Contrary to earlier reports, testes of "sex ratio" Drosophila pseudoobscura males have only half as many sperm per bundle as testes of normal males do. This fact, determined from electron micrographs, indicates that the functional pole hypothesis is not applicable to the action of "sex ratio."

Animals↗