Characteristics of bacterial clearance were investigated in the
purple sea urchin, Strongylocentrotus purpuratus (Echinodermata:
Echinoidea). Primary clearance kinetics were determined for three
bacteria, a marine Gram negative motile rod, a marine Gram positive non-motile
rod, and a fresh water fish pathogen, Aeromonas salmonicida.
Various doses of live bacteria were injected...
The objective of the present research was to determine, by use of the progesterone receptor antagonist RU-486, whether progesterone by autocrine/paracrine action suppresses phosphatidylinositol hydrolysis, and thus, the production of prostaglandin F2a during the midluteal phase of the estrous cycle in ewes. Two experiments were performed. Experiment 1 consisted of...
PN-specific, absolute, and Chl a-specific nitrate uptake rates were measured during two upwelling seasons and one winter off Oregon. Although PN-specific and absolute uptake rates showed no dependence on nitrate concentration, Michaelis-Menten kinetics applied when the uptake rates were normalized to Chl a. Chl a-specific nitrate uptake rates were saturated...
Chlorophyll a concentrations were measured as a function of depth from 28 to 48°N along 152°W in March 1991 with Whatman GF/F and 0.2‐µm Nuclepore filters. Surface Chl a concentrations measured with 0.2‐µm Nuclepore filters were up to fourfold higher than those measured with Whatman GF/F filters. The largest difference...
Ammonium uptake and regeneration rates were measured in time course experiments with 15N as a tracer. Both ammonium uptake and regeneration rates measured over 12 to 18 h remained essentially constant. However, as the length of the incubations increased the amount of usable data decreased dramatically due to substrate depletion...
Several studies in recent years have demonstrated that upper-division students struggle with the
mathematics of thermodynamics. This paper presents a task analysis based on several expert attempts
to solve a challenging mathematics problem in thermodynamics. The purpose of this paper is twofold.
First, we highlight the importance of cognitive task...
This revision updates information on susceptibility of grapevines to several common herbicides used in agricultural production. Color photos illustrate injury symptoms. The publication provides practical measures that vineyard owners and their neighbors can take to reduce the risk of herbicide drift and injury to grapes.
Prediction of year-class strength is a critical challenge for fisheries managers. Theoretically,
predictions of recruitment should be better when they are based on estimates of cohort
size taken close to the age of recruitment and may improve if the effects of environmental factors
that influence pre-recruit mortality are accounted for....
Published March 1987. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog