Steady-state measurements of respiration rate with an oxygen electrode

An oxygen electrode was developed which measures steady-state respiration rates in a volume of 0.25 ml and at oxygen concentrations as low as 0.1 [mu]. The steady state was achieved by pumping air-equilibrated buffer into the respirometer at various rates. The method is most suitable for tissue slices.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22139/1/0000568.pd

Measurement of oxygen partial pressure within soybean nodules by oxygen microelectrodes

The internal pO 2 of soybean ( Glycine max Merr.) nodules was measured with oxygen microelectrodes. For nodules in air at 23°, the pO 2 decreased sharply across the nodule cortex, and was too low to measure in the central tissue. At 1° in 1.0 atm O 2 , the pO 2 in the central tissue was measurable, and was approximately uniform from the center to the edge of the central tissue. This uniformity was probably due to the intercellular air spaces of the central tissue, since infiltrating the spaces with water substantially decreased the pO 2 in the central tissue. The results strongly suggest that most of the resistance to O 2 diffusion into the nodule occurs within the cortex.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47462/1/425_2004_Article_BF00388335.pd

Development of a photosynthesis model with an emphasis on ecological applications

Photosynthesis was measured in leaves of Phaseolus vulgaris and analyzed according to the set of equations outlined previously by Tenhunen et al. (1976).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47716/1/442_2004_Article_BF00582889.pd

Results from a Search for Light-Mass Dark Matter with a P-type Point Contact Germanium Detector

We report on several features present in the energy spectrum from an ultra low-noise germanium detector operated at 2,100 m.w.e. By implementing a new technique able to reject surface events, a number of cosmogenic peaks can be observed for the first time. We discuss several possible causes for an irreducible excess of bulk-like events below 3 keVee, including a dark matter candidate common to the DAMA/LIBRA annual modulation effect, the hint of a signal in CDMS, and phenomenological predictions. Improved constraints are placed on a cosmological origin for the DAMA/LIBRA effect.Comment: 4 pages, 4 figures. v2: submitted version. Minimal changes in wording, one reference adde