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J C Randolph

Publications and source records attributed to J C Randolph.

4 recordsLinked to original sources
PubMed2001

Nitrogen deposition to and cycling in a deciduous forest.

The project described here seeks to answer questions regarding the role increased nitrogen (N) deposition is playing in enhanced carbon (C) sequestration in temperate mid-latitude forests, using detailed measurements from an AmeriFlux tower in southern Indiana (Morgan-Monroe State Forest, or MMSF). The measurements indicate an average atmosphere-surface N flux of approximately 6 mg-N m(-2) day(-1) during the 2000 growing season, with approximately 40% coming from dry deposition of ammonia (NH3), nitric acid (HNO3), and particle-bound N. Wet deposition and throughfall measurements indicate significant canopy uptake of N (particularly NH4+) at the site, leading to a net canopy exchange (NCE) of -6 kg-N ha(-1) for the growing season. These data are used in combination with data on the aboveground C:N ratio, litterfall flux, and soil net N mineralization rates to indicate the level of potential perturbation of C sequestration at this site.

Ammonia↗
PubMed1980

Organochlorine residues in fish of Lake Texoma, October 1979.

Fillets from 99 fish, representing 11 species and three areas within Lake Texoma, were examined for residues of common organochlorines. Statistical analyses were conducted to determine the relationship of residues in fish fillets to trophic level and to geographical location of the sample. Most species contained PCBs at levels up to 100 ng/g and p,p'-DDE as high as 127 ng/g. p,p'-TDE and o,p'-DDT were not found in carnivores, but were present in herbivores and detritivores in amounts up to 36 ng p,p'-TDE/g and 17 ng o,p'-DDT/g. Heptachlor also was not found in carnivores, but was present as high as 37 ng/g in the other two classes. Chlordane ranged to 24 ng/g and was detected in all trophic levels. Dieldrin and p,p'-DDT were present in detritivores and carnivores up to 144 ng dieldrin/g and 410 ng p,p'-DDT/g. Neither substance was found in herbivores. Mirex, endrin, and heptachlor epoxide were present only at low levels. Statistically significant differences (P = 0.05) were found between trophic levels for seven of the eleven organochlorine compounds. No correlation (P = 0.05) was found between fillet concentrations of any parameter and geographical location of the sample.

Animals↗
PubMed1976

Bilateral total hip arthroplasty: a simultaneous procedure.

Fifty patients undergoing bilateral total hip replacement as a simultaneous procedure at the Indiana University Medical Center were compared with 50 patients undergoing unilateral total hip replacement. There was an increase in phlebitis and myositis ossificans in the patients undergoing bilateral total hip replacement and while their range of motion was less, there was no difference in mortality with one death in each group. The hospital time for patients in the bilateral group averaged 1 week longer than for those with unilateral hip replacement. The operating time and blood loss in patients of the bilateral group was approximately twice that of patients in the control group. There have been no infections as yet in the bilateral group. On the basis of these preliminary results, we can consider bilateral total hip arthroplasty feasible although it carries a slightly increased risk.

Adult↗