Jens Thorup

Three-year study of benthic algal spring bloom development in a small, Danish lowland stream

Seasonal development of benthic algae was studied over a three-year period in a small, nutrient-rich lowland stream to investigate inter-annual variation in the algal spring bloom and differences in algal biomass regulation on two different substrata: fine-grained sediments and stones. The algal spring bloom was initiated when irradiance at the sediment surface exceeded 7 mol photons m-2 d-1 and mean water velocity was concomitantly below the threshold for bed load transport in the stream. Large inter-annual and substratum-dependent differences in peak algal biomass were observed, thus suggesting that different parameters regulate algal biomass development on the two substrata. On fine-grained sediments algal biomass development was predominantly coupled to light availability, while on stony substrata algal composition and peak biomass might be affected by invertebrate grazing.

Dihydroergotamine in postoperative ileus

The effects of dihydroergotamine (DHE) on postoperative ileus after major abdominal surgery were studied. Forty‐one patients received 0.5 mg DHE subcutaneously twice a day from the day of surgery to the seventh postoperative day. Thirty‐three patients served as controls. There were no significant differences in the time to the first postoperative passage of flatus or delivery of stools nor in the quantity of laxatives given. It is concluded that DHE does not reduce the duration of postoperative ileus.

Benthic algal biomass in an unshaded first-order lowland stream: distribution and regulation

The vertical distribution of algal biomass in the bed sediment and the seasonal development of benthic algae on stones and fine-grained sediments were studied in a small unshaded stream. In addition, field experiments were conducted on the role of irradiance and phosphorus in regulating algal biomass.We found that algal biomass was high at a sediment depth of ten centimetres. Comparison of studies on algal biomass where different depths of the sediment are used should therefore be made with caution. Substrata-dependent differences in algal biomass development were substantial. While algal biomass development on stones was controlled by macroinvertebrate grazing, that on the fine-grained sediment followed the dynamics of incident irradiance, but was attenuated by sediment rebedding. Because of the high grazing pressure on algal biomass on stony substrata, no significant response to phosphorus enrichment was attained. In contrast, algal biomass development on fine-grained sediments was phosphorus-limited. Heavy shading of the fine-grained sediments did not significantly affect algal biomass development, thus suggesting that phosphorus limitation prevents algae from fully utilizing the light resource in this stream.

Convalescence after inguinal herniorrhaphy.

BACKGROUND The aim of this investigation was to evaluate factors influencing the length of convalescence after ambulant inguinal hernia repair. METHODS One hundred and twenty-three patients were followed up to assess when they returned to work, considered that they had regained full working capacity, and resumed leisure time activities. The length of sick leave was recommended on the basis of the load of the occupation. RESULTS Half of the patients had a longer sick leave than recommended by the surgeon. Active and heavy work showed an independent significant positive correlation to the length of sick leave. Median sick leave among these patients was 42 days, which was the time they considered that they had regained full working capacity and 1 week after they had resumed their leisure time activities. Median sick leave among patients with sedentary or moderately active work was 9 days before regaining full working capacity and 12 days before resuming leisure time activities. CONCLUSIONS Other factors than load of work and surgeons advice seem to play a role in the patients decision about when to resume normal activities on the job.