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Biomedical subjects

J Bogen

Publications and source records attributed to J Bogen.

6 recordsLinked to original sources
PubMed2001

The impact of a hydroelectric power plant on the sediment load in downstream water bodies, Svartisen, northern Norway.

When the Svartisen hydroelectric power plant was put into operation, extensive sediment pollution was observed in the downstream fjord area. This paper discusses the impact of the power plant and the contribution from various sources of sediment. Computation of the sediment load was based on samples collected one to four times per day. Grain size distribution analyses of suspended sediments were carried out and used as input in a routing model to study the movement of sediments through the system. Suspended sediment delivered to the fjord before the power station was constructed was measured as 8360 metric tons as an annual mean for a 12-year period. During the years 1995-1996 when the power plant was operating, the total suspended load through the power station was measured as 32609 and 30254 metric tons, respectively. Grain size distribution analyses indicate a major change in the composition of the sediments from 9% clay before the power plant was operative to 50-60% clay afterwards. This change, together with the increase in sediment load, is believed to be one of the main causes of the drastic reduction in secchi depths in the fjord. The effect of the suspended sediment load on the fjord water turbidity was evaluated by co-plotting secchi depth and power station water discharge. Measurements during 1995 and 1996 showed that at the innermost of these locations the water failed to attain the minimum requirement of 2 m secchi depth. In later years secchi depths were above the specified level. In 1997 and 1998 the conditions improved. At the more distal locality, the conditions were acceptable with only a few exceptions. A routing model was applied to data acquired at a location 2 km from the power station in order to calculate the contributions from various sediment sources. This model indicated that the contribution from reservoir bed erosion dominated in 1994 but decreased significantly in 1995. Future operation of the power station will mostly take place with a high water level in the reservoir and is likely to result in acceptable water quality in the fjord. However, during periods of low drawdown, sediment pollution may again become a problem.

Environmental Monitoring↗
PubMed2001

Effectiveness of the "teaching the teachers" diagnostic US training program.

RATIONALE AND OBJECTIVES: The "Teaching the Teachers" training program was meant to establish standardized ultrasound education programs worldwide, reaching the largest possible number of physicians. The authors performed this study to evaluate the results of this training. MATERIALS AND METHODS: An open-ended test question format (ie, uncued testing) that would evoke responses from physicians in a manner ensuring the highest fidelity with a real clinical setting was selected. An examination was administered at the beginning and the end of the program and then again 6 months later to assess baseline knowledge, changes in knowledge, and knowledge retention, respectively. RESULTS: Scores on entry and end-of-program examinations were available for 112 participants. The mean entry test score was 35%, and the mean end-of-program examination score was 73%. All changes in scores were statistically significant (P < .001) as determined with paired t tests. Follow-up examinations were available for 27 of the 112 participants at the time of the analysis. On these examinations, mean total test scores increased by nearly 4 percentage points. Although follow-up test scores were available for only 27 participants, these mean test scores were comparable to those reported for the entire group on the end-of-program examination. CONCLUSION: The examinations administered at the end of the 3-month program showed marked improvement compared with the baseline assessment. That this improvement remained stable over 6 months indicates the success of the educational process.

Curriculum↗
PubMed1998

Different psychological status in the two hemispheres of two split-brain patients.

Questions of a psychological nature were presented to two split-brain patients from the California series encouraging each hemisphere to respond simultaneously and independently. The responses of both patients indicated that their hemispheres were responding independently. For the first patient, his right hemisphere appeared to be more disturbed than his left by childhood memories of being bullied. The right hemisphere of the second patient seemed to regard himself more positively, but it also seemed to feel more negative emotions such as loneliness and sadness. We discuss the possible significance of the findings.

Dominance, Cerebral↗
PubMed1991

Trends in length of stay and rates of readmission in Massachusetts: implications for monitoring quality of care.

In this study, we examined lengths of stay and readmission rates for all Medicare patients discharged from Massachusetts acute care hospitals from October 1982 through September 1986. Using multivariate time series models, we controlled for case mix and assessed trends over time and the impact of prospective payment on lengths of stay and rates of readmission within 7, 14, and 30 days of discharge. We examined patterns for patients overall and for those admitted initially with one of several specific medical conditions or for a surgical procedure. Over the four years, lengths of stay decreased by 25% overall and by 12% to 38% for the individual conditions studied (all p less than .05). A small part of this decrease was associated with prospective payment. Overall readmission rates within 7 and 14 days increased by approximately 10% (p less than .05), although the increase was not statistically associated with prospective payment. Readmission rates for individual medical and surgical conditions were not significantly changed. Further study should assess whether the change in overall rates reflects lower quality care.

Abstracting and Indexing↗