Semantic failure [of software]

The author offers the opinion that the adoption of the terminology of hardware reliability in the context of software was a terrible, probably unavoidable, and perhaps even necessary, mistake: terrible-because the words cannot have the same meanings in both contexts; and unavoidable-because today there are few systems whose reliability can be assessed without dealing with both     

A technique for segmental rectal and colonic perfusion in humans

To enable a better characterization of pathophysiologic processes in colon and rectum, we have developed a perfusion technique for collection of soluble substances and cells from standardized intestinal segments. A tube with balloons attached to its outer wall was endoscopically introduced into the rectum and sigmoid colon, and its position ascertained fluoroscopically. The balloons delimited two segments, one in the sigmoid colon and one in the rectum. The segments were simultaneously perfused by a buffer at 37 degrees C. After a 30-min rinsing period, perfusate and cells were collected at 20-min intervals. Of 51 attempted perfusions, 45 were successfully completed. Recovered volumes equaled those infused. Leakage from the proximal intestine to the segments was negligible. In 18 healthy volunteers, the mean perfusate concentration from the rectal segment was 57.5 (27.5-120.2) mg/L for albumin, 1.3 (1.0-1.7) micrograms/L for eosinophil cationic protein, 5.1 (2.8-9.5) ng/L for prostaglandin E2, and 61.7 (41.7-89.1) micrograms/L for hyaluronan, and all values were lower in the sigmoid segment. Steady state conditions were achieved from the second perfusion period. The perfusate contained 4-80 x 10(4) cells, more than 95% of which were epithelial cells. The technique is safe, has a good subject compliance, and seems to be a valuable tool in investigations on quantitative release of soluble substances and cells in, e.g., colorectal inflammation.     

Ultrastructural studies of the ileum neobladder

Of 101 women, 15-50 years of age, presenting with vaginal discharge, 34 had bacterial vaginosis and were randomly assigned to a seven-day course of oral treatment with either erythromycin (0.5 g b.i.d.) or metronidazole (0.4 g b.i.d.) in a single-blind, cross-over study. Treatment failure (> or = three clinical signs of bacterial vaginosis) occurred in 13 (81%) of 16 patients given erythromycin, as compared with three (17%) of 18 women treated with metronidazole (p < 0.001). Persistence of Gardnerella vaginalis, Mobiluncus species and/or Mycoplasma hominis was found in 14 of 16 patients treated with erythromycin, and in four of 16 patients treated with metronidazole. Treatment with metronidazole was successful (< or = two clinical signs of bacterial vaginosis) in eight of 10 cases of erythromycin treatment failure. Neither of two cases of metronidazole treatment failure was cured with erythromycin. At three-month follow-up of 31 women, persistence or recurrence of bacterial vaginosis was diagnosed in 11 cases (36%).     

Aggregate Queries Over Conditional Tables

Conditional tables have been identified long ago as a way to capture unknown or incomplete information. However, queries over conditional tables have never been allowed to involve column functions such as aggregates. In this paper, the theory of conditional tables is extended in this direction, and it is shown that a strong representation system exists which has the closure property that the result of an aggregate query over a conditional table can be again represented by a conditional table. It turns out, however, that the number of tuples in a conditional table representing the result of an aggregate query may grow exponentially in the number of variables in the table. This phenomenon is analyzed in detail, and tight upper and lower bounds concerning the number of tuples contained in the result of an aggregate query are given. Finally, representation techniques are sketched that approximate aggregation results in tables of reasonable size.     

Some Aspects of Reliability Growth

Reliability growth is examined with the use of a variant of the Duane model. This variant is based on stepwise growth and avoids some of the mathematical and philosophic dificulties associated with the Duane model. Monte Carlo simulation, while confirming the noisy behavior of reliability growth data, indicates that central tendencies are sufficiently strong to justify the use of Gaussian approximations for analysis of some aspects of growth. Some exact methods and some approximations for parameter estimation are presented.     

Highly sensitive thromboplastins do not improve INR precision

OBJECTIVE: Severe obesity (ie, at least 100% overweight or body mass index > or =40 kg/m2) is associated with significant morbidity and increased mortality. It is apparently becoming more common in this country. Conventional weight-loss treatments are usually ineffective for severe obesity and bariatric surgery is recommended as a treatment option. However, longitudinal data on the long-term outcome of bariatric surgery are sparse. Available data indicate that the outcome of bariatric surgery, although usually favorable in the short term, is variable and weight regain sometimes occurs at 2 years after surgery. The objective of this study is to present a review of the outcome of bariatric surgery in three areas: weight loss and improvement in health status, changes in eating behavior, and psychosocial adjustment. The study will also review how eating behavior, energy metabolism, and psychosocial functioning may affect the outcome of bariatric surgery. Suggestions for additional research in these areas are made. METHOD: Literature review. RESULTS: On average, most patients lose 60% of excess weight after gastric bypass and 40% after vertical banded gastroplasty. In about 30% of patients, weight regain occurs at 18 months to 2 years after surgery. Binge eating behavior, which is common among the morbidly obese, may recur after surgery and is associated with weight regain. Energy metabolism may affect the outcome of bariatric surgery, but it has not been systematically studied in this population. Presurgery psychosocial functioning does not seem to affect the outcome of surgery, and psychosocial outcome is generally encouraging over the short term, but there are reports of poor adjustment after weight loss, including alcohol abuse and suicide. CONCLUSIONS: Factors leading to poor outcome of bariatric surgery, such as binge eating and lowered energy metabolism, should be studied to improve patient selection and outcome. Long-term outcome data on psychosocial functioning are lacking. Longitudinal studies to examine the long-term outcome of bariatric surgery and the prognostic indicators are needed.