Stability of High-Rate Anaerobic Systems. II: Fuzzy Stability Index

Based on a fuzzy logic method, fuzzy stability index N was proposed to integrate the complex information contained in various system variables and explicitly indicate the departure of a system from normal state. The instability of a system subjected to a shock could be explicitly revealed by its variance of N. Based on the examination of variance of N, the stability of three high-rate anaerobic reactors in the presence of various shocks was quantitatively compared. The comparison results based on N coincided in general with the conclusions obtained from a direct examination of the reactors' performance, but the N comparison method was proven to be much more convenient and explicit as compared with the method of direct examination of the reactors' performance.     

Adult psychological functioning of individuals born with craniofacial anomalies

This study represents an initial investigation into the adult psychological functioning of individuals born with craniofacial disfigurement. A total of 24 men and women born with a craniofacial anomaly completed paper and pencil measures of body image dissatisfaction, self-esteem, quality of life, and experiences of discrimination. An age- and gender-matched control group of 24 non-facially disfigured adults also completed the measures. As expected, craniofacially disfigured adults reported greater dissatisfaction with their facial appearance than did the control group. Craniofacially disfigured adults also reported significantly lower levels of self-esteem and quality of life. Dissatisfaction with facial appearance, self-esteem, and quality of life were related to self-ratings of physical attractiveness. More than one-third of craniofacially disfigured adults (38 percent) reported experiences of discrimination in employment or social settings. Among disfigured adults, psychological functioning was not related to number of surgeries, although the degree of residual facial deformity was related to increased dissatisfaction with facial appearance and greater experiences of discrimination. Results suggest that adults who were born with craniofacial disfigurement, as compared with non-facially disfigured adults, experience greater dissatisfaction with facial appearance and lower self-esteem and quality of life; however, these experiences do not seem to be universal.     

Intraoperative recording of the bulbocavernosus reflex

OBJECTIVE: To demonstrate the feasibility of intraoperative monitoring of the bulbocavernosus reflex (BCR) as an indicator of the functional integrity of sacral nervous structures to aid in preventing their intraoperative injury. METHODS: Intraoperative BCR was elicited by electrical stimulation of the dorsal penile/clitoral nerve in 119 patients anesthetized with propofol, fentanyl, and nitrous oxide, with short-acting relaxant. Thirty-eight patients underwent surgery without risk, whereas 81 underwent surgery with risk of damage to sacral structures. Different patterns of stimuli were applied through silver/silver chloride disc electrodes placed on the dorsal aspect of the penis in males and over the clitoris (cathode) and adjacent labia (anode) in females. Recordings were made from the anal sphincter using intramuscular wire electrodes introduced within a 27.5 gauge needle, with two electrodes each inserted in the right and left hemisphincter muscles. Preoperatively, some patients had minor urinary problems in controlling their sphincters. RESULTS: The BCR was reliably recorded without habituation under this anesthetic regime. Optimal stimulating parameters were found to be double pulses (0.5-ms duration), with an interstimulus interval of 3 ms, stimulating rate of 2.3 Hz, and intensity of 20 mA. With these parameters, it was possible to record the BCR intraoperatively in all patients. Isoflurane and nitrous oxide significantly suppressed the BCR, and muscle relaxant completely abolished it. CONCLUSION: We demonstrated that it is feasible, under certain anesthetic regimes, to intraoperatively monitor the BCR in both children and adults (24 d to 74 yr of age) who did not have significantly affected function in sacral nervous structures.     

Performance enhancement of two-degree-of-freedom controllers via adaptive techniques

This paper generalizes earlier results on adaptive disturbance estimate (innovations) feedback regulation to the case of adaptive tracking, refining some of the techniques and formulations in the process. The adaptations proposed search within the class of all stabilizing two-degree-of-freedom controllers for a nominal plant and minimize a reference signal/disturbance rejection measure. The emphasis in the paper is on issues relevant to the tracking task and simulation results to demonstrate the effectiveness of the approach. The adaptive scheme is based on results concerning the convenient characterization of the class of all stabilizing two-degree-of-freedom controllers in terms of an arbitrary filter Q with a stable proper transfer function matrix Q(s). The fact that the closed-loop transfer matrices are affine in Q(s) permits a straightforward on-line least-squares update of the parameters of the filter Q on-line. The theory for the class of stabilizing controllers is used to set up appropriate signal preprocessing. The direct adaptive schemes proposed turn out to be recursive prediction error schemes which have local convergence properties. When convergent, they ensure enhancement of the performance of a fixed controller in other than the nominal plant case.     

The progression of untreated lumbar kyphosis and the compensatory thoracic lordosis in myelomeningocele

Radiographs of 37 patients with untreated lumbar kyphosis without congenital vertebral anomalies associated with myelomeningocele were analyzed. With an average interval between radiographs of 6.2 years, the kyphosis was noted to increase at a mean rate of 4.3 degrees per year without correlation to its initial magnitude. The compensatory lordosis was more variable and progressed at a mean of 2.5 degrees per year. Children under the age of 2 years were more likely to increase the Cobb angle and the height of their kyphosis. There was an inverse relationship between the height of the kyphus and the lumbar spine height and the resultant growth of each. A modified kyphotic index less than 4 correlated with an increase in the curve and height of the kyphosis and the subsequent desire for surgery. Wide variability in radiographic parameters make predictions for an individual patient difficult.