Deadlock detection in distributed systems

The author describes a series of deadlock detection techniques based on centralized, hierarchical, and distributed control organizations. The point of view is that of practical implications. An up-to-date and comprehensive survey of deadlock detection algorithms is presented, their merits and drawbacks are discussed, and their performances (delays as well as message complexity) are compared. Related issues such as correctness of the algorithms, performance of the algorithms, and deadlock resolution, which require further research are examined     

The induction and expression of IgA anti-DNP antibodies in rat bile and secretions

Pregnant rats were immunized with dinitrophenylated type III-pneumococcal vaccine by the intravenous, gastric, or intramammary routes. Anti-DNP antibody responses in the IgA, IgG and IgM isotypes were measured in serum, secretions and bile. Gastric intubation was most effective at eliciting IgA antibody responses in bile and secretions, whereas the other routes were more effective at inducing IgG responses in serum and bile. IgM antibody responses were infrequent and were found in fluids most closely associated with the immunization route. Isoelectric focusing studies of IgA antibodies appearing in secretions and bile revealed that the gastric route consistently elicited antibody spectrotypes with shared components. Intravenous and intramammary immunization resulted in IgA spectrotypes possessing less homology, suggesting that these protocols lead to independent antibody responses triggered in spleen, draining lymph nodes, or secretory sites. After gastric stimulation, the appearance of IgA antibodies with identical spectral components in secretions and bile favours the concept that IgA precursor cells with identical clonotype potential migrate from the gastrointestinal area to secretory sites. Antibody expression in bile appears to result from the selective transfer of IgA populations gaining access to serum after synthesis at a secretory site.     

Management of cervical neoplasia with colposcopy

During a 44-month period the introduction of colposcopy to a metropolitan dysplasia clinic resulted in 1, 144 colposcopic examinations on 442 patients. Agreement between colposcopically directed biopsy and final diagnosis was found in 84%, and directed biopsy revealed the most advanced lesion in 42.5%. Satisfactory colposcopy was performed on 93% of patients, and some degree of histologic abnormality was obtained in 86% of patients with colposcopic abnormalities. Undetected invasive cervical cancer occurred in both cervical conization and colposcopic examinations with equal frequency. Endocervical curettage detected two cases of occult invasive cancer, and increased use of this procedure is recommended. Guidelines for management of cervical neoplasia are suggested.     

Why behavior analysts should study emotion: the example of anxiety

Historically, anxiety has been a dominant subject in mainstream psychology but an incidental or even insignificant one in behavior analysis. We discuss several reasons for this discrepancy. We follow with a behavior-analytic conceptualization of anxiety that could just as easily be applied to emotion in general. Its primary points are (a) that languageable humans have an extraordinary capacity to derive relations between events and that it is a simple matter to show that neutral stimuli can acquire discriminative functions indirectly with no direct training; (b) that private events can readily acquire discriminative functions; (c) that anxiety disorders seem to occur with little apparent direct learning or that the amount of direct learning is extraordinarily out of proportion with the amount of responding; and (d) that the primary function of anxious behavior is experiential avoidance. We conclude that the most interesting aspects of anxiety disorders may occur as a function of derived rather than direct relations between public events and overt and private responses with avoidance functions. Implicit in this conclusion and explicit in the paper is the assertion that anxiety is a suitable subject for behavior-analytic study.     

The clinical significance of gadolinium enhancement of lumbar disc herniations and nerve roots on preoperative MRI

The clinical significance of preoperative gadolinium DPTA enhancement around disc herniations and in the epidural space on MRI is not clear. The relation of nerve root enhancement to dysfunction also remains controversial. To investigate the clinical significance of contrast enhancement we looked at the symptoms and signs and gadolinium DPTA-enhanced images of 71 consecutive surgical candidates in a standardised fashion. Annular rupture and disc enhancement were found to be closely related, and correlated with sensory loss and paresis, respectively. Nerve root enhancement was found to be related to neurological deficits in general and sensory impairment in particular.