Sub-optimal control of a multivariable non-linear chemical reactor using quasilinearization

The performance of a multivariable non-linear stirred tank chemical reactor has been used to compare the practicability of an optimal controller and two types of suboptimal controller. The optimal controller, which by its nature required lengthy calculations, was suitable for open-loop control only and therefore sensitive to modelling errors. By contrast a suboptimal controller, which used the method of quasilinearization to solve the two point boundary value problem, needed only a small amount of computation time and was capable of online implementation. This controller was much less sensitive to modelling errors, and also had the advantage of decoupling the control variables. An extension of this controller incorporated a feedback feature which compensated further for modelling errors and, in addition, unmeasured disturbances. This controller, which is expected to be of interest to the process industries facing inaccurate-model problems, produced responses close to the true optimal response even when the actual model used was in gross error.     

Neuroticism among policemen: An examination of police personality.

Compared the neuroticism scores of college-educated policemen, non-college-educated policemen, and college- and non-college-educated civilians (N = 548), using the Eysenck Personality Inventory and the Rokeach Dogmatism Scale. On the whole, policemen scored lower on neuroticism when compared with nonpolice citizens. Noncollege police were significantly less neurotic than college and noncollege civilians on the Eysenck but not on the Rokeach scale. It is concluded that neuroticism was not a major characteristic of this group of policemen. (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retrospective study of the diagnostic criteria in a lead-poisoning survey of waterfowl

A review of childhood injuries at the Wesley Guild Hospital, a component of Obafemi Awolowo University Teaching Hospital Complex, Ile-Ife, Nigeria, showed that 1,471 patients seen in the children's emergency room during a period of 4 years (1992-1995) were there as a result of trauma, representing 9% of all patients seen. The case notes and accident and emergency cards of 1,224 were available for review. Ages ranged from 2 months to 15 years, with a mean of 6.9 years, and 40% of the patients were between 5 and 10 years of age. More males were affected than females, with a ratio of 1.5:1. Road traffic crashes were the most common causal factor, responsible for 324 injuries (26.5%). About 90% of these were pedestrians knocked down by automobiles and motorcycles. Passengers accounted for about 10% of the cases. Falls occurred in 305 patients (25%); 229 patients fell while on level ground either playing or running, accounting for 75%. There were 122 patients (10%) with misplaced foreign bodies; about 60% of these were recovered from the ears, and 26.3% from the nostrils. Edible seeds were the most common foreign bodies, followed by beads. Injuries from bites occurred in 108 patients, with dog and snake bites taking the lead. Burns, mainly from scalding, occurred in 89 patients. Other rare injuries were knife wounds, gunshot wounds, and injuries resulting from assaults. The home was the most common site of injury (570 patients, 46.7%) followed by streets or roadways (363 patients, 29.7%); 19.5% of injuries occurred at school. The most common anatomic region affected was the head and neck, followed by the limbs. One hundred ninety-seven patients (16%) had bony fractures, femurs being the most affected bone. Head injury was seen in 104 patients, representing 8.5%, although only 17 of these injuries were severe. There were 10 cases of abdominal injury and 9 cases of chest injury, representing 0.8 and 0.7%, respectively. Wound infection occurred in 6.4% of the patients. Death occurred in 19 patients, accounting for 1.6%; 10 of these patients had severe head injuries. Road traffic injuries and burns accounted for the greatest number of complications. The findings of this study suggest that trauma is an important factor in childhood morbidity and mortality in our environment, with road traffic injuries taking the lead. Preschool pedestrian children were most commonly affected, the majority of them on errands for their parents. We believe that the majority of these injuries are preventable.     

Behind closed doors: Pithy management in-service for case managers.

Presents an April Fool's parody of the first half-day of an in-service program on empowerment for case managers (CMs) vis-a-vis mental health care providers. The in-service training employs pithy management theory and techniques. Basic principles for CMs include setting limits, providing direction; commenting on process, interpreting resistance, and providing personal guidance. A self-affirming, guided imagery exercise is included for developing a positive attitude on a daily basis. Examples are given of relaxed, empowered CMs operating in the styles of Ernestine the Operator, Ernest Hemingway, and Monty Python's Guard. Sample memos to therapists illustrate the application of pithy techniques. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Charles Marville and the Landscapes of the Carrières d’Amérique

Charles Marville’s photographs of Paris preserve the look of streets slated for demolition under Georges-Eugène Haussmann. This article examines his photographs of the Carrières d’Amérique, or America Quarries – gypsum quarries in the outlying Parisian neighbourhood of Belleville. At a time when the rezoning of districts that were formerly extra muros was still controversial, Belleville was seen as a crime-ridden area. Marville’s photographs become documents that refute contemporary narratives of criminality. Borrowing Walter Benjamin’s view that the city ‘opens up’ to the flâneur ‘as a landscape’, the article analyses Marville’s landscapes of the Carrières d’Amérique as images that juxtapose the city, the work site, and the no-man’s land or terrains vagues at Paris’s outer limits.     

Templated pores in hydrogels for improved size selectivity in gel permeation chromatography

The pore structures of cross-linked polyacrylamide gels can be altered by polymerizing in the presence of high concentrations of unreactive, micellar surfactant cosolutes which act as "templates". Removal of surfactant after polymerization is expected to leave pores with the approximate shape and dimensions of the surfactant micelles. A simple model was developed to simulate gel permeation chromatography (GPC) separations of globular proteins on templated gels. The model assumes that the partition coefficient for sieving of a protein is equal to the fraction of gel volume accessible to a sphere with a radius equal to the protein Stokes radius. The total gel volume is considered to include a fraction that is a conventional, random gel matrix and a remaining fraction contributed by templated pores. The pore size distribution of the conventional gel was estimated using the Ogston equation, which approximates the matrix as a random collection of long, thin, rigid fibers. Templated pores were assumed to have a Gaussian distribution of radii centered about some mean determined by the micelle radius. In comparison to conventional media, gels with templated pores are predicted to exhibit more sharply defined exclusion limits and improved resolution over a narrow size range centered on the mean templated pore size. Selectivity and resolution are expected to increase as the volume fraction of templated pores is increased and as the dispersion of templated pore radius is decreased. Small changes in template radius lead to large changes in the molecular weight range of optimal separation of globular proteins. It should be possible to create a series of GPC media that collectively offer high resolution over the molecular weight range of most globular proteins of interest.     

Evidence that levels of presenilins (PS1 and PS2) are coordinately regulated by competition for limiting cellular factors

Mutations in two related genes, PS1 and PS2, account for the majority of early onset cases of familial Alzheimer's disease. PS1 and PS2 are homologous polytopic membrane proteins that are processed endoproteolytically into two fragments in vivo. In the present report we examine the fate of endogenous PS1 and PS2 after overexpression of human PS1 or PS2 in mouse N2a neuroblastoma cell lines and human PS1 in transgenic mice. Remarkably, in N2a cell lines and in brains of transgenic mice expressing human PS1, accumulation of human PS1 derivatives is accompanied by a compensatory, and highly selective, decrease in the steady-state levels of murine PS1 and PS2 derivatives. Similarly, the levels of murine PS1 derivatives are diminished in cultured cells overexpressing human PS2. To define the minimal sequence requirements for "replacement" we expressed familial Alzheimer's disease-linked and experimental deletion variants of PS1. These studies revealed that compromised accumulation of murine PS1 and PS2 derivatives resulting from overexpression of human PS1 occurs in a manner independent of endoproteolytic cleavage. Our results are consistent with a model in which the abundance of PS1 and PS2 fragments is regulated coordinately by competition for limiting cellular factor(s).