Long-Term Memory Deficits in Schizophrenia: Primary or Secondary Dysfunction?

Long-term memory impairment is often found in schizophrenia. The question remains whether this is caused by other cognitive deficits. One hundred eighteen first-episode patients were compared with 45 control participants on several memory tasks. The role of processing speed and central executive functions on memory performance was examined with regression analysis for all participants and for patients separately. Deficits were found in general verbal learning performance and retrieval in episodic memory and semantic memory. Processing speed reduced disease-related variance in all memory variables. Coordination, organization of information, and speed of processing were the best predictors for long-term memory deficits in patients. The amount of explained variance, however, is small, especially in general verbal learning performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Compressive strength and failure types of cusp replacing direct resin composite restorations in previously amalgam-filled premolars versus sound teeth

This study evaluated the fracture resistance of cusp replacing direct resin composite restorations (DCR) in premolars that had been previously filled with amalgam mesial–occlusal–distal (MOD) restorations and compared their fracture resistance with those made on sound dentin and intact teeth. Recently extracted human premolars with either MOD amalgam restorations or sound/intact ones were selected for the study. Cavities with cusp reduction were made for the following groups: (a) Group 1: DCRs on previously amalgam-affected dentin (n = 11), (b) Group 2: DCRs on sound dentin (n = 10), and (c) Group 3: intact premolars (n = 9). Teeth in Groups 1 and 2 were restored with a 3-step etch and rinse adhesive (Quadrant Unibond) and filled with hybrid composite (Clearfil Photo Posterior). All specimens were thermocycled for 5000 cycles (5–55 °C). The buccal cusps of the teeth were loaded until fracture under compression at 45° to the long axis of the teeth in a universal testing machine (1 mm/min). Data (N) were statistically analyzed using one-way ANOVA and Student’s t-test (α = 0.01). Intact teeth (Group 3) showed significantly higher fracture resistance (893 ± 196) compared to both restored groups (p < 0.01). No significant difference was found between the DCRs made on amalgam-affected dentin (Group 1: 607 ± 166) and sound dentin (Group 2: 588 ± 183) (p > 0.01). More than half of the teeth of Groups 2 and 3 showed unrepairable fractures with pulp exposure.     

Introduction of a robustness coefficient in optimization procedures: Implementation in mixture design problems Part II: Some practical considerations

The influence of a number of parameters on the behaviour of the robustness coefficient, introduced in Part I, is considered here using an artificial data set. The application of this robustness coefficient with multi-criteria decision making is demonstrated with a real data set.     

Automating strategies of emergency operation for optimal shutdown in pressurized water reactors

In this paper, the automating strategies of emergency operation are proposed for achieving optimal shutdown in pressurized water reactors. These strategies can make emergency operation optimal, and as well they considerably lengthen the operator response time. Decision making and control are investigated in order to develop the automating strategies. In decision-making, diagnostic trees are established to automate the diagnostic tasks for selecting appropriate emergency operations, and the decision-making procedure is developed to automate some decisions which must be made on a plant- and event-specific basis. In control, cooldown is planned by establishing operational goals, forming strategies, and specifying operational means and constraints. The reference set points of the controlled parameters are adaptively adjusted through fuzzy reasoning for optimal cooldown and depressurization. The validation of the proposed strategies was carried out using the micro-simulator for the Kori Unit 2 with steam generator tube rupture events. The results indicated that the automated emergency operation successfully drove the plant at full power to a cold shutdown state with all the operational constraints satisfied.     

Manufacture of one-piece automotive drive shafts with aluminum and composite materials

The natural bending frequency of a torque transmission shaft can be increased without reducing the torque transmission capability if the shaft is made using both carbon fiber composite and aluminum: the former increases the natural bending frequency and the latter sustains the applied torque. The high natural bending frequency of a shaft makes it possible to manufacture the drive shaft of passenger cars in one piece.

In this work, a hybrid one-piece drive shaft composed of carbon fiberepoxy composite and aluminum tube was manufactured by co-curing the carbon fiber on the aluminum tube.

The fabricational thermal residual stresses due to the coefficient difference of thermal expansions of aluminum and carbon fiber composite were eliminated by applying a compressive preload to the aluminum tube before the co-curing operation.

From the dynamic tests, it was found that the first natural bending frequency and the minimum static torque transmission capability of the hybrid shaft were 9000 rpm and 3550 Nm, respectively, and the shaft did not fail until 10⁷ cycles under a dynamic load of ± 500 Nm.