The dynamics of integration and separation: ERP, MEG, and neural network studies of immediate repetition effects.

This article presents data and theory concerning the fundamental question of how the brain achieves a balance between integrating and separating perceptual information over time. This theory was tested in the domain of word reading by examining brain responses to briefly presented words that were either new or immediate repetitions. Critically, the prime that immediately preceded the target was presented either for 150 ms or 2,000 ms, thus examining a situation of perceptual integration versus one of perceptual separation. Electrophysiological responses during the first 200 ms following presentation of the target word were assessed using electroencephalography (EEG) and magnetoencephalography (MEG) recordings. As predicted by a dynamic neural network model with habituation, repeated words produced less of a perceptual response, and this effect diminished with increased prime duration. Using dynamics that best accounted for the behavioral transition from positive to negative priming with increasing prime duration, the model correctly predicted the time course of the event-related potential (ERP) repetition effects under the assumption that letter processing is the source of observed P100 repetition effects and word processing is the source of observed N170 repetition effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Vision based navigation system for an endoscope

A vision based navigation system to guide an endoscope inside a human colon has been designed and tested. It uses low level vision techniques to extract two types of navigational landmarks, dark regions and curved contours. Dark regions correspond to the distant inner space of the colon, called the lumen. The curved contours represent occlusions due to the inner colon muscles. A hierarchical search space and environment representation, called the QL-tree, was developed to integrate the visual features and implement the navigation system. It uses multiple quadtrees which are linked at all hierarchical levels. A multiprocessor system was employed to achieve real-time performance. The endoscope navigation system has been used successfully in artificial colon models.     

Liquid phase sintering of tough coated hard particles

Tough coated hard particles (TCHP) are a new microstructure opportunity for designing hard, wear resistant materials at the particle level. As opposed to coating whole devices, TCHP particles are coated at the micrometer level. During wear, these particles constantly present fresh, wear–resistance microstructures that provide a service lifetime not possible with coated devices. Further, fracture toughness is maximized by the uniform tough ligament spacing between hard particles. Such functionality has applications in abrasive wear, wire drawing, metal forming, rolling contacts, and other applications requiring performance over long service times. For the TCHP concept to succeed, new protocols are required for densification during liquid phase sintering. To avoid grain coarsening, dissolution of the coating phase must be minimized while at the same time densification is induced. This unique challenge reduces the amount of densification possible via solution-reprecipitation processes. Thus, special coatings and composition combinations may be required to control densification while preserving the desired coating–core microstructure in the densified product.     

The future of Medicare. Their plans, your practice, Medicare reform, and how it will affect the practice of dermatology

OBJECTIVE: To investigate the relationship between adolescent risk behaviours, taking into account their influence upon one another. DESIGN: Cross-sectional survey utilising a self-completed questionnaire; stepwise logistic regression analyses were carried out, stratified for gender. SETTING: High schools in the Cape Peninsula, South Africa SUBJECTS: 7,340 students from 16 schools in the three major education departments. OUTCOME MEASURES: The outcome variables for each regression model were: cigarette smoking, cannabis smoking, alcohol bingeing, sexual intercourse, knife-carrying at school, walking home at night from beyond the neighbourhood, attempting suicide, and failure to use a seat belt. For each model, 26 risk behaviours served as independent variables. RESULTS: For each model, between 3 and 9 variables qualified for inclusion for each gender. There was a substantial association between many forms of substance abuse. In the previous 12 months, suicidal thoughts or statements of suicidal intent were predictors of a suicide attempt. Several variables involving injury were predictors of exposure to danger in getting home at night, and this was a predictor of substance abuse. Cannabis smoking, alcohol bingeing and exposure to danger in getting home at night were predictors of and were predicted by having had sexual intercourse. CONCLUSION: There are significant relationships between many adolescent risk behaviours, even when the influence of other risk behaviours is taken into account. The probability of adverse sequelae of risk behaviours, such as exposure to danger in getting home at night and sexual intercourse, is increased by the presence of selected other risk behaviours.     

Diffusion-Weighted MRI and Response to Anti-Cancer Therapies

In oncology practice, longitudinal studies are routinely conducted to monitor the size and enhancement of tumors in cancer patients undergoing therapy. Imaging protocols typically use gadolinium-enhanced T₁-weighted images or T₂-weighted images from which tumor size is inferred and tumor response estimated. The past few years have also seen the emergence of diffusion-weighted magnetic resonance imaging (DWMRI) as a potential alternative to monitor therapeutic response (Kauppinen, R.A., NMR Biomed. 2002, 15, 6). The attractiveness of DWMRI resides in its ability to detect local microstructural changes associated with treatment long before their effects are translated into effective size changes. Damage to cell membrane integrity, changes in viscosity, and/or relative size of intra- vs. extracellular compartments all translate into changes in the apparent diffusion coefficient of tumor water measured by DWMRI. This dependence makes DWMRI a particularly sensitive method to detect response to a wide variety of chemotherapeutic agents. This review will focus on the emerging role of DWMRI to monitor the response of tumors to anti-cancer chemotherapies.     

Low-power sensor signal monitoring and impulse radio architecture for biomedical applications

Remote diagnostics of the vital information of a patient and the initiation of necessary actions by the healthcare professionals have resulted in the development of wireless body area network (WBAN). With little to no maintenance, each sensor node within a WBAN must operate with less than 100 μW of power consumption. Impulse radio architecture can be utilized to achieve this goal. This paper reports a low-power transmitter unit consisting of a Data Generator Block, an Impulse Generator Block and a Buffer. The Data Generator Block converts any electrochemical sensor current ranging from 0.2 to 2 μA to digital data. This block consumes a power in the range of 2.575–4.29 μW. The Impulse Generator Block utilizes an RC network to generate impulses of approximately 55 ns duration. Both the Data Generator Block and the Impulse Generator Block can operate with a 1 V supply. Finally, a Buffer circuit, which operates with a 2 V supply, is used to drive a standard 50 Ω load such as an external antenna. The peak current consumption of the impulses is 2.11 mA with a peak output voltage of 72 mV, making it extremely suitable for short range wireless communication. The entire system has been designed and fabricated using a 90 nm standard CMOS process. The average power consumption of the system is only 22.10 μW.     

Earned readiness management for scheduling,monitoring and evaluating the development of complex product systems

How should the development of a complex product system (CPS) be managed in a manner that focuses on process milestones, which is responsive to changes in technology and requirements; based on maturity measures; and applied in an interactive manner, in addition to facilitating timely feedback? This is considered to be an important question in project management. Project management tools and techniques have been inadequate for monitoring technology development in a CPS. If the technologies are not properly matured by a specific period of time, the progress of the project can be in detriment. To address this important gap, the objective of this study is to develop a new maturity-focused methodology for scheduling, monitoring and evaluating the development of a system. We present Earned Readiness Management (ERM) for system scheduling, monitoring and evaluation which was developed and validated using a case study. Future research on ERM is also discussed in this paper.     

Do agonistic motives matter more than anger? Three studies of cardiovascular risk in adolescents.

Objectives: Three motivational profiles have been associated with recurring psychological stress in low-income youth and young adults: Striving to control others (agonistic striving), striving to control the self (transcendence striving), and not asserting control (dissipated striving). Agonistic striving has been associated with elevated ambulatory blood pressure during daily activities. Three studies tested the hypotheses that: (1) agonistic striving is associated with poor anger regulation, and (2) agonistic striving and poor anger regulation interactively elevate blood pressure. Design: Motivational profiles, anger regulation, and ambulatory blood pressure were assessed in a multiethnic sample of 264 urban youth. Main Outcome Measures: (1) anger regulation/recovery during laboratory challenge; (2) anger/blood pressure during daily activities (48 hours). Results and Conclusion: Replication of the profiles in distant cities showed they occur with similar frequency across differences of region, race, and gender. Analyses controlling for body size, race, and gender revealed that individuals with the agonistic striving profile had higher ambulatory pressure, especially during social encounters. They became more openly angry and aggressive when challenged but did not exhibit difficulty regulating anger in the laboratory, nor did they feel angrier during monitoring. However, individuals with the agonistic striving profile who did display poor anger regulation in the lab had the highest blood pressure; deficient self-regulatory capability amplified the positive association between agonistic striving and cardiovascular risk in both genders and all ethnic groups. Although anger is thought to increase cardiovascular risk, present findings suggest that anger and elevated blood pressure are coeffects of agonistic struggles to control others. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Bitumen effects on pipeline hydraulics during oil sand hydrotransport

Oil sand hydrotransport technology has become increasingly important to Syncrude Canada Ltd. and the oil sands industry. Oil sand slurries are complex, multiphase mixtures of bitumen, coarse solids, fine solids, water and air that can exhibit time‐dependent behaviour, wherein pipeline friction losses increase drastically with time. Four separate experimental programs were conducted to study the effect of bitumen on pipeline hydraulics using 100 mm and 250 mm (I.D.) recirculating and once‐through pipeline loops. The results show that pipeline friction losses increase as a bitumen coating forms on the pipe wall. The effect is more pronounced at 50°C, but also occurs at lower temperatures.