Silicon implanted super low-noise GaAs MESFET

Super low-nose GaAs MESFETs have been fabricated using direct ion implantation into undoped LEC substrates. Microwave results at 12 GHz include a noise figure of 1.3 dB, with an associated gain of 10.3 dB and a maximum available gain of 14.9 dB.     

Dimensions of creativity in children's drawings: A social-validation study.

Creative drawings of 3 preschool girls (3 and 5 yrs old) were modified using reinforcement procedures in a multiple baseline design. Clear changes were produced in the diversity of color and form. When selected drawings were shown to adult judges, higher ratings of creativity were given for drawings with increased form diversity but not for drawings with increased color diversity. Results are discussed in terms of the role of social validation in defining and encouraging creativity. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infantile trauma, genetic factors, and adult temperament.

"This investigation was concerned with the effects of infantile trauma upon adult temperament, the influence of genetic factors upon temperament, and the possibility of an interaction between early experience and gene structure in their influence upon adult behavior." With mice as the Ss, evidence was obtained which indicated that: genetic factors influence emotionality, timidity, and motility in mice; infantile trauma influences emotionality; and there is an interaction effect of genetic and traumatic factors on timidity. The results are related to Freudian theory. (20 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An evaluation of the effectiveness of forward facing child restraint systems

The objective of this study was to determine the effectiveness of forward facing child restraint systems (FFCRS) in preventing serious injury and hospitalization to children 12-47 months of age as compared with similar age children in seat belts. Data were obtained from a cross-sectional study of children aged 12-47 months in crashes of insured vehicles in 15 states, with data collected via insurance claims records and a telephone survey. Effectiveness estimates were limited to those children between 12 and 47 months of age seated in the back row(s) of vehicles, restrained in FFCRS, regardless of misuse, or seat belts of all types and usage. Completed survey information was obtained on 1207 children, representing 12632 children in 11619 crashes between 1 December 1998 and 31 May 2002. Serious injuries occurred to 0.47% of all 12-47-month olds studied, including 1.72% of those in seat belts and 0.39% of those in child restraint systems. The risk of serious injury was 78% lower for children in FFCRS than in seat belts (odds ratio (OR) = 0.22, 95% confidence interval (CI) = 0.11-0.45, P = 0.001). The risk of hospitalization was 79% lower for children in FFCRS than in seat belts (OR = 0.21, 95% CI = 0.09-050, P = 0.001). There was no difference between the restraint types in preventing minor injuries. As compared with seat belts, CRS are very highly effective in preventing serious injuries and hospitalization, respectively. This effectiveness estimate is substantially higher than older estimates, demonstrating the benefits of current CRS designs. These results provide those educating parents and caregivers population-based data on the importance of child restraint use.     

Acute healthcare utilization by children after motor vehicle crashes

This study, describing the overall patterns of acute healthcare resource utilization by child crash victims (age 15 years and younger), was conducted between 28 July 1999 and 30 November 2000 as part of an on-going large-scale, child-specific crash surveillance system, Partners for Child Passenger Safety: insurance claims from 15 states and the District of Columbia function as the source of subjects, with telephone survey and on-site crash investigations serving as the primary sources of data. A probability sample of 4862 eligible crashes with 7368 child occupants formed the study sample. Our results suggest that for every 1000 children involved in crashes, 3 are hospitalized; 108 are treated and released from an emergency department (ED); 48 are evaluated in a physician's office, urgent care center, or other facility; and 841 receive no care at all. Comprehensive surveillance systems for motor vehicle crashes must capture children treated in physicians' offices, emergency departments, and other healthcare facilities in order to provide accurate estimates of the impact on the health care system related to motor vehicle trauma.     

Protecting the child's abdomen: a retractable bicycle handlebar

A surveillance system in the Emergency Department of a level 1 pediatric trauma center previously identified minor bicycle crashes as a cause of serious child abdominal injury. A discordancy exists between the apparently minor circumstances and serious injuries sustained by child bicyclists who impact bicycle handlebars. The objective of this work was to redesign the bicycle handlebar to reduce the forces transmitted to the child's abdomen during an impact with the handlebars. A retractable handlebar consisting of a spring–mass–damper system was designed to retract and absorb the majority of energy at impact (Patent pending). Because the child remains in contact with the bar after impact, the retracting system also includes a mechanism to damp the outward motion of the handlebar. This prototype will reduce the forces at impact by 50% in a collision similar to those discussed above. A unique methodology of translating research findings into product design produced a novel handlebar that absorbs significant energy that otherwise would be transferred to the child's abdomen when impacting the handlebar.     

Ultrasonically set novel NVC-containing glass-ionomer cements for applications in restorative dentistry

The objective of this study is to investigate the effects of application of ultrasound on the physical properties of a novel NVC (N-vinylcaprolactam)-containing conventional glass-ionomer cement (GIC). Experimental GIC (EXP) samples were made from the acrylic acid (AA)–itaconic acid (IA)–NVC synthesized terpolymer with Fuji IX powder in a 3.6:1 P/L ratio as recommended by the manufacturer. Specimens were mixed and fabricated at room temperature and were conditioned in distilled water at 37°C for 1 day up to 4 week. Ultrasound (US) was applied 20 s after mixing by placing the dental scaler tip on the top of the cement and applying light hand pressure to ensure the tip remained in contact with cement without causing any deformation. Vickers hardness was determined using a microhardness tester. The working and setting times were determined using a Gillmore needle. Water sorption was also investigated. Commercial Fuji IX was used as control for comparison (CON). The data obtained for the EXP GIC set through conventional set (CS) and ultrasonically set (US) were compared with the CON group, using one-way ANOVA and the Tukey multiple range test at α = 0.05. Not only ultrasonic (US) application accelerated the curing process of both EXP cement and CON group but also improved the surface hardness of all the specimens. US set samples showed significantly lower water sorption values (P < 0.05) due to improved acid–base reaction within the GIC matrix and accelerated maturation process. According to the statistical analysis of data, significant increase was observed in the surface hardness properties of CS and US specimens both in EXP samples and the CON groups. It was concluded that it is possible to command set GICs by the application of ultrasound, leading to GICs with enhanced physical and handling properties. US application might be a potential way to broaden the clinical applications of conventional GICs in restorative dentistry for procedures such as class V cavity restorations.     

Power conversion in concentrating photovoltaic systems: central,string, and micro‐inverters

In this paper, concentrating photovoltaic (CPV) systems coupled with various inverter configurations are modeled, compared, and tested. Because CPV systems use optics to concentrate sunlight onto highly efficient PV cells, the systems are affected not only by mismatches in the I–V characteristics among individual PV cells but also by the electro‐optical mismatches of each concentrator. The best way to minimize power losses by these mismatches is having higher quality controls in aligning at the time of manufacturing and installation. To mitigate the power losses when mismatches are present, electrical components can be considered at the expense of additional cost. The developed models for central, string, and micro‐inverters allow an accurate estimation of power losses in CPV systems and can be used to find an optimum solution for various power conversion schemes on the basis of the given mismatch conditions. Simulation results show that a CPV system with micro‐inverters outperforms a CPV system with conventional inverters. Experimental test results under normal operation validate that power losses in a CPV system can be reduced by more than 5% by using the micro‐inverter scheme. Copyright © 2013 John Wiley & Sons, Ltd.     

Performance Modeling of MANET Interconnectivity

The proliferation of mobile wireless computing devices and the increasing usage of wireless networking have motivated substantial research in mobile ad hoc networks (MANETs). In addition, much has also been done to link autonomous MANETs to the Internet, and as MANETs become more prevalent, the need to interconnect multiple MANETs becomes increasingly important too. However, direct interconnection of MANETs has rarely been studied. In this paper, we first report an experimental study on the performance of interconnected MANETs running two different routing protocols, viz., the Ad hoc On-Demand Distance Vector (AODV) and Optimized Link State Routing (OLSR) protocols, which represent the two major categories, and show that with the use of multiple gateways, it is possible to viably interconnect multiple networks running different MANET routing protocols. We then follow with a simulation study to evaluate the performance in large networks, which not only validates the scalability of the proposed scheme, but also helps to identify various problems that were not apparent in small experimental networks.