Fabrication and Characterization of a Long Wavelength InP HBT-Based Optical Receiver

Development of a high speed photodetector - the InP-based phototransistor (HPT) for use in optical receivers for microwave signal distribution for satellite phased array antennas is addressed. Currently, p-i-n photodetectors are used because of their compatibility with the heterojunction bipolar transistor (HBT), but their performance limits the bandwidth of these optical receivers. The HPT photodetector was investigated here as an alternative photodetector for monolithic integration with heterojunction bipolar transistor amplifiers in long wavelength (1.3 micron), gigahertz (GHz) frequency optical receivers

Can High-risk Older Drivers be Identified in a DMV Setting with a Brief Battery of Functional Tests?

Recent research has indicated that some laboratory measures of functional ability may discriminate between crash-involved and crash-free older adults. However, the ability of these tests to provide the same level of discriminability in a real-world setting such as a Department of Motor Vehicles remains to be established. Therefore, in conjunction with the Maryland Department of Motor Vehicles and the National Highway Traffic Safety Administration, a brief battery of tests was developed and evaluated. The battery contained a number of cognitive tests (e.g., UFOV® subtest 2, the closure subtest of the Motor Free Visual Perception Test [MVPT], Trails A and B, etc.) and physical measures (e.g., Rapid Pace Walk, Head and Neck Rotation, etc.) that prior literature had indicated might be related to crash risk in older adults. Motor Vehicle Administration staff were trained to administer the test battery. Older adults (N=4,173, mean age =69 years) were approached by the staff after license renewal and asked to help evaluate the brief battery. Of the 4,173 older adults approached at the field sites, 2,112 individuals aged 55-96 years of age participated. The primary outcome of interest for this study was the occurrence of an at-fault Motor Vehicle Collision (MVC) following assessment. For members of this sample, the outcome period ranged from 2-3 years. Rate Ratios were determined for each functional variable based upon at-fault crashes adjusted for driving exposure over this period. Univariate analyses revealed that five variables (Age, Walk Time, MVPT, Trails A and UFOV®) were significantly related to crash frequency. These significant variables overlapped with one another to a certain degree, indicating that impaired older drivers score poorly on multiple cognitive assessments. The UFOV® subtest 2 appears to be the most strongly associated within this analysis (RR=3.78, p\u3c .05) and Rapid Pace Walk (RR=1.96, p \u3c .05) remained uniquely related to the frequency of state-reported, at-fault crashes. The role of such a screening battery in field settings such as a DMV will be discussed

Predicting Driving Performance in Older Adults with the Useful Field of View Test: A Meta-Analysis

This investigation examines the Useful Field of View (specifically theUFOV® test), as a predictor of objective measures of driving performance.PubMed and PsycInfo databases were searched to retrieve eight independentstudies reporting bivariate relationships between the UFOV® test and drivingmeasures (driving simulator performance, state-recorded crashes, and on-roaddriving). Cumulative meta-analysis techniques were used to examine thepredictive utility of the test, to determine whether the effect size was stable acrossstudies, and to assess whether a sufficient number of studies have been conductedto conclude that the test is an effective predictor of driving competence. Resultsshowed that the study samples could have been drawn from the same population.The weighted mean effect size across all studies revealed a large effect, Cohen’sd=0.945, with poorer UFOV® test performance associated with negative drivingoutcomes. This relationship was robust across multiple indices of drivingperformance and several research laboratories. A concrete measure of sufficiencyrevealed that an additional 513 studies averaging a null result must be conductedto bring the p-value for the cumulative effect size to greater than .05. Thisconvergence of evidence across different points in time and different researchteams confirms the importance of the UFOV® assessment as a valid and reliableindex of driving performance and safety. Corroborating this finding, a recent largefield study in Maryland has further established the UFOV® test as a usefulscreening instrument to identify at-risk older drivers. Taken together, thesefindings could have far-reaching implications for public policy

Longitudinal Assessment of Older Drivers in a DMV Setting

A brief battery of functional assessments designed to detect crash riskamong older drivers was developed and evaluated initially in 1999 in Marylandmotor vehicle licensing sites following the routine vision screening exam. Thisbattery contained a number of cognitive tests (e.g., UFOV® subtest 2, the closuresubtest of the Motor Free Visual Perception Test (MVPT), Trails A and B, cuedrecall, delayed recall), and several physical measures (e.g., Rapid Pace Walk,Head and Neck Rotation, Foot Tap, Arm Reach). Older adults (N=4,173; meanage = 69 years) were approached by the staff after license renewal and asked tohelp evaluate the brief battery. Of the 4,173 older adults approached at the fieldsites, 2,114 individuals 55-96 years of age participated. Subsequently, the originalsample of 2,114 participants was invited to come in once again, during their fiveyearlicense renewal cycle, and the functional tests were administered once again.To date, 939 individuals have completed the second screening evaluation. Anexamination of the crash data from the interval between assessments for theseindividuals indicates that the same cognitive measures are predictive of at-faultcrashes. Furthermore, approximately 10% of those passing the assessment in 1999are now failing the assessment in 2004. Performance-based cognitive measuresare predictive of future at-fault motor vehicle collisions among older adults.Cognitive performance, in particular, is a salient predictor of subsequent crashinvolvement among older adults. High-risk older drivers can be identified throughbrief, performance-based measures administered in a DMV setting

Kentucky Labor Supply and Demand Surveys

Excerpt from the executive summary: The Center for Business and Economic Research at the University of Kentucky (CBER), along with its partners, the Survey Research Center at the University of Kentucky (UK-SRC), the Survey Research Center in the Urban Studies Institute at the University of Louisville (UL-SRC), and the Department of Economics at the University of Louisville, is pleased to present this final report on the findings of the Kentucky labor supply and demand surveys sponsored by the Kentucky Cabinet for Workforce Development. The two universities have put together a consortium including some of the best scholars in the region in the areas of labor economics, local economic development, and survey design and administration

Multiple List Learning in Adults with Autism Spectrum Disorder: Parallels with Frontal Lobe Damage or Further Evidence of Diminished Relational Processing?

To test the effects of providing relational cues at encoding and/or retrieval on multi-trial, multi-list free recall in adults with high-functioning autism spectrum disorder (ASD), 16 adults with ASD and 16 matched typical adults learned a first followed by a second categorised list of 24 words. Category labels were provided at encoding, retrieval, both or not at all. Both groups showed enhanced recall when labels were available during encoding or throughout the task. ASD individuals showed reduced recall of the second list and reduced clustering. Clustering and recall were correlated in both groups, which also showed similar levels of subjective organisation. The findings are discussed in relation to theories of frontal and medial temporal lobe contributions to memory in ASD