Clinical assessment of brain function relies heavily on indirect behavior-based tests. Unfortunately, behavior-based assessments are subjective and therefore susceptible to several confounding factors. Event-related brain potentials (ERPs), derived from electroencephalography (EEG), are often used to provide objective, physiological measures of brain function. Historically, ERPs have been characterized extensively within research settings, with limited but growing clinical applications. Over the past 20 years, we have developed clinical ERP applications for the evaluation of functional status following serious injury and/or disease. This work has identified an important gap: the need for a clinically accessible framework to evaluate ERP measures. Crucially, this enables baseline measures before brain dysfunction occurs, and might enable the routine collection of brain function metrics in the future much like blood pressure measures today. Here, we propose such a framework for extracting specific ERPs as potential “brain vital signs.” This framework enabled the translation/transformation of complex ERP data into accessible metrics of brain function for wider clinical utilization. To formalize the framework, three essential ERPs were selected as initial indicators: (1) the auditory N100 (Auditory sensation); (2) the auditory oddball P300 (Basic attention); and (3) the auditory speech processing N400 (Cognitive processing). First step validation was conducted on healthy younger and older adults (age range: 22–82 years). Results confirmed specific ERPs at the individual level (86.81–98.96%), verified predictable age-related differences (P300 latency delays in older adults, p < 0.05), and demonstrated successful linear transformation into the proposed brain vital sign (BVS) framework (basic attention latency sub-component of BVS framework reflects delays in older adults, p < 0.05). The findings represent an initial critical step in developing, extracting, and characterizing ERPs as vital signs, critical for subsequent evaluation of dysfunction in conditions like concussion and/or dementia.
This article describes and evaluates Project C.A.R.E., a substance abuse prevention program for three cohorts of at‐risk fourth graders and their families. Project C.A.R.E. worked intensively with students and their families to increase resiliency factors and decrease risk factors through school, family, and extracurricular activities. The research design was experimental. Project objectives were to decrease substance use, negative behaviors, intent to use substances, school suspensions, and absences; and to increase alternative activities, family communication, academic grades, and consistency of family behavior control and rules. A few positive program effects were found. At posttest, more control students' grades needed improvement, and more program students participated in community activities. Several variables showed differential change over time which favored the program group. Compared to control students, program students increased participation in alternative activities from pretest to posttest and did not increase their school suspensions as much. At the one year follow‐up, control students were more willing to use substances than were program students. The program appeared to have the most impact with the third cohort of students and with Black students. Program students with low participation generally had the worst outcomes, often worse than the control students. It was suggested that more research should be done examining differential effectiveness, especially racial and program participation differences, as they could have a profound impact on program development and implementation. © 1997 John Wiley & Sons, Inc.
Power cable reflectivities have been measured for both dry and wet conditions using a 10.6 pm coherent CO2 laser radar. Measurements were made at a range of 620 meters using two types of cable; 1-in.-diameter Grosbeak and 3/8-in. Grouse, at 600 aspect angles relative to the normal in increments of 10°. The cables were both artificially sprayed, in an effort to simulate realistic rainfall rates, as well as being exposed to light rain. Results show that the drop in reflectivity of wet cables compared to dry cables is a function of aspect angle with a mean drop for the Grosbeak and Grouse cables of -5 dB and -1.3 dB, respectively. Measurements of the drying rates of the cables showed a return to the dry state reflectivity in approximately 100 sec after being liberally doused.The system sensitivity required of a coherent optical sensor to achieve optimum detection and false alarm rates results from a complex interplay of system parameters as expressed through the power signal-to-noise ratio (SNR), that is: O-8194-0506-X/91/$4.OO SPIE Vol. 1416 Laser Radar VI (1991) / 221 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/26/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx
This article reports on an innovative MBA elective consulting course that attempts to address how to better prepare inexperienced MBA students for a competitive job market. This article is a best practice paper designed to provide insights and encouragement to educators.
We have developed an approach to multiple-access lasercom that adopts the commercial paradigm of sharing the most expensive terminal resources among all users. Space-time division multiple access (STDMA), analogous to an optical space-time switch, hops the transmit beam and receive direction among multiple users and exchanges data while the beam dwells on a user. A key enabler of STDMA is electronic beam steering using liquid crystal optical phased arrays, which provides fast, precise, and agile beam re-pointing. We have built the first optical STDMA terminal, combining beam hopping between remote terminals with coherent combining of both transmit and receive apertures, which is an effective means for increasing antenna gain in systems for which large aperture components are impractical. Coherent beam combining provided the expected increase in antenna gain, and the terminal was found to re-point the beam among users quickly and precisely enough to suffer only minor throughput degradation. Communications test were performed using 10 Gb/s Ethernet for a single-aperture configuration. Performance is presented as a function of angle scan speed and STDMA dwell time per remote terminal. The results suggest that STDMA is a viable technology for supporting multiple-access space-based laser communication.
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