Papers by Ray Edward Johnson
New Directions for Community Colleges, 1976
On the neural generators of the P300 component of the event‐related potential
Psychophysiology, 2007
The triarchic model of P300 amplitude (Johnson, 1986, 1988a) postulated that the overall amplitud... more The triarchic model of P300 amplitude (Johnson, 1986, 1988a) postulated that the overall amplitude of the P300 recorded at any given electrode site represented the summation of activity from different neural generators, each related to the processing of a different type of information. However, neither of these original accounts provided an explicit description of the methods required to establish experimentally the presence of multiple neural sources. This paper reviews the triarchic amplitude model, the subsequently obtained data that support the postulated presence of multiple generators underlying the P300, and the methods used to demonstrate the presence of these multiple sources. These methods are straightforward because it is only necessary to show that the portions of P300 amplitude associated with different experimental variables have different scalp distributions. The implications of the multiple‐generator basis of P300 on such factors as component definition, neural sourc...
Portable waterslide and associated method
Device for securing a lid to a pot
Continuous Seismic Wave Communications Experiments at 80 HZ in Diverse Terrains
Abstract : Seismic communications experiments in various terrains employing 80-Hz resonant, 200-w... more Abstract : Seismic communications experiments in various terrains employing 80-Hz resonant, 200-watt seismic transducers as transmitters and 10-watt seismic transducers as receivers are described. Received 80-Hz CW and pulsed CW signal levels, noise levels, signal propagation characteristics, and related communications ranges are given. (Author)
Ray E. Johnson Collection
* Make instruments to develop plan of action with practical targets and budget for the health ins... more * Make instruments to develop plan of action with practical targets and budget for the health institutions * Develop educational materials and training modules * Organize training at District and Chiefdom levels for healthcare workers and the community on the risk associated with healthcare waste and safe management practices, with priority for waste-handlers; * Make available the materials to facilitate medical waste management. * Ensure that all healthcare establishments segregate their waste into harmful and non-harmful categories; * Ensure that all healthcare establishments implement safe handling, storage, transportation, treatment and disposal options; * Include healthcare waste management and prevention of Nosocomial infection into the training curricula of Nurses, Public Health Inspectors, Community Health Officers and Doctors; * Ensure routine monitoring of impact through process indicators. Key partners in the implementation of this plan include but not limited to: Ministries of Health and Land, Housing, and the Environment, non-governmental organizations, and waste producers. The target groups are health workers, medical waste handlers, scavengers, municipal waste handlers, managers of healthcare institutions and the general public. The EHD of MOHS has the statutory responsibility for the safe management of waste (including medical) nationwide. Presently, medical wastes are mixed with municipal waste and disposed of indiscriminately. The existing system of municipal waste collection (public skips and skip trucks) in Freetown has been appraised (Freetown Waste Management Study, June1995) as economical. It should be improved and elaborated to ensure the safe management of healthcare waste and replicated in the Districts. A combination of both sanitary landfill and incineration is considered for the comprehensive waste (municipal and healthcare) treatment and or final disposal option for the Sierra Leone situation. New land will be acquired for purposes of District landfill sites development; hence involuntary resettlement of relocated socioeconomic activities (farming, societal bushes etc) is very possible. Consequently compensation will be inevitable. There is no national policy on involuntary resettlement, however, HSRDP is developing one for Sierra Leone, which can be of benefit to this project. The planed project implementation is over a five-year period (2003-2005) and the estimated cost is USD16, 233,000 (Sixteen million, two hundred and thirty-three thousand and five hundred United States Dollars)
Ray Johnson, Jr. Collection
Hammerhead with nail straightening holes
Partnership for the reform of technical, vocational education and training: the South African experience
Cutting blades and assemblies
The intricacies of accumulation: alpine and serpentine systems are assembly workhorses.(Conveyors)
Assembly, Apr 1, 2008
The Neural Basis of Deception and Credibility Assessment
Credibility Assessment, 2014
Abstract Although all credibility assessment measures, whether behavioral, cognitive, or emotiona... more Abstract Although all credibility assessment measures, whether behavioral, cognitive, or emotional, arise from brain activity in the central nervous system, little was known about the neural basis of deception. The chapter describes how research in the new discipline of cognitive neuroscience, which aims to unify psychology and neurobiology, can reveal the neurocognitive basis of a complex function like deception. This research uses powerful new brain-imaging techniques, both electrophysiological and hemodynamic, to observe where and when different brain areas are activated when persons are engaged in deception. Despite the fact that this research only began a little over a decade ago, many new and important insights into how the cognitive and brain processes used during deception are instantiated in the brain have already been obtained. The chapter provides an integrated review of both the basic and applied neurocognitive studies conducted to date.
European Journal of Plant Pathology, 1999
Rupestris stem pitting (RSP) appears to be the most widespread disease of the rugose wood complex... more Rupestris stem pitting (RSP) appears to be the most widespread disease of the rugose wood complex of grapevines. In previous work we showed that rupestris stem pitting associated virus-1 (RSPaV-1), an agent that has similarities in genome structure to apple stem pitting virus is associated with RSP (Meng et al., 1997, 1998). To validate the association of RSPaV-1 with RSP,
Proceedings of the ITI 2009 31st International Conference on Information Technology Interfaces, 2009
The ability to detect dangerous objects (such as improvised explosive devices) from a distance is... more The ability to detect dangerous objects (such as improvised explosive devices) from a distance is important in security and military environments. Standoff imaging can produce images that have been degraded by atmospheric turbulence, movement, blurring and other factors. The number and size of pixels in the imaging sensor can also contribute to image degradation through under-sampling of the image. Establishing processes that enhance degraded or under-sampled infrared images so that objects of interest can be recognised with more certainty is important. Super-resolution image reconstruction and deconvolution methods are explored, as well as performance improvement measures.
Developmental Evidence for Modality‐Dependent P300 Generators: A Normative Study
Psychophysiology, 1989
ABSTRACTThe behavior of the early and late components of the event‐related brain potential (REP) ... more ABSTRACTThe behavior of the early and late components of the event‐related brain potential (REP) elicited by auditory and visual stimuli was studied in 40 normal females between the ages of 7 and 20. The ERPs were collected using two different tasks (i.e., count and reaction time) in an oddball paradigm. Analysis of the early component (i.e., N1, P2, N2) latencies revealed small but significant decreases with age in the visual modality but no change in the auditory modality. Except for the visual N1, early component amplitudes did not change significantly over this age range. The results showed that auditory and visual P300 latencies, but not amplitudes, changed at significantly different rates over this age range. P300 latencies in the auditory modality showed a relatively abrupt change around age 12, after which P300 latencies changed little and were essentially at their adult levels. The latencies of visual P300s showed a much smaller and more steady decrease with age. Thus visua...
Psychophysiology, 1986
ABSTRACTA model of P300 amplitude is proposed that reduces the many hypothetical constructs invok... more ABSTRACTA model of P300 amplitude is proposed that reduces the many hypothetical constructs invoked to explain variations in P300 amplitude to three dimensions: 1) Subjective Probability, 2) Stimulus Meaning, and 3) Information Transmission. Evidence is presented to support the assertion that variables on the subjective probability and stimulus meaning dimensions have independent and additive contributions to overall P300 amplitude. The amplitude contributions of both of these dimensions, however, are modulated by a multiplicative relation with the proportion of transmitted stimulus information. Within each dimension, the fundamental experimental variables and their interrelations are specified. An example is presented to show how, by using an additive factors method, the respective amplitude effects of the probability and stimulus meaning dimensions can be separated. Supporting data are presented to show that the proposed model provides a reasonable and testable framework in which ...
Psychophysiology, 1985
ABSTRACTThe study‐test paradigm was used to investigate memory acquisition processes and the effe... more ABSTRACTThe study‐test paradigm was used to investigate memory acquisition processes and the effects of repetition on long‐term recognition memory. In this procedure, subjects are presented with a list of words (“targets”) to be memorized (Study series). They are later tested for recognition on a word list comprised of the target words mixed randomly with an equal number of new, distractor words (Test series). Both reaction time and the P300 component of the event‐related brain potential were used as measures of processing time. During the Study series, large P300s were elicited despite a word category probability of 1.0. When the words from the Study series were divided on the basis of recognition performance, words that were subsequently recognized elicited P300s with shorter latencies than unrecognized words. P300 amplitude to words in the Study series increased with repetition while maintaining a constant latency. During the Test series, P300 latency and reaction time decreased ...
Neuropsychology, 2005
A multitarget visual cancellation test was administered to patients with Alzheimer's disease (AD)... more A multitarget visual cancellation test was administered to patients with Alzheimer's disease (AD) and age-matched healthy controls (HC). Attentional loads-physical similarity (number of features shared by target and distractors; 3 levels) and density (number of items per page; 3 levels)-were varied systematically. As physical similarity increased, both groups slowed their search, but whereas the HC group maintained accuracy, the AD group increased commission errors and tended to miss more targets. Increased density yielded slower search and more target omissions in the AD group. Commission errors are additional indicators of higher order attentional deficits, especially in early disease. The findings suggest that patients with AD may rely increasingly on physical features of stimuli during a search, leading to inefficient bottom-up processing strategies.
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Papers by Ray Edward Johnson