719 research outputs found
Neural nets for aligning optical components in harsh environments: Beam smoothing spatial filter as an example
The goal is to develop an approach to automating the alignment and adjustment of optical measurement, visualization, inspection, and control systems. Classical controls, expert systems, and neural networks are three approaches to automating the alignment of an optical system. Neural networks were chosen for this project and the judgements that led to this decision are presented. Neural networks were used to automate the alignment of the ubiquitous laser-beam-smoothing spatial filter. The results and future plans of the project are presented
Paradoxical Sleep Suppresses Immediate Early Gene Expression in the Rodent Suprachiasmatic Nuclei
Light stimulates neuronal activity with subsequent expression of the protein product of the immediate early gene, c-fos, in the Suprachiasmatic Nuclei (SCN). Non-photic stimuli is also thought to modulate activity within the SCN. Here, we sought to determine the effects intrinsic stimuli, specifically, the states of sleep upon c-fos protein expression in the SCN. In 16 rats, c-fos protein expression was evaluated at a fixed time of 1600 h (subjective night), following 1 h of electroencephalographically defined sleep. During sleep, as the state of paradoxical sleep (PS) increased, c-fos protein expression decreased (r = −0.41, p < 0.033). The PS-associated reduction of c-fos positive cells occurred equally between animals asleep in the light and those asleep in the dark. We propose a model whereby PS duration might function as a homeostatic-entraining mechanism to reduce neuronal activity within the SCN, and thereby modulate circadian rhythms during sleep
WILDLIFE DAMAGE TO CROPS: PERCEPTIONS OF AGRICULTURAL AND WILDLIFE PROFESSIONALS IN 1957 AND 1987
We surveyed state wildlife agencies, state agricultural departments, Wildlife Extension Specialists, U.S.D.A. Animal Damage Control agents, and state Farm Bureau officials to develop a national perspective of wildlife damage to agricultural crops in the U.S. A broad concensus existed that wildlife damage was a major problem, although groups often differed in their perceptions of the seriousness of specific problems. The complexity of the wildlife damage problem was apparent in that 27 different wildlife species were cited as causing the greatest problem to a state\u27s farmers. Nevertheless, 38-80% of the respondents from every group surveyed stated that deer were their worst problem. Most respondents believed that wildlife damage had increased in the last 30 years. Increasing levels of wildlife damage also were apparent when we compared our findings to those of a similar survey conducted in 1957 (McDowell and Pillsbury 1958). For instance in 1957, 16 states reported that deer were either no problem or only caused localized problems, while in our survey, 15 of these 16 states stated that deer were now causing more damage to crops than any other wildlife species
On the Development of the Artillery Flight Characterization Electronics Rescue Kit
21st AIAA Aerodynamic Decelerator Systems Technology Conference and Seminar,
23 - 26 May 2011, Dublin, IrelandThis paper investigates a prospective avionics suite rescue kit to salvage some of the state-of-the-art
electronics in the data-collecting fuze system employed on an artillery projectile. A single-use data
collection fuze is currently in use by the Army that relays sensor measurements for the purpose of
characterizing the flight of an artillery projectile. The goal of the present study is to develop a
parachute/parafoil-based system to be deployed automatically at apogee, so that the ! Reuse-Fuze"
becomes separated from the body of the artillery shell and safely recovered. The paper presents the
overall design of the Reuse-Fuze system, including the release mechanism, deceleration system, and
impact survivability considerations. The successful design of a recoverable and reusable fuze-shaped
data collection system will allow the Army to conduct repeated artillery testing without increasing the
cost of expensive electronics hardware
Uncertainty Monitoring by Young Children in a Computerized Task
Adult humans show sophisticated metacognitive abilities, including the ability to monitor uncertainty. Unfortunately, most measures of uncertainty monitoring are limited to use with adults due to their general complexity and dependence on explicit verbalization. However, recent research with nonhuman animals has successfully developed measures of uncertainty monitoring that are simple and do not require explicit verbalization. The purpose of this study was to investigate metacognition in young children using uncertainty monitoring tests developed for nonhumans. Children judged whether stimuli were more pink or blue—stimuli nearest the pink-blue midpoint were the most uncertain and the most difficult to classify. Children also had an option to acknowledge difficulty and gain the necessary information for correct classification. As predicted, children most often asked for help on the most difficult stimuli. This result confirms that some metacognitive abilities appear early in cognitive development. The tasks of animal metacognition research clearly have substantial utility for exploring the early developmental roots of human metacognition
Monkeys (Macaca mulatta and Cebus apella) and Human Adults and Children (Homo sapiens) Enumerate and Compare Subsets of Moving Stimuli Based on Numerosity
Two monkey species (Macaca mulatta and Cebus apella) and human children and adults judged the numerousness of two subsets of moving stimuli on a computer screen. Two sets of colored dots that varied in number and size were intermixed in an array in which all dots moved in random directions and speeds. Participants had to indicate which dot color was more numerous within the array. All species performed at high and comparable levels, including on trials in which the subset with the larger number of items had a smaller total area of coloration. This indicated a similarity across species to use the number of items in the subsets, and not dimensions such as area or volume, to guide decision making. Discrimination performance was constrained by the ratio between the subsets, consistent with other reports of numerousness judgments of stationary stimuli. These results indicate a similarity in numerical estimation ability for moving stimuli across primate species, and this capacity may be necessary for naturally occurring experiences in which moving stimuli must be summed
Biotic and Abiotic Effects on Endoparasites Infecting \u3ci\u3eDipodomys\u3c/i\u3e and \u3ci\u3ePerognathus\u3c/i\u3e Species
Between 1989 and 1998, 3,504 rodents of the genera Dipodomys and Perognathus were collected from 4 permanent collecting sites on the University of New Mexico’s Long Term Ecological Research station, located on the Sevilleta National Wildlife Refuge (SNWR), Socorro County, New Mexico. All animals were killed and examined for endoparasites (acanthocephalans, cestodes, coccidia, and nematodes). The present report focuses on 3 endoparasite groups, cestodes, coccidia, and nematodes. Specific analyses address how prevalence changes were related to abiotic factors such as habitat, season, or precipitation, and how prevalence of each parasite species in each host species differed in relation to host age, host sex, host reproductive status, host body mass, host density, parasite-parasite interactions, and host specificity. A logistic regression was used to determine which host characters and which abiotic factors are correlated with a parasite infection. Significant variables for at least half of the parasites include season, site, and winter precipitation. However, no parasite prevalences were correlated, and significant variables were not identical between parasites, indicating that each parasite species varied independently and that no generalizations can be drawn. The parasite prevalences in these rodents on the SNWR vary in independent and complex ways
Monkeys (Macaca Mulatta and Cebus Apella) and Human Adults and Children (Homo Sapiens) Compare Subsets of Moving Stimuli Based on Numerosity
Two monkey species (Macaca mulatta and Cebus apella) and human children and adults judged the numerousness of two subsets of moving stimuli on a computer screen. Two sets of colored dots that varied in number and size were intermixed in an array in which all dots moved in random directions and speeds. Participants had to indicate which dot color was more numerous within the array. All species performed at high and comparable levels, including on trials in which the subset with the larger number of items had a smaller total area of coloration. This indicated a similarity across species to use the number of items in the subsets, and not dimensions such as area or volume, to guide decision making. Discrimination performance was constrained by the ratio between the subsets, consistent with other reports of numerousness judgments of stationary stimuli. These results indicate a similarity in numerical estimation ability for moving stimuli across primate species, and this capacity may be necessary for naturally occurring experiences in which moving stimuli must be summed
Neural-network-directed alignment of optical systems using the laser-beam spatial filter as an example
This report describes an effort at NASA Lewis Research Center to use artificial neural networks to automate the alignment and control of optical measurement systems. Specifically, it addresses the use of commercially available neural network software and hardware to direct alignments of the common laser-beam-smoothing spatial filter. The report presents a general approach for designing alignment records and combining these into training sets to teach optical alignment functions to neural networks and discusses the use of these training sets to train several types of neural networks. Neural network configurations used include the adaptive resonance network, the back-propagation-trained network, and the counter-propagation network. This work shows that neural networks can be used to produce robust sequencers. These sequencers can learn by example to execute the step-by-step procedures of optical alignment and also can learn adaptively to correct for environmentally induced misalignment. The long-range objective is to use neural networks to automate the alignment and operation of optical measurement systems in remote, harsh, or dangerous aerospace environments. This work also shows that when neural networks are trained by a human operator, training sets should be recorded, training should be executed, and testing should be done in a manner that does not depend on intellectual judgments of the human operator
In planta expression of A. cellulolyticus Cel5A endocellulase reduces cell wall recalcitrance in tobacco and maize
The glycoside hydrolase family 5 endocellulase, E1 (Cel5A), from Acidothermus cellulolyticus was transformed into both Nicotiana tabacum and Zea mays with expression targeted to the cell wall under a constitutive promoter. Here we explore the possibility that in planta expression of endocellulases will allow these enzymes to access their substrates during cell wall construction, rendering cellulose more amenable to pretreatment and enzyme digestion. Tobacco and maize plants were healthy and developed normally compared with the wild type (WT). After thermochemical pretreatment and enzyme digestion, transformed plants were clearly more digestible than WT, requiring lower pretreatment severity to achieve comparable conversion levels. Furthermore, the decreased recalcitrance was not due to post-pretreatment residual E1 activity and could not be reproduced by the addition of exogenous E1 to the biomass prior to pretreatment, indicating that the expression of E1 during cell wall construction altered the inherent recalcitrance of the cell wall
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