scholarly journals The impact of error frequency on errorless and errorful learning of object locations using a novel paradigm

Memory ◽  
2019 ◽  
Vol 27 (10) ◽  
pp. 1371-1380 ◽  
Author(s):  
Inge Scheper ◽  
Ellen R. A. de Bruijn ◽  
Dirk Bertens ◽  
Roy P. C. Kessels ◽  
Inti A. Brazil
Keyword(s):  
Error Frequency ◽  
Object Locations ◽  
The Impact

Study of MRI Susceptibility Artifacts for Nanomedical Applications

2010 ◽  
Vol 1 (4) ◽  
Author(s):  
Tim Wortmann ◽  
Christian Dahmen ◽  
Sergej Fatikow
Keyword(s):  
Scaling Laws ◽  
Position Control ◽  
Superparamagnetic Nanoparticles ◽  
Susceptibility Artifacts ◽  
Imaging Parameters ◽  
Object Locations ◽  
Gradient Fields ◽  
Mri Scans ◽  
3D Scans ◽  
The Impact

This article deals with the exploitation of magnetic susceptibility artifacts in magnetic resonance imaging (MRI) for the recognition of metallic delivery capsules. The targeted application is a closed-loop position control of magnetic objects implemented using the components of a clinical MRI scanner. Actuation can be performed by switching the magnetic gradient fields, whereas object locations are detected by an analysis of the MRI scans. A comprehensive investigation of susceptibility artifacts with a total number of 108 experimental setups has been performed in order to study scaling laws and the impact of object properties and imaging parameters. In addition to solid metal objects, a suspension of superparamagnetic nanoparticles has been examined. All 3D scans have been segmented automatically for artifact quantification and location determination. Analysis showed a characteristic shape for all three base types of sequences, which is invariant to the magnetic object shape and material. Imaging parameters such as echo time and flip angle have a moderate impact on the artifact volume but do not modify the characteristic artifact shape. The nanoparticle agglomerates produce imaging artifacts similar to the solid samples. Based on the results, a two-stage recognition/tracking procedure is proposed.

Tactile object localization by anticipatory whisker motion

2015 ◽  
Vol 113 (2) ◽  
pp. 620-632 ◽  
Author(s):  
Jakob Voigts ◽  
David H. Herman ◽  
Tansu Celikel
Keyword(s):  
High Speed ◽  
Sensory Input ◽  
Motor Pattern ◽  
Object Localization ◽  
Error Signal ◽  
High Speed Imaging ◽  
Object Locations ◽  
Other Information ◽  
Actual Environment ◽  
The Impact

Rodents use rhythmic protractions of their whiskers to locate objects in space. The amplitude of these protractions is reduced when whiskers contact objects, leading to a tendency of whiskers to only lightly touch the environment. While the impact of this process on the sensory input has been studied, little is known about how sensory input causes this change in the motor pattern. Here, using high-speed imaging of whisking in mice, we simultaneously measured whisker contacts and the resulting whisking motion. We found that mice precisely target their whisker protractions to the distance at which they expect objects. This modulation does not depend on the current sensory input and remains stable for at least one whisking cycle when there is no object contact or when the object position is changed. As a result, the timing and other information carried by whisker contacts encodes how well each protraction was matched to the object, functioning as an error signal. Whisker contacts can thus encode a mismatch between expected object locations and the actual environment.

Method Bias and Concurrent Verbal Protocol in Software Usability Testing

1992 ◽  
Vol 36 (16) ◽  
pp. 1220-1224 ◽  
Author(s):  
Richard B. Wright ◽  
Sharonlyn A. Converse
Keyword(s):  
Mental Workload ◽  
Usability Testing ◽  
Potential Method ◽  
Ease Of Use ◽  
Software Usability ◽  
Usability Tests ◽  
Error Frequency ◽  
Task Time ◽  
Method Bias ◽  
The Impact

Concurrent verbal protocols are gaining wide acceptance in software usability testing. In this study, the impact concurrent verbalization has on task performance during a software usability test was investigated. Subjects randomly assigned to two levels of verbalization were asked to complete four tasks of varying difficulty using a disk utility package. Subjects in the verbalization condition were asked to provide an explanation for each step taken to complete a task. Subjects in the control condition were allowed to complete each task silently. Dependent variables were task time, error frequency, and responses to subjective measures of mental workload and ease-of-use. Subjects in the verbalization condition committed fewer errors and consumed less task time than subjects in the silent condition. Further, the mean difference in error frequency and task time between conditions increased with task difficulty. These results were extremely important in revealing a potential method bias in usability tests.

Formation of Lunar Craters and Bright Rays as a Result of Meteorite Impacts

1962 ◽  
Vol 14 ◽  
pp. 415-418
Author(s):  
K. P. Stanyukovich ◽  
V. A. Bronshten
Keyword(s):  
Explosive Charge ◽  
The Moon ◽  
Meteorite Impacts ◽  
The Earth ◽  
Lunar Craters ◽  
The Impact

The phenomena accompanying the impact of large meteorites on the surface of the Moon or of the Earth can be examined on the basis of the theory of explosive phenomena if we assume that, instead of an exploding meteorite moving inside the rock, we have an explosive charge (equivalent in energy), situated at a certain distance under the surface.

The Geosciences Applied to Lunar Exploration

1962 ◽  
Vol 14 ◽  
pp. 169-257 ◽  
Author(s):  
J. Green
Keyword(s):  
Lunar Surface ◽  
Probable Mechanism ◽  
Point Of View ◽  
Lunar Exploration ◽  
Geological Model ◽  
Apply Geophysics ◽  
Surface Features ◽  
The Impact

The term geo-sciences has been used here to include the disciplines geology, geophysics and geochemistry. However, in order to apply geophysics and geochemistry effectively one must begin with a geological model. Therefore, the science of geology should be used as the basis for lunar exploration. From an astronomical point of view, a lunar terrain heavily impacted with meteors appears the more reasonable; although from a geological standpoint, volcanism seems the more probable mechanism. A surface liberally marked with volcanic features has been advocated by such geologists as Bülow, Dana, Suess, von Wolff, Shaler, Spurr, and Kuno. In this paper, both the impact and volcanic hypotheses are considered in the application of the geo-sciences to manned lunar exploration. However, more emphasis is placed on the volcanic, or more correctly the defluidization, hypothesis to account for lunar surface features.

Asteroid and Comet Impact Speeds upon Mars: Significance for Panspermia and the Supply of Organics

1997 ◽  
Vol 161 ◽  
pp. 197-201 ◽  
Author(s):  
Duncan Steel
Keyword(s):  
Probability Distributions ◽  
Regions Of Interest ◽  
Significant Fraction ◽  
Organic Chemicals ◽  
Impact Speed ◽  
The Mean ◽  
The Impact

AbstractWhilst lithopanspermia depends upon massive impacts occurring at a speed above some limit, the intact delivery of organic chemicals or other volatiles to a planet requires the impact speed to be below some other limit such that a significant fraction of that material escapes destruction. Thus the two opposite ends of the impact speed distributions are the regions of interest in the bioastronomical context, whereas much modelling work on impacts delivers, or makes use of, only the mean speed. Here the probability distributions of impact speeds upon Mars are calculated for (i) the orbital distribution of known asteroids; and (ii) the expected distribution of near-parabolic cometary orbits. It is found that cometary impacts are far more likely to eject rocks from Mars (over 99 percent of the cometary impacts are at speeds above 20 km/sec, but at most 5 percent of the asteroidal impacts); paradoxically, the objects impacting at speeds low enough to make organic/volatile survival possible (the asteroids) are those which are depleted in such species.

Organic Syntheses During the Impact of a Comet with a Gaseous Planet

1997 ◽  
Vol 161 ◽  
pp. 189-195
Author(s):  
Cesare Guaita ◽  
Roberto Crippa ◽  
Federico Manzini
Keyword(s):  
Polymeric Material ◽  
Molecular Form ◽  
Parent Compound ◽  
Blue Filter ◽  
Organic Syntheses ◽  
The Impact

AbstractA large amount of CO has been detected above many SL9/Jupiter impacts. This gas was never detected before the collision. So, in our opinion, CO was released from a parent compound during the collision. We identify this compound as POM (polyoxymethylene), a formaldehyde (HCHO) polymer that, when suddenly heated, reformes monomeric HCHO. At temperatures higher than 1200°K HCHO cannot exist in molecular form and the most probable result of its decomposition is the formation of CO. At lower temperatures, HCHO can react with NH3 and/or HCN to form high UV-absorbing polymeric material. In our opinion, this kind of material has also to be taken in to account to explain the complex evolution of some SL9 impacts that we observed in CCD images taken with a blue filter.

Hydrogen Cyanide Polymers from the Impact of Comet P/Shoemaker-Levy 9 on Jupiter

1997 ◽  
Vol 161 ◽  
pp. 179-187
Author(s):  
Clifford N. Matthews ◽  
Rose A. Pesce-Rodriguez ◽  
Shirley A. Liebman
Keyword(s):  
Amino Acids ◽  
Solar System ◽  
Hydrogen Cyanide ◽  
Nitrogen Heterocycles ◽  
Laboratory Studies ◽  
Heterogeneous Solids ◽  
The Many ◽  
Comet Halley ◽  
The Impact ◽  
By Products

AbstractHydrogen cyanide polymers – heterogeneous solids ranging in color from yellow to orange to brown to black – may be among the organic macromolecules most readily formed within the Solar System. The non-volatile black crust of comet Halley, for example, as well as the extensive orangebrown streaks in the atmosphere of Jupiter, might consist largely of such polymers synthesized from HCN formed by photolysis of methane and ammonia, the color observed depending on the concentration of HCN involved. Laboratory studies of these ubiquitous compounds point to the presence of polyamidine structures synthesized directly from hydrogen cyanide. These would be converted by water to polypeptides which can be further hydrolyzed to α-amino acids. Black polymers and multimers with conjugated ladder structures derived from HCN could also be formed and might well be the source of the many nitrogen heterocycles, adenine included, observed after pyrolysis. The dark brown color arising from the impacts of comet P/Shoemaker-Levy 9 on Jupiter might therefore be mainly caused by the presence of HCN polymers, whether originally present, deposited by the impactor or synthesized directly from HCN. Spectroscopic detection of these predicted macromolecules and their hydrolytic and pyrolytic by-products would strengthen significantly the hypothesis that cyanide polymerization is a preferred pathway for prebiotic and extraterrestrial chemistry.

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