1,567 research outputs found
Wind tunnel model and method
The design and development of a wind tunnel model equipped with pressure measuring devices are discussed. The pressure measuring orifices are integrally constructed in the wind tunnel model and do not contribute to distortions of the aerodynamic surface. The construction of a typical model is described and a drawing of the device is included
Optimal utility and probability functions for agents with finite computational precision
When making economic choices, such as those between goods or gambles, humans act as if their internal representation of the value and probability of a prospect is distorted away from its true value. These distortions give rise to decisions which apparently fail to maximize reward, and preferences that reverse without reason. Why would humans have evolved to encode value and probability in a distorted fashion, in the face of selective pressure for reward-maximizing choices? Here, we show that under the simple assumption that humans make decisions with finite computational precisionââin other words, that decisions are irreducibly corrupted by noiseââthe distortions of value and probability displayed by humans are approximately optimal in that they maximize reward and minimize uncertainty. In two empirical studies, we manipulate factors that change the reward-maximizing form of distortion, and find that in each case, humans adapt optimally to the manipulation. This work suggests an answer to the longstanding question of why humans make âirrationalâ economic choices
Orienting Attention Based on Long-Term Memory Improves Perceptual Discriminations
The role of attentional orienting in daily life is to selectively deploy both behavioural and neural resources towards events, based on continually changing task goals and expectations, in order to optimize performance. In the following experiment, we show that attentional orienting is influenced by long-term memories in a perceptual discrimination task. In the learning phase, participants were trained on 120 ecologically valid natural scenes, of which 80 contained a target. Their task was to locate the target (a small key) on the screen by clicking on it with the mouse. One or two days later, participants completed a cued perceptual discrimination task. The same scenes that were studied before, but without any targets, were presented as cues (50 ms duration), followed, after a delay (450ms), by the scene again with or without the target (200ms). Participants discriminated covertly whether the key was present or absent from the second scene. There were three conditions: valid (key in learning and discrimination task was in same location), invalid (key in learning and discrimination task were in different location) and neutral (there was no key in learning phase). Behavioural results indicated that memory-guided attention benefits both the sensitivity (d’) and speed of target identification within natural scenes. A replication of the study is being carried out with event-related potentials to chart the neural modulations that accompany the perceptual enhancements observed behaviourally
Determination of the Phonon Spectrum of Polyethylene by Neutron Scattering
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70180/2/JCPSA6-43-3-1079-1.pd
Effectiveness of computer-based auditory training in improving the perception of noise-vocoded speech
Five experiments were designed to evaluate the effectiveness of âhigh-variabilityâ lexical training in improving the ability of normal-hearing subjects to perceive noise-vocoded speech that had been spectrally shifted to simulate tonotopic misalignment. Two approaches to training were implemented. One training approach required subjects to recognize isolated words, while the other training approach required subjects to recognize words in sentences. Both approaches to training improved the ability to identify words in sentences. Improvements following a single session (lasting 1â2 h) of auditory training ranged between 7 and 12 %pts and were significantly larger than improvements following a visual control task that was matched with the auditory training task in terms of the response demands. An additional three sessions of word- and sentence-based training led to further improvements, with the average overall improvement ranging from 13 to 18 %pts. When a tonotopic misalignment of 3 mm rather than 6 mm was simulated, training with several talkers led to greater generalization to new talkers than training with a single talker. The results confirm that computer-based lexical training can help overcome the effects of spectral distortions in speech, and they suggest that training materials are most effective when several talkers are included
Addendum: OneâSpeed Neutron Transport in Two Adjacent HalfâSpaces
The interface current for the problem of two halfâspaces with a constant source in one halfâspace is obtained in closed form.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70010/2/JMAPAQ-5-12-1804-1.pd
Global Transcriptional Response of the Alkalitolerant Cyanobacterium Synechocystis sp. Strain PCC 6803 to pH 10.
Many cyanobacterial strains are able to grow at a pH range from neutral to pH 10 or 11. Such alkaline conditions favor cyanobacterial growth (e.g., bloom formation), and cyanobacteria must have developed strategies to adjust to changes in CO2 concentration and ion availability. Synechocystis sp. strain PCC 6803 exhibits similar photoautotrophic growth characteristics at pH 10 and pH 7.5, and we examined global gene expression following transfer from pH 7.5 to pH 10 to determine cellular adaptations at an elevated pH. The strategies used to develop homeostasis at alkaline pH had elements similar to those of many bacteria, as well as components unique to phototrophic microbes. Some of the response mechanisms previously identified in other bacteria included upregulation of Na+/H+ antiporters, deaminases, and ATP synthase. In addition, upregulated genes encoded transporters with the potential to contribute to osmotic, pH, and ion homeostasis (e.g., a water channel protein, a large-conductance mechanosensitive channel, a putative anion efflux transporter, a hexose/proton symporter, and ABC transporters of unidentified substrates). Transcriptional changes specific to photosynthetic microbes involved NADH dehydrogenases and CO2 fixation. The pH transition altered the CO2/HCO3â ratio within the cell, and the upregulation of three inducible bicarbonate transporters (BCT1, SbtA, and NDH-1S) likely reflected a response to this perturbed ratio. Consistent with this was increased transcript abundance of genes encoding carboxysome structural proteins and carbonic anhydrase. Interestingly, the transition to pH 10 resulted in increased abundance of transcripts of photosystem II genes encoding extrinsic and low-molecular-weight polypeptides, although there was little change in photosystem I gene transcripts
METHODS OF CALCULATION OF MSW STRUCTURES
The paper reviews the existing methods for the solution of structures supporting propaga-
tion of magnetostatic waves. Due to the fact that these are mostly multilayered structures
the mostly used numerical techniques for their calculation are the method of the surface
permeability, finite element method and the boundary element method. Because each
of them is more or less suitable in special cases, the advantages of each are discussed
and pointed out in the paper. The general magnetic anisotropy formulation has been
introduced into boundary element method
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