828 research outputs found

    Alternative Modes for Teaching Mathematical Problem Solving: An Overview

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    Various modes are proffered as alternatives for teaching mathematical problem solving. Each mode is described briefly, along with general purposes, advantages and disadvantages. Combinations of modes are suggested; general issues identified; recommendations offered; and feedback from teachers summarized

    Experimental nuclear cross sections for spacecraft shield analysis

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    Experiments have been performed to validate and to supplement the intranuclear cascade model as a method for estimating cross sections of importance to spacecraft shield design. The experimental situation is inconclusive particularly for neutron-producing reactions, but is relatively sound for reaction cross sections and for proton spectra at several hundred MeV at medium forward angles. Secondary photon contributions are imprecisely known

    Rapid computation of specific energy losses for energetic charged particles

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    Rapid computation of specific energy losses for energetic charged particle

    Nuclear reaction cross sections for spacecraft shield design

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    Nuclear reaction cross section data for spacecraft shield design, and for determining radiation dose effect on astronaut

    Where did Words Come from? A Linking Theory of Sound Symbolism and Natural Language Evolution

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    Where did words come from? The traditional view is that the relation between the sound of a word and its meaning is arbitrary. An alternative hypothesis, known as sound symbolism, holds that form-meaning correspondence is systematic. Numerous examples of sound symbolism exist across natural language phyla. Moreover, cross-linguistic similarities suggest that sound symbolism represents a language universal. For example, many unrelated languages affix an "ee" sound to words in order to emphasize size distinctions or express affection (e.g., look at the teeny weeny baby); other such phonetic universals are evident for object mass, color, brightness, and aggression. We hypothesize that sound symbolism reflects sensitivity to an ecological law (i.e., Hooke's Law) governing an inverse relation between object mass and acoustic resonance. In two experiments healthy adults showed high agreement in matching pure tones to color swatches and nonwords to novel objects as linear functions of frequency and luminance. These results support a degree of non-arbitrariness in integrating visual and auditory information. We discuss implications for sound symbolism as a factor underlying language evolution

    Under the Fluorescent Sun

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    Establishing an energy scale for pulse-height distributions from gamma-ray spectrometers based on inorganic scintillators

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    Energy scale for pulse height distributions from gamma ray spectrometers based on inorganic scintillator

    Differential cross sections at forward angles for hydrogen and helium particles from 62 MeV protons incident on Ni-60

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    Tabulated differential cross sections are presented for the production, at angles of 15, 20, 25, and 40 deg, of proton, deuteron, triton, helium-3, and alpha particles from Ni-60 bombarded by 62-MeV protons. Continuum cross sections are listed in about 1-MeV bins for energies above lower cutoffs which range from 4 to 15 MeV for the different types of exit particles. Only the integral cross section is known for a considerable energy range within each spectrum. The proton, deuteron, and alpha particle cross sections are the same in the continuum range region above the evaporation peak as those cross sections previously observed for Fe-54 and Fe-56, but the corresponding yield of tritons is higher from Ni-60 and Fe-56 than from Fe-54

    Tabulated cross sections for hydrogen and helium particles produced by 61-MeV protons on Fe56

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    Tabulated cross sections for hydrogen and helium particles produced by 61 MeV on iron 5

    Methodological challenges and solutions in auditory functional magnetic resonance imaging

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    Functional magnetic resonance imaging (fMRI) studies involve substantial acoustic noise. This review covers the difficulties posed by such noise for auditory neuroscience, as well as a number of possible solutions that have emerged. Acoustic noise can affect the processing of auditory stimuli by making them inaudible or unintelligible, and can result in reduced sensitivity to auditory activation in auditory cortex. Equally importantly, acoustic noise may also lead to increased listening effort, meaning that even when auditory stimuli are perceived, neural processing may differ from when the same stimuli are presented in quiet. These and other challenges have motivated a number of approaches for collecting auditory fMRI data. Although using a continuous echoplanar imaging (EPI) sequence provides high quality imaging data, these data may also be contaminated by background acoustic noise. Traditional sparse imaging has the advantage of avoiding acoustic noise during stimulus presentation, but at a cost of reduced temporal resolution. Recently, three classes of techniques have been developed to circumvent these limitations. The first is Interleaved Silent Steady State (ISSS) imaging, a variation of sparse imaging that involves collecting multiple volumes following a silent period while maintaining steady-state longitudinal magnetization. The second involves active noise control to limit the impact of acoustic scanner noise. Finally, novel MRI sequences that reduce the amount of acoustic noise produced during fMRI make the use of continuous scanning a more practical option. Together these advances provide unprecedented opportunities for researchers to collect high-quality data of hemodynamic responses to auditory stimuli using fMRI
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