Two experiments tested the effects of preview sentences and headings on the quality of college students' outlines of informational texts. Experiment 1 found that performance was much better in the preview sentences condition than in a no-signals condition for both printed text and text-to-speech (TTS) audio rendering of the printed text. In contrast, performance in the headings condition was good for the printed text but poor for the auditory presentation because the TTS software failed to communicate nonverbal information carried by the visual headings. Experiment 2 compared outlining performance for five headings conditions during TTS presentation. Using a theoretical framework, "signaling available, relevant, accessible" (SARA) information, to provide an analysis of the information content of headings in the printed text, the manipulation of the headings systematically restored information that was omitted by the TTS application in Experiment 1. The result was that outlining performance improved to levels similar to the visual headings condition of Experiment 1. It is argued that SARA is a useful framework for guiding future development of TTS software for a wide variety of text signaling devices, not just headings.
Two experiments compared three methods of translating printed headings into an auditory format. In both experiments, college students listened to a text with instructions to stop the recording whenever they heard a heading and type the hierarchical level and exact wording of the heading. Listeners were poor at identifying headings and their levels if the headings were not distinguished from the rest of the text. However, listeners were very good at identifying headings if any method of signalling was used to distinguish headings and communicate their hierarchical level. The methods included: (1) tones preceding headings, (2) changes of speaker to indicate headings or (3) verbal labels preceding headings. Although all three signalling methods improved identification of a heading's hierarchical level, the labelling method was the most effective means of communicating hierarchical level. Thus, the study identifies a simple method of effectively communicating headings in spoken text. Practitioner Summary: The study attempted to identify effective ways of communicating heading information in spoken text. College students listened to texts in order to detect headings and record their wording and hierarchical level. Performance was excellent when headings were preceded by verbal phrases that signalled the upcoming headings and their levels.
Silver networks with high transmittance and low resistance were prepared on transparent substrates via a polymer-assisted electrospinning technique and post treatments. Nonaqueous media containing poly(methyl methacrylate) (PMMA) and silver trifluoroacetate (STA) were formulated and electrospun as polymer/metal-precursor nanofibers with as-spun fiber diameters ranging from 640 to 3000 nm. Nanofibers randomly deposited on transparent substrates formed a plane scaffold, which served as the raw material for the conducting silver network. Post-thermal treatment at a moderate temperature of 100 °C reduced the STA precursors to silver nanoparticles (Ag NPs). Further heat treatment at elevated temperatures thermally decomposed the organic polymer and triggered sintering of the Ag NPs into a connected one-dimensional (1D) domain. Silver fibers with diameters ranging between 800 and 4500 nm formed continuous conducting networks on the substrate surface. The sheet resistances of these conducting silver networks revealed strong correlations with the original STA/PMMA ratios and with the silver network morphologies after the polymers were removed. The material fabrication was carefully investigated, and the surface plasmon resonances (SPRs), fiber morphologies, and electrical and optical properties of the products were examined. The optimized conducting silver networks exhibited sheet resistances as low as 15 Ω/sq and diffusive optical transparencies of approximately 54%.
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