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71.
U.S. federal websites are required to be accessible for people with impairments. However, despite the existing regulations and guidelines, many federal websites continue to be inaccessible, and accessibility policy statements available on federal websites often do not provide any useful information. This paper provides three contributions to the research literature: (1) an accessibility evaluation of 100 federal home pages using both human and automated methods, (2) a content analysis of existing website accessibility policy statements, and (3) a discussion of the relationship between actual Section 508 compliance and the existing accessibility policy statements on a website. The paper concludes with recommendations for improving policy related to Section 508 compliance for websites.  相似文献   
72.
As advances in microfluidics continue to make contributions to diagnostics and life sciences, broader awareness of this expanding field becomes necessary. By leveraging low-cost microfabrication techniques that require no capital equipment or infrastructure, simple, accessible, and effective educational modules can be made available for a broad range of educational needs from middle school demonstrations to college laboratory classes. These modules demonstrate key microfluidic concepts such as diffusion and separation as well as "laboratory on-chip" applications including chemical reactions and biological assays. These modules are intended to provide an interdisciplinary hands-on experience, including chip design, fabrication of functional devices, and experiments at the microscale. Consequently, students will be able to conceptualize physics at small scales, gain experience in computer-aided design and microfabrication, and perform experiments-all in the context of addressing real-world challenges by making their own lab-on-chip devices.  相似文献   
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Separation and sorting of biological entities (viruses, bacteria, and cells) is a critical step in any microfluidic lab-on-a-chip device. Acoustofluidics platforms have demonstrated their ability to use physical characteristics of cells to perform label-free separation. Bandpass-type sorting methods of medium-sized entities from a mixture have been presented using acoustic techniques; however, they require multiple transducers, lack support for various target populations, can be sensitive to flow variations, or have not been verified for continuous flow sorting of biological cells. To our knowledge, this paper presents the first acoustic bandpass method that overcomes all these limitations and presents an inherently reconfigurable technique with a single transducer pair for stable continuous flow sorting of blood cells. The sorting method is first demonstrated for polystyrene particles of sizes 6, 10, and 14.5 μm in diameter with measured purity and efficiency coefficients above 75 ± 6% and 85 ± 9%, respectively. The sorting strategy was further validated in the separation of red blood cells from white blood cells and 1 μm polystyrene particles with 78 ± 8% efficiency and 74 ± 6% purity, respectively, at a flow rate of at least 1 μl/min, enabling to process finger prick blood samples within minutes.  相似文献   
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When designing a reading intervention, researchers and educators face a number of challenges related to the focus, intensity, and duration of the intervention. In this paper, we argue there is another fundamental challenge—the nature of the reading outcome measures used to evaluate the intervention. Many interventions fail to demonstrate significant improvements on standardized measures of reading comprehension. Although there are a number of reasons to explain this phenomenon, an important one to consider is misalignment between the nature of the outcome assessment and the targets of the intervention. In this study, we present data on three theoretically driven summative reading assessments that were developed in consultation with a research and evaluation team conducting an intervention study. The reading intervention, Reading Apprenticeship, involved instructing teachers to use disciplinary strategies in three domains: literature, history, and science. Factor analyses and other psychometric analyses on data from over 12,000 high school students revealed the assessments had adequate reliability, moderate correlations with state reading test scores and measures of background knowledge, a large general reading factor, and some preliminary evidence for separate, smaller factors specific to each form. In this paper, we describe the empirical work that motivated the assessments, the aims of the intervention, and the process used to develop the new assessments. Implications for intervention and assessment are discussed.  相似文献   
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Proposing that bilingual proficiency should produce a more favorable attitude toward bilingualism and should enhance one's self-esteem, the authors compared 57 bilingual and 67 unilingual students from grades 9, 10, and 11, measuring their opinions about bilingualism and their self-esteem. The bilingual students are substantially more favorably disposed toward bilingualism than the unilingual students are. On the Janis-Field scale of self-esteem, the bilingual students show greater self-esteem than the unilingual students. The largest differences between the groups are on questions that measure self-confidence and social ease; differences are less pronounced on questions about self-worth and about shyness. We speculate that bilingual proficiency offers some psychological advantages to students who achieve it.  相似文献   
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