Rationale: Several studies suggest that nasal nitric oxide (nNO) measurement could be a test for primary ciliary dyskinesia (PCD), but the procedure and interpretation have not been standardized.Objectives: To use a standard protocol for measuring nNO to establish a diseasespecific cutoff value at one site, and then validate at six other sites.Methods: At the lead site, nNO was prospectively measured in individuals later confirmed to have PCD by ciliary ultrastructural defects (n = 143) or DNAH11 mutations (n = 6); and in 78 healthy and 146 disease control subjects, including individuals with asthma (n = 37), cystic fibrosis (n = 77), and chronic obstructive pulmonary disease (n = 32). A disease-specific cutoff value was determined, using generalized estimating equations (GEEs). Six other sites prospectively measured nNO in 155 consecutive individuals enrolled for evaluation for possible PCD. Measurements and Main Results:At the lead site, nNO values in PCD (mean 6 standard deviation, 20.7 6 24.1 nl/min; range, 1.5-207.3 nl/min) only rarely overlapped with the nNO values of healthy control subjects (304.6 6 118.8; 125.5-867.0 nl/min), asthma (267.8 6 103.2; 125.0-589.7 nl/min), or chronic obstructive pulmonary disease (223.7 6 87.1; 109.7-449.1 nl/min); however, there was overlap with cystic fibrosis (134.0 6 73.5; 15.6-386.1 nl/min). The disease-specific nNO cutoff value was defined at 77 nl/minute (sensitivity, 0.98; specificity, .0.999). At six other sites, this cutoff identified 70 of the 71 (98.6%) participants with confirmed PCD.Conclusions: Using a standardized protocol in multicenter studies, nNO measurement accurately identifies individuals with PCD, and supports its usefulness as a test to support the clinical diagnosis of PCD.

The purpose of this study was to explore in greater depth what has been called by previous researchers, a deep versus surface approach to learning science. Six Grade 8 students judged as typically using learning approaches ranging from deep to surface were observed and taped during class group laboratory activities in a chemistry unit. They were also interviewed individually before and after instruction about related science concepts. On analysis of the students' discourse and actions during the activities and their interview responses, several differences in learning approaches seemed apparent. These differences fell into five emergent categories: generative thinking, nature of explanations, asking questions, metacognitive activity, and approach to tasks. When students used a deep approach, they ventured their ideas more spontaneously; gave more elaborate explanations which described mechanisms and cause-effect relationships or referred to personal experiences; asked questions which focused on explanations and causes, predictions, or resolving discrepancies in knowledge; and engaged in "on-line theorizing." Students using a surface approach gave explanations that were reformulations of the questions, a "black box" variety which did not refer to a mechanism, or macroscopic descriptions which referred only to what was visible. Their questions also referred to more basic factual or procedural information. The findings also suggest that to encourage a deep learning approach, teachers could provide prompts and contextualized scaffolding and encourage students to ask questions, predict, and explain during activities. © 2000 John Wiley & Sons, Inc. J Res Sci Teach 37: 2000 Some students are more successful than others in learning science. This may be due to differences in the way students learn-whether it is meaningful or rote learning (Ausubel, 1968). Meaningful learning requires relevant prior knowledge, meaningful learning tasks, and a meaningful learning set (Novak, 1988). In contrast, rote learning is arbitrary, verbatim, and not related to experience with events or objects, and lacks affective commitment on the part of the learner to relate new and prior knowledge. The nature of students' learning-that is, meaningful or rote-is related to the construct "approaches to learning." JOURNAL OF RESEARCH IN SCIENCE TEACHING VOL. 37, NO. 2, PP. 109-138 (2000) © 2000 John Wiley & Sons, Inc.Correspondence to: C. Chin Approaches to LearningApproaches to learning or learning approaches refer to "the ways in which students go about their academic tasks, thereby affecting the nature of the learning outcome" (Biggs, 1994). Research on approaches to learning derives much from the seminal work of Marton and Saljo (1976) on reading from text using phenomenographic methods, where learning is studied from the perspective of the learner, based on qualitative analysis of interview data and descriptive analyses of differences between the learning behaviors of small numbers of students. These authors distinguished betw...

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In most work investigating factors influencing the success of analogies in instruction, an underlying assumption is that students have little or no knowledge of the target situation (the situation to be explained by analogy). It is interesting to ask what influences the success of analogies when students believe they understand the target situation. If this understanding is not normative, instruction must aim at conceptual change rather than simply conceptual growth. Through the analysis of four case studies of tutoring interviews (two of which achieved some noticeable conceptual change and two of which did not) we propose a preliminary list of factors important for success in overcoming misconceptions via analogical reasoning. First, there must be a usable anchoring conception. Second, the analogical connection between an anchoring example and the target situation may need to be developed explicitly through processes such as the use of intermediate, "bridging" analogies. Third, it may be necessary to engage the student in a process of analogical reasoning in an interactive teaching environment, rather than simply presenting the analogy in a text or lecture, Finally, the result of this process may need to be more than analogical transfer of abstract relational structure. The analogies may need to be used to enrich the target situation, leading to the student's construction of a new explanatory model.