Evidence-based Explanations Research Articles

Warfarin resistance and enteral tube feeding: A vitamin K–independent interaction

Warfarin resistance associated with continuous enteral ube feedings was first reported in the early 1980s [1–5]. his resistance was originally attributed to the large mounts of vitamin K contained within the feedings. In the arly 1980s, patients often received as much as 1500 to 000 g of vitamin K per day or more [1–5]. Industry esponded to this significant drug–enteral feeding interacion by markedly decreasing the amount of vitamin K in heir liquid enteral feeding formulations (Table 1). Howver, despite this massive reduction in vitamin K content, I ave observed problems of achieving therapeutic anticoaglation when warfarin is given concomitantly with continous liquid enteral feeding or significant increases in the nternational normalized ratio (INR) for prothrombin time ithout a change in warfarin dosage when the enteral feedng is discontinued. The intent of this column is to discuss lausible “new” evidence-based explanations for this “old” rug–enteral tube feeding interaction.

Brokering at the boundary: A prospective science teacher engages students in inquiry

Using a theoretical perspective of communities of practice, this case study examines a prospective chemistry teacher's inquiry-based teaching during his practicum. Conrad was a former student of an inquiry-oriented science course, Inquiry Empowering Technologies (IET). The research questions were (a) How did Conrad translate the IET inquiry practices during his practicum?; (b) How did the mentor teacher shape Conrad's participation?; (c) In what ways did Conrad negotiate new meanings of inquiry as a result of his practicum? Interview transcripts were the primary data source. Conrad carried many of the IET inquiry practices into his practicum. He equated inquiry with the use of evidence and had students create evidence-based explanations for how soap works. He chose not to incorporate the tentative nature of science. Although traditional in his own teaching, the mentor teacher supported Conrad by allowing him to teach through inquiry and by removing time constraints. As a result of his practicum, Conrad negotiated new meanings of inquiry teaching and developed an expanded view of technology. Conrad believed that high school students needed guidance when engaging in inquiry and that the tentative nature of science does not transfer to secondary chemistry. Implications for theory and practice are given. © 2006 Wiley Periodicals, Inc. Sci Ed90:522–543, 2006

Scaffolding middle school students' coordination of theory and evidence

Evidence-based explanations are a core element of scientific reasoning. Nonetheless, the literature reports that students often fail to support their hypotheses with evidence, or give explanations that are not grounded in the data. This research examined the role of software scaffolding in supporting middle school students' coordination of theory and evidence. Students in 1 of the 2 classes in the study used an inquiry-support software tool to manage their investigation, whereas the students in the other class used science journals. We argue that the software-based scaffolding helped students coordinate theory with evidence while the science journal was not effective in helping students construct evidence-based explanations.