Based on conceptual change theory, cognitive conflict is known as an important factor in conceptual change even though there are still questions about its positive and negative effects on science learning. However, there is no reliable method by which to assess the cognitive conflict students experience in their learning. The purpose of this research was to develop an instrument for measuring secondary students' cognitive conflict levels as they learned science. The results of this study indicate that our instrument is a valid and reliable tool for measuring cognitive conflict levels. Factor analysis supported the model that cognitive conflict consists of four constructs: recognition of an anomalous situation, interest, anxiety, and cognitive reappraisal of the conflict situation. Implications for instruction and possibilities for future research are discussed. © 2003 Wiley Periodicals, Inc. J Res Sci Teach 40: 585–603, 2003

No abstract

Transmission electron microscopy with in situ biasing has been performed on TiN/single‐crystal rutile TiO2/Pt resistive switching structures. Three elementary processes essential for switching: i) creation of oxygen vacancies by electrochemical reactions at low temperatures (<150 °C), ii) their drift in the electric field, and iii) their coalescence into planar faults (and dissociation from them) have been documented. The faults have a form of vacancy discs in {110} and {121} planes, are bound by partial dislocation loops, and are identical to Wadsley defects observed in nonstoichiometric TiO2 annealed at high temperatures. The faults can be regarded as a precursor to the formation of oxygen‐deficient Magnéli phases, but 3D secondary phase inclusions have not been detected. Together, the observations shed light on the behavior of oxygen vacancies in relatively low electric fields and temperatures, suggesting that, in addition to the rather accepted notion of oxygen vacancy motion during the writing processes in resistive switching devices, such motion may occur even during reading, and may be accompanied by significant oxygen vacancy creation at modest device excitation levels.

Platelet function and fatty acid composition were investigated in 30 healthy male subjects who ate a controlled-saturated-fatty-acid (baseline) diet for 3 wk and then consumed either safflower oil or canola oil as a major fat source for 8 wk. Fatty acid composition of platelet phospholipids reflected changes in dietary fatty acid composition. Compared with baseline a 35% decrease (P less than 0.05) in arachidonic acid was observed in platelet phospholipids of the canola-oil diet group while long chain n-3 fatty acids rose 7-26% (P greater than 0.05). Compared with baseline both unsaturated-fatty-acid diets reduced platelet aggregation at 3 wk of oil-based diet feeding (P less than 0.01) whereas only canola oil influenced platelet function (lowered ATP secretion) at 8 wk (P less than 0.01). No significant difference was observed in thromboxane B2 concentrations between oil-treatment groups at 8 wk. Both oil-based diets had short-term beneficial effects on platelet function but the effect of canola oil persisted longer.

No abstract