Discrepant Events Research Articles

Discrepancies in Identification of Bleeding Events After Percutaneous Coronary Intervention

To evaluate the level of agreement between two sets of criteria, the Thrombolysis in Myocardial Infarction (TIMI) criteria and investigator-developed criteria, for identifying bleeding events in patients who had undergone a percutaneous coronary intervention (PCI) and to measure length of hospital stay (LOS) as a surrogate marker of bleeding severity. Retrospective chart review. Two university-affiliated medical centers. Four hundred twenty-two consecutive patients who had undergone PCI from December 1, 2001-June 30, 2002. Data were collected on the number of bleeding events that occurred within 1 week after PCI (limited to one event/patient) and on LOS. Bleeding was assessed by TIMI criteria and by investigator-developed criteria. Bleeding according to TIMI criteria included intracranial hemorrhage, spontaneous hematuria or hematemesis, or decreases in hemoglobin level. Bleeding according to investigator-developed criteria included intracranial, retroperitoneal, intraocular, or clinically overt bleeding without a specified decrease in hemoglobin level. Agreement between criteria was assessed by means of the kappa statistic. Of the 422 patients, 23 (5%) experienced TIMI-defined bleeding events and 229 (54%) investigator-defined bleeding events. A kappa value of 0.09 (95% confidence interval 0.06-0.13) indicated a poor level of agreement between the two sets of bleeding criteria. The effect of this discrepancy on LOS was 66 fewer days of care when TIMI criteria were applied versus investigator-developed criteria in the 206 patients who experienced bleeding events that met investigator criteria (total LOS 645 days) but not TIMI criteria (total LOS 579 days). Bleeding assessment with use of TIMI criteria versus investigator-developed criteria yielded discrepant bleeding event rates and LOS, making it difficult to accurately compare bleeding rates and consequences across clinical trials and in practice. Consensus bleeding criteria are needed for applications in clinical evaluations of antithrombotic agents.

Core region of Arctic Oscillation and the main atmospheric events impact on the Arctic

Arctic Oscillation (AO) is a seesaw pattern in which sea level pressure (SLP) at the polar and middle latitudes in North Hemisphere fluctuates between positive and negative phases. It has been used as a representative atmospheric circulation index to express climate change. The purpose of this paper is to reveal the regional difference of SLP variation. By calculating the correlation coefficients of AO Index with all the gridded SLPs, we have uncovered a special region named as Arctic Oscillation Core Region (AOCR), where the running correlation coefficients (RCC) between gridded SLP and AO index are all negative. The averaged SLP of this region correlates significantly with the AO index. The correlations between local SLPs and AO index outside of AOCR are weaker than those inside. RCC analysis reveals several strong discrepant events different from AO. These events occurred in the years of 1954, 1955, 1962, 1971, 1982/83, 1995, 1996/97, 1998, and 1999. A comparison of these events and the ENSO or PDO indices suggests that the events in 1982/83 and 1998 are probably associated with the ENSO processes. Events centered in other years are likely connected with PDO, which reached their minima in the years of 1950, 1955, 1962 and 1971. The result in this study provides an alternative insight to look at the mechanism of the variation of Arctic Oscillation.

The First Three Minutes … of Class

Editor's Note: The importance of setting the tone from the beginning of class cannot be emphasized enough. Dr. Tim Slater, a frequent contributor to this column, shares some strategies to get students actively engaged in the lesson quickly using discrepant events and bell work tasks.

The Durability of Conceptual Change in Learning the Concept of Weight in the Case of a Pulley in Balance

This study concerns the question of how teachers can help pupils to perceive the concept of weight (gravitation). Fifth and ninth graders were asked in a paper-and-pencil test to compare the weight of two objects suspended in a pulley-in-balance half a year after the learning intervention consisting of three successive pulley-in-balance demonstrations. The understanding, that some of the fifth graders seemed to have formed from the weight concept after the teacher-independent learning intervention, had almost totally vanished in the delayed study. In the demonstrations the pulley served as an efficient prosthetic device for thinking, helping pupils to pay attention to the behaviour of the whole system instead of looking only at the separate objects. In the ninth grade about 45% of the pupils achieved general understanding about the pulley in balance by transferring the scientific explanation from the pulley demonstrations to the paper-and-pen test. A learning-with-conflict model is proposed based on pupil's alternative explanations about a discrepant event. These explanations are then challenged with a conflicting event. When pupils see and understand how the concept works in different contexts it is possible for the pupils to reach a context independent conceptual change.

Modelling Analysis of Students’ Processes of Generating Scientific Explanatory Hypotheses

It has recently been determined that generating an explanatory hypothesis to explain a discrepant event is important for students’ conceptual change. The purpose of this study is to investigate how students generate new explanatory hypotheses. To achieve this goal, questions are used to identify students’ prior ideas related to electromagnetic induction. After showing conflicting phenomena, six college students are asked to suggest explanatory hypotheses to explain the phenomena. Using interviews, the processes of generating explanatory hypotheses are analyzed and three types of hypotheses suggested by students are subsequently identified: theoretical, experiential, and auxiliary hypotheses. In addition, models of generating each type of explanatory hypothesis are also suggested. It is concluded that subjects use similarity‐based reasoning to relate their background knowledge or experiences with the conflicting phenomena to be explained. Background knowledge plays a very important role in generating new theoretical explanatory hypotheses. An example of a scientific inquiry activity for improving the skill of “generating scientific hypotheses” is also presented in this paper.

Neural correlates of olfactory change detection

Detecting changes in a stream of sensory information is vital to animals and humans. While there have been several studies of automatic change detection in various sensory modalities, olfactory change detection is largely unstudied. We investigated brain regions responsive to both passive and active detection of olfactory change using fMRI. Nine right-handed healthy, normosmic subjects (five men) were scanned in two conditions while breathing in synchrony with a metronome. In one condition, subjects mentally counted infrequent odors (Attend condition), whereas in the other condition, subjects' attention was directed elsewhere as they counted auditory tones (Ignore condition). Odors were delivered via a nasal cannula using a computer-controlled air-dilution olfactometer. Infrequently occurring olfactory stimuli evoked significant ( P < .05, corrected) activity in the subgenual cingulate and in central posterior orbitofrontal cortex, but only in the Ignore condition, as confirmed by direct comparison of the Ignore session with the Attend session ( P < .05, corrected). Subgenual cingulate and posterior orbital cortex may therefore play a role in detecting discrepant olfactory events while attention is otherwise engaged in another sensory modality.

The influence of students’ cognitive and motivational variables in respect of cognitive conflict and conceptual change

In this study, the relationships among students’ cognitive/motivational variables, cognitive conflict, and conceptual change were investigated. Subjects were 159 seventh graders in Korea. Tests regarding logical thinking ability, field dependence/independence (FDI), meaningful learning approach, failure tolerance, mastery goal orientation, and self‐efficacy were administered to examine students’ cognitive/motivational characteristics. A preconception test and a test of responses to discrepant event were also conducted to examine the degree of students’ cognitive conflict induced by a discrepant event. Computer‐assisted instruction, designed to change an undifferentiated weight‐density concept into a scientific density concept, was then provided to students as a conceptual change intervention. A conception test was administered as a post‐test. The results indicated that FDI was the only statistically significant variable correlated with the degree of cognitive conflict. A stepwise multiple regression analysis revealed that logical thinking ability, FDI, and failure tolerance were statistically significant predictors of the conception test scores. Educational implications are discussed.

Lasting effects of instruction guided by the conflict map: Experimental study of learning about the causes of the seasons

This study was based on the framework of the “conflict map” to facilitate student conceptual learning about causes of the seasons. Instruction guided by the conflict map emphasizes not only the use of discrepant events, but also the resolution of conflict between students' alternative conceptions and scientific conceptions, using critical events or explanations and relevant perceptions and conceptions that explicate the scientific conceptions. Two ninth grade science classes in Taiwan participated in this quasi-experimental study in which one class was assigned to a traditional teaching group and the other class was assigned to a conflict map instruction treatment. Students' ideas were gathered through three interviews: the first was conducted 1 week after the instruction; the second 2 months afterward; and the third at 8 months after the treatment. Through an analysis of students' interview responses, it was revealed that many students, even after instruction, had a common alternative conception that seasons were determined by the earth's distance to the sun. However, the instruction guided by the framework of the conflict map was shown to be a potential way of changing the alternative conception and acquiring scientific understandings, especially in light of long-term observations. A detailed analysis of students' ideas across the interviews also strongly suggests that researchers as well as practicing teachers need to pay particular attention to those students who can simply recall the scientific fact without deep thinking, as these students may learn science through rote memorization and soon regress to alternative conceptions after science instruction. © 2005 Wiley Periodicals, Inc. J Res Sci Teach 42: 1089–1111, 2005

Reexamining the Role of Cognitive Conflict in Science Concept Learning

In this study, we defined and quantified the degree of cognitive conflict induced by a discrepant event from a cognitive perspective. Based on the scheme developed, we investigated the relationship between cognitive conflict and conceptual change, and the influences of students' cognitive characteristics on conflict in learning the concept of density. Subjects were 171 seventh-grade girls from two city middle schools in Korea. Tests regarding logical thinking ability, field dependence/independence, and meaningful learning approach were administered. A preconception test and a test of responses to a discrepant event were also administered. Computer-assisted instruction was then provided to students as a conceptual change intervention. A conception test was administered as a posttest. In analysing students' responses to the discrepant event, seven types of responses were identified: Rejection, reinterpretation, exclusion, uncertainty, peripheral belief change, belief decrease, and belief change. These types were then ordered into four levels. The results indicated that there existed a significant correlation between cognitive conflict and conceptual change. t-test results revealed that there were statistically significant differences in the degree of cognitive conflict by the levels of students' logical thinking ability and field dependence/independence. Meaningful learning approach, however, was found to have no statistically significant effect on cognitive conflict. Educational implications are discussed.

Illusory sound shifts induced by the ventriloquist illusion evoke the mismatch negativity

The ventriloquist illusion arises when sounds are mislocated towards a synchronous but spatially discrepant visual event. Here, we investigated the ventriloquist illusion at a neurophysiological level. The question was whether an illusory shift in sound location was reflected in the auditory mismatch negativity (MMN). An ‘oddball’ paradigm was used whereby simultaneously presented sounds and flashes coming from the same location served as standard. The deviant consisted of a sound originating from the same source as the standard together with a flash at 20° spatial separation, which evoked an illusory sound shift. This illusory sound shift evoked an MMN closely resembling the MMN evoked by an actual sound shift. A visual-only control condition ruled out that the illusory-evoked MMN was confounded by the visual part of the audiovisual deviant. These results indicate that the crossmodal interaction on which the ventriloquist illusion is based takes place automatically at an early processing stage, within 200 ms after stimulus onset.

Beyond Surprise: The Puzzle of Infants' Expressive Reactions to Expectancy Violation.

The reactions of 58 infants to expectancy violation by digitally filtering the experimenter's voice were studied in a cross-sectional design for ages 5, 7, 9, 11-12, and 14 months. The results show that behavioral freezing and changes in gaze direction, but not facial or vocal expression, are reliable responses to expectancy violation. The pattern suggests that a transition in the infant's capacity for cognitive evaluation of novel and discrepant events may occur around age 9 months. These findings confirm the consistent failure to find prototypical facial surprise reactions in research on novel or impossible situations. Componential theories of emotion, which predict adaptive behavior patterns from appraisal processes, may provide clues for underlying mechanisms and generate hypotheses on age-related changes in emotional expression.

Light-curve classification in massive variability surveys -- I. Microlensing

This paper exploits neural networks to provide a fast and automatic way to classify light curves in massive photometric data sets. As an example, we provide a working neural network that can distinguish microlensing light curves from other forms of variability, such as eruptive, pulsating, cataclysmic and eclipsing variable stars. The network has five input neurons, a hidden layer of five neurons and one output neuron. The five input variables for the network are extracted by spectral analysis from the light-curve data points and are optimized for the identification of a single, symmetric, microlensing bump. The output of the network is the posterior probability of microlensing. The committee of neural networks successfully passes tests on noisy data taken by the MACHO collaboration. When used to process ∼5000 light curves on a typical tile towards the bulge, the network cleanly identifies the single microlensing event. When fed with a subsample of 36 light curves identified by the MACHO collaboration as microlensing, the network corroborates this verdict in the case of 27 events, but classifies the remaining nine events as other forms of variability. For some of these discrepant events, it looks as though there are secondary bumps or the bump is noisy or not properly contained. Neural networks naturally allow for the possibility of novelty detection; that is, new or unexpected phenomena which we may want to follow-up. The advantages of neural networks for microlensing rate calculations, as well as the future developments of massive variability surveys, are both briefly discussed.

Using a conflict map as an instructional tool to change student alternative conceptions in simple series electric-circuits

Research in science education has revealed that students have alternative conceptions when learning various domains in science. The conflict map uses a series of discrepant events, critical events, relevant scientific conceptions and perceptions to promote student conceptual change. This study was conducted to examine the effects of using a conflict map on eighth graders' conceptual change and ideational networks about simple series electric circuits. Through a quasi-experimental research design, 93 of Taiwan's eighth graders were assigned to a control group, receiving traditional instruction, while 97 eighth graders were assigned to an experimental group, which used a conflict map as an instructional tool. Research data gathered from a two-tier test revealed that the conflict map could help students overcome alternative conceptions about simple series electric circuits. Student interview data, analysed through a flow map method, also showed that the use of conflict map could help students construct greater, richer and more integrated ideational networks about electric circuits.

Step-Wise Evolution of Mental Models of Electric C ircuits: A "Learning-Aloud" Case Study

Various methods have been tried for fostering conceptual change in science including the use of analogies, discrepant events, and visual models. In this article we describe an approach to teaching complex models in science that takes a model construction cycle of generation, evaluation, and modification as an organizing framework for thinking about when to use each of the previous strategies. This approach of model evolution uses all of the previous methods as students are led to reassess and revise their model many times in the course of the lessons. We reported on the case study of a student in a tutoring experiment using this approach in the study of electric circuits. We concentrated on the student's moments of surprise as motivators of conceptual change. Most of these came from discrepant events, but 1 of them appeared to come from the student's own sensed lack of coherence in an intermediate model. In this case study, the teaching method appears to lead to the construction of an explanatory model that is fairly deeply understood by the student in the sense that it can generate predictions and coherent explanations of a complex system in a transfer problem. Some of our conclusions and hypotheses generated with respect to learning processes are as follows: (a) Discrepant events produced reactions of surprise and were eventually followed by model revisions, leading us to hypothesize a motivating and guiding role for these events; (b) the subject was able to map and apply an air pressure analogy used for electric potential and continued to exhibit traces of it through the posttest interview; (c) the subject's spontaneous use of similar depictive hand motions during the instruction and during the posttest provides initial evidence that the instruction fostered development of dynamic mental models, such as those of fluid-like flows caused by pressure differences, that can generate new mental simulations for understanding relatively difficult transfer problems. This leads us to describe the core of her new knowledge as explanatory models at an intermediate level of generality that allow her to run imagistic simulations and to hypothesize a "transfer of runnability" from the analog conception to the model in this case; (d) we hypothesize that the process underlying model generations and revisions was 1 of scaffolded abductive knowledge construction rather than induction or deduction; that evaluation and revision cycles can make up for the conjectural nature of individual abductions; and that engagement and comprehension in the cycle was fostered by small step sizes for revisions from using multiple "small" discrepant events and analogies built into the lessons.

Using Limiting-Excess Stoichiometry to Introduce Equilibrium Calculations: A Discrepant Event Laboratory Activity Involving Precipitation Reactions

The transition between limiting and excess stoichiometry and equilibrium calculations is demonstrated in a laboratory activity for introductory college chemistry students. Students are presented with two precipitation reactions and asked to predict the identity of any excess reactants in the filtrate, on the basis of mole calculations they have already learned. They find that in one of the reactions there are two excess reactants instead of only the one that they originally predicted. This "discrepant event" provides a motivating laboratory opportunity in which to introduce the concept of equilibrium, equilibrium calculations, and Ksp as reasonable explanations of the results.

A Model for Extending Hands‐On Science to Be Inquiry Based

Many popular hands‐on science activities, as traditionally implemented, fail to support inquiry‐based science instruction, because the activities direct teachers to terminate lessons prematurely. This paper presents a model describing one approach for extending seemingly limited hands‐on activities into full‐inquiry science lessons. The strategy involves (a) discrepant events to engage students in direct inquiry; (b) teacher‐supported brainstorming activities to facilitate students in planning investigations; (c) effective written job performance aids to provide structure and support; (d) requirements that students provide a product of their research, which usually includes a class presentation and a graph; and (e) class discussion and writing activities to facilitate students in reflecting on their activities and learning. The paper presents the model as a tool for facilitating science teachers' efforts to understand and implement the type of powerful, effective, and manageable inquiry‐based science instruction called for in the National Science Education Standards.

Enhancing science instruction: the use of 'conflict maps'

This paper proposes the use of 'conflict maps' as a way of enhancing science teaching and learning. The conflict map emphasizes not only the use of discrepant events, but also the resolution of the conflict between students' alternative conceptions and the scientific conception, using critical events or explanations and relevant perceptions and conceptions that explicate the scientific conception. The use of conflict maps is consistent with a conceptual change model suggested by science educators; hence, it is expected that the conflict map could help students overcome alternative conceptions and thus promote conceptual change. The conflict map, which clearly displays students' alternative conceptions and scientific conceptions, could be used as an instructional aid, helping science teachers construct or implement lesson plans, or as a metacognitive tool, helping learners monitor their ideas and the processes of conceptual change.

Using Computers to Support a Beginning Teacher's Professional Development

This study explored the efficacy of promoting a beginning chemistry teacher's curriculum development and teaching practices through the use of computers. Using pictorial analogies, historical cases of science, and discrepant events in a web site designed by the researchers as curricular samples, the beginning teacher was asked to develop similar curriculum for his own teaching. After taking the researchers' advice into account and making adjustments, the beginning teacher implemented the curriculum in his classroom teaching and shared his experience with the researchers by e-mail communications. The teacher's teaching practices both before and after the web site treatment were observed and analyzed. It was found that before the treatment the teacher used the textbook as the only resource of his teaching. Extra curriculum was rarely seen, there were not many student-teacher interactions, and analogies or examples used in his explanation of abstract concepts were not preorganized. On the other hand, after the treatment, the teacher was able to develop suitable curricula by himself for the purpose of increasing student involvement. He also explained the applications of chemical concepts in daily lives and his analogies and demonstrations were well organized. Although the beginning teacher was able to develop curricula after the treatment, many aspects of his teaching can be improved, especially in the areas of student-teacher interaction and the implementation of students activities in science teaching.

Children's concepts: Tools for transforming science teachers' knowledge

This study examined the roles that students' science concepts play in promoting teachers' professional growth. Two cohorts of teachers (N = 26 and 30) participated in the study as part of a constructivist-based graduate course on elementary and middle school science methods. A modified learning cycle was used during course instruction as a framework for teachers to explore sound, light, and electricity. Data on teachers' pedagogical and conceptual growth was obtained from pre- and postconcept maps, journal reflections, and portfolios. Results of the concept map analysis showed that teachers' maps became more integrated and cohesive as seen in the increase of crosslinks, hierarchies, and relationships drawn for each science topic. The journals and portfolios showed that students' science knowledge served as discrepant events that evoked teachers' dissatisfaction with their own content knowledge and motivated them to reconsider their pedagogical practices. Students' concepts also served as change agents, resulting in changes in teachers' views of their roles and instructional behaviors. © 1999 John Wiley & Sons, Inc. Sci Ed83:545–557, 1999.

Does Copper Metal React with Acetic Acid?

Starting with a discrepant event and led through a series of experiments, students of an introductory chemistry course investigate if copper metal reacts with acetic acid. Finding that oxygen from the air plays an important role in the reaction of these substances, students ultimately realize that the conditions under which two reactants interact are important in determining the type of products that are made. This laboratory activity, which could function as a discovery oriented experiment or as an individualized project, could be used to teach the importance of controlling variables, how to prepare common gases, as well as to discuss the electrochemical series, redox, the solubility of gases in water, and the concept of corrosion.