Ultrasonic phased array technology for the non-destructive testing of marble sculptures

The medical ultrasonic phased array technology was modified for the non-destructive testing of marble sculptures and the feasibility of the approach was evaluated. For this purpose, 1?MHz, 64-channel phased array electronic and phased array transducers were developed. The specifications of the electronics and the transducers are presented and discussed. Ultrasound images of inner structures of a marble sculpture are presented. The problem of the acoustic matching layers for different states of deterioration is discussed and the developments in view of a suitable matching layer solution are presented. This matching layer is combined with a new coupling technique that protects the marble surface. The results of experiments on ultrasound phantoms and on a marble sculpture are presented.     

Does generating examples aid proof production?

Many mathematics education researchers have suggested that asking learners to generate examples of mathematical concepts is an effective way of learning about novel concepts. To date, however, this suggestion has limited empirical support. We asked undergraduate students to study a novel concept by either tackling example generation tasks or reading worked solutions to these tasks. Contrary to suggestions in the literature, we found no advantage for the example generation group on subsequent proof production tasks. From a second study, we found that undergraduate students overwhelmingly adopt a trial and error approach to example generation and suggest that different example generation strategies may result in different learning gains. We conclude by arguing that the teaching strategy of example generation is not yet understood well enough to be a viable pedagogical recommendation.     

Children's Emotionality Moderates the Association Between Maternal Responsiveness and Allostatic Load: Investigation Into Differential Susceptibility

While emotionality is often thought of as a risk factor, differential susceptibility theory argues that emotionality reflects susceptibility to both positive and negative environmental influences. The present study explored whether emotional children might be more susceptible to the effects of both high and low maternal responsiveness on allostatic load, a physiological indicator of chronic stress. Participants were 226 mother and child dyads. Mothers reported on children's emotionality at child age 9. Maternal responsiveness was measured at age 13 using self‐reports and behavioral observation. Allostatic load was measured at age 13 and 17 using neuroendocrine, cardiovascular, and metabolic biomarkers. Emotionality was associated with higher allostatic load if self‐reported responsiveness was low, but with lower allostatic load, when self‐reported responsiveness was high.     

Learning opportunities from group discussions: warrants become the objects of debate

In the mathematics education literature, there is currently a debate about the mechanisms by which group discussion can contribute to mathematical learning and under what conditions this learning is likely to occur. In this paper, we contribute to this debate by illustrating three learning opportunities that group discussions can create. In analyzing a videotaped episode of eight middle school students discussing a statistical problem, we observed that these students frequently challenged the arguments that their colleagues presented. These challenges invited students to be explicit about what mathematical principles, or warrants, they were implicitly using as a basis for their mathematical claims, in some cases recognize the modes of reasoning they were using were invalid and reject these modes of reasoning, and in other cases, attempt to provide deductive support to justify why their modes of reasoning were appropriate. We then describe what social and environmental conditions allowed the discussion analyzed in this paper to occur.

College Students’ Psychological Needs and Intrinsic Motivation to Learn: An Examination of Self-Determination Theory

Over the last several decades, instructional communication scholars have studied and measured student motivation as an important learning outcome. Unfortunately, this research has lacked theoretical guidance and has treated student motivation as a construct that varies only in quantity, ignoring existing theory that suggests student motivation is best understood as a construct that differs in quality (i.e., intrinsic motivation). To create two new measures that incorporate theoretical explanations of student motivation, three studies (N = 1,067) were undertaken using self-determination theory (SDT) to operationalize students’ intrinsic motivation as a product of basic psychological need satisfaction. In the first two studies, the Student Psychological Needs Scale and the Intrinsic Motivation to Learn Scale were developed and validated. In the third study, parallel mediation analyses supported SDT’s prediction that the fulfillment of students’ psychological needs (i.e., autonomy, competence, relatedness) would mediate the relationship between personalized education practices and intrinsic motivation to learn.     

Take home tests: An experimental study

The take home test was compared with the conventional closed and open book tests at the college level. It was found that scores on knowledge items were significantly higher with the take home test, and that additional time spent looking up answers was important. An additional factor was the level of anxiety, perceived by students to be less with the take home test. Rampant cheating does not appear to be a problem with take home tests.