学会飞翔

我是怀着两个梦想长大的：一个梦想是骑单车，另一个是飞翔。现在我已经47岁了，而直到现在，我一个梦想郁还没有实现呢。其实这些梦想的种子萌发于我童年时做的两个梦。     

The importance of measuring growth in response to intervention models: Testing a core assumption

A core assumption of response to instruction or intervention (RTI) models is the importance of measuring growth in achievement over time in response to effective instruction or intervention. Many RTI models actively monitor growth for identifying individuals who need different levels of intervention. A large-scale (N=23,438), two-year longitudinal study of first grade children was carried out to compare the predictive validity of measures of achievement status, growth in achievement, and their combination for predicting future reading achievement. The results indicate that under typical conditions, measures of growth do not make a contribution to prediction that is independent of measures of achievement status. These results question the validity of a core assumption of RTI models.     

Computational auditory scene analysis: listening to several things at once

The problem of distinguishing particular sounds, such as conversation, against a background of irrelevant noise is a matter of common experience. Psychologists have studied it for some 40 years, but is is only comparatively recently that computer modelling of the phenomenon has been attempted. This article reviews progress made, possible practical applications, and prospects for the future.     

Responding to university policies and initiatives: the role of reflexivity in the mid-career academic

How do academics make sense of university policies and strategic initiatives and act on them? Interviews were conducted with 27 mid-career academics in different disciplines, different research-intensive university environments and two countries (England and Australia). Data were analysed iteratively utilising a critical realist perspective, specifically, Archer’s modes of reflexivity. The paper argues that individuals’ responses to university policies and initiatives, to changes in policy and policy conflicts, can at least partially be understood through interrogating the modes of reflexivity they employ.     

Discrimination and representation of relative numerosity in a bisection task by pigeons

We trained 4 pigeons in a numerical bisection task to discriminate between pairs of keylight flashes with a ratio of 1∶3 (2 vs. 6, 4 vs. 12, and 8 vs. 24) that were presented in a sample phase. Responses to the blue key were reinforced after a sequence of a larger number of flashes, and responses to the white key were reinforced after a sequence of a smaller number of flashes. The intervals between flashes in the sample phase were randomized to attenuate the covariation of temporal cues with flash number. Pigeons responded accurately in each of the discriminations, with typically 85%–90% correct responses. Transfer tests showed that the proportion of large responses increased with number and performance generalized to larger values outside the training ranges. Psychometric functions superposed when plotted on a relative scale, and estimates of Weber fractions were approximately constant, suggesting that variability was scalar. However, contrary to previous research in nonhumans, bisection points were located at the arithmetic, not geometric, mean. Hierarchical logistic regressions confirmed significant control over responding by number beyond that attributable to temporal cues. These results show that pigeons are able to respond accurately in a relative numerosity discrimination with successively presented visual stimuli, although the nature of the numerical representation and response rule remains unclear.     

How do pre-kindergarteners spend their time? Gender,ethnicity, and income as predictors of experiences in pre-kindergarten classrooms

The current paper considers how children spend their time in state-funded pre-kindergarten programs and how time use relates to ethnicity, gender, and family income, based on the assumption that how time is spent in pre-kindergarten is relevant for the programs’ success in narrowing achievement gaps. Classroom observations of 2061 children in 652 pre-k programs in 11 states were analyzed. Findings indicated that the pre-kindergarten day was roughly equally divided among free choice, teacher-assigned activities, and meals/routines. Children spent much of their time in language/literacy, social studies, and art, and less time in math and gross motor activities. Much of the pre-k day was spent in ‘no coded learning activity.’ Children in classes with lower proportions of Latino and African American children and higher average income-to-need ratios were generally engaged in richer and more stimulating experiences. The child-level variables of ethnicity and income were generally unrelated to how children spent their time, above and beyond the effects of classroom-level ethnicity and income. There were generally small, but significant gender differences – always in the gender-stereotyped direction – in how time was spent, especially during free choice time.     

"I Follow the Blue..." A Primary Teacher and the Impact of Packaged Curricula

In the primary grades, literacy teachers often face dual and competing challenges. On one hand, they are expected to provide developmentally appropriate practice in a contextually-sensitive manner. On the other hand, they are often charged with using packaged literacy curricula that contains components that are developmentally inappropriate for young learners. This piece provides a case study of the impact of mandated packaged curricula on one such teacher's beliefs and pedagogy.     

Measurements of drag and lift on tennis balls in flight

Measurements are presented of drag and lift on new tennis balls in flight. Two video cameras were used to measure the velocity and height of the balls at two positions separated horizontally by 6.4 m. The balls were fired from a ball launcher at speeds between 15 and 30 m/s and with topspin or backspin at rates up to 2,500 rpm. Significant shot-to-shot variations were found in both the drag and lift coefficients. The average drag coefficient was 0.507 ± 0.024, independent of ball speed or spin, and lower than the value usually observed in wind tunnel experiments. The lift coefficient increased with ball spin, on average, but significant lift was observed even at very low spin. The latter effect can be attributed to a side force arising from asymmetries in the ball surface, analogous to the side force responsible for the erratic path of a knuckleball in baseball.