Removing opportunities to calculate improves students' performance on subsequent word problems.

BackgroundIn two studies we investigated whether removing opportunities to calculate could improve students' subsequent ability to solve similar word problems. Students were first asked to write explanations for three word-problems that they thought would help another student understand the problems. Half of the participants explained typical word problems (i.e., problems with enough information to make calculating an answer possible), while the other half explained the same problems with numbers removed, making calculating an answer impossible. We hypothesized that removing opportunities to calculate would induce students to think relationally about the word problems, which would result in higher levels of performance on subsequent transfer problems.ResultsIn both studies, participants who explained the non-calculable problems performed significantly better on the transfer test than participants who explained the typical (i.e., calculable) problems. This was so in spite of the manipulation not fully suppressing students' desire to calculate. Many students in the non-calculable group explicitly stated that they needed numbers in order to answer the question or made up numbers with which to calculate. There was a significant, positive relationship between the frequency with which students made up numbers and their self-reported mathematics anxiety.ConclusionsWe hypothesized that the mechanism at play was a reduction in instrumental thinking (and an increase in relational thinking). Interventions designed to help students remediate prior mathematical failure should perhaps focus less on the specific skills students are lacking, and more on the dispositions they bring to the task of "doing mathematics.

Value-added Teacher Estimates as Part of Teacher Evaluations: Exploring the Effects of Data and Model Specifications on the Stability of Teacher Value-added Scores

In this study we explored the effects of statistical controls, single versus multiple cohort models, and student sample size on the stability of teacher value-added estimates (VAEs). We estimated VAEs for all 5th grade mathematics teachers in a large urban district by fitting two level mixed models using four cohorts of student data. We found that student sample size had the largest effect on changes in teachers’ relative standing and designation into performance groups, while control variables affected VAEs only minimally. However, we also found that teacher VAEs showed a fair degree of stability; year-to-year correlations ranged between .62 and .66, and changes in teacher effectiveness systematically varied by teacher experience, with beginning teachers showing the largest improvements over the four years under study.  Our results suggest that some model specifications are likely to produce teacher value-added scores that can reflect meaningful differences in teachers while we also found that other models might produce VAEs that might be unreliable.   

Emergence of long memory in stock volatility from a modified Mike-Farmer model

The Mike-Farmer (MF) model was constructed empirically based on the continuous double auction mechanism in an order-driven market, which can successfully reproduce the cubic law of returns and the diffusive behavior of stock prices at the transaction level. However, the volatility (defined by absolute return) in the MF model does not show sound long memory. We propose a modified version of the MF model by including a new ingredient, that is, long memory in the aggressiveness (quantified by the relative prices) of incoming orders, which is an important stylized fact identified by analyzing the order flows of 23 liquid Chinese stocks. Long memory emerges in the volatility synthesized from the modified MF model with the DFA scaling exponent close to 0.76, and the cubic law of returns and the diffusive behavior of prices are also produced at the same time. We also find that the long memory of order signs has no impact on the long memory property of volatility, and the memory effect of order aggressiveness has little impact on the diffusiveness of stock prices.Comment: 6 pages, 6 figures and 1 tabl

Numerical indications of a q-generalised central limit theorem

We provide numerical indications of the $q$-generalised central limit theorem that has been conjectured (Tsallis 2004) in nonextensive statistical mechanics. We focus on $N$ binary random variables correlated in a {\it scale-invariant} way. The correlations are introduced by imposing the Leibnitz rule on a probability set based on the so-called $q$-product with $q \le 1$. We show that, in the large $N$ limit (and after appropriate centering, rescaling, and symmetrisation), the emerging distributions are $q_e$-Gaussians, i.e., $p(x) \propto [1-(1-q_e) \beta(N) x^2]^{1/(1-q_e)}$, with $q_e=2-\frac{1}{q}$, and with coefficients $\beta(N)$ approaching finite values $\beta(\infty)$. The particular case $q=q_e=1$ recovers the celebrated de Moivre-Laplace theorem.Comment: Minor improvements and corrections have been introduced in the new version. 7 pages including 4 figure

Weak temporal signals can synchronize and accelerate the transition dynamics of biopolymers under tension

In addition to thermal noise, which is essential to promote conformational transitions in biopolymers, cellular environment is replete with a spectrum of athermal fluctuations that are produced from a plethora of active processes. To understand the effect of athermal noise on biological processes, we studied how a small oscillatory force affects the thermally induced folding and unfolding transition of an RNA hairpin, whose response to constant tension had been investigated extensively in both theory and experiments. Strikingly, our molecular simulations performed under overdamped condition show that even at a high (low) tension that renders the hairpin (un)folding improbable, a weak external oscillatory force at a certain frequency can synchronously enhance the transition dynamics of RNA hairpin and increase the mean transition rate. Furthermore, the RNA dynamics can still discriminate a signal with resonance frequency even when the signal is mixed among other signals with nonresonant frequencies. In fact, our computational demonstration of thermally induced resonance in RNA hairpin dynamics is a direct realization of the phenomena called stochastic resonance (SR) and resonant activation (RA). Our study, amenable to experimental tests using optical tweezers, is of great significance to the folding of biopolymers in vivo that are subject to the broad spectrum of cellular noises.Comment: 22 pages, 7 figure

KONDE - A network brings together research and GLAM institutions. A project report

Seit Frühjahr 2017 läuft als Hochschulraum-Strukturmittel-Projekt das „Kompetenznetzwerk Digitale Edition“ (KONDE), das sich den Prämissen der Open Science Community verpflichtet fühlt und darauf zielt, Voraussetzungen für die Etablierung einer nachhaltigen, nationalen Publikationsplattform für Digitale Editionen (DE) für geistes-, sozial- und kulturwissenschaftliche Disziplinen (GSK) zu schaffen. Beiträger*innen der Universitäten Graz, Innsbruck, Klagenfurt, Salzburg und Wien, sowie der Technischen Universität Graz und der Kunstuniversität Graz, gemeinsam mit Fachkolleg*innen der Österreichischen Nationalbibliothek, der Österreichischen Akademie der Wissenschaften und des Adalbert Stifter-Instituts des Landes Oberösterreich haben sich das Ziel ge­setzt, eine Forschungsinfrastruktur für Digitale Editionen aufzubauen und österreichweit vorhandene Kompetenzen in diesem Bereich zu bündeln. Diese Infrastruktur soll keinesfalls nur als Hardware-Lösung oder Sammlung technischer Lösungsansätze verstanden werden, sondern möchte das Thema DE auch aus methodisch-theoretischer Sicht systematisch aufarbeiten und die Arbeits- und Diskussionsergebnisse der einschlägigen Scientific Community in einem interaktiven Weißbuch „Digitale Edition“ zur Verfügung stellen.The project “Kompetenznetzwerk Digital Edition” (KONDE) is funded by the Federal Ministry of Science, Research and Economy and has been operational since spring 2017. It is committed to the premises of the Open Science Community and aims to create conditions for the establishment of a sustainable publication platform for digital editions (DE). Contributors from the Universities Graz, Innsbruck, Klagenfurt, Salzburg and Vienna, the Technical University Graz and the University of Arts Graz together with colleagues from the Austrian National Library, the Austrian Academy of Sciences and the Adalbert Stifter Institute of the Province of Upper Austria, have set themselves the goal of establishing a research infrastructure for digital editions and pooling their expertise in this field throughout Austria. This infrastructure should by no means be understood merely as a hardware solution or a collection of technical solutions. It will also approach the topic of DE from a methodological-theoretical point of view and make the work and discussion results available to the scientific community in an interactive white paper on digital editing

Does recognition memory improve with age?

In order to test the hypothesis that recognition is a developmentally stable component of the memory system, age differences in recognition of faces were examined while controlling for nonmemory factors that might contribute to differences between the groups. Three groups of children (mean ages: 3 years, 4 months; 4 years, 9 months; and 6 years, 11 months) and a group of college students were tested on a recognition task and a similar matching task. The results indicated no change in recognition across the preschool years but an improvement from the later preschool period to the first grade. Further analyses indicated that this improvement was not due to changes in decision criteria or perceptual skills. These findings call into question the view that recognition is a developmentally invariant component of the memory system.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24243/1/0000506.pd

Family Variables and Reading

others of poor and average readers in Japan, Taiwan and the United States were iterviewed about their child-rearing practices, attitudes, and beliefs, and their children's current and earlier experiences. Poor readers represented the lowest fifth percentile in reading scores; they were matched by classroom, sex, and age with average readers; i.e., children who obtained reading scores within one standard deviation from the mean. The groups seldom differed significantly according to environmental variables and parent-child interactions. Maternal ratings of cognitive and achievement variables differentiated both the children in the two groups and the mothers themselves. Maternal beliefs and descriptions of how children use time also differed between the two groups. Notable was the absence of significant interactions between country and reading level.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68579/2/10.1177_002221948401700305.pd