Comprehension of arithmetic word problems: A comparison of successful and unsuccessful problem solvers.

It is proposed that when solving an arithmetic word problem, unsuccessful problem solvers base their solution plan on numbers and keywords that they select from the problem (the direct translation strategy), whereas successful problem solvers construct a model of the situation described in the problem and base their solution plan on this model (the problem-model strategy). Evidence for this hypothesis was obtained in 2 experiments. In Experiment 1, the eye fixations of successful and unsuccessful problem solvers on words and numbers in the problem statement were compared. In Experiment 2, the degree to which successful and unsuccessful problem solvers remember the meaning and exact wording of word problems was examined. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Invariant and dual subtraction games resolving the Duchêne–Rigo conjecture

We prove a recent conjecture of Duchêne and Rigo, stating that every complementary pair of homogeneous Beatty sequences represents the solution to an invariant impartial game. Here invariance means that each available move in a game can be played anywhere inside the game board. In fact, we establish such a result for a wider class of pairs of complementary sequences, and in the process generalize the notion of a subtraction game. Given a pair of complementary sequences $\left(a_n\right)$ and $\left(b_n\right)$ of positive integers, we define a game $G$ by setting $\left\{\{a_n,b_n\}\right\}$ as invariant moves. We then introduce the invariant game $G^{?}$, whose moves are all non-zero $P$-positions of $G$. Provided the set of non-zero $P$-positions of $G^{?}$ equals $\left\{\{a_n,b_n\}\right\}$, this is the desired invariant game. We give sufficient conditions on the initial pair of sequences for this ‘duality’ to hold.     

Narrow linewidth, tunable Tm3+-doped fluoride fiberlaser for optical-based hydrocarbon gas sensing

Operation of an efficient continuous-wave (CW) thulium-doped fiber laser emitting at wavelength, λ=2.31 μm is reported. The fiber laser parameters are optimized with a view to ultimately producing a compact and efficient laser source for optical absorption based gas sensing. A number of fiber laser configurations are investigated to assess their suitability for narrow linewidth, tunable fiber laser operation emitting around λ=2.3 μm, which is a wavelength region of significant importance for hydrocarbon gas monitoring. Tuning ranges of 140 nm and linewidths of less than 210 MHz have been demonstrated with lasers with bulk external tuning grating. Preliminary hydrocarbon gas sensing investigation confirm the potential of this source for detection of ppb gas concentrations     

An indirect testing approach for characterizing pressure profiles of compression bandages and hosiery

As outlined in compression therapy literature, the performance of a compression textile can be characterized by its stiffness and interface pressure. In this study, an indirect approach for measuring pressure from a set of compression bandages and hosiery was developed, from which rigidity (EI) values were determined, and tension–elongation curves and pressure-elongation data were calculated. The calculated pressure values were compared against PicoPress sensor readings measured on 10 participants. Results showed that the correlation between both approaches varied among bandage and hosiery samples.     

Getting a handle on learning anatomy with interactive three-dimensional graphics.

In 2 experiments, participants learned bone anatomy by using a handheld controller to rotate an on-screen 3-dimensional bone model. The on-screen bone either included orientation references, which consisted of visible lines marking its axes (orientation reference condition), or did not include such references (no–orientation reference condition). The learning task involved rotating the on-screen bone to match target orientations. Learning outcomes were assessed by asking participants to identify anatomical features from different orientations. On the learning task, the orientation reference group performed more accurately, directly, and quickly than did the control group, and high-spatial-ability individuals outperformed low-spatial-ability individuals. Assessments of anatomy learning indicated that under more challenging conditions, orientation references elevated learning by low-spatial-ability individuals to a level near that of high-spatial-ability individuals. The authors propose that orientation references assist this learning process by defining the object’s main axes or providing distinguishable features. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of social category norms and stereotypes on explanations for intergroup differences.

A 2-stage model of the construction of explanations for differences between groups is presented. Category norms affect which of 2 groups becomes "the effect to be explained," and stereotypes shape attributions about that group. In 3 experiments, 288 participants wrote explanations for differences between gay and straight men. Explanations focused on gay men who were also judged to have more mutable attributes. However, these effects were not correlated. Participants focused explanations on straight men when explicitly instructed to do so (Experiment 1). Explanations focused on both groups equally when the gay men constituted the numerically larger sample, when gay men were more typical of the overarching category (i.e., people with AMS) than straight men, or when more straight men were described as performing the behavior (Experiment 2). Stereotype-consistent information prompted more essentialist references and fewer reconstructive references to gay men than did stereotype-inconsistent information (Experiment 3). The relevance of this model for theories of norms, stereotypes, and for the conduct of social science is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inferring Cross-Sections: When Internal Visualizations Are More Important Than Properties of External Visualizations

Three experiments examined how cognitive abilities and qualities of external visualizations affected performance of a mental visualization task; inferring the cross-section of a complex three-dimensional object. Experiment 1 investigated the effect of animations designed to provide different task-relevant views of the external object. Experiment 2 examined the effects of both stereoscopic and motion-based depth cues. Experiment 3 examined the effects of interactive animations, with and without stereoscopic viewing conditions. In all experiments, spatial and general reasoning abilities were measured. Effects of animation, stereopsis, and interactivity were relatively small and did not reach statistical significance. In contrast, spatial ability was significantly associated with superior performance in all experiments, and this remained true after controlling for general intelligence. The results indicate that difficulties in this task stem more from the cognitive ability to perform the relevant internal spatial transformations, than limited visual information about the three-dimensional structure of the object.     

When Static Media Promote Active Learning: Annotated Illustrations Versus Narrated Animations in Multimedia Instruction.

In 4 experiments, students received a lesson consisting of computer-based animation and narration or a lesson consisting of paper-based static diagrams and text. The lessons used the same words and graphics in the paper-based and computer-based versions to explain the process of lightning formation (Experiment 1), how a toilet tank works (Experiment 2), how ocean waves work (Experiment 3), and how a car's braking system works (Experiment 4). On subsequent retention and transfer tests, the paper group performed significantly better than the computer group on 4 of 8 comparisons, and there was no significant difference on the rest. These results support the static media hypothesis, in which static illustrations with printed text reduce extraneous processing and promote germane processing as compared with narrated animations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Small-signal analysis of 1.3-μm microcavity light-emittingdiodes

The modulation speed of 1.3-μm microcavity light-emitting diodes (MCLEDs) has been measured using a small-signal modulation analysis. A speed of 260 MHz using a 25-μm diameter sample at current density of 10 kA/cm² has been achieved. The carrier confinement has been calculated for several carrier densities in order to investigate the origin of the speed limitation. By comparing the performance of the 1.3-μm MCLEDs with that of the 990-nm devices we conclude that the limiting factor on the speed seems to be a lack of carrier confinement in the quantum wells and not a cavity effect     

From genius inverts to gendered intelligence: Lewis Terman and the power of the norm.

The histories of "intelligence" and "sexuality" have largely been narrated separately. In Lewis Terman's work on individual differences, they intersect. Influenced by G. Stanley Hall, Terman initially described atypically accelerated development as problematic. Borrowing from Galton, Terman later positioned gifted children as nonaverage but ideal. Attention to the gifted effeminate subjects used to exemplify giftedness and gender nonconformity in Terman's work shows the selective instantiation of nonaverageness as pathological a propos of effeminacy, and as ideal a propos of high intelligence. Throughout, high intelligence is conflated with health, masculinity, and heterosexuality. Terman's research located marital sexual problems in women's bodies, further undoing possibilities for evaluating heterosexual men's practices as different from a normative position. Terman's research modernized Galton's imperialist vision of a society led by a male cognitive elite. Psychologists continue to traffic in his logic that values and inculcates intelligence only in the service of sexual and gender conformity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)