Can one written word mean many things? Prereaders’ assumptions about the stability of written words’ meanings

Results of three experiments confirmed previous findings that in a moving word task, prereaders 3 to 5 years of age judge as if the meaning of a written word changes when it moves from a matching to a nonmatching toy (e.g., when the word “dog” moves from a dog to a boat). We explore under what circumstances children make such errors, we identify new conditions under which children were more likely correctly to treat written words’ meanings as stable: when the word was placed alongside a nonmatching toy without having been alongside a matching toy previously, when two words were moved from a matching toy to a nonmatching toy, and when children were asked to change what the print said. Under these conditions, children more frequently assumed that physical forms had stable meanings as they do with other forms of external representation

Contracting Away Success: The Way Teacher Collective Bargaining Agreements Are Undermining the Education of America's Children

While American public education once stood as an example of educational excellence globally, it now exists as only a shell of what it once was. Students from countries across the globe now routinely outperform American children and as each year passes, students filling classrooms in the United States slip farther and farther behind their international peers. American student proficiency rates across all subject areas sit at such low levels that they call into serious the question the creation of a competent and efficient workforce prepared to address and correct the varied problems the nation faces as it begins the 21st century. While numerous factors have contributed to this eroding of American education, one factor of significant influence is the practice of collective bargaining by teachers' unions with school districts, as it exists today. Though unions and collective bargaining serve an important role in American public education, protecting the interests of teachers and ensuring fair employment standards for these professionals, many aspects of these agreements between unions and school districts give short shrift to their negative implications for the students these teachers hope to educate. The goal of this Note is to demonstrate the negative effects collective bargaining has had and continues to have on student achievement in America's public schools, flesh out the problematic areas within these agreements, and put forth suggestions as to how the practice of collective bargaining might be modified to better serve American children, those on whom the public education should be principally focused

Domestic dogs' (Canis familiaris) understanding of Projected Video Images of a Human Demonstrator in an Object-choice Task

Presenting animals with artificial visual stimuli is a key element of many recent behavioral experiments largely because images are easier to control and manipulate than live demonstrations. Determining how animals process images is crucial for being able to correctly interpret subjects' reactions toward these stimuli. In this study, we aimed to use the framework proposed by Fagot etal. (2010) Proc. Natl. Acad. Sci. USA 107, 519 to classify how dogs perceive life-sized projected videos. First, we tested whether dogs can use pre-recorded and hence non-interactive, video footage of a human to locate a hidden reward in a three-way choice task. Secondly, we investigated whether dogs solve this task by means of referential understanding. To achieve this, we separated the location of the video projection from the location where dogs had to search for the hidden reward. Our results confirmed that dogs can reliably use pre-recorded videos of a human as a source of information when the demonstration and the hiding locations are in the same room. However, they did not find the hidden object above the chance level when the hiding locations were in a separate room. Still, further analysis found a positive connection between the attention paid to the projection and the success rate of dogs. This finding suggests that the factor limiting dogs' performance was their attention and that with further training they might be able to master tasks involving referential understanding

Selection of chromosomal DNA libraries using a multiplex CRISPR system.

The directed evolution of biomolecules to improve or change their activity is central to many engineering and synthetic biology efforts. However, selecting improved variants from gene libraries in living cells requires plasmid expression systems that suffer from variable copy number effects, or the use of complex marker-dependent chromosomal integration strategies. We developed quantitative gene assembly and DNA library insertion into the Saccharomyces cerevisiae genome by optimizing an efficient single-step and marker-free genome editing system using CRISPR-Cas9. With this Multiplex CRISPR (CRISPRm) system, we selected an improved cellobiose utilization pathway in diploid yeast in a single round of mutagenesis and selection, which increased cellobiose fermentation rates by over 10-fold. Mutations recovered in the best cellodextrin transporters reveal synergy between substrate binding and transporter dynamics, and demonstrate the power of CRISPRm to accelerate selection experiments and discoveries of the molecular determinants that enhance biomolecule function

It Works Both Ways: Transfer Difficulties between Manipulatives and Written Subtraction Solutions

Three experiments compared performance and transfer among children aged 83-94 months after written or manipulatives instruction on two-digit subtraction. In Experiment 1, all children completed the posttest in a written format, while in Experiment 2, all children took a posttest using manipulatives. Experiment 3 investigated how altered surface features of the blocks affected posttest performance, subtraction strategies and mathematical behaviors. In the first two experiments, children demonstrated performance gains when the posttest format was identical to the instructed format, but failed to demonstrate transfer from the instructed format to an incongruent posttest. Posttest performance in these two experiments provides evidence for bidirectional challenges in transfer between manipulatives and written instruction. In the third experiment, children who learned with standard, unaltered blocks more often used productive problem-solving strategies and engaged in mathematical behaviors significantly more often than children who used blocks with altered surface features. Flexibility and the need to provide explicit links between written and manipulatives instruction are discussed.Fil: David, Uttal H.. Northwestern University; Estados UnidosFil: Amaya, Meredith. Northwestern University; Estados UnidosFil: Maita, María del Rosario. Northwestern University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto Rosario de Investigaciones en Ciencias de la Educación; ArgentinaFil: Liu Hand, Linda. Northwestern University; Estados Unidos. University of Iowa; Estados UnidosFil: Cohen, Cheryl. Northwestern University; Estados UnidosFil: O'Doherty, Katherine. Vanderbilt University; Estados UnidosFil: Deloache, Judy. University of Virginia; Estados Unido

Size and emotion or depth and emotion? Evidence, using Matryoshka (Russian) dolls, of children using physical depth as a proxy for emotional charge

Background: The size and emotion effect is the tendency for children to draw people and other objects with a positive emotional charge larger than those with a negative or neutral charge. Here we explored the novel idea that drawing size might be acting as a proxy for depth (proximity).Methods: Forty-two children (aged 3-11 years) chose, from 2 sets of Matryoshka (Russian) dolls, a doll to represent a person with positive, negative or neutral charge, which they placed in front of themselves on a sheet of A3 paper. Results: We found that the children used proximity and doll size, to indicate emotional charge. Conclusions: These findings are consistent with the notion that in drawings, children are using size as a proxy for physical closeness (proximity), as they attempt with varying success to put positive charged items closer to, or negative and neutral charge items further away from, themselves