Microcomputers and the Preparation of Secondary Science Teachers: An Eight Year Follow-Up

Science teacher educators from 205 colleges/universities completed a questionnaire concerning the nature and extent of microcomputer offerings in their secondary science teacher preparation programs. These data are reported and compared to a similar sample surveyed in 1984. Seventy-seven percent of reporting institutions now require either a microcomputer course or completion of a microcomputer competency within their secondary science certification program. The most common applications in these courses are simulations, word processing, databases, and spreadsheet use. Chi-square analysis revealed that more institutions in 1992 were requiring a microcomputer course than in 1984. However, only 23.4% of the institutions offered a microcomputer course designed solely for secondary science majors, and 10.6% of the institutions offered such a course taught by a science teacher educator. Preservice science teachers were also more likely in 1992 than in 1984 to be using microcomputers in instruction during supervised field experiences in secondary schools. Finally, college/university science teacher educators perceived that microcomputer use in secondary science classrooms has increased during the past five years.     

Recycling of Informational Units Leads to Selection of Replicators in a Prebiotic Soup

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Highlights? Recycling of genetic material is important for the origins of life ? Simulation studies show recycling leads to the selection of genotypes from a pool ? Recycling can lead to the sudden emergence of a high-fitness RNA genotype ? Experimental studies with the Azoarcus ribozyme show fragment recycling     

Alpha-deuteron structure of 6Li as predicted by a separable-potential three-body model

Schroedinger's equation with separable n-p (³S₁) and $\text{n}\text{-α (}{}^2\text{P}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{)}$ potentials solved to obtain a three-body model of the ⁶Li ground-state wave function. This model predicts the α-n-p binding energy of ⁶Li to be 4.67 MeV [Exp.: 4.53 MeV = 3.697 + 0.834 (Coulomb)], the asymptotic normalization constant of the d-α tail to be 2.39, and the amount of d+α component to be 65%. The ⁶Li→α+d vertex function is slightly more momentum dependent than present experiments suggest.     

Testing Monotonicity

at arguments of its choice, the test always accepts a monotone f, and rejects f with high probability if it is ε-far from being monotone (i.e., every monotone function differs from f on more than an ε fraction of the domain). The complexity of the test is O(n/ε). The analysis of our algorithm relates two natural combinatorial quantities that can be measured with respect to a Boolean function; one being global to the function and the other being local to it. A key ingredient is the use of a switching (or sorting) operator on functions. Received March 29, 1999     

Visual spatial memory is enhanced in female rats (but inhibited in males) by dietary soy phytoestrogens

Background  

In learning and memory tasks, requiring visual spatial memory (VSM), males exhibit superior performance to females (a difference attributed to the hormonal influence of estrogen). This study examined the influence of phytoestrogens (estrogen-like plant compounds) on VSM, utilizing radial arm-maze methods to examine varying aspects of memory. Additionally, brain phytoestrogen, calbindin (CALB), and cyclooxygenase-2 (COX-2) levels were determined.     

Diffusion-weighted MRI: influence of intravoxel fat signal and breast density on breast tumor conspicuity and apparent diffusion coefficient measurements

Promising recent investigations have shown that breast malignancies exhibit restricted diffusion on diffusion-weighted imaging (DWI) and may be distinguished from normal tissue and benign lesions in the breast based on differences in apparent diffusion coefficient (ADC) values. In this study, we assessed the influence of intravoxel fat signal on breast diffusion measures by comparing ADC values obtained using a diffusion-weighted single shot fast spin-echo sequence with and without fat suppression. The influence of breast density on ADC measures was also evaluated. ADC values were calculated for both tumor and normal fibroglandular tissue in a group of 21 women with diagnosed breast cancer. There were systematic underestimations of ADC for both tumor and normal breast tissue due to intravoxel contribution from fat signal on non–fat-suppressed DWI. This ADC underestimation was more pronounced for normal tissue values (mean difference=40%) than for tumors (mean difference=27%, P<.001) and was worse in women with low breast tissue density vs. those with extremely dense breasts (P<.05 for both tumor and normal tissue). Tumor conspicuity measured by contrast-to-noise ratio was significantly higher on ADC maps created with fat suppression and was not significantly associated with breast density. In summary, robust fat suppression is important for accurate breast ADC measures and optimal lesion conspicuity on DWI.     

Secondary Science Teachers' Use of Microcomputers During Instruction

One hundred seventy-nine secondary science department chairs answered a 20-item questionnaire concerning the nature and extent of microcomputer use in science instruction in their respective schools. The national sample represented schools in rural, urban, and suburban settings, as well as all geographic regions of the country. Analyses of data revealed that 47% of the secondary science teachers did not use microcomputers during instruction, 40% used them occasionally, and 13% used them in one or more lessons each week. The most frequent applications were simulations (70%), graphing packages (63%), and probes for collecting laboratory data (56%). In addition, 76% of the respondents indicated that microcomputers have had an impact on science laboratory activities in their schools. The department chairs also listed their perceived reasons as to why teachers in their departments did or did not integrate microcomputer use into their science instruction.     

Technology Use in the Teaching of Mathematics and Science in Elementary Schools

Principals from 80 elementary schools, in predominantly rural Western Pennsylvania, completed and returned a 22-item questionnaire designed to assess the nature and extent of technology use for the teaching of elementary mathematics and science within their buildings. Technologies included calculators, microcomputers, overhead projection panels, videotape, and interactive video. Microcomputers were being used in at least some elementary grade levels for mathematics or science instruction in 84% of the schools. Teachers used microcomputers more frequently in mathematics (82.5%) than in science instruction (55%). Principals reported a lower frequency of calculator use with 63.3% of the schools having some grade levels where calculators were used in mathematics lessons, and 21.5% of schools in science lessons. Further analyses of data suggest that microcomputer and calculator use is more common in the intermediate grades (3–6) than in the primary grades (K-2).     

Integrating Science and Mathematics: Perceptions of Preservice and Practicing Elementary Teachers

One hundred and sixty-one undergraduate elementary education majors and sixty elementary teachers completed an eight-item questionnaire designed to assess their perceptions toward integrating science and mathematics in the elementary grades. The two groups of subjects differed significantly on their responses to five of the eight items. Chi square analyses suggest that practicing elementary teachers felt they had more background in mathematics and science, were more aware of curriculum materials in this area, did not think that integration was currently a common practice, and were more likely to indicate that there was not sufficient time in the school day to integrate the subjects. Preservice teachers were more likely to indicate that integrating the disciplines was preferred to teaching them separately. In addition to the analyses of data, a list of recommendations are provided for teachers, curriculum developers, and policy makers interested in advancing the concept of integrating science and mathematics in instruction.