Physics

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected].

To test whether epistemically unproblematic ways of thinking and talking about science could be transformed during preservice teacher training, we designed a system of learning activities based on a set of heuristics for progressive disciplinary discourse (HPDD). The HPDD outline six design principles of learning environments where the aim is to foster learners' participation in material and discursive activities that characterize the work of scientists. After tracking participants through university coursework where the HPDD was employed and into their teaching practicums, we found that most came to reconceptualize the interrelated roles of models, theory, evidence, and argument. These ideas ultimately supported a shift in their goals for scientific investigation-from "proving" a hypothesis, to testing and revising explanatory models. Preliminary findings from teaching episodes with their own secondary students indicated that some participants took up "epistemically ambitious" classroom practices, pressing learners to develop testable models of natural phenomena and gather evidence to link observations with underlying explanatory processes.

One hundred years after its conception, the scientific method continues to reinforce a kind of cultural lore about what it means to participate in inquiry. As commonly implemented in venues ranging from middle school classrooms to undergraduate laboratories, it emphasizes the testing of predictions rather than ideas, focuses learners on material activity at the expense of deep subject matter understanding, and lacks epistemic framing relevant to the discipline. While critiques of the scientific method are not new, its cumulative effects on learners' conceptions of science have not been clearly articulated. We discuss these effects using findings from a series of five studies with degree-holding graduates of our educational system who were preparing to enter the teaching profession and apprentice their own young learners into unproblematic images of how science is done. We then offer an alternative vision for investigative science-model-based inquiry (MBI)as a system of activity and discourse that engages learners more deeply with content and embodies five epistemic characteristics of scientific knowledge: that ideas represented in the form of models are testable, revisable, explanatory, conjectural, and generative. We represent MBI as an interconnected set of classroom conversations and provide examples of its implementation and its limitations.

Expert-like instructional practice is commonly assumed to be achievable only after years of classroom experience. This study tested the hypothesis that novices in their first year of teaching could take up forms of ambitious pedagogy under the following conditions: that a defined set of reform-based pedagogical practices introduced in teacher preparation would be the focus of sustained self-inquiry throughout the first year of teaching, that participants use the analysis of their own pupils' work as the basis of critique and change in practice, and that special tools be employed that help participants use a common frame of reference for hypothesizing about relationships between instructional decisions and student performance.

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected].

One hundred years after its conception, the scientific method continues to reinforce a kind of cultural lore about what it means to participate in inquiry. As commonly implemented in venues ranging from middle school classrooms to undergraduate laboratories, it emphasizes the testing of predictions rather than ideas, focuses learners on material activity at the expense of deep subject matter understanding, and lacks epistemic framing relevant to the discipline. While critiques of the scientific method are not new, its cumulative effects on learners' conceptions of science have not been clearly articulated. We discuss these effects using findings from a series of five studies with degree-holding graduates of our educational system who were preparing to enter the teaching profession and apprentice their own young learners into unproblematic images of how science is done. We then offer an alternative vision for investigative science-model-based inquiry (MBI)as a system of activity and discourse that engages learners more deeply with content and embodies five epistemic characteristics of scientific knowledge: that ideas represented in the form of models are testable, revisable, explanatory, conjectural, and generative. We represent MBI as an interconnected set of classroom conversations and provide examples of its implementation and its limitations.

Expert-like instructional practice is commonly assumed to be achievable only after years of classroom experience. This study tested the hypothesis that novices in their first year of teaching could take up forms of ambitious pedagogy under the following conditions: that a defined set of reform-based pedagogical practices introduced in teacher preparation would be the focus of sustained self-inquiry throughout the first year of teaching, that participants use the analysis of their own pupils' work as the basis of critique and change in practice, and that special tools be employed that help participants use a common frame of reference for hypothesizing about relationships between instructional decisions and student performance.

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected].

To test whether epistemically unproblematic ways of thinking and talking about science could be transformed during preservice teacher training, we designed a system of learning activities based on a set of heuristics for progressive disciplinary discourse (HPDD). The HPDD outline six design principles of learning environments where the aim is to foster learners' participation in material and discursive activities that characterize the work of scientists. After tracking participants through university coursework where the HPDD was employed and into their teaching practicums, we found that most came to reconceptualize the interrelated roles of models, theory, evidence, and argument. These ideas ultimately supported a shift in their goals for scientific investigation-from "proving" a hypothesis, to testing and revising explanatory models. Preliminary findings from teaching episodes with their own secondary students indicated that some participants took up "epistemically ambitious" classroom practices, pressing learners to develop testable models of natural phenomena and gather evidence to link observations with underlying explanatory processes.

One hundred years after its conception, the scientific method continues to reinforce a kind of cultural lore about what it means to participate in inquiry. As commonly implemented in venues ranging from middle school classrooms to undergraduate laboratories, it emphasizes the testing of predictions rather than ideas, focuses learners on material activity at the expense of deep subject matter understanding, and lacks epistemic framing relevant to the discipline. While critiques of the scientific method are not new, its cumulative effects on learners' conceptions of science have not been clearly articulated. We discuss these effects using findings from a series of five studies with degree-holding graduates of our educational system who were preparing to enter the teaching profession and apprentice their own young learners into unproblematic images of how science is done. We then offer an alternative vision for investigative science-model-based inquiry (MBI)as a system of activity and discourse that engages learners more deeply with content and embodies five epistemic characteristics of scientific knowledge: that ideas represented in the form of models are testable, revisable, explanatory, conjectural, and generative. We represent MBI as an interconnected set of classroom conversations and provide examples of its implementation and its limitations.

Expert-like instructional practice is commonly assumed to be achievable only after years of classroom experience. This study tested the hypothesis that novices in their first year of teaching could take up forms of ambitious pedagogy under the following conditions: that a defined set of reform-based pedagogical practices introduced in teacher preparation would be the focus of sustained self-inquiry throughout the first year of teaching, that participants use the analysis of their own pupils' work as the basis of critique and change in practice, and that special tools be employed that help participants use a common frame of reference for hypothesizing about relationships between instructional decisions and student performance.

Background The inbred long-sleep (ILS) and inbred short-sleep (ISS) strains of mice are widely studied as a model of initial sensitivity to alcohol. Recently, a large comparative DNA sequencing study of candidate genes located within the four Lore quantitative trait loci (QTLs) associated with the ethanol-induced loss of righting reflex in ILS and ISS mice has identified eight genes that contain coding region differences corresponding to amino acid changes. Here, recently developed interval-specific congenic recombinant mice (ISCRs) have been used to map these genes in relationship to newly narrowed QTL regions.Methods Regions of candidate genes containing DNA differences corresponding to previously identified amino acid changes between ISS and ILS mice were amplified from either genomic DNA or complementary DNA from ISCR mice using polymerase chain reaction. The products were purified and directly sequenced to determine the genotypes for each polymorphism. On the basis of these genotypic data, each candidate gene was determined to be located either within or outside of recently narrowed Lore QTL intervals.Results Of these eight candidates with protein-coding differences, five are now excluded from their respective Lore intervals. The other three (Znf142, Ptprn, and Znf133) have been localized to the narrowed QTL intervals.Conclusions These three central nervous system genes (Znf142, Ptprn, and Znf133) represent promising candidates for involvement in the differential sensitivity to alcohol exhibited between ILS and ISS mice. This study also demonstrates how the combination of high-throughput comparative gene sequencing and concomitant genetic fine mapping of QTL regions with ISCRs can be an effective tool for accelerating the process of moving from QTL to gene.

Low initial response to alcohol has been shown to be among the best predictors of development of alcoholism. A similar phenotypic measure, difference in initial sensitivity to ethanol, has been used for the genetic selection of two mouse strains, the Inbred Long-Sleep (ILS) and Inbred Short-Sleep (ISS) mice, and for the subsequent identification of four quantitative trait loci (QTLs) for alcohol sensitivity. We now report the application of high throughput comparative gene sequencing in the search for genes underlying these four QTLs. To carry out this search, over 1.7 million bases of comparative DNA sequence were generated from 68 candidate genes within the QTL intervals, corresponding to a survey of over 36,000 amino acids. Eight central nervous system genes, located within these QTLs, were identified that contain a total of 36 changes in protein coding sequence. Some of these coding variants are likely to contribute to the phenotypic variation between ILS/ISS animals, including sensitivity to alcohol, providing specific new genetic targets potentially important to the neuronal actions of alcohol.

Optically Stimulated Luminescence dating, grain-size analysis and magnetic susceptibility measurements were conducted on the Fanjiaping loess section, from the western Chinese Loess Plateau. The results confirm that last glacial high-frequency climatic shifts were documented in mid-latitude continental archives. The grain-size record indicated that coarse-grained sediments with horizontal bedding and channel-fill structures were only deposited in several short intervals, equivalent to the beginning of marine oxygen isotope stage (MIS) 4 and the early to middle MIS 3. This probably implies brief rainfall intensification of the Asian summer monsoon, and its disappearance since the late MIS 3 to MIS 2 may have been a response to significant glacial cooling in the Northern Hemisphere. Previous investigations revealed high sea-surface temperatures at high latitudes at the start of MIS 4, and the early to middle MIS 3 intensification of summer insolation in the Northern Hemisphere, implying evident climate amelioration. Climate improvement favors boreal forest recovery, enhancing both winter and summer air temperatures. The resultant smaller equatorpolar temperature gradient probably helped the moisture-laden summer monsoon to penetrate northward. This study thus provides new significant information about the response of terrestrial loessic palaeoenvironments to millennial-timescale climatic fluctuations during the last glacial period.

The macro- and microphysical properties of clouds can reflect their vertical physical structure and evolution and are important indications of the formation and development of precipitation. We used four-year merged CloudSat-CALIPSO-MODIS products to distinguish the macro- and microphysical properties of precipitating and non-precipitating clouds over central-eastern China during the warm season (May–September). Our results showed that the clouds were dominated by single- and double-layer forms with occurrence frequencies > 85%. Clouds with a low probability of precipitation (POP) were usually geometrically thin. The POP showed an increasing trend with increases in the cloud optical depth, liquid water path, and ice water path, reaching maxima of 50%, 60%, and 75%, respectively. However, as cloud effective radius (CER) increased, the POP changed from an increasing to a decreasing trend for a CER > 22 μm, in contrast with our perception that large particles fall more easily aga...

We have developed an atomic force microscopy ͑AFM͒ technique that can perform simultaneous normal and shear stiffness measurements of nanoconfined liquids with angstrom-range amplitudes. The AFM technique is based on a fiber-interferometric, small-amplitude, off-resonance AFM. This AFM is capable of providing linear quasistatic measurements of the local mechanical properties of confined liquid layers while only minimally disturbing the layers themselves. A detailed analysis of the measurement geometry reveals that shear stiffness measurements are extremely challenging, as even small deviations from perfect orthogonality can lead to data that is very difficult to interpret. We will show ways out of this dilemma and present results that show simultaneous measurement of the shear and normal stiffness of confined liquid layers.

This work is devoted to development of techniques for detection of adhesive in joints and image construction of the adhesive spatial distribution. Based on numerical modeling, the specific behavior of the reverberating pulseecho waveforms in steel–adhesive and aluminum–adhesive multi–layered structures is analyzed. It is shown that the energy of the received waveform weighted within a certain time gate can be used as a metric for discriminating between no/adhesive areas. To generate the image of the adhesive distribution the waveforms received by the elements of the matrix ultrasonic array were independently processed and the outputs are spatially interpolated and compared with a certain threshold. The developed algorithms have been tested on steel-to-steel, aluminum-toaluminum and aluminum-to-steel adhesive joints using 15 MHz, 52-element, 10 mm x 10 mm matrix array of ultrasonic transducers.