363 research outputs found
Using conceptual metaphor and functional grammar to explore how language used in physics affects student learning
This paper introduces a theory about the role of language in learning
physics. The theory is developed in the context of physics students' and
physicists' talking and writing about the subject of quantum mechanics. We
found that physicists' language encodes different varieties of analogical
models through the use of grammar and conceptual metaphor. We hypothesize that
students categorize concepts into ontological categories based on the
grammatical structure of physicists' language. We also hypothesize that
students over-extend and misapply conceptual metaphors in physicists' speech
and writing. Using our theory, we will show how, in some cases, we can explain
student difficulties in quantum mechanics as difficulties with language.Comment: Accepted for publication in Phys. Rev. ST:PE
Researching and Designing for the Orchestration of Learning in the CSCL Classroom
Designing tools for teachers to orchestrate computer supported collaborative learning activities in their classrooms requires that attention be paid to the range of roles and activities a teacher must take throughout the process. Drawing on the Implementing Collaborative Learning in the Classroom framework proposed by Kaendler, Wiedmann, Rummel and Spada (2014), the contributors to this symposium will speak to the way their designs address the various parts of this framework, allowing us to draw conclusions about what has been successful for different parts of this process, and identifying future directions for development and research
Strange Messages: Chemical and Thermal Freeze-out in Nuclear Collisions
Thermal models are commonly used to interpret heavy-ion data on particle
yields and spectra and to extract the conditions of chemical and thermal
freeze-out in heavy-ion collisions. I discuss the usefulness and limitations of
such thermal model analyses and review the experimental and theoretical
evidence for thermalization in nuclear collisions. The crucial role of
correlating strangeness production data with single particle spectra and
two-particle correlation measurements is pointed out. A consistent dynamical
picture for the heavy-ion data from the CERN SPS involves an initial
prehadronic stage with deconfined color and with an appreciable isotropic
pressure component. This requires an early onset of thermalization.Comment: 15 pages, 2 figures, talk given at Strange Quark Matter '98, Padova,
Italy, 20-24 July 1998, to be published in J. Phys. G 25; final version with
updated reference
Chemical equilibration of strangeness
Thermal models are very useful in the understanding of particle production in
general and especially in the case of strangeness. We summarize the assumptions
which go into a thermal model calculation and which differ in the application
of various groups. We compare the different results to each other. Using our
own calculation we discuss the validity of the thermal model and the amount of
strangeness equilibration at CERN-SPS energies. Finally the implications of the
thermal analysis on the reaction dynamics are discussed.Comment: 23 pages, LaTeX (figures included); Talk given at the Int. Symposium
on Strangeness in Quark Matter 1997, Santorini (Greece), April 199
Quantum radiation in external background fields
A canonical formalism is presented which allows for investigations of quantum
radiation induced by localized, smooth disturbances of classical background
fields by means of a perturbation theory approach. For massless,
non-selfinteracting quantum fields at zero temperature we demonstrate that the
low-energy part of the spectrum of created particles exhibits a non-thermal
character. Applied to QED in varying dielectrics the response theory approach
facilitates to study two distinct processes contributing to the production of
photons: the squeezing effect due to space-time varying properties of the
medium and of the velocity effect due to its motion. The generalization of this
approach to finite temperatures as well as the relation to sonoluminescence is
indicated.Comment: 20 page
PRIDE: Quality control in a proteomics data repository
The PRoteomics IDEntifications (PRIDE) database is a large public proteomics data repository, containing over 270 million mass spectra (by November 2011). PRIDE is an archival database, providing the proteomics data supporting specific scientific publications in a computationally accessible manner. While PRIDE faces rapid increases in data deposition size as well as number of depositions, the major challenge is to ensure a high quality of data depositions in the context of highly diverse proteomics work flows and data representations. Here, we describe the PRIDE curation pipeline and its practical application in quality control of complex data depositions
Histological assessment of paxgene tissue fixation and stabilization reagents
Within SPIDIA, an EC FP7 project aimed to improve pre analytic procedures, the PAXgene Tissue System (PAXgene), was designed to improve tissue quality for parallel molecular and morphological analysis. Within the SPIDIA project promising results were found in both genomic and proteomic experiments with PAXgene-fixed and paraffin embedded tissue derived biomolecules. But, for this technology to be accepted for use in both clinical and basic research, it is essential that its adequacy for preserving morphology and antigenicity is validated relative to formalin fixation. It is our aim to assess the suitability of PAXgene tissue fixation for (immuno)histological methods. Normal human tissue specimens (n = 70) were collected and divided into equal parts for fixation either with formalin or PAXgene. Sections of the obtained paraffin-embedded tissue were cut and stained. Morphological aspects of PAXgene-fixed tissue were described and also scored relative to formalin-fixed tissue. Performance of PAXgene-fixed tissue in immunohistochemical and in situ hybridization assays was also assessed relative to the corresponding formalin-fixed tissues. Morphology of PAXgene-fixed paraffin embedded tissue was well preserved and deemed adequate for diagnostics in most cases. Some antigens in PAXgene-fixed and paraffin embedded sections were detectable without the need for antigen retrieval, while others were detected using standard, formalin fixation based, immunohistochemistry protocols. Comparable results were obtained with in situ hybridization and histochemical stains. Basically all assessed histological techniques were found to be applicable to PAXgene-fixed and paraffin embedded tissue. In general results obtained with PAXgene-fixed tissue are comparable to those of formalin-fixed tissue. Compromises made in morphology can be called minor compared to the advantages in the molecular pathology possibilities
An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics
For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
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