2,393 research outputs found

    Schools in Balance: Comparing Iowa Physics Teachers and Teaching in Large and Small Schools

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    In 2009 we surveyed all known Iowa high school physics teachers to gain insight into their educational backgrounds, instructional styles, content coverage, and available resources. Based upon a suggestion made at a subsequent presentation, we reexamined the collected data, comparing the responses of teachers from small and large schools to see if there were notable differences between the two populations. We found that teachers at larger schools teach a wider variety of physics courses, including more advanced and “physics first” style courses, and report stronger educational backgrounds in physics. While larger schools also have more financial resources allocated for physics teaching, the larger enrollments in physics courses at these schools means there is roughly the same amount of available money per student at all schools

    Addressing student models of energy loss in quantum tunnelling

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    We report on a multi-year, multi-institution study to investigate student reasoning about energy in the context of quantum tunnelling. We use ungraded surveys, graded examination questions, individual clinical interviews, and multiple-choice exams to build a picture of the types of responses that students typically give. We find that two descriptions of tunnelling through a square barrier are particularly common. Students often state that tunnelling particles lose energy while tunnelling. When sketching wave functions, students also show a shift in the axis of oscillation, as if the height of the axis of oscillation indicated the energy of the particle. We find inconsistencies between students' conceptual, mathematical, and graphical models of quantum tunnelling. As part of a curriculum in quantum physics, we have developed instructional materials to help students develop a more robust and less inconsistent picture of tunnelling, and present data suggesting that we have succeeded in doing so.Comment: Originally submitted to the European Journal of Physics on 2005 Feb 10. Pages: 14. References: 11. Figures: 9. Tables: 1. Resubmitted May 18 with revisions that include an appendix with the curriculum materials discussed in the paper (4 page small group UW-style tutorial

    Comments on the distribution of \u3ci\u3eBotrychium lunarioides\u3c/i\u3e (Ophioglossaceae) in Texas

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    Botrychium lunarioides (Michx.) Sw. (Ophioglossaceae) is now known to be widespread and abundant throughout the eastern portion of Texas. In 1996, Do, et al. reported ten additional county records in the central portion of the Post Oak Savannah of Texas, thereby extending the known distribution of the species up to 273 km to the west. Additional field studies during 1996 have yielded nineteen new county records for the species in Texas. These new reports are primarily from the Post Oak Savannah, Pineywoods, and Blackland Prairies of northeast Texas and from the southern portion of the Post Oak Savannah. The most notable occurrence of the species is at Lake Bastrop State Recreation Area, Bastrop County, about 45 km ESE of Austin, which extends both the western and southern known limits of the species

    Isolation of Escherichia coli O157:H7 from Intact Colon Fecal Samples of Swine1

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    Escherichia coli O157:H7 was recovered from colon fecal samples of pigs. Polymerase chain reaction confirmed two genotypes: isolates harboring the eaeA, stx1, and stx2 genes and isolates harboring the eaeA, stx1, and hly933 genes. We demonstrate that swine in the United States can harbor potentially pathogenic E. coli O157:H7

    The Design and Validation of the Quantum Mechanics Conceptual Survey

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    The Quantum Mechanics Conceptual Survey (QMCS) is a 12-question survey of students' conceptual understanding of quantum mechanics. It is intended to be used to measure the relative effectiveness of different instructional methods in modern physics courses. In this paper we describe the design and validation of the survey, a process that included observations of students, a review of previous literature and textbooks and syllabi, faculty and student interviews, and statistical analysis. We also discuss issues in the development of specific questions, which may be useful both for instructors who wish to use the QMCS in their classes and for researchers who wish to conduct further research of student understanding of quantum mechanics. The QMCS has been most thoroughly tested in, and is most appropriate for assessment of (as a posttest only), sophomore-level modern physics courses. We also describe testing with students in junior quantum courses and graduate quantum courses, from which we conclude that the QMCS may be appropriate for assessing junior quantum courses, but is not appropriate for assessing graduate courses. One surprising result of our faculty interviews is a lack of faculty consensus on what topics should be taught in modern physics, which has made designing a test that is valued by a majority of physics faculty more difficult than expected.Comment: Submitted to Physical Review Special Topics: Physics Education Researc

    Development of a Novel miR-3648-Related Gene Signature as a Prognostic Biomarker in Esophageal Adenocarcinoma

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    Background: Esophageal adenocarcinoma (EA) is a typical immunogenic malignant tumor with a dismal 5-year survival rate lower than 20%. Although miRNA-3648 (miR-3648) is expressed abnormally in EA, its impact on the tumor immune microenvironment remains unknown. In this study, we sought to identify immune-related genes (IRGs) that are targeted by miR-3648 and develop an EA multigene signature. Methods: The gene expression data of 87 EA tumor samples and 67 normal tissue samples from The Cancer Genome Atlas (TCGA) database and the Genotype-Tissue Expression (GTEx) database were downloaded, respectively. Weighted gene co-expression network analysis (WGCNA), the CIBERSORT algorithm, and Cox regression analysis were applied to identify IRGs and to construct a prognostic signature and nomogram. Results: MiR-3648 was expectedly highly expressed in EA tumor tissues (P=2.6e-8), and related to the infiltration of activated natural killer cells (NK cells) and activated CD4 T lymphocytes (CD4 cells). A total of 70 miR-3648-targeted genes related to immune cell infiltration were identified. Among them, 4 genes (C10orf55, DLL4, PANX2, and NKAIN1) were closely related to overall survival (OS), and were thus selected to construct a 4-gene risk score (RS). The RS had a superior capability to predict OS [area under the curve (AUC) =0.740 for 1 year; AUC =0.717 for 3 years; AUC =0.622 for 5 years]. A higher score was indicative of a poorer prognosis than a lower score [hazard ratio (HR) =2.71; 95% confidence interval (CI): 1.45–5.09; P=0.002]. Furthermore, the nomogram formed by combining the RS and the TNM classification of malignant tumors (TNM stage) improved the accuracy of survival prediction [Harrell’s concordance index (C-index) =0.698]. Conclusions: MiR-3648 may play a critical role in EA pathogenesis. The novel 4-gene signature may serve as a prognostic tool to manage patients with EA

    Wild Turkey Responses to Forest Management

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    To better understand the response of wild turkeys to forest management activities and black flies, the objectives of Segment 5 of the Wild Turkey Responses to Forest Management research project were to: 1) Continue radio-tracking Wild Turkeys captured during the previous segment and capture and affix radios to up to an additional 40 hens enhance sample sizes across study sites; 2) Use micro-GPS telemetry to examine the effects of forest management, habitat and landscape features, and black flies on Wild Turkey habitat use, survival and reproductive success, emphasizing central and western Illinois sites; 3) Use micro-GPS telemetry, accelerometer data, and insect surveys during the breeding season to document potential effects of black flies on hen turkey incubation behavior, hen and nest mortality, and possibly poult survival; 4) Submit at least one manuscript for publication in a peer-reviewed journal and provide one popular article about this project to the Illinois Department of Natural Resources by the grant end date (popular article will be approximately 500 words in length with at least two pictures provided).Illinois Department of Natural Resources Division of Wildlifeunpublishednot peer reviewedOpe

    Synthesis, Characterization, and Direct Intracellular Imaging of Ultrasmall and Uniform Glutathione‐Coated Gold Nanoparticles

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    Gold nanoparticles (AuNPs) with core sizes below 2 nm and compact ligand shells constitute versatile platforms for the development of novel reagents in nanomedicine. Due to their ultrasmall size, these AuNPs are especially attractive in applications requiring delivery to crowded intracellular spaces in the cytosol and nucleus. For eventual use in vivo, ultrasmall AuNPs should ideally be monodisperse, since small variations in size may affect how they interact with cells and how they behave in the body. Here we report the synthesis of ultrasmall, uniform 144‐atom AuNPs protected by p ‐mercaptobenzoic acid followed by ligand exchange with glutathione (GSH). Quantitative scanning transmission electron microscopy (STEM) reveals that the resulting GSH‐coated nanoparticles (Au(GSH)) have a uniform mass distribution with cores that contain 134 gold atoms on average. Particle size dispersity is analyzed by analytical ultracentrifugation, giving a narrow distribution of apparent hydrodynamic diameter of 4.0 ± 0.6 nm. To evaluate the nanoparticles’ intracellular fate, the cell‐penetrating peptide TAT is attached noncovalently to Au(GSH), which is confirmed by fluorescence quenching and isothermal titration calorimetry. HeLa cells are then incubated with both Au(GSH) and the Au(GSH)‐TAT complex, and imaged without silver enhancement of the AuNPs in unstained thin sections by STEM. This imaging approach enables unbiased detection and quantification of individual ultrasmall nanoparticles and aggregates in the cytoplasm and nucleus of the cells. The synthesis and characterization of an ultrasmall and uniform glutathione‐coated gold nanoparticle is reported. It is also shown that scanning transmission electron microscopy (STEM) enables the visualization and quantification of individual gold nanoparticles as well as small aggregates in the cytoplasm and nucleus of HeLa cells.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92372/1/2277_ftp.pd
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