2,480 research outputs found
Symmetry breaking and quark-hadron duality in structure functions
We identify conditions under which a summation over nucleon resonances can
yield, via quark-hadron duality, parton model results for electromagnetic and
neutrino structure functions at large x. While a summation over the lowest even
and odd parity multiplets is sufficient to achieve duality in the symmetric
quark model, a suppression of transitions to specific final states is required
for more realistic cases incorporating SU(6) breaking. We outline several
scenarios consistent with duality, discuss their implications for the high Q^2
behavior of transition form factors, and illustrate how they can expose the
patterns in the flavor-spin dependence of inter-quark forces.Comment: 30 pages, 9 figures, to appear in Phys. Rev.
Participation and Performance on Paper- and Computer-Based Low-Stakes Assessments
High-stakes assessments, such the Graduate Records Examination, have
transitioned from paper to computer administration. Low-stakes Research-Based
Assessments (RBAs), such as the Force Concept Inventory, have only recently
begun this transition to computer administration with online services. These
online services can simplify administering, scoring, and interpreting
assessments, thereby reducing barriers to instructors' use of RBAs. By
supporting instructors' objective assessment of the efficacy of their courses,
these services can stimulate instructors to transform their courses to improve
student outcomes. We investigate the extent to which RBAs administered outside
of class with the online Learning About STEM Student Outcomes (LASSO) platform
provide equivalent data to tests administered on paper in class, in terms of
both student participation and performance. We use an experimental design to
investigate the differences between these two assessment conditions with 1,310
students in 25 sections of 3 college physics courses spanning 2 semesters.
Analysis conducted using Hierarchical Linear Models indicates that student
performance on low-stakes RBAs is equivalent for online (out-of-class) and
paper-and-pencil (in-class) administrations. The models also show differences
in participation rates across assessment conditions and student grades, but
that instructors can achieve participation rates with online assessments
equivalent to paper assessments by offering students credit for participating
and by providing multiple reminders to complete the assessment. We conclude
that online out-of-class administration of RBAs can save class and instructor
time while providing participation rates and performance results equivalent to
in-class paper-and-pencil tests
In-class vs. online administration of concept inventories and attitudinal assessments
This study investigates differences in student responses to in-class and
online administrations of the Force Concept Inventory (FCI), Conceptual Survey
of Electricity and Magnetism (CSEM), and the Colorado Learning Attitudes about
Science Survey (CLASS). Close to 700 physics students from 12 sections of three
different courses were instructed to complete the concept inventory relevant to
their course, either the FCI or CSEM, and the CLASS. Each student was randomly
assigned to take one of the surveys in class and the other survey online using
the LA Supported Student Outcomes (LASSO) system hosted by the Learning
Assistant Alliance (LAA). We examine how testing environments and instructor
practices affect participation rates and identify best practices for future
use.Comment: 4 pages, 3 tables, 3 figures, Physics Education Research Conference
proceeding
Elements of Proximal Formative Assessment in Learners’ Discourse about Energy
Proximal formative assessment, the just-in-time elicitation of students\u27 ideas that informs ongoing instruction, is usually associated with the instructor in a formal classroom setting. However, the elicitation, assessment, and subsequent instruction that characterize proximal formative assessment are also seen in discourse among peers. We present a case in which secondary teachers in a professional development course at SPU are discussing energy flow in refrigerators. In this episode, a peer is invited to share her thinking (elicitation). Her idea that refrigerators move heat from a relatively cold compartment to a hotter environment is inappropriately judged as incorrect (assessment). The instruction (peer explanation) that follows is based on the second law of thermodynamics, and acts as corrective rather than collaborative
Exercise redox biochemistry:conceptual, methodological and technical recommendations
Exercise redox biochemistry is of considerable interest owing to its translational value in health and disease. However, unaddressed conceptual, methodological and technical issues complicate attempts to unravel how exercise alters redox homeostasis in health and disease. Conceptual issues relate to misunderstandings that arise when the chemical heterogeneity of redox biology is disregarded which often complicate attempts to use redox-active compounds and assess redox signalling. Further, that oxidised macromolecule adduct levels reflect formation and repair is seldom considered. Methodological and technical issues relate to the use of out-dated assays and/or inappropriate sample preparation techniques that confound biochemical redox analysis. After considering each of the aforementioned issues, we outline how each issue can be resolved and provide a unifying set of recommendations. We specifically recommend that investigators: consider chemical heterogeneity, use redox-active compounds judiciously, abandon flawed assays, carefully prepare samples and assay buffers, consider repair/metabolism, use multiple biomarkers to assess oxidative damage and redox signalling
Occult Stories
Story titles: A Curious Experience; One Thanksgiving; The Colonel\u27s Story; We Shall Know Our Loved Ones; Hold On; Our Thoughts; Wait; Baby Bess
Radiative decays: a new flavour filter
Radiative decays of the orbital excitations of the ,
and to the scalars , and are shown to
provide a flavour filter, clarifying the extent of glueball mixing in the
scalar states. A complementary approach to the latter is provided by the
radiative decays of the scalar mesons to the ground-state vectors ,
and . Discrimination among different mixing scenarios is strong.Comment: 12 pages, 1 table, 0 figure
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