1,270 research outputs found
Online and Face-to-Face Classes: A Comparative Analysis of Teaching Presence and Instructor Satisfaction
Teaching presence is one of three components of the Community of Inquiry Model proposed by Garrison, Anderson, and Archer (2000). This study examined teaching presence, as measured by the instructional design and organization, and directed facilitation (Shea, Li, Swan, and Pickett, 2005), in a large undergraduate science course, contrasting two modes of lecture delivery, face-to-face and online video. Confirmatory factor analysis validated the teaching presence instrument, producing factor loadings similar to Shea et al.\u27s for both online and face-to-face delivery. Analysis of the relationship between instructor satisfaction and teaching presence (instructional design and organization, and directed facilitation) produced a significant (p \u3c 0.05) but relatively weak (r = .50) correlation. Differences between mean instructor satisfaction and teaching presence scores showed no significant differences based on the mode of lecture delivery. Advisor: Allen Steckelber
Medium modifications of nucleon electromagnetic form factors
We use the Nambu-Jona-Lasinio model as an effective quark theory to
investigate the medium modifications of the nucleon electromagnetic form
factors. By using the equation of state of nuclear matter derived in this
model, we discuss the results based on the naive quark-scalar diquark picture,
the effects of finite diquark size, and the meson cloud around the constituent
quarks. We apply this description to the longitudinal response function for
quasielastic electron scattering. RPA correlations, based on the
nucleon-nucleon interaction derived in the same model, are also taken into
account in the calculation of the response function.Comment: 46 pages, 16 figure
Effects of charge symmetry breaking on form factors of the pion and kaon
Effects of charge symmetry breaking associated with the and quark
mass difference in the elastic form factors of the pion and kaon are presented.
We use a confining version of the Nambu--Jona-Lasinio model. The pion and kaon
are described as a dressed quark and antiquark bound states governed by the
Bethe-Salpeter equation, and exhibit the properties of Goldstone bosons, with
the pion mass difference given by as demanded by dynamical chiral symmetry breaking. We found
significant charge symmetry breaking effects for realistic current quark mass
ratios () in the quark electromagnetic form factors of the
pion and kaon. We also report the effects of charge symmetry breaking on the
parton distribution functions, which are rather smaller than those found in the
electromagnetic form factors.Comment: 4 pages, 5 figures, accepted version for the QNP2018 proceedings, 8th
International Conference on Quarks and Nuclear Physics (QNP2018), November
13-17, 2018, Tsukuba, Ibaraki, Japa
A reaction-diffusion model for the hydration/setting of cement
We propose a heterogeneous reaction-diffusion model for the hydration and
setting of cement. The model is based on diffusional ion transport and on
cement specific chemical dissolution/precipitation reactions under spatial
heterogeneous solid/liquid conditions. We simulate the spatial and temporal
evolution of precipitated micro structures starting from initial random
configurations of anhydrous cement particles. Though the simulations have been
performed for two dimensional systems, we are able to reproduce qualitatively
basic features of the cement hydration problem. The proposed model is also
applicable to general water/mineral systems.Comment: REVTeX (12 pages), 4 postscript figures, tarred, gzipped, uuencoded
using `uufiles', coming with separate file(s). Figure 1 consists of 6 color
plates; if you have no color printer try to send it to a black&white
postscript-plotte
The NJL-jet model for quark fragmentation functions
A description of fragmentation functions which satisfy the momentum and
isospin sum rules is presented in an effective quark theory. Concentrating on
the pion fragmentation function, we first explain why the elementary (lowest
order) fragmentation process q --> q \pi is completely inadequate to describe
the empirical data, although the "crossed" process \pi --> q \bar{q} describes
the quark distribution functions in the pion reasonably well. Taking into
account cascade-like processes in a generalized jet-model approach, we then
show that the momentum and isospin sum rules can be satisfied naturally,
without the introduction of ad hoc parameters. We present results for the
Nambu--Jona-Lasinio (NJL) model in the invariant mass regularization scheme and
compare them with the empirical parametrizations. We argue that the NJL-jet
model, developed herein, provides a useful framework with which to calculate
the fragmentation functions in an effective chiral quark theory.Comment: 21 pages, 7 figure
ONLINE LEARNING CHALLENGES: NEED FOR EVOLVING MODELS
This paper proposes that online learning theory can be enhanced by looking at research outside of education.Models such as the Community of Inquiry and the Transactional Distance Theoretical Model provide a utility toward structuring, conceptualizing, understanding, and analyzing online education. The ongoing research based on these models continues to explore and recommend as practice that the instructor holds "the keys" as to how the online learning environment will be formulated, shaped, and conducted. The assertion from this perspective continues that instructors through proper or improper structuring, guidance, and/or facilitation and design of their online learning environments may or may not be successful in their teaching. Research outside of education explores implications for online education from a biological and human behavior perspective, which includes analysis of innate brain wiring and emergent research regarding student emotional responses. If we think in terms of the online learning context and the apparent innate desire by all while learning to "connect" to one another, mirroring neurons and the advancement of their understanding could and should be monitored closely as more information and evidence emerges that may have valuable revelations about improving learning and learning outcomes within asynchronous learning environments. "Setting up" the space for learning is not enough for an online educator to understand. Having insight into one's own and others' personal relational dynamics and group dynamics is critical in facilitating online learning environments. Understanding the psyche of individuals and having the ability to intuit human behavior is equally important
ONLINE LEARNING CHALLENGES: NEED FOR EVOLVING MODELS
This paper proposes that online learning theory can be enhanced by looking at research outside of education.Models such as the Community of Inquiry and the Transactional Distance Theoretical Model provide a utility toward structuring, conceptualizing, understanding, and analyzing online education. The ongoing research based on these models continues to explore and recommend as practice that the instructor holds "the keys" as to how the online learning environment will be formulated, shaped, and conducted. The assertion from this perspective continues that instructors through proper or improper structuring, guidance, and/or facilitation and design of their online learning environments may or may not be successful in their teaching. Research outside of education explores implications for online education from a biological and human behavior perspective, which includes analysis of innate brain wiring and emergent research regarding student emotional responses. If we think in terms of the online learning context and the apparent innate desire by all while learning to "connect" to one another, mirroring neurons and the advancement of their understanding could and should be monitored closely as more information and evidence emerges that may have valuable revelations about improving learning and learning outcomes within asynchronous learning environments. "Setting up" the space for learning is not enough for an online educator to understand. Having insight into one's own and others' personal relational dynamics and group dynamics is critical in facilitating online learning environments. Understanding the psyche of individuals and having the ability to intuit human behavior is equally important
The near-infrared radius-luminosity relationship for active galactic nuclei
Black hole masses for samples of active galactic nuclei (AGN) are currently
estimated from single-epoch optical spectra. In particular, the size of the
broad-line emitting region needed to compute the black hole mass is derived
from the optical or ultraviolet continuum luminosity. Here we consider the
relationship between the broad-line region size, R, and the near-infrared
(near-IR) AGN continuum luminosity, L, as the near-IR continuum suffers less
dust extinction than at shorter wavelengths and the prospects for separating
the AGN continuum from host-galaxy starlight are better in the near-IR than in
the optical. For a relationship of the form R propto L^alpha, we obtain for a
sample of 14 reverberation-mapped AGN a best-fit slope of alpha=0.5+/-0.1,
which is consistent with the slope of the relationship in the optical band and
with the value of 0.5 naively expected from photoionisation theory. Black hole
masses can then be estimated from the near-IR virial product, which is
calculated using the strong and unblended Paschen broad emission lines (Pa
alpha or Pa beta).Comment: 5 pages, 2 figures, accepted by MNRAS Letter
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