3,928 research outputs found
Middle School Teachersâ Perceptions Of Homework Assignments Effective At Increasing Student Homework Completion
The purpose of this qualitative exploratory research study with a phenomenological research design was to gain an understanding of the phenomenon regarding which homework assignments, as perceived by middle school teachers, most effectively resulted in students submitting completed assignments. This study fills a gap and helps explain which homework assignments are more effective at increasing homework assignment completion for middle school students. The constructivist theory guided the conceptual framework. Data analysis was conducted on data collected though surveys, in-depth interviews with middle school teachers, and a review of archival homework samples. Through this phenomenological study four themes emerged regarding teacher perceptions of which homework assignments are more effective: routine homework, homework with clear expectations, homework that students see as achievable, and homework assignments that considered the executive functioning of students. It was found that middle school teachersâ perceptions about increasing student homework assignment completion reflect the value of structural supports, ongoing homework development, and the assignment of the homework itself. Persons in educational administrative leadership, middle school teachers, and teachers in general may find this study useful
Twisted algebra R-matrices and S-matrices for affine Toda solitons and their bound states
We construct new and invariant
-matrices and comment on the general construction of -matrices for
twisted algebras. We use the former to construct -matrices for
affine Toda solitons and their bound states, identifying the lowest breathers
with the particles.Comment: Latex, 24 pages. Various misprints corrected. New section added
clarifying relationship between R-matrices and S-matrice
On Estimating the High-Energy Cutoff in the X-ray Spectra of Black Holes via Reflection Spectroscopy
The fundamental parameters describing the coronal spectrum of an accreting
black hole are the slope of the power-law continuum and the energy
at which it rolls over. Remarkably, this parameter can be accurately
measured for values as high as 1 MeV by modeling the spectrum of X-rays
reflected from a black hole accretion disk at energies below 100 keV. This is
possible because the details in the reflection spectrum, rich in fluorescent
lines and other atomic features, are very sensitive to the spectral shape of
the hardest coronal radiation illuminating the disk. We show that fitting
simultaneous NuSTAR (3-79 keV) and low-energy (e.g., Suzaku) data with the most
recent version of our reflection model RELXILL, one can obtain reasonable
constraints on at energies from tens of keV up to 1 MeV, for a source
as faint as 1 mCrab in a 100 ks observation.Comment: Accepted for publication in ApJL, 6 pages, 5 figure
When do followers perceive their leaders as ethical? A relational models perspective of normatively appropriate conduct
In the aftermath of various corporate scandals, management research and practice have taken great interest in ethical leadership. Ethical leadership is referred to as ânormatively appropriate conductâ (Brown et al. in Organ Behav Hum Decis Process 97(2):117â134, 2005), but the prescriptive norms that actually underlie this understanding constitute an open question. We address this research gap by turning to relational models theory (Fiske in Structures of social life: the four elementary forms of human relations, Free Press, New York, 1991), which contextualizes four distinct moralities in four distinct interactional norms (i.e., the relational models). We expect that the norms inherent in each model dictate the type of leader relationship that followers deem ethical. Specifically, we hypothesize that, for each norm, followers will perceive leaders as less ethical the more discrepant, i.e., the more incongruent, followersâ ideal relational norm is with the perceived norm that they attribute to their actual leaderâfollower interaction. We tested the respective incongruence hypothesis in a cross-sectional survey of 101 Dutch employees. Polynomial regression and surface response analyses provide support for the hypothesized incongruence effects in each of the four relational models, suggesting that normatively appropriate conduct should not be limited to caring (i.e., community-oriented) behaviors. Indeed, all four relational models can predict ethical leadership perceptions. We discuss the implications in the context of ethical leadership research and managerial practice
The Transition State in a Noisy Environment
Transition State Theory overestimates reaction rates in solution because
conventional dividing surfaces between reagents and products are crossed many
times by the same reactive trajectory. We describe a recipe for constructing a
time-dependent dividing surface free of such recrossings in the presence of
noise. The no-recrossing limit of Transition State Theory thus becomes
generally available for the description of reactions in a fluctuating
environment
Stochastic Transition States: Reaction Geometry amidst Noise
Classical transition state theory (TST) is the cornerstone of reaction rate
theory. It postulates a partition of phase space into reactant and product
regions, which are separated by a dividing surface that reactive trajectories
must cross. In order not to overestimate the reaction rate, the dynamics must
be free of recrossings of the dividing surface. This no-recrossing rule is
difficult (and sometimes impossible) to enforce, however, when a chemical
reaction takes place in a fluctuating environment such as a liquid.
High-accuracy approximations to the rate are well known when the solvent forces
are treated using stochastic representations, though again, exact no-recrossing
surfaces have not been available. To generalize the exact limit of TST to
reactive systems driven by noise, we introduce a time-dependent dividing
surface that is stochastically moving in phase space such that it is crossed
once and only once by each transition path
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