703 research outputs found
Teacher Burnout: Locus of Control and its Correlation to Teacher Burnout and Job Satisfaction
Teacher burnout is a significant problem in education today. While studies have researched the possible reasons behind it and the effect it has on students and teachers, this study proposed to investigate the correlation between teacher burnout, locus of control and job satisfaction. Surveys were sent to 102 teachers who taught kindergarten through 12th grade in two school districts in Southeastern Ohio. Of the 53 surveys that were returned, 28% of the teachers demonstrated burn out, 40% were dissatisfied with their jobs, and 20% had an external locus of control. There was a moderate correlation between the Rotter IE Scale, which measures locus of control, and the Teacher Burnout Scale. There was no significant relationship between the Rotter IE Scale and the Teacher Job Satisfaction Questionnaire
Cosmic string Y-junctions: a comparison between field theoretic and Nambu-Goto dynamics
We explore the formation of cosmic string Y-junctions when strings of two
different types collide, which has recently become important since string
theory can yield cosmic strings of distinct types. Using a model containing two
types of local U(1) string and stable composites, we simulate the collision of
two straight strings and investigate whether the dynamics matches that
previously obtained using the Nambu-Goto action, which is not strictly valid
close to the junction. We find that the Nambu-Goto action performs only
moderately well at predicting when the collision results in the formation of a
pair of Y-junctions (with a composite string connecting them). However, we find
that when they do form, the late time dynamics matches those of the Nambu-Goto
approximation very closely. We also see little radiative emission from the
Y-junction system, which suggests that radiative decay due to bridge formation
does not appear to be a means via which a cosmological network of such string
would rapidly lose energy.Comment: 17 pages, 17 figures; typo correctio
CMB power spectra from cosmic strings: predictions for the Planck satellite and beyond
We present a significant improvement over our previous calculations of the
cosmic string contribution to cosmic microwave background (CMB) power spectra,
with particular focus on sub-WMAP angular scales. These smaller scales are
relevant for the now-operational Planck satellite and additional sub-orbital
CMB projects that have even finer resolutions. We employ larger Abelian Higgs
string simulations than before and we additionally model and extrapolate the
statistical measures from our simulations to smaller length scales. We then use
an efficient means of including the extrapolations into our Einstein-Boltzmann
calculations in order to yield accurate results over the multipole range 2 < l
3000 in
the case of the temperature power spectrum, which then allows cautious
extrapolation to even smaller scales. We find that a string contribution to the
temperature power spectrum making up 10% of power at l=10 would be larger than
the Silk-damped primary adiabatic contribution for l > 3500. Astrophysical
contributions such as the Sunyaev-Zeldovich effect also become important at
these scales and will reduce the sensitivity to strings, but these are
potentially distinguishable by their frequency-dependence.Comment: 18 pages, 16 figure
Abelian Higgs Cosmic Strings: Small Scale Structure and Loops
Classical lattice simulations of the Abelian Higgs model are used to
investigate small scale structure and loop distributions in cosmic string
networks. Use of the field theory ensures that the small-scale physics is
captured correctly. The results confirm analytic predictions of Polchinski &
Rocha [1] for the two-point correlation function of the string tangent vector,
with a power law from length scales of order the string core width up to
horizon scale with evidence to suggest that the small scale structure builds up
from small scales. An analysis of the size distribution of string loops gives a
very low number density, of order 1 per horizon volume, in contrast with
Nambu-Goto simulations. Further, our loop distribution function does not
support the detailed analytic predictions for loop production derived by Dubath
et al. [2]. Better agreement to our data is found with a model based on loop
fragmentation [3], coupled with a constant rate of energy loss into massive
radiation. Our results show a strong energy loss mechanism which allows the
string network to scale without gravitational radiation, but which is not due
to the production of string width loops. From evidence of small scale structure
we argue a partial explanation for the scale separation problem of how energy
in the very low frequency modes of the string network is transformed into the
very high frequency modes of gauge and Higgs radiation. We propose a picture of
string network evolution which reconciles the apparent differences between
Nambu-Goto and field theory simulations.Comment: 16 pages, 17 figure
Geodesic motion in the space-time of cosmic strings interacting via magnetic fields
We study the geodesic motion of test particles in the space-time of two
Abelian-Higgs strings interacting via their magnetic fields. These bound states
of cosmic strings constitute a field theoretical realization of p-q-strings
which are predicted by inflationary models rooted in String Theory, e.g. brane
inflation. In contrast to previously studied models describing p-q-strings our
model possesses a Bogomolnyi-Prasad-Sommerfield (BPS) limit. If cosmic strings
exist it would be exciting to detect them by direct observation. We propose
that this can be done by the observation of test particle motion in the
space-time of these objects. In order to be able to make predictions we have to
solve the field equations describing the configuration as well as the geodesic
equation numerically. The geodesics can then be classified according to the
test particle's energy, angular momentum and momentum along the string axis. We
find that the interaction of two Abelian-Higgs strings can lead to the
existence of bound orbits that would be absent without the interaction. We also
discuss the minimal and maximal radius of orbits and comment on possible
applications in the context of gravitational wave emission.Comment: v1: 22 pages including 17 figures; v2: new figure added, section on
observables added; acccepted for publication in Phys. Rev.
CMB power spectrum contribution from cosmic strings using field-evolution simulations of the Abelian Higgs model
We present the first field-theoretic calculations of the contribution made by
cosmic strings to the temperature power spectrum of the cosmic microwave
background (CMB). Unlike previous work, in which strings were modeled as
idealized one-dimensional objects, we evolve the simplest example of an
underlying field theory containing local U(1) strings, the Abelian Higgs model.
Limitations imposed by finite computational volumes are overcome using the
scaling property of string networks and a further extrapolation related to the
lessening of the string width in comoving coordinates. The strings and their
decay products, which are automatically included in the field theory approach,
source metric perturbations via their energy-momentum tensor, the unequal-time
correlation functions of which are used as input into the CMB calculation
phase. These calculations involve the use of a modified version of CMBEASY,
with results provided over the full range of relevant scales. We find that the
string tension required to normalize to the WMAP 3-year data at multipole
is , where we have quoted statistical and systematic errors
separately, and is Newton's constant. This is a factor 2-3 higher than
values in current circulation.Comment: 23 pages, 14 figures; further optimized figures for 1Mb size limit,
appendix added before submission to journal, matches accepted versio
Interactions of Cosmic Superstrings
We develop methods by which cosmic superstring interactions can be studied in
detail. These include the reconnection probability and emission of radiation
such as gravitons or small string loops. Loop corrections to these are
discussed, as well as relationships to -strings. These tools should
allow a phenomenological study of string models in anticipation of upcoming
experiments sensitive to cosmic string radiation.Comment: 22 pages, 6 figures; v2: updated reference
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