14,200 research outputs found
Defining the gap between research and practice in public relations programme evaluation - towards a new research agenda
The current situation in public relations programme evaluation is neatly summarized by McCoy who commented that 'probably the most common buzzwords in public relations in the last ten years have been evaluation and accountability' (McCoy 2005, 3). This paper examines the academic and practitioner-based literature and research on programme evaluation and it detects different priorities and approaches that may partly explain why the debate on acceptable and agreed evaluation methods continues. It analyses those differences and proposes a research agenda to bridge the gap and move the debate forward
Bacterial Source Tracking to Support the Development and Implementation of Watershed Protection Plans for the Lampasas and Leon Rivers: Lampasas River Watershed Final Report
The Bacterial Source Tracking to Support the Development and Implementation of Watershed Protection Plans for the Lampasas and Leon Rivers project was developed to provide supplemental information to stakeholders engaged in the development and implementation of watershed protection plans for each watershed. The Leon River is listed as an impaired water body for elevated levels of E. coli and does not support its designated contact recreation use. The Lampasas River was also considered impaired for elevated E. coli levels until 2010 when it was determined that the data listing the segment no longer met the state’s criteria for assessment. Through the watershed protection planning process, stakeholders in each watershed will use adaptive management to refine management strategies that will mitigate bacteria loading from potential sources of pollution within the watershed
Student understanding of rotational and rolling motion concepts
We investigated the common difficulties that students have with concepts
related to rotational and rolling motion covered in the introductory physics
courses. We compared the performance of calculus- and algebra-based
introductory physics students with physics juniors who had learned rotational
and rolling motion concepts in an intermediate level mechanics course.
Interviews were conducted with six physics juniors and ten introductory
students using demonstration-based tasks. We also administered free-response
and multiple-choice questions to a large number of students enrolled in
introductory physics courses, and interviewed six additional introductory
students on the test questions (during the test design phase). All students
showed similar difficulties regardless of their background, and higher
mathematical sophistication did not seem to help acquire a deeper
understanding. We found that some difficulties were due to related difficulties
with linear motion, while others were tied specifically to the more intricate
nature of rotational and rolling motion.Comment: 23 pages, 3 figures, 2 tables; it includes a multiple-choice test (in
Appendix B
The Phase Diagram of High Temperature QCD with Three Flavors of Improved Staggered Quarks
We report on progress in our study of high temperature QCD with three flavors
of improved staggered quarks. Simulations are being carried out with three
degenerate quarks with masses less than or equal to the strange quark mass,
, and with degenerate up and down quarks with masses in the range , and the strange quark mass fixed near its physical
value. For the quark masses studied to date we find rapid crossovers, which
sharpen as the quark mass is reduced, rather than bona fide phase transitions.Comment: Lattice 2003 (Nonzero temperature and density
VLBA Continuum and H I Absorption Observations of the Ultra-Luminous Infrared Galaxy IRAS 17208-0014
We present phase-referenced VLBI observations of the radio continuum emission
from, and the neutral hydrogen 21 cm absorption toward, the Ultra-Luminous
Infrared Galaxy IRAS 17208-0014. The observations were carried out at 1362 MHz
using the Very Long Baseline Array, including the phased Very Large Array as an
element. The high-resolution radio continuum images reveal a nuclear starburst
region in this galaxy, which is composed of diffuse emission approximately 670
x 340 pc on the plane of the sky, and a number of compact sources. These
sources are most likely to be clustered supernova remnants and/or luminous
radio supernovae. Their brightness temperatures range over (2.2-6.6) x 10^{5}
K, with radio spectral luminosities between (1-10) x 10^{21} W Hz^{-1}. The
total VLBI flux density of the starburst region is ~52 mJy, which is about 50%
of the total flux density detected with the VLA at arcsecond resolution. For
this galaxy, we derive a massive star formation rate of ~84pm13 M{_\odot}
yr^{-1}, and a supernova rate of ~4pm1 yr^{-1}. H I absorption is detected in
multiple components with optical depths ranging between 0.3 and 2.5, and
velocity widths between 58 and 232 km s^{-1}. The derived column densities,
assuming T_{s}=100 K, range over (10-26) x 10^{21} cm^{-2}. The H I absorption
shows a strong velocity gradient of 453 km s^{-1} across 0.36 arcsec (274 pc).
Assuming Keplerian motion, the enclosed dynamical mass is about 2.3 x 10^9
sin^{-2}i M{_\odot}, comparable to the enclosed dynamical mass estimated from
CO observations.Comment: 26 pages total, 6 figures. ApJ accepted. To appear in the April 1,
2003 issue of ApJ. For a version with better images, see
http://www.aoc.nrao.edu/~emomjian/IRAS.p
Surprising Connections Between General Relativity and Condensed Matter
This brief review is intended to introduce gravitational physicists to recent
developments in which general relativity is being used to describe certain
aspects of condensed matter systems, e.g., superconductivity.Comment: 14 pages; based on talk given at GR1
Inflating magnetically charged braneworlds
Numerical solutions of Einstein, scalar, and gauge field equations are found
for static and inflating defects in a higher-dimensional spacetime. The defects
have -dimensional core and magnetic monopole configuration in
extra dimensions. For symmetry-breaking scale below the critical value
, the defects are characterized by a flat worldsheet geometry and
asymptotically flat extra dimensions. The critical scale is comparable
to the higher-dimensional Planck scale and has some dependence on the gauge and
scalar couplings. For , the extra dimensions degenerate into a
`cigar', and for all static solutions are singular. The
singularity can be removed if the requirement of staticity is relaxed and
defect cores are allowed to inflate. The inflating solutions have de Sitter
worldsheets and cigar geometry in the extra dimensions. Exact analytic
solutions describing the asymptotic behavior of these inflating monopoles are
found and the parameter space of these solutions is analyzed.Comment: 35 pages, revtex, 18 eps figure
Recommended from our members
Influence of biomass combustion emissions on the distribution of acidic trace gases over the southern Pacific basin during austral springtime
This paper describes the large-scale distributions of HNO3, HCOOH, and CH3COOH over the central and South Pacific basins during the Pacific Exploratory Mission-Tropics (PEM-Tropics) in austral springtime. Because of the remoteness of this region from continental areas, low part per trillion by volume (pptv) mixing ratios of acidic gases were anticipated to be pervasive over the South Pacific basin. However, at altitudes of 2–12 km over the South Pacific, air parcels were encountered frequently with significantly enhanced mixing ratios (up to 1200 pptv) of acidic gases. Most of these air parcels were centered in the 3–7 km altitude range and occurred within the 15°−65°S latitudinal band. The acidic gases exhibited an overall general correlation with CH3Cl, PAN, and O3, suggestive of photochemical and biomass burning sources. There was no correlation or trend of acidic gases with common industrial tracer compounds (e.g., C2Cl4 or CH3CCl3). The combustion emissions sampled over the South Pacific basin were relatively aged exhibiting C2H2/CO ratios in the range of 0.2–2.2 pptv/ppbv. The relationships between acidic gases and this ratio were similar to what was observed in aged air parcels (i.e., \u3e3–5 days since they were over a continental area) over the western North Pacific during the Pacific Exploratory Mission-West Phases A and B (PEM-West A and B). In the South Pacific marine boundary layer a median C2H2/CO ratio of 0.6 suggested that this region was generally not influenced by direct inputs of biomass combustion emissions. Here we observed the lowest mixing ratios of acidic gases, with median values of 14 pptv for HNO3, 19 pptv for HCOOH, and 18 pptv for CH3COOH. These values were coincident with low mixing ratios of NOx(\u3c10 pptv), CO (≈50 parts per billion by volume (ppbv)), O3 (\u3c 20 ppbv), and long-lived hydrocarbons (e.g., C2H6 \u3c300 pptv). Overall, the PEM-Tropics data suggest an important influence of aged biomass combustion emissions on the distributions of acidic gases over the South Pacific basin in austral springtime
Towards the Final Fate of an Unstable Black String
Black strings, one class of higher dimensional analogues of black holes, were
shown to be unstable to long wavelength perturbations by Gregory and Laflamme
in 1992, via a linear analysis. We revisit the problem through numerical
solution of the full equations of motion, and focus on trying to determine the
end-state of a perturbed, unstable black string. Our preliminary results show
that such a spacetime tends towards a solution resembling a sequence of
spherical black holes connected by thin black strings, at least at intermediate
times. However, our code fails then, primarily due to large gradients that
develop in metric functions, as the coordinate system we use is not well
adapted to the nature of the unfolding solution. We are thus unable to
determine how close the solution we see is to the final end-state, though we do
observe rich dynamical behavior of the system in the intermediate stages.Comment: 17 pages, 7 figure
Monte Carlo study of the Widom-Rowlinson fluid using cluster methods
The Widom-Rowlinson model of a fluid mixture is studied using a new cluster
algorithm that is a generalization of the invaded cluster algorithm previously
applied to Potts models. Our estimate of the critical exponents for the
two-component fluid are consistent with the Ising universality class in two and
three dimensions. We also present results for the three-component fluid.Comment: 13 pages RevTex and 2 Postscript figure
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