8,968 research outputs found
Perspectives on subnational carbon and climate footprints: A case study of Southampton, UK
Sub-national governments are increasingly interested in local-level climate change management. Carbon- (CO2 and CH4) and climate-footprints—(Kyoto Basket GHGs) (effectively single impact category LCA metrics, for global warming potential) provide an opportunity to develop models to facilitate effective mitigation. Three approaches are available for the footprinting of sub-national communities. Territorial-based approaches, which focus on production emissions within the geo-political boundaries, are useful for highlighting local emission sources but do not reflect the transboundary nature of sub-national community infrastructures. Transboundary approaches, which extend territorial footprints through the inclusion of key cross boundary flows of materials and energy, are more representative of community structures and processes but there are concerns regarding comparability between studies. The third option, consumption-based, considers global GHG emissions that result from final consumption (households, governments, and investment). Using a case study of Southampton, UK, this chapter develops the data and methods required for a sub-national territorial, transboundary, and consumption-based carbon and climate footprints. The results and implication of each footprinting perspective are discussed in the context of emerging international standards. The study clearly shows that the carbon footprint (CO2 and CH4 only) offers a low-cost, low-data, universal metric of anthropogenic GHG emission and subsequent management
A VLA Survey For Faint Compact Radio Sources in the Orion Nebula Cluster
We present Karl G. Janksy Very Large Array (VLA) 1.3 cm, 3.6 cm, and 6 cm
continuum maps of compact radio sources in the Orion Nebular Cluster. We
mosaicked 34 square arcminutes at 1.3 cm, 70 square arcminutes at 3.6 cm and
109 square arcminutes at 6 cm, containing 778 near-infrared detected YSOs and
190 HST-identified proplyds (with significant overlap between those
characterizations). We detected radio emission from 175 compact radio sources
in the ONC, including 26 sources that were detected for the first time at these
wavelengths. For each detected source we fit a simple free-free and dust
emission model to characterize the radio emission. We extrapolate the free-free
emission spectrum model for each source to ALMA bands to illustrate how these
measurements could be used to correctly measure protoplanetary disk dust masses
from sub-millimeter flux measurements. Finally, we compare the fluxes measured
in this survey with previously measured fluxes for our targets, as well as four
separate epochs of 1.3 cm data, to search for and quantify variability of our
sources.Comment: 13 pages, 6 figures, 4 tables, ApJ, in pres
SDSS J142625.71+575218.3: A Prototype for A New Class of Variable White Dwarf
We present the results of a search for pulsations in six of the recently discovered carbon-atmosphere white dwarf ("hot DQ") stars. On the basis of our theoretical calculations, the star SDSS J142625.71 + 575218.3 is the only object expected to pulsate. We observe this star to be variable, with significant power at 417.7 s and 208.8 s ( first harmonic), making it a strong candidate as the first member of a new class of pulsating white dwarf stars, the DQVs. Its folded pulse shape, however, is quite different from that of other white dwarf variables and shows similarities with that of the cataclysmic variable AM CVn, raising the possibility that this star may be a carbon-transferring analog of AM CVn stars. In either case, these observations represent the discovery of a new and exciting class of object.NSF AST-0507639, AST-0602288, AST-0607480, AST-0307321Astronom
Landau-gauge condensates from the quark propagator on the lattice
We compute the dimension-2 condensate, , and the dimension-4 mixed
condensate, , from the recent quenched lattice results for the
quark propagator in the Landau gauge. We fit the lattice data to the Operator
Product Expansion in the "fiducial" region 1.2 GeV < Q < 3 GeV. Our result for
the dynamical gluon mass at the scale of 10 GeV^2 is m_A=600-650 MeV, in
agreement with independent determinations. For the mixed Landau gauge
condensate of dimension-4 we get alpha_s = (-0.11 +/- 0.03)
GeV^4. This value is an order of magnitude larger than the gluon
condensate.Comment: 4 pages, 3 figures, references adde
Pre-Service Educator Preparation to Teach Children with Disabilities Through Service-Learning
The purpose of the multi-year study discussed in this article was to investigate the impact of pre-service educator participation in a community-based service-learning program for children with disabilities. Pre-service educators who were enrolled in either an adapted physical education or introduction to special education course participated in the Children’s Adaptive Physical Education Society!, a skill-development program for 35 children (ages 5-12) with developmental disabilities. Two measures—a modified regular education initiative survey and a reflective blog assignment—were administered to the participants to identify changes in their beliefs and attitudes toward teaching and including children with disabilities in their future classrooms. The results revealed statistically significant gains in their understanding, confidence, willingness, skill set, and educational satisfaction. Responses in the reflective blogs further supported the statistical findings, suggesting that a community-based learning program provides pre-service educators with sufficient experiences to positively and effectively change their beliefs and attitudes toward teaching and including children with disabilities in their future classrooms
Role of center vortices in chiral symmetry breaking in SU(3) gauge theory
We study the behavior of the AsqTad quark propagator in Landau gauge on SU(3)
Yang-Mills gauge configurations under the removal of center vortices. In SU(2)
gauge theory, center vortices have been observed to generate chiral symmetry
breaking and dominate the infrared behavior of the quark propagator. In
contrast, we report a weak dependence on the vortex content of the gauge
configurations, including the survival of dynamical mass generation on
configurations with vanishing string tension.Comment: 8 pages, 9 figure
Flexible Execution of Plans with Choice
Dynamic plan execution strategies allow an autonomous
agent to respond to uncertainties while improving
robustness and reducing the need for an overly
conservative plan. Executives have improved this robustness
by expanding the types of choices made dynamically,
such as selecting alternate methods. However,
in methods to date, these additional choices introduce
substantial run-time latency. This paper presents a
novel system called Drake that makes steps towards executing
an expanded set of choices dynamically without
significant latency.
Drake frames a plan as a Disjunctive Temporal Problem
and executes it with a fast dynamic scheduling algorithm.
Prior work demonstrated an efficient technique
for dynamic execution of one special type of DTPs by
using an off-line compilation step to find the possible
consistent choices and compactly record the differences
between them. Drake extends this work to handle a
more general set of choices by recording the minimal
differences between the solutions which are required at
run-time. On randomly generated structured plans with
choice, we show a reduction in the size of the solution
set of over two orders of magnitude, compared to prior
art
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