10,494 research outputs found
A Mid-Infrared Galaxy Atlas (MIGA)
A mid-infrared atlas of part of the Galactic plane () has been constructed using HIRES processed infrared
data to provide a mid-infrared data set for the Canadian Galactic Plane Survey
(CGPS). The addition of this data set to the CGPS will enable the study of the
emission from the smallest components of interstellar dust at an angular
resolution comparable to that of the radio, millimetre, and far-infrared data
in the CGPS. The Mid-Infrared Galaxy Atlas (MIGA) is a mid-infrared (12 m
and 25 m) counterpart to the far-infrared IRAS Galaxy Atlas (IGA), and
consists of resolution enhanced ( resolution) HIRES images along
with ancillary maps. This paper describes the processing and characteristics of
the atlas, the cross-beam simulation technique used to obtain high-resolution
ratio maps, and future plans to extend both the IGA and MIGA.Comment: 38 pages (including 15 tables), 13 figures (8 dithered GIF and 5
EPS). Submitted to Astrophysical Journal Supplement Series. A preprint with
higher resolution figures is available at
http://www.cita.utoronto.ca/~kerton/publications.htm
A methodology for long-range prediction of air transportation
A framework and methodology for long term projection of demand for aviation fuels is presented. The approach taken includes two basic components. The first was a new technique for establishing the socio-economic environment within which the future aviation industry is embedded. The concept utilized was a definition of an overall societal objective for the very long run future. Within a framework so defined, a set of scenarios by which the future will unfold are then written. These scenarios provide the determinants of the air transport industry operations and accordingly provide an assessment of future fuel requirements. The second part was the modeling of the industry in terms of an abstracted set of variables to represent the overall industry performance on a macro scale. The model was validated by testing the desired output variables from the model with historical data over the past decades
Building a Sustainable Agricultural Career Pipeline: Effective Recruitment and Retention Practices Used by Colleges of Agriculture in the United States
This national study examined effective student recruitment and retention practices used by colleges of agriculture in the United States among 1862 land-grant, 1890 land-grant, and non-land-grant institutions. Respondents reported that faculty at colleges of agriculture were primarily white. Through the analysis of sub-group percentages, the researchers found that the ethnic makeup of faculty was not reflective of the general population. The researchers found that administrators from 1862 land-grant institutions reported statistically significant differences (p \u3c .05) regarding the use of specific strategies to target underrepresented populations in student recruitment as compared to other institutional types. Further, 1862 land-grant institutions reported statistically significant differences in student retention strategies (p \u3c .05) as compared to other institutional types regarding the delivery of programs that aimed to retain first-year students. Based on key findings from this investigation, the authors developed the agricultural student retention model (ASRM) to help guide colleges of agriculture in improving their holistic retention program as they navigate inclusive and diverse institutional contexts. Additionally, key recruitment strategies were identified as well, that could facilitate holistic student recruitment efforts. Perhaps more significant progress can be made toward creating a sustainable agricultural workforce that is more reflective of U.S. population demographics using this model
Image-Processing Techniques for the Creation of Presentation-Quality Astronomical Images
The quality of modern astronomical data, the power of modern computers and
the agility of current image-processing software enable the creation of
high-quality images in a purely digital form. The combination of these
technological advancements has created a new ability to make color astronomical
images. And in many ways it has led to a new philosophy towards how to create
them. A practical guide is presented on how to generate astronomical images
from research data with powerful image-processing programs. These programs use
a layering metaphor that allows for an unlimited number of astronomical
datasets to be combined in any desired color scheme, creating an immense
parameter space to be explored using an iterative approach. Several examples of
image creation are presented.
A philosophy is also presented on how to use color and composition to create
images that simultaneously highlight scientific detail and are aesthetically
appealing. This philosophy is necessary because most datasets do not correspond
to the wavelength range of sensitivity of the human eye. The use of visual
grammar, defined as the elements which affect the interpretation of an image,
can maximize the richness and detail in an image while maintaining scientific
accuracy. By properly using visual grammar, one can imply qualities that a
two-dimensional image intrinsically cannot show, such as depth, motion and
energy. In addition, composition can be used to engage viewers and keep them
interested for a longer period of time. The use of these techniques can result
in a striking image that will effectively convey the science within the image,
to scientists and to the public.Comment: 104 pages, 38 figures, submitted to A
Numerical modelling of the lobes of radio galaxies in cluster environments -- IV. Remnant radio galaxies
© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.We examine the remnant phase of radio galaxies using three-dimensional hydrodynamical simulations of relativistic jets propagating through cluster environments. By switching the jets off once the lobes have reached a certain length we can study how the energy distribution between the lobes and shocked intra-cluster medium compares to that of an active source, as well as calculate synchrotron emission properties of the remnant sources. We see that as a result of disturbed cluster gas beginning to settle back into the initial cluster potential, streams of dense gas are pushed along the jet axis behind the remnant lobes, causing them to rise out of the cluster faster than they would due to buoyancy. This leads to increased adiabatic losses and a rapid dimming. The rapid decay of total flux density and surface brightness may explain the small number of remnant sources found in samples with a high flux density limit and may cause analytic models to overestimate the remnant fraction expected in sensitive surveys such as those now being carried out with LOFAR.Peer reviewedFinal Accepted Versio
A study of characteristics of intercity transportation systems. Phase 1: Definition of transportation comparison methodology
Decision making in early transportation planning must be responsive to complex value systems representing various policies and objectives. The assessment of alternative transportation concepts during the early initial phases of the system life cycle, when supportive research and technology development activities are defined, requires estimates of transportation, environmental, and socio-economic impacts throughout the system life cycle, which is a period of some 40 or 50 years. A unified methodological framework for comparing intercity passenger and freight transportation systems is described and is extended to include the comparison of long term transportation trends arising from implementation of the various R & D programs. The attributes of existing and future transportation systems are reviewed in order to establish measures for comparison, define value functions, and attribute weightings needed for comparing alternative policy actions for furthering transportation goals. Comparison criteria definitions and an illustrative example are included
Experimental Generation and Observation of Intrinsic Localized Spin Wave Modes in an Antiferromagnet
By driving with a microwave pulse the lowest frequency antiferromagnetic
resonance of the quasi 1-D biaxial antiferromagnet (C_2 H_5 NH_3)_2 CuCl_4 into
an unstable region intrinsic localized spin waves have been generated and
detected in the spin wave gap. These findings are consistent with the
prediction that nonlinearity plus lattice discreteness can lead to localized
excitations with dimensions comparable to the lattice constant.Comment: 10 pages, 4 figures, accepted for publication in Physical Review
Letter
THE DERIVED DEMAND FOR IRRIGATION SCHEDULING SERVICES
Scientific irrigation scheduling is a technique for systematically determining the proper date and quantity of each irrigation in individual fields. This technique is presently being used by government agencies and private companies in the Western United States to assist farmers in planning irrigations. This paper presents the results of a case study of the regional economic effects of scheduling the A & B District in Idaho. The analysis indicated that substantial reductions in total water use resulted from implementation of the service. However, the acreage of scheduled irrigation actively was found to be sensitive to the cost of the service and the cost of irrigation water.Farm Management,
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