8,730 research outputs found
Constant Scalar Curvature Metrics on Boundary Complexes of Cyclic Polytopes
In [7], a notion of constant scalar curvature metrics on piecewise flat
manifolds is defined. Such metrics are candidates for canonical metrics on
discrete manifolds. In this paper, we define a class of vertex transitive
metrics on certain triangulations of ; namely, the boundary
complexes of cyclic polytopes. We use combinatorial properties of cyclic
polytopes to show that, for any number of vertices, these metrics have constant
scalar curvature.Comment: 15 pages, 4 figure
Jewish Community Study of New York: 2011 Special Report on Poverty
The sheer scale of needs associated with being poor or near poor dwarfs the resources of even the largest Jewish community in the United States. One is tempted to believe that the scale of need is so vast that the Jewish community should abandon this field to others.Yet since the earliest days of Jewish communal life in New York, the organized Jewish community has accepted its responsibilities to care for those in need. Even since the New Deal, when the federal government took on the primary role of providing a societal safety net, the Jewish community has been active in providing philanthropic support and services for poor and near-poor Jews.The numbers of poor and near-poor Jewish households, the enormous increase in the number of these households over the past 20 years, and the diverse groups affected by poverty create an imperative for an extraordinary response -- from government, the voluntary sector, the philanthropic sector, and all segments of society. These findings suggest that the organized Jewish community needs to take a hard look at current planning, advocacy, service delivery, and resource investment
Economic Contribution of Agriculture and Food to Arkansas\u27 Gross Domestic Product 1997-2011
Agricultural production, processing, and retail industries are major contributors to the Arkansas economy in terms of GDP. Agriculture contributes to the economy through direct agricultural production, value-added processing, and agricultural retail activities, and it also plays an important role through its interactions with other sectors. The use of non-agricultural goods and services as inputs into the agricultural sector promotes diversified growth in Arkansas’ economy; thus agriculture remains a vital part of Arkansas’ economy. Part 1 of the report compares the relative size of the Agriculture and Food Sector in Arkansas with those of neighboring states, the Southeastern region of the United States, and the nation; provides an overview of Arkansas’ economy and discusses Arkansas’ agricultural sector in relation to the state economy; and examines components of agricultural production and processing, including a review of historical sales trends for raw and processed agricultural output
Redesigning Airport Diagrams with Principles of Cognitive Psychology
The aviation community strives for air travel to be the safest form of transportation. The National Transportation Safety Board published a “Most Wanted” list to acknowledge the most threatening safety issues, and runway safety and runway incursions were at the top of their list. Furthermore, runway incursion statistics by the Federal Aviation Administration show that pilot deviations were the most common cause for runways incursions. Misunderstandings of airport diagrams may be one reason for pilot deviations. While navigating through airport taxiways, pilots refer to their airport diagrams as a map of the airport. Unfortunately, airport diagrams are not designed with the pilot in mind. This study attempted to redesign airport diagrams to incorporate principles of cognitive psychology. The redesigned airport diagrams included decreasing extra information, increasing overall size, and adding color. The study measured the participant’s situational awareness and deviations throughout six simulated taxiing tasks. The results were not statistically significant. The results showed evidence of a ceiling effect which may indicate that the taxiing tasks were too easy to show performance differences. This research issues should not be abandoned. However, future studies should include increased workload within the experimental tasks to create a more realistic cockpit environment
An analysis of the preferences, morphometrics, and survey efficacy of the freshwater mussel community in the Greenup pool, Ohio River
The Greenup Pool is one of the most unique pools of the Ohio River in terms of habitat richness and anthropogenic impact both historical and current. The Greenup Pool spans 61.8 miles reaching from Greenup Dam in Greenup, KY to Robert C. Byrd Dam in Apple Grove, WV. We surveyed 17 sites to assess mussel communities within the Greenup Pool using the 2017 West Virginia Mussel Survey Protocol. At these sites, six 100-meter transects were surveyed for surface and subsurface mussels. Each transect was divided into 10-meter intervals. These surveys resulted in 4,041 live individuals from 21 species, including eight federally endangered Plethobasus cyphyus. This effort furthers our understanding of the Greenup Pool mussel community and identifies the outside bends and straightaways of the upper Greenup Pool as their preferred habitat. Habitat selection may be a result of lower historic impact in the Upper Pool and appears to be influenced by the coverage of fine sediment. Additionally, morphometric data indicates a severe lack of recent reproduction in the Greenup Pool, suggesting many species are only present as large, old individuals. The mussel community identified in this effort was compared to a prior Greenup Pool survey effort in 2017 using a similar site selection process and survey protocol. The analysis of the two efforts concluded the initial 2017 survey captured the mussel community based on the results of this effort. The combined data from both efforts is potentially the largest and most up to date mussel community resource for an individual navigational pool in the Ohio River
Behavior and measurement of distributed sources in a shielding matrix using gamma spectroscopy
As part of its mission, the Department of Energy generates transuranic waste materials. Some of these wastes are present in large waste containers. The accurate assay of these waste materials in large containers poses unique challenges. These wastes have radioactive sources that are spread throughout the container with a variety of waste matrices that provide shielding. Although multiple well established and validated methods that use active and/or passive neutron detection in conjunction with gamma spectroscopy exist to assay these waste materials, these methods are expensive and not readily available at any given facility. As a result, less expensive alternatives, such as gamma spectroscopy alone, are often used. This paper researches the impact of a distributed shielding medium on a distributed transuranic source and the physical limitations of using gamma spectroscopy alone, without the benefit of either active or passive neutron counting. This included comparing the assay results from a gamma spectroscopy based system to one that uses passive neutron counting in addition to gamma spectroscopy. The differences between these systems were noted, and then evaluated through modeling using MCNPX to determine the cause of the observed discrepancies
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