636 research outputs found
Effective matter dispersion relation in quantum covariant Horava-Lifshitz gravity
We study how quantum fluctuations of the metric in covariant Horava-Lifshitz
gravity influence the propagation of classical fields (complex scalar and
photon). The effective Lorentz-symmetry violation induced by the breaking of
4-dimensional diffeomorphism is then evaluated, by comparing the dressed
dispersion relations for both external fields. The constraint of vanishing
3-dimensional Ricci scalar is imposed in the path integral, which therefore
explicitly depends on two propagating gravitational degrees of freedom only.
Because the matter fields are classical, the present model contains only
logarithmic divergences. Furthermore, it imposes the characteristic
Horava-Lifshitz scale to be smaller than GeV, if one wishes not to
violate the current bounds on Lorentz symmetry violation.Comment: 11 pages, comments adde
On higher-order corrections in a four-fermion Lifshitz model
We study a flavour-violating four-fermion interaction in the Lifshitz
context, in 3+1 dimensions and with a critical exponent z=3. This model is
renormalizable, and features dynamical mass generation, as well as asymptotic
freedom. At one-loop, it is only logarithmically divergent, but the superficial
degree of divergence of the two-point functions is 3. We calculate the two-loop
corrections to the propagators, and show that, at this order, the
Lorentz-violating corrections to the IR dispersion relation are quadratic in
the cut off. Furthermore, these corrections are too important to represent a
physical effect. As a consequence, the predictive power of the model in terms
of Lorentz-violating effects in the propagation of particles is limited.Comment: 20 pages, 3 figures, comments adde
Presettlement Forest Composition in the Connecticut Tract of Western New York
This study of the vegetation of the 100,000-acre Connecticut Tract in western New York examines the presettlement characteristics of the forest, including the tree species composition, tree density, and wetland extent. Presettlement vegetation studies add to what is known about the forests of this region before European settlement in the early 1800s brought widespread changes to these forests. The ecological data in original private land surveys from 1811 were transcribed and then analyzed using ArcGIS and IDRISI GIS software. The surveys contained both witness tree data and line descriptions, which were analyzed for species composition and community type and were compared with Forest Inventory and Analysis (FIA) data about the contemporary forest in the study area. The community type results together with surveyor notes were used to extrapolate wetland coverage, which was compared with the 2006 National Wetlands Inventory Database.
This study fills in missing historical data between the two largest land purchases in western New York and examines forest composition at a finer-grained scale than surveys of those land purchases. Comparing past and present vegetation clarifies past causes of temporal and spatial variability and provides a reference point for land managers who need to understand the effects of land-use history for ongoing restoration efforts
The songs of Madeleine Dring: Organizing a posthumous legacy
This document is dedicated to the published songs of British composer Madeleine Dring (1923--1977). A look at Dring\u27s musical background, upbringing, training, and career is followed by a close examination of her art songs for solo voice. A breakdown of her vocal works includes many musical examples. Dring, composer of works for solo piano, pieces for small ensemble, and for voice and piano, was quite active as a composer in the 1940s through her premature death in 1977. Few of her pieces for voice and piano were published at the time of her death. This study relates the journey of her widower, Roger Lord, in having Dring\u27s pieces made accessible and recorded in hopes of their acceptance into the standard vocal repertoire; Assessment of each of the thirty-eight published and readily available art songs examines the texts, their specific musical challenges, and compositional devices. Mention of the other songs is included; This paper quotes and annotates many excerpts from Dring\u27s letters, diaries and speeches. Ten photographs documenting her life are included. Also cited are excerpts from nearly four years of correspondence with Roger Lord; Appendices include lists of seventy-six musical examples, correspondence from Roger Lord to the author, a ten-year chronology of Dring\u27s correspondence with Eugene Hemmer, a directory of the songs by title, and a list of photographs; Representing a direct link to the composer, this document is on a topic that has gone largely unnoticed in the United States
Western Organization of Resource Councils v. Zinke
Due to advances in climate science and an increased understanding of coal’s role as a greenhouse gas, Appellant conservation organizations sued the Secretary of Interior for failing to supplement the 1979 Programmatic EIS for the Federal Coal Management Program. The D.C. Circuit Court held neither NEPA nor the APA required a supplemental EIS and that the court lacked jurisdiction to compel the Secretary to prepare one. Expressing sympathy for the Appellants’ position, the D.C. Circuit took the unusual step of offering advice to future plaintiffs on how they might succeed on similar claims
Participation in Open Up Resources by Gender and Family Income Level on Mathematics Achievement of Grades 7 and 8 Students
The purpose of this dissertation was to determine the effects by gender and by family-income level between students using Open Up Resources (OUR) curriculum (a Problem-Based Learning [PBL] curriculum) versus traditional curriculum on mathematics achievement of Grades 7 and 8 students. A stratified random sample of 320 students from four Central and Southeast Arkansas schools (n = 160 for Grades 7 and 8, respectively) was drawn for this study. Data analysis involved the use of 2 x 2 factorial ANOVAs. The key findings of the study were that the mathematics achievement of Grade 8 students using OUR was significantly higher than the scores of those using traditional mathematics curricula. The scores of Grade 7 students using both curriculum types were similar. Seventh-grade females had higher mathematics achievement than males. Students from low family-income levels had lower mathematics achievement in both grades than those from higher family-income levels. Based on these findings, PBL curricula such as OUR are recommended as a strategy for closing gaps in mathematics achievement
Massachusetts Lobstermen’s Association v. Ross
President Obama established the first––and only––national monument in the Atlantic Ocean on September 15, 2016. Located 130 miles southeast of Cape Cod, Massachusetts, and comprised of 4,913 square miles of marine ecosystems rich in biodiversity, the protected area includes four underwater mountains and three submarine canyons. Plaintiff commercial lobster and fishing associations, seeking to overturn the designation, asserted that the Antiquities Act does not permit a president to establish marine national monuments. The U.S. District Court for the District of Columbia disagreed, upholding a president’s authority to protect offshore areas and vast ecosystems as objects of scientific interest, and dismissing the Lobstermen’s case in a memorandum opinion splashed with maritime references
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