Physical Sciences and Mathematics Commons^™

Non-Gaussianity From Self-Ordering Scalar Fields, Daniel G. Figueroa, Robert R. Caldwell, Marc Kamionkowski

Dartmouth Scholarship

The Universe may harbor relics of the post-inflationary epoch in the form of a network of self-ordered scalar fields. Such fossils, while consistent with current cosmological data at trace levels, may leave too weak an imprint on the cosmic microwave background and the large-scale distribution of matter to allow for direct detection. The non-Gaussian statistics of the density perturbations induced by these fields, however, permit a direct means to probe for these relics. Here we calculate the bispectrum that arises in models of self-ordered scalar fields. We find a compact analytic expression for the bispectrum, evaluate it numerically, and provide …

A Comparison Of Copepoda (Order: Calanoida, Cyclopoida, Poecilostomatoida) Density In The Florida Current Off Fort Lauderdale, Florida, Jessica L. Bostock

HCNSO Student Theses and Dissertations

Copepods, minute crustaceans, are vital constituents of marine food web dynamics in tropical ecosystems. Ecologically, copepods provide the link between primary production and tertiary consumers. Changes in population structure and densities may impact ecosystem stability and production on small to large spatial scales. The present study examined the influence of the Florida Current on copepod population densities off the coast of Fort Lauderdale, Florida due to limited data in the area. Samples were collected during February and July 2007 at two locations, Stations A and B. Station A, dependent on current dynamics, fluctuated between the most western boundary and the …

Estimates Of Toad Headed Agama Density In Three Steppe Habitats Of Mongolia, James Murdoch, Buyandelger Suuri, Richard P. Reading

Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298

The toad headed agama (Phrynocephalus versicolor) ranges across the arid steppe regions of southern and western Mongolia and represents one of the most common reptiles in the country. However, few details of the species’ population characteristics exist, which may be important for evaluating population trends and assessing its conservation status. We estimated toad headed agama density in Ikh Nart Nature Reserve, Mongolia based on surveys conducted in the summers (June-September) of 2005, 2006, 2008, and 2009. We conducted surveys in three steppe habitats including tall grassland (n = 7), shrub-steppe (n = 7), and semi-shrub steppe …

Evolving Models: A Density-Based Approach To Modeling Sexual Dimorphism And Adaptive Speciation, Audrey Smith

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

In this paper, we begin by extending existing deterministic and individual-based ecological models for sexual dimorphism and adaptive speciation into density-based mathematical models describing the density or number of individuals with various trait values, or phenotypes. These density-based models describe the dynamics of a population of males and females using both clonal and sexual reproduction. Each generation, the populations are subject to mating, mutation, and ecological dynamics including infraspecific competition and carrying capacity of the environment. By avoiding individual-based models, we are able to avoid simulations and instead achieve repeatable results.

Implementing these models numerically, we are able to show …