The Effect of Different Monetary Regimes on Cointegration of the Term Structure: Evidence for Germany, the Netherlands, Switzerland, and the United Kingdom

This thesis examines monthly eurodeposit rates for the short-end of term structure as a cointegrated system of the term structure of interest rates, for Germany, the Netherlands, Switzerland, and the United Kindom during the period 1975-1990. The countries monetary regimes are examined in order to find sample periods that reflect changes in policies, in order to determine if the policies affect the cointegration results. The cointegration testing procedure of Johansen and Juselius is employed. The results found support for the expectation theory of the term structure when the countries focus on exchange rate or interest rates, and rejects the expectation theory when the focus is placed upon targeting a monetary aggregate

Rates of climatic niche evolution are correlated with species richness in a large and ecologically diverse radiation of songbirds

By employing a recently inferred phylogeny and museum occurrence records, we examine the relationship of ecological niche evolution to diversification in the largest family of songbirds, the tanagers (Thraupidae). We test whether differences in species numbers in the major clades of tanagers can be explained by differences in rate of climatic niche evolution. We develop a methodological pipeline to process and filter occurrence records. We find that, of the ecological variables examined, clade richness is higher in clades with higher climatic niche rate, and that this rate is also greater for clades that occupy a greater extent of climatic space. Additionally, we find that more speciose clades contain species with narrower niche breadths, suggesting that clades in which species are more successful at diversifying across climatic gradients have greater potential for speciation or are more buffered from the risk of extinction.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111277/1/ele12422.pd

The effect of habitat and body size on the evolution of vocal displays in Thraupidae (tanagers), the largest family of songbirds

© 2015 The Linnean Society of London. Animals rely on auditory cues to relay important information between individuals regarding territoriality, mating status, and individual condition. The efficacy of acoustic signals can depend on many factors, including the transmitter, the receiver, and the signalling environment. In the present study, we evaluate the effect of body size and habitat on the evolution of learned vocal displays across the tanagers (Aves: Thraupidae), a group that comprises nearly 10% of all songbird species. We find that body size affects tanager vocalizations, such that nine out of ten song characters and scores from two principal component axes were correlated with mass. More specifically, larger tanagers tended to produce slower-paced, lower-pitched vocal displays within narrower bandwidths. In contrast, habitat was correlated with only three out of ten song characters, and only one of these characters corroborated the directional predictions of the acoustic adaptation hypothesis. Thus, morphological characters, such as body mass, may play a more important role than variation among signalling environments in the evolution of avian vocal displays

Elaborate visual and acoustic signals evolve independently in a large, phenotypically diverse radiation of songbirds

The concept of a macroevolutionary trade-off among sexual signals has a storied history in evolutionary biology. Theory predicts that if multiple sexual signals are costly for males to produce or maintain and females prefer a single, sexually selected trait, then an inverse correlation between sexual signal elaborations is expected among species. However, empirical evidence for what has been termed the \u27transfer hypothesis\u27 is mixed, which may reflect different selective pressures among lineages, evolutionary covariates or methodological differences among studies. Here,we examine interspecific correlations between song and plumage elaboration in a phenotypically diverse, widespread radiation of songbirds, the tanagers. The tanagers (Thraupidae) are the largest family of songbirds, representing nearly 10% of all songbirds. We assess variation in song and plumage elaboration across 301 species, representing the largest scale comparative study of multimodal sexual signalling to date. We consider whether evolutionary covariates, including habitat, structural and carotenoid-based coloration, and subfamily groupings influence the relationship between song and plumage elaboration. We find that song and plumage elaboration are uncorrelated when considering all tanagers, although the relationship between song and plumage complexity varies among subfamilies. Taken together, we find that elaborate visual and vocal sexual signals evolve independently among tanagers. © 2014 The Authors Published by the Royal Society. All rights reserved

Comparison of Target-Capture and Restriction-Site Associated DNA Sequencing for Phylogenomics: A Test in Cardinalid Tanagers (Aves, Genus: Piranga)

This is a pre-copyedited, author-produced version of an article accepted for publication in Systematic Biology following peer review. The version of record, Joseph D. Manthey, Luke C. Campillo, Kevin J. Burns, Robert G. Moyle; Comparison of Target-Capture and Restriction-Site Associated DNA Sequencing for Phylogenomics: A Test in Cardinalid Tanagers (Aves, Genus: Piranga), Systematic Biology, Volume 65, Issue 4, 1 July 2016, Pages 640–650, is available online at: ttps://doi.org/10.1093/sysbio/syw005.Restriction-site associated DNA sequencing (RAD-seq) and target capture of specific genomic regions, such as ultraconserved elements (UCEs), are emerging as two of the most popular methods for phylogenomics using reduced-representation genomic data sets. These two methods were designed to target different evolutionary timescales: RAD-seq was designed for population-genomic level questions and UCEs for deeper phylogenetics. The utility of both data sets to infer phylogenies across a variety of taxonomic levels has not been adequately compared within the same taxonomic system. Additionally, the effects of uninformative gene trees on species tree analyses (for target capture data) have not been explored. Here, we utilize RAD-seq and UCE data to infer a phylogeny of the bird genus Piranga. The group has a range of divergence dates (0.5–6 myr), contains 11 recognized species, and lacks a resolved phylogeny. We compared two species tree methods for the RAD-seq data and six species tree methods for the UCE data. Additionally, in the UCE data, we analyzed a complete matrix as well as data sets with only highly informative loci. A complete matrix of 189 UCE loci with 10 or more parsimony informative (PI) sites, and an approximately 80% complete matrix of 1128 PI single-nucleotide polymorphisms (SNPs) (from RAD-seq) yield the same fully resolved phylogeny of Piranga. We inferred non-monophyletic relationships of Pirangalutea individuals, with all other a priori species identified as monophyletic. Finally, we found that species tree analyses that included predominantly uninformative gene trees provided strong support for different topologies, with consistent phylogenetic results when limiting species tree analyses to highly informative loci or only using less informative loci with concatenation or methods meant for SNPs alone

Physical characteristics and non-keplerian orbital motion of "propeller" moons embedded in Saturn's rings

We report the discovery of several large "propeller" moons in the outer part of Saturn's A ring, objects large enough to be followed over the 5-year duration of the Cassini mission. These are the first objects ever discovered that can be tracked as individual moons, but do not orbit in empty space. We infer sizes up to 1--2 km for the unseen moonlets at the center of the propeller-shaped structures, though many structural and photometric properties of propeller structures remain unclear. Finally, we demonstrate that some propellers undergo sustained non-keplerian orbit motion. (Note: This arXiv version of the paper contains supplementary tables that were left out of the ApJL version due to lack of space).Comment: 9 pages, 4 figures; Published in ApJ

Genetic variation among western populations of the Horned Lark (Eremophila alpestris) indicates recent colonization of the Channel Islands off southern California, mainland-bound dispersal, and postglacial range shifts

© 2014 American Ornithologists\u27 Union. The Channel Islands off the coast of southern California host \u3e50 species of terrestrial vertebrates with varying degrees of phenotypic differentiation. However, most organisms that breed on the Channel Islands remain unstudied with respect to genetic differentiation from mainland populations. By comparing patterns of genetic variation between the Channel Islands and the mainland, we aimed to further our understanding of the role that the Channel Islands have played in diversification of the North American biota. We evaluated long-standing, untested hypotheses regarding colonization patterns and evolutionary relationships among western populations of the Horned Lark (Eremophila alpestris), including the endemic Channel Island subspecies E. a. insularis. We also examined how many times Horned Larks have colonized the Channel Islands, whether the species exhibits asymmetrical patterns of gene flow between mainland and island populations, and whether E. a. strigata of the Pacific Northwest is closely related to the phenotypically similar, but geographically separated, island subspecies. We found that E. a. insularis is polyphyletic, which suggests either multiple colonization events from the mainland or incomplete lineage sorting of a large ancestral population. We also inferred higher rates of migration from the Channel Islands to the mainland, with E. a. strigata being closely related to individuals from the Channel Islands and coastal southern California. Moreover, ecological niche models for E. a. strigata identified suitable abiotic conditions in southern California and the Pacific Northwest during the Last Glacial Maximum, which suggests that E. a. strigata experienced a postglacial range shift in addition to a population bottleneck. Our results provide novel insight regarding the origins of the Channel Island avifauna and the evolutionary history of the Horned Lark in the western United States. Moreover, our findings suggest that Channel Island birds may be weakly differentiated from mainland populations despite phenotypic differences between recognized subspecies