Saint Anselm College

About: Saint Anselm College is a education organization based out in Manchester, New Hampshire, United States. It is known for research contribution in the topics: Politics & Nurse education. The organization has 255 authors who have published 522 publications receiving 7222 citations.

Macrogeographic variation in the song of the Mourning Warbler (Oporornis philadelphia)

Abstract: Studies of macrogeographic variation in birdsong involve populations incapable of interbreeding because of physical barriers or separation by large distances. Different patterns have emerged from t...

Constraining Polarized Foregrounds for EoR Experiments I: 2D Power Spectra from the PAPER-32 Imaging Array

Abstract: Current-generation low frequency interferometers constructed with the objective of detecting the high-redshift 21 cm background, aim to generate power spectra of the brightness-temperature contrast of neutral hydrogen in primordial intergalactic medium. Two-dimensional power spectra (power in Fourier modes parallel and perpendicular to the line of sight) formed from interferometric visibilities have been shown to delineate a boundary between spectrally-smooth foregrounds (known as the wedge) and spectrally-structured 21 cm background emission (the EoR-window). However, polarized foregrounds are known to possess spectral structure due to Faraday rotation, which can leak into the EoR window. In this work, we create and analyze 2D power spectra from the PAPER-32 imaging array in Stokes I, Q, U and V. These allow us to observe and diagnose systematic effects in our calibration at high signal-to-noise within the Fourier space most relevant to EoR experiments. We observe well-defined windows in the Stokes visibilities, with Stokes Q, U and V power spectra sharing a similar wedge shape to that seen in Stokes I. With modest polarization calibration, we see no evidence that polarization calibration errors move power outside the wedge in any Stokes visibility, to the noise levels attained. Deeper integrations will be required to confirm that this behavior persists to the depth required for EoR detection.

Macrogeographic variation in song of the MacGillivray's Warbler (Geothlypis tolmiei)

Abstract: Geographic variation in mating signals is of interest to evolutionary biologists because the consequences of spatial divergence may lead to behavioral discrimination, assortative mating, and speciation Birdsong is a mating signal of songbirds, and geographic variation in the form of small-scale dialects or large-scale regiolects has been documented in many species We studied macrogeographic variation in song of the MacGillivray's Warbler (Geothlypis tolmiei) to determine the pattern of song variation in this species Hypotheses used to explain the evolution of song divergence were also examined We found extensive individual variation in the cultural units and physical parameters of song that overwhelmed differences among populations We did not find dialects in the breeding range but did find a pattern of clinal variation with song differences increasing with increasing geographic distances among populations Hypotheses that explain patterns of song divergence in other species did not apply to