Using the Big Ideas in Cosmology to Teach College Students

Recent advances in our understanding of the Universe have revolutionized our view of its structure, composition and evolution. However, these new ideas have not necessarily been used to improve the teaching of introductory astronomy students. In this project, we have conducted research into student understanding of cosmological ideas so as to develop effective web-based tools to teach basic concepts important to modern cosmology. The tools are intended for use at the introductory college level. Our research uses several instruments, including open-ended and multiple choice surveys conducted at multiple institutions, as well as interviews and course artifacts at one institution, to ascertain what students know regarding modern cosmological ideas, what common misunderstandings and misconceptions they entertain, and what sorts of materials can most effectively overcome student difficulties in learning this material. These data are being used to create a suite of interactive, web-based tutorials that address the major ideas in cosmology using real data. Having students engage with real data is a powerful means to help students overcome certain misconceptions. Students master the scientific concepts and reasoning processes that lead to our current understanding of the universe through interactive tasks, prediction and reflection, experimentation, and model building.Comment: 2012 Fermi Symposium proceedings - eConf C12102

The Imprint of Gravitational Waves in Models Dominated by a Dynamical Cosmic Scalar Field

An alternative to the standard cold dark matter model has been recently proposed in which a significant fraction of the energy density of the universe is due to a dynamical scalar field ($Q$) whose effective equation-of-state differs from that of matter, radiation or cosmological constant ($\Lambda$). In this paper, we determine how the Q-component modifies the primordial inflation gravitational wave (tensor metric) contribution to the cosmic microwave background anisotropy and, thereby, one of the key tests of inflation.Comment: 15 pages, 14 figures, revtex, submitted to Phys. Rev.

Dynamical Lambda Models of Structure Formation

Models of structure formation with a cosmological constant $\Lambda$ provide a good fit to the observed power spectrum of galaxy clustering. However, they suffer from several problems. Theoretically, it is difficult to understand why the cosmological constant is so small in Planck units. Observationally, while the power spectra of cold dark matter plus $\Lambda$ models have approximately the right shape, the COBE-normalized amplitude for a scale invariant spectrum is too high, requiring galaxies to be anti-biased relative to the mass distribution. Attempts to address the first problem have led to models in which a dynamical field supplies the vacuum energy, which is thereby determined by fundamental physics scales. We explore the implications of such dynamical $\Lambda$ models for the formation of large-scale structure. We find that there are dynamical models for which the amplitude of the COBE-normalized spectrum matches the observations. We also calculate the cosmic microwave background anisotropies in these models and show that the angular power spectra are distinguishable from those of standard cosmological constant models.Comment: 25 pages, latex, 9 figures. Also available by WWW at http://www-astro-theory.fnal.gov/ under Publication

Ian Trowell photograph, Codsall Fair, 2002.

Tony Cotton's Twist photographed 6 May 2002. TW13

Evaluation of Modified Yfiler™ Amplification Strategy for Compromised Samples

amplification protocol for the AmpFSTR® Yfiler™ PCR Amplification Kit (Applied Biosystems) and explore the potential of Y-chromosomal short tandem repeat (Y-STR) recovery from severely degraded skeletal remains encountered at the Armed Forces DNA Identification Laboratory. Methods Experiments were performed using two sets of Yfiler™ amplification parameters. One set of parameters reflected the manufacturer’s recommendations. The second set of parameters included twice the recommended Taq concentration and 6 additional cycles. Recovery of authentic alleles and the incidence of drop-in alleles were assessed for 3 data sets: 8 different quantities of pristine DNA, 8 artificially-degraded samples, and 31 non-probative case samples. Results Samples tested with both protocols from all 3 data sets yielded twice as many authentic alleles under the modified parameters than under the standard parameters (62% vs 31%), with only a nominal associated increase in the occurrence of non-authentic alleles (1.36% of all alleles detected). When applied to a range of representative casework samples, the modified protocol leveraged 9 or more reproducible alleles from over half of the specimens tested. Conclusion Reproducible and informative Y-STR profiles can be recovered from a broad range of degraded and inhibited skeletal remains extracts when a commercially available kit is employed under modified amplification parameters

A randomized, controlled field study to assess the efficacy and safety of lotilaner flavored chewable tablets (Credelio™) in eliminating fleas in client-owned dogs in the USA

Abstract Background Preclinical studies have shown that the novel isoxazoline, lotilaner (Credelio™, Elanco) administered orally to dogs, produces rapid flea and tick knockdown and sustained speed of kill for at least a month post-treatment with a wide safety margin. A field study was undertaken to validate pre-clinical results. Methods Dogs were enrolled at 10 veterinary clinics across the United States. Qualifying households containing up to three dogs and one primary dog with at least 10 fleas were randomized 2:1 to receive lotilaner (Credelio™, Elanco) at the recommended minimum dose of 20 mg/kg, or afoxolaner (Nexgard®, Merial), administered per label, to give a minimum dose of 2.5 mg/kg. Treatments were dispensed on Days 0, 30 and 60 for administration by owners; all household dogs received the same treatment as the primary dog. Post-enrollment flea and tick counts were made on primary dogs on Days 30, 60 and 90, and all dogs were assessed for tablet palatability and safety. Results For efficacy assessments, data were used from 111 lotilaner-treated dogs and 50 afoxolaner-treated dogs; for safety, 197 and 86 dogs, respectively. Percent reductions from baseline in geometric mean flea counts for the lotilaner group were 99.3, 99.9 and 100% on Days 30, 60 and 90, respectively, and for afoxolaner 98.3, 99.8 and 99.8% (P < 0.001, both groups, all days). On Day 90, 100% of lotilaner-treated dogs and 93% of afoxolaner-treated dogs were flea-free. Too few ticks were present to allow assessment. There were no differences in palatability between products (P = 0.2132), with, respectively, 94% and 96% of lotilaner and afoxolaner treatments accepted when offered by hand, in an empty food bowl or with food. Both treatments were well tolerated, alleviating clinical signs of flea allergy dermatitis (FAD) in dogs affected at enrollment. Conclusion A single owner-administered lotilaner treatment was greater than 99% effective in reducing mean flea counts within 30 days. Three consecutive monthly lotilaner treatments resulted in a 100% reduction in flea infestations, and a substantial reduction in signs of FAD. Lotilaner flavored tablets were readily accepted under field conditions. The absence of treatment-related adverse events confirms the safety of lotilaner in dogs