Whole-genome sequence analysis shows that two endemic species of North American wolf are admixtures of the coyote and gray wolf.

Protection of populations comprising admixed genomes is a challenge under the Endangered Species Act (ESA), which is regarded as the most powerful species protection legislation ever passed in the United States but lacks specific provisions for hybrids. The eastern wolf is a newly recognized wolf-like species that is highly admixed and inhabits the Great Lakes and eastern United States, a region previously thought to be included in the geographic range of only the gray wolf. The U.S. Fish and Wildlife Service has argued that the presence of the eastern wolf, rather than the gray wolf, in this area is grounds for removing ESA protection (delisting) from the gray wolf across its geographic range. In contrast, the red wolf from the southeastern United States was one of the first species protected under the ESA and was protected despite admixture with coyotes. We use whole-genome sequence data to demonstrate a lack of unique ancestry in eastern and red wolves that would not be expected if they represented long divergent North American lineages. These results suggest that arguments for delisting the gray wolf are not valid. Our findings demonstrate how a strict designation of a species under the ESA that does not consider admixture can threaten the protection of endangered entities. We argue for a more balanced approach that focuses on the ecological context of admixture and allows for evolutionary processes to potentially restore historical patterns of genetic variation

Characterization of High-Power Rocket and Jet Noise Using Near-Field Acoustical Holography

Structural fatigue, hearing damage, and community disturbances are all consequences of rocket and jet noise, especially as they become more powerful. Noise-reduction schemes require accurate characterization of the noise sources within rocket plumes and jets. Nearfield acoustical holography (NAH) measurements were made to visualize the sound field in the jet exhaust region of an F-22 Raptor. This is one of the largest-scale applications of NAH since its development in the 1980s. A scan-based holographic measurement was made using a 90-microphone array with 15 cm regular grid spacing, for four engine power settings. The array was scanned through 93 measurement positions, along three different planes in a region near 7 m from the jet centerline and 23 m downstream. In addition, 50 fixed reference microphones were placed along the ground 11.6 m from the jet centerline, spanning 30.8 m. The reference microphones have been used to perform virtual coherence on the measurement planes. Statistically-optimized NAH (SONAH) has been used to backpropagate the sound field to the source region for low frequencies, and to identify jet noise characteristics. Ground reflection interference and other non-ideal measurement conditions must be dealt with. Details relating to jet coherence lengths and their relation to reference microphone requirements will be discussed. Preliminary results of this ongoing work will be presented. [Work supported by Air Force SBIR.

Characterization of Rocket and Jet Noise using Near-Field Acoustic Holography Methods

As rockets and jets on military aircraft become more powerful, the noise they produce can lead to structural fatigue, hearing damage, and community disturbances. Noise-reduction technologies and sound radiation prediction require accurate characterization of the noise sources within rocket plumes and jets. Near-field acoustical holography techniques were used to visualize the sound field in the region of the jet exhaust on a high-performance military jet. Holography requires a coherent measurement of the sound field, but the size of the jet made a dense measurement over the entire source region impractical. Thus, a scan-based measurement was performed, after which a partial field decomposition (PFD) procedure was used to tie together incoherent scans. Then, the effective aperture of the measurement was extended utilizing the rigid ground reflection and a processing technique called analytic continuation. Finally, the three-dimensional sound field was reconstructed using statistically-optimized near-field acoustical holography (SONAH). This is the first time such a map has been obtained for a full-scale military aircraft. [Work supported by Air Force SBIR.

New U–Pb Geochronology for the Central Atlantic Magmatic Province, Critical Reevaluation of High-Precision Ages and Their Impact on the End-Triassic Extinction Event

The end-Triassic extinction (ETE) event represents one of the ‘big five’ episodes of mass extinction. The leading hypothesis for the cause of the ETE is the intrusion of voluminous magmas of the Central Atlantic Magmatic Province (CAMP) into carbon-rich sediments of two South American sedimentary basins, around 201.5 Ma. The timing of dikes and sills emplacement, however, must be considered in light of age models from CAMP rocks occurring in North America. In this work, we present new high-precision ages for critical samples in NE Brazil (201.579 ± 0.057 Ma) and Canada (201.464 ± 0.017 Ma), in order to evaluate how the South and North American magmatic events compare at the 100-ka level, and to the ETE timing. We also discuss inter-laboratory reproducibility of high-precision CAMP ages, including the 230Th disequilibrium corrections that are made to zircon U–Pb dates. Our findings in this newly discovered extension of the CAMP large igneous province in NE Brazil support the hypothesis that the CAMP may be responsible for the ETE through the triggering of greenhouse gas release from magma-evaporite interactions (contact metamorphism) in the South American basins

Canonical Melnikov theory for diffeomorphisms

We study perturbations of diffeomorphisms that have a saddle connection between a pair of normally hyperbolic invariant manifolds. We develop a first-order deformation calculus for invariant manifolds and show that a generalized Melnikov function or Melnikov displacement can be written in a canonical way. This function is defined to be a section of the normal bundle of the saddle connection. We show how our definition reproduces the classical methods of Poincar\'{e} and Melnikov and specializes to methods previously used for exact symplectic and volume-preserving maps. We use the method to detect the transverse intersection of stable and unstable manifolds and relate this intersection to the set of zeros of the Melnikov displacement.Comment: laTeX, 31 pages, 3 figure

3q26 Amplification is Rarely Present in Women Whose LSIL Cytology does not Represent CIN 2+ Disease

Comparative Medicine - OneHealth and Comparative Medicine Poster SessionObjective: 10-17% of women with LSIL cytology truly have CIN 2+ disease at colposcopically directed biopsy and 20% of the CIN 2+ lesions derive from women with LSIL cytology. No molecular marker has yet been able to triage LSIL cytology effectively. If possible, the triage would spare women the referral to colposcopy. Irreversible chromosomal damage occurs during oncogenesis. Increasing cervical dysplastic severity occurs with increasing amplification of the 3q26 chromosomal region. The purpose of this study is to evaluate the test characteristics of 3q26 amplification in women whose routine cytology is reported as LSIL with emphasis on the negative predictive value for reassurance. Methods: We conducted a retrospective study using the available SurePath™ liquid cytology LSIL archival samples from women 17-59 years old which were linked to colposcopically directed biopsy samples taken on average 36 days after cytology sampling (3-90 day range). Nuclei from the LSIL samples were hybridized with a single-copy probe for the chromosome 3q26 region and a control probe for the centromeric alpha repeat sequence of chromosome 7, using standard FISH methods. Amplification was defined as five or more signals present in at least 2 cells. Results: Of the 68 paired cytology/biopsy samples, 3q26 amplification occurred in 40% of the women with CIN 2+ disease (sensitivity 95% CI: 12, 74). There was no amplification in 91% of women with less than CIN 2 disease (specificity 95% CI: 81, 97); and the negative predictive value was 90% (79, 96). Conclusions: The lack of 3q26 amplification in women with screening cytology LSIL results offers reassurance that CIN 2+ disease has not developed. Future prospective studies are ongoing

Recent Progress on Nonlinear Ultrasonic Testing for Materials Aging in Nuclear Applications

Materials in nuclear power plants are subjected to a variety of time-dependent aging phenomena, depending on their environmental conditions. In many cases, such phenomena cause microstructural changes in the materials before the development of macro scale damage or, eventually, component failure. Nonlinear ultrasonic testing has the potential to probe microstructural characteristics of materials that have undergone aging related changes and can potentially be used to establish structure-property relationships or predict where macro scale damage (e.g., cracking) is likely to occur. In this talk, recent work relating measured material nonlinearity to microstructural changes encountered in nuclear power applications is presented, specifically radiation damage in ferritic steels and weld sensitization in austenitic stainless steels. In the case of radiation damage, it has been established that the formation of BCC Cu nanoprecipitates and changes in dislocation density affect the material nonlinearity. In nonlinearity measurements in the case of weld sensitization (migration of Cr to grain boundaries in the heat affected zone, affecting the local corrosion resistance), it is thought formation of M23C6 carbides at the grain boundaries affects the measured material nonlinearity. Preliminary results are presented

Value-based decision-making of cigarette and nondrug rewards in dependent and occasional cigarette smokers:An FMRI study

Little is known about the neural functioning that underpins drug valuation and choice in addiction, including nicotine dependence. Following ad libitum smoking, 19 dependent smokers (smoked≥10/day) and 19 occasional smokers (smoked 0.5‐5/week) completed a decision‐making task. First, participants stated how much they were willing‐to‐pay for various amounts of cigarettes and shop vouchers. Second, during functional magnetic resonance imaging, participants decided if they wanted to buy these cigarettes and vouchers for a set amount of money. We examined decision‐making behaviour and brain activity when faced with cigarette and voucher decisions, purchasing (vs not purchasing) cigarettes and vouchers, and “value signals” where brain activity correlated with cigarette and voucher value. Dependent smokers had a higher willingness‐to‐pay for cigarettes and greater activity in the bilateral middle temporal gyrus when faced with cigarette decisions than occasional smokers. Across both groups, the decision to buy cigarettes was associated with activity in the left paracingulate gyrus, right nucleus accumbens, and left amygdala. The decision to buy vouchers was associated with activity in the left superior frontal gyrus, but dependent smokers showed weaker activity in the left posterior cingulate gyrus than occasional smokers. Across both groups, cigarette value signals were observed in the left striatum and ventromedial prefrontal cortex. To summarise, nicotine dependence was associated with greater behavioural valuation of cigarettes and brain activity during cigarette decisions. When purchasing cigarettes and vouchers, reward and decision‐related brain regions were activated in both groups. For the first time, we identified value signals for cigarettes in the brain