102 research outputs found

    Mitochondrial DNA evolution in the Anaxyrus boreas species group

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    The Anaxyrus boreas species group currently comprises four species in western North America including the broadly distributed A. boreas, and three localized species, Anaxyrus nelsoni, Anaxyrus exsul and Anaxyrus canorus. Phylogenetic analyses of the mtDNA 12S rDNA, cytochrome oxidase I, control region, and restriction sites data, identified three major haplotype clades. The Northwest clade (NW) includes both subspecies of A. boreas and divergent minor clades in the middle Rocky Mountains, coastal, and central regions of the west and Pacific Northwest. The Southwest (SW) clade includes A. exsul, A. nelsoni, and minor clades in southern California. Anaxyrus canorus, previously identified as paraphyletic, has populations in both the NW and SW major clades. The Eastern major clade (E) includes three divergent lineages from southern Utah, the southern Rocky Mountains, and north of the Great Basin at the border of Utah and Nevada. These results identify new genetic variation in the eastern portion of the toad’s range and are consistent with previous regional studies from the west coast. Low levels of control region sequence divergence between major clades (2.2–4.7% uncorrected pair-wise distances) are consistent with Pleistocene divergence and suggest that the phylogeographic history of the group was heavily influenced by dynamic Pleistocene glacial and climatic changes, and especially pluvial changes, in western North America. Results reported here may impact conservation plans in that the current taxonomy does not reflect the diversity in the group

    Fixed versus Flexible Election Cycles: Explaining innovation in the timing of Canada’s Election Cycle

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    This paper argues that there is an efficiency gain underlying the recent adoption of legislation calling for a fixed four-year governing term by the federal and most provincial governments in Canada. The efficiency gain arises from foreclosing an externality produced by the constitutional provision that sets a maximum length for a legislative term (five years) while allowing the governing party (through the Governor General) to dissolve the House early. Because the opportunistic use of surprise can improve the governing party’s probability of winning, strategic choice can lead to elections being held at times that most disadvantage the incumbent’s rivals. Evidence from Canada is introduced suggesting that federal elections became less predictable through successive reductions in the campaign time given to competitors, thus raising the cost of this externality. The same reasoning suggests that the party most likely to propose this legislative innovation will be the party in opposition rather than in power and/or the new leader of an established party facing loss in the upcoming election. By fulfilling the fixed term even when it could benefit by calling the election early, the party establishes a precedent that raises the political cost to others of cancelling the fixed term legislation

    Nocturnal thoracoabdominal asynchrony in house dust mite-sensitive nonhuman primates

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    Nocturnal bronchoconstriction is a common symptom of asthma in humans, but is poorly documented in animal models. Thoracoabdominal asynchrony (TAA) is a noninvasive clinical indication of airway obstruction. In this study, respiratory inductive plethysmography (RIP) was used to document nocturnal TAA in house dust mite (HDM)-sensitive Cynomolgus macaques. Dynamic compliance (Cdyn) and lung resistance (RL) measured in anesthetized animals at rest and following exposure to HDM allergen, methacholine, and albuterol were highly correlated with three RIP parameters associated with TAA, ie, phase angle of the rib cage and abdomen waveforms (PhAng), baseline effort phase relation (eBPRL) and effort phase relation (ePhRL). Twenty-one allergic subjects were challenged with HDM early in the morning, and eBPRL and ePhRL were monitored for 20 hours after provocation. Fifteen of the allergic subjects exhibited gradual increases in eBPRL and ePhRL between midnight and 6 am, with peak activity at 4 am. However, as in humans, this nocturnal response was highly variable both between subjects and within subjects over time. The results document that TAA in this nonhuman primate model of asthma is highly correlated with Cdyn and RL, and demonstrate that animals exhibiting acute responses to allergen exposure during the day also exhibit nocturnal TAA

    Perspectives and Experiences of Participation by Individuals with Disabilities: An Evidence-Based Practice Project

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    This Evidence-Based Practice (EBP) project considered the following question: How do individuals with disabilities describe their perspectives on and experiences with participation

    A Dynamic Model of Political Party Equilibrium: the evolution of ENP in Canada, 1870 – 2011

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    The effective number of political parties (ENP) in a first-past-the-post single member (SMP) electoral system is analyzed as a dynamic process whereby the tournament nature of the election contest induces excessive entry and sunk entry costs promote persistence even as Duverger-Demsetz type political competition works to winnow unsuccessful minor candidates and parties. The result is a fringe of ever changing marginal parties circulating in long run equilibrium. The factors hypothesized to affect the entry and exit of candidates and parties are analyzed first using an auto-regressive distributed lag (ARDL) model whose advantage is that it allows the separation of an evolving long run equilibrium from short run variations in response to transitory changes in conditioning variables and the process of converging back to the long run equilibrium. The possibility that the short run adjustment process is asymmetric either for parties or candidates is tested using panel estimation techniques. The results are consistent with an observed time path that incorporates slower adjustment to positive as opposed to negative shocks. Variations in the size and trend of both the long and short run are then examined for ENP’s ability to predict changes in the competitiveness of the Canadian federal electoral system

    Reframing Kurtz’s Painting: Colonial Legacies and Minority Rights in Ethnically Divided Societies

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    Minority rights constitute some of the most normatively and economically important human rights. Although the political science and legal literatures have proffered a number of constitutional and institutional design solutions to address the protection of minority rights, these solutions are characterized by a noticeable neglect of, and lack of sensitivity to, historical processes. This Article addresses that gap in the literature by developing a causal argument that explains diverging practices of minority rights protections as functions of colonial governments’ variegated institutional practices with respect to particular ethnic groups. Specifically, this Article argues that in instances where colonial governments politicize and institutionalize ethnic hegemony in the pre-independence period, an institutional legacy is created that leads to lower levels of minority rights protections. Conversely, a uniform treatment and depoliticization of ethnicity prior to independence ultimately minimizes ethnic cleavages post-independence and consequently causes higher levels of minority rights protections. Through a highly structured comparative historical analysis of Botswana and Ghana, this Article builds on a new and exciting research agenda that focuses on the role of long-term historio-structural and institutional influences on human rights performance and makes important empirical contributions by eschewing traditional methodologies that focus on single case studies that are largely descriptive in their analyses. Ultimately, this Article highlights both the strength of a historical approach to understanding current variations in minority rights protections and the varied institutional responses within a specific colonial government

    The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey : measuring DA and H at z = 0.57 from the baryon acoustic peak in the Data Release 9 spectroscopic Galaxy sample

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    We present measurements of the angular diameter distance to and Hubble parameter at z = 0.57 from the measurement of the baryon acoustic peak in the correlation of galaxies from the Sloan Digital Sky Survey III Baryon Oscillation Spectroscopic Survey. Our analysis is based on a sample from Data Release 9 of 264 283 galaxies over 3275 square degrees in the redshift range 0.43 < z < 0.70. We use two different methods to provide robust measurement of the acoustic peak position across and along the line of sight in order to measure the cosmological distance scale. We find DA(0.57) = 1408 ± 45 Mpc and H(0.57) = 92.9 ± 7.8 km s−1 Mpc−1 for our fiducial value of the sound horizon. These results from the anisotropic fitting are fully consistent with the analysis of the spherically averaged acoustic peak position presented in Anderson et al. Our distance measurements are a close match to the predictions of the standard cosmological model featuring a cosmological constant and zero spatial curvature.Publisher PDFPeer reviewe

    Baryon Acoustic Oscillations in the Ly{\alpha} forest of BOSS DR11 quasars

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    We report a detection of the baryon acoustic oscillation (BAO) feature in the flux-correlation function of the Ly{\alpha} forest of high-redshift quasars with a statistical significance of five standard deviations. The study uses 137,562 quasars in the redshift range 2.1z3.52.1\le z \le 3.5 from the Data Release 11 (DR11) of the Baryon Oscillation Spectroscopic Survey (BOSS) of SDSS-III. This sample contains three times the number of quasars used in previous studies. The measured position of the BAO peak determines the angular distance, DA(z=2.34)D_A(z=2.34) and expansion rate, H(z=2.34)H(z=2.34), both on a scale set by the sound horizon at the drag epoch, rdr_d. We find DA/rd=11.28±0.65(1σ)1.2+2.8(2σ)D_A/r_d=11.28\pm0.65(1\sigma)^{+2.8}_{-1.2}(2\sigma) and DH/rd=9.18±0.28(1σ)±0.6(2σ)D_H/r_d=9.18\pm0.28(1\sigma)\pm0.6(2\sigma) where DH=c/HD_H=c/H. The optimal combination, DH0.7DA0.3/rd\sim D_H^{0.7}D_A^{0.3}/r_d is determined with a precision of 2%\sim2\%. For the value rd=147.4 Mpcr_d=147.4~{\rm Mpc}, consistent with the CMB power spectrum measured by Planck, we find DA(z=2.34)=1662±96(1σ) MpcD_A(z=2.34)=1662\pm96(1\sigma)~{\rm Mpc} and H(z=2.34)=222±7(1σ) kms1Mpc1H(z=2.34)=222\pm7(1\sigma)~{\rm km\,s^{-1}Mpc^{-1}}. Tests with mock catalogs and variations of our analysis procedure have revealed no systematic uncertainties comparable to our statistical errors. Our results agree with the previously reported BAO measurement at the same redshift using the quasar-Ly{\alpha} forest cross-correlation. The auto-correlation and cross-correlation approaches are complementary because of the quite different impact of redshift-space distortion on the two measurements. The combined constraints from the two correlation functions imply values of DA/rdD_A/r_d and DH/rdD_H/r_d that are, respectively, 7% low and 7% high compared to the predictions of a flat Λ\LambdaCDM cosmological model with the best-fit Planck parameters. With our estimated statistical errors, the significance of this discrepancy is 2.5σ\approx 2.5\sigma.Comment: Accepted for publication in A&A. 17 pages, 18 figure

    Worldwide Prevalence of Lentivirus Infection in Wild Feline Species: Epidemiologic and Phylogenetic Aspects

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    The natural occurrence of lentiviruses closely related to feline immunodeficiency virus (FIV) in nondomestic felid species is shown here to be worldwide. Cross-reactive antibodies to FIV were common in several free-ranging populations of large cats, including East African lions and cheetahs of the Serengeti ecosystem and in puma (also called cougar or mountain lion) populations throughout North America. Infectious puma lentivirus (PLV) was isolated from several Florida panthers, a severely endangered relict puma subspecies inhabiting the Big Cypress Swamp and Everglades ecosystems in southern Florida. Phylogenetic analysis of PLV genomic sequences from disparate geographic isolates revealed appreciable divergence from domestic cat FIV sequences as well as between PLV sequences found in different North American locales. The level of sequence divergence between PLV and FIV was greater than the level of divergence between human and certain simian immunodeficiency viruses, suggesting that the transmission of FIV between feline species is infrequent and parallels in time the emergence of HIV from simian ancestors

    The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey : baryon acoustic oscillations in the Data Releases 10 and 11 Galaxy samples

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    We present a one per cent measurement of the cosmic distance scale from the detections of the baryon acoustic oscillations (BAO) in the clustering of galaxies from the Baryon Oscillation Spectroscopic Survey, which is part of the Sloan Digital Sky Survey III. Our results come from the Data Release 11 (DR11) sample, containing nearly one million galaxies and covering approximately 8500 square degrees and the redshift range 0.2 < z < 0.7. We also compare these results with those from the publicly released DR9 and DR10 samples. Assuming a concordance Λ cold dark matter (ΛCDM) cosmological model, the DR11 sample covers a volume of 13 Gpc3 and is the largest region of the Universe ever surveyed at this density. We measure the correlation function and power spectrum, including density-field reconstruction of the BAO feature. The acoustic features are detected at a significance of over 7σ in both the correlation function and power spectrum. Fitting for the position of the acoustic features measures the distance relative to the sound horizon at the drag epoch, rd, which has a value of rd,fid = 149.28 Mpc in our fiducial cosmology. We find DV = (1264 ± 25 Mpc)(rd/rd,fid) at z = 0.32 and DV = (2056 ± 20 Mpc)(rd/rd,fid) at z = 0.57. At 1.0 per cent, this latter measure is the most precise distance constraint ever obtained from a galaxy survey. Separating the clustering along and transverse to the line of sight yields measurements at z = 0.57 of DA = (1421 ± 20 Mpc)(rd/rd,fid) and H = (96.8 ± 3.4 km s−1 Mpc−1)(rd,fid/rd). Our measurements of the distance scale are in good agreement with previous BAO measurements and with the predictions from cosmic microwave background data for a spatially flat CDM model with a cosmological constant.Publisher PDFPeer reviewe
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