272 research outputs found

    Patterns of Extinction Risk and Threat for Marine Vertebrates and Habitat-Forming Species in the Tropical Eastern Pacific

    Get PDF
    Marine conservation activities around the globe are largely undertaken in the absence of comprehensive species-specific information. To address this gap, complete regional species assemblages of major marine taxa are being progressively assessed against the Categories and Criteria of the International Union for the Conservation of Nature (IUCN) Red List of Threatened Species. The present study is the first analysis of entire major components of the biota of a large marine biogeographic region conducted in the Tropical Eastern Pacific (TEP). It is based on recently completed IUCN Red List assessments for all known species of bony and cartilaginous shorefishes, corals, mangroves, and seagrasses in the TEP. Twelve percent of the \u3e1600 species assessed are in threatened categories, indicative of elevated extinction risk. Spatial analysis of all assessed taxonomic groups, including previous IUCN Red List assessments for seabirds, marine mammals, and marine turtles, highlights specific geographical areas of elevated threatenedspecies richness. The distribution of threatened species in the TEP is primarily linked to areas with high rates of overfishing, habitat loss, and increasing El NiΓ±o-Southern Oscillation (ENSO) event impacts, as well as oceanic islands with high stochastic risk factors for endemic species. Species assigned to the highest threat categories have life history traits that likely decrease their resilience to various regional and site-specific threats. Comprehensive information in the form of IUCN Red List assessments combined with spatial analysis will greatly help to refine both site- and species-specific marine conservation priorities in the TEP

    Algebraic characterization of X-states in quantum information

    Get PDF
    A class of two-qubit states called X-states are increasingly being used to discuss entanglement and other quantum correlations in the field of quantum information. Maximally entangled Bell states and "Werner" states are subsets of them. Apart from being so named because their density matrix looks like the letter X, there is not as yet any characterization of them. The su(2) X su(2) X u(1) subalgebra of the full su(4) algebra of two qubits is pointed out as the underlying invariance of this class of states. X-states are a seven-parameter family associated with this subalgebra of seven operators. This recognition provides a route to preparing such states and also a convenient algebraic procedure for analytically calculating their properties. At the same time, it points to other groups of seven-parameter states that, while not at first sight appearing similar, are also invariant under the same subalgebra. And it opens the way to analyzing invariant states of other subalgebras in bipartite systems.Comment: 4 pages, 1 figur

    The Lantern Vol. 52, No. 2, Spring 1986

    Get PDF
    β€’ The Cartoonist β€’ Balance β€’ Haiku β€’ Moment of Truth β€’ There Was a Man β€’ Mad Song / Cassandra\u27s Song β€’ Part I - The Descent β€’ Political Thought β€’ Beast β€’ Questions Yet Unanswered β€’ Aphrodite: A Lover\u27s Lament β€’ The Most Limber Boy β€’ Style And β€’ Thoughts From My Confusion β€’ Andy β€’ Momma Wake Up β€’ In The Suburbs β€’ Tommy β€’ When the Phone Rings β€’ There\u27s Something Soothing β€’ Starting Over β€’ A Day in the Life of a Flower β€’ Pretension β€’ It Seems Like So Long Ago β€’ I Walk Along β€’ Insignificant Man β€’ Variations on a Latin Theme β€’ The Riddle β€’ Roll the Dice - Its Your Turn β€’ This Is Your Day β€’ One Night Stand β€’ Make My Day β€’ You Really Can\u27t Expect β€’ Medusa β€’ Don\u27t Think β€’ Broken Chain β€’ Life...A Hammock? β€’ To My Friend β€’ Ode On a Grecian Keghttps://digitalcommons.ursinus.edu/lantern/1128/thumbnail.jp

    Factors Associated with Preoperative Magnetic Resonance Imaging Use among Medicare Beneficiaries with Nonmetastatic Breast Cancer

    Get PDF
    Preoperative breast magnetic resonance imaging (MRI) use among Medicare beneficiaries with breast cancer has substantially increased from 2005 to 2009. We sought to identify factors associated with preoperative breast MRI use among women diagnosed with ductal carcinoma in situ (DCIS) or stage I-III invasive breast cancer (IBC)

    Breast MRI in the Diagnostic and Preoperative Workup Among Medicare Beneficiaries With Breast Cancer

    Get PDF
    We compared the frequency and sequence of breast imaging and biopsy use for the diagnostic and preoperative workup of breast cancer according to breast MRI use among older women

    Metabolic profiles derived from residual blood spot samples: A longitudinal analysis [version 1; referees: 2 approved]

    Get PDF
    Background: Secondary use of newborn screening dried blood spot samples include use for biomedical or epidemiological research. However, the effects of storage conditions on archival samples requires further examination. The objective of this study was to determine the utility of residual newborn samples for deriving reliable metabolic gestational age estimates. Methods: Residual newborn dried blood spot samples that had been stored for 2-, 4-, 6-, or 12-months in temperature controlled (21Β°C) conditions were re-analyzed for the full panel of newborn screening analytes offered by a provincial newborn screening lab in Ottawa, Canada. Data from re-analyzed samples were compared to corresponding baseline newborn screening values for absolute agreement, and Pearson and intraclass correlation. Performance of a gestational age estimation algorithm originally developed from baseline newborn screening values was then validated on data derived from stored samples. Results: A total of 307 samples were used for this study. 17-hydroxyprogesterone and newborn hemoglobin profiles measured by immunoassay and high-performance liquid chromatography, respectively, were among the most stable markers across all time points of analysis. Acylcarnitines exhibited the greatest degree of variation in stability upon repeat measurement. The largest shifts in newborn analyte profiles and the poorest performance of metabolic gestational age algorithms were observed when samples were analyzed 12-months after sample collection. Conclusions: Duration of sample storage, independent of temperature and humidity, affects newborn screening profiles and gestational age estimates derived from metabolic gestational dating algorithms. When considering use of dried blood spot samples either for clinical or research purposes, care should be taken when interpreting data stemming from secondary use

    ABCB1 (MDR1) polymorphisms and ovarian cancer progression and survival: A comprehensive analysis from the Ovarian Cancer Association Consortium and The Cancer Genome Atlas

    Get PDF
    <b>Objective</b> <i>ABCB1</i> encodes the multi-drug efflux pump P-glycoprotein (P-gp) and has been implicated in multi-drug resistance. We comprehensively evaluated this gene and flanking regions for an association with clinical outcome in epithelial ovarian cancer (EOC).<p></p> <b>Methods</b> The best candidates from fine-mapping analysis of 21 <i>ABCB1</i> SNPs tagging C1236T (rs1128503), G2677T/A (rs2032582), and C3435T (rs1045642) were analysed in 4616 European invasive EOC patients from thirteen Ovarian Cancer Association Consortium (OCAC) studies and The Cancer Genome Atlas (TCGA). Additionally we analysed 1,562 imputed SNPs around ABCB1 in patients receiving cytoreductive surgery and either β€˜standard’ first-line paclitaxel–carboplatin chemotherapy (n = 1158) or any first-line chemotherapy regimen (n = 2867). We also evaluated ABCB1 expression in primary tumours from 143 EOC patients.<p></p> <b>Result</b> Fine-mapping revealed that rs1128503, rs2032582, and rs1045642 were the best candidates in optimally debulked patients. However, we observed no significant association between any SNP and either progression-free survival or overall survival in analysis of data from 14 studies. There was a marginal association between rs1128503 and overall survival in patients with nil residual disease (HR 0.88, 95% CI 0.77–1.01; p = 0.07). In contrast, <i>ABCB1</i> expression in the primary tumour may confer worse prognosis in patients with sub-optimally debulked tumours.<p></p> <b>Conclusion</b> Our study represents the largest analysis of <i>ABCB1</i> SNPs and EOC progression and survival to date, but has not identified additional signals, or validated reported associations with progression-free survival for rs1128503, rs2032582, and rs1045642. However, we cannot rule out the possibility of a subtle effect of rs1128503, or other SNPs linked to it, on overall survival.<p></p&gt

    Telomere disruption results in non-random formation of de novo dicentric chromosomes involving acrocentric human chromosomes

    Get PDF
    Copyright: Β© 2010 Stimpson et al.Genome rearrangement often produces chromosomes with two centromeres (dicentrics) that are inherently unstable because of bridge formation and breakage during cell division. However, mammalian dicentrics, and particularly those in humans, can be quite stable, usually because one centromere is functionally silenced. Molecular mechanisms of centromere inactivation are poorly understood since there are few systems to experimentally create dicentric human chromosomes. Here, we describe a human cell culture model that enriches for de novo dicentrics. We demonstrate that transient disruption of human telomere structure non-randomly produces dicentric fusions involving acrocentric chromosomes. The induced dicentrics vary in structure near fusion breakpoints and like naturally-occurring dicentrics, exhibit various inter-centromeric distances. Many functional dicentrics persist for months after formation. Even those with distantly spaced centromeres remain functionally dicentric for 20 cell generations. Other dicentrics within the population reflect centromere inactivation. In some cases, centromere inactivation occurs by an apparently epigenetic mechanism. In other dicentrics, the size of the alpha-satellite DNA array associated with CENP-A is reduced compared to the same array before dicentric formation. Extrachromosomal fragments that contained CENP-A often appear in the same cells as dicentrics. Some of these fragments are derived from the same alpha-satellite DNA array as inactivated centromeres. Our results indicate that dicentric human chromosomes undergo alternative fates after formation. Many retain two active centromeres and are stable through multiple cell divisions. Others undergo centromere inactivation. This event occurs within a broad temporal window and can involve deletion of chromatin that marks the locus as a site for CENP-A maintenance/replenishment.This work was supported by the Tumorzentrum Heidelberg/Mannheim grant (D.10026941)and by March of Dimes Research Foundation grant #1-FY06-377 and NIH R01 GM069514

    Locoregional treatment of breast cancer in women with and without preoperative magnetic resonance imaging

    Get PDF
    Preoperative magnetic resonance imaging (MRI) use has increased among older women diagnosed with breast cancer. MRI detects additional malignancy, but its impact on locoregional surgery and radiation treatment remains unclear

    Scintillation-limited photometry with the 20-cm NGTS telescopes at Paranal Observatory

    Get PDF
    Ground-based photometry of bright stars is expected to be limited by atmospheric scintillation, although in practice observations are often limited by other sources of systematic noise. We analyse 122 nights of bright star (Gmag ≲ 11.5) photometry using the 20-cm telescopes of the Next-Generation Transit Survey (NGTS) at the Paranal Observatory in Chile. We compare the noise properties to theoretical noise models and we demonstrate that NGTS photometry of bright stars is indeed limited by atmospheric scintillation. We determine a median scintillation coefficient at the Paranal Observatory of CY=1.54⁠, which is in good agreement with previous results derived from turbulence profiling measurements at the observatory. We find that separate NGTS telescopes make consistent measurements of scintillation when simultaneously monitoring the same field. Using contemporaneous meteorological data, we find that higher wind speeds at the tropopause correlate with a decrease in long-exposure (t = 10 s) scintillation. Hence, the winter months between June and August provide the best conditions for high-precision photometry of bright stars at the Paranal Observatory. This work demonstrates that NGTS photometric data, collected for searching for exoplanets, contains within it a record of the scintillation conditions at Paranal
    • …
    corecore