206 research outputs found

    Near Infrared Spectra and Intrinsic Luminosities of Candidate Type II Quasars at 2 < z < 3.4

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    We present JHK near-infrared (NIR) spectroscopy of 25 candidate Type II quasars selected from the Sloan Digital Sky Survey, using Triplespec on the Apache Point Observatory 3.5m telescope, FIRE at the Magellan/Baade 6.5m telescope, and GNIRS on Gemini. At redshifts of 2 < z < 3.4, our NIR spectra probe the rest-frame optical region of these targets, which were initially selected to have strong lines of CIV and Ly alpha, with FWHM<2000 km/s from the SDSS pipeline. We use the [OIII]5007 line shape as a model for the narrow line region emission, and find that \halpha\ consistently requires a broad component with FWHMs ranging from 1000 to 7500 km/s. Interestingly, the CIV lines also require broad bases, but with considerably narrower widths of 1000 to 4500 km/s. Estimating the extinction using the Balmer decrement and also the relationship in lower-z quasars between rest equivalent width and luminosity in the [OIII] line, we find typical A_V values of 0-2 mag, which naturally explain the attenuated CIV lines relative to Halpha. We propose that our targets are moderately obscured quasars. We also describe one unusual object with three distinct velocity peaks in its [OIII] spectrum.Comment: Accepted for publication in ApJ, 18 pages, 14 figure

    Sixty Years of CA: A Cancer Journal for Clinicians

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    The first issue of CA: A Cancer Journal for Clinicians was published in November of 1950. On the 60th anniversary of that date, we briefly review several seminal contributions to oncology and cancer control published in our journal during its first decade. CA Cancer J Clin 2010. © 2010 American Cancer Society, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78301/1/20088_ftp.pd

    Synchronisation of apical constriction and cell cycle progression is a conserved behaviour of pseudostratified neuroepithelia informed by their tissue geometry

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    Neuroepithelial cells balance tissue growth requirement with the morphogenetic imperative of closing the neural tube. They apically constrict to generate mechanical forces which elevate the neural folds, but are thought to apically dilate during mitosis. However, we previously reported that mitotic neuroepithelial cells in the mouse posterior neuropore have smaller apical surfaces than non-mitotic cells. Here, we document progressive apical enrichment of non-muscle myosin-II in mitotic, but not non-mitotic, neuroepithelial cells with smaller apical areas. Live-imaging of the chick posterior neuropore confirms apical constriction synchronised with mitosis, reaching maximal constriction by anaphase, before division and re-dilation. Mitotic apical constriction amplitude is significantly greater than interphase constrictions. To investigate conservation in humans, we characterised early stages of iPSC differentiation through dual SMAD-inhibition to robustly produce pseudostratified neuroepithelia with apically enriched actomyosin. These cultured neuroepithelial cells achieve an equivalent apical area to those in mouse embryos. iPSC-derived neuroepithelial cells have large apical areas in G2 which constrict in M phase and retain this constriction in G1/S. Given that this differentiation method produces anterior neural identities, we studied the anterior neuroepithelium of the elevating mouse mid-brain neural tube. Instead of constricting, mid-brain mitotic neuroepithelial cells have larger apical areas than interphase cells. Tissue geometry differs between the apically convex early midbrain and flat posterior neuropore. Culturing human neuroepithelia on equivalently convex surfaces prevents mitotic apical constriction. Thus, neuroepithelial cells undergo high-amplitude apical constriction synchronised with cell cycle progression but the timing of their constriction if influenced by tissue geometry

    Hematopoietic Cell Transplantation as Curative Therapy for Idiopathic Myelofibrosis, Advanced Polycythemia Vera, and Essential Thrombocythemia

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    AbstractA total of 104 patients, aged 18 to 70 years, with a diagnosis of chronic idiopathic myelofibrosis (CIMF), polycythemia vera (PV), or essential thrombocythemia (ET) with marrow fibrosis were transplanted from allogeneic (56 related and 45 unrelated) or syngeneic (n = 3) donors. Busulfan (BU) or total body irradiation (TBI)-based myeloablative conditioning regimens were used in 95 patients, and a nonmyeloablative regimen of fludarabine plus TBI was used in 9 patients. The source of stem cells was bone marrow in 43 patients and peripheral blood in 61 patients. A total of 63 patients were alive at a follow-up of 1.3–15.2 years (median, 5.3 years), for an estimated 7-year actuarial survival rate of 61%. Eleven patients had recurrent/persistent disease, of whom 8 died. Nonrelapse mortality was 34% at 5 years. Patients conditioned with targeted BU (plasma levels 800–900 ng/mL) plus cyclophosphamide (tBUCY) had a higher probability of survival (68%) than other patients. Dupriez score, platelet count, patient age, and comorbidity score were statistically significantly associated with mortality in univariate models. In a multivariable regression model, use of tBUCY (P = .03), high platelet count at transplantation (P = .01 for PV/ET; P = .39 for other diagnoses), younger patient age (P = .04), and decreased comorbidity score (P = .03) remained statistically significant for improved survival. Our findings show that hematopoietic cell transplantation offers potentially curative treatment for patients with ICMF, PV, or ET

    Can Sophie's Choice Be Adequately Captured by Cold Computation of Minimizing Losses? An fMRI Study of Vital Loss Decisions

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    The vast majority of decision-making research is performed under the assumption of the value maximizing principle. This principle implies that when making decisions, individuals try to optimize outcomes on the basis of cold mathematical equations. However, decisions are emotion-laden rather than cool and analytic when they tap into life-threatening considerations. Using functional magnetic resonance imaging (fMRI), this study investigated the neural mechanisms underlying vital loss decisions. Participants were asked to make a forced choice between two losses across three conditions: both losses are trivial (trivial-trivial), both losses are vital (vital-vital), or one loss is trivial and the other is vital (vital-trivial). Our results revealed that the amygdala was more active and correlated positively with self-reported negative emotion associated with choice during vital-vital loss decisions, when compared to trivial-trivial loss decisions. The rostral anterior cingulate cortex was also more active and correlated positively with self-reported difficulty of choice during vital-vital loss decisions. Compared to the activity observed during trivial-trivial loss decisions, the orbitofrontal cortex and ventral striatum were more active and correlated positively with self-reported positive emotion of choice during vital-trivial loss decisions. Our findings suggest that vital loss decisions involve emotions and cannot be adequately captured by cold computation of minimizing losses. This research will shed light on how people make vital loss decisions

    Clinical trial of focal segmental glomerulosclerosis in children and young adults

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    This NIH-funded multicenter randomized study of focal segmental glomerulosclerosis (FSGS) treatment compared the efficacy of a 12-month course of cyclosporine to a combination of oral pulse dexamethasone and mycophenolate mofetil in children and adults with steroid-resistant primary FSGS. Of the 192 patients enrolled, 138 were randomized to cyclosporine (72) or to mycophenolate/dexamethasone (66). The primary analysis compared the levels of an ordinal variable measuring remission during the first year. The odds ratio (0.59) for achieving at least a partial remission with mycophenolate/dexamethasone compared to cyclosporine was not significant. Partial or complete remission was achieved in 22 mycophenolate/dexamethasone- and 33 cyclosporine-treated patients at 12 months. The main secondary outcome, preservation of remission for 26 weeks following cessation of treatment, was not significantly different between these two therapies. During the entire 78 weeks of study, 8 patients treated with cyclosporine and 7 with mycophenolate/dexamethasone died or developed kidney failure. Thus, our study did not find a difference in rates of proteinuria remission following 12 months of cyclosporine compared to mycophenolate/dexamethasone in patients with steroid-resistant FSGS. However, the small sample size might have prevented detection of a moderate treatment effect

    Density-Independent Mortality and Increasing Plant Diversity Are Associated with Differentiation of Taraxacum officinale into r- and K-Strategists

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    Background: Differential selection between clones of apomictic species may result in ecological differentiation without mutation and recombination, thus offering a simple system to study adaptation and life-history evolution in plants. Methodology/Principal Findings: We caused density-independent mortality by weeding to colonizer populations of the largely apomictic Taraxacum officinale (Asteraceae) over a 5-year period in a grassland biodiversity experiment (Jena Experiment). We compared the offspring of colonizer populations with resident populations deliberately sown into similar communities. Plants raised from cuttings and seeds of colonizer and resident populations were grown under uniform conditions. Offspring from colonizer populations had higher reproductive output, which was in general agreement with predictions of r-selection theory. Offspring from resident populations had higher root and leaf biomass, fewer flower heads and higher individual seed mass as predicted under K-selection. Plants grown from cuttings and seeds differed to some degree in the strength, but not in the direction, of their response to the r- vs. K-selection regime. More diverse communities appeared to exert stronger K-selection on resident populations in plants grown from cuttings, while we did not find significant effects of increasing species richness on plants grown from seeds. Conclusions/Significance: Differentiation into r- and K-strategists suggests that clones with characteristics of r-strategists were selected in regularly weeded plots through rapid colonization, while increasing plant diversity favoured the selection of clones with characteristics of K-strategists in resident populations. Our results show that different selection pressures may result in a rapid genetic differentiation within a largely apomictic species. Even under the assumption that colonizer and resident populations, respectively, happened to be r- vs. K-selected already at the start of the experiment, our results still indicate that the association of these strategies with the corresponding selection regimes was maintained during the 5-year experimental period
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