1,194 research outputs found

    The hot gas content of fossil galaxy clusters

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    We investigate the properties of the hot gas in four fossil galaxy systems detected at high significance in the Planck Sunyaev-Zeldovich (SZ) survey. XMM-Newton observations reveal overall temperatures of kT ~ 5-6 keV and yield hydrostatic masses M500,HE > 3.5 x 10e14 Msun, confirming their nature as bona fide massive clusters. We measure the thermodynamic properties of the hot gas in X-rays (out to beyond R500 in three cases) and derive their individual pressure profiles out to R ~ 2.5 R500 with the SZ data. We combine the X-ray and SZ data to measure hydrostatic mass profiles and to examine the hot gas content and its radial distribution. The average Navarro-Frenk-White (NFW) concentration parameter, c500 = 3.2 +/- 0.4, is the same as that of relaxed `normal' clusters. The gas mass fraction profiles exhibit striking variation in the inner regions, but converge to approximately the cosmic baryon fraction (corrected for depletion) at R500. Beyond R500 the gas mass fraction profiles again diverge, which we interpret as being due to a difference in gas clumping and/or a breakdown of hydrostatic equilibrium in the external regions. Overall our observations point to considerable radial variation in the hot gas content and in the gas clumping and/or hydrostatic equilibrium properties in these fossil clusters, at odds with the interpretation of their being old, evolved and undisturbed. At least some fossil objects appear to be dynamically young.Comment: 4 pages, 2 figures. Accepted for publication in A&

    In Vivo Imaging of Activated Estrogen Receptors in Utero by Estrogens and Bisphenol A

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    Environmental estrogens are of particular concern when exposure occurs during embryonic development. Although there are good models to study estrogenic activity of chemicals in adult animals, developmental exposure is much more difficult to test. The weak estrogenic activity of the environmental estrogen bisphenol A (BPA) in embryos is controversial. We have recently generated transgenic mice that carry a reporter construct with estrogen-responsive elements coupled to luciferase. We show that, using this in vivo model in combination with the IVIS imaging system, activation of estrogen receptors (ERs) by maternally applied BPA and other estrogens can be detected in living embryos in utero. Eight hours after exposure to 1 mg/kg BPA, ER transactivation could be significantly induced in the embryos. This was more potent than would be estimated from in vitro assays, although its intrinsic activity is still lower than that of diethylstilbestrol and 17β-estradiol dipropionate. On the basis of these results, we conclude that the estrogenic potency of BPA estimated using in vitro assays might underestimate its estrogenic potential in embryos

    The dynamics of z~1 clusters of galaxies from the GCLASS survey

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    We constrain the internal dynamics of a stack of 10 clusters from the GCLASS survey at 0.87<z<1.34. We determine the stack cluster mass profile M(r) using the MAMPOSSt algorithm of Mamon et al., the velocity anisotropy profile beta(r) from the inversion of the Jeans equation, and the pseudo-phase-space density profiles Q(r) and Qr(r), obtained from the ratio between the mass density profile and the third power of the (total and, respectively, radial) velocity dispersion profiles of cluster galaxies. Several M(r) models are statistically acceptable for the stack cluster (Burkert, Einasto, Hernquist, NFW). The total mass distribution has a concentration c=r200/r-2=4.0-0.6+1.0, in agreement with theoretical expectations, and is less concentrated than the cluster stellar-mass distribution. The stack cluster beta(r) is similar for passive and star-forming galaxies and indicates isotropic galaxy orbits near the cluster center and increasingly radially elongated with increasing cluster-centric distance. Q(r) and Qr(r) are almost power-law relations with slopes similar to those predicted from numerical simulations of dark matter halos. Combined with results obtained for lower-z clusters we determine the dynamical evolution of galaxy clusters, and compare it with theoretical predictions. We discuss possible physical mechanisms responsible for the differential evolution of total and stellar mass concentrations, and of passive and star-forming galaxy orbits [abridged].Comment: 12 pages, 7 figures. Version accepted for publication in A&A after minor modification

    Shrinking Bouma's window: How to model crowding in dense displays

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    Contains fulltext : 236043.pdf (Publisher’s version ) (Open Access)In crowding, perception of a target deteriorates in the presence of nearby flankers. Traditionally, it is thought that visual crowding obeys Bouma's law, i.e., all elements within a certain distance interfere with the target, and that adding more elements always leads to stronger crowding. Crowding is predominantly studied using sparse displays (a target surrounded by a few flankers). However, many studies have shown that this approach leads to wrong conclusions about human vision. Van der Burg and colleagues proposed a paradigm to measure crowding in dense displays using genetic algorithms. Displays were selected and combined over several generations to maximize human performance. In contrast to Bouma's law, only the target's nearest neighbours affected performance. Here, we tested various models to explain these results. We used the same genetic algorithm, but instead of selecting displays based on human performance we selected displays based on the model’s outputs. We found that all models based on the traditional feedforward pooling framework of vision were unable to reproduce human behaviour. In contrast, all models involving a dedicated grouping stage explained the results successfully. We show how traditional models can be improved by adding a grouping stage.14 p

    Doxorubicin versus doxorubicin and cisplatin in endometrial carcinoma: definitive results of a randomised study (55872) by the EORTC Gynaecological Cancer Group

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    BACKGROUND: Combination chemotherapy yields better response rates which do not always lead to a survival advantage. The aim of this study was to investigate whether the reported differences in the efficacy and toxicity of monotherapy with doxorubicin (DOX) versus combination therapy with cisplatin (CDDP) in endometrial adenocarcinoma lead to significant advantage in favour of the combination. PATIENTS AND METHODS: Eligible patients had histologically-proven advanced and/or recurrent endometrial adenocarcinoma and were chemo-naïve. Treatment consisted of either DOX 60 mg/m(2) alone or CDDP 50 mg/m2 added to DOX 60 mg/m2, every 4 weeks. RESULTS: A total of 177 patients were entered and median follow-up is 7.1 years. The combination DOX-CDDP was more toxic than DOX alone. Haematological toxicity consisted mainly of white blood cell toxicity grade 3 and 4 (55% versus 30%). Non-haematological toxicity consisted mainly of grade 3 and 4 alopecia (72% versus 65%) and nausea/vomiting (36 % versus 12%). The combination DOX-CDDP provided a significantly higher response rate than single agent DOX (P <0.001). Thirty-nine patients (43%) responded on DOX-CDDP [13 complete responses (CRs) and 26 partial responses (PRs)], versus 15 patients (17%) on DOX alone (8 CR and 7 PR). The median overall survival (OS) was 9 months in the DOX-CDDP arm versus 7 months in the DOX alone arm (Wilcoxon P = 0.0654). Regression analysis showed that WHO performance status was statistically significant as a prognostic factor for survival, and stratifying for this factor, treatment effect reaches significance (hazard ratio = 1.46, 95% confidence interval 1.05-2.03, P = 0.024). CONCLUSIONS: In comparison to single agent DOX, the combination of DOX-CDDP results in higher but acceptable toxicity. The response rate produced is significantly higher, and a modest survival benefit is achieved with this combination regimen, especially in patients with a good performance status

    Numerical investigation aerodynamics nacelle-strake effect

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    The focus of this investigation is on the numerical prediction of the nacelle-strake effect on the lift coefficient for transport aircraft in high-lift configurations, i.e. the configurations used in the EUROLIFT II project. Within this project high-Reynolds-number wind-tunnel tests were conducted in the European Transonic Windtunnel (ETW) from 2004 to 2007. The geometry considered, also considered in the present investigation, was a commercial wide-body twin-jet high-lift configuration with flaps and slats in landing configuration. The wind-tunnel model considered is a wing/fuselage configuration with a high bypass ratio through-flow-nacelle with a core body. The complexity of the wind-tunnel model was increased in three successive stages. The final stage III geometry features a nacelle strake on the nacelle inboard surface to optimize the performance of the high-lift configuration. The applied CFD methods include the usage of hexahedral elements in regions of vortical flow, a RSM-g turbulence model and a version of the dissipation model in terms of Scalar and Matrix dissipation with various coefficients. Analysis of the results of the performed computations show that for the present configuration, the nacelle strake effect on maximum lift coefficient can be captured with high accuracy by using steady-flow computations and the CFD practices outlined in this paper

    Evidence for strong evolution in galaxy environmental quenching efficiency between z = 1.6 and z = 0.9

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    Indexación: Web of Science; Scopus.We analyse the evolution of environmental quenching efficiency, the fraction of quenched cluster galaxies which would be star forming if they were in the field, as a function of redshift in 14 spectroscopically confirmed galaxy clusters with 0.87 < z < 1.63 from the Spitzer Adaptation of the Red-Sequence Cluster Survey. The clusters are the richest in the survey at each redshift. Passive fractions rise from 42-13 +10 per cent at z ~ 1.6 to 80-9 +12 per cent at z ~ 1.3 and 88-3 +4 per cent at z < 1.1, outpacing the change in passive fraction in the field. Environmental quenching efficiency rises dramatically from 16-19 +15 per cent at z ~ 1.6 to 62-15 +21 per cent at z~1.3 and 73-7 +8 per cent at z ≲ 1.1. This work is the first to show direct observational evidence for a rapid increase in the strength of environmental quenching in galaxy clusters at z ~ 1.5, where simulations show cluster-mass haloes undergo non-linear collapse and virialization.https://academic.oup.com/mnrasl/article/465/1/L104/241728

    Randomized phase III trial of bleomycin, vindesine, mitomycin-C, and cisplatin (BEMP) versus cisplatin (P) in disseminated squamous-cell carcinoma of the uterine cervix: an EORTC Gynecological Cancer Cooperative Group study

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    PURPOSE: Three previous mitomycin-cisplatin-based chemotherapy trials conducted within the EORTC Gynecological Cancer Cooperative Group (GCCG) in patients with disseminated squamous-cell carcinoma of the uterine cervix (SCCUC) suggested that with such regimens a higher overall response rate and a higher complete response rate could be obtained compared to what might have been expected from cisplatin alone. In that respect the combination of bleomycin, vindesine (Eldesine), mitomycin C and cisplatin (BEMP) was the most promising. In the present study BEMP has been compared with the best single agent, cisplatin (P) in the expectation that improved response rates might translate into a better survival. PATIENTS AND METHODS: Eligible patients were those with SCCUC and disseminated measurable disease outside previously irradiated areas, aged < or = 75 years, with a WHO performance status < or = 2 and adequate bone marrow, renal, hepatic and pulmonary function, who gave consent according to regulations followed in individual institutions. Patients were randomized to BEMP: E 3 mg/m2 day 1, P 50 mg/m2 day 1, B 15 mg (24-hour infusion) day 2-4 and M 8 mg/m2 (at alternate cycles), or P 50 mg/m2. The first four cycles were given every 3 weeks (induction phase). Subsequent cycles were given every four weeks (maintenance phase), during which B was deleted from BEMP (MEP). Patients failing on P could be treated with BEM. Of the 287 patients entered, 235 were eligible and 201 evaluable for response. RESULTS: BEMP induced a significantly higher response rate than P (42% vs. 25%, P = 0.006). There was no difference in complete response rate (11% vs. 7%). BEMP was significantly more toxic than P (+/- BEM), both with respect to hematologic and nonhematologic toxicities. After a median follow-up of 6.1 years, survival curves were not significantly different. Median progression-free survival and overall survival were 5.3 and 10.1 months with BEMP and 4.5 and 9.3 months with P (+/- BEM), respectively. In a multivariate analysis of prognostic factors for survival, a lower age (P = 0.003), a lower performance status (P = 0.0001) and a short (<1 year) interval since diagnosis (P = 0.0152) were all associated with an increased risk of dying. For progression-free survival, lower age, prior radiotherapy, locoregional involvement and no prior surgery were associated with a high risk. Treatment with BEMP or P had no significant impact on survival, but for progression-free survival there was a trend in favor of BEMP (P = 0.0893). Adjusting for prognostic factors did not change the effect of treatment. CONCLUSIONS: Combination chemotherapy with BEMP produces more toxicity and more responses compared with cisplatin alone in patients with disseminated SCCUC, but this does not translate into a better survival. Therefore, in the palliative setting single-agent cisplatin should remain the standard therapy for these patients

    A dose-finding study of miltefosine (hexadecylphosphocholine) in patients with metastatic solid tumours

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    The ether lipid miltefosine (hexadecylphosphocholine) was orally given to patients with various tumours in a dose-finding study. All patients initially received a daily total dose of 100 mg, which in the absence of side-effects was increased to 150 mg and further to 200 mg. A total of 54 patients were entered and were evaluable for gastrointestinal toxicity. Nausea and vomiting were found to be dose-limiting; 22% of patients ultimately tolerated a dose of 100 mg, 59% tolerated a dose of 150 mg and 19% tolerated a dose of 200 mg. In addition 30% of patients developed renal dysfunction, which was thought to be related to the drug. No other toxities were observed. For further phase II studies it is recommended that one starts with a dose of 150 mg daily, divided over three administrations

    Asymptotic Conformal Yano--Killing Tensors for Schwarzschild Metric

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    The asymptotic conformal Yano--Killing tensor proposed in J. Jezierski, On the relation between metric and spin-2 formulation of linearized Einstein theory [GRG, in print (1994)] is analyzed for Schwarzschild metric and tensor equations defining this object are given. The result shows that the Schwarzschild metric (and other metrics which are asymptotically ``Schwarzschildean'' up to O(1/r^2) at spatial infinity) is among the metrics fullfilling stronger asymptotic conditions and supertranslations ambiguities disappear. It is also clear from the result that 14 asymptotic gravitational charges are well defined on the ``Schwarzschildean'' background.Comment: 8 pages, latex, no figure
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