168 research outputs found

    New approach for precise computation of Lyman-alpha forest power spectrum with hydrodynamical simulations

    Get PDF
    Current experiments are providing measurements of the flux power spectrum from the Lyman-α forests observed in quasar spectra with unprecedented accuracy. Their interpretation in terms of cosmological constraints requires specific simulations of at least equivalent precision. In this paper, we present a suite of cosmological N-body simulations with cold dark matter and baryons, specifically aiming at modeling the low-density regions of the inter-galactic medium as probed by the Lyman-α forests at high redshift. The simulations were run using the GADGET-3 code and were designed to match the requirements imposed by the quality of the current SDSS-III/BOSS or forthcoming SDSS-IV/eBOSS data. They are made using either 2 × 7683 1 billion or 2 × 1923 14 million particles, spanning volumes ranging from (25 Mpc h−1)3 for high-resolution simulations to (100 Mpc h−1)3 for large-volume ones. Using a splicing technique, the resolution is further enhanced to reach the equivalent of simulations with 2 × 30723 58 billion particles in a (100 Mpc h−1)3 box size, i.e. a mean mass per gas particle of 1.2 × 105M⊙ h−1. We show that the resulting power spectrum is accurate at the 2% level over the full range from a few Mpc to several tens of Mpc. We explore the effect on the one-dimensional transmitted-flux power spectrum of four cosmological parameters (ns, σ8, Ωm and H0) and two astrophysical parameters (T0 and γ) that are related to the heating rate of the intergalactic medium. By varying the input parameters around a central model chosen to be in agreement with the latest Planck results, we built a grid of simulations that allows the study of the impact on the flux power spectrum of these six relevant parameters. We improve upon previous studies by not only measuring the effect of each parameter individually, but also probing the impact of the simultaneous variation of each pair of parameters. We thus provide a full second-order expansion, including cross-terms, around our central model. We check the validity of the second-order expansion with independent simulations obtained either with different cosmological parameters or different seeds. Finally, a comparison to the one-dimensional Lyman-α forest power spectrum obtained with BOSS by [1] shows an excellent agreement

    Evaluation of voriconazole anti-Acanthamoeba polyphaga in vitro activity, rat cornea penetration and efficacy against experimental rat Acanthamoeba keratitis

    Get PDF
    International audienceBackground: Acanthamoeba keratitis (AK) is a sight-threatening infectious disease. Its effective and safe medical therapy remains highly debated. Recently, voriconazole, a monotriazole with noted in vitro activity against a large variety of fungi, has been successfully used both topically and systemically to treat human AK cases.Objectives: To measure anti-Acanthamoeba polyphaga in vitro activity, anti-rat AK efficiency and rat cornea penetration of eye-drop and oral voriconazole.Methods: A. polyphaga was maintained in axenic cultures. In vitro, amoebicidal and cysticidal activities of voriconazole were measured using an XTT assay. AK lesions of Sprague Dawley rats were scored from grade 0 to grade 3. For 21 days, from day 7 post-infection, voriconazole (1% solution) eye drops were instilled or voriconazole was administered by gavage (60 mg/kg/day). After killing, superficial corneal epithelium scrapings were cultured and analysed by PCR, and eye-globe histology was performed. Cornea and plasma concentrations were determined using 2D HPLC separation and tandem MS.Results: In vitro, voriconazole inhibited trophozoite proliferation with an IC50 value of 0.02 mg/L and an IC90 value of 2.86 mg/L; no cysticidal effect was found. In AK rats, eye drops reduced clinical worsening from day 7 to day 14 post-infection and oral voriconazole was not effective. Voriconazole cornea concentrations were directly dependent on the frequency of eye-drop instillations, which resulted in lower plasma concentrations, whilst oral voriconazole resulted in lower cornea concentrations.Conclusions: Present data underline the need for high-frequency eye-drop instillation regimens for efficient AK therapy

    Essential Oil Trunk Injection Into Orchard Trees: Consequences on the Performance and Preference of Hemipteran Pests.

    Full text link
    peer reviewedApples and pears are among the most widely cultivated fruit species in the world. Pesticides are commonly applied using ground sprayers in conventional orchards; however, most of it will not reach the target plant, increasing the contamination of nontarget organisms such as natural predators, pollinators, and decomposers. Trunk injection is an alternative method of pesticide application that could reduce risks to beneficials and workers. Essential oils represent a 'green' alternative to pesticides due to their reported insecticidal, antimicrobial, antiviral, nematicidal, and antifungal properties. The aim of this study was, therefore, to evaluate the impact that the injection of a cinnamon essential oil solution into the trunk of apple and pear trees could have on their respective pests, Dysaphis plantaginea and Cacopsylla pyri, respectively. The feeding behavior (preference), the life history traits (performance), and the timing of this effect were measured. The injection of an essential oil emulsion in trees impacted hemipteran host-plant colonization, as for both species a modification of their preference and of their performance was observed. The feeding behavior of D. plantaginea was altered as a significantly lower proportion of aphids ingested phloem sap on injected trees, suggesting that the aphids starved to death. On the contrary, the feeding behavior of the psyllids was little changed compared to the control condition, implying that the observed mortality was due to intoxication. The results presented here could theoretically be used to control these two orchard hemipteran pests, although the effectiveness in real conditions still has to be demonstrated

    Serum 25-hydroxyvitamin D and 24,25-dihydroxyvitamin D in dogs with sinonasal aspergillosis

    Full text link
    peer reviewedSinonasal aspergillosis (SNA) is a common cause of chronic nasal disease with a still poorly understood pathophysiology and which remains a challenge to treat. There is increasing evidence that vitamin D plays a role in both innate and adaptative immunity. A preliminary retrospective study showed that serum 25-hydroxyvitamin D concentration, measured by high performance liquid chromatography (HPLC), was significantly lower in dogs affected with SNA compared to healthy dogs. Objectives of this prospective study were 1) to compare serum 25(OH)D and 24,25(OH)2D concentrations in dogs with SNA to healthy control dogs and dogs with lymphoplasmacytic rhinitis (LPR) or nasal neoplasia; and 2) to determine if serum 25(OH)D and 24,25(OH)2D concentrations in dogs with SNA change from the time of diagnosis to when a cure is achieved. Twenty dogs with a novel diagnosis of SNA, 12 healthy control dogs, 9 dogs with LPR, 10 dogs with nasal neoplasia were included. Nine dogs with SNA were available for follow up until cure. Serum vitamin D concentrations were measured by liquid chromatography tandem mass spectrometry (LC-MS/MS) and compared: 1) among the different groups using a One-way ANOVA and 2) from diagnosis to cure with a paired t-test (significant p-value <0,05 for both tests). The vitamin D metabolite ratio (VMR) was calculated by dividing the 25(OH)D by the 24,25(OH)2D concentration. Serum 25(OH)D and 24,25(OH)2D were lower in dogs with SNA at the time of diagnosis (mean ± standard deviation = 23.5 ± 7,1 ng/ml – 10,5 ± 4,2 ng/ml, respectively) than in healthy dogs (34,1 ± 7,5 ng/ml; p=0,017 - 18,2 ± 5.4 ng/ml; p = 0,005) while there was no difference between healthy and dogs with tumor (27,8 ± 10,9 ng/ml – 15,4 ± 6,5 ng/ml) or LPR (27,4 ± 13,7 ng/ml – 14,3 ± 8,7 ng/ml). There was no significant difference in serum 25(OH)D and 24,25(OH)2D between dogs with SNA at the time of diagnosis and dogs achieving cure. The VMR was higher in SNA dogs (2,4 ± 0,7) than in control dogs (1,9 ± 0,3; p=0,031 t-test), indicating a decreased catabolic clearance of vitamin D in SNA dogs. These results further support the rationale that vitamin D could play a role in dogs with SNA as it does in human with aspergillosis. Whether hypovitaminosis D could contribute to the development of SNA or if oral supplementation could be a beneficial adjunctive therapy in affected dogs is unknown and warrants future investigations

    Intraoperative carcinoid syndrome during small-bowel neuroendocrine tumour surgery

    Get PDF
    Only few descriptions of intraoperative carcinoid syndrome (ioCS) have been reported. The primary objective of this study was to describe ioCS. A second aim was to identify risk factors of ioCS. We retrospectively analysed patients operated for small-bowel neuroendocrine tumour in our institution between 2007 and 2015, and receiving our preventive local regimen of octreotide continuous administration. ioCS was defined as highly probable in case of rapid (<5 min) arterial blood pressure changes ≥40%, not explained by surgical/anaesthetic management and regressive ≥20% after octreotide bolus injection. Probable cases were ioCS which did not meet all criteria of highly-probable ioCS. Suspected ioCS were detected on the anaesthesia record by an injection of octreotide due to a manifestation which did not meet the criteria for highly-probable or probable ioCS. A total of 81 patients (liver metastases: 59, prior carcinoid syndrome: 49, carcinoid heart disease: 7) were included; 139 ioCS occurred in 45 patients: 45 highly probable, 67 probable and 27 suspected. ioCs was hypertensive (91%) and/or hypotensive (29%). There was no factor, including the use of vasopressors, significantly associated with the occurrence of an ioCS. All surgeries were completed and one patient died from cardiac failure 4 days after surgery. After preoperative octreotide continuous infusion, ioCS were mainly hypertensive. No ioCS risk factors, including vasopressor use, were identified. No intraoperative carcinoid crisis occurred, suggesting the clinical relevance of a standardized octreotide prophylaxis protocol

    Pathogenic variants in THSD4, encoding the ADAMTS-like 6 protein, predispose to inherited thoracic aortic aneurysm

    Get PDF
    Purpose Thoracic aortic aneurysm and dissection (TAAD) is a life-threatening disease with often unrecognized inherited forms. We sought to identify novel pathogenic variants associated with autosomal dominant inheritance of TAAD. Methods We analyzed exome sequencing data from 35 French TAAD families and performed next-generation sequencing capture panel of genes in 1114 unrelated TAAD patients. Functional effects of pathogenic variants identified were validated in cell, tissue, and mouse models. Results We identified five functional variants inTHSD4of which two heterozygous variants lead to a premature termination codon.THSD4encodes ADAMTSL6 (member of the ADAMTS/L superfamily), a microfibril-associated protein that promotes fibrillin-1 matrix assembly. TheTHSD4variants studied lead to haploinsufficiency or impaired assembly of fibrillin-1 microfibrils.Thsd4(+/-)mice showed progressive dilation of the thoracic aorta. Histologic examination of aortic samples from a patient carrying aTHSD4variant and fromThsd4(+/-)mice, revealed typical medial degeneration and diffuse disruption of extracellular matrix. Conclusion These findings highlight the role of ADAMTSL6 in aortic physiology and TAAD pathogenesis. They will improve TAAD management and help develop new targeted therapies

    The Baryon Oscillation Spectroscopic Survey of SDSS-III

    Get PDF
    The Baryon Oscillation Spectroscopic Survey (BOSS) is designed to measure the scale of baryon acoustic oscillations (BAO) in the clustering of matter over a larger volume than the combined efforts of all previous spectroscopic surveys of large scale structure. BOSS uses 1.5 million luminous galaxies as faint as i=19.9 over 10,000 square degrees to measure BAO to redshifts z<0.7. Observations of neutral hydrogen in the Lyman alpha forest in more than 150,000 quasar spectra (g<22) will constrain BAO over the redshift range 2.15<z<3.5. Early results from BOSS include the first detection of the large-scale three-dimensional clustering of the Lyman alpha forest and a strong detection from the Data Release 9 data set of the BAO in the clustering of massive galaxies at an effective redshift z = 0.57. We project that BOSS will yield measurements of the angular diameter distance D_A to an accuracy of 1.0% at redshifts z=0.3 and z=0.57 and measurements of H(z) to 1.8% and 1.7% at the same redshifts. Forecasts for Lyman alpha forest constraints predict a measurement of an overall dilation factor that scales the highly degenerate D_A(z) and H^{-1}(z) parameters to an accuracy of 1.9% at z~2.5 when the survey is complete. Here, we provide an overview of the selection of spectroscopic targets, planning of observations, and analysis of data and data quality of BOSS.Comment: 49 pages, 16 figures, accepted by A

    The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey

    Get PDF
    The Sloan Digital Sky Survey III (SDSS-III) presents the first spectroscopic data from the Baryon Oscillation Spectroscopic Survey (BOSS). This ninth data release (DR9) of the SDSS project includes 535,995 new galaxy spectra (median z=0.52), 102,100 new quasar spectra (median z=2.32), and 90,897 new stellar spectra, along with the data presented in previous data releases. These spectra were obtained with the new BOSS spectrograph and were taken between 2009 December and 2011 July. In addition, the stellar parameters pipeline, which determines radial velocities, surface temperatures, surface gravities, and metallicities of stars, has been updated and refined with improvements in temperature estimates for stars with T_eff<5000 K and in metallicity estimates for stars with [Fe/H]>-0.5. DR9 includes new stellar parameters for all stars presented in DR8, including stars from SDSS-I and II, as well as those observed as part of the SDSS-III Sloan Extension for Galactic Understanding and Exploration-2 (SEGUE-2). The astrometry error introduced in the DR8 imaging catalogs has been corrected in the DR9 data products. The next data release for SDSS-III will be in Summer 2013, which will present the first data from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) along with another year of data from BOSS, followed by the final SDSS-III data release in December 2014.Comment: 9 figures; 2 tables. Submitted to ApJS. DR9 is available at http://www.sdss3.org/dr

    The Baryon Oscillation Spectroscopic Survey of SDSS-III

    Get PDF
    The Baryon Oscillation Spectroscopic Survey (BOSS) is designed to measure the scale of baryon acoustic oscillations (BAO) in the clustering of matter over a larger volume than the combined efforts of all previous spectroscopic surveys of large-scale structure. BOSS uses 1.5 million luminous galaxies as faint as i = 19.9 over 10,000 deg(2) to measure BAO to redshifts z < 0.7. Observations of neutral hydrogen in the Ly alpha forest in more than 150,000 quasar spectra (g < 22) will constrain BAO over the redshift range 2.15 < z < 3.5. Early results from BOSS include the first detection of the large-scale three-dimensional clustering of the Ly alpha forest and a strong detection from the Data Release 9 data set of the BAO in the clustering of massive galaxies at an effective redshift z = 0.57. We project that BOSS will yield measurements of the angular diameter distance d(A) to an accuracy of 1.0% at redshifts z = 0.3 and z = 0.57 and measurements of H(z) to 1.8% and 1.7% at the same redshifts. Forecasts for Ly alpha forest constraints predict a measurement of an overall dilation factor that scales the highly degenerate D-A(z) and H-1(z) parameters to an accuracy of 1.9% at z similar to 2.5 when the survey is complete. Here, we provide an overview of the selection of spectroscopic targets, planning of observations, and analysis of data and data quality of BOSS

    Multi-messenger observations of a binary neutron star merger

    Get PDF
    On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta
    corecore