3,286 research outputs found

    First Light of Engineered Diffusers at the Nordic Optical Telescope Reveal Time Variability in the Optical Eclipse Depth of WASP-12b

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    We present the characterization of two engineered diffusers mounted on the 2.5 meter Nordic Optical Telescope, located at Roque de Los Muchachos, Spain. To assess the reliability and the efficiency of the diffusers, we carried out several test observations of two photometric standard stars, along with observations of one primary transit observation of TrES-3b in the red (R-band), one of CoRoT-1b in the blue (B-band), and three secondary eclipses of WASP-12b in V-band. The achieved photometric precision is in all cases within the sub-millimagnitude level for exposures between 25 and 180 seconds. Along a detailed analysis of the functionality of the diffusers, we add a new transit depth measurement in the blue (B-band) to the already observed transmission spectrum of CoRoT-1b, disfavouring a Rayleigh slope. We also report variability of the eclipse depth of WASP-12b in the V-band. For the WASP-12b secondary eclipses, we observe a secondary-depth deviation of about 5-sigma, and a difference of 6-sigma and 2.5-sigma when compared to the values reported by other authors in similar wavelength range determined from Hubble Space Telescope data. We further speculate about the potential physical processes or causes responsible for this observed variabilityComment: 11 pages, 9 figure

    Overview of the spectrometer optical fiber feed for the Habitable-zone Planet Finder

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    The Habitable-zone Planet Finder (HPF) is a highly stabilized fiber fed precision radial velocity (RV) spectrograph working in the Near Infrared (NIR): 810 - 1280 nm . In this paper we present an overview of the preparation of the optical fibers for HPF. The entire fiber train from the telescope focus down to the cryostat is detailed. We also discuss the fiber polishing, splicing and its integration into the instrument using a fused silica puck. HPF was designed to be able to operate in two modes, High Resolution (HR- the only mode mode currently commissioned) and High Efficiency (HE). We discuss these fiber heads and the procedure we adopted to attach the slit on to the HR fibers.Comment: Presented at 2018 SPIE Astronomical Telescopes + Instrumentation, Austin, Texas, USA. 18 pages, 25 figures, and 2 table

    Identification of a novel neuregulin 1 at-risk haplotype in Han schizophrenia Chinese patients, but no association with the Icelandic/Scottish risk haplotype.

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    To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldTo determine if neuregulin 1 (NRG1) is associated with schizophrenia in Asian populations, we investigated a Han Chinese population using both a family trio design and a case-control design. A total of 25 microsatellite markers and single nucleotide polymorphisms (SNPs) were genotyped spanning the 1.1 Mb NRG1 gene including markers of a seven-marker haplotype at the 5' end of the gene found to be in excess in Icelandic and Scottish schizophrenia patients. The alleles of the individual markers forming the seven marker at-risk haplotype are not likely to be causative as they are not in excess in patients in the Chinese population studied here. However using unrelated patients, we find a novel haplotype (HAP(China 1)), immediately upstream of the Icelandic haplotype, in excess in patients (11.9% in patients vs 4.2% in controls; P=0.0000065, risk ratio (rr) 3.1), which was not significant when parental controls were used. Another haplotype (HAP(China 2)) overlapping the Icelandic risk haplotype was found in excess in the Chinese (8.5% of patients vs 4.0% of unrelated controls; P=0.003, rr 2.2) and was also significant using parental controls only (P=0.0047, rr 2.1). A four-marker haplotype at the 3' end of the NRG1 gene, HAP(China 3), was found at a frequency of 23.8% in patients and 13.7% in nontransmitted parental haplotypes (P=0.000042, rr=2.0) but was not significant in the case-control comparison. We conclude that different haplotypes within the boundaries of the NRG1 gene may be associated with schizophrenia in the Han Chinese

    Immune gene profiles in Atlantic salmon (salmo salar L.) post-smolts infected with SAV3 by bath-challenge show a delayed response and lower levels of gene transcription compared to injected fish

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    Acknowledgements This research was funded by the Research Council of Norway, Research grant # 224885/E40. The following people are thanked for their expert technical assistance and help during sampling; Ann Catherine Bårdsgjære Einen, Stig Mæhle, Ingrid Fiksdal and Miriam Castillo Furné. Thanks also to Ivar Helge Matre at Matre Research Station, IMR for the production of fish and Joachim Nordbø for fish husbandry and help with sampling. Øystein Evensen, Norwegian University of Life Sciences, is acknowledged for providing the SAV3 isolate.Peer reviewedPostprin

    Atlantic salmon adapted to seawater for 9 weeks develop a robust immune response to salmonid alphavirus upon bath challenge

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    This research was funded by the Research Council of Norway. Research grant # 224885/E40. The following people are thanked for their expert technical assistance and help during sampling and analysis; Ann Catherine Einen Bårdsgjære, Stig Mæhle, Ingrid Fiksdal and Miriam Castillo Furné. Thanks also to Ivar Helge Matre (Matre Research Station, Institute for Marine Research) for production of fish and Joachim Nordbø for fish husbandry and help with sampling. Kai Ove Skaftnesmoe is thanked for the preparation of Fig. 6. Øystein Evensen, Norwegian University of Life Sciences, is acknowledged for providing the SAV3 isolate.Peer reviewedPostprin

    Prediction of the effect of dapagliflozin on kidney and heart failure outcomes based on short-term changes in multiple risk markers

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    BACKGROUND: Besides improving glucose control, sodium-glucose co-transporter 2 inhibition with dapagliflozin reduces blood pressure, body weight and urinary albumin:creatinine ratio (UACR) in patients with type 2 diabetes (T2DM). The parameter response efficacy (PRE) score was developed to predict how short-term drug effects on cardiovascular risk markers translate into long-term changes in clinical outcomes. We applied the PRE score to clinical trials of dapagliflozin to model the effect of the drug on kidney and heart failure (HF) outcomes in patients with T2DM and impaired kidney function. METHODS: The relationships between multiple risk markers and long-term outcome were determined in a background population of patients with T2DM with a multivariable Cox model. These relationships were then applied to short-term changes in risk markers observed in a pooled database of dapagliflozin trials (n = 7) that recruited patients with albuminuria to predict the drug-induced changes to kidney and HF outcomes. RESULTS: A total of 132 and 350 patients had UACR >200 mg/g and >30 mg/g at baseline, respectively, and were selected for analysis. The PRE score predicted a risk change for kidney events of -40.8% [95% confidence interval (CI) -51.7 to -29.4) and -40.4% (95% CI -48.4 to -31.1) with dapagliflozin 10 mg compared with placebo for the UACR >200 mg/g and >30 mg/g subgroups. The predicted change in risk for HF events was -27.3% (95% CI -47.7 to -5.1) and -21.2% (95% CI -35.0 to -7.8), respectively. Simulation analyses showed that even with a smaller albuminuria-lowering effect of dapagliflozin (10% instead of the observed 35% in both groups), the estimated kidney risk reduction was still 26.5 and 26.8%, respectively. CONCLUSIONS: The PRE score predicted clinically meaningful reductions in kidney and HF events associated with dapagliflozin therapy in patients with diabetic kidney disease. These results support a large long-term outcome trial in this population to confirm the benefits of the drug on these endpoints

    Correction of anemia by dapagliflozin in patients with type 2 diabetes

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    Aims: Anemia is common in type 2 diabetes (T2D), particularly in patients with kidney impairment, and often goes unrecognized. Dapagliflozin treatment increases hemoglobin and serum erythropoietin levels. We investigated the effect of dapagliflozin 10-mg/day on hemoglobin in T2D patients with and without anemia. Methods: Data from 5325 patients from 14 placebo-controlled, dapagliflozin-treatment studies of at least 24-weeks duration were pooled. Dapagliflozin's effects (vs. placebo) on hemoglobin, serum albumin, estimated glomerular filtration rate (eGFR), systolic blood pressure, body weight, and safety in patients with and without anemia were evaluated. Results: At baseline, 13% of all T2D patients and 28% of those with chronic kidney disease (eGFR Conclusions: Treatment with dapagliflozin can correct and prevent anemia in T2D patients. A gradual increase in hemoglobin beyond week 4 may indicate an erythropoiesis-stimulating effect of sodium-glucose cotransporter 2 inhibition. (c) 2020 Published by Elsevier Inc

    Towards Space-like Photometric Precision from the Ground with Beam-Shaping Diffusers

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    We demonstrate a path to hitherto unachievable differential photometric precisions from the ground, both in the optical and near-infrared (NIR), using custom-fabricated beam-shaping diffusers produced using specialized nanofabrication techniques. Such diffusers mold the focal plane image of a star into a broad and stable top-hat shape, minimizing photometric errors due to non-uniform pixel response, atmospheric seeing effects, imperfect guiding, and telescope-induced variable aberrations seen in defocusing. This PSF reshaping significantly increases the achievable dynamic range of our observations, increasing our observing efficiency and thus better averages over scintillation. Diffusers work in both collimated and converging beams. We present diffuser-assisted optical observations demonstrating 6216+2662^{+26}_{-16}ppm precision in 30 minute bins on a nearby bright star 16-Cygni A (V=5.95) using the ARC 3.5m telescope---within a factor of \sim2 of Kepler's photometric precision on the same star. We also show a transit of WASP-85-Ab (V=11.2) and TRES-3b (V=12.4), where the residuals bin down to 18041+66180^{+66}_{-41}ppm in 30 minute bins for WASP-85-Ab---a factor of \sim4 of the precision achieved by the K2 mission on this target---and to 101ppm for TRES-3b. In the NIR, where diffusers may provide even more significant improvements over the current state of the art, our preliminary tests have demonstrated 13736+64137^{+64}_{-36}ppm precision for a KS=10.8K_S =10.8 star on the 200" Hale Telescope. These photometric precisions match or surpass the expected photometric precisions of TESS for the same magnitude range. This technology is inexpensive, scalable, easily adaptable, and can have an important and immediate impact on the observations of transits and secondary eclipses of exoplanets.Comment: Accepted for publication in ApJ. 30 pages, 20 figure
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