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Träfflista för sökning "WFRF:(Visser G. H. A.) srt2:(2010-2014)"

Sökning: WFRF:(Visser G. H. A.) > (2010-2014)

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1.
  • Adrian-Martinez, S., et al. (författare)
  • A first search for coincident gravitational waves and high energy neutrinos using LIGO, Virgo and ANTARES data from 2007
  • 2013
  • Ingår i: Journal of Cosmology and Astroparticle Physics. - : IOP Publishing. - 1475-7516. ; :6
  • Tidskriftsartikel (refereegranskat)abstract
    • We present the results of the first search for gravitational wave bursts associated with high energy neutrinos. Together, these messengers could reveal new, hidden sources that are not observed by conventional photon astronomy, particularly at high energy. Our search uses neutrinos detected by the underwater neutrino telescope ANTARES in its 5 line configuration during the period January - September 2007, which coincided with the fifth and first science runs of LIGO and Virgo, respectively. The LIGO-Virgo data were analysed for candidate gravitational-wave signals coincident in time and direction with the neutrino events. No significant coincident events were observed. We place limits on the density of joint high energy neutrino - gravitational wave emission events in the local universe, and compare them with densities of merger and core-collapse events.
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2.
  • de Graauw, Th., et al. (författare)
  • The Herschel-Heterodyne Instrument for the Far-Infrared (HIFI)
  • 2010
  • Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 518, s. L6-
  • Tidskriftsartikel (refereegranskat)abstract
    • Aims: This paper describes the Heterodyne Instrument for the Far-Infrared (HIFI) that was launched onboard ESA's Herschel Space Observatory in May 2009. Methods: The instrument is a set of 7 heterodyne receivers that are electronically tuneable, covering 480-1250 GHz with SIS mixers and the 1410-1910 GHz range with hot electron bolometer (HEB) mixers. The local oscillator (LO) subsystem comprises a Ka-band synthesizer followed by 14 chains of frequency multipliers and 2 chains for each frequency band. A pair of auto-correlators and a pair of acousto-optical spectrometers process the two IF signals from the dual-polarization, single-pixel front-ends to provide instantaneous frequency coverage of 2 × 4 GHz, with a set of resolutions (125 kHz to 1 MHz) that are better than 0.1 km s-1. Results: After a successful qualification and a pre-launch TB/TV test program, the flight instrument is now in-orbit and completed successfully the commissioning and performance verification phase. The in-orbit performance of the receivers matches the pre-launch sensitivities. We also report on the in-orbit performance of the receivers and some first results of HIFI's operations. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.
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4.
  • Cozen, W., et al. (författare)
  • A meta-analysis of Hodgkin lymphoma reveals 19p13.3 TCF3 as a novel susceptibility locus
  • 2014
  • Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 5, s. 3856-
  • Tidskriftsartikel (refereegranskat)abstract
    • Recent genome-wide association studies (GWAS) of Hodgkin lymphoma (HL) have identified associations with genetic variation at both HLA and non-HLA loci; however, much of heritable HL susceptibility remains unexplained. Here we perform a meta-analysis of three HL GWAS totaling 1,816 cases and 7,877 controls followed by replication in an independent set of 1,281 cases and 3,218 controls to find novel risk loci. We identify a novel variant at 19p13.3 associated with HL (rs1860661; odds ratio (OR) = 0.81, 95% confidence interval (95% CI) = 0.76-0.86, P-combined 3.5 x 10(-10)), located in intron 2 of TCF3 (also known as E2A), a regulator of B-and T-cell lineage commitment known to be involved in HL pathogenesis. This meta-analysis also notes associations between previously published loci at 2p16, 5q31, 6p31, 8q24 and 10p14 and HL subtypes. We conclude that our data suggest a link between the 19p13.3 locus, including TCF3, and HL risk.
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5.
  • Wormser, David, et al. (författare)
  • Adult height and the risk of cause-specific death and vascular morbidity in 1 million people : individual participant meta-analysis
  • 2012
  • Ingår i: International Journal of Epidemiology. - : Oxford University Press (OUP). - 0300-5771 .- 1464-3685. ; 41:5, s. 1419-1433
  • Tidskriftsartikel (refereegranskat)abstract
    • BackgroundThe extent to which adult height, a biomarker of the interplay of genetic endowment and early-life experiences, is related to risk of chronic diseases in adulthood is uncertain.MethodsWe calculated hazard ratios (HRs) for height, assessed in increments of 6.5 cm, using individual-participant data on 174 374 deaths or major non-fatal vascular outcomes recorded among 1 085 949 people in 121 prospective studies.ResultsFor people born between 1900 and 1960, mean adult height increased 0.5-1 cm with each successive decade of birth. After adjustment for age, sex, smoking and year of birth, HRs per 6.5 cm greater height were 0.97 (95% confidence interval: 0.96-0.99) for death from any cause, 0.94 (0.93-0.96) for death from vascular causes, 1.04 (1.03-1.06) for death from cancer and 0.92 (0.90-0.94) for death from other causes. Height was negatively associated with death from coronary disease, stroke subtypes, heart failure, stomach and oral cancers, chronic obstructive pulmonary disease, mental disorders, liver disease and external causes. In contrast, height was positively associated with death from ruptured aortic aneurysm, pulmonary embolism, melanoma and cancers of the pancreas, endocrine and nervous systems, ovary, breast, prostate, colorectum, blood and lung. HRs per 6.5 cm greater height ranged from 1.26 (1.12-1.42) for risk of melanoma death to 0.84 (0.80-0.89) for risk of death from chronic obstructive pulmonary disease. HRs were not appreciably altered after further adjustment for adiposity, blood pressure, lipids, inflammation biomarkers, diabetes mellitus, alcohol consumption or socio-economic indicators.ConclusionAdult height has directionally opposing relationships with risk of death from several different major causes of chronic diseases.
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6.
  • Stolk, Lisette, et al. (författare)
  • Meta-analyses identify 13 loci associated with age at menopause and highlight DNA repair and immune pathways
  • 2012
  • Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 44:3, s. 260-268
  • Tidskriftsartikel (refereegranskat)abstract
    • To newly identify loci for age at natural menopause, we carried out a meta-analysis of 22 genome-wide association studies (GWAS) in 38,968 women of European descent, with replication in up to 14,435 women. In addition to four known loci, we identified 13 loci newly associated with age at natural menopause (at P < 5 × 10(-8)). Candidate genes located at these newly associated loci include genes implicated in DNA repair (EXO1, HELQ, UIMC1, FAM175A, FANCI, TLK1, POLG and PRIM1) and immune function (IL11, NLRP11 and PRRC2A (also known as BAT2)). Gene-set enrichment pathway analyses using the full GWAS data set identified exoDNase, NF-κB signaling and mitochondrial dysfunction as biological processes related to timing of menopause.
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7.
  • van Dishoeck, E. F., et al. (författare)
  • Water in Star-forming Regions with the Herschel Space Observatory (WISH). I. Overview of Key Program and First Results
  • 2011
  • Ingår i: Publications of the Astronomical Society of the Pacific. - : IOP Publishing. - 0004-6280 .- 1538-3873. ; 123:900, s. 138-170
  • Tidskriftsartikel (refereegranskat)abstract
    • Water In Star-forming regions with Herschel (WISH) is a key program on the Herschel Space Observatory designed to probe the physical and chemical structures of young stellar objects using water and related molecules and to follow the water abundance from collapsing clouds to planet-forming disks. About 80 sources are targeted, covering a wide ranee of luminosities-from low ( 10(5) L-circle dot)-and a wide range of evolutionary stages-from cold prestellar cores to warm protostellar envelopes and outflows to disks around young stars. Both the HIFI and PACS instruments are used to observe a variety of lines of H2O, (H2O)-O-18 and chemically related species at the source position and in small maps around the protostars and selected outflow positions. In addition, high-frequency lines of CO, (CO)-C-13, and (CO)-O-18 are obtained with Herschel and are complemented by ground-based observations of dust continuum, HDO, CO and its isotopologs, and other molecules to ensure a self-consistent data set for analysis. An overview of the scientific motivation and observational strategy of the program is given, together with the modeling approach and analysis tools that have been developed. Initial science results are presented. These include a lack of water in cold gas at abundances that are lower than most predictions, strong water emission from shocks in protostellar environments, the importance of UV radiation in heating the gas along outflow walls across the full range of luminosities, and surprisingly widespread detection of the chemically related hydrides OH+ and H2O+ in outflows and foreground gas. Quantitative estimates of the energy budget indicate that H2O is generally not the dominant coolant in the warm dense gas associated with protostars. Very deep limits on the cold gaseous water reservoir in the outer regions of protoplanetary disks are obtained that have profound implications for our understanding of grain growth and mixing in disks.
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8.
  • Caselli, P., et al. (författare)
  • Water vapor toward starless cores : The Herschel view
  • 2010
  • Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 521, s. L29-
  • Tidskriftsartikel (refereegranskat)abstract
    • Aims: Previous studies by the satellites SWAS and Odin provided stringent upper limits on the gas phase water abundance of dark clouds (x(H2O) < 7 × 10-9). We investigate the chemistry of water vapor in starless cores beyond the previous upper limits using the highly improved angular resolution and sensitivity of Herschel and measure the abundance of water vapor during evolutionary stages just preceding star formation. Methods: High spectral resolution observations of the fundamental ortho water (o-H2O) transition (557 GHz) were carried out with the Heterodyne Instrument for the Far Infrared onboard Herschel toward two starless cores: Barnard 68 (hereafter B68), a Bok globule, and LDN 1544 (L1544), a prestellar core embedded in the Taurus molecular cloud complex. Detailed radiative transfer and chemical codes were used to analyze the data. Results: The RMS in the brightness temperature measured for the B68 and L1544 spectra is 2.0 and 2.2 mK, respectively, in a velocity bin of 0.59 km s-1. The continuum level is 3.5 ± 0.2 mK in B68 and 11.4 ± 0.4 mK in L1544. No significant feature is detected in B68 and the 3σ upper limit is consistent with a column density of o-H2O N(o-H2O) < 2.5 × 1013 cm-2, or a fractional abundance x(o-H2O) < 1.3 × 10-9, more than an order of magnitude lower than the SWAS upper limit on this source. The L1544 spectrum shows an absorption feature at a 5σ level from which we obtain the first value of the o-H2O column density ever measured in dark clouds: N(o-H2O) = (8 ± 4) × 1012 cm-2. The corresponding fractional abundance is x(o-H2O) ≃ 5 × 10-9 at radii >7000 AU and ≃2 × 10-10 toward the center. The radiative transfer analysis shows that this is consistent with a x(o-H2O) profile peaking at ≃10-8, 0.1 pc away from the core center, where both freeze-out and photodissociation are negligible. Conclusions: Herschel has provided the first measurement of water vapor in dark regions. Column densities of o-H2O are low, but prestellar cores such as L1544 (with their high central densities, strong continuum, and large envelopes) appear to be very promising tools to finally shed light on the solid/vapor balance of water in molecular clouds and oxygen chemistry in the earliest stages of star formation. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.
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9.
  • Marseille, M. G., et al. (författare)
  • Water abundances in high-mass protostellar envelopes : Herschel observations with HIFI
  • 2010
  • Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 521, s. L32-
  • Tidskriftsartikel (refereegranskat)abstract
    • Aims: We derive the dense core structure and the water abundance in four massive star-forming regions in the hope of understanding the earliest stages of massive star formation. Methods: We present Herschel/HIFI observations of the para-H2O 111-000 and 202-111 and the para-H_218O 111-000 transitions. The envelope contribution to the line profiles is separated from contributions by outflows and foreground clouds. The envelope contribution is modeled with Monte-Carlo radiative transfer codes for dust and molecular lines (MC3D and RATRAN), and the water abundance and the turbulent velocity width as free parameters. Results: While the outflows are mostly seen in emission in high-J lines, envelopes are seen in absorption in ground-state lines, which are almost saturated. The derived water abundances range from 5×10-10 to 4×10-8 in the outer envelopes. We detect cold clouds surrounding the protostar envelope, thanks to the very high quality of the Herschel/HIFI data and the unique ability of water to probe them. Several foreground clouds are also detected along the line of sight. Conclusions: The low H2O abundances in massive dense cores are in accordance with the expectation that high densities and low temperatures lead to freeze-out of water on dust grains. The spread in abundance values is not clearly linked to physical properties of the sources. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation of NASA.Appendix (pages 6 to 7) is only available in electronic form at http://www.aanda.org
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10.
  • Fich, M., et al. (författare)
  • Herschel-PACS spectroscopy of the intermediate mass protostar NGC 7129 FIRS 2
  • 2010
  • Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 518:Article Number: L86
  • Tidskriftsartikel (refereegranskat)abstract
    • Aims. We present preliminary results of the first Herschel spectroscopic observations of NGC 7129 FIRS2, an intermediate mass star-forming region. We attempt to interpret the observations in the framework of an in-falling spherical envelope. Methods. The PACS instrument was used in line spectroscopy mode ( R = 1000-5000) with 15 spectral bands between 63 and 185 mu m. This provided good detections of 26 spectral lines seen in emission, including lines of H2O, CO, OH, O I, and C II. Results. Most of the detected lines, particularly those of H2O and CO, are substantially stronger than predicted by the spherical envelope models, typically by several orders of magnitude. In this paper we focus on what can be learned from the detected CO emission lines. Conclusions. It is unlikely that the much stronger than expected line emission arises in the (spherical) envelope of the YSO. The region hot enough to produce such high excitation lines within such an envelope is too small to produce the amount of emission observed. Virtually all of this high excitation emission must arise in structures such as as along the walls of the outflow cavity with the emission produced by a combination of UV photon heating and/or non-dissociative shocks.
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