다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

The combination of seven-year data from WMAP and improved astrophysical data rigorously tests the standard cosmological model and places new constraints on its basic parameters and extensions. By combining the WMAP data with the latest distance measurements from the baryon acoustic oscillations (BAO) in the distribution of galaxies and the Hubble constant (H0) measurement, we determine the parameters of the simplest six-parameter ΛCDM model. The power-law index of the primordial power spectrum is ns = 0.968 ± 0.012 (68% CL) for this data combination, a measurement that excludes the Harrison–Zel’dovich–Peebles spectrum by 99.5% CL. The other parameters, including those beyond the minimal set, are also consistent with, and improved from, the five-year results. We find no convincing deviations from the minimal model. The seven-year temperature power spectrum gives a better determination of the third acoustic peak, which results in a better determination of the redshift of the matter-radiation equality epoch. Notable examples of improved parameters are the total mass of neutrinos, � mν < 0.58 eV (95% CL), and the effective number of neutrino species, Neff = 4.34 +0.86 −0.88 (68% CL), which benefit from better determinations of the third peak and H0. The limit on a constant dark energy equation of state parameter from WMAP+BAO+H0, without high-redshift Type Ia supernovae, is w =− 1.10 ± 0.14 (68% CL). We detect the effect of primordial helium on the temperature power spectrum and provide a new test of big bang nucleosynthesis by measuring Yp = 0.326 ± 0.075 (68% CL). We detect, and show on the map for the first time, the tangential and radial polarization patterns around hot and cold spots of temperature fluctuations, an important test of physical processes at z = 1090 and the dominance of adiabatic scalar fluctuations. The seven-year polarization data have significantly improved: we now detect the temperature–E-mode polarization cross power spectrum at 21σ , compared with 13σ from the five-year data. With the seven-year temperature–B-mode cross power spectrum, the limit on a rotation of the polarization plane due to potential parity-violating effects has improved by 38% to Δα =− 1. 1 ± 1. 4(statistical) ± 1. 5(systematic) (68% CL). We report significant detections of the Sunyaev–Zel’dovich (SZ) effect at the locations of known clusters of galaxies. The measured SZ signal agrees well with the expected signal from the X-ray data on a cluster-by-cluster basis. However, it is a factor of 0.5–0.7 times the predictions from “universal profile” of Arnaud et al., analytical models, and hydrodynamical simulations. We find, for the first time in the SZ effect, a significant difference between the cooling-flow and non-cooling-flow clusters (or relaxed and non-relaxed clusters), which can explain some of the discrepancy. This lower amplitude is consistent with the lower-than-theoretically expected SZ power spectrum recently measured by the South Pole Telescope Collaboration.

/pdf/seven-year-wilkinson-microwave-anisotropy-probe-wmap-19dgu0rhy7.pdf

Seven-year wilkinson microwave anisotropy probe (wmap *) observations: cosmological interpretation

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 $\sim 1.7\,{\rm{s}}$ 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 $\,{M}_{\odot }$. 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 $\sim 40\,{\rm{Mpc}}$) 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 $\sim 9$ and $\sim 16$ 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 NGC 4993 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.

/pdf/multi-messenger-observations-of-a-binary-neutron-star-merger-3g2lxan5gn.pdf

Multi-messenger observations of a binary neutron star merger

https://boris.unibe.ch/62575/1/1-s2.0-S0277379114003485-main.pdf

A stratigraphic framework for abrupt climatic changes during the Last Glacial period based on three synchronized Greenland ice-core records: refining and extending the INTIMATE event stratigraphy

Over 100 trigonometric parallaxes and proper motions for masers associated with young, high- mass stars have been measured with the Bar and Spiral Structure Legacy Survey, a Very Long Baseline Array key science project, the European VLBI Network, and the Japanese VLBI Exploration of Radio Astrometry project. These measurements provide strong evidence for the existence of spiral arms in the MilkyWay, accurately locating many arm segments and yielding spiral pitch angles ranging from about 7 degrees to 20 degrees. The widths of spiral arms increase with distance from the Galactic center. Fitting axially symmetric models of the MilkyWay with the three- dimensional position and velocity information and conservative priors for the solar and average source peculiar motions, we estimate the distance to the Galactic center, R-0, to be 8.34 +/- 0.16 kpc, a circular rotation speed at the Sun, Theta(0), to be 240 +/- 8 km s(-1), and a rotation curve that is nearly flat ( i. e., a slope of -0.2 +/- 0.4 km s(-1) kpc(-1)) between Galactocentric radii of approximate to 5 and 16 kpc. Assuming a " universal" spiral galaxy form for the rotation curve, we estimate the thin disk scale length to be 2.44 +/- 0.16 kpc. With this large data set, the parameters R-0 and Theta(0) are no longer highly correlated and are relatively insensitive to different forms of the rotation curve. If one adopts a theoretically motivated prior that high- mass star forming regions are in nearly circular Galactic orbits, we estimate a global solar motion component in the direction of Galactic rotation, V-circle dot = 14.6 +/- 5.0 km s(-1). While Theta(0) and V-circle dot are significantly correlated, the sum of these parameters is well constrained, Theta(0) + V circle dot = 255.2 +/- 5.1 km s(-1), as is the angular speed of the Sun in its orbit about the Galactic center, ( Theta(0) + V-circle dot)/R-0 = 30.57 +/- 0.43 km s(-1) kpc(-1). These parameters improve the accuracy of estimates of the accelerations of the Sun and the Hulse-Taylor binary pulsar in their Galactic orbits, significantly reducing the uncertainty in tests of gravitational radiation predicted by general relativity.

https://iopscience.iop.org/article/10.1088/0004-637X/783/2/130/pdf

Trigonometric parallaxes of high mass star forming regions: the structure and kinematics of the milky way

The SKA will deliver orders of magnitude increases in sensitivity, but most astrometric VLBI observations are limited by systematic errors. In these cases improved sensitivity offers no benefit. The best current solution for improving the accuracy of the VLBI calibration is MultiView VLBI, where multiple simultaneous observations around the target are used to deduce the corrections required for the line of sight to the target. 
We have estimated and quantified the applicability of MultiView from real-world ionospheric studies, making projections into achievable astrometric accuracies. These predict systematic measurement errors, with calibrators separated by several degrees, of $\sim$10$\mu$as with current VLBI facilities. For closer calibrators, that are in-beam for single dish VLBI facilities, we predict systematic measurement errors of a few $\mu$as. This is the ideal combination, where the sensitivity of the SKA will provide the precision and MultiView will provide the accuracy. Based on these results we suggest that the SKA design should increase the number of VLBI beams it can form from four to as many as ten.

Investigations on MultiView VLBI for SKA

We present neutral hydrogen (HI) and ionized hydrogen (H${\alpha}$) observations of ten galaxies out to a redshift of 0.1. The HI observations are from the first epoch (178 hours) of the COSMOS HI Large Extragalactic Survey (CHILES). Our sample is HI biased and consists of ten late-type galaxies with HI masses that range from $1.8\times10^{7}$ M$_{\odot}$ to $1.1\times10^{10}$ M$_{\odot}$. We find that although the majority of galaxies show irregularities in the morphology and kinematics, they generally follow the scaling relations found in larger samples. We find that the HI and H${\alpha}$ velocities reach the flat part of the rotation curve. We identify the large-scale structure in the nearby CHILES volume using DisPerSE with the spectroscopic catalog from SDSS. We explore the gaseous properties of the galaxies as a function of location in the cosmic web. We also compare the angular momentum vector (spin) of the galaxies to the orientation of the nearest cosmic web filament. Our results show that galaxy spins tend to be aligned with cosmic web filaments and show a hint of a transition mass associated with the spin angle alignment.

CHILES VI: HI and H${\alpha}$ Observations for z < 0.1 Galaxies; Probing HI Spin Alignment with Filaments in the Cosmic Web.

We are carrying out a simulation study to characterise the advantages of VLBI with multiple beams, which will be a feature of the next generation of instruments. We will focus on VLBI astrometric measurements at lower frequencies (1.4 GHz and below). For our simulations, we have selected a network consisting of ASKAP, the Australian SKA precursor, plus existing Australian antennas from the LBA (Long Baseline Array) and the new antenna in New Zealand (figure 1a). We have used different models to represent the ionospheric turbulences and frequencies. The preliminary results show an improvement of an order of magnitude in the astrometric precision achieved using multiple calibrators with angular separations of a few degrees around the target, with respect to a single nearby (1 away) calibrator. Such astrometric precision is comparable to using in-beam phase referencing with a calibrator some arcminutes away. We plan to expand our simulations to include other networks with multi-beam capability, and ultimately SKA-like configurations.

/pdf/multi-beam-capabilities-for-high-precision-astrometry-at-low-4ba5ak25ta.pdf

Multi-beam capabilities for high precision astrometry at low frequencies using VLBI

We present the development and efforts towards providing global baselines compatible with the innovative Korean VLBI Network receiver system.

Simultaneous multi frequency mm-VLBI on global baselines: The extended KVN

VLBI observations of SiO masers are providing extremely valuable information on the inner circumstellar shells around AGB stars, as well as on the pumping mechanisms responsible for this emission often observed in AGB envelopes. The J=1–0 maser lines (in the v=1 and v=2 vibrationally excited states), at 7 mm wavelength, systematically yield ring-like flux distributions, at about 10 cm from the star (equivalent to a few stellar radii). The structure and dynamics of these inner shells has been studied with a resolution that is equivalent to about 2 10 cm, at the typical distance to these objects. (See e.g. Diamond and Kemball 2003, Desmurs et al. 2000.) The comparison of the brightness distribution for different lines is particularly fruitful. The v=1 and v=2 J=1–0 line distribution is composed of a number of spots that are often shifted by a few mas, and spatial coincidence between both lines is rare (Desmurs et al. 2000, Soria-Ruiz et al. 2004), a result that remains to be theoretically explained. For both lines, the clumps are distributed in ring-like structures, but the v=2 often occupies regions slightly closer to the star. These authors concluded that the relative spatial distribution of v=1,2 spots is an argument in favor of radiative excitation models. SiO v ≥ 1 J=2–1 lines at 3mm wavelength are also strong masers. It is interesting to compare the relative positioning of J=1–0 and J=2–1 lines with theoretical predictions. Both collisional and radiative models clearly predict ‘maser chains’ across the (excited) vibrational ladders, in such a way that the inversion of the different-J transitions in the same v state is mutually reinforced (e.g. Lockett and Elitzur 1992, Bujarrabal 1994). Although the maser phenomenon itself tends in general to amplify differences of any kind, it is difficult to avoid the conclusion that theory does predict that always the v=1 J=1–0 and 2–1 lines must come from the same clumps. However, observations of stars like IRC+10011, RLeo, TXCam and the S-type star χ Cyg, have shown that the v=1 J=1–0 and 2–1 lines are not coincident at all, in fact they occupy quite different regions in the circumstellar shell (Phillips et al. 2003, Soria-Ruiz et al. 2004, Soria-Ruiz et al. 2006, Soria-Ruiz et al. 2007). It is practically impossible

Richard Dodson

Papers

Investigations on MultiView VLBI for SKA

CHILES VI: HI and H${\alpha}$ Observations for z < 0.1 Galaxies; Probing HI Spin Alignment with Filaments in the Cosmic Web.

Multi-beam capabilities for high precision astrometry at low frequencies using VLBI

Simultaneous multi frequency mm-VLBI on global baselines: The extended KVN

Detectability of Circumstellar SiO Maser Emission on VSOP-2 Baselines