Replication in Genome-Wide Association Studies

Replication helps ensure that a genotype-phenotype association observed in a genome-wide association (GWA) study represents a credible association and is not a chance finding or an artifact due to uncontrolled biases. We discuss prerequisites for exact replication, issues of heterogeneity, advantages and disadvantages of different methods of data synthesis across multiple studies, frequentist vs. Bayesian inferences for replication, and challenges that arise from multi-team collaborations. While consistent replication can greatly improve the credibility of a genotype-phenotype association, it may not eliminate spurious associations due to biases shared by many studies. Conversely, lack of replication in well-powered follow-up studies usually invalidates the initially proposed association, although occasionally it may point to differences in linkage disequilibrium or effect modifiers across studies.Comment: Published in at http://dx.doi.org/10.1214/09-STS290 the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

Improved surface quality of anisotropically etched silicon {111} planes for mm-scale integrated optics

We have studied the surface quality of millimeter-scale optical mirrors produced by etching CZ and FZ silicon wafers in potassium hydroxide to expose the $\{111\}$ planes. We find that the FZ surfaces have four times lower noise power at spatial frequencies up to $500\, {mm}^{-1}$. We conclude that mirrors made using FZ wafers have higher optical quality

Focusing on the extended X-ray emission in 3C 459 with a Chandra follow-up observation

6 pages, 4 figures. Reproduced with permission from Astronomy & Astrophysics. © 2019 ESO.Aims. We investigated the X-ray emission properties of the powerful radio galaxy 3C 459 revealed by a recent Chandra follow-up observation carried out in October 2014 with a 62 ks exposure. Methods. We performed an X-ray spectral analysis from a few selected regions on an image obtained from this observation and also compared the X-ray image with a 4.9 GHz VLA radio map available in the literature. Results. The dominant contribution comes from the radio core but significant X-ray emission is detected at larger angular separations from it, surrounding both radio jets and lobes. According to a scenario in which the extended X-ray emission is due to a plasma collisionally heated by jet-driven shocks and not magnetically dominated, we estimated its temperature to be ∼0.8 keV. This hot gas cocoon could be responsible for the radio depolarization observed in 3C 459, as recently proposed also for 3C 171 and 3C 305. On the other hand, our spectral analysis and the presence of an oxygen K edge, blueshifted at 1.23 keV, cannot exclude the possibility that the X-ray radiation originating from the inner regions of the radio galaxy could be intercepted by some outflow of absorbing material intervening along the line of sight, as already found in some BAL quasars.Peer reviewe

Buoyancy-driven inflow to a relic cold core: the gas belt in radio galaxy 3C 386

We report measurements from an XMM-Newton observation of the low-excitation radio galaxy 3C 386. The study focusses on an X-ray-emitting gas belt, which lies between and orthogonal to the radio lobes of 3C 386 and has a mean temperature of $0.94\pm0.05$ keV, cooler than the extended group atmosphere. The gas in the belt shows temperature structure with material closer to the surrounding medium being hotter than gas closer to the host galaxy. We suggest that this gas belt involves a `buoyancy-driven inflow' of part of the group-gas atmosphere where the buoyant rise of the radio lobes through the ambient medium has directed an inflow towards the relic cold core of the group. Inverse-Compton emission from the radio lobes is detected at a level consistent with a slight suppression of the magnetic field below the equipartition value.Comment: 11 pages, 10 figures, accepted for publication in MNRA

Kelvin-Helmholtz instabilities at the sloshing cold fronts in the Virgo cluster as a measure for the effective ICM viscosity

Sloshing cold fronts (CFs) arise from minor merger triggered gas sloshing. Their detailed structure depends on the properties of the intra-cluster medium (ICM): hydrodynamical simulations predict the CFs to be distorted by Kelvin-Helmholtz instabilities (KHIs), but aligned magnetic fields, viscosity, or thermal conduction can suppress the KHIs. Thus, observing the detailed structure of sloshing CFs can be used to constrain these ICM properties. Both smooth and distorted sloshing CFs have been observed, indicating that the KHI is suppressed in some clusters, but not in all. Consequently, we need to address at least some sloshing clusters individually before drawing general conclusions about the ICM properties. We present the first detailed attempt to constrain the ICM properties in a specific cluster from the structure of its sloshing CF. Proximity and brightness make the Virgo cluster an ideal target. We combine observations and Virgo-specific hydrodynamical sloshing simulations. Here we focus on a Spitzer-like temperature dependent viscosity as a mechanism to suppress the KHI, but discuss the alternative mechanisms in detail. We identify the CF at 90 kpc north and north-east of the Virgo center as the best location in the cluster to observe a possible KHI suppression. For viscosities $\gtrsim$ 10% of the Spitzer value KHIs at this CF are suppressed. We describe in detail the observable signatures at low and high viscosities, i.e. in the presence or absence of KHIs. We find indications for a low ICM viscosity in archival XMM-Newton data and demonstrate the detectability of the predicted features in deep Chandra observations.Comment: Accepted for ApJ; 15 pages, 11 figures. A movie can be found here: http://www.hs.uni-hamburg.de/DE/Ins/Per/Roediger/research.html#Virgo-viscou

Hydrodynamics of a River Undergoing Environmental Restoration: Buffalo River, Buffalo, Ny

Due to its environmental degradation including contaminated sediment, poor water quality, and lost habitat, the lower 9.2 km of the Buffalo River is a Great Lakes Area of Concern (AoC). To better understand the river’s hydrodynamics, particularly the interaction between the downriver and upriver flow, since 2009 five horizontal and five vertical Acoustic Doppler Current Profilers (H-ADCP and V-ADCP, respectively) have been deployed year round in the lower 9km of the Buffalo River. The ADCPs were programmed to take measurements every 15 (H-ADCPs) or 20 minutes (V-ADCPs). Data were processed to ensure integrity and permit temporal changes to be investigated. During the period of ADCP deployment, the Buffalo River has undergone dredging, including a large-scale environmental dredging project which widened and deepened some sections of the river\u27s channel. ADCP measurements document several different flow behaviors including high flow events related to runoff from snowmelt and high precipitation and flow reversals related to the upriver propagation of Lake Erie wind-driven surges. River velocities generally are low (~10cm/s), but may reach up to 2 m/s during high flow events. The Buffalo River also has its own periodic (~1.75 - 2 hr) oscillation (river seiche) that is best observed during times of non-lake surge activity or low downstream velocities. The river seiche persists year round during open as well as ice-covered conditions. Keywords: River, Hydrodynamics, ADCPs, Seiche, Restoration

Stage to Studio

Award for Best Research in the Field of Record Labels or Manufacturers from the Association for Recorded Sound CollectionsWinner of the Kenneth W. Baldridge Prize from the Phi Alpha Theta Honor Society, Hawaii Region Between the late nineteenth and mid-twentieth century, technology transformed the entertainment industry as much as it did such heavy industries as coal and steel. Among those most directly affected were musicians, who had to adapt to successive inventions and refinements in audio technology—from wax cylinders and gramophones to radio and sound films. In this groundbreaking study, James P. Kraft explores the intersection of sound technology, corporate power, and artistic labor during this disruptive period.Kraft begins in the late nineteenth century's "golden age" of musicians, when demand for skilled instrumentalists often exceeded supply, analyzing the conflicts in concert halls, nightclubs, recording studios, radio stations, and Hollywood studios as musicians began to compete not only against their local counterparts but also against highly skilled workers in national "entertainment factories." Kraft offers an illuminating case study in the impact of technology on industry and society—and a provocative chapter in the cultural history of America