The extent of the local hi halo

Forty-five high-latitude, OB stars have been observed in the Ly alpha and 21 cm lines of HI in an effort to map out the vertical distribution and extent of the local HI halo. The 25 stars for which a reliable HI colum density can be obtained from Ly alpha lie between 60 and 3100 pc from the plane. The principal result is that the total column density of HI at z 1 kpc is, on the average, 5 + or - 3 x 10 the 19th power/sq cm, or 15% of the total sub HI. At relatively low z the data toward some stars suggest a low effective scale height and fairly high average foreground density, while toward others the effective scale height is large and the average density is low. This can be understood as the result of irregularities in the interstellar medium. A model with half of the HI mass in clouds having radii of a few pc and a Gaussian vertical distribution with sigma sub 2 = 135 pc, and half of the mass in an exponential component with a scale height of 500 pc, gives a satisfactory fit to the data. The technique of comparing Ly alpha and 21 cm column densities is also used to discuss the problem of estimating the distance to several possibly subluminous stars

Global properties of the HI distribution in the outer Milky Way

Aims: We derive the 3-D HI volume density distribution for the Galactic disk out to R = 60 kpc. Methods: Our analysis is based on parameters for the warp and rotation curve derived previously. The data are taken from the Leiden/Argentine/Bonn all sky 21-cm line survey. Results: The Milky Way HI disk is significantly warped but shows a coherent structure out to R = 35 kpc. The radial surface density distribution, the densities in the middle of the warped plane, and the HI scale heights all follow exponential relations. The radial scale length for the surface density distribution of the HI disk is 3.75 kpc. Gas at the outskirts for 40 < R < 60 kpc is described best by a distribution with an exponential radial scale length of 7.5 kpc and a velocity dispersion of 74 km/s. Such a highly turbulent medium fits also well with the average shape of the high velocity profile wings observed at high latitudes. The turbulent pressure gradient of such extra-planar gas is on average in balance with the gravitational forces. About 10% of the Milky Way HI gas is in this state. The large scale HI distribution is lopsided; for R < 15 kpc there is more gas in the south. The HI flaring indicates that this asymmetry is caused by a dark matter wake, located at R = 25 kpc in direction of the Magellanic System. Conclusions: The HI disk is made up of two major components. Most prominent is the normal HI disk which can be traced to R = 35 kpc. This is surrounded by a patchy distribution of highly turbulent gas reaching large scale heights but also large radial distances. At the position of the Sun the exponential scale height in the z direction is 3.9 kpc. This component resembles the anomalous gas discovered previously in some galaxies.Comment: to be published in A&

High-Resolution Images of Diffuse Neutral Clouds in the Milky Way. I. Observations, Imaging, and Basic Cloud Properties

A set of diffuse interstellar clouds in the inner Galaxy within a few hundred pc of the Galactic plane has been observed at an angular resolution of ~1 arcmin combining data from the NRAO Green Bank Telescope and the Very Large Array. At the distance of the clouds the linear resolution ranges from ~1.9 pc to ~2.8 pc. These clouds have been selected to be somewhat out of the Galactic plane and are thus not confused with unrelated emission, but in other respects they are a Galactic population. They are located near the tangent points in the inner Galaxy, and thus at a quantifiable distance: $2.3 \leq R \leq 6.0$ kpc from the Galactic Center, and $-1000 \leq z \leq +610$ pc from the Galactic plane. These are the first images of the diffuse neutral HI clouds that may constitute a considerable fraction of the ISM. Peak HI column densities range from $N_{HI} = 0.8-2.9 \times 10^{20}$ cm$^{-2}$. Cloud diameters vary between about 10 and 100 pc, and their HI mass spans the range from less than a hundred to a few thousands Msun. The clouds show no morphological consistency of any kind except that their shapes are highly irregular. One cloud may lie within the hot wind from the nucleus of the Galaxy, and some clouds show evidence of two distinct thermal phases as would be expected from equilibrium models of the interstellar medium.Comment: 81 pages, 42 figures, accepted for publication in the Astrophysical Journal Supplement Serie

Congressional Discretion in Dealing with the Federal Rules of Evidence

On November 20, 1972, the Supreme Court, pursuant to statutory authority, adopted the Federal Rules of Evidence. The new rules of evidence were not to take effect, however, until ninety days after they had been submitted to Congress. The rules were officially submitted on February 5, 1973, but even before that date they had become the subject of extensive legislative debate. While some attorneys praise the codification of evidence rules as a progressive step, others maintain that certain of these promulgations will have an objectionable impact on the federal judicial system or that the Supreme Court has exceeded its authority to adopt rules of practice and procedure. As a result of this controversy, Congress has enacted a measure which defers the effective date of the rules until approved by an Act of Congress. The objections raised reemphasize a problem that has existed ever since Congress granted to the Supreme Court the power to enact rules of practice and procedure : it is unclear what power Congress possesses to modify rules it considers offensive or beyond the authority of the Supreme Court to adopt. This article focuses on the terms of the applicable rules enabling statutes and examines the various methods by which Congress may respond to the rules

Comment on the paper "Calorimetric Dark Matter Detection with Galactic Center Gas Clouds"

The paper "Calorimetric Dark Matter Detection with Galactic Center Gas Clouds" (Bhoonah et al. 2018) aims to derive limits on dark matter interactions by demanding that heat transfer due to DM interactions is less than that by astrophysical cooling, using clouds in the hot, high-velocity nuclear outflow wind of the Milky Way ($T_{wind} \sim 10^{6-7}$ K, $V_{wind} \sim$ 330 km/s). We argue that clouds in such an extreme environment cannot be assumed to be stable over the long timescales associated with their radiative cooling rates. Furthermore, Bhoonah et al. (2018) uses incorrect parameters for their clouds.Comment: 2 pages, 1 figure. Version appearing in Phys. Rev. Let

GEMINI: A Generic Multi-Modal Natural Interface Framework for Videogames

In recent years videogame companies have recognized the role of player engagement as a major factor in user experience and enjoyment. This encouraged a greater investment in new types of game controllers such as the WiiMote, Rock Band instruments and the Kinect. However, the native software of these controllers was not originally designed to be used in other game applications. This work addresses this issue by building a middleware framework, which maps body poses or voice commands to actions in any game. This not only warrants a more natural and customized user-experience but it also defines an interoperable virtual controller. In this version of the framework, body poses and voice commands are respectively recognized through the Kinect's built-in cameras and microphones. The acquired data is then translated into the native interaction scheme in real time using a lightweight method based on spatial restrictions. The system is also prepared to use Nintendo's Wiimote as an auxiliary and unobtrusive gamepad for physically or verbally impractical commands. System validation was performed by analyzing the performance of certain tasks and examining user reports. Both confirmed this approach as a practical and alluring alternative to the game's native interaction scheme. In sum, this framework provides a game-controlling tool that is totally customizable and very flexible, thus expanding the market of game consumers.Comment: WorldCIST'13 Internacional Conferenc

Improved Current Densities in MgB2 By Liquid-Assisted Sintering

Polycrystalline MgB2 samples with GaN additions were prepared by reaction of Mg, B, and GaN powders. The presence of Ga leads to a low melting eutectic phase which allowed liquid phase sintering and produces plate-like grains. For low-level GaN additions (5% at. % or less), the critical transition temperature, Tc, remained unchanged and in 1T magnetic field, the critical current density, Jc was enhanced by a factor of 2 and 10, for temperatures of \~5K and 20K, respectively. The values obtained are approaching those of hot isostatically pressed samples.Comment: 12 pages, 1 table, 4 figures, accepted in Applied Physics Letter