Automated longwall guidance and control vertical control subsystem, volume 2

Software documentation and a computer program listing for a horizon control of a longwall shearer are presented

Vascular Injury After Whole Thoracic X-Ray Irradiation in the Rat

Purpose To study vascular injury after whole thoracic irradiation with single sublethal doses of X-rays in the rat and to develop markers that might predict the severity of injury. Methods and Materials Rats that received 5- or 10-Gy thorax-only irradiation and age-matched controls were studied at 3 days, 2 weeks, and 1, 2, 5, and 12 months. Several pulmonary vascular parameters were evaluated, including hemodynamics, vessel density, total lung angiotensin-converting enzyme activity, and right ventricular hypertrophy. Results By 1 month, the rats in the 10-Gy group had pulmonary vascular dropout, right ventricular hypertrophy, increased pulmonary vascular resistance, increased dry lung weights, and decreases in total lung angiotensin-converting enzyme activity, as well as pulmonary artery distensibility. In contrast, irradiation with 5 Gy resulted in only a modest increase in right ventricular weight and a reduction in lung angiotensin-converting enzyme activity. Conclusion In a previous investigation using the same model, we observed that recovery from radiation-induced attenuation of pulmonary vascular reactivity occurred. In the present study, we report that deterioration results in several vascular parameters for ≤1 year after 10 Gy, suggesting sustained remodeling of the pulmonary vasculature. Our data support clinically relevant injuries that appear in a time- and dose-related manner after exposure to relatively low radiation doses

Aberrational Effects for Shadows of Black Holes

In this paper, we discuss how the shadow of a Kerr black hole depends on the motion of the observer. In particular, we derive an analytical formula for the boundary curve of the shadow for an observer moving with given four-velocity at given Boyer--Lindquist coordinates. We visualize the shadow for various values of parameters.Comment: 12 pages, 3 figures; Proceedings of the 524. WE-Heraeus-Seminar held at the Physikzentrum, Bad Honnef, Germany, 17.--23.2.201

Effelsberg Observations of Excited-State (6.0 GHz) OH in Supernova Remnants and W3(OH)

While masers in the 1720 MHz transition of OH are detected toward many supernova remnants (SNRs), no other OH transition is seen as a maser in SNRs. We present a search for masers at 6049 MHz, which has recently been predicted to produce masers by pure collisional excitation at conditions similar to that required for 1720 MHz masing. The Effelsberg 100 m telescope was used to observe the excited-state 6016, 6030, 6035, and 6049 MHz lines of OH toward selected SNRs, most of which have previously-detected bright 1720 MHz masers. No excited-state masers are found toward SNRs, consistent with previous observations of the 6049 MHz and other excited-state transitions. We do not see clear evidence of absorption toward SNR target positions, although we do see evidence of absorption in the molecular cloud at +50 km/s near Sgr A East. Weak absorption is detected at 6016 MHz toward W3(OH), while stronger, narrower emission is seen at 6049 MHz, suggesting that the 6049 MHz emission is a low-gain maser. We conclude that conditions in SNRs are not conducive to excited-state maser emission, especially in excited-state satellite lines.Comment: 4 pages using emulateapj.cls including 2 tables and 1 figure, accepted to ApJ

Interpretation and the Constraints on International Courts

This paper argues that methodologies of interpretation do not do what they promise – they do not constrain interpretation by providing neutral steps that one can follow in finding out a meaning of a text – but nevertheless do their constraining work by being part of what can be described as the legal practice

The structure of the magnetic field in the massive star-forming region W75N

A debated topic in star formation theory is the role of magnetic fields during the protostellar phase of high-mass stars. It is still unclear how magnetic fields influence the formation and dynamics of massive disks and outflows. Most current information on magnetic fields close to high-mass protostars comes from polarized maser emissions, which allows us to investigate the magnetic field on small scales by using very long-baseline interferometry. The massive star-forming region W75N contains three radio continuum sources (VLA1, VLA2, and VLA3), at three different evolutionary stages, and associated masers, while a large-scale molecular bipolar outflow is also present. Very recently, polarization observations of the 6.7 GHz methanol masers at milliarsecond resolution have been able to probe the strength and structure of the magnetic field over more than 2000 AU around VLA1. The magnetic field is parallel to the outflow, suggesting that VLA1 is its powering source. The observations of water masers at 22 GHz can give more information about the gas dynamics and the magnetic fields around VLA1 and VLA2. The NRAO Very Long Baseline Array was used to measure the linear polarization and the Zeeman-splitting of the 22 GHz water masers in the star-forming region W75N. We detected 124 water masers, 36 around VLA1 and 88 around VLA2 of W75N, which indicate two different physical environments around the two sources, where VLA1 is in a more evolved state. The linear polarization of the masers confirms the tightly ordered magnetic field around VLA1, which is aligned with the large-scale molecular outflow, and also reveals an ordered magnetic field around VLA2, which is not parallel to the outflow. [abridged]Comment: 11 pages, 5 figures, 2 Tables, accepted by Astronomy & Astrophysic

Excited-State OH Masers and Supernova Remnants

The collisionally pumped, ground-state 1720 MHz maser line of OH is widely recognized as a tracer for shocked regions and observed in star-forming regions and supernova remnants. Whereas some lines of excited states of OH have been detected and studied in star-forming regions, the subject of excited-state OH in supernova remnants-where high collision rates are to be expected-is only recently being addressed. Modeling of collisional excitation of OH demonstrates that 1720, 4765, and 6049 MHz masers can occur under similar conditions in regions of shocked gas. In particular, the 6049 and 4765 MHz masers become more significant at increased OH column densities where the 1720 MHz masers begin to be quenched. In supernova remnants, the detection of excited-state OH line maser emission could therefore serve as a probe of regions of higher column densities. Using the Very Large Array, we searched for excited-state OH in the 4.7, 7.8, 8.2, and 23.8 GHz lines in four well-studied supernova remnants with strong 1720 MHz maser emission (Sgr A East, W28, W44 and IC 443). No detections were made, at typical detection limits of around 10 mJy beam-1. The search for the 6 GHz lines were done using Effelsberg since the VLA receivers did not cover those frequencies, and are reported on in an accompanying letter (Fish and coworkers). We also cross-correlated the positions of known supernova remnants with the positions of 1612 MHz maser emission obtained from blind surveys. No probable associations were found, perhaps except in the Sgr A East region. The lack of detections of excited-state OH indicates that the OH column densities suffice for 1720 MHz inversion but not for inversion of excited-state transitions, consistent with the expected results for C-type shocks