Mountaintop Coal Mining and the Clean Water Act: The Fight Over Nationwide Permit 21

The Clean Water Act’s (CWA) goal of protecting the waters of the United States has been threatened by the Army Corps of Engineers (Corps) increased use of general permits, such as Nationwide Permit 21 (NWP 21). NWP 21 is issued by the Corps to authorize the disposal of material from mountaintop coal mining, even though this type of disposal has serious environmental effects. Recent court rulings have upheld the use of NWP 21. However, by focusing on the questions left unresolved by Congress and the courts, there is an opportunity to help guarantee that the goal of the CWA is achieved. To ensure greater environmental protection, the adequacy of the minimum impact determinations performed by the Corps when it enacts a NWP should be challenged to ensure their adequacy, and minimum impact determinations should be required before any issuance of a NWP

GPM-DPR Observations on TGFs Producing Storms

Unique spaceborne measurements of the three-dimensional structure of convective clouds producing terrestrial gamma ray flashes (TGFs) were performed using both active and passive microwave sensors on board the Global Precipitation Measurement (GPM)-Core Observatory satellite, finding coherent features for nine TGF-producing storms. The delineation of cloud structure using the radar reflectivity factor shows convective cells with significant vertical development and thick layers with high ice content. Compared to other cumulonimbus clouds in the tropics, the TGFs counterparts have higher reflectivity values above 3 and 8 km altitude showing in all cases a cumulonimbus tower and the TGFs locations are very close, or coincident, to these high Z columns, where reflectivity exceeds 50dBz. Using the GPM Microwave Imager radiometer, most thunderstorms show a very strong depression of polarization corrected temperature (PCT) at channel 89GHz, indicating a strong scattering signal by ice in the upper cloud layers. At channel 166GHZ, the difference between vertical and horizontal brightness temperature signal always returns positive values, from 0.2 up to 13.7K indicating a complex structure with randomly/vertically oriented ice particles. The PCT was used to characterize the analyzed storms in terms of hydrometeor types, confirming in 7/9 cases a high likelihood of hail/graupel presence. To perform analysis on the TGFs parent flashes, radio atmospherics data from the Earth Networks Total Lightning Network lightning network were used. Waveform data indicate that all cases are intra-cloud events and TGFs typically take place during the peak of flash rate production. Finally, the analysis of the most intense event is shown

The X-Gamma Imaging Spectrometer (XGIS) onboard THESEUS

A compact and modular X and gamma-ray imaging spectrometer (XGIS) has been designed as one of the instruments foreseen on-board the THESEUS mission proposed in response to the ESA M5 call. The experiment envisages the use of CsI scintillator bars read out at both ends by single-cell 25 mm 2 Silicon Drift Detectors. Events absorbed in the Silicon layer (lower energy X rays) and events absorbed in the scintillator crystal (higher energy X rays and Gamma-rays) are discriminated using the on-board electronics. A coded mask provides imaging capabilities at low energies, thus allowing a compact and sensitive instrument in a wide energy band (~2 keV up to ~20 MeV). The instrument design, expected performance and the characterization performed on a series of laboratory prototypes are discussed.Comment: To be published in the Proceedings of the THESEUS Workshop 2017 (http://www.isdc.unige.ch/theseus/workshop2017.html), Journal of the Italian Astronomical Society (Mem.SAIt), Editors L. Amati, E. Bozzo, M. Della Valle, D. Gotz, P. O'Brien. Details on the THESEUS mission concept can be found in the white paper Amati et al. 2017 (arXiv:171004638) and Stratta et al. 2017 (arXiv:1712.08153

GAME: Grb and All-sky Monitor Experiment

We describe the GRB and All-sky Monitor Experiment (GAME) mission submitted by a large international collaboration (Italy, Germany, Czech Repubblic, Slovenia, Brazil) in response to the 2012 ESA call for a small mission opportunity for a launch in 2017 and presently under further investigation for subsequent opportunities. The general scientific objective is to perform measurements of key importance for GRB science and to provide the wide astrophysical community of an advanced X-ray all-sky monitoring system. The proposed payload was based on silicon drift detectors (~1-50 keV), CdZnTe (CZT) detectors (~15-200 keV) and crystal scintillators in phoswich (NaI/CsI) configuration (~20 keV-20 MeV), three well established technologies, for a total weight of ~250 kg and a required power of ~240 W. Such instrumentation allows a unique, unprecedented and very powerful combination of large field of view (3-4 sr), a broad energy energy band extending from ~1 keV up to ~20 MeV, an energy resolution as good as ~300 eV in the 1-30 keV energy range, a source location accuracy of ~1 arcmin. The mission profile included a launch (e.g., by Vega) into a low Earth orbit, a baseline sky scanning mode plus pointed observations of regions of particular interest, data transmission to ground via X-band (4.8 Gb/orbit, Alcantara and Malindi ground stations), and prompt transmission of GRB / transient triggers.Comment: 13 pages, 8 figures, published in International Journal of Modern Physics