PRex: An Experiment to Investigate Detection of Near-field Particulate Deposition from a Simulated Underground Nuclear Weapons Test Vent
AbstractA radioactive particulate release experiment to produce a near-field ground deposition representative of small-scale venting from an underground nuclear test was conducted to gather data in support of treaty capability development activities. For this experiment, a CO2‐driven “air cannon” was used to inject 140La, a radioisotope of lanthanum with 1.7‐d half-life and strong gamma-ray emissions, into the lowest levels of the atmosphere at ambient temperatures. Witness plates and air samplers were laid out in an irregular grid covering the area where the plume was anticipated to deposit based on climatological wind records. This experiment was performed at the Nevada National Security Site, where existing infrastructure, radiological procedures, and support personnel facilitated planning and execution of the work. A vehicle-mounted NaI(Tl) spectrometer and a polyvinyl toluene-based backpack instrument were used to survey the deposited plume. Hand-held instruments, including NaI(Tl) and lanthanum bromide scintillators and high purity germanium spectrometers, were used to take in situ measurements. Additionally, three soil sampling techniques were investigated and compared. The relative sensitivity and utility of sampling and survey methods are discussed in the context of on-site inspection.
MCNP(TM) Version 5.
The Monte Carlo transport workhorse, MCNP, is undergoing a massive renovation at Los Alamos National Laboratory (LANL) in support of the Eolus Project of the Advanced Simulation and Computing (ASCI) Program. MCNP Version 5 (V5) (expected to be released to RSICC in Spring, 2002) will consist of a major restructuring from FORTRAN-77 (with extensions) to ANSI-standard FORTRAN-90 with support for all of the features available in the present release (MCNP-4C2/4C3). To most users, the look-and-feel of MCNP will not change much except for the improvements (improved graphics, easier installation, better online documentation). For example, even with the major format change, full support for incremental patching will still be provided. In addition to the language and style updates, MCNP V5 will have various new user features. These include improved photon physics, neutral particle radiography, enhancements and additions to variance reduction methods, new source options, and improved parallelism support (PVM, MPI, OpenMP).
The effect of disease on the urinary purine metabolite concentrations in dogs
This prospective study was designed to determine the urinary concentrations of purine metabolites in healthy and diseased dogs. The goals were to test the hypothesis that urine concentrations of terminal purine metabolites will identify dogs with diseases that disturb purine degradation. Five hundred and sixty-three client-owned dogs admitted sequentially to the veterinary medical centre were included. Dogs were divided into groups on the basis of their disease. Urine concentrations of xanthine, uric acid, allantoin and creatinine were measured by high-pressure liquid chromatography. Xanthine and uric acid to creatinine ratios were significantly increased in dogs with chronic kidney disease (p = 0.01). The uric acid to creatinine ratio was significantly increased in dogs with cancer compared with clinically healthy dogs (p = 0.04), and significantly increased in dogs receiving chemotherapy for their disease (p < 0.01). Compared to clinically healthy dogs, xanthine and uric acid to creatinine ratios were significantly increased in dogs with hyperadrenocorticism (p < 0.01, and 0.04, respectively). Therefore, the results of this study found that the urinary concentrations of purine metabolites in dogs are significantly impacted by systemic disease. Cancer, chronic kidney disease, and hyperadrenocorticism are associated with altered concentrations of urinary purine metabolites in dogs.