760 research outputs found
Prompt Beta Spectroscopy as a Diagnostic for Mix in Ignited NIF Capsules
The National Ignition Facility (NIF) technology is designed to drive
deuterium-tritium (DT) internal confinement fusion (ICF) targets to ignition
using indirect radiation from laser beam energy captured in a hohlraum.
Hydrodynamical instabilities at interfaces in the ICF capsule leading to mix
between the DT fue l and the ablator shell material are of fundamental physical
interest and can affect the performance characteristics of the capsule. In this
Letter we describe new radiochemical diagnostics for mix processes in ICF
capsules with plastic or Be (0.9%Cu) ablator shells. Reactions of high-energy
tritons with shell material produce high-energy -emitters.
We show that mix between the DT fuel and the shell material enhances
high-energy prompt beta emission from these reactions by more than an order of
magnitude over that expected in the absence of mix
Differential Responses of Human and Mouse Lung Epithelial Cells in Inducible Resistance to Viral Infection
https://openworks.mdanderson.org/sumexp21/1240/thumbnail.jp
European wildcat populations are subdivided into five main biogeographic groups: consequences of Pleistocene climate changes or recent anthropogenic fragmentation?
Extant populations of the European wildcat are fragmented across the continent, the likely consequence of recent extirpations due to habitat loss and over-hunting. However, their underlying phylogeographic history has never been reconstructed. For testing the hypothesis that the European wildcat survived the Ice Age fragmented in Mediterranean refuges, we assayed the genetic variation at 31 microsatellites in 668 presumptive European wildcats sampled in 15 European countries. Moreover, to evaluate the extent of subspecies/population divergence and identify eventual wild Ă domestic cat hybrids, we genotyped 26 African wildcats from Sardinia and North Africa and 294 random-bred domestic cats. Results of multivariate analyses and Bayesian clustering confirmed that the European wild and the domestic cats (plus the African wildcats) belong to two well-differentiated clusters (average Đ€ ST = 0.159, r st = 0.392, P > 0.001; Analysis of molecular variance [AMOVA]). We identified from c. 5% to 10% cryptic hybrids in southern and central European populations. In contrast, wild-living cats in Hungary and Scotland showed deep signatures of genetic admixture and introgression with domestic cats. The European wildcats are subdivided into five main genetic clusters (average Đ€ ST = 0.103, r st = 0.143, P > 0.001; AMOVA) corresponding to five biogeographic groups, respectively, distributed in the Iberian Peninsula, central Europe, central Germany, Italian Peninsula and the island of Sicily, and in north-eastern Italy and northern Balkan regions (Dinaric Alps). Approximate Bayesian Computation simulations supported late Pleistocene-early Holocene population splittings (from c. 60 k to 10 k years ago), contemporary to the last Ice Age climatic changes. These results provide evidences for wildcat Mediterranean refuges in southwestern Europe, but the evolution history of eastern wildcat populations remains to be clarified. Historical genetic subdivisions suggest conservation strategies aimed at enhancing gene flow through the restoration of ecological corridors within each biogeographic units. Concomitantly, the risk of hybridization with free-ranging domestic cats along corridor edges should be carefully monitored
Case Report Drug-Induced Thrombocytopenia following a Transvaginal Oocyte Retrieval for In Vitro Fertilization
Drug-induced immune thrombocytopenia has been associated with hundreds of medications and can lead to devastating consequences for the patient. We present a case of a healthy 33-year-old female undergoing in vitro fertilization who developed a severe drug-induced thrombocytopenia, petechiae, and a large hemoperitoneum after receiving Cefazolin antibiotic prophylaxis for a transvaginal oocyte retrieval. The patient was admitted to the intensive care unit for resuscitation with blood products. The presence of drug-dependent platelet antibodies to Cefazolin was confirmed serologically
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Geochemistry of Background Sediment Samples at Technical Area 39, Los Alamos National Laboratory
This report presents results of chemical analyses of 24 analytes in 16 background sediment samples collected from Ancho Canyon and Indio Canyon at Technical Area (TA) 39, Los Alamos National Laboratory. Preliminary upper tolerance limits (UTLS) for sediments are calculated from this data set but, because of the small sample size, these UTLs exceed the maximum values in the data set by up to 50'ZO and will require revision as more background sediment data are obtained
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Migration of Sr-20, Cs-137, and Pu-239/240 in Canyon below Los Alamos outfall
Technical Area-21 (TA-21) of Los Alamos National Laboratory (LANL) is on a mesa bordered by two canyons DP Canyon and Los Alamos (LA) Canyon. DP Canyon is a small semiarid watershed with a well defined channel system where the stream flow is ephemeral. TA-21 has had a complex history of waste disposal as research to determine the chemical and metallurgical properties of nuclear materials occurred here from 1945-1978. Due to these operations, the TA-21 mesa top and bordering canyons have been monitored and characterized by the LANL Environmental Restoration Program. Results identify radionuclide values at outfall. 21-011 (k) which exceed Screening Action Levels, and points along DP Canyon which exceed regional background levels. The radiocontaminants considered in this study are strontium-90, cesium-137, and plutonium-239. This research examines sediment transport and speciation of radionuclide contaminant migration from a source term named SWMU 21-011 (k) down DP Canyon. Three dimensional surface plots of data from 1977-1994 are used to portray the transport and redistribution of radioactive contaminants in an alluvial stream channel. An overall decrease in contamination concentration since 1983 has been observed which could be due to more stringent laboratory controls and also to the removal of main plutonium processing laboratories to another site
Beta decay of 115-In to the first excited level of 115-Sn: Potential outcome for neutrino mass
Recent observation of beta decay of 115-In to the first excited level of
115-Sn with an extremely low Q_beta value (Q_beta ~ 1 keV) could be used to set
a limit on neutrino mass. To give restriction potentially competitive with
those extracted from experiments with 3-H (~2 eV) and 187-Re (~15 eV), atomic
mass difference between 115-In and 115-Sn and energy of the first 115-Sn level
should be remeasured with higher accuracy (possibly of the order of ~1 eV).Comment: 9 pages, 3 figures; talk at the NANP'05 Conferenc
Evolutionary Toxicology: Population-Level Effects of Chronic Contaminant Exposure on the Marsh Frogs (Rana ridibunda) of Azerbaijan
We used molecular methods and population genetic analyses to study the effects of chronic contaminant exposure in marsh frogs from Sumgayit, Azerbaijan. Marsh frogs inhabiting wetlands in Sumgayit are exposed to complex mixtures of chemical contaminants, including petroleum products, pesticides, heavy metals, and many other industrial chemicals. Previous results documented elevated estimates of genetic damage in marsh frogs from the two most heavily contaminated sites. Based on mitochondrial DNA (mtDNA) control region sequence data, the Sumgayit region has reduced levels of genetic diversity, likely due to environmental degradation. The Sumgayit region also acts as an ecological sink, with levels of gene flow into the region exceeding gene flow out of the region. Additionally, localized mtDNA heteroplasmy and diversity patterns suggest that one of the most severely contaminated sites in Sumgayit is acting as a source of new mutations resulting from an increased mutation rate. This study provides an integrated method for assessing the cumulative population impacts of chronic contaminant exposure by studying both population genetic and evolutionary effects
Resection of the liver for colorectal carcinoma metastases - A multi-institutional study of long-term survivors
In this review of a collected series of patients undergoing hepatic resection for colorectal metastases, 100 patients were found to have survived greater than five years from the time of resection. Of these 100 long-term survivors, 71 remain disease-free through the last follow-up, 19 recurred prior to five years, and ten recurred after five years. Patient characteristics that may have contributed to survival were examined. Procedures performed included five trisegmentectomies, 32 lobectomies, 16 left lateral segmentectomies, and 45 wedge resections. The margin of resection was recorded in 27 patients, one of whom had a positive margin, nine of whom had a less than or equal to 1-cm margin, and 17 of whom had a greater than 1-cm margin. Eighty-one patients had a solitary metastasis to the liver, 11 patients had two metastases, one patient had three metastases, and four patients had four metastases. Thirty patients had Stage C primary carcinoma, 40 had Stage B primary carcinoma, and one had Stage A primarycarcinoma. The disease-free interval from the time of colon resection to the time of liver resection was less than one year in 65 patients, and greater than one year in 34 patients. Three patients had bilobar metastases. Four of the patients had extrahepatic disease resected simultaneously with the liver resection. Though several contraindications to hepatic resection have been proposed in the past, five-year survival has been found in patients with extrahepatic disease resected simultaneously, patients with bilobar metastases, patients with multiple metastases, and patients with positive margins. Five-year disease-free survivors are also present in each of these subsets. It is concluded that five-year survival is possible in the presence of reported contraindications to resection, and therefore that the decision to resect the liver must be individualized. © 1988 American Society of Colon and Rectal Surgeons
A nonlinear theory of the parallel firehose and gyrothermal instabilities in a weakly collisional plasma
Weakly collisional plasmas dynamically develop pressure anisotropies with
respect to the magnetic field. These anisotropies trigger plasma instabilities
at scales just above the ion Larmor radius \rho_i and much below the mean free
path \lambda_{mfp}. They have growth rates of a fraction of the ion cyclotron
frequency - much faster than either the global dynamics or local turbulence.
The instabilities dramatically modify the transport properties and, therefore,
the macroscopic dynamics of the plasma. Their nonlinear evolution drives
pressure anisotropies towards marginal stability, controlled by the plasma beta
\beta_i. Here this nonlinear evolution is worked out for the simplest
analytically tractable example - the parallel firehose instability. In the
nonlinear regime, both analytical theory and the numerical solution predict
secular growth of magnetic fluctuations. They develop a k^{-3} spectrum,
extending from scales somewhat larger than \rho_i to the maximum scale that
grows secularly with time (~t^{1/2}); the relative pressure anisotropy
(\pperp-\ppar)/\ppar tends to the marginal value -2/\beta_i. The marginal state
is achieved via changes in the magnetic field, not particle scattering. When a
parallel ion heat flux is present, the firehose mutates into the new
gyrothermal instability (GTI), which continues to exist up to firehose-stable
values of pressure anisotropy, which can be positive and are limited by the
heat flux. The nonlinear evolution of the GTI also features secular growth of
magnetic fluctuations, but the spectrum is eventually dominated by modes around
the scale ~\rho_i l_T/\lambda_{mfp}, where l_T is the scale of the parallel
temperature variation. Implications for momentum and heat transport are
speculated about. This study is motivated by the dynamics of galaxy cluster
plasmas.Comment: 34 pages, replaced with the version published in MNRA
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