857 research outputs found
Recommended from our members
Well Installation Report for Corrective Action Unit 443, Central Nevada Test Area, Nye County, Nevada, Rev. No.: 0
A Corrective Action Investigation (CAI) was performed in several stages from 1999 to 2003, as set forth in the ''Corrective Action Investigation Plan for the Central Nevada Test Area Subsurface Sites, Corrective Action Unit 443'' (DOE/NV, 1999). Groundwater modeling was the primary activity of the CAI. Three phases of modeling were conducted for the Faultless underground nuclear test. The first phase involved the gathering and interpretation of geologic and hydrogeologic data, and inputting the data into a three-dimensional numerical model to depict groundwater flow. The output from the groundwater flow model was used in a transport model to simulate the migration of a radionuclide release (Pohlmann et al., 2000). The second phase of modeling (known as a Data Decision Analysis [DDA]) occurred after NDEP reviewed the first model. This phase was designed to respond to concerns regarding model uncertainty (Pohll and Mihevc, 2000). The third phase of modeling updated the original flow and transport model to incorporate the uncertainty identified in the DDA, and focused the model domain on the region of interest to the transport predictions. This third phase culminated in the calculation of contaminant boundaries for the site (Pohll et al., 2003). Corrective action alternatives were evaluated and an alternative was submitted in the ''Corrective Action Decision Document/Corrective Action Plan for Corrective Action Unit 443: Central Nevada Test Area-Subsurface'' (NNSA/NSO, 2004). Based on the results of this evaluation, the preferred alternative for CAU 443 is Proof-of-Concept and Monitoring with Institutional Controls. This alternative was judged to meet all requirements for the technical components evaluated and will control inadvertent exposure to contaminated groundwater at CAU 443
Recommended from our members
Subsurface Completion Report for Amchitka Underground Nuclear Test Sites: Long Shot, Milrow, and Cannikin, Rev. No.: 1
Three underground nuclear tests were conducted on Amchitka Island, Alaska, in 1965, 1969, and 1971. The effects of the Long Shot, Milrow, and Cannikin tests on the environment were extensively investigated during and following the detonations, and the area continues to be monitored today. This report is intended to document the basis for the Amchitka Underground Nuclear Test Sites: Long Shot, Milrow, and Cannikin (hereafter referred to as ''Amchitka Site'') subsurface completion recommendation of No Further Remedial Action Planned with Long-Term Surveillance and Maintenance, and define the long-term surveillance and maintenance strategy for the subsurface. A number of factors were considered in evaluating and selecting this recommendation for the Amchitka Site. Historical studies and monitoring data, ongoing monitoring data, the results of groundwater modeling, and the results of an independent stakeholder-guided scientific investigation were also considered in deciding the completion action. Water sampling during and following the testing showed no indication that radionuclides were released to the near surface, or marine environment with the exception of tritium, krypton-85, and iodine-131 found in the immediate vicinity of Long Shot surface ground zero. One year after Long Shot, only tritium was detectable (Merritt and Fuller, 1977). These tritium levels, which were routinely monitored and have continued to decline since the test, are above background levels but well below the current safe drinking water standard. There are currently no feasible means to contain or remove radionuclides in or around the test cavities beneath the sites. Surface remediation was conducted in 2001. Eleven drilling mud pits associated with the Long Shot, Milrow and Cannikin sites were remediated. Ten pits were remediated by stabilizing the contaminants and constructing an impermeable cap over each pit. One pit was remediated by removing all of the contaminated mud for consolidation in another pit. In addition to the mud pits, the hot mix plant was also remediated. Ongoing monitoring data does not indicate that radionuclides are currently seeping into the marine environment. Additionally, the groundwater modeling results indicate no seepage is expected for tens to thousands of years. If seepage does occur in the future, however, the rich, diverse ecosystems around the island could be at risk, as well as people eating foods from the area. An independent science study was conducted by the Consortium for Risk Evaluation with Stakeholder Participation (CRESP) in accordance with the Amchitka Independent Science Plan (2003). The study report was published on August 1, 2005. The CRESP study states ''our geophysical and biological analyses did not find evidence of risk from radionuclides from the consumption of marine foods, nor indication of any current radionuclide contaminated migration into the marine environment from the Amchitka test shots''. The study also found evidence supporting the groundwater modeling conclusions of very slow contaminant transport (CRESP, 2005). While no further action is recommended for the subsurface of the Amchitka Site, long-term stewardship of Amchitka Island will be instituted and will continue into the future. This will include institutional controls management and enforcement, post-completion monitoring, performance of five-year reviews, public participation, and records management. Long-term stewardship will be the responsibility of the U.S. Department of Energy Office of Legacy Management. The Department of Energy is recommending completion of the investigation phase of the Amchitka Sites. The recommended remedy for the Amchitka Site is No Further Action with Long-Term Monitoring and Surveillance. The future long-term stewardship actions will be governed by a Long-Term Surveillance and Maintenance Plan. This Plan is currently being developed with input from the State, landowner, and other interested or affected stakeholders
Wavelet denoising based on local regularity information
International audienceWe present a denoising method that is well fitted to the processing of extremely irregular signals such as (multi)fractal ones. Such signals are often encountered in practice, e.g., in biomedical applications. The basic idea is to estimate the regularity of the original data from the observed noisy ones using the large scale information, and then to extrapolate this information to the small scales. We present theoretical results describing the precise properties of the method. Numerical experiments show that this denoising scheme indeed performs well on irregular signals
Rock glaciers throughout the French Alps accelerated and destabilised since 1990 as air temperatures increased
Rock glaciers—ice-rich creeping landforms typical of permafrost mountain ranges—can develop an anomalous landslide-like behaviour called destabilisation. This behaviour is characterised by failure mechanisms (including cracks and crevasses) and increases in displacement rates by one to two orders of magnitude. Existing studies of this phenomenon have been limited to a small number of landforms and short time spans. Here, we systematically investigate the evolution of rock glacier kinematics over the past seven decades for the entire French Alps by combining observations of landform features indicative of the onset of destabilisation with data on displacements rates using aerial orthoimagery. We show that rock glacier velocities have significantly increased since the 1990s, concurrent with the development of destabilisation in 18 landforms that represent 5% of the 337 active rock glaciers. This pattern of activity correlates with rising air temperatures in the region, which suggests that a warming climate may play a role in this process
Application of fractal tools for the classification of microscopical images of milk fat
International audienceNumerous butter features, such as spreadability, depend on the crystallization, which is observable on microscopical images of milk fat. As microstructures often reveal rough or irregular aspect, fractal tools appear to be particularly adapted to their study. In this paper, fractal techniques quantifying the texture of the image are applied to separate type, plant and day of ripening of different butters. The images are taken from butters produced in industrial conditions. The influence of the crystallization on the fractal parameters has been observed. Fractal quantifiers have demonstrated promising correlations with the day of ripening of the butter. Moreover, they have also shown to be efficient in separating different kinds of butters
Application d'outils fractals pour la classification d'images microscopiques de matières grasses laitières
- De nombreuses caractéristiques du beurre, comme sa "tartinabilité", dépendent de la cristallisation, qui est observable sur les images microscopiques de matière grasse laitière. Comme la microstructure revêt souvent un aspect irrégulier, les outils fractals semblent particulièrement adaptés à l'étude de ces images. Dans ce papier, des techniques fractales reflétant la texture de l'image sont appliquées pour séparer le type, le site de production et le jour de maturation de différents beurres. Les images sont obtenues à partir de beurres produits dans des conditions industrielles. L'influence de la cristallisation a été observée sur ces paramètres fractals. Des corrélations prometteuses avec le jour de maturation ont été démontrées. De plus, il a été possible de séparer différents types de beurre et différents sites de production
Application of fractal tools for the classification of microscopical images of milk fat
International audienceNumerous butter features, such as spreadability, depend on the crystallization, which is observable on microscopical images of milk fat. As microstructures often reveal rough or irregular aspect, fractal tools appear to be particularly adapted to their study. In this paper, fractal techniques quantifying the texture of the image are applied to separate type, plant and day of ripening of different butters. The images are taken from butters produced in industrial conditions. The influence of the crystallization on the fractal parameters has been observed. Fractal quantifiers have demonstrated promising correlations with the day of ripening of the butter. Moreover, they have also shown to be efficient in separating different kinds of butters
Mapping the <i>Shh</i> long-range regulatory domain
Coordinated gene expression controlled by long-distance enhancers is orchestrated by DNA regulatory sequences involving transcription factors and layers of control mechanisms. The Shh gene and well-established regulators are an example of genomic composition in which enhancers reside in a large desert extending into neighbouring genes to control the spatiotemporal pattern of expression. Exploiting the local hopping activity of the Sleeping Beauty transposon, the lacZ reporter gene was dispersed throughout the Shh region to systematically map the genomic features responsible for expression activity. We found that enhancer activities are retained inside a genomic region that corresponds to the topological associated domain (TAD) defined by Hi-C. This domain of approximately 900 kb is in an open conformation over its length and is generally susceptible to all Shh enhancers. Similar to the distal enhancers, an enhancer residing within the Shh second intron activates the reporter gene located at distances of hundreds of kilobases away, suggesting that both proximal and distal enhancers have the capacity to survey the Shh topological domain to recognise potential promoters. The widely expressed Rnf32 gene lying within the Shh domain evades enhancer activities by a process that may be common among other housekeeping genes that reside in large regulatory domains. Finally, the boundaries of the Shh TAD do not represent the absolute expression limits of enhancer activity, as expression activity is lost stepwise at a number of genomic positions at the verges of these domains
csal1 Is Controlled by a Combination of FGF and Wnt Signals in Developing Limb Buds
While some of the signaling molecules that govern establishment of the limb axis have been characterized, little is known about the downstream effector genes that interpret these signals. In Drosophila, the spalt gene is involved in cell fate determination and pattern formation in different tissues. We have cloned a chick homologue of Drosophila spalt, which we have termed csal1, and this study focuses on the regulation of csal1 expression in the limb bud. csal1 is expressed in limb buds from HH 17 to 26, in both the apical ectodermal ridge and the distal mesenchyme. Signals from the apical ridge are essential for csal1 expression, while the dorsal ectoderm is required for csal1 expression at a distance from the ridge. Our data indicate that both FGF and Wnt signals are required for the regulation of csal1 expression in the limb. Mutations in the human homologue of csal1, termed Hsal1/SALL1, result in a condition known as Townes–Brocks syndrome (TBS), which is characterized by preaxial polydactyly. The developmental expression of csal1 together with the digit phenotype in TBS patients suggests that csal1 may play a role in some aspects of distal patterning
- …