381 research outputs found
Some considerations on aggregate sample supports for soil inventory and monitoring
Soil monitoring and inventory require a sampling strategy. One component of this strategy is the support of the basic soil observation: the size and shape of the volume of material that is collected and then analysed to return a single soil datum. Many, but not all, soil sampling schemes use aggregate supports in which material from a set of more than one soil cores, arranged in a given configuration, is aggregated and thoroughly mixed prior to analysis. In this paper, it is shown how the spatial statistics of soil information, collected on an aggregate support, can be computed from the covariance function of the soil variable on a core support (treated as point support). This is done via what is called here the discrete regularization of the core-support function. It is shown how discrete regularization can be used to compute the variance of soil sample means and to quantify the consistency of estimates made by sampling then re-sampling a monitoring network, given uncertainty in the precision with which sample sites are relocated. These methods are illustrated using data on soil organic carbon content from a transect in central England. Two aggregate supports, both based on a 20 m 20 m square, are compared with core support. It is shown that both the precision and the consistency of data collected on an aggregate support are better than data on a core support. This has implications for the design of sampling schemes for soil inventory and monitoring
Argon as a showcase
Electronic-state–lifetime interference is a phenomenon specific for ionization
of atoms and molecules in the hard-x-ray regime. Using resonant KL2,3L2,3
Auger decay in argon as a showcase, we present a model that allows extracting
the interference terms directly from the cross sections of the final
electronic states. The analysis provides fundamental information on the
excitation and decay processes such as probabilities of various decay paths
and the values of the dipole matrix elements for transitions to the excited
states. Our results shed light on the interplay between spectator, shake-down,
and shake-up processes in the relaxation of deep core-hole states
Detailed assignment of normal and resonant Auger spectra of Xe near the L edges
We present a comprehensive experimental and theoretical investigation on the LMM, LMN, and LNN normal Auger spectra of xenon, which reveal excellent agreement with theory when core-hole lifetimes of the two-hole final states are taken into account. Generally, the spectra turned out to be highly complex due to a strong overlap of the Auger transitions subsequent to 2s−11/2, 2p−11/2, and 2p−13/2 ionization. This overlap is due to the splitting of the three initial L core holes and the different final M and N core holes being on the same order of magnitude of several hundred eV. The Auger transitions are assigned in detail based on the theoretical results. Most of the MM, MN, and NN final states are described well based on jj coupling. In addition, we present a detailed assignment of the resonant LM45M45 Auger transition subsequent to the 2s→6p, 7p and 2p→5d, 6d excitations
Lithofacies uncertainty modeling in a siliciclastic reservoir setting by incorporating geological contacts and seismic information
Deterministic modeling lonely provides a unique boundary layout, depending on the geological interpretation or interpolation
from the hard available data. Changing the interpreter’s attitude or interpolation parameters leads to displacing the
location of these borders. In contrary, probabilistic modeling of geological domains such as lithofacies is a critical aspect
to providing information to take proper decision in the case of evaluation of oil reservoirs parameters, that is, applicable
for quantification of uncertainty along the boundaries. These stochastic modeling manifests itself dramatically beyond this
occasion. Conventional approaches of probabilistic modeling (object and pixel-based) mostly suffers from consideration
of contact knowledge on the simulated domains. Plurigaussian simulation algorithm, in contrast, allows reproducing the
complex transitions among the lithofacies domains and has found wide acceptance for modeling petroleum reservoirs.
Stationary assumption for this framework has implications on the homogeneous characterization of the lithofacies. In this
case, the proportion is assumed constant and the covariance function as a typical feature of spatial continuity depends only
on the Euclidean distances between two points. But, whenever there exists a heterogeneity phenomenon in the region, this
assumption does not urge model to generate the desired variability of the underlying proportion of facies over the domain.
Geophysical attributes as a secondary variable in this place, plays an important role for generation of the realistic contact
relationship between the simulated categories. In this paper, a hierarchical plurigaussian simulation approach is used to construct
multiple realizations of lithofacies by incorporating the acoustic impedance as soft data through an oil reservoir in Iran.This research was funded by the National Elites Foundation of Iran in collaboration with research Institute Petroleum of Industry in Iran under the project number of 9265005
Potential Energy Surface Reconstruction and Lifetime Determination of Molecular Double-Core-Hole States in the Hard X-Ray Regime
A combination of resonant inelastic x-ray scattering and resonant Auger
spectroscopy provides complementary information on the dynamic response of
resonantly excited molecules. This is exemplified for CH3I, for which we
reconstruct the potential energy surface of the dissociative I 3d−2 double-
core-hole state and determine its lifetime. The proposed method holds a strong
potential for monitoring the hard x-ray induced electron and nuclear dynamic
response of core-excited molecules containing heavy elements, where ab initio
calculations of potential energy surfaces and lifetimes remain challenging
Stochastic analysis of three-dimensional hydraulic conductivity upscaling in a heterogeneous tropical soil
[EN] Hydraulic conductivity (K) heterogeneity is seldom considered in geotechnical practice for the impossibility of sampling the entire area of interest and for the difficulty of accounting for scale effects. Stochastic three-dimensional K upscaling can tackle these two problems, and a workflow is described with an application in a tropical soil. The application shows that K heterogeneity can be incorporated in the daily practice of the geotechnical modeler while discussing the aspects to consider when performing the upscaling so that the upscaled models reproduce the average fluxes at the fine scale.The authors thank the financial support by the Brazilian National Council for Scientific and Technological Development (CNPq) (Project 401441/2014-8). The doctoral fellowship award to the first author by the Coordination of Improvement of Higher Level Personnel (CAPES) is gratefully acknowledged. The first author thanks the International Mobility Grant awarded by CNPq (200597/2015-9) and Santander mobility. The authors also thank DHI-WASI for providing a FEFLOW Software license.Almeida De-Godoy, V.; Zuquette, L.; Gómez-Hernández, JJ. (2018). Stochastic analysis of three-dimensional hydraulic conductivity upscaling in a heterogeneous tropical soil. Computers and Geotechnics. 100:174-187. https://doi.org/10.1016/j.compgeo.2018.03.004S17418710
A Gibbs sampler for inequality‐constrained geostatistical interpolation and inverse modeling
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94819/1/wrcr11621.pd
Applying Factor Analysis Combined with Kriging and Information Entropy Theory for Mapping and Evaluating the Stability of Groundwater Quality Variation in Taiwan
In Taiwan many factors, whether geological parent materials, human activities, and climate change, can affect the groundwater quality and its stability. This work combines factor analysis and kriging with information entropy theory to interpret the stability of groundwater quality variation in Taiwan between 2005 and 2007. Groundwater quality demonstrated apparent differences between the northern and southern areas of Taiwan when divided by the Wu River. Approximately 52% of the monitoring wells in southern Taiwan suffered from progressing seawater intrusion, causing unstable groundwater quality. Industrial and livestock wastewaters also polluted 59.6% of the monitoring wells, resulting in elevated EC and TOC concentrations in the groundwater. In northern Taiwan, domestic wastewaters polluted city groundwater, resulting in higher NH3-N concentration and groundwater quality instability was apparent among 10.3% of the monitoring wells. The method proposed in this study for analyzing groundwater quality inspects common stability factors, identifies potential areas influenced by common factors, and assists in elevating and reinforcing information in support of an overall groundwater management strategy
Mechanism of KMT5B haploinsufficiency in neurodevelopment in humans and mice
Pathogenic variants in KMT5B, a lysine methyltransferase, are associated with global developmental delay, macrocephaly, autism, and congenital anomalies (OMIM# 617788). Given the relatively recent discovery of this disorder, it has not been fully characterized. Deep phenotyping of the largest (n = 43) patient cohort to date identified that hypotonia and congenital heart defects are prominent features that were previously not associated with this syndrome. Both missense variants and putative loss-of-function variants resulted in slow growth in patient-derived cell lines. KMT5B homozygous knockout mice were smaller in size than their wild-type littermates but did not have significantly smaller brains, suggesting relative macrocephaly, also noted as a prominent clinical feature. RNA sequencing of patient lymphoblasts and Kmt5b haploinsufficient mouse brains identified differentially expressed pathways associated with nervous system development and function including axon guidance signaling. Overall, we identified additional pathogenic variants and clinical features in KMT5B-related neurodevelopmental disorder and provide insights into the molecular mechanisms of the disorder using multiple model systems
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