22,141 research outputs found
Computational Methods and Results for Structured Multiscale Models of Tumor Invasion
We present multiscale models of cancer tumor invasion with components at the
molecular, cellular, and tissue levels. We provide biological justifications
for the model components, present computational results from the model, and
discuss the scientific-computing methodology used to solve the model equations.
The models and methodology presented in this paper form the basis for
developing and treating increasingly complex, mechanistic models of tumor
invasion that will be more predictive and less phenomenological. Because many
of the features of the cancer models, such as taxis, aging and growth, are seen
in other biological systems, the models and methods discussed here also provide
a template for handling a broader range of biological problems
Long- and short-range correlations in the ab-initio no-core shell model
In the framework of the ab-initio no-core shell model (NCSM), we describe the
longitudinal-longitudinal distribution function, part of the inclusive (e,e')
longitudinal response. In the two-body cluster approximation, we compute the
effective operators consistent with the unitary transformation used to obtain
the effective Hamiltonian. When short-range correlations are probed, the
results display independence from the model space size and length scale.
Long-range correlations are more difficult to model in the NCSM and they can be
described only by increasing the model space or increasing the cluster size. In
order to illustrate the model space independence for short-range observables,
we present results for a large set of model spaces for 4He, and in 0-4hw model
spaces for 12C.Comment: 4 pages, 4 figure
Double-stranded RNA elements associated with the MVX disease of Agaricus bisporus
Double-stranded RNA (dsRNA) has been isolated from Agaricus bisporus fruit bodies exhibiting a wide range of disease symptoms. The symptoms which occurred singularly or in combination included; bare cropping areas on commercial beds (primordia disruption), crop delay, premature veil opening, off- or brown-coloured mushrooms, sporophore malformations and loss of crop yield. All symptoms were associated with loss of yield and/or product quality. Collectively, these symptoms are described as mushroom virus X (MVX) disease. The dsRNA titre was much lower than that previously encountered with the La France viral disease of mushrooms and a modified cellulose CF11 protocol was used for their detection. A broad survey of cultivated mushrooms from the British industry identified dsRNA elements ranging between 640 bp and 20.2 kbp; the majority have not previously been described in A. bisporus. 26 dsRNA elements were identified with a maximum of 17, apparently non-encapsidated dsRNA elements, in any one sample. Three dsRNAs (16.2, 9.4 and 2.4 kbp) were routinely found in mushrooms asymptomatic for MVX. Previously, La France disease was effectively contained and controlled by minimising the on-farm production and spread of basidiospores. Our on-farm observations suggest that MVX could be spread by infected spores and/or mycelial fragments
An approximate dynamic programming approach to food security of communities following hazards
Food security can be threatened by extreme natural hazard events for
households of all social classes within a community. To address food security
issues following a natural disaster, the recovery of several elements of the
built environment within a community, including its building portfolio, must be
considered. Building portfolio restoration is one of the most challenging
elements of recovery owing to the complexity and dimensionality of the problem.
This study introduces a stochastic scheduling algorithm for the identification
of optimal building portfolio recovery strategies. The proposed approach
provides a computationally tractable formulation to manage multi-state,
large-scale infrastructure systems. A testbed community modeled after Gilroy,
California, is used to illustrate how the proposed approach can be implemented
efficiently and accurately to find the near-optimal decisions related to
building recovery following a severe earthquake.Comment: As opposed to the preemptive scheduling problem, which was addressed
in multiple works by us, we deal with a non-preemptive stochastic scheduling
problem in this work. Submitted to 13th International Conference on
Applications of Statistics and Probability in Civil Engineering, ICASP13
Seoul, South Korea, May 26-30, 201
Sea Beam Survey of an Active Strike-Slip Fault: The San Clemente Fault in the California Continental Borderland
The San Clemente fault, located in the California Continental Borderland, is an active, northwest trending, right-lateral, wrench fault. Sea Beam data are used to map the major tectonic landforms associated with active submarine faulting in detail unavailable using conventional echo-sounding or seismic reflection data. In the area between North San Clemente Basin and Fortymile Bank, the major late Cenozoic faults are delineated by alignments of numerous tectonic landforms, including scarps, linear trenches, benches, and sags. Character and spatial patterns of these landforms are consistent with dextral wrench faulting, although vertical offsets may be substantial locally. The main trace of the San Clemente fault cuts a straight path directly across the rugged topography of the region, evidence of a steeply dipping fault surface. Basins or sags located at each right step in the en echelon pattern of faults are manifestations of pull-apart basin development in a right-slip fault zone. Seismic reflection profiles show offset reflectors and a graben in late Quaternary turbidites of the Navy Fan, where the fault zone follows a more northerly trend. Modern tectonic activity along the San Clemente fault zone is demonstrated by numerous earthquakes with epicenters located along the fault\u27s trend. The average strike of the San Clemente fault is parallel to the predicted Pacific-North American relative plate motion vector at this location. Therefore we conclude that the San Clemente fault zone is a part of the broad Pacific-North American transform plate boundary and that the southern California region may be considered as a broad shear zone
Inversion improves the recognition of facial expression in thatcherized images
The Thatcher illusion provides a compelling example of the face inversion effect. However, the marked effect of inversion in the Thatcher illusion contrasts to other studies that report only a small effect of inversion on the recognition of facial expressions. To address this discrepancy, we compared the effects of inversion and thatcherization on the recognition of facial expressions. We found that inversion of normal faces caused only a small reduction in the recognition of facial expressions. In contrast, local inversion of facial features in upright thatcherized faces resulted in a much larger reduction in the recognition of facial expressions. Paradoxically, inversion of thatcherized faces caused a relative increase in the recognition of facial expressions. Together, these results suggest that different processes explain the effects of inversion on the recognition of facial expressions and on the perception of the Thatcher illusion. The grotesque perception of thatcherized images is based on a more orientation-sensitive representation of the face. In contrast, the recognition of facial expression is dependent on a more orientation-insensitive representation. A similar pattern of results was evident when only the mouth or eye region was visible. These findings demonstrate that a key component of the Thatcher illusion is to be found in orientation-specific encoding of the features of the face
From non-Hermitian effective operators to large-scale no-core shell model calculations for light nuclei
No-core shell model (NCSM) calculations using ab initio effective
interactions are very successful in reproducing experimental nuclear spectra.
The main theoretical approach is the use of effective operators, which include
correlations left out by the truncation of the model space to a numerically
tractable size. We review recent applications of the effective operator
approach, within a NCSM framework, to the renormalization of the
nucleon-nucleon interaction, as well as scalar and tensor operators.Comment: To be submited to J. Phys. A, special issue on "The Physics of
Non-Hermitian Operators
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