12,378 research outputs found
Plasma kinetic theory
Plasma kinetic theory is examined. Data cover nonlinear oscillations and plasma turbulence in uniform and nonuniform media
Ground-water resources data of Charlotte, DeSoto, and Hardee Counties, Florida
Charlotte, De Soto, and Hardee counties are east-southeast of
Tampa in west-central peninsular Florida, figure 1. In order to
plan the future water-resource development of the area, information
about the water resources is needed. To meet this need, the Water
Resources Division of the U.S. Geological Survey, in cooperation
with the Peace River Basin Board of the Southwest Florida Water
Management District as part of the statewide cooperative program
with the Division of Geology, Florida Board of Conservation, began
a continuing hydrologic data collection program in July, 1963, as
an initial step in the investigation and evaluation of the groundwater
resources of Hardee and De Soto counties. A similar hydrologic
data program commenced in Charlotte County in July, 1964.
Previous work in Hardee and De Soto counties included a
one year reconnaissance by the Division of Water Resources and
Conservation, Florida Board of Conservation, which concluded in
June, 1963, and resulted in a hydrologic report (Woodard, 1964).
As an outgrowth of the hydrologic data program, a Map Series
report portraying the chemical character of water in the Floridan
aquifer in the southern Peace River basin was prepared in 1967
(Kaufman and Dion).
The data contained herein constitute the basis for the Map
Series report. Additional selected data, including records of wells
and chemical analyses,, on the ground-water resources of the three
county area are also included and are published to make the data
available.
(Document has 28 pages.
Local Solutions for Generic Multidimensional Resonant Wave Conversion
In more than one spatial dimension, resonant linear conversion from one wave
type to another can have a more complex geometry than the familiar 'avoided
crossing' of one-dimensional problems. In previous work we have shown that
helical ray shapes are generic in a mathematical sense. Here we briefly
describe how the local field structure can be computed.Comment: 4 pages, to appear in the AIP Proceedings of the 15th Topical
Conference on RF Power in Plasma
Avoidant symptoms in PTSD predict fear circuit activation during multimodal fear extinction
Convergent evidence suggests that individuals with posttraumatic stress disorder (PTSD)
exhibit exaggerated avoidance behaviors as well as abnormalities in Pavlonian fear
conditioning. However, the link between the two features of this disorder is not well
understood. In order to probe the brain basis of aberrant extinction learning in PTSD, we
administered a multimodal classical fear conditioning/extinction paradigm that incorporated
affectively relevant information from two sensory channels (visual and tactile) while
participants underwent fMRI scanning. The sample consisted of fifteen OEF/OIF veterans
with PTSD. In response to conditioned cues and contextual information, greater avoidance
symptomatology was associated with greater activation in amygdala, hippocampus,
vmPFC, dmPFC, and insula, during both fear acquisition and fear extinction. Heightened
responses to previously conditioned stimuli in individuals with more severe PTSD could
indicate a deficiency in safety learning, consistent with PTSD symptomatology. The close
link between avoidance symptoms and fear circuit activation suggests that this symptom
cluster may be a key component of fear extinction deficits in PTSD and/or may be particularly
amenable to change through extinction-based therapie
The effect of temperature-dependent solubility on the onset of thermosolutal convection in a horizontal porous layer
We consider the onset of thermosolutal (double-diffusive) convection of a binary fluid in a horizontal porous layer subject to fixed temperatures and chemical equilibrium on the bounding surfaces, in the case when the solubility of the dissolved component depends on temperature. We use a linear stability analysis to investigate how the dissolution or precipitation of this component affects the onset of convection and the selection of an unstable wavenumber; we extend this analysis using a Galerkin method to predict the structure of the initial bifurcation and compare our analytical results with numerical integration of the full nonlinear equations. We find that the reactive term may be stabilizing or destabilizing, with subtle effects particularly when the thermal gradient is destabilizing but the solutal gradient is stabilizing. The preferred spatial wavelength of convective cells at onset may also be substantially increased or reduced, and strongly reactive systems tend to prefer direct to subcritical bifurcation. These results have implications for geothermal-reservoir management and ore prospecting
LOFT Monthly Progress Report for September 1980
The fourth nuclear powered small break test (L3-5/5A) was conducted on September 29, 1980. The test was initiated from a steady state operating condition wherein the core was generating heat at a maximum rate of approximately 52 kW/m. The test consisted of two parts: L3-5 simulated a 4-in. pipe break in a commerical pressurized water reactor; the second part, L3-5A, was intended to investigate natural circulation and steam generator heat transfer modes and also plan recovery using secondary system control in a situation where the pipe break and the ECCS accumulator are isolated from the primary coolant system. Initial test data indicated that all systems functioned as expected. The several hundred measurements of system coolant and reactor core conditions made during the three hour duration of the test will continue to be analyzed over the next several months. Preparations were also underway for conduting three tests in the Anticipated Transient Series. These tests, designated L6-1, L6-2, and L6-3 will provide information on plant control systems and operator response to transients in which the initiating event is not a loss-of-primary coolant. The transient tests to be conducted during September and others scheduled in the future will add greatly to understanding responses necessary to a transient condition. September 1980 marked the successful completion of FY-1980. Final closing values for each of the funding sources are included as part of this report. NRC and foreign funded tasks closed FY-1980 with underruns documented by identifying committed and uncommitted carryovers
Potts-Percolation-Gauss Model of a Solid
We study a statistical mechanics model of a solid. Neighboring atoms are
connected by Hookian springs. If the energy is larger than a threshold the
"spring" is more likely to fail, while if the energy is lower than the
threshold the spring is more likely to be alive. The phase diagram and
thermodynamic quantities, such as free energy, numbers of bonds and clusters,
and their fluctuations, are determined using renormalization-group and
Monte-Carlo techniques.Comment: 10 pages, 12 figure
Testing Linear-Invariant Non-Linear Properties
We consider the task of testing properties of Boolean functions that are
invariant under linear transformations of the Boolean cube. Previous work in
property testing, including the linearity test and the test for Reed-Muller
codes, has mostly focused on such tasks for linear properties. The one
exception is a test due to Green for "triangle freeness": a function
f:\cube^{n}\to\cube satisfies this property if do not all
equal 1, for any pair x,y\in\cube^{n}.
Here we extend this test to a more systematic study of testing for
linear-invariant non-linear properties. We consider properties that are
described by a single forbidden pattern (and its linear transformations), i.e.,
a property is given by points v_{1},...,v_{k}\in\cube^{k} and
f:\cube^{n}\to\cube satisfies the property that if for all linear maps
L:\cube^{k}\to\cube^{n} it is the case that do
not all equal 1. We show that this property is testable if the underlying
matroid specified by is a graphic matroid. This extends
Green's result to an infinite class of new properties.
Our techniques extend those of Green and in particular we establish a link
between the notion of "1-complexity linear systems" of Green and Tao, and
graphic matroids, to derive the results.Comment: This is the full version; conference version appeared in the
proceedings of STACS 200
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