12,624 research outputs found
Point-source detection system rejects spatially extended radiation sources
System employing digital space correlation to suppress false target signals in a point-target tracking device is a reliable method for discriminating a distant target from false targets in the field of view of an infrared detection system or tracking device
Morphologic studies of the Moon and planets
The impact, volcanic, and tectonic history of the Moon and planets were investigated over an eight year period. Research on the following topics is discussed: lunar craters, lunar basins, lunar volcanoes, correlation of Apollo geochemical data, lunar geology, Mars desert landforms, and Mars impact basins
The determination of measures of software reliability
Measurement of software reliability was carried out during the development of data base software for a multi-sensor tracking system. The failure ratio and failure rate were found to be consistent measures. Trend lines could be established from these measurements that provide good visualization of the progress on the job as a whole as well as on individual modules. Over one-half of the observed failures were due to factors associated with the individual run submission rather than with the code proper. Possible application of these findings for line management, project managers, functional management, and regulatory agencies is discussed. Steps for simplifying the measurement process and for use of these data in predicting operational software reliability are outlined
Optimum Enterprise Combinations for Representative Farms in Seven Counties of Southwestern Utah, 1967
Resources available for agricultural production were ascertained and trends in their use were studied for seven counties of southwestern Utah. Special consideration was given to cropland, irrigation water, and operating capital as resource restrictions for a linear programming model. Budget data were obtained for crop and livestock enterprises by interviewing farmers and ranchers in the area. Budgets for four representative farm types representing climatic and irrigation differences were made to study crop possibilities. Acreage minimums or maximums for selected crops were established as conservation measures. Budgets were prepared for farm livestock enterprises to use with crop budgets for each representative farm. Results provided profit maximizing enterprise combinations for each representative farm
Comment on "Plasma ionization by annularly bounded helicon waves" [Phys . Plasmas 13, 063501 (2006)]
The neoclassical calculation of the helicon wave theory contains a
fundamental flaw. Use is made of a proportional relationship between the
magnetic field and its curl to derive the Helmholtz equation describing helicon
wave propagation; however, by the fundamental theorem of Stokes, the curl of
the magnetic field must be perpendicular to that portion of the field
contributing to the local curl. Reexamination of the equations of motion
indicates that only electromagnetic waves propagate through a stationary region
of constant pressure in a fully ionized, neutral medium.Comment: 7 pages, 1 figure, to be published in Phys. Plasmas,
http://link.aip.org/link/?PHPAEN/16/054701/
Constraint on the Low Energy Constants of Wilson Chiral Perturbation Theory
Wilson chiral perturbation theory (WChPT) is the effective field theory
describing the long- distance properties of lattice QCD with Wilson or
twisted-mass fermions. We consider here WChPT for the theory with two light
flavors of Wilson fermions or a single light twisted-mass fermion.
Discretization errors introduce three low energy constants (LECs) into
partially quenched WChPT at O(a^2), conventionally called W'_6, W'_7 and W'_8 .
The phase structure of the theory at non-zero a depends on the sign of the
combination 2W'_6 + W'_8, while the spectrum of the lattice Hermitian
Wilson-Dirac operator depends on all three constants. It has been argued, based
on the positivity of partition functions of fixed topological charge, and on
the convergence of graded group integrals that arise in the epsilon-regime of
ChPT, that there is a constraint on the LECs arising from the underlying
lattice theory. In particular, for W'_6 = W'_7 = 0, the constraint found is
W'_8 \le 0. Here we provide an alternative line of argument, based on mass
inequalities for the underlying partially quenched theory. We find that W'_8
\le 0, irrespective of the values of W'_6 and W'_7. Our constraint implies that
2W'_6 > |W'_8| if the phase diagram is to be described by the first-order
scenario, as recent simulations suggest is the case for some choices of action.Comment: 10 pages, no figure
THE ASSOCIATION OF ATRAZINE AND NON-HODGKIN LYMPHOMA IN KENTUCKY
Atrazine, one of the most widely used agricultural pesticides, largely sprayed on corn. throughout the Midwest.34 The Environmental Protection Agency (EPA) has estimated 76.4 million pounds are applied annually where its usage on corn accounts for approximately 86% of total United States (US) domestic usage (in pounds).35 Approximately 75% of the field corn acreage grown in the U.S. is treated with atrazine.35 Once atrazine enters into waterways, it can persist having a half-life greater than 200 days in surface waters.34 In Kentucky, atrazine is the most heavily applied in heavy corn-producing locations, which are mostly in western regions of the state.8 Although some research has suggested a possible link between atrazine exposure and cancers, including breast, thyroid, and ovarian cancers, few studies have focused on the association of atrazine exposure and non-Hodgkin’s lymphoma (NHL). 17,21,38 Even fewer of these studies have assessed atrazine exposure using water sampling data. The purpose of this study was to conduct a descriptive exposure analysis and to evaluate the association between atrazine exposure metrics and NHL in Kentucky. Among the four metrics used to assess atrazine exposure, acres of corn planted, mean concentration level, number of samples above the maximum contaminant level, and percent above the Limit of Detection (LOD), the study found no evidence to support an association between atrazine and NHL. Study findings support the majority of previous research, therefore, strengthening the notion of no association between NHL and atrazine
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