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Higher Fertilizer Inputs Increase Fitness Traits of Brown Planthopper in Rice.
Rice (Oryza sativa L.) is the primary staple food source for more than half of the world's population. In many developing countries, increased use of fertilizers is a response to increase demand for rice. In this study, we investigated the effects of three principal fertilizer components (nitrogen, phosphorus and potassium) on the development of potted rice plants and their effects on fitness traits of the brown planthopper (BPH) [Nilaparvata lugens (Stål) (Homoptera: Delphacidae)], which is a major pest of rice in Bangladesh and elsewhere. Compared to low fertilizer inputs, high fertilizer treatments induced plant growth but also favored BPH development. The BPH had higher survival, developed faster, and the intrinsic rate of natural increase (r m ) was higher on well-fertilized than under-fertilized plants. Among the fertilizer inputs, nitrogen had the strongest effect on the fitness traits of BPH. Furthermore, both the "Plant vigor hypothesis" and the "Plant stress hypothesis" were supported by the results, the former hypothesis more so than the latter. These hypotheses suggest that the most suitable/attractive hosts for insect herbivores are the most vigorous plants. Our findings emphasized that an exclusive focus on yield increases through only enhanced crop fertilization may have unforeseen, indirect, effects on crop susceptibility to pests, such as BPH
Scalar radius of the pion in the Kroll-Lee-Zumino renormalizable theory
The Kroll-Lee-Zumino renormalizable Abelian quantum field theory of pions and
a massive rho-meson is used to calculate the scalar radius of the pion at next
to leading (one loop) order in perturbation theory. Due to renormalizability,
this determination involves no free parameters. The result is . This value gives for , the low energy constant of
chiral perturbation theory, , and , where F
is the pion decay constant in the chiral limit. Given the level of accuracy in
the masses and the coupling, the only sizable uncertainty in this
result is due to the (uncalculated) NNLO contribution
Mobile Computing in Physics Analysis - An Indicator for eScience
This paper presents the design and implementation of a Grid-enabled physics
analysis environment for handheld and other resource-limited computing devices
as one example of the use of mobile devices in eScience. Handheld devices offer
great potential because they provide ubiquitous access to data and
round-the-clock connectivity over wireless links. Our solution aims to provide
users of handheld devices the capability to launch heavy computational tasks on
computational and data Grids, monitor the jobs status during execution, and
retrieve results after job completion. Users carry their jobs on their handheld
devices in the form of executables (and associated libraries). Users can
transparently view the status of their jobs and get back their outputs without
having to know where they are being executed. In this way, our system is able
to act as a high-throughput computing environment where devices ranging from
powerful desktop machines to small handhelds can employ the power of the Grid.
The results shown in this paper are readily applicable to the wider eScience
community.Comment: 8 pages, 7 figures. Presented at the 3rd Int Conf on Mobile Computing
& Ubiquitous Networking (ICMU06. London October 200
Pion form factor in the Kroll-Lee-Zumino model
The renormalizable Abelian quantum field theory model of Kroll, Lee, and
Zumino is used to compute the one-loop vertex corrections to the tree-level,
Vector Meson Dominance (VMD) pion form factor. These corrections, together with
the known one-loop vacuum polarization contribution, lead to a substantial
improvement over VMD. The resulting pion form factor in the space-like region
is in excellent agreement with data in the whole range of accessible momentum
transfers. The time-like form factor, known to reproduce the Gounaris-Sakurai
formula at and near the rho-meson peak, is unaffected by the vertex correction
at order (g_\rpp^2).Comment: Revised version corrects a misprint in Eq.(1
Intrinsic and extrinsic x-ray absorption effects in soft x-ray diffraction from the superstructure in magnetite
We studied the (001/2) diffraction peak in the low-temperature phase of
magnetite (Fe3O4) using resonant soft x-ray diffraction (RSXD) at the Fe-L2,3
and O-K resonance. We studied both molecular-beam-epitaxy (MBE) grown thin
films and in-situ cleaved single crystals. From the comparison we have been
able to determine quantitatively the contribution of intrinsic absorption
effects, thereby arriving at a consistent result for the (001/2) diffraction
peak spectrum. Our data also allow for the identification of extrinsic effects,
e.g. for a detailed modeling of the spectra in case a "dead" surface layer is
present that is only absorbing photons but does not contribute to the
scattering signal.Comment: to appear in Phys. Rev.
Cryogenic silicon detectors with implanted contacts for the detection of visible photons using the Neganov-Luke Effect
There is a common need in astroparticle experiments such as direct dark
matter detection, 0{\nu}\b{eta}\b{eta} (double beta decay without emission of
neutrinos) and Coherent Neutrino Nucleus Scattering experiments for light
detectors with a very low energy threshold. By employing the Neganov-Luke
Effect, the thermal signal of particle interactions in a semiconductor absorber
operated at cryogenic temperatures, can be amplified by drifting the
photogenerated electrons and holes in an electric field. This technology is not
used in current experiments, in particular because of a reduction of the signal
amplitude with time which is due to trapping of the charges within the
absorber. We present here the first results of a novel type of Neganov-Luke
Effect detector with an electric field configuration designed to improve the
charge collection within the semiconductor.Comment: 6 pages, 5 figures, submitted to Journal of Low Temperature Physic
INFORMATION TECHNOLOGIES AND THE DESIGN AND ANALYSIS OF SITE-SPECIFIC EXPERIMENTS WITHIN COMMERCIAL COTTON FIELDS
Information products derived from multi-spectral remote sensing images, LIDAR elevations, or data products from other sensor systems (soil electrical conductivity measurements, yield monitors, etc.) characterize potential crop productivity by mapping biophysical aspects of cropland variability. These sensor systems provide spectral, spatial, and temporal measurements at resolutions and accuracies describing the variability of in-field, physical characteristic phenomena, including management practices from cropland preparation, selection of crop cultivars, and variable-rate applications of inputs. In addition, DGPS-equipped (differential, global positioning system) harvesters monitor yield response at closely spaced, georeferenced points. Geographic information system and image processing techniques fuse diverse information sources to spatially characterize cropland, describe management practices, and quantify the variable yield response. Following fusion of information sources, effectiveness of spatially applied management practices may be evaluated by designed experiments assessing impacts on yield caused by geo-referenced relationships between (1) uncontrollable spatial components (the environment) and (2) controllable management practices (cultivar selection, fertility management, herbicide, insecticide, and plant growth regulator applications, etc.). These kinds of experiments can be designed because farming equipment can be computer controlled through DGPS giving farmers the ability to continuously change applied treatments for many farming operations. A mixed linear model involving both uncontrollable and controllable management attributes attached as spatial descriptors to yield monitor points evaluates effects of management practices on yield. An example based upon cotton production demonstrates the methodology. Additional strategies for designing studies in commercial cotton fields involving spatial information are discussed
UTILIZATION OF THE LINE-INTERCEPT METHOD TO ESTIMATE THE COVERAGE, DENSITY, AND AVERAGE LENGTH OF ROW SKIPS IN COTTON AND OTHER ROW CROPS
In row crops, a skip is a length of row within the drill where the crop has failed to establish. If the number of skips and their mean length per acre becomes too high, then considerable losses in crop yield occur. Frequently, farmers are faced with the decision to replant a crop which has row skips. To make the best decision, reliable estimates of the stand loss due to skips must be available. In making this decision, three parameters are useful: the percent of the area per acre that is skipped, the number of individual skips (that is, density) per acre, and the mean row length per skip. The line-intercept method for the sampling of two-dimensional objects (particles) can be used to obtain estimates of these parameters. The method is illustrated with an example from a cotton field
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