8,937 research outputs found
Parasitism of \u3ci\u3ePlathypena Scabra\u3c/i\u3e (Lepidoptera: Noctuidae) by \u3ci\u3eSinophorus Teratis\u3c/i\u3e (Hymenoptera: Ichneumonidae)
(excerpt)
A study was conducted at the Ecology Research Center, Miami University, Butler County, Ohio, during the summer of 1990 to examine the effects of strip intercropping sorghum and soybean on the occurrence of parasitoids and incidence of disease in larvae ofthe green cloverworm, Plathypena scabra (F.) (Lepidoptera: Noctuidae), a sporadic pest of soybeans. The details of the experimental design and results are reported elsewhere (Williams et al. 1995)
Binary Neutron Star Merger Remnants as Sources of Cosmic Rays Below the "Ankle"
We investigate non-thermal electron and nuclei energy losses within the
binary neutron star merger remnant produced by the event GW170817. The lack of
a cooling feature within the detected synchrotron emission from the source is
used to constrain the magnetic field at the mG level, assuming that this
emission is electron synchrotron in origin, and that the accelerated spectrum
in the electrons follows the form . The level of
subsequent gamma-ray emission from the source is demonstrated to provide a
further constraint on the source magnetic field strength. We also put forward
alternative strong (G) magnetic field scenarios able to support this
emission. For such stronger fields, the photo-disintegration of non-thermal
nuclei within the source is considered, and a bottleneck period of 5-30
days is found when this process peaks. We find that this class of source is in
principle able to support the population of cosmic rays detected at Earth below
the "ankle".Comment: Accepted for publication in Astropart. Phy
The application of time-series MODIS NDVI profiles for the acquisition of crop information across Afghanistan
We investigated and developed a prototype crop information system integrating 250 m Moderate Resolution Imaging Spectroradiometer (MODIS) normalized difference vegetation index (NDVI) data with other available remotely sensed imagery, field data, and knowledge as part of a wider project monitoring opium and cereal crops. NDVI profiles exhibited large geographical variations in timing, height, shape, and number of peaks, with characteristics determined by underlying crop mixes, growth cycles, and agricultural practices. MODIS pixels were typically bigger than the field sizes, but profiles were indicators of crop phenology as the growth stages of the main first-cycle crops (opium poppy and cereals) were in phase. Profiles were used to investigate crop rotations, areas of newly exploited agriculture, localized variation in land management, and environmental factors such as water availability and disease. Near-real-time tracking of the current years’ profile provided forecasts of crop growth stages, early warning of drought, and mapping of affected areas. Derived data products and bulletins provided timely crop information to the UK Government and other international stakeholders to assist the development of counter-narcotic policy, plan activity, and measure progress. Results show the potential for transferring these techniques to other agricultural systems
Strongly incoherent gravity
While most fundamental interactions in nature are known to be mediated by
quantized fields, the possibility has been raised that gravity may behave
differently. Making this concept precise enough to test requires consistent
models. Here we construct an explicit example of a theory where a
non-entangling version of an arbitrary two-body potential arises from
local measurements and feedback forces. While a variety of such theories exist,
our construction causes particularly strong decoherence compared to more subtle
approaches. Regardless, expectation values of observables obey the usual
classical dynamics, while the interaction generates no entanglement. Applied to
the Newtonian potential, this produces a non-relativistic model of gravity with
fundamental loss of unitarity. The model contains a pair of free parameters, a
substantial range of which is not excluded by observations to date. As an
alternative to testing entanglement properties, we show that the entire
remaining parameter space can be tested by looking for loss of quantum
coherence in small systems like atom interferometers coupled to oscillating
source masses.Comment: 15 pages + appendices, 3 figure
Dynamical Decompactification and Three Large Dimensions
We study string gas dynamics in the early universe and seek to realize the
Brandenberger - Vafa mechanism - a goal that has eluded earlier works - that
singles out three or fewer spatial dimensions as the number which grow large
cosmologically. Considering wound string interactions in an impact parameter
picture, we show that a strong exponential suppression in the interaction rates
for d > 3 spatial dimensions reflects the classical argument that string
worldsheets generically intersect in at most four spacetime dimensions. This
description is appropriate in the early universe if wound strings are heavy -
wrapping long cycles - and diluted. We consider the dynamics of a string gas
coupled to dilaton-gravity and find that a) for any number of dimensions the
universe generically stays trapped in the Hagedorn regime and b) if the
universe fluctuates to a radiation regime any residual winding modes are
diluted enough so that they freeze-out in d > 3 large dimensions while they
generically annihilate for d = 3. In this sense the Brandenberger-Vafa
mechanism is operative.Comment: 20 pages, 2 figures, minor changes, updated figures, as will appear
in Phys.Rev.
Characterization of a graphite epoxy optical bench during thermal vacuum cycling
In-situ monitoring of the Wide-Field/Planetary Camera, a Hubble Space Telescope science instrument, was performed in a vacuum environment to better understand the formation of ice on cooled optical detectors. Several diagnostic instruments were mounted on an access plate to view the interior of the instrument housing and the graphite epoxy optical bench. The instrumentation chosen and the rationale for choosing the instrumentation are discussed. In addition, the performance of the instrumentation during monitoring operations is discussed
Survey and monitoring of opium poppy and wheat in Afghanistan: 2003-2009
An integrated application of remote-sensing technology was devised and applied in Afghanistan during 2003–2009 providing critical information on cereal and poppy cultivation and poppy eradication. The results influenced UK and international policy and counter-narcotics actions in Afghanistan
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Large-effect flowering time mutations reveal conditionally adaptive paths through fitness landscapes in Arabidopsis thaliana.
Contrary to previous assumptions that most mutations are deleterious, there is increasing evidence for persistence of large-effect mutations in natural populations. A possible explanation for these observations is that mutant phenotypes and fitness may depend upon the specific environmental conditions to which a mutant is exposed. Here, we tested this hypothesis by growing large-effect flowering time mutants of Arabidopsis thaliana in multiple field sites and seasons to quantify their fitness effects in realistic natural conditions. By constructing environment-specific fitness landscapes based on flowering time and branching architecture, we observed that a subset of mutations increased fitness, but only in specific environments. These mutations increased fitness via different paths: through shifting flowering time, branching, or both. Branching was under stronger selection, but flowering time was more genetically variable, pointing to the importance of indirect selection on mutations through their pleiotropic effects on multiple phenotypes. Finally, mutations in hub genes with greater connectedness in their regulatory networks had greater effects on both phenotypes and fitness. Together, these findings indicate that large-effect mutations may persist in populations because they influence traits that are adaptive only under specific environmental conditions. Understanding their evolutionary dynamics therefore requires measuring their effects in multiple natural environments
Testing quantum gravity with interactive information sensing
We suggest a test of a central prediction of perturbatively quantized general
relativity: the coherent communication of quantum information between massive
objects through gravity. To do this, we introduce the concept of interactive
quantum information sensing, a protocol tailored to the verification of
dynamical entanglement generation between a pair of systems. Concretely, we
propose to monitor the periodic wavefunction collapse and revival in an atomic
interferometer which is gravitationally coupled to a mechanical oscillator. We
prove a theorem which shows that, under the assumption of time-translation
invariance, this collapse and revival is possible if and only if the
gravitational interaction forms an entangling channel. Remarkably, as this
approach improves at moderate temperatures and relies primarily upon atomic
coherence, our numerical estimates indicate feasibility with current devices.Comment: 24 pages + appendices, 6 figure
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