2,107 research outputs found
Field Monitoring of X-Disease Leafhopper Vectors (Homoptera: Cicadellidae) and Infected Chokecherry in Michigan Peach and Cherry Orchards
Populations of leafhopper vectors of X-disease, a major disease problem of the Michigan peach industry, were monitored by yellow sticky board traps and sweepnet samples during 1985 and 1986. Abundance of known leafhopper vectors varied throughout the stone fruit belt of Michigan, with Paraphlepsius irroratus common in the southwest Lower Peninsula, but representing 73.1 % of all known vectors found. Other commonly found vectors included Scaphytopius acutus (22%), Colladonus clitellarius (1.5\u27k). and Norvellina seminuda (3.4%). Yellow sticky boards were the best monitoring method used. accounting for 90.3% of all vectors captured. The appearance of X-disease symptoms on chokecherry throughout the survey area indicated transmission between wild hosts was occurring in areas where X-disease is not yet a major problem to growers
QICS work package 1: migration and trapping of CO2 from a reservoir to the seabed or land surface
Natural CO2 seeps can be used as analogues for studies into surface flux and impact resulting from leaking engineered geological CO2 reservoirs. However their long-lived nature often means that the local environment has either adapted or evolvedaround the seepage site. The ‘Quantifying Impact of carbon storage’ (QICS) experiment provides the solution to this issue by releasing CO2 into an environment previously untouched by CO2. Work Package 1 (WP1) of the QICS project is primarily concerned with the migration of CO2 in the subsurface and how to relate the results of the relatively shallow experiment to a full storage scale setting in the UK North Sea. The main objectives of WP1 are to investigate potential leakage pathways from the reservoir to the surface, determine possible leakage rates and assess the potential volumes of leaked CO2 that can reach the surface environment
Dark Matter with Topological Defects in the Inert Doublet Model
We examine the production of dark matter by decaying topological defects in
the high mass region of the Inert Doublet Model,
extended with an extra U(1) gauge symmetry. The density of dark matter states
(the neutral Higgs states of the inert doublet) is determined by the interplay
of the freeze-out mechanism and the additional production of dark matter states
from the decays of topological defects, in this case cosmic strings. These
decays increase the predicted relic abundance compared to the standard
freeze-out only case, and as a consequence the viable parameter space of the
Inert Doublet Model can be widened substantially. In particular, for a given
dark matter annihilation rate lower dark matter masses become viable. We
investigate the allowed mass range taking into account constraints on the
energy injection rate from the diffuse -ray background and Big Bang
Nucleosynthesis, together with constraints on the dark matter properties coming
from direct and indirect detection limits. For the Inert Doublet Model
high-mass region, an inert Higgs mass as low as GeV is permitted.
There is also an upper limit on string mass per unit length, and hence the
symmetry breaking scale, from the relic abundance in this scenario. Depending
on assumptions made about the string decays, the limits are in the range
GeV to GeV.Comment: 27 pages, 3 figures. V2: Published version with references adde
A Real-time Image Reconstruction System for Particle Treatment Planning Using Proton Computed Tomography (pCT)
Proton computed tomography (pCT) is a novel medical imaging modality for
mapping the distribution of proton relative stopping power (RSP) in medical
objects of interest. Compared to conventional X-ray computed tomography, where
range uncertainty margins are around 3.5%, pCT has the potential to provide
more accurate measurements to within 1%. This improved efficiency will be
beneficial to proton-therapy planning and pre-treatment verification. A
prototype pCT imaging device has recently been developed capable of rapidly
acquiring low-dose proton radiographs of head-sized objects. We have also
developed an advanced, fast image reconstruction software based on distributed
computing that utilizes parallel processors and graphical processing units. The
combination of fast data acquisition and fast image reconstruction will enable
the availability of RSP images within minutes for use in clinical settings. The
performance of our image reconstruction software has been evaluated using data
collected by the prototype pCT scanner from several phantoms.Comment: Paper presented at Conference on the Application of Accelerators in
Research and Industry, CAARI 2016, 30 October to 4 November 2016, Ft. Worth,
TX, US
Harvesting Wind Damaged Trees: A Study of the Safety Implications for Fallers and Choker Setters
Hazards occurring to the fallers and chokersetters (breaker-outs) within cable yarder (hauler) crews working in windthr/ow salvage conditions were recorded. Fallers were exposed to considerably more and potentially more serious hazards than fallers working under normal conditions. The most hazardous parts of the faller's job were those of felling, clearing around the tree to be felled and clearing a path to the tree to be felled. The two most dangerous tree types to deal with were "hung-up" and "rootball trees". The choker setters were exposed to a similar number of hazards per cycle as choker setting in normal conditions, but a number of previously undocumented hazards were recorded. The majority of choking hazards (70%) occurred during the "wait" phase of choking with the most frequent hazard being "standing within one tree length of the turn". The information contained in this article may assist other contractors and forest companies faced with the difficult task of harvesting windthr/own trees
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