3,207 research outputs found
Jets and Jet Multiplicities in High Energy Photon-Nucleon Inetraction:
We discuss the theory of jet events in high-energy photon-proton interactions
using a model which gives a good description of the data available on total
inelastic cross sections up to =210 GeV. We show how to
calculate the jet cross sections and jet multiplicities and give predictions
for these quantities for energies appropriate for experiments at the HERA
collider and for very high energy cosmic ray observations.Comment: 12 pages + 4 figs, MAD/TH/92-8, submitted to Phys. Rev. D(Rapid
Communications), figs. available on request from [email protected]
Diffraction-limited Subaru imaging of M82: sharp mid-infrared view of the starburst core
We present new imaging at 12.81 and 11.7 microns of the central ~40"x30"
(~0.7x0.5 kpc) of the starburst galaxy M82. The observations were carried out
with the COMICS mid-infrared (mid-IR) imager on the 8.2m Subaru telescope, and
are diffraction-limited at an angular resolution of <0".4. The images show
extensive diffuse structures, including a 7"-long linear chimney-like feature
and another resembling the edges of a ruptured bubble. This is the clearest
view to date of the base of the kpc-scale dusty wind known in this galaxy.
These structures do not extrapolate to a single central point, implying
multiple ejection sites for the dust. In general, the distribution of dust
probed in the mid-IR anticorrelates with the locations of massive star clusters
that appear in the near-infrared. The 10-21 micron mid-IR emission,
spatially-integrated over the field of view, may be represented by hot dust
with temperature of ~160 K. Most discrete sources are found to have extended
morphologies. Several radio HII regions are identified for the first time in
the mid-IR. The only potential radio supernova remnant to have a mid-IR
counterpart is a source which has previously also been suggested to be a weak
active galactic nucleus. This source has an X-ray counterpart in Chandra data
which appears prominently above 3 keV and is best described as a hot (~2.6 keV)
absorbed thermal plasma with a 6.7 keV Fe K emission line, in addition to a
weaker and cooler thermal component. The mid-IR detection is consistent with
the presence of strong [NeII]12.81um line emission. The broad-band source
properties are complex, but the X-ray spectra do not support the active
galactic nucleus hypothesis. We discuss possible interpretations regarding the
nature of this source.Comment: Accepted for publication in PASJ Subaru special issue. High
resolution version available temporarily at
http://www.astro.isas.jaxa.jp/~pgandhi/pgandhi_m82.pd
New Reports of Exotic and Native Ambrosia and Bark Beetle Species (Coleoptera: Curculionidae: Scolytinae) From Ohio
In a 2007 survey of ambrosia and bark beetles (Coleoptera: Curculionidae: Scolytinae) along a transect in northeastern Ohio, we collected six exotic and three native species not previously reported from the state. These species include the exotic ambrosia beetles Ambrosiodmus rubricollis (Eichhoff), Dryoxylon onoharaensum (Murayama), Euwallacea validus (Eichhoff), Xyleborus californicus Wood, Xyleborus pelliculosusEichhoff, and Xylosandrus crassiusculus (Motschulsky). The native ambrosia beetle Corthylus columbianus Hopkins, and the native bark beetles Dryocoetes autographus (Ratzeburg) and Hylastes tenuis Eichhoff are also reported from Ohio for the first time. Our study suggests a northward range expansion for five of the six exotic species including, X. crassiusculus, which is an important pest of nursery and orchard crops in the southeastern United States
High-energy Atmospheric Muon Flux Expected at India-Based Neutrino Observatory
We calculate the zenith-angle dependence of conventional and prompt
high-energy muon fluxes at India-Based Neutrino Observatory (INO) depth. This
study demonstrates a possibility to discriminate models of the charm
hadroproduction including the low-x QCD behaviour of hadronic cross-sections
relevant at very high energies.Comment: 10 pages. 8 figures, 3 table
TeV Strings and the Neutrino-Nucleon Cross Section at Ultra-high Energies
In scenarios with the fundamental unification scale at the TeV one expects
string excitations of the standard model fields at accessible energies. We
study the neutrino-nucleon cross section in these models. We show that duality
of the scattering amplitude forces the existence of a tower of massive
leptoquarks that mediate the process in the s-channel. Using the narrow-width
approximation we find a sum rule for the production rate of resonances with
different spin at each mass level. We show that these contributions can
increase substantially the standard model neutrino-nucleon cross section,
although seem insufficient in order to explain the cosmic ray events above the
GZK cutoff energy.Comment: 10 pages, 1 figure, version to appear in PR
An Advanced Real Time Lead RF-MEMS Based Switch Design for AI Applications
The artificial intelligence-based MEMS switch designs have been led technology in present micro-electronic applications. The 4G and 5G communication hardware networks have working been through RF-MEMS switches. The earlier MEMS deigns are outdated in terms of functionality and compatibility, so that a realistic RF-MEMS based advanced configurations are compulsory for future electronic applications. In this research work 2 different shunt-capacitive type configurations have been implemented and those are verified on COMSOL Multi-physics toolbox as well as functionality been verified on HFSS software tool. The electromechanical properties of proposed shunt type RF-MEMS switch attained more perfection in functionality compared to past configurations. The implemented switching model has uniform meandering and derives pull-in-voltage of 18.5v along with 1.2xs switching time. The 2nd type shunt RF-MEMS model has been generated pull-in-voltage of 25.5v and isolation loss of 37.20. The performance metrics like Length 25.34 µm, Width 28.92 µm and Thickness 34.42 µm had been improved compared to previous models. The deigned shunt-capacitive type RF-MEMS models are most prominent in operation and offering advanced microelectronics applications
An Advanced Real Time Lead RF-MEMS Based Switch Design for AI Applications
The artificial intelligence-based MEMS switch designs have been led technology in present micro-electronic applications. The 4G and 5G communication hardware networks have working been through RF-MEMS switches. The earlier MEMS deigns are outdated in terms of functionality and compatibility, so that a realistic RF-MEMS based advanced configurations are compulsory for future electronic applications. In this research work 2 different shunt-capacitive type configurations have been implemented and those are verified on COMSOL Multi-physics toolbox as well as functionality been verified on HFSS software tool. The electromechanical properties of proposed shunt type RF-MEMS switch attained more perfection in functionality compared to past configurations. The implemented switching model has uniform meandering and derives pull-in-voltage of 18.5v along with 1.2xs switching time. The 2nd type shunt RF-MEMS model has been generated pull-in-voltage of 25.5v and isolation loss of 37.20. The performance metrics like Length 25.34 µm, Width 28.92 µm and Thickness 34.42 µm had been improved compared to previous models. The deigned shunt-capacitive type RF-MEMS models are most prominent in operation and offering advanced microelectronics applications
Prospecting Period Measurements with LSST - Low Mass X-ray Binaries as a Test Case
The Large Synoptic Survey Telescope (LSST) will provide for unbiased sampling
of variability properties of objects with mag 24. This should allow for
those objects whose variations reveal their orbital periods (), such
as low mass X-ray binaries (LMXBs) and related objects, to be examined in much
greater detail and with uniform systematic sampling. However, the baseline LSST
observing strategy has temporal sampling that is not optimised for such work in
the Galaxy. Here we assess four candidate observing strategies for measurement
of in the range 10 minutes to 50 days. We simulate multi-filter
quiescent LMXB lightcurves including ellipsoidal modulation and stochastic
flaring, and then sample these using LSST's operations simulator (OpSim) over
the (mag, ) parameter space, and over five sightlines sampling a range
of possible reddening values. The percentage of simulated parameter space with
correctly returned periods ranges from 23 %, for the current baseline
strategy, to 70 % for the two simulated specialist strategies. Convolving
these results with a distribution, a modelled Galactic spatial
distribution and reddening maps, we conservatively estimate that the most
recent version of the LSST baseline strategy will allow determination
for 18 % of the Milky Way's LMXB population, whereas strategies that do
not reduce observations of the Galactic Plane can improve this dramatically to
32 %. This increase would allow characterisation of the full binary
population by breaking degeneracies between suggested distributions
in the literature. Our results can be used in the ongoing assessment of the
effectiveness of various potential cadencing strategies.Comment: Replacement after addressing minor corrections from the referee -
mainly improvements in clarificatio
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