1,842 research outputs found
First Record of Pseudorabies in Feral Swine in Nebraska
In 2007, two new populations of feral swine were discovered in Nance and Valley counties, Nebraska, USA. Necropsies and serologic testing was done on two individuals from the Nance County herd. Results indicated that a lactating sow had positive antibodies for pseudorabies virus (PRV). Investigations conducted by Nebraska Game and Parks Commission Law Enforcement division confirmed that the infected individual was transported illegally to Nebraska, USA, from Texas, USA. All domestic swine herds located within an 8 km radius of the infected individual tested negative for antibodies to PRV. Our results provide a clear example of how diseases can spread because of anthropogenic activities and highlight the need for disease surveillance and monitoring in the import of invasive species
Generic scaling relation in the scalar model
The results of analysis of the one--loop spectrum of anomalous dimensions of
composite operators in the scalar model are presented. We give the
rigorous constructive proof of the hypothesis on the hierarchical structure of
the spectrum of anomalous dimensions -- the naive sum of any two anomalous
dimensions generates a limit point in the spectrum. Arguments in favor of the
nonperturbative character of this result and the possible ways of a
generalization to other field theories are briefly discussed.Comment: 15 pages, Latex, 50 K
Expanding the Capability of Satellite Operations using a Global Federated Ground Station Network
Small-scale spaceflight programs such as those found at universities and start-up companies may operate satellites from a single ground station. This station’s location may not be optimal for radio communications, and a single station limits the contact time available to conduct operations. The idea of a global federated ground station network (FGN) has been theorized in the past, and with today’s wide-spread internet connectivity it is now possible for such a network to exist. One example of an FGN that is functioning today is an open-source project called SatNOGS. The Michigan eXploration Laboratory (MXL) at the University of Michigan has applied the benefits of this network to enhance operations of their Tandem Beacon Experiment (TBEx) CubeSat mission by gathering 2.2x the beacons gathered by their home station alone. 93% of those additional beacons were collected by six SatNOGS stations. Augmenting MXL’s home station with these six stations increases access time to the TBEx satellites by a factor of 5 to15. This increased temporal coverage also enabled MXL operators to identify their spacecraft after deployment and correct an error causing the TBEx radios to function intermittently, saving the mission in its earliest days
The first cosmic ray albedo proton map of the Moon
[1] Neutrons emitted from the Moon are produced by the impact of galactic cosmic rays (GCRs) within the regolith. GCRs are high-energy particles capable of smashing atomic nuclei in the lunar regolith and producing a shower of energetic protons, neutrons and other subatomic particles. Secondary particles that are ejected out of the regolith become “albedo” particles. The neutron albedo has been used to study the hydrogen content of the lunar regolith, which motivates our study of albedo protons. In principle, the albedo protons should vary as a function of the input GCR source and possibly as a result of surface composition and properties. During the LRO mission, the total detection rate of albedo protons between 60 MeV and 150 MeV has been declining since 2009 in parallel with the decline in the galactic cosmic ray flux, which validates the concept of an albedo proton source. On the other hand, the average yield of albedo protons has been increasing as the galactic cosmic ray spectrum has been hardening, consistent with a disproportionately stronger modulation of lower energy GCRs as solar activity increases. We construct the first map of the normalized albedo proton emission rate from the lunar surface to look for any albedo variation that correlates with surface features. The map is consistent with a spatially uniform albedo proton yield to within statistical uncertainties
Scheme Independence and the Exact Renormalization Group
We compute critical exponents in a symmetric scalar field theory in
three dimensions, using Wilson's exact renormalization group equations expanded
in powers of derivatives. A nontrivial relation between these exponents is
confirmed explicitly at the first two orders in the derivative expansion. At
leading order all our results are cutoff independent, while at next-to-leading
order they are not, and the determination of critical exponents becomes
ambiguous. We discuss the possible ways in which this scheme ambiguity might be
resolved.Comment: 15 pages, TeX with harvmac, 2 figures in compressed postscript;
presentation of first section revised, several minor errors corrected, two
references adde
Radiation modeling in the Earth and Mars atmospheres using LRO/CRaTER with the EMMREM Module
Abstract We expand upon the efforts of Joyce et al. (2013), who computed the modulation potential at the Moon using measurements from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument on the Lunar Reconnaissance Orbiter (LRO) spacecraft along with data products from the Earth-Moon-Mars Radiation Environment Module (EMMREM). Using the computed modulation potential, we calculate galactic cosmic ray (GCR) dose and dose equivalent rates in the Earth and Mars atmospheres for various altitudes over the course of the LRO mission. While we cannot validate these predictions by directly comparable measurement, we find that our results conform to expectations and are in good agreement with the nearest available measurements and therefore may be used as reasonable estimates for use in efforts in risk assessment in the planning of future space missions as well as in the study of GCRs. PREDICCS (Predictions of radiation from REleASE, EMMREM, and Data Incorporating the CRaTER, COSTEP, and other solar energetic particles measurements) is an online system designed to provide the scientific community with a comprehensive resource on the radiation environments of the inner heliosphere. The data products shown here will be incorporated into PREDICCS in order to further this effort and daily updates will be made available on the PREDICCS website (http://prediccs.sr.unh.edu). Key Points We model GCR dose and dose equivalent rates in Earth and Mars atmospheres Dose rates are in reasonable agreement with nearby measurements Data products will soon be made available on PREDICCS website
Universality and quantum effects in one-component critical fluids
Non-universal scale transformations of the physical fields are extended to
pure quantum fluids and used to calculate susceptibility, specific heat and the
order parameter along the critical isochore of He3 near its liquid-vapor
critical point. Within the so-called preasymptotic domain, where the Wegner
expansion restricted to the first term of confluent corrections to scaling is
expected valid, the results show agreement with the experimental measurements
and recent predictions, either based on the minimal-substraction
renormalization and the massive renormalization schemes within the
-model, or based on the crossover parametric equation of
state for Ising-like systems
Magic-Angle Semimetals with Chiral Symmetry
We construct and solve a two-dimensional, chirally symmetric model of Dirac
cones subjected to a quasiperiodic modulation. In real space, this is realized
with a quasiperiodic hopping term. This hopping model, as we show, at the Dirac
node energy has a rich phase diagram with a semimetal-to-metal phase transition
at intermediate amplitude of the quasiperiodic modulation, and a transition to
a phase with a diverging density of states and sub-diffusive transport when the
quasiperiodic hopping is strongest. We further demonstrate that the
semimetal-to-metal phase transition can be characterized by the multifractal
structure of eigenstates in momentum space and can be considered as a unique
"unfreezing" transition. This unfreezing transition in momentum space generates
flat bands with a dramatically renormalized bandwidth in the metallic phase
similar to the phenomena of the band structure of twisted bilayer graphene at
the magic angle. We characterize the nature of this transition numerically as
well as analytically in terms of the formation of a band of topological zero
modes. For pure quasiperiodic hopping, we provide strong numerical evidence
that the low-energy density of states develops a divergence and the eigenstates
exhibit Chalker (quantum-critical) scaling despite the model not being random.
At particular commensurate limits the model realizes higher-order topological
insulating phases. We discuss how these systems can be realized in experiments
on ultracold atoms and metamaterials.Comment: 20+4 pages, 24 figures, published versio
Locating and eliminating feral swine from a large area of fragmented mixed forest and agriculture habitats in north-central USA
Illinois is one of the US states where elimination of feral swine (Sus scrofa) was determined practical, as only a few isolated populations were established. A particularly important step towards feral swine elimination from Illinois was to eliminate the population in Fulton County. We describe the approaches applied to systematically detect, locate, and eliminate feral swine in a successful county-wide elimination. Detecting and locating feral swine was facilitated by extensive outreach activities, aerial surveys to locate crop damage, and use of camera traps placed over bait in areas where reports, sign, or crop damage occurred. The population was eliminated after 376 feral swine were removed from 2009 to 2016 by trapping, sharpshooting over bait, and aerial shooting. Aerial surveys efficiently located feral swine activity over wide areas during times of the crop cycle when damage would occur and would be most distinguishable from other damage sources. Two applications of aerial shooting in 2014 were particularly efficient for rapidly eliminating most remaining feral swine after they had become difficult to locate and remove. Persistent efforts thereafter led to the successful elimination of feral swine in Fulton County by 2016.We believe this is the first documentation of a widespread feral swine elimination in mixed agriculture and forest habitats
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