An electric-field representation of the harmonic XY model

The two-dimensional harmonic XY (HXY) model is a spin model in which the classical spins interact via a piecewise parabolic potential. We argue that the HXY model should be regarded as the canonical classical lattice spin model of phase fluctuations in two-dimensional condensates, as it is the simplest model that guarantees the modular symmetry of the experimental systems. Here we formulate a lattice electric-field representation of the HXY model and contrast this with an analogous representation of the Villain model and the two-dimensional Coulomb gas with a purely rotational auxiliary field. We find that the HXY model is a spin-model analogue of a lattice electric-field model of the Coulomb gas with an auxiliary field, but with a temperature-dependent vacuum (electric) permittivity that encodes the coupling of the spin vortices to their background spin-wave medium. The spin vortices map to the Coulomb charges, while the spin-wave fluctuations correspond to auxiliary-field fluctuations. The coupling explains the striking differences in the high-temperature asymptotes of the specific heats of the HXY model and the Coulomb gas with an auxiliary field. Our results elucidate the propagation of effective long-range interactions throughout the HXY model (whose interactions are purely local) by the lattice electric fields. They also imply that global spin-twist excitations (topological-sector fluctuations) generated by local spin dynamics are ergodically excluded in the low-temperature phase. We discuss the relevance of these results to condensate physics.Comment: 13 pages, 10 figure

Topological-sector fluctuations and ergodicity breaking at the Berezinskii-Kosterlitz-Thouless transition

The Berezinskii-Kosterlitz-Thouless (BKT) phase transition drives the unbinding of topological defects in many two-dimensional systems. In the two-dimensional Coulomb gas, it corresponds to an insulator-conductor transition driven by charge deconfinement. We investigate the global topological properties of this transition, both analytically and by numerical simulation, using a lattice-field description of the two-dimensional Coulomb gas on a torus. The BKT transition is shown to be an ergodicity breaking between the topological sectors of the electric field, which implies a definition of topological order in terms of broken ergodicity. The breakdown of local topological order at the BKT transition leads to the excitation of global topological defects in the electric field, corresponding to different topological sectors. The quantized nature of these classical excitations, and their strict suppression by ergodicity breaking in the low-temperature phase, afford striking global signatures of topological-sector fluctuations at the BKT transition. We discuss how these signatures could be detected in experiments on, for example, magnetic films and cold-atom systems.Comment: 11 pages, 6 figure

Canine Heartworm Infection and Prophylaxis use among Pet Caretakers from the Cumberland Gap Region of Tennessee, USA

The prevalence of infection with canine heartworm (CHW), Dirofilaria immitis, continues to increase across the United States, regardless of the availability of effective and affordable prophylactic products. Current reports of CHW prevalence as estimated by the Companion Animal Parasite Council (CAPC) are thought to under-represent the true magnitude of the issue because pet dogs that do not receive regular veterinary care are often excluded. This study estimated the prevalence of CHW in pet dogs and associated prophylaxis use in pet dogs in the Cumberland Gap Region with a combined doorstep diagnostic testing approach and caretaker survey. Dogs tested (n = 258) during the summers of 2018 and 2019 revealed a 2.3% (6/258) prevalence in the pet dog population with 33% (2/6) being microfilaremic. Questionnaire data from caretaker interviews revealed that 41.8% (108/258) of the dogs were not receiving CHW prophylaxis. Significant predictors of CHW prophylaxis use identified through logistic regression included pet caretaker awareness of CHW as an important health issue and the use of veterinary services in the year preceding participation in the survey. These results underscore the importance of veterinary-mediated client interaction to create risk awareness of CHW disease and association with prophylaxis compliance

Phase order in superfluid helium films

Classic experimental data on helium films are transformed to estimate a finite-size phase order parameter that measures the thermal degradation of the condensate fraction in the two-dimensional superfluid. The order parameter is found to evolve thermally with the exponent $\beta = 3 \pi^2/128$, a characteristic, in analogous magnetic systems, of the Berezinskii-Kosterlitz-Thouless (BKT) phase transition. Universal scaling near the BKT fixed point generates a collapse of experimental data on helium and ferromagnetic films, and implies new experiments and theoretical protocols to explore the phase order. These results give a striking example of experimental finite-size scaling in a critical system that is broadly relevant to two-dimensional Bose fluids.Comment: 6 pages, 2 figure

Banishing AdS ghosts with a UV cutoff

A recent attempt to make sense of scalars in AdS with "Neumann boundary conditions" outside of the usual BF-window $-(d/2)^2 < m^2 l^2 < -(d/2)^2 + 1$ led to pathologies including (depending on the precise context) either IR divergences or the appearance of ghosts. Here we argue that such ghosts may be banished by imposing a UV cutoff. It is also possible to achieve this goal in certain UV completions. An example is the above AdS theory with a radial cutoff supplemented by particular boundary conditions on the cutoff surface. In this case we explicitly identify a region of parameter space for which the theory is ghost free. At low energies, this theory may be interpreted as the standard dual CFT (defined with "Dirichlet" boundary conditions) interacting with an extra scalar via an irrelevant interaction. We also discuss the relationship to recent works on holographic fermi surfaces and quantum criticality.Comment: 20 pages, 9 figure

Symmetry Breaking Phase Transitions in ABJM Theory with a Finite U(1) Chemical Potential

We consider the U(1) charged sector of ABJM theory at finite temperature, which corresponds to the Reissner-Nordstrom AdS black hole in the dual type IIA supergravity description. Including back-reaction to the bulk geometry, we show that phase transitions occur to a broken phase where SU(4) R-symmetry of the field theory is broken spontaneously by the condensation of dimension one or two operators. We show both numerically and analytically that the relevant critical exponents for the dimension one operator agree precisely with those of mean field theory in the strongly coupled regime of the large N planar limit.Comment: 22 pages, 6 figures, typos corrected, references added, improved figures, minor changes, accepted for publication in Phys. Rev.

Molecular and Biological Epidemiology of Mosquito Vecors for Canine Heartworm Infection in the Cumberland Gap Region

Canine heartworm (Dirofilaria immitis), is a nematode parasite that infects canines, both wild and domestic and other vertebrate hosts like ferrets, otters, and cats worldwide. The disease, dirofilariasis, can be fatal in advanced stages if untreated and is recognized as a significant concern in veterinary medicine. Canine heartworm has been reported in 49 states of the United States (U.S.) and is considered enzootic. The nematode lifecycle is dependent upon canines infected with adult worms that produce microfilaria, the vermiform embryonic stage, that circulate in the peripheral blood of the host and the mosquito vectors that ingest them taking a blood meal from the infected canine. The three-fold objective of this research was to (1) conduct a biological survey and inventory of the mosquito population in the Cumberland Gap Region (CGR) of southern Appalachia; (2) determine the mosquito species infected with Dirofilaria immitis larvae; (3) estimate the prevalence of D. immitis in the mosquito population for its transmission to pet dogs in communities within the CGR. Adult female questing and gravid mosquitos (n=2455) (representing 778 pools) were collected each year from May to September during 2017, 2018, and 2019 in an area encompassing the campus of Lincoln Memorial University in Harrogate, TN focused in Claiborne county. This was accomplished using CO2 baited CDC gravid and questing traps. Three collection zones were the focus of this research. Collection area A had high residential density, with ~42 homes per km2. It had sparse forest cover and a relatively high number of free-roaming dogs observed during the study. Collection area B had moderate residential density, with ~13 homes per km2 with dense forest cover and frequent free-roaming dogs were observed during the study. Collection area C had the lowest residential density, with ~7 homes per km2 with a mix of dense forest cover proximal to a local dog park. This location has transient dog visitation and no free-roaming dogs were noted during the study. Collected mosquitoes were euthanized by freezing overnight at -20°C and sorted into pools by species based on collection site and date. There were 2455 collected specimens representing 5 main species: Culex pipiens (n=521, pools=175), Aedes albopictus (n=460, pools=138), Aedes japonicus (n=417, pools=111), Anopheles punctipennis (n=186, pools=74) and Aedes vexans (n=172, pools=62). Another species significant to this study but found less frequently was Anopheles quadrimaculatus (n=13, pools=7). Culex pipiens was the most prevalent mosquito species accounting for 24.05% of the species collected overall. Pools of sorted mosquitoes were assayed via PCR to detect the presence of D. immitis DNA. Five (0.57%) of 778 assayed pools were positive. The positive pooled species identified were: An. quadrimaculatus (2 pools), Ae. albopictus, Ae japonicus, and Ae. vexans. All these species are recognized as established vectors of CHW in Tennessee. The identification of Ae. japonicus in this study is the 1st report of its vector potential for transmission of CHW in Eastern Tennessee

A Retrospective Examination of Paleoparasitology and its Establishment in the Journal of Parasitology

Volume 95 (2009) of the Journal of Parasitology represented a significant benchmark in the history of paleoparasitology when it received on the cover formal recognition as a topical area for publication. This retrospective examination chronicles the emergence of paleoparasitology, from its origins as an adjunct contribution to the study of prehistoric human populations to its modern expression as a sub-disciplinary interest. The aim of paleoparasitology is to elucidate the temporal and spatial dimensions of parasitism from the fossil record of human and non-human host populations

Genetic Markers Involved in Macrocyclic Lactone Resistance in Dirofilaria immitis and Estimation of Heartworm Prevalence in Resident Canine Populations of the Cumberland Gap Region of Kentucky, Tennessee, and Virginia.

Infection with heartworm (Dirofilaria immitis), is a significant cause of disease in companion animals worldwide. Macrocyclic lactones (MLs) have been the standard treatment for heartworm prevention for the last 25 years. Although widely used and highly effective, recent studies have shown a potential loss of efficacy. Investigations suggest the involvement of a single-nucleotide polymorphisms (SNPs) of a gene encoding a fragment of P-glycoprotein (P-gp) within the Dirofilaria. immitis genome. This reveals a potential relationship between SNP frequencies within the P-gp gene and ML resistance. The prevalence of heartworm infection in the Cumberland Gap Region (CGR) is reported to be 2.73% based on dogs tested at veterinary clinics. This may underrepresent the true prevalence of infection because up to 55% of pet dogs in the area do not receive regular veterinary care. The goal of this study was to obtain a more accurate estimate of the true prevalence of heartworm infection and the microfilaremic status of infected canine hosts and survey the population of D. immitis infecting dogs in the CGR for the existence of the single nucleotide polymorphism within P-glycoprotein and to. We found an overall prevalence in the CGR of 5.04%, higher than what was reported. Additionally, we did not find the GG-GG genotype that is suspected to be involved with ML resistance, but we did find a SNP of GA-GG at the loci of interest

A Survey of Pet Caretakers on the Use and Perceptions Regarding Heartworm Prophylaxis for Prevention of Canine Heartworm Disease

Canine heartworm disease (CHWD) is caused by infection with the nematode parasite Dirofilaria immitis transmitted through the bite of a mosquito carrying the infective stage larva. The disease is insidious in its onset and almost 100% preventable with the use of highly effective pharmaceutical compounds that target the migrating larval stage acquired from the mosquito. However, use of canine heartworm prophylaxis among pet dog caretakers is not universally accepted and sometimes viewed with skepticism. Previous research conducted in the Cumberland Gap Region (CGR) indicated that 41.8% of dog owning individuals do not use prophylactic products. In this study, we surveyed pet dog caretakers across the United States from October 2021-February 2022 to determine reasons for the use or non-use of canine heartworm prophylaxis to prevent CHWD. Results of 305 responses were analyzed from 31 states in the domestic United States and Puerto Rico (PR). Among survey participants, 22% of dog caretakers chose not to give their pets heartworm prophylaxis. Pet dog caretakers in the US chose not to give their pets canine heartworm prophylaxis for economic reasons (46%, 21/46), environmental factors (24%,11/46), subscribe to beliefs associated with a holistic approach to prevention (9%,4/46),low perceived risk of CHWD (6.5%,3/46),or other reasons (28%,13/46).These results can aid veterinary professionals to address the educational challenges associated with heartworm prophylaxis and disease to increase their use and gain better rapport with clients