Transmission-Line Analysis of Epsilon-Near-Zero (ENZ)-Filled Narrow Channels

Following our recent interest in metamaterial-based devices supporting resonant tunneling, energy squeezing and supercoupling through narrow waveguide channels and bends, here we analyze the fundamental physical mechanisms behind this phenomenon using a transmission-line model. These theoretical findings extend our theory, allowing us to take fully into account frequency dispersion and losses and revealing the substantial differences between this unique tunneling phenomenon and higher-frequency Fabry-Perot resonances. Moreover, they represent the foundations for other possibilities to realize tunneling through arbitrary waveguide bends, both in E and H planes of polarization, waveguide connections and sharp abruptions and to obtain analogous effects with geometries arguably simpler to realize.Comment: 35 pages, 9 figure

Louisiana Birds Act as Reservoirs for Antibiotic-resistant Bacteria

Wild birds carry diverse microbial communities, including antibiotic-resistant bacteria (ARB). With the ever-increasing use of antibiotics in agricultural and clinical settings, genes that code for antibiotic resistance in bacteria have been selected for. These bacteria persist in the environment in a culturable state, but little is understood about communities of antibiotic-resistant bacteria in the environment. Birds with predictable behaviors may serve as useful indicators of these communities, and provide insights into how bacterial communities spread and evolve in the environment. To understand the utility of birds as indicators of the presence of antibiotic-resistant bacteria in the environment, we collected bacterial samples from forest birds in a cypress-tupelo/bottomland hardwood forest fragment surrounded by urban Baton Rouge, Louisiana. Densities of total and antibiotic-resistant bacteria varied by bird sex, age group, and foraging guild. Specifically, female birds had a higher prevalence of antibiotic-resistant bacteria than males, juvenile birds carried higher densities of antibiotic-resistant bacteria than adult birds, and tree-foraging birds carried higher densities than did ground-foraging birds. These data suggest that specific behaviors from each group may be associated with higher colonization by antibiotic-resistant bacteria and that birds may be useful indicators of contamination by viable potential pathogens in the environment. In a separate analysis, we sequenced the 16S rRNA gene from almost 100 isolates and used BLASTn analysis to determine the lowest possible taxonomic level for each sequence. We found that there were four orders of bacteria present from all of our samples; Lactobacillales, Pseudomonadales, Bacillales, and Enterbacterales. The Louisiana birds sampled in this study yielded a diverse array of bacteria, and highlighted the importance of future studies of antibiotic-resistant bacteria in birds

Gender assignment in loan words in the history of Icelandic : a synchronic and diachronic analysis

textSome such as Schwink (2004) have analyzed diachronic developments in Germanic gender as a whole, while others like Steinmetz (1985, 2001) and Trosterud (2006) have looked at diachronic changes in grammatical gender in the North Germanic languages. Specifically within the history of Icelandic, Steinmetz and Trosterud both argue for a neuter-default gender system for Old Norse (and for Modern Icelandic). This report looks at loan words from the Old Norse period drawn from historical sources, such as the Heimskringla (History of the Kings of Norway) and Laxdœla Saga, and compares their gender assignment then with their gender in Modern Icelandic in order to see if any of their originally assigned genders changed in the modern language. That none of the loans analyzed in this report changed their gender assignment from neuter to masculine as in West Germanic supports Steinmetz' and Trosterud's notions of Icelandic having a neuter-default gender system. These findings also support Schwink's view (2004:99), when he writes that Icelandic's gender system remains relatively unchanged from that of Old Norse.Germanic Studie

Neurotoxicity of Two Related Organophosphates on Caenorhabditis Elegans

Organophosphates are a class of toxicants that act by inhibiting the activity of acetylcholinesterase, an enzyme vital to normal neuronal activity. Dimethoate and omethoate are two organophosphates that are chemical cousins of one another. Omethoate is a metabolite, or byproduct of dimethoate decomposition, and is more toxicologically active than dimethoate. Both toxicants were applied to cultures of Caenorhabditis elegans to determine two qualities of the organophosphates: their relative toxicity and their cumulative effects. The toxicity of omethoate was found to be significantly higher than that of dimethoate. Omethoate was found to have a 144.4% more lethal toxicity than dimethoate, and was 132.3% more effective at causing flaccid paralysis. Neither compound exhibited notable cumulative effects

Neurotoxicity of Two Related Organophosphates on Caenorhabditis Elegans

Organophosphates are a class of toxicants that act by inhibiting the activity of acetylcholinesterase, an enzyme vital to normal neuronal activity. Dimethoate and omethoate are two organophosphates that are chemical cousins of one another. Omethoate is a metabolite, or byproduct of dimethoate decomposition, and is more toxicologically active than dimethoate. Both toxicants were applied to cultures of Caenorhabditis elegans to determine two qualities of the organophosphates: their relative toxicity and their cumulative effects. The toxicity of omethoate was found to be significantly higher than that of dimethoate. Omethoate was found to have a 144.4% more lethal toxicity than dimethoate, and was 132.3% more effective at causing flaccid paralysis. Neither compound exhibited notable cumulative effects

Investigating the noise residuals around the gravitational wave event GW150914

We use the Pearson cross-correlation statistic proposed by Liu and Jackson, and employed by Creswell et al., to look for statistically significant correlations between the LIGO Hanford and Livingston detectors at the time of the binary black hole merger GW150914. We compute this statistic for the calibrated strain data released by LIGO, using both the residuals provided by LIGO and using our own subtraction of a maximum-likelihood waveform that is constructed to model binary black hole mergers in general relativity. To assign a significance to the values obtained, we calculate the cross-correlation of both simulated Gaussian noise and data from the LIGO detectors at times during which no detection of gravitational waves has been claimed. We find that after subtracting the maximum likelihood waveform there are no statistically significant correlations between the residuals of the two detectors at the time of GW150914.Comment: 14 pages, 7 figures. Minor text and figure changes in final v3. Notebooks for generating the results are available at https://github.com/gwastro/gw150914_investigatio

Arbitrary precision composite pulses for NMR quantum computing

We discuss the implementation of arbitrary precision composite pulses developed using the methods of Brown et al. [Phys. Rev. A 70 (2004) 052318]. We give explicit results for pulse sequences designed to tackle both the simple case of pulse length errors and for the more complex case of off-resonance errors. The results are developed in the context of NMR quantum computation, but could be applied more widely.Comment: 16 pages elsart, no figures. In press at Journal of Magnetic resonanc

Using gravitational waves to distinguish between neutron stars and black holes in compact binary mergers

In August 2017, the first detection of a binary neutron star merger, GW170817, made it possible to study neutron stars in compact binary systems using gravitational waves. Despite being the loudest gravitational wave event detected to date (in terms of signal-to-noise ratio), it was not possible to unequivocally determine that GW170817 was caused by the merger of two neutron stars instead of two black holes from the gravitational-wave data alone. That distinction was primarily due to the accompanying electromagnetic counterpart. This raises the question: under what circumstances can gravitational-wave data alone, in the absence of an electromagnetic signal, be used to distinguish between different types of mergers? Here, we study whether a neutron star-black hole binary merger can be distinguished from a binary black hole merger using gravitational-wave data alone. We build on earlier results using chiral effective field theory to explore whether the data from LIGO and Virgo, LIGO A+, LIGO Voyager, the Einstein Telescope, or Cosmic Explorer could lead to such a distinction. The results suggest that the present LIGO-Virgo detector network will most likely be unable to distinguish between these systems even with the planned near-term upgrades. However, given an event with favorable parameters, third-generation instruments such as Cosmic Explorer will be capable of making this distinction. This result further strengthens the science case for third-generation detectors.Comment: 16 pages, 7 figures, 13 table

A contextual definition of longitudinal integrated clerkships within the UK and Ireland: a bi-national modified Delphi study

Disagreement exists within the UK and Ireland regarding how Longitudinal Integrated Clerkships should be defined, and the relevance of international definitions. In this modified, online Delphi study, we presented the UK and Ireland experts in Longitudinal Integrated Clerkships with statements drawn from international definitions, published LIC literature, and the research team's experience in this area and asked them to rate their level of agreement with these statements for inclusion in a bi-national consensus definition. We undertook three rounds of the study to try and elicit consensus, making adaptations to statement wording following rounds 1 and 2 to capture participants' qualitative free text-comments, following the third and final round, nine statements were accepted by our panel, and constitute our proposed definition of Longitudinal Integrated Clerkships within the UK and Ireland. This definitional statement corresponds with some international literature but offers important distinctions, which account for the unique context of healthcare (particularly primary care) within the UK and Ireland (for example, the lack of time-based criteria within the definition). This definition should allow UK and Irish researchers to communicate more clearly with one another regarding the benefits of LICs and longitudinal learning and offers cross-national collaborative opportunities in LIC design, delivery and evaluation