Dynamics and instability of false vacuum bubbles

This paper examines the classical dynamics of false vacuum regions embedded in surrounding regions of true vacuum, in the thin-wall limit. The dynamics of all generally relativistically allowed solutions -- most but not all of which have been previously studied -- are derived, enumerated, and interpreted. We comment on the relation of these solutions to possible mechanisms whereby inflating regions may be spawned from non-inflating ones. We then calculate the dynamics of first order deviations from spherical symmetry, finding that many solutions are unstable to such aspherical perturbations. The parameter space in which the perturbations on bound solutions inevitably become nonlinear is mapped. This instability has consequences for the Farhi-Guth-Guven mechanism for baby universe production via quantum tunneling.Comment: 16 PRD-style pages including 11 embedded figures; accepted by PRD. Revised version includes new solution, discussion of 'thermal activation', added reference, fixed typo

Principals\u27 leadership behaviors as perceived by teachers in at-risk middle schools.

A need for greater understanding of teachers\u27 (N= 530) perceptions of the leadership behaviors of principals in Title I middle schools (n = 13) is prevalent exists. The researcher used the Audit of Principal Effectiveness survey to collect data. The researcher also used Hierarchical Linear Modeling as the quantitative analysis. Significant teacher-level variables were teacher age, years the teacher worked for current principal, and teacher gender. Significant school-level variables were principal gender, principal teaching experience, and percentage of low-income students scoring proficient in mathematics. Principals should understand how teacher- and school-level variables affect the principals\u27 perceived leadership behaviors. This study has implications for university personnel, school district personnel, school principals, and hiring committees

European Bat Lyssavirus Type 2 RNA in Myotis daubentonii

Organ distribution of European bat lyssavirus type 2 viral RNA in its reservoir host, Myotis daubentonii (Daubenton's bat), was measured with a novel quantitative reverse transcription–polymerase chain reaction assay. High levels of genomic RNA were found in the brain and were also detectable in the tongue, bladder, and stomach

Detecting Geyser Activity with Infrasound

We monitored geyser activity in the Lower Geyser Basin (LGB) of Yellowstone National Park with dual four-element microphone arrays separated by ~ 600 m. The arrays were independently used to identify incident coherent plane wave energy, then conjoint cross beam back-azimuths from the two arrays were used to precisely locate signal sources. During a week in August 2011 we located repeating infrasound events, peaked in energy between 1 and 10 Hz, originating from at least five independent geothermal features, including the episodically erupting Great Fountain, Fountain and Kaleidoscope Geysers, as well as periodic infrasound from nearby Botryoidal and persistent sound from Firehole Spring. Although activity from nearby cone-type geysers was not detected in the infrasound band up through 50 Hz, the major fountain-type geysers (i.e., with columns greater than 10 m) could be detected at several kilometers, and two minor geysers (i.e., a few meters in eruption height) could be tracked at distances up to a few hundred meters. Detection of geyser activity was especially comprehensive at night when ambient noise was low. We conclude that infrasound monitoring of fountain-type geysers permits convenient tracking of geyser activity, episodicity, signal duration, energy content, and spectral content. These parameters enable objective statistical quantification of geyser behavior and changes over time that may be due to external forcing. Infrasonic study of geyser activity in an individual basin has great monitoring utility and can be reasonably accomplished with two or more distributed sensor arrays

A better sequence-read simulator program for metagenomics

BACKGROUND: There are many programs available for generating simulated whole-genome shotgun sequence reads. The data generated by many of these programs follow predefined models, which limits their use to the authors' original intentions. For example, many models assume that read lengths follow a uniform or normal distribution. Other programs generate models from actual sequencing data, but are limited to reads from single-genome studies. To our knowledge, there are no programs that allow a user to generate simulated data following non-parametric read-length distributions and quality profiles based on empirically-derived information from metagenomics sequencing data. RESULTS: We present BEAR (Better Emulation for Artificial Reads), a program that uses a machine-learning approach to generate reads with lengths and quality values that closely match empirically-derived distributions. BEAR can emulate reads from various sequencing platforms, including Illumina, 454, and Ion Torrent. BEAR requires minimal user input, as it automatically determines appropriate parameter settings from user-supplied data. BEAR also uses a unique method for deriving run-specific error rates, and extracts useful statistics from the metagenomic data itself, such as quality-error models. Many existing simulators are specific to a particular sequencing technology; however, BEAR is not restricted in this way. Because of its flexibility, BEAR is particularly useful for emulating the behaviour of technologies like Ion Torrent, for which no dedicated sequencing simulators are currently available. BEAR is also the first metagenomic sequencing simulator program that automates the process of generating abundances, which can be an arduous task. CONCLUSIONS: BEAR is useful for evaluating data processing tools in genomics. It has many advantages over existing comparable software, such as generating more realistic reads and being independent of sequencing technology, and has features particularly useful for metagenomics work

Clinical consequences of asbestos-related diffuse pleural thickening: A review

Asbestos-related diffuse pleural thickening (DPT), or extensive fibrosis of the visceral pleura secondary to asbestos exposure, is increasingly common due to the large number of workers previously exposed to asbestos. It may coexist with asbestos related pleural plaques but has a distinctly different pathology. The pathogenesis of this condition as distinct from pleural plaques is gradually becoming understood. Generation of reactive oxygen and nitrogen species, profibrotic cytokines and growth factors in response to asbestos is likely to play a role in the formation of a fibrinous intrapleural matrix. Benign asbestos related pleural effusions commonly antedate the development of diffuse pleural thickening. Environmental as well as occupational exposure to asbestos may also result in pleural fibrosis, particularly in geographic areas with naturally occurring asbestiform soil minerals. Pleural disorders may also occur after household exposure. High resolution computed tomography (CT) is more sensitive and specific than chest radiography for the diagnosis of diffuse pleural thickening, and several classification systems for asbestos-related disorders have been devised. Magnetic resonance imaging and fluorodeoxyglucose positron emission tomography (PET) scanning may be useful in distinguishing between DPT and malignant mesothelioma. DPT may be associated with symptoms such as dyspnoea and chest pain. It causes a restrictive defect on lung function and may rarely result in respiratory failure and death. Treatment is primarily supportive

Inversion of Ultrasonic Scattering Data to Measure Defect Size, Orientation, and Acoustic Properties

Empirical solutions via the adaptive learning network methodology have been obtained to measure characteristics of three-dimensional defects (spherical and spheroidal) from the analysis of theoretically-modeled scattered waveforms. The solutions have been successfully applied to measure defects from actually observed ultrasonic scattering data. Spherical voids and inclusions in Ti-6-4, varying in diameter from 0.02 em to 0.12 em, and varying In acoustic impedance ratio !with respect to the host alloy (Ti-6-4)] from zero for air cavities to four for tungsten-carbide inclusions, can be directly measured via: (i) The phase cepstrum - which yields an unambiguous measurement of defect diameter and is independent of its acoustic impedance ratio; (ii) Adaptive Learning Networks (ALN) - synthesized from the amplitude spectrum and which yield accurate measurements of defect diameter and the acoustic impedance ratio of the included material. The two empirical solutions. synthesized from the scattering data from an exact model for spheres, yield similar accurate results when applied to actual scattering observed from the defects. Spheroidal defects (oblate spheroids) varying in aspect ratio from 1.67 to 6, varying in volume from 20 to 310 millionths of a cubic centimeter, and varying in orientation from 0°· to 360° in azimuth and 0° to 90° in elevation, can be measured by adaptive learning networks synthesized from scattering data produced by the Born approximation as the theoretical model. Scattering data used to train the ALNs were obtained via computer simulation. As in the case of spheres, the ALNs were trained-using the synthetic waveforms--to predict the defect size and orientation. Once the empirical models were obtained, eight actual defect sizes and orientations were found via the models and these results compare well with the true values. This paper will describe the means by which the inversion of ultrasonic scattering to defect characteristics was accomplished and its NDE implications

Rapid Molecular Detection Methods for Arboviruses of Livestock of Importance to Northern Europe

Arthropod-borne viruses (arboviruses) have been responsible for some of the most explosive epidemics of emerging infectious diseases over the past decade. Their impact on both human and livestock populations has been dramatic. The early detection either through surveillance or diagnosis of virus will be a critical feature in responding and resolving the emergence of such epidemics in the future. Although some of the most important emerging arboviruses are human pathogens, this paper aims to highlight those diseases that primarily affect livestock, although many are zoonotic and some occasionally cause human mortality. This paper also highlights the molecular detection methods specific to each virus and identifies those emerging diseases for which a rapid detection methods are not yet developed