Growth and the Environment in Canada: An Empirical Analysis

Standard reduced form models are estimated for Canada to examine the relationships between real per capita GDP and four measures of environmental degradation. Of the four chosen measures of environmental degradation, only concentrations of carbon monoxide appear to decline in the long run with increases in real per capita income. The data used in the reduced form models are also tested for the presence of unit roots and for the existence of cointegration between each of the measures of environmental degradation and per capita income. Unit root tests indicate nonstationarity in logs of the measures of environmental degradation and per capita income. The Engle-Granger test and the maximum eigenvalue test suggest that per capita income and the measures of environmental degradation are not cointegrated, or that a long-term relationship between the variables does not exist. Causality tests also indicate a bi-directional causality, rather than a uni-directional causality, from income to the environment. The results suggest that Canada does not have the luxury of being able to grow out of its environmental problems. The implication is that to prevent further environmental degradation, Canada requires concerted policies and incentives to reduce pollution intensity per unit of output across sectors, to shift from more to less pollution-producing-outputs and to lower the environmental damage associated with aggregate consumption.environment, economic growth, Canada

Better safe than sorry: Risky function exploitation through safe optimization

Exploration-exploitation of functions, that is learning and optimizing a mapping between inputs and expected outputs, is ubiquitous to many real world situations. These situations sometimes require us to avoid certain outcomes at all cost, for example because they are poisonous, harmful, or otherwise dangerous. We test participants' behavior in scenarios in which they have to find the optimum of a function while at the same time avoid outputs below a certain threshold. In two experiments, we find that Safe-Optimization, a Gaussian Process-based exploration-exploitation algorithm, describes participants' behavior well and that participants seem to care firstly whether a point is safe and then try to pick the optimal point from all such safe points. This means that their trade-off between exploration and exploitation can be seen as an intelligent, approximate, and homeostasis-driven strategy.Comment: 6 pages, submitted to Cognitive Science Conferenc

An Atom Michelson Interferometer on a Chip Using a Bose-Einstein Condensate

An atom Michelson interferometer is implemented on an "atom chip." The chip uses lithographically patterned conductors and external magnetic fields to produce and guide a Bose-Einstein condensate. Splitting, reflecting, and recombining of condensate atoms are achieved by a standing-wave light field having a wave vector aligned along the atom waveguide. A differential phase shift between the two arms of the interferometer is introduced by either a magnetic-field gradient or with an initial condensate velocity. Interference contrast is still observable at 20% with atom propagation time of 10 ms

Scattering of Ultrasound (Including Rayleigh Waves) by Surface Roughness and by Single Surface Flaws. A Review of the Work Done at Paris 7 University

Since some years our team has worked on the characterization of rough surfaces from a study of the angular and frequency dependence of the backscattered intensity of ultrasonic waves. We shall discuss, in view of our experimental results, the different components of the signature of the surface profile which can be evaluated by these means: r.m.s. roughness h with a precision of the order of 1 μm in the range 6-100 μm influence of the autocorrelation distance L when present, surface periodicities with a precision which can be better than 1%. In the case of quasiperiodic surfaces, we shall present a comparison between the spectra theoretically predicted in the low-frequency approximation for various samples, and the ultrasonic spectra actually observed. Since 1977, we have also used Rayleigh waves to study surface properties and surface cracks in ceramics and metals and we shall give an introduction to the results obtained at the present time. This topic will be developed by B.R. Tittmann in a following paper

Lorentz-Violating Electrostatics and Magnetostatics

The static limit of Lorentz-violating electrodynamics in vacuum and in media is investigated. Features of the general solutions include the need for unconventional boundary conditions and the mixing of electrostatic and magnetostatic effects. Explicit solutions are provided for some simple cases. Electromagnetostatics experiments show promise for improving existing sensitivities to parity-odd coefficients for Lorentz violation in the photon sector.Comment: 9 page

Feasibility of informing syndrome-level empiric antibiotic recommendations using publicly available antibiotic resistance datasets.

Background: Antibiotics are often prescribed empirically to treat infection syndromes before causative bacteria and their susceptibility to antibiotics are identified. Guidelines on empiric antibiotic prescribing are key to effective treatment of infection syndromes, and need to be informed by likely bacterial aetiology and antibiotic resistance patterns. We aimed to create a clinically-relevant composite index of antibiotic resistance for common infection syndromes to inform recommendations at the national level. Methods: To create our index, we used open-access antimicrobial resistance (AMR) surveillance datasets, including the ECDC Surveillance Atlas, CDDEP ResistanceMap, WHO GLASS and the newly-available Pfizer ATLAS dataset. We integrated these with data on aetiology of common infection syndromes, existing empiric prescribing guidelines, and pricing and availability of antibiotics. Results:  The ATLAS dataset covered many more bacterial species (287) and antibiotics (52) than other datasets (ranges = 8-11 and 16-32 respectively), but had a similar number of samples per country per year. Using these data, we were able to make empiric prescribing recommendations for bloodstream infection, pneumonia and cellulitis/skin abscess in up to 44 countries. There was insufficient data to make national-level recommendations for the other six syndromes investigated. Results are presented in an interactive web app, where users can visualise underlying resistance proportions to first-line empiric antibiotics for infection syndromes and countries of interest. Conclusions: We found that whilst the creation of a composite resistance index for empiric antibiotic therapy was technically feasible, the ATLAS dataset in its current form can only inform on a limited number of infection syndromes. Other open-access AMR surveillance datasets are largely limited to bloodstream infection specimens and cannot directly inform treatment of other syndromes. With improving availability of international AMR data and better understanding of infection aetiology, this approach may prove useful for informing empiric prescribing decisions in settings with limited local AMR surveillance data

Toward Predicting Self-Splicing and Protein-Facilitated Splicing of Group I Introns

In the current era of massive discoveries of noncoding RNAs within genomes, being able to infer a function from a nucleotide sequence is of paramount interest. Although studies of individual group I introns have identified self-splicing and nonself-splicing examples, there is no overall understanding of the prevalence of self-splicing or the factors that determine it among the \u3e2300 group I introns sequenced to date. Here, the self-splicing activities of 12 group I introns from various organisms were assayed under six reaction conditions that had been shown previously to promote RNA catalysis for different RNAs. Besides revealing that assessing self-splicing under only one condition can be misleading, this survey emphasizes that in vitro self-splicing efficiency is correlated with the GC content of the intron (\u3e35% GC was generally conductive to self-splicing), and with the ability of the introns to form particular tertiary interactions. Addition of the Neurospora crassa CYT-18 protein activated splicing of two nonself-splicing introns, but inhibited the second step of self-splicing for two others. Together, correlations between sequence, predicted structure and splicing begin to establish rules that should facilitate our ability to predict the self-splicing activity of any group I intron from its sequence

Spitzer IRAC observations of newly-discovered planetary nebulae from the Macquarie-AAO-Strasbourg H-alpha Planetary Nebula Project

We compare H-alpha, radio continuum, and Spitzer Space Telescope (SST) images of 58 planetary nebulae (PNe) recently discovered by the Macquarie-AAO-Strasbo- urg H-alpha PN Project (MASH) of the SuperCOSMOS H-alpha Survey. Using InfraRed Array Camera (IRAC) data we define the IR colors of PNe and demonstrate good isolation between these colors and those of many other types of astronomical object. The only substantive contamination of PNe in the color-color plane we illustrate is due to YSOs. However, this ambiguity is readily resolved by the unique optical characteristics of PNe and their environs. We also examine the relationships between optical and MIR morphologies from 3.6 to 8.0um and explore the ratio of mid-infrared (MIR) to radio nebular fluxes, which is a valuable discriminant between thermal and nonthermal emission. MASH emphasizes late evolutionary stages of PNe compared with previous catalogs, enabling study of the changes in MIR and radio flux that attend the aging process. Spatially integrated MIR energy distributions were constructed for all MASH PNe observed by the GLIMPSE Legacy Project, using the H-alpha morphologies to establish the dimensions for the calculations of the Midcourse Space Experiment (MSX), IRAC, and radio continuum (from the Molonglo Observatory Synthesis Telescope and the Very Large Array) flux densities. The ratio of IRAC 8.0-um to MSX 8.3-um flux densities provides a measure of the absolute diffuse calibration of IRAC at 8.0 um. We independently confirm the aperture correction factor to be applied to IRAC at 8.0um to align it with the diffuse calibration of MSX. The result agrees with the recommendations of the Spitzer Science Center and with results from a parallel study of HII regions. These PNe probe the diffuse calibration of IRAC on a spatial scale of 9-77 arcsec.Comment: 48 pages, LaTeX (aastex), incl. 18 PostScript (eps) figures and 3 tables. Accepted by Astrophysical Journa