3,984 research outputs found

    Reflections on the Arts, Environment, and Culture After Ten Years of The Goose

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    To mark the tenth anniversary of The Goose, we asked prominent ecologically-minded scholars, writers, artists, and educators from across Canada to reflect on the relationship between the arts, culture, and the environment. Their comments illuminate a wide range of triumphs and tensions, from the politics and practices of environmentalist writing and art, to the connections between the environment and matters of diversity and justice, to the past and future of ALECC (Association for Literature, Environment, and Culture in Canada), to the world of a single poem

    A Link to the Past: Using Markov Chain Monte Carlo Fitting to Constrain Fundamental Parameters of High-Redshift Galaxies

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    We have a developed a new method for fitting spectral energy distributions (SEDs) to identify and constrain the physical properties of high-redshift (4 < z < 8) galaxies. Our approach uses an implementation of Bayesian based Markov Chain Monte Carlo (PiMC^2) that allows us to compare observations to arbitrarily complex models and to compute 95% credible intervals that provide robust constraints for the model parameters. The work is presented in 2 sections. In the first, we test PiMC^2 using simulated SEDs to not only confirm the recovery of the known inputs but to assess the limitations of the method and identify potential hazards of SED fitting when applied specifically to high redshift (z>4) galaxies. Our tests reveal five critical results: 1) the ability to confidently constrain metallicity, population ages, and Av all require photometric accuracy better than what is currently achievable (i.e. less than a few percent); 2) the ability to confidently constrain stellar masses (within a factor of two) can be achieved without the need for high-precision photometry; 3) the addition of IRAC photometry does not guarantee that tighter constraints of the stellar masses and ages can be defined; 4) different assumptions about the star formation history can lead to significant biases in mass and age estimates; and 5) we are able to constrain stellar age and Av of objects that are both young and relatively dust free. In the second part of the paper we apply PiMC^2 to 17 4<z<8 objects, including the GRAPES Ly alpha sample (4<z<6), supplemented by HST/WFC3 near-IR observations, and several broad band selected z>6 galaxies. Using PiMC^2, we are able to constrain the stellar mass of these objects and in some cases their stellar age and find no evidence that any of these sources formed at a redshift much larger than z_f=8, a time when the Universe was ~ 0.6 Gyr old.Comment: Submitted to ApJ (Full abstract, 47 pages, 17 figures, 7 tables

    Chlorido(4,4′,4′′-tri-tert-butyl-2,2′:6′,2′′-terpyridine)­platinum(II) chloride toluene monosolvate

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    In the title compound, [PtCl(C27H35N3)]Cl·C7H8, the PtII atom is coordinated in a pseudo-square-planar fashion by the N atoms of a 4,4′,4′′-tri-tert-butyl-2,2′:6′,2′′-terpyridine (tbtrpy) ligand and a Cl atom. The Pt—N distance of the N atom on the central pyridine is 1.941 (4) Å, while the peripheral N atoms have Pt—N distances of 2.015 (4) and 2.013 (4) Å. The Pt—Cl bond distance is 2.3070 (10) Å. The cations pack as dimers in a head-to-tail orientation with an inter­molecular Pt⋯Pt distance of 3.2774 (3) Å and Pt⋯N distances of 3.599 (4), 3.791 (4) and 4.115 (4) Å. The solvent mol­ecule is disordered and occupies two positions with a ratio of 0.553 (6):0.447 (6)

    Chlorido(4,4′,4′′-tri-tert-butyl-2,2′:6′,2′′-terpyridine)­platinum(II) tetra­fluorido­borate

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    In the title compound, [PtCl(C27H35N3)]BF4, the PtII atom is in a pseudo-square-planar coordination, which is typical of Pt–terpyridine complexes. The Pt—Cl bond distance is 2.2998 (7) Å. The Pt—N distance of the N atom on the central pyridine is 1.931 (2) Å, while the peripheral N atoms have Pt—N distances of 2.018 (2) and 2.022 (2) Å. The cations pack as dimers in a head-to-tail orientation with an inter­molecular Pt⋯Pt distance of 3.5214 (2) Å and Pt⋯N distances of 3.527 (2), 3.873 (2) and 4.532 (2) Å. In the crystal, cations and anions are linked by weak C—H⋯F hydrogen-bonding inter­actions

    A Link to the Past: Using Markov Chain Monte Carlo Fitting to Constrain Fundamental Parameters of High-Redshift Galaxies

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    We have a developed a new method for fitting spectral energy distributions (SEDs) to identify and constrain the physical properties of high-redshift (4 < z < 8) galaxies. Our approach uses an implementation of Bayesian based Markov Chain Monte Carlo (PiMC^2) that allows us to compare observations to arbitrarily complex models and to compute 95% credible intervals that provide robust constraints for the model parameters. The work is presented in 2 sections. In the first, we test PiMC^2 using simulated SEDs to not only confirm the recovery of the known inputs but to assess the limitations of the method and identify potential hazards of SED fitting when applied specifically to high redshift (z>4) galaxies. Our tests reveal five critical results: 1) the ability to confidently constrain metallicity, population ages, and Av all require photometric accuracy better than what is currently achievable (i.e. less than a few percent); 2) the ability to confidently constrain stellar masses (within a factor of two) can be achieved without the need for high-precision photometry; 3) the addition of IRAC photometry does not guarantee that tighter constraints of the stellar masses and ages can be defined; 4) different assumptions about the star formation history can lead to significant biases in mass and age estimates; and 5) we are able to constrain stellar age and Av of objects that are both young and relatively dust free. In the second part of the paper we apply PiMC^2 to 17 4<z<8 objects, including the GRAPES Ly alpha sample (4<z<6), supplemented by HST/WFC3 near-IR observations, and several broad band selected z>6 galaxies. Using PiMC^2, we are able to constrain the stellar mass of these objects and in some cases their stellar age and find no evidence that any of these sources formed at a redshift much larger than z_f=8, a time when the Universe was ~ 0.6 Gyr old.Comment: Submitted to ApJ (Full abstract, 47 pages, 17 figures, 7 tables

    Genome Sequence of Stenotrophomonas maltophilia PML168, Which Displays Baeyer-Villiger Monooxygenase Activity

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    Stenotrophomonas maltophilia PML168 was isolated from Wembury Beach on the English Coast from a rock pool following growth and selection on agar plates. Here we present the permanent draft genome sequence, which has allowed prediction of function for several genes encoding enzymes relevant to industrial biotechnology, including a novel flavoprotein monooxygenase

    Phase transitions and the internal noise structure of nonlinear Schr\"odi nger equation solitons

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    We predict phase-transitions in the quantum noise characteristics of systems described by the quantum nonlinear Schr\"odinger equation, showing them to be related to the solitonic field transition at half the fundamental soliton amplitude. These phase-transitions are robust with respect to Raman noise and scattering losses. We also describe the rich internal quantum noise structure of the solitonic fields in the vicinity of the phase-transition. For optical coherent quantum solitons, this leads to the prediction that eliminating the peak side-band noise due to the electronic nonlinearity of silica fiber by spectral filtering leads to the optimal photon-number noise reduction of a fundamental soliton.Comment: 10 pages, 5 figure

    Linking Life Skills and Norms with adolescent substance use and delinquency in South Africa

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    We examined factors targeted in two popular prevention approaches with adolescent drug use and delinquency in South Africa. We hypothesized adolescent life skills to be inversely related, and perceived norms to be directly related to later drug use and delinquency. Multiple regression and a relative weights approach were conducted for each outcome using a sample of 714 South African adolescents ages 15 to 19 years (M = 15.8 years, 57% female). Perceived norms predicted gateway drug use. Conflict resolution skills (inversely) and perceived peer acceptability (directly) predicted harder drug use and delinquency. The “culture of violence” within some South African schools may make conflict resolution skills more salient for preventing harder drug use and delinquency.Department of HE and Training approved lis
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