1,558 research outputs found

    Report of the Annual Banquet

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    Mary I. Lyman wrote and presented verses of the events of the Annual New Year\u27s Banquet at the January 21, 1890 Phi Sigma meeting.https://digitalcommons.colum.edu/phisigma_letters/1003/thumbnail.jp

    The History of Phi Sigma Camp at Twin Lakes, From July 1st to July 15th, 1890

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    At the July 22, 1890 meeting of the Chicago-based literary society, Phi Sigma, Mary I. Lyman presented her paper on the group\u27s camping trip to Twin Lakes, Wisconsin.https://digitalcommons.colum.edu/pscamping_docs/1000/thumbnail.jp

    Doppler Frequency Analysis by a Storage Tube and Filter Bank Analyzer. Theory of the Sinufly Computer.

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    Control Systems Laboratory changed its name to Coordinated Science LaboratoryContract DA-36-039-SC-5669

    Quality of survival: a new concept framework to assess the quality of prolonged life in cancer

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    Background: Improved cancer care means that more patients are surviving longer, but there is a need to examine how well patients survive. We conducted an exploratory analysis of a new conceptual framework termed ‘quality of survival’ (QoS) that delineates the quality of patients’ experience. Methods: This project included an electronic database search to investigate the survivorship landscape and to create a visual QoS map and semi-structured interviews with patients (n = 35), clinicians (n = 40), and payers (n = 7) to support the QoS map. QoS was discussed in the context of two tumor types, metastatic non-small cell lung cancer and metastatic melanoma. Results: Despite increased long-term survival, no specific definition of QoS exists. Patients reported many impacts that affect QoS, clinicians viewed QoS as relevant to treatment decisions, and payers felt it could help communicate different aspects relevant to the patient. Four interconnected QoS dimensions were developed (quality of life, survival, side effects, and economic impact), which vary in importance along the care continuum. Conclusion: QoS is a patient-centric concept that could help decision-making and patient communication. The QoS map could provide a framework to monitor patient experience and help patients frame what treatment attribute is most important to them at any point in the cancer continuum

    An infinite family of superintegrable systems from higher order ladder operators and supersymmetry

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    We will discuss how we can obtain new quantum superintegrable Hamiltonians allowing the separation of variables in Cartesian coordinates with higher order integrals of motion from ladder operators. We will discuss also how higher order supersymmetric quantum mechanics can be used to obtain systems with higher order ladder operators and their polynomial Heisenberg algebra. We will present a new family of superintegrable systems involving the fifth Painleve transcendent which possess fourth order ladder operators constructed from second order supersymmetric quantum mechanics. We present the polynomial algebra of this family of superintegrable systems.Comment: 8 pages, presented at ICGTMP 28, accepted for j.conf.serie

    SUSY approach to Pauli Hamiltonians with an axial symmetry

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    A two-dimensional Pauli Hamiltonian describing the interaction of a neutral spin-1/2 particle with a magnetic field having axial and second order symmetries, is considered. After separation of variables, the one-dimensional matrix Hamiltonian is analyzed from the point of view of supersymmetric quantum mechanics. Attention is paid to the discrete symmetries of the Hamiltonian and also to the Hamiltonian hierarchies generated by intertwining operators. The spectrum is studied by means of the associated matrix shape-invariance. The relation between the intertwining operators and the second order symmetries is established and the full set of ladder operators that complete the dynamical algebra is constructed.Comment: 18 pages, 3 figure

    Superintegrability and higher order polynomial algebras II

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    In an earlier article, we presented a method to obtain integrals of motion and polynomial algebras for a class of two-dimensional superintegrable systems from creation and annihilation operators. We discuss the general case and present its polynomial algebra. We will show how this polynomial algebra can be directly realized as a deformed oscillator algebra. This particular algebraic structure allows to find the unitary representations and the corresponding energy spectrum. We apply this construction to a family of caged anisotropic oscillators. The method can be used to generate new superintegrable systems with higher order integrals. We obtain new superintegrable systems involving the fourth Painleve transcendent and present their integrals of motion and polynomial algebras.Comment: 11 page

    The delay time distribution of supernovae from integral-field spectroscopy of nearby galaxies

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    Constraining the delay-time distribution (DTD) of different supernova (SN) types can shed light on the timescales of galaxy chemical enrichment and feedback processes affecting galaxy dynamics, and SN progenitor properties. Here, we present an approach to recover SN DTDs based on integral field spectroscopy (IFS) of their host galaxies. Using a statistical analysis of a sample of 116 supernovae in 102 galaxies, we evaluate different DTD models for SN types Ia (73), II (28) and Ib/c (15). We find the best SN Ia DTD fit to be a power law with an exponent α=−1.1±0.3\alpha = -1.1\pm 0.3 (50\% confidence interval), and a time delay (between star formation and the first SNe) Δ=50−35+100 Myr\Delta = 50^{+100}_{-35}~Myr (50\% C.I.). For core collapse (CC) SNe, both of the Zapartas et al. (2017) DTD models for single and binary stellar evolution are consistent with our results. For SNe II and Ib/c, we find a correlation with a Gaussian DTD model with σ=82−23+129 Myr\sigma = 82^{+129}_{-23}~Myr and σ=56−9+141 Myr\sigma = 56^{+141}_{-9}~Myr (50\% C.I.) respectively. This analysis demonstrates that integral field spectroscopy opens a new way of studying SN DTD models in the local universe

    The effect of discrete vs. continuous-valued ratings on reputation and ranking systems

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    When users rate objects, a sophisticated algorithm that takes into account ability or reputation may produce a fairer or more accurate aggregation of ratings than the straightforward arithmetic average. Recently a number of authors have proposed different co-determination algorithms where estimates of user and object reputation are refined iteratively together, permitting accurate measures of both to be derived directly from the rating data. However, simulations demonstrating these methods' efficacy assumed a continuum of rating values, consistent with typical physical modelling practice, whereas in most actual rating systems only a limited range of discrete values (such as a 5-star system) is employed. We perform a comparative test of several co-determination algorithms with different scales of discrete ratings and show that this seemingly minor modification in fact has a significant impact on algorithms' performance. Paradoxically, where rating resolution is low, increased noise in users' ratings may even improve the overall performance of the system.Comment: 6 pages, 2 figure

    The shape of oxygen abundance profiles explored with MUSE: evidence for widespread deviations from single gradients

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    We characterised the oxygen abundance radial distribution of a sample of 102 spiral galaxies observed with VLT/MUSE using the O3N2 calibrator. The high spatial resolution of the data allowed us to detect 14345 H ii regions with the same image quality as with photometric data, avoiding any dilution effect. We developed a new methodology to automatically fit the abundance radial profiles, finding that 55 galaxies of the sample exhibit a single negative gradient. The remaining 47 galaxies also display, as well as this negative trend, either an inner drop in the abundances (21), an outer flattening (10), or both (16), which suggests that these features are a common property of disc galaxies. The presence and depth of the inner drop depends on the stellar mass of the galaxies with the most massive systems presenting the deepest abundance drops, while there is no such dependence in the case of the outer flattening. We find that the inner drop appears always around 0.5 r, while the position of the outer flattening varies over a wide range of galactocentric distances. Regarding the main negative gradient, we find a characteristic slope in the sample of α =-0.10 ± 0.03 dex /r. This slope is independent of the presence of bars and the density of the environment. However, when inner drops or outer flattenings are detected, slightly steeper gradients are observed. This suggests that radial motions might play an important role in shaping the abundance profiles. We define a new normalisation scale (>the abundance scale length>, r) for the radial profiles based on the characteristic abundance gradient, with which all the galaxies show a similar position for the inner drop (~0.5 r) and the outer flattening (~1.5 r). Finally, we find no significant dependence of the dispersion around the negative gradient with any property of the galaxies, with values compatible with the uncertainties associated with the derivation of the abundances.© ESO, 2018.This study is based on observations made with ESO Telescopes at the Paranal Observatory (programmes 60.A-9329(A), 095.D-0172(A), 95.D-0091(A), 95.D-0091(B), 096.D-0263(A), 96.D-0296(A), 97.D-0408(A) and 98.D-0115(A)) and has also made use of the services of the ESO Science Archive Facility (programmes 60.A-9319(A), 60.A-9100(B), 60.A-9329(A), 60.A-9339(A), 60.A-9301(A), 196.B-0578(A) and 094.B-0733(B)). We would like to thank the anonymous referee for comments which helped to improve the content of the paper. We acknowledge financial support from the Spanish Ministerio de Economia y Competitividad (MINECO) via grants AYA2012-31935, and from the >Junta de Andalucia> local government through the FQM-108 project. We also acknowledge support to the ConaCyt funding programme 180125 and DGAPA IA100815. L.G. is supported in part by the US National Science Foundation under Grant AST-1311862. T.K. acknowledges support through the Sofja Kovalevskaja Award to P. Schady from the Alexander von Humboldt Foundation of Germany. We acknowledge the usage of the HyperLeda database (http://leda.univ-lyon1.fr).This research also makes use of python (http://www.python.org),of Matplotlib (Hunter 2007), a suite of open-source python modules that provides a framework for creating scientific plots, and Astropy, a community-developed core Python package for Astronomy (Astropy Collaboration et al. 2013).Peer reviewe
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