12,161 research outputs found

    Transform fault earthquakes in the North Atlantic: Source mechanisms and depth of faulting

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    The centroid depths and source mechanisms of 12 large earthquakes on transform faults of the northern Mid-Atlantic Ridge were determined from an inversion of long-period body waveforms. The earthquakes occurred on the Gibbs, Oceanographer, Hayes, Kane, 15 deg 20 min, and Vema transforms. The depth extent of faulting during each earthquake was estimated from the centroid depth and the fault width. The source mechanisms for all events in this study display the strike slip motion expected for transform fault earthquakes; slip vector azimuths agree to 2 to 3 deg of the local strike of the zone of active faulting. The only anomalies in mechanism were for two earthquakes near the western end of the Vema transform which occurred on significantly nonvertical fault planes. Secondary faulting, occurring either precursory to or near the end of the main episode of strike-slip rupture, was observed for 5 of the 12 earthquakes. For three events the secondary faulting was characterized by reverse motion on fault planes striking oblique to the trend of the transform. In all three cases, the site of secondary reverse faulting is near a compression jog in the current trace of the active transform fault zone. No evidence was found to support the conclusions of Engeln, Wiens, and Stein that oceanic transform faults in general are either hotter than expected from current thermal models or weaker than normal oceanic lithosphere

    3-Oxabicyclo[3,2,0]hepta-1,4-diene

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    3-Oxabicyclo[3,2,0]hepta-1,4-diene (3) has been synthesized by partial hydrogenation of 3-oxabicyclo-[3,2,0]hepta-1,4,6-triene (2)

    Supersymmetric Quantum Mechanics for String-Bits

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    We develop possible versions of supersymmetric single particle quantum mechanics, with application to superstring-bit models in view. We focus principally on space dimensions d=1,2,4,8d=1,2,4,8, the transverse dimensionalities of superstring in 3,4,6,103,4,6,10 space-time dimensions. These are the cases for which ``classical'' superstring makes sense, and also the values of dd for which Hooke's force law is compatible with the simplest superparticle dynamics. The basic question we address is: When is it possible to replace such harmonic force laws with more general ones, including forces which vanish at large distances? This is an important question because forces between string-bits that do not fall off with distance will almost certainly destroy cluster decomposition. We show that the answer is affirmative for d=1,2d=1,2, negative for d=8d=8, and so far inconclusive for d=4d=4.Comment: 17 pages, Late

    Universality and Clustering in 1+1 Dimensional Superstring-Bit Models

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    We construct a 1+1 dimensional superstring-bit model for D=3 Type IIB superstring. This low dimension model escapes the problems encountered in higher dimension models: (1) It possesses full Galilean supersymmetry; (2) For noninteracting polymers of bits, the exactly soluble linear superpotential describing bit interactions is in a large universality class of superpotentials which includes ones bounded at spatial infinity; (3) The latter are used to construct a superstring-bit model with the clustering properties needed to define an SS-matrix for closed polymers of superstring-bits.Comment: 11 pages, Latex documen

    Journey Into Shame: Implications for Justice Pedagogies

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    Being formed for justice can be a painful experience. Sometimes that pain takes the form of shame and contributes to the formation and exercise of conscience. But shame in other forms can be opposed to human flourishing and social justice. Psychologist James Fowler provides a spectrum of two forms of healthy shame and four forms of unhealthy shame, to which the author adds four other varieties, strategic shame and spiritual shame, at one end of the spectrum, and murderous shame and genocidal shame, at the other. Various experiences of shame are dramatically illustrated in Black Like Me, John Howard Griffin’s classic narrative of racism in the Deep South. It is crucial for social justice educators to be able to discern among these forms of shame in their own experience and when reported by students, so that healthy forms can be sympathetically honored and unhealthy forms critically examined

    New Crew Nights: The Impact of a Nurse Leader Led Mentorship Series on Perceived Competency in the Novice Nurse

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    Abstract Background and Purpose: Nursing leaders across the United States are seeking to recruit and retain new graduate nurses as a national nursing shortage widens at an alarming pace. Healthcare systems are tasked to strengthen the skill set of novice nurses as they seek to meet the care needs of acutely ill patients and rebuild a skilled workforce for future years. This study evaluated the impact of a four-part mentorship series for novice nurses on perceived strengths in competency, communication, wellbeing, and teamwork. Methods: In this quality improvement project with pre-intervention/post-intervention assessment, a sample (n=14) of medical surgical nurses with less than one year of nursing experience participated in a survey to evaluate the effectiveness of a nurse leader led mentorship series on four subdomains: clinical competency, communication, wellbeing, and teamwork. Results: The four-part mentorship series titled “New Crew Nights” resulted in increased perceived strengths in three domains of skills: clinical competency (p=.002), communication (p= .046), and wellbeing (p= .010). The teamwork domain mean score improved (4.2 to 4.6) but did not show statistical significance (p= .152). Discussion: Targeted mentorship sessions on critical skills needed to succeed in the nursing career had an impact on novice nurses. Participants in the program learned valuable tools to communicate in critical situations, give feedback to peers and leaders, trust their team, and care for themselves. Conclusion: Nurse leaders can impact the perceived strength of novice nurses in navigating a challenging healthcare environment through mentorship. Effective mentorship can improve sense of team and self in novice nurses while also building clinical skills at the bedside

    Instanton operators in five-dimensional gauge theories

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    This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are creditedN.L. is supported in part by STFC grant ST/J002798/1. C.P. is a Royal Society Research Fellow.N.L. is supported in part by STFC grant ST/J002798/1. C.P. is a Royal Society Research Fellow.N.L. is supported in part by STFC grant ST/J002798/1. OPen Aceess funded by SCOAP

    Slow Dynamics in Glasses

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    Minimalist theories of complex systems are broadly of two kinds: mean-field and axiomatic. So far all theories of complex properties absent from simple systems and intrinsic to glasses are axiomatic. Stretched Exponential Relaxation (SER) is the prototypical complex temporal property of glasses, discovered by Kohlrausch 150 years ago, and now observed almost universally in microscopically homogeneous, complex non-equilibrium materials, including luminescent electronic (Coulomb) glasses. Critical comparison of alternative axiomatic theories with both numerical simulations and experiments strongly favors dynamical trap models over static percolative or energy landscape models. PACS: 61.20.Lc; 67.40.F

    Disk-Like Structure in the Semi-Regular Pulsating Star, X Her

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    The author reports a result of an interferometric observation of the semiragular pulsating star with an unusual narrow molecular line profile, X Her, in the CO J=1-0 line with the Berkeley-Illinois-Maryland array. In the CO spectrum, a double-component profile (including narrow and broad components) is seen as reported by previous observations. The narrow component consists of two spiky peaks. The spatial structure of the board component shows bipolar shape, and that of the narrow component shows an elliptical/spherical shape. The two peaks in the narrow component show a systematic difference in the integrated intensity map. The kinematical and geometrical properties of the narrow component are reminiscent of a Keplerian rotating disk with the central mass of 0.9 M_sun, though an interpretation by an expansion disk seems to be more natural. A secondary bipolar flow instead of the disk cannot be fully excluded as an interpretation of the narrow line.Comment: 12 pages, 4 figues, accepted for publication in Ap

    Generalized Paraxial Ray Trace Procedure Derived from Geodesic Deviation

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    Paraxial ray tracing procedures have become widely accepted techniques for acoustic models in seismology and underwater acoustics. To date a generic form of these procedures including fluid motion and time dependence has not appeared in the literature. A detailed investigation of the characteristic curves of the equations of hydrodynamics allows for an immediate generalization of the procedure to be extracted from the equation form geodesic deviation. The general paraxial ray trace equations serve as an ideal supplement to ordinary ray tracing in predicting the deformation of acoustic beams in random environments. The general procedure is derived in terms of affine parameterization and in a coordinate time parameterization ideal for application to physical acoustic ray propagation. The formalism is applied to layered media, where the deviation equation reduces to a second order differential equation for a single field with a general solution in terms of a depth integral along the ray path. Some features are illustrated through special cases which lead to exact solutions in terms of either ordinary or special functions.Comment: Original; 40 pages (double spaced), 1 figure Replaced version; 36 pages single spaced, 7 figures. Expanded content; Complete derivation of the equations from the equations of hydrodynamics, introduction of an auxiliary basis for three dimensional wave-front modeling. Typos in text and equations correcte
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