1,442 research outputs found

    Disrupters:Three Women of Color Tell Their Stories

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    This essay is an amplified version of the presentation we made at the 7th Biennial Seneca Falls Dialogues. Our aim is to story back into the world our first experiences and motivations for investing in suffrage and democratic activism. We are three American professors of disciplines in the humanities, who for decades have taught and lived across the United States and have traveled the world. Yuko Kurahashi’s essay tells the story of how Raichō Hiratsuka and Fusae Ichikawa, Japanese activists in their suffrage and peace movements, helped shape her personal and professional life. Denise Harrison talks about the first wave of Black suffragists, the precursors of today’s powerful black women activists who inspire her. Dulce María discusses how Latina writers and activists modeled personal political power and activism and helped her define her hybrid identity. By presenting our stories, we want to highlight issues that most women of color address: We hope that this essay fosters deep thinking about how each of us can harness and multiply the power of our life circumstances to engage in activist work for social justice. We want to speak our truths in the hope that other people, including young women of color, begin to examine how they can use their own stories and identities to help empower the disenfranchised and impoverished, and thereby to question the past, disrupt the present, and contribute to building a more equitable future

    Magnetic Ground State of Pr0.89_{0.89}LaCe0.11_{0.11}CuO4+αδ_{4+\alpha-\delta} with Varied Oxygen Depletion Probed by Muon Spin Relaxation

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    The magnetic ground state of an electron-doped cuprate superconductor Pr1x_{1-x}LaCex_xCuO4+αδ_{4+\alpha-\delta} (x=0.11,α0.04x=0.11, \alpha\simeq0.04) has been studied by means of muon spin rotation/relaxation (\msr) over a wide variety of oxygen depletion, 0.03δ0.120.03\le\delta\le0.12. Appearance of weak random magnetism over entire crystal volume has been revealed by a slow exponential relaxation. The absence of δ\delta-dependence for the random magnetism and the multiplet pattern of muon Knight shift at higher fields strongly suggest that the random moments are associated with excited Pr3+^{3+} ions under crystal electric field.Comment: 6 pages, 4 figures, submitted to J. Phys. Soc. Jp

    Oceanic Ambient Noise as a Background to Acoustic Neutrino Detection

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    Ambient noise measured in the deep ocean is studied in the context of a search for signals from ultra-high energy cosmic ray neutrinos. The spectral shape of the noise at the relevant high frequencies is found to be very stable for an extensive data set collected over several months from 49 hydrophones mounted near the bottom of the ocean at ~1600 m depth. The slopes of the ambient noise spectra above 15 kHz are found to roll-off faster than the -6 dB/octave seen in Knudsen spectra. A model attributing the source to an uniform distribution of surface noise that includes frequency-dependent absorption at large depth is found to fit the data well up to 25 kHz. This depth dependent model should therefore be used in analysis methods of acoustic neutrino pulse detection that require the expected noise spectra.Comment: Minor changes. Submitted to PRD. 5 pages, 7 figure

    #BlackLivesMatter: Intersectionality, Violence, and Socially Transformative Art

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    This paper is designed to elicit dialogue on the impact of the #Blacklivesmatter (BLM) movement and be a call to action in the wake of murder and sustained oppression of the Black body in America. The paper focuses on the intersectionality of the BLM movement using art, “racial” analysis, creative pedagogy, and the theatre of the oppressed. Included is a monologue of a mother whose child has been murdered by a “peace officer” that leads the audience on an emotional journey. In addition, sobering statistics of documented murders of Black transgender women are presented, as are the health effects of discrimination. The language of oppression and its use in the media are explored, as is a discussion of socially transformative art. Finally, recommendations are made to continue to use art and theatre as tools to raise awareness of injustice and to promote social resistance

    Advances in single crystal growth and annealing treatment of electron-doped HTSC

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    High quality electron-doped HTSC single crystals of Pr2xCexCuO4+δ\rm Pr_{2-x}Ce_{x}CuO_{4+\delta} and Nd2xCexCuO4+δ\rm Nd_{2-x}Ce_{x}CuO_{4+\delta} have been successfully grown by the container-free traveling solvent floating zone technique. The optimally doped Pr2xCexCuO4+δ\rm Pr_{2-x}Ce_{x}CuO_{4+\delta} and Nd2xCexCuO4+δ\rm Nd_{2-x}Ce_{x}CuO_{4+\delta} crystals have transition temperatures TcT_{\rm c} of 2525\,K and 23.523.5\,K, respectively, with a transition width of less than 11\,K. We found a strong dependence of the optimal growth parameters on the Ce content xx. We discuss the optimization of the post-growth annealing treatment of the samples, the doping extension of the superconducting dome for both compounds as well as the role of excess oxygen. The absolute oxygen content of the as-grown crystals is determined from thermogravimetric experiments and is found to be 4.0\ge 4.0. This oxygen surplus is nearly completely removed by a post-growth annealing treatment. The reduction process is reversible as demonstrated by magnetization measurements. In as-grown samples the excess oxygen resides on the apical site O(3). This apical oxygen has nearly no doping effect, but rather influences the evolution of superconductivity by inducing additional disorder in the CuO2_{2} layers. The very high crystal quality of Nd2xCexCuO4+δ\rm Nd_{2-x}Ce_{x}CuO_{4+\delta} is particularly manifest in magnetic quantum oscillations observed on several samples at different doping levels. They provide a unique opportunity of studying the Fermi surface and its dependence on the carrier concentration in the bulk of the crystals.Comment: 19 pages, 7 figures, submitted to Eur. Phys. J.

    Femtosecond X-ray emission study of the spin cross-over dynamics in haem proteins

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    In haemoglobin (consisting of four globular myoglobin-like subunits), the change from the low-spin (LS) hexacoordinated haem to the high spin (HS) pentacoordinated domed form upon ligand detachment and the reverse process upon ligand binding, represent the transition states that ultimately drive the respiratory function. Visible-ultraviolet light has long been used to mimic the ligand release from the haem by photodissociation, while its recombination was monitored using time-resolved infrared to ultraviolet spectroscopic tools. However, these are neither element- nor spin-sensitive. Here we investigate the transition state in the case of Myoglobin-NO (MbNO) using femtosecond Fe Kalpha and Kbeta non-resonant X-ray emission spectroscopy (XES) at an X-ray free-electron laser upon photolysis of the Fe-NO bond. We find that the photoinduced change from the LS (S = 1/2) MbNO to the HS (S = 2) deoxy-myoglobin (deoxyMb) haem occurs in ca. 800 fs, and that it proceeds via an intermediate (S = 1) spin state. The XES observables also show that upon NO recombination to deoxyMb, the return to the planar MbNO ground state is an electronic relaxation from HS to LS taking place in ca. 30 ps. Thus, the entire ligand dissociation-recombination cycle in MbNO is a spin cross-over followed by a reverse spin cross-over process

    Characterization of preplasma produced by an ultrahigh intensity laser system

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    Copyright 2004 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Physics of Plasmas, 11(8), 3721-3725, 2004 and may be found at http://dx.doi.org/10.1063/1.176077
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