7,908 research outputs found

    MARVELS-1b: A Short-period, Brown Dwarf Desert Candidate from the SDSS-III Marvels Planet Search

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    We present a new short-period brown dwarf (BD) candidate around the star TYC 1240-00945-1. This candidate was discovered in the first year of the Multi-object APO Radial Velocity Exoplanets Large-area Survey (MARVELS), which is part of the Sloan Digital Sky Survey (SDSS) III, and we designate the BD as MARVELS-1b. MARVELS uses the technique of dispersed fixed-delay interferometery to simultaneously obtain radial velocity (RV) measurements for 60 objects per field using a single, custom-built instrument that is fiber fed from the SDSS 2.5 m telescope. From our 20 RV measurements spread over a ~370 day time baseline, we derive a Keplerian orbital fit with semi-amplitude K = 2.533 ± 0.025 km s^(–1), period P = 5.8953 ± 0.0004 days, and eccentricity consistent with circular. Independent follow-up RV data confirm the orbit. Adopting a mass of 1.37 ± 0.11 M_☉ for the slightly evolved F9 host star, we infer that the companion has a minimum mass of 28.0 ± 1.5 M_(Jup), a semimajor axis 0.071 ± 0.002 AU assuming an edge-on orbit, and is probably tidally synchronized. We find no evidence for coherent intrinsic variability of the host star at the period of the companion at levels greater than a few millimagnitudes. The companion has an a priori transit probability of ~14%. Although we find no evidence for transits, we cannot definitively rule them out for companion radii ≲ R_(Jup)

    Accurate Microwave Control and Real-Time Diagnostics of Neutral Atom Qubits

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    We demonstrate accurate single-qubit control in an ensemble of atomic qubits trapped in an optical lattice. The qubits are driven with microwave radiation, and their dynamics tracked by optical probe polarimetry. Real-time diagnostics is crucial to minimize systematic errors and optimize the performance of single-qubit gates, leading to fidelities of 0.99 for single-qubit pi rotations. We show that increased robustness to large, deliberately introduced errors can be achieved through the use of composite rotations. However, during normal operation the combination of very small intrinsic errors and additional decoherence during the longer pulse sequences precludes any significant performance gain in our current experiment.Comment: 9 pages, 7 figure

    Structural and functional analysis of critical amino acids in TMVI of the NHE1 isoform of the Na+/H+ exchanger

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    AbstractThe mammalian Na+/H+ exchanger isoform 1 (NHE1) resides on the plasma membrane and exchanges one intracellular H+ for one extracellular Na+. It maintains intracellular pH and regulates cell volume, and cell functions including growth and cell differentiation. Previous structural and functional studies on TMVI revealed several amino acids that are potentially pore lining. We examined these and other critical residues by site-directed mutagenesis substituting Asn227→Ala, Asp, Arg; Ile233→Ala; Leu243→Ala; Glu247→Asp, Gln; Glu248→Asp, Gln. Mutant NHE1 proteins were characterized in AP-1 cells, which do not express endogenous NHE1. All the TMVI critical amino acids were highly sensitive to substitution and changes often lead to a dysfunctional protein. Mutations of Asn227→Ala, Asp, Arg; Ile233→Ala; Leu243→Ala; Glu247→Asp; Glu248→Gln yielded significant reduction in NHE1 activity. Mutants of Asn227 demonstrated defects in protein expression, targeting and activity. Substituting Asn227→Arg and Ile233→Ala decreased the surface localization and expression of NHE1 respectively. The pore lining amino acids Ile233 and Leu243 were both essential for activity. Glu247 was not essential, but the size of the residue at this location was important while the charge on residue Glu248 was more critical to NHE1 function. Limited trypsin digestion on Leu243→Ala and Glu248→Gln revealed that they had increased susceptibility to proteolytic attack, indicating an alteration in protein conformation. Modeling of TMVI with TMXI suggests that these TM segments form part of the critical fold of NHE1 with Ile233 and Leu465 of TMXI forming a critical part of the extracellular facing ion conductance pathway

    Intracranial fusarium fungal abscess in an immunocompetent patient: case report and review of the literature.

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    Introduction Fusarium spp is an omnipresent fungal species that may lead to fatal infections in immunocompromised populations. Spontaneous intracranial infection by Fusarium spp in immunocompetent individuals is exceedingly rare. Case Report An immunocompetent 33-year-old Hispanic woman presented with persistent headaches and was found to have a contrast-enhancing mass in the left petrous apex and prepontine cistern. She underwent a subsequent craniotomy for biopsy and partial resection that revealed a Fusarium abscess. She had a left transient partial oculomotor palsy following the operation that resolved over the next few weeks. She was treated with long-term intravenous antifungal therapy and remained at her neurologic baseline 18 months following the intervention. Discussion To our knowledge, this is the first reported case of Fusarium spp brain abscess in an immunocompetent patient. Treatment options include surgical intervention and various antifungal medications. Conclusion This case demonstrates the rare potential of intracranial Fusarium infection in the immunocompetent host, as well as its successful treatment with surgical aspiration and antifungal therapy

    The Master\u27s Teachings Are Not Far: \u3cem\u3eThe Analects\u3c/em\u3e of Confucius and Its Modern Relevance

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    About the Authors Katherine E. Brigman is a Chemistry major at Armstrong and has earned the distinction of Dean’s List numerous times. She is a member of the National Society of Leadership and Success. During her studies, Katie found that she enjoyed learning about other cultures and various aspects of history, so she decided to obtain a minor in History, which she finds to be an exciting compliment to the scientific world. Brian Lee is a junior History major at Armstrong. He enjoys studying Mediterranean empires of Antiquity and mid-20th Century America. He has plans to enter the graduate program after completing his undergraduate degree. Juan Rojelio is a history major and will graduate in 2019

    Variability in antifungal and antiviral use in hospitalized children

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    We analyzed antifungal and antiviral prescribing among high-risk children across freestanding children’s hospitals. Antifungal and antiviral days of therapy varied across hospitals. Benchmarking antifungal and antiviral use and developing antimicrobial stewardship strategies to optimize use of these high cost agents is needed.Infect Control Hosp Epidemiol2017;38:743–746</jats:p

    A systematic approach to station-keeping of constellations of satellites

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1998.Includes bibliographical references (leaves 154-157).by Brian Kantsiper.Ph.D
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