2,024 research outputs found

    Planetary rover technology development requirements

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    Planetary surface (including lunar) mobility and sampling capability is required to support proposed future National Aeronautics and Space Administration (NASA) solar system exploration missions. The NASA Office of Aeronautics and Space Technology (OAST) is addressing some of these technology needs in its base research and development program, the Civil Space Technology Initiative (CSTI) and a new technology initiative entitled Pathfinder. The Pathfinder Planetary Rover (PPR) and Sample Acquisition, Analysis and Preservation (SAAP) programs will develop and validate the technologies needed to enable both robotic and piloted rovers on various planetary surfaces. The technology requirements for a planetary roving vehicle and the development plans of the PPR and SAAP programs are discussed

    2,9-Dimethyl-7-phenyl-N-(4-methyl­phen­yl)dibenzo[b,h][1,6]naphthyridin-6-amine

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    The title compound, C31H25N3, was synthesized from 6,4′,4′′-trimethyl-2,4-bis­(N-phenyl­amino)­quinoline and is the first structural example containing a phenyl and phenyl­amino fragment attached to a fused dibenzo[1,6]naphthyridine moiety. The fused tetra­cyclic ring system is essentially planar [r.m.s. deviation = 0.08 (3) Å]. The phenyl ring and the phenyl­amino group are inclined by 82.68 (6) and 35.31 (5)°, respectively, to the mean plane of the fused tetra­cyclic ring system. A weak intra­molecular N—H⋯π(arene) inter­action may in part influence the conformation of the mol­ecule. In the crystal, mol­ecules are linked by weak inter­molecular C—H⋯N hydrogen bonds into centrosymmetric dimers. Additional stabilization is provided by weak C—H⋯π and π–π stacking inter­actions [centroid–centroid distances = 3.834 (2) and 3.898 (1) Å]

    7-(2-Chloro­phen­yl)-2,6,9-trimethyl­dibenzo[b,h][1,6]naphthyridine

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    In the title compound, C25H19ClN2, the dibenzo[b,h][1,6]naphthyridine system is planar to within 0.16 (2) Å, and the chloro­phenyl ring is inclined to it by 82.53 (7)°. In the crystal, mol­ecules are linked by C—H⋯N hydrogen bonds, forming chains propagating in [100]. There are also a number of weak π–π stacking inter­actions present [centroid–centroid distances = 3.8531 (1) and 3.7631 (1) Å]

    Does the 1/f frequency-scaling of brain signals reflect self-organized critical states?

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    Many complex systems display self-organized critical states characterized by 1/f frequency scaling of power spectra. Global variables such as the electroencephalogram, scale as 1/f, which could be the sign of self-organized critical states in neuronal activity. By analyzing simultaneous recordings of global and neuronal activities, we confirm the 1/f scaling of global variables for selected frequency bands, but show that neuronal activity is not consistent with critical states. We propose a model of 1/f scaling which does not rely on critical states, and which is testable experimentally.Comment: 3 figures, 6 page

    Perceptions of the Impact of Positive Action in EU and non-EU Countries

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    yesAbstract: Around the world, inequalities exist around boundaries of race, social class, gender, disability, religious beliefs and sexual orientation, often resulting from past and current discriminatory practices. Governments have taken certain measures, including enacting policies such as positive action, to remedy such discrimination. This paper provides a comparative analysis of perceptions of the impact of positive action in seven EU and three non-EU countries. The study adopted participatory methods including consensus workshops, interviews and policy analysis to obtain data from designers of positive action. Findings are discussed, conclusions drawn and wide-ranging recommendations are made at the EC, individual countries and organisational levels

    Quantitative Analysis of Dynamic Protein Interactions during Transcription Reveals a Role for Casein Kinase II in Polymerase-associated Factor (PAF) Complex Phosphorylation and Regulation of Histone H2B Monoubiquitylation

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    Using affinity purification MS approaches, we have identified a novel role for casein kinase II (CKII) in the modification of the polymerase associated factor complex (PAF-C). Our data indicate that the facilitates chromatin transcription complex (FACT) interacts with CKII and may facilitate PAF complex phosphorylation. Posttranslational modification analysis of affinity-isolated PAF-C shows extensive CKII phosphorylation of all five subunits of PAF-C, although CKII subunits were not detected as interacting partners. Consistent with this, recombinant CKII or FACT-associated CKII isolated from cells can phosphorylate PAF-C in vitro, whereas no intrinsic kinase activity was detected in PAF-C samples. Significantly, PAF-C purifications combined with stable isotope labeling in cells (SILAC) quantitation for PAF-C phosphorylation from wild-type and CKII temperature-sensitive strains (cka1Δ cka2–8) showed that PAF-C phosphorylation at consensus CKII sites is significantly reduced in cka1Δ cka2–8 strains. Consistent with a role of CKII in FACT and PAF-C function, we show that decreased CKII function in vivo results in decreased levels of histone H2B lysine 123 monoubiquitylation, a modification dependent on FACT and PAF-C. Taken together, our results define a coordinated role of CKII and FACT in the regulation of RNA polymerase II transcription through chromatin via phosphorylation of PAF-C

    Methodological Challenges of Researching Positive Action Measures

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    This paper highlights some ofthe methodological challenges which have arisen in collecting data for an international study on positive action measures. It will describe strategies employed to encourage participation in the study from as wide a range of organisations and individuals using a mixed method approach. The paper will also discuss the methodological and sensitive issues related to this type of research in organisations and strategies adopted by the research team to ameliorate any problems that have arisen whilst maintaining trustworthiness and rigour in the study
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