580 research outputs found

    Overview of the SAPHIRA Detector for AO Applications

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    We discuss some of the unique details of the operation and behavior of Leonardo SAPHIRA detectors, particularly in relation to their usage for adaptive optics wavefront sensing. SAPHIRA detectors are 320×\times256@24 μ\mum pixel HgCdTe linear avalanche photodiode arrays and are sensitive to 0.8-2.5 μm\mu m light. SAPHIRA arrays permit global or line-by-line resets, of the entire detector or just subarrays of it, and the order in which pixels are reset and read enable several readout schemes. We discuss three readout modes, the benefits, drawbacks, and noise sources of each, and the observational modes for which each is optimal. We describe the ability of the detector to read subarrays for increased frame rates, and finally clarify the differences between the avalanche gain (which is user-adjustable) and the charge gain (which is not).Comment: 13 pages, 4 figures, 2 tables, accepted to JATI

    Defects in lysosomal maturation facilitate the activation of innate sensors in systemic lupus erythematosus

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    Activation of innate sensors by self-antigen contributes to autoimmunity, although how intracellular sensors are chronically exposed to self-antigen has remained unknown. Here, we identify a previously unidentified defect in which lupus-prone macrophages fail to mature the lysosome, promoting the accumulation of apoptotic debris-containing IgG–immune complexes (IgG-ICs). Interestingly, macrophages from other autoimmune diseases accumulate IgG-ICs, indicating that lysosomal defects may underlie multiple autoimmune diseases. Furthermore, the prolonged intracellular residency chronically activates Toll-like receptors and permeabilizes the phagolysosomal membrane, allowing activation of cytosolic sensors. These findings identify lysosomal maturation as a unique defect in MRL/lpr mice that impacts multiple events known to underlie SLE, including pathogenic cytokine secretion

    Electrostatic model of atomic ordering in complex perovskite alloys

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    We present a simple ionic model which successfully reproduces the various types of compositional long-range order observed in a large class of complex insulating perovskite alloys. The model assumes that the driving mechanism responsible for the ordering is simply the electrostatic interaction between the different ionic species. A possible new explanation for the anomalous long-range order observed in some Pb relaxor alloys, involving the proposed existence of a small amount of Pb^4+ on the B sublattice, is suggested by an analysis of the model.Comment: 4 pages, two-column style with 1 postscript figure embedded. Uses REVTEX and epsf macros. Also available at http://www.physics.rutgers.edu/~dhv/preprints/index.html#lb_orde

    Prescribers\u27 Satisfaction with Delivering Medications for Opioid Use Disorder

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    BACKGROUND: Expanding access to medications for opioid use disorder (MOUD), such as buprenorphine and extended release (XR) naltrexone, is critical to addressing the US opioid epidemic, but little is known about prescriber satisfaction with delivering these two types of MOUD. The current study describes the satisfaction of prescribers delivering buprenorphine and XR-naltrexone while examining whether satisfaction is associated with current patient census and organizational environment. METHODS: As part of a cluster randomized clinical trial (RCT) focused on expanding access to medication for opioid use disorder, 41 MOUD prescribers in Florida, Ohio, and Wisconsin completed a web-based survey. The survey included measures of prescriber satisfaction with delivering buprenorphine treatment and XR-naltrexone. In addition, the survey measured several prescriber characteristics and their perceptions of the organizational environment. RESULTS: Prescribers were generally satisfied with their work in delivering these two types of MOUD. Prescribers reporting a greater number of patients (r = .46, p = .006), those who would recommend the center to others (r = .56, p \u3c .001), and those reporting positive relationships with staff (r = .56, p \u3c .001) reported significantly greater overall satisfaction with delivering buprenorphine treatment. Prescribers who more strongly endorsed feeling overburdened reported lower overall buprenorphine satisfaction (r = -.37, p = .02). None of the prescriber characteristics or perceptions of the organizational environment were significantly associated with overall satisfaction with delivering XR-naltrexone treatment. CONCLUSIONS: The generally high levels of satisfaction with both types of MOUD is notable given that prescriber dissatisfaction can lead to turnover and impact intentions to leave the profession. Future research should continue to explore the prescriber characteristics and organizational factors associated with satisfaction in providing different types of MOUD. REGISTRATION: ClinicalTrials.gov. NCT02926482. Date of registration: September 9, 2016. https://clinicaltrials.gov/ct2/show/NCT02926482

    Modeling capping protein FRAP and CALI experiments reveals in vivo regulation of actin dynamics

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    To gain insights on cellular mechanisms regulating actin polymerization, we used the Virtual Cell to model FRAP and chromophore assisted laser inactivation (CALI) experiments on EGFP-capping protein (EGFP-CP). Modeling the FRAP kinetics demonstrated that the in vivo rate for the dissociation of CP from actin filaments is much faster (~0.1 s−1) than that measured in vitro (0.01–0.0004 s−1). The CALI simulation revealed that in order to induce sustainable changes in cell morphology after CP inactivation, the cells should exhibit anti-capping ability. We included the VASP protein as the anti-capping agent in the modeling scheme. The model predicts that VASP affinity for barbed ends has a cooperative dependence on the concentration of VASP-barbed end complexes. This dependence produces a positive feedback that stabilizes the complexes and allows sustained growth at clustered filament tips. We analyzed the range of laser intensities that are sufficient to induce changes in cell morphology. This analysis demonstrates that FRAP experiments with EGFP-CP can be performed safely without changes in cell morphology, because, the intensity of the photobleaching beam is not high enough to produce the critical concentration of free barbed ends that will induce filament growth before diffusional replacement of EGFP-CP occurs

    “Maybe I Made Up the Whole Thing”: Placebos and Patients’ Experiences in a Randomized Controlled Trial

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    Patients in the placebo arms of randomized controlled trials (RCT) often experience positive changes from baseline. While multiple theories concerning such “placebo effects” exist, peculiarly, none has been informed by actual interviews of patients undergoing placebo treatment. Here, we report on a qualitative study (n = 27) embedded within a RCT (n = 262) in patients with irritable bowel syndrome. Besides identical placebo acupuncture treatment in the RCT, the qualitative study patients also received an additional set of interviews at the beginning, midpoint, and end of the trial. Interviews of the 12 qualitative subjects who underwent and completed placebo treatment were transcribed. We found that patients (1) were persistently concerned with whether they were receiving placebo or genuine treatment; (2) almost never endorsed “expectation” of improvement but spoke of “hope” instead and frequently reported despair; (3) almost all reported improvement ranging from dramatic psychosocial changes to unambiguous, progressive symptom improvement to tentative impressions of benefit; and (4) often worried whether their improvement was due to normal fluctuations or placebo effects. The placebo treatment was a problematic perturbation that provided an opportunity to reconstruct the experiences of the fluctuations of their illness and how it disrupted their everyday life. Immersion in this RCT was a co-mingling of enactment, embodiment and interpretation involving ritual performance and evocative symbols, shifts in bodily sensations, symptoms, mood, daily life behaviors, and social interactions, all accompanied by self-scrutiny and re-appraisal. The placebo effect involved a spectrum of factors and any single theory of placebo—e.g. expectancy, hope, conditioning, anxiety reduction, report bias, symbolic work, narrative and embodiment—provides an inadequate model to explain its salubrious benefits

    Evidence for Spin–Orbit Alignment in the TRAPPIST-1 System

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    In an effort to measure the Rossiter–McLaughlin effect for the TRAPPIST-1 system, we performed high-resolution spectroscopy during transits of planets e, f, and b. The spectra were obtained with the InfraRed Doppler spectrograph on the Subaru 8.2 m telescope, and were supplemented with simultaneous photometry obtained with a 1 m telescope of the Las Cumbres Observatory Global Telescope. By analyzing the anomalous radial velocities, we found the projected stellar obliquity to be λ = 1 ± 28° under the assumption that the three planets have coplanar orbits, although we caution that the radial-velocity data show correlated noise of unknown origin. We also sought evidence for the expected deformations of the stellar absorption lines, and thereby detected the "Doppler shadow" of planet b with a false-alarm probability of 1.7%. The joint analysis of the observed residual cross-correlation map including the three transits gave λ = 19_(-15)^(+13)°. These results indicate that the the TRAPPIST-1 star is not strongly misaligned with the common orbital plane of the planets, although further observations are encouraged to verify this conclusion

    #Nationalism: the ethno-nationalist populism of Donald Trump’s Twitter communication

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    In this article, we explore the ethno-nationalist populism of Donald Trump’s Twitter communication during the 2016 presidential campaign. We draw on insights from ethno-symbolism – a perspective within nationalism studies – to analyse all 5,515 tweets sent by Trump during the campaign. We find that ethno-nationalist and populist themes were by far the most important component of Trump’s tweets, and that these themes built upon long-standing myths and symbols of an ethnic conception of American identity. In sum, Trump’s tweets depicted a virtuous white majority being threatened by several groups of immoral outsiders, who were identified by their foreignness, their religion, and their self-interestedness. The struggle against these groups was framed as a mission to restore America to a mythical golden age – to “Make America Great Again.

    Investigation of biochemical biorefinery sizing and environmental sustainability impacts for conventional bale system and advanced uniform biomass logistics designs

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    The 2011 US Billion-Ton Update1 estimates that there are enough agricultural and forest resources to sustainably provide enough biomass to displace approximately 30% of the country’s current petroleum consumption. A portion of these resources are inaccessible at current cost targets with conventional feedstock supply systems because of their remoteness or low yields. Reliable analyses and projections of US biofuels production depend on assumptions about the supply system and biorefinery capacity, which, in turn, depend on economics, feedstock logistics, and sustainability. A cross-functional team has examined optimal combinations of advances in feedstock supply systems and biorefinery capacities with rigorous design information, improved crop yield and agronomic practices, and improved estimates of sustainable biomass availability. Biochemical-conversion-to-ethanol is analyzed for conventional bale-based system and advanced uniform-format feedstock supply system designs. The latter involves ‘pre-processing’ biomass into a higher-density, aerobically stable, easily transportable format that can supply large-scale biorefineries. Feedstock supply costs, logistics and processing costs are analyzed and compared, taking into account environmental sustainability metrics
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