1,238 research outputs found

    Complex Spiral Structure in the HD 100546 Transitional Disk as Revealed by GPI and MagAO

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    We present optical and near-infrared high-contrast images of the transitional disk HD 100546 taken with the Magellan Adaptive Optics system (MagAO) and the Gemini Planet Imager (GPI). GPI data include both polarized intensity and total intensity imagery, and MagAO data are taken in Simultaneous Differential Imaging mode at Hα. The new GPI H-band total intensity data represent a significant enhancement in sensitivity and field rotation compared to previous data sets and enable a detailed exploration of substructure in the disk. The data are processed with a variety of differential imaging techniques (polarized, angular, reference, and simultaneous differential imaging) in an attempt to identify the disk structures that are most consistent across wavelengths, processing techniques, and algorithmic parameters. The inner disk cavity at 15 au is clearly resolved in multiple data sets, as are a variety of spiral features. While the cavity and spiral structures are identified at levels significantly distinct from the neighboring regions of the disk under several algorithms and with a range of algorithmic parameters, emission at the location of HD 100546 "c" varies from point-like under aggressive algorithmic parameters to a smooth continuous structure with conservative parameters, and is consistent with disk emission. Features identified in the HD 100546 disk bear qualitative similarity to computational models of a moderately inclined two-armed spiral disk, where projection effects and wrapping of the spiral arms around the star result in a number of truncated spiral features in forward-modeled images

    Improved Test Planning and Analysis Through the Use of Advanced Statistical Methods

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    The goal of this work is, through computational simulations, to provide statistically-based evidence to convince the testing community that a distributed testing approach is superior to a clustered testing approach for most situations. For clustered testing, numerous, repeated test points are acquired at a limited number of test conditions. For distributed testing, only one or a few test points are requested at many different conditions. The statistical techniques of Analysis of Variance (ANOVA), Design of Experiments (DOE) and Response Surface Methods (RSM) are applied to enable distributed test planning, data analysis and test augmentation. The D-Optimal class of DOE is used to plan an optimally efficient single- and multi-factor test. The resulting simulated test data are analyzed via ANOVA and a parametric model is constructed using RSM. Finally, ANOVA can be used to plan a second round of testing to augment the existing data set with new data points. The use of these techniques is demonstrated through several illustrative examples. To date, many thousands of comparisons have been performed and the results strongly support the conclusion that the distributed testing approach outperforms the clustered testing approach

    Speech and communication in Parkinson’s disease: a cross-sectional exploratory study in the UK

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    Objective: To assess associations between cognitive status, intelligibility, acoustics and functional communication in PD. Design: Cross-sectional exploratory study of functional communication, including a within-participants experimental design for listener assessment. Setting: A major academic medical centre in the East of England, UK. Participants: Questionnaire data were assessed for 45 people with Parkinson’s disease (PD), who had self-reported speech or communication difficulties and did not have clinical dementia. Acoustic and listener analyses were conducted on read and conversational speech for 20 people with PD and 20 familiar conversation partner controls without speech, language or cognitive difficulties. Main outcome measures: Functional communication assessed by the Communicative Participation Item Bank (CPIB) and Communicative Effectiveness Survey (CES). Results: People with PD had lower intelligibility than controls for both the read (mean difference 13.7%, p=0.009) and conversational (mean difference 16.2%, p=0.04) sentences. Intensity and pause were statistically significant predictors of intelligibility in read sentences. Listeners were less accurate identifying the intended emotion in the speech of people with PD (14.8% point difference across conditions, p=0.02) and this was associated with worse speaker cognitive status (16.7% point difference, p=0.04). Cognitive status was a significant predictor of functional communication using CPIB (F=8.99, p=0.005, η2 = 0.15) but not CES. Intelligibility in conversation sentences was a statistically significant predictor of CPIB (F=4.96, p=0.04, η2 = 0.19) and CES (F=13.65, p=0.002, η2 = 0.43). Read sentence intelligibility was not a significant predictor of either outcome. Conclusions: Cognitive status was an important predictor of functional communication—the role of intelligibility was modest and limited to conversational and not read speech. Our results highlight the importance of focusing on functional communication as well as physical speech impairment in speech and language therapy (SLT) for PD. Our results could inform future trials of SLT techniques for PD

    Adipose Tissue Inflammation in Diabetic versus Non-diabetic Pregnancies

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    Objective: Beyond weight associated with fetus, placenta, amniotic fluid and increased blood volume, adipose tissue (AT) expansion is an accepted and expected component of pregnancy weight gain. Normal pregnancy is associated with relative insulin resistance (IR). In non-pregnant humans, AT expansion has been associated with IR and AT inflammation. However, it is not known whether AT expansion and IR in pregnancy are also associated with AT inflammation. This pilot study examined relationships between AT expansion and inflammation in control versus diabetic pregnancies. Methods: Eligible subjects undergoing scheduled Cesarean delivery for obstetric indications were prospectively enrolled. Subjects provided demographic and anthropometric data, and biologic specimens. Immunofluorescence microscopy was performed on subcutaneous (SQ) and omental (OM) AT samples to evaluate macrophage infiltration. Included gravidas had paired AT samples and either negative glucola screening (controls) or gestational or pre-gestational Type 2 diabetes mellitus (T2DM). Results: 13 subjects with SQ and OM AT samples were evaluated (10-controls, 3-diabetics (2-T2DM and 1-GDM)). Mean BMI and gestational weight gain of controls was 27.8 kg/m2 (range 19.5-42) and 27.6 pounds (range 15-36) and of diabetics was 30.6 kg/m2 (range 30-33) and 19 pounds (range -3-30), respectively. Macrophage infiltration was seen in OM AT from 2/ 3 diabetics and 0/ 10 controls (see figure). Conclusions: These results indicate that AT expansion in non-diabetic pregnancies is not accompanied by macrophage infiltration. Thus, the IR of normal pregnancy is unlikely to be related to AT inflammation, and AT expansion per se does not lead to AT inflammation. However, as has been reported for T2DM in non-pregnant humans, the presence (T2DM) or development (GDM) of diabetes in pregnancy is associated with macrophage infiltration of AT. Despite the small sample size, the observed large differences in macrophage infiltration between controls and diabetics suggest that these findings will persist in a larger cohort

    Dynamical Mass Measurement of the Young Spectroscopic Binary V343 Normae AaAb Resolved With the Gemini Planet Imager

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    We present new spatially resolved astrometry and photometry from the Gemini Planet Imager of the inner binary of the young multiple star system V343 Normae, which is a member of the beta Pictoris moving group. V343 Normae comprises a K0 and mid-M star in a ~4.5 year orbit (AaAb) and a wide 10" M5 companion (B). By combining these data with archival astrometry and radial velocities we fit the orbit and measure individual masses for both components of M_Aa = 1.10 +/- 0.10 M_sun and M_Ab = 0.290 +/- 0.018 M_sun. Comparing to theoretical isochrones, we find good agreement for the measured masses and JHK band magnitudes of the two components consistent with the age of the beta Pic moving group. We derive a model-dependent age for the beta Pic moving group of 26 +/- 3 Myr by combining our results for V343 Normae with literature measurements for GJ 3305, which is another group member with resolved binary components and dynamical masses.Comment: 12 pages, 7 figures. Accepted to A

    Improving and Assessing Planet Sensitivity of the GPI Exoplanet Survey with a Forward Model Matched Filter

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    We present a new matched filter algorithm for direct detection of point sources in the immediate vicinity of bright stars. The stellar Point Spread Function (PSF) is first subtracted using a Karhunen-Lo\'eve Image Processing (KLIP) algorithm with Angular and Spectral Differential Imaging (ADI and SDI). The KLIP-induced distortion of the astrophysical signal is included in the matched filter template by computing a forward model of the PSF at every position in the image. To optimize the performance of the algorithm, we conduct extensive planet injection and recovery tests and tune the exoplanet spectra template and KLIP reduction aggressiveness to maximize the Signal-to-Noise Ratio (SNR) of the recovered planets. We show that only two spectral templates are necessary to recover any young Jovian exoplanets with minimal SNR loss. We also developed a complete pipeline for the automated detection of point source candidates, the calculation of Receiver Operating Characteristics (ROC), false positives based contrast curves, and completeness contours. We process in a uniform manner more than 330 datasets from the Gemini Planet Imager Exoplanet Survey (GPIES) and assess GPI typical sensitivity as a function of the star and the hypothetical companion spectral type. This work allows for the first time a comparison of different detection algorithms at a survey scale accounting for both planet completeness and false positive rate. We show that the new forward model matched filter allows the detection of 50%50\% fainter objects than a conventional cross-correlation technique with a Gaussian PSF template for the same false positive rate.Comment: ApJ accepte
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