670 research outputs found

    Hypothesis Testing For Network Data in Functional Neuroimaging

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    In recent years, it has become common practice in neuroscience to use networks to summarize relational information in a set of measurements, typically assumed to be reflective of either functional or structural relationships between regions of interest in the brain. One of the most basic tasks of interest in the analysis of such data is the testing of hypotheses, in answer to questions such as "Is there a difference between the networks of these two groups of subjects?" In the classical setting, where the unit of interest is a scalar or a vector, such questions are answered through the use of familiar two-sample testing strategies. Networks, however, are not Euclidean objects, and hence classical methods do not directly apply. We address this challenge by drawing on concepts and techniques from geometry, and high-dimensional statistical inference. Our work is based on a precise geometric characterization of the space of graph Laplacian matrices and a nonparametric notion of averaging due to Fr\'echet. We motivate and illustrate our resulting methodologies for testing in the context of networks derived from functional neuroimaging data on human subjects from the 1000 Functional Connectomes Project. In particular, we show that this global test is more statistical powerful, than a mass-univariate approach. In addition, we have also provided a method for visualizing the individual contribution of each edge to the overall test statistic.Comment: 34 pages. 5 figure

    LDA+DMFT Approach to Magnetocrystalline Anisotropy of Strong Magnets

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    The new challenges posed by the need of finding strong rare-earth free magnets demand methods that can predict magnetization and magnetocrystalline anisotropy energy (MAE). We argue that correlated electron effects, which are normally underestimated in band structure calculations, play a crucial role in the development of the orbital component of the magnetic moments. Because magnetic anisotropy arises from this orbital component, the ability to include correlation effects has profound consequences on our predictive power of the MAE of strong magnets. Here we show that incorporating the local effects of electronic correlations with dynamical mean-field theory provides reliable estimates of the orbital moment, the mass enhancement and the MAE of YCo5.Comment: 7 pages, 4 figures, published versio

    Visual Outcomes, Efficacy, and Surgical Complications Associated with Intracameral Phenylephrine 1.0%/Ketorolac 0.3% Administered During Cataract Surgery

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    Aim: The purpose of this study was to compare visual outcomes, surgical time, and perioperative surgical complications after intracameral use of either phenylephrine/ketorolac (P/K) or epinephrine (Epi) during cataract surgery.Methods: This was a single-center, retrospective case review of patients undergoing cataract surgery from August to November 2015. Of the 641 eyes of 389 patients who underwent cataract surgery, 260 eyes were administered phenylephrine 1.0%/ketorolac 0.3% and 381 eyes received Epi in the irrigation solution intraoperatively. All patients received a topical nonsteroidal anti-inflammatory drug regimen (bromfenac 0.07%, nepafenac 0.3%, or ketorolac 0.5%) for 3 days before surgery and topical tropicamide 1.0%, cyclopentolate 1.0%, and phenylephrine 2.5% on the day of surgery.Results: Mean length of surgery (LOS) was 15.4±0.6 minutes. Although a positive correlation was noted between patient age and LOS (p\u3c0.001), P/K was associated with a decrease in the LOS, when controlled for age quartiles. A statistically significant lower incidence of complications (1.1%) was observed with P/K use than Epi (4.5%; p=0.018). Among surgeons who used mydriatic-assist devices more frequently, P/K use was associated with a reduction in the use of these devices (p\u3c0.001). When controlling for age quartile, patients of age groups 69–76 and 76–92 years who received P/K had significantly better uncorrected visual acuity at postoperative day 1 than those receiving Epi (p=0.003).Conclusion: Intracameral use of phenylephrine 1.0%/ketorolac 0.3% during cataract surgery may be effective in maintaining mydriasis. It appears to be superior to intracameral Epi at reducing intraoperative and postoperative complications, need for pupillary dilating devices, and surgical time

    A fully 3-dimensional thermal model of a comet nucleus

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    A 3-D numerical model of comet nuclei is presented. An implicit numerical scheme was developed for the thermal evolution of a spherical nucleus composed of a mixture of ice and dust. The model was tested against analytical solutions, simplified numerical solutions, and 1-D thermal evolution codes. The 3-D code was applied to comet 67P/Churyumov-Gerasimenko; surface temperature maps and the internal thermal structure was obtained as function of depth, longitude and hour angle. The effect of the spin axis tilt on the surface temperature distribution was studied in detail. It was found that for small tilt angles, relatively low temperatures may prevail on near-pole areas, despite lateral heat conduction. A high-resolution run for a comet model of 67P/Churyumov-Gerasimenko with low tilt angle, allowing for crystallization of amorphous ice, showed that the amorphous/crystalline ice boundary varies significantly with depth as a function of cometary latitude.Comment: 19 pages, 10 figure

    AGS Position Statement: Making Medical Treatment Decisions for Unbefriended Older Adults

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135987/1/jgs14586_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135987/2/jgs14586.pd
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