Edward Irving: Coleridge, Sign, and Symbol

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(η5-Cyclopentadienyl)(2-naphthylethynyl)(triphenylphosphine-κP)nickel(II)

The title compound, [Ni(C₅H₅)(C₁₂H₇)(C₁₈H₁₅P)], does not contain strong hydrogen-bond donors or acceptors and the primary interactions are limited to those of the weak C-H...π(arene) type and mainly involving the arene rings

Niche Markets

Is evolutionary theory is incomplete and are we failing to understand phenomena as disparate as ecosystem development and the interplay of genes and culture in shaping human evolution

Enabling Factor Analysis on Thousand-Subject Neuroimaging Datasets

The scale of functional magnetic resonance image data is rapidly increasing as large multi-subject datasets are becoming widely available and high-resolution scanners are adopted. The inherent low-dimensionality of the information in this data has led neuroscientists to consider factor analysis methods to extract and analyze the underlying brain activity. In this work, we consider two recent multi-subject factor analysis methods: the Shared Response Model and Hierarchical Topographic Factor Analysis. We perform analytical, algorithmic, and code optimization to enable multi-node parallel implementations to scale. Single-node improvements result in 99x and 1812x speedups on these two methods, and enables the processing of larger datasets. Our distributed implementations show strong scaling of 3.3x and 5.5x respectively with 20 nodes on real datasets. We also demonstrate weak scaling on a synthetic dataset with 1024 subjects, on up to 1024 nodes and 32,768 cores

Likelihood of Spontaneous Conversion of Atrial Fibrillation to Sinus Rhythm

AbstractObjectives. We sought to determine the likelihood and predictors of spontaneous conversion to sinus rhythm of recent-onset atrial fibrillation (symptoms <72 h).Background. Although spontaneous conversion of recent-onset atrial fibrillation is common, the likelihood and clinical and echocardiographic predictors have not been fully defined. Such data would be important for management of patients in whom early cardioversion is desired: Cardioversion could be delayed in patients with a high likelihood of spontaneous conversion, and it could be expeditiously pursued if spontaneous conversion is unlikely.Methods. We screened 1,822 consecutive adults admitted to the hospital with atrial fibrillation and prospectively identified 356 patients (45% male, mean age ± SD 68 ± 16 years) with atrial fibrillation of <72-h duration. The occurrence of spontaneous conversion to sinus rhythm and clinical and echocardiographic data were identified through retrospective chart review.Results. Spontaneous conversion to sinus rhythm occurred in 68% of the study group (n = 242; 95% confidence interval [CI] 63% to 73%). Among patients with spontaneous conversion, the total duration of atrial fibrillation was <24 h in 159 (66%), 24 to 48 h in 42 (17%) and >48 h in 41 (17%) (p < 0.001). Logistic regression analysis of clinical data identified presentation <24 h from onset of symptoms as the only predictor of spontaneous conversion (odds ratio 1.8, 95% CI 1.4 to 2.4, p < 0.0001). Normal left ventricular systolic function was more common among patients with spontaneous conversion (p = 0.03), but it was not an independent predictor of conversion. Left atrial dimension was similar between groups.Conclusions. Spontaneous conversion to sinus rhythm occurs in almost 70% of patients presenting with atrial fibrillation of <72-h duration. Presentation with symptoms of <24-h duration is the best predictor of spontaneous conversion

The impact of greyscale inversion for nodule detection in an anthropomorphic chest phantom: a free-response observer study

Objective: The aim of this work was to assess the impact of greyscale inversion on nodule detection on poster- oanterior chest X-ray images. Previous work has attemp- ted this, with no consensus opinion formed. We assessed the value of “fast-flicking” between standard and inverted display modes for nodule detection. Methods: Six consultant radiologists (with 5–32 years’ reporting experience) completed an observer task under the free-response paradigm. An anthropomorphic chest phantom was loaded with 50 different configurations of simulated nodules (1–4 nodules per case) measuring 5, 8, 10 and 12mm in spherical diameter; each configuration represented a single case. In addition, 25 cases contained no nodules. Images were displayed in three modes: (i) standard, (ii) inverted and (iii) fast-flicking between standard and inverted display modes. Each observer completed the study in a different order of display (i, ii, iii) using a calibrated 5-megapixel monitor. Nodules were localized with mouse clicks and ratings assigned using a 1–10 discrete slider-bar confidence scale. Rjafroc (Pitts- burgh, PA) was used for data analysis; differences in nodule detection performance were considered significant at 0.05. Results: The observer-averaged weighted jackknife alter- native free-response receiver-operating characteristic figures of merit were 0.715 (standard), 0.684 (inverted) and 0.717 (fast-flicking). Random-reader fixed-case anal- ysis revealed no statistically significant difference be- tween any treatment pair [F(2,8) 5 1.22; p 5 0.345]. Conclusion: No statistically significant difference in nodule detection was found for the three display conditions. Advances in knowledge: We have investigated the impact of fast-flicking between standard and inverted display modes for the detection of nodules. We found no benefit