Periodic cometary showers: Real or imaginary?

Since the initial reports in 1980, a considerable body of chemical and physical evidence has been accumulated to indicate that a major impact event occurred on earth 65 million years ago. The effects of this event were global in extent and have been suggested as the cause of the sudden demise or mass extinction of a large percentage of life, including the dinosaurs, at the end of the geologic time period known as the Cretaceous. Recent statistical analyses of extinctions in the marine faunal record for the last 250 million years have suggested that mass extinctions may occur with a periodicity of every 26 to 30 million years. Following these results, other workers have attempted to demonstrate that these extinction events, like that at the end of the Cretaceous, are temporally correlated with large impact events. A recent scenario suggests that they are the result of periodic showers of comets produced by either the passage of the solar system through the galactic plane or by perturbations of the cometary cloud in the outer solar system by a, as yet unseen, solar companion. This hypothesized solar companion has been given the name Nemesis

Automated Bruch’s Membrane Opening Segmentation in Cases of Optic Disc Swelling in Combined 2D and 3D SD-OCT Images Using Shape-Prior and Texture Information

When the optic disc is swollen, the visibility of the Bruch’s membrane opening (BMO) is often drastically reduced in spectral-domain optical coherence tomography (SD-OCT) volumes. Recent work pro- posed a semi-automated method to segment the BMO using combined information from 2D high-definition raster and 3D volumetric SD-OCT scans; however, manual placement of six landmark points was required. In this work, we propose a fully automated approach to segment the BMO from 2D high-definition and 3D volumetric SD-OCT scans. Using the topographic shape of the internal limiting membrane and textural information near Bruch’s membrane, two BMO points are first estimated in the high-definition central B-scan and then registered into the corresponding volumetric scan. Utilizing the information from both the high- definition BMO estimates and the standard-definition SD-OCT volume, the cost image was created. A graph-based algorithm with soft shape-based constraints is further applied to segment the BMO contour on the SD-OCT en-face image domain. Using a set of 23 volumes with reasonably centered raster scans and swelling larger than 14.42 mm3, the fully automated approach was significantly more accurate than a traditional approach utilizing information only from the SD-OCT volume (RMS error of 7.18 vs. 21.37 in pixels; p < 0.05) and had only a slightly higher (and not significantly different) error than the previously proposed semi-automated approach (RMS error of 7.18 vs. 5.30 in pixels; p = 0.08)

Geographic variation in malarial parasite lineages in the Common Yellowthroat (Geothlypis trichas)

Our current understanding of migration routes of many birds is limited and researchers have employed various methods to determine migratory patterns. Recently, parasites have been used to track migratory birds. The objective of this study was to determine whether haemosporidian parasite lineages detect significant geographic structure in common yellowthroats (Geothlypis trichas). We examined liver tissue or blood from 552 birds sampled from multiple locations throughout the continental United States, southern Canada, and the Bahamas. We found a 52.7% overall prevalence of haematozoan infection. We identified 86.1% of these infections to genus: 81% were Plasmodium; 5% were Haemoproteus; and 0.1% were Leucocytozoon. There were significant differences in the prevalence of different parasite genera among regions (χ2 = 36.82, P \u3c 0.0001) and in the proportion of Plasmodium infections versus other parasites among regions (χ2 = 35.52, P \u3c 0.0001). Sequence information identified three Haemoproteus lineages, two Leucocytozoon lineages, and thirteen Plasmodium lineages. Due to the low number of Haemoproteus and Leucocytozoon, only Plasmodium lineages were used in the geographic comparison of lineages. Six Plasmodium lineages were found in eight or more birds and the prevalence of these varied significantly among regions (χ2 = 172.33, P \u3c 0.0001). Additionally, 45 juvenile birds were sampled to determine what parasites could be obtained in the breeding grounds and we found only one lineage. In conclusion, parasite lineages show some geographic structure, with some lineages being more geographically specific than others, but are not useful for determining migratory connectivity in this species

Critical Care Nurses\u27 Beliefs About and Reported Management of Anxiety

Background: Anxiety is associated with increased morbidity and mortality. Critical care nurses are uniquely positioned to reduce anxiety in their patients. Critical care nurses\u27 beliefs about and frequency of use of strategies to reduce anxiety have not been studied. Objectives: To explore critical care nurses\u27 beliefs about the importance of anxiety management and to describe nurses\u27 reported use of strategies to manage anxiety in their patients. Methods: A random sample (N = 2500) of members of the American Association of Critical-Care Nurses was asked to complete the Critical Care Nurse Anxiety Identification and Management Survey. Results: Respondents (n = 783) were primarily female (92%), white (88.5%) staff nurses (74.1%) who thought that anxiety is potentially harmful (mean, 4.1; SD, 0.8; range, 1 = no harm to 5 = life-threatening harm), that anxiety management is important (mean, 4.8; SD 0.6; range, 1 = no benefit to 5 = profound benefit). A majority commonly used pharmacological management; most also used information and communication interventions. Fewer subjects used the presence of patients\u27 family members to alleviate patients\u27 anxiety; few reported using stress-reduction techniques. Conclusion: Most respondents thought that treating anxiety is important and beneficial. Commonly used strategies included pharmacological relief of anxiety and pain and information and communication interventions. Although these strategies are useful, they may not effectively reduce anxiety in all patients

Segmentation of the Retinal Vasculature within Spectral-Domain Optical Coherence Tomography Volumes of Mice

Automated approaches for the segmentation of the retinal vessels are helpful for longitudinal studies of mice using spectral-domain optical coherence tomography (SD-OCT). In the SD-OCT volumes of human eyes, the retinal vasculature can be readily visualized by creating a projected average intensity image in the depth direction. The created projection images can then be segmented using standard approaches. However, in the SD-OCT volumes of mouse eyes, the creation of projection images from the entire volume typically results in very poor images of the vasculature. The purpose of this work is to present and evaluate three machine-learning approaches, namely baseline, single-projection, and all-layers approaches, for the automated segmentation of retinal vessels within SD-OCT volumes of mice. Twenty SD-OCT volumes (400 × 400 × 1024 voxels) from the right eyes of twenty mice were obtained using a Bioptigen SD-OCT machine (Morrisville, NC) to evaluate our methods. The area under the curve (AUC) for the receiver operating characteristic (ROC) curves of the all-layers approach, 0.93, was significantly larger than the AUC for the single-projection (0.91) and baseline (0.88) approach with p < 0.05

Critical Care Nurses\u27 Assessment of Patients\u27 Anxiety: Reliance on Physiological and Behavioral Parameters

Background: Anxiety activates the sympathetic nervous system and hypothalamic-pituitary-adrenal axis and may increase morbidity and mortality in vulnerable critical care patients. Despite the adverse effects of anxiety, little is known about critical care nurses\u27 practices for assessing anxiety. Objective: To determine the importance that critical care nurses place on evaluating anxiety and to describe clinical indicators used to assess anxiety. Methods: Twenty-five hundred members of the American Association of Critical-Care Nurses received the Critical Care Nurse Anxiety Identification and Management Survey and were asked to rate the importance of anxiety assessment, to rate the importance of 61 anxiety indicators, and to select and rank the 5 most important anxiety indicators. Results: Seven hundred eighty-three completed surveys (31.6%) were returned by female (92.0%), white (88.6%) staff nurses (74.2%) who practiced critical care nursing 32.5 hours (SD, 12.3 hours) weekly. Nearly three quarters (71.3%) of respondents thought that anxiety assessment is very important. Only 2 indicators, agitation and patients\u27 verbalization of anxiety, were rated as very important to anxiety assessment. Thirty-nine indicators rated as important primarily included measurable physiological changes and observable behaviors. The top 5 anxiety indicators were agitation, increased blood pressure, increased heart rate, patients\u27 verbalization of anxiety, and restlessness. Conclusion: Important indicators of anxiety included observable behaviors and measurable physiological changes. Reliance on these criteria may produce an inaccurate and incomplete anxiety evaluation in vulnerable patients and lead to poorer outcomes. A comprehensive, systematic anxiety assessment tool for valid and reproducible evaluation of patients\u27 anxiety is needed

Hybrid Algorithms Based on Integer Programming for the Search of Prioritized Test Data in Software Product Lines

In Software Product Lines (SPLs) it is not possible, in general, to test all products of the family. The number of products denoted by a SPL is very high due to the combinatorial explosion of features. For this reason, some coverage criteria have been proposed which try to test at least all feature interactions without the necessity to test all products, e.g., all pairs of features (pairwise coverage). In addition, it is desirable to first test products composed by a set of priority features. This problem is known as the Prioritized Pairwise Test Data Generation Problem. In this work we propose two hybrid algorithms using Integer Programming (IP) to generate a prioritized test suite. The first one is based on an integer linear formulation and the second one is based on a integer quadratic (nonlinear) formulation. We compare these techniques with two state-of-the-art algorithms, the Parallel Prioritized Genetic Solver (PPGS) and a greedy algorithm called prioritized-ICPL. Our study reveals that our hybrid nonlinear approach is clearly the best in both, solution quality and computation time. Moreover, the nonlinear variant (the fastest one) is 27 and 42 times faster than PPGS in the two groups of instances analyzed in this work.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Partially funded by the Spanish Ministry of Economy and Competitiveness and FEDER under contract TIN2014-57341-R, the University of Málaga, Andalucía Tech and the Spanish Network TIN2015-71841-REDT (SEBASENet)

In Vitro Culture of Cells Exfoliated in the Urine by Patients with Diabetes Mellitus

As an approach to facilitate the understanding of the progression of diabetic renal disease, we assessed the urine of diabetic patients and normal volunteers for the presence of cells that could be cultured in vitro. The results suggest that both normal control subjects and diabetic patients, without clinically detectable microangiopathy, exfoliate few culturable cells into the urine. In contrast, diabetics with documented retinopathy but without nephropathy exfoliate substantially higher numbers of culturable cells (5.2 cells/100 ml urine), whereas diabetics with both retinopathy and advanced nephropathy exfoliate even greater numbers of culturable cells (50.8 cells/100 ml urine). The cells that are exfoliated and culturable can be divided into five distinct cell types based on morphology at the light microscope level. The exfoliated cells proliferate at clonal density after isolation from urine and are epithelial in appearance. These data suggest that the culture of cells from urine might have diagnostic value as an early indicator of diabetic renal disease and provide a convenient, noninvasive new source of human kidney epithelial cells

Multimodal Graph-Theoretic Approach for Segmentation of the Internal Limiting Membrane at the Optic Nerve Head

In this work, we present a multimodal multiresolution graph-based method to segment the top surface of the retina called the internal limiting membrane (ILM) within optic-nerve-head-centered spectral-domain optical coherence tomography (SD-OCT) volumes. Having a precise ILM surface is crucial as this surface is utilized for measuring several structural parameters such as Bruch’s membrane opening-minimum rim width (BMO-MRW) and cup volume. The proposed method addresses the common current segmentation errors due to the presence of retinal blood vessels, deep cupping, or a very steep slope of the ILM. In order to resolve these issues, the volume is resampled using a set of gradient vector flow (GVF) based columns. The GVF field is computed according to an initial surface segmentation which is obtained through a multiresolution framework. The retinal blood vessel information (obtained from corresponding registered fundus photographs) along with shape prior information are incorporated in a graph-theoretic approach to compute the ILM segmentation. The method is tested on the SD-OCT volumes from 44 glaucoma subjects and significantly smaller errors were obtained than that from current approaches