Grammar-Based Geodesics in Semantic Networks

A geodesic is the shortest path between two vertices in a connected network. The geodesic is the kernel of various network metrics including radius, diameter, eccentricity, closeness, and betweenness. These metrics are the foundation of much network research and thus, have been studied extensively in the domain of single-relational networks (both in their directed and undirected forms). However, geodesics for single-relational networks do not translate directly to multi-relational, or semantic networks, where vertices are connected to one another by any number of edge labels. Here, a more sophisticated method for calculating a geodesic is necessary. This article presents a technique for calculating geodesics in semantic networks with a focus on semantic networks represented according to the Resource Description Framework (RDF). In this framework, a discrete "walker" utilizes an abstract path description called a grammar to determine which paths to include in its geodesic calculation. The grammar-based model forms a general framework for studying geodesic metrics in semantic networks.Comment: First draft written in 200

The influence of deoxygenation on Caribbean coral larval settlement and early survival

Deoxygenation is emerging as a major threat to coral reefs where it can have catastrophic effects, including mass coral mortality. Some coral species cannot survive more than a few days of exposure to low oxygen conditions, while others can tolerate deoxygenation for weeks, suggesting that coral tolerance to lowered dissolved oxygen (DO) concentrations is species-specific. However, hypoxia thresholds for corals have not yet been fully defined, and more information is needed to understand if tolerance to deoxygenation is consistent across all life stages. In this study, we tested the influence of severe (1.5 mg L-1 DO) and intermediate (3.5 mg L-1 DO) deoxygenation on larval settlement and survival during the early recruitment life phase of Colpophyllia natans, Orbicella faveolata, and Pseudodiploria strigosa. Exposure to deoxygenation over a 3-day settlement period did not significantly impact larval survival nor settlement rates compared to ambient DO concentrations (6 mg L-1 DO) for all three species. However, recruit survivorship in C. natans and O. faveolata after further exposure to severe deoxygenation was reduced compared to intermediate deoxygenation and control DO conditions. After 45 days of exposure to severe deoxygenation only 2.5 ± 2.5% of the initial O. faveolata had survived the larval and recruit stages compared to 22.5 ± 4.5% in control oxygen conditions. Similarly, C. natans survival was 13.5 ± 6.0% under severe deoxygenation, compared to 41.0 ± 4.4% in the control treatment. In contrast, survival of P. strigosa larvae and recruits was not different under deoxygenation treatments compared to the control, and higher overall, relative to the other species, indicating that P. strigosa is more resilient to severe deoxygenation conditions during its earliest life stages. This study provides unique insights into species-specific variation in the tolerance of coral recruits to deoxygenation with implications for whether this life history stage may be a demographic bottleneck for three ecologically important Caribbean coral species. Given the increasing frequency and severity of deoxygenation events in Caribbean coastal waters, these results are an important contribution to the growing body of research on deoxygenation as a threat to coral reef persistence in the Anthropocene, with implications for conservation and restoration efforts integrating coral recruitment into reef recovery efforts

Embedding clinical interventions into observational studies

Novel approaches to observational studies and clinical trials could improve the cost-effectiveness and speed of translation of research. Hybrid designs that combine elements of clinical trials with observational registries or cohort studies should be considered as part of a long-term strategy to transform clinical trials and epidemiology, adapting to the opportunities of big data and the challenges of constrained budgets. Important considerations include study aims, timing, breadth and depth of the existing infrastructure that can be leveraged, participant burden, likely participation rate and available sample size in the cohort, required sample size for the trial, and investigator expertise. Community engagement and stakeholder (including study participants) support are essential for these efforts to succeed

CANDELS Observations Of The Structural Properties Of Cluster Galaxies At Z=1.62

We discuss the structural and morphological properties of galaxies in a z = 1.62 proto-cluster using near-IR imaging data from Hubble Space Telescope Wide Field Camera 3 data of the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS). The cluster galaxies exhibit a clear color-morphology relation: galaxies with colors of quiescent stellar populations generally have morphologies consistent with spheroids, and galaxies with colors consistent with ongoing star formation have disk-like and irregular morphologies. The size distribution of the quiescent cluster galaxies shows a deficit of compact (less than or similar to 1 kpc), massive galaxies compared to CANDELS field galaxies at z = 1.6. As a result, the cluster quiescent galaxies have larger average effective sizes compared to field galaxies at fixed mass at greater than 90% significance. Combined with data from the literature, the size evolution of quiescent cluster galaxies is relatively slow from z similar or equal to 1.6 to the present, growing as (1 + z)(-0.6 +/- 0.1). If this result is generalizable, then it implies that physical processes associated with the denser cluster region seem to have caused accelerated size growth in quiescent galaxies prior to z = 1.6 and slower subsequent growth at z < 1.6 compared to galaxies in the lower density field. The quiescent cluster galaxies at z = 1.6 have higher ellipticities compared to lower redshift samples at fixed mass, and their surface-brightness profiles suggest that they contain extended stellar disks. We argue that the cluster galaxies require dissipationless (i.e., gas-poor or "dry") mergers to reorganize the disk material and to match the relations for ellipticity, stellar mass, size, and color of early-type galaxies in z < 1 clusters.NASA NAS5-26555HST GO-12060NASA through from the Space Telescope Science Institute GO-12060European Research CouncilRoyal SocietyTexas AM UniversityGeorge P. and Cynthia Woods Institute for Fundamental Physics and AstronomyAstronom

CANDELS Observations of the Environmental Dependence of the Color-Mass-Morphology Relation at z = 1.6

We study the environmental dependence of color, stellar mass, and morphology by comparing galaxies in a forming cluster to those in the field at z = 1:6 with Hubble Space Telescope near-infrared imaging in the CANDELS/UDS field. We quantify the morphology of the galaxies using the effective radius, reff, and S\'ersic index, n. In both the cluster and field, approximately half of the bulge-dominated galaxies (n > 2) reside on the red sequence of the color-magnitude diagram, and most disk-dominated galaxies (n < 2) have colors expected for star-forming galaxies. There is weak evidence that cluster galaxies have redder rest-frame U - B colors and higher stellar masses compared to the field. Star-forming galaxies in both the cluster and field show no significant differences in their morphologies. In contrast, there is evidence that quiescent galaxies in the cluster have larger median effective radii and smaller S\'ersic indices compared to the field with a significance of 2?. These differences are most pronounced for galaxies at clustercentric distances 1 Mpc < Rproj < 1.5 Mpc, which have low S\'ersic indices and possibly larger effective radii, more consistent with star-forming galaxies at this epoch and in contrast to other quiescent galaxies. We argue that star-forming galaxies are processed under the influence of the cluster environment at distances greater than the cluster-halo virial radius. Our results are consistent with models where gas accretion onto these galaxies is suppressed from processes associated with the cluster environment.Comment: ApJ accepted, 19 pages, 10 figure

Ubiquitous outflows in DEEP2 spectra of star-forming galaxies at z=1.4

Galactic winds are a prime suspect for the metal enrichment of the intergalactic medium and may have a strong influence on the chemical evolution of galaxies and the nature of QSO absorption line systems. We use a sample of 1406 galaxy spectra at z~1.4 from the DEEP2 redshift survey to show that blueshifted Mg II 2796, 2803 A absorption is ubiquitous in starforming galaxies at this epoch. This is the first detection of frequent outflowing galactic winds at z~1. The presence and depth of absorption are independent of AGN spectral signatures or galaxy morphology; major mergers are not a prerequisite for driving a galactic wind from massive galaxies. Outflows are found in coadded spectra of galaxies spanning a range of 30x in stellar mass and 10x in star formation rate (SFR), calibrated from K-band and from MIPS IR fluxes. The outflows have column densities of order N_H ~ 10^20 cm^-2 and characteristic velocities of ~ 300-500 km/sec, with absorption seen out to 1000 km/sec in the most massive, highest SFR galaxies. The velocities suggest that the outflowing gas can escape into the IGM and that massive galaxies can produce cosmologically and chemically significant outflows. Both the Mg II equivalent width and the outflow velocity are larger for galaxies of higher stellar mass and SFR, with V_wind ~ SFR^0.3, similar to the scaling in low redshift IR-luminous galaxies. The high frequency of outflows in the star-forming galaxy population at z~1 indicates that galactic winds occur in the progenitors of massive spirals as well as those of ellipticals. The increase of outflow velocity with mass and SFR constrains theoretical models of galaxy evolution that include feedback from galactic winds, and may favor momentum-driven models for the wind physics.Comment: Accepted by ApJ. 25 pages, 17 figures. Revised to add discussions of intervening absorbers and AGN-driven outflows; conclusions unchange

Experiences regarding nutrition and exercise among women during early postpartum: A qualitative grounded theory study

Background: Excess gestational weight gain has long- and short-term implications for women and children, and postpartum weight retention is associated with an increased risk of long-term obesity. Despite the existence of dietary and exercise guidelines, many women struggle to return to pre-pregnancy weight. Experiences of women in tackling postpartum weight loss are poorly understood. We undertook this study to explore experiences related to nutrition, exercise and weight in the postpartum in women in Ontario, Canada. Methods: This was a nested qualitative study within The Be Healthy in Pregnancy Study, a randomized controlled trial. Women randomized to the control group were invited to participate. Semi-structured focus groups were conducted at 4-6 months postpartum. Focus groups were audio recorded, transcribed verbatim, coded and analyzed thematically using a constructivist grounded theory approach. Results: Women experienced a complex relationship with their body image, due to unrealistic expectations related to their postpartum body. Participants identified barriers and enablers to healthy habits during pregnancy and postpartum. Gestational weight gain guidelines were regarded as unhelpful and unrealistic. A lack of guidance and information about weight management, healthy eating, and exercise in the postpartum period was highlighted. Conclusion: Strategies for weight management that target the unique characteristics of the postpartum period have been neglected in research and in patient counselling. Postpartum women may begin preparing for their next pregnancy and support during this period could improve their health for subsequent pregnancies

Sloan Digital Sky Survey Imaging of Low Galactic Latitude Fields: Technical Summary and Data Release

The Sloan Digital Sky Survey (SDSS) mosaic camera and telescope have obtained five-band optical-wavelength imaging near the Galactic plane outside of the nominal survey boundaries. These additional data were obtained during commissioning and subsequent testing of the SDSS observing system, and they provide unique wide-area imaging data in regions of high obscuration and star formation, including numerous young stellar objects, Herbig-Haro objects and young star clusters. Because these data are outside the Survey regions in the Galactic caps, they are not part of the standard SDSS data releases. This paper presents imaging data for 832 square degrees of sky (including repeats), in the star-forming regions of Orion, Taurus, and Cygnus. About 470 square degrees are now released to the public, with the remainder to follow at the time of SDSS Data Release 4. The public data in Orion include the star-forming region NGC 2068/NGC 2071/HH24 and a large part of Barnard's loop.Comment: 31 pages, 9 figures (3 missing to save space), accepted by AJ, in press, see http://photo.astro.princeton.edu/oriondatarelease for data and paper with all figure

MicroRNAs in pulmonary arterial remodeling

Pulmonary arterial remodeling is a presently irreversible pathologic hallmark of pulmonary arterial hypertension (PAH). This complex disease involves pathogenic dysregulation of all cell types within the small pulmonary arteries contributing to vascular remodeling leading to intimal lesions, resulting in elevated pulmonary vascular resistance and right heart dysfunction. Mutations within the bone morphogenetic protein receptor 2 gene, leading to dysregulated proliferation of pulmonary artery smooth muscle cells, have been identified as being responsible for heritable PAH. Indeed, the disease is characterized by excessive cellular proliferation and resistance to apoptosis of smooth muscle and endothelial cells. Significant gene dysregulation at the transcriptional and signaling level has been identified. MicroRNAs are small non-coding RNA molecules that negatively regulate gene expression and have the ability to target numerous genes, therefore potentially controlling a host of gene regulatory and signaling pathways. The major role of miRNAs in pulmonary arterial remodeling is still relatively unknown although research data is emerging apace. Modulation of miRNAs represents a possible therapeutic target for altering the remodeling phenotype in the pulmonary vasculature. This review will focus on the role of miRNAs in regulating smooth muscle and endothelial cell phenotypes and their influence on pulmonary remodeling in the setting of PAH