Optically Thin Broad-Line Clouds in Active Galactic Nuclei

The broad-line region (BLR) in Seyfert galaxy nuclei exhibits correlated variations in continuum and emission-line luminosity that are qualitatively consistent with photoionization of ionization-bounded (optically thick) clouds. However, evidence is growing that a nonnegligible fraction of the BLR cloud population is optically thin to the Lyman continuum and fully ionized in hydrogen. We consider the implications of this nebular component for observed line emission and find that inclusion of thin clouds in photoionization calculations can resolve several outstanding puzzles of Seyfert variability, notably the behavior of the C IV λ1549/Lyα ratio as a function of continuum luminosity. A similar population of thin clouds located along our line of sight can account for observed ultraviolet absorption features and \u27warm absorber\u27 behavior at X-ray energies. The Baldwin effect for active galaxies, a negative correlation between ultraviolet emission-line equivalent width and continuum luminosity, can also be explained in detail by a decrease in the covering factor of an optically thin component with increasing source luminosity. The luminosity dependence of covering factor may result from outflows of thin clouds that proceed more efficiently in intrinsically brighter sources. The presence of absorption features in active galactic nuclei (AGNs) that are blueshifted and attain the highest velocities in broad absorption line features associated with luminous QSOs would be consistent with this interpretation

Grazing and No-Till Cropping Impacts on Nitrogen Retention in Dryland Agroecosystems

As the world\u27s population increases, marginal lands such as drylands are likely to become more important for food production. One proven strategy for improving crop production in drylands involves shifting from conventional tillage to no-till to increase water use efficiency, especially when this shift is coupled with more intensive crop rotations. Practices such as no-till that reduce soil disturbance and increase crop residues may promote C and N storage in soil organic matter, thus promoting N retention and reducing N losses. By sampling soils 15 yr after a N tracer addition, this study compared long-term soil N retention across several agricultural management strategies in current and converted shortgrass steppe ecosystems: grazed and ungrazed native grassland, occasionally mowed planted perennial grassland, and three cropping intensities of no-till dryland cropping. We also examined effects of the environmental variables site location and topography on N retention. Overall, the long-term soil N retention of \u3e18% in these managed semiarid ecosystems was high compared with published values for other cropped or grassland ecosystems. Cropping practices strongly influenced long-term N retention, with planted perennial grass systems retaining \u3e90% of N in soil compared with 30% for croplands. Grazing management, topography, and site location had smaller effects on long-term N retention. Estimated 15-yr N losses were low for intact and cropped systems. This work suggests that semiarid perennial grass ecosystems are highly N retentive and that increased intensity of semiarid land management can increase the amount of protein harvested without increasing N losses

Association of circulating ceramides with cardiac structure and function in the community: The Framingham Heart Study

Background A higher circulating plasma ceramide ratio (C16:0/C24:0) is associated with an increased risk of heart failure, even after accounting for standard risk factors including lipid markers. However, the pathobiological mechanisms that underlie this association are incompletely understood. We tested the hypothesis that plasma ceramide ratio (C16:0/C24:0) is associated with adverse cardiac remodeling in the community. Methods and Results We evaluated 2652 Framingham Offspring Study participants (mean age, 66±9 years; 55% women) who attended their eighth examination cycle and underwent routine echocardiography and liquid chromatography-tandem mass spectrometry-based assays for circulating ceramide concentrations. We used multivariable linear regression models to relate C16:0/C24:0 (independent variable) to the following echocardiographic measures (dependent variables; separate models for each): left ventricular mass, left ventricular ejection fraction, left atrial emptying fraction, left atrial end-systolic volume, E/e\u27 (a measure of left ventricular diastolic function), and left ventricular global circumferential and longitudinal strain by speckle-tracking echocardiography. In multivariable-adjusted analyses, higher C16:0/C24:0 per standard deviation increment was associated with lower left ventricular ejection fraction (0.991-fold change in left ventricular ejection fraction

Milestones: a Rapid Assessment Method for the Clinical Competency Committee

INTRODUCTION: Educational milestones are now used to assess the developmental progress of all U.S. graduate medical residents during training. Twice annually, each program\u27s Clinical Competency Committee (CCC) makes these determinations and reports its findings to the Accreditation Council for Graduate Medical Education (ACGME). The ideal way to conduct the CCC is not known. After finding that deliberations reliant upon the new milestones were time intensive, our internal medicine residency program tested an approach designed to produce rapid but accurate assessments. MATERIAL AND METHODS: For this study, we modified our usual CCC process to include pre-meeting faculty ratings of resident milestones progress with in-meeting reconciliation of their ratings. Data were considered largely via standard report and presented in a pre-arranged pattern. Participants were surveyed regarding their perceptions of data management strategies and use of milestones. Reliability of competence assessments was estimated by comparing pre-/post-intervention class rank lists produced by individual committee members with a master class rank list produced by the collective CCC after full deliberation. RESULTS: Use of the study CCC approach reduced committee deliberation time from 25 min to 9 min per resident (p \u3c 0.001). Committee members believed milestones improved their ability to identify and assess expected elements of competency development (p = 0.026). Individual committee member assessments of trainee progress agreed well with collective CCC assessments. CONCLUSIONS: Modification of the clinical competency process to include pre-meeting competence ratings with in-meeting reconciliation of these ratings led to shorter deliberation times, improved evaluator satisfaction and resulted in reliable milestone assessments

The Black Hole Mass of NGC 4151: Comparison of Reverberation Mapping and Stellar Dynamical Measurements

We present a stellar dynamical estimate of the black hole (BH) mass in the Seyfert 1 galaxy, NGC 4151. We analyze ground-based spectroscopy as well as imaging data from the ground and space, and we construct 3-integral axisymmetric models in order to constrain the BH mass and mass-to-light ratio. The dynamical models depend on the assumed inclination of the kinematic symmetry axis of the stellar bulge. In the case where the bulge is assumed to be viewed edge-on, the kinematical data give only an upper limit to the mass of the BH of ~4e7 M_sun (1 sigma). If the bulge kinematic axis is assumed to have the same inclination as the symmetry axis of the large-scale galaxy disk (i.e., 23 degrees relative to the line of sight), a best-fit dynamical mass between 4-5e7 M_sun is obtained. However, because of the poor quality of the fit when the bulge is assumed to be inclined (as determined by the noisiness of the chi^2 surface and its minimum value), and because we lack spectroscopic data that clearly resolves the BH sphere of influence, we consider our measurements to be tentative estimates of the dynamical BH mass. With this preliminary result, NGC 4151 is now among the small sample of galaxies in which the BH mass has been constrained from two independent techniques, and the mass values we find for both bulge inclinations are in reasonable agreement with the recent estimate from reverberation mapping (4.57[+0.57/-0.47]e7 M_sun) published by Bentz et al.Comment: 20 pages, including 11 low-res figures. Accepted for publication in ApJ. High resolution version available upon reques

The Geometry and Kinematics of the Broad-Line Region in NGC 5548 from HST and IUE Observations

The spatial and radial velocity distribution of broad-line-emitting gas in the Seyfert 1 galaxy NGC 5548 is examined through the process of reverberation mapping, which is done by detailed comparison of continuum and emission-line variations. Recent spectroscopic monitoring of NGC 5548 with HST and IUE allows us to resolve the transfer function (TF) that relates the continuum and emission-line variability. We also examine the radial velocity-resolved TFs, and confirm that predominantly radial motions of the line-emitting clouds can be excluded. We find that a broad-line region comprised of clouds that are orbiting a central source of mass ~108 M☉ along randomly inclined Keplerian orbits and irradiated by a beamed continuum source yields a TF and line profile that are qualitatively consistent with the observations. In this model, the clouds that produce the variable C IV emission lie within 12 lt-days of the central source, and the continuum radiation is confined to a wide biconical beam (semi-opening angle 35°-60°) with the observer viewing into the cone

Novel biofortified sorghum lines with combined waxy (high amylopectin) starch and high protein digestibility traits : effects on endosperm and flour properties

Novel biofortified sorghum lines have been developed with both waxy starch (high amylopectin) and high protein digestibility traits. Eight sorghum lines with different combinations of waxy, non-waxy, high- and normal-protein digestibility traits were studied in relation to flour properties. Lines with the high protein digestibility trait had loosely packed starch granules and floury endosperm, irrespective of whether they were waxy or non-waxy. In terms of thermal properties, combined waxy-high digestibility lines had the highest onset endothermic temperature as well as endothermic energy compared to non-waxy, normal protein digestibility lines. The waxy-high protein digestibility lines had higher paste viscosity and formed much softer and less sticky pastes than the non-waxy, normal protein digestibility lines. Flours of the combined waxy-high protein digestibility sorghum lines had much higher solubility than the non-waxy- normal protein digestibility lines. At 30 C flour solubility, waxy-high protein digestibility sorghum lines flour was similar to commercial wheat bread flours. The high flour solubility, high pasting viscosity and soft paste of sorghum lines with combined waxy and high protein digestibility traits indicate that their flours may have better properties for making dough-based food products than normal non-waxy, normal protein digestibility sorghums.Howard G. Buffett Foundation through the Norman E. Borlaug Institute for International Agriculture of Texas A&M AgriLife Research and by the US- Department of Transportation Subgrant 2011. University of Pretoria Research Support Bursary.http://www.elsevier.com/locate/jcs2016-09-30hb2016Food Scienc