5,756 research outputs found

    Locally Optimally-emitting Clouds and the Narrow Emission Lines in Seyfert Galaxies

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    The narrow emission line spectra of active galactic nuclei are not accurately described by simple photoionization models of single clouds. Recent Hubble Space Telescope images of Seyfert 2 galaxies show that these objects are rich with ionization cones, knots, filaments, and strands of ionized gas. Here we extend to the narrow line region the ``locally optimally emitting cloud'' (LOC) model, in which the observed spectra are predominantly determined by powerful selection effects. We present a large grid of photoionization models covering a wide range of physical conditions and show the optimal conditions for producing many of the strongest emission lines. We show that the integrated narrow line spectrum can be predicted by an integration of an ensemble of clouds, and we present these results in the form of diagnostic line ratio diagrams making comparisons with observations. We also predict key diagnostic line ratios as a function of distance from the ionizing source, and compare these to observations. The predicted radial dependence of the [O III]/[O II] ratio may be matched to the observed one in NGC4151, if the narrow line clouds see a more intense continuum than we see. The LOC scenario when coupled with a simple Keplerian gravitational velocity field will quite naturally predict the observed line width versus critical density relationship. The influence of dust within the ionized portion of the clouds is discussed and we show that the more neutral gas is likely to be dusty, although a high ionization dust-free region is most likely present too. This argues for a variety of NLR cloud origins.Comment: 29 pages plus 16 figures, accepted for publication in Ap

    Severity of COPD at initial spirometry-confirmed diagnosis: data from medical charts and administrative claims

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    PurposeThis study was conducted to determine COPD severity at the time of diagnosis as confirmed by spirometry in patients treated in a US managed care setting.Patients and methodsAll patients with one or more inpatient stays, one or more emergency department visits, or two or more outpatient visits with diagnosis codes for COPD during 1994–2006 were identified from the Lovelace Patient Database. From this group, a subset of continuously enrolled patients with evidence in claims of a first available pulmonary function test or pulmonary clinic visit and a confirmatory claim for a COPD diagnosis was selected. Medical chart abstraction was undertaken for this subset to gather information for diagnosis and severity staging of each patient based on the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria for COPD.ResultsOf the 12,491 patients with a primary or secondary COPD diagnosis between 1994 and 2006, there were 1520 continuously enrolled patients who comprised the study cohort. Among the 648 eligible records from patients with evidence of a pulmonary function test, 366 were identified by spirometry as having COPD of GOLD stage I or higher (average percentage of predicted forced expiratory volume in 1 second: 60%): 19% were diagnosed at the stage of mild disease (GOLD stage I); 50% at moderate disease (GOLD stage II); and 31% at severe or very severe disease (GOLD stage III or IV, respectively). The majority of patients in these groups were not receiving maintenance treatment.ConclusionThe results demonstrate a very low incidence of early-stage diagnosis, confirmed by a pulmonary function test, of COPD in a large US sample and support calls for increased screening for COPD and treatment upon diagnosis

    He II Reverberation in Active Galactic Nucleus Spectra

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    This paper compares the observed reverberation response lags and the intensity ratios of the broad-line region (BLR) emission lines He II λ1640, He II λ4686, and C IV λ1549 with predictions. Published observations indicate that the He II λ1640 lag is 3 times shorter than the lags of He II λ4686 or C IV λ1549. Diverse models, however, do not reproduce this observation. Extensive improved numerical simulations of the hydrogenic isoelectronic sequence emission show that the He II spectrum remains especially simple, even in the central regions of a luminous quasar. Line trapping never builds up a significant population of excited states, and the emissivities of the two He II lines are close to simple case B predictions. Using improved He II calculations, we computed the lags of distributions of clouds concentrated in approximate radius-dependent pressure laws as well as the lags of locally optimally emitting cloud (LOC) distributions. In addition, the effect on lags and intensities due to anisotropic beaming of line emission and observer orientation angle with respect to an obscuring disk is estimated. Comparing our results to observations, we do not see how any distribution of clouds can produce intrinsic He II λ1640 and He II λ4686 emission with substantially different responses, nor do we see how He II λ1640 can vary on a substantially shorter timescale than C IV λ1549. Our models suggest that in fact the observed He II λ1640 reverberation timescale is shorter than expected rather than the observed He II λ4686 timescale being longer than expected. We discuss a possible explanation

    Effects of Artificial Ultraviolet Light Exposure on Reproductive Success of the Female Panther Chameleon (Furcifer pardalis) in Captivity

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    Having previously documented experimentally the need for ultraviolet B (UVB) irradiation (290-315 nm) in the light environment of captive female panther chameleons (Furcifer pardalis) to ensure hatching success of their eggs, we investigated optimal UVB irradiation levels. From 1996-1998 28 hatchling female panther chameleons were raised to maturity and bred (using vitamin and mineralfortified insect diets low in vitamin D) in nine different artificial UVB light environments. Seven of the environments included long (12 hr/day) low irradiation exposures ranging from 1.7 to 22 mW/cm 2 UVB, with a corresponding conversion of provitamin D 3 to photoproducts in in vitro models of 0.18 to 1.52% in 2 hr. Two environments included short (0.5 and 1.0 hr/day), high irradiation exposures of 55 and 49 mW/cm 2 UVB, respectively, with a corresponding conversion of provitamin D 3 to photoproducts in in vitro models of 8.3% to 14.6% in the respective 0.5-and 1.0-hr time periods. Females raised with the mid-level long/low exposures (5-15 mW/cm 2 UVB; 0.52-1.32% conversion to photoproducts in in vitro models) produced viable eggs with a significantly higher percentage of hatching compared to those with the extreme (highest or lowest) long/low exposures. Those raised with the short-/high-exposure environments produced viable eggs with a generally high percentage of hatching, but success was variable. The results and techniques for light quality assessment are interpreted, with recommendations for practical application by the *Correspondence to

    Numerical Simulations of Fe II Emission Spectra

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    This paper describes the techniques that we have used to incorporate a large-scale model of the Fe+ ion and resulting Fe IIemission into CLOUDY, a spectral synthesis code designed to simulate conditions within a plasma and model the resulting spectrum. We describe the numerical methods we use to determine the level populations, mutual line overlap fluorescence, collisional effects, and the heating-cooling effects of the atom on its environment. As currently implemented, the atom includes the lowest 371 levels (up to 11.6 eV) and predicts intensities of 68,635 lines. We describe our data sources, which include the most recent transition probabilities and collision strengths. Although we use detailed fits to temperature-dependent collision strengths where possible, in many cases the uncertain g approximation is the only source for collision data. The atom is designed to be readily expanded to include more levels and to incorporate more accurate sets of collision and radiative data as computers grow faster and the atomic databases expand. We present several test cases showing that the atom goes to LTE in the limits of high particle and radiation densities. We give an overview of general features of the Fe II spectra as their dependencies on the basic parameters of our models (density, flux, microturbulent velocity, the Fe abundance, and Lyα pumping). Finally, we discuss several applications to active galactic nuclei to illustrate the diagnostic power of the Fe II spectrum and make some predictions for UV observations

    High-Yielding Corn Response to Applied Phosphorus, Potassium, and Sulfur in Nebraska

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    Nutrient management recommendations may change as yield levels and efficiency of crop production increase. Recommendations for P, K, and S were evaluated using results from 34 irrigated corn (Zea mays L.) trials conducted in diverse situations across Nebraska. The mean yield was 14.7 Mg ha-1 with adequate fertilizer applied. Th e median harvest index values were 0.52, 0.89, 0.15, and 0.56 for biomass, P, K, and S, respectively. Median grain yields were 372, 49, and 613 kg kg-1 of above-ground plant uptake of P, K, and S, respectively. The estimated critical Bray-1 P level for corn response to 20 kg P ha-1 was 20 mg kg-1 when the previous crop was corn compared with 10 mg kg-1 when corn followed soybean [Glycine max (L.) Merr.]. Soil test K was generally high with only three site-years kg-1. Over all trials, application of 40 kg K ha-1 resulted in a 0.2 Mg ha-1 mean grain yield decrease. Application of 22 kg S ha-1 did not result in significant yield increase in any trial. Soil test results accounted for twice as much variation in nutrient uptake when soil organic matter (SOM) and pH were considered in addition to the soil test nutrient values. The results indicate a need to revise the current recommendation for P, to maintain the current K and S recommendations, and to use SOM and pH in addition to soil test nutrient values in estimating applied nutrient requirements for irrigated high yield corn production

    High-Yielding Corn Response to Applied Phosphorus, Potassium, and Sulfur in Nebraska

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    Nutrient management recommendations may change as yield levels and efficiency of crop production increase. Recommendations for P, K, and S were evaluated using results from 34 irrigated corn (Zea mays L.) trials conducted in diverse situations across Nebraska. The mean yield was 14.7 Mg ha-1 with adequate fertilizer applied. Th e median harvest index values were 0.52, 0.89, 0.15, and 0.56 for biomass, P, K, and S, respectively. Median grain yields were 372, 49, and 613 kg kg-1 of above-ground plant uptake of P, K, and S, respectively. The estimated critical Bray-1 P level for corn response to 20 kg P ha-1 was 20 mg kg-1 when the previous crop was corn compared with 10 mg kg-1 when corn followed soybean [Glycine max (L.) Merr.]. Soil test K was generally high with only three site-years kg-1. Over all trials, application of 40 kg K ha-1 resulted in a 0.2 Mg ha-1 mean grain yield decrease. Application of 22 kg S ha-1 did not result in significant yield increase in any trial. Soil test results accounted for twice as much variation in nutrient uptake when soil organic matter (SOM) and pH were considered in addition to the soil test nutrient values. The results indicate a need to revise the current recommendation for P, to maintain the current K and S recommendations, and to use SOM and pH in addition to soil test nutrient values in estimating applied nutrient requirements for irrigated high yield corn production

    Tiotropium/Olodaterol Delays Clinically Important Deterioration Compared with Tiotropium Monotherapy in Patients with Early COPD:a Post Hoc Analysis of the TONADO® Trials

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    Introduction Since chronic obstructive pulmonary disease (COPD) is a heterogeneous condition, a composite endpoint of clinically important deterioration (CID) may provide a more holistic assessment of treatment efficacy. We compared long-acting muscarinic antagonist/long-acting beta(2)-agonist combination therapy with tiotropium/olodaterol versus tiotropium alone using a composite endpoint for CID. CID was evaluated overall and in patients with low exacerbation history (at most one moderate exacerbation in the past year [not leading to hospitalisation]), Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2 patients and maintenance-naive patients with COPD. We assessed whether early treatment optimisation is more effective with tiotropium/olodaterol versus tiotropium in delaying and reducing the risk of CID. Methods Data were analysed from 2055 patients treated with either tiotropium/olodaterol 5/5 mu g or tiotropium 5 mu g (delivered via Respimat(R)) in two replicate, 52-week, parallel-group, double-blind studies (TONADO(R) 1/2). CID was defined as a decline of at least 0.1 L from baseline in trough forced expiratory volume in 1 s, increase from baseline of at least 4 units in St. George's Respiratory Questionnaire score, or moderate/severe exacerbation. Time to first occurrence of one of these events was recorded as time to first CID. Results Overall, treatment with tiotropium/olodaterol significantly increased the time to, and reduced the risk of, CID versus tiotropium (median time to CID 226 versus 169 days; hazard ratio [HR] 0.76 [95% confidence interval 0.68, 0.85]; P <0.0001). Significant reductions were also observed in patients with low exacerbation history (241 versus 170; HR 0.73 [0.64, 0.83]; P <0.0001), GOLD 2 patients (241 versus 169; 0.72 [0.61, 0.84]; P <0.0001) and maintenance-naive patients (233 versus 171; 0.75 [0.62, 0.91]; P = 0.0030). Conclusion In patients with COPD, including patients with low exacerbation history, GOLD 2 patients and maintenance-naive patients, tiotropium/olodaterol reduced the risk of CID versus tiotropium. These results demonstrate the advantages of treatment optimisation with tiotropium/olodaterol over tiotropium monotherapy. PLAIN LANGUAGE SUMMARY COPD is a complicated disease that deteriorates over time. Worsening of COPD is associated with the lungs working less effectively, a fall in quality of life and a rise in sudden flare-ups of the disease. In this study, we looked at lung function, quality of life and flare-ups together using a measure called "clinically important deterioration" (CID). We looked at 2055 people with COPD to compare the effects of taking two bronchodilators (tiotropium and olodaterol) against taking one bronchodilator (tiotropium alone). Bronchodilators are a type of inhaled medication that relax the muscles in the lungs and widen airways, making it easier to breathe. They have also been shown to reduce sudden flare-ups of COPD. Across a wide range of people with COPD, we found that treatment with tiotropium/olodaterol reduced the risk of a CID compared with tiotropium alone. This includes in those patients at an early stage of disease, who may benefit from finding the best treatment option for them as early as possible

    Efficacy of salmeterol/fluticasone propionate by GOLD stage of chronic obstructive pulmonary disease: analysis from the randomised, placebo-controlled TORCH study

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    Background: The efficacy of inhaled salmeterol plus fluticasone propionate (SFC) in patients with severe or very severe COPD is well documented. However, there are only limited data about the influence of GOLD severity staging on the effectiveness of SFC, particularly in patients with milder disease. Methods: TORCH was a 3-year, double-blind, placebo-controlled trial of 6112 patients with moderate/severe COPD with pre-bronchodilator FEV1 < 60% predicted (mean age 65 years, 76% male, mean 44% predicted FEV1, 43% current smokers). To understand the relative efficacy of SFC and its components by GOLD stages, we conducted a post-hoc analysis of the TORCH dataset using baseline post-bronchodilator FEV1 to segment patients into three groups: moderate COPD (GOLD stage II and above: ³ 50%; n = 2156), severe COPD (GOLD stage III: 30% to < 50%; n = 3019) and very severe COPD (GOLD stage IV: < 30%; n = 937). Results: Compared with placebo, SFC improved post-bronchodilator FEV1: 101 ml (95% confidence interval [CI]: 71, 132) in GOLD stage II, 82 ml (95% CI: 60, 104) in GOLD stage III and 96 ml (95% CI: 54, 138) in GOLD stage IV patients, and reduced the rate of exacerbations: 31% (95% CI: 19, 40) in GOLD stage II, 26% (95% CI: 17, 34) in GOLD stage III and 14% (95% CI: -4,29) in GOLD stage IV. SFC improved health status to a greater extent than other treatments regardless of baseline GOLD stage. Similarly, SFC reduced the risk of death by 33% (hazard ratio [HR] 0.67; 95% CI: 0.45, 0.98) for GOLD stage II, 5% (HR 0.95; 95% CI: 0.73, 1.24) for GOLD stage III, and 30% (HR 0.70; 95% CI: 0.47, 1.05) for GOLD stage IV. The rates of adverse events were similar across treatment arms and increased with disease severity. Overall, there was a higher incidence of pneumonia in the fluticasone propionate and SFC arms, compared with other treatments in all GOLD stages. Conclusion: In the TORCH study, SFC reduced moderate-to-severe exacerbations and improved health status and FEV1 across GOLD stages. Treatment with SFC may be associated with reduced mortality compared with placebo in patients with GOLD stage II disease. The effects were similar to those reported for the study as a whole. Thus, SFC is an effective treatment option for patients with GOLD stage II COPD
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