3,043 research outputs found

    Stabilized Lanthanum Sulphur Compounds

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    Lanthanum sulfide is maintained in the stable cubic phase form over a temperature range of from 500 C to 1500 C by adding to it small amounts of calcium, barium. or strontium. This novel compound is an excellent thermoelectric material

    Physician and Patient Moves in the Hospital Do Not Move Patient Satisfaction: A Single-Center Retrospective Analysis

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    Background. Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) is a standardized survey for measuring patient\u27s experiences at US hospitals. There is a shift towards geographically assigning patients and physicians. However, its impact on patient satisfaction scores has not been studied. Objective: Examine the correlation between patient experience and overall hospital rating with the number of physicians seen and the number of times the patient was moved during a hospitalization. Methods: A retrospective observational study was performed using select HCAHPS & Press Ganey survey questions to assess physician satisfaction scores and overall hospital rating and recommendation scores. Results: There was no significant difference across the select survey questions based on the number of times a patient was moved or the hospitalists seen during a hospitalization on most questions. A higher case mix index was associated with an increased likelihood of receiving the highest rating for the hospital (OR 1.39,95% CI 1.03-1.88), p 0.03), and two other physician communication questions. An increase in the length of stay was associated with a lower likelihood of receiving the highest rating for similar physician communication questions (OR 0.91, 95% CI 0.83 to 0.99,p 0.04) Conclusions: The number of hospitalists seen by the patient and the number of times a patient is moved during a hospitalization is not associated with physicians related patient satisfaction scores, overall care received in the hospital, or if the patient would recommend the hospital to others

    On The Reddening in X-ray Absorbed Seyfert 1 Galaxies

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    There are several Seyfert galaxies for which there is a discrepancy between the small column of neutral hydrogen deduced from X-ray observations and the much greater column derived from the reddening of the optical/UV emission lines and continuum. The standard paradigm has the dust within the highly ionized gas which produces O~VII and O~VIII absorption edges (i.e., a ``dusty warm absorber''). We present an alternative model in which the dust exists in a component of gas in which hydrogen has been stripped, but which is at too low an ionization state to possess significant columns of O~VII and O~VIII (i.e, a ``lukewarm absorber''). The lukewarm absorber is at sufficient radial distance to encompass much of the narrow emission-line region, and thus accounts for the narrow-line reddening, unlike the dusty warm absorber. We test the model by using a combination of photoionization models and absorption edge fits to analyze the combined ROSAT/ASCA dataset for the Seyfert 1.5 galaxy, NGC 3227. We show that the data are well fit by a combination of the lukewarm absorber and a more highly ionized component similar to that suggested in earlier studies. We predict that the lukewarm absorber will produce strong UV absorption lines of N V, C IV, Si IV and Mg II. Finally, these results illustrate that singly ionized helium is an important, and often overlooked, source of opacity in the soft X-ray band (100 - 500 eV).Comment: 17 pages, Latex, includes 1 figure (encapsulated postscript), one additional table in Latex (landscape format), to appear in the Astrophysical Journa

    Evaluation of Wastewater Filtration

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    Tertiary filtration of secondary wastewater is frequently used to improve wastewater treatment plant effluent quality. Four experimental filter columns were operated at the Preston, Idaho, Wastewater Treatment Plant to evaluate the effectiveness of granular media, gravity filtration. The Preston plant is a trickling filter secondary treatment plant and services a population of approximately 3600 people. Four filter medium configurations were studied. Multi-media, dual-media, and single-media beds were constructed with the following media configurations: (1) coal-sand-garnet; (2) coal-sand; (3) sand-garnet; and (4) all sand. The filters were operated at two hydraulic loading rates. Effluents from the primary clarifier, trickling filter, and secondary clarifier were filtered to compare the difference in filter operation and performance when filtering different effluents. Wastewater quality parameters used to monitor filter performance were biochemical oxygen demand (BOD5) and suspended solids. The quality of filter influend affected the quality of the filter effluent. Typical total BOD5 and suspended soilds removal efficiencies were 30 percent and 75 percent, respectively. Soluble BOD5 was not significantly removed by granular filtration. The four filter beds were equally effective in removing suspended solids and biochemical oxygen demand. The coal layered filters operated for 22 hours maximum. The longest filter run time for the sand filters was 9 hours. Filtration of the Preston treatment facility effluent did not consistently produce and effluent that would satisfy the 10 mg/l BOD5 effluent discharge requirement. A survey conducted to review approbal criteria and design standards for wastewater filters employed by state regulatory agencies indicated the following. Most state standards allowed the installation of either gravity flow filters or pressure filters. The majority of state agencies base the allowable hydraulic loading rate on the type and configuration of media employed. The majority of the design standards for wastewater filters permitted the following media types: (1) sand; (2) anthracite; (3) sand and anthracite; (4) sand, anthracite, and garnet or ilmenite. All wastewater filter design standards called for backwast appurtenances complete with air scour or mechanical scour

    Economic inequalities in the effectiveness of a primary care intervention for depression and suicidal ideation.

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    BACKGROUND: Economic disadvantage is associated with depression and suicide. We sought to determine whether economic disadvantage reduces the effectiveness of depression treatments received in primary care. METHODS: We conducted differential-effects analyses of the Prevention of Suicide in Primary Care Elderly: Collaborative Trial, a primary-care-based randomized, controlled trial for late-life depression and suicidal ideation conducted between 1999 and 2001, which included 514 patients with major depression or clinically significant minor depression. RESULTS: The intervention effect, defined as change in depressive symptoms from baseline, was stronger among persons reporting financial strain at baseline (differential effect size = -4.5 Hamilton Depression Rating Scale points across the study period [95% confidence interval = -8.6 to -0.3]). We found similar evidence for effect modification by neighborhood poverty, although the intervention effect weakened after the initial 4 months of the trial for participants residing in poor neighborhoods. There was no evidence of substantial differences in the effectiveness of the intervention on suicidal ideation and depression remission by economic disadvantage. CONCLUSIONS: Economic conditions moderated the effectiveness of primary-care-based treatment for late-life depression. Financially strained individuals benefited more from the intervention; we speculate this was because of the enhanced treatment management protocol, which led to a greater improvement in the care received by these persons. People living in poor neighborhoods experienced only temporary benefit from the intervention. Thus, multiple aspects of economic disadvantage affect depression treatment outcomes; additional work is needed to understand the underlying mechanisms

    Variable UV Absorption in the Seyfert 1.5 Galaxy NGC 3516: The Case for Associated UV and X-ray Absorption

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    We present observations of the UV absorption lines in the Seyfert 1 galaxy NGC 3516, obtained at a resolution of λ\lambda/Δλ\Delta\lambda ≈\approx 40,000 with the Space Telescope Imaging Spectrograph (STIS) on 2000 October 1. The UV continuum was ∼\sim4 times lower than that observed during 1995 with the Goddard High Resolution Spectrograph (GHRS), and the X-ray flux from a contemporaneous {\it Chandra X-ray Observatory (CXO)} observation was a factor of ∼\sim8 below that observed with {\it ASCA}. The STIS spectra show kinematic components of absorption in Lyα\alpha, C IV, and N V at radial velocities of -376, -183, and -36 km s−1^{-1} (components 1, 2, and 3+4, respectively), which were detected in the earlier GHRS spectra; the last of these is a blend of two GHRS components that have increased greatly in column density. Four additional absorption components have appeared in the STIS spectra at radial velocities of -692, -837, -994, and -1372 km s−1^{-1} (components 5 through 8); these may also have been present in earlier low-flux states observed by the {\it International Ultraviolet Explorer (IUE)}. Based on photoionization models, we suggest that the components are arranged in increasing radial distance in the order, 3+4, 2, 1, followed by components 5 -- 8. We have achieved an acceptable fit to the X-ray data using the combined X-ray opacity of the UV components 1, 2 and 3+4. By increasing the UV and X-ray fluxes of these models to match the previous high states, we are able to match the GHRS C IV column densities, absence of detectable C IV absorption in components 5 through 8, and the 1994 {\it ASCA} spectrum. We conclude that variability of the UV and X-ray absorption in NGC 3516 is primarily due to changes in the ionizing flux.Comment: 7 figures (note that Fig6 is not referenced in the .Tex file and must be printed separately). There are 6 tables in the .tex file and an additional 8 tables included as separate .ps files. Accepted for Publication in the Astrophysical Journa

    The Kinematics and Physical Conditions pf the Ionized Gas in Markarian 509. II. STIS Echelle Observations

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    We present observations of the UV absorption lines in the luminous Seyfert 1 galaxy Mrk 509, obtained with the medium resolution (lambda/Delta-lambda ~ 40,000) echelle gratings of the Space Telescope Imaging Spectrograph on the Hubble Space Telescope. The spectra reveal the presence of eight kinematic components of absorption in Ly-alpha, C IV, and N V, at radial velocities of -422, -328, -259, -62, -22, +34, +124, and +210 km s^-1 with respect to an emission-line redshift of z = 0.03440, seven of which were detected in an earlier Far Ultraviolet Spectrographic Explorer (FUSE) spectrum. The component at -22 km s^-1 also shows absorption by Si IV. The covering factor and velocity width of the Si IV lines were lower than those of the higher ionization lines for this component, which is evidence for two separate absorbers at this velocity. We have calculated photoionization models to match the UV column densities in each of these components. Using the predicted O VI column densities, we were able to match the O VI profiles observed in the FUSE spectrum. Based on our results, none of the UV absorbers can produce the X-ray absorption seen in simultaneous Chandra observations; therefore, there must be more highly ionized gas in the radial velocity ranges covered by the UV absorbers.Comment: 30 pages, three figures (Figure 1 is in color). Accepted for publication in the Astrophysical Journa

    Ionized Absorbers in AGN: the Role of Collisional Ionization and Time-Evolving Photoionization

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    In this paper we explore collisional ionization and time-evolving photoionization in the, X-ray discovered, ionized absorbers in Seyfert galaxies. These absorbers show temporal changes inconsistent with simple equilibrium models. We develop a simple code to follow the temporal evolution of non-equilibrium photoionized gas. As a result several effects appear that are easily observable; and which, in fact, may explain otherwise paradoxical behavior. Specifically we find that: 1) In many important astrophysical conditions pure collisional and photoionization equilibria can be distinguished with moderate spectral resolution observations, due to a strong absorption structure between 1 and 3 keV. 2) In time-evolving non-equilibrium photoionization models the response of the ionization state of the gas to sudden changes of the ionizing continuum is smoothed and delayed at low gas densities, even when the luminosity increases. 3) If the changes of the ionizing luminosity are not instantaneous, and the electron density is low enough (the limit depends on the average ionization state of the gas), the ionization state of the gas can continue to increase while the source luminosity decreases, so a maximum in the ionization state of a given element may occur during a minimum of the ionizing intensity (the opposite of the prediction of equilibrium models). 4) Different ions of different elements reach their equilibrium configuration on different time-scales. These properties are similar to those seen in several ionized absorbers in AGN, properties which had hitherto been puzzling. We applied these models to a high S/N ROSAT PSPC observation of the Seyfert 1 galaxy NGC 4051.Comment: 36 pages, 10 figures, accepted for publication on Apj, in pres

    X-ray Observations of the Seyfert galaxy LB 1727 (1H 0419-577)

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    We discuss the properties of the Seyfert 1.5 galaxy LB 1727, also known as 1H 0419-577, from X-ray observations obtained by ASCA and ROSAT along with optical observations from earlier epochs. ASCA shows only modest (< 20%) variations in X-ray flux within or between the observations. In contrast, a daily monitoring campaign over 1996 Jun - Sept by the ROSAT HRI instrument reveals the soft X-ray (0.1-2 keV) flux to have increased by a factor ~3. The 2 - 10 keV continuum can be parameterized as a power-law with a photon index Gamma ~ 1.45-1.68 across ~0.7 - 11 keV in the rest-frame. We also report the first detection of iron Kalpha line emission in this source. Simultaneous ASCA and ROSAT data show the X-ray spectrum to steepen sharply at a rest-energy \~0.75 keV, the spectrum below this energy can be parameterized as a power-law of slope Gamma ~3.6. We show that LB 1727 is one of the few Seyferts for which we can rule out the possibility that the presence of a warm absorber is solely responsible for the spectral steepening in the soft X-ray regime. Consideration of the overall spectral-energy-distribution for this source indicates the presence of a pronounced XUV-bump visible in optical, ultraviolet and soft X-ray data.Comment: 27 pages, 7 figures. LaTeX with encapsulated postscript. To appear in the Astrophysical Journa
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