461 research outputs found

    Long-Term Profile Variability of Double-Peaked Emmission Lines in AGNs

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    An increasing number of AGNs exhibit broad, double-peaked Balmer emission lines, which arise from the outer regions of the accretion disk which fuels the AGN. The line profiles vary on timescales of 5--10 years. Our group has monitored a set of 20 double-peaked emitters for the past 8 years (longer for some objects). Here we describe a project to characterize the variability patterns of the double-peaked H alpha line profiles and compare with those of two simple models: a circular disk with a spiral arm and an elliptical disk.Comment: 2 pages, 1 figure, to appear in the proceedings of "The Interplay among Black Holes, Stars and ISM in Galactic Nuclei", IAU 222, eds. T. Storchi Bergmann, L.C. Ho, and H.R. Schmit

    Clinical management of smoking cessation: patient factors affecting a reward-based approach

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    Although the majority of current smokers indicate they would like to quit, only about half of smokers make a quit attempt each year. Of those who attempt to quit, only about 5% are successful. Many effective products and programs are available to assist in smoking cessation; however those interested in quitting often do not make use of these resources. To increase use of cessation products in order to improve successful cessation rates, the Consumer Demand Roundtable has argued that smokers need to be viewed as consumers of cessation products rather than as patients needing treatment. With this consumer-based approach in mind, the current review examines how participant characteristics, perceptions, and behavior influence, and are influenced by, contingency management (CM) paradigms in various settings. Findings suggest that participant factors associated with success in these programs include demographic characteristics (eg, gender, marital status), self-efficacy, motivation to quit, and impulsivity. Overall, participants perceive incentives for successful cessation as motivating. However, such programs may involve greater withdrawal symptoms (eg, craving for cigarettes) initially, but these symptoms tend to decrease at a greater rate over time compared with nonincentive group participants. CM programs have also been shown to be successful across a number of settings (eg, communities, schools), including settings in which smokers are often considered difficult to treat (eg, substance abuse treatment centers). Overall, CM programs are perceived positively by participants and can increase rates of successful cessation. Furthermore, CM interventions have the flexibility to adapt to individual preferences and needs, leading to greater participation and likelihood of successful cessation. Thus, CM provides an important framework for addressing the need for consumer-focused smoking cessation interventions

    Human nonspecific suppressive lymphokines

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    Since the term “lymphokine” first appeared in print over 20 years ago, a tremendous number of these soluble mediators of the immune system have been described. Within the past few years, many human nonspecific suppressive lymphokines have been identified. This review discusses the historical basis of immunologic suppression and suppressor factors. Later reports describing suppressive human lymphokines are then grouped into four categories: primarily stimulatory lymphokines that also mediate certain suppressive activities, suppressive lymphokines produced during altered states of immunity, suppressive lymphokines produced by exogenously stimulated lymphocytes, and suppressive lymphokines produced by unstimulated lymphocytes. Recent work I have been involved in focusing on the human suppressive lymphokine soluble suppressor factor (SSF) is also discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44842/1/10875_2004_Article_BF00918789.pd

    Multihospital System Affiliation as a Survival Strategy for Rural Hospitals Under the Prospective Payment System

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    The introduction of Medicare's Prospective Payment System (PPS) has disproportionately increased financial pressures on rural hospitals and posed challenges to the survival of these institutions. Increasingly, rural hospitals are seeking strategies that can enhance their chances for survival in a turbulent and hostile environment. This study examined the survival effects of one such strategy, multihospital system affiliation. Specifically, we assessed: (1) whether and how different types of system affiliation in the post-PPS era affect the likelihood of rural hospital survival; (2) whether particular structural, environmental and hospital performance characteristics moderate the effects of system affiliation on rural hospital survival; and (3) whether systematic selection by rural hospitals into multihospital systems potentially accounts for observed relationships between system affiliation and survival. Proportional hazards analyses indicate that system affiliation with investor-owned systems significantly reduces survival probabilities of rural hospitals. Affiliation with not-for-profit systems or system affiliation under contract management arrangements does not affect survival probabilities of rural hospitals. These general findings are moderated by the effects of hospital ownership and size at the time of affiliation. Finally, study findings indicated that systematic selection by poor performing rural hospitals into investor-owned systems has occurred in the post-PPS era. No evidence of selection into not-for-profit systems was discovered.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73618/1/j.1748-0361.1992.tb00334.x.pd

    Motivations for smoking cessation: A comparison of successful quitters and failures

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    To foster successful smoking cessation, public health professionals need to understand better the reasons why smokers quit smoking. Although researchers have studied smokers' characteristics that may predict smoking cessation, few studies have examined the relationships between reasons stated for quitting and successful smoking cessation.We examined six reasons for smoking cessation and their association with successfully quitting among approximately 7,700 current and former smokers who participated in the 1986 Adult Use of Tobacco Survey (AUTS). Using logistic regression analysis, we found that successful cessation was associated with having personal concerns regarding the health effects of smoking and with wanting to set a good example for children. In contrast, concerns about the cost of smoking, the effect of smoking on others, and pressure from friends and family to quit were associated with decreased likelihoods of cessation. Furthermore, the relative importance of a reason (somewhat important vs. very important) also influenced the association of that reason with smoking cessation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31067/1/0000744.pd

    Modulation of a human immunosuppressive lymphokine by monosaccharides

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    Soluble suppressor factor (SSF) is a recently purified human lymphokine produced by peripheral blood lymphocytes (PBL) in serum-free medium as a likely consequence of an autologous mixed lymphocyte reaction. Immunoregulatory actions of SSF include suppression of: polyclonal B cell activation, proliferative responses of normal PBL, and natural killer (NK) and antibody-dependent cellular cytotoxicity. We examined the ability of the monosaccharides fucose (Fuc), galactose (Gal), glucose (Glc), and mannose (Man) to reverse SSF-mediated suppression of NK activity. Fuc and Gal can partially or completely reverse SSF-mediated suppression at four effector:target cell ratios. Man and Glc were unable to significantly reverse SSF-mediated suppression. Fuc or Gal was added to PBL at various times after addition of SSF. SSF-mediated suppression of NK cytotoxicity becomes irreversible with respect to these monosaccharides during the first 24 hr of PBL exposure to SSF. To explore the mechanism behind this block of SSF-mediated suppression, Fuc or Gal (50 mM) was cultured with PBL for 24 hr before addition of SSF, or with SSF for 24 hr before addition to PBL. Our experiments indicate that SSF is directly interacting with these monosaccharides, and may function by recognizing specific sugar moieties on the surface of effector cells.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29181/1/0000234.pd

    Anemia, costs and mortality in Chronic Obstructive Pulmonary Disease

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    BACKGROUND: Little is known about cost implications of anemia and its association with mortality in chronic obstructive pulmonary disease (COPD). This claims analysis addresses these questions. METHODS: Using the the US Medicare claims database (1997–2001), this study identified Medicare enrollees with an ICD-9 diagnosis of COPD. Concomitant anemia was identified based on ICD-9 codes or receipt of transfusions. Persons with anemia secondary to another disease state, a nutritional deficiency or a hereditary disease were excluded. Medicare claims and payments, resource utilization and mortality were compared between COPD patients with and without anemia. RESULTS: Of the 132,424 enrollees with a COPD diagnosis, 21% (n = 27,932) had concomitant anemia. At baseline, anemic patients were older, had more co-morbidities and higher rates of health care resource use than non-anemic individuals with COPD. In a univariate analysis annual Medicare payments for persons with anemia were more than double for those without anemia (1,466vs.1,466 vs. 649, p < 0.001), the direction maintained in all categories of payments. Adjusting for demographics, co-morbidities, and other markers of disease severity revealed that anemia was independently associated with 3,582incrementalincreaseperpatient(953,582 incremental increase per patient (95% CI: 3,299 to $3,865) in Medicare annual reimbursements. The mortality rate among COPD patients with anemia was 262 vs. 133 deaths per 1,000 person-years among those without anemia (p < 0.001). CONCLUSION: Anemia was present in 21% of COPD patients. Although more prevalent in more severely ill COPD patients, anemia significantly and independently contributes to the costs of care for COPD and is associated with increased mortality

    Measurement of an AGN Central Mass on Centiparsec Scales: Results of Long-Term Optical Monitoring of Arp 102B

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    The optical spectrum of the broad-line radio galaxy Arp 102B has been monitored for more than thirteen years to investigate the nature of the source of its broad, double-peaked hydrogen Balmer emission lines. The shape of the lines varied subtly; there was an interval during which the variation in the ratio of the fluxes of the two peaks appeared to be sinusoidal, with a period of 2.16 years and an amplitude of about 16% of the average value. The variable part of the broad H-alpha line is well fit by a model in which a region of excess emission (a quiescent ``hot spot'') within an accretion disk (fitted to the non-varying portion of the double-peaked line) completes at least two circular orbits and eventually fades. Fits to spectra from epochs when the hot spot is not present allow determination of the disk inclination, while fits for epochs when it is present provide a measurement of the radius of the hot spot's orbit. From these data and the period of variation, we find that the mass within the hot spot's orbit is 2.2 +0.2/-0.7 times 10^8 solar masses, within the range of previous estimates of masses of active galactic nuclei. Because this mass is determined at a relatively small distance (~1000 AU) from the central body, it is extremely difficult to explain without assuming that a supermassive black hole lies within Arp 102B. The lack of any systematic change in the velocity of the blue peak over time yields a lower limit on the combined mass of the two bodies in a binary black hole model like that of Gaskell (1983) of 10^10 solar masses.Comment: 29 pages, including 6 figures; to appear in the Astrophysical Journal 199

    Patient experiences of cancer care: scoping review, future directions, and introduction of a new data resource: Surveillance Epidemiology and End Results-Consumer Assessment of Healthcare Providers and Systems (SEER-CAHPS)

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    The shift towards providing high value cancer care has placed increasing importance on patient experiences. This scoping review summarizes patient experience literature, highlights research gaps, and provides future research directions. We then introduce a new resource that links the National Cancer Institute’s Surveillance Epidemiology and End Results (SEER) program with the Centers for Medicare and Medicaid Services Consumer Assessment of Healthcare Providers and Systems (CAHPS) survey and longitudinal medical claims data. We conducted a scoping review to identify relevant research within the Medicare CAHPS domain that examine factors associated with patient-reported experiences with their cancer care. Gaps indicate a need for population-based research to explore relationships between cancer patient experiences, healthcare utilization, and subsequent patient outcomes. SEER-CAHPS, a publicly accessible data resource, may assist in addressing these gaps by linking cancer registry (SEER), survey data reported by Medicare beneficiaries (CAHPS), and Medicare claims, providing unique insight into quality of care. Linked data include 231,089 surveys from patients with a cancer diagnosis, and 4,236,529 surveys from patients without a cancer diagnosis. Results indicate substantial gaps in our knowledge of patient experiences and the need for additional resources. SEER-CAHPS links direct patient feedback with cancer registry and Medicare claims, making it an important source of information on experiences and healthcare utilization. Increasing recognition of the importance of patient-centeredness points to the need for population-based studies. Findings from SEER-CAHPS will inform initiatives to improve care delivery
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