958 research outputs found

    Self-consistent predictions for LIER-like emission lines from post-AGB stars

    Full text link
    Early type galaxies (ETGs) frequently show emission from warm ionized gas. These Low Ionization Emission Regions (LIERs) were originally attributed to a central, low-luminosity active galactic nuclei. However, the recent discovery of spatially-extended LIER emission suggests ionization by both a central source and an extended component that follows a stellar-like radial distribution. For passively-evolving galaxies with old stellar populations, hot post-Asymptotic Giant Branch (AGB) stars are the only viable extended source of ionizing photons. In this work, we present the first prediction of LIER-like emission from post-AGB stars that is based on fully self-consistent stellar evolution and photoionization models. We show that models where post-AGB stars are the dominant source of ionizing photons reproduce the nebular emission signatures observed in ETGs, including LIER-like emission line ratios in standard optical diagnostic diagrams and Hα\alpha equivalent widths of order 0.1-3 angstroms. We test the sensitivity of LIER-like emission to the details of post-AGB models, including the mass loss efficiency and convective mixing efficiency, and show that line strengths are relatively insensitive to post-AGB timescale variations. Finally, we examine the UV-optical colors of the models and the stellar populations responsible for the UV-excess observed in some ETGs. We find that allowing as little as 3% of the HB population to be uniformly distributed to very hot temperatures (30,000 K) produces realistic UV colors for old, quiescent ETGs.Comment: ApJ accepted. 20 pages, 8 figure

    ADOPTION OF VETERINARY SURGEON SERVICES BY SHEEP AND GOAT FARMERS IN QWAQWA

    Get PDF
    A number of technology transfer (diffusion) programmes involving amongst others veterinary surgeon services subsidised by the government, were launched in the former homelands of South Africa between 1980 and 1993. Many of these programmes were discontinued after the general election of 1994. In order to evaluate the adoption of technology in Qwaqwa, a former Sotho speaking homeland, two Logit models were fit using the conventional definition of an adopter and an adapted definition, which included potential adopters with the adopters. Where the conventional definition of adoption was estimated, livestock income per LSU, ram technology, roads and suppliers of livestock inputs are significant variables contributing to adoption. The results of the adapted model reveal that farming efficiency (weaning percentage), type of farmer (sheep as percentage of the total small ruminant herd) and ram technology, prove to be significant variables predicting adoption. It was also found that the characteristics of potential adopters gravitate more to adopters than to non-adopters. These results indicated that the adapted definition presented a more accurate prediction than the conventional definition. The results of this study indicate the policy necessary to further accelerate the diffusion of veterinary surgeon services by means of the development of a better infrastructure, the reintroduction of subsidised veterinary surgeon services at the sheering sheds as well as a better flow of information to farmers in Qwaqwa.Livestock Production/Industries,

    Epide·miology of non-fatal injuries due to external causes in Johannesburg-Soweto Part I. Methodology and materials

    Get PDF
    In this, the first of two articles examining the epidemiology of non-fatal trauma in Johannesburg-Soweto, we define case inclusion criteria, and discuss the methodology and materials used in this low-cost, hospital-based survey. The survey was conducted between 8 June 1989 and 24 August 1990. Sampling of both inpatient trauma cases and those seen in casualty departments took place in 6 state and 5 private hospitals located within or nearby the Johannesburg magisterial district. Demographic details about each patient, as well as information concerning spatial and temporal details of the incident, involvement of alcohol or drugs, diagnosis, severity of injury, and placement after casualty treatment, were collected by interviewing each patient. Data concerning the age, sex and racial composition of the background population were assembled from a number of sources. After discussing the internal limitations of this methodology, it is concluded that its findings may be of limited use for improving secondary interventions, but are of definite value for trauma prevention programmes

    Epidemiology of non-fatal injuries due to external causes in Johannesburg-Soweto Part 11. Incidence and determinants

    Get PDF
    A total of 3535 trauma cases were enumerated in Johannesburg- Soweto between 1989 and 1990 in the course of 271 hospital ward rounds and 43 casualty watches. The overall trauma incidence was 2886 new cases per annum per 100000 population, rising to 19872 for coloured males aged 20 - 24 years and to 8761 for black males aged 20 - 24 years. Overall the malelfemale ratio was 2,9 rising to 6 or more in adolescence (15 - 19) for blacks andcoloureds. There were some 156 new resident cases of trauma daily; half these were victims of interpersonal violence, and coloureds constituted 22% of this group, although forming only 8% of the denominator population. Witluegards to cause, most trauma among blacks and coloureds arose from interpersonal violence and significantly less from transport accidents. Among blacks injured in transport accidents (the majority of which involved motor vehicles) most were pedestrians, whereas most whites injured in such accidents were occupants of vehicles. For all groups trauma was most likely to be incurred 'in the street' although for white and coloured women the home was most dangerous. The implications of these and related findings for treatment and prevention and briefly reviewed

    Die Bedeutung einer Ausfallbedrohtheit von Versicherungskontrakten - ein Beitrag zur Behavioral Insurance

    Full text link
    Kahneman/Tversky 1979 haben das theoretische Konstrukt der Probabilistic Insurance Kontrakte in die Literatur eingeführt. Hiermit werden Versicherungsverträge bezeichnet, deren Erfüllung im Leistungsfalle aufgrund einer möglichen Insolvenz des Versicherungsunternehmens nicht gewährleistet ist. In Ausweitung einer Studie von Wakker/Thaler/Tversky 1997 wird in der vorliegenden Arbeit eine experimentelle Untersuchung durchgeführt, wobei die Zahlungsbereitschaft potentieller Versicherungsnehmer in Abhängigkeit des Ratings des den Versicherungskontrakt anbietenden Unternehmens festgestellt wird. Dabei zeigt sich, daß diese ausfallbedrohte Versicherungsprodukte relativ zu ausfallfreien Verträgen mit erheblichen Prämienabschlägen sanktionieren. Der Preisabschlag nimmt dabei mit sinkender Unternehmensbonität (erhöhter Ausfallgefahr) zu. Die Befragungsergebnisse zeigen zudem das neuartige Phänomen, daß mit zunehmender Ausfallbedrohtheit immer weniger Personen bereit sind, ausfallbedrohte Versicherungsprodukte überhaupt zu akzeptieren. Schließlich werden Schlußfolgerungen für die Steuerung von Versicherungsunternehmen diskutiert

    Open-label parallel dose tolerability study of three subcutaneous immunotherapy regimens in house dust mite allergic patients

    Get PDF
    Background The current maintenance dose (10,000 AUeq/monthly) of a subcutaneous allergoid for house dust mite (HDM) immunotherapy has previously shown significant clinical efficacy in patients with HDM induced allergic rhinitis or rhinoconjunctivitis. In order to comply with the 2009 EMA guidelines on immunotherapy products, a study was conducted to evaluate the safety, tolerability and short-term treatment effects of up-dosing regimens with high doses (up to 40,000 AUeq) of allergoid HDM immunotherapy. Methods In total 48 patients with HDM-allergic rhinitis or rhinoconjunctivitis (29 M/19 F; 18–53 years) were included and enrolled into one of three up-dosing regimens (1:4:4): 1) a regular regimen with up-dosing to 40,000 AUeq followed by two maintenance doses (total duration 17 weeks), 2) an intermediate regimen (14 weeks) or 3) a fast regimen (11 weeks). Safety and tolerability were evaluated by monitoring of early and late local reactions and systemic reactions. In addition, short-term effects were assessed by conjunctival provocation test (CPT) and levels of serum allergen-specific IgE, IgG and IgG4. Results Thirty-nine patients completed the study according to protocol. No early local reactions occurred. Late local reactions (LLR) were observed in 12% of the injections. In total, 31 systemic reactions, all grade 1, were reported of which two needed oral antihistamine treatment. No grade 2 or higher systemic reactions were observed. Six patients (15%) did not reach the highest dose due to LLR and/or systemic reactions needing antihistamines (20% in the regular regimen, 16% in the intermediate regimen and 13% in the fast regimen). At the end of the study, an improvement in the CPT was observed in 82.1% of patients, indirectly indicating an early treatment effect at the current dose and higher doses. In addition, IgG4 immunoglobulin levels were significantly increased in all groups following treatment. Conclusions In this open-label study, allergoid HDM immunotherapy in doses up to 40,000 AUeq was generally well tolerated and no clinically relevant safety issues were identified. In the safety aspects of the three up-dosing regimens no clinically relevant differences were encountered. Therefore, these dose ranges and up-dosing regimens can be safely included in future dose-finding efficacy studies

    Prognosis after surgery for multiple endocrine neoplasia type 1-related pancreatic neuroendocrine tumors:Functionality matters

    Get PDF
    Background: Metastasized pancreatic neuroendocrine tumors are the leading cause of death in patients with multiple endocrine neoplasia type 1. Aside from tumor size, prognostic factors of pancreatic neuroendocrine tumors are largely unknown. The present study aimed to assess whether the prognosis of patients with resected multiple endocrine neoplasia type 1-related nonfunctioning pancreatic neuroendocrine tumors differs from those with resected multiple endocrine neoplasia type 1-related insulinomas and assessed factors associated with prognosis.Methods: Patients who underwent resection of a multiple endocrine neoplasia type 1-related pancreatic neuroendocrine tumors between 1990 and 2016 were identified in 2 databases: the DutchMEN Study Group and the International MEN1 Insulinoma Study Group databases. Cox regression was performed to compare liver metastases-free survival of patients with a nonfunctioning pancreatic neuroendocrine tumors versus those with an insulinoma and to identify factors associated with liver metastases-free survival.Results: Out of 153 patients with multiple endocrine neoplasia type 1, 61 underwent resection for a nonfunctioning pancreatic neuroendocrine tumor and 92 for an insulinoma. Of the patients with resected lymph nodes, 56% (18/32) of nonfunctioning pancreatic neuroendocrine tumors had lymph node metastases compared to 10% (4/41) of insulinomas (P =.001). Estimated 10-year liver metastases-free survival was 63% (95% confidence interval 42%–76%) for nonfunctioning pancreatic neuroendocrine tumors and 87% (72%–91%) for insulinomas. After adjustment for size, World Health Organization tumor grade, and age, nonfunctioning pancreatic neuroendocrine tumors had an increased risk for liver metastases or death (hazard ratio 3.04 [1.47–6.30]). In pancreatic neuroendocrine tumors ≥2 cm, nonfunctioning pancreatic neuroendocrine tumors (2.99 [1.22–7.33]) and World Health Organization grade 2 (2.95 [1.02–8.50]) were associated with liver metastases-free survival.Conclusion: Patients with resected multiple endocrine neoplasia type 1-related nonfunctioning pancreatic neuroendocrine tumors had a significantly lower liver metastases-free survival than patients with insulinomas. Postoperative counseling and follow-up regimens should be tumor type specific and at least consider size and World Health Organization grade.</p
    • …
    corecore