1,828 research outputs found

    The consequences of executive turnover

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    The high rate of executive turnover in the healthcare industry is a major issue for health service organisations and their staff both in Australia and internationally. In the course of planning a research project examining nurse turnover at the clinical level within three Australian States/Territories, the researchers became aware of frequent executive turnover at all levels (State Department of Health, Area Health Service, hospital). Over a period of approximately 2 years there were 41 executives occupying 18 different positions, highlighting the scope of this issue in Australia. Few studies have examined the causes and consequences of this phenomenon in depth. Factors such as age, gender, education, lack of career advancement opportunities and remuneration have all been identified in the literature as important contributors to executive turnover. High turnover rates have been found to be associated with a number of negative consequences, including organisational instability, high financial costs, loss of human capital and adverse effects on staff morale and patient care. While the use of 'acting' roles may assist in filling executive positions on a temporary basis, consequences for the rest of the organisation are associated with their extended use. Steps which health services planners may take to attempt to minimise executive turnover include providing staff members with appropriate challenges and opportunities for growth and ensuring that a clear succession plan is in place to minimise the impact for the organisation and its staff. © The Author(s) 2011

    The 1989 and 2015 outbursts of V404 Cygni: a global study of wind-related optical features

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    The black hole transient V404 Cygni exhibited a bright outburst in June 2015 that was intensively followed over a wide range of wavelengths. Our team obtained high time resolution optical spectroscopy (~90 s), which included a detailed coverage of the most active phase of the event. We present a database consisting of 651 optical spectra obtained during this event, that we combine with 58 spectra gathered during the fainter December 2015 sequel outburst, as well as with 57 spectra from the 1989 event. We previously reported the discovery of wind-related features (P-Cygni and broad-wing line profiles) during both 2015 outbursts. Here, we build diagnostic diagrams that enable us to study the evolution of typical emission line parameters, such as line fluxes and equivalent widths, and develop a technique to systematically detect outflow signatures. We find that these are present throughout the outburst, even at very low optical fluxes, and that both types of outflow features are observed simultaneously in some spectra, confirming the idea of a common origin. We also show that the nebular phases depict loop patterns in many diagnostic diagrams, while P-Cygni profiles are highly variable on time-scales of minutes. The comparison between the three outbursts reveals that the spectra obtained during June and December 2015 share many similarities, while those from 1989 exhibit narrower emission lines and lower wind terminal velocities. The diagnostic diagrams presented in this work have been produced using standard measurement techniques and thus may be applied to other active low-mass X-ray binaries.Comment: Accepted for publication in MNRAS. 23 pages paper, plus a 9 pages appendix with extra tables and figures. 18 figures are included in the paper and 8 in the appendi

    INTEGRAL long-term monitoring of the Supergiant Fast X-ray Transient XTE J1739-302

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    In the past few years, a new class of High Mass X-Ray Binaries (HMXRB) has been claimed to exist, the Supergiant Fast X-ray Transients (SFXT). These are X-ray binary systems with a compact companion orbiting a supergiant star which show very short and bright outbursts in a series of activity periods overimposed on longer quiescent periods. Only very recently the first attempts to model the behaviour of these sources have been published, some of them within the framework of accretion from clumpy stellar winds.Our goal is to analyze the properties of XTE J1739-302/IGR J17391-3021 within the context of the clumpy structure of the supergiant wind. We have used INTEGRAL and RXTE/PCA observations in order to obtain broad band (1-200 keV) spectra and light curves of XTE J1739-302 and investigate its X-ray spectrum and temporal variability. We have found that XTE J1739-302 follows a much more complex behaviour than expected. Far from presenting a regular variability pattern, XTE J1739-302 shows periods of high, intermediate, and low flaring activity.Comment: 9 pages, 7 figures, accepted for publication in A&

    Airports at Risk: The Impact of Information Sources on Security Decisions

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    Security decisions in high risk organizations such as airports involve obtaining ongoing and frequent information about potential threats. Utilizing questionnaire survey data from a sample of airport employees in European Airports across the continent, we analyzed how both formal and informal sources of security information affect employee's decisions to comply with the security rules and directives. This led us to trace information network flows to assess its impact on the degree employees making security decisions comply or deviate with the prescribed security rules. The results of the multivariate analysis showed that security information obtained through formal and informal networks differentially determine if employee will comply or not with the rules. Information sources emanating from the informal network tends to encourage employees to be more flexible in their security decisions while formal sources lead to be more rigid with complying with rules and protocols. These results suggest that alongside the formal administrative structure of airports, there exists a diverse and pervasiveness set of informal communications networks that are a potent factor in determining airport security levels

    Two years of monitoring Supergiant Fast X-ray Transients with Swift

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    We present two years of intense Swift monitoring of three SFXTs, IGR J16479-4514, XTE J1739-302, and IGR J17544-2619 (since October 2007). Out-of-outburst intensity-based X-ray (0.3-10keV) spectroscopy yields absorbed power laws with by hard photon indices (G~1-2). Their outburst broad-band (0.3-150 keV) spectra can be fit well with models typically used to describe the X-ray emission from accreting NSs in HMXBs. We assess how long each source spends in each state using a systematic monitoring with a sensitive instrument. These sources spend 3-5% of the total in bright outbursts. The most probable flux is 1-2E-11 erg cm^{-2} s^{-1} (2-10 keV, unabsorbed), corresponding to luminosities in the order of a few 10^{33} to 10^{34} erg s^{-1} (two orders of magnitude lower than the bright outbursts). The duty-cycle of inactivity is 19, 39, 55%, for IGR J16479-4514, XTE J1739-302, and IGR J17544-2619, respectively. We present a complete list of BAT on-board detections further confirming the continued activity of these sources. This demonstrates that true quiescence is a rare state, and that these transients accrete matter throughout their life at different rates. X-ray variability is observed at all timescales and intensities we can probe. Superimposed on the day-to-day variability is intra-day flaring which involves variations up to one order of magnitude that can occur down to timescales as short as ~1ks, and whichcan be explained by the accretion of single clumps composing the donor wind with masses M_cl~0.3-2x10^{19} g. (Abridged)Comment: Accepted for publication in MNRAS. 17 pages, 11 figures, 8 table

    Probing stellar winds and accretion physics in high-mass X-ray binaries and ultra-luminous X-ray sources with LOFT

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    This is a White Paper in support of the mission concept of the Large Observatory for X-ray Timing (LOFT), proposed as a medium-sized ESA mission. We discuss the potential of LOFT for the study of high-mass X-ray binaries and ultra-luminous X-ray sources. For a summary, we refer to the paper.Comment: White Paper in Support of the Mission Concept of the Large Observatory for X-ray Timing. (v2 few typos corrected

    Limb salvage with isolated perfusion for soft tissue sarcoma: could less TNF-α be better?

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    Background: The optimal dose of TNF-α delivered by isolated limb perfusion (ILP) in patients with locally advanced soft tissue sarcoma is still unknown. Patients and methods: Randomised phase II trial comparing hyperthermic ILP (38-40°) with melphalan and one of the four assigned doses of TNF-α: 0.5 mg, 1 mg, 2 mg, and 3/4 mg upper/lower limb. The main end point was objective tumour response on MRI. Secondary end points were histological response, rate of amputation and toxicity. Resection of the remnant tumour was performed 2-3 months after ILP. The sample size was calculated assuming a linear increase of 10% in the objective response rates between each dose level group. Results: One hundred patients (25 per arm) were included. Thirteen per cent of patients had a systemic leakage with a cardiac toxicity in six patients correlated with high doses of TNF-α. Objective tumour responses were: 68%, 56%, 72% and 64% in the 0.5 mg, 1 mg, 2 mg and 3 or 4 mg arms, respectively (NS). Sixteen per cent of patients were not operated, 71% had a conservative surgery and 13% were amputated with no difference between the groups. With a median follow-up of 24 months, the 2 year overall and disease-free survival rates (95% CI) were 82% (73% to 89%) and 49% (39% to 59%), respectively. Conclusion: At the range of TNF-α doses tested, there was no dose effect detected for the objective tumour response, but systemic toxicity was significantly correlated with higher TNF-α doses. Efficacy and safety of low-dose TNF-α could greatly facilitate ILP procedures in the near futur

    Phase III study of nilotinib versus best supportive care with or without a TKI in patients with gastrointestinal stromal tumors resistant to or intolerant of imatinib and sunitinib

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    Background This phase III open-label trial investigated the efficacy of nilotinib in patients with advanced gastrointestinal stromal tumors following prior imatinib and sunitinib failure. Patients and methods Patients were randomized 2:1 to nilotinib 400 mg b.i.d. or best supportive care (BSC; BSC without tyrosine kinase inhibitor, BSC+imatinib, or BSC+sunitinib). Primary efficacy end point was progression-free survival (PFS) based on blinded central radiology review (CRR). Patients progressing on BSC could cross over to nilotinib. Results Two hundred and forty-eight patients enrolled. Median PFS was similar between arms (nilotinib 109 days, BSC 111 days; P=0.56). Local investigator-based intent-to-treat (ITT) analysis showed a significantly longer median PFS with nilotinib (119 versus 70 days; P=0.0007). A trend in longer median overall survival (OS) was noted with nilotinib (332 versus 280 days; P=0.29). Post hoc subset analyses in patients with progression and only one prior regimen each of imatinib and sunitinib revealed a significant difference in median OS of >4 months in favor of nilotinib (405 versus 280 days; P=0.02). Nilotinib was well tolerated. Conclusion In the ITT analysis, no significant difference in PFS was observed between treatment arms based on CRR. In the post hoc subset analyses, nilotinib provided significantly longer median O

    The VLT-FLAMES Tarantula survey XX. The nature of the X-ray bright emission-line star VFTS 399

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    Context. The stellar population of the 30 Doradus star-forming region in the Large Magellanic Cloud contains a subset of apparently single, rapidly rotating O-type stars. The physical processes leading to the formation of this cohort are currently uncertain. Aims. One member of this group, the late O-type star VFTS 399, is found to be unexpectedly X-ray bright for its bolometric luminosity − in this study we aim to determine its physical nature and the cause of this behaviour. Methods. To accomplish this we performed a time-resolved analysis of optical, infrared and X-ray observations. Results. We found VFTS 399 to be an aperiodic photometric variable with an apparent near-IR excess. Its optical spectrum demonstrates complex emission profiles in the lower Balmer series and select He i lines − taken together these suggest an OeBe classification. The highly variable X-ray luminosity is too great to be produced by a single star, while the hard, non-thermal nature suggests the presence of an accreting relativistic companion. Finally, the detection of periodic modulation of the X-ray lightcurve is most naturally explained under the assumption that the accretor is a neutron star. Conclusions. VFTS 399 appears to be the first high-mass X-ray binary identified within 30 Dor, sharing many observational characteristics with classical Be X-ray binaries. Comparison of the current properties of VFTS 399 to binary-evolution models suggests a progenitor mass ≳25 M⊙ for the putative neutron star, which may host a magnetic field comparable in strength to those of magnetars. VFTS 399 is now the second member of the cohort of rapidly rotating “single” O-type stars in 30 Dor to show evidence of binary interaction resulting in spin-up, suggesting that this may be a viable evolutionary pathway for the formation of a subset of this stellar population
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