A Proton Synchrotron Blazar Model for Flaring in Markarian~501

(abr.) The spectral energy distribution (SED) of blazars typically has a double-humped appearance usually interpreted in terms of synchrotron self-Compton models. In proton blazar models, the SED is instead explained in terms of acceleration of protons and subsequent cascading. We discuss a variation of the Synchrotron Proton Blazar model, first proposed by M\"ucke & Protheroe (1999), in which the low energy part of the SED is mainly synchrotron radiation by electrons co-accelerated with protons which produce the high energy part of the SED mainly asproton synchrotron radiation. Using a Monte Carlo/numerical technique to simulate the interactions and subsequent cascading of the accelerated protons, we are able to fit the observed SED of Markarian 501 during the April 1997 flare. We find that the emerging cascade spectra initiated by gamma-rays from $\pi^0$ decay and by $e^\pm$ from $\mu^\pm$ decay turn out to be relatively featureless. Synchrotron radiation produced by $\mu^\pm$ from $\pi^\pm$ decay, and even more importantly by protons, and subsequent synchrotron-pair cascading, is able to reproduce well the high energy part of the SED. For this fit we find that synchrotron radiation by protons dominates the TeV emission, pion photoproduction being less important with the consequence that we predict a lower neutrino flux than in other proton blazar models.Comment: 28 pages, 8 Figures, accepted for publication in Astropart.Phy

Neutrino Emission from HBLs and LBLs

The Synchrotron Proton Blazar model is a promising model to explain high energy emission from gamma-ray loud BL Lac objects like Mkn 421. In contrast to leptonic models, the hadronic explanation of gamma-ray emission predicts ultrahigh energy neutrinos. The predicted neutrino spectra from a typical High-energy cutoff BL Lac Object (HBL) and a Low-energy cutoff BL Lac Object (LBL) are presented. We find that cooling due to muon synchrotron radiation causes a cutoff of the neutrino spectrum at $\sim 10^{18}$ eV, with the exception of $\nu_\mu$ from kaon decay which may extend to higher energies if meson production takes place in the secondary resonance region of the cross section. The impact of the neutrino output from both source populations to the diffuse neutrino background is discussed.Comment: 4 pages, 3 figures, to appear in: Proc. 27th Int. Cosmic Ray Conf., Hamburg/German

Monte-Carlo simulations of photohadronic processes in astrophysics

A new Monte Carlo program for photohadronic interactions of relativistic nucleons with an ambient photon radiation field is presented. The event generator is designed to fulfil typical astrophysical requirements, but can also be used for radiation and background studies at high energy colliders such as LEP2 and HERA, as well as for simulations of photon induced air showers. We consider the full photopion production cross section from the pion production threshold up to high energies. It includes resonance excitation and decay, direct single pion production and diffractive and non-diffractive multiparticle production. The cross section of each individual process is calculated by fitting experimental data, while the kinematics is determined by the underlying particle production process. We demonstrate that our model is capable of reproducing known accelerator data over a wide energy range.Comment: 39 pages, 17 figures, submitted to Comp.Phys.Co

Application of the synchrotron proton blazar model to BL Lac objects

We apply the synchrotron proton blazar (SPB) model to the April 1997 flare of Markarian 501 and find we are able to fit the observed spectral energy distribution. We explore the effect of target photon density on the high energy part of the spectral energy distribution (SED) for fixed assumed magnetic field, emission region size and Doppler factor and find that the luminosity and peak frequency of the high energy part of the SED may depend on the luminosity of the low energy part of the SED in high-frequency peaked BL Lac objects (HBL).Comment: 4 pages, 3 figures, to appear in proceedings of ``Heidelberg International Symposium on High Energy Gamma-Ray Astronomy'' edited by Felix Aharonian and Heinz Voelk, AIP Conf. Pro

Culture shock and healthcare workers in remote Indigenous communities of Australia: what do we know and how can we measure it?

Introduction: Culture shock or cultural adaptation is a significant issue confronting non-Indigenous health professionals working in remote Indigenous communities in Australia. This article is presented in two parts. The first part provides a thorough background in the theory of culture shock and cultural adaptation, and a comprehensive analysis of the consequences, causes, and current issues around the phenomenon in the remote Australian healthcare context. Second, the article presents the results of a comprehensive literature review undertaken to determine if existing studies provide tools which may measure the cultural adaptation of remote health professionals. Methods: A comprehensive literature review was conducted utilising the meta-databases CINAHL and Ovid Medline. Results: While there is a plethora of descriptive literature about culture shock and cultural adaptation, empirical evidence is lacking. In particular, no empirical evidence was found relating to the cultural adaptation of non-Indigenous health professionals working in Indigenous communities in Australia. In all, 15 international articles were found that provided empirical evidence to support the concept of culture shock. Of these, only 2 articles contained tools that met the pre-determined selection criteria to measure the stages of culture shock. The 2 instruments identified were the Culture Shock Profile (CSP) by Zapf and the Culture Shock Adaptation Inventory (CSAI) by Juffer. Conclusions: There is sufficient evidence to determine that culture shock is a significant issue for non-Indigenous health professionals working in Indigenous communities in Australia. However, further research in this area is needed. The available empirical evidence indicates that a measurement tool is possible but needs further development to be suitable for use in remote Indigenous communities in Australia

Bibliography: Nursing Research and Practice with Refugees.

Nurses work directly with refugees both in refugee camps and in their places of resettlement, often providing first contact with the U.S. health care system. This 1990 bibliography of articles in English by nurses who have worked with refugees seeks to provide better access to a widely dispersed literature, much of it in masters theses or conference proceedings. Refugee groups from around the world are covered and only articles that are not in the mainstream of scientific citation, and therefore difficult to find, are included.Southeast Asia Refugee Studies Project. Occasional Papers, Number Ten

Attosecond Precision Multi-km Laser-Microwave Network

Synchronous laser-microwave networks delivering attosecond timing precision are highly desirable in many advanced applications, such as geodesy, very-long-baseline interferometry, high-precision navigation and multi-telescope arrays. In particular, rapidly expanding photon science facilities like X-ray free-electron lasers and intense laser beamlines require system-wide attosecond-level synchronization of dozens of optical and microwave signals up to kilometer distances. Once equipped with such precision, these facilities will initiate radically new science by shedding light on molecular and atomic processes happening on the attosecond timescale, such as intramolecular charge transfer, Auger processes and their impact on X-ray imaging. Here, we present for the first time a complete synchronous laser-microwave network with attosecond precision, which is achieved through new metrological devices and careful balancing of fiber nonlinearities and fundamental noise contributions. We demonstrate timing stabilization of a 4.7-km fiber network and remote optical-optical synchronization across a 3.5-km fiber link with an overall timing jitter of 580 and 680 attoseconds RMS, respectively, for over 40 hours. Ultimately we realize a complete laser-microwave network with 950-attosecond timing jitter for 18 hours. This work can enable next-generation attosecond photon-science facilities to revolutionize many research fields from structural biology to material science and chemistry to fundamental physics.Comment: 42 pages, 13 figure

Treatment of ocular surface squamous neoplasia with Mitomycin C

Aim: To report the outcome of treatment of non-invasive ocular surface squamous neoplasia (or conjunctivalcorneal intra-epithelial neoplasia (CCIN)) where topical mitomycin C (MMC) has been used in the treatment regimen. Design: Prospective, non-comparative interventional case series. Participants: 91 primary or recurrent CCIN lesions from 90 patients treated in a single ocular oncology centre over a 10.5-year period. Intervention 73 cases of localised, non-invasive CCIN and eight cases of recurrent CCIN received a treatment regimen of surgical excision6cryotherapy, followed by two to three 1-week cycles of adjuvant topical MMC (0.04% four times a day). 10 cases of diffuse CCIN received two to three 1-week cycles of topical MMC (0.04% four times a day) as sole primary treatment. Main outcome measure: Successful treatment was defined as no clinical recurrence of CCIN. Results: Mean follow-up of 56.8 months (range 5.8 to 119.8) and median 57.3 months, revealed no recurrences (0%) in the localised primary group, and one persistent case and two recurrences (30%) in the diffuse primary group. There was one recurrence (12.5%) in the recurrent group, but this was in the only eye with a diffuse type of recurrence. Conclusions: MMC treatment following surgical excision appears to decrease the recurrence rate of localised CCIN and should be considered as adjuvant therapy in primary treatment. MMC should also be considered as adjuvant therapy in the treatment of localised recurrent disease. MMC may be used as sole therapy in more diffuse disease, but close ongoing follow-up is recommended in view of the significant risk of persistent or recurrent disease.A. Gupta and J. Mueck