Apparatus for measuring charged particle beam

An apparatus to measure the incident charged particle beam flux while effectively eliminating losses to reflection and/or secondary emission of the charged particle beam being measured is described. It comprises a sense cup through which the charged particle beam enters. A sense cone forms the rear wall of the interior chamber with the cone apex adjacent the entry opening. An outer case surrounds the sense cup and is electrically insulated therefrom. Charged particles entering the interior chamber are trapped and are absorbed by the sense cup and cone and travel through a current measuring device to ground

Spin-correlations and magnetic structure in an Fe monolayer on 5d transition metal surfaces

We present a detailed first principles study on the magnetic structure of an Fe monolayer on different surfaces of 5d transition metals. We use the spin-cluster expansion technique to obtain parameters of a spin model, and predict the possible magnetic ground state of the studied systems by employing the mean field approach and in certain cases by spin dynamics calculations. We point out that the number of shells considered for the isotropic exchange interactions plays a crucial role in the determination of the magnetic ground state. In the case of Ta substrate we demonstrate that the out-of-plane relaxation of the Fe monolayer causes a transition from ferromagnetic to antiferromagnetic ground state. We examine the relative magnitude of nearest neighbour Dzyaloshinskii-Moriya (D) and isotropic (J) exchange interactions in order to get insight into the nature of magnetic pattern formations. For the Fe/Os(0001) system we calculate a very large D/J ratio, correspondingly, a spin spiral ground state. We find that, mainly through the leading isotropic exchange and Dzyaloshinskii-Moriya interactions, the inward layer relaxation substantially influences the magnetic ordering of the Fe monolayer. For the Fe/Re(0001) system characterized by large antiferromagnetic interactions we also determine the chirality of the $120^{\circ}$ N\'eel-type ground state.Comment: 15 pages, 8 figures, 2 table

Lower respiratory tract infections and community acquired pneumonia in adults

Copyright © 2004 Royal Australian College of General Practitioners Copyright to Australian Family Physician. Reproduced with permission. Permission to reproduce must be sought from the publisher, The Royal Australian College of General Practitioners.BACKGROUND: Lower respiratory tract infections--acute bronchitis and community acquired pneumonia (CAP)--are important causes of morbidity in Australia. Acute bronchitis is often treated with antibiotics, although the cause is usually viral. Community acquired pneumonia may be fatal, particularly in the elderly, therefore appropriate assessment and management is essential. OBJECTIVE: This article describes the aetiology, clinical assessment, investigations and management of acute bronchitis and CAP in the community. DISCUSSION: Clinical assessment is important for acute bronchitis and CAP, with investigations such as C reactive protein, serology, and chest X-ray informing diagnosis and management of the latter. Causative organisms are usually not identified, but are presumed to be viral for acute bronchitis, and Streptococcus pneumoniae for CAP; although 'atypicals' are also important. Antibiotics should generally not be prescribed for acute bronchitis, however, there is some evidence they may provide limited benefits in patients who have chest signs, are very unwell, are older, have comorbidities, or smoke. In patients with CAP, treated outside of hospital, the combination of amoxycillin and doxycycline/roxithromycin is the treatment of choice.Nigel Stocks; John Turnidge; Alan Crocket

Phase locking below rate threshold in noisy model neurons

The property of a neuron to phase-lock to an oscillatory stimulus before adapting its spike rate to the stimulus frequency plays an important role for the auditory system. We investigate under which conditions neurons exhibit this phase locking below rate threshold. To this end, we simulate neurons employing the widely used leaky integrate-and-fire (LIF) model. Tuning parameters, we can arrange either an irregular spontaneous or a tonic spiking mode. When the neuron is stimulated in both modes, a significant rise of vector strength prior to a noticeable change of the spike rate can be observed. Combining analytic reasoning with numerical simulations, we trace this observation back to a modulation of interspike intervals, which itself requires spikes to be only loosely coupled. We test the limits of this conception by simulating an LIF model with threshold fatigue, which generates pronounced anticorrelations between subsequent interspike intervals. In addition we evaluate the LIF response for harmonic stimuli of various frequencies and discuss the extension to more complex stimuli. It seems that phase locking below rate threshold occurs generically for all zero mean stimuli. Finally, we discuss our findings in the context of stimulus detection

Recursive renormalization of the singlet one-pion-exchange plus point-like interactions

The subtracted kernel approach is shown to be a powerful method to be implemented recursively in scattering equations with regular plus point-like interactions. The advantages of the method allows one to recursively renormalize the potentials, with higher derivatives of the Dirac-delta, improving previous results. The applicability of the method is verified in the calculation of the $^1S_0$ nucleon-nucleon phase-shifts, when considering a potential with one-pion-exchange plus a contact interaction and its derivatives. The $^1S_0$ renormalization parameters are fitted to the data. The method can in principle be extended to any derivative order of the contact interaction, to higher partial waves and to coupled channels.Comment: 12 pages, 3 figure

Cluster coherent potential approximation for electronic structure of disordered alloys

We extend the single-site coherent potential approximation (CPA) to include the effects of non-local disorder correlations (alloy short-range order) on the electronic structure of random alloy systems. This is achieved by mapping the original Anderson disorder problem to that of a selfconsistently embedded cluster. This cluster problem is then solved using the equations of motion technique. The CPA is recovered for cluster size $N_{c}=1$, and the disorder averaged density-of-states (DOS) is always positive definite. Various new features, compared to those observed in CPA, and related to repeated scattering on pairs of sites, reflecting the effect of SRO are clearly visible in the DOS. It is explicitly shown that the cluster-CPA method always yields positive-definite DOS. Anderson localization effects have been investigated within this approach. In general, we find that Anderson localization sets in before band splitting occurs, and that increasing partial order drives a continuous transition from an Anderson insulator to an incoherent metal.Comment: 7 pages, 6 figures. submitted to PR

Psychological perspectives in urinary incontinence: a metasynthesis

Introduction: Urinary incontinence with co-morbid depression has been found to have a significant effect on quality of life. Examining the associations between the psychosocial factors related to urinary incontinence and mental health may help in improving the care for patients with these conditions. The aim of this research study is to explore the relationship between mental health status and urinary incontinence, focusing on the role of psychosocial factors. Materials and Methods: A search of Medline, CINAHL and SCOPUS databases yielded 15 studies on the topic, and 10 studies were found to be in scope. A metasynthesis using Noblit and Hare’s approach of meta-ethnography was undertaken. This involved a number of steps including determining how studies are related and identifying major themes. Results: Three psychosocial aspects of urinary incontinence appear to influence mental health status: living with, management of and attitudes about incontinence. Other smaller component themes included control, seeking help and personal beliefs. Discussion: Psychosocial factors appear to mediate the relationship between urinary incontinence and mental health status. An increased awareness of the major psychosocial issues that can influence both incontinence and mental health may contribute to a better management of the condition as well as reduce the burden of the condition on individuals. Conclusion: Incontinence and psychological wellbeing are intertwined and this adversely affects a number of aspects of life. Enquiring about the mental health status of those with incontinence should include an assessment of psychosocial factors to help reduce the burden of incontinence. To improve the management of these conditions, further research should investigate whether psychological issues precede incontinence or vice versa.JC Avery, AJ Braunack-Mayer, NP Stocks, AW Taylor, P Dugga