A study on whether the wood-saxon or the woods-saxon square parametrisation is appropriate for the phenomenological representation of different α \alpha -particle nucleus folding potentials

The Woods-Saxon (WS) and the squared Woods-Saxon (WS)$^{2}$ parametrisations for the single and double folding potentials were tested. We showed that the (WS)$^{2}$ form is appropriate for single as well as double folding approaches

On the formfactor of the imaginary part and its coupling to the real optical potential for the α\alpha-nucleus scattering

The model-independent formfactor of the absorptive cc-nucleus potential was calculated and compared with model dependent ones. The coupling between the shapes of the real and imaginary potential is discussed

Elastic scattering of 27.5 MeV alpha particles on 27^{27}Al, 28^{28}Si, 32^{32}S, Ti and 59^{59}Co nuclei and the r0r_{0} discrete ambiguity of the optical potential

Angular distributions for elastic scattering of alpha particles on $^{27}$Al, $^{28}$Si, $^{32}$S, Ti and $^{59}$Co nuclei have been measured in the angular range from about 20$^{\circ}$ to 179$^{\circ}$ (LAB). The experimental data were fitted with the optical model in full angular range. Many sets of four-parameter potentials, describing the elastic scattering, were found with the depths of the real part ranging from 40 to 450 MeV. A new discrete ambiguity in the optical model namely in $r_{0}$ was observed

Statistical analysis of excitation functions for elastic and inelastic scattering of α\alpha-particles on Mg and Si nuclei

The excitation functions for inelastic $\alpha$-scattering leading to the low lying excited states in $^{24}$Mg and $^{28}$Si were measured at $\Theta_{LAB}$ = 170°, 175° and 179° in the LAB energy range 22.75–28.40 MeV. Statistical analysis of these excitation functions and those previously measured for elastic scattering was performed. The direct interaction contribution $\mathit{y}_{D}$ to the reaction studied was obtained from probability distributions of cross sections and from correlation coefficients. Cross correlation coefficients between different reaction channels were calculated

Asymptotic stability, concentration, and oscillation in harmonic map heat-flow, Landau-Lifshitz, and Schroedinger maps on R^2

We consider the Landau-Lifshitz equations of ferromagnetism (including the harmonic map heat-flow and Schroedinger flow as special cases) for degree m equivariant maps from R^2 to S^2. If m \geq 3, we prove that near-minimal energy solutions converge to a harmonic map as t goes to infinity (asymptotic stability), extending previous work down to degree m = 3. Due to slow spatial decay of the harmonic map components, a new approach is needed for m=3, involving (among other tools) a "normal form" for the parameter dynamics, and the 2D radial double-endpoint Strichartz estimate for Schroedinger operators with sufficiently repulsive potentials (which may be of some independent interest). When m=2 this asymptotic stability may fail: in the case of heat-flow with a further symmetry restriction, we show that more exotic asymptotics are possible, including infinite-time concentration (blow-up), and even "eternal oscillation".Comment: 34 page

Optimizing the growth conditions of Al mirrors for superconducting nanowire single-photon detectors

We investigate the growth conditions for thin (less than 200 nm) sputtered aluminum (Al) films. These coatings are needed for various applications, e.g. for advanced manufacturing processes in the aerospace industry or for nanostructures for quantum devices. Obtaining high-quality films, with low roughness, requires precise optimization of the deposition process. To this end, we tune various sputtering parameters such as the deposition rate, temperature, and power, which enables 50 nm thin films with a root mean square (RMS) roughness of less than 1 nm and high reflectivity. Finally, we confirm the high quality of the deposited films by realizing superconducting single-photon detectors integrated into multi-layer heterostructures consisting of an aluminum mirror and a silicon dioxide dielectric spacer. We achieve an improvement in detection efficiency at 780 nm from 40 % to 70 % by this integration approach.Comment: 11 pages, 6 figure

Charged particle densities from Au+Au collisions at sqrt{s_{NN}}=130 GeV

We present charged particle densities as a function of pseudorapidity and collision centrality for the 197Au+197Au reaction at sqrt{s_{NN}}=130 GeV. An integral charged particle multiplicity of 3860+/-300 is found for the 5% most central events within the pseudorapidity range -4.7 <= eta <= 4.7. At mid-rapidity an enhancement in the particle yields per participant nucleon pair is observed for central events. Near to the beam rapidity, a scaling of the particle yields consistent with the ``limiting fragmentation'' picture is observed. Our results are compared to other recent experimental and theoretical discussions of charged particle densities in ultra-relativistic heavy-ion collisions.Comment: 14 pages, 4 figures; to be published in Phys. Lett.

The experience of providing young people attending general practice with an online risk assessment tool to assess their own sexual health risk

<p>Abstract</p> <p>Background</p> <p>Targeted chlamydia screening has been advocated to reduce chlamydia associated reproductive sequelae. General practitioners are well positioned to play a major role in chlamydia control. The primary aim of this pilot study was to measure the effect of offering an online sexual health assessment tool, <it>Youth Check Your Risk</it>, on chlamydia testing rates among young people attending general practices. The secondary aim was to test the acceptability of the tool among general practitioners and young people.</p> <p>Methods</p> <p>General practitioners at three practices in Melbourne, Australia, referred patients aged 16 to 24 years to <it>Youth Check Your Risk </it><url>http://www.checkyourrisk.org.au</url> for use post-consultation between March to October 2007. The proportion of young people tested for chlamydia before and during the implementation of the tool was compared. Acceptability was assessed through a structured interviewer-administered questionnaire with general practitioners, and anonymous online data provided by <it>Youth Check Your Risk </it>users.</p> <p>Results</p> <p>The intervention did not result in any significant increases in the proportion of 16 to 24 year old males (2.7% to 3.0%) or females (6.3% to 6.4%) tested for chlamydia. A small increase in the proportion of 16 to 19 year old females tested was seen (4.1% to 7.2%). Of the 2997 patients seen during the intervention phase, 871 (29.1%) were referred to <it>Youth Check Your Risk </it>and 120 used it (13.8%). Major reasons for low referral rates reported by practitioners included lack of time, discomfort with raising the issue of testing, and difficulty in remembering to refer patients.</p> <p>Conclusion</p> <p>Offering an online sexual risk assessment tool in general practice did not significantly increase the proportion of young people tested for chlamydia, with GPs identifying a number of barriers to referring young people to <it>Youth Check Your Risk</it>. Future interventions aimed at increasing chlamydia screening in general practice with the aid of an online risk assessment tool need to identify and overcome barriers to testing.</p