Thermocapillary manipulation of droplets using holographic beam shaping: Microfluidic pin ball

International audienceWe demonstrate that holographically generated optical patterns offer greater flexibility for the thermocapillary control of water droplets than Gaussian spots; droplets can be stopped in faster flows while using less optical intensity when the surface tension variations are created by line patterns instead of single spots. Further, experiments are performed making use of variable light patterns to achieve controlled droplet routing in a four-way cross microfluidic channel. Finally, multiple droplet storage is demonstrated as well as changing drop order. © 2008 American Institute of Physics

An explicit height bound for the classical modular polynomial

For a prime m, let Phi_m be the classical modular polynomial, and let h(Phi_m) denote its logarithmic height. By specializing a theorem of Cohen, we prove that h(Phi_m) <= 6 m log m + 16 m + 14 sqrt m log m. As a corollary, we find that h(Phi_m) <= 6 m log m + 18 m also holds. A table of h(Phi_m) values is provided for m <= 3607.Comment: Minor correction to the constants in Theorem 1 and Corollary 9. To appear in the Ramanujan Journal. 17 pages

Reach in and reach out : the story of the MSc in pipeline engineering at Newcastle University

This paper presents an unusual case of university-industry interaction whereby a group of small businesses came together to persuade a university to establish an MSc in Pipeline Engineering. We identify that the course contributed to regional development in four ways. Firstly, it provided graduates for local industry. Secondly, it linked local firms with pipeline engineers world wide and raised the region's profile within that network. Thirdly, it strengthened the research base of the university through the recruitment of pipeline engineers from industry and fourthly, it facilitated the possibility of joint research between the university and local firms. We question whether this model is transferable to other industry sectors/universities. We conclude that this outreach activity has been shaped by the 'reach-in' to the university of the local business community and propose a revised model of university interaction with regional industry. Traditionally universities have been seen as 'reaching out' to regional industry and the collaborations have been viewed as being instigated by the university and often research-based. Our revised model proposes an alternative mechanism whereby collaborations can be instigated by industry and through a teaching-route

Competing risks and deposit insurance governance convergence

Why do policies often seem to converge across countries at the same time? This question has been studied extensively in the diffusion literature. However, past research has not examined complex choice environments, especially where there are many alternatives. This article fills this gap in the literature. I show how Fine and Gray's Competing Risks Event History Analysis can be used to tease apart the causes of policy convergence. I apply the method to an examination of the reasons why, from the mid-1990s to 2007, many countries created independent deposit insurers. I find an interaction between international recommendations and regional peers' choices, particularly in the European Union. However, convergence appears to slow under the particular conditions of a banking crisis, regardless of how well independence is promoted. Possibly due to electoral incentives, democracies seem to have been more likely to create independent insurers. Ultimately, I demonstrate how competing risks analysis can help enable future research on policy choices, complementing methods previously applied in political economy. © The Author(s) 2013

Flavour and Collider Interplay for SUSY at LHC7

The current 7 TeV run of the LHC experiment shall be able to probe gluino and squark masses up to values larger than 1 TeV. Assuming that hints for SUSY are found in the jets plus missing energy channel by the end of a 5 fb$^{-1}$ run, we explore the flavour constraints on three models with a CMSSM-like spectrum: the CMSSM itself, a Seesaw extension of the CMSSM, and Flavoured CMSSM. In particular, we focus on decays that might have been measured by the time the run is concluded, such as $B_s\to\mu\mu$ and $\mu\to e\gamma$. We also analyse constraints imposed by neutral meson bounds and electric dipole moments. The interplay between collider and flavour experiments is explored through the use of three benchmark scenarios, finding the flavour feedback useful in order to determine the model parameters and to test the consistency of the different models.Comment: 44 pages, 15 figures; v3: minor corrections, added references, updated figures. Version accepted for publicatio

Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt(s)=1.96 TeV using Lepton + Jets Events with Lifetime b-tagging

We present a measurement of the top quark pair ($t\bar{t}$) production cross section ($\sigma_{t\bar{t}}$) in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV using 230 pb$^{-1}$ of data collected by the D0 experiment at the Fermilab Tevatron Collider. We select events with one charged lepton (electron or muon), missing transverse energy, and jets in the final state. We employ lifetime-based b-jet identification techniques to further enhance the $t\bar{t}$ purity of the selected sample. For a top quark mass of 175 GeV, we measure $\sigma_{t\bar{t}}=8.6^{+1.6}_{-1.5}(stat.+syst.)\pm 0.6(lumi.)$ pb, in agreement with the standard model expectation.Comment: 7 pages, 2 figures, 3 tables Submitted to Phys.Rev.Let

BB flavour tagging using charm decays at the LHCb experiment

An algorithm is described for tagging the flavour content at production of neutral $B$ mesons in the LHCb experiment. The algorithm exploits the correlation of the flavour of a $B$ meson with the charge of a reconstructed secondary charm hadron from the decay of the other $b$ hadron produced in the proton-proton collision. Charm hadron candidates are identified in a number of fully or partially reconstructed Cabibbo-favoured decay modes. The algorithm is calibrated on the self-tagged decay modes $B^+ \to J/\psi \, K^+$ and $B^0 \to J/\psi \, K^{*0}$ using $3.0\mathrm{\,fb}^{-1}$ of data collected by the LHCb experiment at $pp$ centre-of-mass energies of $7\mathrm{\,TeV}$ and $8\mathrm{\,TeV}$. Its tagging power on these samples of $B \to J/\psi \, X$ decays is $(0.30 \pm 0.01 \pm 0.01) \%$.Comment: All figures and tables, along with any supplementary material and additional information, are available at http://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-027.htm

Evidence for the strangeness-changing weak decay Ξb−→Λb0π−\Xi_b^-\to\Lambda_b^0\pi^-

Using a $pp$ collision data sample corresponding to an integrated luminosity of 3.0~fb$^{-1}$, collected by the LHCb detector, we present the first search for the strangeness-changing weak decay $\Xi_b^-\to\Lambda_b^0\pi^-$. No $b$ hadron decay of this type has been seen before. A signal for this decay, corresponding to a significance of 3.2 standard deviations, is reported. The relative rate is measured to be ${{f_{\Xi_b^-}}\over{f_{\Lambda_b^0}}}{\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-) = (5.7\pm1.8^{+0.8}_{-0.9})\times10^{-4}$, where $f_{\Xi_b^-}$ and $f_{\Lambda_b^0}$ are the $b\to\Xi_b^-$ and $b\to\Lambda_b^0$ fragmentation fractions, and ${\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-)$ is the branching fraction. Assuming $f_{\Xi_b^-}/f_{\Lambda_b^0}$ is bounded between 0.1 and 0.3, the branching fraction ${\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-)$ would lie in the range from $(0.57\pm0.21)\%$ to $(0.19\pm0.07)\%$.Comment: 7 pages, 2 figures, All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-047.htm

Spinal epidural abscess: a rare complication of olecranon bursitis

Spinal epidural abscess is a rare but potentially fatal condition if left untreated. We report the case of a 67-year old man who presented to the Accident and Emergency department complaining of acute onset of inter-scapular back pain, left leg weakness and loss of sensation in the left foot. On examination he was found to be pyrexial with long tract signs in the left lower leg. In addition he had a left sided olecranon bursitis of three weeks duration. Blood tests revealed raised inflammatory markers and a staphylococcal bacteremia. Magnetic resonance imaging (MRI) confirmed the diagnosis of spinal epidural abscess and he subsequently underwent a three level laminectomy with good resolution of his back pain and neurological symptoms. He has made a complete recovery with a prolonged course of intravenous antibiotics