Measurements of heavy-flavour production in p-Pb collisions with ALICE

The production of open heavy-flavour particles was studied in p-Pb collisions at $\sqrt{s_\mathrm{NN}}=5.02$ TeV using the ALICE detector. Three separate observables were used: the hadronic decays of D mesons at mid-rapidity, and semileptonic decays of heavy-flavour hadrons to electrons and muons at mid-rapidity and forward rapidity, respectively. The most recent ALICE measurements of the nuclear modification factor, $R_\mathrm{pPb}$, of open charm and beauty are reported, along with the centrality and multiplicity dependence of D-meson production in p-Pb collisions.Comment: 4 pages, 10 figures. To appear in proceedings of Quark Matter 2015, Kobe, Japa

Mid-rapidity D-meson production in pp, Pb-Pb and p-Pb collisions at the LHC

We present the recent results for D-meson production measured by the ALICE collaboration in pp collisions at $\sqrt{s}=7$ TeV, Pb-Pb collisions at $\sqrt{s_\mathrm{NN}}=2.76$ TeV and p-Pb collisions at $\sqrt{s_\mathrm{NN}}=5.02$ TeV.Comment: 8 pages, 10 figures. Proceedings of the 9th International Workshop on High-pT Physics at LHC, LPSC Grenoble, France, 24-28 September 201

Why social scientists should engage with natural scientists

It has become part of the mantra of contemporary science policy that the resolution of besetting problems calls for the active engagement of a wide range of sciences. The paper reviews some of the key challenges for those striving for a more impactful social science by engaging strategically with natural scientists. It argues that effective engagement depends upon overcoming basic assumptions that have structured past interactions: particularly, the casting of social science in an end-of-pipe role in relation to scientific and technological developments. These structurings arise from epistemological assumptions about the underlying permanence of the natural world and the role of science in uncovering its fundamental order and properties. While the impermanence of the social world has always put the social sciences on shakier foundations, twenty-first century concerns about the instability of the natural world pose different epistemological assumptions that summon a more equal, immediate and intense interaction between field and intervention oriented social and natural scientists. The paper examines a major research programme that has exemplified these alternative epistemological assumptions. Drawing on a survey of researchers and other sources it seeks to draw out the lessons for social/natural science cross-disciplinary engagement

Quantifying simulator discrepancy in discrete-time dynamical simulators

When making predictions with complex simulators it can be important to quantify the various sources of uncertainty. Errors in the structural specification of the simulator, for example due to missing processes or incorrect mathematical specification, can be a major source of uncertainty, but are often ignored. We introduce a methodology for inferring the discrepancy between the simulator and the system in discrete-time dynamical simulators. We assume a structural form for the discrepancy function, and show how to infer the maximum likelihood parameter estimates using a particle filter embedded within a Monte Carlo expectation maximization (MCEM) algorithm. We illustrate the method on a conceptual rainfall runoff simulator (logSPM) used to model the Abercrombie catchment in Australia. We assess the simulator and discrepancy model on the basis of their predictive performance using proper scoring rules

Analysis of D0 and D*+-meson production in pp and p-Pb collisions with ALICE at the LHC

This thesis presents measurements of D-meson production in the central barrel of the ALICE detector in pp and p-Pb collisions. The reconstruction of D0 mesons in the hadronic channel D0 -> K- pi+ was studied in pp collisions at sqrt(s) = 7 TeV using a Bayesian particle identification (PID) method, in order to test the validity of this new approach. Comparisons were made between these results and those obtained with established PID methods. Consistency was found between the different approaches, as well as an increase of the signal-to-background ratio and a similar or greater statistical significance for most of the implementations of the Bayesian approach. Further measurements of D*+ -> D0 pi+ were made as a function of charged-particle multiplicity in p-Pb collisions at sqrt(sNN) = 5.02 TeV. The aim was to test the role of multi-parton interactions (MPI) and possible collective phenomena in small systems at LHC energies. The results for D*+ mesons were consistent with the other D-meson species studied by ALICE (D0 and D+). The measurements against mid-rapidity multiplicity showed consistency with previous results from pp collisions; however, a slower increase of the relative D-meson yield was found as a function of multiplicity at large rapidity for p-Pb collisions than pp collisions. The results for both multiplicity estimators were reproduced by phenomenological models, both with and without viscous hydrodynamics

Surface biotinylation of primary neurons to monitor changes in AMPA receptor surface expression in response to kainate receptor stimulation

Here, we detail a surface biotinylation technique used to label surface-expressed proteins in primary neuronal cultures. Surface proteins are labeled with membrane-impermeant Sulfo-NHS-SS-biotin, and isolated by pull-down with streptavidin beads followed by western blotting to measure levels of surface expression of the protein of interest under different conditions. We have used this approach extensively to monitor activity-dependent changes in α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) and kainate receptor (KAR) subunits. However, this protocol can be used to investigate any surface-expressed protein. For complete details on the use and execution of this protocol, please refer to Nair et al. (2021)