Role of p21 activated kinase in zebrafish lateral line development.

Migration of the posterior lateral line primordium is a process of directed response to a chemotactic signal. We have observed directional protrusions of the cells at the leading edge of migrating primordia. The p21 activated kinase (Pak) family of proteins are downstream effectors of the small GTPases Rac and Cdc42 and have been shown to play important roles in the regulation of cell adhesion and migration in many organisms. In order to understand the molecular mechanisms underlying directed cell migration in zebrafish we have identified and characterised two zebrafish pak2 genes {lcub}pak2a and pak2b) and found that their functions are important for migration of the lateral line primordium. Pak2a and Pak2b have similar protein sequences suggesting similar functions in development. Knock down of Pak2 using antisense morpholino oligonucleotides resulted in a variety of defects in zebrafish development including retarded migration of the posterior lateral line primordium and aberrant migration of primordial germ cells. Zebrafish pak2 genes may function by dynamically regulating the F-actin reorganisation and focal adhesion formation required for directed migration. Differences in the phenotypes generated by knock down of Pak2a and Pak2b may be explained in part by the observation that Pak2a can bind to the adaptor protein Nek while Pak2b cannot. Pak2b is required to establish and/or maintain F-actin organisation, cadherin- mediated adhesion and tissue integrity within the migrating lateral line primordium. We show that dynamic regulation of the actin cytoskeleton and cell adhesion is involved in the formation of rosette-like structures within the lateral line primordium which are deposited as a unit and represent the nascent neuromast precursors. We have also identified possible roles for Pak2a and Pak2b in regulating gene expression in early zebrafish development. Pak2 proteins may control the expression of several genes involved in mesoderm formation through regulation of transcriptional activators and repressors

New constructions of twistor lifts for harmonic maps

We show that given a harmonic map $\varphi$ from a Riemann surface to a classical compact simply connected inner symmetric space, there is a $J_2$-holomorphic twistor lift of $\varphi$ (or its negative) if and only if it is nilconformal. In the case of harmonic maps of finite uniton number, we give algebraic formulae in terms of holomorphic data which describes their extended solutions. In particular, this gives explicit formulae for the twistor lifts of all harmonic maps of finite uniton number from a surface to the above symmetric spaces.Comment: Some minor changes and a correction of Example 8.

Health providers as bricoleurs:an examination of the adaption of health ecosystems to superdiversity in Europe

This article examines the ways in which healthcare providers from a mixed economy of welfare operating in superdiverse neighbourhoods connect and innovate across the healthcare ecosystem to meet diverse and complex needs. Moving beyond a health systems approach which siloes different types of provision, we use the concept of bricolage to make visible the work undertaken by providers across the ecosystem. While we show that public, private and civil society provision all adapt to meet complex and diverse needs to some degree, we highlight the importance of inter-connectedness between providers and note the role of civil society in addressing gaps and cracks in provision. The importance of adopting a whole ecosystem approach and focusing on the actions and interactions which enable the ecosystem to function in complex demographic environments is highlighted before we stress the dangers of over-reliance on civil society.info:eu-repo/semantics/acceptedVersio

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

Legal, medical and lay understanding of embryos in Portugal: alignment with biology?

Pretende-se contribuir para o debate em torno dos processos de circulação de conhecimentos e sentidos entre especialistas e “leigos” no que concerne ao estatuto dos embriões humanos em Portugal. Reflete-se sobre as expectativas e preocupações manifestadas quanto à confiança, qualidade, segurança e eficácia das tecnologias médicas de reprodução assistida. O estudo assenta na realização de entrevistas individuais, com vistas a explorar as complexidades, similitudes e diferenças entre as visões e os valores de juristas, médicos e casais envolvidos em tratamentos de fertilização in vitro. Trata-se de uma análise qualitativa em um estudo de caso. Se os juristas e os médicos enquadram o estatuto dos embriões em categorias de índole biológica, técnica e/ou jurídico-legal, já os casais estabelecem com os mesmos diversas relações ontológicas de índole moral, afetiva e social, pelo que estes podem ser representados como seres éticos face à biologização médico-legal dos embriões.Our aim is to contribute towards the debate about the processes through which knowledge and meanings regarding the status of human embryos circulate among experts and laymen in Portugal. Expectations and concerns expressed regarding the reliability, quality, safety and efficacy of medical technologies for assisted reproduction were assessed. This study is based on data from individual interviews that sought to explore the complexities, similarities and differences among the views and values of jurists, doctors and couples involved in in vitro fertilization treatments. It consists of a qualitative analysis on a case study. If jurists and doctors frame the status of embryos as categories of a biological, technical and/or legal nature, couples establish between themselves a variety of ontological relationships of a moral, affective and social nature. Through these, they can be represented as ethical beings, thus contrasting with the medical-legal biologization of the embryos.To the jurists, doctors and women and men who we interviewed and who shared with us their views and experiences, our sincere thanks. We also thank Helena Lima and Filomena Louro (Scientific Editing Programme, University of Minho) for the translation of the Portuguese text into English; and the revision of David George Elliff. The authors thank the Foundation for Science and Technology (Portuguese Ministry of Science, Technology and Higher Education) for the financial support for this research, through a PhD fellowship (SFRH/BD/10396/2002) and a post-doctoral fellowship (SFRH/BPD/47020/2008).info:eu-repo/semantics/publishedVersio

Measurement of event-shape observables in Z→ℓ+ℓ− events in pp collisions at √ s=7 TeV with the ATLAS detector at the LHC

Event-shape observables measured using charged particles in inclusive $Z$-boson events are presented, using the electron and muon decay modes of the $Z$ bosons. The measurements are based on an integrated luminosity of $1.1 {\rm fb}^{-1}$ of proton--proton collisions recorded by the ATLAS detector at the LHC at a centre-of-mass energy $\sqrt{s}=7$ TeV. Charged-particle distributions, excluding the lepton--antilepton pair from the $Z$-boson decay, are measured in different ranges of transverse momentum of the $Z$ boson. Distributions include multiplicity, scalar sum of transverse momenta, beam thrust, transverse thrust, spherocity, and $\mathcal{F}$-parameter, which are in particular sensitive to properties of the underlying event at small values of the $Z$-boson transverse momentum. The Sherpa event generator shows larger deviations from the measured observables than Pythia8 and Herwig7. Typically, all three Monte Carlo generators provide predictions that are in better agreement with the data at high $Z$-boson transverse momenta than at low $Z$-boson transverse momenta and for the observables that are less sensitive to the number of charged particles in the event.Comment: 36 pages plus author list + cover page (54 pages total), 14 figures, 4 tables, submitted to EPJC, All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2014-0

Measurement of the cross section for isolated-photon plus jet production in pp collisions at √s=13 TeV using the ATLAS detector

The dynamics of isolated-photon production in association with a jet in proton–proton collisions at a centre-of-mass energy of 13 TeV are studied with the ATLAS detector at the LHC using a dataset with an integrated luminosity of 3.2 fb−1. Photons are required to have transverse energies above 125 GeV. Jets are identified using the anti- algorithm with radius parameter and required to have transverse momenta above 100 GeV. Measurements of isolated-photon plus jet cross sections are presented as functions of the leading-photon transverse energy, the leading-jet transverse momentum, the azimuthal angular separation between the photon and the jet, the photon–jet invariant mass and the scattering angle in the photon–jet centre-of-mass system. Tree-level plus parton-shower predictions from Sherpa and Pythia as well as next-to-leading-order QCD predictions from Jetphox and Sherpa are compared to the measurements

Measurement of the View the tt production cross-section using eμ events with b-tagged jets in pp collisions at √s = 13 TeV with the ATLAS detector

This paper describes a measurement of the inclusive top quark pair production cross-section (σtt¯) with a data sample of 3.2 fb−1 of proton–proton collisions at a centre-of-mass energy of √s = 13 TeV, collected in 2015 by the ATLAS detector at the LHC. This measurement uses events with an opposite-charge electron–muon pair in the final state. Jets containing b-quarks are tagged using an algorithm based on track impact parameters and reconstructed secondary vertices. The numbers of events with exactly one and exactly two b-tagged jets are counted and used to determine simultaneously σtt¯ and the efficiency to reconstruct and b-tag a jet from a top quark decay, thereby minimising the associated systematic uncertainties. The cross-section is measured to be: σtt¯ = 818 ± 8 (stat) ± 27 (syst) ± 19 (lumi) ± 12 (beam) pb, where the four uncertainties arise from data statistics, experimental and theoretical systematic effects, the integrated luminosity and the LHC beam energy, giving a total relative uncertainty of 4.4%. The result is consistent with theoretical QCD calculations at next-to-next-to-leading order. A fiducial measurement corresponding to the experimental acceptance of the leptons is also presented