Maser radiation from collisionless shocks

Funding: UK Engineering and Physical Sciences Research Council (grant Nos. EP/N014472/1, EP/R004773/1 and EP/N013298/1) and the Science and Technologies Facilities Council of the United Kingdom. F.C. and L.O.S. acknowledge support from the European Research Council (InPairs ERC-2015-AdG 695088) and FCT Portugal (grant No. PD/BD/114307/2016).This paper describes a model of electron energization and cyclotron-maser emission applicable to astrophysical magnetized collisionless shocks. It is motivated by the work of Begelman, Ergun and Rees [Astrophys. J. 625 , 51 (2005)] who argued that the cyclotron-maser instability occurs in localized magnetized collisionless shocks such as those expected in blazar jets. We report on recent research carried out to investigate electron acceleration at collisionless shocks and maser radiation associated with the accelerated electrons. We describe how electrons accelerated by lower-hybrid,waves at collisionless shocks generate cyclotron-maser radiation when the accelerated electrons move into regions of stronger magnetic fields. The electrons are accelerated along the magnetic field and magnetically compressed leading to the formation of an electron velocity distribution having a horseshoe shape due to conservation of the electron magnetic moment. Under certain conditions the horseshoe electron velocity distribution function is unstable to the cyclotron-maser instability [Bingham and Cairns, Phys. Plasmas 7, 3089 (2000); Melrose, Rev. Mod. Plasma Phys. 1 , 5 (2017)].Publisher PDFPeer reviewe

T2K ECAL Test–beam Proposal

The T2K experiment will search for the last unknown element of the neutrino mixing matrix. An crucial component of the near detector for this experiment is the electromagnetic calorimeter which is being built in the UK. Testbeam time is requested to test the full ECAL system, validate calibration techniques, and determine the hadronic and electromagnetic energy scale of the calorimeter

The electromagnetic calorimeter for the T2K near detector ND280

The T2K experiment studies oscillations of an off-axis muon neutrino beam between the J-PARC accelerator complex and the Super-Kamiokande detector. Special emphasis is placed on measuring the mixing angle θ 13 by observing ν e appearance via the sub-dominant νμ ν e oscillation and searching for CP violation in the lepton sector. The experiment includes a sophisticated, off-axis, near detector, the ND280, situated 280 m downstream of the neutrino production target in order to measure the properties of the neutrino beam and to understand better neutrino interactions at the energy scale below a few GeV. The data collected with the ND280 are used to study charged- and neutral-current neutrino interaction rates and kinematics prior to oscillation, in order to reduce uncertainties in the oscillation measurements by the far detector. A key element of the near detector is the ND280 electromagnetic calorimeter (ECal), consisting of active scintillator bars sandwiched between lead sheets and read out with multi-pixel photon counters (MPPCs). The ECal is vital to the reconstruction of neutral particles, and the identification of charged particle species. The ECal surrounds the Pi-0 detector (PØD) and the tracking region of the ND280, and is enclosed in the former UA1/NOMAD dipole magnet. This paper describes the design, construction and assembly of the ECal, as well as the materials from which it is composed. The electronic and data acquisition (DAQ) systems are discussed, and performance of the ECal modules, as deduced from measurements with particle beams, cosmic rays, the calibration system, and T2K data, is described.© 2013 IOP Publishing Ltd and Sissa Medialab srl.The ECal detector has been built and is operated using funds provided by the Science and Technology Facilities Council U.K. Important support was also provided by the collaborating institutions. Individual researchers have been supported by the Royal Society and the European Research Council

Hydration kinetics and 10-km outdoor running performance following 75% versus 150% between bout fluid replacement

© 2014, © 2014 European College of Sport Science. Abstract: Current American College of Sports Medicine (ACSM) guidelines recommend replacing 150% of sweat losses between training bouts separated by ≤12 hours, but little evidence exists concerning the implications of this strategy for runners. Participants (n = 13) in this study replaced 75% (1637 ± 372 mL) or 150% (3099 ± 850 mL) of sweat losses following an outdoor evening run (∼75 minutes; Wet-bulb-globe temperature (WBGT) = ∼27°C) and consumed a standardised evening meal and breakfast before completing an outdoor (WBGT = ∼23°C) 10-km time-trial the following morning. Urine was collected between runs and urine specific gravity (USG) was assessed pre-run. Significant differences were found in pre-run body mass (75% = 69.6 ± 9.2; 150% = 70.1 ± 9.3 kg; P = 0.02) and USG (75% = 1.026 ± 0.005; 150% = 1.014 ± 0.007; P \u3c 0.001). Heart rate during 10-km run (168 ± 14 versus 168 ± 12 beats min−1) and post-run intestinal temperature (39.08 ± 0.52 versus 39.00 ± 0.70 °C) did not differ for 75% and 150%, respectively, despite an ∼3% performance improvement (75% = 47.28 ± 6.64; 150% = 45.93 ± 6.04 minutes; P = 0.001) due to a faster pace in the second half of the run with 150% replacement. Session rate of perceived exertion (RPE) was lower (P = 0.02) during 150% (7.5 ± 1.3) versus 75% (8.4 ± 0.9). Reluctant drinkers potentially hinder training quality between evening and morning runs in the heat, but copious urine production and difficulty in consuming recommended fluid volumes suggest fluid replacement \u3c150% may be more ideal

Qualidade de vida de pacientes submetidos a cirurgia de epilepsia Quality of life after epilepsy surgery

Epilepsia refratária ao tratamento medicamentoso é condição que interfere direta e negativamente na qualidade de vida dos pacientes, dificultando-lhes principalmente a integração social. O tratamento cirúrgico tem se mostrado eficaz no controle das crises em casos refratários, ocupando lugar importante no tratamento das epilepsias. Avaliamos a qualidade de vida de pacientes epilépticos, antes e após o tratamento cirúrgico, através de um questionário sobre qualidade de vida, adaptado do QOLIE-10 aplicado em 12 indivíduos epilépticos adultos, operados consecutivamente. O questionário, com 10 perguntas, envolvendo aspectos psicossociais e relacionados às drogas antiepilépticas, foi respondido no período pré-cirúrgico e repetido num intervalo médio de 8 meses após a cirurgia. Na comparação do questionário no período pré-operatório com o período pós-operatório, observamos diferenças estatisticamente significantes em 70% das perguntas, mostrando melhora da qualidade de vida após a cirurgia. Nestes casos, a terapêutica cirúrgica tem forte impacto na qualidade de vida.<br>Drug resistant epilepsy impairs patients' quality of life making social interaction more difficult. Surgical treatment is an option for seizure control in medically refractory patients. We evaluated pre-operative and post-operative quality of life using a standardized questionnaire based on the QOLIE-10. The questionnaire included ten questions dealing with psychosocial and drug's side effects and was applied before surgery and eight months post-operatively. The studied sample comprised twelve consecutive adult patients with epilepsy treated surgically who were seizure free. Differences were found between the pre-operative and post-operative periods in 70% of the questions, with a better post-operative profile. Successful epilepsy surgery has a great impact in the quality of life of these patients

‘Just teach us the skills please, we’ll do the rest': empowering ten-year-olds as active researchers

This paper discusses the outcomes of an initiative to empower ten-year-olds as active researchers. It debates some of the barriers that are commonly cited with regard to children of this age taking ownership of their own research agendas—power relations, competence, knowledge and skills—and challenges the status quo. It describes a study in which a group of ten-year-olds participated in a taught programme aimed at equipping them with the knowledge and skills to design their own research. This empowering process resulted in the children undertaking research projects of their own choosing, designed, carried out and reported entirely from their perspective. Reports from two of those projects are presented as part of this paper

The T2K experiment

The T2K experiment is a long baseline neutrino oscillation experiment. Its main goal is to measure the last unknown lepton sector mixing angle θ13 by observing νe appearance in a νμ beam. It also aims to make a precision measurement of the known oscillation parameters, and sin22θ23, via νμ disappearance studies. Other goals of the experiment include various neutrino cross-section measurements and sterile neutrino searches. The experiment uses an intense proton beam generated by the J-PARC accelerator in Tokai, Japan, and is composed of a neutrino beamline, a near detector complex (ND280), and a far detector (Super-Kamiokande) located 295 km away from J-PARC. This paper provides a comprehensive review of the instrumentation aspect of the T2K experiment and a summary of the vital information for each subsystem