5,935 research outputs found

    The Effect of Secret Clock Manipulation on 10 km Cycle Time Trial Performance.

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    The anticipatory RPE feedback model (Tucker 2009) proposes that during self paced exercise tasks, muscular work is continually regulated through comparison of a subconscious ‘template’ Rating of Perceived Exertion (RPE) that serves to protect against the development of catastrophic physiological failure, and a ‘conscious’ RPE that is generated through afferent feedback with regards to peripheral physiological status and through psychological inputs. The aim of this study was to investigate the effect of altering psychological inputs via incorrect time feedback on both RPE and performance during a series of maximal effort 10km cycle time trials. After task familiarisation, eight participants performed three separate time trials using their own cycle mounted onto the Kingcycle ergometer rig. Distance covered was available via large visual display along with elapsed time. On one occasion the display clock ran at the correct speed, but on two other occasions the clock manipulation was altered so that it ran either 10% too fast or 10% too slow. The order of the interventions was randomised. Although no significant differences were observed in total performance time, the magnitude of the endspurt participants were able to generate in the final 10% of the trial was significantly (P<0.01) greater during the slow clock trials than during the fast clock trials. Despite differences in pace distribution under each clock condition, a similar generally linear increase in RPE was observed throughout trials in all conditions. It is proposed that these findings lend support to the anticipatory RPE feedback model, and that altered psychological inputs probably act by influencing the fraction of metabolic reserve capacity that can be accessed during such trials

    A common scheme for running NLO ep event generators

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    In this article we present a generic interface to several next-to-leading order cross-section programs. This enables the user to implement his/her code once and make cross-checks with different programs.Comment: 19 pages, Proceedings of Workshop on Monte Carlo Generators for HERA Physics 1998/9

    Grand Unification and Light Color-Octet Scalars at the LHC

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    We study the properties and production mechanisms of color-octet scalars at the LHC. We focus on the single production of both charged and neutral members of an (8,2)_1/2 doublet through bottom quark initial states. These channels provide a window to the underlying Yukawa structure of the scalar sector. Color-octet scalars naturally appear in grand unified theories based on the SU(5) gauge symmetry. In the context of adjoint SU(5) these fields are expected to be light to satisfy constraints coming from unification and proton decay, and may have TeV-scale masses. One combination of their couplings is defined by the relation between the down-quark and charged-lepton Yukawa couplings. Observation of these states at the LHC gives an upper bound on the proton lifetime if they truly arise from this grand unified theory. We demonstrate that TeV-mass scalars can be observed over background at the LHC using boosted top quark final states, and study how well the scalar Yukawa parameters can be measured.Comment: 22 pages, LaTeX, 5 figures; typos corrected, references adde

    Sialic acid acquisition in bacteria - one substrate many transporters

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    The sialic acids are a family of 9-carbon sugar acids found predominantly on the cell-surface glycans of humans and other animals within the Deuterostomes and are also used in the biology of a wide range of bacteria that often live in association with these animals. For many bacteria sialic acids are simply a convenient source of food, whereas for some pathogens they are also used in immune evasion strategies. Many bacteria that use sialic acids derive them from the environment and so are dependent on sialic acid uptake. In this mini-review I will describe the discovery and characterization of bacterial sialic acids transporters, revealing that they have evolved multiple times across multiple diverse families of transporters, including the ATP-binding cassette (ABC), tripartite ATP-independent periplasmic (TRAP), major facilitator superfamily (MFS) and sodium solute symporter (SSS) transporter families. In addition there is evidence for protein-mediated transport of sialic acids across the outer membrane of Gram negative bacteria, which can be coupled to periplasmic processing of different sialic acids to the most common form, β-D-N-acetylneuraminic acid (Neu5Ac) that is most frequently taken up into the cell

    DEVELOPMENT OF A LOW PRESSURE-INDUCTIVELY COUPLED PLASMA-ION SOURCE FOR MASS SPECTROMETRY

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    A low pressure-inductively coupled plasma (LP-ICP) ion source has been investigated for the production of atomic and molecular ions for mass spectrometry (MS). A dedicated LPICP- MS was constructed, by modifying a Hewlett Packard mass selective detector, to detect ions from the LP-ICP. The ion sampling interface and ion optics were designed using established theory and the use of a computer simulation program. Perfluorotributylamine was continuously introduced into the LP-ICP, via a molecular leak, and the ion sampling interface, plasma forward power, and plasma gas flow rates, were optimised. When the LP-ICP ion source was sustained at 6W with a gas flow of 6 ml min'* helium, and iodobenzene and dibromobenzene, introduced via GC, only atomic signals for iodine and bromine were observed. Detection limits were 4 and 76 pg for iodobenzene and dibromobenzene respectively. The addition of nitrogen to a LP helium ICP increased the molecular signal for chlorobenzene, resulting in a detection limit of 2 pg. However, the addition of nitrogen did not aid the production of molecular ions of iodobenzene and dibromobenzene. When 0.07 ml min' of isobuiane was added to the LP-ICP mass spectra similar to those obtained by an electron impact source were observed. However, on the addition of more isobutane only the molecular ions (M*) for chlorobenzene, iodobenzene and dibromobenzene were observed. The detection limits for the instrument operating in the molecular mode were 100, 140 and 229 pg for chlorobenzene, iodobenzene and dibromobenzene respectively. Langmuir probe measurements were used to asses the effect of plasma forward power and gas flow rate on the local plasma potential, ion number density, electron temperature and electron number density within the LP-ICP. The local plasma potential varied from +50 V to -20 V depending on the plasma conditions used. The ion and electron number densities increased with increasing plasma power, with ion number densities of approximately 10^ cm' ^ and electron number densities of approximately at 10* cm ^ The effect of extra plasma gas had a less distinct affect on the plasma excited species. A plasma sustained at 6 W, 7 ml min'' helium and 1.8 ml min'* isobutane was used to provide both quantitative and qualitative information of tetraethyllead in the standard reference friel (NBS SRM 1637 II), with .the determined value of 13.06 ± 0.91 being in good agreement with the certified value of 12.9 ± 0.07 expressed as total lead.British Petroleum International, Sunbury-on-Thames, Middlesex, TW16 7L

    Discussant\u27s response to \u27Under the spreading chestnut tree,\u27 accountants\u27 legal liability -- A historical perspective

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    https://egrove.olemiss.edu/dl_proceedings/1173/thumbnail.jp

    Resonance Searches with an Updated Top Tagger

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    The performance of top taggers, for example in resonance searches, can be significantly enhanced through an increased set of variables, with a special focus on final-state radiation. We study the production and the decay of a heavy gauge boson in the upcoming LHC run. For constant signal efficiency, the multivariate analysis achieves an increased background rejection by up to a factor 30 compared to our previous tagger. Based on this study and the documentation in the Appendix we release a new HEPTopTagger2 for the upcoming LHC run. It now includes an optimal choice of the size of the fat jet, N-subjettiness, and different modes of Qjets.Comment: 26 page
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