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

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

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

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

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

Resonance Searches with an Updated Top Tagger

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

Constraints and Opportunities in GCM Model Development

Over the past 30 years climate models have evolved from relatively simple representations of a few atmospheric processes to complex multi-disciplinary system models which incorporate physics from bottom of the ocean to the mesopause and are used for seasonal to multi-million year timescales. Computer infrastructure over that period has gone from punchcard mainframes to modern parallel clusters. Constraints of working within an ever evolving research code mean that most software changes must be incremental so as not to disrupt scientific throughput. Unfortunately, programming methodologies have generally not kept pace with these challenges, and existing implementations now present a heavy and growing burden on further model development as well as limiting flexibility and reliability. Opportunely, advances in software engineering from other disciplines (e.g. the commercial software industry) as well as new generations of powerful development tools can be incorporated by the model developers to incrementally and systematically improve underlying implementations and reverse the long term trend of increasing development overhead. However, these methodologies cannot be applied blindly, but rather must be carefully tailored to the unique characteristics of scientific software development. We will discuss the need for close integration of software engineers and climate scientists to find the optimal processes for climate modeling

Ensemble-induced strong light-matter coupling of a single quantum emitter

We discuss a technique to strongly couple a single target quantum emitter to a cavity mode, which is enabled by virtual excitations of a nearby mesoscopic ensemble of emitters. A collective coupling of the latter to both the cavity and the target emitter induces strong photon non-linearities in addition to polariton formation, in contrast to common schemes for ensemble strong coupling. We demonstrate that strong coupling at the level of a single emitter can be engineered via coherent and dissipative dipolar interactions with the ensemble, and provide realistic parameters for a possible implementation with SiV$^{-}$ defects in diamond. Our scheme can find applications, amongst others, in quantum information processing or in the field of cavity-assisted quantum chemistry.Comment: 13 pages, 6 figures; substantially revised manuscript; see arXiv:1912.12703 for mathematical derivation