1,152 research outputs found
Ocular attention-sensing interface system
The purpose of the research was to develop an innovative human-computer interface based on eye movement and voice control. By eliminating a manual interface (keyboard, joystick, etc.), OASIS provides a control mechanism that is natural, efficient, accurate, and low in workload
Emergent phenomena from centre vortices
Quark confinement is perhaps the most important emergent property of the
theory of quantum chromodynamics. Herein we review some key aspects of centre
vortices in SU(3) lattice gauge theory. Starting from the original Monte Carlo
gauge fields, a vortex identification procedure yields vortex-removed and
vortex-only backgrounds. The comparison between the original `untouched' Monte
Carlo gauge fields and these so called vortex-modified ensembles has provided a
variety of results that support the notion that centre vortices are fundamental
to confinement in pure gauge theory. For the first time we perform direct
numerical tests of the response of centre vortices to the presence of dynamical
quarks in SU(3).Comment: 9 pages, 5 figures; Proceedings of 38th International Symposium on
Lattice Field Theory (LATTICE2021), 26-30 July 2021, Zoom/Gather@MIT, US
The curious case of large-N expansions on a (pseudo)sphere
We elucidate the large-N dynamics of one-dimensional sigma models with
spherical and hyperbolic target spaces and find a duality between the Lagrange
multiplier and the angular momentum. In the hyperbolic model we propose a new
class of operators based on the irreducible representations of hyperbolic
space. We also uncover unexpected zero modes which lead to the double scaling
of the 1/N expansion and explore these modes using Gelfand-Dikiy equations.Comment: 18 pages, 3 figure
Targeted interventions for patellofemoral pain syndrome (TIPPS): classification of clinical subgroups
Introduction Patellofemoral pain (PFP) can cause significant pain leading to limitations in societal participation and physical activity. An international expert group has highlighted the need for a classification system to allow targeted intervention for patients with PFP; we have developed a work programme systematically investigating this. We have proposed six potential subgroups: hip abductor weakness, quadriceps weakness, patellar hypermobility, patellar hypomobility, pronated foot posture and lower limb biarticular muscle tightness. We could not uncover any evidence of the relative frequency with which patients with PFP fell into these subgroups or whether these subgroups were mutually exclusive. The aim of this study is to provide information on the clinical utility of our classification system.
Methods and analysis 150 participants will be recruited over 18 months in four National Health Services (NHS) physiotherapy departments in England. Inclusion criteria: adults 18–40 years with PFP for longer than 3 months, PFP in at least two predesignated functional activities and PFP elicited by clinical examination. Exclusion criteria: prior or forthcoming lower limb surgery; comorbid illness or health condition; and lower limb training or pregnancy. We will record medical history, demographic details, pain, quality of life, psychomotor movement awareness and knee temperature. We will assess hip abductor and quadriceps weakness, patellar hypermobility and hypomobility, foot posture and lower limb biarticular muscle tightness.
The primary analytic approach will be descriptive. We shall present numbers and percentages of participants who meet the criteria for membership of (1) each of the subgroups, (2) none of the subgroups and (3) multiple subgroups. Exact (binomial) 95% CIs for these percentages will also be presented.
Ethics and dissemination This study has been approved by National Research Ethics Service (NRES) Committee North West—Greater Manchester North (11/NW/0814) and University of Central Lancashire (UCLan) Built, Sport, Health (BuSH) Ethics Committee (BuSH 025). An abstract has been accepted for the third International Patellofemoral Pain Research Retreat, Vancouver, September 2013
Suspended particulates at the Point Loma, California wastewater outfall
A recent study conducted at the Point Loma wastewater outfall in San Diego used a novel sampling technique, the Pelagic Laser Tomographer (PLT), in combination with traditional water column profiling instruments to analyze suspended particulate distributions and effluent plume dynamics. Coastal wastewater discharges create buoyant plumes that interact with the surrounding water, and the tracking and mapping of the resulting diluted effluent is essential for monitoring outfall system performance. The results from the PLT sampling highlight the utility of high spatial and temporal resolution estimates of suspended particulate size spectra to help capture the dynamics of the plume interactions with the coastal current flow field. In addition, new tools like the PLT can help marine scientists estimate natural and anthropogenic particulate size distributions that are essential to our understanding sediment and pollutant transport, nutrient cycling, and ecosystem energy dynamics
Qudit Quantum State Tomography
Recently quantum tomography has been proposed as a fundamental tool for
prototyping a few qubit quantum device. It allows the complete reconstruction
of the state produced from a given input into the device. From this
reconstructed density matrix, relevant quantum information quantities such as
the degree of entanglement and entropy can be calculated. Generally orthogonal
measurements have been discussed for this tomographic reconstruction. In this
paper, we extend the tomographic reconstruction technique to two new regimes.
First we show how non-orthogonal measurement allow the reconstruction of the
state of the system provided the measurements span the Hilbert space. We then
detail how quantum state tomography can be performed for multi qudits with a
specific example illustrating how to achieve this in one and two qutrit
systems.Comment: 6 pages, 4 figures, submitted to PR
Neural correlates of confidence during item recognition and source memory retrieval: evidence for both dual-process and strength memory theories
Abstract â– Although the medial-temporal lobes (MTL), PFC, and parietal cortex are considered primary nodes in the episodic memory network, there is much debate regarding the contributions of MTL, PFC, and parietal subregions to recollection versus familiarity (dual-process theory) and the feasibility of accounts on the basis of a single memory strength process (strength theory). To investigate these issues, the current fMRI study measured activity during retrieval of memories that differed quantitatively in terms of strength (high vs. low-confidence trials) and qualitatively in terms of recollection versus familiarity (source vs. item memory tasks). Support for each theory varied depending on which node of the episodic memory network was considered. Results from MTL best fit a dual-process account, as a dissociation was found between a right hippocampal region showing high-confidence activity during the source memory task and bilateral rhinal regions showing highconfidence activity during the item memory task. Within PFC, several left-lateralized regions showed greater activity for source than item memory, consistent with recollective orienting, whereas a right-lateralized ventrolateral area showed low-confidence activity in both tasks, consistent with monitoring processes. Parietal findings were generally consistent with strength theory, with dorsal areas showing low-confidence activity and ventral areas showing high-confidence activity in both tasks. This dissociation fits with an attentional account of parietal functions during episodic retrieval. The results suggest that both dual-process and strength theories are partly correct, highlighting the need for an integrated model that links to more general cognitive theories to account for observed neural activity during episodic memory retrieval.
Strain-induced kinetics of intergrain defects as the mechanism of slow dynamics in the nonlinear resonant response of humid sandstone bars
A closed-form description is proposed to explain nonlinear and slow dynamics
effects exhibited by sandstone bars in longitudinal resonance experiments.
Along with the fast subsystem of longitudinal nonlinear displacements we
examine the strain-dependent slow subsystem of broken intergrain and
interlamina cohesive bonds. We show that even the simplest but
phenomenologically correct modelling of their mutual feedback elucidates the
main experimental findings typical for forced longitudinal oscillations of
sandstone bars, namely, (i) hysteretic behavior of a resonance curve on both
its up- and down-slopes, (ii) linear softening of resonant frequency with
increase of driving level, and (iii) gradual recovery (increase) of resonant
frequency at low dynamical strains after the sample was conditioned by high
strains. In order to reproduce the highly nonlinear elastic features of
sandstone grained structure a realistic non-perturbative form of strain
potential energy was adopted. In our theory slow dynamics associated with the
experimentally observed memory of peak strain history is attributed to
strain-induced kinetic changes in concentration of ruptured inter-grain and
inter-lamina cohesive bonds causing a net hysteretic effect on the elastic
Young's modulus. Finally, we explain how enhancement of hysteretic phenomena
originates from an increase in equilibrium concentration of ruptured cohesive
bonds that are due to water saturation.Comment: 5 pages, 3 figure
Fermion Masses in Emergent Electroweak Symmetry Breaking
We consider the generation of fermion masses in an emergent model of
electroweak symmetry breaking with composite gauge bosons. A universal
bulk fermion profile in a warped extra dimension is used for all fermion
flavors. Electroweak symmetry is broken at the UV (or Planck) scale where
boundary mass terms are added to generate the fermion flavor structure. This
leads to flavor-dependent nonuniversality in the gauge couplings. The effects
are suppressed for the light fermion generations but are enhanced for the top
quark where the and couplings can deviate at the
level in the minimal setup. By the AdS/CFT correspondence our model
implies that electroweak symmetry is not a fundamental gauge symmetry. Instead
the Standard Model with massive fermions and gauge bosons is an effective
chiral Lagrangian for some underlying confining strong dynamics at the TeV
scale, where mass is generated without a Higgs mechanism.Comment: modified discussion in Sec 3.1, version published in JHE
Recent advances in understanding resistance exercise training-induced skeletal muscle hypertrophy in humans
Skeletal muscle plays a pivotal role in the maintenance of physical and metabolic health and, critically, mobility. Accordingly, strategies focused on increasing the quality and quantity of skeletal muscle are relevant, and resistance exercise is foundational to the process of functional hypertrophy. Much of our current understanding of skeletal muscle hypertrophy can be attributed to the development and utilization of stable isotopically labeled tracers. We know that resistance exercise and sufficient protein intake act synergistically and provide the most effective stimuli to enhance skeletal muscle mass; however, the molecular intricacies that underpin the tremendous response variability to resistance exercise-induced hypertrophy are complex. The purpose of this review is to discuss recent studies with the aim of shedding light on key regulatory mechanisms that dictate hypertrophic gains in skeletal muscle mass. We also aim to provide a brief up-to-date summary of the recent advances in our understanding of skeletal muscle hypertrophy in response to resistance training in humans
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