14,261 research outputs found
Towers of recollement and bases for diagram algebras: planar diagrams and a little beyond
The recollement approach to the representation theory of sequences of
algebras is extended to pass basis information directly through the
globalisation functor. The method is hence adapted to treat sequences that are
not necessarily towers by inclusion, such as symplectic blob algebras (diagram
algebra quotients of the type-\hati{C} Hecke algebras).
By carefully reviewing the diagram algebra construction, we find a new set of
functors interrelating module categories of ordinary blob algebras (diagram
algebra quotients of the type- Hecke algebras) at {\em different} values
of the algebra parameters. We show that these functors generalise to determine
the structure of symplectic blob algebras, and hence of certain two-boundary
Temperley-Lieb algebras arising in Statistical Mechanics.
We identify the diagram basis with a cellular basis for each symplectic blob
algebra, and prove that these algebras are quasihereditary over a field for
almost all parameter choices, and generically semisimple. (That is, we give
bases for all cell and standard modules.)Comment: 61 page
Simulations of Stellar Collisions Involving Pre-Main Sequence Stars
In this paper, we present the results of smoothed particle hydrodynamic (SPH)
simulations of collisions between pre-main sequence stars and a variety of
other kinds of stars. Simulations over a range of impact parameters and
velocities were performed. We find that pre-main sequence stars tend to ``wrap
themselves'' around their impactor. We discuss the probable evolutionary state
of products of collisions between pre-main sequence stars and pre-main
sequence, main sequence, giant branch, and compact stars. The nature of the
collision product does not depend strongly on the impact parameter or the
velocity of the collision.Comment: Accepted by Ap
Measuring storage and loss moduli using optical tweezers: broadband microrheology
We present an experimental procedure to perform broadband microrheological
measurements with optical tweezers. A generalised Langevin equation is adopted
to relate the time-dependent trajectory of a particle in an imposed flow to the
frequency-dependent moduli of the complex fluid. This procedure allows us to
measure the material linear viscoelastic properties across the widest frequency
range achievable with optical tweezers.Comment: 5 pages, 3 figure
Galaxies Probing Galaxies in PRIMUS - I. Sample, Spectroscopy, and Characteristics of the z~0.5 MgII-Absorbing Circumgalactic Medium
Spectroscopy of background QSO sightlines passing close to foreground
galaxies is a potent technique for studying the circumgalactic medium (CGM).
QSOs are effectively point sources, however, limiting their potential to
constrain the size of circumgalactic gaseous structures. Here we present the
first large Keck/LRIS and VLT/FORS2 spectroscopic survey of bright (B_AB <
22.3) background galaxies whose lines of sight probe MgII 2796, 2803 absorption
from the CGM around close projected foreground galaxies at transverse distances
10 kpc < R_perp < 150 kpc. Our sample of 72 projected pairs, drawn from the
PRIsm MUlti-object Survey (PRIMUS), includes 48 background galaxies which do
not host bright AGN, and both star-forming and quiescent foreground galaxies
with stellar masses 9.0 < log M_*/M_sun < 11.2 at redshifts 0.35 < z_f/g < 0.8.
We detect MgII absorption associated with these foreground galaxies with
equivalent widths 0.25 Ang 2sigma significance in 20
individual background sightlines passing within R_perp < 50 kpc, and place
2sigma upper limits on W_2796 of <0.5 Ang in an additional 11 close sightlines.
Within R_perp < 50 kpc, W_2796 is anticorrelated with R_perp, consistent with
analyses of MgII absorption detected along background QSO sightlines.
Subsamples of these foreground hosts divided at log M_*/M_sun = 9.9 exhibit
statistically inconsistent W_2796 distributions at 30 kpc < R_perp < 50 kpc,
with the higher-M_* galaxies yielding a larger median W_2796 by 0.9 Ang.
Finally, we demonstrate that foreground galaxies with similar stellar masses
exhibit the same median W_2796 at a given R_perp to within <0.2 Ang toward both
background galaxies and toward QSO sightlines drawn from the literature.
Analysis of these datasets constraining the spatial coherence scale of
circumgalactic MgII absorption is presented in a companion paper.Comment: 36 pages, 18 figures, 5 tables. Accepted to Ap
Unification via intermediate symmetry breaking scales with the quartification gauge group
The idea of quark-lepton universality at high energies has been introduced as
a natural extension to the standard model. This is achieved by endowing leptons
with new degrees of freedom -- leptonic colour, an analogue of the familiar
quark colour. Grand and partially unified models which utilise this new gauge
symmetry SU(3)_\ell have been proposed in the context of the quartification
gauge group SU(3)^4. Phenomenologically successful gauge coupling constant
unification without supersymmetry has been demonstrated for cases where the
symmetry breaking leaves a residual SU(2)_\ell unbroken. Though attractive,
these schemes either incorporate ad hoc discrete symmetries and
non-renormalisable mass terms, or achieve only partial unification. We show
that grand unified models can be constructed where the quartification group can
be broken fully [i.e. no residual SU(2)_\ell] to the standard model gauge group
without requiring additional discrete symmetries or higher dimension operators.
These models also automatically have suppressed nonzero neutrino masses. We
perform a systematic analysis of the renormalisation-group equations for all
possible symmetry breaking routes from SU(3)^4 --> SU(3)_q x SU(2)_L x U(1)_Y.
This analysis indicates that gauge coupling unification can be achieved for
several different symmetry breaking patterns and we outline the requirements
that each gives on the unification scale. We also show that the unification
scenarios of those models which leave a residual SU(2)_\ell symmetry are not
unique. In both symmetry breaking cases, some of the scenarios require new
physics at the TeV scale, while others do not allow for new TeV phenomenology
in the fermionic sector.Comment: 25 page
Depictions of Catholic and Protestant Bodies in Elizabeth (dir. Kapur, 1998)
This article uses the film Elizabeth (dir. Kapur, 1998) as a portal for understanding the interstices between modern and early modern conceptions of religion as it is read on the body. Elizabeth examines the period of religious and political unrest immediately before and after the coronation of Queen Elizabeth I (r. 1558-1603), compressing the late 1550s through the early 1570s into a comprehensive statement on the relationship between the body, heresy, and corruption. This article investigates how lower body activities and functions, like dancing, sex, and defecation, were linked in both the film and early modern minds to immorality, corruption, and heresy. This was especially true during the sixteenth century as the English Protestant Reformation\u27s dialogic battle against Catholic clergy progressed and conspiracies against the queen mounted. By contrast, both Elizabethan contemporaries and director Shekhar Kapur establish upper body activities, like reading and intellectual work, as wholesome and virtuous. As the film follows the queen\u27s transformation from youthful sensuality to physically detached wisdom, Kapur employs ideas proposed by Elizabeth\u27s contemporaries to frame religion and corruption through bodily characterization
Calcium supplements and cancer risk : a meta-analysis of randomised controlled trials
Peer reviewedPublisher PD
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Power-Ups in Digital Games: The Rewarding Effect of Phantom Game Elementson Player Experience
Power-ups are a type of game reward that allow the player tocustomise their experience by altering gameplay for a shortperiod of time. Despite the wide use of power-ups in videogames, little is known about their effect on gaming experiences.To explore this, we conducted an experimental study that compares the experiences of players depending on their exposureto power-ups in a recreational video game. The results show that players who collected power-ups felt significantly more immersed in the game, experienced more autonomy, but didnot feel more competent or challenged than those who played the game without these collectables. Interestingly, a similareffect was observed for those players who picked up ‘placebo ’power-ups, despite the items having no effect on the gameplay. We provide a discussion of these results and their implications both for games user researchers and game designers
A cohort study of the recovery of health and wellbeing following colorectal cancer (CREW study): protocol paper
Background: the number of people surviving colorectal cancer has doubled in recent years. While much of the literature suggests that most people return to near pre-diagnosis status following surgery for colorectal cancer, this literature has largely focused on physical side effects. Longitudinal studies in colorectal cancer have either been small scale or taken a narrow focus on recovery after surgery. There is a need for a comprehensive, long-term study exploring all aspects of health and wellbeing in colorectal cancer patients. The aim of this study is to establish the natural history of health and wellbeing in people who have been treated for colorectal cancer. People have different dispositions, supports and resources, likely resulting in individual differences in restoration of health and wellbeing. The protocol described in this paper is of a study which will identify who is most at risk of problems, assess how quickly people return to a state of subjective health and wellbeing, and will measure factors which influence the course of recovery. Methods: this is a prospective, longitudinal cohort study following 1000 people with colorectal cancer over a period of two years, recruiting from 30 NHS cancer treatment centres across the UK. Questionnaires will be administered prior to surgery, and 3, 9, 15 and 24 months after surgery, with the potential to return to this cohort to explore on-going issues related to recovery after cancer. Discussion: outcomes will help inform health care providers about what helps or hinders rapid and effective recovery from cancer, and identify areas for intervention development to aid this process. Once established the cohort can be followed up for longer periods and be approached to participate in related projects as appropriate and subject to funding<br/
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