1,152 research outputs found
Construction and Calibration of Optically Efficient LCD-based Multi-Layer Light Field Displays
Near-term commercial multi-view displays currently employ ray-based 3D or 4D light field techniques. Conventional approaches to ray-based display typically include lens arrays or heuristic barrier patterns combined with integral interlaced views on a display screen such as an LCD panel. Recent work has placed an emphasis on the co-design of optics and image formation algorithms to achieve increased frame rates, brighter images, and wider fields-of-view using optimization-in-the-loop and novel arrangements of commodity LCD panels. In this paper we examine the construction and calibration methods of computational, multi-layer LCD light field displays. We present several experimental configurations that are simple to build and can be tuned to sufficient precision to achieve a research quality light field display. We also present an analysis of moiré interference in these displays, and guidelines for diffuser placement and display alignment to reduce the effects of moiré. We describe a technique using the moiré magnifier to fine-tune the alignment of the LCD layers
Many-body Theory vs Simulations for the pseudogap in the Hubbard model
The opening of a critical-fluctuation induced pseudogap (or precursor
pseudogap) in the one-particle spectral weight of the half-filled
two-dimensional Hubbard model is discussed. This pseudogap, appearing in our
Monte Carlo simulations, may be obtained from many-body techniques that use
Green functions and vertex corrections that are at the same level of
approximation. Self-consistent theories of the Eliashberg type (such as the
Fluctuation Exchange Approximation) use renormalized Green functions and bare
vertices in a context where there is no Migdal theorem. They do not find the
pseudogap, in quantitative and qualitative disagreement with simulations,
suggesting these methods are inadequate for this problem. Differences between
precursor pseudogaps and strong-coupling pseudogaps are also discussed.Comment: Accepted, Phys. Rev. B15 15Mar00. Expanded version of original
submission, Latex, 8 pages, epsfig, 5 eps figures (Last one new). Discussion
on fluctuation and strong coupling induced pseudogaps expande
Writing as 'Compearance' in Diário da Queda by Michel Laub
Diário da Queda (2011) by Michel Laub has been described as autoficção (autofiction), the Brazilian translation of the concept coined by Serge Doubrovsky to describe the narrative working-through of trauma through fictional autobiography. This article re-examines the definition of ‘autofiction’ and argues that Laub’s narrative process more closely resembles Jean-Luc Nancy’s notion of a singular voice ‘compearing’ experiences in a process of ‘sharing’ that, when combined with touch and affection can—according to the novel—more successfully help to overcome trauma. At stake are questions regarding the inheritance of Holocaust memory, as well as its politicised deployment in contemporary conflicts
Developing diversity through specialisation in secondary education: comparing approaches in New Zealand and England
The paper compares approaches to curriculum specialisation in secondary education in New Zealand and England. In both countries there have been movements towards increased specialisation, though these have been quite different in form and scope. In both countries specialisation cannot be divorced from broader education policies designed to increase devolution and choice and the paper discusses these contexts before analysing the different approaches to specialisation and attempting an explanation. The authors of the paper draw on findings from research undertaken in New Zealand schools. The paper identifies three dimensions that have played a part in influencing curriculum specialisation in both countries. These are opportunity, source of impetus and support. It is argued that while local initiative is possible in New Zealand, central planning and guidance is inadequate. In England while central planning is strong and support is available, it is far from clear that real specialisation is encouraged by existing curriculum and assessment frameworks. In these circumstances in both countries it seems likely that vertical, rather than horizontal, diversity will continue to hold sway
The Effects of Creatine Monohydrate Loading on Exercise Recovery in Active Women throughout the Menstrual Cycle
Creatine supplementation improves anaerobic performance and recovery; however, to date, these outcomes have not been well explored in females. This study evaluated the effect of creatine monohydrate loading on exercise recovery, measured by heart rate variability (HRV) and repeated sprint performance, in women across the menstrual cycle. In this randomized, double-blind, cross-over study, 39 women (mean ± standard deviation: age: 24.6 ± 5.9 years, height: 172.5 ± 42.3 cm, weight: 65.1 ± 8.1 kg, BF: 27.4 ± 5.8%) were randomized to a creatine monohydrate (n = 19; 20 g per day in 4 × 5 g doses) or non-caloric PL group (n = 20). HRV was measured at rest and after participants completed a repeated sprint cycling test (10 × 6 s maximal sprints). Measurements were conducted before and after supplementation in the follicular/low hormone and luteal/high hormone phases. Creatine monohydrate supplementation did not influence HRV values, as no significant differences were seen in HRV values at rest or postexercise. For repeated sprint outcomes, there was a significant phase × supplement interaction (p = 0.048) for fatigue index, with the greatest improvement seen in high hormone in the creatine monohydrate group (−5.8 ± 19.0%) compared to changes in the PL group (0.1 ± 8.1%). Sprint performance and recovery were reduced by the high hormone for both groups. Though not statistically significant, the data suggests that creatine monohydrate could help counteract performance decrements caused by the high hormone. This data can help inform creatine monohydrate loading strategies for females, demonstrating potential benefits in the high hormone phase
Where the Wild Things Are: Pathogenesis of SIV Infection in African Nonhuman Primate Hosts
African nonhuman primates that are natural hosts of simian immunodeficiency virus (SIV) are generally spared from disease progression. Pathogenic and nonpathogenic SIV infections share some major features: high viral replication, massive acute depletion of mucosal CD4+ T cells, and partial control of the virus by both adaptive and innate immune responses. A key distinction of natural SIV infections is rapid and active control of immune activation and apoptosis of T cells that contributes to the integrity of mucosal barrier and lack of microbial translocation. This allows partial recovery of CD4+ T cells and preservation of the function of other immune cell subsets. A better understanding of the mechanisms underlying the lack of disease in natural hosts for SIV infection will likely provide important clues as to the therapy of HIV-1 infection
Measurements of Dihadron Correlations Relative to the Event Plane in Au+Au Collisions at GeV
Dihadron azimuthal correlations containing a high transverse momentum (\pt)
trigger particle are sensitive to the properties of the nuclear medium created
at RHIC through the strong interactions occurring between the traversing parton
and the medium, i.e. jet-quenching. Previous measurements revealed a strong
modification to dihadron azimuthal correlations in Au+Au collisions with
respect to \pp\ and \dAu\ collisions. The modification increases with the
collision centrality, suggesting a path-length dependence to the jet-quenching
effect. This paper reports STAR measurements of dihadron azimuthal correlations
in mid-central (20-60\%) Au+Au collisions at \snn=200~GeV as a function of
the trigger particle's azimuthal angle relative to the event plane,
\phis=|\phit-\psiEP|. The azimuthal correlation is studied as a function of
both the trigger and associated particle \pt. The subtractions of the
combinatorial background and anisotropic flow, assuming Zero Yield At Minimum
(\zyam), are described. The away-side correlation is strongly modified, and the
modification varies with \phis, which is expected to be related to the
path-length that the away-side parton traverses. The pseudo-rapidity (\deta)
dependence of the near-side correlation, sensitive to long range \deta
correlations (the ridge), is also investigated. The ridge and jet-like
components of the near-side correlation are studied as a function of \phis.
The ridge appears to drop with increasing \phis while the jet-like component
remains approximately constant. ...Comment: 50 pages, 39 figures, 6 table
Observation of the antimatter helium-4 nucleus
High-energy nuclear collisions create an energy density similar to that of
the universe microseconds after the Big Bang, and in both cases, matter and
antimatter are formed with comparable abundance. However, the relatively
short-lived expansion in nuclear collisions allows antimatter to decouple
quickly from matter, and avoid annihilation. Thus, a high energy accelerator of
heavy nuclei is an efficient means of producing and studying antimatter. The
antimatter helium-4 nucleus (), also known as the anti-{\alpha}
(), consists of two antiprotons and two antineutrons (baryon
number B=-4). It has not been observed previously, although the {\alpha}
particle was identified a century ago by Rutherford and is present in cosmic
radiation at the 10% level. Antimatter nuclei with B < -1 have been observed
only as rare products of interactions at particle accelerators, where the rate
of antinucleus production in high-energy collisions decreases by about 1000
with each additional antinucleon. We present the observation of the antimatter
helium-4 nucleus, the heaviest observed antinucleus. In total 18
counts were detected at the STAR experiment at RHIC in 10 recorded Au+Au
collisions at center-of-mass energies of 200 GeV and 62 GeV per nucleon-nucleon
pair. The yield is consistent with expectations from thermodynamic and
coalescent nucleosynthesis models, which has implications beyond nuclear
physics.Comment: 19 pages, 4 figures. Submitted to Nature. Under media embarg
Studies of di-jet survival and surface emission bias in Au+Au collisions via angular correlations with respect to back-to-back leading hadrons
We report first results from an analysis based on a new multi-hadron
correlation technique, exploring jet-medium interactions and di-jet surface
emission bias at RHIC. Pairs of back-to-back high transverse momentum hadrons
are used for triggers to study associated hadron distributions. In contrast
with two- and three-particle correlations with a single trigger with similar
kinematic selections, the associated hadron distribution of both trigger sides
reveals no modification in either relative pseudo-rapidity or relative
azimuthal angle from d+Au to central Au+Au collisions. We determine associated
hadron yields and spectra as well as production rates for such correlated
back-to-back triggers to gain additional insights on medium properties.Comment: By the STAR Collaboration. 6 pages, 2 figure
An Experimental Exploration of the QCD Phase Diagram: The Search for the Critical Point and the Onset of De-confinement
The QCD phase diagram lies at the heart of what the RHIC Physics Program is
all about. While RHIC has been operating very successfully at or close to its
maximum energy for almost a decade, it has become clear that this collider can
also be operated at lower energies down to 5 GeV without extensive upgrades. An
exploration of the full region of beam energies available at the RHIC facility
is imperative. The STAR detector, due to its large uniform acceptance and
excellent particle identification capabilities, is uniquely positioned to carry
out this program in depth and detail. The first exploratory beam energy scan
(BES) run at RHIC took place in 2010 (Run 10), since several STAR upgrades,
most importantly a full barrel Time of Flight detector, are now completed which
add new capabilities important for the interesting physics at BES energies. In
this document we discuss current proposed measurements, with estimations of the
accuracy of the measurements given an assumed event count at each beam energy.Comment: 59 pages, 78 figure
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