10,319 research outputs found
An efficient algorithm for constructing Bayesian optimal choice designs.
Recently, Kessels et al. (2006) developed a way to produce Bayesian G- and V-optimal designs for the multinomial logitmodel. These designs allow for precise response predictions which is the goal of conjoint choice experiments. The authors showed that the G- and V- optimality criteria outperform the D- and A-optimality criteria for prediction. However, their G- and V-optimal design algorithm is computationally intensive, which is a barrier to its use in practice. In this paper, we present an efficient algorithm for calculating Bayesian optimal designs by means of the different criteria. Particularly, the speed of computation for the V-optimality criterion has improved dramatically.The new algorithm makes it possible to use Bayesian D-, A-, G- and V-optimal designs that are tailored to individual respondents in computerized conjoint choice studies.Adaptive algorithm; Bayesian D-,A-,G- and V-optimality; Cholesky decomposition; Conjoint choice design; Coordinate-exchange; Conjoint choice experiments;
Investigation into the hardbean phenomenon in phaseolus vulgaris L.
The textural deterioration of dry beans during storage was investigated. The primary symptoms of this hardbean phenomenon were found to be reduced viability, reduced water uptake and reduced cooking rate. It was found that the basic cause of the beans failing to cook - or soften - was the failure of the cotyledon cells to separate during the cooking process. From these initial observations it was hypothesised that reduced cell separation rate was due to either reduced turgor pressure due to reduced water uptake, or reduced pectin solubility, or both. Techniques used included light microscopy, transmission and scanning electron microscopy, thin-layer chromatography and spectrophotometry and it was found that reduced cell separation rate was due to a combination of both reduced water uptake and reduced pectin solubility. By inducing the hardbean symptoms artificially their relevance to textural deterioration were determined. The significant events within the beans during storage were found to be phytin breakdown, membrane deterioration, cation leakage, pectin demethylation and pectin calcification. By running a storage trial and thus allowing hardness to develop within the beans the sequence of events was elucidated
Photonic qubits, qutrits and ququads accurately prepared and delivered on demand
Reliable encoding of information in quantum systems is crucial to all
approaches to quantum information processing or communication. This applies in
particular to photons used in linear optics quantum computing (LOQC), which is
scalable provided a deterministic single-photon emission and preparation is
available. Here, we show that narrowband photons deterministically emitted from
an atom-cavity system fulfill these requirements. Within their 500 ns coherence
time, we demonstrate a subdivision into d time bins of various amplitudes and
phases, which we use for encoding arbitrary qu-d-its. The latter is done
deterministically with a fidelity >95% for qubits, verified using a newly
developed time-resolved quantum-homodyne method.Comment: 5 pages, 4 figure
Recent results of the STAR high-energy polarized proton-proton program at RHIC at BNL
The STAR experiment at the Relativistic Heavy-Ion Collider (RHIC) at
Brookhaven National Laboratory (BNL) is carrying out a spin physics program
colliding transverse or longitudinal polarized proton beams at
GeV to gain a deeper insight into the spin structure and
dynamics of the proton. These studies provide fundamental tests of Quantum
Chromodynamics (QCD).
One of the main objectives of the STAR spin physics program is the
determination of the polarized gluon distribution function through a
measurement of the longitudinal double-spin asymmetry, , for various
processes. Recent results will be shown on the measurement of for
inclusive jet production, neutral pion production and charged pion production
at GeV. In addition to these measurements involving longitudinal
polarized proton beams, the STAR collaboration has performed several important
measurements employing transverse polarized proton beams. New results on the
measurement of the transverse single-spin asymmetry, , for forward
neutral pion production and the first measurement of for mid-rapidity
di-jet production will be discussed.Comment: 8 pages, 5 figures, Invited talk given at the 17th International Spin
Physics Symposium (SPIN 2006), October 2006, Kyoto, Japa
First Results from Photon Multiplicity Detector at RHIC
We present the first measurement of multiplicity and pseudorapidity
distributions of photons in the pseudorapidity region 2.3 < eta < 3.7 for
different centralities in Au + Au collisions at sqrt{s_NN} = 62.4 GeV. The
pseudorapidity distribution of photons, dominated by neutral pion decays, has
been compared to those of identified charged pions, photons, and inclusive
charged particles from heavy ion and nucleon-nucleon collisions at various
energies. Scaling of photon yield with number of participating nucleons and
limiting fragmentation scenario for inclusive photon production has been
studied.Comment: Talk given at 5th International Conference on Physics and
Astrophysics of Quark Gluon Plasma (February 8 - 12, 2005); 4 pages and 6
figure
Properties of particle production at large transverse momentum in Au+Au and Cu+Cu collisions at RHIC
We present the incident energy and system size dependence of the pT spectra
for charged pions, protons, and anti-protons using Au+Au and Cu+Cu collisions
at Sqrt(sNN) = 62.4 and 200 GeV in STAR experiment at RHIC. Through these
measurements in the pT range of 0.2 < pT < 10 GeV/c we conduct a systematic
study of the beam energy, system size and particle species dependence of
nuclear modification factors and address specific predictions from the quark
coalescence models regarding the beam energy dependence of baryon enhancement
in the intermediate pT (2 < pT < 6 GeV/c) region.Comment: Talk given at 19th International Conference on Ultra-relativistic
Nucleus-Nucleus Collisions: Quark Matter 2006 (QM 2006), Shanghai, China,
14-20 Nov. 200
Responding to Environmental Injustice: The Civil Rights Act and American Federal Institutional and Systemic Barriers to Private Redress of Disparate Environmental Harm
This article discusses the use of private action in federal institutions for relief from disparate racial impacts. The courts have eliminated consideration of § 602 disparate impact regulations as the basis for a private right of action challenging environmental harms. Legislative action seems unlikely in this era of gridlock and partisan polarization. Agency action seems to offer the most avenues for consideration of environmental justice concerns. However, agencies are bureaucratic and subject to election results, Congressional oversight and budgetary limitations, and backlogs of determination of environmental justice complaints. Deeply rooted systemic institutional racism further constrains possible reforms to the federal branches of government
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