75 research outputs found
The Master Equation for Large Population Equilibriums
We use a simple N-player stochastic game with idiosyncratic and common noises
to introduce the concept of Master Equation originally proposed by Lions in his
lectures at the Coll\`ege de France. Controlling the limit N tends to the
infinity of the explicit solution of the N-player game, we highlight the
stochastic nature of the limit distributions of the states of the players due
to the fact that the random environment does not average out in the limit, and
we recast the Mean Field Game (MFG) paradigm in a set of coupled Stochastic
Partial Differential Equations (SPDEs). The first one is a forward stochastic
Kolmogorov equation giving the evolution of the conditional distributions of
the states of the players given the common noise. The second is a form of
stochastic Hamilton Jacobi Bellman (HJB) equation providing the solution of the
optimization problem when the flow of conditional distributions is given. Being
highly coupled, the system reads as an infinite dimensional Forward Backward
Stochastic Differential Equation (FBSDE). Uniqueness of a solution and its
Markov property lead to the representation of the solution of the backward
equation (i.e. the value function of the stochastic HJB equation) as a
deterministic function of the solution of the forward Kolmogorov equation,
function which is usually called the decoupling field of the FBSDE. The
(infinite dimensional) PDE satisfied by this decoupling field is identified
with the \textit{master equation}. We also show that this equation can be
derived for other large populations equilibriums like those given by the
optimal control of McKean-Vlasov stochastic differential equations. The paper
is written more in the style of a review than a technical paper, and we spend
more time and energy motivating and explaining the probabilistic interpretation
of the Master Equation, than identifying the most general set of assumptions
under which our claims are true
Evaluation of the Safety and Immunogenicity of the RTS,S/AS01E Malaria Candidate Vaccine When Integrated in the Expanded Program of Immunization
Background. The RTS,S/AS01E malaria candidate vaccine is being developed for immunization of African infants through the Expanded Program of Immunization (EPI). Methods. This phase 2, randomized, open, controlled trial conducted in Ghana, Tanzania, and Gabon evaluated the safety and immunogenicity of RTS,S/AS01E when coadministered with EPI vaccines. Five hundred eleven infants were randomized to receive RTS,S/AS01E at 0, 1, and 2 months (in 3 doses with diphtheria, tetanus, and wholecell pertussis conjugate [DTPw]; hepatitis B [HepB]; Haemophilus influenzae type b [Hib]; and oral polio vaccine [OPV]), RTS,S/AS01E at 0, 1, and 7 months (2 doses with DTPwHepB/Hib+OPV and 1 dose with measles and yellow fever), or EPI vaccines only. Results. The occurrences of serious adverse events were balanced across groups; none were vaccine-related. One child from the control group died. Mild to moderate fever and diaper dermatitis occurred more frequently in the RTS,S/AS01E coadministration groups. RTS,S/AS01E generated high anti-circumsporozoite protein and anti- hepatitis B surface antigen antibody levels. Regarding EPI vaccine responses upon coadministration when considering both immunization schedules, despite a tendency toward lower geometric mean titers to some EPI antigens, predefined noninferiority criteria were met for all EPI antigens except for polio 3 when EPI vaccines were given with RTS,S/AS01E at 0, 1, and 2 months. However, when antibody levels at screening were taken into account, the rates of response to polio 3 antigens were comparable between groups. Conclusion. RTS,S/AS01E integrated in the EPI showed a favorable safety and immunogenicity evaluation. Trial registration. ClinicalTrials.gov identifier: NCT00436007. GlaxoSmithKline study ID number: 106369 (Malaria-050
Investigating the NCQ scaling of elliptic flow at LHC with a multiphase transport model
The number of constituent quark (NCQ) scaling behavior of elliptic flow has
been systematically studied at the LHC energy within the framework of a
multiphase transport model (AMPT) in this work. We find that the parameters
used to generate the initial states and the collision centrality are important
for the existence of NCQ scaling even when hadronic rescattering contribution
is off in Pb-Pb collisions of TeV. By turning on the
hadron rescattering process, the hadronic evolution impacts are also found to
be significant. Extending the analysis to Pb-Pb collsions of
TeV, one would observe similar qualitative features
Coalescence Models For Hadron Formation From Quark Gluon Plasma
We review hadron formation from a deconfined quark gluon plasma (QGP) via
coalescence or recombination of quarks and gluons. We discuss the abundant
experimental evidence for coalescence from the Relativistic Heavy Ion Collider
(RHIC) and compare the various coalescence models advocated in the literature.
We comment on the underlying assumptions and remaining challenges as well as
the merits of the models. We conclude with a discussion of some recent
developments in the field.Comment: Review to appear in Annu. Rev. Nucl. Part. Sci. 58; 58 pages, 13
figures, 1 tabl
The QCD confinement transition: hadron formation
We review the foundations and the applications of the statistical and the
quark recombination model as hadronization models.Comment: 45 pages, 16 figures, accepted for publication in Landolt-Boernstein
Volume 1-23
Nucleon strangeness polarization from hyperon production in polarized proton-proton collision at RHIC
We calculate the inclusive production of a polarized or
hyperon from the single longitudinally polarized proton and
proton () collision at RHIC. By comparing the data reported by the STAR
Collaboration, we find that this process is sensitive to the polarization of
strange and antistrange quarks of the proton in the experimental range. By
introducing asymmetric coefficients with the minimization of , we
further identify the asymmetry of the polarized strange-antistrange quarks in
the proton sea and find that the first moment is for strange quark and for
antistrange quark, with central values agreeing with the light-cone
meson-baryon fluctuation model prediction, the recent lattice QCD determination
of strangeness polarization and results from a global QCD analysis given by the
Jefferson Lab Angular Momentum (JAM) Collaboration.Comment: 10 latex pages, 6 figures, final version for publicatio
Circumnuclear regions of different BPT types in star-forming MaNGA galaxies: AGN detectability
We consider the circumnuclear regions of MaNGA galaxies. The spectra are
classified as AGN-like, HII-region-like (or SF-like), and intermediate (INT)
spectra according to their positions on the BPT diagram. There are the
following four configurations of the radiation distributions in the
circumnuclear regions: 1) AGN+INT, the innermost region of the AGN-like
radiation is surrounded by a ring of radiation of the intermediate type; 2)
INT, the central area of radiation of the intermediate type; 3) SF+INT, the
inner region of the HII-region-like radiation is surrounded by a ring of
radiation of the intermediate type; and 4) SF, the HII-region-like radiation
only. The LINERS of configurations 1 and 2 are examined. The spaxel spectra of
the LINERs form a sequences on the BPT diagram. The line ratios change smoothly
with radius, from AGN-like at the center to HII-region-like at larger
distances. This is in agreement with the paradigm that the LINERs are excited
by AGN activity. The AGN and INT radiation in the circumnuclear region is
accompanied by an enhanced gas velocity dispersion, s_g. The radius of the area
of the AGN and INT radiation is similar to the radius of the area with enhanced
s_g, and the central s_g,c correlates with the luminosity of the AGN+INT area.
We assume that the gas velocity dispersion can serve as an indicator of the AGN
activity. The values of s_g,c for the SF-type centers partly overlap with those
of the AGN-type centers. We find that there is a demarcation line between the
positions of the AGN-type and SF-type objects on the s_g,c - central Halpha
surface brightness diagram.Comment: 17 pages, 14 figures, accepted for publication in the A&
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