798 research outputs found
Density fluctuations and a first-order chiral phase transition in non-equilibrium
The thermodynamics of a first-order chiral phase transition is considered in
the presence of spinodal phase separation using the Nambu-Jona-Lasinio model in
the mean field approximation. We focus on the behavior of conserved charge
fluctuations. We show that in non-equilibrium the specific heat and charge
susceptibilities diverge as the system crosses the isothermal spinodal lines.Comment: 4 pages, 1 figure, to appear in the proceedings of Chiral07, November
13-16 2007, Osaka, Japa
Probing the QCD Critical Point with Higher Moments of Net-proton Multiplicity Distributions
Higher moments of event-by-event net-proton multiplicity distributions are
applied to search for the QCD critical point in the heavy ion collisions. It
has been demonstrated that higher moments as well as moment products are
sensitive to the correlation length and directly connected to the thermodynamic
susceptibilities computed in the Lattice QCD and Hadron Resonance Gas (HRG)
model. In this paper, we will present measurements for kurtosis (),
skewness () and variance () of net-proton multiplicity
distributions at the mid-rapidity () and GeV/ for
Au+Au collisions at =19.6, 39, 62.4, 130 and 200 GeV, Cu+Cu
collisions at =22.4, 62.4 and 200 GeV, d+Au collisions at
=200 GeV and p+p collisions at =62.4 and 200 GeV.
The moment products and of net-proton
distributions, which are related to volume independent baryon number
susceptibility ratio, are compared to the Lattice QCD and HRG model
calculations. The and of net-proton
distributions are consistent with Lattice QCD and HRG model calculations at
high energy, which support the thermalization of the colliding system.
Deviations of and for the Au+Au collisions at
low energies from HRG model calculations are also observed.Comment: 10 pages, 8 figures, Proceedings of 27th Winter Workshon on Nuclear
Dynamics. Feb. 6-13 (2011
The Spectral Function in a Relativistic Resonance Model
We calculate the spectral function of the meson in nuclear
matter. The calculation is performed in the {\it low density} approximation,
where the in-medium self energy is completely determined by the
vacuum forward scattering amplitude. This amplitude is derived from a
relativistic resonance model. In comparison to previous non-relativistic
calculations we find a much weaker momentum dependence of ,
especially in the transverse channel. Special attention is paid to
uncertainties in the model. Thus, we compare the impact of different coupling
schemes for the interaction on the results and discuss various
resonance parameter sets.Comment: 47 pages, 19 figures, some discussion and formulae added, minor typos
removed, accepted for publication in Nuclear Physics
Constraints on vector mesons with finite momentum in nuclear matter
Using the QCD operator product expansion, we derive the real part of the transverse and longitudinal vector-vector correlation function with the quantum numbers of the rho and omega mesons to leading order in density and three momentum (q^2) for energy . The operator product expansion provides, through the Borel transformed energy dispersion relation, a model independent constraint for the momentum dependence of the vector meson spectral density in nuclear matter. Existing model calculations for the dispersion effect of the rho meson, where the vector-meson nucleon scattering amplitude is obtained by resonance saturation in the s-channel, in general violate this constraint. We trace this to an inconsistent choice for the form factor of the vertex. With a consistent choice, where both the form factor and the coupling constant are obtained from the Bonn potential, the contribution of the is substantially reduced and we find good agreement with the constraint equation. We briefly comment on the implications of our result for attempts to interpret the enhancement of low-mass dileptons in heavy-ion collisions
Quark Number Fluctuations in a Chiral Model at Finite Baryon Chemical Potential
We discuss the net quark and isovector fluctuations as well as off-diagonal
quark flavor susceptibilities along the chiral phase transition line in the
Nambu--Jona-Lasinio (NJL) model. The model is formulated at non-zero quark and
isospin chemical potentials with non-vanishing vector couplings in the
iso-scalar and iso-vector channels. We study the influence of the quark
chemical potential on the quark flavour susceptibilities in detail and the
dependence of the results on model parameters as well as on the quark mass. The
NJL model findings are compared with recent lattice results obtained in
two--flavor QCD at finite chemical potential. On a qualitative level, the NJL
model provides a consistent description of the dependence of quark number
fluctuations on temperature and baryon chemical potential. The phase diagram
and the position of the tricritical point in the NJL model are also discussed
for different parameter sets.Comment: 33 pages, 11 figures; final version accepted for publication in Phys.
Rev.
Ekolalia kommunikointikeinona autismikirjossa ja siihen kohdistetun tutkimuksen tarkastelu
Tiivistelmä. Autismikirjon häiriö on neurokehityksellinen häiriö, jolle on tunnusomaista haasteet kommunikaatiossa ja sosiaalisessa vuorovaikutuksessa sekä toistuvat, rajoittuneet ja poikkeavat toiminnot ja kiinnostuksenkohteet. Ekolalia eli toisen ihmisen puheen toistaminen on äännetty stereotypia ja yksi autismikirjoon kuuluvista kommunikaation ja puheen piirteistä. Ekolalia voidaan luokitella eri muotoihin sen perusteella, milloin puheen toistaminen tapahtuu ja kuinka paljon puheen sisältöä muokataan. Se on usein mielletty automaattiseksi toiminnoksi ilman kommunikatiivisia tavoitteita, mutta käsitys siitä on murroksessa. Tämän kandidaatintutkielman tavoitteena oli tutkia, mikä funktio ekolalialla on autismikirjon henkilöiden kommunikaatiossa ja selvittää, miten suhtautuminen ekolaliaan kommunikointimenetelmänä on muuttunut.
Tutkielma suoritettiin kirjallisuuskatsauksena, jossa käsiteltiin kahdeksan vuosina 1983–2021 välillä julkaistujen artikkelien kautta ekolaliaa. Kuutta artikkelia käytettiin vastaamaan ensimmäiseen tutkimuskysymykseen ja kaikkia kahdeksaa artikkelia toiseen tutkimuskysymykseen. Tutkimuksen päätulokseksi muodostui ekolalian moninaisuus. Autismikirjon henkilöt käyttivät ekolaliaa oman toiminnan itsesäätelyyn mutta myös kommunikointiin toisten ihmisten kanssa. Ekolaliaa ilmeni etenkin silloin, kun henkilön kielelliset taidot eivät olleet tilanteeseen adekvaatit tai henkilön kognitiivinen taso on keskivertoa matalampi. Kuitenkin ekolalian lievennetty muoto on usein indikaattori siitä, että henkilön kielelliset taidot ovat kehittymässä.
Ekolaliaan suhtautuminen on ollut vaihtelevaa vuosikymmenten varrella, eikä kehitys suhtautumisen suhteen ole ollut kronologista. Ekolalia on nähty joko potentiaalisena menetelmänä kommunikointiin tai oppimista ja kielellistä kehittymistä haittaavana. Käsitys ekolaliasta on kuitenkin nyt muuttumassa ja yhä useampi tutkimus keskittyy mahdollisuuksiin ottaa ekolalia huomioono vuorovaikutuksessa paremmin kuin ennen.
Tutkielma tukee näkemystä, että ekolalia on monipuolista, useilla eri tavoilla kommunikatiivista ja ei-kommunikatiivista. Jokapäiväisen onnistuneen vuorovaikutuksen taustalla toimii autismikirjon henkilön lähiympäristön tarjoama informaatio henkilön käyttämän ekolalian perimmäisestä merkityksestä
Вивчення стану ґрунтових вод в умовах міста
The technique of systemization and analysis of heterogenious data by form and contents pursuant to the formation of geoinformational database of underground levels has been developed. Uses of means of the spatial analysis and opportunities of integration Geoinformation technologies with the problemoriented modeling systems essentially expand an opportunity of research and an estimation of change of a level of subsoil waters in territories of city agglomerations
Re-placing place in marketing: A resource-exchange place perspective
This study clarifies the marketing discipline's conceptualization of place by presenting a revised perspective and conceptual framework of place, referred to as REPLACE. Drawing from resource exchange theory and attention restoration theory, the framework problematizes the assumption that places are merely physical locales by foregrounding how places can become inseparable aspects of consumers' lives. We present an alternative resource-based perspective of place, namely as a repository of resources that are potentially available to consumers through exchange processes. These exchange processes, and the complexity of the offered resources, influence consumers' relationship with a locale as well as their sense of well-being. With this alternative perspective, we bridge the place concept to public health and extend the understanding of attachment in service settings
Extraction of Airways with Probabilistic State-space Models and Bayesian Smoothing
Segmenting tree structures is common in several image processing
applications. In medical image analysis, reliable segmentations of airways,
vessels, neurons and other tree structures can enable important clinical
applications. We present a framework for tracking tree structures comprising of
elongated branches using probabilistic state-space models and Bayesian
smoothing. Unlike most existing methods that proceed with sequential tracking
of branches, we present an exploratory method, that is less sensitive to local
anomalies in the data due to acquisition noise and/or interfering structures.
The evolution of individual branches is modelled using a process model and the
observed data is incorporated into the update step of the Bayesian smoother
using a measurement model that is based on a multi-scale blob detector.
Bayesian smoothing is performed using the RTS (Rauch-Tung-Striebel) smoother,
which provides Gaussian density estimates of branch states at each tracking
step. We select likely branch seed points automatically based on the response
of the blob detection and track from all such seed points using the RTS
smoother. We use covariance of the marginal posterior density estimated for
each branch to discriminate false positive and true positive branches. The
method is evaluated on 3D chest CT scans to track airways. We show that the
presented method results in additional branches compared to a baseline method
based on region growing on probability images.Comment: 10 pages. Pre-print of the paper accepted at Workshop on Graphs in
Biomedical Image Analysis. MICCAI 2017. Quebec Cit
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