348 research outputs found
Laser in situ Keratomileusis Sonrası Pterjiyum
Pterjiyumun ilerlemesini önlemek amacıyla ultraviyole filtreli güneş gözlüğü
ve şapka kullanımı önerilmekte ancak ilerlemeyi kesin önleyici tıbbi veya
cerrahi bir teknik bulunmamaktadır. Sunduğumuz olguda; laser in situ keratomileusis
(LASIK) tedavisinden 7 yıl sonra gelişen pterjiyuma karşı flep
kenarının bir bariyer görevi gördüğü ve pterjiyumun takip edildiği 2,5 yıl
boyunca ilerlemediği izlenmiştir. Literatürde, LASIK sonrası gelişen pterjiyumların
seyrine dair veri mevcut değildir. Olgumuz, hem LASIK sonrası bu
seyri dökümante etmek, hem de erken evrede korneaya yapılacak bir kesinin
pterjiyumu durdurucu etkisini sorgulamak açısından önem taşımaktadır
Parametric level statistics in random matrix theory: Exact solution
An exact solution to the problem of parametric level statistics in
non-Gaussian ensembles of N by N Hermitian random matrices with either soft or
strong level confinement is formulated within the framework of the orthogonal
polynomial technique. Being applied to random matrices with strong level
confinement, the solution obtained leads to emergence of a new connection
relation that makes a link between the parametric level statistics and the
scalar two-point kernel in the thermodynamic limit.Comment: 4 pages (revtex
Microscopic universality with dynamical fermions
It has recently been demonstrated in quenched lattice simulations that the
distribution of the low-lying eigenvalues of the QCD Dirac operator is
universal and described by random-matrix theory. We present first evidence that
this universality continues to hold in the presence of dynamical quarks. Data
from a lattice simulation with gauge group SU(2) and dynamical staggered
fermions are compared to the predictions of the chiral symplectic ensemble of
random-matrix theory with massive dynamical quarks. Good agreement is found in
this exploratory study. We also discuss implications of our results.Comment: 5 pages, 3 figures, minor modifications, to appear in Phys. Rev. D
(Rapid Commun.
Spectra of massive and massless QCD Dirac operators: A novel link
We show that integrable structure of chiral random matrix models incorporating global symmetries of QCD Dirac operators (labeled by the Dyson index beta=1,2, and 4) leads to emergence of a connection relation between the spectral statistics of massive and massless Dirac operators. This novel link established for beta-fold degenerate massive fermions is used to explicitly derive (and prove the random matrix universality of) statistics of low--lying eigenvalues of QCD Dirac operators in the presence of SU(2) massive fermions in the fundamental representation (beta=1) and SU(N_c >= 2) massive adjoint fermions (beta=4). Comparison with available lattice data for SU(2) dynamical staggered fermions reveals a good agreement
Vaccination coverage and reasons for non-vaccination in a district of Istanbul
BACKGROUND: In order to control and eliminate the vaccine preventable diseases it is important to know the vaccination coverage and reasons for non-vaccination. The primary objective of this study was to determine the complete vaccination rate; the reasons for non-vaccination and the predictors that influence vaccination of children. The other objective was to determine coverage of measles vaccination of the Measles Immunization Days (MID) 2005 for children aged 9 month to 6 years in a region of Umraniye, Istanbul, Turkey. METHODS: A '30 × 7' cluster sampling design was used as the sampling method. Thirty streets were selected at random from study area. Survey data were collected by a questionnaire which was applied face to face to parents of 221 children. A Chi-square test and logistic regression was used for the statistical analyses. Content analysis method was used to evaluate the open-ended questions. RESULTS: The complete vaccination rate for study population was 84.5% and 3.2% of all children were totally non-vaccinated. The siblings of non-vaccinated children were also non-vaccinated. Reasons for non-vaccination were as follows: being in the village and couldn't reach to health care services; having no knowledge about vaccination; the father of child didn't allow vaccination; intercurrent illness of child during vaccination time; missed opportunities like not to shave off a vial for only one child. In logistic regression analysis, paternal and maternal levels of education and immigration time of both parents to Istanbul were found to influence whether children were completely vaccinated or non-vaccinated. Measles vaccination coverage during MID was 79.3%. CONCLUSION: Efforts to increase vaccination coverage should take reasons for non-vaccination into account
Distribution of the k-th smallest Dirac operator eigenvalue
Based on the exact relationship to Random Matrix Theory, we derive the
probability distribution of the k-th smallest Dirac operator eigenvalue in the
microscopic finite-volume scaling regime of QCD and related gauge theories.Comment: REVTeX 3.1, 6 pages, 1 figure. Corrected factors in eqs. (16a) and
(16c) and very minor typos (v2
A synthetic biological quantum optical system
In strong plasmon–exciton coupling, a surface plasmon mode is coupled to an array of localized emitters to yield new hybrid light–matter states (plexcitons), whose properties may in principle be controlled via modification of the arrangement of emitters. We show that plasmon modes are strongly coupled to synthetic light-harvesting maquette proteins, and that the coupling can be controlled via alteration of the protein structure. For maquettes with a single chlorin binding site, the exciton energy (2.06 ± 0.07 eV) is close to the expected energy of the Qy transition. However, for maquettes containing two chlorin binding sites that are collinear in the field direction, an exciton energy of 2.20 ± 0.01 eV is obtained, intermediate between the energies of the Qx and Qy transitions of the chlorin. This observation is attributed to strong coupling of the LSPR to an H-dimer state not observed under weak coupling
Universality in Chiral Random Matrix Theory at and
In this paper the kernel for the spectral correlation functions of the
invariant chiral random matrix ensembles with real () and quaternion
real () matrix elements is expressed in terms of the kernel of the
corresponding complex Hermitean random matrix ensembles (). Such
identities are exact in case of a Gaussian probability distribution and, under
certain smoothness assumptions, they are shown to be valid asymptotically for
an arbitrary finite polynomial potential. They are proved by means of a
construction proposed by Br\'ezin and Neuberger. Universal behavior at the hard
edge of the spectrum for all three chiral ensembles then follows from
microscopic universality for as shown by Akemann, Damgaard, Magnea
and Nishigaki.Comment: 4 pages, modified discussion of edge contributions and corrected
typo
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