294 research outputs found
U(1) staggered Dirac operator and random matrix
We investigate the spectrum of the staggered Dirac operator in 4d quenched
U(1) lattice gauge theory and its relationship to random matrix theory. In the
confined as well as in the Coulomb phase the nearest-neighbor spacing
distribution of the unfolded eigenvalues is well described by the chiral
unitary ensemble. The same is true for the distribution of the smallest
eigenvalue and the microscopic spectral density in the confined phase. The
physical origin of the chiral condensate in this phase deserves further study.Comment: LATTICE99 (theoretical developments), 3 pages, 7 figure
Zero-modes of the QED Neuberger Dirac operator
We consider compact lattice QED in the quenched approximation. First, we
briefly summarize the spectrum of the staggered Dirac operator and its
connection with random matrix theory. Afterwards we present results for the
low-lying eigenmodes of the Neuberger overlap-Dirac operator. In the strong
coupling phase we find exact zero-modes. Subsequently we discuss possibly
related topological excitations of the U(1) lattice gauge theory.Comment: Lattice2001(confinement), 6 pages, 9 figure
An analytical and experimental investigation of three phase flow in airlift pumps used for diamondiferous marine gravel reclamation
Bibliography: leaves 75-79.This dissertation covers an investigation on airlift pumps operating in three phase flow. The investigation is specifically geared towards offshore diamond reclamation and the three phases considered are air, water and marine gravels. The purpose of the research was to develop an analytical technique to simulate mathematically an offshore airlift pump being used in the recovery of diamondiferous marine gravels. This analytical technique is incorporated into computer software which can be used to simulate prototype airlift installations in a CAD (computer aided design) environment. Extensive laboratory work has been conducted on both a 90 mm and 40 mm diameter airlift pump test facility. This investigation involved the measurement of specific components required for the theoretical simulation. Also monitored were airlift pump delivered outputs and behaviour under various operating conditions. Using this information, the proposed mathematical model was formulated, evaluated and compared with other mathematical models presented in the literature. The theoretical approach, which is based on a balance of external and internal pressures, proved successful and theoretically predicted solid and liquid output flow rates compared favourably with measured solid and liquid output flow rates. Furthermore, the computer software which was subsequently developed is presently being used in the diamond mining industry to model prototype airlift pumps. A sensitivity analysis was performed to establish the effect of all the variables used in the mathematical model
Quantum chaos and chiral symmetry at the QCD and QED phase transition
We investigate the eigenvalue spectrum of the staggered Dirac matrix in SU(3)
gauge theory and in full QCD as well as in quenched U(1) theory. As a measure
of the fluctuation properties of the eigenvalues, we consider the
nearest-neighbor spacing distribution. We find that in all regions of their
phase diagrams, compact lattice gauge theories have bulk spectral correlations
given by random matrix theory, which is an indication for quantum chaos. In the
confinement phase, the low-lying Dirac spectrum of these quantum field theories
is well described by random matrix theory, exhibiting universal behavior.
Related results for gauge theories with minimal coupling are now discussed also
in the chirally symmetric phase.Comment: 5 pages, 11 figures, talk presented at QCD 00 (Montpellier, France,
2000-07-06 -- 2000-07-13
Datenbanken der Historischen Statistik im ZHSF
The availability of historical statistical data of
high quality in machine-readable form for Germany is in a
lamentable condition. The existing data are scattered over
numerous publications. They are only partially available in
machine-readable form and only a small part of them is stored
in public archives. But not only that most of the existing
machine-readable data are not archived, for Germany we also
miss a statistical handbook for the history of economy,
society and state - in printed as well as in electronic form -
which presents the relevant figures in a systematic way. The
online data bank HISTAT tries to offer the historical statistical
data to the scientific community. This data bank
does not only present the numerous figures and time series,
it also documents the various annotations which help to understand
the figures and the sources that have been the basis
for creating the figures by the researcher, and, last but not
least, it contains the literature which was consulted when
editing the data. The final goal of this data bank is to present
the data in a systematic way. Like the Statistical Yearbook,
the online data bank must offer the categorized time
series for different regions and branches, together with all
information that are necessary to understand and evaluate
historically the meaning of these statistical data
Exact Zero-Modes of the Compact QED Dirac Operator
We calculate the low-lying eigenmodes of the Neuberger overlap-Dirac operator
for compact lattice QED in the quenched approximation. In the strong
coupling phase we find exact zero-modes, quite similar as in non-Abelian
lattice QCD. Subsequently we make an attempt to identify responsible
topological excitations of the U(1) lattice gauge theory.Comment: 10 pages, 4 figures, minor changes (typos corrected, table updated,
reference added
Lowest eigenvalues of the Dirac operator for two color QCD at nonzero chemical potential
We investigate the eigenvalue spectrum of the staggered Dirac matrix in SU(3)
and U(1) gauge theory as well as in full QCD with two colors and finite
chemical potential. Along the strong-coupling axis up to the phase transition,
the low-lying Dirac spectrum of these quantum field theories is well described
by random matrix theory and exhibits universal behavior. Related results for
gauge theories with minimal coupling are discussed in the chirally symmetric
phase and no universality is seen for the microscopic spectral densities.Comment: Lattice2001(hightemp), 3 pages, 9 figure
The Fatty Acid Synthase of the Basidiomycete Omphalotus olearius Is a Single Polypeptide
Fatty acids are essential components of almost all biological membranes. Additionally, they are important in energy storage, as second messengers during signal transduction, and in post-translational protein modification. De novo synthesis of fatty acids is essential for almost all organisms, and entails the iterative elongation of the growing fatty acid chain through a set of reactions conserved in all kingdoms. During our work on the biosynthesis of secondary metabolites, a 450-kDa protein was detected by SDS-PAGE of enriched fractions from mycelial lysates from the basidiomycete Omphalotus olearius. Protein sequencing of this protein band revealed the presence of peptides with homology to both α and β subunits of the ascomycete fatty acid synthase (FAS) family. The FAS encoding gene of O. olearius was sequenced. The positions of its predicted 21 introns were verified. The gene encodes a 3931 amino acids single protein, with an equivalent of the ascomycetous β subunit at the N-terminus and the α subunit at the C-terminus. This is the first report on an FAS protein from a homobasidiomycete and also the first fungal FAS which is comprised of a single polypeptide
Detection of Inflammatory and Homeostasis Biomarkers after Selective Removal of Carious Dentin—An In Vivo Feasibility Study
Deep carious dentin lesions induce an immune reaction within the pulp-dentin complex, leading to the release of cytokines, which might be suitable biomarkers in pulp diagnostics. This in vivo feasibility study determines the concentration of different cytokines after selective removal of carious infected dentin (SCR). In our methodology, paired samples are obtained from 21 patients—each of them with two deep carious lesions at posterior teeth without clinical symptoms. After SCR, lesions are randomly assigned to treatment strategy: Group 1 (11 patients): Carious dentin is covered either with BiodentineTM (n = 11) or gutta-percha (n = 11) before using the adhesive OptibondTM FL. Group 2 (10 patients): The adhesives ClearfilTM SE Protect Bond (n = 10) or ClearfilTM SE Bond 2 (n = 10) are directly applied. Prepared cavities are rinsed with phosphate buffered saline containing 0.05% Tween 20 (10X) for five minutes immediately after SCR (visit 1) and eight weeks later (visit 2). Rinsing liquid is regained. Concentrations of IL-1β, IL-6, IL-10, C-reactive protein (CRP), TNF-α, IFN-γ, TIMP-1, -2, and MMP-7, -8, -9 are assessed by customized multiplex assays, evaluated with fluorescence analyzer. Non-parametric statistical analysis (Wilcoxon, Mann–Whitney U Test, p < 0.05) is performed (SPSS 25). Our results show that concentrations of CRP, IL-1β, IL-6, TIMP-1, -2, and MMPs were detectable. Median concentrations of CRP, IL-1β und IL-6 were significantly higher in visit 1 (304.9, 107.4, 3.8 pg/mL), compared to visit 2 (67.8, 2.3, 0.0 pg/mL; pi < 0.001). The study revealed that the non-invasive determination of cytokines from prepared dental cavities is possible
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