488 research outputs found
A numerical study of the formation of magnetisation plateaus in quasi one-dimensional spin-1/2 Heisenberg models
We study the magnetisation process of the one dimensional spin-1/2
antiferromagnetic Heisenberg model with modulated couplings over j=1,2,3 sites.
It turns out that the evolution of magnetisation plateaus depends on j and on
the wave number q of the modulation according to the rule of Oshikawa, et al. A
mapping of two- and three-leg zig-zag ladders on one dimensional systems with
modulated couplings yields predictions for the occurence of magnetization
plateaus. The latter are tested by numerical computations with the DMRG
algorithm.Comment: 7 pages, 10 figures, accepted for publication in Euro. Phys. J.
The rationale for preserving neighborhood open space in Newark, New Jersey\u27s north ward
A study was conducted to determine the shifts in open space availability between 1950 and 2003 in four neighborhoods in the North Ward of Newark, New Jersey. Total open space in square feet and open spaces ten thousand square feet and less were quantified to determine the extent of usable open space for the creation of community gardens or vest pocket parks.
The study identified large reductions of open space recently in the two least affluent study areas. The two more affluent study areas have also lost open space recently, but not at the magnitude of the poorer study areas. The lot sizes in the more affluent study areas tend to be larger, and access to traditional open spaces (parks) is better. In contrast, the two less affluent study areas only have vacant lots as open space, and this resource is shrinking due to new construction. Without a new framework regarding open space policy being put into effect soon, open space in the four study areas investigated for this study may be difficult to find
Core hole-electron correlation in coherently coupled molecules
We study the core hole-electron correlation in coherently coupled molecules
by energy dispersive near edge X-ray absorption fine-structure spectroscopy. In
a transient phase, which exists during the transition between two bulk
arrangements, 1,4,5,8-naphthalene-tetracarboxylicacid-dianhydride multilayer
films exhibit peculiar changes of the line shape and energy position of the
X-ray absorption signal at the C K-edge with respect to the bulk and gas phase
spectra. By a comparison to a theoretical model based on a coupling of
transition dipoles, which is established for optical absorption, we demonstrate
that the observed spectroscopic differences can be explained by an
intermolecular delocalized core hole-electron pair. By applying this model we
can furthermore quantify the coherence length of the delocalized core-exciton.Comment: 5 pages, 3 figures, Accepted Version, PRL, minor wording change
Adsorption geometry and electronic structure of iron phthalocyanine on Ag surfaces: A LEED and photoelectron momentum mapping study
We present a comprehensive study of the adsorption behavior of iron
phthalocyanine on the low-index crystal faces of silver. By combining
measurements of the reciprocal space by means of photoelectron momentum mapping
and low energy electron diffraction, the real space adsorption geometries are
reconstructed. At monolayer coverage ordered superstructures exist on all
studied surfaces containing one molecule in the unit cell in case of Ag(100)
and Ag(111), and two molecules per unit cell for Ag(110). The azimuthal tilt
angle of the molecules against the high symmetry directions of the substrate is
derived from the photoelectron momentum maps. A comparative analysis of the
momentum patterns on the substrates with different symmetry indicates that both
constituents of the twofold degenerate FePc lowest unoccupied molecular orbital
are occupied by charge transfer from the substrate at the interface
Effect of daptomycin and vancomycin on Staphylococcus epidermidis biofilms: An in vitro assessment using fluorescence in situ hybridization
Colonization of in-dwelling catheters by microbial biofilms is a major concern in patient health eventually leading to catheter-related blood stream infections. Biofilms are less susceptible to standard antibiotic therapies that are effective against planktonic bacteria. Standard procedure for the detection of microorganisms on the catheter tip is culture. However, viable but non-culturable cells (VBNCs) may be missed. The aim of this study was to evaluate the use of fluorescence in situ hybridization (FISH) as an indicator to visualize and quantify the effect of the antibiotics daptomycin and vancomycin on biofilms in situ. We established an in vitro catheter biofilm model of Staphylococcus epidermidis biofilms on polyurethane catheters. Biofilm activity was measured by FISH and correlated to colony forming units (CFU) data. Digital image analysis was used for quantification of total biofilm mass and the area of the FISH positive biofilm cells. FISH showed a pronounced effect of both antibiotics on the biofilms, with daptomycin having a significantly stronger effect in terms of both reduction of biofilm mass and number of FISH-positive cells. This supports the anti-biofilm capacity of daptomycin. Interestingly, neither antibiotic was able to eradicate all of the FISH-positive cells. In summary, FISH succeeded in visualization, quantification, and localization of antibiotic activity on biofilms. This technique adds a new tool to the arsenal of test systems for anti-biofilm compounds. FISH is a valuable complementary technique to CFU since it can be highly standardized and provides information on biofilm architecture and quantity and localization of survivor cells
Organization of the pronephric filtration apparatus in zebrafish requires Nephrin, Podocin and the FERM domain protein Mosaic eyes
AbstractPodocytes are specialized cells of the kidney that form the blood filtration barrier in the kidney glomerulus. The barrier function of podocytes depends upon the development of specialized cell–cell adhesion complexes called slit-diaphragms that form between podocyte foot processes surrounding glomerular blood vessels. Failure of the slit-diaphragm to form results in leakage of high molecular weight proteins into the blood filtrate and urine, a condition called proteinuria. In this work, we test whether the zebrafish pronephros can be used as an assay system for the development of glomerular function with the goal of identifying novel components of the slit-diaphragm. We first characterized the function of the zebrafish homolog of Nephrin, the disease gene associated with the congenital nephritic syndrome of the Finnish type, and Podocin, the gene mutated in autosomal recessive steroid-resistant nephrotic syndrome. Zebrafish nephrin and podocin were specifically expressed in pronephric podocytes and required for the development of pronephric podocyte cell structure. Ultrastructurally, disruption of nephrin or podocin expression resulted in a loss of slit-diaphragms at 72 and 96 h post-fertilization and failure to form normal podocyte foot processes. We also find that expression of the band 4.1/FERM domain gene mosaic eyes in podocytes is required for proper formation of slit-diaphragm cell–cell junctions. A functional assay of glomerular filtration barrier revealed that absence of normal nephrin, podocin or mosaic eyes expression results in loss of glomerular filtration discrimination and aberrant passage of high molecular weight substances into the glomerular filtrate
Phase diagram of an asymmetric spin ladder
We investigate an asymmetric zig-zag spin ladder with different exchange
integrals on both legs using bosonization and renormalization group. When the
leg exchange integrals and frustration both are sufficiently small,
renormalization group analysis shows that the Heisenberg critical point flows
to an intermediate-coupling fixed point with gapless excitations and a
vanishing spin velocity. When they are large, a spin gap opens and a dimer
liquid is realized. Here, we find a continuous manifold of Hamiltonians with
dimer product ground states, interpolating between the Majumdar-Ghosh and
sawtooth spin-chain model.Comment: 4 pages, 2 EPS figures, to be published in PR
Quasi-periodic spin chains in a magnetic field
We study the interplay between a (quasi) periodic coupling array and an
external magnetic field in a spin-1/2 XXZ chain. A new class of magnetization
plateaux are obtained by means of Abelian bosonization methods which give rise
to a sufficient quantization condition. The investigation of magnetic phase
diagrams via exact diagonalization of finite clusters finds a complete
agreement with the continuum treatment in a variety of situations.Comment: 4 pages RevTeX, 5 PostScript figures included. Final version to
appear in PR
Corrigendum to: Who feels affected by “out of control” sexual behavior? Prevalence and correlates of indicators for ICD-11 Compulsive Sexual Behavior Disorder in the German Health and Sexuality Survey (GeSiD)
As a result of a mistake made during the production phase, the above paper was published with the in-text citations appearing in an incorrect order, first as an Online First article on 20 September 2022, and later in the 3rd issue of Volume 11 (2022) on 26 September 2022.
DOI: 10.1556/2006.2022.0006
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