Structure–Function Mapping: Variability and Conviction in Tracing Retinal Nerve Fiber Bundles and Comparison to a Computational Model

yesPurpose: We evaluated variability and conviction in tracing paths of retinal nerve fiber bundles (RNFBs) in retinal images, and compared traced paths to a computational model that produces anatomically-customized structure–function maps. Methods: Ten retinal images were overlaid with 24-2 visual field locations. Eight clinicians and 6 naïve observers traced RNFBs from each location to the optic nerve head (ONH), recording their best estimate and certain range of insertion. Three clinicians and 2 naïve observers traced RNFBs in 3 images, 3 times, 7 to 19 days apart. The model predicted 10° ONH sectors relating to each location. Variability and repeatability in best estimates, certain range width, and differences between best estimates and model-predictions were evaluated. Results: Median between-observer variability in best estimates was 27° (interquartile range [IQR] 20°–38°) for clinicians and 33° (IQR 22°–50°) for naïve observers. Median certain range width was 30° (IQR 14°–45°) for clinicians and 75° (IQR 45°–180°) for naïve observers. Median repeatability was 10° (IQR 5°–20°) for clinicians and 15° (IQR 10°–29°) for naïve observers. All measures were worse further from the ONH. Systematic differences between model predictions and best estimates were negligible; median absolute differences were 17° (IQR 9°–30°) for clinicians and 20° (IQR 10°–36°) for naïve observers. Larger departures from the model coincided with greater variability in tracing. Conclusions: Concordance between the model and RNFB tracing was good, and greatest where tracing variability was lowest. When RNFB tracing is used for structure–function mapping, variability should be considered

The importance of self-consistency in determining interface properties of S-I-N and D-I-N structures

We develop a method to solve the Bogoliubov de Gennes equation for superconductors self-consistently, using the recursion method. The method allows the pairing interaction to be either local or non-local corresponding to $s$ and $d$--wave superconductivity, respectively. Using this method we examine the properties of various $S-I-N$ and $D-I-N$ interfaces. In particular we self-consistently calculate the spatially varying density of states and the superconducting order parameter. We see that changing the strength of the insulating barrier, at the interface, does not, in the case of an $s$--wave superconductor, dramatically, change the low energy local density of states, in the superconducting region near the interface. This is in stark contrast to what we see in the case of a $D-I-N$ interface where the local particle density of states is changed dramatically. Hence we deduce that in calculating such properties as the conductance of $S-I-N$ and $D-I-N$ structures it is far more important to carry out a self-consistent calculations in the $d$--wave case.Comment: 14 pages, 8 figures, submitted to special issue of "Superlattices and Microstructures

Linking the beneficial effects of current therapeutic approaches in diabetes to the vascular endothelin system

The rising epidemic of diabetes worldwide is of significant concern. Although the ultimate objective is to prevent the development and find a cure for the disease, prevention and treatment of diabetic complications is very important. Vascular complications in diabetes, or diabetic vasculopathy, include macro- and microvascular dysfunction and represent the principal cause of morbidity and mortality in diabetic patients. Endothelial dysfunction plays a pivotal role in the development and progression of diabetic vasculopathy. Endothelin-1 (ET-1), an endothelial cell-derived peptide, is a potent vasoconstrictor with mitogenic, pro-oxidative and pro-inflammatory properties that are particularly relevant to the pathophysiology of diabetic vasculopathy. Overproduction of ET-1 is reported in patients and animal models of diabetes and the functional effects of ET-1 and its receptors are also greatly altered in diabetic conditions. The current therapeutic approaches in diabetes include glucose lowering, sensitization to insulin, reduction of fatty acids and vasculoprotective therapies. However, whether and how these therapeutic approaches affect the ET-1 system remain poorly understood. Accordingly, in the present review, we will focus on experimental and clinical evidence that indicates a role for ET-1 in diabetic vasculopathy and on the effects of current therapeutic approaches in diabetes on the vascular ET-1 system

Finding a Needle in the Haystack: A Technique for Ranking Matches Between Components

Abstract. Searching and subsequently selecting reusable components from com-ponent repositories has become a key impediment for not only component-based development but also for achieving the overall usability of component develop-ment environments and the ultimate re-usability of the components themselves. Component matching, a fundamental aspect of the component search problem, has been a well-studied problem, resulting in many different matching technique

Selberg Supertrace Formula for Super Riemann Surfaces III: Bordered Super Riemann Surfaces

This paper is the third in a sequel to develop a super-analogue of the classical Selberg trace formula, the Selberg supertrace formula. It deals with bordered super Riemann surfaces. The theory of bordered super Riemann surfaces is outlined, and the corresponding Selberg supertrace formula is developed. The analytic properties of the Selberg super zeta-functions on bordered super Riemann surfaces are discussed, and super-determinants of Dirac-Laplace operators on bordered super Riemann surfaces are calculated in terms of Selberg super zeta-functions.Comment: 43 pages, amste

alpha-particle production in the scattering of 6He by 208Pb at energies around the Coulomb barrier

New experimental data from the scattering of 6He+208Pb at energies around and below the Coulomb barrier are presented. The yield of breakup products coming from projectile fragmentation is dominated by a strong group of $\alpha$ particles. The energy and angular distributions of this group have been analyzed and compared with theoretical calculations. This analysis indicates that the $\alpha$ particles emitted at backward angles in this reaction are mainly due to two-neutron transfer to weakly bound states of the final nucleus.Comment: 20 pages, 5 figures. Nuclear Physics A792 (2007) 2-1

Long range effects on the optical model of 6He around the Coulomb barrier

We present an optical model (OM) analysis of the elastic scattering data of the reactions 6He+27Al and 6He+208Pb at incident energies around the Coulomb barrier. The bare part of the optical potential is constructed microscopically by means of a double folding procedure, using the Sao Paulo prescription without any renormalization. This bare interaction is supplemented with a Coulomb dipole polarization (CDP) potential, which takes into account the effect of the dipole Coulomb interaction. For this CDP potential, we use an analytical formula derived from the semiclassical theory of Coulomb excitation. The rest of the optical potential is parametrized in terms of Woods-Saxon shapes. In the 6He+208Pb case, the analysis confirms the presence of long range components, in agreement with previous works. Four-body Continuum-Discretized Coupled-Channels calculations have been performed in order to better understand the features of the optical potentials found in the OM analysis. This study searches to elucidate some aspects of the optical potential of weakly bound systems, such as the dispersion relation and the long range (attractive and absorptive) mechanisms.Comment: Accepted in Nucl. Phys. A; 26 pages, 8 figures, 6 tables

Percolative phase separation induced by nonuniformly distributed excess oxygens

The zero-field $^{139}$La and $^{55}$Mn nuclear magnetic resonances were studied in $\rm La_{0.8}Ca_{0.2}MnO_{3+\delta}$ with different oxygen stoichiometry $\delta$. The signal intensity, peak frequency and line broadening of the $^{139}$La NMR spectrum show that excess oxygens have a tendency to concentrate and establish local ferromagnetic ordering around themselves. These connect the previously existed ferromagnetic clusters embedded in the antiferromagnetic host, resulting in percolative conduction paths. This phase separation is not a charge segregation type, but a electroneutral type. The magnetoresistance peak at the temperature where percolative paths start to form provides a direct evidence that phase separation is one source of colossal magnetoresistance effect.Comment: 4 pages, 5 figure

Shor-Preskill Type Security-Proofs for Concatenated Bennett-Brassard 1984 Quantum Key Distribution Protocol

We discuss long code problems in the Bennett-Brassard 1984 (BB84) quantum key distribution protocol and describe how they can be overcome by concatenation of the protocol. Observing that concatenated modified Lo-Chau protocol finally reduces to the concatenated BB84 protocol, we give the unconditional security of the concatenated BB84 protocol.Comment: 4 pages, RevTe