359 research outputs found
Quasi-Solitons in Dissipative Systems and Exactly Solvable Lattice Models
A system of first-order differential-difference equations with time lag
describes the formation of density waves, called as quasi-solitons for
dissipative systems in this paper. For co-moving density waves, the system
reduces to some exactly solvable lattice models. We construct a shock-wave
solution as well as one-quasi-soliton solution, and argue that there are
pseudo-conserved quantities which characterize the formation of the co-moving
waves. The simplest non-trivial one is given to discuss the presence of a
cascade phenomena in relaxation process toward the pattern formation.Comment: REVTeX, 4 pages, 1 figur
Improving signal-to-noise resolution in single molecule experiments using molecular constructs with short handles
We investigate unfolding/folding force kinetics in DNA hairpins exhibiting
two and three states with newly designed short dsDNA handles (29 bp) using
optical tweezers. We show how the higher stiffness of the molecular setup
moderately enhances the signal-to-noise ratio (SNR) in hopping experiments as
compared to conventional long handles constructs (approximately 700 bp). The
shorter construct results in a signal of higher SNR and slower
folding/unfolding kinetics, thereby facilitating the detection of otherwise
fast structural transitions. A novel analysis of the elastic properties of the
molecular setup, based on high-bandwidth measurements of force fluctuations
along the folded branch, reveals that the highest SNR that can be achieved with
short handles is potentially limited by the marked reduction of the effective
persistence length and stretch modulus of the short linker complex.Comment: Main paper: 20 pages and 6 figures. Supplementary Material: 25 page
Thermal rho and sigma mesons from chiral symmetry and unitarity
We study the temperature evolution of the rho and sigma mass and width, using
a unitary chiral approach. The one-loop pion-pion scattering amplitude in
Chiral Perturbation Theory at finite temperature is unitarized via the Inverse
Amplitude Method. Our results predict a clear increase with T of both the rho
and sigma widths. The masses decrease slightly for high T, while the
rho-pion-pion coupling increases. The rho behavior seems to be favored by
experimental results. In the sigma case, it signals chiral symmetry
restoration.Comment: 5 pages, 5 figures, revtex. References and brief comments added.
Final version to appear in Phys. Rev.
In-medium hadronic spectral functions through the soft-wall holographic model of QCD
We study the scalar glueball and vector meson spectral functions in a hot and
dense medium by means of the soft-wall holographic model of QCD. Finite
temperature and density effects are implemented through the AdS/RN metric. We
analyse the behaviour of the hadron masses and widths in the plane,
and compare our results with the experimental ones and with other theoretical
determinations.Comment: 16 pages, 6 figures. matching the published versio
Simultaneous Softening of sigma and rho Mesons associated with Chiral Restoration
Complex poles of the unitarized pi-pi scattering amplitude in nuclear matter
are studied. Partial restoration of chiral symmetry is modeled by the decrease
of in-medium pion decay constant f*_{pi}.
For large chiral restoration (f*_{pi}/f_{pi} << 1),
2nd sheet poles in the scalar (sigma) and the vector (rho) mesons are both
dictated by the Lambert W function and show universal softening as f*_{pi}
decreases.
In-medium pi-pi cross section receives substantial contribution from the soft
mode and exhibits a large enhancement in low-energy region.
Fate of this universality for small chiral restoration (f*_{pi}/f_{pi} ~ 1)
is also discussed.Comment: 5 pages, 4-eps figures, version accepted by Phys. Rev. C (R) with
minor modification
Trends in Metal Oxide Stability for Nanorods, Nanotubes, and Surfaces
The formation energies of nanostructures play an important role in
determining their properties, including the catalytic activity. For the case of
15 different rutile and 8 different perovskite metal oxides, we find that the
density functional theory (DFT) calculated formation energies of (2,2)
nanorods, (3,3) nanotubes, and the (110) and (100) surfaces may be described
semi-quantitatively by the fraction of metal--oxygen bonds broken and the
bonding band centers in the bulk metal oxide
RBP3-retinopathy - inherited high myopia and retinal dystrophy: Genetic Characterization, Natural History, and Deep Phenotyping
Objective:
To examine the genetic and clinical features and the natural history of RBP3-associated retinopathy.
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Design:
Multi-center international, retrospective, case series.
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Setting:
Three tertiary referral centers.
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Participants:
Adults and children, with molecularly confirmed RBP3-associated retinopathy.
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Main Outcomes and Measures:
Multi-center, international, retrospective, consecutive observational study in three tertiary referral centers of adults and children, with molecularly confirmed RBP3-retinopathy. The genetic, clinical and retinal imaging findings, including optical coherence tomography (OCT) and fundus autofluorescence (FAF), were investigated both cross-sectionally and longitudinally. The results of International standard full-field and pattern electroretinography (ERG; PERG) were reviewed.
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Results:
We ascertained 12 patients (5 females), from 10 families, with four patients previously reported. Eight novel disease-causing RBP3 variants were identified. Ten patients were homozygous. The mean age (±SD, range) of the group was 21.4 years (±19.1, 2.9-60.5 years) at baseline evaluation. All 12 patients were highly myopic with a mean spherical equivalent of -16.0D (range; -7.0D to -33.0D). Visual acuity was not significantly different between eyes and no significant anisometropia was observed. Mean best corrected visual acuity (BCVA) was 0.48 LogMAR (range; 0.2-1.35, SD; ± 0.29 LogMAR) at baseline. Eleven patients had longitudinal BCVA assessment, with a mean BCVA of 0.46 LogMAR after a mean follow-up of 12.6 years. All patients were symptomatic with reduced VA and myopia by the age of 7 years. All patients had myopic fundi and features in keeping with high myopia on OCT, including choroidal thinning. The 4 youngest patients had no fundus pigmentary changes, with the rest presenting with a variable degree of mid-peripheral pigmentation and macular changes. FAF showed variable phenotypes, ranging from areas of increased signal to advanced atrophy in older patients. OCT showed cystoid macular edema at presentation in three patients, which persisted during follow-up in two patients and resolved to atrophy for the third patient. The ERGs were abnormal in 9 of 9 cases, revealing variable relative involvement of rod and cone photoreceptors with additional milder dysfunction post-phototransduction in some. All but one had PERG evidence of macular dysfunction, severe in most.
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Conclusions:
This study details the clinical and functional phenotype of RBP3-retinopathy in the largest cohort reported to date. RBP3-retinopathy is a disease characterized by early onset, slow progression over decades, and high myopia. The phenotypic spectrum and natural history as described herein has prognostic and counselling implications. RBP3-related disease should be considered in children with high myopia and retinal dystrophy
Influence of flow containment and substrate entrainment upon sandy hybrid event beds containing a co-genetic mud-clast-rich division
Individual sandstone beds containing a co-genetic mud-clast-rich (MCR) division are being increasingly described from the distal reaches of many deep-water fan systems. These deposits, termed hybrid event beds, are considered to record a flow whose composition and rheology changed significantly to become increasingly more argillaceous (clay-rich), MCR and turbulence-suppressed during the deposition of a single event bed. Studies of confined systems, in which gravity flows were affected by confining sea-floor topography, have documented similar deposits recording turbulence suppression in proximity to confining sea-floor topography (e.g., basin margins). In new research from a confined, contained system from the Castagnola Basin of NW Italy, lateral transects of individual sandstone beds 5 km in extent show that individual sandstone beds contain a co-genetic MCR division which is often; 1) extensive across the basin rather than localised adjacent to confining topography; 2) exhibits rapid, significant and repeated variation in depositional character over short length scales (tens to hundreds of metres), specifically in terms of the thickness of co-genetic MCR divisions and the size and abundance of clasts contained within them; and 3) exhibits variation in depositional character over larger length scales (> 1 km) which is non-systematic in relation to palaeoflow direction or increasing proximity towards the counter slope of the downstream confining northern basin margin. A suite of factors within the Castagnola Basin is thought to have resulted in the deposition of these co-genetic MCR divisions whose thickness and distribution are less predictable in relation to confining sea-floor topography than those described from other confined uncontained settings. Specific factors include; 1) recent and voluminous entrainment of muddy substrate at seemingly random locations across the basin floor and their support and transport within a high sediment concentration gravity flow; and 2) containment (ponding) of gravity flows within a confined basin, which is thought to have established extensive and complex three dimensional flow dynamics across the basin following flow interaction with multiple basin margins. This research highlights the role of entrainment of muddy substrate and subsequent transport processes of muddy substrate for developing co-genetic MCR divisions, as well as the importance of understanding the degree of containment depositional systems experienced when considering the spatial distribution of depositional facies, and thus reservoir quality, in topographically complex settings
<i>KCNV2</i>-associated retinopathy:genotype-phenotype correlations-<i>KCNV2</i>Â study group report 3
Background/aims To investigate genotypeâphenotype associations in patients with KCNV2 retinopathy.Methods Review of clinical notes, best-corrected visual acuity (BCVA), molecular variants, electroretinography (ERG) and retinal imaging. Subjects were grouped according to the combination of KCNV2 variantsâtwo loss-of-function (TLOF), two missense (TM) or one of each (MLOF)âand parameters were compared.Results Ninety-two patients were included. The mean age of onset (mean±SD) in TLOF (n=55), TM (n=23) and MLOF (n=14) groups was 3.51±0.58, 4.07±2.76âand 5.54±3.38 years, respectively. The mean LogMAR BCVA (±SD) at baseline in TLOF, TM and MLOF groups was 0.89±0.25, 0.67±0.38 and 0.81±0.35 for right, and 0.88±0.26, 0.69±0.33âand 0.78±0.33 for left eyes, respectively. The difference in BCVA between groups at baseline was significant in right (p=0.03) and left eyes (p=0.035). Mean outer nuclear layer thickness (±SD) at baseline in TLOF, MLOF and TM groups was 37.07±15.20â”m, 40.67±12.53âand 40.38±18.67, respectively, which was not significantly different (p=0.85). The mean ellipsoid zone width (EZW) loss (±SD) was 2051â”m (±1318) for patients in the TLOF, and 1314â”m (±965) for MLOF. Only one patient in the TM group had EZW loss at presentation. There was considerable overlap in ERG findings, although the largest DA 10âERG b-waves were associated with TLOF and the smallest with TM variants.Conclusions Patients with missense alterations had better BCVA and greater structural integrity. This is important for patient prognostication and counselling, as well as stratification for future gene therapy trials
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