Edge Magnetoplasmons in Quantum Hall Line Junction Systems

A quantum Hall line junction system consists of a one-dimensional Luttinger liquid (LL) and two chiral channels that allow density waves incident upon and reflected by the LL to be measured separately. We demonstrate that interactions in a quantum Hall line junction system can be probed by studying edge magnetoplasmon absorption spectra and their polarization dependences. Strong interactions in the junction lead to collective modes that are isolated in either Luttinger liquid or contact subsystems.Comment: 4 pages, 3 figures, submitted to Phys. Rev. B Rapid Communicatio

Sex differentiation pattern in the annual fish Austrolebias charrua (Cyprinodontiformes: Rivulidae)

Sex differentiation process, determination of sexual strategy, and gametogenesis of the annual fish Austrolebias charrua are established. Evidence of histological sex differentiation in an antero-posterior gradient was observed in pre-hatching stages. Sexual strategy corresponds to the “differentiated gonochoric” pattern. Histological analyses of adult gonads showed an asynchronous spawning mode for females and continuous spawning for males. Mature oocytes presented fluid yolk. Testis organization corresponded to a restricted spermatogonial model. Herein, we report the ultrastructural organization of the vitelline envelope and the main features of the sperm of A. charrua. Taking together these results also contribute to phylogenetic studies and provide base line data to propose A. charrua as a biomonitor of contamination in a protected are

Correlations in the Sine-Gordon Model with Finite Soliton Density

We study the sine-Gordon (SG) model at finite densities of the topological charge and small SG interaction constant, related to the one-dimensional Hubbard model near half-filling. Using the modified WKB approach, we find that the spectrum of the Gaussian fluctuations around the classical solution reproduces the results of the Bethe ansatz studies. The modification of the collective coordinate method allows us to write down the action, free from infra-red divergencies. The behaviour of the density-type correlation functions is non-trivial and we demonstrate the existence of leading and sub-leading asymptotes. A consistent definition of the charge-raising operator is discussed. The superconducting-type correlations are shown to decrease slowly at small soliton densities, while the spectral weight of right (left) moving fermions is spread over neighboring "4k_F" harmonics.Comment: 12 pages, 3 eps figures, REVTEX; a discussion of fermions is adde

Scaling Exponents in the Incommensurate Phase of the Sine-Gordon and U(1) Thirring Models

In this paper we study the critical exponents of the quantum sine-Gordon and U(1) Thirring models in the incommensurate phase. This phase appears when the chemical potential $h$ exceeds a critical value and is characterized by a finite density of solitons. The low-energy sector of this phase is critical and is described by the Gaussian model (Tomonaga-Luttinger liquid) with the compactification radius dependent on the soliton density and the sine-Gordon model coupling constant $\beta$. For a fixed value of $\beta$, we find that the Luttinger parameter $K$ is equal to 1/2 at the commensurate-incommensurate transition point and approaches the asymptotic value $\beta^2/8\pi$ away from it. We describe a possible phase diagram of the model consisting of an array of weakly coupled chains. The possible phases are Fermi liquid, Spin Density Wave, Spin-Peierls and Wigner crystal.Comment: 10pages; Improved version; Submitted to Physical Review

Corneal involvement in rheumatoid arthritis: an vivo confocal study

PURPOSE. To analyze the in vivo morphology of corneal cells and nerves in patients with rheumatoid arthritis (RA), with or without secondary Sj\uf6gren\u2019s syndrome (SSII), and to investigate the correlations between corneal alterations and RA activity. METHODS. Fifty patients with RA and 30 age- and gender-matched control subjects were studied. SSII was diagnosed according to the American-European Consensus Group criteria, and RA activity was evaluated by the Lansbury index (LI). Confocal microscopy was used to investigate corneal thickness, the number of epithelial and stromal cells, and keratocyte hyperreflectivity. In addition, the sub-basal plexus was assessed for the number, tortuosity, and reflectivity of the nerve fibers and the presence of beadlike formations. RESULTS. Sixteen percent of patients with RA also had SSII. Between the SSII and non-SSII groups, no significant differences were found in the LI or in the clinical and confocal variables. Significant differences were present between patients with RA and control subjects for all the variables studied except nerve reflectivity. In patients with RA with and without SSII, LI correlated significantly with the number of beadlike formations and the number of hyperreflective, activated keratocytes. CONCLUSIONS. Confocal microscopy of patients with RA showed several changes in corneal cells and nerves. The number of beadlike formations and the number of activated keratocytes could be interpreted as confocal signs of ocular surface disease activity. These correlations with the index of systemic disease activity, LI, may provide insight regarding the pathogenic mechanisms of dry eye in patients with RA

muCool: A novel low-energy muon beam for future precision experiments

Experiments with muons ($\mu^{+}$) and muonium atoms ($\mu^{+}e^{-}$) offer several promising possibilities for testing fundamental symmetries. Examples of such experiments include search for muon electric dipole moment, measurement of muon $g-2$ and experiments with muonium from laser spectroscopy to gravity experiments. These experiments require high quality muon beams with small transverse size and high intensity at low energy. At the Paul Scherrer Institute, Switzerland, we are developing a novel device that reduces the phase space of a standard $\mu^{+}$ beam by a factor of $10^{10}$ with $10^{-3}$ efficiency. The phase space compression is achieved by stopping a standard $\mu^{+}$ beam in a cryogenic helium gas. The stopped $\mu^{+}$ are manipulated into a small spot with complex electric and magnetic fields in combination with gas density gradients. From here, the muons are extracted into the vacuum and into a field-free region. Various aspects of this compression scheme have been demonstrated. In this article the current status will be reported.Comment: 8 pages, 5 figures, TCP 2018 conference proceeding

Multiple-quasiparticle agglomerates at \nu=2/5

We investigate the dynamics of quasiparticle agglomerates in edge states of the Jain sequence for \nu=2/5. Comparison of the Fradkin-Lopez model with the Wen one is presented within a field theoretical construction, focusing on similarities and differences. We demonstrate that both models predict the same universal role for the multiple-quasiparticle agglomerates that dominate on single quasiparticles at low energy. This result is induced by the presence of neutral modes with finite velocity and is essential to explain the anomalous behavior of tunneling conductance and noise through a point contact.Comment: 6 pages, in press Physica E as proceedings of FQMT0

Peripheral Microangiopathy Changes in Pulmonary Arterial Hypertension Related to Systemic Sclerosis: Data From a Multicenter Observational Study

Systemic sclerosis (SSc) is a connective tissue disease characterized by immune-system alterations, fibrosis involving the skin and internal organs and diffuse microangiopathy. Pulmonary arterial hypertension (PAH) is a severe complication of SSc affecting about 10-15% of the patients and it is a leading cause of mortality. Due to the devastating nature of SSc-PAH, there is a clear need to systematically adopt appropriate screening programs. Nail fold videocapillaroscopy (NVC) studies have shown a more severe peripheral microvascular dysfunction in SSc patients with PAH suggesting that abnormalities in peripheral microcirculation may correlate with pulmonary microangiopathy. This is a cross-sectional study involving four tertiary University Rheumatology Units in the Center-North of Italy. Seventy patients, 35 adults with SSc and PAH confirmed by RHC (F/M 34/1; median age 65.2 ± 8.9 SD yrs), and 35 SSc patients without PAH were enrolled (F/M 3471; median age 63.3 ± 10.3 SD yrs). Clinical, laboratoristic and instrumental data were collected and NVC was performed in all patient. Specific NVC parameters were evaluated and a semi-quantitative rating scale was adopted to score these changes. Finally, patients were distributed into the suitable NVC pattern belonging to the scleroderma pattern. Our aim was to compare the peripheral microangiopathy changes in SSc patients with and without PAH, and to investigate the relationship between NVC findings and the main hemodynamic parameters of pulmonary vasculopathy. Patients with SSc-PAH+ showed a significant higher frequency of interstitial lung disease (ILD). No significant differences regarding clinical and laboratoristic parameters were observed. NVC abnormalities, avascular areas were more frequent in SSc patients with PAH, respect to those without (p = 0.03), and capillary density was significantly lower when considering grade 3 (p = 0.02). A higher NVC semiquantitative mean was found in SSc-PAH+ patients and a greater rate of the "late" pattern was detected in SSc-PAH+ subjects in respect to PAH- (57.1% vs. 25.7%) (p = 0.03). A significant correlations between pulmonary pressure values (sPAP by TTE and mPAP by RHC) and the capillary density (Spearman's rho 0.35, p = 0.04 for both). Our findings provide additional evidence to the literature data, confirming that a higher degree of peripheral nailfold microangiopathy is more common in SSc-PAH patients, and further strengthening the concept that NVC changes may run parallel with similar abnormalities inside pulmonary microcirculation

Building a stochastic template bank for detecting massive black hole binaries

Coalescence of two massive black holes is the strongest and most promising source for LISA. In fact, gravitational signal from the end of inspiral and merger will be detectable throughout the Universe. In this article we describe the first step in the two-step hierarchical search for gravitational wave signal from the inspiraling massive BH binaries. It is based on the routinely used in the ground base gravitational wave astronomy method of filtering the data through the bank of templates. However we use a novel Monte-Carlo based (stochastic) method to lay a grid in the parameter space, and we use the likelihood maximized analytically over some parameters, known as F-statistic, as a detection statistic. We build a coarse template bank to detect gravitational wave signals and to make preliminary parameter estimation. The best candidates will be followed up using Metropolis-Hasting stochastic search to refine the parameter estimation. We demonstrate the performance of the method by applying it to the Mock LISA data challenge 1B (training data set).Comment: revtex4, 8 figure

Is the squeezing of relic gravitational waves produced by inflation detectable?

Grishchuk has shown that the stochastic background of gravitational waves produced by an inflationary phase in the early Universe has an unusual property: it is not a stationary Gaussian random process. Due to squeezing, the phases of the different waves are correlated in a deterministic way, arising from the process of parametric amplification that created them. The resulting random process is Gaussian but non-stationary. This provides a unique signature that could in principle distinguish a background created by inflation from stationary stochastic backgrounds created by other types of processes. We address the question: could this signature be observed with a gravitational wave detector? Sadly, the answer appears to be "no": an experiment which could distinguish the non-stationary behavior would have to last approximately the age of the Universe at the time of measurement. This rules out direct detection by ground and space based gravitational wave detectors, but not indirect detections via the electromagnetic Cosmic Microwave Background Radiation (CMBR).Comment: 17 pages, 4 Postscript figures, uses revtex, psfig, to be submitted to PRD, minor revisions - appendix B clarified, corrected typos, added reference