Improving Visual Field Examination of the Macula Using Structural Information

Purpose: To investigate a novel approach for structure-function modeling in glaucoma to improve visual field testing in the macula. Methods: We acquired data from the macular region in 20 healthy eyes and 31 with central glaucomatous damage. Optical coherence tomography (OCT) scans were used to estimate the local macular ganglion cell density. Perimetry was performed with a fundus-tracking device using a 10-2 grid. OCT scans were matched to the retinal image from the fundus perimeter to accurately map the tested locations onto the structural damage. Binary responses from the subjects to all presented stimuli were used to calculate the structure-function model used to generate prior distributions for a ZEST (Zippy Estimation by Sequential Testing) Bayesian strategy. We used simulations based on structural and functional data acquired from an independent dataset of 20 glaucoma patients to compare the performance of this new strategy, structural macular ZEST (MacS-ZEST), with a standard ZEST. Results: Compared to the standard ZEST, MacS-ZEST reduced the number of presentations by 13% in reliable simulated subjects and 14% with higher rates (≥20%) of false positive or false negative errors. Reduction in mean absolute error was not present for reliable subjects but was gradually more important with unreliable responses (≥10% at 30% error rate). Conclusions: Binary responses can be modeled to incorporate detailed structural information from macular OCT into visual field testing, improving overall speed and accuracy in poor responders. Translational Relevance: Structural information can improve speed and reliability for macular testing in glaucoma practice

Back and forth from cool core to non-cool core: clues from radio-halos

X-ray astronomers often divide galaxy clusters into two classes: "cool core" (CC) and "non-cool core" (NCC) objects. The origin of this dichotomy has been the subject of debate in recent years, between "evolutionary" models (where clusters can evolve from CC to NCC, mainly through mergers) and "primordial" models (where the state of the cluster is fixed "ab initio" by early mergers or pre-heating). We found that in a well-defined sample (clusters in the GMRT Radio halo survey with available Chandra or XMM-Newton data), none of the objects hosting a giant radio halo can be classified as a cool core. This result suggests that the main mechanisms which can start a large scale synchrotron emission (most likely mergers) are the same that can destroy CC and therefore strongly supports "evolutionary" models of the CC-NCC dichotomy. Moreover combining the number of objects in the CC and NCC state with the number of objects with and without a radio-halo, we estimated that the time scale over which a NCC cluster relaxes to the CC state, should be larger than the typical life-time of radio-halos and likely shorter than about 3 Gyr. This suggests that NCC transform into CC more rapidly than predicted from the cooling time, which is about 10 Gyr in NCC systems, allowing the possibility of a cyclical evolution between the CC and NCC states.Comment: Accepted for publication in A&

Mass profiles and concentration-dark matter relation in X-ray luminous galaxy clusters

(Abriged) Assuming that the hydrostatic equilibrium holds between the intracluster medium and the gravitational potential, we constrain the NFW profiles in a sample of 44 X-ray luminous galaxy clusters observed with XMM-Newton in the redshift range 0.1-0.3. We evaluate several systematic uncertainties that affect our reconstruction of the X-ray masses. We measure the concentration c200, the dark mass M200 and the gas mass fraction within R500 in all the objects of our sample, providing the largest dataset of mass parameters for galaxy clusters in this redshift range. We confirm that a tight correlation between c200 and M200 is present and in good agreement with the predictions from numerical simulations and previous observations. When we consider a subsample of relaxed clusters that host a Low-Entropy-Core (LEC), we measure a flatter c-M relation with a total scatter that is lower by 40 per cent. From the distribution of the estimates of c200 and M200, with associated statistical (15-25%) and systematic (5-15%) errors, we use the predicted values from semi-analytic prescriptions calibrated through N-body numerical runs and measure sigma_8*Omega_m^(0.60+-0.03)= 0.45+-0.01 (at 2 sigma level, statistical only) for the subsample of the clusters where the mass reconstruction has been obtained more robustly, and sigma_8*Omega_m^(0.56+-0.04) = 0.39+-0.02 for the subsample of the 11 more relaxed LEC objects. With the further constraint from the fgas distribution in our sample, we break the degeneracy in the sigma_8-Omega_m plane and obtain the best-fit values sigma_8~1.0+-0.2 (0.75+-0.18 when the subsample of the more relaxed objects is considered) and Omega_m = 0.26+-0.01.Comment: 21 pages. A&A in press. Minor revisions to match accepted version. Corrected 2nd and 3rd column in Table 3, and equation (A.4

A new formulation of oral viscous budesonide in treating of paediatric eosinophilic oesophagitis: a pilot study

OBJECTIVES: Oral viscous budesonide is a recent therapeutic option for eosinophilic oesophagitis (EoE) compared with dietary restriction and inhaled steroids. This single-centre, open-label, not blinded study aims to evaluate the efficacy and safety of a new, preprepared oral viscous budesonide suspension (PVB) in children and adolescents with EoE. METHODS: We treated 36 children with PVB (29 boys; median age 12 years) with EoE diagnosed according to European Society for Paediatric Gastroenterology Hepatology and Nutrition guidelines. Patients <150 and >150 cm height received 2 and 4 mg PVB daily, respectively, for 12 weeks. Upper gastrointestinal endoscopy was performed at baseline, after 12 weeks of therapy and 24 weeks after the end of therapy. Baseline and post-treatment scores were calculated for symptoms, endoscopy, and histology. Serum cortisol was performed at baseline, 12, and 36 weeks. RESULTS: At the end of PVB trial, endoscopy showed macroscopic remission in 32 patients (88.9%), whereas at histology median pre- and post-treatment peak eosinophil count/high power field (HPF) markedly decreased from 42.2 (range: 15-100) to 2.9 (range: 0-30); moreover, mean symptom and histology scores impressively improved compared with baseline (P < 0.01). At 24 weeks after the end of PVB therapy, endoscopy showed oesophageal relapse in 21 patients (58.3%), whereas 15 (41.7%) were still in remission. Seven children (19.4%) with positive multichannel intraluminal impedance-pH were treated also with proton pump inhibitors. No significant difference between pre-/post-treatment morning cortisol levels occurred. CONCLUSIONS: The new PVB suspension presented in the present study is effective and safe for treating children with proven EoE. Larger placebo-controlled clinical trials would provide more information about dosing, efficacy, and long-term safety of this formulation, specifically designed for the oesophagus

The cool core state of Planck SZ-selected clusters versus X-ray selected samples: evidence for cool core bias

We characterized the population of galaxy clusters detected with the SZ effect with Planck, by measuring the cool core state of the objects in a well-defined subsample of the Planck catalogue. We used as indicator the concentration parameter Santos et al. (2008). The fraction of cool core clusters is $29 \pm 4 \%$ and does not show significant indications of evolution in the redshift range covered by our sample. We compare the distribution of the concentration parameter in the Planck sample with the one of the X-ray selected sample MACS (Mann & Ebeling, 2011): the distributions are significantly different and the cool core fraction in MACS is much higher ($59 \pm 5 \%$). Since X-ray selected samples are known to be biased towards cool cores due to the presence of their prominent surface brightness peak, we simulated the impact of the "cool core bias" following Eckert et al. (2011). We found that it plays a large role in the difference between the fractions of cool cores in the two samples. We examined other selection effects that could in principle bias SZ-surveys against cool cores but we found that their impact is not sufficient to explain the difference between Planck and MACS. The population of X-ray under-luminous objects, which are found in SZ-surveys but missing in X-ray samples (Planck Collaboration 2016), could possibly contribute to the difference, as we found most of them to be non cool cores, but this hypothesis deserves further investigation.Comment: Accepted for publication in MNRA

Spatial connectedness imposes local‐ and metapopulation‐level selection on life history through feedbacks on demography

Dispersal evolution impacts the fluxes of individuals and hence, connectivity in metapopulations. Connectivity is therefore decoupled from the structural connectedness of the patches within the spatial network. Because of demographic feedbacks, local selection also drives the evolution of other life history traits. We investigated how different levels of connectedness affect trait evolution in experimental metapopulations of the two-spotted spider mite. We separated local- and metapopulation-level selection and linked trait divergence to population dynamics. With lower connectedness, an increased starvation resistance and delayed dispersal evolved. Reproductive performance evolved locally by transgenerational plasticity or epigenetic processes. Costs of dispersal, but also changes in local densities and temporal fluctuations herein are found to be putative drivers. In addition to dispersal, demographic traits are able to evolve in response to metapopulation connectedness at both the local and metapopulation level by genetic and/or non-genetic inheritance. These trait changes impact the persistence of spatially structured populations

The two-component giant radio halo in the galaxy cluster Abell 2142

We report on a spectral study at radio frequencies of the giant radio halo in A2142 (z=0.0909), which we performed to explore its nature and origin. A2142 is not a major merger and the presence of a giant radio halo is somewhat surprising. We performed deep radio observations with the GMRT at 608 MHz, 322 MHz, and 234 MHz and with the VLA in the 1-2 GHz band. We obtained high-quality images at all frequencies in a wide range of resolutions. The radio halo is well detected at all frequencies and extends out to the most distant cold front in A2142. We studied the spectral index in two regions: the central part of the halo and a second region in the direction of the most distant south-eastern cold front, selected to follow the bright part of the halo and X-ray emission. We complemented our observations with a preliminary LOFAR image at 118 MHz and with the re-analysis of archival VLA data at 1.4 GHz. The two components of the radio halo show different observational properties. The central brightest part has higher surface brightess and a spectrum whose steepness is similar to those of the known radio halos, i.e. $\alpha^{\rm 1.78~GHz}_{\rm 118~MHz}=1.33\pm 0.08$. The ridge, which fades into the larger scale emission, is broader in size and has considerably lower surface brightess and a moderately steeper spectrum, i.e. $\alpha^{\rm 1.78~GHz}_{\rm 118~MHz}\sim 1.5$. We propose that the brightest part of the radio halo is powered by the central sloshing in A2142, similar to what has been suggested for mini-halos, or by secondary electrons generated by hadronic collisions in the ICM. On the other hand, the steeper ridge may probe particle re-acceleration by turbulence generated either by stirring the gas and magnetic fields on a larger scale or by less energetic mechanisms, such as continuous infall of galaxy groups or an off-axis merger.Comment: 18 pages, 10 figures, 4 tables - A&A, accepte

Radio emission at the centre of the galaxy cluster Abell 3560: evidence for core sloshing?

Previous radio observations of the galaxy cluster A3560 in the Shapley Concentration showed complex radio emission associated with the brightest cluster member.To understand its origin we observed it with the GMRT, the VLA and ATCA at 240 and 610 MHz, 1.28,1.4, 2.3,4.8 and 8.4 GHz, and performed a detailed morphological and spectral study of the radio emission associated with the BCG. We also observed the cluster with XMM-Newton and Chandra to derive the properties of the ICM. The radio emission of the N-E nucleus of the dumb-bell BCG shows an active radio galaxy, plus aged diffuse emission, which is not refurbished at present. Our Chandra data show that the radio active nucleus of the BCG has extended X-ray emission, which we classify as a low-luminosity corona. A residual image of the XMM-Newton brightness shows the presence of a spiral-like feature, which we interpret as the signature of gas sloshing. The presence of a subgroup is clear in the surface brightness residual map, and in the XMM-Newton temperature analysis. The optical 2D analysis shows substructure in A3560. A galaxy clump was found at the location of the X-ray subgroup, and another group is present south of the cluster core, close to the spiral-like feature. The aged part of the radio emission closely follows the spiral pattern of the X-ray residual brightness distribution, while the two active radio lobes are bent in a completely different direction. We conclude that the complex radio emission associated with the cluster BCG is the result of a minor merger event in A3560. The aged diffuse emission is strongly affected by the sloshing motion in the ICM. On the other hand, the bent jets and lobes of the current radio AGN activity may reflect a complex gas velocity field in the innermost cluster regions and/or sloshing-induced oscillations in the motion of the cD galaxy.Comment: 15 pages, 8 figures, 5 tables, A&A in pres

Torsion free groups with indecomposable holonomy group I

We study the torsion free generalized crystallographic groups with the indecomposable holonomy group which is isomorphic to either a cyclic group of order ${p^s}$ or a direct product of two cyclic groups of order ${p}$.Comment: 22 pages, AMS-Te