Visualization, Exploration and Data Analysis of Complex Astrophysical Data

In this paper we show how advanced visualization tools can help the researcher in investigating and extracting information from data. The focus is on VisIVO, a novel open source graphics application, which blends high performance multidimensional visualization techniques and up-to-date technologies to cooperate with other applications and to access remote, distributed data archives. VisIVO supports the standards defined by the International Virtual Observatory Alliance in order to make it interoperable with VO data repositories. The paper describes the basic technical details and features of the software and it dedicates a large section to show how VisIVO can be used in several scientific cases.Comment: 32 pages, 15 figures, accepted by PAS

VisIVO - Integrated Tools and Services for Large-Scale Astrophysical Visualization

VisIVO is an integrated suite of tools and services specifically designed for the Virtual Observatory. This suite constitutes a software framework for effective visual discovery in currently available (and next-generation) very large-scale astrophysical datasets. VisIVO consists of VisiVO Desktop - a stand alone application for interactive visualization on standard PCs, VisIVO Server - a grid-enabled platform for high performance visualization and VisIVO Web - a custom designed web portal supporting services based on the VisIVO Server functionality. The main characteristic of VisIVO is support for high-performance, multidimensional visualization of very large-scale astrophysical datasets. Users can obtain meaningful visualizations rapidly while preserving full and intuitive control of the relevant visualization parameters. This paper focuses on newly developed integrated tools in VisIVO Server allowing intuitive visual discovery with 3D views being created from data tables. VisIVO Server can be installed easily on any web server with a database repository. We discuss briefly aspects of our implementation of VisiVO Server on a computational grid and also outline the functionality of the services offered by VisIVO Web. Finally we conclude with a summary of our work and pointers to future developments

Accuracy of a Wrist-Worn Heart Rate Sensing Device during Elective Pediatric Surgical Procedures

The reliability of wearable photoplethysmography (PPG) sensors to measure heart rate (HR) in hospitalized patients has only been demonstrated in adults. We evaluated the accuracy of HR monitoring with a personal fitness tracker (PFT) in children undergoing surgery. HR monitoring was performed using a wrist-worn PFT (Fitbit Charge HR) in 30 children (8.21 \ub1 3.09 years) undergoing laparoscopy (n = 8) or open surgery (n = 22). HR values were analyzed preoperatively and during surgery. The accuracy of HR recordings was compared with measurements recorded during continuous electrocardiographic (cECG) monitoring; HRs derived from continuous monitoring with pulse oximetry (SpO2R) were used as a positive control. PFT-derived HR values were in agreement with those recorded during cECG (r = 0.99) and SpO2R (r = 0.99) monitoring. PFT performance remained high in children < 8 years (r = 0.99), with a weight < 30 kg (r = 0.99) and when the HR was < 70 beats per minute (bpm) (r = 0.91) or > 140 bpm (r = 0.99). PFT accuracy was similar during laparoscopy and open surgery, as well as preoperatively and during the intervention (r > 0.9). PFT-derived HR showed excellent accuracy compared with HRs measured by cECG and SpO2R during pediatric surgical procedures. Further clinical evaluation is needed to define whether PFTs can be used in different health care settings

Granulicatella spp., a Causative Agent of Infective Endocarditis in Children

Granulicatella spp. are non-motile, non-sporulating, facultatively anaerobic Gram-positive cocci. Throughout the literature, these organisms have been referred to by several names, such as “nutritionally deficient streptococci”, “vitamin-B dependent streptococci” and “pyridoxal-dependent streptococci”, because of their fastidious nutritional requirements, which can often make culture isolation challenging. Known to be a member of the normal microbiota of the human oral cavity and urogenital and intestinal tracts, similar to other streptococci, Granulicatella spp. can cause bacteremia, sepsis and infective endocarditis. Considering the difficulty in growing this organism on culture medium, the fact that it is now included among the bacteria known to be responsible for culture-negative infective endocarditis suggests that its pathogenic role could be highly underestimated. Moreover, being considered such a rare causative agent, it is not a target of standard antibiotic empiric treatment. We present a rare case of G. elegans endocarditis in a young child and review the medical literature on Granulicatella endocarditis in the pediatric population, with the aim of sharing knowledge about this microorganism, which can be challenging for a clinician who is not familiar with it

Left Ventricular Deformation and Myocardial Work Parameters in Patients with Hereditary Transthyretin Amyloidosis Treated with Patisiran: A Single-Center Study

Background: In recent years, many advances have been made in the treatment of hereditary transthyretin amyloidosis (ATTRv). Patisiran is a small-interfering RNA used to treat ATTRv with only polyneuropathy or polyneuropathy and cardiomyopathy. The aim of our study was to assess the effect of patisiran on cardiac function in ATTRv patients using speckle tracking echocardiography (STE) analysis. Methods: A single-center prospective study was performed enrolling 21 patients with ATTRv (11 M—52% of the population; 10 F—48% of the population; median age 66 ± 8.4 years old). A total of 7 patients had cardiac amyloidosis and polyneuropathy, and 14 patients had only polyneuropathy without cardiac involvement. Cardiological evaluation including electrocardiograms, echocardiography with STE, and assessment of myocardial work parameters was performed in all patients before starting patisiran and after 9–18 months. Functional capacity was assessed using the 6 min walk test; quality of life was assessed using the Kansas City Cardiomyopathy Questionnaire (KCCQ). Results: We did not find a significant difference in gender prevalence of ATTR amyloidosis in all of the population (p-value 0.79), but we found that cardiac amyloidosis significantly predominated in the male sex compared to patients with only neuropathy. In all patients, we found a slight improvement in functional capacity and quality of life. We did not find significant changes in left ventricular ejection fraction (LVEF), but we found a significant improvement in left ventricular global longitudinal strain (GLS), global work waste (GWW), and global work efficiency (GWE), especially in patients with cardiac amyloidosis; E/e’ average and left atrial stiffness also improved significantly in patients with cardiac amyloidosis. Conclusions: Our study confirms a positive effect of patisiran on cardiac function, particularly the absence of signs of subclinical deterioration as detected by very sensitive STE parameters such as GLS, MW, and atrial stiffness during follow up in patients treated with patisiran

Proapoptotic effect of atorvastatin on stimulated rabbit smooth muscle cells

The in vitro and in vivo activity of atorvastatin and other 3-hydroxy-3-methylglutaryl coenzyme A (HMGCoA) reductase inhibitors (fluvastatin, pravastatin and simvastatin) has been investigated. Atorvastatin, fluvastatin, pravastatin and simvastatin caused a significant and dose-dependent (0.1-50 microM) reduction in cell multiplication of vascular smooth muscle cells (SMC) in cultures associated with the retardation of cycling cells in the G1 and G2/M compartments at 24 h, a phenomenon leading to apoptosis (programmed cell death) in several experimental in vitro models. The effects on the cell cycle resulted in a strong inhibition of cell proliferation at 48 h, followed by apoptosis when incubation was prolonged to 72 h as assessed by nuclei morphology and cytofluorimetric analysis of DNA. The apoptotic effect observed for the statins is completely prevented by the addition of exogenous mevalonate at a 100 microm concentration. in vivo SMC proliferation was stimulated by applying a silastic collar to the outside surface of carotid arteries in normocholesterolemic rabbits in the presence of an anatomically intact endothelium. The positioning of the collar promoted apoptosis in control vessels as assessed by Terminal Deoxynucleotidyl Transferase-dUTP-Biotin Nick-End Labeling (TUNEL) assay. The pre-treatment with 5 mg kg-1 per day of atorvastatin before collar insertion strongly increased the number of TUNEL-positive cells, suggesting a pro-apoptotic effect of HMGCoA reductase inhibitors also in vivo, even though cell DNA rearrangement still needs to be excluded. No apoptotic signal was detectable in sham operated arteries with no collar in either control or atorvastatin-treated rabbits. These data indicate that HMGCoA reductase inhibitors effect on the arterial wall may involve the modulation of both cell proliferation and programmed cell deaths supporting a possible role of statins in the prevention of early lesion and restenosis

Massive and refined: a sample of large galaxy clusters simulated at high resolution. I:Thermal gas and shock waves properties

We present a sample of 20 massive galaxy clusters with total virial masses in the range of 6 10^14 M_sol<M(vir)< 2 10^15M_sol, re-simulated with a customized version of the 1.5. ENZO code employing Adaptive Mesh Refinement. This technique allowed us to obtain unprecedented high spatial resolution (25kpc/h) up to the distance of 3 virial radii from the clusters center, and makes it possible to focus with the same level of detail on the physical properties of the innermost and of the outermost cluster regions, providing new clues on the role of shock waves and turbulent motions in the ICM, across a wide range of scales. In this paper, a first exploratory study of this data set is presented. We report on the thermal properties of galaxy clusters at z=0. Integrated and morphological properties of gas density, gas temperature, gas entropy and baryon fraction distributions are discussed, and compared with existing outcomes both from the observational and from the numerical literature. Our cluster sample shows an overall good consistency with the results obtained adopting other numerical techniques (e.g. Smoothed Particles Hydrodynamics), yet it provides a more accurate representation of the accretion patterns far outside the cluster cores. We also reconstruct the properties of shock waves within the sample by means of a velocity-based approach, and we study Mach numbers and energy distributions for the various dynamical states in clusters, giving estimates for the injection of Cosmic Rays particles at shocks. The present sample is rather unique in the panorama of cosmological simulations of massive galaxy clusters, due to its dynamical range, statistics of objects and number of time outputs. For this reason, we deploy a public repository of the available data, accessible via web portal at http://data.cineca.it.Comment: 26 pages, 20 figures, New Astronomy accepted. Reference list updated. Higher quality versions of the paper can be found at: http://www.ira.inaf.it/~vazza/papers A public archive of galaxy clusters data is accessible at http://data.cineca.it

Magnetic activity in the photosphere of CoRoT-Exo-2a. Active longitudes and short-term spot cycle in a young Sun-like star

Copyright © The European Southern Observatory (ESO)Context. The space experiment CoRoT has recently detected transits by a hot Jupiter across the disc of an active G7V star (CoRoTExo-2a) that can be considered as a good proxy for the Sun at an age of approximately 0.5 Gyr. Aims. We present a spot modelling of the optical variability of the star during 142 days of uninterrupted observations performed by CoRoT with unprecedented photometric precision. Methods. We apply spot modelling approaches previously tested in the case of the Sun by modelling total solar irradiance variations, a good proxy for the optical flux variations of the Sun as a star. The best results in terms of mapping of the surface brightness inhomogeneities are obtained by means of maximum entropy regularized models. To model the light curve of CoRoT-Exo-2a, we take into account the photometric effects of both cool spots and solar-like faculae, adopting solar analogy. Results. Two active longitudes initially on opposite hemispheres are found on the photosphere of CoRoT-Exo-2a with a rotation period of 4.522 ± 0.024 days. Their separation changes by ≈80◦ during the time span of the observations. From this variation, a relative amplitude of the surface differential rotation lower than ~1 percent is estimated. Individual spots form within the active longitudes and show an angular velocity ~1 percent lower than that of the longitude pattern. The total spotted area shows a cyclic oscillation with a period of 28.9 ± 4.3 days, which is close to 10 times the synodic period of the planet as seen by the rotating active longitudes. We discuss the effects of solar-like faculae on our models, finding indications of a facular contribution to the optical flux variations of CoRoT-Exo-2a being significantly smaller than in the present Sun. Conclusions. The implications of such results for the internal rotation of CoRoT-Exo-2a are discussed, based on solar analogy. A possible magnetic star-planet interaction is suggested by the cyclic variation of the spotted area. Alternatively, the 28.9-d cycle may be related to Rossby-type waves propagating in the subphotospheric layers of the star

A Tale of Two Markets: How Lower-end Borrowers Are Punished for Bank Regulatory Failures in Nigeria

In 2009, the Nigerian banking system witnessed a financial crisis caused by elite borrowers in the financial market. Regulatory response to the Nigerian crisis closely mirrored the international response with increased capital and liquidity thresholds for commercial banks. While the rise of consumer protection on the agenda of prudential supervisors internationally was logical in that consumer debt was the main cause of the global recession, the Nigerian banking reforms of 2009 disproportionately affected access by poorer consumers, who ironically had little to do with the underlying causes of the crisis. As lending criteria become more stringent, poorer consumers of credit products are pushed into informal markets because of liquidity-induced credit rationing. Overall, consumer protection is compromised because stronger consumer protection rules for the formal sector benefits borrowers from formal institutions who constitute the minority of borrowers in all markets. While the passage of regulation establishing credit bureaux and the National Collateral Registry will, in theory, ease access to credit especially by lower-end borrowers, the vast size of the informal market continues to compound the information asymmetry problem, fiscal policies to tackle structural economic issues such as unemployment and illiteracy remain to be initiated, and bank regulators continue to pander to elite customers with policy responses that endorse too big to fail but deems lower-end consumers too irrelevant to save. The essay concluded that addressing the wide disparity in access to credit between the rich and poor through property rights reforms to capture the capital of the informal class, promoting regulation to check loan concentration, and stimulating competition by allowing Telecommunication Companies (TELCOs) and fintech companies to carry on lending activities because of their superior knowledge of lower-end markets will facilitate greater access. The risk of systemic failure deriving from consumer credit in Nigeria is insignificant compared to the consumer vulnerabilities resulting from the exposure of consumers to unregulated products in the informal market