Distances on Cosmological Scales with VLTI

We present here a new method using interferometric measurements of quasars, that allows the determination of direct geometrical distances on cosmic scales. Quasar Broad Emission Line Regions sizes provide a "meter rule" with which to measure the metric of the Universe. This method is less dependent of model assumptions, and even of variations in the fundamental constants (other than c). We discuss the spectral and spatial requirements on the VLTI observations needed to carry out these measurements.Comment: 6 pages, 2 postscript figures, to appear in the proceedings of the JENAM 2002 Workshop WS-VLTI "The Very Large Telescope Interferometer: Challenges for the Future", Editors: P.J.V. Garcia, A. Glindemann, Th. Henning, F. Malbet, Ap&SS, Kluwer, in pres

Gamification in higher education and stem : a systematic review of literature

In recent years, gamification, the use of game elements in non-game contexts, has drawn the attention of educators due to the possibility of making learning more motivating and engaging; this led to an increase of research in the field. Despite the availability of literature reviews about gamification and its effects, no work to this date has focused exclusively on Higher Education (HE). Next, worldwide there is an increasing demand for skilled Science, Technology, Engineering and Mathematics (STEM) professionals that meet the challenges related to scientific and technological innovations of the 21st Century. This lead to the need of strengthening STEM Higher Education. This brings us to the purpose of this work: presenting a systematic literature review of empirical studies about gamification STEM related Higher Education. This review study started from a systematic mapping design of 'Web of Science' articles, with following inclusion criteria: empirical gamification studies set up in HE, published between 2000 and 2016; focusing on undergraduate or graduate students; in the STEM knowledge field, and set up in authentic settings. An initial search resulted in 562 potentially relevant articles. After applying all selection criteria, only 18 studies could be retained. 12 additional articles were included by analyzing references from earlier literature reviews, resulting in 30 studies to be included. Analysis results show how a combination of game elements (e.g. leaderboards, badges, points and other combinations) positively affects students' performance, attendance, goal orientation and attitude towards mostly computer science related subjects. The analysis results also point at a lack of studies in certain STEM areas, a lack of studies that identify the particular game element associated with the positive differential impact on student performance; a lack of validated psychometric measurements, and lack of focus on student variables that could/should be taken into account as mediating/moderating variables clarifying the impact of gamification in the HE focus on STEM learning and teaching

CHEERS results on Mrk 573: Study of deep Chandra observations

We present results on Mrk 573 obtained as part of the CHandra survey of Extended Emission-line Regions in nearby Seyfert galaxies (CHEERS). Previous studies showed that this source features a biconical emission in the soft X-ray band closely related with the Narrow Line Region as mapped by the [O iii] emission line and the radio emission, though on a smaller scale; we investigate the properties of soft X-ray emission from this source with new deep Chandra observations. Making use of the subpixel resolution of the Chandra/ACIS image and PSF-deconvolution, we resolve and study substructures in each ionizing cone. The two cone spectra are fitted with photoionization model, showing a mildly photoionized phase diffused over the bicone. Thermal collisional gas at about ~ 1.1 keV and ~ 0.8 keV appears to be located between the nucleus and the "knots" resolved in radio observations, and between the "arcs" resolved in the optical images, respectively; this can be interpreted in terms of shock interaction with the host galactic plane. The nucleus shows a significant flux decrease across the observations indicating variability of the AGN, with the nuclear region featuring higher ionization parameter with respect to the bicone region. The long exposure allows us to find extended emission up to ~ 7 kpc from the nucleus along the bicone axis. Significant emission is also detected in the direction perpendicular to the ionizing cones, disagreeing with the fully obscuring torus prescribed in the AGN unified model, and suggesting instead the presence of a clumpy structure.Comment: 38 pages, 15 figures, 8 tables, accepted for publication on Ap

The Role of Natriuretic peptides in Renovascular Hypertension and its correlation with the Evolution of Myocardial Hypertrophy

The interactions between pressure and volume overload that occur in hypertension lead to different patterns of cardiac hypertrophy and to increase in natriuretic peptides (NPs). The profiles of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) synthesis and secretion have been investigated in models of hypertension. However, the different evolution of these profiles during the acute and chronic periods of pressure overload-induced cardiac hypertrophy is still unknown. For this reason, we studied one-kidney, one clip model using Sprague-Dawley rats at weeks 2, 4, 6 and 12 and correlated the evolution of these profiles with cardiac hypertrophy and hypertension. We observed a positive correlation between blood pressure elevation and the degree of cardiac hypertrophy, with a time-dependent increase in both parameters from week 2. Levels of BNP expression showed an early increase after 2 weeks of treatment while ANP increased significantly after 6 weeks. Yet, the increase in ANP expression was gradual, allowing its correlation with hypertrophy and hypertension. The NP expression has a differential response in the early stages of the development of hypertrophy induced by the renovascular model, with an early increase in BNP expression. Once hypertrophy develops, BNP expression is no longer specific and the increase of both NPs depends on and correlates with the degree of cardiac hypertrophy.Fil: Cerrudo, Carolina Susana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Cavallero, Carmen Susana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Rodríguez Fermepin, Martin. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Hertig, Cecilia Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Fernandez, Belisario Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentin

Ball hulls, ball intersections, and 2-center problems for gauges

The notions of ball hull and ball intersection of nite sets, important in Banach space theory, are extended from normed planes to generalized normed planes, i.e., to (asymmetric) convex distance functions which are also called gauges. In this more general setting we derive various new results about these notions and their relations to each other. Further on, we extend the known 2-center problem and a modified version of it from the Euclidean situation to norms and gauges or, in other words, from Euclidean circles to arbitrary closed convex curves. We derive algorithmical results on the construction of ball hulls and ball intersections, and computational approaches to the 2-center problem with constrained circles and, in case of strictly convex norms and gauges, for the fixed 2-center problem are also given

Mapping Seyfert and LINER Excitation Modes in the Inner kpc of NGC 3393

We have mapped the extended narrow line region (ENLR) of NGC 3393 on scales of $r\lesssim4^{\prime\prime}$ ($\sim1\,$kpc) from the nucleus using emission line images of H$\alpha\,\lambda6563$, [O III]$\lambda5007$, and [S II]$\lambda\lambda6717,6731$ taken with HST as part of the CHandra survey of Extended Emission line Regions in nearby Seyfert galaxies (CHEERS). By mapping these lines onto a spatially resolved Baldwin-Phillips-Terlevich (BPT) diagram, we investigate the impact of feedback from a Compton-thick AGN on its circumnuclear ISM. We find the expected Seyfert-like emission within the ionization bicone ($\lesssim3^{\prime\prime}$; 770 pc). We also find a new, figure 8 shaped LINER cocoon enveloping the bicone and defining a sharp ($\lesssim100\;$pc) transition between higher and lower ionization zones. These data illustrate the morphological dependence of ionization states of the ENLR relative to bicone and host gas geometries.Comment: Accepted by ApJ and published (2016, ApJ, 829, 46). Updated to reflect the accepted versio

Quasar Parallax: a Method for Determining Direct Geometrical Distances to Quasars

We describe a novel method to determine direct geometrical distances to quasars that can measure the cosmological constant, Lambda, with minimal assumptions. This method is equivalent to geometric parallax, with the `standard length' being the size of the quasar broad emission line region (BELR) as determined from the light travel time measurements of reverberation mapping. The effect of non-zero Lambda on angular diameter is large, 40% at z=2, so mapping angular diameter distances vs. redshift will give Lambda with (relative) ease. In principle these measurements could be made in the UV, optical, near infrared or even X-ray bands. Interferometers with a resolution of 0.01mas are needed to measure the size of the BELR in z=2 quasars, which appear plausible given reasonable short term extrapolations of current technology.Comment: 13 pages, with 3 figures. ApJ Letters, in press (Dec 20, 2002

Development of arbuscular mycorrhizal fungi in the presence of different patterns of Trifolium repens shoot flavonoids

We tested the effects of the flavonoid 3-methoxi-5,6,7,8-hydroxy-4'hydroxy flavone (NMHTV) isolated from shoots of non arbuscular mycorrhizal (AM) inoculated clover, and of the flavonoids 5,6,7,8-hydroxy-3-methoxy flavone (MH-1); 5,6,7,8-hydroxy-4'- hydroxy flavone (MH-2); and 5,7-hydroxy-3,4'-methoxy flavone (MH-3); isolated from AM clover (Trifolium repens) shoots, on spore germination, hyphal length, hyphal branches and the number of cluster of auxiliary cells or the number of secondary spores (Presymbiotic stage) and on the number of entry points and the percentage of AM colonized root of tomato (Lycopersicum esculentum) by the AM fungi Gigaspora rosea, Giaspora margarita, Glomus mosseae and Glomus intraradices (Symbiotic stage). Non significant effects of the flavonoids isolated from the shoot of mycorrhizal colonized clover on the presymbiotic and symbiotic stages of Gigaspora and Glomus endophytes were found. The flavonoid NMHTV isolated from non AM clover shoot, did not affect the percentage of germination of spores but significantly increased (P < 0.05) the other steps of the presymbiotic stage of Gi. margarita spores when 2 μM concentration was used. The symbiotic stage of Gi. margarita was also significantly increased when 2 μM of the flavonoid NMHTV was applied. This flavonoid had no effect on the presymbiotic development of G. mosseae, G. intraradices and Gi. rosea except when 8 μM concentration was used, which inhibited the hyphal length of Gi. rosea. These results suggest the possible implication of the flavonoid NMHTV in the susceptibility of tomato roots to the AM formation by Gi. margarita. The absence of stimulation of the AM presymbiotic and symbiotic stages in tomato by exogenous application of the newly synthesized flavonoids MH-1, MH-2, and MH-3, in clover shoots after AM colonization, indicated that the autorregulation of the AM symbiosis can be, at least partially, due to the disappearance of flavonoids in AM colonized plants that stimulated the AM symbiosis.Fil: Scervino, Jose Martin. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Ponce, María Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Della Mónica, Ivana Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Vierheilig, Horst. Universitat Fur Bodenkultur Wien; Austria. Consejo Superior de Investigaciones Científicas. Estación Experimental del Zaidín; EspañaFil: Ocampo, Juan Antonio. Consejo Superior de Investigaciones Científicas. Estación Experimental del Zaidín; EspañaFil: Godeas, Alicia Margarita. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin