Multiple merging in the Abell cluster 1367

We present a dynamical analysis of the central ~1.3 square degrees of the cluster of galaxies Abell 1367, based on 273 redshift measurements (of which 119 are news). From the analysis of the 146 confirmed cluster members we derive a significantly non-Gaussian velocity distribution, with a mean location C_{BI} = 6484+/-81 km/s and a scale S_{BI} = 891+/-58 km/s. The cluster appears elongated from the North-West to the South-East with two main density peaks associated with two substructures. The North-West subcluster is probably in the early phase of merging into the South-East substructure (~ 0.2 Gyr before core crossing). A dynamical study of the two subclouds points out the existence of a group of star-forming galaxies infalling into the core of the South-East subcloud and suggests that two other groups are infalling into the NW and SE subclusters respectively. These three subgroups contain a higher fraction of star-forming galaxies than the cluster core, as expected during merging events. Abell 1367 appears as a young cluster currently forming at the intersection of two filaments.Comment: 15 pages, 13 figures, 7 tables. Accepted for publication on A&A. High resolution figures at http://goldmine.mib.infn.it/papers/a1367.htm

The Radio Jet Associated with the Multiple V380 Ori System

The giant Herbig-Haro object 222 extends over $\sim$6$'$ in the plane of the sky, with a bow shock morphology. The identification of its exciting source has remained uncertain over the years. A non-thermal radio source located at the core of the shock structure was proposed to be the exciting source. However, Very Large Array studies showed that the radio source has a clear morphology of radio galaxy and a lack of flux variations or proper motions, favoring an extragalactic origin. Recently, an optical-IR study proposed that this giant HH object is driven by the multiple stellar system V380 Ori, located about 23$'$ to the SE of HH 222. The exciting sources of HH systems are usually detected as weak free-free emitters at centimeter wavelengths. Here we report the detection of an elongated radio source associated with the Herbig Be star or with its close infrared companion in the multiple V380 Ori system. This radio source has the characteristics of a thermal radio jet and is aligned with the direction of the giant outflow defined by HH~222 and its suggested counterpart to the SE, HH~1041. We propose that this radio jet traces the origin of the large scale HH outflow. Assuming that the jet arises from the Herbig Be star, the radio luminosity is a few times smaller than the value expected from the radio-bolometric correlation for radio jets, confirming that this is a more evolved object than those used to establish the correlation.Comment: 13 pages, 3 figure

Level and length of cyclic solar activity during the Maunder minimum as deduced from the active day statistics

The Maunder minimum (MM) of greatly reduced solar activity took place in 1645-1715, but the exact level of sunspot activity is uncertain as based, to a large extent, on historical generic statements of the absence of spots on the Sun. Here we aim, using a conservative approach, to assess the level and length of solar cycle during the Maunder minimum, on the basis of direct historical records by astronomers of that time. A database of the active and inactive days (days with and without recorded sunspots on the solar disc respectively) is constructed for three models of different levels of conservatism (loose ML, optimum MO and strict MS models) regarding generic no-spot records. We have used the active day fraction to estimate the group sunspot number during the MM. A clear cyclic variability is found throughout the MM with peaks at around 1655--1657, 1675, 1684 and 1705, and possibly 1666, with the active day fraction not exceeding 0.2, 0.3 or 0.4 during the core MM, for the three models. Estimated sunspot numbers are found very low in accordance with a grand minimum of solar activity. We have found, for the core MM (1650-1700), that: (1) A large fraction of no-spot records, corresponding to the solar meridian observations, may be unreliable in the conventional database. (2) The active day fraction remained low (below 0.3-0.4) throughout the MM, indicating the low level of sunspot activity. (3) The solar cycle appears clearly during the core MM. (4) The length of the solar cycle during the core MM appears $9\pm 1$ years, but there is an uncertainty in that. (5) The magnitude of the sunspot cycle during MM is assessed to be below 5-10 in sunspot numbers; A hypothesis of the high solar cycles during the MM is not confirmed.Comment: Accepted to Astron. Astrophy

A case report: Giant early gastric cancer

Indexación: Scopus; Scielo.Introducción: El cáncer gástrico es la primera causa de muerte por cáncer, en hombres, en Chile, siendo el adenocarcinoma la variante más frecuente. Caso clínico: Reportamos el caso de un cáncer gástrico incipiente gigante de 7,2 cm en un hombre de 74 años tratado en la Clínica INDISA en Santiago de Chile. El paciente fue sometido exitosamente a una gastrectomía total con linfoadenectomía D2 y esófago-yeyuno anastomosis en Y de Roux. La histología evidenció un adenocarcinoma bien diferenciado, polipoide, invasivo hasta la submucosa, sin compromiso ganglionar. A los 5 años de su cirugía, el paciente se encuentra asintomático y sin recidiva tumoral.https://www.sciencedirect.com/science/article/pii/S0379389316301600?via%3Dihu

V-Shape Liquid Crystal-Based Retromodulator Air to Ground Optical Communications

This paper describes the use of a 2D liquid crystal retro-modulator as a free space, wireless, optical link. The retro-modulator is made up of a retro-reflecting cornercube onto which 2 cascaded V-shape smectics liquid crystal modulators are mounted. The communication link differs with respect to more conventional optical links in not using amplitude (nor frequency) modulation, but instead state-of-polarisation (SOP) modulation known as Polarisation Shift Keying (PolSK). PolSK has the advantage over amplitude modulation, that it is less sensitive to changes in the visibility of the atmosphere, and increases inherently the bandwidth of the link. The implementation of PolSK both in liquid crystal based and in retro-modulated communication are novelties

Effects of core auditory cortex deactivation on neuronal response to simple and complex acoustic signals in the contralateral anterior auditory field

Interhemispheric communication has been implicated in various functions of sensory signal processing and perception. Despite ample evidence demonstrating this phenomenon in the visual and somatosensory systems, to date, limited functional assessment of transcallosal transmission during periods of acoustic signal exposure has hindered our understanding of the role of interhemispheric connections between auditory cortical fields. Consequently, the present investigation examines the impact of core auditory cortical field deactivation on response properties of contralateral anterior auditory field (AAF) neurons in the felis catus. Single-unit responses to simple and complex acoustic signals were measured across AAF before, during, and after individual and combined cooling deactivation of contralateral primary auditory cortex (A1) and AAF neurons. Data analyses revealed that on average: 1) interhemispheric projections from core auditory areas to contralateral AAF neurons are predominantly excitatory, 2) changes in response strength vary based on acoustic features, 3) A1 and AAF projections can modulate AAF activity differently, 4) decreases in response strength are not specific to particular cortical laminae, and 5) contralateral inputs modulate AAF neuronal response thresholds. Collectively, these observations demonstrate that A1 and AAF neurons predominantly modulate AAF response properties via excitatory projections

The star formation properties of disk galaxies: Halpha imaging of galaxies in the Coma supercluster

We present integrated H alpha measurements obtained from imaging observations of 98 late-type galaxies, primarily selected in the Coma supercluster. These data, combined with H alpha photometry from the literature, include a magnitude selected sample of spiral (Sa to Irr) galaxies belonging to the "Great Wall" complete up to mp=15.4, thus composed of galaxies brighter than Mp=-18.8 (H0=100 km Mpc^-1 s^-1). The frequency distribution of the H alpha E.W., determined for the first time from an optically complete sample, is approximately gaussian peaking at E.W. ~25 A. We find that, at the present limiting luminosity, the star formation properties of spiral+Irr galaxies members of the Coma and A1367 clusters do not differ significantly from those of the isolated ones belonging to the Great Wall. The present analysis confirms the well known increase of the current massive star formation rate (SFR) with Hubble type. Moreover perhaps a more fundamental anticorrelation exists between the SFR and the mass of disk galaxies: low-mass spirals and dwarf systems have present SFRs ~50 times higher than giant spirals. This result is consistent with the idea that disk galaxies are coeval, evolve as "closed systems" with exponentially declining SFR and that the mass of their progenitor protogalaxies is the principal parameter governing their evolution. Massive systems having high initial efficiency of collapse, or a short collapse time-scale, have retained little gas to feed the present epoch of star formation. These findings support the conclusions of Gavazzi & Scodeggio (1996) who studyed the color-mass relation of a local galaxy sample and agree with the analysis by Cowie et al. (1996) who traced the star formation history of galaxies up to z>1.Comment: 13 pages (LateX) + 24 figures + 4 tables. To appear in Astronomical Journal, April 1998 issu

B-physics from the ratio method with Wilson twisted mass fermions

We present a precise lattice QCD determination of the b-quark mass, of the B and Bs decay constants and first preliminary results for the B-mesons bag parameter. Simulations are performed with Nf = 2 Wilson twisted mass fermions at four values of the lattice spacing and the results are extrapolated to the continuum limit. Our calculation benefits from the use of improved interpolating operators for the B-mesons and employs the so-called ratio method. The latter allows a controlled interpolation at the b-quark mass between the relativistic data around and above the charm quark mass and the exactly known static limit.Comment: 7 pages, 4 figures, 1 table. Proceedings of the 30th International Symposium on Lattice Field Theory - Lattice 2012; June 24-29, 2012; Cairns, Australi