Very large array H53α and H92α line observations of the central region of NGC 253

We present new VLA observations toward NGC 253 of the recombination line H53α (43 GHz) at an angular resolution of 1".5 × 1".0. The free-free emission at 43 GHz is estimated to be ~140 mJy, implying a star formation rate of 2 M⊙ yr-1 in the nuclear region of this starburst galaxy. A reanalysis is made for previously reported H92α observations carried out with angular resolution of 1".5 × 1".0 and 0".36 × 0".21. Based on the line and continuum emission models used for the 1".5 × 1".0 angular resolution observations, the RRLs H53α and H92α are tracers of the high-density (~105 cm-3) and low-density (~103 cm-3) thermally ionized gas components in NGC 253, respectively. The velocity fields observed in the H53α and H92α lines (1".5 × 1".0) are consistent. The velocity gradient in the central ~18 pc of the NE component, as observed in both the H53α and H92α lines, is in the opposite direction to the velocity gradient determined from the CO observations. The enclosed virial mass, as deduced from the H53α velocity gradient over the NE component, is ~5 × 106 M⊙ in the central ~18 pc region. The H92α line observations at high angular resolution (0".36 × 0".21) reveal a larger velocity gradient, along a P.A. ~ -45° on the NE component, of ~110 km s-1 arcsec-1. The dynamical mass estimated using the high angular resolution H92α data (~7 × 106 M⊙) supports the existence of an accreted massive object in the nuclear region of NGC 253

VLA H53alpha observations of the central region of the Super Star Cluster Galaxy NGC 5253

We present observations in the H53alpha line and radio continuum at 43 GHz carried out with the VLA in the D array (2'' angular resolution) toward the starburst galaxy NGC 5253. VLA archival data have been reprocessed to produce a uniform set of 2, 1.3 and 0.7 cm high angular (0.''2 X 0.''1) radio continuum images. The RRL H53alpha, a previously reported measurement of the H92alpha RRL flux density and the reprocessed high angular resolution radio continuum flux densities have been modeled using a collection of HII regions. Based on the models, the ionized gas in the nuclear source has an electron density of ~6 X 10^4 cm^-3 and an volume filling factor of 0.05. A Lyman continuum photon production rate of 2 X 10^52 s^-1 is necessary to sustain the ionization in the nuclear region. The number of required O7 stars in the central 1.5 pc of the supernebula is ~ 2000. The H53alpha velocity gradient 10 km s^-1 arcsec^-1) implies a dynamical mass of ~3X10^5 Msun; this mass suggests the supernebula is confined by gravity.Comment: Accepted in Astrophysical Journal 7 figure

Tuits saludables: El uso e importancia de Twitter para la prevención en salud

Social media platforms have changed the way people stayinformed, communicate with others, and share ideas. These interactive social platforms are used for many purposes from being in contact with family and friends to promote products and services. However, little is known about the use and importance of social media for health prevention, especially for communication among Hispanic communities.The purpose of this paper is to analyze how social media platforms, especially Twitter, are used for health prevention and communication in Hispanic communities. In doing so, a quantitative content analysis was performed on 3000 tweets with the hashtag #prevención (prevention). Results indicate that most of the prevention messages shared among organizations and users on Twitter were informational messages and very few users promoted interactive communication and mobilization. Mass media and governmental institutions posted more messages to encourage health prevention, especially about publichealth and healthy cities. This study stresses the many social media platforms’ potentialities and functionalities, especially Twitter, that contribute to health prevention and communication. Findings are useful for organizations and users when planning prevention content or campaigns through these platforms.Las redes sociales han cambiado la manera como las personas se informan, comunican y comparten ideas. Estas plataformas sociales se usan para muchos fines, desde estar en contacto con familiares y amigos hasta promocionar productos. Sin embargo, muy poco se conoce sobre su utilidad para la comunicación y prevención en salud, principalmente en comunidades de habla hispana. En ese sentido, esta investigación analiza el empleo e importancia de las redes sociales como herramienta para la prevención de problemas relacionados con la salud en comunidades hispanas. Para ello, desarrolla una metodología cuantitativa y realiza un análisis de contenido de 3000 mensajes en Twitter con el hashtag #prevención. Los resultados indicaron que la mayoría de los mensajes de prevención fueron unidireccionales y muy pocos usuarios promovieron la comunicación y la movilización. Los medios de comunicación y las agencias gubernamentales fueron los usuarios que más enviaron mensajes, principalmente, sobre temas relacionados con la salud pública y vial. Este estudio resalta las diversas potencialidades y funcionalidades de las redes sociales, específicamente Twitter, para contribuir a la prevención y comunicación en salud. Sus hallazgos son útiles al momento de llevar a cabo campañas o contenido de prevención a través de estas plataformas

VLA H53alpha radio recombination line observations of the ultraluminous infrared galaxy Arp 220

We present high angular resolution (0.7'') observations made with the Very Large Array (VLA) of the radio recombination line (RRL) H53alpha and radio continuum emission at 43 GHz from the ultraluminous infrared galaxy (ULIRG) Arp 220. The 43 GHz continuum emission shows a compact structure (~2'') with two peaks separated by ~1'', the East (E) and West (W) components, that correspond to each galactic nucleus of the merger. The spectral indices for both the E and W components, using radio continuum images at 8.3 and 43 GHz are typical of synchrotron emission (alpha ~ -1.0). Our 43 GHz continuum and H53alpha line observations confirm the flux densities predicted by the models proposed by Anantharamaiah et al. This agreement with the models implies the presence of high-density (~ 100,000 cm^-3) compact HII regions (~ 0.1 pc) in Arp 220. The integrated H53alpha line emission is stronger toward the non-thermal radio continuum peaks, which are also coincident with the peaks of molecular emission of the H2CO. The coincidence between the integrated H53alpha and the H2CO maser line emission suggests that the recent star forming regions, traced by the high density gas, are located mainly in regions that are close to the two radio continuum peaks. A velocity gradient of ~ 0.30 km/s/pc in the H53alpha RRL is observed toward the E component and a second velocity gradient of ~ 0.15 km/s/pc is detected toward the W component. The orientations of these velocity gradients are in agreement with previous CO, HI and OH observations. The kinematics of the high-density ionized gas traced by the H53alpha line are consistent with two counter rotating disks as suggested by the CO and HI observations.Comment: The original version was published in the ApJ,633,198,2005. This new version is submitted with the corrected velocity scal

VLA H53alpha and H92alpha line observations of the central region of NGC 253

We present new Very Large Array (VLA) observations toward NGC 253 of the recombination line H53alpha (43 GHz) at an angular resolution of 1.''5 X 1.''0. The free-free emission at 43 GHz is estimated to be ~100 mJy, implying a star formation rate of ~1.3 Msun/yr in the nuclear region of this starburst galaxy. A reanalysis is made for previously reported H92alpha observations carried out with angular resolution of 1.''5 X 1.''0 and 0.''36 X 0.''21. Based on the line and continuum emission models used for the 1.''5 X 1.''0 angular resolution observations, the RRLs H53alpha and H92alpha are tracers of the high-density (~10^5 cm-3) and low-density (~10^3 cm^-3) thermally ionized gas components in NGC 253, respectively. The velocity fields observed in the H53alpha and H92alpha lines 1.''5 X 1.''0) are consistent. The velocity gradient in the central ~18 pc of the NE component, as observed in both the H53alpha and H92alpha lines, is in the opposite direction to the velocity gradient determined from the CO observations. The enclosed virial mass, as deduced from the H53alpha velocity gradient over the NE component, is ~5 X 10^6 Msun in the central ~18 pc region. The H92alpha line observations at high angular resolution (0.''36 X 0.''21) reveal a larger velocity gradient, along a P.A. ~ -45 deg on the NE component, of ~110 km/s/arcsec. The dynamical mass estimated using the high angular resolution H92alpha data (~7 X 10^6 Msun) supports the existence of an accreted massive object in the nuclear region of NGC 253.Comment: Accepted for publication in Ap

Weekday and weekend patterns of physical activity and sedentary time among Liverpool and Madrid youth

Levels of physical inactivity and sedentary behaviour among English and Spanish youth are high and vary within different regions of each country. Little though is known about these during specific periods of the day. The purpose of this study was to describe physical activity (PA) and sedentary time during segments of the day and week, and compare these critical contexts between youth in the Liverpool and Madrid areas of England and Spain, respectively. PA was objectively assessed in 235 Liverpool- and 241 Madrid youth (aged 10-14 years) who wore accelerometers for seven consecutive days. Minutes of sedentary time, moderate PA, vigorous PA and moderate-to-vigorous physical activity (MVPA) were calculated for weekdays, weekend days, school time, non-school time and after-school. Between-country differences were analysed using analysis of covariance (ANCOVA). Madrid youth spent significantly more time in sedentary activities than their Liverpool counterparts. Madrid youth engaged in more minutes of moderate intensity physical activity (MPA) than Liverpool youth during weekdays, school time and non-school time (P < 0.01). Liverpool children recorded more time in vigorous physical activity (VPA) than Madrid peers during week days and weekend days (P < 0.01) and during school time and after-school periods (P < 0.01). The MVPA was significantly higher among Madrid youth during non-school time (P < 0.01). Around 25% of all youth achieved recommended levels of MVPA. Low levels of MVPA and systematic differences in sedentary time, MPA and VPA exist between Liverpool and Madrid youth. Interventions targeted at the least-active children during weekends, after-school and non-school periods within the cultural contexts common to each city are required. © 2013 © 2013 European College of Sport Science

Final NOMAD results on nu_mu->nu_tau and nu_e->nu_tau oscillations including a new search for nu_tau appearance using hadronic tau decays

Results from the nu_tau appearance search in a neutrino beam using the full NOMAD data sample are reported. A new analysis unifies all the hadronic tau decays, significantly improving the overall sensitivity of the experiment to oscillations. The "blind analysis" of all topologies yields no evidence for an oscillation signal. In the two-family oscillation scenario, this sets a 90% C.L. allowed region in the sin^2(2theta)-Delta m^2 plane which includes sin^2(2theta)<3.3 x 10^{-4} at large Delta m^2 and Delta m^2 < 0.7 eV^2/c^4 at sin^2(2theta)=1. The corresponding contour in the nu_e->nu_tau oscillation hypothesis results in sin^2(2theta)<1.5 x 10^{-2} at large Delta m^2 and Delta m^2 < 5.9 eV^2/c^4 at sin^2(2theta)=1. We also derive limits on effective couplings of the tau lepton to nu_mu or nu_e.Comment: 46 pages, 16 figures, Latex, to appear on Nucl. Phys.

Search for the exotic Θ+\Theta^+ resonance in the NOMAD experiment

A search for exotic Theta baryon via Theta -> proton +Ks decay mode in the NOMAD muon neutrino DIS data is reported. The special background generation procedure was developed. The proton identification criteria are tuned to maximize the sensitivity to the Theta signal as a function of xF which allows to study the Theta production mechanism. We do not observe any evidence for the Theta state in the NOMAD data. We provide an upper limit on Theta production rate at 90% CL as 2.13 per 1000 of neutrino interactions.Comment: Accepted to European Physics Journal

A Precise Measurement of the Muon Neutrino-Nucleon Inclusive Charged Current Cross-Section off an Isoscalar Target in the Energy Range 2.5 < E_\nu < 40 GeV by NOMAD

We present a measurement of the muon neutrino-nucleon inclusive charged current cross-section, off an isoscalar target, in the neutrino energy range $2.5 \leq E_\nu \leq 40$ GeV. The significance of this measurement is its precision, $\pm 4$% in $2.5 \leq E_\nu \leq 10$ GeV, and $\pm 2.6$% in $10 \leq E_\nu \leq 40$ GeV regions, where significant uncertainties in previous experiments still exist, and its importance to the current and proposed long baseline neutrino oscillation experiments.Comment: 14 pages, 3 figures, submitted to Phys.Lett.