2,104 research outputs found

    Detection of a multi-shell planetary nebula around the hot subdwarf O-type star 2MASS J19310888+4324577

    Full text link
    (Abridged) The origin of hot subdwarf O-type stars (sdOs) remains unclear since their discovery in 1947. Among others, a post-Asymptotic Giant Branch (post-AGB) origin is possible for a fraction of sdOs. We are involved in a comprehensive ongoing study to search for and to analyze planetary nebulae (PNe) around sdOs with the aim of establishing the fraction and properties of sdOs with a post-AGB origin. We use deep Halpha and [OIII] images of sdOs to detect nebular emission and intermediate resolution, long-slit optical spectroscopy of the detected nebulae and their sdO central stars. These data are complemented with other observations for further analysis of the detected nebulae. We report the detection of an extremely faint, complex PN around 2MASS J19310888+4324577 (2M1931+4324), a star classified as sdO in a binary system. The PN shows a bipolar and an elliptical shell, whose major axes are oriented perpendicular to each other, and high-excitation structures outside the two shells. WISE archive images show faint, extended emission at 12 and 22 microns in the inner nebular regions. The internal nebular kinematics is consistent with a bipolar and a cylindrical/ellipsoidal shell, in both cases with the main axis mainly perpendicular to the line of sight. The nebular spectrum only exhibits Halpha, Hbeta and [OIII]4959,5007 emission lines, but suggests a very low-excitation ([OIII]/Hbeta = 1.5), in strong contrast with the absence of low-excitation emission lines. The spectrum of 2M1931+4324 presents narrow, ionized helium absorptions that confirm the previous sdO classification and suggest an effective temperature >= 60000 K. The binary nature of 2M1931+4324, its association with a complex PN, and several properties of the system provide strong support for the idea that binary central stars are a crucial ingredient in the formation of complex PNe.Comment: 8 pages, 7 figures, accepted in Astronomy and Astrophysic

    Consequences of long-distance transport on the behavior and health of young-bulls that may affect their fitness to adapt to feedlots

    Get PDF
    Some studies have shown that long distance journeys and the type of trailer compartment have consequences on farm animal welfare. However, there is little evidence to indicate how these consequences affect the fitness of young bulls to adapt to a novel and challenging environment such as an intensive industrial feedlot. Therefore, the objective of our study was to evaluate the consequences of long-distance transport and trailer compartment on the behavior and health of young bulls during the first 60 days after arrival to the feedlot. An evaluation protocol was conducted to record individual behavior (scan sampling) and health indicators of young bulls from days 1-10 and 51-60 after arrival. In addition, three ocular thermal images were taken per animal in a chute during weighing, one each on day 0, day 2 (48 h) and day 50. From our results, the thermophysiological profile, maintenance behaviors and health indicators suggest that there are two distinct groups of consequences affecting animal fitness during the first two months in the feedlot. The first was linked to post-transport fatigue (PTF) that seemed to disappear after the 10 days post-arrival at feedlot. The second was related to signs of bovine respiratory disease (BRD) that began 6 days post-transport and persisted until day 60. In addition, the trailer compartments known as the belly and the deck were shown to be problematic for animal welfare, where the transport in the belly was linked to fatigue after transport, while transport in the deck was associated with respiratory problems. Our study underscores the importance of applying preconditioning practices in cow-calf rearing systems at least a couple of months prior to the long-distance journey, in addition to implementing good loading practices to select which animals are best suited for a given compartment. Our results may be useful to minimize the impacts of PTF and BRD, to propose best practices for livestock transport in countries with similar production systems and agroecosystems

    Constraints on neutrino-photon interactions from rare Z decays

    Get PDF
    It is shown that the rare decays ZνnuˉγZ \to \nu \bar{nu} \gamma and ZννˉγγZ \to \nu \bar{\nu} \gamma \gamma are useful to put model-independent bounds on neutrino-one-photon and neutrino-two-photon interactions. The results are then used to constrain the τ\tau neutrino magnetic moment and the double radiative decay νjνiγγ\nu_j \to \nu_i \gamma \gamma. It is found that the decay ZνnuˉγZ \to \nu \bar{nu} \gamma gives a more stringent bound on the τ\tau neutrino magnetic moment than that obtained from ZννˉγγZ \to \nu \bar{\nu} \gamma \gamma; the latter decay in turn gives limits on the neutrino-two-photon interaction that are less stringent than those obtained for a sterile neutrino νs\nu_s from the analysis of νμNνsN\nu_\mu N \to \nu_s N conversion.Comment: 11 pages, 5 figures, elsart forma

    At the tip of an iceberg: citizen science and active surveillance collaborating to broaden the known distribution of Aedes japonicus in Spain

    Get PDF
    Background: Active surveillance aimed at the early detection of invasive mosquito species is usually focused on seaports and airports as points of entry, and along road networks as dispersion paths. In a number of cases, however, the first detections of colonizing populations are made by citizens, either because the species has already moved beyond the implemented active surveillance sites or because there is no surveillance in place. This was the case of the first detection in 2018 of the Asian bush mosquito, Aedes japonicus, in Asturias (northern Spain) by the citizen science platform Mosquito Alert. Methods: The collaboration between Mosquito Alert, the Ministry of Health, local authorities and academic researchers resulted in a multi-source surveillance combining active field sampling with broader temporal and spatial citizen-sourced data, resulting in a more flexible and efficient surveillance strategy. Results: Between 2018 and 2020, the joint efforts of administrative bodies, academic teams and citizen-sourced data led to the discovery of this species in northern regions of Spain such as Cantabria and the Basque Country. This raised the estimated area of occurrence of Ae. japonicus from < 900 km2 in 2018 to > 7000 km2 in 2020. Conclusions: This population cluster is geographically isolated from any other population in Europe, which raises questions about its origin, path of introduction and dispersal means, while also highlighting the need to enhance surveillance systems by closely combining crowd-sourced surveillance with public health and mosquito control agencies’ efforts, from local to continental scales. This multi-actor approach for surveillance (either passive and active) shows high potential efficiency in the surveillance of other invasive mosquito species, and specifically the major vector Aedes aegypti which is already present in some parts of Europe. Graphical abstract: [Figure not available: see fulltext.] © 2021, The Author(s)

    Investigación de Candidas en uretra en casos de prurito vulvar

    Get PDF
    Este trabajo ha sido realizado en colaboración con el Servicio de Ginecología de la Residencia Sanitaria "Ruiz de Alda" del S.O.ESe investiga la presencia de Candidas, en 150 muestras uretrales de pacientes que consultan aquejadas de prurito vulvovaginal. Se aislan e identifican 36 especies de Candidas, que corresponden a los tres grupos siguientes: albicans, krusei y tropicalis

    IAA : Información y actualidad astronómica (9)

    Get PDF
    Sumario : Investigación: Las colas de polvo de los cometas.-- Agua en el Universo.-- Ventana Abierta: Sobre la enseñanza de la ciencia en la educación secundaria.-- Charlas con… Max Pettini.-- Actualidad Científica: La luz y los colores de las nebulosas planetarias.-- Magnetares.-- Actividades IAA.-- Agenda.Esta revista se publica con la ayuda de la Acción Especial DIF 2001-4284-E del Programa Nacional de Difusión de la Ciencia y la Tecnología, del Ministerio de Ciencia y Tecnología.Peer reviewe
    corecore