2,921 research outputs found

    Kinematics of the Outflow From The Young Star DG Tau B: Rotation in the vicinities of an optical jet

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    We present 12^{12}CO(2-1) line and 1300 μ\mum continuum observations made with the Submillimeter Array (SMA) of the young star DG Tau B. We find, in the continuum observations, emission arising from the circumstellar disk surrounding DG Tau B. The 12^{12}CO(2-1) line observations, on the other hand, revealed emission associated with the disk and the asymmetric outflow related with this source. Velocity asymmetries about the flow axis are found over the entire length of the flow. The amplitude of the velocity differences is of the order of 1 -- 2 km s1^{-1} over distances of about 300 -- 400 AU. We interpret them as a result of outflow rotation. The sense of the outflow and disk rotation is the same. Infalling gas from a rotating molecular core cannot explain the observed velocity gradient within the flow. Magneto-centrifugal disk winds or photoevaporated disk winds can produce the observed rotational speeds if they are ejected from a keplerian disk at radii of several tens of AU. Nevertheless, these slow winds ejected from large radii are not very massive, and cannot account for the observed linear momentum and angular momentum rates of the molecular flow. Thus, the observed flow is probably entrained material from the parent cloud. DG Tau B is a good laboratory to model in detail the entrainment process and see if it can account for the observed angular momentum.Comment: Accepted to Ap

    An Asymmetric Keplerian Disk Surrounding the O-type Protostar IRAS 16547-4247

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    For the past few decades, there has been great interest in determining if even the most massive stars in our galaxy (namely the spectral O-type stars) are formed in a similar manner as the low- and intermediate-mass stars, that is, through the presence of accreting disks and powerful outflows. Here, using sensitive observations of the Atacama Large Millimeter/Submillimeter Array, we report a resolved Keplerian disk (with 15 synthesized beams across its major axis) surrounding the deeply embedded O-type protostar IRAS 16547-4247. The disk shows some asymmetries that could arise because the disk is unstable and fragmenting or because of different excitation conditions within the disk. The enclosed mass estimated from the disk Keplerian radial velocities is 25 -3 M . The molecular disk is at the base of an ionized thermal radio jet and is approximately perpendicular to the jet axis orientation. We additionally find the existence of a binary system of compact dusty objects at the center of the accreting disk, which indicates the possible formation of an O-type star and a companion of lower mass. This is not surprising due to the high binary fraction reported in massive stars. Subtracting the contribution of the dusty disk plus the envelope and the companion, we estimated a mass of 20 M for the central star.Fil: Zapata, Luis A.. Universidad Nacional Autónoma de México; MéxicoFil: Garay, Guido. Universidad de Chile; ChileFil: Palau, Aina. Universidad Nacional Autónoma de México; MéxicoFil: Rodríguez, Luis F.. Universidad Nacional Autónoma de México; MéxicoFil: Fernandez Lopez, Manuel. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Estalella, Robert. Universidad de Barcelona; EspañaFil: Guzmán, Andres. National Astronomical Observatory of Japan; Japó

    Tidal Interaction between the UX Tauri A/C Disk System Revealed by ALMA

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    We present sensitive and high angular-resolution (∼0.″2-0.″3) (sub)millimeter (230 and 345 GHz) continuum and CO(2-1)/CO(3-2) line archive observations of the disk star system in UX Tauri carried out with the Atacama Large Millimeter/Submillimeter Array. These observations reveal the gas and dusty disk surrounding the young star UX Tauri A with a large signal-to-noise ratio (>400 in the continuum and >50 in the line), and for the first time we detect the molecular gas emission associated with the disk of UX Tauri C (with a size for the disk of <56 au). No (sub)millimeter continuum emission is detected at the 5σ level (0.2 mJy at 0.85 mm) associated with UX Tauri C. For the component UX Tauri C, we estimate a dust disk mass of ≤0.05 M ⊕. Additionally, we report a strong tidal disk interaction between both disks, UX Tauri A/C, separated 360 au in projected distance. The CO line observations reveal marked spiral arms in the disk of UX Tauri A and an extended redshifted stream of gas associated with the UX Tauri C disk. No spiral arms are observed in the dust continuum emission of UX Tauri A. Assuming a Keplerian rotation we estimate the enclosed masses (disk+star) from their radial velocities in 1.4 ± 0.6 M o˙ for UX Tauri A, and 70 ± 30/sin i Jupiter masses for UX Tauri C (the latter coincides with the mass upper limit value for a brown dwarf). The observational evidence presented here lead us to propose that UX Tauri C has a close approach of a possible wide, evolving, and eccentric orbit around the disk of UX Tauri A, causing the formation of spiral arms and a stream of molecular gas falling toward UX Tauri C.Fil: Zapata, Luis A.. Instituto de Radioastronomía y Astrofísica; MéxicoFil: Rodríguez, Luis F.. Instituto de Radioastronomía y Astrofísica; México. Universidad Autónoma de Chiapas; MéxicoFil: Fernandez Lopez, Manuel. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Palau, Aina. Instituto de Radioastronomía y Astrofísica; MéxicoFil: Estalella, Robert. Universidad de Barcelona; EspañaFil: Osorio, Mayra. Instituto de Astrofísica de Andalucía; EspañaFil: Anglada, Guillem. Instituto de Astrofísica de Andalucía; EspañaFil: Huelamo, Nuria. Centro de Astrobiología (csic-inta); Españ

    A de novo complete BRCA1 gene deletion identified in a Spanish woman with early bilateral breast cancer

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    <p>Abstract</p> <p>Background</p> <p>Germline mutations in either of the two tumor-suppressor genes, <it>BRCA1 </it>and <it>BRCA2</it>, account for a significant proportion of hereditary breast and ovarian cancer cases. Most of these mutations consist of deletions, insertions, nonsense mutations, and splice variants, however an increasing number of large genomic rearrangements have been identified in these genes.</p> <p>Methods</p> <p>We analysed <it>BRCA1 </it>and <it>BRCA2 </it>genes by direct sequencing and MLPA. We confirmed the results by an alternative MLPA kit and characterized the <it>BRCA1 </it>deletion by Array CGH.</p> <p>Results</p> <p>We describe the first case of a patient with no strong family history of the disease who developed early-onset bilateral breast cancer with a <it>de novo </it>complete <it>BRCA1 </it>gene deletion in the germinal line. The detected deletion started from the region surrounding the <it>VAT1 </it><it>locus </it>to the beginning of <it>NBR1 </it>gene, including the <it>RND2</it>, Ψ<it>BRCA1</it>, <it>BRCA1 </it>and <it>NBR2 </it>complete genes.</p> <p>Conclusion</p> <p>This finding supports the large genomic rearrangement screening of <it>BRCA </it>genes in young breast cancer patients without family history, as well as in hereditary breast and ovarian cancer families previously tested negative for other variations.</p

    Catching the Butterfly and the Homunculus of n Carinae with ALMA

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    The nature and origin of the molecular gas component located in the circumstellar vicinity of n Carinae are still far from being completely understood. Here, we present Atacama Large Millimeter/submillimeter Array CO(3-2) observations with a high angular resolution (∼0.″15) and a great sensitivity that are employed to reveal the origin of this component in n Carinae. These observations reveal much higher velocity (-300 to +270 km s-1) blue- and redshifted molecular thermal emission than previously reported, which we associate with the lobes of the Homunculus Nebula, and which delineates very well the innermost contours of the red- and blueshifted lobes likely due to limb brightening. The inner contour of the redshifted emission was proposed to be a disrupted torus, but here we reveal that it is at least part of the molecular emission originating from the lobes and/or the expanding equatorial skirt. On the other hand, closer to systemic velocities (±100 km s-1), the CO molecular gas traces an inner butterfly-shaped structure that is also revealed at near-IR and mid-IR wavelengths as the region in which the shielded dust resides. The location and kinematics of the molecular component indicate that this material has formed after the different eruptions of n Carinae.Fil: Zapata, Luis A.. Universidad Nacional Autónoma de México; MéxicoFil: Loinard, Laurent. Universidad Nacional Autónoma de México; MéxicoFil: Fernandez Lopez, Manuel. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Toalá, Jesús A.. Universidad Nacional Autónoma de México; MéxicoFil: González, Ricardo F.. Universidad Nacional Autónoma de México; MéxicoFil: Rodríguez, Luis F.. Universidad Nacional Autónoma de México; MéxicoFil: Gull, Theodore R.. No especifíca;Fil: Morris, Patrick W.. No especifíca;Fil: Menten, Karl M.. Max Planck Institute For Radio Astronomy; AlemaniaFil: Kamiński, Tomasz. Nicolaus Copernicus Astronomical Center of the Polish Academy of Sciences; Poloni

    Breaking the Mode Degeneracy of Surface-Plasmon Resonances in a Triangular System

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    In this paper, we present a systematic investigation of symmetry-breaking in the plasmonic modes of triangular gold nanoprisms. Their geometrical C3 symmetry is one of the simplest possible that allows degeneracy in the particle's mode spectrum. It is reduced to the non-degenerate symmetries Cv or E by positioning additional, smaller gold nanoprisms in close proximity, either in a lateral or a vertical configuration. Corresponding to the lower symmetry of the system, its eigenmodes also feature lower symmetries (Cv), or preserve only the identity (E) as symmetry. We discuss how breaking the symmetry of the plasmonic system not only breaks the degeneracy of some lower order modes, but also how it alters the damping and eigenenergies of the observed Fano-type resonances

    Trypsin/α-amylase inhibitors and thionins: possible defence proteins from barley

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    This chapter reviews recent work on the trypsin/α-amylase inhibitor and thionin protein families. The genomic distribution of protein genes in barley and related species, gene expression and in vitro activities are considered. Some of the evidence of a possible defence role against stored products pests for inhibitors and thionins is briefly discusse

    Análisis comparativo de suelos cultivados y de monte de la provincia del Chaco, Argentina = Comparative analysis of cultivated and native forest soilsof the province of Chaco, Argentina

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    La agricultura en el norte argentino se ha intensificado últimamente avanzando sobre nuevas tierras, generando un impacto sobre los recursos naturales entre los que se encuentra el suelo. Se analizaron variables físicas, químicas y biológicas con el fin de dilucidar cuál de éstas muestra un mayor contraste. Se tomaron muestras de dos campos ubicados en la región oeste de la provincia del Chaco: uno con producción agrícola en un suelo desmontado hace 10 años, otro que realiza producción agrícola hace 80 años. En ambos se tomó el monte contiguo como situación testigo. El muestreo de los suelos se realizó en otoño de dos años consecutivos a una profundidad de cero a 10 y de 10 a 20 centímetros. Como variables físico-químicas y químicas se evaluaron pH, conductividad eléctrica, nitrógeno total, carbono orgánico, fósforo disponible, potasio, calcio, magnesio y sodio. Como variables físicas se determinaron densidad aparente y resistencia mecánica a la penetración. Y como variables biológicas se determinaron actividad respiratoria microbiana del suelo y cuantificación de glomalina fácilmente extraíble. Se realizó análisis de la varianza, test de Tukey (α = 0,05) arrojando diferencias estadísticamente significativas en la mayoría de las variables siendo positivos los valores de los suelos de monte. Además, se realizó un análisis de componentes principales. Las variables más determinantes fueron: densidad aparente, resistencia mecánica a la penetración, pH, el carbono orgánico y la glomalina fácilmente extraíble.Agriculture in northern Argentina has intensified lately, advancing on new lands, generating an impact on natural resources, including the soil. Physical, chemical and biological variables were analyzed in order to elucidate which of these shows the greatest contrast. Samples were taken from two fields: one with agricultural production on land cleared 10 years ago, another that has been producing agricultural production for the last 80 years. In both, the contiguous native vegetation was taken as control. Soil sampling was carried out in the fall of two consecutive years at a depth of zero to 10 and 10 to 20 centimeters. As physicochemical and chemical variables, pH, electrical conductivity, total nitrogen, organic carbon, available phosphorus, potassium, calcium, magnesium and sodium were evaluated. As physical variables, apparent density and mechanical resistance to penetration were determined. As biological variables, microbial respiratory activity of the soil and quantification of easily extractable glomalin were determined. Analysis of variance, Tukey’s test (α = 0.05) was performed, yielding statistically significant differences in most of the variables, being positive the values from the native vegetation soils. In addition, a principal component analysis was performed. The most determining variables were: apparent density, mechanical resistance to penetration, pH, organic carbon and easily extractable glomalin.EEA CorrientesFil: Pérez, Germán Luis. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto Agrotécnico; ArgentinaFil: Sotelo, Cristina Esther. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto Agrotécnico; ArgentinaFil: Sirio, Andrea A. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto Agrotécnico; ArgentinaFil: Carnicer, Sebastian. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto Agrotécnico; ArgentinaFil: Mansilla, Natalia P. Provincia del Chaco. Ministerio de Producción. Dirección de Suelos y Agua Rural; ArgentinaFil: Fernandez Lopez, Carolina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Corrientes; ArgentinaFil: Castelan, Maria E. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto Agrotécnico; Argentin
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