Mid-J CO emission from the Orion BN/KL explosive outflow

High spatial resolution low-J 12CO observations have shown that the wide-angle outflow seen in the Orion BN/KL region correlates with the famous H2 fingers. Recently, high-resolution large-scale mappings of mid- and higher-J CO emissions have been reported toward the Orion molecular cloud 1 core region using the APEX telescope. Therefore, it is of interest to investigate this outflow in the higher-J 12CO emission, which is likely excited by shocks. The observations were carried out using the dual-color heterodyne array CHAMP+ on the APEX telescope. The images of the Orion BN/KL region were obtained in the 12CO J=6-5 and J=7-6 transitions with angular resolutions of 8.6 and 7.4 arcsec, respectively. The results show a good agreement between our higher-J 12CO emission and SMA low-J 12CO data, which indicates that this wide-angle outflow in Orion BN/KL is likely the result of an explosive event that is related to the runaway objects from a dynamically decayed multiple system. From our observations, we estimate that the kinetic energy of this explosive outflow is about 1-2x10^47 erg. In addition, a scenario has been proposed where part of the outflow is decelerated and absorbed in the cloud to explain the lack of CO bullets in the southern part of BN/KL, which in turn induces the methanol masers seen in this region.Comment: 5 pages, 4 figure

Tracing the Bipolar Outflow from Orion Source I

Using CARMA, we imaged the 87 GHz SiO v=0 J=2-1 line toward Orion-KL with 0.45 arcsec angular resolution. The maps indicate that radio source I drives a bipolar outflow into the surrounding molecular cloud along a NE--SW axis, in agreement with the model of Greenhill et al. (2004). The extended high velocity outflow from Orion-KL appears to be a continuation of this compact outflow. High velocity gas extends farthest along a NW--SE axis, suggesting that the outflow direction changes on time scales of a few hundred years.Comment: 4 pages, 4 figures; accepted for publication in Ap J Letter

Robustness of dynamically gradient multivalued dynamical systems

In this paper we study the robustness of dynamically gradient multivalued semiflows. As an application, we describe the dynamical properties of a family of Chafee-Infante problems approximating a differential inclusion studied in J. M. Arrieta, A. Rodríguez-Bernal and J. Valero, Dynamics of a reaction-diffusion equation with a discontinuous nonlinearity, International Journal of Bifurcation and Chaos, 16 (2006), 2965-2984, proving that the weak solutions of these problems generate a dynamically gradient multivalued semiflow with respect to suitable Morse sets.Ministerio de Educación, Cultura y DeporteMinisterio de Economía y CompetitividadJunta de AndalucíaFundação de Amparo à Pesquisa do Estado de São PauloConselho Nacional de Desenvolvimento Científico e Tecnológic

Have proto-planetary discs formed planets?

It has recently been noted that many discs around T Tauri stars appear to comprise only a few Jupiter-masses of gas and dust. Using millimetre surveys of discs within six local star-formation regions, we confirm this result, and find that only a few percent of young stars have enough circumstellar material to build gas giant planets, in standard core accretion models. Since the frequency of observed exo-planets is greater than this, there is a `missing mass' problem. As alternatives to simply adjusting the conversion of dust-flux to disc mass, we investigate three other classes of solution. Migration of planets could hypothetically sweep up the disc mass reservoir more efficiently, but trends in multi-planet systems do not support such a model, and theoretical models suggest that the gas accretion timescale is too short for migration to sweep the disc. Enhanced inner-disc mass reservoirs are possible, agreeing with predictions of disc evolution through self-gravity, but not adding to millimetre dust-flux as the inner disc is optically thick. Finally, the incidence of massive discs is shown to be higher at the {\it proto}stellar stages, Classes 0 and I, where discs substantial enough to form planets via core accretion are abundant enough to match the frequency of exo-planets. Gravitational instability may also operate in the Class 0 epoch, where half the objects have potentially unstable discs of \ga30 % of the stellar mass. However, recent calculations indicate that forming gas giants inside 50 AU by instability is unlikely, even in such massive discs. Overall, the results presented suggest that the canonically 'proto-planetary' discs of Class II T Tauri stars {\bf have globally low masses in dust observable at millimetre wavelengths, and conversion to larger bodies (anywhere from small rocks up to planetary cores) must already have occurred.}Comment: Accepted for publication in MNRAS (main journal

Effect of pH, temperature ,conductivity and sediment size on thorium activities along Jucar River (Spain)

[EN] A study is presented on the distribution of thorium and radium isotopes in sediments, suspended matter and water collected along Jucar river (East of Spain), using low-level alpha-spectrometry. The first aim of this work is to study the thorium and radium activity in water, sediment and suspended matter and their dependence on pH, temperature, conductivity and sediment sizes along Jucar river. The analysis of activity variation with these parameters will provide information about the dynamics of these radionuclides in rivers. The values obtained for the distribution factors between suspended matter and water (K-d) are also discussed.Sanchez, F.; Rodríguez-Álvarez, M. (1999). Effect of pH, temperature ,conductivity and sediment size on thorium activities along Jucar River (Spain). Journal of Radioanalytical and Nuclear Chemistry. 242(3):671-681. doi:10.1007/BF02347378S6716812423M. J. Rodríguez-Alvarez, F. Sánchez, J. Radioanal. Nucl. Chem., 191 (1995) 3.M. J. Rodríguez-Alvarez, F. Sánchez, E. Navarro, Proc. 3rd Intern. Summer School, Huelva Spain,M. García-León andG. Madurga (Eds), World Scientific, Singapore, 1994, p. 549.M. J. Rodríguez-Alvarez, Medidas de Uranio, Torio y Radio en Muestras Ambientales por Espectrometría alfa. Aplicación a un Modelo Unidimensional de Transporte de Radionúclidos en el Río Júcar. PhD Thesis, Universidad de Valencia, Spain, 1998 (in Spanish).M. J. Rodríguez-Alvarez, F. Sánchez, J. Radioanal. Nucl. Chem., to be published.M. J. Rodríguez-Alvarez, F. Sánchez, J. Radioanal. Nucl. Chem., 190 (1995) 113.Uranium Disequilibrium Series. Applications to Environmental Problems,M. Ivanovich andR. S. Harmon (Eds), Clarendon Press, Oxford, 1992.A. Martinez-Aguirre, M. García-León, J. Radioanal. Nucl. Chem., 155 (1991) 97.R. Periañez, A. Martinez-Aguirre, J. Environ. Radiact., 35 (1997) No. 3, 281.P. Beneš, P. Picat, M. Černík, J. M. Quinault, J. Radioanal. Nucl. Chem., 159 (1992) 175.P. Beneš, M. Černík, J. Radioanal. Nucl. Chem., 159 (1992) 187.N. A. Talvitie, Anal. Chem., 44 (1972) 280.R. García-Tenorio, M. García-León, M. Madurga, C. Piazza, Anal. Física B, 82 (1986) 238.L. Hallstadius, Nucl. Instrum. Meth. Phys. Res. 223 (1984) 266.G. J. Hancock, P. Martin, Appl. Radiation Isotopes, 40 (1989) 63.USEPA, Potential Health and Environmental Hazard of Uranium Mine Wastes, EPA 520/1-83-007, U.S. Environmental Protection Agency, Washington, 1983.P. Beneš, Physico-chemical Forms and Migration in Continental Waters of Radium from Uranium Mining and Milling, in: Environmental Migration of Long-lived Radionuclides, IAEA, Vienna, 1982, p. 3.F. Šebesta, Environ. Sci. Technol., 15 (1981) 71.P. Beneš, Water Res., 17 (1983) 619.P. Beneš, P. Strejc, J. Radioanal. Nucl. Chem., 99 (1986) 407.T. H. Sibley, C. Myttenaere, Application of Distribution Coefficients to Radiological Assesment Models, Elsevier Applied Science Publishers, 1986.J. E. Till, H. R. Meyer, Radiological Assessment. A Textbook on Environmental Dose Analysis, NUREG/CR-3332, Washington, D.C., 1983.Sedimentk d and Concentration Factors for Radionuclides in Marine Environment, IAEA Technical Report Series, No. 247, 1985

ALMA observations of the outflow from the Source I in the Orion-KL region

In this {\it Letter}, we present sensitive millimeter SiO (J=5-4; $\nu$=0) line observations of the outflow arising from the enigmatic object Orion Source I made with the Atacama Large Millimeter/Submillimeter Array (ALMA). The observations reveal that at scales of a few thousand AU, the outflow has a marked "butterfly" morphology along a northeast-southwest axis. However, contrary to what is found in the SiO and H$_2$O maser observations at scales of tens of AU, the blueshifted radial velocities of the moving gas are found to the northwest, while the redshifted velocities are in the southeast. The ALMA observations are complemented with SiO (J=8-7; $\nu$=0) maps (with a similar spatial resolution) obtained with the Submillimeter Array (SMA). These observations also show a similar morphology and velocity structure in this outflow. We discuss some possibilities to explain these differences at small and large scales across the flow.Comment: Accepted to ApJ

Invariants of complex structures on nilmanifolds

Fil: Rodríguez Valencia, Edwin Alejandro. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Rodríguez Valencia, Edwin Alejandro. Universidad Nacional de Córdoba. Centro de Investigación y Estudios de Matemática; Argentina.Fil: Rodríguez Valencia, Edwin Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigación y Estudios de Matemática; Argentina.Let (N, J) be a simply connected 2n-dimensional nilpotent Lie group endowed with an invariant complex structure. We define a left invariant Riemannian metric on N compatible with J to be minimal, if it minimizes the norm of the invariant part of the Ricci tensor among all compatible metrics with the same scalar curvature. In [7], J. Lauret proved that minimal metrics (if any) are unique up to isometry and scaling. This uniqueness allows us to distinguish two complex structures with Riemannian data, giving rise to a great deal of invariants. We show how to use a Riemannian invariant: the eigenvalues of the Ricci operator, polynomial invariants and discrete invariants to give an alternative proof of the pairwise non-isomorphism between the structures which have appeared in the classification of abelian complex structures on 6-dimensional nilpotent Lie algebras given in [1]. We also present some continuous families in dimension 8.publishedVersionFil: Rodríguez Valencia, Edwin Alejandro. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Rodríguez Valencia, Edwin Alejandro. Universidad Nacional de Córdoba. Centro de Investigación y Estudios de Matemática; Argentina.Fil: Rodríguez Valencia, Edwin Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigación y Estudios de Matemática; Argentina.Matemática Pur

Ressenyes

Index de les obres ressenyades: VÁZQUEZ VARELA, J. M. ; RODRÍGUEZ COLMENERO, A. Galicia, Art

Predicting healthcare cost of diabetes using machine learning models

González-Rodríguez, J.; Díaz Carnicero, J.; Vivas-Consuelo, D.; González-De Julián, S.; Pinzón Espitia, OL. (2019). Predicting healthcare cost of diabetes using machine learning models. R. Company, J. C. Cortés, L. Jódar and E. López-Navarro. 99-104. http://hdl.handle.net/10251/180540S9910

The fluid mechanics of bubbly drinks

Bubbly drinks are surprisingly attractive. There is something about the nature of the these beverages that make them preferable among other choices. In this article we explore the physics involved in this particular kind of two-phase, mass-transfer-driven flows.Comment: Extended version of Zenit R and Rodr\'iguez-Rodr\'iguez J. The fluid mechanics of bubbly drinks. Physics Today, Vol. 71(11) pp. 44-50, November 201