Sample records for COMETAS (comets)
from WorldWideScience.org

Sample records 1 - 20 shown. Select sample records:



1

El Ensayo Cometa: una técnica para evaluar genotoxicidad en el ADN de oocitos bovinos/ The Comet Assay: a technic to evaluate genotoxicity in DNA bovine oocytes

Rodrigo A, Urrego; Pareja, Andrés; Vásquez, Neil A; Márquez, María E
2005-09-01

Resumen en español La electroforesis en gel de células individuales o Ensayo Cometa, es frecuentemente usada para medir el daño en el ADN de las células. En la mayoría de estudios, los linfocitos de sangre periférica son utilizados como modelo celular. Sin embargo, en los últimos años, la aplicación de esta técnica se ha extendido a las células germinales, con el fin de evaluar la integridad del ADN espermático, las condiciones de estrés oxidativo en oocitos porcinos y en embrio (mas) nes bovinos; además, la muerte celular en embriones de ratón. Para la realización de la electroforesis de células individuales en un sistema como los oocitos bovinos se hace imprescindible superar dos grandes limitantes en la estructura complejo-cúmulo-oocito (CCOS): una, la degradación de las glicoproteínas de la zona pelúcida y dos, eliminar el nivel de compactación del genoma haploide bovino en metafase II. Dichas limitantes no permiten una migración adecuada del ADN dentro del gel de agarosa. En este estudio se demuestra que el uso de una solución de lisis con proteinasa K durante 3 h y 10 min de corrido electroforético, permite obtener cometas cuantificables de oocitos bovinos madurados in vitro que pueden ser utilizados en estudios genotóxicos en este sistema celular. Resumen en inglés The single cell gel electrophoresis or the comet assay is used to measure the DNA damage of individual cells, for most studies the lymphocytes from peripheral blood are used as cellular model. However, during the last years, the application of this technique has been extended to the germinal cells with the purpose of evaluating the integrity of the spermatic DNA, oxidative stress conditions in boar oocytes and bovine embryos besides cellular death in mouse embryos. Applyi (mas) ng the comet assay to a system such as the bovine oocytes it becomes indispensable to overcome two big structural barriers in the cumulus-oocyte-complex (COC): first, the degradation of the glycoproteins in the zona pellucida and second, the elimination of the flatten level of the haploid metaphase II bovine oocyte genome. These obstacles do not allow an appropriate migration of the DNA through the agarose gel. In this study it is demonstrated that the use of a lysis solution with proteinase K during 3 h and 10 min in electrophoretic running allows to obtain quantifiable comets of bovine oocytes matured in vitro, which can be used in genotoxic studies.

Scientific Electronic Library Online (Spanish)

2

Búsqueda general con la cámara mosaico CCD del telescopio Schmidt de 1m del Observatorio Nacional de Venezuela

Ferrín, I; Leal, C; Hernández, J
2006-05-01

Resumen en español En el presente trabajo se muestran los resultados del programa de búsqueda y seguimiento de diversos objetos astronómicos: estrellas variables, supernovas y objetos en movimiento dentro del Sistema Solar. Para ello estamos utilizando el telescopio Schmidt de 1m de diámetro del Observatorio Nacional de Venezuela, el cual tiene acoplado una cámara mosaico CCD de 67 Megapíxeles, en un arreglo de 4 x 4 CCDs, cada uno de 2048 x 2048 píxeles. Hasta la presente hemos detec (mas) tado 372 nuevas estrellas variables, una de las cuales fue identificada como una radiofuente, y el resto son muy probablemente estrellas ráfagas de muy corto periodo. Dentro del Sistema Solar hemos encontrado TNOs (Trans-neptunianos), NEOs (Near-Earths-Objects), cometas y asteroides del cinturón principal. Se diseñó un programa de búsqueda automática para optimizar el procesamiento de los datos. La cámara ya ha demostrado sus grandes posibilidades de observación, siendo sus descubrimientos más representativos 12 nuevos asteroides, 372 estrellas variables y el TNO 38628 Huya. Resumen en inglés In the present work we report the result of our search and follow up program of several types of astronomical objects: variable stars, supernovas, and moving objects inside the solar system. We used the 1 m Schmidt telescope of the National Observatory of Venezuela which has attached a Mosaic CCD Camera of 67 Megapixels, in an array of 4 x 4 CCDs, each of 2048 x 2048 pixels. Up to now we have detected 372 variable stars, one of which has been identified as a radio source, (mas) and the rest are very probably flare stars of very short period. Inside the solar system we have found TNOs (trans-neptunian objects), NEAs (near earth asteroids), comets and asteroids of the main belt. We have written a software program to detect authomatically moving objects, to optimize the data processing. The camera has demonstrated its great observational possibilities, being its most representative discoveries 12 new asteroids, 372 variblestars, and the TNO 38628 Huya.

Scientific Electronic Library Online (Spanish)

3

Evaluación del daño en el ADN y vigilancia biológica de la exposición laboral a solventes orgánicos, 2006/ DNA damage assessment and biological monitoring of occupational exposure to organic solvents, 2006

Torres, Carlos Humberto; Varona, Marcela E.; Lancheros, Angélica; Patiño, Rosa Isabel; Groot, Helena
2008-03-01

Resumen en español Introducción. La exposición a solventes es uno de los mayores riesgos potenciales para millones de trabajadores en el mundo; los solventes generan contaminación ambiental y desencadenan problemas de salud pública. Objetivo. Determinar los niveles de los metabolitos benceno, tolueno y xileno, los polimorfismos de las enzimas CYP2E1, GSTM1, GSTT1 y el daño del ADN mediante el ensayo del cometa. Materiales y métodos. Se llevó a cabo un estudio descriptivo de corte tra (mas) nsversal para la determinación de polimorfismos genéticos y prueba del cometa en 90 trabajadores pertenecientes a cinco empresas. Se aplicó una encuesta, se tomaron muestras de sangre y de orina, se midieron las concentraciones de fenol, ácido hipúrico orto y meta-metilhipúrico. Se hizo el análisis estadístico y se exploraron posibles asociaciones. Resultados. El 34,4% eran trabajadores con exposición directa a solventes. En este grupo se evidenciaron concentraciones superiores a los límites permisibles en 3,3% para fenol, en 6,6% para ácido hipúrico, en 3,3% para ácido orto-metilhipúrico y en 36,7% para ácido meta-metilhipúrico, mayor longitud promedio de la cola del cometa (19,5 µm) y un incremento del porcentaje de células con daño medio (19,0%) (p=0,0007). El porcentaje de individuos expuestos con genotipos ausentes para las enzimas GSTT1 y GSTM1 fue de 46,7% y de 56,8%, respectivamente. Conclusión. El uso de biomarcadores de exposición, efecto y susceptibilidad, se ha convertido en una herramienta fundamental para la evaluación del riesgo asociado con la exposición a agentes tóxicos. Resumen en inglés Introduction. Exposure to solvents is one of the highest potential risks for millions of workers in the world; they can generate substantial environmental pollution leading to outbreaks of public health problems. Objective. Blood levels were determined for metabolites of benzene, toluene and xylene, and polymorphisms for enzymes CYP2E1, GSTM1, GSTT1 were characterized. Damage to DNA was assessed by the comet assay for exposure to organic solvents. Materials and methods. A (mas) cross-sectional study was undertaken in 90 employees from 5 different companies. A survey form was administered; blood was sampled to detect the genetic polymorphisms and to apply the comet assay (single cell gel electrophoresis) to detect DNA fragmentation. The concentrations of phenol, ortho and meta methylhippuric acids were measured in urine. Statistical analyses explored the possible associations. Results. The percentage of workers directly exposed to solvents was 34.4%. In this group, the evidence indicated concentrations higher than the permitted limits: 3.3% for phenol, 6.6% for hippuric acid, 3.3% for ortho-methylhippuric acid and 36.7% for metamethylhippuric acid. In the Comet assay, the length of the comet’s tail was greater than average (19.5 ìm) in exposed subjects, and the percentage of cells with mild damage (19.0%) (p=0.0007) was higher. The percentage of exposed individuals with absent genotypes for enzymes GSTT1 and GSTM1 was 46.7% and 56.8% respectively. Conclusion. Exposure biomarkers have become fundamental tools for the evaluation of risk associated with exposure to toxic agents

Scientific Electronic Library Online (Spanish)

4

Warm water vapour in the sooty outflow from a luminous carbon star

Decin, L.; Agúndez, Marcelino; Barlow, Michael J.; Daniel, F.; Cernicharo, José; Lombaert, J. R.; Beck, E. de; Royer, P.; Vandenbussche, B.; Wesson, R.; Polehampton, E. T.; Blommaert, J. A. D. L.; Meester, W. de; Exter, K.; Feuchtgruber, H.; Gear, W. K.; Gomez, H. L.; Groenewegen, M. A. T.; Guélin, M.; Hargrave, P. C.; Huygen, R.; Imhof, P.; Ivison, R. J.; Jean, C.; Kahane, C.; Kerschbaum, F.; Leeks, S. J.; Lim, T.; Matsuura, M.; Olofsson, G.; Posch, T.; Regibo, S.; Savini, G.; Sibthorpe, B.; Swinyard, B. M.; Yates, J. A.; Waelkens, C.
2010-09-02

Digital.CSIC (Spain)

5

Trapping and adsorption of CO2 in amorphous ice: A FTIR study

Gálvez, Óscar; Maté, Belén; Herrero, Víctor J.; Escribano, Rafael

7 pages, 4 figures.-- Printed version published on Oct 2008. | The interaction of carbon dioxide and amorphous water ice at 95 K is studied using transmission infrared spectroscopy. Samples are prepared in two ways: co-deposition of the gases admitted simultaneously or sequential deposition, in whic...

DRIVER (Spanish)

6

Trapping and adsorption of CO2 in amorphous ice: A FTIR study

Gálvez, Óscar; Maté, Belén; Herrero, Víctor J.; Escribano, Rafael
2008-06-06

Digital.CSIC (Spain)

7

The outburst of the κ Cygnids in 2007: clues about the catastrophic break up of a comet to produce an Earth-crossing meteoroid stream

Trigo-Rodríguez, Josep Maria; Madiedo, José M.; Williams, Iwan P.; Castro-Tirado, Alberto J.

9 pages, 3 figures.-- Published online Nov 25, 2008. | Using high-resolution, low-scan-rate, all-sky CCD cameras and high-level CCD video cameras, the Spanish Meteor and fireball Network (SPMN) recorded the 2007 κ Cygnid fireball outburst from several observing stations. Here, accurate trajectory, r...

DRIVER (Spanish)

8

The outburst of the κ Cygnids in 2007: clues about the catastrophic break up of a comet to produce an Earth-crossing meteoroid stream

Trigo-Rodríguez, Josep Maria; Madiedo, José M.; Williams, Iwan P.; Castro-Tirado, Alberto J.
2009-01-01

Digital.CSIC (Spain)

9

The gas and dust coma of Comet C/1999 H1 (Lee)

Lara, Luisa María; Rodrigo Montero, Rafael; Tozzi, G.P.; Boehnhardt, H.; Leisy, P.

The final version is available at: http://www.aanda.org | Comet Lee (C/1999 H1) was observed on June 6, 1999 when it was at rh = 0.98 AU and Δ = 1.195 AU. The spectrophotometric observations, between 0.6 and 1 μm, were aimed at the detection of the CI(1D) doublet λλ 9823/9850 Å. The non-detection of...

DRIVER (Spanish)

10

The gas and dust coma of Comet C/1999 H1 (Lee)

Lara, Luisa María; Rodrigo Montero, Rafael; Tozzi, G.P.; Boehnhardt, H.; Leisy, P.
2004-01-01

Digital.CSIC (Spain)

11
12

Stardust's Hydrazine (N2H4) Fuel: A Potential Contaminant for the Formation of Titanium Nitride (Osbornite)

Martínez-Frías, Jesús; Nna Mvondo, Delphine; Rodríguez-Losada, José A.
2007-03-14

Digital.CSIC (Spain)

13

Selection against spermatozoa with fragmented DNA after postovulatory mating depends on the type of damage

Hourcade, Juan D.; Pérez-Crespo, Miriam; Fernández González, Raúl; Pintado, Belén; Gutiérrez-Adán, Alfonso
2010-01-31

Digital.CSIC (Spain)

14

Physics and chemistry of icy particles in the universe: answers from microgravity.

Ehrenfreund, P.; Fraser, H. J.; Blum, J.; Cartwright, Julyan H. E.; García-Ruiz, J. M.; Hadamcik, E.; Levasseur-Regourd, A. C.; Price, S.; Prodi, F.; Sarkissian, A.
2003-07-01

Digital.CSIC (Spain)

16

Outburst activity in comets-II. A multiband photometric monitoring of comet 29P/Schwassmann-Wachmann 1

Trigo-Rodríguez, J. M.; García-Hernández, D. A.; Sánchez, A.; Lacruz, J.; Davidsson, B. J. R.; Rodríguez, D.; Pastor, S.; Reyes, J. A. de los
2010-01-01

Digital.CSIC (Spain)

17

Observations of a very bright fireball and its likely link with comet C/1919 Q2 Metcalf

Trigo-Rodríguez, Josep Maria; Madiedo, José M.; Williams, Iwan P.; Castro-Tirado, Alberto J.; Llorca, Jordi

8 pages, 3 figures, 4 tables.-- Article in press. | A very bright fireball called Béjar (SPMN110708), with a maximum brightness of −18, was observed over much of Spain as well as parts of Portugal and France on 2008 July 11 at 21:17:39 utc. Fortuitously, it flew over many of the instruments that are...

DRIVER (Spanish)

18

Observations of a very bright fireball and its likely link with comet C/1919 Q2 Metcalf

Trigo-Rodríguez, Josep Maria; Madiedo, José M.; Williams, Iwan P.; Castro-Tirado, Alberto J.; Llorca, Jordi; Vítek, Stanislav; Jelínek, Martin
2009-02-11

Digital.CSIC (Spain)

19

Observations of Comet 9P/Tempel 1 around the Deep Impact event by the OSIRIS cameras onboard Rosetta

Keller, H. U.; Küppers, Michael; Fornasier, Sonia; Gutiérrez, Pedro J.; Hviid, Stubbe F.; Jorda, Laurent

17 pp.-- Final full-text version of the paper available at: http://dx.doi.org/10.1016/j.icarus.2006.09.023. | The OSIRIS cameras on the Rosetta spacecraft observed Comet 9P/Tempel 1 from 5 days before to 10 days after it was hit by the Deep Impact projectile. The Narrow Angle Camera (NAC) monitored ...

DRIVER (Spanish)

20

Observations of Comet 9P/Tempel 1 around the Deep Impact event by the OSIRIS cameras onboard Rosetta

Keller, H. U.; Küppers, M.; Fornasier, S.; Gutiérrez, Pedro J.; Hviid, Stubbe F.; Jorda, L.; Knollenberg, Jörg; Lowry, Stephen C.; Rengel, Miriam; Bertini, Ivano; Cremonese, Gabriele; Wing, Ip; Koschny, Detlef; Kramm, Rainer; Kührt, E.; Lara, Luisa María; Sierks, Holger; Thomas, Nicolas; Barbieri, Cesare; Lamy, P.; Rickman, Hans; Rodrigo Montero, Rafael; A’Hearn, Michael F.; Angrilli, Francesco; Barucci, M. A.; Bertaux, Jean-Loup; Deppo, Vania da; Davidsson, B.; Cecco, Mariolino de; Debei, Stefano; Fulle, M.; Gliem, Fritz; Groussin, O.; López-Moreno, José Juan; Marzari, Francesco; Naletto, Giampiero; Sabau-Graziati, L.; Sanz Andrés, Ángel; Wenzel, Klaus-Peter
2007-03-01

Digital.CSIC (Spain)

21

Modeling of the Terminal Velocities of the Dust Ejected Material by the Impact

Rengel, Miriam; Küppers, M.; Keller, H. U.; Gutiérrez, Pedro J.
2007-01-03

Digital.CSIC (Spain)

23

Mechanism controller system for the optical spectroscopic and infrared remote imaging system instrument on board the Rosetta space mission

Rodrigo Montero, Rafael; Castro Marín, J. M.; Brown, V. J. G.; López Jiménez, A. C.; Rodríguez Gómez, J.
2001-02-22

Digital.CSIC (Spain)

24

Long-term simulations of the rotational state of small irregular cometary nuclei

Gutiérrez, Pedro J.; Jorda, L.; Ortiz, J. L.; Rodrigo Montero, Rafael

The final version is available at: http://www.aanda.org | We have performed simulations of the long-term evolution of the spin state of small active comet nuclei (1 km and 0.6 km) in the orbit of 46P/Wirtanen under the effect of the torque of the nongravitational force. A total of 46 combinationsof...

DRIVER (Spanish)

25

Long-term simulations of the rotational state of small irregular cometary nuclei

Gutiérrez, Pedro J.; Jorda, L.; Ortiz, J. L.; Rodrigo Montero, Rafael
2003-05-01

Digital.CSIC (Spain)

28

HCN spectroscopy of comet 73P/Schwassmann-Wachmann 3. A study of gas evolution and its link to CN

Paganini, Lucas; Villanueva, Gerónimo; Lara, Luisa-Maria; Lin, Zhong-Yi; Küppers, Michael; Hartogh, Paul; Fauré, André
2010-01-01

Digital.CSIC (Spain)

29

Genotoxic effects in swimmers exposed to disinfection by-products in indoor swimming pools

Kogevinas, Manolis; Villanueva, Cristina M.; Font-Ribera, Laia; Liviac, Danae; Bustamante, Mariona; Espinoza, Felicidad; Nieuwenhuijsen, Mark J.; Espinosa, Aina; Fernández, Pilar; DeMarini, David M.; Grimalt, Joan O.; Grummt, Tamara; Marcos, Ricard
2010-09-12

Digital.CSIC (Spain)

30

Erratum: Chemical abundances determined from meteor spectra – II. Evidence for enlarged sodium abundances in meteoroids

Trigo-Rodríguez, Josep Maria; Llorca, Jordi; Fabregat, Juan

1 page.-- Original paper available at: http://digital.csic.es/handle/10261/10750 | The paper ‘Chemical abundances determined from meteor spectra – II. Evidence for enlarged sodium abundances in meteoroids’was published in Mon. Not. R. Astron. Soc. 348, 802–810 (2004). Due to an omission, four refer...

DRIVER (Spanish)

32

Effects of irregular shape and topography in the thermophysical models of heterogeneous cometary nuclei

Gutiérrez, Pedro J.; Ortiz, J. L.; Rodrigo Montero, Rafael; López-Moreno, J. J.

The final version of the paper is available at: http://dx.doi.org/10.1051/0004-6361:20010742 | Several improvements in the thermophysical model by Gutierrez et al. (2000) have been included in a new code to specifcally deal with fully irregular cometary nuclei. Also, the new code allows for the incl...

DRIVER (Spanish)

33

Effects of irregular shape and topography in the thermophysical models of heterogeneous cometary nuclei

Gutiérrez, Pedro J.; Ortiz, J. L.; Rodrigo Montero, Rafael; López-Moreno, José Juan
2001-05-21

Digital.CSIC (Spain)

34

E-Type Asteroid (2867) Steins as Imaged by OSIRIS on Board Rosetta

Keller, H. U.; Barbieri, Cesare; Koschny, Detlef; Lamy, P.; Rickman, Hans; Rodrigo Montero, Rafael; Sierks, Holger; A’Hearn, Michael F.; Angrilli, Francesco; Barucci, M. A.; Bertaux, Jean-Loup; Cremonese, Gabriele; Da Deppo, V.; Davidsson, B.; De Cecco, M.; Debei, Stefano; Fornasier, S.; Fulle, M.; Groussin, O.; Gutiérrez, Pedro J.; Hviid, Stubbe F.; Ip, W.; Jorda, L.; Knollenberg, Jörg; Kramm, Rainer; Kührt, E.; Küppers, M.; Lara, Luisa María; Lazzarin, M.; López-Moreno, José Juan; Marzari, Francesco; Michalik, H.; Naletto, Giampiero; Sabau-Graziati, L.; Thomas, Nicolas; Wenzel, K. P.; Bertini, Ivano; Besse, S.; Ferri, F.; Kaasalainen, M.; Lowry, Stephen C.; Marchi, S.; Mottola, S.; Sabolo, Walter; Schröder, S. E.; Spjuth, S.; Vernazza, P.
2010-01-01

Digital.CSIC (Spain)

35

Cosac, the cometary sampling and composition experiment on philae

Goesmann, Fred; Rosenbauer, Helmut; Roll, Reinhard; Szopa, Cyril; Raulin, François; Sternberg, Robert; Guy, Israel; Meierhenrich, Uwe; Thiemann, Wolfram; Muñoz Caro, Guillermo M.
2007-02-01

Digital.CSIC (Spain)

36

Coma Structures in Comet 73P/Schwassmann-Wachmann 3, Components B and C, Between January and May 2006

Vincent, Jean-Baptiste; Hermann, Bo¨hnhardt; Bo¨hnhardt, Hermann; Bertini, Ivano; Lara, Luisa-Maria; Ku¨ppers, Michael; Rodrigo, Rafael
2009-10-25

Digital.CSIC (Spain)

37

Chemical abundances determined from meteor spectra II. Evidence for enlarged sodium abundances in meteoroids

Trigo-Rodríguez, Josep Maria; Llorca, Jordi; Fabregat, Juan

9 pages, 5 figures.-- Printed version published Mar 2004. | Erratum (extra references) available at: http://digital.csic.es/handle/10261/10752 | The relative abundances of sodium in meteoroids have been estimated by averaging the composition of the radiating gas along the fireball path produced duri...

DRIVER (Spanish)

39

An investigation of errors in estimates of the cometary nuclei active area fractions

Gutiérrez, Pedro J.; Rodrigo Montero, Rafael; Ortiz, J.L.; Davidsson, B.J.R.

The final version is available at: http://www.aanda.org | Active area fractions of cometary nuclei are often estimated by comparing the observed water production rates with theoretical rates obtained by applying the fast rotator or subsolar point approximations to spherical model nuclei. Any discrep...

DRIVER (Spanish)

40

An investigation of errors in estimates of the cometary nuclei active area fractions

Gutiérrez, Pedro J.; Rodrigo Montero, Rafael; Ortiz, J. L.; Davidsson, B.
2003-01-01

Digital.CSIC (Spain)

41

A study of water production and temperatures of rotating irregularly shaped cometary nuclei.

Gutiérrez, Pedro J.; Ortiz, J. L.; Rodrigo Montero, Rafael; López-Moreno, J. J.

Calculations of water production rates and temperatures for rotating irregularly shaped bodies with and without topography are presented. These calculations are compared with the case of a spherical nucleus. For any combination of orbital parameters, rotation axis orientation, spin period, and physi...

DRIVER (Spanish)

42

A study of water production and temperatures of rotating irregularly shaped cometary nuclei.

Gutiérrez, Pedro J.; Ortiz, J. L.; Rodrigo Montero, Rafael; López-Moreno, José Juan
2000-01-21

Digital.CSIC (Spain)

43

A numerical model of cometary dust structures

Vincent, Jean-Baptiste; Böhnhardt, Hermann; Lara, Luisa-Maria
2010-01-01

Digital.CSIC (Spain)

44

A meteorite-dropping superbolide from the catastrophically disrupted comet C1919Q2 Metcalf: a pathway for meteorites from Jupiter family comets

Trigo-Rodríguez, Josep Maria; Madiedo, José M.; Williams, Iwan P.; Castro-Tirado, Alberto J.; LLorca, Jordi

2 pages, 1 figure.-- Contributed to: 40th Lunar and Planetary Science Conference (The Woodlands, Texas ,Mar 23-27, 2009). | It is widely accepted that cometary nucleiare composed of a mix of volatile ices and meteoritic materials. In a series of seminal papers F. L. Whipple tried to explain how the...

DRIVER (Spanish)

45

A meteorite-dropping superbolide from the catastrophically disrupted comet C1919Q2 Metcalf: a pathway for meteorites from Jupiter family comets

Trigo-Rodríguez, Josep Maria; Madiedo, José M.; Williams, Iwan P.; Castro-Tirado, Alberto J.; Llorca, Jordi; Vitek, Stanislav; Jelínek, Martin
2009-03-01

Digital.CSIC (Spain)