scholarly journals Neutron capture 128 Xe and 129 Xe in the San Juan mass of the Campo del Cielo IAB iron meteorite: Evidence for a high fluence of thermalized neutrons

Author(s):  
O. Pravdivtseva ◽  
M. E. Varela ◽  
A. Meshik ◽  
A. J. Campbell ◽  
M. Saavedra ◽  
...  

1965 ◽  
Vol 20 (4) ◽  
pp. 533-540 ◽  
Author(s):  
F. Begemann ◽  
E. Vilcsek

The 36Cl produced by spallation reactions and neutron capture on 35Cl has been measured separately in three stone meteorites and one iron meteorite.The spallation produced 36Cl activities - given in dpm per kg (Fe+Ni + 10 x Ca) -have been found to be (20.5 ±2) for Abee - Centre, (21.8 ±2) for Abee - Surface, (21.3 -26.2) for Leedey, and ≦ (22 ±10) for Norton County- Surface. They are in good agreement with those found in iron meteorites of comparable size and known terrestrial age.The neutron induced activities in the same samples are (0.21 ±0.2), (0.08 ± 0.17), (1.7 ±1), and ≦ (30 ± 15) dpm/100 mg Cl. In spite of the large uncertainties highly significant conclusions can be drawn from these data regarding the mass loss of the meteorites during approximately the last million years, either by space erosion or due to ablation during the passage through the terrestrial atmosphere. Based on calculations of EBERHARDT, GEISS, and LUTZ the ratio of post-atmospheric to pre-atmospheric radius derived for the three meteorites is Abee: rM/R=0.86 or rΜ/R > 0.7 on the 3 σ significance level, Leedey (meteorite shower): rM/R=0.5, and Norton County: rM/R=0.77 or rM/R > 0.63 (3 σ level).No neutron induced activity could be detected in the iron meteorite Cranbourne (Nr. 4). The total and spallation produced 36Cl of two adjacent samples - although differing in their Cl content by more than a factor of twenty-was the same within the experimental limits of error (4.7 ± 0.2) dpm/kg. The low value is attributed to a high terrestrial age and/or the size of this meteorite. 39Ar could not be detected (< 0.64 dpm/kg. 3 σ level).



2011 ◽  
Vol 75 (19) ◽  
pp. 5706-5715 ◽  
Author(s):  
Hiroshi Hidaka ◽  
Shigekazu Yoneda




Author(s):  
Antonio Villalobos-González ◽  
Mónica B. López-Hernández ◽  
Noel A. Valdivia-González ◽  
Enrique Arcocha-Gómez ◽  
Juan Medina-Méndez
Keyword(s):  
Zea Mays ◽  

El objetivo fue estudiar la variabilidad genética de características morfológicas de maíces nativos en la Península de Yucatán (PY), México. Se utilizaron trece accesiones de maíz nativo reconocidas con el nombre de Naál Xóy, Xnúc Naál Blanco, Gallito Amarillo, Dzit Bacal, Mejeén Naál, Rosa San Juan, Cháck-Chóp, Teél Cháck, Sáck Teél, San Pableño, Ejú-Criollo Morado, Xmején Naál Tsitbacal y Clavo Chiapaneco. Los materiales se establecieron en Junio de 2017 y 2018, en Poxyaxum, Campeche, México, (19° 41´58.4´´ N, 90° 21´03.6´´ W y 30 msnm) bajo un diseño de bloques completos al azar con tres repeticiones. Los resultados revelaron diferencias (P£0.05) en las variables morfológicas evaluadas: número de días a floración masculina (FM) y femenina (FF) presento una inestabilidad de 12 días a FM y FF, con Naál Xóy y Ejú-Criollo Morado, y 15 días a madurez fisiológica con Clavo Chiapaneco. Una diferenciación de 98 y 126 cm en altura de mazorca y planta con Eju-Criollo Morado; 6 y 1.1 cm en longitud y diámetro de mazorca con Xnúc Naál Blanco y Cháck-Chóp, y Gallito Amarillo. Una variación de 4 hileras con Teél Cháck y 17 granos por hilera con San Pableño; 11 y 74 gr en peso de 100 granos (Xmején Naál Tsitbacal, Rosa San Juan y San Pableño) y granos por mazorca (Naál Xóy); y una diferencia mayor en rendimiento con Naál Xóy y Dzit Bacal de 3105 kg.ha-1.



2004 ◽  
Vol 38 (12) ◽  
pp. 1176 ◽  
Author(s):  
Antonio Martín Araguz ◽  
Cristina Bustamante Martínez
Keyword(s):  


2020 ◽  
Vol 40 (3) ◽  
Author(s):  
Carolyn Jenkins ◽  
Melora E. Haas ◽  
Ashley Olson ◽  
Jennifer L. Ruesink
Keyword(s):  


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