Chronological and palaeoenvironmental context of human occupations at the Buendía rockshelter (Central Spain) during the late Upper Pleistocene in inland Iberia          下载免费PDF全文

IGNACIO DE LA TORRE  ROSA MARÍA ALBERT  ETHEL ALLUÉ  ESTEBAN ÁLVAREZ‐FERNÁNDEZ  M.TERESA APARICIO  ADRIÁN ARROYO  ALFONSO BENITO‐CALVO  MARÍA JOSÉ GIL GARCÍA  ELÍAS LÓPEZ‐ROMERO  NORAH MOLONEY  M. BLANCA RUIZ ZAPATA  PALMIRA SALADIÉ 《第四纪科学杂志》2015,30(4):376-390

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Impact Craters in South America,by Acevedo R. D., Rocca M. C. L., Ponce J. F., and Stinco S. G. Heidelberg: Springer, 2015. 104 p. SpringerBriefs in Earth Sciences: South America and the Southern Hemisphere. ISBN 978‐3‐319‐13092‐7.          下载免费PDF全文

Alvaro P. Crósta  Wolf Uwe Reimold 《Meteoritics & planetary science》2016,51(5):996-999

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ICE PATCH ORIGIN,EVOLUTION AND DYNAMICS IN A TEMPERATE HIGH MOUNTAIN ENVIRONMENT: THE JOU NEGRO,PICOS DE EUROPA (NW SPAIN)     

ENRIQUE SERRANO  JUAN J. GONZÁLEZ‐TRUEBA  JOSÉ J. SANJOSÉ  LUIS M. DEL RÍO 《Geografiska Annaler: Series A, Physical Geography》2011,93(2):57-70

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Shatter cones and planar deformation features confirm Santa Marta in Piauí State,Brazil, as an impact structure     

Grace Juliana Gonçalves de Oliveira  Marcos Alberto Rodrigues Vasconcelos  Alvaro Penteado Crósta  Wolf Uwe Reimold  Ana Maria Góes  Astrid Kowitz 《Meteoritics & planetary science》2014,49(10):1915-1928

A total of 184 confirmed impact structures are known on Earth to date, as registered by the Earth Impact Database . The discovery of new impact structures has progressed in recent years at a rather low rate of about two structures per year. Here, we introduce the discovery of the approximately 10 km diameter Santa Marta impact structure in Piauí State in northeastern Brazil. Santa Marta is a moderately sized complex crater structure, with a raised rim and an off‐center, approximately 3.2 km wide central elevated area interpreted to coincide with the central uplift of the impact structure. The Santa Marta structure was first recognized in remote sensing imagery and, later, by distinct gravity and magnetic anomalies. Here, we provide results obtained during the first detailed ground survey. The Bouguer anomaly map shows a transition from a positive to a negative anomaly within the structure along a NE–SW trend, which may be associated with the basement signature and in parts with the signature developed after the crater was formed. Macroscopic evidence for impact in the form of shatter cones has been found in situ at the base around the central elevated plateau, and also in the interior of fractured conglomerate boulders occurring on the floor of the surrounding annular basin. Planar deformation features (PDFs) are abundant in sandstones of the central elevated plateau and at scattered locations in the inner part of the ring syncline. Together, shatter cones and PDFs provide definitive shock evidence that confirms the impact origin of Santa Marta. Crystallographic orientations of PDFs occurring in multiple sets in quartz grains are indicative of peak shock pressures of 20–25 GPa in the rocks exposed at present in the interior of the crater. In contrast to recent studies that have used additional, and sometimes highly controversial, alleged shock recognition features, Santa Marta was identified based on well‐understood, traditional shock evidence.  相似文献   

Observations of the Oh Radio Lines of Comets at Nançay – Recent Developments     

Crovisier  Jacques  Colom  Pierre  Gérard  Éric  Bockelée-Morvan  Dominique 《Earth, Moon, and Planets》2002,90(1-4):369-370

The 18 cm lines of OH have been observed in more than 70 comets withthe Nançay radio telescope since 1974. The observations made from1982 to 1999 are now organized in a data base. The Nançay radiotelescope has been recently upgraded, and observations since 2000 aremade with a sensitivity increased by about a factor of two. Twelvecomets were observed from July 2000 to May 2002.  相似文献   

A study of the radial velocity of the star Θ1 Ori C     

É A. Vitrichenko 《Astronomy Letters》2002,28(5):324-334

The radial velocities of the star Θ¹ Ori C were measured from IUE spectra and are compared with published data. Two companions (C1 and C2) are assumed to be present. The probable periods for companion C1 can be estimated from the formula P=729.6/L days, where L<13 is an integer. Radialvelocity curves were constructed for L=11 and 12. The orbit turned out to be elliptical. At L=11, the orbital elements are P=66.3(1) days, γ=10.9(2) km s^?1, K=6.1(4) km s^?1, ω=?2.88(5) rad, e=0.43(6), and Ep=JD 2449044.7(4). The errors in the last decimal digit are given in parentheses. Companion C2 was as detected by temporal variations in the γ velocity of companion C1. Its orbit is assumed to be circular with the following elements: P=120(6) yr, γ=22(1) km s^?1, K=13(2) km s^?1, and Ep=1911(3) yr.  相似文献   

ANALYTICAL SOLUTIONS FOR CUSP RESONANCE IN DISSIPATIVE MHD     

ERDÉLYI  RÓBERT 《Solar physics》1997,171(1):49-59

The present paper considers resonant slow waves in 1D non-uniform magnetic flux tubes in dissipative MHD. Analytical solutions are obtained for the Lagrangian displacement and the Eulerian perturbation of the total pressure for both static and stationary equilibrium states. From these analytical solutions we obtain the fundamental conservation law and the jump conditions for resonant slow waves in dissipative MHD. The validity of the ideal conservation law and jump conditions obtained by Sakurai, Goossens, and Hollweg (1991) for static equilibria and Goossens, Hollweg, and Sakurai (1992) for stationary equilibria is justified in dissipative MHD.  相似文献   

CAN WE EXTRAPOLATE A MAGNETIC FIELD WHEN ITS TOPOLOGY IS COMPLEX?     

DÉmoulin  P.  HÉnoux  J. C.  Mandrini  C. H.  Priest  E. R. 《Solar physics》1997,174(1-2):73-89

In order to understand various solar phenomena controlled by the magnetic field, such as X-ray bright points, flares and prominence eruptions, the structure of the coronal magnetic field must be known. This requires a precise extrapolation of the photospheric magnetic field. Presently, only potential or linear force-free field approximations can be used easily. A more realistic modelling of the field is still an active research area because of well-known difficulties related to the nonlinear mixed elliptic-hyperbolic nature of the equations. An additional difficulty arises due to the complexity of the magnetic field structure which is caused by a discrete partition of the photospheric magnetic field. This complexity is not limited to magnetic regions having magnetic nulls (and so separatrices) but also occurs in those containing thin elongated volumes (called Quasi-Separatrix Layers) where the photospheric field-line linkage changes rapidly. There is a wide range for the thickness of such layers, which is determined by the character (bipolar or quadrupolar) of the magnetic region, by the sizes of the photospheric field concentrations and by the intensity of the electric currents. The aim of this paper is to analyse the recent nonlinear force-free field extrapolation techniques for complex coronal magnetic fields.  相似文献   

Direct-Drive Inertial Confinement Fusion Implosions on Omega     

S. P. Regan  T. C. Sangster  D. D. Meyerhofer  K. Anderson  R. Betti  T. R. Boehly  T. J. B. Collins  R. S. Craxton  J. A. Delettrez  R. Epstein  O. V. Gotchev  V. Yu. Glebov  V. N. Goncharov  D. R. Harding  P. A. Jaanimagi  J. P. Knauer  S. J. Loucks  L. D. Lund  J. A. Marozas  F. J. Marshall  R. L. Mccrory  P. W. Mckenty  S. F. B. Morse  P. B. Radha  W. Seka  S. Skupsky  H. Sawada  V. A. Smalyuk  J. M. Soures  C. Stoeckl  B. Yaakobi  J. A. Frenje  C. K. Li  R. D. Petrasso  F. H. SÉguin 《Astrophysics and Space Science》2005,298(1-2):227-233

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Jets And Arcs In The Coma Of Comet Hale-Bopp From August 1996 To April 1997     

LAFFONT  CÉLINE  ROUSSELOT  P.  CLAIREMIDI  J.  MOREELS  G.  BOICE  D. C. 《Earth, Moon, and Planets》1997,78(1-3):211-217

An observation program for measuring the activity of Comet Hale-Bopp was conducted at the Observatoire de Haute Provence from August 1996 to April 1997. Narrow band images were obtained from the 120 cm telescope. A set of four filters at 513, 516, 527 and 682 nm was used to measure the C₂ emission in the (1,1) and (0,0) band and the intensity of the dust-scattered continuum. The luminosity of the central part of the coma was measured in the continuum and C₂ emissions, as a function of heliocentric distance before perihelion. The activity of the comet considerably increased between October 1996 and February 1997. The images obtained in August, September and October 1996 show the presence of strong jets. In February, March and April 1997, series of roughly concentric arcs were observed in the sunward hemisphere of the coma. The arcs were also detected in the spatial distribution of the I(682 nm)/I(527 nm) red color ratio and the I(513 nm)/I(516 nm) C₂ emission ratio. Using the I(513 nm)/I(516 nm) ratio as a parameter to measure the degree of excitation of C₂ molecules, we can show that the local production of gas, probably resulting from dust fragmentation, should be taken into account. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献