大学英语等级考试的信度与效度测试:英语四、六级与有效交际能力     

余郑璟 《成都信息工程学院学报》2002,17(2):138-148

关于大学英语四、六级,及其英语口语考试,是否具有科学的信度与效度这一问题的论证,引起了诸多争议。运用Carl Popper的反证法,在怀疑并否定其具有科学信度与效度方面,也不乏许多挑战权威的例子。尽管现今反证的理论与例证并不十分系统,但它终将会以科学的信度与效度为目标而日臻完善。  相似文献   

Genesis of copper mineralisation,Myall Creek prospect,South Australia     

Ian B. Lambert  Janice Knutson  Terrence H. Donnelly  Hashem Etminan  Malcolm G. Mason 《Mineralium Deposita》1984,19(4):266-273

The Myall Creek copper prospect is in unmetamorphosed carbonaceous dolosiltstone and sandstone at the base of the late Proterozoic (Adelaidean) Tapley Hill Formation. It contains disseminated, fine-grained chalcopyrite, zincian tennanite, bornite, chalcocite, pyrite, sphalerite and galena, and irregular to straight chalcopyrite-rich veinlets. Some ore minerals rim and/or partially replace pyrite or clastic grains. There is no evidence of hydrothermal activity. The ³⁴S_CDT values of pyrite and the other sulfides fall in the wide range –3.6 to +44.2. Dolomite in both mineralised and unmineralised samples has ¹³C_PDB values concentrated around –3, and ¹⁸O_SMOW values around +25. It is concluded that the mineralising fluids were near-neutral brines which leached metals from the basement and early Adelaidean rocks. They entered the Tapley Hill sediments at moderately low temperatures via permeable strata and faults. The metals were precipitated by biogenic H₂S, and also fixed by reaction with iron sulfides and, possibly, organic matter. Continuing ascent of brines into the mineralised strata caused breakdown of detrital feldspars and Fe-Ti oxides, and some solution-remobilisation of early-formed sulfides.  相似文献   

The solar Ca II K index and the Mg II core-to-wing ratio     

R. F. Donnelly  O. R. White  W. C. Livingston 《Solar physics》1994,152(1):69-76

The 1 index of the solar Ca II K line is compared with the core-to-wing ratio of satellite measurements of the Mg II h and k lines. The correlation coefficient r = 0.976 for the Nimbus-7 Mg II ratio during solar cycle 21 andr = 0.99 for the NOAA9 Mg II ratio in cycle 22. Linear regression analysis for the full dynamic range of both data sets is used to combine the Nimbus-7 and NOAA9 Mg II data. These relations permit the ground-based Ca K index to estimate the solar UV flux.  相似文献   

Sur la structure,l'âge et l'origine des « brèches de Bosmendiette » (Pyrénées-Atlantiques)     

Joseph Canérot  Jacques Bauer  Michel Bilotte  Chantal Bourdillon  Jean-Paul Colin  Elie-Jean Debroas  Françoise Magniez  Francis Mediavilla  Yves Ternet 《Comptes Rendus Geoscience》2004,336(10):951-958

By us considered as Albo-Aptian in age and generated through halokinetic processes, the Bosmendiette breccias have been recently interpreted as Selandian (Palaeocene) globigerine-bearing sediments deposited in sub-marine canyons within a deep trough crossing the Pyrenees, from the Mediterranean Sea to the Atlantic Ocean. These breccias are really azoic in their lower part and contain a scarce microfauna including radolarians and benthic foraminifera at the top of the formation. They are unconformably covered by the Urgo-Aptian limestones and marls and indicate, under opening marine conditions, Lower Cretaceous collapse movements and northward sliding of the Jurassic slumped cover, related to the growth of the Béloscare–Apoura diapir. To cite this article: J. Canérot et al., C. R. Geoscience 336 (2004).  相似文献   

Méthodologie de l'extraction des hydrocarbures aromatiques polycycliques. Application à des sédiments de la lagune de Bizerte (Tunisie)Methodology of extraction of polycyclic aromatic hydrocarbons. Application to sediment from the Bizerte Lagoon (Tunisia)     

Nadia Mzoughi  Fayçal Hellal  Mohamed Dachraoui  Jean-Pierre Villeneuve  Chantal Cattini  Stephen J de Mora  Amor El Abed 《Comptes Rendus Geoscience》2002,334(12):893-901

The marine environment is very complex, with several important chemical, biological, and sedimentological interactions. Sediments constitute a reservoir for numerous pollutants, including polycyclic aromatic hydrocarbons (PAHs). PAHs are known by their mutagenic and/or carcinogenic effect. This study evaluates contamination levels in Bizerte Lagoon with respect to PAHs. The extraction efficiency of PAHs from sediment has been evaluated using Soxhlet or ultrasonic procedures, based on the recovery of an internal standard (9,10-dihydroanthracene). Several PAHs were found, including sixteen that are reported in the priority list of pollutants of the US Environmental Protection Agency (EPA). PAHs analysis was carried out by GC–FID and GC–MS for 16 samples sampled in two seasons: summer and winter. Results permit an assessment of PAHs pollution in the Bizerte Lagoon. To cite this article: N. Mzoughi et al., C. R. Geoscience 334 (2002) 893–901.  相似文献   

Axial magnetic anomalies over slow-spreading ridge segments: insights from numerical 3-D thermal and physical modelling     

Sébastien Gac  Jérôme Dyment  Chantal Tisseau  Jean Goslin 《Geophysical Journal International》2003,154(3):618-632

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Geostatistics for assessing the efficiency of a distributed physically‐based water quality model: application to nitrate in the Seine River     

Edwige Polus  Nicolas Flipo  Chantal de Fouquet  Michel Poulin 《水文研究》2011,25(2):217-233

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Incorporating landscape features to obtain an object‐oriented landscape drainage network representing the connectivity of surface flow pathways over rural catchments     

Chantal Gascuel‐Odoux  Pierre Aurousseau  Thibaut Doray  Hervé Squividant  Francis Macary  Daniel Uny  Catherine Grimaldi 《水文研究》2011,25(23):3625-3636

A topological representation of a rural catchment is proposed here in addition to the generally used topographic drainage network. This is an object‐oriented representation based on the identification of the inlets and outlets for surface water flow on each farmer's field (or plot) and their respective contributing areas and relationships. It represents the catchment as a set of independent plot outlet trees reaching the stream, while a given plot outlet tree represents the pattern of surface flow relationships between individual plots. In the present study, we propose to implement functions related to linear and surface elements of the landscape, such as hedges or road networks, or land use, to obtain what we call a landscape drainage network which delineates the effective contributing area to the stream, thus characterizing its topological structure. Landscape elements modify flow pathways and/or favour water infiltration, thus reducing the area contributing to the surface yield and modifying the structure of the plot outlet trees. This method is applied to a 4·4‐km² catchment area comprising 43 955 pixels and 312 plots. While the full set of 164 plot outlet trees, with an average of 7 plots per tree, covers 100% of the total surface area of the catchment, the landscape drainage network comprises no more than 37 plot outlet trees with an average of 2 plots per tree, accounting for 52 and 7% of the catchment surface area, when taking account of linear elements and land use, respectively. This topological representation can be easily adapted to changes in land use and land infrastructure, and provides a simple and functional display for intercomparison of catchments and decision support regarding landscape and water management. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Repeated century-scale droughts over the past 13,000 yr near the Hudson River watershed, USA     

Paige E. Newby  Bryan N. Shuman  Jeffrey P. Donnelly  Dana MacDonald 《Quaternary Research》2011,75(3):523-530

Long-term sediment and ground-penetrating radar data from Davis Pond, a small lake near the Hudson River valley, reveal past droughts in a historically humid region that presently supplies water to millions of people in and around New York City. A minimum of eleven sandy paleoshoreline deposits in the lake date from 13.4 to 0.6 cal ka BP. The deposits span 1500 to 200 yr between bracketing radiocarbon ages, and intrude into lacustrine silts up to 9.0 m below the modern lake surface in a transect of six sediment cores. Three low stands, ca. 13.4–10.9, 9.2 and 8.2 cal ka BP indicate low regional moisture balance when low temperatures affected the North Atlantic region. Consistent with insolation trends, water levels rose from ca. 8.0 cal ka BP to present, but five low stands interrupted the rise and are likely associated with ocean–atmosphere interactions. Similar to evidence from other studies, the data from Davis Pond indicate repeated multi-century periods of prolonged or frequent droughts super-imposed on long-term regional trends toward high water levels. The patterns indicate that water supplies in this heavily populated region have continuously varied at multiple time scales and confirm that humid regions such as the northeastern United States are more prone to severe drought than historically expected.  相似文献   

Sextet transitions in Fe ii     

M. P. Donnelly  A. Hibbert 《Monthly notices of the Royal Astronomical Society》2001,321(2):247-253

We have calculated oscillator strengths for the J – J ' levels of the a  ⁶D– z  ⁶P^o, the a  ⁶D– z  ⁶D^o and the a  ⁶D– z  ⁶F^o multiplets in Fe  ii , using configuration interaction wave functions. The importance of the mixing of the ⁶P^o, ⁶D^o and ⁶F^o states is shown, as is the effect of core polarization of both the 3 p and 3 s orbitals. Good agreement with recent experimental results is obtained.  相似文献