Effect of Cryopreservation on Bovine Sperm Viability as Determined by Dual DNA Staining     

DL Garner  CA Thomas  CH Allen  PL Senger  RG Sasser 《Reproduction in domestic animals》1997,32(6):279-283

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Reproductive and vegetative morphology of a cretaceous angiosperm     

Dilcher DL  Crepet WL  Beeker CD  Reynolds HC 《Science (New York, N.Y.)》1976,191(4229):854-856

Recent collections from plant-bearing deposits of Cenomanian age in central Kansas have yielded angiosperm axes with helically arranged, seed-bearing, conduplicate carpels. Large leaves associated with these fruits are thought to represent parts of the same kind of plant because the leaves and fruits are the only plant fossils at this locality to have distinctive, morphologically identical, yellow bodies within their carbonaceous remains. These fossils provide a rare opportunity to study the morphology of an ancient angiosperm and illustrate the antiquity of certain features considered primitive by comparative angiosperm morphologists.  相似文献   

Yellow traps as an aid in fish farming     

S. ERHARD  H. KRATOCHVIL  M. LÖDL 《Aquaculture Research》1993,24(1):129-131

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Eocene Epiphyllous Fungi     

Dilcher DL 《Science (New York, N.Y.)》1963,142(3593):667-669

Fossil fungi belonging to the Meliolaceae and Microthyriaceae were found in Eocene deposits in Tennessee. Germinated spores for each form of fungus were identified. One of the two forms of the genus Meliola, (Meliolaceae) appears to have parasitized the leaf upon which it grew. The vegetative, sexual, and asexual reproductive structures are preserved in a member of the genus Asterina (Microthyriaceae). The discovery of these fungi indicates that Western Tennessee was warm and humid during the Eocene.  相似文献   

Lunar surface magnetic fields and their interaction with the solar wind: results from lunar prospector   总被引：1，自引：0，他引：1  

RP Lin  DL Mitchell  DW Curtis  KA Anderson  CW Carlson  J McFadden  MH Acuna  LL Hood  A Binder 《Science (New York, N.Y.)》1998,281(5382):1480-1484

The magnetometer and electron reflectometer experiment on the Lunar Prospector spacecraft has obtained maps of lunar crustal magnetic fields and observed the interaction between the solar wind and regions of strong crustal magnetic fields at high selenographic latitude (30 degreesS to 80 degreesS) and low ( approximately 100 kilometers) altitude. Electron reflection maps of the regions antipodal to the Imbrium and Serenitatis impact basins, extending to 80 degreesS latitude, show that crustal magnetic fields fill most of the antipodal zones of those basins. This finding provides further evidence for the hypothesis that basin-forming impacts result in magnetization of the lunar crust at their antipodes. The crustal magnetic fields of the Imbrium antipode region are strong enough to deflect the solar wind and form a miniature (100 to several hundred kilometers across) magnetosphere, magnetosheath, and bow shock system.  相似文献   

Frictional melting during the rupture of the 1994 bolivian earthquake   总被引：1，自引：0，他引：1  

H Kanamori  DL Anderson  TH Heaton 《Science (New York, N.Y.)》1998,279(5352):839-842

The source parameters of the 1994 Bolivian earthquake (magnitude Mw = 8.3) suggest that the maximum seismic efficiency eta was 0.036 and the minimum frictional stress was 550 bars. Thus, the source process was dissipative, which is consistent with the observed slow rupture speed, only 20% of the local S-wave velocity. The amount of nonradiated energy produced during the Bolivian rupture was comparable to, or larger than, the thermal energy of the 1980 Mount St. Helens eruption and was sufficient to have melted a layer as thick as 31 centimeters. Once rupture was initiated, melting could occur, which reduces friction and promotes fault slip.  相似文献   

Synchronous climate changes in antarctica and the north atlantic     

EJ Steig  EJ Brook  JWC White  CM Sucher  ML Bender  SJ Lehman  DL Morse  ED Waddington  GD Clow 《Science (New York, N.Y.)》1998,282(5386):92-95

Central Greenland ice cores provide evidence of abrupt changes in climate over the past 100,000 years. Many of these changes have also been identified in sedimentary and geochemical signatures in deep-sea sediment cores from the North Atlantic, confirming the link between millennial-scale climate variability and ocean thermohaline circulation. It is shown here that two of the most prominent North Atlantic events-the rapid warming that marks the end of the last glacial period and the Bolling/Allerod-Younger Dryas oscillation-are also recorded in an ice core from Taylor Dome, in the western Ross Sea sector of Antarctica. This result contrasts with evidence from ice cores in other regions of Antarctica, which show an asynchronous response between the Northern and Southern Hemispheres.  相似文献   

Seroprevalence to Leptospira interrogans serovar hardjo in Merino stud rams in South Australia     

GR ELLIS  DL PARTINGTON†  M. HINDMARSH‡  MD BARTON 《Australian veterinary journal》1994,71(7):203-206

Summary A serological survey of 2160 Merino stud rams on 36 farms detected positive reactions greater than or equal to 1/100 in 42% of animals using the microscopic agglutination test (MAT) to Leptospira interrogans serovar hardjo. Twenty flocks had seroprevalence values greater than 30% with 15 flocks having values 60%. The enzymelinked immunosorbent assays showed that 47% and 3% of rams on the 36 farms were positive for IgG and IgM antibodies, respectively. Forty-five percent of hardjo reactions were in rams that had not been exposed to cattle. Significant correlations were found between IgM reactors and creek/dam water pumped into troughs, and between MAT/IgG reactors and total flock size. No statistical relationships were detected between positive reactors and two different annual average rainfall gradients, the time of the year in which samples were obtained, or agricultural regions of South Australia. Infections with an organism of the Sejroe serogroup is widespread in Merino stud rams.  相似文献   

Podocarpus from the eocene of north america     

Dilcher DL 《Science (New York, N.Y.)》1969,164(3877):299-301

A few leafy gymnosperm shoots were found in Eocene deposits of southeastern North America. Similar fossil material from Tertiary deposits in North America has been identified as Taxodium, Taxites, and Sequoia. This new fossil material is not related to these genera but belongs to Podocarpus section Stachycarpus. This is the first fossil record of this section in North America.  相似文献   

Clinical presentation and treatment of tick paralysis in dogs and cats in Sydney (2001–2010)     

MN Westwood  DL Emery  NK Dhand 《Australian veterinary journal》2013,91(12):491-498

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