Spatial Variability of Turbulent Mixing in the Abyssal Ocean   总被引：3，自引：0，他引：3  

KL Polzin  JM Toole  JR Ledwell  RW Schmitt 《Science (New York, N.Y.)》1997,276(5309):93-96

Ocean microstructure data show that turbulent mixing in the deep Brazil Basin of the South Atlantic Ocean is weak at all depths above smooth abyssal plains and the South American Continental Rise. The diapycnal diffusivity there was estimated to be less than or approximately equal to 0.1 x 10(-4) meters squared per second. In contrast, mixing rates are large throughout the water column above the rough Mid-Atlantic Ridge, and the diffusivity deduced for the bottom-most 150 meters exceeds 5 x 10(-4) meters squared per second. Such patterns in vertical mixing imply that abyssal circulations have complex spatial structures that are linked to the underlying bathymetry.  相似文献   

Public health. A sound rationale needed for phase III HIV-1 vaccine trials     

Burton DR  Desrosiers RC  Doms RW  Feinberg MB  Gallo RC  Hahn B  Hoxie JA  Hunter E  Korber B  Landay A  Lederman MM  Lieberman J  McCune JM  Moore JP  Nathanson N  Picker L  Richman D  Rinaldo C  Stevenson M  Watkins DI  Wolinsky SM  Zack JA 《Science (New York, N.Y.)》2004,303(5656):316

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Experimental transmission of Pasteurella multocida from raccoons to turkeys via bite wounds     

D A Gregg  L D Olson  E L McCune 《Avian diseases》1974,18(4):559-564

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Histologic pattern of testicular regrowths in caponized tom turkeys.     

R C Friedlander  L D Olson  E L McCune 《Avian diseases》1992,36(1):101-107

Testicular regrowths were observed in 10 of 21 tom turkeys between 28 and 32 weeks old, which was between 19 and 23 weeks after surgical caponization at 9 weeks of age. Regrowths were not observed in younger caponized toms. Two types of histologic patterns that differed from the normal pattern were observed in these regrowths. The first pattern was observed in seven regrowths and was characterized by a higher density of seminiferous tubules and more interstitial cells. The second pattern was seen in three regrowths and was characterized by extensive intertubular fibrosis, tubular detachment, and an increased number of interstitial cells. No correlation was found between the presence of these regrowths and plasma testosterone levels. The interstitial cell hyperplasia in all regrowths possibly was related to a diminished negative feedback by the endogenous testosterone on the release of luteinizing hormone from the pituitary. The appearance of regrowths at this age probably was related to the onset of normal physiological puberty.  相似文献   

Diagnostic methods used to monitor an outbreak of babesiosis (Babesia bovis) in a herd of feral cattle in New Caledonia     

T Hüe  M Graille  A Mortelecque  D Desoutter  JM Delathière  C Marchal  M Teurlai  N Barré 《Australian veterinary journal》2013,91(6):254-258

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Bovine viral diarrhoea virus in beef heifers in commercial herds in Australia: mob‐level seroprevalences and incidences of seroconversion,and vaccine efficacy     

JM Morton  NJ Phillips  LF Taylor  MR McGowan 《Australian veterinary journal》2013,91(12):517-524

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Failure of transfer of passive immunity and agammaglobulinaemia in calves in south‐west Victorian dairy herds: prevalence and risk factors     

Z Vogels  GM Chuck  JM Morton 《Australian veterinary journal》2013,91(4):150-158

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An initial evaluation of cattle showing clinical signs suggestive of malignant catarrhal fever in New Zealand and the results of a diagnostic quantitative PCR assay     

FI Hill  DJ Tisdall  JM Gill 《New Zealand veterinary journal》2013,61(5):302-303

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A Case of Successful Pregnancy in a Ewe with Uterus Didelphys     

DJ Carr  RP Aitken  JS Milne  AL David  JM Wallace 《Reproduction in domestic animals》2013,48(5):e78-e80

Uterus didelphys is a rare congenital abnormality of the reproductive tract. Although it occurs in various species, there are no published reports describing pregnancy outcome in association with this abnormality. Herein we describe a case of successful unilateral singleton pregnancy in a ewe incidentally found to have uterus didelphys during the course of a biomedical research study. The pregnancy was established using assisted reproductive techniques and interrupted in late gestation, at which point the abnormality was identified. Serial ultrasound assessment of foetal biometry revealed a normal foetal growth trajectory. Despite a 45% reduction in placentome number, total placentome weight was near normal secondary to compensatory placentome growth and development. To our knowledge, this is the first detailed report of normal foetal growth in an animal with uterus didelphys and illustrates the ability of the ovine placenta to adapt to a reduced number of placentomes and maintain foetal nutrient supply.  相似文献   

In Vitro Fertilization (IVF) in Straws and a Short Gamete Coincubation Time Improves the Efficiency of Porcine IVF     

C Almiñana  MA Gil  C Cuello  I Caballero  J Roca  JM Vazquez  EA Martinez 《Reproduction in domestic animals》2008,43(6):747-752

The present study was designed to evaluate three different in vitro fertilization (IVF) systems: a straw‐IVF system with 10 min of coincubation, a straw‐IVF system with 6‐h coincubation and the microdrop‐IVF system with 6‐h coincubation (the traditional IVF system used routinely in most of IVF laboratories) in an attempt to reduce polyspermic penetration ( Experiment 1 ). When the straw‐IVF system was tested in combination with two coincubation times, the use of 10 min of coincubation significantly increased (p < 0.001) the penetration rate and the efficiency of fertilization (67.7 ± 6.4% vs 31.9 ± 6.5% and 41.5 ± 2.5% vs 17.6 ± 2.5% for 10 min and 6 h, respectively), while there were no significant differences in the incidence of monospermy between both systems (64.3 ± 5.1% and 67.7 ± 3.4%, for 10 min and 6 h, respectively). The penetration rate in the 6‐h microdrop‐IVF system was higher (93.8 ± 3.6%; p < 0.001) compared with the 10‐min straw‐IVF system (67.7 ± 6.4%), however, monospermy was severely reduced (25.0 ± 4.3% vs 67.7 ± 3.4%, for the 6‐h microdrop‐IVF system and 10‐min straw‐IVF system, respectively). The efficiency of the IVF showed similar values between microdrop and 6‐h straw‐IVF systems, but efficiency was significantly improved (p < 0.05) when the 10‐min straw‐IVF system was used. Experiment 2 was designed to compare porcine in vitro embryo production in two IVF systems, the 6‐h microdrop‐IVF system (1000 sperm per oocyte) and 10‐min straw‐IVF system (30 000 sperm per oocyte). The blastocyst formation rates tended (p = 0.06) to be higher when the 10‐min straw‐IVF system was used compared with the 6‐h microdrop‐IVF system. In addition, the number of total cells per blastocyst increased significantly (p < 0.05) in the 10‐min straw‐IVF system. These results showed that the 10‐min straw‐IVF system is an effective way to decrease polyspermic penetration, and improve the efficiency of fertilization and the quality of blastocysts in terms of cell number per embryo.  相似文献