Quackgrass (Elytrigia repens) managed as a cover crop in herbicide-resistant silage corn     

NANCY GIFT  RUSSELL R. HAHN  JANE MT PLEASANT 《Weed Biology and Management》2008,8(3):154-160

The groundcover levels after corn ( Zea mays L.) silage harvest are rarely adequate to prevent soil erosion, but most corn-growers do not plant cover crops due to time and cost limitations. Herbicide-resistant corn hybrids provide opportunities to control weeds and to utilize cover crops in previously unexplored combinations. Field studies were conducted in 1999 and 2000 at Dryden and Valatie, New York, USA, to determine the potential for managing existing quackgrass ( Elytrigia repens [L.] Nevski) as a cover crop in herbicide-resistant silage corn. Three isolines of the corn hybrid, DKC493, were treated with glyphosate, glufosinate, primisulfuron, nicosulfuron or sethoxydim. Averaged over all site–years, the corn silage yields with glufosinate were similar to those with glyphosate. Glufosinate also resulted in a quackgrass ground cover greater than the 30% threshold for preventing soil erosion. Quackgrass could be managed as a perennial cover crop in silage corn–perennial forage dairy rotations in north-eastern USA.  相似文献   

Rapid fluctuations in sea level recorded at huon peninsula during the penultimate deglaciation     

TM Esat  MT McCulloch  J Chappell  B Pillans  A Omura 《Science (New York, N.Y.)》1999,283(5399):197-201

About 140,000 years ago, the breakup of large continental ice sheets initiated the Last Interglacial period. Sea level rose and peaked around 135,000 years ago about 14 meters below present levels. A record of Last Interglacial sea levels between 116,000 years to 136, 000 years ago is preserved at reef VII of the uplifted coral terraces of Huon Peninsula in Papua New Guinea. However, corals from a cave situated about 90 meters below the crest of reef VII are 130, 000 +/- 2000 years old and appear to have grown in conditions that were 6 degreesC cooler than those at present. These observations imply a drop in sea level of 60 to 80 meters. After 130,000 years, sea level began rising again in response to the major insolation maximum at 126,000 to 128,000 years ago. The early (about 140,000 years ago) start of the penultimate deglaciation, well before the peak in insolation, is consistent with the Devils Hole chronology.  相似文献   

13C-Depleted carbon microparticles in >3700-Ma sea-floor sedimentary rocks from west greenland     

MT Rosing 《Science (New York, N.Y.)》1999,283(5402):674-676

Turbiditic and pelagic sedimentary rocks from the Isua supracrustal belt in west Greenland [more than 3700 million years ago (Ma)] contain reduced carbon that is likely biogenic. The carbon is present as 2- to 5-micrometer graphite globules and has an isotopic composition of delta13C that is about -19 per mil (Pee Dee belemnite standard). These data and the mode of occurrence indicate that the reduced carbon represents biogenic detritus, which was perhaps derived from planktonic organisms.  相似文献   

Coral record of equatorial sea-surface temperatures during the penultimate deglaciation at huon peninsula     

MT McCulloch  AW Tudhope  TM Esat  GE Mortimer  J Chappell  B Pillans  AR Chivas  A Omura 《Science (New York, N.Y.)》1999,283(5399):202-204

Uplifted coral terraces at Huon Peninsula, Papua New Guinea, preserve a record of sea level, sea-surface temperature, and salinity from the penultimate deglaciation. Remnants have been found of a shallow-water reef that formed during a pause, similar to the Younger Dryas, in the penultimate deglaciation at 130,000 +/- 2000 years ago, when sea level was 60 to 80 meters lower than it is today. Porites coral, which grew during this period, has oxygen isotopic values and strontium/calcium ratios that indicate that sea-surface temperatures were much cooler (22 degrees +/- 2 degreesC) than either Last Interglacial or present-day tropical temperatures (29 degrees +/- 1 degreesC). These observations provide further evidence for a major cooling of the equatorial western Pacific followed by an extremely rapid rise in sea level during the latter stages of Termination II.  相似文献   

Comparison of the Johne''s absorbed EIA and the complement-fixation test for the diagnosis of Johne''s disease in cattle   总被引：2，自引：0，他引：2  

SE RIDGE  IR MORGAN  DC SOCKETT†  MT COLLINS†  RJ CONDRON  NW SKILBECK†  JJ WEBBER§ 《Australian veterinary journal》1991,68(8):253-257

A commercially available absorbed ELISA for the diagnosis of Johne's disease (JD) (paratuberculosis) in cattle, the Johne's Absorbed EIA, was compared with the conventional complement-fixation test (CFT) used in Australia. Stored plasma from 3 Victorian dairy herds with a history of JD, sera from specimens submitted from animals showing clinical signs of JD and sera from the US National Repository for Paratuberculosis Specimens were used to determine the sensitivity of each test. The EIA detected 48.8% of 43 Australian animals with subclinical JD, while the CFT detected only 12 (21.4%) of 56 subclinically affected cattle. Of 150 subclinically infected US cattle, the EIA detected 47.3% and the CFT detected 52.0%. The EIA detected 59.7% of animals which at the time of sampling were shedding Mycobacterium paratuberculosis in their faeces, but showed no clinical signs of JD, while the CFT detected 57.3%. The EIA correctly identified 88.2% of 136 histologically confirmed clinical cases, and the CFT detected 83.4%. The specificity of each test was determined by testing sera collected at slaughter from animals residing in a known JD-free area of Australia, and from samples from the US National Repository of Paratuberculosis Specimens collected from certified-free herds in Wisconsin. The EIA was found to have a specificity of 99.8% when 998 Australian animals were used as the test population, and 99.0% when 196 US animals were used. The specificity of the CFT using Australian samples was 96.9% and 95.2% using American samples.  相似文献   

Performance characteristics of the turbidimetric ACL‐TOP CTS 300 coagulation analyzer in dogs and cats          下载免费PDF全文

Leslie C. Sharkey DVM  PhD  DACVP  Kim J. Little ASCP  Kevin D. Williams MT  Jeffrey M. Todd DVM  DACVECC  Rae Richardson DVM  Angela D. Gwynn DVM  Aaron Rendahl PhD 《Journal of Veterinary Emergency and Critical Care》2018,28(4):317-325

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Diagnostic challenge: right head tilt and depression in a dog     

MD Chalkley  MT Bouljihad 《Australian veterinary journal》2014,92(3):85-87

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Nitric Oxide and Superoxide Anion Production During Heparin‐Induced Capacitation in Cryopreserved Bovine Spermatozoa     

PC Rodriguez  LB Valdez  T Zaobornyj  A Boveris  MT Beconi 《Reproduction in domestic animals》2011,46(1):74-81

The aim of this work was to quantify NO, O₂^? and ONOO^? production during heparin‐induced capacitation of cryopreserved bovine spermatozoa. A time dependent hyperbolic increase was observed for heparin‐dependent capacitation, O₂ uptake, and NO production. Conversely, O₂^? production was increased during the first 15 min of incubation, showing a decrease from this time until 45 min. At 15 min of heparin incubation, a threefold increase in O₂ consumption (5.9 ± 0.6 nmol/min × 10⁷ cells), an enhancement in NO release (1.1 ± 0.2 nmol/min × 10⁷ cells), and a five‐fold increase in O₂^? production (1.3 ± 0.07 nmol/min × 10⁷ cells), were observed. Peroxynitrite production rate was estimated taking into account NO and O₂^? generation and the second‐order rate constant of the reaction between these species. To conclude, heparin‐induced capacitation of cryopreserved bovine spermatozoa activates (i) mitochondrial O₂ uptake by high ADP levels due to increased energy requirements, (ii) NO production by a constitutive NOS and (iii) O₂^? production by a membrane‐bound NAD(P)H oxidase. The products of both enzymes are released to the extracellular space and could be involved in the process of sperm capacitation.  相似文献   

Management of mycotic keratitis in a horse using a conjunctival pedicle graft     

MB COLLINS  MT ETHELL  DR HODGSON 《Australian veterinary journal》1994,71(9):298-299

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Temperature and surface-ocean water balance of the mid-holocene tropical western pacific     

MK Gagan  LK Ayliffe  D Hopley  JA Cali  GE Mortimer  J Chappell  MT McCulloch  MJ Head 《Science (New York, N.Y.)》1998,279(5353):1014-1018

Skeletal Sr/Ca and 18O/16O ratios in corals from the Great Barrier Reef, Australia, indicate that the tropical ocean surface approximately 5350 years ago was 1 degrees C warmer and enriched in 18O by 0.5 per mil relative to modern seawater. The results suggest that the temperature increase enhanced the evaporative enrichment of 18O in seawater. Transport of part of the additional atmospheric water vapor to extratropical latitudes may have sustained the 18O/16O anomaly. The reduced glacial-Holocene shift in seawater 18O/16O ratio produced by the mid-Holocene 18O enrichment may help to reconcile the different temperature histories for the last deglaciation given by coral Sr/Ca thermometry and foraminiferal oxygen-isotope records.  相似文献