Penny ice cap cores, baffin island, canada, and the wisconsinan foxe dome connection: two states of hudson bay ice cover     

DA Fisher  RM Koerner  JC Bourgeois  G Zielinski  C Wake  CU Hammer  HB Clausen  N Gundestrup  S Johnsen  K Goto-Azuma  T Hondoh  E Blake  M Gerasimoff 《Science (New York, N.Y.)》1998,279(5351):692-695

Ice cores from Penny Ice Cap, Baffin Island, Canada, provide continuous Holocene records of oxygen isotopic composition (delta18O, proxy for temperature) and atmospheric impurities. A time scale was established with the use of altered seasonal variations, some volcanic horizons, and the age for the end of the Wisconsin ice age determined from the GRIP and GISP2 ice cores. There is pre-Holocene ice near the bed. The change in delta18O since the last glacial maximum (LGM) is at least 12.5 per mil, compared with an expected value of 7 per mil, suggesting that LGM ice originated at the much higher elevations of the then existing Foxe Dome and Foxe Ridge of the Laurentide Ice Sheet. The LGM delta18O values suggest thick ice frozen to the bed of Hudson Bay.  相似文献   

Strong regularities in world wide web surfing   总被引：5，自引：0，他引：5  

BA Huberman  PLT Pirolli  JE Pitkow  RM Lukose 《Science (New York, N.Y.)》1998,280(5360):95-97

One of the most common modes of accessing information in the World Wide Web is surfing from one document to another along hyperlinks. Several large empirical studies have revealed common patterns of surfing behavior. A model that assumes that users make a sequence of decisions to proceed to another page, continuing as long as the value of the current page exceeds some threshold, yields the probability distribution for the number of pages that a user visits within a given Web site. This model was verified by comparing its predictions with detailed measurements of surfing patterns. The model also explains the observed Zipf-like distributions in page hits observed at Web sites.  相似文献   

The structure of the upper atmosphere of mars: In situ accelerometer measurements from mars global surveyor   总被引：1，自引：0，他引：1  

GM Keating  SW Bougher  RW Zurek  RH Tolson  GJ Cancro  SN Noll  JS Parker  TJ Schellenberg  RW Shane  BL Wilkerson  JR Murphy  JL Hollingsworth  RM Haberle  M Joshi  JC Pearl  BJ Conrath  MD Smith  RT Clancy  RC Blanchard  RG Wilmoth  DF Rault  TZ Martin  DT Lyons  PB Esposito  MD Johnston  al et 《Science (New York, N.Y.)》1998,279(5357):1672-1676

The Mars Global Surveyor (MGS) z-axis accelerometer has obtained over 200 vertical structures of thermospheric density, temperature, and pressure, ranging from 110 to 170 kilometers, compared to only three previous such vertical structures. In November 1997, a regional dust storm in the Southern Hemisphere triggered an unexpectedly large thermospheric response at mid-northern latitudes, increasing the altitude of thermospheric pressure surfaces there by as much as 8 kilometers and indicating a strong global thermospheric response to a regional dust storm. Throughout the MGS mission, thermospheric density bulges have been detected on opposite sides of the planet near 90 degreesE and 90 degreesW, in the vicinity of maximum terrain heights. This wave 2 pattern may be caused by topographically-forced planetary waves propagating up from the lower atmosphere.  相似文献   

Leukoencephalomalacia in horses     

RM CHRISTLEY  AP BEGG  DR HUTCHINS  DR HODGSON  WL BRYDEN 《Australian veterinary journal》1993,70(6):225-226

  相似文献   

Field trials of a formulation containing moxidectin and 6 in 1 vaccines for sheep     

CL SCHWARTZKOFF  RM COBB 《Australian veterinary journal》1996,74(3):225-227

Objective: To assess the efficacy and safety of a formulation containing moxidectin and 6 in 1 vaccine in sheep under field conditions.
Design: Efficacy and safety study.
Animals: Two hundred and five crossbred Merino lambs and two hundred and eight Merino ewes were used in the studies.
Procedure: A formulation was made for the simultaneous treatment of sheep with moxidectin and immunisation against clostridial diseases and caseous lymphadenitis. The efficacy against nematodes, vaccine response and safety were assessed.
Results: Effective control of nematodes and responses to antigens were achieved following subcutaneous administration. The formulation was safe to administer; occasional minor tissue reactions were evident, but no other adverse effects of treatment were observed in either pregnant ewes or lambs, using either the recommended dose, or an overdose of the formulation.
Conclusion: Administration of a formulation containing moxidectin, five clostridial antigens and caseous lymphadenitis antigen proved safe and efficacious under field conditions.  相似文献   

Patterns of Follicular Growth in Superovulated Sheep and Influence on Endocrine and Ovarian Response     

A Gonzalez-Bulnes  RM Garcia-Garcia  CJH Souza  J Santiago-Moreno  A Lopez-Sebastian  MJ Cocero  DT Baird 《Reproduction in domestic animals》2002,37(6):357-361

Objectives of this study were to characterize patterns of follicular development in sheep superovulated with purified follicle stimulating hormone (FSH) (OVAGEN^TM, ICP, Auckland, New Zealand) and to determine its influence on preovulatory events (onset of the oestrus behaviour and timing of the preovulatory luteinizing hormone surge) and ovarian response (ovulation rate and embryo yield). Number and size of all ≥ 23 mm follicles from the first FSH injection to withdrawal of progestagen sponges was determined by transrectal ultrasonography just prior to every FSH injection in nine Manchega ewes superovulated with eight decreasing doses (ml) (1.5 × 3, 1.25 × 2 and 1 × 3) of OVAGEN injected twice daily from 60 h before to 24 h after the withdrawal of 40 mg fluorogestone acetate sponges. Oestrous detection and jugular blood sampling for LH radioimmunoassay were performed every 3 h from 14 to 53 h after sponge removal and ovulation rate and number of embryos were determined 4 days after progestagen withdrawal. Administration of OVAGEN induced a significant rise (p < 0.0005) in the number of follicles ≥ 4 mm in size because of an increased growth in size of follicles from the first FSH injection to sponge removal, an increase in the number of newly detected follicles from 12 to 36 h of the first FSH dose (p < 0.005) and a decrease in regression rate from 24 h (p < 0.001). The number of follicles 2–3 mm in size at first FSH dose (10.4 ± 1.5) was positively correlated with the number of ≥ 4 mm follicles at 0 h (19.0 ± 2.7, p < 0.01). A higher number of ≥ 4 mm follicles at 0 h was related with an earlier appearance of oestrus (31.5 ± 1.5 h, p = 0.08) and LH surge (45.0 ± 2.3 h, p < 0.005), and a higher ovulation rate (18.2 ± 3.8, p < 0.005). On the other hand, the rate of embryo recovery was decreased in ewes with earlier preovulatory LH peaks (p < 0.005), with a shorter interval between oestrus and LH peak (p < 0.05).  相似文献   

The 1872 outbreak of foot-and-mouth disease in Australia why didnt it become established?     

CM BUNN  MG GARNER  RM CANNON 《Australian veterinary journal》1998,76(4):262-269

  相似文献   

Expression profiles of immunity and reproductive genes during transition period in Holstein cattle          下载免费PDF全文

AI Ateya  MS Hussein  HM Ghanem  RM Saleh  WB El‐Domany  YY Elseady 《Reproduction in domestic animals》2018,53(2):352-358

The transition period is a critical time for dairy cows as the animal is subjected to the physiological stress accompanying parturition. Immunosuppression and health status were examined during this period in 80 Holstein cows. Blood samples were taken from each cow 3, 2 and 1 week before and after calving, and at calving (0 day). RNA was extracted and subjected to real‐time PCR to determine mRNA levels for the immune‐related genes TLR 2, 4, 6, 7 and β‐defensin 5 in addition to the reproduction‐related genes prolactin and IGF‐I. Results showed significant up‐regulation of pro‐inflammatory‐selected genes, TLR 4, 6 7 and β‐defensin 5 at the third‐week post‐calving; however, earlier periods had lower expression of such genes. In contrast, the immunosuppression biomarker TLR2 gene was up‐regulated at calving and 1 week after parturition and then down‐regulated again at second and third week. Prolactin and IGF‐I genes expression levels were significantly and gradually increased mainly post‐partum. This research highlights that the expression patterns of TLRs, BNBD5, PRL and IGF‐I could be biomarkers to follow up immune and reproductive status of dairy cow at peri‐parturient period to predict the most susceptible risk time for disease incidence and to build up management protocol.  相似文献   

Retracted: Influence of Glutamine Supplementation on Motility and Fertilization Success of Frozen–Thawed Persian Sturgeon (Acipenser persicus) Sperm          下载免费PDF全文

MS Aramli  K Golshahi  RM Nazari  A Golpour  S Aramli 《Reproduction in domestic animals》2016,51(4):474-477

Amino acids have an important biological role for the prevention of cell damage during cryopreservation. The aim of this study was to investigate the effects of glutamine on post‐thaw sperm motility and fertilization success in the Persian sturgeon (Acipenser persicus). Sperm collected from six fish was cryopreserved in extenders containing different glutamine concentrations (2.5, 5 and 10 mm ). Sperm samples diluted at the ratio of 1 : 1 using the extenders were subjected to cryopreservation. After dilution, the sperm suspensions were sucked into 250‐μl straws; the straws were placed on the tray, frozen in nitrogen vapour and plunged into liquid nitrogen. Then, sperm were thawed in a water bath at 40°C for 5 s and used for analysis. Our results revealed that an increase in the concentration of glutamine caused a significant increase in the motility percentage, curvilinear velocity (VCL) and also fertilization success in the Persian sturgeon (p < 0.05). Comparing all concentrations of glutamine, the best concentration for sperm motility and fertilization rate was 10 mm . In addition, higher post‐thaw motility percentage, VCL, and fertilization and hatching rates were obtained with the extender at the concentration of 10 mm (p < 0.05). The findings of this study showed that glutamine was of greater benefit to Persian sturgeon sperm motility during frozen–thawed process.  相似文献   

Influence of Gonadotrophin‐Induced First Oestrus on Gilt Fertility     

DM Hidalgo  RM Friendship  L Greiner  R Manjarín  MR Amezcua  JC Domínguez  RN Kirkwood 《Reproduction in domestic animals》2014,49(6):899-902

The aim of this study was to determine the association between the oestrous response of pre‐pubertal gilts to gonadotrophin injection or boar exposure and their subsequent farrowing rate and litter size. At 154 days of age, randomly selected pre‐pubertal gilts received an intramuscular injection of 400 IU equine chorionic gonadotrophin plus 200 IU human chorionic gonadotrophin (PG600^®; Merck Animal Health; n = 181). From the remaining pool of animals not treated with hormones, the first gilts showing signs of oestrus were selected to act as controls (n = 201). Boar exposure began at 155 days of age for both groups, and gilts were bred at a weight of approximately 130 kg. Comparisons were made between PG600^®‐treated gilts exhibiting oestrus or not within 7 days post‐injection (early and late responders, respectively) and control gilts exhibiting oestrus or not within 30 days after beginning of boar exposure (select and non‐select control gilts, respectively). By 162 days, oestrus was detected in 67.5% of PG600^®‐treated gilts compared with 5.7% of control gilts (p < 0.0001). The proportion of animals observed in oestrus at least three times before breeding was greater for select control gilts compared with early and late responder PG600^®‐treated gilts (p ≤ 0.001). There were no significant differences in farrowing rate and litter size between the four treatment groups. These data indicate that PG600^® is an effective tool to induce an earlier oestrus in gilts, that subsequent farrowing rate and born alive litter size compare favourably to that of select gilts and that gilts failing to respond promptly to hormonal stimulation do not exhibit compromised fertility.  相似文献