Off-axis crustal thickness across and along the east pacific rise within the MELT area   总被引：1，自引：0，他引：1  

JP Canales  RS Detrick  S Bazin  AJ Harding  JA Orcutt 《Science (New York, N.Y.)》1998,280(5367):1218-1221

Wide-angle seismic data along the Mantle Electromagnetic and Tomography (MELT) arrays show that the thickness of 0.5- to 1. 5-million-year-old crust of the Nazca Plate is not resolvably different from that of the Pacific Plate, despite an asymmetry in depth and gravity across this portion of the East Pacific Rise. Crustal thickness on similarly aged crust on the Nazca plate near a magmatically robust part of the East Pacific Rise at 17 degrees15'S is slightly thinner (5.1 to 5.7 kilometers) than at the 15 degrees55'S overlapping spreading center (5.8 to 6.3 kilometers). This small north-south off-axis crustal thickness difference may reflect along-axis temporal variations in magma supply, whereas the across-axis asymmetry in depth and gravity must be caused by density variations in the underlying mantle.  相似文献   

Management of bilateral flexural deformity of the metacarpophalangeal joints in three alpaca crias     

T CASHMAN  AJ DART  A O''SHEA  DR HODGSON 《Australian veterinary journal》1999,77(8):508-510

Three neonatal alpacas were treated for MCP flexural deformities. Two crias responded well to conservative therapy using splints made from fibreglass cast material. One cria with severe deformity failed to respond to conservative treatment but recovered satisfactorily after transection of the suspensory ligament in both legs. It seems that mild cases of flexural deformity of the MCP joint in alpaca crias respond well to conservative therapy but that surgical correction may be required in more severe cases. Sequential transection of the structures limiting extension of the MCP joint may result in fewer complications than previously reported techniques.  相似文献   

Effects of thyroxine administration on the growth and survival of pike silverside (Chirostoma estor) juveniles     

Pamela Navarrete‐Ramírez  Aurea Orozco  Carlos Valverde‐R  Aurora Olvera  Elva Mayra Toledo‐Cuevas  LG Ross  CA Martínez‐Palacios 《Aquaculture Research》2011,42(6):808-814

The pike silverside has high aquaculture potential despite its slow growth. In this study, thyroxine (T₄) concentrations (0.13, 1.3 and 13 nM), a control with no hormonal supplement and a negative control containing 4.5 mM methimazole (MMI) were tested to evaluate the growth of this species. Juveniles (0.2 g) were exposed by immersion to these treatments for 8 h every second day for 120 days, and growth evaluations were performed monthly over the entire trial period. In addition, tissue samples from each treatment group were assayed for triiodothyronine (T₃) and deiodinase type 2 (D2) activity . The survival rates in all T₄ groups were high, and a significant increase in growth was observed (average of 58%). The MMI treatment caused an increase in mortality and a reduction in the final body weight compared with the control. T₄ administration did not affect the tissue levels of T₃, and it decreased muscular D2 activity only after 30 days of exposure. These results demonstrated that low concentrations of T₄ in the culture environment could improve the growth of this species without affecting tissue hormone levels. The technique may have useful applications for early‐stage aquaculture of this and other economically important species.  相似文献   

Advances in the study of activity additivity of supplemented proteases to improve digestion of feed protein by Penaeus vannamei          下载免费PDF全文

J.H. Córdova‐Murueta  M.A. Navarrete‐del‐Toro  F.L. García‐Carreño 《Aquaculture Nutrition》2017,23(2):414-421

In vitro assays used porcine or bovine trypsin as models of exogenous enzymes to determine functioning in the presence of enzymatic extracts from the digestive gland of whiteleg shrimp Penaeus vannamei. Using electrophoresis and zymograms, when enzymes from the shrimp were mixed in the absence of protein substrate, they hydrolysed the trypsin from bovine or porcine origin. Porcine or bovine trypsin, when mixed with shrimp enzymes in pH‐stat assays in the presence of shrimp commercial feed, fish meal, or casein, there was added activity to hydrolyse the protein substrate. Hydrolysis of protein substrate was twofold to threefold stronger if exogenous enzymes were added. Results suggest that porcine or bovine trypsin could be used as feed supplements for whiteleg shrimp P. vannamei to enhance hydrolysis of proteins in feeds, because the commercial enzymes contributed to the hydrolysis of the protein in the three substrates in the presence of shrimp enzymes.  相似文献   

Cloning and sequencing of the ovine gamma-interferon gene   总被引：1，自引：0，他引：1  

AJ RADFORD  ALM HODGSON  JS ROTHEL  PR WOOD 《Australian veterinary journal》1991,68(3):82-84

Cytokines are major modulators of the immune system of all animals. The cloning and expression of recombinant cytokine genes have permitted the analysis of their immune function and role in the control of the immune response to disease and vaccination. While human, murine, and bovine genes have been cloned and sequenced, the cloning of ovine cytokine genes has not yet been reported. As sheep are of dominant economic importance to the Australian farming industry, it is of significance to clone and express these genes to facilitate the development of new and better vaccines and pharmaceuticals. We have initially selected ovine gamma-interferon (gamma-IFN) as a target cytokine gene. By the use of the polymerase chain reaction (PCR), using primers based on the bovine gamma-interferon sequence, we have amplified the ovine gamma-interferon gene from crude messenger RNA extracted from lymphocytes. After cloning and DNA sequencing the gene, we found that ovine gamma-IFN is 93% identical to bovine gamma-IFN in amino acid sequence. This result indicates that the PCR method will be a rapid and efficient means for cloning other ovine cytokine genes.  相似文献   

Effects of parasitism and of supplementing ewes with methyl methionine hydroxy analogue on the wool production of their lambs as adults     

JL WHEELER  AJ WILLIAMS  WH SOUTHCOTT 《Australian veterinary journal》1988,65(11):358-359

  相似文献   

Does Apoptosis Occur during Follicular Atresia in the Follicular Walls of the Porcine Ovary?     

K. Derecka  H. Kalamarz  AJ. Ziecik 《Reproduction in domestic animals》1995,30(1):32-35

Contents In this experiment, the possibility that the follicular-wall cells' death during ovarian follicular atresia occurs as a result of apoptosis was examined. Programmed cell death or apoptosis is a process whereby cells die in a controlled fashion, triggered by changes in levels of specific physiological stimuli. Morphological transformations of the cells are preceded by endo- nuclease-mediated genomic-DNA cleavage. The analysis of DNA from the theca and granulosa layers of follicles indicated that internucleosomal fragmentation of DNA occurred in atretic granulosa cells but not in atretic theca cells. The healthy granulosa and theca cells in all classes of follicles showed no apoptosis. This paper demonstrates that the death of porcine ovarian-follicle walls can be caused by different processes and, contrary to granulosa cells' apoptosis, either does not or only partly concerns the internal theca layer.  相似文献   

The isolation of salmonellas from piggery waste water after orthodox pondage treatment   总被引：2，自引：0，他引：2  

DP HENRY  AJ FROST  D. O'BOYLE  RDA CAMERON 《Australian veterinary journal》1995,72(12):478-479

  相似文献   

Histopathological changes in sheep experimentally infected with Babesia ovis   总被引：2，自引：0，他引：2  

M A Habela  D Reina  I Navarrete  E Redondo  S Hernández 《Veterinary parasitology》1991,38(1):1-12

Histopathological study was made of 12 Merino sheep - five splenectomized and seven intact - experimentally infected with Babesia ovis. Non-purulent encephalitis; initially exudative and subsequently interstitial pneumonia; pericarditis, myocarditis and haemorrhagic endocarditis; centrilobular necrotic hepatitis; hyperplasia of the lymphoreticular system; necrosis and vascular changes in adrenal glands were observed. The kidney was the most severely affected organ, exhibiting acute tubular necrosis typical of kidney shock syndrome. The lesions observed were suggestive of hypovolemic shock culminating in haemorrhagic diathesis owing to consumptive coagulopathy. Additionally, the massive release of catabolites from lysis and necrosis apparently produced endotoxic shock.  相似文献   

Recent developments in diagnosis of exotic disease at the Australian Animal Health Laboratory     

AJ FORMAN 《Australian veterinary journal》1993,70(5):161-163

  相似文献