Superheavy elements: a crossroads     

Seaborg GT  Loveland W  Morrissey DJ 《Science (New York, N.Y.)》1979,203(4382):711-717

The failure to synthesize superheavy elements by using complete fusion reactions is most likely understandable in terms of the low survival probabilities of the superheavy precursors formed in these reactions or (in some cases) the failure to achieve complete fusion. Further attempts to synthesize these elements by using complete fusion or deep inelastic transfer reactions, or both, are discussed in light of these results.  相似文献   

Drivers,challenges and opportunities of forage technology adoption by smallholder cattle households in Cambodia     

K Ashley  S Wilson  JR Young  HP Chan  S Vitou  S Suon  PA Windsor  RD Bush 《Tropical animal health and production》2018,50(1):63-73

Forage technology has been successfully introduced into smallholder cattle systems in Cambodia as an alternative feed source to the traditional rice straw and native pastures, improving animal nutrition and reducing labour requirements of feeding cattle. Previous research has highlighted the positive impacts of forage technology including improved growth rates of cattle and household time savings. However, further research is required to understand the drivers, challenges and opportunities of forage technology for smallholder cattle households in Cambodia to facilitate widespread adoption and identify areas for further improvement. A survey of forage-growing households (n = 40) in July–September 2016 examined forage technology adoption experiences, including reasons for forage establishment, use of inputs and labour requirements of forage plot maintenance and use of forages (feeding, fattening, sale of grass or seedlings and silage). Time savings was reported as the main driver of forage adoption with household members spending approximately 1 h per day maintaining forages and feeding it to cattle. Water availability was reported as the main challenge to this activity. A small number of households also reported lack of labour, lack of fencing, competition from natural grasses, cost of irrigation and lack of experience as challenges to forage growing. Cattle fattening and sale of cut forage grass and seedlings was not found to be a widespread activity by interviewed households, with 25 and 10% of households reporting use of forages for these activities, respectively. Currently, opportunities exist for these households to better utilise forages through expansion of forage plots and cattle activities, although assistance is required to support these households in addressing current constraints, particularly availability of water, if the sustainability of this feed technology for smallholder cattle household is to be established in Cambodia.  相似文献   

Leptin, GH, PRL, Insulin and Metabolic Parameters Throughout the Dry Period and Lactation in Dairy Cows     

PA Accorsi  N Govoni  R Gaiani  C Pezzi  E Seren  C Tamanini 《Reproduction in domestic animals》2005,40(3):217-223

Leptin may play a role in the endocrine-metabolic processes that guarantee the physiological course of lactation in dairy cattle. This study was aimed at determining the changes in plasma concentrations of leptin and some of the main hormones and metabolites involved in the lactogenetic process in high-yielding dairy cows throughout lactation; we also wanted to assess whether leptin secretion is subjected to seasonal influences. Blood samples were collected from 23 Italian Friesian dairy cows from the end of a lactation to the ninth month of the subsequent one; in addition, blood was sampled from 47 dairy cows in different phases of lactation during February and July. Plasma concentrations of leptin, growth hormone (GH), insulin, prolactin (PRL), glucose, non-esterified fatty acids (NEFA) and urea were quantified by either validated radioimmunoassay (RIA) or enzymatic colorimetric methods. At the beginning of lactation, GH concentrations significantly increased, while a significant reduction occurred in leptin and insulin. This endocrine condition, such as the significant increase in NEFA plasma concentrations, is indicative of a marked lipid mobilization. In the more advanced stages of lactation, when both energy and protein balances become positive, leptin plasma concentrations increased, whereas GH and NEFA concentrations declined. During the summer months, a significant increase in leptin plasma concentrations, irrespective of the phase of lactation, was observed. Collectively, our findings suggest that, in dairy cows, leptin may represent a 'metabolic signal' of animal's status of fattening and nutritional level; in addition, leptin seems to be influenced by photoperiod and environmental temperature.  相似文献   

Hepatic vasculopathy and encephalopathy in Brahman-type calves     

PA GILL  WL TOWNSEND 《Australian veterinary journal》1993,70(2):69-69

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In vitro interaction of some drug combinations to inhibit rapidly growing mycobacteria isolates from cats and dogs and these isolates' susceptibility to cefovecin and clofazimine          下载免费PDF全文

CJM Bennie  JLK To  PA Martin  M Govendir 《Australian veterinary journal》2015,93(1-2):40-45

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Balloon occlusion of the caudal vena cava for vascular contrast studies as an aid to intravascular coil embolisation for the treatment of intrahepatic portosystemic shunts in three dogs          下载免费PDF全文

DA Cook  BJ Gavaghan  PA Moses 《Australian veterinary journal》2015,93(12):452-459

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Assessment of the potential relationship between egg quality and infectious bronchitis virus infection in Australian layer flocks     

KA Hewson  T Robertson  PA Steer  JM Devlin  AH Noormohammadi  J Ignjatovic 《Australian veterinary journal》2014,92(4):132-138

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Chitinase production by an Arthrobacter sp. lysing cells of Fusarium roseum     

R.F. Morrissey  E.P. Dugan  J.S. Koths 《Soil biology & biochemistry》1976,8(1):23-28

An Arthrobacter sp. which actively lysed Fusarium roseum was found to liberate chitinase (E.C. 3.2-1.14, chitin glycanohydrolase), an enzyme essential for the hydrolysis of chitin, a major component of fusarial hyphal walls. Factors involved in the production of chitinase were investigated by modifying culture conditions and assaying for enzyme activity. Production occurred on colloidal chitin as well as on native chitin supplemented with yeast extract or peptone. Enzyme production paralleled growth; liberation of enzyme took place during the log phase with the maximum yield being obtained at the stationary phase. Addition of the non-ionic surfactant, polyoxyethylene sorbitan monooleate (Tween 80) increased enzyme yield. An inverse relationship was found between the amount of enzyme produced and the quantity of n-acetyl-glucosamine liberated. The enzyme was generally not produced when grown on various other carbohydrates. These findings suggest that chitinase is inducible and that chitin breakdown is regulated by a repressor-inducer mechanism.Initial hydrolysis rates of colloidal chitin were proportional to the concentration of chitinase used. Optimal pH and temperature for enzyme activity were 4.9 and 50°C, respectively. Purification of the chitinase was obtained by (NH₄)₂SO₄ precipitation followed by DEAE-cellulose and Sephadex chromatography, achieving a 12-fold increase in specific activity.  相似文献   

Cross-protective immunity and the serological classification system for Bacteroides nodosus     

DJ STEWART  JA VAUGHAN  TC ELLEMAN†  PA HOYNE†  KJ BURNS  JH DUFTY 《Australian veterinary journal》1991,68(2):50-53

The relationship between the serological classification system for serogroup B and for serogroup H of Bacteroides nodosus and cross-protection between subgroups within these serogroups was examined. Protection against ovine footrot following vaccination was achieved against other subgroup strains provided sufficient cross-reactive antibody was induced by shared pilus antigens. Within serogroup B, better cross-protection against one subgroup was obtained with a pili vaccine than a whole cell vaccine which correlated with higher pilus antibody titres induced by the former. For serogroup H, a lack of cross-protection and serological reactivity between subgroups was demonstrated, which indicates that the prototype strain of subgroup H2 should be designated a new serogroup.  相似文献   

Influence of dietary alpha-tocopherol on tocopherol concentrations in chick tissues     

P J Sheehy  P A Morrissey  A Flynn 《British poultry science》1991,32(2):391-397

1. The effect of feeding alpha-tocopherol (5 to 180 micrograms/g diet) for 24 days on the concentrations of alpha-tocopherol in various chicken tissues was investigated. 2. Tissue alpha-tocopherol concentrations responded to dietary intake in the order: heart congruent to lung greater than liver greater than thigh muscle greater than brain, and in all cases the relationship between the concentrations of dietary and tissue alpha-tocopherol was highly significant (0.997 less than or equal to r less than or equal to 1). 3. Plasma alpha-tocopherol concentration appears to be a good index (r greater than or equal to 0.910, P less than 0.001) of alpha-tocopherol status of lung, liver and heart.  相似文献