Interactions between weeds of winter wheat under different fertilizer,cultivation and weed management treatments     

McCLOSKEY  FIRBANK  WATKINSON  WEBB 《Weed Research》1998,38(1):11-24

Interactions between the weeds Bromussterilis L., Galium aparine L. and Papaver rhoeas L. were investigated over 3 years of continuous winter wheat (Triticum aestivum L.) across a factorial combination of organic and conventional fertilizer, and ploughing and hand-roguing contrasted with minimum tillage and herbicide. The species were sown separately and together at 50 seeds m^?2 per species at the start of the experiment in October 1989. In addition, there were weed-free and background-weed controls. Weed densities were monitored at roughly monthly intervals and crop yield recorded for three seasons. B. sterilis populations increased 10-fold under minimum tillage, but declined under ploughing. Densities of P. rhoeas remained largely low. G. aparine increased on the organically fertilized minimum-tillage plots, except where B. sterilis was present; the high densities of B. sterilis reduced the population size of G. aparine. Crop yield was influenced most strongly by the fertilizer treatment in the first season, but later the density of B. sterilis was by far the most important factor; the evidence of interactive effects of the different weed species on crop yield was weak at best. Interactive effects of arable weed species can be observed, but only at very high densities, and so are unlikely to be of widespread economic importance.  相似文献   

A severity score for spontaneous canine acute pancreatitis     

CG RUAUX  RB ATWELL 《Australian veterinary journal》1998,76(12):804-808

Objective To derive a severity score for spontaneous canine acute pancreatitis applicable to general practice.
Design Cohort study of canine pancreatitis cases.
Procedure Cases (n = 68) of spontaneous canine acute pancreatitis presented to general practitioners were identified among accessions to Veterinary Pathology Services Brisbane. The primary veterinarian was surveyed by telephone to ascertain the outcome of each case. Scores were assigned for extent of hyperamylasaemia, hyperlipasaemia and number of organ systems other than the pancreas compromised. The probability of mortality with each score of each analyte was calculated. The strength of interaction between scores for each analyte and mortality rate was assessed by chi-square analysis where appropriate. Relationships between the organ system score, other physiological variables and likelihood of euthanasia were analysed.
Results Scores derived mathematically from analysis of enzyme activities had poor abilities to predict mortality. The score based upon the number of organ systems compromised showed good ability to predict mortality and the interaction between the organ system score and mortality rate was significant by chi-square analysis (P < 0.01). Distribution of data within the amylase and lipase scores was not compatible with chi-square analysis.
Conclusion Assessment of severity of spontaneous canine acute pancreatitis using pancreatic enzyme activities is potentially inaccurate. The use of a severity score based upon organ system compromise was more accurate in determining the likelihood of mortality in spontaneous canine acute pancreatitis. This is compatible with the hypothesis that severe canine acute pancreatitis is a multiple organ failure syndrome.  相似文献   

Coprological methods for the diagnosis of Anoplocephala perfoliata infection of the horse     

RMC WILLIAMSON  I. BEVERIDGE  RB GASSER 《Australian veterinary journal》1998,76(9):618-621

Objective To compare the sensitivities of three coprological techniques for the diagnosis of Anoplocephala perfoliata infection in horses and to assess the value of the methods for diagnosis of horses at risk of clinical cestodiasis.
Design Faecal samples were collected from necropsied horses with or without A perfoliata infection and examined using one sedimentation and two different flotation methods. The coprological results were compared with worm counts performed at necropsy of the horses and the degree of mucosal damage. In addition, the efficiency of recovery of A perfoliata eggs from faeces was tested.
Results The overall sensitivities of the methods ranged from 22.5 to 37.5%, and the capacity of the methods to diagnose infection increased with the intensity of infection. A simple flotation method achieved a better sensitivity (37.5%) at all intensities of infection compared with the other two methods (22.5 to 25%). That method was also more sensitive in detecting eggs in 'negative' faecal samples spiked with known numbers of A perfoliata eggs.
Conclusion The results indicated that, despite the low sensitivities of present methods, faecal flotation is likely to be of value in detecting horses at risk of clinical disease.  相似文献   

Transcriptomic investigation of the molecular mechanisms underlying resistance to the neonicotinoid thiamethoxam and the pyrethroid lambda-cyhalothrin in Euschistus heros (Hemiptera: Pentatomidae)     

Ewerton C Lira  Antonio RB Nascimento  Chris Bass  Celso Omoto  Fernando L Cônsoli 《Pest management science》2023,79(12):5349-5361

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Comparison of two methods of seminal plasma removal on buffalo (Bubalus bubalis) sperm cryopreservation          下载免费PDF全文

RS Albuquerque  R Morais  AN Reis  MS Miranda  EAR Dias  FM Monteiro  CCP Paz  M Nichi  GKV Kawai  CPF Della'Aqua  FO Papa  RB Viana  LU Gimenes 《Reproduction in domestic animals》2017,52(5):905-910

Cryopreservation causes damage to spermatozoa, and methods minimizing this damage are therefore needed. Although much discussed, seminal plasma removal has become an alternative to improve sperm quality and viability after freezing and has been applied to different species in attempt to obtain good results. The objective of this study was to evaluate semen quality in buffaloes submitted to two methods for seminal plasma removal (filtration and centrifugation). Semen samples were collected from seven Murrah buffalo bulls (Bubalus bubalis) once a week for 8 weeks. Each ejaculate was divided into three groups: control (presence of seminal plasma), centrifugation and filtration. Sperm kinetics was evaluated with the computer‐assisted sperm analysis (CASA) system. Plasmalemma and acrosomal membrane integrity, mitochondrial membrane potential and reactive oxygen species (ROS) were measured by flow cytometry, and lipid peroxidation was evaluated by the thiobarbituric acid reactive substances (TBARS) assay. Seminal plasma removal did not improve sperm kinetics compared to the control group. Centrifugation increased the number of cells with damaged acrosomal membranes (0.77 ± 0.05) and filtration caused greater plasmalemma and acrosomal membrane damage (22.18 ± 1.07). No difference in the mitochondrial membrane potential was observed between groups. In contrast, ROS production was higher in the centrifugation group compared to the control and filtration groups, although no differences in TBARS formation were detected. In conclusion, seminal plasma removal did not improve the quality of thawed buffalo semen compared to control in terms of sperm kinetics, membrane integrity, mitochondrial membrane potential or lipid peroxidation.  相似文献   

Effects of dietary starches and the protein to energy ratio on growth and feed efficiency of juvenile cobia,Rachycentron canadum     

K.A. JR WEBB  L.T. RAWLINSON  G.J. HOLT 《Aquaculture Nutrition》2010,16(5):447-456

Optimization of the protein to energy ratio in juvenile cobia (Rachycentron canadum) would allow the production of diets that maximize growth without the addition of excess energy that may increase costs or even be detrimental to the health of the fish. During a 6‐week growth trial, juvenile cobia (5.6 ± 0.5 g fish^?1 initial weight) were fed five isonitrogenous and isolipidic diets containing various protein to energy ratios using starch as the energy source. At the end of the trial, some fish were analysed for body composition characteristics while the rest were used to examine the excretion of dietary starch in the feces. Survival and growth were not significantly affected, but feed efficiency (ranging from 0.64 to 0.94) and daily consumption (ranging from 45.3 to 64.1 g kg^?1 of body weight d^?1) were affected. No reduction in consumption due to excess energy was noted. Analysis of the fecal carbohydrate data showed a linear relationship between dietary inclusion and excretion of carbohydrates with no sign of reaching saturation. Results of this study suggest that cobia can utilize dietary carbohydrates up to at least 340 g kg^?1 of dry diet with an optimal protein to energy ratio of approximately 34 mg protein kJ^?1metabolizable energy.  相似文献   

Turbulent transport reduction by zonal flows: massively parallel simulations   总被引：2，自引：0，他引：2  

Z Lin  TS Hahm  WW Lee  WM Tang  RB White 《Science (New York, N.Y.)》1998,281(5384):1835-1837

Three-dimensional gyrokinetic simulations of microturbulence in magnetically confined toroidal plasmas with massively parallel computers showed that, with linear flow damping, an asymptotic residual flow develops in agreement with analytic calculations. Nonlinear global simulations of instabilities driven by temperature gradients in the ion component of the plasma support the view that turbulence-driven fluctuating zonal flows can substantially reduce turbulent transport. Finally, the outstanding differences in the flow dynamics observed in global and local simulations are found to be due to profile variations.  相似文献   

Transferrin receptor expression in serum exosomes as a marker of regenerative anaemia in the horse          下载免费PDF全文

E. D. Rout  T. L. WEBB  H. M. Laurence  L. Long  C. S. Olver 《Equine veterinary journal》2015,47(1):101-106

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Principles for the use of macrocyclic lactones to minimise selection for resistance     

RJ DOBSON  RB BESIER  EH BARNES  SCJ LOVE  A VIZARD  K BELL  LF Le  JAMBRE 《Australian veterinary journal》2001,79(11):756-761

OBJECTIVE: To provide principles for the appropriate use of avermectin/milbemycin or macrocyclic lactone (ML) anthelmintics in sheep, to ensure effective worm control and to minimise selection for ML resistance. STRATEGY: The principles were based on an assessment of the information currently available. The MLs were categorised into three groups (ivermectin [IVM], abamectin [ABA] and moxidectin [MOX]) based on structural differences, persistence and efficacy against ML resistant strains. The reported order of activity or efficacy against ML resistant worm strains was IVM相似文献   

Anthelmintic dose selection by farmers   总被引：1，自引：0，他引：1  

RB BESIER  DL HOPKINS 《Australian veterinary journal》1988,65(6):193-194

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