Control of phosphorus inputs to a freshwater lake: a case study     

M W Marsden  I R Fozzard  D Clark  N McLean  M R Smith 《Aquaculture Research》1995,26(8):527-538

The legislation permitting control of phosphorus inputs into the aquatic environment From point and diffuse sources is complex and incomplete. River Purification Authorities in Scotland are responsible for the implementation of this legislation, and additionally, have adopted policies aimed at protecting waters from the effects of eutrophication. This paper describes the implementation of the legislation and the policies adopted by the Forth River Purification Board for the control of freshwater eutrophication by reference to the Lake of Menteith. in Central Scotland. The Lake of Menteith is described, the results of a detailed monitoring exercise are presented and the control measures applied are discussed. The Lake of Menteith is classified as mesotrophic. it has a high conservation and amenity value, and is operated as a commercial sport fishery by the Lake of Menteith Fishery Company. The Company operate a fish cage rearing unit on the Lake and two land-based rearing units on tributary streams. The phosphorus budget for the Lake is described and the implications for future controls discussed.  相似文献   

Suspected fatal venous air embolism during anaesthesia in a Pomeranian dog with pulmonary calcification     

VP Walsh  RG Machon  JS Munday  CJ Broome 《New Zealand veterinary journal》2013,61(5):359-362

CASE HISTORY: Death occurred in a 1.25 kg, 9-month-old female Pomeranian dog undergoing anaesthesia for surgical repair of partially healed fractures of the radius and ulna.

CLINICAL FINDINGS: Following sedation, anaesthesia was induced using thiopentone and maintained with halothane in oxygen. An acute decrease in the dog's end-tidal carbon dioxide (EtCO₂) measurements was noted approximately 50 min after induction, immediately following delivery of a 5-ml bolus of lactated Ringer's solution (LRS) administered to flush a small (0.06 ml) volume of fentanyl via a pre-placed intravenous (I/V) catheter. Venous air embolism (VAE) was suspected and the dog died despite interventive therapy. On post-mortem examination, several air bubbles were noted when the right ventricle was opened under water. Histologically, the kidneys appeared abnormal with immature glomeruli, and the lungs appeared diffusely mineralised. The origin of the air was probably small bubbles and microbubbles that may have been present in the extension set and 20 ml syringe used for the administration of fentanyl and I/V fluids to the dog.

DIAGNOSIS: Renal dysplasia and diffuse pulmonary calcification, with VAE as the probable cause of death.

CLINICAL RELEVANCE: In this case of VAE-associated anaesthetic death, it is further speculated that underlying pulmonary disease, in the form of pulmonary calcification, may have contributed to an increased sensitivity to the adverse effects of VAE.  相似文献   

Emerging technologies for identifying superior dairy cows in New Zealand     

DJ Garrick  RG Snell 《New Zealand veterinary journal》2013,61(6):390-399

The performance of animals is determined by the interaction of their genes with environmental circumstances. Accordingly, animals exhibiting superior performance are not necessarily the animals with the best genes nor are they the best choice of parents. Statistical analyses of production records for repeated traits, e.g. lactation yields and reproductive performance, show that part of the variation in performance among animals in the same herd and year is due to genetic differences, and the remainder is due to so-called residual or environmental factors that are not passed on to offspring. These within-herd environmental factors can be partitioned into a component that affects performance throughout an animal's lifetime, and a part that is unique to each observation. The process of animal evaluation from pedigree and performance records partitions the superiority of each cow into these three components. Reliable assessment of the genetic merit of bulls has required progeny testing, and for cows has required observation of their own individual performance. Selection on the genetic or breeding value component has systematically improved animal performance over recent decades, but has been limited by the age at which assessments of genetic merit are available.

Emerging molecular technologies can read DNA sequences or measure RNA expression and have allowed the identification of a number of chromosome regions, and a few specific genes in those regions, that influence economic performance. This information allows better characterisation of the relationships between animals and more accurate predictions of genetic merit in bulls without progeny information and in cows that have yet to produce their own performance record. At some stage, enough genes responsible for variation in performance will be identified to allow faster genetic progress through selection of animals at young ages and therefore more rapid turnover of the generations. Mechanisms that modify gene expression have been identified and these may ultimately allow animals to be selected at an early age for lifetime productivity, accounting for processes that modify gene expression and lead to differences in performance that are not reflected by DNA sequence information. This review describes the status of these emerging technologies and their likely role in the improvement of dairy cattle.  相似文献   

Abortions in sheep caused by Salmonella Brandenburg: Pathological findings     

RG Clark  JM Gill  RA Fairley  JA Smart 《New Zealand veterinary journal》2013,61(6):356-357

CASE HISTORY: A 7-year-old cat developed sporadic vomiting, reduced appetite, and weight loss over the previous 3 months.

CLINICAL FINDINGS: Palpation revealed a large mid-abdominal mass and the cat had marked eosinophilia. The cat progressively lost weight over the next 7 weeks when euthanasia was performed.

PATHOLOGICAL FINDINGS: Necropsy revealed a 3?cm diameter firm white intramural mass in the colon and another in the pylorus. Mesenteric and cranial mediastinal lymph nodes were firm, pale, and enlarged. Histopathological examination revealed foci of necrosis surrounded by thick dense collagen trabeculae and predominantly eosinophilic inflammation within the intestine and lymph nodes. Marked eosinophilic infiltration of the liver was also present.

DIAGNOSIS: The lesions were consistent with gastrointestinal eosinophilic sclerosing fibroplasia (FGESF).

CLINICAL RELEVANCE: This is the first report of FGESF in a New Zealand cat and the first time lesions of FGESF have been observed in extra-abdominal tissues. Intestinal neoplasia can be clinically identical to FGESF and histopathology is required for differentiation. Evidence suggests that FGESF has a more favourable prognosis than intestinal neoplasia.  相似文献   

Salmonella Brandenburg — emergence of a variant strain on a sheep farm in the South Island of New Zealand     

RG Clark  S Swanney  CM Nicol  M Leyland  SG Fenwick 《New Zealand veterinary journal》2013,61(3):146-147

AIM: To compare the rectal and I/V administration of tramadol in dogs, to assess both its pharmacokinetic properties and absolute bioavailability.

METHODS: After rectal administration via suppositories and I/V injection of tramadol (4 mg/kg), the concentration of tramadol and its main metabolites, O-desmethyl-tramadol (M1), N-desmethyl-tramadol (M2) and N,O-didesmethyl-tramadol (M5), were determined in plasma, using high-performance liquid chromatography (HPLC). A balanced cross-over study was used, involving six male Beagle dogs.

RESULTS: Plasma concentrations after rectal and I/V administration were fitted on the basis of mono- and bi-compartmental models, respectively. Following rectal administration tramadol was detected from 5 minutes up to 10 hours, in lesser amounts than M5 and M2, while M1 was detected in negligible amounts. Following I/V administration tramadol was detected up to 10 hours, M2 and M5 were detected at similar concentrations, and M1 was present at low concentrations. The area under the curve (AUC) of the three metabolites did not differ significantly after either route of administration of tramadol. The absolute bioavailability of tramadol via rectal administration was 10 (SD 4)%.

CONCLUSIONS: After rectal administration of tramadol suppositories, absorption of the active ingredient was rapid, but its metabolism quickly transformed the parent drug to high levels of M2 and M5.

CLINICAL RELEVANCE: In the dog, rectal pharmaceutical formulation of tramadol would have a different pharmacokinetic behaviour than in humans.  相似文献   

Stand-level patterns of carbon fluxes and partitioning in a Eucalyptus grandis plantation across a gradient of productivity, in Sao Paulo State, Brazil     

Campoe OC  Stape JL  Laclau JP  Marsden C  Nouvellon Y 《Tree physiology》2012,32(6):696-706

Wood production represents a large but variable fraction of gross primary production (GPP) in highly productive Eucalyptus plantations. Assessing patterns of carbon (C) partitioning (C flux as a fraction of GPP) between above- and belowground components is essential to understand mechanisms driving the C budget of these plantations. Better knowledge of fluxes and partitioning to woody and non-woody tissues in response to site characteristics and resource availability could provide opportunities to increase forest productivity. Our study aimed at investigating how C allocation varied within one apparently homogeneous 90 ha stand of Eucalyptus grandis (W. Hill ex Maiden) in Southeastern Brazil. We assessed annual above-ground net primary production (ANPP: stem, leaf, and branch production) and total belowground C flux (TBCF: the sum of root production and respiration and mycorrhizal production and respiration), GPP (computed as the sum of ANPP, TBCF and estimated aboveground respiration) on 12 plots representing the gradient of productivity found within the stand. The spatial heterogeneity of topography and associated soil attributes across the stand likely explained this fertility gradient. Component fluxes of GPP and C partitioning were found to vary among plots. Stem NPP ranged from 554 g C m(-2) year(-1) on the plot with lowest GPP to 923 g C m(-2) year(-1) on the plot with highest GPP. Total belowground carbon flux ranged from 497 to 1235 g C m(-2) year(-1) and showed no relationship with ANPP or GPP. Carbon partitioning to stem NPP increased from 0.19 to 0.23, showing a positive trend of increase with GPP (R(2) = 0.29, P = 0.07). Variations in stem wood production across the gradient of productivity observed at our experimental site were a result of the variability in C partitioning to different forest system components.  相似文献   

Providencia rettgeri meningitis in hatchling saltwater crocodiles (Crocodylus porosus)     

PW LADDS  J. BRADLEY  RG HIRST 《Australian veterinary journal》1996,74(5):397-398

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Metabolism of carbosulfan [2,3-dihydro-2,2-dimethylbenzofuran-7-yl (di-n-butylaminothio)methylcarbamate] in the rat and house fly     

Paul J. Marsden  Eichi Kuwano  T.Roy Fukuto 《Pesticide biochemistry and physiology》1982,18(1):38-48

The metabolism of carbosulfan, 2,3-dihydro-2,2-dimethylbenzofuran-7-yl (di-n-butylaminothio)-methylcarbamate, was studied in the rat and house fly. Carbosulfan was metabolized via at least two major pathways in the rat, by initial oxidation of the sulfur atom and by NS bond cleavage. The principal rat metabolites were the conjugated keto-phenol from the ring-labeled carbo-sulfan, carbon dioxide from the carbonyl-labeled carbosulfan, and dibutylamine from the dibutylamino-labeled carbosulfan. In house flies, carbosulfan was converted primarily into carbofuran and related oxidation products. The lower mammalian toxicity of carbosulfan compared to its insecticidal activity is explained on the basis of differences in routes and rates of metabolism of carbosulfan in mammals and insects.  相似文献   

Presumed hereditary elliptocytosis in a dog     

Mills JN  Marsden CA 《Australian veterinary journal》1999,77(10):651-652

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Application of nonlinear programming to water quality control     

James R. Marsden  David E. Pingry  Andrew Whinston 《Water, air, and soil pollution》1973,2(2):155-169

Planning the design of an efficient waste treatment system can be aided through the use of mathematical models and optimization theory. This paper attempts to illustrate this point of view by formulating a model and applying it to a specific river basin. While the models give useful insights, questions still remain concerning limitations inherent in the models. We present some comments on this point and suggestions for resolving some of the resulting economic questions.  相似文献