SPRINKMOD – pressure and discharge simulation model for pressurized irrigation systems. 2. Case study     

C. de L. T. de Andrade  R. D. Wells  R. G. Allen 《Irrigation Science》1999,18(3):149-156

A computer model, SPRINKMOD, was tested with field data collected from a complex sprinkler irrigation system in operation. The original data collected were adjusted in order to calibrate the model for the irrigation system. Five modifications were made in the original data so that the model sensitivity could be evaluated. The model predicted the system operating point with less than 1% error, after some adjustments in the data. The relative mean standard error was 4.1% for the upstream pressure heads and 2.1% for the downstream pressure heads of all laterals analyzed together. Measurement of pressure and discharge at pump stations along with a reasonable estimate of leakage appears to be essential for simulation of old systems. Adjustments made to pipe wall thickness and pipe roughness were not as important as the adjustments made to the lateral valves closure in getting SPRINKMOD to simulate pressure heads that were close to the measured values. For long laterals, like center pivot laterals, a variable local loss coefficient for flow past a riser outlet worked better than a fixed value of 0.3. Received: 24 November 1997  相似文献   

Spatial variability in ocean‐mediated growth potential is linked to Chinook salmon survival     

Mark Henderson  Jerome Fiechter  David D. Huff  Brian K. Wells 《Fisheries Oceanography》2019,28(3):334-344

Early ocean survival of Chinook salmon, Oncorhynchus tshawytscha, varies greatly inter‐annually and may be the period during which later spawning abundance and fishery recruitment are set. Therefore, identifying environmental drivers related to early survival may inform better models for management and sustainability of salmon in a variable environment. With this in mind, our main objectives were to (a) identify regions of high temporal variability in growth potential over a 23‐year time series, (b) determine whether the spatial distribution of growth potential was correlated with observed oceanographic conditions, and (c) determine whether these spatial patterns in growth potential could be used to estimate juvenile salmon survival. We applied this method to the fall run of the Central Valley Chinook salmon population, focusing on the spring and summer period after emigration into central California coastal waters. For the period from 1988 to 2010, juvenile salmon growth potential on the central California continental shelf was described by three spatial patterns. These three patterns were most correlated with upwelling, detrended sea level anomalies, and the strength of onshore/offshore currents, respectively. Using the annual strength of these three patterns, as well as the overall growth potential throughout central California coastal waters, in a generalized linear model we explained 82% of the variation in juvenile salmon survival estimates. We attributed the relationship between growth potential and survival to variability in environmental conditions experienced by juvenile salmon during their first year at sea, as well as potential shifts in predation pressure following out‐migration into coastal waters.  相似文献   

Low stress response exhibited by juvenile yellowtail kingfish (Seriola lalandi Valenciennes) exposed to hypercapnic conditions associated with transportation     

Damian Moran  Rufus M G Wells  Stephen J Pether 《Aquaculture Research》2008,39(13):1399-1407

Transportation of yellowtail kingfish (Seriola lalandi Valenciennes) juveniles from hatchery to on‐growing operations in New Zealand exposes the fish to significantly elevated carbon dioxide (CO₂) concentrations. Experiments were undertaken to assess metabolic and haematological stress responses after a 5‐h period of hypercapnia, followed by recovery in normocapnia. Mortality was low (0.5%) and secondary stress indices (blood glucose, blood lactate, muscle pH and muscle lactate) remained largely unchanged during a simulated transportation and recovery, despite juveniles being exposed to CO₂ concentrations as high as 75 mg CO₂ L^?1 (38 mm Hg partial pressure). There was some haematological disturbance midway through simulated transports, where water was maintained at fixed CO₂ concentrations of 8 and 50 mg CO₂ L^?1 (4 and 26 mm Hg respectively). Persistent erythrocyte swelling continued during transport at 50 mg CO₂ L^?1, whereas at 8 mg CO₂ L^?1, haematological variables had returned to control levels. There was no mortality recorded for any of the treatments, and haematological variables were restored to pre‐manipulation levels after 31 h. The results indicated that juvenile yellowtail kingfish have a robust physiology and can cope with the stressors imposed by acute exposure to moderate to high levels of CO₂ associated with live transport.  相似文献   

Efficacy of porcine parvovirus vaccines   总被引：2，自引：0，他引：2  

K R Edwards  M A Emmerson  P R Luff  D E Wells  J C Muskett  A E Wrathall  C Richardson  B N Parker  D H Thornton 《The Veterinary record》1986,119(9):203-206

Three inactivated porcine parvovirus vaccines were tested for efficacy in 66 susceptible gilts. The gilts were challenged with virulent virus on the 40th day of gestation. All the vaccines provided excellent protection against fetal mortality despite insignificant serological responses to one of them. Good protection was obtained with two of the vaccines even when the dose was substantially reduced. Unvaccinated controls had very few viable fetuses.  相似文献   

Lability of sorbitol dehydrogenase in refrigerated and frozen horse serum     

K. Sherman DVM  R. Wells DVM  M. Mattiacci MS   《Journal of Equine Veterinary Science》1991,11(3)

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Bovine spongiform encephalopathy: detection and quantitation of fibrils, fibril protein (PrP) and vacuolation in brain     

A C Scott  G A Wells  M J Stack  H White  M Dawson 《Veterinary microbiology》1990,23(1-4):295-304

Bovine spongiform encephalopathy (BSE) is a new disease of cattle which has considerable homology with scrapie, the archetype of the transmissible spongiform encephalopathies. Abnormal brain fibrils, called scrapie associated fibrils (SAF), are specific ultrastructural markers for these diseases. Fibril detection was compared with histopathological diagnosis in the brains of 167 cattle; 157 clinically suspect BSE and 10 clinically normal. Fibrils were detected in samples of pooled brain regions of 67/144 in which vacuolar changes of BSE were confirmed, but absent in the remaining 23 brains, in which no vacuolation was found, including those from the clinically normal cattle and 13 with alternative neuropathological diagnoses. When eight defined anatomic regions from the brains of another 22 affected cows were examined, the sensitivity of fibril detection was greater than 90% for the brain stem areas. Fibril prevalence in these areas approximated to severity of vacuolar changes. When the same defined regions from four of the affected cows were assayed for fibril protein (PrP) by western blotting, the density of immuno-labelling generally correlated with the fibril prevalence. This study confirms the specificity of fibril detection for BSE, shows that the ease of fibril detection depends on anatomic region sampled and suggests an association between PrP accumulation and vacuolar changes in certain neuroanatomic areas.  相似文献   

Clinical usefulness of intradermal fluorescein and patent blue violet dyes for sentinel lymph node identification in dogs   总被引：1，自引：0，他引：1  

S. Wells  A. Bennett  P. Walsh  S. Owens  J. Peauroi 《Veterinary and comparative oncology》2006,4(2):114-122

The first lymph node receiving drainage from a specific anatomic region is referred to as the sentinel lymph node (SLN). This study sought to evaluate the intradermal use of two dyes, patent blue violet (PBV) and fluorescein (FL), for SLN mapping in the dog. Multiple intradermal injections were performed in five healthy dogs using two dyes, PBV in 0.9% NaCl and FL in solutions of 0.9% NaCl and 6% hetastarch. Skin flaps were raised and followed to the first area of discrete stain uptake. Areas of uptake were identified as lymph nodes grossly and by cytology. Identification of a SLN for each area of intradermal injection was accomplished for 98% of the injection sites. Intradermal injections of both PBV and FL dyes produce readily visible staining of lymphatic vessels and SLNs in healthy dogs and are sufficient to allow ready identification of these structures during postmortem dissection.  相似文献   

Photochemistry of some systemic pyrimidine fungicides     

Clifford H. J. Wells  Stephen J. Pollard  Devdoot Sen 《Pest management science》1979,10(2):171-176

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A survey of cattle health problems in the eastern plains of Colombia     

D E Corrier  J M Cortés  E R Aycardi  E A Wells  M Bohorquez  J J Salazar 《The British veterinary journal》1978,134(2):101-107

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Stochastic variation of system component variables in a network analysis     

R.L. Bingner  T.C. Bridges  L.G. Wells  Y. Miyake  G.A. Duncan 《Agricultural Systems》1981,7(3):179-188

A deterministic network simulation was reformulated to include the uncertainty of various parameters. Then, by the recording values obtained for each pathway or system in the network for a set of stochastic parameters and then choosing another set of stochastic parameters and recording the values obtained from that simulation, an average value and standard deviation for any system in the network can be determined. In the decision-making process of choosing from one system over another, the manager will have a better understanding of the complex interactions involved by knowing the effects that uncertainty in the system can cause.  相似文献