Atrial Fibrillation Associated with Anesthesia in a Standardbred Gelding     

JOHN A. E. HUBBELL dvm  ms  Diplomateacva  WILLIAM W. MUIR dvm  PhD  Diplomateacva RICHARD M. BEDNARSKI dvm  ms  Diplomateacva 《Veterinary surgery : VS》1986,15(6):450-452

A Standardbred gelding was anesthetized on three occasions over a 3 year period. Anesthesia was induced with xylazine and thiamylal on the first occasion, with xylazine, guaifenesin, and thiamylal on the second, and with acepromazine, guaifenesin, and ketamine on the third. Anesthesia was maintained with halothane during each episode. The horse had atrial fibrillation (AF) after induction of anesthesia on the first two occasions. Because arterial blood pressure remained within normal limits during AF and anesthesia, conversion to normal sinus rhythm with quinidine was not attempted. Reversion to normal sinus rhythm occurred within 12 hours of recovery after each of the first two anesthetic episodes. The gelding remained in normal sinus rhythm throughout the third anesthetic period and recovered uneventfully. Potential causes for AF in anesthetized horses are discussed.  相似文献   

Tree growth and stand development of four Populus clones in large monoclonal plots     

DEBELL  DEAN S.  HARRINGTON  CONSTANCE A.  CLENDENEN  GARY W.  ZASADA  JOHN C. 《New Forests》1997,14(1):1-18

Four clones of Populus were planted in replicated monoclonal plots near Olympia, WA, to evaluate their suitability for use in short-rotation culture. All clones were easily established and had minimal problems from damaging agents during the first five years. Observed differences among clones in pattern and amount of growth appeared to be associated with differences in number and density of buds, sylleptic branching, and phenology. In addition, differences in drought tolerance and stockability may also have influenced clonal differences in annual growth and stand productivity. Individual tree growth was limited by the dense 1.0-m spacing, but the best-growing clones averaged 13 to 16 m tall, 7 to 9 cm in breast-high diameter (1.3 m), and produced stand basal areas exceeding 38 m²ha^-1at 8 years. Mortality was negligible for 7 years, after which various combined effects of competition, stem borer damage (Cryptorhyncus lapathi), and a severe windstorm caused mortality ranging from 18 to 36% in the three fastest growing clones.  相似文献   

Influences of mean advection and simple behavior on the distribution of cod and haddock early life stages on Georges Bank   总被引：2，自引：0，他引：2  

FRANCISCO E. WERNER  FRED H. PAGE  DANIEL R. LYNCH  JOHN W. LODER  R. GREGORY LOUGH  R. IAN PERRY  DAVID A. GREENBERG  MICHAEL M. SINCLAIR 《Fisheries Oceanography》1993,2(2):43-64

Results of a modeling study designed to explore the influences of physical advection and certain biological mechanisms on the distribution of cod (Gadus morhua) and haddock (Melarwgrammus aeglefinus) early life stages on Georges Bank are described. Using a late-winter/early-spring 3-D circulation field driven by the M₂ tidal current, mean wind stress and Scotian Shelf inflow, we examine the distribution of cod and haddock larvae spawned on the Northeast Peak of the Bank. The sensitivity to a March-April baroclinic field is also explored. Results indicate that larvae remaining in the surface Ekman layer are generally advected off-bank. However, downwelling associated with Ekman layer convergence near the shelf break provides a mechanism for larvae to exit from the off-bank surface drift. Larvae below the surface layer are transported south-westward along the southern flank of Georges Bank and are retained on the Bank if their position immediately upstream of the Great South Channel is shoalward of (roughly) the 70 m isobath. Within the Great South Channel region and between the 50 and 70 m isobaths, retention can depend on the phase of the tide. Spawning shoalward of the 50 m isobath on the Northeast Peak greatly increases the chances of retention. These results apply to passive larvae and to those with specified vertical distributions and migration based on observations. Directional on-bank swimming at rates of 0.5 to 1 body length per second would substantially enhance shoalward displacement, resulting in larval distributions during the first 2 months that are consistent with field observations.  相似文献   

Eulerian views of layered water currents, vertical distribution of some larval fishes, and inferred advective transport over the continental shelf off North Carolina, USA, in winter   总被引：1，自引：0，他引：1  

JOHN J. GOVONI  LEONARD J. PIETRAFESA 《Fisheries Oceanography》1994,3(2):120-132

Currents that effect the shoreward transport of the larvae of estuarine-dependent fishes spawned in winter in Onslow Bay, North Carolina, USA, were driven by winds and pressure gradients, and influenced by the Gulf Stream. Aside from storms, winds over the continental shelf in Onslow Bay blew predominantly alongshore with velocities approaching 14 m s^-1 during February and March 1986, and January and February 1989. Water masses and currents observed at two current-meter moorings, one at mid-shelf and the other on the outer shelf, reflected the onshore (or offshore) advection of interior water in compensation for the offshore (or onshore) advection of wind-driven surface water. Winds and currents reversed direction approximately every 4 to 6 days. The larvae of Atlantic menhaden, Brevoortia tyrannus , spot, Leiostomus xan- thurus, and Atlantic croaker, Micropogonias undulatus , were most abundant in 17–19^oC and 20–21^oC water of the outer shelf and Gulf Stream fronts. There was little indication of diel vertical migration; larval Atlantic menhaden were most abundant in mid- and surface water, while spot and Atlantic croaker were most abundant in mid- and deep water. Given this distribution, the inferred advective transport of larvae was at times onshore, but at other times it was offshore. Within a spawning season, the prevalence of either reciprocation could determine the number of larvae that reach coastal inlets.  相似文献   

Sampling error resulting from depth-dependent plankton distributions and current differentials in a two-layered system     

JOHN T. ANDERSON†  IAN T. WEBSTER‡ 《Fisheries Oceanography》1992,1(3):208-215

We evaluate a source of error observed in standard ichthyoplankton bongo tows in which volumes of water filtered did not result in increased catches of red-fish. Our analyses demonstrate that, under conditions where redfish larvae are distributed in surface waters in a two-layered system, current differentials between surface and subsurface layers resulted in biased, standardized estimates of larval abundances as a result of filtering varying amounts of subsurface waters. Analysis of standard survey results on Flemish Cap demonstrated that this source of bias was limited to the May-June period, after waters became stratified and before redfish passed from the larvae to pelagic juvenile stage. Correcting for this source of sampling bias wIII result in more accurate absolute estimates of ichthyoplankton abundance, and we estimate that variation (CV) for replicate samples may be reduced by 10%.  相似文献   

Femoral Capital Physeal Fractures in 25 Foals     

DAVID A. HUNT DVM    JACK R. SNYDER DVM  PhD  DiplomateACVs    JOE P. MORGAN DVM  Vet Med Dr  DiplomateACVR  JOHN R. PASCOE BVSC  PhD 《Veterinary surgery : VS》1990,19(1):41-49

The medical records of 25 horses 1 year of age or younger affected with femoral head and neck fractures during an 18 year period were reviewed. Each fracture involved the capital physis. The foals were 11 days to 12 months of age (mean, 5 months). No femoral capital physeal fractures occurred in horses older than 1 year of age during the same period. The history in each case included acute onset of severe unilateral hindlimb lameness, 3 hours to 2 months (mean, 12 days) before presentation. Injuries observed were violent falls, struggles, and kicks. Crepitation, swelling, pain with manipulation or palpation or both, and apparent fracture fragment displacement were inconsistently noted. Tentative clinical diagnoses were confirmed by radiography in 24 foals and by necropsy alone in one foal. Twenty-one foals were euthanatized due to poor prognosis. One foal sent home for stall rest was lost to follow-up. Surgical repair was attempted in three foals. Two fractures were repaired with multiple intramedullary pins and the foals were euthanatized within 2 weeks due to surgical failure and, in one case, contralateral limb breakdown. The third fracture was repaired with a compressing screw and plate device; the animal was pasture sound at month 20.  相似文献   

Dealing with exotic pets     

JOHN E. COOPER 《The Journal of small animal practice》1991,32(11):541-541

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Evaluation of Percutaneous Gastrostomy as a Technique for Permanent Gastropexy   总被引：1，自引：0，他引：1  

MICHELLE J. WASCHAK DVM    JOHN T. PAYNE DVM  MS  Dipiomate ACVS    ERIC R. POPE DVM  MS  Dipiomate ACVS    BRENT D. JONES DVM  COLETTE C. WAGNER-MANN MA  DVM  PhD 《Veterinary surgery : VS》1997,26(3):235-241

Objective- This study was designed to evaluate right-sided percutaneous endoscopic gastrostomy (PEG) as a method for creation of a permanent gastropexy.
Study Design- Percutaneous endoscopic gastrostomy adhesions were evaluated by gross examination and by mechanical testing and the results were compared with those obtained by conventional incisional gastropexy.
Animals or Sample Population- Fourteen mixed-breed dogs.
Methods- Incisional gastropexies were performed on the dogs of group one (N = 7) and PEG tubes were placed in the dogs of group 2 (N = 7). All skin sutures (group 1) and PEG tubes (group 2) were removed on day 14. The animals were maintained for an additional 44 days before euthanasia and immediate necropsy. Gastropexy adhesions were evaluated and collected for biomechanical evaluation using a materials testing machine.
Results- The duration of the procedure for group 2 was less (32.86 min ±7.65) than for group 1 (56.29 min ±8.28). The number of complications was not significantly different between group 1 and group 2 ( P =.103). Gastroperitoneal adhesions were present in 7 of 7 dogs in group 1 and 4 of 7 dogs in group 2. The adhesion lengths and widths were significantly larger in dogs in group 1 compared with those in group 2. The adhesions present in group 1 dogs sustained significantly greater tensile loads to failure (61.98 ±14.65 N), compared with the adhesions present in group 2 dogs (22.31 ±26.87 N).
Conclusions- Right-sided PEG inconsistently formed a weak gastropexy and the procedure was associated with a trend toward greater morbidity than incisional gastropexy.
Clinical Relevance- Right-sided PEG is not recommended as a means of prophylactic gastropexy.  相似文献   

Evaluating Alternative Regional Planning Models     

JOHN B. CRIHFIELD  HARRISON S. CAMPBELL 《Growth and change》1991,22(2):1-16

The REMI and IMPLAN models are widely used approaches to estimating economic impacts for small regions. However, few benchmarks exist for assessing these estimates. This paper evaluates the relative performance of these models in terms of a given impact: the opening of an automobile assembly plant in central Illinois. Although our results are not conclusive and are limited by our application, we find that in terms of several indirect performance criteria, IMPLAN's outcomes, on balance, are somewhat more plausible than those for REMI.  相似文献   

Housing Demand,Coping Strategy,and Selection Bias     

JOHN R. MIRON 《Growth and change》2004,35(2):220-261

ABSTRACT In conventional modeling of housing demand, consumers choose living arrangement, tenure, and housing on the basis of price, income, wealth, and tastes. However, it is both costly and onerous to alter one's housing conditions. It is argued therefore that consumers employ housing strategies to cope with labor market risks and expectations about their future: strategies that may differ from one demographic group to the next. In conventional modeling of housing demand, it is also well‐known that selection bias can arise: that is, omitted variables that help account for one aspect of housing (say, tenure choice) also subsequently affect the nature of the demand function for other aspects of housing demand (say, the amount spent on housing by a renter household). One such variable is the consumer's wealth, a variable that is typically not available in household survey data. This paper argues that the most important variables that may give rise to selection bias are variables that also reflect the coping strategies employed by consumers. The paper estimates a model of housing choice using Canada‐wide pooled samples from the 1980s and 1990s. In this paper, the prices of housing services and income prospects vary region by region. The paper shows how individuals and families in different housing markets across Canada respond, and how this evidences the use of coping strategies (from doubling up to substandard housing). The paper presents evidence to support the argument that selection bias is important in understanding how consumers cope.  相似文献