bluuebunny/crossref_metadata_2025 huggingface dataset:
Isentropic zonal average formalism and the near‐surface circulation
Authors: Koh T.‐Y. , Plumb R. A.
Published: July 2004

The isentropic zonal average formalism is extended to include a rigorous treatment of the bottom boundary of the atmosphere. We define a ‘surface zone’, where isentropes in the latitudinal plane are interrupted by the earth's surface. The zonal average equations of motion and their time average in isentropic coordinates are rederived in the presence of the surface zone. Applying the extended formalism to a baroclinic wave model, we show that near‐surface equatorward mean flow is driven by eastward surface form drag in isentropic coordinates, which in turn is related to poleward geostrophic potential temperature flux at the surface. A potential vorticity–potential temperature picture of extratropical general circulation dynamics above and within the surface zone is presented. We highlight the importance of poleward mean flow in the upper region of the surface zone and investigate the antisymmetric distribution of mean meridional mass flow about the median potential temperature of surface air. Copyright © 2004 Royal Meteorological Society.
A numerical study of moist stratified flow regimes over isolated topography
Authors: Miglietta M. M. , Buzzi A.
Published: July 2004

Numerical simulations of moist flows over simply shaped, three‐dimensional mountains were undertaken using a mesoscale meteorological model, with the purpose of examining the existence of different flow regimes near obstacles and the transitions among them. Moving the system in parameter space resulted in different solutions for a particular set of parameters. This method was adopted to explore numerically ‘multiple regimes’, stable for at least meteorologically interesting time periods. The evolution of the flow was studied in two different experimental set‐ups. In the first case, the height of the obstacle was progressively changed over time. In the second case, the effect of an advective change of the humidity content inside the channel was analysed. In both experiments, a dependence on the history of the flow became apparent.

A comparison among cases of obstacles with the same aspect ratio and non‐dimensional height, but with different horizontal cross‐sections, highlighted the importance of the obstacle geometry in perturbing the upstream flow, favouring the persistence of upstream blocked regions in the case of an arc‐shaped mountain.

The sensitivity of the reversal flow volume to several control parameters was analysed with additional experiments. In particular, the importance of the cooling associated with the evaporation of precipitation was emphasized. Copyright © 2004 Royal Meteorological Society.
Simultaneous radar and aircraft observations of mixed‐phase cloud at the 100 m scale
Authors: Field P. R. , Hogan R. J. , Brown P. R. A. , Illingworth A. J. , Choularton T. W. , Kaye P. H. , Hirst E. , Greenaway R.
Published: July 2004

Three UK C‐130 aircraft flights performed in conjunction with the Chilbolton Advanced Meteorological Radar were carried out in mixed‐phase clouds. The aircraft instrumentation included the Small Ice Detector (SID) and Nevzorov probe that are both capable of discriminating between liquid and ice phase. It was found that particle sphericity measured by the SID could be successfully used as a proxy for particle phase. Using a combination of the SID and other probes it is possible to determine whether a 100 m cloud segment is ice, liquid or mixed‐phase. Regions as short as 100 m exhibited mixed‐phase characteristics. There was generally good agreement between water phase indicated by the SID and Nevzorov probes, with any differences arising from the fact that the SID provides a number‐weighted estimate of dominant phase, while the Nevzorov probe provides a mass‐weighted estimate. The radar and aircraft observations show that when high values of differential reflectivity are observed the nearby presence of liquid water is indicated. When large ice crystals are present in deeper cloud they can suppress the differential reflectivity signal. Therefore the absence of a high differential reflectivity signal does not necessarily mean that liquid water is absent. © Royal Meteorological Society, 2004. P. R. Field's and P. R. A. Brown's contributions are Crown copyright.
Impact of ERS scatterometer winds in ECMWF's assimilation system
Authors: Isaksen Lars , Janssen Peter A. E. M.
Published: July 2004

The impact of ERS scatterometer winds on the European Centre for Medium‐Range Weather Forecasts (ECMWF) three‐dimensional variational (3D‐Var) and four‐dimensional variational (4D‐Var) assimilation systems is investigated. ERS scatterometer winds are found to be of consistent high quality in comparison to other surface wind observations. Both 3D‐Var and 4D‐Var systems assimilate the data well and a small, but significant, positive impact is found on medium‐range weather and wave forecasts. ERS scatterometer winds are not affected by rain or clouds, so they give valuable wind information near intense cyclones, tropical cyclones and in baro‐clinic regions. It is shown how the 4D‐Var method allows for dynamically consistent propagation of the surface wind information in the vertical. Four case studies that highlight important aspects of ERS scatterometer wind assimilation are presented. The main drawback for the ERS scatterometer instrument is the rather narrow swath compared with most other satellite instruments. Copyright © 2004 Royal Meteorological Society.
Neglect by GCMs of subgrid‐scale horizontal variations in cloud‐droplet effective radius: A diagnostic radiative analysis
Authors: Barker H. W. , Räisänen P.
Published: July 2004

Output from a global climate model (GCM) that employed a low‐resolution two‐dimensional cloud‐system‐resolving model (CSRM) in each column is used to assess the radiative impact of neglecting subgrid‐scale horizontal variations in cloud‐droplet effective radius re. For this diagnostic study, only liquid‐phase variations in re are addressed; the ice‐cloud particle distributions are assumed to be constant. For reference calculations, values of re in the CSRM cells are computed assuming that the droplet‐number concentration Ncld and the effective variance of droplet‐size distribution are constant in a GCM cell. The independent‐column approximation is used to produce flux profiles for each GCM column. Three alternative methods of setting horizontally‐invariant re are examined, each of which resemble how re is set in one‐dimensional radiative‐transfer models. Relative to the reference calculations, the other methods lead to positive spurious radiative forcings at the surface and at the top of the atmosphere. These stem from overestimation of optical‐depth variability and, thus, reduced short‐wave albedo of clouds. Globally averaged, these forcings range from 1 W m−2 to 3 W m−2, with zonal‐mean biases reaching almost 15 W m−2. The most severe biases arise from use of constant values of re over the land and the ocean.

In addition, radiative effects due to unacknowledged uncertainty in Ncld (or re) are assessed. It is shown that ad hoc, but not outlandish, estimates of unbiased uncertainty in Ncld impart biases on estimates of the earth's solar‐radiation budget (tantamount to a spurious radiative forcing). These arise through the chain of nonlinear relations that link Ncld to solar radiative transfer. Copyright © 2004 Royal Meteorological Society.
The sensitivity of simulated orographic precipitation to model components other than cloud microphysics
Authors: Zängl G.
Published: July 2004

Numerical simulations of an orographic precipitation event observed during the MAP field phase are presented in order to investigate side effects on the simulated precipitation. The simulations are conducted with the Penn State University—National Center for Atmospheric Research mesoscale model MM5 in a configuration with four interactively nested domains and a finest grid spacing of 1.4 km. The sensitivity tests examine the impact of the boundary‐layer parametrization, the set‐up of the convection parametrizations in the outer model domains, the implementation of the horizontal diffusion and the specification of the vertical coordinate. For reference, five different cloud microphysical parametrizations are compared against each other.

The results show that each of the side effects arising from the model numerics and from the physics parametrizations not related to cloud microphysics can be as large as, or even larger than, the impact of the microphysical parametrization itself. A particularly large sensitivity is found for the horizontal diffusion of temperature and moisture. Computing this diffusion along the terrain‐following coordinate surfaces rather than truly horizontally increases the average precipitation in the 1.4 km domain by about 35%, and a comparison with surface observations indicates a pronounced deterioration of the model results. The other sensitivities are found to range between 10% and 15% on a domain average. An important conclusion emanating from these results is that future model development should pay much more attention to the cross‐sensitivities between the model numerics, the convection and boundary‐layer parametrizations and the cloud microphysical parametrization. Copyright © 2004 Royal Meteorological Society.
Oxidized nitrogen and ozone interaction with forests. I: Experimental observations and analysis of exchange with Douglas fir
Authors: Dorsey J. R. , Duyzer J. H. , Gallagher M. W. , Coe H. , Pilegaard K. , Weststrate J. H. , Jensen N. O. , Walton S.
Published: July 2004

Measurements of NOx and O3 exchange to and from a forest canopy are described with reference to canopy and ecosystem processes leading to emission of NO2. The soil below the forested measurement location is shown to be a net source of reactive oxidized nitrogen (as NO). It is shown that a large fraction (around 58% on average) of the emitted NO escapes out of the trunk space to react within and above the canopy.

Fluxes of NO2 above the canopy are bi‐directional, with large fluxes and most emission events taking place during the day. Deposition is shown to take place without significant changes in the vertical flux; however there appears to be rapid chemical reaction leading to significant flux divergence taking place during emission events. Above the top of the canopy (22 m), changes of 200% in the NO2 flux between 25 and 35 m are not uncommon.

Ozone deposition to the forest system has been investigated. The flux is often related to stomatal deposition, but there are periods when large non‐stomatal fluxes are observed. At night there is a large vertical divergence in the ozone flux above the canopy, probably related to reaction with NO from the forest soil. The reaction of O3 with volatile organic compounds is found, in general, to be negligible with respect to ozone concentrations and fluxes.

Ozone is found to deposit mainly to leaf stomata during the day, with a small but not insignificant contribution from NO reaction. However, the nocturnal ozone budget for the forest changes significantly, with most of the measured deposition accounted for by soil uptake and reaction with NO. The resultant problems related to inadequate treatment of air chemistry when interpreting O3 fluxes in high NO emission environments are identified. Copyright © 2004 Royal Meteorological Society.
Oxidized nitrogen and ozone interaction with forests. II: Multi‐layer process‐oriented modelling results and a sensitivity study for Douglas fir
Authors: Duyzer J. H. , Dorsey J. R. , Gallagher M. W. , Pilegaard K. , Walton S.
Published: July 2004

An existing process‐oriented multi‐layer canopy model is applied to data from an intensive NOx and O3 surface exchange experiment, and a sensitivity study is conducted. The canopy was a mature 22.5 m Douglas fir stand.

Comparison of measured data and model results shows that the model represents the concentration and fluxes of ozone well above the canopy, with adequate accuracy for concentration and fluxes below the canopy. A similar pattern is demonstrated for NO2 concentration above and below a forest canopy, with the fluxes being calculated correctly to within at least an order of magnitude below the canopy, and more accurately above. The model can reproduce the processes leading to the observed NO2 emission from forest stands.

The sensitivity study demonstrates the complex interdependence of oxidized nitrogen flux controlling variables within the canopy, with NO2 emission favoured by high NO soil emission and canopy resistance and by low global radiation, leaf area index and ambient NO2 concentrations. Realistic alterations of these variables can cause reversal of the NO2 flux, leading to an ‘ecosystem compensation point’ between 17 and 35 ppbv at night, and 5 to 10 ppbv during the day for the forest canopy investigated. This highlights our improved understanding of the controls on NO2 flux, explaining and quantifying some previously reported reversals in NO2 flux above forest canopies.

The effect of soil NO emission on ozone flux is investigated. During the day, reaction with NO may account for only 10% of observed ozone deposition, however, at night, this figure can rise to around 50%. The effect of volatile organic compounds on forest ozone deposition was found not to be large. Copyright © 2004 Royal Meteorological Society.
Numerical simulations of the 12–13 August 2002 flooding event in eastern Germany
Authors: Zängl G.
Published: July 2004

In this paper, high‐resolution numerical simulations of the 12–13 August 2002 flooding event in eastern Germany are presented. The simulations are performed with the Penn State/National Center for Atmospheric Research mesoscale model MM5 in a four‐domain configuration with a finest horizontal resolution of 1 km. Sensitivity experiments are performed with coarser resolutions (3 and 9 km), with different cloud microphysical parametrizations and with a different date of initialization. Moreover, tests with 1 km resolution but the smoothed topography of the 9 km runs are conducted in order to isolate the contribution of the model topography to the differences between the 1 km runs and the 9 km runs.

The results show that the high‐resolution runs reproduce the observed structure of the precipitation field very well. In particular, the location of the rainfall maximum is correct to within 15 km. The quantitative agreement between model results and observations is fairly good in regions with light to moderate rain, but large amounts of precipitation tend to be underpredicted. For observed 36‐hour rainfall accumulations exceeding 200 mm, the negative bias typically ranges between 15 and 30 Copyright © 2004 Royal Meteorological Society.
Cloud characteristics and channel selection for IASI radiances in meteorologically sensitive areas
Authors: Fourri'e Nadia , Rabier Florence
Published: July 2004

The cloudiness in simulated Infrared Atmospheric Sounding Interferometer (IASI) pixels deduced from the Advanced Very‐High‐Resolution Radiometer (AVHRR) satellite imager is studied specifically in meteorologically sensitive areas during the Fronts and Atlantic Storm‐Track Experiment. It is found that few clear AVHRR observations are located in the IASI pixels in these regions, which are covered by high‐level and low‐level clouds. The IASI channel selection is then studied in the context of the sensitive areas for the pixels with low‐level clouds. The Entropy Reduction (ER) method, which was previously studied in a general context, is compared with two other channel selection methods using selection criteria based on adjoint sensitivity: the sensitivity to observations and the so‐called Kalman‐filter sensitivity. It is found that, even though the ‘sensitive’ methods give slightly better results than the ER one, the latter performs quite robustly and at a lower computational cost. The robustness to the specification of the background‐error covariance matrix is then studied. It is shown that channel selection based on the ER method is particularly robust to the specification of the background‐error covariance matrix, but the analysis step itself requires an accurate determination of the background‐error covariance matrix. In addition it is shown that an independently computed constant channel set gives comparable results to the optimal channel set. Copyright © 2004 Royal Meteorological Society.
1/f noise and pulse‐like events in the tropical atmospheric surface variabilities
Authors: Yano Jun‐ichi , Blender Richard , Zhang Chidong , Fraedrich Klaus
Published: July 2004

This study discusses the 1/f ‐noise behaviour and its connection with pulse‐like events in tropical surface meteorological data. The 1/f noise, withf being frequency, refers to the unique spectrum shape of signals that represents the same degree of variability for a whole spectrum range with very long lag‐correlations. The pulse‐like events are characterized by their high localizations in time and a lack of a distinct spectrum peak.

Approximate 1/f ‐noise behaviour is found in tropical surface temperature, moisture, and wind speed for periods of 1 hour to beyond 10 days and in oceanic wind stress up to 2‐year periods. The origin of the 1/f noise can be closely tied to pulse‐like events with a highly intermittent nature in the time series. Examples for such pulse‐like events include the cumulus convection events leading to convective downdraughts and intraseasonal westerly wind events associated with the Madden–Julian oscillations (MJO). A method based on the wavelet is introduced to extract individual pulse‐like events. These events are characterized by a 1/f spectrum extending up to 1–2 decades of frequency centred around their characteristic durations. Their successive occurrences are mutually uncorrelated and the individual pulse‐like events themselves constitute a 1/f spectrum for a frequency range around their durations. The superposition of these events of various durations yields the 1/f ‐noise spectrum for much wider ranges. Physical implications of these findings to convective quasi‐equilibrium and MJO‐El Niño Southern Oscillation relationship are discussed. Copyright © 2004 Royal Meteorological Society.
Benjamin–Feir instability of Rossby waves on a jet
Authors: Esler J. G.
Published: July 2004

Large‐scale waves on the extratropical tropopause have been widely observed to spontaneously organize into groups or wave packets. Here, a simple paradigm for this wave packet formation is presented. Firstly, a weakly nonlinear theory of Rossby wave propagation on a potential‐vorticity front, based on small non‐dimensional wave amplitude ε, is developed. As is typical for systems allowing conservative one‐dimensional wave propagation, the evolution of the wave envelope is governed by the nonlinear Schrödinger equation. The sense of the nonlinearity is consistent with Benjamin–Feir instability, where uniform wave trains are unstable to sideband modulations, leading to the formation of wave packets. Next, numerical results from contour dynamics integrations show that the weakly nonlinear predictions for sideband growth rates are quantitatively accurate up to ε∼0.5, and that unstable sideband growth is qualitatively similar, but slower than predicted, at higher values of ε. For ε≥0.6 the formation of wave packets leads to wave‐breaking, this occuring at much lower initial wave amplitudes than for unmodulated uniform wave trains previously studied. The numerical results reveal that the length and time‐scales of the Benjamin–Feir instability are broadly consistent with observed wave packet formation in the extratropics. Copyright © 2004 Royal Meteorological Society.
The Implicit Religion of Love
Authors: Lamb Christopher
Published: July 2004

Love is not merely the highest goal of the world religions but also is an implicit religion in its own right. This is demonstrated through an examination of the theme of love in a range of secular literature, poetry, prose and commentary from ancient and modern sources. Often at odds with overt religious mores, love seems an ameliorating and transforming human experience.
Infinite Justice
Authors: Allcock John B.
Published: July 2004

The article sets out from the idea that it might be interesting and helpful to look at emerging international judicial institutions in terms of implicit religion, which exemplify the human search for transcendent justice. This possibility is explored in relation to the International Criminal Tribunal for the former Yugoslavia. The problems attending such institutions are reviewed, suggesting that they must inevitably fail to meet our expectations for ‘infinite justice’. Addressing aspects of justice such as restitution, reconciliation and forgiveness, other mechanisms are being developed which have a more explicitly religious character. The article concludes with a critical examination of general approaches to implicit religion in terms of its functional equivalence to conventionally defined religion.
Ability of Electric Field Strength, Frequency, and Current Duration to Stun Farmed Atlantic Salmon and Pollock and Relations to Observed Injuries Using Sinusoidal and Square Wave Alternating Current
Authors: Roth Bjorn , Moeller Dag , Slinde Erik
Published: July 2004

The effects of electricity as a stunning method in the slaughtering process of Atlantic salmon Salmo salar and pollock Pollachius virens were studied. About 330 slaughter-sized Atlantic salmon were exposed to sinusoidal alternating current (AC) in seawater. Electrical field strength ranged from 25 to 100 V/m and current duration from 1 to 10 s at frequencies between 30 and 2,000 Hz. In addition, 122 pollock and 25 salmon were stunned by applying square wave AC in the range of 50–1,000 Hz. After stunning, subsequent unconsciousness was evaluated by means of behavioral responses, and injuries were observed by examining fillets. For sinusoidal AC, the proportion of Atlantic salmon sufficiently stunned and the occurrences of obviously broken spinal columns and hemorrhages were dependent on the electrical frequency used. The AC frequency was the most predominant factor in both stunning and inflicted injuries. The proportion of injured salmon exhibited a unimodal response to sinusoidal AC frequency, increasing from 30 Hz to 50– 80 Hz and declining with higher frequencies. There was not a consistent injury-versus-frequency pattern for pollock exposed to square wave AC. For Atlantic salmon, use of square wave AC did inflict a higher rate of injuries than that of sinusoidal AC. For minimizing the occurrence of injuries while sustaining sufficient stunning before slaughter, sinusoidal AC frequencies between 500 and 1,000 Hz are recommended at field strengths exceeding 50 V/m and current durations of 10 s.
Effects of Clove Oil, Tricaine, and CO2 on Gamete Quality in Steelhead and White Sturgeon
Authors: Holcomb M , Woolsey J , Cloud J G , Ingermann R L
Published: July 2004

This study examined the direct impact of three commonly used anesthetics—clove oil (86% eugenol), tricaine (tricaine methanesulfonate [MS-222]), and CO2—on egg quality for steelhead Oncorhynchus mykiss and that of clove oil and tricaine on the motility of sperm from both steelhead and white sturgeon Acipenser transmontanus. Exposure of unfertilized eggs for 6 or 24 h to 150 mg clove oil/L, 225 mg tricaine/L, or less than 100 mm Hg CO2 resulted in no reduction in egg fertility or embryo survival to hatch. However, higher doses (1,500 mg clove oil/L; 2,250 and 22,500 mg tricaine/L; or more than 125 mm Hg CO2) negatively impacted egg quality. Similarly, a 3-h exposure to clove oil (150 mg/L) or tricaine (225 mg/L) produced no significant effect on sperm motility in steelhead. White sturgeon sperm showed a modest decline in motility after incubation in clove oil. Thus, the data suggest that clove oil and tricaine can be used on fish prior to gamete harvesting without significant adverse impacts on gametes. Although CO2 is unlikely to have deleterious effects on eggs, CO2-associated declines in ovarian fluid pH may be of concern when ovarian fluid pH is used as an indicator of egg quality.
Comparison of Production, Meat Yield, and Meat Quality Traits of NWAC103 Line Channel Catfish, Norris Line Channel Catfish, and Female Channel Catfish × Male Blue Catfish F1 Hybrids
Authors: Bosworth Brian G , Wolters William R , Silva Juan L , Chamul Roberto S , Park Sinyoung
Published: July 2004

NWAC103 line channel catfish Ictalurus punctatus, Norris line channel catfish, and Norris line female channel catfish × Dycus Farm line male blue catfish I. furcatus F1 hybrids were compared for production, meat yield, and meat quality traits. Juvenile fish from each genetic group were stocked at 12,000 fish/ha into three, 0.04-ha ponds per genetic group. Fish were fed once daily to satiation from June through October, and fed on days when afternoon water temperatures were above 17°C from November through December. Fish were harvested, weighed, and counted in January, and 150 fish per genetic group (50 fish per pond) were processed and measured for meat and body component yield. Instrumental and sensory panel evaluations of quality were measured on fresh, frozen-thawed, and baked fillets. Stocking weight, harvest weight, and net production (kg/ha) were highest for the NWAC103 line channel catfish, intermediate for the hybrid, and lowest for the Norris line channel catfish. Growth at unit size (a), percent weight gain, survival, and feed conversion were not significantly different among genetic groups. Carcass yield (relative to whole weight) and fillet yield were higher for the hybrid than for the two channel catfish lines, and higher for females than for males in all genetic groups. Head yield and total viscera yield were higher for the channel catfish lines than the hybrid. Head yield was higher for males than for females, and total viscera yield was higher for females than for males. Visceral fat yield was higher for the hybrid than for the two channel catfish lines. Instrumental and sensory panel analysis indicated only minor differences among genetic groups for fillet quality. Thus, catfish producers and processors can improve important traits and increase profits by utilizing catfish lines with superior performance.
Application of Chemical Coagulation Aids for the Removal of Suspended Solids (TSS) and Phosphorus from the Microscreen Effluent Discharge of an Intensive Recirculating Aquaculture System
Authors: Ebeling James M , Ogden Sarah R , Sibrell Philip L , Rishel Kata L
Published: July 2004

An evaluation of two commonly used coagulation–flocculation aids (alum and ferric chloride) was conducted to determine optimum conditions for treating the backwash effluent from microscreen filters in an intensive recirculating aquaculture system. Tests were carried out to evaluate the dosages and conditions (mixing and flocculation stirring speeds, durations, and settling times) required to achieve optimum waste capture. The orthophosphate removal efficiency for alum and ferric chloride were greater than 90% at a dosage of 60 mg/L. Optimum turbidity removal was achieved with a 60-mg/L dosage for both alum and ferric chloride. Both alum and ferric chloride demonstrated excellent removal of suspended solids from initial total suspended solid values of approximately 320 mg/L to approximately 10 mg/L at a dosage of 60 mg/L. Flocculation and mixing speed and duration played only a minor role in the removal efficiencies for both orthophosphates and suspended solids. Both coagulation–flocculation aids also exhibited excellent settling characteristics, with the majority of the floc quickly settling out in the first 5 min.
Changes in Water Hardness Influence Colonization of Saprolegnia diclina
Authors: Barnes Michael E , Gabel Audrey C , Durben Dan J , Hightower Timothy R , Berger Tate J
Published: July 2004

Experiments were conducted to determine the effects of different water hardness concentrations on colonization of Saprolegnia diclina in an attempt to explain some of the differences in fungal growth and antifungal chemical effectiveness observed at various fish hatcheries. Fungal growth on nonviable seeds of hemp Cannabis sativa was observed significantly sooner in water where hardness was elevated due to the addition of calcium sulfate dihydrate in each of the experiments. Seeds in test tubes containing water with a hardness of 300 mg/L exhibited fungal colonization in approximately one-half the amount of time observed with seeds in water with hardness less than 150 mg/L. In petri dishes containing inoculated corn meal plugs, the growth of S. diclina was observed at only 24 h on seeds in water with a hardness of 450 mg/L, which was significantly quicker than the 31 h from seeds in water hardness of 150 and 300 mg/L. This, in turn, was significantly quicker than the 35 h required for growth in the 0 mg/L hardness control water. Results were similar in a subsequent experiment where the inoculated plugs were removed from the petri dishes prior to seed placement. The relatively minor changes in pH following the addition of water hardness-altering chemicals did not affect the timing of fungal colonization, as a separate experiment indicated no differences in fungal growth in pH ranging from 3 to 10.
Demonstrating Data and Test Result Validity for Diagnostic Aquatic Animal Health Laboratories
Authors: Wiegers Ann L. , Heidel Jerry R. , Scarfe A. David
Published: July 2004

The information in this article is aimed towards the managers in laboratories that conduct testing in support of aquatic animal disease diagnosis or the determination of health status. This includes laboratories that do regulatory work—directly or indirectly—those who do testing for trade, and those who will be required to respond swiftly and effectively in the case of a national animal health emergency. The ability to demonstrate validity is essential for national security, protection of public and animal health, minimization of liability, and support of business and trade. Veterinarians, wildlife specialists, and aquatic animal health specialists may also find it valuable, as many points are directly pertinent to the establishment of a quality program in a clinical or individual practice laboratory. Data and test result validity are critical to timely and accurate diagnosis and treatment, effective disease and health management, reliable surveillance, and quick, appropriate responses in the event of an animal health emergency. There are currently four general areas of importance regarding the demonstration of data and test result validity: The conduct of testing; the use of valid, approved test methods; proficiency testing; and the use of reference materials. Demonstration of validity is achieved via the implementation and use of appropriate and documented technical, operational, and managerial policies, systems, procedures, and specifications that are scientifically sound, that meet the requirements of relevant third-party consensus standards, and that can be verified by recognized, third-party accreditation. The basis for the requirements of laboratory accreditation and accreditation body recognition programs in the United States and internationally that address these areas of analytical endeavor is discussed. Recent legislation and activities in establishing a unified national system of accreditation that meets applicable international standards may assist in creating national laboratory systems capable of effectively addressing data and test result validity and credibility in critical diagnostic areas.
Invasion Route and Pathogenic Mechanisms of Vibrio alginolyticus to Silver Sea Bream Sparus sarba
Authors: Li Jun , Zhou Liran , Woo Norman Y. S.
Published: July 2004

Potential routes of invasion and associated pathogenic mechanisms of a pathogenic strain of Vibrio alginolyticus (Vib-01) to silver sea bream Sparus sarba were evaluated. Inoculation of V. alginolyticus into juvenile silver sea bream via the intramuscular, intraperitoneal, injury–immersion, and simple immersion routes resulted in 14-d LD50 values (concentrations lethal to half the group studied) of 4.85 × 104 colony-forming units [cfu]/fish, 5.01 × 105 cfu/fish, 3.16 × 106 cfu/mL and more than 2.5 × 108 cfu/mL, respectively. These findings suggest that the integrity of the fish integument is important for protecting fish against vibriosis, such that invasion through integumental breaches would be the main invasive mode of this bacterium to silver sea bream. Phagocytic activities of splenic and pronephric macrophages were significantly increased at the early stages of infection but declined significantly as infection progressed (after 24 or 36 h). The spleen and head kidney of fish inoculated with Vib-01 bacteria exhibited high bacterial counts accompanied by a decline in the phagocytic potential of the macrophages taken from both organs. Sea bream infected with V. alginolyticus exhibited significant decreases in red blood cell count, hematocrit, hemoglobin, serum glucose, and protein. Total leukocyte count increased at the early stages of infection but declined as infection became advanced. The destruction of critical components of both the circulatory and immune systems by V. alginolyticus could be the main cause of mortality in vibriosis. Extracellular products (ECPs) of the present V. alginolyticus isolate were toxic not only to silver sea bream but also to cultured fibroblast cells derived from sea bream fin tissue. The 14-day LD50 of ECPs to sea bream was 0.92 μg per gram of fish weight. Our data suggest an involvement of the ECPs, especially their hydrolytic and hemolytic components, in the invasive and proliferative processes of the bacteria in silver sea bream.
Safety of Oxytetracycline (Terramycin TM-100F) Administered in Feed to Hybrid Striped Bass, Walleyes, and Yellow Perch
Authors: Gaikowski Mark P. , Wolf Jeffrey C. , Schleis Susan M. , Gingerich William H.
Published: July 2004

Oxytetracycline (Terramycin TM-100F, a medicated premix containing oxytetracycline at 220 g/kg) is approved in the United States to control certain systemic bacterial diseases of salmon and catfish when fed at a rate of 55–82.5 mg per kilogram of bodyweight per day for 10 d. Although oxytetracycline may also control certain systemic bacterial infections in coolwater or scaled warmwater fish, no safety data for such species are available. Our objective was to determine the safety of oxytetracycline administered in feed at nominal doses of 0, 82.5, 248, or 413 mg · kg−1 · d−1 to yellow perch Perca flavescens and hybrid striped bass (striped bass Morone saxatilis × white bass M. chrysops) for 10 d and to walleye Sander vitreus (formerly Stizostedion vitreum) for 20 d. Yellow perch and hybrid striped bass consumed 50% to 100% of the diet, whereas walleye feed consumption was occasionally less than 50% of the diet. Feed or fecal material was present in the gastrointestinal tract of all necropsied walleyes except for one control fish. The single growth effect was that hybrid striped bass offered a nominal dose of 413 mg · kg−1 · d−1 were significantly smaller than untreated controls. Oxytetracycline-related histopathological findings were limited to walleyes and were of low severity. The histopathological findings included decreased hematopoietic–lymphopoietic (H&L) tissue in the anterior kidneys, diffuse hyperplasia of the gill filament epithelium, and a decreased prevalence of fish with eosinophilic droplets in their renal tubular epithelial cells. Although the incidence of decreased H&L tissue tended to increase in proportion to oxytetracycline dose, this finding was statistically significant only for fish that received a nominal dose of 413 mg · kg−1 · d−1. Given the pathogenicity of the types of bacteria that are controlled by oxytetracycline treatment and the long history of its use in major aquaculture species, the relative risk of the minor oxytetracycline-related changes observed in this study may be outweighed by disease control benefits.
Molecular, Physical, and Clinical Evidence that Golden Shiner Virus and Grass Carp Reovirus are Variants of the Same Virus
Authors: McEntire Mathew E. , Iwanowicz Luke R. , Goodwin Andrew E.
Published: July 2004

Moribund golden shiners Notemigonus crysoleucas sampled during winter and spring and moribund grass carp Ctenopharyngodon idella sampled during summer were necropsied and cultured on cyprinid cell lines. In all cases, a syncytial cytopathic effect occurred and viruses were successfully passaged. Characterization by electron microscopy, diethyl ether resistance, iododeoxyuridine resistance, and acid resistance confirmed that the isolates were aquareoviruses. We used polymerase chain reaction to test all isolates; primer sets were based on a published sequence for segments 1, 2, 3, and 10 of the grass carp reovirus (GCRV). Products of the expected sizes were amplified, then cloned and sequenced. The isolates were about 97–100% identical to each other and to a published sequence for golden shiner virus (GSV) and were 90–93% identical to GCRV. At the amino acid level, our isolates were 96–100% identical to each other and to GCRV. The similarity among our isolates and the published GCRV sequence was equivalent to the similarity among published GCRV sequences; we therefore conclude that GSV and GCRV are the same virus. This conclusion is confirmed by our isolation of this virus from both moribund golden shiners and moribund grass carp. Based on our work, we conclude that GSV is synonymous with GCRV, and that GSV was probably imported into the USA concurrently with the introduction of grass carp by federal agencies in 1963.
Comparison of Cellular and Extracellular Products Expressed by Virulent and Attenuated Strains of Edwardsiella ictaluri
Authors: Williams Michele L. , Azadi Parastoo , Lawrence Mark L.
Published: July 2004

Cellular and extracellular products of three virulent Edwardsiella ictaluri isolates were compared with corresponding attenuated strains to evaluate potential virulence factors. The characteristics compared included growth kinetics, hemolysin activity, surface structures, outer membrane protein profiles, and lipopolysaccharide profiles. To produce the attenuated strains, we passed three isolates through multiple subcultures in liquid media. Attenuated strains were found to have shorter generation times than virulent strains. They also apparently failed to express a 55-kdalton outer membrane protein that the virulent strains possessed. Scanning electron microscopy found no conclusive differences in surface structure expression. Hemolysin activity was significantly greater in virulent strain R4383 than in its corresponding attenuated strain. Lipopolysaccharide profiles showed no apparent differences in the O polysaccharide portion; however, the composition of core oligosaccharide sugars differed between the two.
Comparison of Cytochrome P450 2C9 Genotyping Methods and Implications for the Clinical Laboratory
Authors: Aquilante Christina L. , Lobmeyer Maximilian T. , Langaee Taimour Y. , Johnson Julie A.
Published: July 2004

Study Objective. To compare the accuracy, speed, and cost of two methodologies used for genotyping known variants in the cytochrome P450 (CYP) 2C9 metabolizing enzyme gene.

Design. Comparative study.

Setting. University research center.

Samples. Fifteen‐milliliter mouthwash samples collected from 253 subjects participating in a warfarin pharmacogenomic study.

Intervention. Genotyping for the isoleucine‐to‐leucine change at codon 359 (Ile359Leu [*3] polymorphism) was performed by using the Pyrosequencing and polymerase chain reaction (PCR)–restriction fragment length polymorphism (RFLP) methods in all 253 samples. Genotyping for the arginine‐to‐cysteine change at codon 144 (Arg144Cys [*2] polymorphism) was performed by using Pyrosequencing in all samples and by PCR‐RFLP in a random subset of 136 samples.

Measurements and Main Results. Comparisons of genotyping success rates, time efficiency, and cost analyses were conducted for Pyrosequencing and PCR‐RFLP at each variant site. Pyrosequencing and PCR‐RFLP produced similar success rates on the first genotyping attempt for the Arg144Cys variant (93.3% vs 90.4%, respectively) and the Ile359Leu variant (83.8% vs 79.1%, respectively). With Pyrosequencing, genotyping 96 samples for either polymorphism could be performed in 1 hour. In contrast, genotyping 96 samples by RFLP took 10 hours for the Arg144Cys variant and 20 hours for the Ile359Leu variant. Total cost/sample for Arg144Cys genotyping was $1.90 with PCR‐Pyrosequencing and $3.14 with PCR‐RFLP. Total cost/sample for Ile359Leu genotyping was $1.88 with PCR‐Pyrosequencing and $10.18 with PCR‐RFLP.

Conclusion. Compared with RFLP, genotype determination by Pyrosequencing is a more time‐efficient, cost‐effective, and robust method for CYP2C9 genotyping. Because of its wide applicability and ease of use, Pyrosequencing is a promising technology for future pharmacogenomic investigations.
Differences in Rates of Diarrhea in Patients with Human Immunodeficiency Virus Receiving Lopinavir‐Ritonavir or Nelfinavir
Authors: Guest Jodie L. , Ruffin Charnelda , Tschampa Jean M. , DeSilva Kathryn E. , Rimland David
Published: July 2004

Study Objective. To determine and compare rates of diarrhea in patients receiving an antiretroviral regimen containing lopinavir‐ritonavir versus nelfinavir and in patients who received these drugs sequentially.

Design. Retrospective cohort analysis.

Setting. Hospital‐based human immunodeficiency virus (HIV) clinic.

Patients. Four hundred one participants in the HIV Atlanta VA Cohort Study who were prescribed lopinavir‐ritonavir or nelfinavir from 1996–2002.

Measurements and Main Results. Chart review identified episodes of diarrhea that potentially were associated with an antiretroviral agent. Data collected included antidiarrheal agents dispensed, baseline viral load and CD4+ cell counts, demographic variables, and previous therapy. Diarrhea associated with an antiretroviral regimen occurred in 175 (49%) of 354 patients receiving nelfinavir and 17 (17%) of 99 patients receiving lopinavir‐ritonavir (p<0.001). Treatment for the diarrhea occurred in 118 (33%) of 354 patients receiving nelfinavir and 9 (9%) of 99 receiving lopinavir‐ritonavir (p<0.001). Patients in the lopinavir‐ritonavir group were more likely to have received highly active antiretroviral therapy and azithromycin than patients receiving nelfinavir, and they had lower baseline CD4+ cell counts (p≤0.01 for each comparison). The average number of months/person‐year of diarrhea treatment was 2.0 for the nelfinavir group and 0.13 for the lopinavir‐ritonavir group. Of the 10 antiretroviral‐naïve patients who received lopinavir‐ritonavir, none needed treatment for diarrhea, whereas 78 (36%) of 217 antiretroviral‐naïve patients who received nelfinavir required treatment for diarrhea. Of the 52 patients who had been taking nelfinavir and were switched to lopinavir‐ritonavir, they were more likely to start antidiarrheal treatment while taking nelfinavir (14 [27%]) than while receiving lopinavir‐ritonavir (3 [6%]) (p=0.004).

Conclusions. Patients receiving lopinavir‐ritonavir were significantly less likely to have diarrhea or to require treatment for diarrhea than patients receiving nelfinavir. The same results occurred when the drugs were given to the same patients sequentially (nelfinavir followed by lopinavir‐ritonavir). The diarrhea associated with lopinavir‐ritonavir was less frequent, less severe, and shorter in duration than diarrhea associated with nelfinavir.
Replication of the Weber Effect Using Postmarketing Adverse Event Reports Voluntarily Submitted to the United States Food and Drug Administration
Authors: Hartnell Nicole R. , Wilson James P.
Published: July 2004

Study Objective. To validate or refute a widely accepted epidemiologic phenomenon known as the Weber effect by replicating Weber's original observation by using drugs that were marketed in the United States and using reports from a U.S. database.

Design. Retrospective analysis of adverse event databases.

Setting. University research center.

Drugs. The original nonsteroidal antiinflammatory drugs studied by Weber that were approved by the U.S. Food and Drug Administration (FDA) and marketed in the United States: diclofenac sodium, diclofenac potassium, diflunisal, sulindac, flurbiprofen, and piroxicam.

Intervention. Reports of adverse events submitted to the FDA's Spontaneous Reporting System and the Adverse Event Reporting System from January 1969–December 2000 for these drugs were analyzed according to the number of adverse events reported for each drug per year from the time the drug was approved until December 2000.

Measurements and Main Results. Reporting patterns were considered to demonstrate the Weber effect if the highest peak in reports during the first 5 years after product approval occurred during year 2. All five drugs analyzed in this study demonstrated the Weber effect.

Conclusion. The Weber effect was replicable by using drugs marketed in the United States and using reports that were submitted to a U.S. database. Various other factors affected spontaneous reporting of adverse events, as peaks in the number of reports were seen numerous times for each drug after the initial 5‐year marketing period.
Anemia Management in Heart Failure: A Thick Review of Thin Data
Authors: McBride Brian F. , White C. Michael
Published: July 2004

Heart failure is defined as the inability of the heart to pump blood at an amount sufficient to meet the metabolic needs of the body. In heart failure, the inability to meet the body's metabolic needs is based on hemodynamic derangement and suboptimal oxygen‐carrying capacity of the blood itself. Current pharmacologic therapy attempts to improve survival and reduce symptomatology by optimizing hemodynamics to increase oxygen delivery, but does not address oxygen‐carrying capacity. Unfortunately, there is a high prevalence of anemia in patients with heart failure, which compromises oxygen‐carrying capacity, is an independent predictor of mortality, and may be caused in part by pharmacologic agents that confer morbidity and mortality benefits in this population. Recombinant human erythropoietin supplementation improves the functional capacity of the failing myocardium, reverses and antagonizes the detrimental remodeling induced by autoimmune activity, and may reduce mortality and morbidity among patients receiving maximal pharmacologic therapy for heart failure. However, limited clinical data prohibit widespread recommendations for its use in patients with heart failure.