Search Results - (Author, Cooperation:T. Meyers)

2011-11-19

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Air/analysis ; *Altitude ; Atmosphere/analysis ; Biophysical Processes ; Canada ; Climate ; Conservation of Natural Resources ; Forestry ; Seasons ; *Temperature ; Trees/*growth & development ; United States

1750-3841

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Process Engineering, Biotechnology, Nutrition Technology

Steaks from mechanically pressed tenderloins and steaks from paired, unpressed control tenderloins from Good and Choice grade steers were studied. Pressing did not adversely affect overall quality of the tenderloin steaks; however, fibers of the pressed steaks were kinked and compacted when compared to control steaks. No differences in fiber breakage or in sarcomere length were noted. Fat, moisture, lean color, marbling texture, marbling amount, lean texture, lean firmness and moisture on the steak surface were similar in pressed and unpressed steaks, Panel scores for tenderness, juiciness and flavor and Warner-Bratzler shear values were also similar for pressed and unpressed steaks. Pressed steaks had greater cooking loss, but they were more uniform in size and shape than control steaks.

Electronic Resource

1750-3841

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Process Engineering, Biotechnology, Nutrition Technology

The effects of steak location, storage time and precooking internal temperature upon steak quality were evaluated. Steaks from the anterior ends of the tenderloins were darker in color and displayed greater surface moisture than steaks from the posterior ends. Fresh-processed tenderloin steaks displayed more surface moisture than steaks from tenderloins stored 6 or 12 months. Warner-Bratzler shear values increased with storage. Steaks which were broiled starting at 1°C had less total thaw and cooking loss than steaks broiled frozen (-10°C) or thawed (24°C), but greater muscle separation occurred in thawed steaks. Palatability was not adversely affected by steak location, storage time or steak temperature prior to cooking.

Electronic Resource

1365-2761

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

Abstract. Viral erythrocytic necrosis (VEN) has been associated with large epizootics and high mortality in Pacific herring, Clupea harengus pallasi (Valenciennes), from two different locations in south-eastern Alaska, USA. Clinical signs of disease included whirling, pale gills, watery colourless blood, discoloured livers, pathog-nomonic magenta erythrocytic inclusion bodies and histopathological changes consistent with other infectious haemolytic anaemias in higher animals. Transmission electron microscopy confirmed the presence of iridovirus-type particles associated with the cytoplasmic erythrocytic inclusion bodies. Other apparently healthy herring of various age classes from four additional areas in south-east Alaska also had clinical signs of VEN suggesting a wide distribution of the virus in Alaskan Pacific herring populations. Evidence regarding the two herring epizootics indicated that osmoregulatory stress may have precipitated mortalities in fish having severe anaemia caused by the VEN virus. This is the first reported occurrence of VEN in Alaska and the first natural epizootic known to be associated with the disease.

Electronic Resource

1365-2761

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

Abstract. The prevalence of a chlamydial infection in hatchery-reared adult hard clams Mercenaria mercenaria (L.) from Great South Bay, Long Island, New York was relatively high and seasonally stable. Infection occurred early in life while juvenile clams were still within the hatchery. Fluorescent antibody tests suggested that the clam agent shares the group antigen specific for chlamydia, but to a lesser degree than a known chlamydial strain used as a positive control. The method of Gimenez failed to stain elementary bodies in clam cell inclusion bodies. Based on the observations of this study, the inclusion body agent in the hard clam differs from known strains of chlamydia. Characterization of the clam chlamydia must await the successful propagation of the agent.

Electronic Resource

1365-2761

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

Epizootic mortalities of returning adult Rogue River fall chinook salmon, Oncorhynchus tshawytscha (Walbaum), were first observed in 1978. These mortalities reached approximately 76% in 1979 and declined to 30--50% in 1980 and less than 10% in 1981 and 1982. Histopathological examination of kidneys from moribund returns in 1981 and 1982 showed a diffuse chronic glomerulonephritis (GN) in 83% and 30% of the fish examined, respectively. In most cases glomerular damage was severe enough to cause morbidity from osmoregulatory failure. The lesion was markedly similar to immune complex-mediated glomerular disease in higher vertebrates, but tissues for further ultrastructural examination and diagnosis were not processed. Giemsa-stained sections also revealed unidentified sporozoan-like vegetative stages encysted within the extracellular mesangial matrix of glomeruli in both GN and normal kidneys. Although probably incidental to the glomerular lesion, the causal relationship of the organism to GN remains unknown until further investigation. Glomeruli of outmigrating Rogue River fall chinook salmon smolts collected in 1983 were normal and free of the organism.

Electronic Resource

1365-2761

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

Abstract. Gross and histological descriptions of four different spontaneous neoplasms in three species of salmonid fishes are provided: thymic lymphoma and dermal fibrosarcoma, respectively, in two artificially reared sockeye salmon, Oncorhynchus nerka (Walbaum); renal papilliferous cystadenoma in a wild caught chinook salmon, O. tshawytscha (Walbaum); capillary haemangioma of the dermis in an artificially reared rainbow trout, Salmo gairdneri Richardson. The frequency of occurrence of these and related tumour types, as reported in the literature, are compared in salmonid and non-salmonid fish.

Electronic Resource

1365-2761

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

Abstract. A viral agent (13p2), isolated from clinically normal juvenile American oysters (Crassostrea virginica) and characterized as a new serotype of reovirus, was tested to determine if it could replicate and produce disease in experimental juvenile oysters. Because the virus replicated well in the bluegill fry (BF-2) fish cell line, fingerling bluegills Lepomis macrochirus were included in the pathogenicity experiments. Exposure of oysters to the 13p2 virus in ambient seawater resulted in no significant mortality and no increased virus titres or histological lesions. Virus particles were not observed in tissues of exposed oysters when examined with transmission electron microscopy (TEM). Intraperitoneal inoculation of the 13p2 virus into bluegills resulted in 44% mortality associated with a focal necrotic hepatitis. Evidence of virus replication, when evaluated histological or by virus titration, was observed in 94% of 32 inoculated fish. Samples of infected livers examined with TEM revealed typical cytoplasmic arrays of 13p2 virus particles in affected hepatocytes. Rising virus titres and hepatic lesions also occurred in bluegills exposed to water containing the 13p2 virus. These results indicated the natural host of the 13p2 virus was not the American oyster, but that it was a significant pathogen for at least one fish species.

Electronic Resource

1365-2761

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

Abstract. Both fingerling and adult rainbow trout were given intraperitoneal inoculations of the 131P2 reovirus which did not result in mortalities but produced a subclinical disease in 56% of the adults and in 65% of the juvenile fish. Sera from virus infected adult trout contained virus neutralizing and precipitating antibodies and demonstrated immunofluorescence of antigen(s) specific for the 13P2 virus. Virus infection was characterized by increased virus titres and a multifocal reticulo-endothelial granulomatous hepatitis, occasionally accompanied by a fibrosing pancreatitis. Electron microscopy of infected liver tissues demonstrated arrays of 13P2 virus particles in a reticuloendothelial cell phagosome and in a hepatocyte lipid inclusion body from one of three juvenile fish examined. These results show that 13P2 virus inoculation of rainbow trout causes a non-virulent virus infection accompanied by specific humoral antibodies. These antibodies are sufficient in titre for use in future serologic studies of the virus. Further discussion regarding the pathogenesis of this virus in bluegills versus rainbow trout is presented.

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] Apart from these widely recognized modes of transmission, no other possibilities have been considered seriously1. But Schaperclaus2 found myxosporidiari spores in the faeces of kingfishers at an infected hatchery and believed that the disease could be spread in this manner. His observations are ...

Electronic Resource

1573-2959

Springer Online Journal Archives 1860-2000

Energy, Environment Protection, Nuclear Power Engineering

Abstract An objective methodology presented in a companion paper (Liu et al., 1986) for determining the optimum number and disposition of ambient air quality stations in a monitoring network for carbon monoxide is applied to the Las Vegas, Nevada, area. The methodology utilizes an air quality simulation model to produce temporally-varying air quality patterns for each of a limited number of meteorological scenarios representative of the region of interest. These air quality patterns in turn serve as the data base in a two-step procedure for the identification and ranking of the most desirable monitoring locations (step 1) and the removal of redundancies in spatial coverage among the desired locations (step 2.) The performance of the air quality simulation model, a key element in the design methodology, was evaluated in the Las Vegas area in a special field measurement program. In the Las Vegas demonstration for carbon monoxide, 19 stations covering concentration maxima and 3 stations covering background concentrations in rural areas were identified and ranked. A 10-station network, for example, consisting of 7 stations for peak average concentrations and 3 stations for background concentrations, was selected for a desired minimum detection capability of 50% of concentration variations. Networks with fewer stations would be selected if smaller minimum detection capabilities of concentration variations are acceptable, and vice versa. Background stations could, of course, be deleted for networks with the sole purpose of discerning peak concentrations.

Electronic Resource

1573-1472

Springer Online Journal Archives 1860-2000

Geosciences

Physics

Abstract The deposition velocity (V d) of nitric acid vapor over a fully leafed deciduous forest was estimated using flux/gradient theory. HNO3 deposition velocities ranged from 2.2 to 6.0cm/s with a mean V don the order of 4.0cms-1. Estimates of V dfrom a detailed canopy turbulence model gave deposition velocities of similar magnitude. The model was used to investigate the sensitivity of V dto the leaf boundary-layer resistance and leaf area index (LAI). Although modeled deposition velocities were found to be sensitive to the parameterization of the leaf boundary-layer resistance, they were less sensitive to the LAI. Modeled V d's were found to peak at LAI = 7.

Electronic Resource

1573-0662

Methane ; carbon dioxide ; flux ; landfill ; diode laser ; eddy correlation

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Geosciences

Abstract We describe a fast response methane sensor based on the absorption of radiation generated with a near-infrared InGaAsP diode laser. The sensor uses an open path absorption region 0.5 m long; multiple pass optics provide an optical path of 50 m. High frequency wavelength modulation methods give stable signals with detection sensitivity (S/N=1, 1 Hz bandwidth) for methane of 65 ppb at atmospheric pressure and room temperature. Improvements in the optical stability are expected to lower the current detection limit. We used the new sensor to measure, by eddy correlation, the CH4 flux from a clay-capped sanitary landfill. Simultaneously we measured the flux of CO2 and H2O. From seven half-hourly periods of data collected after a rainstorm on November 23, 1991, the average flux of CH4 was 17 mmol m−2 hr−1 (6400 mg CH4 m−2 d−1) with a coefficient of variation of 25%. This measurement may underrepresent the flux by 15% due to roll-off of the sensor response at high frequency. The landfill was also a source of CO2 with an average flux of 8.1 mmol m−2 hr−1 (8550 mg CO2 m−2 d−1) and a coefficient of variation of 26%. A spectral analysis of the data collected from the CH4, CO2, and H2O sensors showed a strong similarity in the turbulent transfer mechanisms.

Electronic Resource

1573-2932

Springer Online Journal Archives 1860-2000

Energy, Environment Protection, Nuclear Power Engineering

Abstract Because there is no simple device capable of measuring the dry deposition rates of small particles and trace gases directly, much current activity is focused on the use of an inferential technique. In this method, measurements of atmospheric concentration (C) of selected chemical species are coupled with evaluations of appropriate deposition velocity (V d ) to yield estimates of dry deposition rate from their product. Difficulties arise concerning the ability to measure C, and especially regarding the poor knowledge of V d for many species. A multiple resistance routine for deriving deposition velocities is presented here. Current knowledge of biological processes is incorporated into a first-generation lsbig leaf’ model; formulations of resistances appropriate for describing individual leaves are combined to simulate the canopy as a whole. The canopy resistance is combined with estimates of aerodynamic and boundary-layer resistances to approximate the total resistance to transfer, from which deposition velocity is then computed. Special emphasis is given to the influence of the diurnal cycle, to the way in which the various transfer resistances can be inferred from routine data, and to the role of canopy factors (e.g., leaf area index, wetness, temperature response, and sunshade fractions).

Electronic Resource

1573-2932

Springer Online Journal Archives 1860-2000

Energy, Environment Protection, Nuclear Power Engineering

Abstract Aerosol and total vapor-phase Hg concentrations in air have been measured at Walker Branch Watershed, Tennessee for ≈ 2 yr. Airborne Hg at this site is dominated by vapor forms which exhibit a strong seasonal cycle, with summer maxima that correspond to elevated air temperature. Concentrations in this forest are near background levels; however, concentrations at a site within 3 km are significantly elevated due to emissions from Hg-contaminated soils. The concentration data have been combined with a recently modified dry deposition model to estimate dry deposition fluxes to the deciduous forest at Walker Branch. Weekly mean modeled Vd values for Hg° ranged from 〈0.01 (winter) to 〉 0.1 (summer) cm s1. Weekly dry deposition fluxes ranged from 〈0.1 µg m−2 during winter to 〉 1.0 µgg m−2 in the summer. Our dry deposition estimates plus limited measurements of wet deposition in this area indicate that dry deposition may be the dominant input process in this forest, at least during the summer.

Electronic Resource

1573-2932

Springer Online Journal Archives 1860-2000

Energy, Environment Protection, Nuclear Power Engineering

Abstract Mercury is emitted from soil and water surfaces, but few actual direct flux measurements have been reported. During June, 1994 we performed the first micrometeorological measurements of Hg vapor fluxes over a boreal forest lake. Using highly precise methods with multiple replicate samplers, we measured concentration gradients of Hg vapor, CO2 and H2O over the lake surface. Mercury was readily emitted from the lake surface, and we found no evidence of Hg dry deposition to the lake. Emission rates over the lake averaged 8.5 ng m2 h−1, and appeared to be weakly influenced by water temperature and solar radiation. These fluxes were somewhat higher than those previously measured using surface chambers at this site.

Electronic Resource