The potato association of America loses a loyal member     

W. Stuart 《American Journal of Potato Research》1932,9(6):98-98

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The influence of salmon surface mucus on the growth of Flavobacterium columnare     

Staroscik AM  Nelson DR 《Journal of fish diseases》2008,31(1):59-69

Flavobacterium columnare is the causative agent of columnaris disease. The presence of lesions on the gills, skin and fins of diseased fish suggests that F. columnare is able to utilize fish skin mucus as a substrate for growth and that exposure to this material would alter the expression of genes involved in the colonization of the outer surfaces of the fish. Growth, biofilm formation, extracellular protease production and changes in protein expression of F. columnare strain C#2 cultured in media supplemented with juvenile Atlantic salmon skin mucus were compared with the same media without mucus. C#2 was able to grow by using mucus as the sole nutrient source. Growth in mucus-containing media induced cells to grow as a biofilm and extracellular protease activity increased in mucus-containing cultures. SDS-PAGE protein profiles showed that expression of six extracellular proteins increased in mucus-containing media. These results demonstrate that salmon surface mucus promotes the growth of F. columnare and that exposure to mucus alters the growth characteristics of this bacterium with regard to protease production and biofilm formation. Further characterization of mucus-induced physiological changes will increase our understanding of the basis of virulence of this economically important fish pathogen.  相似文献   

Evaluating the effects of supplementing Saccharomyces cerevisiae in the feed or drinking water on stress susceptibility of broilers     

E.B. Sobotik  J.R. Nelson  H.O. Pavlidis  G.S. Archer 《The Journal of Applied Poultry Research》2022,31(1):100220

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Heats of transfer and activation energy for bound water diffusion in wood     

Ralph M. Nelson Jr. 《Wood Science and Technology》1991,25(3):193-202

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Emergence timing affects root-collar diameter and mortality in loblolly pine seedbeds     

James N. Boyer  Stuart E. Duba  David B. South 《New Forests》1987,1(2):135-140

Eight half-sib families of loblolly pine (Pinus taeda L.) were sown in a nursery. Total germination, speed and uniformity of germination, root-collar diameters, mortality, and percent cull were recorded by family. Families which germinated quickest attained the greatest average diameters at the end of the growing season. Low variability in date of emergence led to correspondingly low variability in seedling diameter. When data for all families were combined, seedlings which emerged earliest experienced the lowest mortality, had the largest diameters, and produced the fewest culls.  相似文献   

Examination of stand structure on quail plantations in the Red Hills region of Georgia and Florida managed by the Stoddard-Neel system: an example for forest managers   总被引：1，自引：0，他引：1  

Moser  W. Keith; Jackson  Stuart M.; Podrazsky  Vilem; Larsen  David R. 《Forestry》2002,75(4):443-449

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Comparison of image and rapid field assessments of riparian zone condition in Australian tropical savannas     

Kasper Johansen  Stuart Phinn  Ian Dixon  Michael Douglas  John Lowry 《Forest Ecology and Management》2007,240(1-3):42-60

Suitable methods for measuring and monitoring the condition of riparian environments are being investigated by government agencies responsible for maintaining these environments in Australia. The objective of this work was to compare two riparian condition assessment approaches, the Tropical Rapid Appraisal of Riparian Condition (TRARC) method developed for rapid on-ground assessment of the environmental condition of savanna riparian zones and an image based riparian condition monitoring scheme. Measurements derived from these two approaches were compared and correlated. The sample representativeness of the TRARC method was evaluated and the cost-effectiveness and suitability for multi-temporal analysis of the two approaches were assessed. Two high spatial resolution multi-spectral QuickBird satellite images captured in 2004 and 2005 and coincident field data covering sections of the Daly River in the Northern Territory, Australia were used in this work. Both field and image data were processed to map indicators of riparian zone condition including percentage canopy cover, organic litter on the ground, canopy continuity, tree clearing, bank stability, and flood damage. Spectral vegetation indices, image segmentation, and supervised classification were used to produce riparian health indicator maps. QuickBird image data were used to examine if the spatial distribution of TRARC transects provided a representative sample of ground based estimates of riparian health indicators. Covering approximately 3% of the study area, the sample mean of the TRARC estimates of individual indicators of riparian zone condition were in most cases within 20% of the global mean derived from the whole imaged riparian area. The cost-effectiveness of the image based approach was compared to that of the ground based TRARC method. Results showed that the TRARC method was more cost-effective at spatial scales from 1 km to 200 km of river in relatively homogeneous riparian zones along rivers with only one channel, while image based assessment becomes more feasible at regional scales (200–2000 km of river). A change detection analysis demonstrated that image data can provide detailed information on gradual change, while the TRARC method is less suited for multi-temporal analysis due to the ranked data format, which inhibits precise detection of change. However, results from both methods were considered to complement each other for single date assessment of riparian zones if used at appropriate spatial scales.  相似文献   

Diffusion of bound water in wood     

R. M. Nelson Jr. 《Wood Science and Technology》1986,20(4):309-328

Summary Choong's (1963) data for isothermal sorption of water vapor by wood are used to compute pressures, chemical potentials, and entropies of water in the wood specimens of his nonisothermal mass equilibrium experiments. Entropies of both the bound water and water vapor were reasonably constant. A balance existed between thermal diffusion and mass diffusion, as indicated by gradients in temperature and chemical potential. This balance also is suggested by opposing gradients in spreading pressure and vapor pressure. Equal chemical potentials showed that the vapor and bound water were in equilibrium. The model proposed by Siau (1980) for nonisothermal diffusion is consistent with these results. Expressions are given for the two unknown parameters in this model: moisture conductivity and heat of transfer. The constant entropy of water vapor is used to show that the heat of transfer exceeds the activation energy for bound water diffusion by about 25 percent.The author wishes to thank Dr. Christen Skaar for his helpful comments during preparation of this paper for publication  相似文献   

Community Perspective on State Forest Management Regime and its Implication on Forest Sustainability: A Case Study of Chobe Forest Reserve,Botswana     

Hesekia Garekae  Joyce Lepetu  Olekae T Thakadu  Venus Sebina  Nelson Tselaesele 《Journal of Sustainable Forestry》2020,39(7):692-709

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Versatility of the Angularis Oris Axial Pattern Flap for Facial Reconstruction          下载免费PDF全文

Sara L. Losinski  Bryden J. Stanley  Sandra P. Schallberger  Laura L. Nelson  Heather A.M. Towle Millard 《Veterinary surgery : VS》2015,44(8):930-938

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