Inheritance of resistance to bacterial wilt in tobacco     

SMITH TE  CLAYTON EE 《Journal of agricultural research》1948,76(1):27-32

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Low-level irradiation and threshold shift in the visual receptor     

DAWSON WW  SMITH JC 《Science (New York, N.Y.)》1959,129(3364):1670-1671

Customary methods of stimulating and recording were used to examine threshold shifts of the single visual receptor in the lateral eye of Limulus in response to low-level x-irradiation. Marked visual sensitization was found and was most pronounced at the lowest dosage levels (1 to 25 r). Complete light adaptation apparently cancelled the effects of the irradiation.  相似文献   

Motor responses of moths to low-intensity x-ray exposure     

SMITH JC  KIMELDORF DJ  HUNT EL 《Science (New York, N.Y.)》1963,140(3568):805-806

A brief burst of x-rays elicited flight activity in moths placed in a darkened x-ray exposure room. Wing-beat activity was recorded as an index of this behavior. Wing-beat activity could be initiated in resting moths or amplitude augmented in active moths by x-ray dose rates of 0.01 to 1.5 roentgens per second, with a latency of less than 1 second after onset of exposure.  相似文献   

Sexuality in Chlamydomonas     

SMITH GM 《Science (New York, N.Y.)》1948,108(2816):680

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Protective effect of a colchicine derivative in mice exposed to x-radiation     

SMITH WW 《Science (New York, N.Y.)》1958,127(3294):340-341

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THE OCCURRENCE OF ETHYLENE IN ANAEROBIC SOIL   总被引：6，自引：0，他引：6  

K. A. SMITH  S. W. F. RESTALL 《European Journal of Soil Science》1971,22(4):430-443

The production of ethylene and other hydrocarbon gases by soils under anaerobic conditions was measured by gas chromatography. Ethylene was the only hydrocarbon gas which occurred in physiologically significant concentrations; more than 20 ppm was found in several soils after 10 days at 20°C. These concentrations were considerably higher than those which were known to cause severe reductions in the extension of root axes of some plant species. Experiments with sterilized and unsterilized soil indicated that ethylene was produced by enzyme activity and not by chemical action. The gas was found in soil when the oxygen concentration fell below 2 per cent; total evolution was correlated with organic matter content, and was affected by drying and rewetting and by the growth of plant roots. The rate of production was increased by raising the temperature and by addition of glucose or peptone; high concentrations of nitrate depressed the rate, but sulphate and phosphate had little effect. It is concluded that ethylene may be a significant factor in causing injury to crop plants under waterlogged conditions and also in situations where anaerobic pockets occur within a mainly aerobic soil structure, provided that escape of the gas from the soil is impeded sufficiently to allow inhibitory concentrations to build up in the vicinity of plant roots.  相似文献   

Gaseous diffusion through peat     

J. A. KING  K. A. SMITH 《European Journal of Soil Science》1987,38(2):173-177

Relative gas diffusivity (D/D₀) was measured in peat cores equilibrated to set moisture tensions between zero and - l0 kPa, using the radioactive gas ⁸⁵Kr. A relationship between relative diffusivity and the air filled porosity was obtained, which showed lower values of D/D₀ at air-filled porosities above about 0.13m³m⁻³, and higher values at porosities below about 0.10m³m⁻³ than some of those found in the literature for mineral soils. The likely effects of shrinkage behaviour on drying in the field, on the relationship between D/D₀ and air-filled porosity, are discussed.  相似文献   

The estimation of mineralization, immobilization and nitrification in nitrogen-15 field experiments using computer simulation     

D. BARRACLOUGH  M. J. SMITH 《European Journal of Soil Science》1987,38(3):519-530

A combination of mathematical analysis and computer simulation, using parameters readily measured in a nitrogen-15 field experiment, is employed to determine rates of mineralization, immobilization and nitrification under a growing crop. The procedure also yields the proportion of crop nitrogen uptake occurring as ammonium and nitrate.
When applied to -results from grass lysimeters receiving 250 or 900 kg N ha^–1 a^–1 as ammonium nitrate, the analysis suggested that at 250 kgN ha^–1 a^–1 64–66% of crop nitrogen uptake was as ammonium; at 900 kg N ha^–1 a^–1 the figure was 43–49%. Nitrification at 250kgNha^–1 was only 13–19kgN ha^–1 over 160d while at 900 kg N ha^–1 between 191 and 232 kg N ha^–1 were nitrified.
The results suggested that the apparent inhibition of nitrification in grassland soils may simply reflect poor substrate competition by nitrifying bacteria. Finally, there was a suggestion that mineralization/immobilization was lower at the high fertilizer rate.  相似文献   

Volvulus of the Distal Part of the Jejunoileum in Four Cows     

S. L. FUBINI dvm    D. F. SMITH dvm  Diplomateacvs    P. K. TITHOF dvm    J. A. PERDRIZET dvm  W. C. REBHUN dvm  Dipiomateacvimacvo 《Veterinary surgery : VS》1986,15(2):150-152

Four cows were diagnosed as having volvulus of the distal jejunoileum. Affected cattle became acutely depressed, dehydrated, and tachycardic, all developed abdominal distention, and three of four were in severe pain at the time of admission. Feces were scant or absent. The volvulus was corrected by exteriorizing the small intestine and replacing it in correct position. All four cows recovered without complications and were well 6 months or more following surgery.  相似文献   

The Medial Saphenous Fasciocutaneous Free Flap in Dogs     

DANIEL A. DEGNER DVM    RICHARD WALSHAW BVMS  Diplomate ACVS    OTTO LANZ DVM    DIANA ROSENSTEIN DVM  RICK J. SMITH MD 《Veterinary surgery : VS》1996,25(2):105-113

The purpose of this study was to identify the angiosome of the medial saphenous artery and vein and to evaluate the use of this cutaneous angiosome as a free skin flap in the dog. In phase 1 of this study, selective angiography of the medial saphenous artery performed in six canine cadavers showed that the skin covering the entire medial femorotibial area, the distal half of the caudal head of the sartorius muscle, and the gracilis muscle were perfused by the medial saphenous artery. In phase 2, a medial saphenous fasciocutaneous island flap was raised and sutured back to the skin edges of the donor wound in three dogs. One hundred percent survival of all of the flaps occurred. In phase 3, a medial saphenous fasciocutaneous microvascular free flap was transferred to a wound that was created over the dorsal metacarpal (n = 3) or metatarsal region (n = 3). The mean length ± SD of the medial saphenous vascular pedicle was 80 ± 13 mm (n = 5); the mean diameter ± SD of the medial saphenous artery was 2.8 ± 0.2 mm (n = 5) and the mean diameter ± SD of the medial saphenous vein was 4.2 ± 0.2 mm (n = 5). One hundred percent of all flaps survived (n = 6). Selective angiography of the distal cranial tibial artery (metatarsal wounds, n = 3) and the median artery (metacarpal wound, n = 3) was performed 3 weeks after surgery. All of the vascular anastomoses were patent and neovascularization of the wound beds was present. This free flap was found to be acceptable for cosmetic reconstruction of wounds located on the distal extremity.  相似文献