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1,3‐Dichloropropene (1,3‐D), which consists of two isomers, (Z)‐ and (E)‐1,3‐D, is considered to be a viable alternative to methyl bromide, but atmospheric emission of 1,3‐D is often associated with deterioration of air quality. To minimize environmental impacts of 1,3‐D, emission control strategies are in need of investigation. One approach to reduce 1,3‐D emissions is to accelerate its degradation by incorporating organic amendments into the soil surface. In this study, we investigated the ability of four organic amendments to enhance the rate of degradation of (Z)‐ and (E)‐1,3‐D in a sandy loam soil. Degradation of (Z)‐ and (E)‐1,3‐D was well described by first‐order kinetics, and rates of degradation for the two isomers were similar. Composted steer manure (SM) was the most reactive of the organic amendments tested. The half‐life of both the (Z)‐ and (E)‐isomers in unamended soil at 20 °C was 6.3 days; those in 5% SM‐amended soil were 1.8 and 1.9 days, respectively. At 40 °C, the half‐life of both isomers in 5% SM‐amended soil was 0.5 day. Activation energy values for amended soil at 2, 5 and 10% SM were 56.5, 53.4 and 64.5 kJ mol?1, respectively. At 20 °C, the contribution of degradation from biological mechanisms was largest in soil amended with SM, but chemical mechanisms still accounted for more than 58% of the (Z)‐ and (E)‐1,3‐D degradation. The effect of temperature and amendment rate upon degradation should be considered when describing the fate and transport of 1,3‐D isomers in soil. Use of organic soil amendments appears to be a promising method to enhance fumigant degradation and reduce volatile emissions. Published in 2001 for SCI by John Wiley & Sons, Ltd 相似文献
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House flies were collected from dairies across New York state and the levels of resistance to seven insecticides were measured using standard laboratory assays with three to five diagnostic concentrations. The highest levels of resistance were found for tetrachlorvinphos, permethrin and cyfluthrin. Although levels of resistance to methomyl were somewhat lower, they were among the highest ever reported for field‐collected house flies. Resistance to pyrethrins was limited primarily to the lowest diagnostic concentration. House flies were susceptible to fipronil at all dairies, suggesting that this material would be highly effective for fly control. The levels of resistance were similar at all the dairies, irrespective of their insecticide use, suggesting substantial movement of flies between facilities. Relative to resistance levels found at New York dairies in 1987, resistance levels had increased for permethrin, were unchanged for tetrachlorvinphos and had decreased for dimethoate. To identify a single diagnostic concentration that could be used in the laboratory assays to assess accurately resistance levels in future studies, we carried out a ‘simulated’ field bioassay using formulated materials. A diagnostic concentration for each insecticide is proposed on the basis of a comparison of our bioassays. © 2001 Society of Chemical Industry 相似文献
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Scott J. Nissen Robert A. Masters W. Mack Thompson Robert N. Stougaard 《Pest management science》1995,45(4):325-329
Imazapyr absorption, translocation, root release and metabolism were examined in leafy spurge (Euphorbia esula L.). Leafy spurge plants were propagated from root cuttings and [14C]imazapyr was applied to growth-chambergrown plants in a water + 28% urea ammonium nitrate + nonionic surfactant solution (98.75 + 1 + 0.25 by volume). Plants were harvested two and eight days after herbicide treatment (DAT) and divided into: treated leaf, stem and leaves above treated leaf, stem and leaves below the treated leaf, crown, root, dormant and elongated adventitious shoot buds. Imazapyr absorption increased from 62.5% 2 DAT to 80.0% 8 DAT. Herbicide translocation out of the treated leaf and accumulation in roots and adventitious shoot buds was apparent 2 DAT. By the end of the eight-day translocation period only 14% of applied 14C remained in the treated leaf, while 17% had translocated into the root system. Elongated and dormant adventitious shoot buds accumulated 3.2- and 1.8-fold more 14C, respectively, 8 DAT than did root tissue based on Bq g?1 dry weight. Root release of 14C was evident 2 DAT, and by 8 DAT 19.4% of the 14C reaching the root system was released into the rooting medium. There was no metabolism of imazapyr in crown, root or adventitious shoot buds 2 DAT; however, imazapyr metabolism was evident in the treated leaf 2 and 8 DAT. Imazapyr phytotoxicity to leafy spurge appears to result from high imazapyr absorption, translocation to underground meristematic areas (roots and adventitious shoot buds), and a slow rate of metabolism. 相似文献
55.
The object of this study was to develop a simple method for accurately calculating the volume of bovine claws under field conditions. The digits of 30 slaughterhouse beef cattle were examined and the following four linear measurements taken from each pair of claws: (1) the length of the dorsal surface of the claw (Toe); (2) the length of the coronary band (CorBand); (3) the length of the bearing surface (Base); and (4) the height of the claw at the abaxial groove (AbaxGr). Measurements of claw volume using a simple hydrometer were highly repeatable (r(2)= 0.999) and could be calculated from linear measurements using the formula:Claw Volume (cm(3)) = (17.192 x Base) + (7.467 x AbaxGr) + 45.270 x (CorBand) - 798.5This formula was found to be accurate (r(2)= 0.88) when compared to volume data derived from a hydrometer displacement procedure. The front claws occupied 54% of the total volume compared to 46% for the hind claws. 相似文献
56.
Karp BE Ball NE Scott CR Walcoff JB 《Journal of the American Veterinary Medical Association》1999,215(12):1824-7, 1806
Two privately owned domestic rabbits (Oryctolagus cuniculus) in Maryland were found to be infected with the raccoon variant of the rabies virus in 1998. Both rabbits had an acute onset of anorexia and paralysis or paresis of the left forelimb; 1 also developed head tremors and a head tilt. One of the rabbits became ill 25 days after being attacked by a raccoon (Procyon lotor) and was euthanatized 3 days after onset of illness. The other rabbit, which was housed in an outdoor hutch, died 4 days after onset of clinical signs; the source of infection in that rabbit remains unknown. Currently, there is not a rabies vaccine approved for use in rabbits; thus, the only way to prevent the infection in rabbits is to prevent exposure. Veterinarians in rabies-enzootic areas should be familiar with the clinical signs of rabies in rabbits and should caution rabbit owners about the need to protect their pets from contact with wildlife. 相似文献
57.
Intervertebral 7.5 mm (n = 75) and 6.0 mm (n = 22) metal washers were used to distract intervertebral spaces in 78 consecutive cases of canine cervical spondylopathy-associated disc protrusions, where myelography had demonstrated traction-responsive spinal cord compression. Nineteen dogs had compressive lesions at two sites. Fifty lesions were evaluated myelographically on immediate postoperative radiographs; of these, 32 compressions had been eliminated and 18 had been reduced. Euthanasia was performed in nine dogs within six months of surgery and 15 dogs had varying degrees of neck pain during this period. Long-term follow-up information was available on 65 dogs nine to 70 months following surgery (median 32 months). Sixty-three of these dogs improved postoperatively. Neurological function subsequently deteriorated in 17 dogs 10 to 59 months following surgery (median 34 months). Eight of these 17 cases had further myelographic investigations and all had additional disc protrusions with no evidence of cord compression at the previous sites of surgery. The remaining nine cases had a deterioration in hindlimb function but were not investigated further. 相似文献
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