Field application of industrial by-products as Al toxicity amendments: chemical and mineralogical implications   总被引：1，自引：0，他引：1  

V. Illera  F. Garrido  C. Vizcayno  & M. T. García-González 《European Journal of Soil Science》2004,55(4):681-692

Lime, gypsum and various gypsum‐like by‐products have long been applied to soil surfaces as ameliorants of soil acidity and aluminium and manganese toxicity. We examined changes in chemical and mineralogical properties at two different depths in two acid soils one year after the application of gypsum, phosphogypsum + dolomitic residue, red gypsum + dolomitic residue, sugar foam, and sugar foam + mined gypsum. All treatments were found to increase the proportion of Ca²⁺ and decrease those of Al³⁺ and Mn²⁺ in the exchange complex of the surface and subsurface horizons, thus reducing its effective Al and Mn saturation. However, the mined gypsum treatment resulted in losses of Mg²⁺ from the Ap horizon of the soils, and the sugar foam treatment was not so effective with the AB horizons as the other treatments. The combined application of both gypsum‐like by‐products and the dolomitic residue proved the most effective choice with a view to reducing the effective Al and Mn saturation of the exchange complex in the Ap and AB horizons. In addition, both treatments reduced Mg²⁺ losses at both depths. Finally, all treatments resulted in the formation and retention on mineral and organic surfaces of a large fraction of the Al³⁺ released by exchange with Ca²⁺ as Al polymers. This is quite consistent with the observed changes in the CuCl₂‐, oxalate‐ and DTPA‐extractable Al contents as well as by SEM and EDS analyses. Based on these results, the use of the appropriate mixtures of these by‐products is an effective alternative to that of mined gypsum and lime to alleviate soil acidity and reduce toxic concentrations of Al³⁺ and Mn²⁺ in agricultural acid soils.  相似文献   

Verotoxin-producing Escherichia coli from the faeces of sheep, calves and pigs   总被引：4，自引：0，他引：4  

H. SIDJABAT-TAMBUNAN  JC BENSINK 《Australian veterinary journal》1997,75(4):292-293

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Closantel resistance in Huemonchus contortus from sheep     

PF ROLFE  JC BORAY  C. FITZGIBBON  G. PARSONS  P. KEMSLEY  N. SANGSTER 《Australian veterinary journal》1990,67(1):29-31

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Phenylbutazone in racing Greyhounds: plasma and urinary residues 24 and 48 hours after a single intravenous administration     

PC MILLS  JC NG†  KV SKELTON†  AA SEAWRIGHT  DE AUER† 《Australian veterinary journal》1995,72(8):304-308

SUMMARY The concentrations of phenylbutazone (PBZ), oxyphenbutazone (OPBZ) and gammahydroxyphenylbutazone (OHPBZ) in plasma and urine from 50 Greyhounds 24 and 48 h after the intravenous administration of a single dose of PBZ (30 mg/kg) were measured. The 24 h plasma concentrations of OPBZ and OHPBZ, the 48 h plasma concentration of OHPBZ and the 24 h urinary concentration of PBZ were normally distributed, while log transformations were required before the 24 h plasma concentration of PBZ and the 24 and 48 h urinary concentrations of OPBZ and OHPBZ became normally distributed. The 95%, 99%, 99.9% and 99.99% upper predicted confidence intervals for both 24 h and 48 h plasma and urinary concentrations demonstrated wide potential variation in the concentration of the analytes should PBZ be administered to Greyhounds. The 24 h plasma and urinary concentrations of PBZ were weakly correlated, but no similar relationship existed for OPBZ or OHPBZ. The urinary concentrations of each analyte were not affected by the trainer or sex of the Greyhound or the urinary pH. We conclude that it would be impossible to predict the timing of the PBZ administration or the plasma concentration of PBZ from the measurement of the concentration of PBZ in a single sample of urine.  相似文献   

Organic carbon fluxes and ecological recovery from the cretaceous-tertiary mass extinction     

S D'Hondt  P Donaghay  JC Zachos  D Luttenberg  M Lindinger 《Science (New York, N.Y.)》1998,282(5387):276-279

Differences between the carbon isotopic values of carbonates secreted by planktic and benthic organisms did not recover to stable preextinction levels for more than 3 million years after the Cretaceous-Tertiary mass extinction. These decreased differences may have resulted from a smaller proportion of marine biological production sinking to deep water in the postextinction ocean. Under this hypothesis, marine production may have recovered shortly after the mass extinction, but the structure of the open-ocean ecosystem did not fully recover for more than 3 million years.  相似文献   

Photonic band gap guidance in optical fibers   总被引：3，自引：0，他引：3  

JC Knight  J Broeng  TA Birks  PSJ Russell 《Science (New York, N.Y.)》1998,282(5393):1476-1478

A fundamentally different type of optical waveguide structure is demonstrated, in which light is confined to the vicinity of a low-index region by a two-dimensional photonic band gap crystal. The waveguide consists of an extra air hole in an otherwise regular honeycomb pattern of holes running down the length of a fine silica glass fiber. Optical fibers based on this waveguide mechanism support guided modes with extraordinary properties.  相似文献   

Room temperature-operating spin-valve transistors formed by vacuum bonding     

DJ Monsma  R Vlutters  JC Lodder 《Science (New York, N.Y.)》1998,281(5375):407-409

Functional integration between semiconductors and ferromagnets was demonstrated with the spin-valve transistor. A ferromagnetic multilayer was sandwiched between two device-quality silicon substrates by means of vacuum bonding. The emitter Schottky barrier injected hot electrons into the spin-valve base. The collector Schottky barrier accepts only ballistic electrons, which makes the collector current very sensitive to magnetic fields. Room temperature operation was accomplished by preparing Si-Pt-Co-Cu-Co-Si devices. The vacuum bonding technique allows the realization of many ideas for vertical transport devices and forms a permanent link that is useful in demanding adhesion applications.  相似文献   

Successful Treatment for Subinvolution of Placental Sites in the Bitch with Low Oral Doses of Progestagen     

MJ Voorhorst  JC van Brederode  CHJ Albers‐Wolthers  J de Gier  AC Schaefers‐Okkens 《Reproduction in domestic animals》2013,48(5):840-843

Subinvolution of placental sites (SIPS) is the major cause of persistent sanguineous vaginal discharge after parturition in the bitch. Spontaneous remission is common but may take several months, and hence, medical therapy to end the discharge is often requested. In this retrospective study, we evaluated the effect of treatment for SIPS with low oral doses of a progestagen. Nine bitches with SIPS, but otherwise clinically healthy, were found in the computer database of the Department of Clinical Sciences of Companion Animals. Seven of these bitches were treated with low oral doses of a progestagen (megestrol acetate, 0.1 mg/kg body weight (bw) once daily for the 1st week, then 0.05 mg/kg bw once daily for the 2nd week). The other two bitches were untreated. Treatment results were evaluated by a telephone questionnaire. Progestagen treatment was successful in all of the treated dogs; sanguineous vaginal discharge stopped within the treatment period. One of the two untreated dogs remained symptomatic until the next oestrus, approximately 120 days after parturition, and the other remained symptomatic until 6 weeks before the start of the next pro‐oestrus, 270 days after parturition. No side effects of the progestagen treatment were observed. Subsequent gestations, parturitions and puerperal periods of 5 mated bitches were uneventful. One bitch did not become pregnant after mating. In conclusion, the results of this study indicate that oral administration of low doses of progestagen for 2 weeks is effective in stopping persistent sanguineous vaginal discharge in bitches with SIPS, with neither side effects nor reduced subsequent fertility.  相似文献   

Temporal Relationships and Repeatability of Follicle Diameters and Hormone Concentrations within Individuals in Mares     

JC Jacob  EL Gastal  MO Gastal  GR Carvalho  MA Beg  OJ Ginther 《Reproduction in domestic animals》2009,44(1):92-99

Data were collected daily from 23 mares during two consecutive interovulatory intervals (IOIs). Several significant (p < 0.05) new observations on temporal relationships were made. The FSH increase that begins before ovulation temporarily plateaued on the day of discharge of follicular fluid into the peritoneal cavity in association with ovulation. During the declining portion of the pre-ovulatory oestradiol surge, an abrupt reduction in the rate of decrease occurred in synchrony with the peak of the LH surge and is consistent with a negative effect of LH on oestradiol. Repeatability within mares was based on the following positive and significant correlations between the two IOIs: (i) length of the interval between ovulations and between ovulation and the beginning of follicle deviation; (ii) diameter of the pre-ovulatory follicle on days -3 to -1; (iii) number of follicles in diameter classes of 2–5 mm (correlation for 22/23 days of the IOI), 5.1–10 mm (18/23 days), 10.1–15 mm (12/23 days) and 15.1–20 mm (12/23 days) and (iv) concentrations of FSH (18/23 days) and LH (22/23 days). The greatest repeatability for the follicle-diameter classes occurred in the 2–5 mm class, and thereafter the repeatability progressively decreased as the diameters for the classes increased. Results demonstrated measurable repeatability within mares for several end points between consecutive IOIs.  相似文献   

Recovery and Cryopreservation of Epididymal Sperm of Plains Bison (Bison bison bison) as a Model for Salvaging the Genetics of Wood Bison (Bison bison athabascae)     

LC Aurini  DP Whiteside  BT Elkin  JC Thundathil 《Reproduction in domestic animals》2009,44(5):815-822

The objective of this study was to optimize recovery and cryopreservation of epididymal sperm from plains bison, as a model for wood bison. In Phase 1, cauda epididymides were recovered from bison (n = 14) immediately after slaughter, minced and incubated in Sp-TALPH buffer for 3 h at 36°C. The resulting sperm suspensions were cryopreserved in Triladyl^®, using a protocol for bovine semen. In Phase 2, epididymal sperm were cryopreserved in either Triladyl^® or Andromed^®. The mean (±SD) estimated number of sperm recovered was 468 ± 207 × 10⁶. There was an increase (p < 0.05) in the proportion of sperm with normal morphology between initial recovery and after extension (52.4 ± 4.6 vs 69.7 ± 2.4%), with a concurrent decrease (p < 0.05) in the proportion of sperm with distal droplets. Median values for progressively motile sperm in post-thaw samples (60%) were lower (p < 0.05) than that after extension or after chilling (70% for both). The mean percentages of viable sperm and of sperm with an intact acrosome were lower (p < 0.05) for frozen-thawed samples (38.7 ± 2.8 and 85.2 ± 1.1) compared with extended (66.2 ± 2.2 and 92.4 ± 0.9) or chilled (63.7 ± 2.5 and 90.0 ± 1.0) samples. Rates of cleavage, morulae and blastocyst production were not significantly different for chilled (70.9, 38.7 and 8.0%) vs post-thaw sperm (73.0, 46.0 and 6.3%). There was no significant difference between extenders for most sperm characteristics. In conclusion, we developed a functional protocol for the recovery and cryopreservation of epididymal sperm from plains bison, which may have implications for the genetic preservation of wood bison.  相似文献