Competitive interactions between weedy rice and cultivated rice as a function of added nitrogen and the level of competition     

BHAGIRATH S. CHAUHAN  DAVID E. JOHNSON 《Weed Biology and Management》2011,11(4):202-209

The competitive outcomes between weedy rice from Malaysia (MWR), the Philippines (PWR), and Vietnam (VWR) and cultivated rice (IR64) grown in pots were evaluated in a replacement series experiment with added N (0, 50, 100, and 150 kg N ha^?1) and competition with IR64 plants (no competition, eight weedy rice plants : 0 IR64 plants; low competition, six weedy rice plants : two IR64 plants; and high competition, two weedy rice plants : six IR64 plants). The growth observations were taken at 10 weeks after sowing. When grown in a monoculture (no competition with IR64 plants), the PWR plants had a lower shoot biomass across N rates than did the MWR and VWR plants. The leaf area and shoot biomass of weedy rice across populations significantly increased with an increase in the N application rate. Each weedy rice population and the IR64 population showed linear responses of the leaf area and shoot biomass to the N rate at all levels of competition. The weedy rice and IR64 plants, when grown without competition, had a similar rate of response in the shoot biomass to the N rate. However, when grown in competition, the response to the added N varied among the weedy rice populations. The MWR plants under competition produced a similar amount of shoot biomass to the IR64 plants per unit addition of N. In contrast, the PWR and VWR populations under competition produced a greater amount of shoot biomass with each additional unit of N, compared to the IR64 population. The results illustrate that N fertilizer management might affect the outcome of weedy rice competition. This information could be incorporated into weedy rice management strategies.  相似文献   

The Distribution of Bacteria (Other than Staphylococci and Propionibacterium acnes) on the Hair, at the Skin Surface and Within the Hair Follicles of Dogs     

RICHARD G. HARVEY  DAVID H. LLOYD 《Veterinary dermatology》1995,6(2):79-84

Résumé— La distribution des bactéries, autres que les staphlocoques sur la tige des poils, à la surface cutanée et dans les follicules pileux de 8 chiens est analysée. Sur la tige des poils Micrococcus spp. et les bactéries aérobies gram mégatifs sont plus nombreuses avec des numérations variant de 1,12 à 0,84 log₁₀ (colonies formant unites par cm²). Des nombres hautement significatifs (p < 0,05) sont également trouvés. A la surface cutanée Micrococcus spp. des bactéries aérobies gram négatifs et Clostridium sp. sont les plus nombreuses avec des numérations respectives variant de 0,62, 1,12 et 0,84 log₁₀ (colonies formant unités par cm²). Des nombres hautement significatifs (p < 0,05) de Micrococcus spp. sont trouvés de façon plus importante à l'intérieur des follicules pileux qu' à la surface cutanée, les Streptocoques et Bacillus sp. ont été trouvés respectivement sur cinq et quatre chiens. Proteus sp., Pseudomonas sp. Nocardia sp. sont occasion-nellement trouvés. [HARVEY, R.G., LLOYD, D.H. The distribution of bacteria (other than Staphylococci and Propionibacterium acnes) on the hair, at the skin surface and within the hair follicles of dogs (Distribution des bactéries autres que Staphylococci et Propionibacterium acnes) sur le poil, à la surface de al peau et dans les follicules pileux). Resumen— Presentamos la localizatión de bacterias noestafilocócicas en el pelo, en la superficie cutánea y dentro del foliculo piloso de ocho perros. En los pelos, Micrococcus spp. abundantes, con contajes medios entre 1.12 a 0.84 Log₁₀ (unidades formadoras de colonias +1) cm^-1, respectivamente. Se encontró a nivel proximal un número significativamente mayor (p < 0.05) de bacterias aeróbicas gram-negativas y Bacillus spp. En la superficie cutánea, Micrococcus spp., las bacterias aeróbicas contajes medios de 0.62, 1.12 y 0.84 Log₁₀ (unidades formadoras de colonias +1) cm“², respectivamente. Se aisló un número significativamente mayor (p < 0.05) de Micrococcus spp. dentro de los foliculos pilosos que en la superficie cutánea (p < 0.05). Se aisló Streptococi y Bacillus spp. en cinco y cuatro perros, respectivamente. Proteus spp., Pseudomonas spp. y Nocardia spp. fueron hallados ocasionalmente. [HARVEY, R.G., LLOYD, D.H. The distribution of bacteria (other than Staphylococci and Propionibacterium acnes) on the hair, at the skin surface and within the hair follicles of dogs (Localizatión de bacterias (exceptuando Staphilococci y Propionibacterium acnes) en el pelo, en la superficie cutánea y dentro de los foliculos pilosos). Abstract— The distribution of bacteria, other than staphylococci, on the hair shaft, at the skin surface and within the hair follicles of eight dogs is reported. On the hair shafts Micrococcus spp. and aerobic Gram-negative bacteria were most numerous, with mean counts ranging from 1.12 to 0.84 Log₁₀(colony forming units + 1) cm“¹ respectively. Significantly higher numbers (p < 0.05) of Gram-negative bacteria and Bacillus sp. were found proximally. At the skin surface Micrococcus spp., aerobic Gram-negative bacteria and Clostridium spp. were the most numerous with mean counts of 0.62, 1.12 and 0.84 Log₁₀(colony forming units + 1) cm”², respectively. Significantly higher numbers (p < 0.05) of Micrococcus spp. were found within the hair follicles than on the skin surface (p < 0.05). Streptococci and Bacillus spp. were found on five and four dogs, respectively. Proteus spp., Pseudomonas spp. and Nocardia spp. were occasionally found.  相似文献   

Complications of Celiotomy Incisions in Horses     

DAVID A. WILSON DVM  MS  Diplomate ACVS    GORDON J. BAKER BVSc  PhD  MRCVS  Diplomate ACVS  MICHAEL J. BOERO DVM  MS  Diplomate ACVS 《Veterinary surgery : VS》1995,24(6):506-514

Complications of celiotomy incisions were evaluated retrospectively in 274 horses that survived at least 1 month after surgery, or died or were euthanatized within 1 month of surgery, as a direct result of these complications. Horses were divided into four groups; group A, a ventral median celiotomy for intestinal disease; group B, ventral median celiotomy for nonintestinal disease; group C, repair of an umbilical hernia; and group D, celiotomy in a region other than the midline. Specific incisional complications were peri-incisional edema, drainage, incisional abscess, suture sinus, and dehiscence. Incision-related complications occurred in 30% of the horses (group A, 40%; group B 18%; group C, 7%; and group D, 88%). Complications occurred more frequently in group D than group A ( P =.009), which were higher than in groups B and C ( P <.00001). Incisional hernia occurred in 28 of 256 (11%) horses that survived at least 4 months and were available for follow-up. Hernia formation was more common ( P <.00001) in horses that had other incisional complications (23 horses) than those without (5 horses). Serous or purulent incisional drainage, were more likely to be associated with hernia formation than was serosanguineous drainage or other incisional complications.  相似文献   

Colonization of the canine skin with bacteria     

LEENA E. SAIJONMAA-KOULUMIES  DAVID H. LLOYD 《Veterinary dermatology》1996,7(3):153-162

Abstract Aspects of colonization of the canine skin with bacteria are reviewed. Owing to variability in sampling techniques, anatomical sites involved and lack of temporal studies, there is still controversy as to which bacteria are residents or transients on the canine skin. The establishment of the cutaneous flora is determined by the ability of bacteria to adhere to canine corneocytes, to use available nutrients from skin secretions and to resist challenge from competing bacteria. Variations in humidity and temperature due to environment, skin folds or differences in the haircoat are also likely to have an effect. Much research has focused around Staphylococcus intermedius, the main pathogen of the canine skin but its cutaneous residency status remains questionable. Pathological conditions such as atopy and seborrhoea favour the colonization of S. intermedius and predispose to infection. Recent studies indicate that bacterial interference as a method of preventing colonization of pathogenic staphylococci may be feasible. Résumé— Les aspects de la colonisation de la peau canine par des bactéries sont étudiées. A cause de la variabilité des techniques de prélèvements, des sites anatomiques, et du caratère ponctuel des études, le doute subsiste toujours quant à savoir quelle sont les bactéries résidentes ou transitoires sur la peau de chien. L'établissement d'une flore cutanée est déterminée par la capacité de la bactérie à adhérer aux cornéocytes canines, à utiliser les nutriments disponibles à partir des sécrétions cutanées et à résister aux autres bactéries qui concourent à l'occupation des memes sites. Les variations d'humidité et de température, dues à l'environnement, aux plis de peau et aux différences de pelage jouent probablement un role. La plupart des études concernent Staphylococcus intermedius, l'agent pathogène principal de la peau du chien, mais son statut de résident cutané est toujours débattu. Des conditions pathologiques telles que l'atopie et la séborrhée favorisent la colonisation par S. intermedius et prédisposent à l'infection. Des études récentes indiquent que l'interférence bactérienne peut être envisagée comme une méthode de prévention de la colonisation cutanée par un staphylocoque pathogène. [Saijonmaa-Koulumies, L. & Lloyd, D. H. Colonization of the canine skin with bacteria (Colonisation de la peau canine par des bactéries). Veterinary Dermatology 1996; 7 : 153–162.] Resumen Se revisan algunos aspectos de la colonización bacteriana en la piel canina. Existe aún controversia sobre qué bacterias son résidentes o transitorias en la piel del perro, debido a la variabilidad en las técnicas de recolección, localización y falta de estudios temporales. El establecimiento de la flora cutánea depende de su capacidad de adhesión a los corneocitos, de utilizar los nutrientes de las secreciones cutáneas y de resistir la competencia de otras bacterias. También es probable que tengan un papel los cambios de humedad y temperatura por los pliegues cutáneos o las diferencias en el pelaje. Se ha centrado mucha investigación en Staphylococcus intermedius, el principal patógeno de la piel canina, aunque se sigue cuestionando su existencia como residente cutáneo. Situaciones patológicas como la atopia o la seborrea favorecen la colonización por S. intermedius y predisponen a infección. Algunos estudios recientes indican que es factible la interferencia bacteriana como método de prevenir la colonización por estafilococos patógenos. [Saijonmaa-Koulumies, L. & Lloyd, D. H. Colonization of the canine skin with bacteria (Colonizacion de la piel cannina con bacterias). Veterinary Dermatology 1996; 7 : 153–162.] Zusammenfassung— Es werden Aspekte der Besiedelung der Hundehaut mit Bakterien dargestellt. Entsprechend der Variabilität in der Probenentnahme, verwendeten anatomischen Regionen und dem Mangel an temporären Studien exisitieren immer noch unterschiedliche Ansichten, ob Bakterien auf der Haut des Hundes als resident oder transient gelten. Die Aufstellung der kutanen Flora wird durch die Fähigkeit der Bakterien bestimmt, sich an die kaninen Korneozyten anzuheften, verfügbare Nährstoffe aus den Hautsekretionen zu verwenden und sich gegenüber konkurrierenden Keimen zu behaupten. Veränderungen in Feuchtigkeit und Temperatur in Abhängigkeit von Umgebung, Hautfalten oder Unterschieden im Haarkleid scheinen ebenfalls einen Effekt zu besitzen. Viele Untersuchungen konzentrierten sich auf Staphylococcus aureus, der hauptpathogene Keim auf der Hundehaut, aber sein Status als residenter Keim bleibt fraglich. Pathologische Zustände wie Atopie und Seborrhoe begünstigen die Besiedelung mit S. intermedius und prädisponieren für eine Infektion. Kürzliche Studien zeigen, daß bakterielle Interferenzen als Methode zur Verhinderung der Ansiedlung von pathogenen Staphylokokken möglich sein könnten. [Saijonmaa-Koulumies, L., Lloyd, D.H. Colonization of the canine skin with bacteria (Besiedelung der Haut des Hundes mit Bakterien). Veterinary Dermatology 1996; 7 : 153–162.]  相似文献   

隐子草地上生物量以及营养价值季节动态研究   总被引：1，自引：0，他引：1  

陈良  张春玲刘晶 DavidMichalk 《内蒙古草业》2002,14(2):39-41

本文主要探讨了隐子草地上生物量和营养成分以及体内体外消化率及其季节性变化动态。隐子草产量高峰期为7、8月份并且生长初期(5、6月)，它的枯黄部分较多而影响有机质和粗蛋白质含量以及体内体外消化率，到7月达最高值。并在8月份(隐子草的抽穗期)与其他牧草相比它的营养价值优良。  相似文献   

Development of a Free Latissimus Dorsi Muscle Flap in Cats     

STACEY A. NICOLL DVM  MVSc    J. DAVID FOWLER DVM  MVSc  Diplomate ACVS    AUDREY M. REMEDIOS DVM  MVSc  Diplomate ACVS    J. BRIAN CLAPSON MD  FRCS  D. GEORGE MD  FRCPC 《Veterinary surgery : VS》1996,25(1):40-48

Anatomic and experimental evaluation of the feline latissimus dorsi muscle was performed to assess its potential use as a free muscle flap. In the anatomic study, nonselective angiography of the subscapular artery was performed in nine heparinized feline cadavers. The muscle dimensions and vascular anatomy of the dissected latissimus dorsi muscle were recorded. In the experimental study four cats underwent heterotopic transplantation of a partial latissimus dorsi flap, and three cats underwent orthotopic transplantation of a complete latissimus dorsi flap. The mean length and width of the latissimus dorsi muscle was 19.0 and 5.4 cm, respectively. The dominant vascular pedicle was the thoracodorsal artery and vein. The average length and diameter of the thoracodorsal artery was 2.7 cm and 0.6 mm, respectively. Minor vascular pedicles were provided by branches of the intercostal arteries. Numerous choke anastomoses existed between the two pedicle systems. Viability of muscle flaps based on subjective evaluation, angiography, and histopathology, was 66% and 100% in the heterotopic and orthotopic studies, respectively. Flap failure seemed to be caused by both arterial and venous thrombosis. The latissimus dorsi muscle flap met criteria required for application in microvascular reconstruction. The vascular pattern was appropriate and consistent. Donor site morbidity was low, whereas surgical accessibility was high. The muscle satisfied the physical criteria of a free flap. Long-term anastomotic patency and flap viability was shown.  相似文献   

Comparative Evaluation of Two Surgical Scrub Preparations in Cattle     

ANDRÉ DESROCHERS DMV  MS    GUY ST-JEAN DMV  MS  Diplomate ACVS    DAVID E. ANDERSON DVM  MS  Diplomate ACVS    DONNA P. ROGERS BS  M.M. CHENGAPPA BVSc  PhD  Diplomate ACVM 《Veterinary surgery : VS》1996,25(4):336-341

One hundred seventeen cattle that had undergone surgery were assigned randomly to two preoperative skin preparation protocols. Group 1 (60 animals) skin preparation was with povidone-iodine soap and isopropyl alcohol, whereas group 2 (57 animals) had skin preparation with chlorhexidine gluconate and isopropyl alcohol. Quantitative microbial culture plates were used to estimate the number of colony forming units (CFUs) before skin preparation (prescrub), after skin preparation (postscrub), after surgery (postoperative), and in room air (environment). A significant decrease in CFU occurred postscrub for both skin preparations ( P <.05). Chlorhexidine and alcohol preparation resulted in significantly fewer CFUs (LSMean ± SE = 2.79 CFU ± 1.74) and a greater percentage reduction in CFUs (98.64%± 2.01) postscrub than povidone and alcohol (LSMean ± SE = 10.27 CFUs ± 1.51, 93.29%± 1.85); ( P <.005). Group 2 had a significantly higher frequency of negative cultures postscrub (49.1%) compared with group 1 (18.3%) ( P <.001). The number of postoperative CFUs were not significantly different between the two treatment groups. Wound infection frequency for clean surgical procedures was not significantly different between the two skin preparation protocols (group 1 = 9.8%, group 2 = 10.7%), however, infection frequency was significantly higher for surgical procedures with a ventral abdominal approach (5 of 14, 35.7%), compared with a flank approach (1 of 41, 2.4%) or other approaches (orthopedic procedures) (1 of 16, 6.3%) ( P <.05). Both skin preparation protocols were effective and safe in decreasing the skin microflora population of cattle before surgery and although preparation with chlorhexidine gluconate and alcohol resulted in less CFUs immediafly postscrub, the frequency of surgical wound infection was similar for both protocols.  相似文献   

Diarrhoea in Merino ewes during winter: association with trichostrongylid larvae     

DAVID B. ADAMS 《Australian veterinary journal》1995,72(2):75-75

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Percutaneous absorption of gentamicin by the leopard frog, Rana pipiens     

J. EDMOND RIVIERE  DAVID P. SHAPIRO  GORDON L. COPPOC 《Journal of veterinary pharmacology and therapeutics》1979,2(3):235-239

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Orthotopic Osteochondral Transplantation of the Canine Proximal Femur     

DAVID STOLOFF D.V.M.  M.S…  ‡  HUGH C. BUTLER D.V.M.  M.S.  §  MARK M. GUFFY D.V.M.  M.S.  † § HORST W. LEIPOLD D.V.M.  PH.D.  § 《Veterinary surgery : VS》1979,8(2):38-45

An 18-week study was conducted to evaluate orthotopic osteochondral transplantation of the proximal femur in the dog. Eighteen dogs were divided into 3 groups of 6 each. The first group received autografts, the second received fresh allografts, and the third received grafts that had been frozen in a bone bank for 24–28 days. The grafts were fixed in position using dynamic compression plates. The grafted limbs were maintained in a sling and thus were nonfunctional and non-weight bearing throughout the 18-week study. Postoperatively the dogs were given oral tetracycline to assess osteo- cyte viability. The dogs were radiographed at 2–week intervals and 1 dog in each group was euthanatized every 3 weeks. The femurs were examined using standard histopathologic and fluorescent labeling techniques. All femoral heads were luxated by the 2nd postoperative week. The bones of all the femoral heads underwent avascular necrosis and degenerative changes were present in the transplanted cartilage by the 6th postoperative week. During the first 18 weeks following transplantation there was little radiographic and histologic difference among the 3 types of grafts regarding the nature and rate of bone healing. Based on the data obtained from techniques utilized in this study, the femoral head, neck, and articular cartilage did not survive, while the femoral diaphysis did survive the transplantation process. Different techniques may alter to some degree the results obtained.  相似文献