Weed control in conventional and herbicide tolerant winter oilseed rape (Brassica napus) grown in rotations with winter cereals in the UK

Two winter oilseed rape (Brassica napus) cultivars, tolerant to glyphosate and glufosinate, were compared with a conventional cultivar at three sites over 4 years, in 3‐year crop rotations in the UK. The winter oilseed rape was grown in Years 1 and 4, with winter cereals, which received uniform herbicide treatments, in the intervening years. The second winter oilseed rape treatments were applied to randomised sub‐plots of the original plots. Weed densities were recorded in autumn and spring and weed biomass was measured in summer. At most sites, there was only one application of glufosinate or glyphosate, whereas two products were often used on the conventional variety. The timing of glyphosate and glufosinate application was, on average, 34 days later than that of the conventional broad‐leaved weed control treatments. Overall weed control, across all sites and years, was not statistically different between the conventional, glyphosate and glufosinate treatments. However, glyphosate achieved higher control of individual weed species more frequently than the other treatments. Glufosinate and the conventional treatments were similar in performance. The treatments in Year 1 sometimes affected weed populations in the subsequent cereal crops and, in rare instances, those in the rape in Year 4. Carry‐over effects were small after most treatments. In general, weed survival was greater in the oilseed rape crops, irrespective of the treatment, than it was in the intervening cereal crops.     

Partial Arytenoidectomy in the Horse with and without Mucosal Closure

Left-sided partial arytenoidectomy was performed in eight horses to evaluate healing. Four horses underwent conventional partial arytenoidectomy with suture apposition of the mucosa. In four horses, most of the arytenoid cartilage, including overlying mucosa, vocal fold, and laryngeal saccule, were excised en bloc without mucosal closure. The horses were monitored clinically by endoscopic examination. One horse from each group was euthanatized at weeks 2, 4, 8, and 16. Complete necropsies with gross and histologic examination of the arytenoidectomy sites were performed. Postoperative complications such as coughing, dysphagia, and aspiration pneumonia were not encountered and problems with wound healing were minimal in both groups. The defect created by partial arytenoidectomy without mucosal closure initially filled to the level of the luminal surface with granulation tissue, with a gradual transition to mature fibrous connective tissue. Grossly, the defect appeared to be healed and was completely epithelialized by week 16 without apparent narrowing of the laryngeal lumen. Partial arytenoidectomy sites with mucosal closure healed in a similar pattern by week 8. Partial dehiscence of the dorsal portion of the sutured mucosa occurred in three horses.     

A review of the biology of canine skin with respect to the commensals Staphylococcus intermedins, Demodex canis and Malassezia pachydermatis

Abstract Skin disease associated with the cutaneous commensal organisms Staphylococcus intermedius, Malassezia pachydermatis and Demodex canis is frequently encountered in veterinary medicine. In treatment the aim is elimination of the commensal, but recurrence of skin disease is not unusual. In this review, these potentially pathogenic commensals and their ecology are discussed with particular reference to skin biology and the surface ecosystem. The strategies employed by the micro-organisms for survival and the defence mechanisms of the host are considered. Disease occurs when the virulence of the commensal overwhelms the resistance of the host. It is hoped that an understanding of the complex nature of the skin and its commensals will lead to a better understanding of those diseases associated with commensals and in consequence more effective treatment. Résumé— Les dermatoses associées aux organismes commensaux cutanés Staphylococcus intermedius, Malassezia pachydermatis et Demodex canis sont fréquentes en médecine vétérinaire. Le traitement vise àéliminer le commensal, mais les récidives sont fréquentes. Dans cet article, les commensaux potentiellement pathogènes et leur écologie sont discutés avec une référence particulière à la biologie cutanée et à l'écosystème de surface. Les stratégies employées par les microorganismes pour survivre et les mécanismes de défense de l'hote sont présentés. La pathologie se développe lorsque la virulence du commensal outrepasse la résistance de l'hote. Il faut espérer que la compréhension de la nature complexe de la peau et de ses commensaux, permettent une meilleure compréhension des pathologies associées à ces commensaux et par conséquent un traitement plus efficace. [Mason, I. S., Mason, K. V., Lloyd, D. H. A review of the biology of canine skin with respect to the commensals Staphylococcus intermedius, Demodex canis and Malassezia pachydermatis (Une revue de la biologie de la peau concernant les commensaux Staphylococcus intermedius, Demodex canis et Malassezia pachydermatis). Veterinary Dermatology 1996; 7 : 119–132.] Resumen En medicina veterinaria son frecuentes las dermatopatías asociadas a los microorganismos comensales Staphylococcus intermedius, Demodex canis y Malassezia pachydermatis. El tratamiento busca la eliminatión del comensal, aunque no son raras las recidivas. En esta revisión se discute la ecología de estos comensales potencialmente patógenos, con especial énfasis en la biologia cutánea y el ecosistema superficial. Se tienen en cuenta las estrategias para la supervivencia utilizadas por los microorganismos y los mecanismos de defensa del huésped. La enfernedad se desarrolla cuando la virulencia del comensal supera la resistencia del huésped. Se espera que el mejor conocimiento de la naturaleza compleja de la piel y de sus comensales llevará a un mejor conocimiento de las enfermedades asociadas a los comensales y, consecuentemente, a un tratamiento más efectivo. [Mason, I. S., Mason, K. V., Lloyd, D. H. A review of the biology of canine skin with respect to the commensals Staphylococcus intermedius, Demodex canis and Malassezia pachydermatis (Revision de la biologia cutánea con respecto a los comensales Staphylococcus intermedius, Demodex canis y Malassezia pachydermatis). Veterinary Dermatology 1996; 7 : 119–132.] Zusammenfassung— Hauterkrankungen in Verbindung mit den kutanen, kommensalen Organismen Staphylococcu intermedius, Malassezia pachydermatis und Demodex canis werden in der Veterinärmedizin häufig angetroffen. Das Ziel der Behandlung ist die Elimination der Kommensalen, aber die Rezidivierung der Hauterkrankung ist nicht ungewöhnlich. In dieser Übersicht werden diese potentiell pathogenen Kommensalen und ihre Ökologie mit speziellem Bezug zur Biologie der Haut und des Ober-flächenökosystems diskutiert. Die Überlebensstrategien dieser Mikroorganismen und die Abwehrmechanismen des Wirtes werden berücksichtigt. Eine Erkrankung tritt auf, wenn die Virulenz des Kommensal die Widerstandskraft des Wirtes übertrifft. Man hofft, daß das Verstehen der komplexen Natur der Haut und ihrer Kommensalen zum besserem Verständnis dieser mit den Kommensalen verbundenen Krankheiten und damit in der Folge zu wirksamerer Behandlung führt. [Mason, I.S., Mason, K.V., Lloyd, D.H. A review of the biology of canine skin with respect to the commensals Staphylococcus intermedius, Demodex canis and Malassezia pachydermatis (Übersicht über die Biologie der Haut des Hundes mit Berücksichtigung der Kommensalen Staphylococcus intermedius, Demodex canis und Malassezia pachydermatis). Veterinary Dermatology 1996; 7 : 119–132.]     

Yield of white clover populations in mixture with contrasting perennial ryegrasses

A field experiment was established in May 1986 in which four white-clover populations originating in Switzerland, and a bred variety, Menna, were grown in binary mixtures with their 'co-existing' perennial ryegrasses and three other bred ryegrasses— Aurora, Talbot and Melle. The productivity of both components of the mixtures was measured by cutting samples in October 1986 (after establishment) and on five occasions during the growing season in 1987, Substantial differences were observed between clover yields in different mixtures, and the yield ranking of clover was found to vary with companion grass. It was concluded that the interaction between grass and clover populations originated at an early stage in sward development, being evident in both the 1986 establishment cut and the spring cut of the following year. The implications of these results for the formulation of breeding objectives and the evaluation of breeding material are briefly discussed.     

The effect of homoeologous group 7 chromosomes upon adult plant resistance of wheat to yellow rust (Puccinia striiformis)

Aneuploid and intervarietal chromosome substitution lines of wheat ev. Chinese Spring were used to study the effects of homoeologous chromosomes 7A, 7B and 7D upon adult plant resistance to yellow rust ( Puccinia striiformis). Chromosomes 7B and 7D carry factors upon their short arms which interact to influence resistance. The results can be explained if there is a single locus determining resistance upon the short arms of chromosomes 7B and 7D. These loci may be homoeo-allelic; however, no evidence was found for a corresponding locus upon the short arm of chromosome 7A. Three homologous variants of the factor on 7D^S were found but no variation was found for the factor on 7B^S.     

INTRODUCTION TO DICOM FOR THE PRACTICING VETERINARIAN

Digital Imaging and Communication in Medicine (DICOM) is a communication protocol that imaging devices use to communicate. The universal acceptance of the DICOM standard by the major medical vendors means that the digital transition in veterinary medicine should be relatively smooth provided DICOM is used. DICOM service objects, roles, service classes, and conformance standards are discussed. The authors strongly encourage the use of image acquisition software and image archive systems that support the DICOM standard.     

中空纤维超滤澄清果汁时浓差极化现象的产生原理及对策

本文阐述了中空纤维超滤膜澄清果汁时浓差极化现象的产生原理,并从正反向进料,加压及反冲等方面分析了对策 。     

Annual losses of iron from moorland soils and their relation to free iron contents

The temporal pattern of iron loss from a moorland catchment was investigated by intensive stream water sampling. The total loss in 1 year was 2.11 kg ha^?1 of Fe, with a pronounced autumn maximum. Iron concentrations in stream water were strongly correlated with dissolved organic matter content, but again with seasonal variation. Free iron content measured on a number of soils in the catchment ranged from 3.1 to 8.7 kg m^?2. Assuming soil development over 10 000 years, predicted loss of iron from the catchment is comparable in quantity to the amounts of free iron in the soils.