Recent advances in computational fluid dynamics relevant to the modelling of pesticide flow on leaf surfaces

Increasing societal and governmental concern about the worldwide use of chemical pesticides is now providing strong drivers towards maximising the efficiency of pesticide utilisation and the development of alternative control techniques. There is growing recognition that the ultimate goal of achieving efficient and sustainable pesticide usage will require greater understanding of the fluid mechanical mechanisms governing the delivery to, and spreading of, pesticide droplets on target surfaces such as leaves. This has led to increasing use of computational fluid dynamics (CFD) as an important component of efficient process design with regard to pesticide delivery to the leaf surface. This perspective highlights recent advances in CFD methods for droplet spreading and film flows, which have the potential to provide accurate, predictive models for pesticide flow on leaf surfaces, and which can take account of each of the key influences of surface topography and chemistry, initial spray deposition conditions, evaporation and multiple droplet spreading interactions. The mathematical framework of these CFD methods is described briefly, and a series of new flow simulation results relevant to pesticide flows over foliage is provided. The potential benefits of employing CFD for practical process design are also discussed briefly. © Crown copyright 2009. Reproduced with permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.     

Orbital cellulitis associated with Toxocara canis in a dog

Reports of Toxocara canis ocular larva migrans are uncommon in animals, with only a few cases reported. Most reports involve larval migration into the retina and choroid, with parasitic invasion of the orbit reported only in experimental studies. This is the first clinical case of Toxocara canis infection in the retrobulbar region of a 10-year-old, cross-bred male dog presenting with unilateral orbital cellulitis. Ophthalmic signs included protrusion of the nictitating membrane, chemosis, exophthalmos and hypertropia. The parasite was diagnosed by histologic and parasitologic examination of orbital tissues, which were removed during enucleation.     

Serotypes and antibiotic sensitivity of Moraxella bovis isolated from an outbreak of infectious bovine keratoconjunctivitis.

Samples of conjunctival fluid of four calves, from a herd with infectious bovine keratoconjunctivitis, were collected five times at monthly intervals and from another 16 calves in the initial stages of the disease, were collected only once. Moraxella bovis was recovered from 82.3% of the samples. Twenty-six isolates were typed with polyvalent sera and 25 with monovalent sera. The antibiotic sensitivity of 13 isolates was also studied. Twenty of the 26 isolates reacted with polyvalent sera and 16 of 25 tested isolates, reacted with monovalent sera. The isolates recovered from the same animal in a different collection or from a different animal in the same collection did not always belong to the same serogroup. Different serotypes were prevalent in each collection. Differences in the antibiotic sensitivity of the isolates were also detected.     

Aspergillosis in camels affected with a specific respiratory and enteric syndrome

During the summer of 1990 deaths, occurred in racing camels (Camelus dromedarius) associated with a specific disease syndrome. Clinical signs included pyrexia, coughing, lachrymation, oedema of the throat and submandibular region and enlargement of submandibular lymph nodes. In terminal cases nervous signs were present and sometimes there was bloody diarrhoea and vomiting. Of 480 camels at least 70 animals were affected with the disease and about 40 died. Morbidity and mortality was greater in camels recently imported. Consistent necropsy findings were extensive petechial and ecchymotic haemorrhage beneath the epicardium, endocardium and visceral pleura and in the mediastinal lymph nodes, and haemorrhagic oedema of the pharyngeal and laryngeal areas. Haemorrhages occurred more variably in abdominal organs and on the omasal and abomasal mucosa. Bronchopneumonia, omasitis and abomasitis were observed on microscopic examination, together with liver and kidney lesions of presumed toxic origin. Fungal hyphae and, occasionally, the characteristic conidial morphology of Aspergillus fumigatus were seen in sections and direct smears from lesions in the respiratory and alimentary tracts. A fumigatus was cultured from trachea, bronchi, bronchioles, lung tissue, heart blood, omasum, abomasum, ileum and submandibular lymph nodes. Whether the role of Aspergillus in the overall syndrome is primary or secondary has not been established; no other potential aetiological agent has been identified.     

Activity of the Pinus elliottii resin compounds against Lernaea cyprinacea in vitro

Lernaea cyprinacea infestation is a major problem for fishing culture in Brazil, which was introduced in the mid-eighties. To attempt controlling this parasite, an evaluation of the activity of the Pinus elliottii resin constituents against it was undertaken. To run the bioassay, fish infested with L. cyprinaceae were transferred to aquaria and kept at room temperature and ventilation for 15 days for adaptation. Afterwards, fish were sacrificed and the parasites were kept under water to run the experiments by evaluating the activities of the steamed oil and the chloroform fraction of the resin at concentrations of 0.5, 1.0, 2.0 and 5.0 ppm. The crude resin was also evaluated at concentrations of 1.0, 5.0 and 10 ppm, as well as the major components of its steamed oil, alpha and beta-pinenes, both at concentrations of 0.5 and 1.0 ppm. The results showed that both fractions from the resin were effective at 0.5 ppm concentration, while the pure compounds were less active. Moreover, the acute toxicity (DL(50)) of the crude resin for the fish Leptorinus piau, aged 1 month, was established at 200.0 ppm, which ensures its safe use.     

Evaluation of Three Enzyme Immunoassays for Diagnosis of Clostridium difficile–Associated Diarrhea in Foals

The aim of the present study was to compare the test performances of three commercial enzyme immunoassays (EIAs) against the toxigenic culture using the cytotoxicity assay as the gold standard. All EIAs showed >78% sensitivity, and the lowest specificity was 92.6%. These results suggest that EIAs could be useful for the diagnosis of Clostridium difficile infection in foals.     

Enrichment of Y‐Chromosome‐Bearing Bull Spermatozoa by Swim‐up Through a Column

With the advancement of assisted reproductive biotechnologies, preselecting the sex of offspring has become an important goal for cattle and other livestock breeding as well as for research. The aim of this study was to investigate the feasibility of producing enriched pools of X‐ or Y‐chromosome‐bearing sperm by vertical swim‐up through a long, narrow column. Sperm recovered from the top portion of the column was predominantly Y‐bearing (60%, p < 0.05), which were capable of fertilizing matured oocytes and produce significantly more male embryos compared with standard swim‐up protocol.     

安徽特色农业可持续发展研究

当前安徽特色农业呈不断发展趋势：专业化和产业化不断增强、基础设施逐步改善、科技扶持力度不断增强、农业旅游等功能有所拓展。但是也存在优良品种保护和开发力度不够,生产技术水平相对较低,基层农技推广和农村实用人才难以满足需求,基础设施建设投入不足,主产区生态环境保护不够,产业化有待推进,休闲、观光旅游功能拓展缓慢等问题。建议从五个方面推进安徽特色农业可持续发展：加强基层农业科技人才开发;推进特色农业产业化发展;加强优良品种开发与保护;完善农业基础设施建设;保护生态环境,发展农业旅游。     

Leishmaniasis and malaria: new tools for epidemiologic analysis

Parasitic diseases are still prevalent in many parts of the world, causing both human suffering and economic loss. Recent developments in biotechnology, such as the use of monoclonal antibodies and recombinant DNA, have the potential for providing both more extensive and detailed information on the parasite in the infected human and in insect vectors. New methods of detection, both in man and insect vectors, have been developed for two parasitic diseases, leishmaniasis and malaria. These new methodologies will be important in epidemiologic studies on the prevalence and transmission of these parasitic diseases.     

Diisopropylfluorophosphate: suppression of ionic conductance of the cholinergic receptor

When frog sartorius muscles were exposed to diisopropylfluorophosphate, the amplitude and half-decay time of the end-plate current decreased; the half-decay time became almost potential-independent and the equilibrium potential for the end-plate current was more negative than during control conditions. When the excess reagent was removed by washing so that only the phosphorylated acetylcholinesterase remained, the amplitude of the end-plate current was restored, while its half-decay time was markedly increased. These findings reveal that this organophosphate significantly affects the receptor-ionic conductance modulator complex in addition to its well-known anticholinesterase activity.