Development of an enzyme-linked immunosorbent assay for the detection of dicamba

A competitive indirect enzyme-linked immunosorbent assay (CI-ELISA) was developed to quantitate the herbicide dicamba (3,6-dichloro-2-methoxybenzoic acid) in water. The CI-ELISA has a detection limit of 2.3 microg L(-1) and a linear working range of 10--10000 microg L(-1) with an IC(50) value of 195 microg L(-1). The dicamba polyclonal antisera did not cross-react with a number of other herbicides tested but did cross-react with a dicamba metabolite, 5-hydroxydicamba, and structurally related chlorobenzoic acids. The assay was used to estimate quantitatively dicamba concentrations in water samples. Water samples were analyzed directly, and no sample preparation was required. To improve detection limits, a C(18) (reversed phase) column concentration step was devised prior to analysis, and the detection limits were increased by at least by 10-fold. After the sample preconcentration, the detection limit, IC(50), and linear working range were 0.23, 19.5, and 5-200 microg L(-1), respectively. The CI-ELISA estimations in water correlated well with those from gas chromatography-mass spectrometry (GC-MS) analysis (r(2) = 0.9991). This assay contributes to reducing laboratory costs associated with the conventional GC-MS residue analysis techniques for the quantitation of dicamba in water.     

蝗虫微孢子虫病在优势蝗虫种类中的持续传播

对施用蝗虫微孢子虫后1-10年的草场中5种主要蝗虫种群中微孢子虫病的流行状况进行了研究,结果表明,蝗虫微孢子虫病能在蝗群中长期传播,蝗虫种群的感病率和感染指数呈波动趋势,随着施用后年限的增加,波幅变动范围趋于稳定。感染率波幅范围为20％-80％,感染指数为10％-41％;鼓翅皱膝蝗、白边痂蝗和毛足棒角蝗种群对微孢子虫病的感染指数,不同年份波动较大,短期内难以形成一个稳定的流行群体;而在小车蝗和宽须蚁蝗种群中引入微孢子虫4年后,感染指数下降,但能够形成比较稳定的感染群体。     

Soil surface drip point features: an integrated approach using analytical photogrammetry and soil micromorphology

This study considers changes occurring on a soil surface after exposure to simulated rainfall. The soil surface in question has a crop cover of artificial maize, and interest focuses specifically on the surface features produced by leaf drips. An analytical photogrammetric approach is used to examine surface morphological change at a small scale (1 mm). These topographical changes are then related to sub-surface crust development as observed by the use of impregnated polished blocks. For the first time therefore soil surface and soil sub-surface changes are integrated together in one study. The results reveal a ‘cut and fill' type process in which aggregate welding and breakdown operate in parallel.     

辣椒新品种华美105的选育

华美105是以自交系HA015为母本,以抗CMV的株系LR002为父本杂交育成的螺丝形羊角椒。早熟,从定植到始收45 d(天)左右,首花节位在第9～10节。植株健壮,生长势强,叶片小,节间短,耐低温弱光。连续坐果能力强,单株结果 25～30个,单果质量80～120 g,产量稳定在8 500 kg·(667 m~2)~(-1)以上。青熟果深渌色,老熟果红色,辣味中等,肉质脆嫩,市场接受度高。田间对CMV和疫病的抗性强于对照陇椒3号。适合北方早春、秋延后、越冬设施及南方露地栽培。     

不同时期滴灌氮量对冀西北坝上地区洋葱产量和品质的影响

以洋葱品种"红贝特"为试材,设4个施氮水平处理N0、N1、N_2、N3,以CK为对照,测定了膜下滴灌洋葱的植株性状、鳞茎性状、品质和产量等指标,以探讨冀西北坝上地区地膜覆盖洋葱适宜的滴灌氮量,给当地洋葱施肥提供合理施肥依据。结果表明:处理N1的植株性状、鳞茎性状均显著高于CK,产量较CK提高12.26%;处理N1可溶性蛋白质、可溶性固形物、可溶性糖和维生素C含量较CK分别增加27.13%、8.16%、19.15%和60.71%,而硝酸盐含量CK较N1提高85.67%;在该试验条件下,洋葱获得最佳效益时的氮肥施用量和时期分别为苗期追N 31.5kg·hm~(-2),茎叶生长期追N 47.25kg·hm~(-2),鳞茎膨大初期追N 47.25kg·hm~(-2),鳞茎膨大中期追N 31.5kg·hm~(-2),并在整个生长时期配施P_2O_575kg·hm~(-2),配施K_2O 255kg·hm~(-2)。     

Photonic band gap guidance in optical fibers

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.     

A cross-sectional study of geriatric horses in the United Kingdom. Part 2: Health care and disease

Reasons for performing study: Geriatric horses (aged ≥15 years) represent a substantial proportion of the equine population, yet very few studies have investigated the prevalence of diseases within the UK equine geriatric population. Objectives: To describe the provision of routine preventive health care measures, prevalence of clinical signs of disease and the prevalence of owner reported diseases. Additionally, the effect of increasing age on the provision of preventive health care and the presence or absence of clinical signs and disease was assessed. Methods: A cross‐sectional study was conducted, surveying a randomly selected sample of veterinary registered owners with horses aged ≥15 years, using a self‐administered postal questionnaire. Results: As geriatric horses increased in age, there was a reduction in the provision of preventive health care measures, such as vaccination, farrier care and routine veterinary checks. Only 68.7% of horses had received a routine veterinary visit within the previous 12 months. Owners frequently observed clinical signs in their animals, with 77% reporting at least one clinical sign of disease. Increasing age was associated with increased reporting of many clinical signs of disease. Over half (58%) of horses had at least one episode of disease within the previous 12 months, yet only 31% of owners reported that their animal currently suffered from a known disease or disorder. Conclusions and potential relevance: Although owners frequently observed clinical signs in their aged horse, there may be incorrect or under recognition of many diseases and health problems. Reduced frequency of routine preventive health care measures, along with suboptimal owner recognition of health and welfare problems may lead to compromised welfare in the geriatric population.